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Loper: A quadruped-hybrid stair climbing robot
Abstract
The purpose of this paper is to describe the Loper, a multi-purpose robotic platform under development at the University of Minnesota's Center for Distributed Robotics. Leper's unique Tri-lobe wheel design and highly compliant chassis make the platform especially suited for overcoming many of the challenges associated with search operations in urban settings. The mechanically simple design and use of commercially available components make Loper easily maintainable. The platform also features long operational time, onboard sensor processing, dedicated motion control, and four reconfigurable sensor bays.
... Looper [86]. Adapted with permission from ref. [86] 2008 ...
... Looper [86]. Adapted with permission from ref. [86] 2008 ...
... Sam D. Herbert Krys [84,85] Prototype solution, segmented stair-climbing wheels Looper [86]. Adapted with permission from ref. [86] 2008 Sam D. Herbert ...
Stair climbing is one of the most challenging tasks for vehicles, especially when transporting people and heavy loads. Although many solutions have been proposed and demonstrated in practice, it is necessary to further improve their climbing ability and safety. This paper presents a systematic review of the scientific and engineering stair climbing literature, providing brief descriptions of the mechanism and method of operation and highlighting the advantages and disadvantages of different types of climbing platform. To quantitatively evaluate the system performance, various metrics are presented that consider allowable payload, maximum climbing speed, maximum crossable slope, transport ability and their combinations. Using these metrics, it is possible to compare vehicles with different locomotion modes and properties, allowing researchers and practitioners to gain in-depth knowledge of stair-climbing vehicles and choose the best category for transporting people and heavy loads up a flight of stairs.
... The legs have a limited rotation angle. In wheeled mode, feet [18], (b) The PAW robot executing an inclined turn [19], (c) Hylos wheel-legged robot [20], (d) Chariot III [21], (e) Wheeleg robot [22], (f) Robot Octal Wheel [23], (g) Hanzo [24], (h) Space Rover [25], (i) Loper [26], (j) Epi-q1 [27]. turn and provide movement on the wheel. ...
... Space Rover robot (Fig. 1h) has a specific system configuration with wheels and intermediate self-adjusting tie rods to ensure proper body posture and enhance stability on the stairs and highland [25]. The Loper robot (Fig. 1i) has a unique combination of Tri-lobe wheels and a very similar chassis [26]. This design allows it to easily cross uneven terrains. ...
... The ratio of obstacle height and leg length is only 1.32. Similarly, the relatively large dimension of rigid legs is required for IMPASS [34], Loper [26], and Asguard [33], Transformable Wheel Robot with A Passive Leg [3], Shape-Morphing Wheel Designed Robot [49]. Although the conversion rate of Transformer Robot [42,43] and WheeLeR [50] is higher than the FUHAR robot, the maximum obstacle height that it can overcome is 150 and 80 mm. ...
HIGHLIGHTS-This paper introduces a mobile robot with a new type of transformable wheel legs that can be used for flat and rough terrain.-It integrates the stability and maneuverability of a wheeled robot and the legged robot's obstacle climbing capacity using a transformable mechanism with wheel legs.-Dynamic modeling and design of a control system were obtained. Simulation of robot's prototype was designed and produced. Highlights J o u r n a l P r e-p r o o f Journal Pre-proof Robotics and Automation Systems xxx (2020) xx-xx Transformable wheel-legged robot Motion analysis Obstacle Avoidance Dynamic Model A B S T R A C T This paper introduces a mobile robot with a new type of transformable wheel legs that can be used for flat and rough terrain. It integrates the stability and maneuverability of a wheeled robot and the legged robot's obstacle climbing capacity using a transformable mechanism with wheel legs. With a transformation structure based on a four-bar mechanism, these two modes can be easily changed. This paper analyzes the movements for the proposed robot in wheeled and legged mode. Dynamic modeling and design of a control system were obtained. Then, the obstacle climbing strategies under legged modes were carried out. Finally, on the basis of the simulation, a prototype of the proposed robot was designed and produced. The results from the experiments validate the efficiency of the designed hybrid mobile robot.
... mR max ω 2 cos γ = −f (11) mR max ω 2 sin γ = mg − F N − F y (12) M + F N R max cos γ − fR max sin γ − F y L cos ε = 0 (13) From the geometric features, the relation of H s and γ can be described as follow L sin ε = H s + R max sin γ (14) The moment M is obtained by converting gravity from point C to point P as M = mgd cos ε (15) Then normal force F N is determined by Eq. (11) to Eq. (15) as ...
... mR max ω 2 cos γ = −f (11) mR max ω 2 sin γ = mg − F N − F y (12) M + F N R max cos γ − fR max sin γ − F y L cos ε = 0 (13) From the geometric features, the relation of H s and γ can be described as follow L sin ε = H s + R max sin γ (14) The moment M is obtained by converting gravity from point C to point P as M = mgd cos ε (15) Then normal force F N is determined by Eq. (11) to Eq. (15) as ...
... The ratio of obstacle height and leg length is only 1.32. Similarly, relative large dimension of rigid legs are required for IMPASS [14], Loper [15], and Asguard [16]. For the stepping triple wheel robots [23,24], the max efficient height of wheel has to be larger than obstacles. ...
This paper proposes a new type of transformable wheel-legged mobile robot that could be applied on both flat and rugged terrains. It integrates stability and maneuverability of wheeled robot and obstacle climbing capability of legged robot by means of a wheel-legged transformable mechanism. These two modes can be switched easily with two spokes touching terrain. In this paper, the motion analysis of the proposed robot under wheeled mode, legged mode and transformable mode are carried out after briefly introducing the concept and control system design. Then, the obstacle climbing strategies under wheeled and legged modes are obtained. Finally, a prototype of the proposed robot is designed and manufactured based upon the simulation analysis. And the experiment results validate the effectiveness of the proposed transformable wheel-legged mobile robot.
... LOPER is a quadruped-hybrid stair climbing robot with tri-lobe wheel similar to those of MSRox [183]. However, unlike the wheel of MSRox, the tri-lobe wheel of LOPER always rotates irrespective of surrounding environment. ...
... It is noteworthy that when the stair-climbing locomotion of mobile robots is based on a so-called star-wheel consisting of three wheels, special control strategy for stair-climbing is not indispensable: when the star-wheel increases the wheel radius of mobile robot, its stair-climbing ability has naturally improved [95], [97], [100], [183]. Tables I, II, III and IV summarize the characteristics of tracked, legged, wheel-linkage and wheel-legged robots, respectively. ...
Indoor service robots have been widely introduced in the fields of cleaning, delivery, education, guidance, and healthcare, etc. in indoor environments. The mobility of an indoor service robot is essential to expanding its applications. However, the mobility of existing indoor service robots is highly limited by surrounding indoor environments. For example, a stair is one of the major obstacles that restrict the reachable areas of indoor service robots. Even though many studies have been performed to develop reliable and fast stair-climbing robots based on legged, tracked, wheel-legged and wheel-linkage mechanisms, a market-dominant stair-climbing robot remains unsolved. This review investigates the efforts of engineers devoted to stair-climbing robots. To this end, the locomotion mechanisms of stair climbing robots are classified and their sensing method are summarized. In this review, we also propose useful criteria for evaluating the stair-climbing ability of an indoor service robot. By virtue of these criteria, the stair-climbing performance of existing robots are qualitatively compared. We hope this review helps develop the reliable and fast stair-climbing robots and the reasonable criteria for their performances.
... The mode is changed when moving along flat ground and in step climbing. The prototype model that focused on this movement method is Loper [4]. Loper is a quadruped-hybrid stair-climbing robot developed by Sam D. Herbert. ...
... We devised a way to move the center of gravity when crawl gait is performed with the prototype model as shown in Fig. 9. The phase changes in the order of (1), (2), (3), (4). The phases of the arc side of the wheels (blue arrows) are respectively shifted by 60 degrees, and the liner side of the wheels (red arrows) rotate at three times the speed of the arc side. ...
Abstract This paper describes development of a mobile robot using semicircular wheels on uneven terrain. It performs the crawl gait on flat ground without changing potential energy and the butterfly gait to climb over debris. We also used crawl gait to perform turning motion. The butterfly gait is used to climb over high steps. Turning motion is achieved not only by creating a difference in angular velocity between the wheels on both sides, but also by keeping the crawl gait. We achieved continuous movement from turning motion to pivot turning. We conducted an experiment on the movement and turning motion on flat ground using crawl gait.
... They usually require dynamic gait planning based on inertial forces. Other robots, such as Loper (Herbert et al., 2008), Epi.q-1 (Quaglia et al., 2010), and Mars Rover (Toupet et al., 2020), have wheels mounted on the rotatable wheel-arm mechanism, and thereby increase the ability for rough terrain negotiation. They employ mechanical principles to simplify their control. ...
This paper presents the design and control of Q-Whex, an untethered, quasi-wheeled hexapod robot. Q-Whex has only six actuators-one motor located at each hip-achieving mechanical simplicity that promotes reliable and robust operation in real-world tasks. All of the robot's mechanical parts are simply fabricated with carbon fiber plates, which makes the robot very easy to make. Q-Whex is capable of performing wheeled-like smooth rides over flat ground with a tripod gait, and thereby prevent the common problem of trunk fluctuations in legged-wheel robots. It is also able to traverse height variations well exceeding its trunk clearance. The performance of Q-Whex is evaluated in various scenarios, including driving and turning over flat terrains, ramp-riding, step-crossing, stair-climbing, and irregular terrain-traversing. K E Y W O R D S hexapod robot, legged locomotion, quasi-wheel, wheeled-like smooth ride
... Some of these replacement wheels combine multiple smaller wheels into one larger wheeled assembly [19][20][21]. Specifically, in the case of replacement parts, both the rear and front wheels [22][23][24][25] have been considered for replacement, and the use of crawlers [26][27][28][29], instead of wheels, has also been investigated. In addition, some devices have been designed for stair ascending from inception. ...
Obstacles such as ramps, steps, and irregular floor surfaces are commonly encountered in homes, offices, and other public spaces. These obstacles frequently limit the daily activities of people who use mobility aids. For this purpose, this study solves a slope minimization problem for personal mobility aids. As a solution approach, a gradient-reduction scheme is proposed, which allows existing mobility aids to reduce the required horizontal forces and vibrations when ascending steps while maintaining their wheel sizes. Practically, an axle-transitional wheel mechanism realizing the gradient-reduction computation model is established, and its step-ascending wheel prototype is developed. Specifically, since the proposed wheel enables integration into existing personal mobility-assisting devices, two functional roles, such as rolling and step ascending, can be used. The developed step-climbing wheel can help the users of mobility aids mitigate the aforementioned limitations. The physical and mental burdens of caregivers and medical staff can also be reduced by making the users of the gradient-reduction scheme more self-sufficient. This study provides details on the axle-transitional wheel mechanism and its step-ascending wheel prototype. The findings are analyzed mathematically, and their functionality is verified through extensive experiments using a prototype.
... Different spoke wheels have various shapes and different numbers of spokes. For example, TERMES [22], Mini-Whegs [23], and Loper [24] all adopted spoke wheels with three spokes whose shapes are different. The spoke wheels of USAR Whegs [25] had four spokes, while the ones of ASGUARD [26] had five spokes. ...
In this paper, a novel transformable leg-wheel mechanism is proposed. It has three active joints, among which the hip roll joint is directly driven, the hip pitch joint is driven by gear transmission, and the knee joint is driven by synchronous belt transmission. All the actuators are mounted on the body to reduce the weight of the leg-wheel mechanism as possible, so that the motion of the leg-wheel mechanism will be slightly affected by the inertia. The proposed mechanism has two characteristics, big wheel radius and reduced actuators. The design and kinematics modeling methods of the leg-wheel mechanism are described. A half-a-heart shape trajectory is proposed to plan the foot motion of the leg-wheel mechanism in the legged locomotion. To make the locomotion mode transition smooth, the transition strategy is designed. Simulation and experimental results verify the feasibility of the proposed leg-wheel mechanism.
... In addition, there is the problem of discrete motion [16]. The tri-wheel mechanism [17] is a structure that provides stable motion by a tri-wheel. However, it cannot be used effectively for stairs with varying sizes. ...
This paper proposes a mobile robotic platform, LEVO, which uses a normal wheel and a curved-spoke tri-wheel (CSTW). The normal wheel is used for driving on flat terrain, and the CSTW is used for stair climbing. In order to use the two mechanisms independently, a switching mechanism that consists of ball screw, linear motion guide, and actuator is added. Therefore, the proposed robot can be driven in both wheel mode and CSTW mode. The CSTW mode is implemented by lowering the CSTW to the ground and raising the rear wheels (caster), while the wheel mode is implemented by lowering caster to the ground and raising the CSTW. In order to design the switching mechanism and CSTW mechanism, static and kinematic analyses are performed. Further, a prototype is assembled to verify the mode-switching, stair climbing, and wheel-driving functions. The experiment was repeated on stairs with different sizes and materials. The results show that robots can drive on both flat terrain and stairs. Therefore, the proposed robot is expected to be useful as a mobile robot platform suitable for indoor environments.
... The sixth, rotating wheeled leg robot. These kinds of robot locomote with rotating wheeled shape legs or arms, which is a suitable solution for small size robots to reduce the complexity of the control system, while preserving good obstacle climbing ability, such as the Loper [48], RHex [49], and ASGUARD [50]. But robots with rotating legs are constantly subjected to shocks and vibrations in the process of movement, which is not conducive to them to carry mission equipment such as cameras. ...
Mobile robots can replace rescuers in rescue and detection missions in complex and unstructured environments and draw the interest of many researchers. This paper presents a novel six-wheeled mobile robot with a reconfigurable body and self-adaptable obstacle-climbing mechanisms, which can reconfigure itself to three locomotion states to realize the advantages of terrain adaptability, obstacle crossing ability and portability. Design criteria and mechanical design of the proposed mobile robot are firstly presented, based on which the geometry of the robot is modelled and the geometric constraint, static conditions and motion stability condition for obstacle crossing of the robot are derived and formulated. Numerical simulations are then conducted to verify the geometric passing capability, static passing capability and motion stability and find feasible structure parameters of the robot in obstacle crossing. Further, a physical prototype of the proposed mobile robot is developed and integrated with mechatronic systems and remote control. Using the prototype, field experiments are carried out to verify the feasibility of the proposed design and theoretical derivations. The results show that the proposed mobile robot satisfies all the criteria set and is feasible for applications in disastrous rescuing scenarios.
... Locomotion with rotating legs or arms is a suitable solution for small-sized robots to reduce the complexity of the control system while preserving good obstacle-climbing ability, such as the Loper (Herbert et al., 2008), RHex (Altendorfer et al., 2001), and ASGUARD (Waldron et al., 2009). But robots with rotating legs are constantly subjected to shocks and vibrations in the process of movement, which is not conducive to them carrying mission equipment such as cameras. ...
A six-wheeled companion exploration robot with an adaptive climbing mechanism is proposed and released for the complicated terrain environment of planetary exploration. Benefiting from its three-rocker-arm structure, the robot can adapt to complex terrain with its six wheels in contact with the ground during locomotion, which improves the stability of the robot. When the robot moves on the flat ground, it moves forward through the rotation of the wheels. When it encounters obstacles in the process of moving forward, the front obstacle-crossing wheels hold the obstacle, and the rocker arms on both sides rotate themselves with mechanical adaptivity to drive the robot to climb and cross the obstacle like crab legs. Furthermore, a parameterized geometric model is established to analyze the motion stability and the obstacle-crossing performance of the robot. To investigate the feasibility and correctness of design theory and robot scheme, a group of design parameters of the robot are determined. A prototype of the robot is developed, and the experiment results show that the robot can maintain stability in rugged terrain environments and has a certain ability to surmount obstacles.
... Further efforts with no circular wheels but with only legs have been done [10], [11], [16]. Further improvement has been done with no wheels but with only blade wheels which can be folded manually for easier transportation of robot [12]. ...
Future planetary exploration missions will require mobile robots which are able to carry out highperformance locomotion tasks. The robotic platform should be able to move between areas of interest quickly and safely. Improvement of robotics and or robotic movement is a continuing pursuit. Wheeled transportation can be characterized by greater efficiency or speed, while articulated leg transportation can be characterized by greater flexibility for movement over complex terrain. Wheels can rotate quickly, but can have difficulty on uneven terrain, while articulated legs can negotiate the uneven terrain, but can have difficulty with speed. Such wheeled transport can have limited mobility and behavior due to complex environment and lack of adaptability to unpredictable terrain. There exists now an interest for a new type of vehicle which inherits both advantages of legged and wheeled vehicles, namely the high adaptive capabilities of legs and the high velocity and payload of the wheels. In order to deal with the rough terrains of planetary surfaces, researchers put most of the efforts in designing new structure of rover body, but give less attention to new types of reconfigurable mechanism for wheels and trailing link (utilized in two wheeled robots).
In this paper,“Singrauli 1.0”, a novel reconfigurable mechanism for “Elan Robot”, is proposed. This reconfigurable mechanism combines two elementary mechanisms. One is responsible for expanding the wheel and the other one for ensuring sufficient elongation of trailing link to maintain the stability of the robotic platform while encountering uneven terrains and negotiating stairs. This proposed reconfigurable mechanism “Singrauli 1.0”, is a single degree of freedom mechanism. Reconfigurability enhances mobility capability in different terrains. “Elan Robot”, utilizes perfect circular form as wheel with conventional width for travelling over even surfaces and also utilizes expandable wheel form for travelling over uneven surfaces. Proposed Elan Robot can move steadily and turn around agilely. Thanks to its novel reconfigurable mechanism which enhances the locomotion performance and enable robot to climb steps or hurdles whose height is almost four times higher than the radius of the robot’s wheel. And, there is no resistance in between wheel tracks while expanding the wheel diameter.
... Dalvand designed a wheeled mobile robot that has the capability of climbing stairs, traversing obstacles [9]. Herbert designed a Tri-lobe wheel [10]. This paper aims to implement a quadruped robot to climb two or three stairs in one single step with long legs while maintaining stability. ...
... e wheel-leg structure can complete the three types of obstacle crossing, and the frame always runs horizontally. e wheel-leg robot has good road profile and ability to cross obstacles [23,24]. ...
Due to its special topographical structure, the forest working environment requires a vehicle chassis that can adapt well to complex terrain conditions. This article describes the key components of a chassis that was designed to adapt to complex terrain. The working principle and structural design of the steering structure and the lifting structure are analyzed in detail, and function verification is carried out. The steering mechanism has three degrees of freedom, and the first degree of freedom reduces the body’s inclination by 30°. The second degree of freedom can increase the steering angle of the chassis to 47°, decreasing the turning radius of the chassis. The third degree of freedom reduces the body rollover inclination by 30°. The entire steering mechanism enhances the ride and stability of the chassis. With the lifting mechanism, the wheel-legs are lifted so that the chassis can pass a limit height of 187 mm, and the wheel-legs are lowered to raise the center of gravity of the vehicle chassis by 244 mm. The entire lifting mechanism greatly improves the vehicle's ability to cross forest terrain. The size is reduced by 10% compared to other structures, and the lifting height and obstacle resistance are improved by 12.7%.
... These are the wheels from which the wheelsused in this robot have been derived, according to the requirement. Fig. 3. Loper Wheels [7] It was observed that Loper wheels would be easier to manufacture and economic as well. So prototyping was performed with a three loped loper wheel. ...
Automation is one of the trending subjects surrounding the manufacturing industry in the 21st century. Not only does it help manufacturers keep up with growing global demand, it also helps create new job opportunities as well as help a manufacturer progress into the 21st century. With the advancement of technology, robots are getting more attention of researchers to make life of mankind comfortable. This paper discusses the design of prototype of Automatic Classroom Vacuuming Robot (using User Interface Elements in Power Control of Electronic Devices employed in Office/Consumer Environments). The robot works autonomously within a confined space (in this case classroom) and requires human intervention only to transfer it from one class to another. The robot is designed to replace human efforts with automation and can be a radical technology if made affordable.
... The solution proposed by the authors in this paper is not a new one. The speciality literature reports several achievements regarding this type of locomotion unit which is referred to as a Tri-Star wheel [4], [5], [6], [7], [8], [9], [10], [11], [12], [13]. ...
The first part of the paper presents a short introduction into the hybrid robots field and a classification for the wheel-leg hybrid robots. The second part presents the design and functionality of the locomotion unit proposed by the authors and the last part details the development paths proposed by the authors for this locomotion unit.
... Some examples of stair climbing robots include the Shrimp Rover [1], which has a clever mechanism design that combines wheels and self-adjustable linkages to maintain suitable body posture and increase its mobility on uneven terrains and stairs. Similarly, Loper [2] climbs stairs by rotating four Tri-lobe wheels. IMPASS [3] climbs obstacles using two rimless spoke wheels with two degrees of freedoms(DOFs). ...
... Moreover, if the robot is small and lightweight, the inertial forces acting during locomotion are less critical than for large and heavy robots; therefore, if legged locomotion is adopted, simplified hybrid locomotion mechanisms can be used, leveraging on the advantages of legs while avoiding the high mechanical and control complexity of large legged robots (such as bipeds and quadrupeds). Some examples of this approach are stepping-triple-wheel robots [10][11][12], rotating legged robots [13][14][15], robots with legs with outer circular profile, which can act as wheels [16][17][18]. ...
The paper presents the third version of the hybrid leg-wheel ground mobile robot Mantis, a small-scale platform designed for inspection and surveillance tasks. The locomotion system is based on the cooperating action of a couple of actuated front legs and wheels, along with a passive rear carriage. The system performs wheeled locomotion on even grounds and hybrid locomotion in case of terrain irregularities or obstacles. This architecture combines high speed, energy efficiency, maneuverability and stable camera vision on flat terrains with good motion capabilities in unstructured environments. In the embodiment design presented hereafter, referred to as Mantis 3.0, the rear carriage has been equipped with four passive wheels, instead of two as in the previous versions, in order to improve the stability during steep stair climbing maneuvers; moreover, the legs, the main body and the rear carriage have been significantly redesigned in order to be realized by additive manufacturing techniques, with the final aim of obtaining a low-cost device suitable for Open Source distribution.
... Moreover, if the robot is small and lightweight, the inertial forces acting during locomotion are less critical than for large and heavy robots; therefore, if legged locomotion is adopted, simplified hybrid locomotion mechanisms can be used, leveraging on the advantages of legs while avoiding the high mechanical and control complexity of large legged robots (such as bipeds and quadrupeds). Some examples of this approach are stepping-triple-wheel robots [10][11][12], rotating legged robots [13][14][15], robots with legs with outer circular profile, which can act as wheels [16][17][18]. ...
The paper presents the third version of the hybrid leg-wheel ground mobile robot Mantis, a small-scale platform designed for inspection and surveillance tasks. The locomotion system is based on the cooperating action of a couple of actuated front legs and wheels, along with a passive rear carriage. The system performs wheeled locomotion on even grounds and hybrid locomotion in case of terrain irregularities or obstacles. This architecture combines high speed, energetic efficiency, maneuverability and stable camera vision on flat terrains with good motion capabilities in unstructured environments. For what concerns the embodiment design presented hereafter, referred to as Mantis 3.0, the rear carriage has been equipped with four passive wheels, instead of two as in the previous versions, in order to improve the stability during steep stair climbing maneuvers; moreover, the legs, the main body and the rear carriage have been deeply redesigned in order to be realized by additive manufacturing techniques, with the final aim of obtaining a low-cost device suitable for Open Source distribution.
... One viable approach to overcome this bottleneck is to design a next generation cleaning robots that are able to reconfigure themselves between floor and staircase cleaning modes, thereby, maximizing their dexterous task performance. A number of design mechanisms towards realizing staircase climbing robots have been proposed and validated [14][15][16][17][18]. However, these robots target mostly search, rescue and security applications using design principles and mechanisms that are not optimal for cleaning tasks. ...
In this article, the mechanical, electrical and autonomy aspects of designing a novel, modular and reconfigurable cleaning robot, dubbed as sTetro (stair Tetro), are presented. The developed robotic platform uses a vertical conveyor mechanism to reconfigure itself and is capable of navigating over flat surfaces as well as staircases, thus significantly extending the automated cleaning capabilities as compared to conventional home cleaning robots. The mechanical design and system architecture are introduced first, followed by a detailed description of system modelling and controller design efforts in sTetro. An autonomy algorithm also proposed for self-reconfiguration, locomotion and autonomous navigation of sTetro in the controlled environment, e.g. in homes/offices with flat floor and straight staircase. A staircase recognition algorithm is presented to distinguish between surrounding environment and the stairs. The misalignment detection technique of the robot with front staircase riser is also given and a feedback from IMU sensor for misalignment corrective measures is provided. The Experiments performed with the sTetro robot demonstrated the efficacy and validity of the developed system models, control and autonomy approaches.
... A number of solutions exist for this design; for example, two wheels on a turnable arm are used by the robotic wheelchair 12 ; the principle of the two wheels on the flipped carrier is also used for stairclimbing in Wang et al. 13 ; a variant of the known Segway principle with pairs of wheels on each side is used by the powered wheelchair iBot. 14 Three wheels on a carrier have been known as the wheel cluster, Weinstein-wheel or tri-star wheel concept; the Loper robot undercarriage 15 can be mentioned as an example. The four wheels on a shared carrier are also the subject of a patented solution. ...
The article describes the process of development of an essentially new wheel suitable both for moving on flat ground and for travelling on stairs. The stair-climbing wheel is composed of rotary circular segments arranged around a shared carrier with arms to form a complete circular profile of the wheel adapted for moving on flat ground; for travelling on stairs, individual segments are rotated by an appropriate angle to touch down tangentially on the stepping surface of the stairs. The dimensions of individual segments, the centre of rotation of individual segments and the angle of their partial turn have been chosen so that the length of the arc along which the circular segment rolls is equal to the length of the stepping surface of an average stair, and, at the same time, the circular segment touches down tangentially on the stepping surface while the wheel turns around the edge of the previous segment. Using the rotation angle of the turnable segments, the wheel can be adapted to the height of non-standard stairs. The segments can be inclined in both directions for bidirectional movement of the wheel up and down the stairs. An undercarriage equipped with these wheels can be used in the field of exploratory robots and for the transportation of persons and materials on stairs.
... The notched wheel model [11] can be used to easily calculate the climbing performance. This model can generalize previous special wheel shapes such as that of Tri-Lobe [12], with three small wheels mounted on a central hub, the CLOVER wheel [13] which resembles a gear and was designed for coping with volcanic environments, and a rimless-type wheel [14] [15] with multiple spokes. The model is simplified and does not include dynamics because the motion of the robot is slow, but is easy to calculate by using geometry. ...
... Whegs series [26] and IMPASS [27] are two typical robots with such mechanisms. Although the leg-wheel mechanisms of Loper [28] and ASGUARD [29] seem to be different from the spoke wheel, they are similar in function. The other kind of coupled leg-wheel mechanism is the transformable leg-wheel, which can change between the legged and wheeled structures according to the terrain. ...
In this paper, the design and implementation of a novel leg-wheel robot called Transleg are presented. Transleg adopts the wire as the transmission mechanism to simplify the structure and reduce the weight. To the best knowledge of the authors, the wire-driven method has never been used in the leg-wheel robots, so it makes Transleg distinguished from the existing leg-wheel robots. Transleg possesses four transformable leg-wheel mechanisms, each of which has two active degrees-of-freedom (DOFs) in the legged mode and one in the wheeled mode. Two actuators driving each leg-wheel mechanism are mounted on the body, so the weight of the leg-wheel mechanism is reduced as far as possible, which contributes to improving the stability of the legged locomotion. Inspired by the quadruped mammals, a compliant spine mechanism is designed for Transleg. The spine mechanism is also actuated by two actuators to bend in the yaw and pitch directions. It will be beneficial to the turning motion in the legged and wheeled modes and the bounding gait in the legged mode. The design and kinematic analyses of the leg-wheel and spine mechanisms are presented in detail. To verify the feasibility of Transleg, a prototype is implemented. The experiments on the motions in the legged and wheeled modes, the switch between the two modes, and the spine motions are conducted. The experimental results demonstrate the validity of Transleg.
... On the contrary, for small-scale robots, the inertial forces are less critical, and simplified hybrid locomotion mechanisms can be adopted, conjugating the benefits of legs and wheels without significantly increasing the complexity and costs. Examples are rotating legged robots [13][14][15] and stepping-triple-wheel robots [16][17][18], characterized by locomotion units with three legs placed at 120 • , with a wheel at each end. Another approach to implement hybrid leg-wheel locomotion is the adoption of legs with outer circular profile, which can act as wheels when properly coordinated [19][20][21]. ...
Mantis 2 is a small-scale leg-wheel ground mobile robot, designed for exploration, surveillance and inspection tasks in unstructured environments. It is equipped with two actuated front wheels, two passive rear wheels, and two rotating legs with praying Mantis profile, specially conceived for step and obstacle climbing. Locomotion is purely wheeled on regular surfaces, with high energetic efficiency and maneuverability, and with stable camera vision. In case of obstacles or terrain irregularities, the rotating legs increase the motion capability. The main innovation of the second version is the introduction of passive one-way auxiliary wheels on each leg, which improve the efficacy of step climbing. The paper discusses analytical and experimental results on step ascent and descent and locomotion on irregular surfaces.
The disabled usually utilize wheelchairs for their daily mobility and locomotion. These motorized vehicles can travel on relatively flat surfaces or tracks without any problems, but moving up and down the stairs is always a challenge for most commercial wheelchairs. In other words, a person with a disability cannot go anywhere inside a multi-story building, shopping store, subway, etc. if they are not built according to accessibility codes. This article proposes two novel designs to facilitate the stair-climbing feature for a motorized wheelchair. One of the design concepts is based on a curved-spoke mechanism with transformation capability from a round wheel to a tri-leg mechanism to facilitate the translation mode as well as the stair-climbing mode of a wheelchair. The next design concept is an enhanced tri-wheel mechanism using a combination of a tri-wheel setup and planetary gears, to provide a unique capability for the climbing mechanism. After analysis and considering the pros and cons of each design concept, the tri-wheel planetary mechanism has been selected for making a scaled-down model and testing the transmission system on the stairs. The scaled-down prototype can successfully move up or down the stairs in the climbing mode and travel on flat or inclined surfaces in the translation mode.
This paper introduces a novel design and static optimization for a two-degrees-of-freedom transformable wheel based on a geared linkage mechanism. Overcoming obstacles, including stairs, with small wheels is a major challenge in the field of mobile robotics research. Among various robots, the transformable wheel, which can change the shape of the wheel to overcome steps and optimize the path, was presented and has undergone many improvements. Nevertheless, problems such as asymmetry and structural strength remain. Therefore, the design of this paper aims to address the structural inefficiencies identified in the previous research model, which were attributed to the asymmetric placement of the linear motion guide. Through the implementation of this mechanism, the linear motion of the lobe can be segregated, enabling each input motor to share the workload effectively. The optimization process focus on determining the optimal linkage length under static conditions, resulting in improved structural characteristics and force distribution of linkage within the designated workspace. As a result, asymmetry of motion is eliminated, required intervention angle of the driving motor and stress of linkage was reduced by 36.24% and 8.35%, respectively.
Tensegrity structures made from rigid rods and elastic cables have unique characteristics, such as being lightweight, easy to fabricate, and high load-carrying to weight capacity. In this article, we leverage tensegrity structures as wheels for a mobile robot that can actively change its shape by expanding or collapsing the wheels. Besides the shape-changing capability, using tensegrity as wheels offers several advantages over traditional wheels of similar sizes, such as a shock-absorbing capability without added mass since tensegrity wheels are both lightweight and highly compliant. We show that a robot with two icosahedron tensegrity wheels can reduce its width from 400 to 180 mm, and simultaneously, increase its height from 75 to 95 mm by changing the expanded tensegrity wheels to collapsed disk-like ones. The tensegrity wheels enable the robot to overcome steps with heights up to 110 and 150 mm with the expanded and collapsed configuration, respectively. We establish design guidelines for robots with tensegrity wheels by analyzing the maximum step height that can be overcome by the robot and the force required to collapse the wheel. The robot can also jump onto obstacles up to 300-mm high with a bistable mechanism that can gradually store but quickly release energy. We demonstrate the robot's locomotion capability in indoor and outdoor environments, including various natural terrains, like sand, grass, rocks, ice, and snow. Our results suggest that using tensegrity structures as wheels for mobile robots can enhance their capability to overcome obstacles, traverse challenging terrains, and survive falls from heights. When combined with other locomotion modes (e.g., jumping), such shape-changing robots can have broad applications for search-and-rescue after disasters or surveillance and monitoring in unstructured environments.
One drawback of wheeled robots is hard to conquer large obstacles and perform well on complicated terrains, which limits its application in rescue missions. To provide a solution to this issue, an ant-like six-wheeled reconfigurable robot, called AntiBot, is proposed in this paper, which employs a Sarrus reconfiguration body, a three-rocker-leg passive suspension and mechanical adaptable obstacle-climbing wheeled-legs. In this paper, we demonstrate through simulations and experiments that this robot can change the position of its centre of mass actively to improve its obstacle crossing capability. The geometric and static stability conditions for obstacle crossing of the robot are derived and formulated, and numerical simulations are conducted to find the feasible region of the robot's configuration in obstacle crossing. In addition, a self-adaptive obstacle crossing algorithm is proposed to improve the robot's obstacle crossing performance. A physical prototype is developed, and based on which a series of experiments are carried out to verify the effectiveness of the proposed self-adaptive obstacle crossing algorithm.
This paper presents the design optimization of a linkage-based wheel mechanism with two degrees of freedom, for stable step climbing. The mechanism has seven rotational joints and one prismatic joint. Kinematic and dynamic analyses of the mechanism were performed. The design was optimized in terms of linkage length and architecture to better manipulate the mechanism in its workspace, which was defined here by the targeted step size, as well as to ensure stability while climbing stairs. Optimization by genetic algorithm was performed using MATLAB. The optimized mechanism exhibited enhanced torque transmission from the input torque to the exerted for at the lobe of the wheel. Compliance control of the transformation will be addressed in the future.
The effectiveness of exploration robots is contingent upon their capability and efficiency to locomote on contorted and multifaceted terrains. Traditional wheeled robots do not suffice at overcoming such terrains and complications they introduce. The proposed work explores the performance of WhegRunner, a whegged (i.e., wheel‐legged) robotic platform used to examine the mechanics of running on granular media at different saturation levels. In particular, the effect of bipedal/quadrupedal gait, saturation level, stride length, and stride frequency on robot's forward body velocity and cost of transport (COT) was studied. To increment nominal stride length, the robot was fitted with different number of spoked whegs from 3 to 7. In addition, eight evenly spaced motor speeds ranging from 2.33 to 7.43 Hz were used to observe the effect of stride frequency. Similar trends were observed between the two gaits, with the quadrupedal gait showing better overall performance. On dry sand, wider strides were attained at reduced motor speeds with lower spoked whegs. However, on wet sand (15% and 30% saturation), wider strides were achieved with higher motor speeds and lower spoked whegs. As a result, lower spoked whegs accomplished higher body forward velocity and lower COT as saturation increased. The acquired knowledge elucidates underexplored mechanics of locomotion on granular media at different saturation levels. The WhegRunner can be used as a platform to obtain a greater insight on how to develop more proficient exploration robots, ones which can face complex and deformable terrains and mediums.
This paper highlights the main functional features of the first prototype of WheTLHLoc, a hybrid leg-wheel-track ground mobile robot. WheTLHLoc is conceived as a general-purpose surveillance and inspection platform, which combines several distinctive features: tracked locomotion on irregular and/or yielding grounds, high efficiency wheeled locomotion on flat and compact terrains, step/stairs climbing and descent ability to allow motion in structured and unstructured environments. The architecture of the hybrid locomotion system is outlined, then the internal mechanical arrangement and the actuation and control layout are discussed.KeywordsGround mobile robotHybrid locomotionStep climbingStair climbingSurveillanceInspection
To realize intelligent express delivery and unmanned automatic transportation in different environments and terrains, this paper proposes an alternate wheel-leg transport robot (AWLBOT). First, this article combines the knowledge in the field of biomimetic robot design, uses a modular design to divide the basic functions of the transportation robot into independent unit modules. Focus on the statics analysis and modal analysis of the robot support legs and the fuselage frame, verifying the rationality of the structural design and material selection. The stability analysis of the robot based on the climbing environment verifies the rationality of the robot's gait planning and the accuracy of the motion analysis. Finally, the robot designed in this paper has good flexibility, stability, and safety by comparing it with the existing ones.
Soft Robotics offers an opportunity to fabricate more adapt-
able systems to be used outside industrial areas. For practical applications of soft robots, their active parts should achieve high forces and considerable displacements, keeping the structures lightweight, modular, and easy to fabricate. Consequently, robust and predictable motion actuators with easy manufacture are required. This paper applies the origami concept to address a 3D printed low-weight modular soft pneumatic linear actuator denoted ORI-Structure. The presented structure has a high
contraction rate (up to 52.5%) and can lift 1161.64x its weight. Additionally, we present a more complex module with 3 DOF formed with the ORI-Structure. The module can displace linearly with a high-contraction rate (up to 52.5%), and it can rotate in two axes up to 42°. In both cases, the module exhibits high-lifting capabilities (611.53x its weight). In both cases, simulation and experiments are introduced to describe the design parameters and their performances.
This paper presents the dynamic modeling and analysis of an inverted pendulum robot with an adaptable overcoming wheel. Stairways are inevitable in environments where humans and robots operate and interact. The conventional wheel cannot overcome an obstacle that is higher than the radius of the wheel of the inverted pendulum robot. This paper presents a solution for a problematic situation in which a balancing robot climbs steps with a pair of transformable wheels. Dynamic modeling of the varying radius of the wheel was performed using the Lagrangian approach, and a simple gain controller was selected. Simulations were carried out using MATLAB and Simulink to confirm the dynamic model. In future work, the wheel should be tested on a robot model.
The ability of wheeled mobile robots to overcome steps is often limited by wheel size. Enhancing the ability of mobile robots to overcome obstacles is essential for extending their operation area, and many previous attempts have been made by using transformable wheels, a linkage mechanism, and a spoke-type wheel-leg mechanism. In this study, we propose a shape-morphing wheel mechanism for step climbing at high speed. In the general case of low speed locomotion, a robot's wheels can be used normally. However, to overcome relatively large obstacles, the robot's wheels can extend its shape by using the proposed morphing mechanism with centrifugal force at high speed locomotion. Two modes of step climbing are analyzed that use kinetic energy conversion or impact on the steps. Detail design issues with comprehensive analyses results are presented. Results demonstrate that a robot with morphing wheels can climb a 46.67 mm obstacle at 1.82 m/s, which is 1.33 times larger than the wheel radius. We expect that this method can be applied to other locomotion modes of wheeled mobile robots.
In this study, the control of a two-wheeled stair-climbing inverted pendulum robot and its climbing motion are analyzed and discussed. The robot adopts a state-feedback controller with a feed-forward constant to stabilize the body and achieve step-climbing motion. The control parameter is considered based on the dynamic model motion on a flat surface and the static model of motion on the step. For climbing stairs with a narrow step tread, a constant torque is applied to reduce the space required for recovering the body stability after climbing. The stability of the robot is numerically analyzed by analyzing the orbital stability of its limit cycle. The stability analysis shows that the control method can achieve a stable stair-climbing motion. The effectiveness of the control method is demonstrated through an experiment. The result indicates that the robot can climb the stairs, and the required time for climbing a single step is approximately 1.8 s.
Stairs are common obstacles in indoor environments and are difficult to overcome for robots. The speed of robot stair-climbing should be similar to that of humans for commercial products, but their speed remains limited. Additionally, the variety of dimensions of stairs is also a significant problem for robust stair-climbing by robots. In this paper, a curved spoke-based tri-wheel mechanism is proposed for fast and robust stair-climbing. The goal speed of stair-climbing is similar to the human speed for variously sized stairs. The proposed wheel system is composed of a tri-wheel mechanism with a curved spoke, wherein the dimensions of the mechanism are determined based on a kinematic analysis. Between the tri-wheels, a stopper mechanism acts to make the initial condition of the sequential stair-climbing the same as the initial starting condition. Static analysis to analyze the minimum friction coefficient is performed to verify the performance of the robot. Experiments based on the prototype are performed to verify the stair-climbing speed for variously sized stairs; the results indicate that fast and robust stair climbing performance is achieved. These findings can be used to design an indoor service robot for various applications.
Automating the double-hull block welding improves the shipbuilding efficiency and mitigates health risk to the welders. Due to the unique challenge posed by the internal structures, existing technologies are at most semi-autonomous. Believing that mobility is key to full autonomy, we employ mobile robot technology to transport the welding manipulator, treating the internal structures as obstacles. Though many robot designs for obstacle scaling exist, there is no selection guideline. To this end, we surveyed existing robots and came out with a taxonomy to explain the design philosophies behind them. From the survey, it is ascertained that there are two suitable philosophies: bridging and conforming. Bridging mechanisms create links between points on obstacles while conforming mechanisms have the robot’s body attuned to the surface contour of obstacles. Understanding the pros and cons, we conclude that having a hybrid mechanism with tracked arms and articulated body would be ideal for the structured environment. Subsequently, we studied the feasibility of the design in terms of configuration, geometry, kinematics, and stability. Lastly, the proposed design was tested by building a 1/3 scale prototype robot. It was made to perform the expected motions in a mock double-hull block setup. The experiment proved that the design achieves the mobility objectives of the robot. With this mobility design, we solved the most challenging issue in enabling fully autonomous welding in double-hull blocks. The taxonomy is instrumental in our design selection and could be helpful for other robot designers too.
This paper presents a novel strategy for designing passively-adaptive, statically-stable walking robots with full body mobility that are exactly-constrained and non-redundantly actuated during stance. In general, fully-mobile legged robots include a large number of actuated joints, giving them a wide range of controllable foot placements but resulting in over-constraint during stance, requiring kinematic redundancy and redundant control for effective locomotion. The proposed design strategy allows for the elimination of actuation redundancy, thus greatly reducing the weight and complexity of the legged robots obtained and allowing for simpler control schemes. Moreover, the under-constrained nature of the resulting robots during swing allows for passive adaptability to rough terrain without large contact forces. The strategy uses kinematic mobility analysis tools to synthesize leg topologies, underactuated robotics design approaches to effectively distribute actuation constraints, and elastic elements to influence nominal leg behavior. Several examples of legged robot designs using the suggested approach are thoroughly discussed and a proof-of-concept of a non-redundant walking robot is presented.
We present the first controller that allows our small hexapod robot, RHex, to descend a wide variety of regular sized, "real world" stairs. After selecting one of two sets of trajectories, depending on the slope of the stairs, our open-loop, clock-driven controllers require no further operator input nor task level feedback. Energetics for stair descent is captured via specific resistance values and compared to stair ascent and other behaviors. Even though the algorithms developed and validated in this paper were developed for a particular robot, the basic motion strategies, and the phase relationships between the contralateral leg pairs are likely applicable to other hexapod robots of similar size as well.
The capability of autonomous and semi-autonomous platforms to function in the shallow water surf zone is critical for a wide range of military and civilian operations. Of particular importance is the ability to transition between locomotion modes in aquatic and terrestrial settings. The study of animal locomotion mechanisms can provide specific inspiration to address these demands. In this work, we summarize on-going efforts to create an autonomous, highly mobile amphibious robot. A water-resistant amphibious prototype design, based on the biologically-inspired Whegstrade platform, has been completed. Through extensive field-testing, mechanisms have been isolated to improve the implementation of the Whegstrade concept and make it more suited for amphibious operation. Specific design improvements include wheel-leg propellers enabling swimming locomotion, an active, compliant, water resistant, non-backdrivable body joint, and improved feet for advanced mobility. These design innovations allow Whegstrade to navigate on rough terrain and underwater, and accomplish tasks with little or no low-level control, thus greatly simplifying autonomous control system implementation. Complementary work is underway for autonomous control. We believe these results can lay the foundation for the development of a generation of amphibious robots with an unprecedented versatility and mobility
Portable mobile robots, in the size class of 20 kg or less, could be extremely valuable as autonomous reconnaissance platforms in urban hostage situations and disaster relief. We have developed a prototype urban robot on a novel chassis with articulated tracks that enable stair climbing and scrambling over rubble. Autonomous navigation capabilities of the robot include stereo vision-based obstacle avoidance, visual servoing to user-designated goals, and autonomous vision-guided stair climbing. The system was demonstrated in an urban reconnaissance mission scenario at Fort Sam Houston in October 1999. A two-axis scanning laser rangefinder has been developed and integrated into the robot for indoor mapping and position estimation. This paper describes the robot, its performance in field trials, and some of the technical challenges that remain to enable fieldable urban reconnaissance robots.
This paper describes novel highly mobile small robots called "mini-whegs" that can run and jump. They are derived from our larger whegs series of robots, which benefit from abstracted cockroach locomotion principles. Key to their success are the three spoked appendages, called "whegs", which combine the speed and simplicity of wheels with the climbing mobility of legs. To be more compact than the larger whegs vehicles, mini-whegs uses four whegs in an alternating diagonal gait. These 9 cm long robots can run at sustained speeds of over 10 body lengths per second and climb obstacles that are taller than their leg length. They can run forward and backward, on either side. Their robust construction allows them to tumble down a flight of stairs with no damage and carry a payload equal to twice their weight. A jumping mechanism has also been developed that enables mini-whegs to surmount much larger obstacles, such as stair steps.
Applying abstracted biological locomotion principles with reduced actuation can result in an energetic vehicle with greater mobility because a vehicle with the fewest number of motors can have the highest power to mass ratio. One such hexapod is Whegs II, which benefits from abstracted cockroach locomotion principles and has just one motor for propulsion. Similar to Whegs I, it nominally runs in a tripod gait and passive mechanisms enable it to adapt its gait to the terrain. One of the drawbacks of Whegs I is that it cannot change its body posture. Cockroaches pitch their bodies up in anticipation of climbing a step to enable their front legs to reach higher. They also flex their bodies down while climbing to permit their front legs to maintain contact with the substrate. A bidirectional servo-driven body flexion joint has been implemented in Whegs II to accomplish both of these behaviors. It is shown to be highly mobile and energetic.
We present the system overview and integration of the ASIMO autonomous robot that can function successfully in indoor environments. The first model of ASIMO is already being leased to companies for receptionist work. In this paper, we describe the new capabilities that we have added to ASIMO. We explain the structure of the robot system for intelligence, integrated subsystems on its body, and their new functions. We describe the behavior-based planning architecture on ASIMO and its vision and auditory system. We describe its gesture recognition system, human interaction and task performance. We also discuss the external online database system that can be accessed using internet to retrieve desired information, the management system for receptionist work, and various function demonstrations.
Search and rescue operations in large disaster sites require quick gathering of relevant information. Both the knowledge of the location of victims and the environmental/structural conditions must be available to safely and efficiently guide rescue personnel. A major hurdle for robots in such scenarios is stairs. A system for autonomous surmounting of stairs is proposed in which a Scout robot jumps from step to step. The robot's height is only about a quarter step in size. Control of the Scout is accomplished using visual servoing. An external observer such as another robot is brought into the control loop to provide the Scout with an estimation of its pose with respect to the stairs. This cooperation is necessary as the Scout must refrain from ill-fated motions that may lead it back down to where it started its ascend. Initial experimental results are presented along with a discussion of the issues involved.
RHex is a hexapod with compliant legs and only six actuated
degrees of freedom. Its ability to traverse highly fractured and
unstable terrain, as well ascend and descend a particular flight of
stairs has already been documented. In this paper, we describe an open
loop controller that enables our small robot (length: 51 cm, width: 20
cm, height: 12.7 cm, leg length: 16 cm) to reliably climb a wide range
of regular, full-size stairs with no operator input during stair
climbing. Experimental data of energy efficiency in a form of specific
resistance during stair climbing is given. The results presented in this
paper are based on a new half circle leg design that implements a
passive, effective leg length change
Successful distributed sensing and control require data to flow
effectively between sensors, processors and actuators on single robots,
in groups and across the Internet. We propose a mechanism for achieving
this flow that we have found to be powerful and easy to use; we call it
Player. Player combines an efficient message protocol with a simple
device model. It is implemented as a multithreaded TCP socket server
that provides transparent network access to a collection of sensors and
actuators, often comprising a robot. The socket abstraction enables
platform- and language-independent control of these devices, allowing
the system designer to use the best tool for the task at hand Player is
freely available from http://robotics.usc.edu/player
In this paper, the authors describe the design and control of RHex, a power autonomous, untethered, compliant-legged hexapod robot. RHex has only six actuators—one motor located at each hip— achieving mechanical simplicity that promotes reliable and robust operation in real-world tasks. Empirically stable and highly maneuverable locomotion arises from a very simple clock-driven, open-loop tripod gait. The legs rotate full circle, thereby preventing the common problem of toe stubbing in the protraction (swing) phase. An extensive suite of experimental results documents the robot’s significant “intrinsic mobility”—the traversal of rugged, broken, and obstacle-ridden ground without any terrain sensing or actively controlled adaptation. RHex achieves fast and robust forward locomotion traveling at speeds up to one body length per second and traversing height variations well exceeding its body clearance.
MSRox is a wheeled mobile robot with two actuated degrees of freedom which enables it to have smooth motion on flat surfaces.
It has the capability of climbing stairs and traversing obstacles, and adaptability toward uphill, downhill and slope surfaces.
MSRox with 82 cm in length, 54 cm in width and 29 cm in height has been designed to climb stairs of 10 cm in height and 15 cm
in width; nevertheless, it has the capability of climbing stairs up to about 17 cm in height and unlimited widt.
In this paper, the motion systems and the capabilities of MSRox are described. Furthermore, experimental results of stair
climbing and a comparison of the results with others are presented.
Small, tracked mobile robots designed for general urban mobility have been developed for the purpose of reconnaissance and/or search and rescue missions in buildings and cities. Autonomous stair climbing is a significant capability required for many of these missions. In this paper we present the design and implementation of a new set of estimation and control algorithms that increase the speed and effectiveness of stair climbing. We have developed: (1) a Kalman filter that fuses visual/laser data with inertial measurements and provides attitude estimates of improved accuracy at a high rate; and (2) a physics based controller that minimizes the heading error and maximizes the effective velocity of the vehicle during stair climbing. Experimental results using a tracked vehicle validate the improved performance of this control and estimation scheme over previous approaches.
This paper deals with the detection of the characteristics of
stairs, i.e. the number of steps, the step height and the step width for
online path planning of a bipedal robot. For the construction of a
multi-purpose, mobile platform for service robot applications with
special respect to the human environment, a biped is more advantageous
than a wheel based robot. In the framework of our studies, the bipedal
robot BARt-UH has been built and walking as well as the climbing of
stairs have been realized. The environment of the robot is assumed to be
structured, consisting of flat surfaces and stairs, but not known in
advance. Therefore, a state transition algorithm for intelligent path
planning of the robot is suggested. Further, a stereo vision module with
a line laser is considered, in order to detect the stair dimensions. The
necessary information is extracted from the projection of the line laser
onto the stairs. To achieve this, three algorithms were implemented and
a comparative study was carried out
In this paper, we present the mechanism, system configuration,
In this paper, we present the mechanism, system configuration,
basic control algorithm and integrated functions of the Honda humanoidbasic control algorithm and integrated functions of the Honda humanoid
robot. Like its human counterpart, this robot has the ability to moverobot. Like its human counterpart, this robot has the ability to move
forward and backward, sideways to the right or the left, as well asforward and backward, sideways to the right or the left, as well as
diagonally. In addition, the robot can turn in any direction, walk updiagonally. In addition, the robot can turn in any direction, walk up
and down stairs continuously. Furthermore, due to its unique postureand down stairs continuously. Furthermore, due to its unique posture
stability control, the robot is able to maintain its balance despitestability control, the robot is able to maintain its balance despite
unexpected complications such as uneven ground surfaces. As a part ofunexpected complications such as uneven ground surfaces. As a part of
its integrated functions, this robot is able to move on a planned pathits integrated functions, this robot is able to move on a planned path
autonomously and to perform simple operations via wireless teleoperationautonomously and to perform simple operations via wireless teleoperation
First Page of the Article
This paper describes the Player/Stage software tools applied to multi-robot, distributed-robot and sensor network systems. Player is a robot device server that provides network transparent robot control. Player seeks to constrain controller design as little as possible; it is device independent, non-locking and language- and style-neutral. Stage is a lightweight, highly congurable robot simulator that supports large populations. Player/Stage is a community Free Software project. Current usage of Player and Stage is reviewed, and some interesting research opportunities opened up by this infrastructure are identified.
Successful distributed sensing and control require data to flow effectively between sensors, processors and actuators on single robots, in groups and across the Internet. We propose a mechanism for achieving this ow which we have found to be powerful and easy to use; we call it Player. Player combines an efficient message protocol with a simple device model. It is implemented as a multi-threaded TCP socket server that provides transparent network access to a collection of sensors and actuators, often comprising a robot. The socket abstraction enables platform and language independent control of these devices, allowing the system designer to use the best tool for the task at hand. Player is freely available from http://robotics.usc.edu/player.
Climbing in the simple hexapod 'RHex'
- R D Quinn
- G M Nelson
- R J Bachmann
- D A Kingsley
- J Offi
- R E Ritzmann
Amphibious star-wheeled vehicle
- R W Forsyth
- J P Forsyth
Stair-climbing wheel chair
- R K Brown
Stair climbing vehicle
- J F Flory