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In this paper we present an algorithm, called the partitioned cubes gaiting (PCG) algorithm, for planning the foothold positions of spider-like robots in planar tunnels bounded by piecewise linear walls. The paper focuses on three-limb robots, but the algorithm generalizes to robots with a larger number of limbs. The input to the PCG algorithm is a...
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... foothold positions are represented as points in con- tact configuration space (c-space), which is defined as fol- lows. Let L be the total length of the tunnel walls, and let s i ∈ [0, L] be an arc-length parametrization of the position of the ith contact along the tunnel walls ( Figure 2). Then, for a k- limb mechanism contact c-space is the k-dimensional space (s 1 , . . . ...
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... L is total length of the tunnel walls and s i ∈ [0, L] is an arc-length parametrization of the ith contact (Figure 2). ...
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... I n be a partition of [0, L] into intervals that parametrize the individual walls by arc length. These intervals induce a partition of contact c-space into cubes (Figure 2). For instance, the cube I i ×I j ×I k parametrizes the three-limb pos- tures where limb 1 contacts the wall W i , limb 2 contacts the wall W j , and limb 3 contacts the wall W k . ...
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... section contains results of running the PCG algorithm on a simulated tunnel depicted in Figure 12. The tunnel consists of six walls whose lengths are marked in the figure. ...
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... walls are parametrized by path length in counterclock- wise order (Figure 12). Thus s = 0 and s = 270 correspond to the bottom and top of the tunnel's right side, while s = 270 and s = 540 correspond to the top and bottom of the tun- nel's left side. ...
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... segment in the figure is an edge of the sub- cube graph representing one limb lift-and-reposition step. Fig- ure 12 shows the same path in physical space, where each foothold is marked by its index in the sequence of steps taken by the robot. Let us denote the sequence of three-limb postures by (i 1 , i 2 , i 3 ), where i j is the foothold position of limb j at the ith stage. ...
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... too, that the short edge along the s 3 -axis in Figure 11 corresponds to the transition (7, 8, 6) → (7, 8, 9). This edge takes the robot around the corner between the walls W 5 and W 6 in Figure 12. The difficulty in accomplishing this maneuver can be appreciated by inspecting the narrow overlap between the planar cells I 5 × I 1 and I 6 × I 1 in Figure 7. ...
Citations
... As mentioned before, there are currently different robot applications, like a spidershaped robot developed to support robot points used to move in flat tunnels. Its design is based on three limbs articulated in a central body, which determines posture stability and moves by stepping two legs on the tunnel walls while one moves [9]. Spider robot with eight legs was developed to move on flat surfaces, on vertical and inverted walls. ...
... Three-limb spiderlike robot [9] Inspection of planar tunnel environments. ...
This paper presents a biomimetic prototype of a mobile robot that can be used to inspect the subdrainage conditions of pipelines located along different highways in Mexico. Computer-aided design tools have been used to size each of the prototype components as inspired by anatomical spider structure. Springs are integrated to generate proper contact pressure against the pipe walls. The robot locomotion system is implemented with adaptable behaviour for the irregularities of pipelines along its journey. The robot prototype is manufactured in 3D printing with the advantage of having its spare parts easily replaceable. Reported results show internal pipe status through a mini video camera on the top of the robot.
... Much work exists on spider robot with most them focusing on motion planning and some form of leg control algorithm - [28][29][30][31]. This current work is rather an attempt at gaining insight into the intelligence behind the salticidae family of spiders when interacting with their environment. ...
Aims: The main objective of this work is to develop a simple robot that can imitate the jumping spider (Salticidae) in its motion, as a first stage to building a complete robot that mimics them in many ways. Methodology: Biological systems are really complex in their complete make up; therefore the biomimicry employed here is to imitate scan-pause-scan motion employed by the spider. Their anterior media eye (the big eye) is imitated using a sonar sensor. The pausing period allows the robot to analyse the environment using low cost/ low power microcontroller. The system was then tested with different object at its front in other to investigate the robot one direction performance. Results: Most object were detected except when the object was 2 mm 2 size wire gauze. In its case the robot did not slowdown as it approaches it. For all other objects, the robot slowed down before reaching them-although it did not apply enough braking force before it reach some of those obstacle. It was also found out that the robot performed up to 45 scans within the period it was moving towards the objects placed at 1 m ahead. Conclusion: This work is a preliminary work on the robot as first step in imitating the spider. The robot was able to imitate the biological model, jumping spiders (Salticidae) successfully in its pause-scan and move motion only – with the robot speeding whenever no obstacle was detected.
... In addition, the stride phase is defined as the period when attachment or detachment of one of the grasping mechanism occurs in order to conduct a step. Similar to other spider like robots [25][26][27] SpiderBot assumes movement in a quasi-static manner. In quasi-static motion, the inertial forces are kept small with respect to the external forces. ...
... The Alicia 3 robot climbs walls by using pneumatic adhesion at one or more of three "cups" connected by two links [22]. The climbing robots in [23], [24] climb by kinematic or quasistatic bracing between opposing walls. The four-limbed free-climbing LEMUR robot goes up climbing walls by choosing a sequence of footholds and motions that keep the robot in static equilibrium at all times [25]. ...
The ParkourBot climbs in a planar reduced-gravity vertical chute by leaping back and forth between the chute’s two parallel walls. The ParkourBot is comprised of a body with two springy legs and its controls consist of leg angles at touchdown and the energy stored in them. During flight, the robot stores elastic potential energy in its springy legs and then converts this potential energy in to kinetic energy at touchdown, when it “kicks off” a wall. This paper describes the ParkourBot’s mechanical design, modeling, and open-loop climbing experiments. The mechanical design makes use of the BowLeg, previously used for hopping on a flat ground. We introduce two models of the BowLeg ParkourBot: one is based on a nonzero stance duration using the spring-loaded inverted pendulum model, and the other is a simplified model (the simplest parkour model, or SPM) obtained as the leg stiffness approaches infinity and the stance time approaches zero. The SPM approximation provides the advantage of closed-form calculations. Finally, predictions of the models are validated by experiments in open-loop climbing in a reduced-gravity planar environment provided by an air table.
... The applications include surveillance, transportation, health care, reconnaissance, save and rescue, pursuit-evasion, and explorations in either fully known or partially known environments that may be very harsh, hazardous, dull or dirty, or even inaccessible to humans [6]. Researchers from various disciplines have considered collision-free trajectories of agents in environments that include tunnels [7][8][9][10][11][12][13]. In particular, we refer to the work carried out by Belta and Kumar in [7] who considered tunnel passing maneuver of a team of robots gathered inside a specific shape such as an ellipse or a rectangle. ...
Tunnel passing is a pattern formation of multiple robots, an outcome of formation control which is the general problem of controlling a large number of robots required to move as a group. Tunnel passing deals with the task of driving a team of robots from arbitrary initial positions through a tunnel of given geometry. This paper proposes a decentralized planner that guarantees collision‐free tunnel passing maneuvers of a team of nonholonomic car‐like robots fixed in a prescribed formation, while considering all the practical limitations and constraints due to nonholonomy, tunnel geometry, and the formation specifications. Although solutions in literature are restricted to tunnels with linear segments, this paper introduces piecewise tunnel walls with straight and curved segments. The motion planner, derived from the Lyapunov‐based control scheme works within an overarching leader‐follower framework to generate either split/rejoin or expansion/contraction of the formation, as feasible solutions. Results from simulating virtual scenarios demonstrated the effectiveness of the proposed nonlinear controllers. Copyright © 2012 John Wiley & Sons, Ltd.
... Since then, and following the advance of control technique technologies, computing resources and motion actuators, many different robots with varied abilities have been built. Examples of these abilities include running [3], walking over rough terrain, jumping over obstacles [4], climbing [5,6] and more. ...
This paper presents the design of a novel quadruped robot. The proposed design is characterized by a simple, modular design, and easy interfacing capabilities. The robot is built mostly from off-the-shelf components. The design includes four 3-DOF legs, the robot body and its electronics. The proposed robot is able to traverse rough terrain while carrying additional payloads. Such payloads can include both sensors and computational hardware. We present the robot design, the control system, and the forward and inverse kinematics of the robot, as well as experiments that are compared with simulation results.
... Control methods associated with the traditional robotics "sense-think-act" paradigm often presume the availability of local world models amenable to planned paths that, when executed, produce successful locomotion. Often applied to footfall planning (Wettergreen et al., 1990;Chestnutt et al., 2005;Shapiro et al., 2005;Bretl, 2006;Hodoshima et al., 2004), these methods require accurate sensor information as well as detailed environmental representations. Notwithstanding their rational design appeal, these methods are difficult to implement on small, fast, and possibly dynamic legged machines. ...
We develop robust methods that allow the specification, control, and transition of a multi-legged robot’s stepping pattern, its ‘gait’, during active locomotion over natural terrain. Resulting gaits emerge through the introduction of controllers that impose appropriately placed repellors within the space of gaits, the torus of relative leg phases, thereby mitigating against dangerous patterns of leg timing. Moreover, these repellors are organized with respect to a natural cellular decomposition of gait space and result in limit cycles with associated basins that are well characterized by these cells, thus conferring a symbolic character upon the overall behavioral repertoire. These ideas are particularly applicable to four- and six-legged robots, for which a large variety of interesting and useful (and, in many cases, familiar) gaits exist, and whose tradeoffs between speed and reliability motivate the desire for transitioning between them during active locomotion. We provide an empirical instance of this gait regulation scheme by application to a climbing hexapod, whose ‘physical layer’ sensor-feedback control requires adequate grasp of a climbing surface but whose closed-loop control perturbs the robot from its desired gait. We document how the regulation scheme secures the desired gait and permits operator selection of different gaits as required during active climbing on challenging surfaces.
... In the searchbased method, a different series of possible robot motions is generated and a search for a valid motion or motion This sequences is applied. The most significant drawbacks of the search method is the high computations requirements for searching a very large number of possible motion series, especially when searching for the optimal path [17] and the need of a prior knowledge about the terrain characteristics. However, we believe that the computers technology for high complexity calculations and terrain data gathering sensors has come to an adequate level for the use of a search-based method and the use of such technologies can significantly improve results for gait generation over rough terrains. ...
This paper presents an algorithm for planning the foothold positions of quadruped robots on irregular terrain. The input to the algorithm is the robot kinematics, the terrain geometry, a required motion path, as well as initial posture. Our goal is to develop general algorithm that navigate quadruped robots quasi-statically over rough terrain, using an APF (Artificial Potential Field) and graph searching. The algorithm is planning a sequence set of footholds that navigates the robot along the required path with controllable motion characteristics. Simulations results demonstrate the algorithm in a planner environment.
... The Alicia3 robot climbs walls by using pneumatic adhesion at one or more of three "cups" connected by two links [16]. The climbing robots in [17], [18] climb by kinematic or quasistatic bracing between opposing walls. The four-limbed free-climbing LEMUR robot goes up climbing walls by choosing a sequence of footholds and motions that keep the robot in static equilibrium at all times [19]. ...
The ParkourBot is an efficient and dynamic climb- ing robot. The robot comprises two springy legs connected to a body. Leg angle and spring tension are independently controlled. The robot climbs between two parallel walls by leaping from one wall to the other. During flight, the robot stores elastic energy in its springy legs and automatically releases the energy to "kick off" the wall during touch down. This paper elaborates on the mechanical design of the ParkourBot. We use a simple SLIP model to simulate the ParkourBot motion and stability. Finally, we detail experimental results, from open-loop climbing motions to closed-loop stabilization of climbing height in a planar, reduced gravity environment.
... The Alicia3 robot climbs walls by using pneumatic adhesion at one or more of three "cups" connected by two links (Longo and Muscato, 2006). The climbing robots of Shapiro et al. (2005) and Greenfield et al. (2005) climb by kinematic or quasistatic bracing between opposing walls. Bretl (2006) and Bevly et al. (2000) both use foothold based climbing strategies. ...
Dynamics in locomotion is highly useful, as can be seen in animals. Although dynamic maneuvers are beneficial, only a few engineered systems use them as the design and control are often extremely complicated. This thesis explores a family of dynamic climbing robots which extend robotic dynamic legged locomotion from horizontal motions such as walking and running, to vertical motions such as leaping. Motion of these dynamic robots resembles the motion of an athlete jumping and climbing inside a chute. The mechanisms described achieve dynamic, vertical motions while retaining simplicity in design and control. The first mechanism called DSAC, for Dynamic Single Actuated Climber, comprises only two links connected by a single oscillating actuator. This simple, open-loop oscillation, propels the robot stably between two vertical walls. By rotating the axis of revolution of the single actuator by 90 degrees, we also developed a simpler robot that can be easily miniaturized and can be used to climb inside tubes. The DTAR, for Dynamic Tube Ascending Robot, uses a single continuously rotating motor, unlike the oscillating DSAC motor. This continuous rotation even further simplifies and enables the miniaturization. The last mechanism explored is the ParkourBot which sacrifices some simplicity shown in the first two mechanism in favor of efficiency and more versatile climbing. This mechanism comprises two efficient springy legs connected to a body. We use this family of dynamic climbers to explore a minimalist approach to locomotion. We first analyze open-loop stability characteristics. We show an open-loop, sensorless control, such as fixed oscillation of the DSAC's leg can converge to a stable orbit. We show change in the mechanism's parameters not only changes the stability, but also changes the climbing pattern from a symmetric climb to a limping, non-symmetric climb. We show open-loop behavior can be used to traverse more complex terrains by incrementally adding feedback.
