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Sensing principle of the soft robot arm motion by wire encoders: (a) Configuration of the sensing system. (b) Sensing principle for the bending motion. (c) Sensing principle for the torsional motion.
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An octopus arm with a flexible structure and no rigid skeleton shows a high degree of freedom and flexibility. These excellent features are suitable for working in an environment having fragile and unknown-shaped objects. Therefore, a soft robot arm resembling an octopus arm can be useful as a harvesting machine without damaging crops in the agricu...
Citations
... Over the last two decades, octopuses have been the source of inspiration for robotics. For instance, research on octopus motor control (see previous section) significantly contributed to the design and control of an octopus-like robotic arm (Laschi et al., 2009(Laschi et al., , 2012Guglielmino et al., 2012;Cianchetti et al., 2015;Furukawa et al., 2019). In fact, soft robotics largely benefit from a conceptual design of an octopus-inspired robot. ...
This chapter describes past and present publication trends in octopus research following a systematic mapping approach. Publication rates in popular research topics such as life history and ecology are decreasing, while others are increasing and taking the spotlight. Interest in behaviour has seen a considerable uptick in recent years. Also, rapid advances, emerging tools, and widespread access to DNA sequence information have stimulated an increased focus on topics relating to genomics & evolution. Research related to diversity & bBiogeo-graphy is also increasing, especially in the context of the concurrent biodiversity and climate crises. Although global change represents the least studied topic to date, interest has increased tremendously over the past 5 years, with more than double the publication rate observed for behaviour (the topic with the second largest publication rate). Our analysis also provides a geographical perspective; the food and argriculture organization region with the most octopus-related studies is the Mediterranean, followed by the Northeast and Western-Central Atlantic Ocean. Regarding species of interest, Octopus vulgaris stands out as the overwhelming front-runner Octopus Biology and Ecology. https://doi. 421 representing more than half of all records and over five times more than the second most studied species, Octopus maya. We also provide a discussion on future directions for key subjects, including behaviour and cognition, iEcology and citizen science, bio-robotics, deep-sea research, climate change, and culture and welfare, among others, with the hope of providing an agenda for future research.
... Research related to bio-inspired SPA design, such as octopus (Furukawa et al. 2019) and fish fins (Razif et al. 2014), has been done before. However, the fabrication carried out does not use FDM technology. ...
Strain sensors and soft pneumatic actuators are required to make sensorized soft pneumatic actuators. Conventionally, the strain sensors and soft pneumatic actuators are fabricated separately and then embedded afterward. The process was time- and resource-consuming. Fabricating a Sensorized Soft Pneumatic Actuator efficiently, cheaply, and relatively quickly becomes a desirable theme. The fabrication process can overcome these desires by developing Fused Deposition Modeling (FDM) technology. Many studies have been conducted, but the FDM process of fabricating sensorized soft pneumatic actuators is rarely discussed. Many literature reviews on strain sensors and soft pneumatic actuators are available, yet they are in separate resources. Meanwhile, the process of making a sensorized soft pneumatic actuator requires both. A literature review of the application of FDM to both strain sensors and soft pneumatic actuators has never been carried out. Yet, it is necessary to investigate the research gaps and opportunities for further development. This way, the downstream process of the sensorized soft pneumatic actuator-based products can be immediately developed and utilized by relevant parties. Using the systematical literature review, 53 studies were investigated regarding material, shape, characteristics, and applications. The investigation indicates that the topic leaves opportunities for further development, such as for commercial purposes. It is also possible to explore the parameters and the product’s characteristics.
... 21 With regard to muscular hydrostats inspired by octopodes' arms, researchers have employed artificial muscles such as shape-memory alloys (SMAs), 22-25 dielectric elastomers (DEs), [26][27][28] and McKibben actuators for driving soft robotic manipulators. [29][30][31][32] However, these artificial muscles present significant limitations: McKibben actuators show high-power density, speed, and high strain values but need heavy and noisy air compressors for actuation; 33 SMAs can generate high stress values but they are expensive, difficult to control, and exhibit significant hysteresis during contraction; 34 DEs exhibit high strain values but they require high voltages (kilo-megavolt range) and prestraining for their operation. 35 FIG. 1. Bioinspiration and TCAM arrangement for the proposed hydrostats. ...
Traditional robots are characterized by rigid structures, which restrict their range of motion and their application in environments where complex movements and safe human-robot interactions are required. Soft robots inspired by nature and characterized by soft compliant materials have emerged as an exciting alternative in unstructured environments. However, the use of multicomponent actuators with low power/weight ratios has prevented the development of truly bioinspired soft robots. Octopodes' limbs contain layers of muscular hydrostats, which provide them with a nearly limitless range of motions. In this work, we propose octopus-inspired muscular hydrostats powered by an emerging class of artificial muscles called twisted and coiled artificial muscles (TCAMs). TCAMs are fabricated by twisting and coiling inexpensive fibers, can sustain stresses up to 60 MPa, and provide tensile strokes of nearly 50% with <0.2 V/cm of input voltage. These artificial muscles overcome the limitations of other actuators in terms of cost, power, and portability. We developed four different configurations of muscular hydrostats with TCAMs arranged in different orientations to reproduce the main motions of octopodes' arms: shortening, torsion, bending, and extension. We also assembled an untethered waterproof device with on-board control, sensing, actuation, and a power source for driving our hydrostats underwater. The proposed TCAM-powered muscular hydrostats will pave the way for the development of compliant bioinspired robots that can be used to explore the underwater world and perform complex tasks in harsh and dangerous environments.
... Al-Ibadi et al. [89] presented a mathematical model that relates muscle elongation to applied pressure, considering weight variations and muscle orientation. Furukawa et al. [90] described a soft robot arm mimicking an octopus arm, implementing feedback control in a master-slave system. Furthermore, Azizkhani et al. [91] investigated control approaches for a one-segment soft robotic arm actuated pneumatically, addressing practical issues such as sensor noise and hysteresis. ...
In this research paper, we present a comprehensive analysis of the current state of soft robots actuated with pneumatic artificial muscles and emphasise their distinct advantages over rigid robots, including exceptional flexibility, adaptability, and safety. Our study explores the design principles of soft robots, drawing inspiration from biological systems and human hands, and identifies promising avenues for further development. The emergence of hybrid robots is also recognised as a significant advancement, particularly in scenarios requiring high precision. The article explores mathematical models encompassing kinematics, dynamics, and statics, as well as alternative model-free approaches. These theoretical frameworks are instrumental in understanding and manipulating the behaviour of soft robots. However, despite substantial progress, soft robots’ practical application and simulation face limitations, primarily due to the demanding requirements and implementation challenges associated with their deployment. Consequently, this paper highlights the need for continued research and advancements to bridge the gap between the theoretical potential and practical utilisation of soft robots.
... The bio-simulating actuator based on soft materials can offer a wide variety of possible applications, including those requiring adaptability. Accordingly, studies on soft actuators imitating animals are actively being conducted to attain their own aim [1][2][3]. These soft actuators are usually inspired by the muscles of an organism [4,5]. ...
Soft actuators that execute diverse motions have recently been proposed to improve the usability of soft robots. Nature-inspired actuators, in particular, are emerging as a means of accomplishing efficient motions based on the flexibility of natural creatures. In this research, we present an actuator capable of executing multi-degree-of-freedom motions that mimics the movement of an elephant’s trunk. Shape memory alloys (SMAs) that actively react to external stimuli were integrated into actuators constructed of soft polymers to imitate the flexible body and muscles of an elephant’s trunk. The amount of electrical current provided to each SMA was adjusted for each channel to achieve the curving motion of the elephant’s trunk, and the deformation characteristics were observed by varying the quantity of current supplied to each SMA. It was feasible to stably lift and lower a cup filled with water by using the operation of wrapping and lifting objects, as well as effectively performing the lifting task of surrounding household items of varying weights and forms. The designed actuator is a soft gripper that incorporates a flexible polymer and an SMA to imitate the flexible and efficient gripping action of an elephant trunk, and its fundamental technology is expected to be used as a safety-enhancing gripper that requires environmental adaptation.
... With the use of specialized sensors, including machine vision, laser-based devices, and inertial devices, actuators (hydraulic cylinders, linear and rotary motors, etc.) play an essential role in enabling the agricultural robots to execute different tasks via the help of electronic devices (embedded computers, industrial computers, and programmable logic controller) [28][29][30]. An agricultural robot end-effector's most important function is the flexibility to handle the work object, comparably to human arms and fingers [31,32]. At present, a wide variety of end devices have been developed, with fingers, attractors, needles, spray nozzles, scissors, and robotic arms, to grip, cut, attach, or press into crops to effectively perform all biological production processes, which include picking, harvesting, The drive system, as the main component of the robot, can be classified into electric, hydraulic, and pneumatic types, based on the different applications of agricultural robots [27]. ...
... With the use of specialized sensors, including machine vision, laser-based devices, and inertial devices, actuators (hydraulic cylinders, linear and rotary motors, etc.) play an essential role in enabling the agricultural robots to execute different tasks via the help of electronic devices (embedded computers, industrial computers, and programmable logic controller) [28][29][30]. An agricultural robot end-effector's most important function is the flexibility to handle the work object, comparably to human arms and fingers [31,32]. At present, a wide variety of end devices have been developed, with fingers, attractors, needles, spray nozzles, scissors, and robotic arms, to grip, cut, attach, or press into crops to effectively perform all biological production processes, which include picking, harvesting, spraying, sowing, transplanting, shaping, primary processing, shearing, and milking [33][34][35]. ...
In recent years, with the rapid development of science and technology, agricultural robots have gradually begun to replace humans, to complete various agricultural operations, changing traditional agricultural production methods. Not only is the labor input reduced, but also the production efficiency can be improved, which invariably contributes to the development of smart agriculture. This paper reviews the core technologies used for agricultural robots in non-structural environments. In addition, we review the technological progress of drive systems, control strategies, end-effectors, robotic arms, environmental perception, and other related systems. This research shows that in a non-structured agricultural environment, using cameras and light detection and ranging (LiDAR), as well as ultrasonic and satellite navigation equipment, and by integrating sensing, transmission, control, and operation, different types of actuators can be innovatively designed and developed to drive the advance of agricultural robots, to meet the delicate and complex requirements of agricultural products as operational objects, such that better productivity and standardization of agriculture can be achieved. In summary, agricultural production is developing toward a data-driven, standardized, and unmanned approach, with smart agriculture supported by actuator-driven-based agricultural robots. This paper concludes with a summary of the main existing technologies and challenges in the development of actuators for applications in agricultural robots, and the outlook regarding the primary development directions of agricultural robots in the near future.
... In addition, Liu et al. developed a sheath-core electrothermal fiber actuator, in which the core is the elastomer and the sheath is the carbon nanotubes; this fiber could be twisted under electric heat and the capacitance of the fiber was almost linearly related to the strain (Liu et al., 2015). Other examples such as heating resistor and strain sensor in an origami robot , thread sensors in the PAMs (Furukawa et al., 2019), resistance strain sensor in fiber/yarn actuators (Foroughi et al., 2016;Kanik et al., 2019) all demonstrate the great potential of textile-based sensors in human-robot interaction. ...
Soft robotics have substantial benefits of safety, adaptability, and cost efficiency compared to conventional rigid robotics. Textiles have applications in soft robotics either as an auxiliary material to reinforce the conventional soft material or as an active soft material. Textiles of various types and configurations have been fabricated into key components of soft robotics in adaptable formats. Despite significant advancements, the efficiency and characteristics of textile actuators in practical applications remain unsatisfactory. To address these issues, novel structural and material designs as well as new textile technologies have been introduced. Herein, we aim at giving an insight into the current state of the art in textile technology for soft robotic manufacturing. We firstly discuss the fundamental actuation mechanisms for soft robotics. We then provide a critical review on the recently developed functional textiles as reinforcements, sensors, and actuators in soft robotics. Finally, the future trends and current strategies that can be employed in textile-based actuator manufacturing process have been explored to address the critical challenges in soft robotics.
... In these fields, unlike for general industrial robot arms, where predetermined motions are repeated at high speed based on high-precision positioning control, the operator's intention needs to be reflected flexibly in the motions of the robot arm, depending on the situation and task. For intentional operation, research has been conducted on master-slave control using a manipulation interface that is similar to that of the robot arm, and on remote control using human motions through wearable devices [9][10][11][12]. In this study, we have developed an arm-mounted wearable interface with thin flexible strain sensors attached to a highly elastic arm cover. ...
... The interface detects the flexion of the operator's wrist and the twist of the operator's forearm, and these are used as inputs for the bending and twisting motions of the soft robotic arm, respectively. This enables intuitive operation of the soft robot arm [10]. In order to reflect the operator's intention more efficiently in the motion of the soft robotic arm, it is effective to introduce feedback control to the master-slave operation. ...
... Eng. Proc. 2021, 10, 34 2 of 7 operation of the soft robot arm [10]. In order to reflect the operator's intention more efficiently in the motion of the soft robotic arm, it is effective to introduce feedback control to the master-slave operation. ...
In our study, a soft robot arm consisting of McKibben artificial muscles and a silicone rubber structure was developed. This robot arm can perform bending and twisting motions by ap-plying pneumatic pressure to the artificial muscles. The robot arm is made of flexible materials only, and therefore it has high flexibility and shape adaptability. In this report on the fundamental investigation of the master–slave feedback control of the soft robot arm for intentional operation, we focus on the bending motion of the soft robot arm. Three flexible strain sensors were placed on the soft robot arm for measuring the bending motion. By establishing a master–slave feedback system using the sensors, the bending motion of the soft robot arm followed the operator’s wrist motion detected via the wearable interface device.
... Currently, many types of pneumatic soft actuators have been researched and developed [3][4][5][6]. They have also been applied to robot arms and hands as a safe driving source [7][8][9][10][11]. ...
The bellows pneumatic actuator, which is made by folding a non-stretch film, has been proposed for various applications because it is easy to fabricate and is extremely thin and light. However, it has subpar durability performance, especially in the folded part of the film. In this study, we propose an actuator with a pod structure that possesses high design flexibility and is free from folding. A method of molding a pod structure on a polyimide film was established and a pneumatic actuator was successfully fabricated by using PI films. Two types of PI film pneumatic actuators with the same curvature, bellows type, and pod type were fabricated. Both were confirmed to have equivalent output characteristics. The bending angle and generated torque of the pod-structure actuator were 34° and 3.3 mNm, respectively. In addition, the pod structure has approximately twice the durability of the bellows structure. By using the fabrication method proposed in this paper, it is possible to realize an air chamber (i.e., an actuator) that has both high durability and bending motion.
... In the field of soft actuators, a fiber-reinforced elastomeric enclosure (FREE) developed by McKibben et al. [1][2][3][4][5][6] has attracted attention because of its simple structure, high forceto-weight ratio, and high pressure. These unique capabilities enable a variety of potential medical device applications [7,8]. ...
Unlike rigid actuators, soft actuators can easily adapt to complex environments. Understanding the relationship between the deformation of soft actuators and external factors such as pressure would enable rapid designs based on specific requirements, such as flexible, compliant endoscopes. An effective model is demonstrated that predicts the deformation of a soft actuator based on the virtual work principle and the geometrically exact Cosserat rod theory. The deformation process is analyzed for extension, bending, and twisting modules. A new manufacturing method is then introduced. Through any combination of modules, the soft actuator can have a greater workspace and more dexterity. The proposed model was verified for various fiber-reinforced elastomeric enclosures. There is good agreement between the model analysis and the experimental data, which indicates the effectiveness of the model.
