Special Issue "Bio-Inspired Robotics"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (15 November 2017).

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A printed edition of this Special Issue is available here.

Special Issue Editors

Prof. Dr. Toshio Fukuda
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Guest Editor
1. Institute for Advanced Research, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
2. Department of Mechatronics Engineering, Meijo University, Nagoya, Aichi Prefecture 468-0073, Japan
3. School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, 100081, China
Interests: intelligent robotic and mechatronic system; cellular robotic system; micro- and nano-robotic system
Special Issues and Collections in MDPI journals
Dr. Fei Chen
E-Mail Website
Guest Editor
Department of Advanced Robotics, Italian Institute of Technology. Via Morego 30, 16163 Genova, Italy
Interests: mobile and dexterous manipulation; collaborative robotics; robot learning
Special Issues and Collections in MDPI journals
Assoc. Prof. Qing Shi
E-Mail Website
Guest Editor
Intelligent Robotics Institute, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing, 100081, China
Interests: biomimetic robots; cognitive robots; robotic vision
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Modern robotic technologies have enabled robots to operate in a variety of unstructured and dynamically-changing environments, in addition to traditional structured environments. Robots have, thus, become an important element in our everyday lives. One key approach to develop such intelligent and autonomous robots is to draw inspiration from biological systems. Biological structure, mechanisms, and underlying principles have the potential to feed new ideas to support the improvement of conventional robotic designs and control. Such biological principles usually originate from animal or even plant models for robots, which can sense, think, walk, swim, crawl, or fly. Thus, it is believed that these bio-inspired methods are becoming increasingly important in the face of complex applications. Bio-inspired robotics is leading to the study of innovative structures and computing with sensory-motor coordination and learning to achieve intelligence, flexibility, stability, and adaptation for emergent robotic applications, such as manipulation, learning, and control.

This Special Issue invites original papers of innovative ideas and concepts, new discoveries and improvements, and novel applications and business models relevant to the selected topics of "Bio-Inspired Robotics".

Professor Toshio Fukuda
Dr. Fei Chen
Dr. Qing Shi
Guest Editors

Manuscript Submission Information

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Keywords

  • Bio-inspired manipulation

  • Bio-inspired learning and control

  • Bio-inspired sensory-motor coordination

  • Bio-inspired robot design and application

  • Bio-inspired computation for robots

  • Biomimetic robots

  • Bio-inspired robotic locomotion

  • Cyber-physical bio-system

Published Papers (31 papers)

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Editorial

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Editorial
Special Feature on Bio-Inspired Robotics
Appl. Sci. 2018, 8(5), 817; https://doi.org/10.3390/app8050817 - 18 May 2018
Cited by 1 | Viewed by 1404
(This article belongs to the Special Issue Bio-Inspired Robotics)

Research

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Article
Characterization of Control-Dependent Variable Stiffness Behavior in Discrete Muscle-Like Actuators
Appl. Sci. 2018, 8(3), 346; https://doi.org/10.3390/app8030346 - 28 Feb 2018
Cited by 3 | Viewed by 2316
Abstract
This paper presents the modeling, characterization and validation for a discrete muscle-like actuator system composed of individual on–off motor units with complex dynamics inherent to the architecture. The dynamics include innate hardening behavior in the actuator with increased length. A series elastic actuator [...] Read more.
This paper presents the modeling, characterization and validation for a discrete muscle-like actuator system composed of individual on–off motor units with complex dynamics inherent to the architecture. The dynamics include innate hardening behavior in the actuator with increased length. A series elastic actuator model is used as the plant model for an observer used in feedback control of the actuator. Simulations are performed showing the nonlinear nature of the changing stiffness as well as how this affects the dynamics, clearly observed in the phase portrait. Variable-stiffness hardening behavior is evaluated in experiment and shows good agreement with the model. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Bio-Inspired Optimal Control Framework to Generate Walking Motions for the Humanoid Robot iCub Using Whole Body Models
Appl. Sci. 2018, 8(2), 278; https://doi.org/10.3390/app8020278 - 12 Feb 2018
Cited by 9 | Viewed by 2527
Abstract
Bipedal locomotion remains one of the major open challenges of humanoid robotics. The common approaches are based on simple reduced model dynamics to generate walking trajectories, often neglecting the whole-body dynamics of the robots. As motions in nature are often considered as optimal [...] Read more.
Bipedal locomotion remains one of the major open challenges of humanoid robotics. The common approaches are based on simple reduced model dynamics to generate walking trajectories, often neglecting the whole-body dynamics of the robots. As motions in nature are often considered as optimal with respect to certain criteria, in this work, we present an optimal control-based approach that allows us to generate optimized walking motions using a precise whole-body dynamic model of the robot, in contrast with the common approaches. The optimal control problem is formulated to minimize a set of desired objective functions with respect to physical constraints of the robot and contact constraints of the walking phases; the problem is then solved with a direct multiple shooting method. We apply the formulation with combinations of different objective criteria to the model of a reduced version of the iCub humanoid robot of 15 internal DOF. The obtained trajectories are executed on the real robot, and we carry out a discussion on the differences between the outcomes of this approach with the classic approaches. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Effective Biopotential Signal Acquisition: Comparison of Different Shielded Drive Technologies
Appl. Sci. 2018, 8(2), 276; https://doi.org/10.3390/app8020276 - 12 Feb 2018
Cited by 18 | Viewed by 2768
Abstract
Biopotential signals are mainly characterized by low amplitude and thus often distorted by extraneous interferences, such as power line interference in the recording environment and movement artifacts during the acquisition process. With the presence of such large-amplitude interferences, subsequent processing and analysis of [...] Read more.
Biopotential signals are mainly characterized by low amplitude and thus often distorted by extraneous interferences, such as power line interference in the recording environment and movement artifacts during the acquisition process. With the presence of such large-amplitude interferences, subsequent processing and analysis of the acquired signals becomes quite a challenging task that has been reported by many previous studies. A number of software-based filtering techniques have been proposed, with most of them being able to minimize the interferences but at the expense of distorting the useful components of the target signal. Therefore, this study proposes a hardware-based method that utilizes a shielded drive circuit to eliminate extraneous interferences on biopotential signal recordings, while also preserving all useful components of the target signal. The performance of the proposed method was evaluated by comparing the results with conventional hardware and software filtering methods in three different biopotential signal recording experiments (electrocardiogram (ECG), electro-oculogram (EOG), and electromyography (EMG)) on an ADS1299EEG-FE platform. The results showed that the proposed method could effectively suppress power line interference as well as its harmonic components, and it could also significantly eliminate the influence of unwanted electrode lead jitter interference. Findings from this study suggest that the proposed method may provide potential insight into high quality acquisition of different biopotential signals to greatly ease subsequent processing in various biomedical applications. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Trajectory Tracking of an Omni-Directional Wheeled Mobile Robot Using a Model Predictive Control Strategy
Appl. Sci. 2018, 8(2), 231; https://doi.org/10.3390/app8020231 - 02 Feb 2018
Cited by 51 | Viewed by 4516
Abstract
This paper addresses trajectory tracking of an omni-directional mobile robot (OMR) with three mecanum wheels and a fully symmetrical configuration. The omni-directional wheeled robot outperforms the non-holonomic wheeled robot due to its ability to rotate and translate independently and simultaneously. A kinematics model [...] Read more.
This paper addresses trajectory tracking of an omni-directional mobile robot (OMR) with three mecanum wheels and a fully symmetrical configuration. The omni-directional wheeled robot outperforms the non-holonomic wheeled robot due to its ability to rotate and translate independently and simultaneously. A kinematics model of the OMR is established and a model predictive control (MPC) algorithm with control and system constraints is designed to achieve point stabilization and trajectory tracking. Simulation results validate the accuracy of the established kinematics model and the effectiveness of the proposed MPC controller. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Three-Dimensional Modeling of a Robotic Fish Based on Real Carp Locomotion
Appl. Sci. 2018, 8(2), 180; https://doi.org/10.3390/app8020180 - 26 Jan 2018
Cited by 18 | Viewed by 2744
Abstract
This work focuses on developing a complete non-linear dynamic model comprising entirely kinematic and hydrodynamic effects of Carangiform locomotion based on the Lagrange approach by adapting the parameters and behaviors of a real carp. In order to imitate biological features, swimming patterns of [...] Read more.
This work focuses on developing a complete non-linear dynamic model comprising entirely kinematic and hydrodynamic effects of Carangiform locomotion based on the Lagrange approach by adapting the parameters and behaviors of a real carp. In order to imitate biological features, swimming patterns of a real carp for forward, turning and up-down motions are analyzed by using the Kineova 8.20 software. The proportional optimum link lengths according to actual size, swimming speed, flapping frequency, proportional physical parameters and different swimming motions of the real carp are investigated with the designed robotic fish model. Three-dimensional (3D) locomotion is evaluated by tracking two trajectories in a MATLAB environment. A Reaching Law Control (RLC) approach for inner loop (Euler angles-speed control) and a guidance system for the outer loop (orientation control) are proposed to provide an effective closed-loop control performance. In order to illustrate the 3D performance of the proposed closed loop control system in a virtual reality platform, the designed robotic fish model is also implemented using the Virtual Reality Modeling Language (VRML). Simulation and experimental analysis show that the proposed model gives us significant key solutions to design a fish-like robotic prototype. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Hybrid Locomotion Evaluation for a Novel Amphibious Spherical Robot
Appl. Sci. 2018, 8(2), 156; https://doi.org/10.3390/app8020156 - 24 Jan 2018
Cited by 40 | Viewed by 2763
Abstract
We describe the novel, multiply gaited, vectored water-jet, hybrid locomotion-capable, amphibious spherical robot III (termed ASR-III) featuring a wheel-legged, water-jet composite driving system incorporating a lifting and supporting wheel mechanism (LSWM) and mechanical legs with a water-jet thruster. The LSWM allows the ASR-III [...] Read more.
We describe the novel, multiply gaited, vectored water-jet, hybrid locomotion-capable, amphibious spherical robot III (termed ASR-III) featuring a wheel-legged, water-jet composite driving system incorporating a lifting and supporting wheel mechanism (LSWM) and mechanical legs with a water-jet thruster. The LSWM allows the ASR-III to support the body and slide flexibly on smooth (flat) terrain. The composite driving system facilitates two on-land locomotion modes (sliding and walking) and underwater locomotion mode with vectored thrusters, improving adaptability to the amphibious environment. Sliding locomotion improves the stability and maneuverability of ASR-III on smooth flat terrain, whereas walking locomotion allows ASR-III to conquer rough terrain. We used both forward and reverse kinematic models to evaluate the walking and sliding gait efficiency. The robot can also realize underwater locomotion with four vectored water-jet thrusters, and is capable of forward motion, heading angle control and depth control. We evaluated LSWM efficiency and the sliding velocities associated with varying extensions of the LSWM. To explore gait stability and mobility, we performed on-land experiments on smooth flat terrain to define the optimal stride length and frequency. We also evaluated the efficacy of waypoint tracking when the sliding gait was employed, using a closed-loop proportional-integral-derivative (PID) control mechanism. Moreover, experiments of forward locomotion, heading angle control and depth control were conducted to verify the underwater performance of ASR-III. Comparison of the previous robot and ASR-III demonstrated the ASR-III had better amphibious motion performance. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Motion Planning for Bipedal Robot to Perform Jump Maneuver
Appl. Sci. 2018, 8(1), 139; https://doi.org/10.3390/app8010139 - 19 Jan 2018
Cited by 7 | Viewed by 3664
Abstract
The remarkable ability of humans to perform jump maneuvers greatly contributes to the improvements of the obstacle negotiation ability of humans. The paper proposes a jumping control scheme for a bipedal robot to perform a high jump. The half-body of the robot is [...] Read more.
The remarkable ability of humans to perform jump maneuvers greatly contributes to the improvements of the obstacle negotiation ability of humans. The paper proposes a jumping control scheme for a bipedal robot to perform a high jump. The half-body of the robot is modeled as three planar links and the motion during the launching phase is taken into account. A geometrically simple motion was first conducted through which the gear reduction ratio that matches the maximum motor output for high jumping was selected. Then, the following strategies to further exploit the motor output performance was examined: (1) to set the maximum torque of each joint as the baseline that is explicitly modeled as a piecewise linear function dependent on the joint angular velocity; (2) to exert it with a correction of the joint angular accelerations in order to satisfy some balancing criteria during the motion. The criteria include the location of ZMP (zero moment point) and the torque limit. Using the technique described above, the jumping pattern is pre-calculated to maximize the jump height. Finally, the effectiveness of the proposed method is evaluated through simulations. In the simulation, the bipedal robot model achieved a 0.477-m high jump. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Transition Analysis and Its Application to Global Path Determination for a Biped Climbing Robot
Appl. Sci. 2018, 8(1), 122; https://doi.org/10.3390/app8010122 - 16 Jan 2018
Cited by 8 | Viewed by 1950
Abstract
Biped climbing robots are considered good assistants and (or) substitutes for human workers carrying out high-rise truss-associated routine tasks. Flexible locomotion on three-dimensional complex trusses is a fundamental skill for these robots. In particular, the capability to transit from one structural member to [...] Read more.
Biped climbing robots are considered good assistants and (or) substitutes for human workers carrying out high-rise truss-associated routine tasks. Flexible locomotion on three-dimensional complex trusses is a fundamental skill for these robots. In particular, the capability to transit from one structural member to another is paramount for switching objects to be climbed upon. In this paper, we study member-to-member transition and its utility in global path searching for biped climbing robots. To compute operational regions for transition, hierarchical inspection of safety, reachability, and accessibility of grips is taken into account. A novel global path rapid determination approach is subsequently proposed based on the transition analysis. This scheme is efficient for finding feasible routes with respect to the overall structural environment, which also benefits the subsequent grip and motion planning. Simulations are conducted with Climbot, our self-developed biped climbing robot, to verify the efficiency of the presented method. Results show that our proposed method is able to accurately determine the operational region for transition within tens of milliseconds and can obtain global paths within seconds in general. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Bio-Inspired Adhesive Footpad for Legged Robot Climbing under Reduced Gravity: Multiple Toes Facilitate Stable Attachment
Appl. Sci. 2018, 8(1), 114; https://doi.org/10.3390/app8010114 - 15 Jan 2018
Cited by 8 | Viewed by 2169
Abstract
This paper presents the design of a legged robot with gecko-mimicking mechanism and mushroom-shaped adhesive microstructure (MSAMS) that can climb surfaces under reduced gravity. The design principle, adhesion performance and roles of different toes of footpad are explored and discussed in this paper. [...] Read more.
This paper presents the design of a legged robot with gecko-mimicking mechanism and mushroom-shaped adhesive microstructure (MSAMS) that can climb surfaces under reduced gravity. The design principle, adhesion performance and roles of different toes of footpad are explored and discussed in this paper. The effect of the preload velocity, peeling velocity and thickness of backing layering on the reliability of the robot are investigated. Results show that pull-force is independent of preload velocity, while the peeling force is relying on peeling velocity, and the peel strength increased with the increasing thickness of the backing layer. The climbing experiments show that the robot can climb under mimic zero gravity by using multiple toes facilitating adhesion. The robot with new type of footpads also provides a good platform for testing different adhesive materials for the future space applications. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Locomotion Efficiency Optimization of Biologically Inspired Snake Robots
Appl. Sci. 2018, 8(1), 80; https://doi.org/10.3390/app8010080 - 09 Jan 2018
Cited by 14 | Viewed by 2467
Abstract
Snake robots constitute bio-inspired solutions that have been studied due to their ability to move in challenging environments where other types of robots, such as wheeled or legged robots, usually fail. In this paper, we consider both land-based and swimming snake robots. One [...] Read more.
Snake robots constitute bio-inspired solutions that have been studied due to their ability to move in challenging environments where other types of robots, such as wheeled or legged robots, usually fail. In this paper, we consider both land-based and swimming snake robots. One of the principal concerns of the bio-inspired snake robots is to increase the motion efficiency in terms of the forward speed by improving the locomotion methods. Furthermore, energy efficiency becomes a crucial challenge for this type of robots due to the importance of long-term autonomy of these systems. In this paper, we take into account both the minimization of the power consumption and the maximization of the achieved forward velocity in order to investigate the optimal gait parameters for bio-inspired snake robots using lateral undulation and eel-like motion patterns. We furthermore consider possible negative work effects in the calculation of average power consumption of underwater snake robots. To solve the multi-objective optimization problem, we propose transforming the two objective functions into a single one using a weighted-sum method. For different set of weight factors, Particle Swarm Optimization is applied and a set of optimal points is consequently obtained. Pareto fronts or trade-off curves are illustrated for both land-based and swimming snake robots with different numbers of links. Pareto fronts represent trade-offs between the objective functions. For example, how increasing the forward velocity results in increasing power consumption. Therefore, these curves are a very useful tool for the control and design of snake robots. The trade-off curve thus constitutes a very useful tool for both the control and design of bio-inspired snake robots. In particular, the operators or designers of bio-inspired snake robots can choose a Pareto optimal point based on the trade-off curve, given the preferred number of links on the robot. The optimal gait parameters for the robot control system design are then directly given both for land-based and underwater snake robots. Moreover, we are able to obtain some observations about the optimal values of the gait parameters, which provide very important insights for future control design of bio-inspired snake robots. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Upper-Body Control and Mechanism of Humanoids to Compensate for Angular Momentum in the Yaw Direction Based on Human Running
Appl. Sci. 2018, 8(1), 44; https://doi.org/10.3390/app8010044 - 03 Jan 2018
Cited by 11 | Viewed by 2529
Abstract
Many extant studies proposed various stabilizing control methods for humanoids during the stance phase while hopping and running. Although these methods contribute to stability during hopping and running, humanoid robots do not swing their legs rapidly during the flight phase to prevent rotation [...] Read more.
Many extant studies proposed various stabilizing control methods for humanoids during the stance phase while hopping and running. Although these methods contribute to stability during hopping and running, humanoid robots do not swing their legs rapidly during the flight phase to prevent rotation in the yaw direction. Humans utilize their torsos and arms when running to compensate for the angular momentum in the yaw direction generated by leg movement during the flight phase. In this study, we developed an angular momentum control method based on human motion for a humanoid upper body. The method involves calculation of the angular momentum generated by the movement of the humanoid legs and calculation of the torso and arm motions required to compensate for the angular momentum of the legs in the yaw direction. We also developed a humanoid upper-body mechanism having human link length and mass properties, using carbon-fiber-reinforced plastic and a symmetric structure for generating large angular momentum. The humanoid robot developed in this study could generate almost the same angular momentum as that of a human. Furthermore, when suspended in midair, the humanoid robot achieved angular momentum compensation in the yaw direction. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
A Bio-Inspired Control Strategy for Locomotion of a Quadruped Robot
Appl. Sci. 2018, 8(1), 56; https://doi.org/10.3390/app8010056 - 02 Jan 2018
Cited by 8 | Viewed by 3317
Abstract
In order to effectively plan the robot gaits and foot workspace trajectory (WT) synchronously, a novel biologically inspired control strategy for the locomotion of a quadruped robot based on central pattern generator—neural network—workspace trajectory (CPG-NN-WT) is presented in this paper. Firstly, a foot [...] Read more.
In order to effectively plan the robot gaits and foot workspace trajectory (WT) synchronously, a novel biologically inspired control strategy for the locomotion of a quadruped robot based on central pattern generator—neural network—workspace trajectory (CPG-NN-WT) is presented in this paper. Firstly, a foot WT is planned via the Denavit-Hartenberg (D-H) notation and the inverse kinematics, which has the advantages of low mechanical shock, smooth movement, and sleek trajectory. Then, an improved central pattern generator (CPG) based on Hopf oscillators is proposed in this paper for smooth gait planning. Finally, a neural network is designed and trained to convert the CPG output to the preplanned WT, which can make full use of the advantages of the CPG-based method in gait planning and the WT-based method in foot trajectory planning simultaneously. Furthermore, virtual prototype simulations and experiments with a real quadruped robot are presented to validate the effectiveness of the proposed control strategy. The results show that the gait of the quadruped robot can be controlled easily and effectively by the CPG with its internal parameters; meanwhile, the foot trajectory meets the preplanned WT well. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Omnidirectional Jump of a Legged Robot Based on the Behavior Mechanism of a Jumping Spider
Appl. Sci. 2018, 8(1), 51; https://doi.org/10.3390/app8010051 - 01 Jan 2018
Cited by 8 | Viewed by 3561
Abstract
To find a common approach for the development of an efficient system that is able to achieve an omnidirectional jump, a jumping kinematic of a legged robot is proposed based on the behavior mechanism of a jumping spider. To satisfy the diversity of [...] Read more.
To find a common approach for the development of an efficient system that is able to achieve an omnidirectional jump, a jumping kinematic of a legged robot is proposed based on the behavior mechanism of a jumping spider. To satisfy the diversity of motion forms in robot jumping, a kind of 4 degrees of freedom (4DoFs) mechanical leg is designed. Taking the change of joint angle as inspiration by observing the behavior of the jumping spider during the acceleration phase, a redundant constraint to solve the kinematic is obtained. A series of experiments on three types of jumping—vertical jumping, sideways jumping and forward jumping—is carried out, while the initial attitude and path planning of the robot is studied. The proposed jumping kinematic is verified on the legged robot experimental platform, and the added redundant constraint could be verified as being reasonable. The results indicate that the jumping robot could maintain stability and complete the planned task of jumping, and the proposed spider-inspired jumping strategy could easily achieve an omnidirectional jump, thus enabling the robot to avoid obstacles. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Swarming Behavior Emerging from the Uptake–Kinetics Feedback Control in a Plant-Root-Inspired Robot
Appl. Sci. 2018, 8(1), 47; https://doi.org/10.3390/app8010047 - 01 Jan 2018
Cited by 5 | Viewed by 2534
Abstract
This paper presents a plant root behavior-based approach to defining the control architecture of a plant-root-inspired robot, which is composed of three root-agents for nutrient uptake and one shoot-agent for nutrient redistribution. By taking inspiration and extracting key principles from the uptake of [...] Read more.
This paper presents a plant root behavior-based approach to defining the control architecture of a plant-root-inspired robot, which is composed of three root-agents for nutrient uptake and one shoot-agent for nutrient redistribution. By taking inspiration and extracting key principles from the uptake of nutrient, movements and communication strategies adopted by plant roots, we developed an uptake–kinetics feedback control for the robotic roots. Exploiting the proposed control, each root is able to regulate the growth direction, towards the nutrients that are most needed, and to adjust nutrient uptake, by decreasing the absorption rate of the most plentiful one. Results from computer simulations and implementation of the proposed control on the robotic platform, Plantoid, demonstrate an emergent swarming behavior aimed at optimizing the internal equilibrium among nutrients through the self-organization of the roots. Plant wellness is improved by dynamically adjusting nutrients priorities only according to local information without the need of a centralized unit delegated for wellness monitoring and task allocation among the agents. Thus, the root-agents can ideally and autonomously grow at the best speed, exploiting nutrient distribution and improving performance, in terms of exploration capabilities and exploitation of resources, with respect to the tropism-inspired control previously proposed by the same authors. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Germinal Center Optimization Applied to Neural Inverse Optimal Control for an All-Terrain Tracked Robot
Appl. Sci. 2018, 8(1), 31; https://doi.org/10.3390/app8010031 - 27 Dec 2017
Cited by 9 | Viewed by 2589
Abstract
Nowadays, there are several meta-heuristics algorithms which offer solutions for multi-variate optimization problems. These algorithms use a population of candidate solutions which explore the search space, where the leadership plays a big role in the exploration-exploitation equilibrium. In this work, we propose to [...] Read more.
Nowadays, there are several meta-heuristics algorithms which offer solutions for multi-variate optimization problems. These algorithms use a population of candidate solutions which explore the search space, where the leadership plays a big role in the exploration-exploitation equilibrium. In this work, we propose to use a Germinal Center Optimization algorithm (GCO) which implements temporal leadership through modeling a non-uniform competitive-based distribution for particle selection. GCO is used to find an optimal set of parameters for a neural inverse optimal control applied to all-terrain tracked robot. In the Neural Inverse Optimal Control (NIOC) scheme, a neural identifier, based on Recurrent High Orden Neural Network (RHONN) trained with an extended kalman filter algorithm, is used to obtain a model of the system, then, a control law is design using such model with the inverse optimal control approach. The RHONN identifier is developed without knowledge of the plant model or its parameters, on the other hand, the inverse optimal control is designed for tracking velocity references. Applicability of the proposed scheme is illustrated using simulations results as well as real-time experimental results with an all-terrain tracked robot. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
A Synthetic Nervous System Controls a Simulated Cockroach
Appl. Sci. 2018, 8(1), 6; https://doi.org/10.3390/app8010006 - 22 Dec 2017
Cited by 5 | Viewed by 2142
Abstract
The purpose of this work is to better understand how animals control locomotion. This knowledge can then be applied to neuromechanical design to produce more capable and adaptable robot locomotion. To test hypotheses about animal motor control, we model animals and their nervous [...] Read more.
The purpose of this work is to better understand how animals control locomotion. This knowledge can then be applied to neuromechanical design to produce more capable and adaptable robot locomotion. To test hypotheses about animal motor control, we model animals and their nervous systems with dynamical simulations, which we call synthetic nervous systems (SNS). However, one major challenge is picking parameter values that produce the intended dynamics. This paper presents a design process that solves this problem without the need for global optimization. We test this method by selecting parameter values for SimRoach2, a dynamical model of a cockroach. Each leg joint is actuated by an antagonistic pair of Hill muscles. A distributed SNS was designed based on pathways known to exist in insects, as well as hypothetical pathways that produced insect-like motion. Each joint’s controller was designed to function as a proportional-integral (PI) feedback loop and tuned with numerical optimization. Once tuned, SimRoach2 walks through a simulated environment, with several cockroach-like features. A model with such reliable low-level performance is necessary to investigate more sophisticated locomotion patterns in the future. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Grasping Claws of Bionic Climbing Robot for Rough Wall Surface: Modeling and Analysis
Appl. Sci. 2018, 8(1), 14; https://doi.org/10.3390/app8010014 - 22 Dec 2017
Cited by 5 | Viewed by 2648
Abstract
Aiming at the inspection of rough stone and concrete wall surfaces, a grasping module of cross-arranged claw is designed. It can attach onto rough wall surfaces by hooking or grasping walls. First, based on the interaction mechanism of hooks and rough wall surfaces, [...] Read more.
Aiming at the inspection of rough stone and concrete wall surfaces, a grasping module of cross-arranged claw is designed. It can attach onto rough wall surfaces by hooking or grasping walls. First, based on the interaction mechanism of hooks and rough wall surfaces, the hook structures in claw tips are developed. Then, the size of the hook tip is calculated and the failure mode is analyzed. The effectiveness and reliability of the mechanism are verified through simulation and finite element analysis. Afterwards, the prototype of the grasping module of claw is established to carry out grasping experiment on vibrating walls. Finally, the experimental results demonstrate that the proposed cross-arranged claw is able to stably grasp static wall surfaces and perform well in grasping vibrating walls, with certain anti-rollover capability. This research lays a foundation for future researches on wall climbing robots with vibrating rough wall surfaces. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Performance Evaluation of a Novel Propulsion System for the Spherical Underwater Robot (SURIII)
Appl. Sci. 2017, 7(11), 1196; https://doi.org/10.3390/app7111196 - 20 Nov 2017
Cited by 29 | Viewed by 2946
Abstract
This paper considers a novel propulsion system for the third-generation Spherical Underwater Robot (SURIII), the improved propulsion system is designed and analyzed to verify its increased stability compared to the second-generation Spherical Underwater Robot (SURII). With the new propulsion system, the robot is [...] Read more.
This paper considers a novel propulsion system for the third-generation Spherical Underwater Robot (SURIII), the improved propulsion system is designed and analyzed to verify its increased stability compared to the second-generation Spherical Underwater Robot (SURII). With the new propulsion system, the robot is not only symmetric on the X axis but also on the Y axis, which increases the flexibility of its movement. The new arrangement also reduces the space constraints of servomotors and vectored water-jet thrusters. This paper also aims to the hydrodynamic characteristic of the whole robot. According to the different situations of the surge and heave motion, two kinds of methods are used to calculate the drag coefficient for the SURIII. For surge motion, the drag coefficient can be determined by the Reynolds number. For heave motion, considering about the influences of edges and gaps of the SURIII, the drag coefficient needs to be calculated by the dynamic equation. In addition, the Computational Fluid Dynamics (CFD) simulation is carried out to estimate some parameters which cannot be measured. The pressure contours, velocity vectors and velocity streamlines for different motions are extracted from the post-processor in the CFD simulation. The drag coefficients of surge and heave motion are both calculated by the simulation results and compared with the chosen one by Reynolds number. Finally, an experiment is also conducted for measure the propulsive force of the multi-vectored water-jet thrusters by using a 6-DoF load cell. The experimental results demonstrate the propulsive force is better than a previous version. Thus, the propulsive performance is better than before. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Snake-Like Robot with Fusion Gait for High Environmental Adaptability: Design, Modeling, and Experiment
Appl. Sci. 2017, 7(11), 1133; https://doi.org/10.3390/app7111133 - 03 Nov 2017
Cited by 7 | Viewed by 2954
Abstract
A snake changes its gait to adapt to different environments. A snake-like robot that is able to perform as many or more gaits than a real-life snake has the potential to successfully adapt to a range of environments, similar to a real-life snake. [...] Read more.
A snake changes its gait to adapt to different environments. A snake-like robot that is able to perform as many or more gaits than a real-life snake has the potential to successfully adapt to a range of environments, similar to a real-life snake. However, only a few mechanisms in the current snake-like framework can perform common gaits. In this paper, a novel snake-like robot is developed to resolve this problem. A multi-gait is established and used as a reference for the articulation design. A non-snake-like mechanism with linear articulation is combined with the classical swing joint. A prototype is designed and constructed for verification and analysis. Two basic main gaits, namely, serpentine and rectilinear locomotion, are fused, and a novel obstacle-aided locomotion based on rectilinear motion is developed. The experiment demonstrates that the robot can generate all of the expected gaits with high movement efficiency. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Bio-Inspired Real-Time Prediction of Human Locomotion for Exoskeletal Robot Control
Appl. Sci. 2017, 7(11), 1130; https://doi.org/10.3390/app7111130 - 02 Nov 2017
Cited by 5 | Viewed by 2002
Abstract
Human motion detection is of fundamental importance for control of human–robot coupled systems such as exoskeletal robots. Inertial measurement units have been widely used for this purpose, although delay is a major challenge for inertial measurement unit-based motion capture systems. In this paper, [...] Read more.
Human motion detection is of fundamental importance for control of human–robot coupled systems such as exoskeletal robots. Inertial measurement units have been widely used for this purpose, although delay is a major challenge for inertial measurement unit-based motion capture systems. In this paper, we use previous and current inertial measurement unit readings to predict human locomotion based on their kinematic properties. Human locomotion is a synergetic process of the musculoskeletal system characterized by smoothness, high nonlinearity, and quasi-periodicity. Takens’ reconstruction method can well characterize quasi-periodicity and nonlinear systems. With Takens’ reconstruction framework, we developed improving methods, including Gaussian coefficient weighting and offset correction (which is based on the smoothness of human locomotion), Kalman fusion with complementary joint data prediction and united source of historical embedding generation (which is synergy-inspired), and Kalman fusion with the Newton-based method with a velocity and acceleration high-gain observer (also based on smoothness). After thorough analysis of the parameters and the effect of these improving techniques, we propose a novel prediction method that possesses the combined advantages of parameter robustness, high accuracy, trajectory smoothness, zero dead time, and adaptability to irregularities. The proposed methods were tested and validated by experiments, and the real-time applicability in a human locomotion capture system was also validated. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Numerical Simulation of an Oscillatory-Type Tidal Current Powered Generator Based on Robotic Fish Technology
Appl. Sci. 2017, 7(10), 1070; https://doi.org/10.3390/app7101070 - 16 Oct 2017
Cited by 2 | Viewed by 2330
Abstract
The generation of clean renewable energy is becoming increasingly critical, as pollution and global warming threaten the environment in which we live. While there are many different kinds of natural energy that can be harnessed, marine tidal energy offers reliability and predictability. However, [...] Read more.
The generation of clean renewable energy is becoming increasingly critical, as pollution and global warming threaten the environment in which we live. While there are many different kinds of natural energy that can be harnessed, marine tidal energy offers reliability and predictability. However, harnessing energy from tidal flows is inherently difficult, due to the harsh environment. Current mechanisms used to harness tidal flows center around propeller-based solutions but are particularly prone to failure due to marine fouling from such as encrustations and seaweed entanglement and the corrosion that naturally occurs in sea water. In order to efficiently harness tidal flow energy in a cost-efficient manner, development of a mechanism that is inherently resistant to these harsh conditions is required. One such mechanism is a simple oscillatory-type mechanism based on robotic fish tail fin technology. This uses the physical phenomenon of vortex-induced oscillation, in which water currents flowing around an object induce transverse motion. We consider two specific types of oscillators, firstly a wing-type oscillator, in which the optimal elastic modulus is being sort. Secondly, the optimal selection of shape from 6 basic shapes for a reciprocating oscillating head-type oscillator. A numerical analysis tool for fluid structure-coupled problems—ANSYS—was used to select the optimum softness of material for the first type of oscillator and the best shape for the second type of oscillator, based on the exhibition of high lift coefficients. For a wing-type oscillator, an optimum elastic modulus for an air-foil was found. For a self-induced vibration-type mechanism, based on analysis of vorticity and velocity distribution, a square-shaped head exhibited a lift coefficient of more than two times that of a cylindrically shaped head. Analysis of the flow field clearly showed that the discontinuous flow caused by a square-headed oscillator results in higher lift coefficients due to intense vortex shedding, and that stable operation can be achieved by selecting the optimum length to width ratio. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Parameters Sensitivity Analysis of Position-Based Impedance Control for Bionic Legged Robots’ HDU
Appl. Sci. 2017, 7(10), 1035; https://doi.org/10.3390/app7101035 - 10 Oct 2017
Cited by 16 | Viewed by 2723
Abstract
For the hydraulic drive unit (HDU) on the joints of bionic legged robots, this paper proposes the position-based impedance control method. Then, the impedance control performance is tested by a HDU performance test platform. Further, the method of first-order sensitivity matrix is proposed [...] Read more.
For the hydraulic drive unit (HDU) on the joints of bionic legged robots, this paper proposes the position-based impedance control method. Then, the impedance control performance is tested by a HDU performance test platform. Further, the method of first-order sensitivity matrix is proposed to analyze the dynamic sensitivity of four main control parameters under four working conditions. To research the parameter sensitivity quantificationally, two sensitivity indexes are defined, and the sensitivity analysis results are verified by experiments. The results of the experiments show that, when combined with corresponding optimization strategies, the dynamic compliance composition theory and the results from sensitivity analysis can compensate for the control parameters and optimize the control performance in different working conditions. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Design and Experimental Development of a Pneumatic Stiffness Adjustable Foot System for Biped Robots Adaptable to Bumps on the Ground
Appl. Sci. 2017, 7(10), 1005; https://doi.org/10.3390/app7101005 - 29 Sep 2017
Cited by 4 | Viewed by 2007
Abstract
Walking on rough terrains still remains a challenge that needs to be addressed for biped robots because the unevenness on the ground can easily disrupt the walking stability. This paper proposes a novel foot system with passively adjustable stiffness for biped robots which [...] Read more.
Walking on rough terrains still remains a challenge that needs to be addressed for biped robots because the unevenness on the ground can easily disrupt the walking stability. This paper proposes a novel foot system with passively adjustable stiffness for biped robots which is adaptable to small-sized bumps on the ground. The robotic foot is developed by attaching eight pneumatic variable stiffness units to the sole separately and symmetrically. Each variable stiffness unit mainly consists of a pneumatic bladder and a mechanical reversing valve. When walking on rough ground, the pneumatic bladders in contact with bumps are compressed, and the corresponding reversing valves are triggered to expel out the air, enabling the pneumatic bladders to adapt to the bumps with low stiffness; while the other pneumatic bladders remain rigid and maintain stable contact with the ground, providing support to the biped robot. The performances of the proposed foot system, including the variable stiffness mechanism, the adaptability on the bumps of different heights, and the application on a biped robot prototype are demonstrated by various experiments. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
A Precise Positioning Method for a Puncture Robot Based on a PSO-Optimized BP Neural Network Algorithm
Appl. Sci. 2017, 7(10), 969; https://doi.org/10.3390/app7100969 - 21 Sep 2017
Cited by 36 | Viewed by 3506
Abstract
The problem of inverse kinematics is fundamental in robot control. Many traditional inverse kinematics solutions, such as geometry, iteration, and algebraic methods, are inadequate in high-speed solutions and accurate positioning. In recent years, the problem of robot inverse kinematics based on neural networks [...] Read more.
The problem of inverse kinematics is fundamental in robot control. Many traditional inverse kinematics solutions, such as geometry, iteration, and algebraic methods, are inadequate in high-speed solutions and accurate positioning. In recent years, the problem of robot inverse kinematics based on neural networks has received extensive attention, but its precision control is convenient and needs to be improved. This paper studies a particle swarm optimization (PSO) back propagation (BP) neural network algorithm to solve the inverse kinematics problem of a UR3 robot based on six degrees of freedom, overcoming some disadvantages of BP neural networks. The BP neural network improves the convergence precision, convergence speed, and generalization ability. The results show that the position error is solved by the research method with respect to the UR3 robot inverse kinematics with the joint angle less than 0.1 degrees and the output end tool less than 0.1 mm, achieving the required positioning for medical puncture surgery, which demands precise positioning of the robot to less than 1 mm. Aiming at the precise application of the puncturing robot, the preliminary experiment has been conducted and the preliminary results have been obtained, which lays the foundation for the popularization of the robot in the medical field. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Model-Based Design and Evaluation of a Brachiating Monkey Robot with an Active Waist
Appl. Sci. 2017, 7(9), 947; https://doi.org/10.3390/app7090947 - 14 Sep 2017
Cited by 2 | Viewed by 2342
Abstract
We report on the model-based development of a monkey robot that is capable of performing continuous brachiation locomotion on swingable rod, as the intermediate step toward studying brachiation on the soft rope or on horizontal ropes with both ends fixed. The work is [...] Read more.
We report on the model-based development of a monkey robot that is capable of performing continuous brachiation locomotion on swingable rod, as the intermediate step toward studying brachiation on the soft rope or on horizontal ropes with both ends fixed. The work is different from other previous works where the model or the robot swings on fixed bars. The model, which is composed of two rigid links, was inspired by the dynamic motion of primates. The model further served as the design guideline for a robot that has five degree of freedoms: two on each arm for rod changing and one on the waist to initiate a swing motion. The model was quantitatively formulated, and its dynamic behavior was analyzed in simulation. Further, a two-stage controller was developed within the simulation environment, where the first stage used the natural dynamics of a two-link pendulum-like model, and the second stage used the angular velocity feedback to regulate the waist motion. Finally, the robot was empirically built and evaluated. The experimental results confirm that the robot can perform model-like swing behavior and continuous brachiation locomotion on rods. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Data-Foraging-Oriented Reconnaissance Based on Bio-Inspired Indirect Communication for Aerial Vehicles
Appl. Sci. 2017, 7(7), 729; https://doi.org/10.3390/app7070729 - 16 Jul 2017
Cited by 2 | Viewed by 2312
Abstract
In recent years, aerial vehicles have allowed exploring scenarios with harsh conditions. These can conduct reconnaissance tasks in areas that change periodically and have a high spatial and temporal resolution. The objective of a reconnaissance task is to survey an area and retrieve [...] Read more.
In recent years, aerial vehicles have allowed exploring scenarios with harsh conditions. These can conduct reconnaissance tasks in areas that change periodically and have a high spatial and temporal resolution. The objective of a reconnaissance task is to survey an area and retrieve strategic information. The aerial vehicles, however, have inherent constraints in terms of energy and transmission range due to their mobility. Despite these constraints, the Data Foraging problem requires the aerial vehicles to exchange information about profitable data sources. In Data Foraging, establishing a single path is not viable because of dynamic conditions of the environment. Thus, reconnaissance must be focused on periodically searching profitable environmental data sources, as some animals perform foraging. In this work, a data-foraging-oriented reconnaissance algorithm based on bio-inspired indirect communication for aerial vehicles is presented. The approach establishes several paths that overlap to identify valuable data sources. Inspired by the stigmergy principle, the aerial vehicles indirectly communicate through artificial pheromones. The aerial vehicles traverse the environment using a heuristic algorithm that uses the artificial pheromones as feedback. The solution is formally defined and mathematically evaluated. In addition, we show the viability of the algorithm by simulations which have been tested through various statistical hypothesis. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Calculation of the Center of Mass Position of Each Link of Multibody Biped Robots
Appl. Sci. 2017, 7(7), 724; https://doi.org/10.3390/app7070724 - 14 Jul 2017
Cited by 4 | Viewed by 2204
Abstract
In this paper, a novel method to determine the center of mass position of each link of human-like multibody biped robots is proposed. A first formulation to determine the total center of mass position has been tested in other works on a biped [...] Read more.
In this paper, a novel method to determine the center of mass position of each link of human-like multibody biped robots is proposed. A first formulation to determine the total center of mass position has been tested in other works on a biped platform with human-like dimensions. In this paper, the formulation is optimized and extended, and it is able to give as output the center of mass positions of each link of the platform. The calculation can be applied to different types of robots. The optimized formulation is validated using a simulated biped robot in MATLAB. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Article
Human-Like Walking with Heel Off and Toe Support for Biped Robot
Appl. Sci. 2017, 7(5), 499; https://doi.org/10.3390/app7050499 - 18 May 2017
Cited by 5 | Viewed by 4038
Abstract
The under-actuated foot rotation that the heel of the stance leg lifts off the ground and the body rotates around the stance toe is an important feature in human walking. However, it is absent in the realized walking gait for the majority of [...] Read more.
The under-actuated foot rotation that the heel of the stance leg lifts off the ground and the body rotates around the stance toe is an important feature in human walking. However, it is absent in the realized walking gait for the majority of biped robots because of the difficulty and complexity in the control it brings about. In this paper, a hybrid control approach aiming to integrate the main characteristics of human walking into a simulated seven-link biped robot is presented and then verified with simulations. The bipedal robotic gait includes a fully actuated single support phase with the stance heel supporting the body, an under-actuated single support phase, with the stance toe supporting the body, and an instantaneous double support phase when the two legs exchange their roles. The walking controller combines virtual force control and foot placement control, which are applied to the stance leg and the swing leg, respectively. The virtual force control assumes that there is a virtual force which can generate the desired torso motion on the center of mass of the torso link, and then the virtual force is applied through the real torques on each actuated joint of the stance leg to create the same effect that the virtual force would have created. The foot placement control uses a path tracking controller to follow the predefined trajectory of the swing foot when walking forward. The trajectories of the torso and the swing foot are generated based on the cart-cable model. Co-simulations in Adams and MATLAB show that the desired gait is achieved with a biped robot under the action of the proposed method. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Review

Jump to: Editorial, Research

Review
State of the Art: Bipedal Robots for Lower Limb Rehabilitation
Appl. Sci. 2017, 7(11), 1182; https://doi.org/10.3390/app7111182 - 16 Nov 2017
Cited by 10 | Viewed by 3603
Abstract
The bipedal robot is one of the most attractive robots types given its similarity to the locomotion of human beings and its ability to assist people to walk during rehabilitation. This review summarizes the chronological historical development of bipedal robots and introduces some [...] Read more.
The bipedal robot is one of the most attractive robots types given its similarity to the locomotion of human beings and its ability to assist people to walk during rehabilitation. This review summarizes the chronological historical development of bipedal robots and introduces some current popular bipedal robots age. Then, the basic theory-stability control and key technology-motion planning of bipedal robots are introduced and analyzed. Bipedal robots have a wide range of applications in the service, education, entertainment, and other industries. After that, we specifically discuss the applications of bipedal robots in lower limb rehabilitation, including wearable exoskeleton robots, rehabilitation equipment, soft exoskeleton robots, and unpowered exoskeleton robots, and their control methods. Lastly, the future development and the challenges in this field are discussed. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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Review
Perception-Driven Obstacle-Aided Locomotion for Snake Robots: The State of the Art, Challenges and Possibilities
Appl. Sci. 2017, 7(4), 336; https://doi.org/10.3390/app7040336 - 29 Mar 2017
Cited by 31 | Viewed by 3628
Abstract
In nature, snakes can gracefully traverse a wide range of different and complex environments. Snake robots that can mimic this behaviour could be fitted with sensors and transport tools to hazardous or confined areas that other robots and humans are unable to access. [...] Read more.
In nature, snakes can gracefully traverse a wide range of different and complex environments. Snake robots that can mimic this behaviour could be fitted with sensors and transport tools to hazardous or confined areas that other robots and humans are unable to access. In order to carry out such tasks, snake robots must have a high degree of awareness of their surroundings (i.e., perception-driven locomotion) and be capable of efficient obstacle exploitation (i.e., obstacle-aided locomotion) to gain propulsion. These aspects are pivotal in order to realise the large variety of possible snake robot applications in real-life operations such as fire-fighting, industrial inspection, search-and-rescue, and more. In this paper, we survey and discuss the state of the art, challenges, and possibilities of perception-driven obstacle-aided locomotion for snake robots. To this end, different levels of autonomy are identified for snake robots and categorised into environmental complexity, mission complexity, and external system independence. From this perspective, we present a step-wise approach on how to increment snake robot abilities within guidance, navigation, and control in order to target the different levels of autonomy. Pertinent to snake robots, we focus on current strategies for snake robot locomotion in the presence of obstacles. Moreover, we put obstacle-aided locomotion into the context of perception and mapping. Finally, we present an overview of relevant key technologies and methods within environment perception, mapping, and representation that constitute important aspects of perception-driven obstacle-aided locomotion. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics)
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