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29 pages, 25453 KiB

Open AccessArticle

Design and Implementation of a Lizard-Inspired Robot

by Shunsuke Nansai, Yuki Ando, Hiroshi Itoh and Norihiro Kamamichi

Appl. Sci. 2021, 11(17), 7898; https://0-doi-org.brum.beds.ac.uk/10.3390/app11177898 - 27 Aug 2021

Cited by 3 | Viewed by 2084

The purpose of this paper is to design a lizard-inspired robot driven by a single actuator. Lizard-inspired robots in previous studies had the issue of slippage of their supporting legs. To overcome this issue, a lizard-inspired robot consisting of a four-bar linkage mechanism [...] Read more.

The purpose of this paper is to design a lizard-inspired robot driven by a single actuator. Lizard-inspired robots in previous studies had the issue of slippage of their supporting legs. To overcome this issue, a lizard-inspired robot consisting of a four-bar linkage mechanism was designed. The purpose of this paper was achieved through three processes. The first process was kinematic analysis, where the turning angle and stride length of the robot were analyzed. The kinematic analysis results were verified via numerical simulations. The second process was the design and fabrication of the robot. For the robot’s design, both a shuffle-walking method utilizing a claw-shaped leg mechanism and a sliding-rod mechanism for equipping the actuator on the robot’s own coordinates were designed. The third process was experimental verification. The first experimental result was that the claw-shaped leg mechanism was capable of generating an 85.26 N difference in the static frictional force in the longitudinal direction. The other three experimental results were that the robot was capable of driving with 3.51%, 3.16%, and 3.53% error compared to the kinematic analyses, respectively. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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16 pages, 23385 KiB

Open AccessArticle

Compliant Detachment of Wall-Climbing Robot Unaffected by Adhesion State

by Bingcheng Wang, Xiaofeng Xiong, Jinjun Duan, Zhouyi Wang and Zhendong Dai

Appl. Sci. 2021, 11(13), 5860; https://0-doi-org.brum.beds.ac.uk/10.3390/app11135860 - 24 Jun 2021

Cited by 9 | Viewed by 2139

Abstract

Adhesion state is a key factor affecting the motion stability of a wall-climbing robot. According to different adhesion states, there is no universal method for compliant detachment. We propose an online impedance strategy for controlling peeling angle to realize compliant movement. Variable compliant [...] Read more.

Adhesion state is a key factor affecting the motion stability of a wall-climbing robot. According to different adhesion states, there is no universal method for compliant detachment. We propose an online impedance strategy for controlling peeling angle to realize compliant movement. Variable compliant motions are achieved by online tuning the stiffness and damping parameters of proportional-derivative control, which realizes compliant detachment with a peeling angle of

π

, the adhesion strength to adjust to a minimum and basically eliminated the instant change in normal adhesion strength at the detachment end state. The proposed controller was validated using a vertical climbing robot. The results showed that, with the proposed controller, the sudden change in the normal adhesion force during peeling was significantly reduced. Besides, there is no correlation between the sudden change in the normal adhesion force at the detachment end state and the adhesion state. Regardless of the adhesion states, the compliant detachment can be accomplished reliably. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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17 pages, 3781 KiB

Open AccessArticle

Design, Optimization and Evaluation of a New Cylinder Attachment Geometry to Improve the Hopping Height of the Bionic One-Legged Robot

by Donglai Zhao, Wenjie Ge, Xiaojuan Mo, Yuzhu Li and Zhuo Wang

Appl. Sci. 2021, 11(8), 3676; https://0-doi-org.brum.beds.ac.uk/10.3390/app11083676 - 19 Apr 2021

Viewed by 3027

Abstract

Due to the high power-to-weight ratio and robustness, hydraulic cylinders are widely used in the actuation area of the legged robot systems. Most of these applications are focused on the motion stability, gait planning, and impedance control. However, the energy efficiency of the [...] Read more.

Due to the high power-to-weight ratio and robustness, hydraulic cylinders are widely used in the actuation area of the legged robot systems. Most of these applications are focused on the motion stability, gait planning, and impedance control. However, the energy efficiency of the legged robotic system is also a very important point to be considered. Hopping locomotion requires a fast extension of the tibia leg at the end of the take-off phase, which causes a continuous increment of the cylinder velocity under the normally direct attachment geometry (DAG) of the cylinder. This leads to a high flow requirement, large pressure drop, and low energy efficiency. Therefore, we propose a four-bar mechanism attachment geometry (FMAG) to improve the energy efficiency by refining the relationship between the joint angle and cylinder displacement trend. The kinematic and dynamic models of the bionic one-legged robot are built to calculate the hopping process during the take-off phase. Based on the established dynamic models, the design parameters in both the DAG and FMAG are optimized to maximize the hopping height, respectively. The hopping experiments are conducted to verify the effectiveness of the new attachment geometry. The experimental results show that the robot hopping energy at the end of the take-off phase increases 14.8% under the FMAG. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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25 pages, 2221 KiB

Open AccessFeature PaperArticle

Wankelmut: A Simple Benchmark for the Evolvability of Behavioral Complexity

by Thomas Schmickl, Payam Zahadat and Heiko Hamann

Appl. Sci. 2021, 11(5), 1994; https://0-doi-org.brum.beds.ac.uk/10.3390/app11051994 - 24 Feb 2021

Cited by 1 | Viewed by 1675

Abstract

In evolutionary robotics, an encoding of the control software that maps sensor data (input) to motor control values (output) is shaped by stochastic optimization methods to complete a predefined task. This approach is assumed to be beneficial compared to standard methods of controller [...] Read more.

In evolutionary robotics, an encoding of the control software that maps sensor data (input) to motor control values (output) is shaped by stochastic optimization methods to complete a predefined task. This approach is assumed to be beneficial compared to standard methods of controller design in those cases where no a priori model is available that could help to optimize performance. For robots that have to operate in unpredictable environments as well, an evolutionary robotics approach is favorable. We present here a simple-to-implement, but hard-to-pass benchmark to allow for quantifying the “evolvability” of such evolving robot control software towards increasing behavioral complexity. We demonstrate that such a model-free approach is not a free lunch, as already simple tasks can be unsolvable barriers for fully open-ended uninformed evolutionary computation techniques. We propose the “Wankelmut” task as an objective for an evolutionary approach that starts from scratch without pre-shaped controller software or any other informed approach that would force the behavior to be evolved in a desired way. Our main claim is that “Wankelmut” represents the simplest set of problems that makes plain-vanilla evolutionary computation fail. We demonstrate this by a series of simple standard evolutionary approaches using different fitness functions and standard artificial neural networks, as well as continuous-time recurrent neural networks. All our tested approaches failed. From our observations, we conclude that other evolutionary approaches will also fail if they do not per se favor or enforce the modularity of the evolved structures and if they do not freeze or protect already evolved functionalities from being destroyed again in the later evolutionary process. However, such a protection would require a priori knowledge of the solution of the task and contradict the “no a priori model” approach that is often claimed in evolutionary computation. Thus, we propose a hard-to-pass benchmark in order to make a strong statement for self-complexifying and generative approaches in evolutionary computation in general and in evolutionary robotics specifically. We anticipate that defining such a benchmark by seeking the simplest task that causes the evolutionary process to fail can be a valuable benchmark for promoting future development in the fields of artificial intelligence, evolutionary robotics, and artificial life. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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16 pages, 7044 KiB

Open AccessArticle

Controllable Height Hopping of a Parallel Legged Robot

by Zewen He, Fei Meng, Xuechao Chen, Zhangguo Yu, Xuxiao Fan, Ryuki Sato, Aiguo Ming and Qiang Huang

Appl. Sci. 2021, 11(4), 1421; https://0-doi-org.brum.beds.ac.uk/10.3390/app11041421 - 04 Feb 2021

Cited by 8 | Viewed by 2507

Abstract

Legged robots imitating animals have become versatile and applicable in more application scenarios recent years. Most of their functions rely on powerful athletic abilities, which require the robots to have remarkable actuator capacities and controllable dynamic performance. In most experimental demonstrations, continuous hopping [...] Read more.

Legged robots imitating animals have become versatile and applicable in more application scenarios recent years. Most of their functions rely on powerful athletic abilities, which require the robots to have remarkable actuator capacities and controllable dynamic performance. In most experimental demonstrations, continuous hopping at a desired height is a basic required motion for legged robots to verify their athletic ability. However, recent legged robots have limited ability in balance of high torque output and actuator transparency and appropriate structure size at the same time. Therefore, in our research, we developed a parallel robot leg using a brushless direct current motor combined with a harmonic driver, without extra force or torque sensor feedback, which uses virtual model control (VMC) to realize active compliance on the leg, and a whole-leg control system with dynamics modeling and parameter optimization for continuous vertical hopping at a desired height. In our experiments, the robot was able to maintain stability during vertical hopping while following a variable reference height in various ground situations. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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14 pages, 4016 KiB

Open AccessArticle

Mechanical Design of a Bioinspired Compliant Robotic Wrist Rehabilitation Equipment

by Ovidiu Filip, Andrea Deaconescu and Tudor Deaconescu

Appl. Sci. 2021, 11(3), 1246; https://0-doi-org.brum.beds.ac.uk/10.3390/app11031246 - 29 Jan 2021

Cited by 2 | Viewed by 2494

Abstract

Early social reintegration of patients with disabilities of the wrist is possible with the help of dedicated rehabilitation equipment. Using such equipment reduces the duration of recovery and reduces significantly rehabilitation costs. Based on these considerations the paper puts forward a novel constructive [...] Read more.

Early social reintegration of patients with disabilities of the wrist is possible with the help of dedicated rehabilitation equipment. Using such equipment reduces the duration of recovery and reduces significantly rehabilitation costs. Based on these considerations the paper puts forward a novel constructive solution of rehabilitation equipment that ensures the simultaneous passive mobilization of the radiocarpal, metacarpophalangeal, and interphalangeal joints. The novelty of this equipment consists in the bioinspired concept of the hand support based on the Fin-Ray effect and in driving it by means of a pneumatic muscle, an inherently compliant actuator. The paper places an emphasis on the compliant character of the rehabilitation equipment that is responsible for its adaptability to the concrete conditions of patient pain tolerability. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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Review

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44 pages, 6161 KiB

Open AccessReview

Towards Bio-Hybrid Energy Harvesting in the Real-World: Pushing the Boundaries of Technologies and Strategies Using Bio-Electrochemical and Bio-Mechanical Processes

by Abanti Shama Afroz, Donato Romano, Francesco Inglese and Cesare Stefanini

Appl. Sci. 2021, 11(5), 2220; https://0-doi-org.brum.beds.ac.uk/10.3390/app11052220 - 03 Mar 2021

Cited by 11 | Viewed by 3950

Abstract

Sustainable, green energy harvesting has gained a considerable amount of attention over the last few decades and within its vast field of resources, bio-energy harvesters have become promising. These bio-energy harvesters appear in a wide variety and function either by directly generating energy [...] Read more.

Sustainable, green energy harvesting has gained a considerable amount of attention over the last few decades and within its vast field of resources, bio-energy harvesters have become promising. These bio-energy harvesters appear in a wide variety and function either by directly generating energy with mechanisms similar to living organisms or indirectly by extracting energy from living organisms. Presently this new generation of energy harvesters is fueling various low-power electronic devices while being extensively researched for large-scale applications. In this review we concentrate on recent progresses of the three promising bio-energy harvesters: microbial fuel cells, enzyme-based fuel cells and biomechanical energy harvesters. All three of these technologies are already extensively being used in small-scale applications. While microbial fuel cells hold immense potential in industrial-scale energy production, both enzyme-based fuel cells and biomechanical energy harvesters show promises of becoming independent and natural power sources for wearable and implantable devices for many living organisms including humans. Herein, we summarize the basic principles of these bio-energy harvesting technologies, outline their recent advancements and estimate the near future research trends. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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38 pages, 4186 KiB

Open AccessReview

Jumping Locomotion Strategies: From Animals to Bioinspired Robots

by Xiaojuan Mo, Wenjie Ge, Marco Miraglia, Francesco Inglese, Donglai Zhao, Cesare Stefanini and Donato Romano

Appl. Sci. 2020, 10(23), 8607; https://0-doi-org.brum.beds.ac.uk/10.3390/app10238607 - 01 Dec 2020

Cited by 26 | Viewed by 11522

Abstract

Jumping is a locomotion strategy widely evolved in both invertebrates and vertebrates. In addition to terrestrial animals, several aquatic animals are also able to jump in their specific environments. In this paper, the state of the art of jumping robots has been systematically [...] Read more.

Jumping is a locomotion strategy widely evolved in both invertebrates and vertebrates. In addition to terrestrial animals, several aquatic animals are also able to jump in their specific environments. In this paper, the state of the art of jumping robots has been systematically analyzed, based on their biological model, including invertebrates (e.g., jumping spiders, locusts, fleas, crickets, cockroaches, froghoppers and leafhoppers), vertebrates (e.g., frogs, galagoes, kangaroos, humans, dogs), as well as aquatic animals (e.g., both invertebrates and vertebrates, such as crabs, water-striders, and dolphins). The strategies adopted by animals and robots to control the jump (e.g., take-off angle, take-off direction, take-off velocity and take-off stability), aerial righting, land buffering, and resetting are concluded and compared. Based on this, the developmental trends of bioinspired jumping robots are predicted. Full article

(This article belongs to the Special Issue Biorobotics and Bionic Systems)

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