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16 pages, 8312 KiB

Open AccessArticle

3D-Printed Soft Bionic Inchworm Robot Powered by Magnetic Force

by Deli Xia, Luying Zhang, Weihang Nong, Qingshan Duan and Jiang Ding

Biomimetics 2025, 10(4), 202; https://doi.org/10.3390/biomimetics10040202 - 26 Mar 2025

Viewed by 286

Abstract

Based on soft body structure and unique gait of bending and stretching, Soft Bionic Inchworm Robots (SBIRs) are used in pipeline inspection and terrain exploration. Many existing SBIRs rely on complex production mechanisms and are cable-driven, which hinders rapid production and smooth movement [...] Read more.

Based on soft body structure and unique gait of bending and stretching, Soft Bionic Inchworm Robots (SBIRs) are used in pipeline inspection and terrain exploration. Many existing SBIRs rely on complex production mechanisms and are cable-driven, which hinders rapid production and smooth movement through complex environments, respectively. To address these challenges, this paper introduces a 3D-printed SBIR, featuring a 3D-printed body actuated by magnetic forces. We introduce the design and production process of the 3D-SBIR and analyze its motion gait. Subsequently, the material composition model and bending deformation model of the robot are developed based on the theory of hyper-elastic materials. The accuracy of the model is validated using simulation analysis and experimental testing of the robot. Meanwhile, we carry out a magnetic simulation analysis and discuss the factors influencing the size of the magnetic force. Finally, a series of experiments are conducted to prove the excellent locomotion capability of the robot. The 3D-SBIR demonstrates remarkable flexibility and multimodal movement capabilities. It can navigate through narrow curved passages with ease, passively overcome obstacles, climb steps up to 0.8 times its body height, and perform a seamless transition while moving across a horizontal plane onto a vertical plane. The 3D-SBIR proposed in this paper is characterized by rapid production, cable-free actuation, and multimodal motion capabilities, making it well suited for moving in unstructured environments. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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20 pages, 22785 KiB

Open AccessArticle

A Computational Study on the Hydrodynamics of Bio-Inspired Quadrupedal Paddling

by Yihan Wang, Yumeng Cai, Bin Xie, Chi Zhu, Yunquan Li and Ye Chen

Biomimetics 2025, 10(3), 148; https://doi.org/10.3390/biomimetics10030148 - 27 Feb 2025

Viewed by 484

Abstract

Due to its exceptional terrain mobility, quadrupedal locomotion has been used in the design of many amphibious robots for broad applications including resource exploration, disaster rescue, and reconnaissance. In this work, swimming of a quadrupedal paddling model is considered, and the effects of [...] Read more.

Due to its exceptional terrain mobility, quadrupedal locomotion has been used in the design of many amphibious robots for broad applications including resource exploration, disaster rescue, and reconnaissance. In this work, swimming of a quadrupedal paddling model is considered, and the effects of the legs’ initial swing angle, swing amplitude, and power phase duration are numerically investigated through three paddling gaits, namely, the trotting gait, the diagonal, and the lateral sequence gaits. Three different modes for drag-based thrust generation, the “Trotting Mode”, the “Hindering Mode”, and the “Separate Mode”, are identified. In the “Trotting Mode”, each pair of diagonal legs contributes equally and alternately to the thrust within the paddling cycle, and its contribution is impaired by the other pair of diagonal legs. In the “Hindering Mode”, the thrust contribution of an individual leg is significantly undermined by the drag resulting from the preceding leg leaving its current power phase and entering the following recovery phase. In the “Separate Mode”, the four legs independently contribute to the total thrust by forming a compact four-peak waveform equally distributed within one paddling cycle. At a given swing amplitude, the leg configuration at peak thrust moment is identical, regardless of initial swing angle and power phase ratio. Meanwhile, a forward-tilted leg configuration with flatter upper- and lower-limb alignment at peak thrust moment consistently indicates a lower thrust generation. Hydrodynamic moments in the diagonal and lateral sequence gaits are much larger than those in the trotting gait. In addition, enhanced thrust is typically accompanied by larger hydrodynamic moments and a higher energy expenditure. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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21 pages, 7490 KiB

Open AccessArticle

Development of a Wire-Driven Robotic Fish Based on Double Sine Mechanism

by Qian Yang, Qixin Wang, Zihao Cao, Zeyue Zhao, Ye Chen and Yong Zhong

Biomimetics 2025, 10(3), 136; https://doi.org/10.3390/biomimetics10030136 - 24 Feb 2025

Viewed by 513

Abstract

Wire-driven robotic fish can effectively simulate the movement of real fish, but research on high-frequency wire-driven robotic fish is limited. This paper introduces the development of wire-driven robotic fish based on a double-sine mechanism. The appearance of the fish body is designed based [...] Read more.

Wire-driven robotic fish can effectively simulate the movement of real fish, but research on high-frequency wire-driven robotic fish is limited. This paper introduces the development of wire-driven robotic fish based on a double-sine mechanism. The appearance of the fish body is designed based on the morphology of tuna, and a mechanism that can support the high-frequency movement of the wire-driven mechanism is designed. The swimming speed and turning performance of the robotic fish are experimentally tested at various swing frequencies. The experimental results show that within the range of 1 to 4 Hz, the swimming speed of the robotic fish with different tail stiffness increases as the frequency increases. However, when the frequency exceeds 4 Hz, the swimming speed decreases. The tail joint with lower stiffness performs better at low frequencies, but as frequency increases, higher stiffness results in better swimming performance. Experimental tests show that the turning radius increases with higher swing frequencies and lower stiffness, resulting in a larger turning radius. This experiment will help to improve the application of high-frequency wire-driven mechanisms in the study of robot fish movement and carry out more in-depth bionic research in the future. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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23 pages, 13204 KiB

Open AccessArticle

A Pneumatic Soft Glove System Based on Bidirectional Bending Functionality for Rehabilitation

by Xiaohui Wang, Qinkun Cheng, Zhifeng Wang, Yongxu Lu, Zhaowei Zhang and Xingang Zhao

Biomimetics 2025, 10(3), 129; https://doi.org/10.3390/biomimetics10030129 - 21 Feb 2025

Viewed by 645

Abstract

Stroke-related hand dysfunction significantly limits the ability to perform daily activities. Pneumatic soft gloves can provide rehabilitation training and support for individuals with impaired hand function, enhancing their independence. This paper presents a novel pneumatic soft robotic system for hand rehabilitation featuring bidirectional [...] Read more.

Stroke-related hand dysfunction significantly limits the ability to perform daily activities. Pneumatic soft gloves can provide rehabilitation training and support for individuals with impaired hand function, enhancing their independence. This paper presents a novel pneumatic soft robotic system for hand rehabilitation featuring bidirectional bending actuators. The system comprises a pneumatic soft glove and a pneumatic control platform, enabling various rehabilitation gestures and assisting with finger grasping. The main bending module of the pneumatic soft actuator features a three-stage cavity structure, allowing for a wider range of finger rehabilitation training gestures and greater bending angles. The reverse-bending module uses a trapezoidal cavity design to enhance the reverse-bending capability, effectively facilitating finger extension motion. The pneumatic control platform is simple to set up, but effectively controls the actuators of the soft glove, which enables both main and reverse bending. This allows individuals with hand impairments to perform various gestures and grasp different objects. Experiments demonstrate that the pneumatic soft glove has a measurable load capacity. Additionally, the pneumatic soft glove system is capable of executing single-finger movements, a variety of rehabilitation gestures, and the ability to grasp different objects. This functionality is highly beneficial for the rehabilitation of individuals with hand impairments. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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21 pages, 12168 KiB

Open AccessArticle

An Octopus-Inspired Soft Pneumatic Robotic Arm

by Emmanouil Papadakis, Dimitris P. Tsakiris and Michael Sfakiotakis

Biomimetics 2024, 9(12), 773; https://doi.org/10.3390/biomimetics9120773 - 19 Dec 2024

Cited by 1 | Viewed by 1909

Abstract

This paper addresses the design, development, control, and experimental evaluation of a soft robot arm whose actuation is inspired by the muscular structure of the octopus arm, one of the most agile biological manipulators. The robot arm is made of soft silicone and [...] Read more.

This paper addresses the design, development, control, and experimental evaluation of a soft robot arm whose actuation is inspired by the muscular structure of the octopus arm, one of the most agile biological manipulators. The robot arm is made of soft silicone and thus possesses enhanced compliance, which is beneficial in a variety of applications where the arm may come into contact with delicate features of its environment. The arm is composed of three elongated segments arranged in series, each one of which contains several pneumatically actuated chambers embedded in its silicone body, which may induce various types of deformations of the segment. By combining the segment deformations, and by imitating the antagonistic muscle group functionality of the octopus, the robot arm can bend in various directions, increase or decrease its length, as well as twist around its central axis. This is one of the few octopus-inspired soft robotic arms where twisting is replicated in its motion characteristics, thus greatly expanding the arm’s potential applications. We present the design process and the development steps of the soft arm, where the molding of two-part silicone of low hardness in 3d-printed molds is employed. In addition, we present the control methodology and the experimental evaluation of both a standalone segment and the entire three-segment arm. This experimental evaluation involves model-free closed-loop control schemes, exploiting visual feedback from a pair of external cameras in order to reconstruct in real time the shape of the soft arm and the pose of its tip. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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16 pages, 4067 KiB

Open AccessArticle

Neural Network-Based Shape Analysis and Control of Continuum Objects

by Yuqiao Dai, Shilin Zhang, Wei Cheng and Peng Li

Biomimetics 2024, 9(12), 772; https://doi.org/10.3390/biomimetics9120772 - 18 Dec 2024

Cited by 1 | Viewed by 805

Abstract

Soft robots are gaining increasing attention in current robotics research due to their continuum structure. However, accurately recognizing and reproducing the shape of such continuum robots remains a challenge. In this paper, we propose a novel approach that combines contour extraction with camera [...] Read more.

Soft robots are gaining increasing attention in current robotics research due to their continuum structure. However, accurately recognizing and reproducing the shape of such continuum robots remains a challenge. In this paper, we propose a novel approach that combines contour extraction with camera reconstruction to obtain shape features. Neural networks are employed to model the relationship between motor inputs and the resulting shape output. A simulation environment is established to verify the shape estimation and shape control of the flexible continuum. The outcomes demonstrate that this approach effectively predicts and reproduces the shape of flexible continuum robots, providing a promising solution for continuum shape control. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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13 pages, 5413 KiB

Open AccessArticle

Magnetically Driven Quadruped Soft Robot with Multimodal Motion for Targeted Drug Delivery

by Huibin Liu, Xiangyu Teng, Zezheng Qiao, Wenguang Yang and Bentao Zou

Biomimetics 2024, 9(9), 559; https://doi.org/10.3390/biomimetics9090559 - 16 Sep 2024

Cited by 1 | Viewed by 1898

Abstract

Untethered magnetic soft robots show great potential for biomedical and small-scale micromanipulation applications due to their high flexibility and ability to cause minimal damage. However, most current research on these robots focuses on marine and reptilian biomimicry, which limits their ability to move [...] Read more.

Untethered magnetic soft robots show great potential for biomedical and small-scale micromanipulation applications due to their high flexibility and ability to cause minimal damage. However, most current research on these robots focuses on marine and reptilian biomimicry, which limits their ability to move in unstructured environments. In this work, we design a quadruped soft robot with a magnetic top cover and a specific magnetization angle, drawing inspiration from the common locomotion patterns of quadrupeds in nature and integrating our unique actuation principle. It can crawl and tumble and, by adjusting the magnetic field parameters, it adapts its locomotion to environmental conditions, enabling it to cross obstacles and perform remote transportation and release of cargo. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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19 pages, 6591 KiB

Open AccessArticle

Finite-Time Line-of-Sight Guidance-Based Path-Following Control for a Wire-Driven Robot Fish

by Yuyang Mo, Weiheng Su, Zicun Hong, Yunquan Li and Yong Zhong

Biomimetics 2024, 9(9), 556; https://doi.org/10.3390/biomimetics9090556 - 15 Sep 2024

Cited by 2 | Viewed by 1188

Abstract

This paper presents an adaptive line-of-sight (LOS) guidance method, incorporating a finite-time sideslip angle observer to achieve precise planar path tracking of a bionic robotic fish driven by LOS. First, an adaptive LOS guidance method based on real-time cross-track error is presented. To [...] Read more.

This paper presents an adaptive line-of-sight (LOS) guidance method, incorporating a finite-time sideslip angle observer to achieve precise planar path tracking of a bionic robotic fish driven by LOS. First, an adaptive LOS guidance method based on real-time cross-track error is presented. To mitigate the adverse effects of the sideslip angle on tracking performance, a finite-time observer (FTO) based on finite-time convergence theory is employed to observe the time-varying sideslip angle and correct the target yaw. Subsequently, classical proportional–integral–derivative (PID) controllers are utilized to achieve yaw tracking, followed by static and dynamic yaw angle experiments for evaluation. Finally, the yaw-tracking-based path-tracking control strategy is applied to the robotic fish, whose motion is generated by an improved central pattern generator (CPG) and equipped with a six-axis inertial measurement unit for real-time swimming direction. Quantitative comparisons in tank experiments validate the effectiveness of the proposed method. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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Review

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20 pages, 7686 KiB

Open AccessReview

Learning from Octopuses: Cutting-Edge Developments and Future Directions

by Jinjie Duan, Yuning Lei, Jie Fang, Qi Qi, Zhiming Zhan and Yuxiang Wu

Biomimetics 2025, 10(4), 224; https://doi.org/10.3390/biomimetics10040224 - 4 Apr 2025

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Abstract

This paper reviews the research progress of bionic soft robot technology learned from octopuses. The number of related research papers increased from 760 in 2021 to 1170 in 2024 (Google Scholar query), with a growth rate of 53.95% in the past five years. [...] Read more.

This paper reviews the research progress of bionic soft robot technology learned from octopuses. The number of related research papers increased from 760 in 2021 to 1170 in 2024 (Google Scholar query), with a growth rate of 53.95% in the past five years. These studies mainly explore how humans can learn from the physiological characteristics of octopuses for sensor design, actuator development, processor architecture optimization, and intelligent optimization algorithms. The tentacle structure and nervous system of octopus have high flexibility and distributed control capabilities, which is an important reference for the design of soft robots. In terms of sensor technology, flexible strain sensors and suction cup sensors inspired by octopuses achieve accurate environmental perception and interaction. Actuator design uses octopus muscle fibers and movement patterns to develop various driving methods, including pneumatic, hydraulic and electric systems, which greatly improves the robot’s motion performance. In addition, the distributed nervous system of octopuses inspires multi-processor architecture and intelligent optimization algorithms. This paper also introduces the concept of expected functional safety for the first time to explore the safe design of soft robots in failure or unknown situations. Currently, there are more and more bionic soft robot technologies that draw on octopuses, and their application areas are constantly expanding. In the future, with further research on the physiological characteristics of octopuses and the integration of artificial intelligence and materials science, octopus soft robots are expected to show greater potential in adapting to complex environments, human–computer interaction, and medical applications. Full article

(This article belongs to the Special Issue Bio-Inspired Soft Robotics: Design, Fabrication and Applications)

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