For safe and compliant interaction: an outlook of soft underwater manipulators

Wang, Zhenhua; Cui, Weicheng

doi:10.1177/1475090220950911

Cited by 8 publications

(10 citation statements)

References 67 publications

(97 reference statements)

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“…The standard approach to describe the strain energy of the hyperelastic material is by applying a polynomial energy model [42]. For this study, the simplified polynomial Yeoh hyperelastic model as in (22) has been chosen to describe the energy potential.…”

Section: Dynamic Formulationmentioning

confidence: 99%

“…The stress σ h and σ v can be calculated, respectively according to (22) and (26), then the axial strain energy can be calculated by substituting (21) for (19). Finally, substituting the energy Equations ( 16), (18), and ( 19) for ( 15) and ( 14) to further deduce the local dynamics of the soft joint.…”

Section: Dynamic Formulationmentioning

confidence: 99%

“…Underwater soft robot technology has developed rapidly in recent years, such as octopus tentacle soft arm [19,20], elephant trunk arm [21,22], and deep-sea self-powered soft fish [23], which shows that soft robot has broad prospects in a marine application. This paper, inspired by the locomotion gait of biological snakes, proposes an innovative modular underwater snake robot actuated by rigid propulsions and soft joints, which can improve the swimming efficiency and flexibility of the robot and reduce the probability of collision leading to damage.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic Modeling of Underwater Snake Robot by Hybrid Rigid-Soft Actuation

Zhang

Chen

Liu

et al. 2022

JMSE

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For decades, underwater vehicles have been performing underwater operations, which are critical to the development and upgrading of underwater robots. With the advancement of technology, various types of robots have been developed. The underwater robotic snake is a bioinspired addition to the family of underwater robotic vehicles. In this paper, we propose an innovative underwater snake robot actuated by rigid propulsions and soft joints, which can improve the swimming efficiency and flexibility of the robot and reduce the probability of collision leading to damage. Existing math models of robotic snakes typically incorporate only planar motion, rarely considering spatial motion. So, we formulate a complete three-dimensional dynamic model for the robotic snake, which is extended by deriving expressions for the geometric Jacobians. This modeling approach is well suited since it provides compact matrix expressions and easy implementation. We use the constant curvature method to describe the configuration of the soft joint, use the Lagrangian method to obtain its dynamic characteristics, and focus on deriving the visco-hyperelastic mechanical energy of the soft material. Next, the local dynamics of soft members are extended as a nonholonomic constraint form for modeling the snake robot. Finally, the multi-modal swimming behavior of the robot has been verified by simulations, including forward and backward rectilinear motion, yaw turning, pitch motion, and spiral rising motion. The overall results demonstrate the effectiveness and the versatility of the developed dynamic model in the prediction of the robot trajectory, position, orientation, and velocity.

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Section: Dynamic Formulationmentioning

confidence: 99%

Section: Dynamic Formulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamic Modeling of Underwater Snake Robot by Hybrid Rigid-Soft Actuation

Zhang

Chen

Liu

et al. 2022

JMSE

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“…1,2 Furthermore, some hydraulic powered manipulators can work at deep sea depth of more than thousands of meters, which can overcome the high static pressure from hydrostatic in the water and would have larger load capacities. 3…”

Section: Introductionmentioning

confidence: 99%

A computation effective singularity avoidance method for the underwater manipulator with a non-spherical wrist

Gao

Wang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part M:

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In order to perform increasingly complex underwater tasks, we have designed a hydraulic underwater non-spherical wrist manipulator with a binocular vision system and a six-dimensional force sensor mounted behind the end-effector, which can improve the path accuracy and automation capabilities of the system. The system lays a foundation for the high precision and autonomous deep-sea operation and can improve its intelligence level. In this paper, we focus on solving the singularity avoidance problem of the hydraulic underwater manipulator for accurate control, and propose a computationally efficient singularity avoidance method to improve the path accuracy of the manipulator with the non-spherical wrist. Firstly, the singular configurations of the manipulator are analyzed. Secondly, the Jacobian is decomposed into sub-block matrices to obtain the singular factors according to the singular configurations. Thirdly, the singularities are avoided by the approximate damped reciprocal method. Theoretical analysis shows that the computation costs of the proposed method are only one-third to one-half of that of the traditional methods. The simulation results prove that the proposed method can largely improve the path accuracy of the manipulator with less computation costs, which shows that our method would have a certain significance in improving the precision and real-time response of deep-sea operations.

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“…A robotic manipulator is similar to the human arm and can replace or assist humans to complete the tasks of picking, placing, painting, welding, and assembling. The manipulator plays an important role in industrial production, underwater exploration, medical application, aerospace, and other fields [1][2][3][4]. To achieve a better control effect and meet the control requirements of different fields, the manipulator must have the ability to track a trajectory with high precision.…”

Section: Introductionmentioning

confidence: 99%

Adaptive Proportional Integral Robust Control of an Uncertain Robotic Manipulator Based on Deep Deterministic Policy Gradient

Huang

Xiao

et al. 2021

Mathematics

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An adaptive proportional integral robust (PIR) control method based on deep deterministic policy gradient (DDPGPIR) is proposed for n-link robotic manipulator systems with model uncertainty and time-varying external disturbances. In this paper, the uncertainty of the nonlinear dynamic model, time-varying external disturbance, and friction resistance of the n-link robotic manipulator are integrated into the uncertainty of the system, and the adaptive robust term is used to compensate for the uncertainty of the system. In addition, dynamic information of the n-link robotic manipulator is used as the input of the DDPG agent to search for the optimal parameters of the proportional integral robust controller in continuous action space. To ensure the DDPG agent’s stable and efficient learning, a reward function combining a Gaussian function and the Euclidean distance is designed. Finally, taking a two-link robot as an example, the simulation experiments of DDPGPIR and other control methods are compared. The results show that DDPGPIR has better adaptive ability, robustness, and higher trajectory tracking accuracy.

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For safe and compliant interaction: an outlook of soft underwater manipulators

Cited by 8 publications

References 67 publications

Dynamic Modeling of Underwater Snake Robot by Hybrid Rigid-Soft Actuation

Dynamic Modeling of Underwater Snake Robot by Hybrid Rigid-Soft Actuation

A computation effective singularity avoidance method for the underwater manipulator with a non-spherical wrist

Adaptive Proportional Integral Robust Control of an Uncertain Robotic Manipulator Based on Deep Deterministic Policy Gradient

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