Novel Method of Obstacle Avoidance Planning for Redundant Sliding Manipulators

Liu, Jinguo; Tong, Yuchuang; Ju, Zhaojie; Liu, Yuwang

doi:10.1109/access.2020.2990555

Cited by 18 publications

(9 citation statements)

References 35 publications

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“…Current mainstream methods for solving the obstacle avoidance problem for a redundant manipulator mainly consist of numerical methods based on the Jacobian matrix [7] that are mainly used for real-time obstacle avoidance. The traditional trajectory obstacle avoidance algorithm uses the gradient projection method (GPM) [8][9][10] to divide the motion of a redundant manipulator into the main task and the secondary task. The former reflects the movement of the end effector, and the latter can use the redundant characteristics of manipulator to avoid obstacles or perform other secondary tasks by setting a optimisation function.…”

Section: Related Workmentioning

confidence: 99%

Obstacle avoidance method for fixed trajectory of a seven-degree-of-freedom manipulator

Quan

Wang²,

Zhao³

et al. 2023

Robotica

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This paper, based on the idea of redundancy angle discretisation, proposes an obstacle avoidance method for the fixed tip pose trajectory of a seven degrees-of-freedom (7-DOF) modular manipulator. First, for the case in which a specific redundancy angle is given, the analytical solutions of the redundant manipulator left 6-DOF subchain are found. Then, through the discretisation of the redundancy angle, the concept of the self-motion space of the tip pose is proposed and is extended to the concept of the self-motion space of the trajectory. Based on this discrete space, a path-planning algorithm is proposed to help select the appropriate redundancy angles to obtain the collision-free solution set of the fixed Cartesian trajectory. However, due to the large fluctuation of the obtained path, a path optimisation method based on the path cost is proposed to smooth the path, and the continuous and collision-free solution set of the manipulator tip’s trajectory is obtained. The method proposed in this paper provides a new thought for the problem of collision-free solution set planning for the Cartesian trajectory of a 7-DOF manipulator and it has great application potential in working environments with high accuracy requirements for the trajectory.

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Section: Related Workmentioning

confidence: 99%

Obstacle avoidance method for fixed trajectory of a seven-degree-of-freedom manipulator

Quan

Wang²,

Zhao³

et al. 2023

Robotica

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show abstract

“…The angular displacements ∆θ i (i ∈ [1,2,3,4,5,6,7]) are used to describe the deviation between the deformed position and the ideal position of the links. Moreover, the angular displacements are used to qualitatively describe the dynamic precision caused by the elastic deformation of the manipulator.…”

Section: Natural Frequency and Main Vibration Of The Systemmentioning

confidence: 99%

“…With the progress of exploration and the change of experiment demand, more and more scientific experiments require the redundant manipulators to simultaneously possess the ability to carry out autonomous and precise operations to improve the efficiency and operational safety [4,5]. Therefore, research on the dynamic accuracy of redundant manipulators has become an important part of robotic technology [6,7].…”

Section: Introductionmentioning

confidence: 99%

Dynamic Precision Analysis of a Redundant Sliding Manipulator

Tong

Liu

et al. 2020

Communications in Computer and Information Science

Self Cite

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This paper deals with the dynamic precision analysis of a linear-type rail redundant sliding manipulator. Based on the analysis of the mechanism structure, kinematics, stiffness performance and dynamic characteristics of the redundant sliding manipulator, the dynamic error caused by elastic deformation of links is analyzed. A mathematical model of the dynamic precision of the redundant sliding manipulator system is established in this paper by the geometric method. The influence of parameters such as equivalent stiffness and moment of inertia on the dynamic error of the manipulator is analyzed and parameter optimization schemes are proposed to reduce the dynamic error. Simulation analysis and experiment verify the dynamic precision of the redundant sliding manipulator. This paper provides a theoretical guidance for the highprecision operations of the redundant sliding manipulator.

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“…Combined with DSL and WLN, Zhang [ 12 ] presented an improved weighted gradient projection method (IWGPM), in which the manipulator can handle joint singularity and joint position limits, but it increases the tracking error. To coordinate end-effector motion and self-motion, Liu [ 13 ] proposed a weighted additional deviation velocity based on the gradient project method (GP-WADV). However, coping with multiple constraints simultaneously is still hard for these methods.…”

Section: Introductionmentioning

confidence: 99%

Reinforcement Learning-Based Reactive Obstacle Avoidance Method for Redundant Manipulators

Shen

Jia

Huang

et al. 2022

Entropy

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Redundant manipulators are widely used in fields such as human-robot collaboration due to their good flexibility. To ensure efficiency and safety, the manipulator is required to avoid obstacles while tracking a desired trajectory in many tasks. Conventional methods for obstacle avoidance of redundant manipulators may encounter joint singularity or exceed joint position limits while tracking the desired trajectory. By integrating deep reinforcement learning into the gradient projection method, a reactive obstacle avoidance method for redundant manipulators is proposed. We establish a general DRL framework for obstacle avoidance, and then a reinforcement learning agent is applied to learn motion in the null space of the redundant manipulator Jacobian matrix. The reward function of reinforcement learning is redesigned to handle multiple constraints automatically. Specifically, the manipulability index is introduced into the reward function, and thus the manipulator can maintain high manipulability to avoid joint singularity while executing tasks. To show the effectiveness of the proposed method, the simulation of 4 degrees of planar manipulator freedom is given. Compared with the gradient projection method, the proposed method outperforms in a success rate of obstacles avoidance, average manipulability, and time efficiency.

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Novel Method of Obstacle Avoidance Planning for Redundant Sliding Manipulators

Cited by 18 publications

References 35 publications

Obstacle avoidance method for fixed trajectory of a seven-degree-of-freedom manipulator

Obstacle avoidance method for fixed trajectory of a seven-degree-of-freedom manipulator

Dynamic Precision Analysis of a Redundant Sliding Manipulator

Reinforcement Learning-Based Reactive Obstacle Avoidance Method for Redundant Manipulators

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