The optimization of global fault tolerant trajectory for redundant manipulator based on self-motion

SUMMARYAn S-R-S (Spherical-Revolute-Spherical) redundant manipulator is similar to a human arm and is often used to perform dexterous tasks. To solve the inverse kinematics analytically, the arm-angle was usually used to parameterise the self-motion. However, the previous studies have had shortcomings; some methods cannot avoid algorithm singularity and some are unsuitable for configuration control because they use a temporary reference plane. In this paper, we propose a method of analytical inverse kinematics resolution based on dual arm-angle parameterisation. By making use of two orthogonal vectors to define two absolute reference planes, we obtain two arm angles that satisfy a specific condition. The algorithm singularity problem is avoided because there is always at least one arm angle to represent the redundancy. The dual arm angle method overcomes the shortcomings of traditional methods and retains the advantages of the arm angle. Another contribution of this paper is the derivation of the absolute reference attitude matrix, which is the key to the resolution of analytical inverse kinematics but has not been previously addressed. The simulation results for typical cases that include the algorithm singularity condition verified our method.

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Fault-tolerant motion planning and control of redundant manipulator

Control Engineering Practice ◽

10.1016/j.conengprac.2011.11.004 ◽

2012 ◽

Vol 20 (3) ◽

pp. 282-292 ◽

Cited By ~ 21

Author(s):

Kene Li ◽

Yunong Zhang

Keyword(s):

Motion Planning ◽

Fault Tolerant ◽

Redundant Manipulator ◽

Planning And Control ◽

And Control

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Redundant manipulator self-motion topology under joint limits with an 8-DOF case study

Proceedings of 1993 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS '93) ◽

10.1109/iros.1993.583191 ◽

2002 ◽

Cited By ~ 2

Author(s):

C.L. Luck ◽

S. Lee

Keyword(s):

Redundant Manipulator ◽

Joint Limits ◽

Self Motion

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Optimal Base Placement and Motion Planning for Mobile Manipulators

Volume 4: 36th Mechanisms and Robotics Conference, Parts A and B ◽

10.1115/detc2012-70600 ◽

2012 ◽

Author(s):

Bin Du ◽

Jing Zhao ◽

Chunyu Song

Keyword(s):

Motion Planning ◽

Great Influence ◽

Initial Point ◽

Mobile Manipulator ◽

Target Point ◽

Mobile Manipulators ◽

Redundant Manipulator ◽

Self Motion ◽

The Given ◽

Manipulation Capability

A mobile manipulator typically consists of a mobile platform and a robotic manipulator mounted on the platform. The base placement of the platform has a great influence on whether the manipulator can perform a given task. In view of the issue, a new approach to optimize the base placement for a specified task is proposed in this paper. Firstly, the workspace of a redundant manipulator is investigated. The manipulation capability of the redundant manipulator is maximized based on the manipulability index through the joint self-motion of the redundant manipulator. Then the maximum manipulation capability in the specified work point is determined. Next, the relative manipulability index (RMI) is defined for analyzing manipulation capability of the manipulator in its workspace, and the global manipulability map (GMM) is presented based on the above measure. Moreover, the optimal base placement related to the given task is obtained, and the motion planning is implemented by an improved rapidly-exploring random tree (RRT) algorithm with the RMI, which can enhance the manipulation capability from the initial point to the target point. Finally, the feasibility of the proposed algorithm is illustrated with numerical simulations and experiments on the mobile manipulator.

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