The Cartesian Path Planning of Free-Floating Space Robot using Particle Swarm Optimization

Cheng Li,Yangsheng Xu,Bin Liang,Yu Liu,Wenfu Xu

doi:10.5772/5605

Abstract

The Cartesian path planning of free-floating space robot is much more complex than that of fixed-based manipulators, since the end-effector pose (position and orientation) is path dependent, and the position-level kinematic equations can not be used to determine the joint angles. In this paper, a method based on particle swarm optimization (PSO) is proposed to solve this problem. Firstly, we parameterize the joint trajectory using polynomial functions, and then normalize the parameterized trajectory. Secondly, the Cartesian path planning is transformed to an optimization problem by integrating the differential kinematic equations. The object function is defined according to the accuracy requirement, and it is the function of the parameters to be defined. Finally, we use the Particle Swarm Optimization (PSO) algorithm to search the unknown parameters. The approach has the following traits: 1) The limits on joint angles, rates and accelerations are included in the planning algorithm; 2) There exist not any kinematic and dynamic singularities, since only the direct kinematic equations are used; 3) The attitude singularities do not exist, for the orientation is represented by quaternion; 4) The optimization algorithm is not affected by the initial parameters. Simulation results verify the proposed method.

Highlights

Robotic systems are expected to play an increasingly important role in the future space activity
The position-level kinematic equation can not be used to plan the Cartesian path, it is often used by the fixedbased manipulators
After parameterization and normalization of joint trajectories, the planning problem is transformed to an optimization problem, and the Particle Swarm Optimization (PSO) algorithm is used to search the parameters to be determined

Summary

Introduction

Robotic systems are expected to play an increasingly important role in the future space activity. Huang et al presented a minimumtorque path-planning scheme in joint space (Huang et al, 2006) For inertial manipulation, such as capturing a free object, some methods based on Generalized Jacobian Matrix (GJM) are proposed (Umetani & Yoshida, 1989; Moosavian & Papadopoulos, 1997; Moosavian & Papadopoulos, 2007; Traira et al, 2000). Based on the calculation of PIW (Path Independent Workspaces) and PDW (Path Dependent Workspace), Papadopoulos (Papadopoulos, 1992) proposed a planning algorithm that avoids dynamic singularities, and permits the manipulator’s end-effector to move from any reachable workspace location to any other. In Section four, the joint functions are parameterized and normalized, and the PSO algorithm is used to solve the path planning problem.

Modeling of Space Robotic System

Problem of the Cartesian Path Planning

Solution to the Path planning Problem Based on Particle Swarm Optimization

Simulation Study

Conclusion and Discussion

Reference