Obstacle Avoidance for Redundant Manipulators Utilizing a Backward Quadratic Search Algorithm. (8th June 2016)

• Record Type: Journal Article
• Authors: Hu, Tianjian; Wang, Tianshu; Li, Junfeng; Qian, Weiping
• Is Part Of: International journal of advanced robotic systems. Volume 13:Number 3(2016)
• Publication Date: 2016-06-08
• Subjects: Inverse Kinematics -- Redundant Manipulators -- Obstacle Avoidance -- Backward Quadratic Search Algorithm; Robotics -- Periodicals; Robotics; Periodicals; 629.892
• DOI: 10.5772/63934
• Languages: English
• ISSNs: 1729-8806

Abstract

Obstacle avoidance can be achieved as a secondary task by appropriate inverse kinematics (IK) resolution of redundant manipulators. Most prior literature requires the time-consuming determination of the closest point to the obstacle for every calculation step. Aiming at the relief of computational burden, this paper develops what is termed a backward quadratic search algorithm (BQSA) as another option for solving IK problems in obstacle avoidance. The BQSA detects possible collisions based on the root property of a category of quadratic functions, which are derived from ellipse-enveloped obstacles and the positions of each link's end-points. The algorithm executes a backward search for possible obstacle collisions, from the end-effector to the base, and avoids obstacles by utilizing a hybrid IK scheme, incorporating the damped least-squares method, the weighted least-norm method and the gradient projection method. Some details of the hybrid IK scheme, such as values of the damped factor, weights and the clamping velocity, are discussed, along with a comparison of computational load between previous methods and BQSA. Simulations of a planar seven-link manipulator and a PUMA 560 robot verify the effectiveness of BQSA.