Collision-avoidance control for redundant articulated robots

Abstract

SummaryA new mathematical formulation of robot and obstacles is presented such that for on-line collision recognition only robot joint positions in the workspace are required. This reduces calculation time essentially because joint positions in workspace can be computed every time from the joint variables through robot geometry. It is assumed that the obstacles in the workspace of the manipulator are represented by convex polygons. For every link of the redundant robot and every obstacle a boundary ellipse is defined in workspace such that there is no collision if the robot joints are outside this ellipsis.In addition to this, a collision avoidance method is presented which allows the use of redundant degrees of freedom such that a manipulator can avoid obstacles while tracking the desired end-effector trajectory. The method is based on the generalized inverse with boundary ellipse functions as optimization criteria. The method permits the tip of the hand to approach any arbitrary point in the free space while the kinematic control algorithm maximizes the boundary ellipse function of the critical link. The effectiveness of the proposed methods is discussed by theoretical considerations and illustrated by simulations of the motion of three- and four-link planar manipulators between obstacles.

Obstacle Avoidance for Spatial Hyper‐Redundant Manipulators Using Harmonic Potential Functions and the Mode Shape Technique

“…Some of the earlier approaches to obstacle avoidance of redundant manipulators in two dimensions (2D) are based on the Jacobian and make use of inverse kinematics at the velocity level. [1][2][3][4] In their ap-proach, the null space of the Jacobian matrix is utilized, which configures the links without affecting the end-effector motion. The null space component includes an arbitrary vector that can be used as a performance criterion such as obstacle avoidance.…”

A Hybrid Obstacle-Avoidance Method of Spatial Hyper-Redundant Manipulators for Servicing in Confined Space

“…This simplified approach satisfied the demand for obstacle-avoidance planning in time-varying environments. Later, Rahmanian-Shahri et al 6 proposed another online collision detection method using ellipses to model links and obstacles in the plane. Perdereau et al 7 offered a feasible solution for the real-time operation of a redundant robot moving in a variable environment.…”

Dynamic self-collision detection and prevention for 2-DOF robot arms using interval-based analysis

“…The first category is based on kinematic analysis, which assumes that the reference trajectory is specified in terms of path endpoints and a set of knots between the endpoints. The trajectory through the knots is generated to prevent self-collision by considering the geometric relationships and ranges of joint motion [1][2][3][4][5][6][7]. However, the kinematic-based approaches ignore dynamic constraints, such as inertia and force/torque capacity.…”