A control method for the movement of a robot arm along a prescribed path

Abstract

A method for moving a robot arm along a prescribed path with sufficient accuracy and lower cost is presented. The entire path of movement is divided into n equal segments of fixed length 1 each. By using direction measurements or analytical methods, the location of each node on the path can be determined in the three-dimensional space. Then the straight distance d between each two consecutive nodes is determined. A series of fixed, symmetrical parabolic curves with length 1 but different curvature is defined and stored in the computer. On the basis of the value of d in relation to 1, a suitable curve is chosen and fitted between each two consecutive points. Since the execution strategy for each of these curves is already determined and stored in the computer, the overall execution time is reduced. This method seems to work well for smooth paths. The inverse kinematic problem can be solved to determine the position and velocity of each joint. The dynamic equations are then solved to determine the required torque for each joint.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>