The effects of computational delays on the model-based control of manipulators

Abstract

The effects of varying computational delays and sample frequencies on the dynamic performance of a 2-degree-of-freedom (DOF) manipulator and a 6-DOF PUMA 560 manipulator, both operating under model-based/proportional-derivative (PD) control, are investigated. A simplified analysis is used to demonstrate the destabilizing effects of delays in linear analog control systems. The imperfect cancellations caused by delays in a model-based control law are analyzed for the general case. Simulations of a two-link planar robot and the PUMA 560 manipulator demonstrate unstable behavior with various input trajectories. In all cases, instabilities occur over a wider range of delay times as the sample period increases.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>