Development of a non-linear force controller using fuzzy logic techniques

摘要

As the demand for robots to perform complex tasks grows, there is an increasing need to utilize robust and stable force control strategies. Most current schemes can only provide adequate force control with the controller tuned to specific task requirements since, if there is a wide variation in the overall compliance at the robot tool/task interface, the performance is rapidly degraded. This paper describes a method for the design of a fuzzy logic controller to replace a conventional controller in a force control loop. The method combines an analytical approach to controller tuning, with the intuitive properties and self-adjusting gain characteristics associated with fuzzy logic systems. It is demonstrated using a model of a single-axis experimental rig and is shown to perform well over a wide range of stiffnesses. The implementation of the controller on the actual rig is also described. Experimental results compare favourably with those obtained from simulation using an accurate model of the system. Issues relating to the implementation of the controller on multi-axis systems are also addressed.