Vladareanu L.

A new control method of the compliant robots control systems with function insertion is presented. It consists of a fuzzy multi-stage (MS) control on two different decision stages in order to determine the gripper’s movement velocity that implies the realization of two fuzzy control loops one in position and the other in force. The architecture of the compliant robots control systems with function insertion allows for practically eliminating jamming and vibrations, having a fast response of the control loop. The controller´s basic concept is to ensure velocity on each axis, for the given deflection in the corresponding direction, like a human operator that would perform the insertion. The controller’s role is to ensure the measured deflection of the fuzzy variables and to evaluate the decision rules through inference, so that, in the end, it is able to establish the value of the output variable, for instance the velocity as a fuzzy variable, which best follows the controlled parameter. The relation between the inputs, such as the measured deviations, or outputs, such as the velocities, and the degree of membership can be defined according to the operator’s experiences and the robot task’s requirements. The result of the logical inference also represents fuzzy values that apply to the defuzzify mode. The defuzzyfied outputs are generated by choosing as a defuzzyification method the weight centre of the aria method. Generating a discreet discourse universe makes it possible to use a PLC system for generating the fuzzy output variables within a short processing time. By applying the fuzzy logical control a smooth passing, without any discontinuities, is obtained from the control in position to the control in force and position. Moreover, a fast reply from the control loop is obtained and jamming respectively vibrations are practically eliminated.