Current control in the drives of dexterous robot grippers

Abstract

At present, the actuality of improving approaches to the creation of dexterous gripper for robots with force controls and their control algorithms is growing due to the need to develop areas of robotics related to the manipulation of fragile objects, interaction with people, prosthetics and rehabilitation robotics. The force control in the dexterous grippers of robots using an electric drive is provided by current control. Therefore, the purpose of this article is to consider various current regulators in the context of their application in dexterous grippers and manipulators with the force control. PI, adaptive, relay and relay, with adjustment of the hysteresis loop, current regulators are compared in such characteristics as transient response, accuracy, robustness, switching losses and switching frequency stability. The article proposes a new method for synthesizing hysteresis regulators with the adjustment of the hysteresis loop, which assumes the use of standard frequency synthesis of control systems with feedback. The proposed method extends such quality parameters as stability stocks, transient time, cutoff frequency to the adjustment loop. The considered hysteresis controller with the adjustment loop, in contrast to the classical hysteresis regulator, ensures the stabilization of the switching frequency and the reduction of the current pulsations in the motor driver. The article also presents the results of the two-finger gripper force control with the use of various current regulators for the chosen law of forces distribution between the drives.