Servopneumatic actuator of a robot with compensation for the mutual influence of movements of the degrees of mobility

This paper presents the results of investigation of the working capacity of a servopneumatic actuator with a reference model in the control system. This control scheme is used to compensate for the mutual influence of movements of various degrees of mobility in industrial robots in the form of force and parametric perturbations. Mathematical modeling and a full-scale test of the servopneumatic actuator with a reference model in the control system are carried out. The mathematical model contains thermodynamical pressure and temperature differential equations of compressed air state in pneumatic cylinder chambers; logical relationships determining the conditions for connection of the chambers with a feed line or atmosphere; equations describing the dynamics of the servovalve; equations of mechanical force balance on the cylinder shaft and relationships describing the control system. The results obtained show a satisfactory agreement between the calculated and experimental data and the possibility of partial compensation for the influence of the force perturbations on the motion of the servopneumatic actuator. Based on the linearized mathematical model, the smoothing coefficient was calculated with respect to external force disturbances. The control system with a reference model in the control loop makes it possible to increase the noise immunity by 23 % in comparison with the conventional control system.