Fuzzy controller as means of increase of positioning accuracy and performance in the control system for small linear displacements

The article considers the problem of synthesis of a fuzzy controller to regulate the position of the solenoid exhalation valve of lungmotor. It is proposed to use asymmetric rule base, conventionally consisting of two subsystems that differ according to the principle of forming the control action due to the nature of the resistance force. Thus, in the direction of resistance to motion the principle of start-stop control is applied as optimal with respect to positioning speed. The attribute of the opposite direction is relatively smooth change of control in order to eliminate overshoot significant in magnitude. For the membership function of the regulator input variable ∆x (position error) it is recommended to use asymmetrical arrangement of the terms relative to the center symbolizing the change of direction. This allows avoiding of the state of stable oscillation of the valve working body position. The simulation results for the developed control system based on fuzzy logic show the high quality of transients both in speed and in accuracy of positioning which allows recommendation of the principles of fuzzy controller synthesis that are similar to considered electromagnetic exhalation valve in working principle.