Analysis And Design Of Force Servo System Based On Two Degree Of Freedom Control

Fire control systems are important part of the tanks, self-propelled guns and otherarmored, which can make artillery targeting rapidly and accurately. With widelyapplication of high-tech, current testing methods have been unable to meet therequirements of the perfomance test for fire control systems. Here we present a new testscheme. During the test, to meet the requirements for the force servo system with highservo precision and fast dynamic response, this paper aims to design controller for forceservo system driven by linear motor.According to the design index, the hardware architecture and components of thesystem are confirmed. Based on mechanism analysis, the model of force servo systemhas been derived. Considering the uncertainty disturbance within the system, the modelof friction and ripple force are established.Based on two degrees-of-freedom(DOF) control strategy, the controller with thedisturbance observer(DOB) has been designed for the inner loop. The basic idea andprinciple of DOB are introduced, and then the system performance is analysisedrelating to parameters of lowpass filter in DOB. Combining the model and low passfilter, the DOB is designed in speed loop. After analysing the infeasibility of controllerdesign for speed loop based on the force servo model, the rate controller is desginedbased on the position servo model. The characteristic of speed closed loop system istestified through simulation, the result shows well immunity to disturbance.Usually the artillery produces periodic vibrations when being forced to move. Therepetitive control is introduced as to rejecting the specific fluctuation. Prepared to originsystem, performance of system with plug-in control structure is studied in some aspectsas robust stability, trade-off accuracy and transient characteristics. Based on thediscussion and analysis, the design method and process is proposed. In application ofthe two degrees-of-freedom(DOF) control strategy, controller for outer loop is designedcombined with the plug-in control structure. The result of simulation indicates thattracking accuracy and disturbance rejection of the force servo system has been greatlyimproved.