Fault Detection and Isolation Method for Injection Unit with Reaction Force Sensor

In this paper, we propose a method of detecting and isolating the faults of the reaction force sensor and the actuator of an injection unit. The injection unit is controlled by a speed control feedback with a reaction force sensor. We construct a residual generator by using an observer of the reaction force, and we give a fault detection system that utilizes the residual signals. The properties of the transfer functions from the sensor output and the control input to the residual signals are analyzed, and the frequency characteristics of the speed control system and that of the reaction force are utilized. Our method can be executed on the normal operation mode. Usefulness of our method is demonstrated by simulation for the actual values of the system parameters.