Adaptive PI control with feed-forward compensator for a weigh feeder

This paper proposes a new method for designing a weigh feeder controller. The dynamic characteristics of a weigh feeder are time-varying and its high frequency vibration modes are not easily identified. Hence, the precise model of a weigh feeder cannot be obtained. In the proposed method, the dynamic characteristics of the proposed control system are mainly decided by proportional and integral compensation, and transient response is improved using feedforward compensation. In design of the proposed method, the steady-state control input must be obtained because it is employed as feed-forward input. To this end, a weigh feeder is approximated as a first-order plus integrator system, and a self-tuning controller is designed on the basis of the approximated model to estimate its gain recursively. As a result, the proposed controller has a simple structure and its controller parameters can be understood intuitively. Consequently, the proposed design method can be easily adopted in industry. Numerical examples demonstrate its effectiveness.