COMPUTER SIMULATION OF THE ROADHEADER CUTTING HEAD SPEED CONTROL SYSTEM

ABSTRACT

The paper presents model-in-the loop simulation results of the roadheader cutting speed control system. The roadheader is equipped with an 132kW induction motor supplied from the frequency inverter. The output frequency is calculated by a PI speed controller on the basis of speed error (signal difference between a reference signal from the load controller and the measured signal from the incremental speed encoder). The whole control system model (involving an inverter model, sensor model, induction motor linearized model, cutting head model and a PI controller) has been implemented using a Matlab/Simulink package. The induction motor equivalent circuit parameters have been calculated using a manufacturers data. Special attention has been paid to frequency rate limiter at the input of the frequency inverter. The load torque has been implemented using real signals recorded at the laboratory stand. As a controller setting selection criteria there has been used an integral criterion (Integral of Time multiplied by Absolute value of Error). The system stability has been checked using a Nyquist criterion.

Keywords: roadheader, cutting head, PI controller, frequency inverter, induction motor, coal and rock cutting.