ENG644 Electronics

Task 1 - Modelling A d.c. motor is to be controlled using a variety of methods. Unfortunately, the control engineer does not have any suitable transfer function model of the system as a basis for controller design. In order to tackle this problem, a simple experimental feedback test rig is constructed, and various data are collected from the system. The data is noisy and uncertain, due to limitations of the methods used to collect it. Speed Response - Finding P (s) The first test is an open-loop test measuring motor speed (shown in Figure 1). An amplifier gain k = 2 is used, and the driving input is a step, by coincidence of 2 volts. Use the data of Figure 4 to deduce an appropriate transfer function model P (s). The model for P (s) does not need to be taken forward to any other tasks.       Figure 1: Experimental Rig - Adjusting Speed Position Response - Finding G1(s) The engineer adjusts the rig, so that the motor position is now controlled under feedback, with the motor represented by G1(s), and with a simple proportional gain (amplifier) in series with the motor, as shown in Figure 2. k is set to 20 for these experiments. Figure 2: Experimental Rig - Position Control Step response data is collected from the closed-loop rig and shown in Figure 5. The step input θi is 2V for this experiment. The experiment is not considered to provide any sort of a benchmark for the upcoming control problem