A LEGO based undergraduate control systems laboratory

The cost of establishing a traditional control systems laboratory usually runs into many thousands of dollars. This paper introduces an alternative method of teaching a control systems laboratory for undergraduate engineering students using LEGO NXT kits and ROBOTC software. The total cost of the kit and the software is under $350 which makes this combination a very cheap alternative for establishing a control systems laboratory. The set of experiments described here are ideal for colleges and universities that wish to introduce a control system laboratory curriculum at a minimal cost. In the first experiment the students observe and explore the working of the inbuilt ROBOTC PID controller for the LEGO NXT motor. In the second experiment, tuning of the PID controller assuming the system equations of the LEGO NXT motor system are unknown is studied. Ziegler-Nichols (Z-N) method and its Tyreus-Luyben (T-L) modification are also studied. In the third experiment, the transfer function of the LEGO NXT motor is derived using system identification by the experimental data modeling approach. PID control design using the new model is then finally studied in the fourth experiment using the experimentally obtained transfer function.