Establishing a cost effective embedded control and robotics engineering program: Linear optimal control design using LEGOs

The cost of establishing a traditional control systems and robotics program usually runs into many thousands of dollars. As a result many undergraduate and graduate STEM institutions are unable to establish these important STEM programs in their curriculum. This paper introduces an alternative method of teaching important control system and robotics concepts using LEGO kits and ROBOTC software. Such a program has been successfully implemented in NYIT´s school of electrical and computer engineering. In this paper, the design and optimal control of the LEGO Mindstorms NXT motor system is studied. The system for which we design this controller is pre-identified and control is implemented with a state feedback controller. The system´s open and closed loop dynamics are computed and the responses are observed. We first check the observability and controllability criteria for the system. We then design an LQR based state feedback controller and using a Kalman filter observer. The controller is then implemented as an H₂ (LQG) optimal controller. The performance of H₂ controller is analyzed and simulated. The controllers are then implemented and validated on the prototype.