Interactive mobile interface with augmented reality for learning digital control concepts

The use of augmented reality (AR) and mobile applications has recently been investigated in the teaching of advanced concepts and training of skills in a variety of fields. By developing educational mobile applications that incorporate augmented reality, unique interactive learning experiences can be provided to learners on their personal smartphones and tablet computers. This paper presents the development of an immersive user interface on a tablet device that can be used by engineering students to interact with a motor test-bed as they examine the effects of discrete-time pole locations on the closed-loop dynamic response of the test-bed. Specifically, users point the rear-facing camera of the tablet at the test-bed on which colored markers are affixed to enable an image processing routine running on the tablet to measure the angular position of an arm attached to the motor. To perform vision-based control of the angular position of motor arm, a discrete-time Kalman filter and a full-state feedback controller are implemented in the background of the application. As the user taps on the touchscreen of the device, s/he adjusts the angular position of a 3D semi-transparent virtual arm that represents the set point to the system. An interactive pole-zero plot allows users to tap at any desired location for the closed-loop pole-placement, in turn triggering the application code to redesign a new controller for driving the test-bed. Real-time plots enable the user to explore the resulting closed-loop response of the test-bed. Experimental results show several responses of the test-bed to demonstrate the efficacy of the proposed system.