A Music-Based Mechatronic System for Teaching Modeling and Control

Audio-based tools can enhance the learning experience in introductory modeling and control classes at the undergraduate (sophomore) level in the mechanical engineering curriculum. An example audio-based learning tool that we propose is the “FlexSynth,” a servo-actuated flexural rocker arm that sways to an electronically generated music. We have built and tested the FlexSynth as part of a project under the MIT advanced graduate subject 2.737 Mechatronics class offered in Fall 2007. The angular range of the rocking motion of the flexural arm in the FlexSynth is mapped to a set of musical notes. While the flexural rocker swayed to the generated ‘command’ music, its motion is also converted into an equivalent ‘response’ music. Two speakers are used, one to play the commanded music and the other to play the response music. The performance of control algorithms (such as proportional or proportional-integral control) can be discerned from the command and response music, and compared for better musical quality. The appeal of an electromechanical system, driven by music and controlled to see the ‘dancing’ flexural rocker, makes the overall system an interesting show-and-tell for young kids or the public at large, getting them excited about science and engineering automation. Advanced control issues such as filtering of flexural damping modes of the rocker can also be addressed with this system implementation. Advanced students in the controls area can study the design tradeoffs between robustness and speed in following the command music. While the usual debugging tools such as multimeters, oscilloscopes, and dynamic signal analyzers allow for hands-on learning about the performance of a control system, an audio-based unit such as the FlexSynth can be a valuable addition to the innovative teaching tool kit.