New Orleans, Louisiana
June 26, 2016
June 26, 2016
August 28, 2016
Ocean and Marine
Many marine engineering programs feature the opportunity for students to take a controls theory class as part of their curriculum, either as a required course or as an elective. While the benefit of providing a hands-on demonstration for theoretical material is well-known, controls courses often suffer from the lack of affordable, robust hands-on hardware for student use. Instructors in such courses can struggle to find the appropriate balance between the opportunity to maximize hands-on learning and the costs and risks to delicate and expensive equipment that such opportunities afford.
The authors propose an affordable ball-and-beam controls system as a student-built project. The students were presented with the challenge of rolling a ball along a centrally pivoted rail (akin to a see-saw) and controlling the angle of the beam in such manner so as to make the ball roll and then stop and hold position within 5 centimeters of the end without falling off. Successful completion of the challenge was assigned a score worth 20% of the grade in the course.
Students enrolled in the course developed the transfer function for the ball-and-beam system by approximating the ball as a homogeneous sphere of known diameter that rolls without slipping. Small-angle approximations were used for the external input. The control system consisted of an electrical servo motor controlled by a commercially available open-course microcontroller. Students developed their own text-based code or “sketch” to program the microcontroller with a “PD” (proportional-plus-derivative) control algorithm.
The project was successfully piloted in a senior level controls course at the authors’ institution. Benefits to the project include the hands-on application of theoretical material, portability and low cost. The latter was particularly helpful as it provided the students with a level of ownership and control over the project. The total cost of the project is less than the retail cost of a typical new-edition textbook. An end of semester assessment via direct observation techniques showed that 100% of the students attempting the controller design challenge were able to successfully design a working controller. The project is proposed for consideration by programs seeking to liven up an otherwise heavily theoretical course with a hands-on, yet affordable, activity.
Clippinger, D., & Adrezin, R., & Regan, M. S. (2016, June), Design of an Economical Student-built Automatic Control System Paper presented at 2016 ASEE Annual Conference & Exposition, New Orleans, Louisiana. 10.18260/p.26682
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