June 14, 2009
June 14, 2009
June 17, 2009
Electrical and Computer
14.809.1 - 14.809.13
Introducing Sophomore Engineering Students to Control Theory Using Mobile Robots
Control theory is an important element of engineering education in many disciplines. However, most programs do not introduce this topic until the junior year at the earliest. In this paper, we present an approach for the early introduction of PID control theory in a sophomore-level Introduction to Digital Systems course.
Control theory is introduced as a method to guide the motion of a custom mobile robot. The mobile robot utilizes a commercial chassis, wheels and tracks along with geared DC motors that include embedded quadrature position encoders. In addition to the chassis, we have developed custom hardware for the robot control and peripheral interface, including an interface to an Atmel ATmega324P microprocessor-based daughterboard for student- developed code. Peripherals include an accelerometer, IR range finder attached to a 180° rotating servo, IR and light sensors, push buttons, three potentiometers and display devices including a set of seven-segment LEDs.
To introduce control theory, students are required to develop a strategy for autonomously navigating a maze. To do so, it is first necessary to control the robot’s motors such that the robot will predictably travel in a straight path. Using the position encoders, wheel speed and direction are estimated. This data is compared between the two motors from which an error signal, proportional to speed or position error, is fed to a PID controller. The gains for the PID controller are tuned by the students as settings on the potentiometers. Once the desired motion characteristics are controllable, the students then attempt to use the IR range finder and rotating servo along with pre-defined maze information to navigate the robot from the starting point to the finish line.
In this paper, we discuss the features of our robot that allow us to introduce control system theory. We then discuss how the material was integrated into a sophomore-level digital systems course. Next, we discuss the implementation of PID control for the robots. Finally, we conclude with lessons learned and ideas for an improved learning experience.
In our sophomore-level Introduction to Digital Systems course, topics progress from basic digital logic design to introductory microcontroller architecture. In the last portion of the course (weeks 9-14), students learn about embedded programming in C using the Altera ATmega324P microcontroller1 for the purposes of controlling a mobile robot. These labs begin with basic motion and peripheral control and eventually lead to the implementation of a PID control system for predictable motion. The final design
Dunne, B., & Parikh, C., & Sterian, A. (2009, June), Introducing Sophomore Engineering Students To Control Theory Using Mobile Robots Paper presented at 2009 Annual Conference & Exposition, Austin, Texas. https://peer.asee.org/5117
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