Albuquerque, New Mexico
June 24, 2001
June 24, 2001
June 27, 2001
6.30.1 - 6.30.33
A feedback control system for incorporation into an Engineering Technology controls laboratory has been developed. The purpose of developing a working control system is to reinforce controls theory taught in the classroom. A control system for positioning an air cylinder driven load platform was selected for the design. By controlling the height of the column of air in the air cylinder and regulating the pressure applied to the air cylinder piston, the platform could be positioned anywhere within the range of the air cylinder travel. To demonstrate the control capability of the system, random load disturbances were generated by adding and removing laboratory weights to the platform, with the desired setpoint position maintained. The instructional benefit of selecting a position control system was that the reaction of the control system could be readily observed as the platform returned to the set point position. The PID controller gain constants were found first by using the Ziegler-Nichols Method of controller design. In this method, the system gain is increased to the point of oscillation. The gain for oscillation and frequency of oscillation will be inserted into a table of tuning rules to determine the value of PID controller constants. Next, the dynamics of individual components of the system were characterized through experimentation and modeling. A Laplace transform transfer function representation of the system was found and then analyzed using simulation software and root-locus analysis. The gain for oscillation and frequency of oscillation were determined from the root-locus plot. The Ziegler-Nichols Tuning rules where then re-applied to find the value of the PID controller constants. A comparison of system performance using experimentally determined PID constants and theoretically determined PID constants was presented. Ideally, the constants and resulting system response using both methods would be equal. The time domain closed loop response of the theoretical model was found by computer simulation and then compared to data taken from the actual system.
Somerville Jr., J., & Macia, N. (2001, June), A Feedback Control System For Engineering Technology Laboratory Courses Paper presented at 2001 Annual Conference, Albuquerque, New Mexico. https://peer.asee.org/9271
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