June 23, 2013
June 23, 2013
June 26, 2013
23.1290.1 - 23.1290.17
Use of an Analogy to Demonstrate the Origin and Nature of Steady-State Errors in Control Systems AbstractAn introductory control systems course can be challenging to undergraduate students dueto its fairly sophisticated mathematical nature. For example, it can be difficult tocomprehend how even a system composed of perfect components could have a steady-stateerror. To help students understand such non-intuitive concepts, it is beneficial to offerthem a visual example that involves a familiar scenario. This paper describes a car raceanalogy which leverages these two complementary techniques in a semester course forjuniors and seniors in automatic control systems.The analogy consists of two competing cars of differing masses and air drags with variousinputs via the gas pedal. Equations of motion are presented for the displacement, velocity,and acceleration for step, ramp, and parabolic inputs. MATLAB® software is used tosolve the equations and plot the results for analysis and comparison. This familiarillustrative scenario allows students to discover easily and quickly how steady-statedifferences (analogous to errors) depend on the nature of the system and its type of input.It also demonstrates the effects of some easily understood corrective actions to reduce oreliminate the differences and reinforces understanding of the derivative-integralrelationships between the displacement, velocity, and acceleration responses.The graphical nature of this illustration fits well with the visual learning style of manystudents. Through this multi-faceted investigative analogy, they gain an intuitiveunderstanding of steady-state errors as a complement to the traditional mathematicaltreatment. Results of a voluntary survey completed by 19 (56%) of the 34 combinedenrollees during the fall semesters of 2010 and 2011 indicated that they found the car raceanalogy helpful in understanding the origin and nature of steady-state errors in controlsystems.Robert J. Albright received the B.S. and M.S. degrees in electrical engineering from OregonState University, Corvallis, in 1963 and 1965, respectively, and the Ph.D. degree in electricalengineering from the University of Washington, Seattle, in 1971.He is a Professor and Chair of Electrical Engineering at the University of Portland, Portland, OR.A member of the faculty of the University of Portland since 1970, he has served 33 years asChair of Electrical Engineering, 12 years as Chair of Computer Science, and one year as ActingDean of Engineering. He has been honored as a Tyson Distinguished Professor at the Universityof Portland. His teaching, research, and consulting interests include energy conversion, powersystems, control systems, and engineering education.Dr. Albright, a registered engineer in the State of Oregon, is a senior member of the IEEE and amember of the ASEE.
Albright, R. J. (2013, June), Use of an Analogy to Demonstrate the Origin and Nature of Steady-State Errors in Control Systems Paper presented at 2013 ASEE Annual Conference & Exposition, Atlanta, Georgia. https://peer.asee.org/22675
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