Received November 30, 2021, accepted December 16, 2021, date of publication January 7, 2022, date of current version January 13, 2022. Digital Object Identifier 10.1109/ACCESS.2022.3141588 A Project-Based Learning Approach for Building an Affordable Control Teaching Lab: The Centrifugal Ring Positioner XAVIER JORDENS , ROBIN WILMART , EMANUELE GARONE , (Member, IEEE), MICHEL KINNAERT , (Member, IEEE), AND LAURENT CATOIRE Department of Control Engineering and System Analysis, Université Libre de Bruxelles, 1050 Bruxelles, Belgium Corresponding author: Xavier Jordens (xavier.jordens@ulb.be) ABSTRACT This paper presents a novel experimental setup for teaching control engineering. This setup was developed during a project-based learning activity. The approach consists in training a master student in mechatronics and control through the design, manufacturing, and control of a device that will contribute over time to the education of students by laboratory sessions based on the device. The latter is an easy-to- build, reproducible, and affordable experimental setup called the Centrifugal Ring Positioner (CRP). It aims at illustrating several concepts of closed-loop control (e.g. system identification, model validation, and controller design and validation) while getting acquainted with typical experimental issues like the handling of measurement noise and the real-time implementation of a control law. The CRP distinguishes itself from most pedagogical benchmarks by the wide use of 3D printing. It is an unstable and nonlinear system, consisting of a ring able to slide on a rod thanks to the balance between gravity and centrifugal force. The control of the system aims at stabilizing the ring at any fixed position on the rod. The complete methodology followed during the project-based learning approach to build and control a CRP is detailed, including derivation of a dynamic model based on classical mechanics theory, considerations on the mechanical design, selection of the components, step response and physics-based model identification, and PID controllers design based on computer-assisted methods such as root locus and Bode diagrams. INDEX TERMS 3D printing, centrifugal ring positioner, control engineering education, control systems, mechatronics, teaching lab. I. INTRODUCTION Control systems are present in many fields in today’s world, ranging from manufacturing processes to consumer products. Implementation of new technological systems is partially possible thanks to the evolution of control theory; this evolu- tion being closely linked to teaching activities and constantly evolving research. Control engineering students should be able to make connections between theoretical and practical control systems concepts (data acquisition system, real-time software, sensors. . . ) through practical experiments [1], [2]. They must have the opportunity to confront the theory to practical cases to become aware of potential imperfections arising from real systems complexity such as disturbances, measurement noises, and model uncertainties [3]. Hands-on The associate editor coordinating the review of this manuscript and approving it for publication was Bidyadhar Subudhi . experimentations should allow to verify classical techniques, perform model validation experiments, and develop new tools and verify their implementation [1], [4]. This reflection is what is stimulating within research and teaching the idea of developing pedagogical benchmark systems. Such bench- marks should illustrate control theory aspects such as stabi- lization of open-loop unstable systems, setpoint tracking, and disturbance rejection [5]. Requested characteristics for these systems are: good illustration of theoretical concepts, good visualization of the physics of the device, low-cost assembly, repeatability, reliability, and easy use and understanding [6]. Among the best-known control laboratory systems are the inverted pendulum and the ball and beam [4]. However, due to the growing interest in control engi- neering, the number of students enrolled in control courses increases each year. This implies a higher financial need for laboratory equipment (need of more pedagogical VOLUME 10, 2022 This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/ 4907