2023 ASEE Annual Conference & Exposition

Students’ chemical engineering laboratory experiences are challenging to approximate flexibly, and at low-cost and small-scale. As a result of this challenge and the COVID-19 quarantines, many students were left without adequate experimental experience.

In this paper we present the framework for an Arduino-based system that can be used in varied bench-top process control experiments. These hands-on experiments are used within the context of a lab course taught concurrently with a Process Dynamics and Control theory course and provide an opportunity for students to apply the classroom theory to real systems to enhance their learning. Students gain experience with system identification, digital PID implementation, and PID tuning. Since students are programming their own controller, they gain skills in coding of the microcontroller and practical implementation issues, such as modifications for anti-reset windup and bumpless transfer, as well as control loop troubleshooting. Data acquisition is performed via a Python script that collects Arduino output data for later analysis by the students.

The controller system is adaptable to multiple experiments by utilizing inexpensive and easily available sensors and actuators appropriate to the process to be controlled. Experiments performed include a liquid level controller, a ball-in-tube apparatus position controller, a CSTR concentration controller, a resistive heater temperature controller. Training exercises using a simple LED and light sensor system for controlling light intensity were utilized to quickly get all students comfortable with programming, system identification, and PID implementation. In addition, the controller system is extensible to more than the basic PID algorithm. The programmable nature of the microcontroller allows for the use of alternate controller algorithms, such as feedforward control and nonlinear control. The electronic instrumentation used allows for the use of two sensors and two actuators, allowing for extensions into cascade or MIMO control.

Students were surveyed regarding their experience with these experiments and the overall effect they believe the lab work had on their learning. These survey results are also presented.