Instructional laboratories are a common part of undergraduate engineering education. Historically, these laboratories have taken place on campus with expensive equipment. However, with the rise in popularity of online classes and low cost hardware there are new alternatives to the traditional on-campus instructional laboratory. This research developed a modular, portable, and affordable laboratory kit to support the accompanying curriculum for the introductory controls course in the general engineering (GE) program at the University of Illinois at Urbana-Champaign. The objective was to design each kit to be assembled for around $100 while replicating the educational functionality of a lab bench in a university controls laboratory. A kit will also allow older analog computers to be updated with newer technology that is more representative of what is currently used in industry [1
]. Replacing expensive equipment with an affordable kit that can be shipped anywhere in the world increases the accessibility of the controls laboratory experience for students on campus and remote locations. Previous research shows that hands-on laboratory experiments help students understand and apply course material [2
Some affordable and transportable laboratory devices for engineering education have already been developed, such as the Mobile Studio IOBoard, which is centered on a custom-built board that “replicates the functionality of an oscilloscope, function generator, multimeter, and power supplies” and is primarily used in introductory circuits courses [3
The target course for the kit is GE 320 (an introduction to control systems for general engineering students). This course is representative of the first course in controls for many electrical, mechanical, and aerospace engineering programs. The kit design consists of a Raspberry Pi (a fully functional ARM-based computer that is the size of a deck of cards), a DC motor, and the various circuits required to drive the motor, to measure position and speed, and perform system identification.
The need for laboratory experiences in control systems courses has been well established in [4
] and others, however there are challenges associated with including them. Some hurdles include: budget constraints, space limitations, class size, and limited teaching resources [5
]. Additionally, the increasing popularity of online courses has added a new consideration for laboratories [4
The literature shows that the cost of equipment per laboratory station varies from $180 [13
] to $32,493.74 [14
]. This research looks to replace the basic functionality of these laboratories with an affordable kit. The target budget of $100 for the kit was used because it is the approximate cost of a textbook. The budget is also only three times the cost of an iClicker, another common piece of technology that students purchase for courses, and the approximate cost of other low-cost kits for other courses found in literature [3
]. The Arduino prototyping kit described in [15
] is approximately $95 and was designed for a multidisciplinary course on perception, light, and semiconductors. The Mobile Studio IOBoard described in [3
] has multiple versions ranging in price from $80–$130. The primary application of the Mobile Studio IOBoard is undergraduate circuits courses.
In addition to monetary cost, dedicated laboratory space is also limited and class sizes are increasing. These factors place restrictions on the capabilities of face-to-face laboratories. Not all students can attend and complete face-to-face laboratory experiments due to time, location, or physical disability [16
]. An alternative to face-to-face laboratory experiences are laboratory kits.
A lab kit allows students to take home the laboratory equipment to complete the experiments on their own time [13
]. These kits started to become more popular as the cost of the required hardware has decreased [15
]. The kits’ contents vary based on the objectives of the course and can be assembled by the instructor [8
], adapted from an existing kit [13
] or purchased as a complete kit such as Lego Mindstorms NXT [17
]. These kits have been well received by students [8
The science and engineering active learning (SEAL) system created a take-home kit for students to develop a cart with an inverted pendulum attachment [8
]. It was designed to be used in controls courses. The cost of the kit is approximately $100 plus $179 for a myDAQ from National Instruments [8
]. The MESAbox was also designed for controls and mechatronics courses; it uses an Arduino and costs approximately $180 [13
]. The MESABox kit includes multiple motors and sensors and is based on an off-the-shelf kit from Sparkfun; however, this includes more components than required for the GE courses. The laboratory experiments designed for the MESABox cover a variety of controls topics including using the Arduino programming language and wiring all of the circuits.
The DC Motor control equipment detailed in [6
] includes $80 of hardware and a motor, gearbox, and encoder. The cost of the latter three components are not included; the motor manufacturer’s website indicates these components are more than $100 each [20
]. The total cost for each station with this equipment is approximately $400 and it is not designed to be portable.
All undergraduate laboratory experiences still need to meet the course goals and objectives as well as ABET accreditation requirements [7
]. There are several goals that can be applied to laboratory experiences based on the outcomes in the ABET Criterion; a student should have the ability to conduct experiments, analyze and interpret data, use modern engineering tools, design experiments, solve engineering problems, and function in teams [21
]. In general, the controls laboratory experience should prepare students for a career in control systems [1
] by performing the following steps: building the system [5
], modeling and analyzing the system, developing a controller to meet performance requirements, simulating the controller and system, observing the physical system, collecting the data, and using the data to improve the system model or control tuning [4
]. Experiments based on DC motors [6
] have been identified to meet these goals for controls laboratory experiences. Another advantage of using a DC motor for a control systems laboratories is the range of experiments that are possible. One example is a simple proportional-integral-derivative (PID) control of the motor’s position [22
]. A more complex example is to add an attachment to make an inverted pendulum [6
There were four primary considerations driving the development of this kit: achieve the same educational objectives as the current laboratory equipment, cost and accessibility of parts, portability of the complete kit, and student interface. Within the first consideration, it was important to have a seamless transition in the laboratory without changing the lecture part of the course.
A budget of approximately $100 and the desire to be able to quickly obtain replacement parts if something breaks drove the second consideration of cost and availability of parts. The budget is similar to other kits found in the literature and approximately the same cost as a textbook. All of the parts in the kit are available at major online retailers or 3D printed.
Cost and accessibility is also closely tied with the third consideration of portability. Portability is a long-term goal of the project, so that the students can take the kits home or the kits can be shipped to students taking online courses.
The last consideration, student interface, placed the most restrictions on the current design of the kit. The lecture portion of the course and some of the existing laboratory experiments use MATLAB and Simulink as the simulation and development platform. Therefore the new kit uses MATLAB and Simulink as well. At the start of the development of the kit only two small, low-cost, hardware platforms had Simulink support: Arduino and Raspberry Pi. The latter was chosen for its flexibility and potential to expand into other controls courses with more complex algorithms and possibly object tracking via video.