The Simulation Experimental Lab (SEL) in Gemini South currently houses 22 setups that Mechanical Engineering (ME) students and Applied Physics students are working with, in 58 mixed groups consisting of five Mechanical Engineering and three Physics students. Their assignment is to devise an application for a so-called Pick and Place robot. Examples include stacking, sorting, and transporting objects, such as watches, packages of matches, apples, or anything else for that matter. With a suction cup, the object can be lifted from a conveyor belt as big as a keyboard and as green as a billiards table. The robotic arm then moves the object, making sure it ends up exactly in the intended final position. This may be a compartment within a package, for example, or a large bin for selecting rejected items. Whatever the students come up with, basically.

Practical course

All of this teaches them to turn previously learned theory into practice. “They start by measuring the FRF (frequency response function) of the robot and then they design a feedback controller and – possibly – a feedforward one. After that, students start experimenting with Matlab Simulink, simultaneously learning to work together in interdisciplinary groups,” says Gerard van Hattum. The mechanical engineering lecturer has been teaching the course ‘Control of a Flexible Robot System’ for years, but this is the first time there are also physics students there. They don’t have the same prior knowledge as ME students, but that’s precisely what makes the whole thing so educational. “Working together in multidisciplinary groups is a core CBL concept, enabling students to learn from each other,” says lecturer Rudie Kunnen, co-responsible on behalf of Applied Physics.

Van Hattum knows from experience that students find this a very difficult course, but afterwards they usually say that they learned a lot from it. But why should you, as a physicist, actually be able to control a robotic arm? Kunnen is clear about that: “It may be that you come across the underlying field, control engineering, in your work and then it’s good to have experimented with it. And collaborating is something you have to do in every job.”

Students are assessed based on their experimentation plan, the poster and video (of max 1 minute) they produce, and the 20-minute discussion in which they justify their choices to a number of lecturers. CBL coordinator of Mechanical Engineering Marieke Postema explains that students themselves prioritize speed, accuracy, or originality. 

Tower of Hanoi

The group Jesper Fidder (ME student) is in wants to program the robotic arm in such a way it can distinguish between ripe and rotten apples. “First based on color, which is possible because there’s a camera with the robot setup. And later, possibly, based on texture. The pick-up suction cup should then detect whether the apple is soft or still firm. We’re focusing on accuracy for now, possibly switching to speed later on.” Fidder likes that he can now apply the theory he picked up in Q2.