The LEGO devices of the robotic cell
The set of LEGO modules includes four devices:
- A turntable of a 40cm diameter with a see-though wall in the middle. The turntable can rotate by half turn back and forth.
- A centering table which is a passive tilted table (with no actuators or sensors) that allows the blank parts to be squared-up by sliding down to the bottom corner of the table edge.
- A C-type press that can exert the enough force to stamp a message on a blank visit card. The press incorporates a self-inking stamp with weakened springs, equipped with a custom-made matrix. The press ram moves up and down smoothly thanks to a position, speed and acceleration controller that drives the LEGO MINDSTORMS servomotors.
- A linear conveyor that carries the finished cards out of the cell, into a basket.
In real-sized robotic stamping cells, the robots and the metal parts to be moved are big and heavy, so there’s a potential hazard for humans. The press itself can exert tons of pressure. Instead, all the LEGO devices of the robotic cell model are inherently safe, the torque of the motors is low, and the press “tonnage” is just few kilograms. This makes this robotic cell model ideal for safe training of operators.
In the past, in the field of industrial process simulation, I realized LEGO car factories with many robots and moving parts, and complex software behind their smooth operation. Compared to those projects, the movements of these LEGO devices is quite simple: turn clockwise/counterclockwise, go down and up again, turn for a certain amount of time. The design requirements that made this work challenging and interesting are that the various modules had to be interfaced with an industrial PLC, and that we could swap them with real peripherals in a plug-and-play manner, being them compatible at electric level and at hardware connector level. Also, the various devices were designed to look uniform in shape and color scheme with the real ABB machines. In particular, the key specification for the press was that it should look “sexy”, so I designed it as curvy as possible.