The arm of TIAGo is composed of the following motors:
4x M90 modules. This self-contained hollow-shaft modules contain brushless DC motors with absolute encoders, integrated power and control electronics and Harmonic Drive reductions. The firmware of the electronic boards implement control PIDs for position, velocity and torque.
1x M3D wrist with 3 DoF made of 3 brushed DC motors with absolute encoders and custom electronic boards. The embedded electronics provide control PIDs for position and velocity.
All the actuators of the arm use CAN-bus for communications. Furthermore, the modules and the wrist include a wide variety of self protection mechanisms (over-temperature, over-current, under-voltage, over-voltage, …).