FOC-controlled haptic knob for industrial robot programming with force feedback

abstract

Robot programming is still an elaborate process in industrial assembly, especially in cases requiring a specific force profile for successfully executing an assembly step. In this work, we present the Haptic Knob, a low-cost haptic device (around 100 EUR on hardware costs) for (currently) one-dimensional robot movement programming on both position and force profiles. The Haptic Knob is equipped with a Field-Oriented Controlled (FOC) motor and a positional encoder that reads the human input position and generates feedback forces to the operator. The Haptic Knob is not equipped with an external Force/Torque sensor to measure the human input force, but works together with the impedance controller of the robot arm, which allows a dynamic force teach-in. A control interface is implemented to map the positional signal from the Haptic Knob to the movement of different actuators, as well as the force/torque signals from various devices to the Haptic Knob for force feedback. We showcase and validate the proposed hardware and control interface on the industrial use case of automotive fuse box assembly.