Assigning virtual tool dynamics to an industrial robot through an admittance controller

Teaching a task to an industrial robotic manipulator can be done using either programming languages or ldquoteaching by showingrdquo techniques, where the operator drives the robot to prescribed positions using a teach pendant. An evolution of these techniques consists in the operator physically and safely interacting with the robot, by manually guiding its end-effector. Teaching of certain operations like spray painting is much more effective in this way. The present paper addresses this scenario, contributing with an exact formulation of the dynamics of the virtual tool, i.e. the tool whose dynamics the operator should feel when interacting with the robot. An admittance controller driven by the measurements of a force/torque sensor is designed in order to ensure that this virtual dynamic behavior is achieved. Experiments on an industrial robot are shown and discussed.