COLLISION HANDLING BY A ROBOT

The invention relates to a method of collision handling for a robot with a kinematic chain structure comprising at least one kinematic chain, wherein the kinematic chain structure includes: a base, links, joints connecting the links, actuators and at least one end-effector, a sensor Sdistal.i in the most distal link of at least one of the kinematic chains for measuring/estimating force/torque, and sensors Si for measuring/estimating proprioceptive data, wherein the sensors Si are arbitrarily positioned along the kinematic chain structure, the method including: providing a model describing the dynamics of the robot; measuring and/or estimating with sensor Sdistal.i force/torque Fext,S.distal.i in the most distal link of at least one of the kinematic chains; measuring and/or estimating with the sensors Si proprioceptive data: base and robot generalized coordinates q(t) and their time derivative {dot over (q)}(t), generalized joint motor forces τm, external forces FS, a base orientation φB(t) and a base velocity {dot over (x)}(t)B; generating an estimate {circumflex over (τ)}∈ of the generalized external forces τext with a momentum observer based on at least one of the proprioceptive data and the model; generating an estimate {umlaut over ({circumflex over (q)})}(t) of a second derivative of base and robot generalized coordinates {umlaut over (q)}(t), based on {circumflex over (τ)}∈ and τm; estimating a Cartesian acceleration {umlaut over ({circumflex over (x)})}D of point D on the kinematic chain structure based on {umlaut over ({circumflex over (q)})}(t); compensating the external forces FD for rigid body dynamics effects based on {umlaut over ({circumflex over (x)})}D and for gravity effects to obtain an estimated external wrench {circumflex over (F)}ext,S.i; compensating {circumflex over (τ)}∈ for the Jacobian JS.distal.iT transformed Fext,S.distal.i to obtain an estimation {circumflex over (τ)}ext,col of generalized joint forces originating from unexpected collisions; detecting a collision based on given thresholds τthresh and FS.i,thresh if {circumflex over (τ)}ext,col>τthresh and/or if {circumflex over (F)}ext,S.i>FS.i,thresh.