Peg-in-Hole Using Transient Information of Force Response

In precision assembly, a peg is guided into a hole with a tolerance smaller than the position accuracy. Although force/torque sensing can estimate the relative position between the peg and hole accurately, its performance is impaired because of the degradation of estimation accuracy caused by transient error at the time of the collision. We found in this study that if contact state transitions can be generated reproducibly, accurate relative positions can be derived from the transient responses, which were previously regarded as errors. We propose a method that focuses on this characteristic. The transition in the contact state is determined by force/torque responses. Then, the estimation accuracy of the direction of the hole improves by using only the force/torque responses of a specific contact state. Additionally, the time between the contact and estimation of the relative position is reduced by using the transient force information.