PROJECT TITLE :

A Limb Compliant Sensing Strategy for Robot Collision Reaction

ABSTRACT:

This paper introduces a compliant limb sensor (CLS) concept for collision detection throughout robot-human contact. The CLS consists of an external rigid shell compliantly connected to the robot link with collision inferred from measured shell displacements. Measuring displacement of a rigid shell allows customizable compliance and high sampling rates due to the tiny number of needed sensors. The proposed sensor is prototyped for the planar case using LED/lightweight-to-voltage (LTV) sensors for shell cause measurement and foam because the compliant link between the shell and base. A physically motivated model for the output of LED/LTV sensor pairs is formulated for the estimation of the shell pose. Voltage measurements of redundant LTVs and a calibrated shell model are used with an iterative optimization routine to estimate the shell pose at high frequencies. Sensor performance is tested using five trajectories: rest, compression, shear, rotation, and arbitrary motion. Experiments confirmed that the CLS will sense the presence, direction, and intensity of impact. The potential application of the proposed sensor to safety in physical human-robot interaction is discussed. The novel sensing methodology also enables a brand new technique of 3-D human-computer interaction because of the power to modify the compliance and operating range of the CLS.