Robotic force/torque sensor with controlled thermal conduction

Abstract

A robotic force/torque (FT) sensor restricts the conduction of heat, generated by an attached tool, through the FT sensor body to a radial direction. Heat from the tool is channeled to the center of the FT sensor body by a thermally conductive member. Additionally, heat from the tool is insulated from portions of the FT sensor body other than its center by a thermally insulating member. Transducers, such as strain gages attached to the surfaces of deformable beams, are disposed at a substantially equal distance from the center of the FT sensor body. Accordingly, as heat conducts through the FT sensor body from the center radially outwardly, all transducers experience substantially equal thermal load at any given time. Embodiments of the present invention substantially eliminate thermal gradients across groups of transducers that are wired in differential circuit topologies, such as half-bridge or quarter-bridge, enhancing the ability of such circuits to reject a common-mode signal component caused by thermal changes to the FT sensor body or the transducers themselves. Elimination of thermal gradients in the FT sensor body, other than one in the radial direction, enhances the effectiveness of known temperature compensation techniques.