Compact robotic force/torque sensor including strain gages

Abstract

A force/torque sensor comprising a Tool Adapter Plate (TAP) connected to a Mounting Adapter Plate (TAP) by one or more radially-spaced, deformable beams features a pair of strain gages affixed to only one surface of each beam. The two strain gages are affixed to, e.g., the top surface on either side of, and spaced away from, a neutral axis of the beam. This enables a very compact sensor design, in one embodiment, machined from a single piece of metal stock. The two sensors may be connected in a quarter bridge topology. In one embodiment, another pair of strain gages is affixed to the same side of the beam, and the four gages are wired in a half-bridge topology. In another embodiment, a second pair of strain gages is affixed to the opposite side of the beam, and the four gages are wired in a half-bridge topology—although this embodiment gives up some of the space and ease of manufacture advantages, it allows for electrical elimination of common-mode signal components, such as those induced by temperature drift. In one embodiment, a strain gage is connected to a non-stressed member of the sensorto provide a signal for temperature calibration.