Thick-film multi-DOF force / torque sensor for wrist rehabilitation

A complete six–degree-of-freedom (6-DOF) force / torque sensor has been designed and fabricated for wrist rehabilitation applications, with the focus laid on simple, straightforward manufacturing processes. This paper details the mechanical design, 3D-modeling, manufacture and characterisation of the sensor. Compared to previous work, this design has the advantage of simple, fully planar machining, and the load-sensing elements all lie on the same plane, making the device compatible with single-film deposition or a foil bonding process. The sensor was machined from steel, and the piezoresistive load-sensing bridges were deposited using thick-film technology. We used commercial thick-film materials in a first time. A new lead-free materials system compatible with low processing temperatures (