Novel Force Sensor for Robotics

Measuring small loads in small cable/wires is needed to sense force or torque in robotic joints. Load monitoring is normally done using a load cell with strain gauges, which have a low-level output and requires a rigid structure for the strain gauge attachment, resulting in a bulky structure where space is at a premium. In addition, the low level signal requires extensive signal conditioning in the often electrically noisy environment.The proposed system is based on a new sensor technology, consisting of a stress sensitive wire that can be embedded or cast at the center of a structure. This composite with the sensor wire now becomes a flexible load cell, with load ranges based on the composite size. In addition, the output is at higher level from a low impedance source, giving the system good noise immunity. Since the sensor is magnetic-based, it is possible to excite and detect the signal without physical contact if desired to give even more flexibility.The use of a flexible force transducer is a novel and unique approach, only possible with this new sensor. This approach can also be modified to measure torque, flexing and vibration as well as loads.