SBIR-STTR Award

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. POTENTIAL COMMERCIAL APPLICATIONS This proposal addresses an application for a new technology, fabrication of a load cell based on embedding a wire sensor inside a composite. Other applications of the basic technology include embedding in composites to monitor internal strain, both initially and as the composite ages. Such sensors can be used to monitor the health of advanced composites used for airframes and space applications, as well as more conventional structures such as buildings, bridges, etc.

___(NOTE: Note: no official Abstract exists of this Phase II projects. Abstract is modified by idi from relevant Phase I data. The specific Phase II work statement and objectives may differ)___ 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. POTENTIAL COMMERCIAL APPLICATIONS This proposal addresses an application for a new technology, fabrication of a load cell based on embedding a wire sensor inside a composite. Other applications of the basic technology include embedding in composites to monitor internal strain, both initially and as the composite ages. Such sensors can be used to monitor the health of advanced composites used for airframes and space applications, as well as more conventional structures such as buildings, bridges, etc.