High Dynamic Range Force Torque Sensor

A force-torque sensor concept with a high-dynamic range achieved by implementing a multiple flexure design. In this approach, the first smaller set of flexures is attached between the two sensor bodies while another larger flexure set is attached at one body and encapsulated/contained in the other. A gap in the encapsulation/containment allows for the first flexure to deflect freely under specific loads measuring six-axis force and torque before the other set is engaged. Once engaged, the second deflects providing support to the first flexure set and measures six-axis force and torque. This unique multiple flexure design allows for accurate measurement at low loads via the smaller flexure and at high loads via the combined stiffness and deflection measurements of both flexures. Loads are measured utilized stain gauges and method standard to current force-torque sensors adapted to this unique multiple flexure design. Funding shall be utilized to validate the multiple flexure force-torque concept and compare its dynamic range against standard single flexure designs. Prototypes shall be developed and tested to aid in validation and comparison. Target markets include mechanisms and robotics for lunar, cislunar, and earth orbit. Additional markets include terrestrial robotics and mechanisms.
Benefits: The emergence of a lunar space economy and increase in robotics in cislunar, lunar, and earth orbit has led to an increased need for robotics and subsequently force-torque sensors. Specifically, the need for sensors with a high-dynamic range that can survive launch loads and dynamic operational loads while providing required sensitivity and accuracy for the desired mission. Satellite servicing, debris removal, persistent platforms, commercial space stations, commercial lunar operations, space exploration, and lunar development/resource utilization all drive the need for a high dynamic force torque sensor. Current standard market offerings are limited due to the single set of flexures. These offerings struggle to accurately measure both small and very large forces and torques. This limited dynamic range can hinder precision tasks and the ability to handle unexpected impacts or loads. To provide accurate results of low loads, the flexure needs to be delicate. However, they will eventually deform and break under higher force and torques. To withstand higher loads, the flexures need to be made more robust which results in poor low range measurements with large relative tolerances. Unlike those solutions, the unique multiple flexure design allows accurate results over a high-dynamic-range of loads without sacrificing accuracy performance. The first set is continuously engaged and provides readings over lower loads while additional sets provide readings over higher levels of loads. This approach provides measurements over a high-dynamic range while providing the needed measurement tolerance at each range and preventing the deformation or breaking of any set of flexures. This concept makes force-torque sensors more robust and able to withstand dynamic loads from launch and operation unknowns without damage or loss of accuracy, essential for robust sensing in cislunar, lunar, and earth orbit mechanisms and robotics. Potential non-NASA applications include terrestrial robotics involved in industrial uses such as assembly lines, pick and place, warehouses, etc.