Publication
Soft force sensors enable closed loop control or autonomous operation of compliant robot systems. A stretchable force sensing surface containing an array of independent sensor units is reported. This design allows for the measurement of local shear and normal forces at multiple locations, independently, providing real-time, multi-axis force information at each unit. The sensor array is based on capacitive strain sensing, using liquid metal electrodes and air microchannel for high sensitivity. Electromechanical interference between adjacent sensor units is addressed and eliminated through design optimization and the use of compliant electrical shield layers. A 1D sensor array is applied to gripping tasks, where the independent sensor readings enable detecting local and partial slipping. This study illustrates how the device can be used to explore the dynamics of local forces during the stages of pick up, slip, and release.|Introducing a soft force sensing surface with electromechanically decoupled units, capable of measuring local shear and normal forces in real time. Combining stretchable electromagnetic shields with liquid metal electrodes, the design minimizes the external as well as internal interferences of neighboring units. Applied to gripping tasks, it detects partial and catastrophic slips, unveiling force dynamics during object manipulation.