Displacement Sensor Integrated into a Remote Center Compliance Device for a Robotic Assembly

Compliance devices facilitate robotic assemblies by preventing excessive contact force on automated devices. However, the unavailability of displacement information regarding compliance devices makes it difficult to protect robots and objects during robotic assembly. It also limits repeatability and efficiency, especially regarding peg-in-hole and similar operations. We propose a six-axis displacement sensor installed on a remote center compliance device to detect the three translation and three rotation components generated by external forces and torques applied to the device, respectively. Triangular prism-shaped structures are used with capacitive sensing technology to measure the vertical and horizontal displacements in mm scale generated by the external normal and shear forces applied to the sensor. We designed and fabricated the sensor that could be integrated into a remote center compliance device, demonstrating it has a simple structure and is easy to install. To obtain six-axis force/torque information and six-axis displacement, calibration experiments were conducted using a specific setup and considering the device's geometry. The high sensing performance was verified through complementary experiments.