Development of a Real-Time Force and Temperature Sensing System with MEMS-LSI Integrated Tactile Sensors for Next-Generation Robots

Abstract

This study proposes a sensing system that can sense force and temperature at the same time. The system consists of MEMS-LSI integrated tactile sensor devices called sensor nodes, a field-programmable gate array (FPGA) based relay node, and a host PC. For real-time temperature and force data acquisition, a time-sharing force and temperature task processing mechanism was implemented with a dedicated computer architecture in the FPGA configuration and the host program. This study firstly reports the temperature dependency analysis of a capacitive sensor readout circuit in the sensor node by circuit-level simulation. With a fabricated sensor node, sensor output data were measured and analyzed with varying temperatures and applied force. Based on the measured data, linear multiple regression equations for temperature compensation of sensed force data were developed. In the temperature range of 24.8°C–60°C, the average/maximum force errors when considering the temperature effect were −0.98%/65% without the compensation, and 0.072%/17% with the compensation, respectively. One cycle time of temperature and force sensing for one sensor node was 113 ms on average. The experimental results showed that real-time temperature and force sensing and temperature compensation for accurate force sensing could be achieved successfully. The study also demonstrated the system with hot-coffee cup and finger touch examples.