Ultra Low-Noise FPGA-Based Six-Axis Optical Force-Torque Sensor: Hardware and Software

In this article, we present the novel hardware and software architecture of a smart optical force-torque sensor. The proposed configurable, modular, and compact electronics lead to performance characteristics that cannot be reached by currently available sensors: ultra-low noise with average noise power spectral density of 15 nV/root Hz over a signal bandwidth of 500 Hz, a resolution of 0.0001% full scale at a 95% confidence level, and a hardware latency of less than 100 mu s. Performance is achieved by local synchronized oversampling of the sensor's optical transducers and parallel hardware processing of the sensor data using a field-programmable gate array (FPGA). The FPGA's reconfigurability provides for easy customization and updates; for example, by increasing the FPGA system clock rate to a maximum of 160 MHz, latency can be decreased to 50 mu s, limited by the current analog-to-digital converter. Furthermore, the approach is generic and could be duplicated with other types of transducers. An inertial measurement unit and a temperature sensor are integrated into the sensor electronics for gravity, inertia, and temperature compensations. Two software development kits that allow for the use of the sensor and its integration into the robot operating system have been developed and are discussed.

Automated summary

The article introduces a novel hardware and software architecture for a smart optical force-torque sensor. The use of configurable, modular, and compact electronics leads to unparalleled performance characteristics, such as ultra-low noise and high resolution. Performance is achieved through oversampling of optical transducers and parallel hardware processing using FPGA, with additional features like an inertial measurement unit and temperature sensor integrated for improved compensation.