Sensor Module Combining Time-of-Flight With Self-Capacitance Proximity and Tactile Sensors for Robot

Abstract

Human collaborative robots (HCRs) are a useful future workforce because they can operate alongside people. Proximity and tactile sensing are important for HCRs to ensure safety. In this study, we propose a combined sensor module for HCRs using time-of-flight (ToF) as well as self-capacitance proximity and tactile sensors. The distance to an object in a noncontact range can be detected by a ToF sensor; however, the detection accuracy and the X-Y measurement range are lower for short ranges, with the Z axis as the measurement plane direction. The self-capacitance proximity and tactile sensors can detect objects and contact conditions in short ranges. For high-sensitivity proximity and contact measurements over a large distance, two of the aforementioned sensors can be combined. Prototypes of the sensor modules were prepared, and sixteen modules were mounted on a robot arm to detect the position and distance of an object at 300 mm or less, along with the pressure and position upon contact. In addition, the robot arm was controlled using information obtained from the sensors. The proposed sensor modules can thus be employed for proximity and tactile sensing in HCRs.