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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. [ABSTRACT FROM AUTHOR]

In recent years, human cooperative robots (HCRs) have attracted considerable attention. HCRs should be equipped with proximity and contact sensors to ensure human safety. This study combines time-of-flight (ToF) and self-capacitance sensors to obtain proximity and contact sensors for HCRs. ToF sensor can determine the distance between an object and sensor in the proximity range; however, the detection accuracy decreases in a close range. The self-capacitance proximity sensor can detect objects before and during contact; it has high sensitivity in close range. For proximity measurements with high sensitivity and wide range, it is possible to combine the ToF and self-capacitance sensors. We modularized one sensor and connected the other sensor module using a serial bus; the sensor covered the entire HCR surface to ensure human safety. In this sensor, it is possible to obtain efficient measurements for distance ranging 300–0 mm. The prototype 24 pieces of sensor modules were established on the robot arm and these sensor modules detected the object’s position without establishing any contact and detected the human touch. Additionally, the robot arm was controlled in real time based on the sensor information. We believe the proposed sensor system can be employed as a proximity and contact sensor for HCRs. [ABSTRACT FROM AUTHOR]