High-Speed High-Precision Proximity Sensor for Detection of Tilt, Distance, and Contact

Abstract

We developed a fingertip-size proximity sensor that detects the distance to and the tilt angle of the surface of an object with the peak-to-peak distance error less than 1/129th (<;31 μm) and the measuring time less than 1/10th (<;1 ms) those of existing sensors. In addition, we realized the task of catching a fragile object (paper balloon) with a high-speed robot hand equipped with the sensor. High-speed, high-precision sensing enables contact detection independently of the contact force. We describe a robust contact detection method that does not depend on the reflectance, the tilt angle, or the shape of target objects surface. In experiments, we confirmed that the sensor could measure a distance of 2.85-20 mm (resolution: 44 μm in <;3 mm) and a tilt angle of ±45° (error: 1.47°) for objects with reflectances of 18% and 90%. We demonstrated that the hand could catch the paper balloon when dropped from a height of about 20 cm without crushing it.