A Low-Cost Compact Soft Tactile Sensor with a Multimodal Chip

Research on tactile systems has increased in recent years using arrays of chips to measure data in multiple formats. This work presents an inexpensive tactile sensor capable of providing multimodal data including pressure, gyroscope and accelerometer using one chip only. Polyurethane rubber is used to build a soft rectangular case to cover the chip and trap the air inside the sensor. When the soft rubber is touched, the pressure changes inside the case are measured by the chip and provides the pressure output. The tactile sensor is also mounted on a soft base to measure changes in the orientation of the chip when force is applied on the rubber case. This design approach enlarges the sensitive area of the device and makes it suitable for interaction and control tasks. The response and sensitivity are validated with systematic experiments, which show that sensor can detect small contact forces of 0.02 N. The contact detection is successfully tested with the movement control of the 2-finger RobotiQ gripper in real-time. Perception of contact location using a Universal Robot arm and a probabilistic approach is successfully validated in offline and real-time with accuracy of 100% and 95.8%, respectively. Overall, the results show that this multimodal tactile sensor, inexpensive and composed of one chip only, is suitable for integration in robotic grippers and arms, robot skin design and physical human-robot interaction.