A Four-Capacitor Tactile Sensor Based on Bump Structure and Compensating Method to Reduce Inertial Interference for Robotic Tactile Sensing

Flexible tactile sensors are essential media for robots to perceive external environments, which give robots human-like senses and enable them to access physical information. However, the force applied on tactile sensor is easy to be distributed unevenly and in motion applications such as human–robot interaction, the tactile sensor will be interfered by inertial force, which both affects the measurement accuracy. Here, we have designed and prepared a flexible four-capacitor tactile sensor with a bump-force conducting structure. By adding a bump-force conducting structure that allows the force acting on the tactile sensor to be evenly distributed to reduce the detection error, furthermore, to address the inertial disturbance, it has been quantified and analyzed and a compensation method by measuring the acceleration signal as a reference has also been proposed. In the simulation and experiment, the inertial disturbance of the tactile sensor was simulated by applying accelerations of different frequencies and amplitudes, and the evaluation results showed a good agreement with the experimental results, which suggests that an alternated acceleration with an effective value of 1.07 m/ $\text{s}^{{2}}$ results in a capacitive change of the tactile sensor with an effective value of approximately 0.33 fF (this corresponds to an effective force of approximately 0.1 mN applied to the sensor). The results show that the inertial disturbance can be reduced by up to 74.11% after signal compensation. This article presents the fabrication of a four-capacitor sensor based on the bump and provides a signal compensation method to reduce inertial interference in a moving environment.