Passive Particle Jamming Variable Stiffness Material-Based Flexible Capacitive Stress Sensor With High Sensitivity And Large Measurement Limit

Flexible capacitive stress sensors are important for robotics, human-machine interactions, and electronic skin due to their temperature independence, low power consumption, and high stability. Pressing the soft dielectric material brings the electrodes closer together and thereby increases capacitance. However, the invariance of the elastic modulus of dielectric materials contradicts the sensitivity and measurement limit of capacitive stress sensors. To solve this problem, a passive particle jamming variable stiffness material-based flexible capacitive stress sensor with high sensitivity, large measurement limit is proposed. Applying small stress does not jam the particles, leading to a low elastic modulus (5.2 kPa). As the stress increases, the particles begin to jam and squeeze the elastic cavity, resulting in a jamming phenomenon that gradually increases the elastic modulus (up to 132.4 kPa). Based on this mechanism, a sensor with high sensitivity (0.023 kPa(-1)) and large measurement limit (320 kPa) is demonstrated. In addition, several demonstrations prove the potential applications of the sensor.