Three-Axis Tactile
Sensor for Grippers
Research on a three-axis tactile sensor for integration into robotic grippers.
Gripper contact demonstration
The two tactile pads mounted on the gripper are pressed in turn to observe force and contact position. The left panel shows the physical contact; the right panel shows each pad’s contact position, force vector and three-axis time traces.
Electrode array and multichannel electronics
The circular electrode is still divided into three sectors, while the number of groups increases from four to 23. Deformation of the conductive silicone and dielectric under contact load changes the capacitance of each sector.
Sensing electrodes and readout circuits are arranged on a four-layer PCB with six capacitance-to-digital converters. Sensing traces are organized into six active-shield regions.
- Sensing array
- 23 groups / 69 sectors
- PCB / readout
- 4 layers / 6 CDCs
- Power supply
- 5 V
- Communication / output rate
- CAN FD / 100 Hz
- Reported normal-force range
- 0–40 N
- Reported shear-force range
- ±15 N
Sensor fabrication and assembly
The conductive contact layer and dielectric were molded, aligned with the electrode groups, and bonded in place. Calibration was performed after assembly because layer thickness, alignment and bonding conditions affect the signals.
Three-axis comparison with a reference sensor
Normal and two-axis shear loads were applied repeatedly using an AFT150 force/torque sensor as the reference. Reference signals were acquired through IXXAT Classical CAN and tactile signals through PCAN CAN FD, then aligned in time and coordinates.
The reference-loading procedure follows that of the fingertip sensor, with coefficients fitted for the gripper’s channel layout and assembled state. Compression is plotted as negative Fz in the records below.