Design of an EIT-based flexible tactile sensor with center electrodes

For large area robot skin design, the distribution of rigid components and wires in traditional array sensors leads to the decrease of the flexibility and extensibility. The flexible sensors based on non-invasive electrical impedance tomography (EIT) can avoid these shortcomings. However, the number, position and driving pattern of the central electrode will have a great impact on the performance of the sensor. Multi-walled carbon nanotubes (MWCNTs) are used as filler materials to prepare flexible materials. Different numbers of central electrodes are introduced into the traditional 16-electrode flexible sensor. The corresponding driving pattern is designed and the position error is taken as the evaluation index to carry out comparative experiments. The simulation and experimental results show that the 18-electrode flexible sensor with two central electrodes has the best detection performance, and the detection position error can be reduced by 57.6% at the optimal position of the central electrodes at 0.24 from the center of the circle. The optimal design of the central electrode can effectively improve the performance of the flexible sensor, which has a certain guiding significance for the design of large area robot skin.