Tactile sensing is currently a research hotspot in the fields of intelligent perception and robotics. The method of converting external stimuli into electrical signals for sensing is a very effective strategy. Herein, we proposed a self-powered, flexible, transparent tactile sensor integrating sliding and proximity sensing (SFTTS). The principle of electrostatic induction and contact electrification is used to achieve tactile response when external objects approach and slide. Experiments show that the material type, speed, and pressure of the perceived object can cause the changes of the electrical signal. In addition, fluorinated ethylene propylene (FEP) is used as the contact electrification layer, and indium tin oxide (ITO) is used as the electrostatic induction electrode to achieve transparency and flexibility of the entire device. By utilizing the transparency characteristics of this sensor to integrate with optical cameras, it is possible to achieve integrated perception of tactile and visual senses. This has great advantages for applications in the field of intelligent perception and is expected to be integrated with different types of optical sensors in the future to achieve multimodal intelligent perception and sensing technology, which will contribute to the intelligence and integration of robot sensing.

Measurement of electrostatic force at the micro-/nanoscale has a great scientific value and engineering significance. This paper develops a new determination method of electrostatic forces based on Kelvin probe force mode in atomic force microscopy (AFM). Applying DC voltage and AC voltage simultaneously, we measured the oscillation amplitudes of the probe at two specific frequencies. By the equivalent parallel-plate capacitor model and the vibration theory, we established quantitative relationship between electrostatic force and AFM raw data, and derived a complete and practical formula for calculating electrostatic force. Then, the fundamental characteristics of electrostatic force with time were revealed, and the changes of all components of electrostatic force with tip–sample distance and applied AC peak voltage were discussed in detail. The regulation effects of the distance and the voltage on the total electrostatic force were also compared. Furthermore, we pointed out the main advantages and disadvantages of this method and stated the applicable conditions of the conclusions according to the experimental results and theoretical analysis.