Tactile Sensor Research Report, 2025

The `Tactile Sensor Research Report, 2025` conducts research, analysis and summary on the basic concepts, technical principles, advantages and disadvantages of different technical routes, technical development trends, applications of tactile sensors (including robotic dexterous hands, electronic skin, automobiles, industrial automation, smart homes, etc.), domestic suppliers and their products, and foreign suppliers and their products.

Tactile sensors are devices that can perceive and measure tactile information such as surface normal force (pressure), tangential force, temperature, hardness, and texture. According to the sensing principle, they can be divided into piezoresistive sensors, capacitive sensors, piezoelectric sensors, visual-tactile sensors, magnetoelectric (Hall) sensors, and photoelectric sensors.

Various Technical Routes of Tactile Sensors Flourish

The six types of tactile sensors based on different principles - piezoresistive, capacitive, piezoelectric, visual-tactile, magnetoelectric (Hall), and photoelectric - each have their own advantages, attracting many scholars and enterprises to conduct research. At present, various technical routes of tactile sensors are flourishing and have not converged.

Among them, the principle of the piezoresistive tactile sensor is that the force changes the resistance value of the conductive material, and the change in external pressure or contact state is reflected by detecting the change in resistance. Due to the low manufacturing cost of piezoresistive sensors, they are currently the most widely used. Typical suppliers include Hanwei Electronics - Leanstar, Moxian Technology, PhlexSense, and Fulai New Materials.

Capacitive tactile sensors obtain force information based on capacitance changes caused by external stimuli. Capacitive tactile sensors have higher spatial resolution and sensitivity than resistive tactile sensors, are easy to integrate in arrays, and can measure three-dimensional forces. In addition, capacitive tactile sensors are the only tactile sensors that can measure proximity perception, with many researchers at home and abroad. Representative suppliers include Hanwei Electronics - Leanstar, Tashan Technology, Sycsense, New Degree Technology, TacSense Technology, PPS, and Baumer.

Principle of piezoelectric tactile sensors: The force applied to the device deforms the piezoelectric material, causing charge polarization inside the material and opposite charges on the surface of the material. This effect can be used to detect external stimuli (such as pressure, vibration, etc.). Piezoelectric tactile sensors have a wide range and high signal linearity, but the acquisition circuit is slightly complex. At present, foreign suppliers are dominant, such as Tekscan, JDI, and Novasentis.

Vision-based tactile sensors can be analogous to miniature `contact imaging systems` and achieve high spatial resolution and a wide dynamic response range using optical principles. For example, the GelSight vision-based tactile sensor is based on the principle of photometric stereo. It identifies the morphological changes caused by the compression of the soft elastomer on the textured surface, amplifies the micro deformation and converts it into a clear image, that is, it infers the force change by photographing the deformation of the image. Domestic suppliers include Tashan Technology, Daimon Robotics, ViTai Robotics, etc.

Magnetoelectric (Hall-effect) tactile sensors utilize the Hall effect to convert input force into induced electromotive force for output. They have a fast response speed, reaching the millisecond level. The principle of photoelectric tactile sensors is that external pressure changes the optical properties of the medium, the light propagation path, and the intensity of transmitted light, converting changes in optical signals into electrical signals to realize the perception of tactile information such as pressure. Photoelectric tactile sensors can achieve multimodal perception, including the detection of various tactile features such as pressure, hardness, vibration, and sliding.

Integration of multi-perception technology routes to meet multi-dimensional needs

In practical applications, tactile sensors need to meet the needs of multi-dimensional information perception such as pressure, temperature, humidity, and material identification. For example, when a robot grabs an object, it needs to use `force-temperature-texture` multimodal perception to identify whether the object is slipping (force change), whether it is at a high temperature (temperature), and whether it is fragile (hardness); the skin of medical rehabilitation prosthetics needs to simultaneously perceive pressure (to avoid pressure ulcers), temperature (to prevent scalds), humidity (to monitor skin conditions), etc.

However, a single technical route (such as resistive, capacitive) is difficult to cover all needs, so it is necessary to achieve the effect of `1 + 1 > 2` through integration. The integration of multi-sensing technology routes is the core means to realize multimodal perception of tactile sensors. By integrating technologies with different principles, materials or structures, the sensor can simultaneously perceive multiple physical quantities such as force, temperature, humidity, texture, and hardness.

Tashan Technology's TS-V visual-tactile fusion technology platform integrates binocular vision-based tactile and capacitive tactile perception, achieving a three-dimensional force measurement accuracy of 0.01N, a resolution of 1mm, and can identify more than 30 different materials. It also has proximity perception, with an air perception distance of 2cm.

Tactile sensors enable robots to have human-like perception

Tactile sensors can bring human-like perception capabilities to robots, simulating the skin's perception of external stimuli such as pressure, friction, and strain. They can also perceive physical properties of target objects such as hardness, texture, temperature, and humidity, and convert these physical signals into electrical signals, ultimately achieving precise interaction with the external environment.

The installation positions of tactile sensors in robots are around the `core area of physical interaction`, and their core role is to ensure safety and improve operation accuracy. Currently, tactile sensors in the robotics field are mainly applied to the end of robotic hands and the fingertips of dexterous hands, and some have extended to the finger pads and palms. In the future, they will be applied to robotic arms/arms, lower limbs, trunks and cover the whole body.