Robotics
Tactile sensing
Definition
Tactile sensing measures information arising from physical contact, such as contact geometry, deformation, or force. Robots use it to observe interactions at their fingers, grippers, feet, or other contact surfaces.
Also known as: Robot touch sensing
Updated
Contact supplies information that vision may miss
During a grasp, a camera outside the hand may not see the contacting surface. A tactile sensor measures the local interaction itself. The DIGIT project describes a compact sensor designed for robotic in-hand manipulation that captures contact geometry as images.
A tactile measurement can therefore add evidence about a grasp after the fingers touch an object. That evidence differs from recognizing an object before contact.
Some tactile sensors use cameras
Vision-based tactile sensing uses images of a deformable sensing surface to observe contact. DIGIT reports that its images can support normal-force estimation and, with markers, shear-force estimation. The camera is observing the contact sensor's deformation, rather than simply looking at the scene around the robot.
Measurement and interpretation are separate
A sensor image does not automatically provide a calibrated force or a successful grasp. The desired quantity needs an appropriate estimation method, and the sensor must be mounted where relevant contact occurs. DIGIT's platform examples concern particular hands and grippers; they do not establish that every robot has whole-body touch perception. Force control is a separate process that uses measurements or estimates to regulate interaction.
Sources
Related terms
Robotic manipulation
Robotic manipulation is the use of a robot to change an object's position, orientation, or state through physical interaction. It includes grasping and moving objects as well as actions such as pushing or carrying them without a grasp.
Force control
Force control regulates the force or wrench a robot applies to its environment. It may use a robot model, measured interaction forces, or both to produce joint commands that achieve a desired contact load.
Sensor fusion
Sensor fusion combines information from multiple sensors or estimation sources to produce a shared estimate. The combination must account for coordinate frames, timing, uncertainty, and dependence between inputs.