How can a robot feel what it holds?
Cameras see the scene. Touch sensors can reveal what happens at contact.
Connect contact, friction and sensing without confusing a model with a measurement.
Contact matters
An object may look secure while slipping between the fingers. Contact measurements can help a controller adjust its grasp. Useful information may include force, pressure patterns or surface deformation.
Different sensors, different information
Some tactile sensors use cameras to observe a deformable surface. Others measure force or pressure through different mechanisms. Coverage, sampling, calibration and durability matter as much as a sensor count.
Look for the feedback loop
When you watch a gentle grasp, ask whether touch data actually changes the motion. A hand containing sensors is not proof that a demonstrated task uses them.
Try it yourself
CONTACT LAB · ideal symmetric pinch
Will the friction budget cover the weight?
Two opposing contacts each apply normal force N. In this static Coulomb model, total tangential capacity is 2μN; weight is mg.
Teaching example only. Equal rigid contacts, known friction, no acceleration or torque. A sufficient budget does not establish a stable or gentle real grasp. These are not hardware force settings.
Your practical task
- In the pinch model, lower friction while leaving mass and force unchanged.
- Observe when the friction budget becomes smaller than the object’s weight.
- Name a measurement that could help detect a grasp beginning to fail.
What to produce: An explanation of one failure and the sensor signal you would investigate.
Check your understanding
Original sources & next steps
Shadow Robot: sensing on DEX-EE ↗MIT Robotic Manipulation: contact and force control ↗Original Dexhands teaching material. Interactive models and added references reviewed September 23, 2026; the introductory reading retains its September 22 review. Research links are not endorsements or evidence of hardware compatibility.