A torque sensor is a transducer that measures the rotational force, or torque, applied about an axis, commonly at a robot joint or drive shaft. By reporting the load a joint experiences, it enables force control, compliance, collision detection, and safe physical interaction between robots and humans. Torque sensors typically use strain gauges bonded to a deformable element whose deflection is proportional to the applied moment.
Overview
- Torque sensing closes the loop between a robot’s intended motion and the forces it actually exerts, turning a position-controlled machine into one that can feel and respond to contact. Mounted at each joint, torque sensors let a manipulator detect unexpected collisions, regulate grip strength, and yield safely when a person pushes against it. This proprioceptive feedback is foundational for collaborative robots that share workspace with humans.
Key aspects
- Strain-gauge bridges that convert mechanical deflection to electrical signal
- Joint-level versus end-effector (wrist) torque measurement
- Temperature compensation and calibration for measurement accuracy
- Integration with feedback control loops for compliance and impedance control
- Collision detection via deviation between commanded and measured torque
Applications
- Compliant control of collaborative robot arms
- Force-limited assembly and insertion tasks
- Safe human-robot interaction and collision response
- Haptic and teleoperation systems requiring force reflection