How do robots use force and torque sensors?

Robots use force and torque sensors to measure and respond to physical interactions with their environment. Force sensors detect linear forces (push/pull), while torque sensors measure rotational forces (twist). These sensors are integrated into robotic systems—often at joints, grippers, or end-effectors—to provide real-time feedback about contact forces. This data enables robots to adjust their movements dynamically, ensuring precise control during tasks that require physical interaction. For example, collaborative robots (cobots) use these sensors to detect unexpected resistance, such as contact with a human, and immediately reduce force to ensure safety.

In industrial applications, force and torque sensors are critical for tasks demanding accuracy. A common use case is assembly, where a robot must insert a part into a tight space without damaging components. By monitoring force feedback, the robot can sense misalignment and correct its approach. Similarly, in precision tasks like polishing or grinding, torque sensors help maintain consistent pressure. Surgical robots also rely on these sensors: when suturing tissue, the system must apply just enough force to avoid tearing. The sensors feed data to the robot’s control system, which adjusts motor outputs to achieve the desired behavior. This closed-loop control is essential for handling materials with variable properties, like soft or deformable objects.

For developers, integrating force and torque sensors involves both hardware and software considerations. Sensors typically communicate via analog signals or digital protocols (e.g., SPI, I2C) and require calibration to map raw readings to physical units. Software libraries often handle filtering noise and converting sensor data into actionable inputs for motion controllers. For instance, a robot arm gripping an object might use torque feedback to detect slippage and increase grip force proportionally. Developers must also design fault-tolerant systems—if a sensor fails, the robot should default to a safe mode. By leveraging these sensors, robots gain adaptability, enabling applications in unstructured environments where preprogrammed paths are insufficient.