Six-Axis Column-Type Force and Moment Sensor for Robotic Applications

A flexible cylindrical beam is used to design a six-axis column-type force and moment sensor for robotic applications, where accurate small force and moment measurements are required. One of the ends of the beam is fixed, and the other remains free. A rigid cover with a mushroom shape is placed at the free end. This cover is the contact surface between the sensor and the object being touched, and it transmits the contact forces and moments to the flexible beam. The 12 miniature strain gauges are strategically placed on the surface of the beam to measure the contact forces and moments by using a simple model based on the classical theory of elasticity. The calibration method of the sensor is performed by using the least-square fitting method, and the experimental results demonstrate that maximum and mean relative errors are below 9% and 3%, respectively, of fullscale in all measured variables.