The primary incentive for this project is the development of a versatile type of mechanical force sensor for applications in haptics and robotics. Nearly all sensors to date can be categorized into two types. One measures direction and magnitude of force at a single point, but cannot measure its distribution. The other measures the distribution of the magnitude of force, but cannot measure its direction. The force sensor we have developed integrates these two types to measure the distribution of force vectors, with both magnitude and direction.
The sensor consists of a transparent elastic body, and two layers of colored markers within the body. When a force is applied on the body's surface, we optically measure the internal strain of the body through the movement of the markers. Finally, force vectors are calculated from the strain using elastic theory.