uSPa 22

Distributed 3-axis Sensing

Each individual sensing point can measure 3-axis touch, not only pressure, but also shear forces. Each sensor module can include up to 64 of those sensing points.

For example, the uSPa 46 includes 4 × 6 = 24 individual sensing points. These sensing points mimic a joystick, measuring X, Y, and Z touch:

• (X, Y) Shear forces tangential to the surface
• (Z) Normal force perpendicular to the surface

Shear force measurements are crucial, for example to measure the weight of an object or detect the onset of slip. Also, the object shape is better reflected in the measurements.

When the grasped object is in contact with three or more sensing points, also the torques (rotational forces) are reflected in the measurements (6-axis force / torque sensing).

The size of the dot indicates the normal force (Z), while the direction of the dot indicates the shear forces (X, Y).