Figure 6.

An experiment is designed to calibrate the sensors while the participants are wearing the sensorized interface. Participants are asked to lift a jerrycan up and down, at a self selected speed. The pressure readings are compared to the external forces acting on the end-effector to calibrate the sensors. $F_1$, $F_2$, $F_3$ and $F_4$ are the forces measured by the four sensors, $F_{ext}$ is the force measured at the end-effector, x(t), y and z(t) are the spatial coordinates of the end-effector. The motion of the robot is constrained to the xz-plane, such that y remains constant.