Section: New Results

A serial Architecture for a collaborative robot

The haptic magnifier consists in using a serial architecture, where a motor is inserted between a tool and a user's hand (figure 4 ). By this way, the tool's speed $v_o$ can be changed relatively to user's speed $v_i$, by controlling motor's speed. The haptic rendering of a load can then be changed, and fine details can be more easily detected.

Figure 4. The Haptic Magnifier; (a) the serial architecture with a motor inserted to achieve a haptic magnifier, (b) the implementation with an ultrasonic Motor, and (c) the resulting rendering at load's end and user's end.

The haptic magnifier is built up with an ultrasonic motor, whose characteristic is low speed - high torque. So the tool and the end-effector can be directly connected to the motor, leading to a lightweight architecture. The user's study presented in [21] have shown that the precision in using the tool could be improved during a freehand manipulation.