Oblique coordinate based micro-macro bilateral control using a piezoelectric cantilever

In this paper, oblique coordinate based micro-macro bilateral control using a piezoelectric cantilever is proposed. Haptic feedback is provided to an operator through the system utilizing a reaction force observer (RFOB) taking hysteresis and linear dynamics of the piezoelectric cantilever into account. Scaling of the position and the force enables operator to manipulate micro objects, and to feel the slight reaction force from the objects. RFOB makes it possible to estimate the reaction force without force sensors. Oblique coordinate based control indicates how to tune the gain ratio between a master robot and slave robot when the actuator of the master robot is different from that of salve. An experiment is conducted to verify the proposed method by using a linear motor and a piezoelectric cantilever. The results showed that the operator could feel the reaction force applied to the slave robot which was scaled up 500 times. It also showed precise position tracking with the error of ±1.1 μm. The force estimation on the piezoelectric cantilever was achieved with error of only ±0.003 N.