This paper introduces a robust adaptive control methodology for piezo-actuated flexure-based micro/nano manipulation mechanisms. This special control approach is established for tracking of the desired complex motion trajectories with system uncertainties. Further, the control methodology is formulated to accommodate not only the system uncertainties but also nonlinearities including the hysteresis effect and external disturbances in the motion of a 3-degrees-of-freedom (3-DOF) XYZ micro/nano manipulator. Adaptive fuzzy sliding mode control (AFSMC) is developed for the formulation of the control methodology. The fuzzy logic component and adaptation law employed in the controller are used to approximate the system uncertainties and compensate for the effect of nonlinear terms in the system. The resulting control strategy is devised using a sliding mode control scheme. The asymptotic tracking ability of the designed controller is proved by using Lyapunov-based stability analysis. Furthermore, an experimental study is performed on the 3-DOF compliant monolithic parallel micro/nano manipulator and the results confirm that the designed control approach produces high-precision motion tracking and smaller tracking errors compared to a model-free control technique, i.e. Proportional-Integral-Derivative (PID) controller.

The demand for high precision micro/nano manipulation is increasing for advanced manufacturing technology. The precise motion of the microgripper jaw is required to achieve high performance micromanipulation tasks. The parasitic motion of the microgripper reduces placement accuracy during pick and place tasks. This paper presents an asymmetric design of piezoelectric actuated microgripper. It investigates key characteristics including parasitic motion, output displacement, and displacement amplification ratio. The microgripper is designed with a single-stage displacement amplification mechanism to form a compact layout. The design of the microgripper integrates the bridge-type mechanism and the parallelogram mechanisms. The bridge-type mechanism amplifies the piezoelectric actuator output and the parallelogram mechanisms offer linear motion of the gripper jaw. The analytical modeling and finite element analysis were conducted to evaluate the characteristics of the microgripper. The design parameters of the microgripper were optimized through several finite element analysis. Further, experimental studies were conducted to verify the characteristics of the microgripper. The parasitic motion of the jaw was obtained as less than 0.18% of the microgripper jaw motion in the x -direction. The mechanism of the microgripper also achieves a high positioning accuracy. Further, a high displacement amplification ratio and large output displacement can be achieved.