Adaptive Fuzzy Sliding Mode Control for High-Precision Motion Tracking of a Multi-DOF Micro/Nano Manipulator

This letter 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.