This study presents new pose sensing and servo control techniques for the compliant nanopositioners (CNPs) based on optical microscopic vision. A visual pose tracking algorithm (VPTA) and a visual servo positioning scheme (VSPS) that both utilize iterative template matching are presented. In the VPTA, to realize pose sensing of the CNPs with high performance, an improved Gaussian-Newton optimization method combined with an adaptive penalty strategy is developed. In the VSPS, to realize robust and flexible control of the CNPs, a velocity controller that directly uses the gray value of the template to control the CNP is designed. Simulations and experiments are performed to demonstrate the performance of the proposed method. Results show that the VPTA can achieve pose tracking of the three-degree-of-freedom (x,y,θ) CNPs at a frame rate of hundreds of hertz, and the dynamic tracking errors are smaller than 100 nm, 160 nm, and 40 urad in the x-, y-, and θ-axes, respectively. Moreover, by using the proposed VSPS, task-based nanopositioning can be easily realized without extracting features of the object, and the obtained stable positioning accuracies are better than 30 nm, 33 nm, 3 urad in the x-, y-, and θ-axes, respectively.

Stepping motion principle has been widely applied for piezoelectric actuators. A stepping-motion actuator driven by a compliant mechanism is proposed in this paper. Two degrees of freedom exist in the compliant mechanism, which offer the possibility for multiple actuation modes including stick-slip mode, semi-inchworm mode, and pseudo-ultrasonic mode. Actuation trajectories are planned according to the geometric model of the compliant mechanism and proven efficient. The dynamic characteristics of the compliant mechanism is concerned and its modal finite element analysis is performed. The performances of the actuation modes are verified in experiments. A brief verification of angular stick-slip mode, which improves the output force by 155.3% compared to stick-slip mode, is carried out. An actuation frequency up to 1.4 kHz is achieved by the prototype. The highest output force and the highest output speed of the prototype are 2.35 N and 3.75 mm s ⁻¹ , respectively.

This paper reports the mechanical design, waveform investigation and experimental validation of an flexible-structure-based inertia-drive linear motor. The flexible structure is designed and verified with finite element analysis to meet the bandwidth requirement for high-frequency actuation. In order to improve the output velocity, non-resonance low-harmonic driving waveform is implemented and evaluated. Experimental results show that the motor is capable of an output velocity of 2.41 mm/s with the waveform, compared to 0.73 mm/s with the classic saw-tooth waveform actuation. The improvement of the non-resonance low-harmonic waveform for the flexible-structure-based motor is confirmed.