Review of long range high resonant frequency compliant nanopositioning technology

With the rapid advancement of scientific research and industrial manufacturing, the demand for motion control with nanometer-scale precision has grown significantly. Compliant nanopositioning technologies, which enable frictionless, backlash-free, and highly repeatable motion through elastic deformation, have become a fundamental enabler for high-end equipment such as atomic force microscopy, semiconductor manufacturing systems, and ultra-precision machine tools. In these systems, two key performance indicators, i.e., positioning range and resonant frequency, largely determine the achievable working space and dynamic response speed, respectively. However, these two parameters are intrinsically coupled and often mutually restrictive: increasing the positioning range typically leads to reduced structural stiffness and, consequently, a lower resonant frequency, while enhancing resonant frequency generally limits the achievable displacement. This fundamental trade-off poses a critical bottleneck in the design and optimization of high-performance nanopositioning systems. Therefore, the development of compliant nanopositioning technologies that simultaneously achieve large travel range and high resonant frequency is of great scientific significance and practical value for advancing next-generation precision scientific and engineering systems.

This paper focused on compliant nanopositioning technologies with large travel range and high resonant frequency and systematically analyzed the intrinsic mechanisms underlying the trade-off between positioning range and resonant frequency. From the perspective of system configuration and performance evaluation, the relationship among structural stiffness, actuation capability, displacement amplification, and dynamic characteristics was first analyzed, revealing the physical origins of the range-frequency contradiction. Building upon this understanding, recent research efforts aimed at overcoming this limitation are comprehensively reviewed. In terms of actuation strategies, various approaches based on piezoelectric actuators, voice coil motors, and normal-stressed electromagnetic actuators were discussed, highlighting their respective advantages and limitations in achieving both large displacement and high bandwidth. In particular, attention was given to innovative structural designs, such as compliant amplification mechanisms, parallel and serial kinematic configurations, and multi-degree-of-freedom architectures.

In addition to structural design, control-related challenges were also introduced. The control issues inherent in compliant mechanisms and actuators, such as lightly-damped resonances, hysteresis nonlinearities, and cross-coupling effects, become more pronounced when attempting to operate across large ranges and high frequencies. To address these issues, a variety of advanced control strategies have been developed, including feedforward compensation, model-based control, robust control, and learning-based approaches. These methods aim to enhance positioning accuracy, improve dynamic response, and suppress unwanted vibrations. Through a critical review of representative studies from both domestic and international researchers, the current state of the art was summarized, and the effectiveness of different technical routes in mitigating the range-frequency trade-off was comparatively analyzed.

In summary, the inherent trade-off between positioning range and resonant frequency remains a fundamental challenge in the development of compliant nanopositioning systems. Although substantial efforts have been made from the perspectives of structural design, actuation strategies, and control methods, a universally effective solution that simultaneously achieves a large travel range and a high resonant frequency has yet to be established. Existing studies have demonstrated that different technical approaches can partially alleviate this contradiction under specific conditions, but their applicability is often limited by system complexity, performance trade-offs, or practical constraints.

Based on the current research progress, future developments in this field are expected to focus on more systematic and integrated design methodologies in which mechanical structures, actuation mechanisms, and control strategies are jointly optimized to achieve improved overall performance. Meanwhile, continued exploration of novel configurations and actuation principles may further expand the achievable design space.

Overall, by summarizing the intrinsic mechanisms of the range-frequency trade-off and reviewing representative research efforts, this work provides a clear picture of the current state of compliant nanopositioning technologies and identifies their development trends. The insights presented are expected to serve as useful references for the design and advancement of high-end equipment and precision instruments.