Recently, Research, a Science Partner Journal, published the latest advances in the field of piezoelectric-electromagnetic dual-mechanism linear nano-actuation, entitled "A Piezoelectric and Electromagnetic Dual Mechanism Multimodal Linear Actuator for Generating Macro- and Nanomotion". (https://spj.sciencemag.org/research/2019/8232097/).
Ultra-precision positioning technology is one of the core key technologies in precision manufacturing, precision measurement and precision actuation. It plays an extremely important role in modern cutting-edge industrial production and scientific research, and it influences the development of high technologies in various fields. Developed countries such as Europe and the United States lead in microelectronics technology and high-tech leading position due to their ultra-precision positioning and testing technology development. Especially in the field of semiconductor chip processing, photolithography machine acts as the most important core chip processing equipment in semiconductor processing, and most of the moving parts and optical components require ultra-precision nano-actuation.
At present, the most advanced chip line width of lithography processing can reach 7 nm, but the gap of current technology level between China and these countries is huge, and it becomes a limit ingress and limits the development of the semiconductor industry. How to achieve high motion speed and high velocity over long working distance, but also with nano-resolution, has become an urgent problem for precision mechanical motion system, precision servo actuators and motors. Common precision positioning linear motors include piezoelectric ultrasonic motors, piezoelectric step motors, and electromagnetic motors, whereas they have their limitations. Piezoelectric ultrasonic motor has high motion speed and positioning resolution, but its high-frequency friction loss limits its precise application for long-term continuous work; and the piezoelectric step motor has the highest motion resolution, but the movement speed is slow which is not suitable for high-speed, large-stroke precision motion and positioning. The traditional electromagnetic linear motor also has the following issues. (1) The response speed is slow; (2) there is no self-locking when power off; (3) the displacement resolution is relatively low, and it is difficult to achieve the nano-scale precision motion and control.
Figure 1. Schematic working principle diagram for Dual Mechanism Multimodal Linear Linear Actuator.
In order to solve these problems, Professor Shuxiang Dong’s team in the Department of Materials Science and Engineering in the College of Engineering designed and developed a dual mechanism nano linear motion platform (Dual Mechanism Multimodal Linear Linear Actuator). The invention combines the electromagnetic and piezoelectric dual mechanism by the design of co-slider and co-stator. It uses the electromagnetic mechanism to produce macro-fast motion, piezoelectric step motion to produce micro-low-speed motion, piezoelectric servo mechanism for nano-motion positioning. It is able to achieve macro-micro-nano scale motion precision positioning at the same time. This new dual-mechanism motion system design is expected to effectively overcome the traditional various single mechanism motor problems, especially for the dilemma of long range rapid movement and nano-positioning accuracy. Now it has been applying for Chinese invention patent. The test results show that the maximum operating speed is 51.2 mm/s in electromagnetic macro-motion, the speed of the piezoelectric step micro-motion is 0 to 135 μm/s, and the minimum displacement resolution can reach 2 nm in open-loop control during piezoelectric servo movement. The test results are shown in Figure 2. “Compared with the traditional single-mechanism electromagnetic motion platform or piezoelectric motor, it possesses outstanding advantages in motion displacement resolution, motion speed, etc. The proposed design of dual-mechanism nano-linear actuation provides a new path for the next generation of ultra-precision motion platform,” the group said.
Figure 2. Test results of Dual Mechanism Multimodal Linear Linear Actuator: (a) electromagnetic macro-motion with maximum operating speed of 51.2 mm/s; (b) piezoelectric step micro-motion; (c) piezoelectric servo nanoscale motion with the minimum displacement resolution of 2 nm.
Dr. Xiangyu Gao is the first author of this work. He obtained his Ph.D. degree from College of Engineering, Peking University in 2019 and now he works as a lecturer in Xi’an Jiaotong University. Professor Shuxiang Dong is the only corresponding author of the paper. The research was supported by the National Natural Science Foundation of China (51772005, 51132001), China Aerospace Academy of Systems Science and Engineering, Beijing Key Laboratory for Magnetoeletric Materials and Devices.