On December 4, 2022, the return capsule of the Shenzhou-14 manned spaceship successfully landed. The Shenzhou-14 manned space mission achieved a complete success, demonstrating China’s strong strength in the field of aerospace science and technology. Among numerous aerospace electrical equipment, ultrasonic motors have been widely used because they are not affected by space electromagnetic radiation and can maintain excellent mechanical properties in environments with drastic temperature differences. Nanjing Innovation Investment Group has invited Zhao Chunsheng, Academician of the Chinese Academy of Sciences and Professor of Nanjing University of Aeronautics and Astronautics, to interpret the technology and development direction of this micro-special motor based on his long-term professional experience and expert perspective.
Zhao Chunsheng is a renowned mechanical engineering expert, Academician of the Chinese Academy of Sciences, Professor and Doctoral Supervisor of Nanjing University of Aeronautics and Astronautics. Academician Zhao Chunsheng is the founder of China’s ultrasonic motor industry and one of the earliest and most comprehensive researchers in the field of ultrasonic motor technology.
He has long been engaged in the research on vibration engineering theory and its application, and has proposed systematic theories and design methods in the aspects of ultrasonic motor motion mechanism, electromechanical coupling model, structural parameter optimization design, drive and control technology. He has obtained more than 60 authorized national invention patents, published over 400 academic papers, and won 2 Second Prizes of National Technological Invention and 1 Third Prize of National Science and Technology Progress. He has also been awarded honors such as the "Ho Leung Ho Lee Foundation Science and Technology Progress Award", the international "Ultrasonic Motor Lifetime Achievement Award", the "Outstanding Contribution Award in Ultrasonic Motor Technology", "National Advanced Worker" and "Most Beautiful Scientific and Technological Worker".
Nanjing Innovation Investment Group
Academician Zhao, you have been researching ultrasonic motors for 30 years, achieving multiple "zero-breakthroughs" and breaking foreign technological monopolies in this field. Why did you choose to engage in research in this field in the first place?
Zhao Chunsheng
In 1993, when I was a visiting scholar at the Massachusetts Institute of Technology (MIT) in the United States, I accidentally attended a lecture on "the development and application of ultrasonic motors". The speaker mentioned that NASA and MIT would jointly develop ultrasonic motors for Mars rovers. It was the first time I heard the new term "ultrasonic motor", and I felt that it would definitely be useful in China’s spacecraft. So I decided to shift my research direction and conduct research on ultrasonic motors independently developed by Chinese people. In 1994, I returned to China alone with a large amount of materials and components, which filled five large boxes. There were so many materials that I had to ship them by sea from Boston, and they finally arrived in Nanjing via Hong Kong. After returning to China, I borrowed funds from Nanjing University of Aeronautics and Astronautics to buy a computer and a printer, and then led my team to start researching ultrasonic motors. In less than a year, we developed China’s first practical traveling-wave ultrasonic motor that could operate normally.
Nanjing Innovation Investment Group
What are the characteristics of ultrasonic motors?
Zhao Chunsheng
Different from traditional motors, ultrasonic motors have no windings or magnetic poles. They utilize the inverse piezoelectric effect of piezoelectric ceramics and ultrasonic vibration to convert the micro-deformation of materials into the macro-motion of the rotor through mechanical resonance amplification and friction coupling. Ultrasonic motors are not affected by electromagnetic interference, can be applied in scenarios requiring high torque at ultra-low speeds, and have extremely high positioning accuracy. In addition, ultrasonic motors also have the advantages of light weight, small size and unlimited stroke.
Nanjing Innovation Investment Group
In which fields are ultrasonic motors applied?
Zhao Chunsheng
Ultrasonic motors have broad application prospects in fields such as automotive electrical appliances, precision instruments and meters, industrial control systems, and aerospace. The ultrasonic motors developed by our team have evolved from the initial traveling-wave rotary type to a series of products, including 3 rotary ultrasonic motor series and 1 linear ultrasonic motor series. The rotary types include TRUM (circular plate type), BTRUM (circular rod type), CTRUM (hollow type), etc. Their diameters range from a maximum of 120 mm to a minimum of only 2 mm. Among them, the performance indicators of the TRUM series ultrasonic motors have reached the international advanced level, and some products have been applied in nuclear magnetic resonance injectors, eggshell strength detectors, three-joint manipulators, robot vacuum cleaners, wing flutter test systems, safety control systems, tracking and monitoring systems, attitude adjustment of laser system frames, cell puncture, as well as the "Chang’e-3", "Chang’e-4" and "Micius" scientific satellites. Some products are also being applied in weaponry, artificial satellites, "Chang’e-5" and inertial nuclear fusion ignition projects.
Nanjing Innovation Investment Group
How are ultrasonic motors applied in the "Chang’e" series satellites?
Zhao Chunsheng
In the "Chang’e-3" project, the Aerospace Research Institute intended to use domestically produced ultrasonic motors for the drive and control of the spectrometer. I thought it was a rare opportunity and immediately decided to take on this task! At that time, we encountered many problems in materials and processes, especially since the motor had to adapt to the extreme environment on the moon. To develop this type of ultrasonic motor, we conducted thousands of tests, including more than 300 tests simulating the lunar working environment, such as complex extreme environment tests and radiation tests. Finally, our motor was installed on the lunar rover, specifically for driving and controlling the spectrometer. It determined when the "shutter" of the spectrometer would open to allow light in and when to close to prevent lunar dust from entering.
Nanjing Innovation Investment Group
How should the industrialization of ultrasonic motor technology and products be realized?
Zhao Chunsheng
Compared with the title of academician, I value the industrialization of scientific research achievements more. Relying on the Precision Drive Research Institute of Nanjing University of Aeronautics and Astronautics, we established the "National and Local Joint Engineering Laboratory for Ultrasonic Motors". This joint engineering laboratory is the first and only national-level ultrasonic motor technology incubator in China. It will focus on building an ultrasonic motor pilot production line and a national-level ultrasonic motor testing center, and develop into an integration and innovation base, an achievement promotion base, an engineering testing and detection standardization base, and a talent training base for ultrasonic motors and their application systems. The establishment of the laboratory has promoted the application of ultrasonic motor technology achievements and driven the development of the industry. The laboratory has also incubated an intelligent manufacturing equipment company (referring to Nanjing Silai Robot Co., Ltd.) and promoted the application of piezoelectric precision drive technology in the field of intelligent manufacturing.
Nanjing Innovation Investment Group
What achievements have been made in the industrialization of ultrasonic motors?
Zhao Chunsheng
We have overcome key technologies such as flexible structural design of special ultrasonic motors, high-reliability storage/service performance, and high-precision speed and position control under special working conditions, and established China’s independent and controllable ultrasonic motor technology and intellectual property rights. In addition, we have established Hangda Super Control Co., Ltd. to transform and market ultrasonic motor technology in the field of high-end equipment. Apart from applications in lunar exploration projects and space laser communication, we have also applied ultrasonic motors to high-end medical equipment by leveraging their characteristics of low-speed and high-torque, high-precision control, and no electromagnetic field. For example, in nuclear magnetic resonance equipment, ultrasonic motors have no electromagnetic field, so they have become the executive motors in nuclear magnetic resonance medical equipment. The ultrasonic motors developed by us can replace the products of Shinsei Corporation of Japan and have reached the international first-class level. In addition, Silai Co., Ltd. is now a "Gazelle Enterprise" (a high-growth technology enterprise) and a national-level high-tech enterprise, and has also received investment from Nanjing Industrial Fund. Silai Co., Ltd. has built China’s first intelligent assembly and testing production line for ultrasonic motors for the laboratory. The production line uses independently developed technologies such as precision drive, machine vision and digital twin. We aim to produce thousands of ultrasonic motors in Nanjing and enter and occupy the international market.
Nanjing Innovation Investment Group
The industrialization of ultrasonic motors is extremely difficult. What experience can Academician Zhao share with young people who are starting their own businesses?
Zhao Chunsheng
We did encounter some difficulties on the road of ultrasonic motor industrialization. What should we do then? Should we stop here or continue moving forward? There is no doubt that we must keep going. In 2016, within half a year, I negotiated cooperation with more than 30 units in a row, and I visited each of them in person. At the same time, I took every opportunity to promote ultrasonic motors. I once reported in detail to Secretary Li Qiang (then Secretary of the Jiangsu Provincial Party Committee) on the application of ultrasonic motors in scientific research, production and national defense. Besides persistence, another important point is integrity. Whether in life, work or academic research, if we lack integrity, we will eventually harm others, ourselves and society. I have personally experienced incidents where students or partners were dishonest. If dishonesty becomes a common social problem, it will seriously hinder social and economic development.
Nanjing Innovation Investment Group
Academician Zhao, you were once diagnosed with lung cancer and gastric cancer, and underwent two cancer resection surgeries and six rounds of chemotherapy. Now you are in good health, and even at the age of 85, you are still guiding scientific research work on the front line.
Zhao Chunsheng
On December 2, 2000, I was diagnosed with lung cancer. At that time, the ultrasonic motor had just been successfully trial-produced, and there were still many things to be done next. My main concern was: if something unexpected happened to me, who would take charge of the newly established Ultrasonic Motor Research Center? I couldn’t let the research team and research center, which we had worked so hard to build, collapse like this. As long as there was a glimmer of hope for survival, I would not give up. At that time, I quickly made a second decision: to cooperate with the doctor for treatment as soon as possible, and the surgery was scheduled for December 5. During a re-examination four months after the surgery, I was diagnosed with gastric cancer. Later, I underwent a series of surgeries and treatments, during which the tumor and two-thirds of my stomach were removed. My daughter asked me whether I wanted to save my life or continue researching ultrasonic motors. I said I wanted both.
Source: Zhao Chunsheng, Bai Yang from the Second Investment Department
Reviewer: Xue Yao
Publisher: You Yi
