Views: 0 Author: Site Editor Publish Time: 2021-12-20 Origin: Site
Piezoelectric materials have an excellent ability to convert mechanical force into electrical charge and vice versa. Piezoelectric ceramics such as lead zirconate titanate, lead magnesium niobate-lead titanate, etc. have been widely used in sensors, actuators, transducers and energy harvesters. However, the piezoceramics material itself is brittle. For traditional ceramic materials, mechanical flexibility and piezoelectricity are two contradictory properties. Improving one performance usually damages the other. For example, lead zirconate titanate-based ceramics have higher piezoelectric properties, but due to their inherent brittleness, lead zirconate titanate-based ceramics are not suitable for direct integration into flexible electronic devices. In order to broaden the application of piezoelectric materials in flexible sensing and other fields, it is necessary to develop flexible piezoelectric ceramic composite materials that have both mechanical flexibility and response to environmental mechanical vibrations or external stimuli.
or heterojunction structure, the piezoelectric voltage coefficient of the polarized piezoelectric composite material has also been significantly improved, which can reach 400×10-3 V m N -1. Further research found that the polarized 3D printed piezoelectric composite material has high sensitivity to slight finger taps, and has a large voltage response to the impact of free falling objects; through electromechanical coupling, it can be effectively The input mechanical energy is converted into electrical energy, and 20 commercial red LED lights can be lighted without using any charge storage unit. The results of this research are expected to have important application potential in future flexible wearable electronic devices, robotic flexible sensing and biosignal recognition, as well as mechanical energy recovery.
Ultrasonic motor that shows great power in medical equipment
Medical micro-machine power source-USM
The main problem of the current research in the field of biomedical micromechanical systems is to find a small, long-term power source, and to pack the medicine into a capsule or package, and perform verification and monitoring. Drug delivery devices and systems manufactured by micro-manufacturing technology currently have many advanced technologies, especially in the delivery of drugs through micro-probes and the release of drugs injected into the human body.
The jet micro system for drug delivery includes micro ultrasonic motors or micro piezoelectric pumps, electrophoresis plasters and smart pills. Ultrasonic motors are used as the power of micro-medical devices to guide the traction medical devices into the human body or deliver drugs to the human body.
USM shows great power in medical equipment
In the process of gene transplantation and artificial insemination, inserting a tiny pipette into the cytoplasm is an indispensable operation. When piezoceramics transducers are operating with a traditional hydraulic actuator, due to the elasticity of the cell membrane, the entire cell of will be greatly deformed, and this excessive deformation will cause damage to the cell nucleus. The laboratory has developed a set of cell manipulation micro-processing system, which uses an impact linear ultrasonic motor to achieve a smooth movement without major deformation of the cell membrane.
Multi-degree-of-freedom ultrasonic motors are also used in surgical operations. The developed cylindrical multi-degree-of-freedom ultrasonic motor is applied to surgical forceps, and a neural network method is proposed to precisely control the rotation angle of the forceps.
In the capsule endoscope, how to control the rotation and focus of the lens is a difficult problem. The use of a new piezoelectric tube-type ultrasonic micro-motor provides a solution to this problem. The key improvement lies in the use of a hollow piezoelectric ceramic tube ultrasonic motor and a prism with a focusing surface. The optical fiber is inserted into the hollow ultrasonic motor, the light is collimated by the self-focusing lens, and then reflected by the prism, until it exits, it is focused by an aspheric surface. When the motor is working, it can drive the self-focusing lens and the prism to rotate at the same time, so as to realize the circular scanning. This can significantly shorten the working distance of the optical system and improve the lateral resolution. At the same time, because the optical fiber and the motor are on the same side, the length of the probe is shortened, and problems such as the motor wire blocking the imaging are avoided.
USM is very suitable for NMR
Because the ultrasonic motor does not generate a magnetic field by itself, and is not subject to magnetic field interference, it is very practical for nuclear magnetic resonance. When a patient undergoes an MRI examination, he needs to inject medicinal solution, and the injection requires a constant speed. The best way is to drive the motor at a constant speed, but the traditional electromagnetic motor itself generates a magnetic field, which interferes with the imaging. The use of ultrasonic motors will not.