Yiyang Liu

The modeling and experiments of a PVDF mirco-force sensor

This paper aims at designing a kind of advanced micro-force sensor that can measure force in the range of sub- micro-Newton (muN). To accurately measure the micro interactive force (for example, adhesion, surface tension, friction, and assembly force) acting on micro devices during micromanipulation, the polyvinylidene fluoride (PVDF) is fabricated highly sensitive force sensors. This paper illustrates the modeling method of a PVDF sensor. The transformation between the micro interactive force and the output of the sensor is described. To calibrate the transformation, the model of the PVDF cantilever beam that shows the relationship between the interactive force and the deflection of the sensor probe tip is built first. Then, by given deflection, the interactive force can be calculated with the model. Finally, the transformation can be calibrated. Experiment results verify the effectiveness and accuracy of the transformation model, and the sub-muN sensitivity of the sensor. This micro force sensing technology will solve an important problem that restricts the development of micromanipulation and batch assembly of micro devices.

Overview of Micro-Force Sensing Methods

At present, reliable micro-force sensing is one of the most important research for micromanipulation and micro-assembly. Six kinds of methods to detect micro-force are described in this paper. Analysis of the basic principle and detection accuracy of each sensing method, and applications in micro-assembly and micromanipulation are briefly introduced. The purpose of this paper is to be useful to provide some references for scholars engaging in the micro-force sensing, which in turn promotes automatic processing level of micro-assembly and micromanipulation to reliably manufacture micro devices of high quality.

The design and development of a mirco-force sensing device

An advancing micro-force sensing device that can measure force in the range of sub-micro-Newton (muN) is designed and realized in this paper. To accurately measure the micro interactive force (For example, adhesion, surface tension, friction, and assembly force) between the tool and the object during micromanipulation, the polyvinylidene fluoride (PVDF) is used to fabricate a highly sensitive force sensing device. In this paper, the relationship model of the interactive force and the charge generated on the PVDF surface, the design of the signal processing method of PVDF output are illustrated. The transformation model between the micro interactive force and the signal of the sensing device is built. A new calibration method of the sensing device is presented. Experiment results verify the accuracy of the sensing devices transformation model, the effectiveness of the signal processing method. The results also show the sub-muN sensitivity of the sensing device. The micro-force sensing technology developed in this paper will promote the efficiency, and decrease the cost of micromanipulation and microassembly.

Design and Realization of Universal Radar Signal Processing Software

As parallel signal processing tasks are more and more widely used, a universal, efficient and flexible radar signal processing software is urgently needed in the field of radar signal processing. Traditional development of parallel signal processing needs a large number of specialized programs, and must couple with the hardware platform. Therefore, the cost of development and promotion is quite large. The universal radar signal processing software designed in this paper is an integrated development environment to achieve fully graphical, generalized, and modularized development. The software is able to automatically generate codes. This function replaces traditional developing method that needs designers write a large number of programs. The above function significantly shortens the developing cycle and improves the developing efficiency. Besides, the software is of powerful debugging features. Furthermore, the software has excellent generalization and expansibility for hardware platform.

DESIGN, MODELING, AND MICROMANIPULATION EXPERIMENTS OF A NOVEL 2-D MICRO FORCE SENSOR

Because of the micro/nano manipulations complexity, the accurate feedback information of the micro interactive force acting on micro devices is quite important and necessary for micro/nano manipulation, especially the 2-D micro interactive force feedback information. At present, there are no reliable and accurate 2-D micro force sensors applied in micro/nano manipulation. To solve the above problem, a novel 2-D micro force sensor that can reliably measure force in the range of submicro Newton (μN) is designed and developed in this paper. Based on the model of 1-D micro force sensor designed by us, the model of this 2-D sensor is set up. To verify the model of the 2-D sensor, micromanipulation experiments are designed and realized. Experiment results show the submicro Newton resolution, and verify the validity of the 2-D sensors model. The developed 2-D micro force sensor will contribute to promoting the complexity of micro/nano manipulation, and will facilitate to automate the micro/nano manipulation.

Research on PVDF micro-force sensor

At present, sub-micro-Newton (sub-μN) micro-force in micro-assembly and micro-manipulation is not able to be measured reliably. The piezoelectric micro-force sensors offer a lot of advantages for MEMS applications such as low power dissipation, high sensitivity, and easily integrated with piezoelectric micro-actuators. In spite of many advantages above, the research efforts are relatively limited compared to piezoresistive micro-force sensors. In this paper, Sensitive component is polyvinylidene fluoride (PVDF) and the research object is micro-force sensor based on PVDF film. Moreover, the model of micro-force and sensor’s output voltage is built up, signal processing circuit is designed, and a novel calibration method of micro-force sensor is designed to reliably measure force in the range of sub-μN. The experimental results show the PVDF sensor is designed in this paper with sub-μN resolution.

Research on Millimeter-Wave Radar Based Automotive Lateral Anti-Collision Warning System

According to the reasons and features of car accidents happening in vehicles’ side areas, this paper designed and developed a kind of automotive lateral anti-collision warning system by frequency modulation continuous wave, based on the research on 24GHz linear frequency modulation continuous wave radar-probing system. The system designed in this paper will forecast the potential danger to drivers and avoid the accidents. The hardware structures, algorithm, program flows and working patterns of the warning system were introduced. Furthermore, pointing to the problem of false alarms, a kind of filtering method was presented creatively. This method improved the reliability of the warning system and the accuracy of the forecast. It filtered the disturbance coming from the side of the vehicles, and solved the difficult problem that prevented the millimeter-wave radar from being applied in automotive lateral anti-collision warning system. Finally, the experiment was designed and carried out. The result verified the rationality of the solution and the practicality of the system’s function.

Research on Motion Compensation for Airborne SAR Interferometry System

Deviation from definitive flight path of a plane fixed a synthetic aperture radar (SAR) leads to inaccurate and defocused radar images, which has serious effect on the SAR interferometry (InSAR) processing. Therefore, the precise motion compensation (MOCO) for the airborne SAR interferometric data is the key to obtain high quality digital elevation model (DEM).The position and orientation system (POS)-based residual motion error compensation method is designed. Considering the precision of POS, there will be residual motion error after the POS-based MOCO, which have serious effect on the interferometric phase, especially the residual baseline errors. To solve the above problem, this paper proposed an enhanced multi-squint processing based model to estimate the residual baseline errors. This method can decrease the influence of data decorrelation and baseline error varying with range, and dramatically improve the measuring accuracy of InSAR.

INFINITE DIMENSION MODELING OF A NOVEL MICRO FORCE SENSOR AND THE APPLICATION IN MICROMANIPULATION

To accurately measure the micro interactive force (For example, adhesion, surface tension, friction, and assembly force) acting on micro devices during micro/nano manipulation, a novel micro force sensor that can reliably measure force in the range of sub-micro-Newton (μN) is designed and developed in this paper. During the application of this micro force sensor in micro/nano manipulation, the accuracy of this sensor’s model is quite important to the force control of the system. Therefore, the accurate infinite dimension model of the micro force sensor and micro manipulator is built up. Based on the infinite dimension model, the impedance control system is designed. To verify the infinite dimension model and the control system, micromanipulation experiments are designed and realized. Experiment results verify the accuracy of the infinite dimension model of the sensor, and show the efficiency of the impedance control system. The developed micro force sensor and the infinite dimension modeling provide a feasible and versatile solution in micro force sensing and feedback force control for micro/nano manipulation, and will promote the technology of automating the micro/nano manipulation.