Applied Mechanics and Materials Vols. 336-338

Abstract: Piezoelectric actuator has the characteristics of high displacement resolution, fast dynamic response, miniature size and etc. But its inherent hysteresis nonlinear affects its positioning accuracy. This paper analysis the hysteresis nonlinear characteristics of piezoelectric actuator, verifies the effect of hysteresis nonlinear on piezoelectric actuator, and compensate the hysteresis nonlinear characteristics by using the integrated control algorithm of feed-forward control and PI control, which can improve the control precision of the piezoelectric actuator.

Abstract: According with the problem that the error propagative characteristics of rotation inertial navigation system can not be quantitatively analyzed, a new error analyzing method is proposed. As the inertial navigation system can be equivalent to a low pass filter, the method converted the complex gyro drifts into signal which can be quantitatively analyzed after modulating through Fourier transform, thus the low frequency components of the error can be extracted. The relationship between navigation errors and gyro drifts is built by using the conventional error equations of strapdown inertial navigation system. The comparative analyses and computer simulation of conventional, uniaxial unidirectional and uniaxial reciprocating system prove the correctness and feasibility of this method. This method provides an effective reference for other same types of control system error analyses.

Abstract: This paper first introduces the trajectory mode of the each error source in detection the roundness error of NC machine tool. The error separation algorithm is derived according to the relationship between the various error sources and the machine tool motion trajectory. Based on the two testing link under different condition, comparing the test results under two testing conditions, the main error source of NC machine tools is further analyzed. According to the merits and demerits of the two kinds of detection methods, the different round error detection method can be chosen under different occasions.

Abstract: In order to restrain the accelerometer output error in rotational inertial navigation systems (INS), the imbalance torque of inertial measurement unit (IMU) and the magnetic field of motor were analyzed based on engineering application. The cause of imbalance torque and its influence mechanism were explained. Method taking plumbum mass to balance the IMU was proposed. The influence mechanism of motors magnetic field on accelerometer output was discussed. Method taking differential signal to communicate was devised. The compared results show the accelerometer output error is decreased effectively after taking these two methods. There is lower noise and no slow drift or hop count in accelerometer output.

Abstract: In order to improve the computational performance of the nonlinear observer for vehicle state and friction force estimation, two novel implementation schemes in Verilog Hardware Description Language (HDL) and System on Programmable Chip (SoPC) is proposed based on Field Programmable Gate Array (FPGA). Firstly, the parallelism analysis of the vehicle state and friction force estimation algorithm is provided. Then, the Verilog HDL and SoPC implementation schemes are presented respectively based on the analysis results. Finally, a testing platform is built to evaluate the functionality and the computational performance of the implementation schemes. The experimental results show that the proposed schemes all have high precision and computational efficiency for vehicle state and friction force estimation.

Abstract: Test and adjustment system of coordinator (T&ASC) is, virtual instrument technology based, developed. PXI measurement control platform, turntable system, target simulator and air source equipment are integrated in hardware design. Multithreading, IMAQ Vision module and DLL techniques are used in software programming. Technical difficulties as synchronous receiving of RS422 data with high speed, direct display of LVDS video image and integrated control of turntable are solved. The system achieves the integrated design of test, control and adjustment function, which can carry out overall performance tests for coordinator automatically, and execute system parameters calibrating and adjusting intelligently.

Abstract: For explore of prior unpredictable and unfriendly humans working environment, information return has a strong practical application. The article discusses how to remote control and command of the smart car operation, and how to transmit all kinds of information in smart car environment quickly and undistorted to commander. Researching method is the combination of 3G mobile communication network and smart car technology. The final design of the remote smart car product, the principle and the hardware design scheme are given in this paper.

Abstract: A finite element model of an ultra-precision grinding machine that can have high precision and high stiffness is constructed and structural analysis is done with equivalent stiffnesses of linear motion guides by after structural design and the deformation of the grinding machine is obtained. In order to reduce the deformation of the grinding machine that causes bad influence, structural complement is conducted by adding ribs at the lower part of the column. Also, the straightness of the grinding machine is improved by lifting that the base side of the column.

Abstract: A design approach of the temperature control of a novel microchip level PCR instrument based on SOPC technique is presented in this paper. The soft-core processor with RISC framework, NIOS II, which embedded in the FPGA (CyclonIII EP3C16F484C6) of Altera corp., is used as the key component to control the PWM controller achieving the temperature control of the micro-chamber stationary microchip level PCR instrument, to control the Avalon stream slave peripheral acquiring controller achieving the temperature signal detection by the flexible snake like copper wire temperature sensor, and to control the micro-pump and the micro-valve achieving the sample injection and sample outflow controlling. Simultaneously, the control temperature algorithm based on the Smith predictive and adaptive Fuzzy-PID is adapted in this system. The design of PCR microchip, the Smith predictive adaptive Fuzzy-PID temperature control algorithm, the hardware framework and the software design of control system are mainly introduced. And the simulation results testified the correctness of the design method and practicability. Keywords: Microchip level PCR instrument; Smith predictive and adaptive Fuzzy-PID controller; SOPC; The flexible snake like copper wire temperature sensor

Abstract: The Global Positioning System (GPS) has been approved for a limited number of applications in civil aviation because it is not highly available for meeting safety-of life levels of integrity, which require timely alert if the system is unreliable for navigation under the environment of Performance Based on Navigation (PBN). This paper presents an analysis about principle of an inertial navigation system (INS) and design an new mechanical architecture of INS in terms of increased availability of GPS for civil aviation. This new mechanical architecture has a good mechanical properties in mechanical engineering of civil aviation.