Nominal Model-Based Sliding Mode Control with Backstepping for 3-Axis Flight Table

Based on nominal model, a novel global sliding mode controller （GSMC） with a new control scheme is proposed for a practical uncertain servo system. This control scheme consists of two combined controllers, One is the global sliding mode controller for practical plant, the other is the integral backstepping controller for nominal model. Modeling error between practical plant and nominal model is used to design GSMC. The steady-state control accuracy can be guaranteed by the integral backstepping control law, and the global robustness can be obtained by GSMC. The stability of the proposed controller is proved according to the Lyapunov approach. The simulation results both of sine signal and step signal tracking for 3-axis flight table are investigated to show good position tracking performance and high robustness with respect to large and parameter changes over all the response time.

Stiffness of Postural Alignment System Based on 3-Axis Actuators for Large Aircraft Components

Aircraft digital flexible assembly fixture and technologies are widely used in developed countries, while the traditional jig-based assembly mode is still used in China. The application study of aircraft digital flexible assembly system is just beginning in our country recently. To meet the requirements of automated posture alignment and join in digital assembly system for large aircraft components, a novel fitting fixture called 3-axis actuator is developed. On the basis of the actuators, three kinds of posture alignment system for large aircraft components are proposed, including the non-redundant system, the redundant actuating system, and the redundant leg system, and their constitutions and properties are introduced. Through deriving the feeding transmission stiffness model of single actuator and analyzing the inverse kinematics of these systems, the relationship between the external force and the changes of position and orientation of large aircraft component is obtained, and then the postural alignment stiffness models are established. With the method mentioned above, the postural alignment stiffness of three systems is computed by using the algebraic formulate, and the results show that redundant properties can increase system＇s postural alignment stiffness. As an example, a optimized layout of the assembly system for a given model of aircraft is developed, the results of application show that the layout has many advantages, such as high accuracy, stiffness, stability, reliability, efficiency and flexible, which can satisfy the requirement of aircraft digital assembly system well. The proposed study of postural alignment stiffness for different systems can supply the theoretic support for the optimization layout design of aircraft digital assembly system, and contribute to evaluate the system working performance of systems.

QFT Robust Control Design for 3-Axis Flight Table Servo System with Large Friction

The 3-axis flight table is an important device and a typical high performanceposition and speed servo system used in the hardware-in-the-loop simulation of flight controlsystem. Friction force and uncertainty are the main characteristics in the 3-axis flight table servosystem. Based on the description of dynamic and static model of a nonlinear Stribeck frictionmodel, and taking account of the practical uncertainties of 3-axis flight table servo system, theQFT controller is designed. Simulation and realtime results are presented.

Dissymmetrical 3×3 Coupled Optical Accelerometer

Without adding feedback to modulate light path system, the dissymmetrical 3×3 coupled optical accelerometer reduces the complexity of the design of light path system. Experiments prove that it can attain good demodulation effects. As carrier is not needed in this system, the frequency range of input signal is diminished so as to decrease the sampling frequency of accelerometer. This makes for the system on programmable chip(SOPC) design of digital demodulating system. The upper limit of accelerometer working frequency can reach 3 500 Hz. But affected by the inherent frequency of sensitive components, its working frequency is 10 Hz^1 000 Hz, and the sensitivity is 8.718 0 V/(m·s-2). This accelerometer can detect the dynamic range of acceleration signal real-timely, steadily and accurately, solving the dissymmetrical problem of light path caused by circumstances and the complexity of process.

Fiber Optic 3-D Space Piezoelectric Accelerometer and its Antinoise Technology

The mechanical structure of piezoelectric accelerometer is designed, and the operation equations on X , Y , and Z axes are deduced. The test results of 3 D frequency response are given. Noise disturbances are effectively eliminated by using fiber optic transmission and synchronous detection.

Hybrid 3D printed three-axis force sensor aided by machine learning decoupling

Identification of magnitude and orientation for spatially applied loading is highly desired in the fields of not only the machinery components but also human-machine interaction.Despite the fact that the 3-axis force sensor with different structures has been proposed to measure the spatial force,there are still some common limitations including the multi-step manufacturing-assembly processes and complicated testing of decoupling calibration.Here,we propose a rapid fabrication strategy with low-cost to achieve high-precision 3-axis force sensors.The sensor is designed to compose of structural Maltese cross base and sensing units.It is directly fabricated within one step by a hybrid 3D printing technology combining deposition modeling(FDM)with direct-ink-writing(DIW).In particular,a machine learning(ML)model is used to convert the strain signal to the force components.Instead of a mount of calibration tests,this ML model is trained by sufficient simulation data based on programmed batch finite element modeling.This sensor is capable of continuously identifying a spatial force with varying magnitude and orientation,which successfully quantify the applied force of traditional Chinese medicine physiotherapy including Gua Sha and massage.This work provides insight for design and rapid fabrication of multi-axis force sensors,as well as potential applications.

Design of Three-component Photoelastic Waveguide Accelerometer

In order to realize a high accuracy seismic exploration in the high electro-magnetic field and to improve oil producibility and recovery efficiency,a three-component photoelastic waveguide accelerometer is designed. Based on the photoelastic effect,the Mach-Zehnder integrated optical interferometer is designed to measure the three-orthogonal components of acceleration and the combined three-component simple harmonic vibrator is designed to reduce the cross-talk among the acceleration components. According to the variation of LiNbO3 waveguide phase under the action of the applied acceleration,the cross-axise sensitivity and transverse sensitivity ratio(TSR) were analysed. The results reveal that the accelerometer has wide band and good linearity. It can satisfy the sensor requirements of high accuracy seismic exploration. The main design parameters of the geophone system are:phase sensitivity:1.86×10-4 Rad·m-1·s-2,natural frequency:3 500 Hz,and the transverse sensitivity ratio:0.11%.

手推式电子叉车秤倾角与称重误差补偿算法研究

针对电子叉车秤在使用过程中出现的车体倾斜导致称重误差精度下降等问题,提出了一种有效的称重误差补偿算法。首先,分析电子叉车秤倾斜角度对称重性能的影响,搭建一个多方向可变角度倾斜的实验平台,以模拟叉车秤的倾斜状态并获取精确的称重数据。其次,根据所获得的数据与称重误差补偿原理,建立倾斜状态下电子叉车秤的称重误差补偿算法模型,并运用最小二乘法及多层感知机非线性回归方法识别模型参数。最后,本文对具有1500 kg量程和0.02 kg感量的电子叉车秤进行了倾斜测试实验,结果表明,在地面倾角不超过1.5°的范围内,在任意倾斜方向仪器最大允许误差MPE<0.75 kg,具有3000分度数的精度。

Application of Novel Rotation Angular Model for 3D Mouse System Based on MEMS Accelerometers

A new scheme is proposed to model 3D angular motion of a revolving regular object with miniature, low-cost micro electro mechanical systems(MEMS) accelerometers(instead of gyroscope),which is employed in 3D mouse system.To sense 3D angular motion,the static property of MEMS accelerometer,sensitive to gravity acceleration,is exploited.With the three outputs of configured accelerometers,the proposed model is implemented to get the rotary motion of the rigid object.In order to validate the effectiveness of the proposed model,an input device is developed with the configuration of the scheme.Experimental results show that a simulated 3D cube can accurately track the rotation of the input device.The result indicates the feasibility and effectiveness of the proposed model in the 3D mouse system.

电子秤倾角自动检测与称量误差补偿方法研究

针对传统电子秤水平调节繁琐,存在倾角时称重准确度低等不足,设计了一种具有倾角自动检测与称量误差补偿功能的高精度电子秤。分析了秤台倾角对电子秤称量性能的影响,介绍了基于三轴加速度传感器ADXL345的倾角检测和称量误差补偿原理,提出并建立了电子秤倾角自动补偿模型,给出了基于微处理器ADuC7060的倾角测量系统的软、硬件设计与实现方案。对量程为1 000 g、感量为0.01 g的电子秤倾角补偿后进行的测试结果表明,在倾角小于1°时,仪器的最大允许误差MPE<0.05 g;当倾角小于15°时,最大允许误差MPE<0.2 g。

基于三轴加速度传感器的老年人摔倒检测系统

为解决老年人摔倒检测中的检测精度和检测设备功耗高的难题,设计了基于三轴加速度传感器的老年人摔倒检测系统。采用MEMS三轴加速度传感器和低功耗单片机完成人体三轴加速度数据的采集和处理,以满足低功耗要求;并建立基于三轴加速度信息的摔倒检测阈值点判断算法,并对关键参数进行确定,以提高检测算法精度。通过仿真老年人日常行为动作和多种摔倒行为,获取到全面有效实验数据,采用阈值点摔倒检测算法进行验证。摔倒准确率为93.96%,说明系统可以有效地对老年人摔倒行为作出检测,实现低功耗长时间工作。

内嵌加速度计的智能轮胎纵/垂向力估计算法

本文中提出了一种基于胎内嵌入加速度计的智能轮胎方案和纵向与垂向轮胎力估计算法。首先设计了基于三轴加速度计的智能轮胎系统;接着搭建了实车测试平台并在典型工况下进行了实车试验;基于实车试验数据,提取了智能轮胎加速度信号的典型特征,结合轮速等影响因素,提出了基于神经网络的轮胎纵向力和垂向力估计算法。结果表明,所提出的算法可对轮胎力进行准确的估计,从而为车辆的稳定性控制系统提供有用信息。

三轴加速度计GFSINS安装误差标定与补偿方法

针对由四个三轴加速度计构成的无陀螺捷联惯导系统加速度计的安装误差,根据空间矢量与坐标系关系,提出一种基于矢量模值不变性的位置误差标定方法和一种坐标系旋转变换矩阵的敏感方位误差标定方法,采用同一组转台试验数据先标定出位置误差再在位置误差标定基础上标定方位误差。同时,提出在误差补偿过程中,先补偿敏感方位误差再补偿位置误差的补偿方法,且给出了具体补偿算法。最后,通过仿真验证了标定和补偿方法的可行性。

基于三轴加速度传感器和电子罗盘的人体摔倒监测系统

设计了一种具有远程监控功能的人体摔倒监测系统,为实现系统的小体积和低功耗,系统硬件主要由MS]P430F149单片机、三轴加速度传感器、电子罗盘和无线通信模块组成,由MMA8453Q采集人体运动过程中的三轴加速度数据、CPS320T模块采集人体运动状态参数、无线模块nRF24L01实现系统与工作站间的数据通信。分析了系统的主要硬件模块的接口电路设计方法,并给出了基于硬件的摔倒监测算法。实验结果表明,本系统摔倒监测准确率达98.8%,功耗低,具有很强的实用性。

基于ARM的三维汽车振动加速度测量方法研究

提出了一种基于ARM和加速度传感器的三维汽车振动加速度测量方法。在现有研究基础上,设计出能测量三维加速度的处理电路,利用32位高性能ARM处理器LPC2129的捕获通道和ADC通道实现对三维加速度信号的同时测量,并给出了测量的程序流程。实现结果表明:该测量方法简化了系统,同时提高了系统的测量精度和实时性。

基于厚膜技术E型三维加速度传感器的设计

提出采用厚膜技术设计一种一体化三维加速度传感器 ,其采用E型结构和特殊的组桥方式实现对三维加速度信息的检测。介绍了传感器的结构 ,并详细讨论了传感器工作原理和维间耦合问题。由于E型结构的对称性 ,使得所设计的三维加速度传感器在低量程、高灵敏度应用场合中具有良好的特性。

三轴电容式微加速度计接口ASIC设计

基于CSMC0.5um CMOS工艺,给出了一款3轴电容式微加速度计接口ASIC的详细设计方案。利用时分复用技术实现了使用同一电路模块同时检测3个轴向的加速度信号,利用相关双倍采样技术提高了电容电压转换的分辨率,利用Sigma_Delta调制技术对电路噪声进行有效整形。仿真得到系统的分辨率为0.91 a F/Hz1/2,3个轴向的噪声密度分别为43.60μg/Hz1/2、43.60μg/Hz1/2和45.70μg/Hz1/2,3个轴向输出数字脉冲信号占空比的非线性度分别为1.38%、0.91%和1.79%。

基于MEMS传感器惯性测量单元设计与实现

随着微电子机械系统(MEMS)技术的发展,出现了大量高性价比MEMS传感器,被广泛应用于多个领域。然而惯性测量单元通常包括多个传感器,如三轴MEMS加速度、角速度和磁力传感器,这样要求有多个数据通道输出,给原型系统设计和开发带来不便。基于此,文中设计了一种惯性传感板,集成MEMS三轴加速度传感器、三轴角速度传感器和三轴磁力传感器,通过单个UART串口可以读取9通道数据。经过试验验证,该惯性传感单元能够满足一般原型系统的快速设计和开发。

基于三轴加速度计的倾斜角传感器的研究与设计

倾斜角度是生活或工业中需要测量的一个重要物理量,对于空间物体姿态的测量,传统的一轴、两轴倾斜角传感器在摆幅和方位上不能兼顾。在此对全固态电容式微加速度传感器进行研究,通过进行零刻度偏移补偿、横轴传感补偿、数据融合等方法提高测量精度。采用三轴加速度计设计了一个全摆幅、全方位、高精度的智能化三轴倾斜角传感器。

一种三维加速度计弹性体的分析与设计

介绍了一种可用于振动测量的三维加速度计弹性体结构,其采用3个相互垂直的双平行应变梁组合的形式,每个平行梁敏感一个分量的加速度。经分析和试验结果表明:该加速度计具有灵敏度较高、交叉干扰小,完全满足预期设计要求。