海参捕捞装置导航中低成本陀螺仪的降噪研究与试验

针对MEMS陀螺仪输出信号中含有的随机漂移噪声造成海参捕捞装置惯性导航精度明显下降的问题,采用时间序列分析法和Kalman滤波算法,对MEMS陀螺仪随机漂移噪声的削减问题进行研究。以MEMS惯性测量单元的实测数据和三维电子罗盘测量的姿态角为样本,对本研究的低成本陀螺仪的降噪效果进行测试,试验结果表明:1)经过降噪处理后的陀螺仪随机漂移信号的方差比陀螺仪原始采样信号的方差降低1个数量级,显著改善了陀螺仪随机漂移数据的精密度;2)以高精度三维电子罗盘实测的姿态角作为参考基准,将降噪后的陀螺仪随机漂移数据导入捷联惯导姿态更新算法程序,在300s时间内,解算出的俯仰角、横滚角和航向角的均方根误差RMSE全部小于1°;与降噪前相比,相应的俯仰角、横滚角、航向角的RMSE分别降低了170.5、97.6和42.5倍,明显提高了惯性导航精度。     

基于AR模型的MEMS陀螺误差补偿方法研究

针对MEMS(Microelectro Mechanical Systems）陀螺具有成本低、体积小但误差较大的问题,探讨MEMS陀螺的误差补偿方法。基于AR模型方法,采集MEMS陀螺原始信号,对原始信号进行预处理,利用预处理后的数据建立陀螺的AR(Auto Regressive)模型,辨识出模型参数。利用该模型对陀螺信号进行误差补偿,计算出陀螺的较精确值。通过对某MEMS陀螺误差补偿的静态和动态试验表明,提出的方法能够有效地减小误差,提高陀螺的测量精度。     

基于小波分析的陀螺随机漂移建模与滤波

采用基于小波分析提取信号趋势项的方法,对实测三浮陀螺漂移数据的趋势项加以提取,并对其残差进行建模。在建立了时序模型的基础上进行卡尔曼滤波器设计,对三浮陀螺的随机漂移数据进行卡尔曼滤波,结果表明,滤波方法有效地抑制了陀螺的随机误差。     

Temperature Measurement and Compensation for the Angle Error of Gyro

The temperature drift is one of the most important error sources and influences the measuring accuracy of gyroscope greatly. The more exact temperature is measured, the more accurate angular error could be compensated. So the improvement of temperature measurement is significant to the system accuracy. A temperature measurement and compensation system was designed and experimented. The temperature of solid vibration gyroscope developed by ourselves was measured, analyzed and corrected. At last, the mean square deviation reduced from 31. 418 2 to 0.547 7, The experiment results proved that the design of soft and hardware is effective.     

Superconductivity of Single-Walled Carbon Nanotubes

The electric-arc technique used to generate single-walled carbon nanotubes (SWCNTs) is introduced. Especially, the superconductivity of SWCNTS is concerned. The samples of single-walled carbon nanotubes are suspended between two superconducting electrodes and their super-currents may be observed under special conditions. It is called 'proximity-induced method'. With the method, some experiments show that SWCNTs have higher critic super-currents, and the temperature and magnetic field dependence of the critic currents exhibits unusual features.     

温室移动机器人轨迹控制系统的设计

以温室移动机器人的轨迹控制为主要目标,研究了线性控制算法在机器人轨迹控制中的具体实现,论证了其可行性,并分析了算法的稳定性约束条件,通过仿真分析了控制参数对运动轨迹的影响.将该算法应用到实际的机器人控制中,设计出基于陀螺仪和光电编码器的温室移动机器人控制系统.     

Development of a low-cost attitude sensor for agricultural vehicles

The objective of this research was to develop a low-cost attitude sensor for agricultural vehicles. The attitude sensor was composed of three vibratory gyroscopes and two inclinometers. A sensor fusion algorithm was developed to estimate tilt angles (roll and pitch) by least-squares method. In the algorithm, the drift error of the gyroscopes was estimated using the inclinometers. In addition to tilt angles, the attitude sensor also estimated the absolute heading angle and position with inclination error correction by integrating a GPS. Tests were conducted on a flat field, a sloping ground and a bumpy road. Results showed that the attitude sensor was able to estimate the roll angle with the maximum root mean square error of 0.43°, the pitch angle with 0.61° and the heading angle with 0.64°. Moreover, the attitude sensor dramatically improved the positioning accuracy from 25.9 cm to 3.0 cm in the sloping ground test and from 8.4 cm to 3.7 cm in the bumpy road test. The proposed technology used in the attitude sensor will help to develop advanced agricultural applications.     

基于MEMS传感器的两轴姿态调整系统设计与试验

在精准农业生产过程中,传感器实时采集作物信息或环境状态,传感器与作物的相对位置,直接影响到采集数据的准确性,及后期处理的效率,甚至影响到作业的效果。而田间道路、垄间颠簸,会影响传感器与作物相对位置,造成信息失真和不准确,为了减少地面不平整干扰对传感器位置的影响,该文提出了基于MEMS传感器步进电机驱动的两轴姿态调整系统。本研究分析了系统的工作原理和控制方法,以陀螺仪、重力加速度计为姿态测量元件,步进电机为驱动部件,设计基于单片机控制的两轴姿态调整系统平台软硬件结构。系统采用单片机对陀螺仪和加速度计信息的实时采样,建立了多传感信息的融合算法和姿态判定模型,可以实时分析检测对象姿态,并输出控制步进电机,对平台姿态进行补偿调整,保持控制对象的相对惯性空间方位不变,实现了平台姿态平衡的快速控制。同时系统加入了绝对位置传感器,实现初始工作状态的自动复位。测试试验结果表明,系统运行稳定,单轴姿态调整精度在平整坡路状态下最大误差在0.5°以内,在田间颠簸路况运行下最大误差在3.0°以内,能够满足信息采集和检测过程中姿态自动调整、保持相对位置的控制要求。利用该控制系统,能够提高信息采集的准确性,在精准农业生产中具有应用作用。     

基于RTK-GNSS和MEMS陀螺仪的车辆航向角测量技术

【目的】更好地满足车辆自动驾驶时航向角测量的精度要求。【方法】提出卡尔曼滤波算法,把实时动态–全球导航卫星系统(RTK-GNSS)测量出来的经纬度和高程经过高斯投影转换为高斯平面坐标,和微电子机械系统(MEMS)陀螺仪测得的累积航向角进行融合处理,最终得到车辆更为精准的航向角。【结果】融合后的航向角度曲线既保持了GNSS航向的整体变化趋势,也保持了陀螺仪航向的细部变化趋势,且较GNSS和陀螺仪所得曲线更为平滑,可以跟踪车辆180°调头的转弯动作。【结论】卡尔曼滤波算法可以实时在线且精准地测得车辆航向角数据,精度较GNSS测量结果提高80%以上。     

拖拉机极限态侧翻回稳陀螺主动控制系统设计与试验

针对拖拉机在斜坡行驶中受复杂路况激扰易引发的极限态侧翻失稳问题,基于单框架控制力矩陀螺设计了主动侧翻回稳控制系统。以单侧轮胎离地侧翻工况为主要研究对象,利用欧拉-拉格朗日方程构建了整机和力矩陀螺耦合系统的非线性侧倾动力学方程,并基于反步设计法推导了状态反馈控制律。该控制律可依据侧翻危险程度实时调整陀螺转子的进动角速度,定量输出侧翻回稳力矩。以环境障碍物和整机行驶速度为变量,开展了极限态侧翻失稳控制比例模型试验。结果表明,与无控制组相比,采用力矩陀螺主动侧翻回稳系统可显著调控拖拉机的侧倾过程,且在实际侧倾角大于静态临界侧倾角9.58%时仍能有效实现侧翻回稳。研究表明,提出的控制方法可适用于不同危险程度的极限侧翻工况,为拖拉机主动安全控制提供理论依据和技术参考。