Distributed observers for pose estimation in the presence of inertial sensory soft faults

Distributed Particle-Kalman Filter based observers are designed in this paper for inertial sensors (gyroscope and accelerometer) soft faults (biases and drifts) and rigid body pose estimation. The observers fuse inertial sensors with Photogrammetric camera. Linear and angular accelerations as unknown inputs of velocity and attitude rate dynamics, respectively, along with sensory biases and drifts are modeled and augmented to the moving body state parameters. To reduce the complexity of the high dimensional and nonlinear model, the graph theoretic tearing technique (structural decomposition) is employed to decompose the system to smaller observable subsystems. Separate interacting observers are designed for the subsystems which are interacted through well-defined interfaces. Kalman Filters are employed for linear ones and a Modified Particle Filter for a nonlinear non-Gaussian subsystem which includes imperfect attitude rate dynamics is proposed. The main idea behind the proposed Modified Particle Filtering approach is to engage both system and measurement models in the particle generation process. Experimental results based on data from a 3D MEMS IMU and a 3D camera system are used to demonstrate the efficiency of the method.     

A modified model reference adaptive control with application to MEMS gyroscope

Micro electro-mechanical systems (MEMS) are increasingly being used in measurement and control problems due to their small size, low cost, and low power consumption. The vibrating gyroscope is a MEMS device that will have a significant impact on stability control systems in the transportation industry. This paper investigates the application of a modified model reference adaptive control for MEMS gyroscope. Using this adaptive control algorithm, an estimation of the angular velocity and the damping and stiffness coefficients in real time is easily computable. Changing the conventional model reference input makes it feasible to utilize a low pass filter to remove unwanted oscillations caused by high adaptation gain. This new adaptive control technique enables quick compensation for large changes in the system dynamics, providing consistent estimation of gyroscope parameters including angular velocity and large robustness to parameter variations and external disturbances. The asymptotic stability of the mentioned adaptive controller is guaranteed using the Lyapunov direct method. Numerical simulation is presented to verify the effectiveness of the proposed control scheme.     

基于位姿反馈的三臂空间机器人抓捕轨迹规划

以三臂空间机器人为研究对象,针对经历奇异位形时出现的位姿误差问题,提出一种基于位姿误差反馈的轨迹规划算法。根据系统一般运动学方程并结合动量守恒方程建立系统运动学模型,利用位姿期望指令得到误差运动方程。以关节角速度为控制量,设计了基于位姿误差反馈的控制率,使闭环系统的跟踪误差按指数速度收敛。该方法能够减小机器人奇异点邻域内的位姿跟踪误差,且在离开奇异区域后能完全消除误差。仿真结果证明了该方法的有效性。     

Attitude output feedback control for rigid spacecraft with finite-time convergence

The main problem addressed is the quaternion-based attitude stabilization control of rigid spacecraft without angular velocity measurements in the presence of external disturbances and reaction wheel friction as well. As a stepping stone, an angular velocity observer is proposed for the attitude control of a rigid body in the absence of angular velocity measurements. The observer design ensures finite-time convergence of angular velocity state estimation errors irrespective of the control torque or the initial attitude state of the spacecraft. Then, a novel finite-time control law is employed as the controller in which the estimate of the angular velocity is used directly. It is then shown that the observer and the controlled system form a cascaded structure, which allows the application of the finite-time stability theory of cascaded systems to prove the finite-time stability of the closed-loop system. A rigorous analysis of the proposed formulation is provided and numerical simulation studies are presented to help illustrate the effectiveness of the angular-velocity observer for rigid spacecraft attitude control.     

基于最小分辨率的MEMS陀螺漂移抑制方法研究

针对油气井MEMS陀螺定向测斜仪存在的漂移大,精度较低的问题,本文从实际工程应用角度出发,在研究MEMS陀螺仪输出信号漂移特性的基础上,提出了基于最小分辨率的MEMS陀螺漂移抑制方法,利用输出采样的差分值,从MEMS陀螺输出中将传感信号和漂移信号分离,同时通过静态测点对漂移进行估计.实验表明,该方法大幅提高了仪器测量精度,使定向精度提高50％以上,同时该方法为其它类似传感器漂移抑制提供了一种有益的参考.     

基于修正粒子滤波的MEMS传感器飞行器姿态解算

针对单一采用 MEMS传感器解算飞行器姿态无法克服系统非线性噪声干扰的问题,提出了一种基于修正粒子滤波的 MEMS传感器飞行器姿态解算方法.首先,利用共轭梯度法减小陀螺仪漂移误差,然后,利用加权粒子构造概率密度函数以更新粒子权值,得到优化状态估计值;再将共轭梯度法与修正粒子滤波进行融合,确定加权因子,同时以 STM32与 MEMS传感器为核心设计姿态解算系统.实验结果表明,该方法优化了飞行器静态与动态性能,姿态解算性能良好,系统过渡时间短,跟踪特性较好,且增强了系统的鲁棒性与稳定性.     

基于两轮自平衡机器人组合定位方法的研究

对两轮自平衡机器人的运动控制过程中相对定位的问题进行了研究.根据两轮自平衡车的特点,对诸如车轮打滑、碰撞、越障及转向等运动情况下的位置传感器和姿态传感器的信号进行了分析,提出了将光电码盘、MEMS陀螺仪与MEMS加速度计数据融合的方法,对机器人的位姿进行检测估计,从而解决了采用传统的单一位置传感器对机器人测程不准确的问题.同时也降低了陀螺仪、加速度计固有漂移的不利影响,提高了两轮自平衡机器人的定位精度.通过对两轮机器人分别进行直线运动实验、越障实验和异常碰撞试验,验证了两轮自平衡机器人组合定位方法的合理性和有效性.     

基于刚度轴偏角预估机制的 MEMS 多环谐振陀螺全闭环控制方法

针对微机电系统多环谐振陀螺正交闭环回路存在控制误差问题,提出一种基于刚度轴偏角预估机制的多环陀螺全闭环控制方法。该方法通过对微机电系统多环谐振陀螺刚度轴偏角预估,实现正交闭环回路参数自动优化调整。同时,提出了基于刚度轴偏角预估机制的全数字化闭环控制方法,实现微机电系统多环谐振陀螺的驱动、检测、正交、模态匹配环路的全闭环控制。该方法可提升正交闭环回路信噪比,增强陀螺正交漂移的抑制能力,降低陀螺零偏输出,改善陀螺的零偏不稳定性。实验结果表明,采用本文提出的基于刚度轴偏角预估机制的全闭环控制方法后,微机电系统多环谐振陀螺的零偏输出由0.201°/s降低为0.021 3°/s,零偏不稳定性由39.42°/h降低为1.237°/h,分别降低了9.44倍和31.86倍,验证了该方法对提升微机电系统多环谐振陀螺仪性能的有效性。     

Investigating the effects of quadrature error in parametrically and harmonically excited MEMS rate gyroscopes

Some factors like environmental conditions and manufacturing errors affect performance of a MEMS rate gyroscope. Because they may result to parameter mismatch between the designed gyroscope and the fabricated one. The Parametrically excited gyros are more robust to these changes than the harmonically excited gyros. However, these types of gyros also experience reduction in their accuracy in angular velocity determination due to these changes. One of parameters that affect the accuracy of the gyroscope is quadrature error that here, its effect in the accuracy of angular velocity determination is investigated in two typically designed harmonically and parametrically excited MEMS gyroscopes. The studies are done solving the gyroscopes’ equations analytically and numerically after addition of quadrature error. Finally, it’s found that the quadrature error reduces the accuracy of the gyroscope. Accuracy reduction (equivalent to output error increasing) decreases with increasing angular velocity or decreasing quadrature error almost the same for two types of gyroscope.     

MEMS陀螺与编码器在机器人自主定位中的应用

为提高微机械陀螺仪输出精度及移动机器人定位精度,研究了基于微机械陀螺仪与光电编码器的移动机器人自主定位方法。实时小波滤波法算法去除微机械陀螺仪输出数据噪声;通过微陀螺精度校正平台,用加权最小二乘支持向量回归机算法对微机械的先验数据作回归运算,构造先验回归决策函数,运用回归决策函数补偿微机械陀螺仪输出误差,提高微机械陀螺仪的角速率输出准确度;实验证实了方法能较好提高了MEMS陀螺仪的准确度,可以应用于移动机器人的自主定位之中。     

Robust adaptive control for a MEMS vibratory gyroscope

This paper presents an adaptive sliding mode controller for a microelectromechanical systems (MEMS) vibratory z-axis gyroscope. The proposed adaptive sliding mode controller can real-time estimate the angular velocity and the damping and stiffness coefficients. The stability of the closed-loop system can be guaranteed with the proposed adaptive sliding mode control strategy. The numerical simulation for MEMS gyroscope is investigated to show the effectiveness of the proposed control scheme. It is shown that the proposed adaptive sliding mode control scheme offers several advantages such as real-time estimation of gyroscope parameters and large robustness to parameter variations and external disturbance.     

Robocup中型足球机器人运动控制

为使Robocup中型足球机器人快速准确地跟踪目标,本文分析了机器人的运动学和动力学模型,设计了一套智能运动控制系统。机器人通过全景视觉系统测量目标位置,用零阶Sugeno型模糊控制器设定电机的转速,最后由电机伺服控制器进行电机速度电流双闭环控制。实验表明该控制系统满足机器人运动快速性和准确性的要求,成功应用于SCUT-Ⅱ型足球机器人。     

一种陀螺与罗盘组合导航系统的故障检测方法

为了提高MEMS陀螺和磁罗盘组合导航系统的可靠性,减少各种干扰和故障对导航精度的影响,提出了一种及时、精确、有效的故障检测方法。该方法首先对正常工作时的MEMS陀螺和磁罗盘信号中的各种噪声进行分析;然后针对组合系统中的常见故障,从陀螺和磁罗盘航向信息中提取出短时间内两者航向变化量差值的均值、均值的一阶差分量及二阶差分量作为故障检测量,用以区分识别不同的故障源;最后使用预警模式,来减小故障检测过程中的延迟影响,提高故障检测的及时性。实验结果表明,此方法可以及时、准确地区分识别出组合系统中零偏、速率斜坡故障以及两种磁干扰,有效地降低了干扰和故障的引入误差。     

卡尔曼滤波在MEMS惯性姿态测量中的应用

由于测控成本和有效载荷的限制,一般采用微机电系统(MEMS)惯性传感器来测量小型无人机的飞行姿态。在MC9S12XS128单片机上通过嵌入式软件编程实现了卡尔曼滤波算法,并在JZJ-1型自准直仪转台上对MEMS加速度计和陀螺仪的输出信号进行了数据融合试验,较好地解决了MEMS惯性测量系统的零漂和机械振动干扰问题。     

一种稳定跳跃型机器人的设计与空中姿态控制

针对现有跳跃机器人跳跃时空间姿态旋转问题,从结构与运动控制上入手,设计一种稳定跳跃型机器人。基于弹簧倒立摆跳跃模型在平行四杆机构的基础上设计了一种新型八连杆机构,并利用离合式行星轮结构设计了一种靠卷绳实现能量蓄积与释放装置。利用拐点圆及最小残差理论对末端轨迹进行了近似直线优化处理,并建立了跳跃结构的运动学、动力学模型,进行了跳跃仿真测试。设计了基于模糊PID控制理论的双闭环反馈控制系统,并搭建联合仿真模型从结构动力学及姿态控制系统上进行整体仿真测试。结果表明机器人具备结构上的稳定起跳基础,并通过空中姿态控制实现跳跃后稳定姿态的保持,整体实现了稳定跳跃。     

A novel adaptive sliding mode control with application to MEMS gyroscope

This paper presents a new adaptive sliding mode controller for MEMS gyroscope; an adaptive tracking controller with a proportional and integral sliding surface is proposed. The adaptive sliding mode control algorithm can estimate the angular velocity and the damping and stiffness coefficients in real time. A proportional and integral sliding surface, instead of a conventional sliding surface is adopted. An adaptive sliding mode controller that incorporates both matched and unmatched uncertainties and disturbances is derived and the stability of the closed-loop system is established. The numerical simulation is presented to verify the effectiveness of the proposed control scheme. It is shown that the proposed adaptive sliding mode control scheme offers several advantages such as the consistent estimation of gyroscope parameters including angular velocity and large robustness to parameter variations and external disturbances.     

基于ADAMS的五自由度机器人运动学仿真

介绍了基于ADAMS的五自由度机器人的三维建模方法,并用ADAMS的运动仿真功能对五自由度机器人的运动特性进行了仿真分析,给出了机器人在典型运动状态下,手部末端的位移、速度及加速度等特性曲线,为机器人运动控制及优化设计提供参考依据。     

焊接机器人操作臂空间路径的数学建模

通过对焊接机器人操作臂关节自由度的位置、速度和加速度的时间历程计算,利用关节空间规划方法逆运动学理论,将运动路径的中间点转换成一系列期望的关节角,推演出经过各中间点并终止于目标点的n个关节的高阶多项式函数,从而获得机器人操作臂在多维空间中所期望的运动模式,为机器人运动仿真和结构设计提供依据。     

实现装载机车架流水线装配

通过对装配现场的分析,分别设计制作了移动式全自动前后车架装配板链线,对延续多年的前后车架地摊搭架式装配进行了重大改进,使得员工工作环境得到了明显改善,工作效率得到大幅提升。设计了三维立式工作吊架,通过制作工装保证轴承的位置,并通过小型油压机将轴承快速压型到位,效率高,大大降低员工的劳动强度,同时不使用铜棒敲击,避免了噪声,改善了装配现场环境,提高了轴承的装配精度。装配产能也提升到了8分钟/台,装配效率提高50%。     

HP6机器人运动学动力学分析及运动仿真研究

提出了hp6机器人的基坐标和运动坐标系统和运动学动力学模型,导出了基于D-H参数法的该机器人运动方程和拉格朗日动力学方程,并完成了Matlab环境下的运动学仿真分析,所得结果可应用于机器人关节驱动装置设计及机器人轨迹规划的动力学优化设计.