基于改进UKF算法的移动机器人定位方法研究

针对移动机器人在多传感器融合定位过程中因噪声统计特性未知或不准确引起的定位精度不高的问题,提出了一种基于Sage-Husa滤波改进的无损卡尔曼滤波(UKF)移动机器人定位算法。首先建立了移动机器人定位相关模型;然后根据噪声统计特性时变特点利用Sage-Husa中的噪声估计器,对状态噪声和量测噪声进行自适应地估计,减小扰动噪声给定位解算带来的误差;接着在状态更新时引入收敛因子,加快算法收敛速度;最后将UKF算法和改进的UKF算法应用到实验室移动机器人中进行仿真实验。实验结果表明,所提出的算法对状态扰动具有较强的抵制能力,对机器人定位的准确性与稳定性的提升具有显著效果。     

WSNs网络下移动机器人HuberM-CKF离散滤波定位*

针对传统移动机器人定位算法精度不高的问题,提出一种基于无线传感器网络HurbM-CKalman滤波(HCKF)算法的移动机器人定位算法。利用HurbM极大似然估计代价函数,求解线性化后CKF观测矩阵,从而解决CKF滤波算法在未知非高斯白噪声干扰下估计精度不高问题。然后,在体育馆基于WSNs网络构建了移动机器人定位实验环境,并结合移动机器人动力学模型,对HCKF、CKF算法的定位精度进行对比。结果显示,在不含噪声干扰和含未知噪声干扰两种情况下,HCKF算法定位精度分别比CKF算法提高7%和15%。     

视觉与惯性传感器融合的隐式卡尔曼滤波位置估计算法

机器人对自身位置的实时感知在机器人技术中非常重要.本文主要研究机器人技术中一类基于视觉与惯性传感器的位置估计问题.与传统的状态估计问题不同的是,所研究位置估计问题为带有隐式观测方程的线性状态估计问题.为此提出一种能够解决此类估计问题的隐式卡尔曼滤波器,并给出了详细的滤波器设计过程.另外采用扩展变量法将加速度信息中的偏移量作为滤波器状态来估计,以补偿其对位置估计结果的影响.仿真结果显示,所给出的隐式卡尔曼滤波器收敛,加速度偏移带来的影响被有效的补偿.     

单天线GPS/陀螺仪组合测姿方法研究

针对低成本惯性测量系统的精度容易受引擎震动、陀螺仪漂移的影响,提出了一种适用于活塞引擎的小型UAV姿态测量方法;此方法整合陀螺仪与单天线GPS进行姿态测量,采用以四元数为基础的扩展卡尔曼滤波(EKF)来进行传感器信息融合;利用陀螺仪测得的角速度更新四元数,使用GPS信息所计算的伪姿态来更新滤波器的测量值;仿真结果表明所提出的方法即使在陀螺仪漂移和伪姿态包含噪声的情况下,也拥有较好的长期和短期精度,提升了姿态测量的精度与可靠度。     

基于WT-UKF 的PDR/GPS 组合定位算法

针对行人航迹推算(PDR) 与全球定位系统(GPS) 组合定位问题, 提出一种基于小波变换(WT) 的无迹卡尔曼滤波(UKF) 改进算法, 对PDR 和GPS 定位结果进行数据融合. 建立PDR/GPS 组合定位系统数学模型, 采用小波变换对运动加速度信号噪声特性进行在线估计, 以更新UKF 的协方差矩阵. 所提出的WT-UKF 滤波算法弥补了传统UKF 算法因人为假定信号噪声为高斯白噪声而影响滤波效果和精度的缺陷. 实验结果表明, 使用WT-UKF 滤波算法对PDR/GPS 进行数据融合时稳定性更强, 精度更高.     

一种Sage-Husa和可观测度的滤波算法研究

针对目标跟踪中过程噪声统计特性未知和状态分量可观测度差而导致滤波精度不高甚至滤波发散的问题,提出了一种复合自适应滤波算法.我该算法在滤波过程中,利用Sage-Husa噪声估计器在线估计过程噪声,用可观测度分析方法抑制状态分量可观测度差对滤波器的不良影响.在滤波过程中实时估计和修正过程噪声的统计特性,同时对观测度差的分量...     

改进的非线性鲁棒EKF算法及其应用

非线性系统由于噪声统计的不确定性,经常使得常规扩展Kalman滤波器滤波误差放大,甚至引起滤波发散,为此提出了一种采用虚拟噪声的补偿方法,对时变的噪声统计进行在线估计且加以补偿,提高了非线性滤波的鲁棒性。以星载GPS定轨为研究对象,应用该方法进行滤波定轨,结果表明,方法具有滤波稳定性和定轨结果的精确性。     

未知噪声统计下多模型概率假设密度粒子滤波算法

针对传统多目标概率假设密度滤波(PHD) 器在噪声先验统计未知或不准确时滤波精度下降甚至丢失目标的问题, 设计一种自适应多模型粒子PHD(MMPHD) 滤波算法. 该算法利用多模型近似思想, 推导出一种多模型概率假设密度估计器, 不仅能估计多目标状态, 而且能实时估计未知且时变的噪声参数, 并采用蒙特卡罗方法给出了MMPHD闭集解. 仿真实例表明, 所提出的算法具有应对噪声变化的自适应能力, 可有效提高目标跟踪精度.

     

基于MIT规则的自适应扩展集员估计方法

用于非线性椭球估计的自适应扩展集员(Adaptive extended set-membership filter, AESMF)算法在实际应用中存在着过程噪声设定椭球与真实噪声椭球失配的问题, 导致滤波器的估计出现偏差甚至发散. 本文提出了一种基于MIT规则过程噪声椭球最优化的自适应扩展集员估计算法(MIT-AESMF), 用于解决非线性系统时变状态和参数的联合估计和定界中过程噪声无法精确建模问题的新算法. 本算法通过MIT优化规则,在线计算使一步预测偏差包络椭球最小化的过程噪声包络椭球, 以此保证滤波器健康指标满足有效条件; 最后, 采用地面移动机器人状态和动力学参数联合估计验证了所提出方法的有效性.     

基于强跟踪滤波器及小波变换的非线性系统参数辨识及应用

本文采用强跟踪滤波器为主要框架, 通过线性化和状态扩展解决非线性系统时变参数和状态的估计问题. 在普通强跟踪滤波器的基础上, 以小波变换估计量测噪声, 采用滤波增益调整系数解决过跟踪问题, 给出了主要的计算公式和参数的取值方法, Monte Carlo仿真和在弹道方程参数辨识中的应用结果表明, 本方法不但对突变参数具有强跟踪能力, 在噪声方差发生变化的情况下, 仍可以对非线性参数进行准确的辨识, 状态与参数估计精度高于 普通的强跟踪滤波器.     

Mobile robot localization with gyroscope and constrained Kalman filter

The odometry information used in mobile robot localization can contain a significant number of errors when robot experiences slippage. To offset the presence of these errors, the use of a low-cost gyroscope in conjunction with Kalman filtering methods has been considered by many researchers. However, results from conventional Kalman filtering methods that use a gyroscope with odometry can unfeasible because the parameters are estimated regardless of the physical constraints of the robot. In this paper, a novel constrained Kalman filtering method is proposed that estimates the parameters under the physical constraints using a general constrained optimization technique. The state observability is improved by additional state variables and the accuracy is also improved through the use of a nonapproximated Kalman filter design. Experimental results show that the proposed method effectively offsets the localization error while yielding feasible parameter estimation.     

Mobile robot localization based on PSO estimator

Localization is fundamental to autonomous operation of the mobile robot. A particle filter (PF) is widely used in mobile robot localization. However, the robot localization based PF has several limitations, such as sample impoverishment and a degeneracy problem, which reduce significantly its performance. Evolutionary algorithms, and more specifically their optimization capabilities, can be used in order to overcome PF based on localization weaknesses. In this paper, mobile robot localization based on a particle swarm optimization (PSO) estimator is proposed. In the proposed method, the robot localization converts dynamic optimization to find the best robot pose estimate, recursively. Unlike the localization based on PF, the resampling step is not required in the proposed method. Moreover, it does not require noise distribution. It searches stochastically along the state space for the best robot pose estimate. The results show that the proposed method is effective in terms of accuracy, consistency, and computational cost compared with localization based on PF and EKF.     

具有非完整约束移动机器人的超宽带-惯导-里程计融合定位与能观测性分析

为解决现有超宽带-惯导组合定位系统在轮式移动机器人的定位精度低、依赖高精度IMU等问题,提出了一种采用误差状态卡尔曼滤波融合超宽带-惯导-里程计的定位算法,利用里程计的线速度测量和由非完整约束隐含的伪测量,提高了移动机器人的位置和姿态估计精度. 同时,对于由多传感器测量模型组成的非线性系统,通过基于李导数的能观性秩条件分析方法对该系统的能观测性进行了详细的理论分析与数学证明,得到了系统局部弱可观的条件,从而确定了系统状态可以被无偏估计所需要的测量输出以及控制输入. 仿真结果表明,在满足能观测性条件时,本文提出的方法能够有效地获得移动机器人较准确的六自由度位姿,且相比传统方法显著提升了定位精度.     

A Localization Algorithm for Autonomous Mobile Robots via a Fuzzy Tuned Extended Kalman Filter

The capability to acquire the position and orientation of an autonomous mobile robot is an important element for achieving specific tasks requiring autonomous exploration of the workplace. In this paper, we present a localization method that is based on a fuzzy tuned extended Kalman filter (FT-EKF) without a priori knowledge of the state noise model. The proposed algorithm is employed in a mobile robot equipped with 16 Polaroid sonar sensors and tested in a structured indoor environment. The state noise model is estimated and adapted by a fuzzy rule-based scheme. The proposed algorithm is compared with other EKF localization methods through simulations and experiments. The simulation and experimental studies demonstrate the improved performance of the proposed FT-EKF localization method over those using the conventional EKF algorithm.     

Estimation and control of the attitude of a dynamic mobile robot using internal sensors

For the control of a dynamic mobile robot, the attitude in gravity space is an important state of the robot. Usually, the attitude is difficult to detect by simply using the signals from sensors. For example, an external sensor contacting the ground suffers disturbances from the roughness of the ground; the integration of a gyroscope signal has the problem of drift; an inclination sensor does not indicate the direction of gravity when acceleration exists. To solve these problems, we propose a control method in which the attitude of a mobile robot is estimated by an observer considering the robot dynamics and using only the information obtained by internal sensors. We applied this method to a wheeled inverted pendulum as an example of a dynamic mobile robot. The estimation of the attitude was made with good accuracy using the signals from the rate gyroscope and the motor encoder, and the control of stable running of the pendulum on a flat level plane worked successfully. We also realized the running control of a pendulum on an unknown rough road using the estimation of the slope gradient made by the observer. Thus, the effectiveness of the proposed method was demonstrated experimentally.     

Mobile-robot pose estimation and environment mapping using an extended Kalman filter

In this paper an extended Kalman filter (EKF) is used in the simultaneous localisation and mapping (SLAM) of a four-wheeled mobile robot in an indoor environment. The robot’s pose and environment map are estimated from incremental encoders and from laser-range-finder (LRF) sensor readings. The map of the environment consists of line segments, which are estimated from the LRF’s scans. A good state convergence of the EKF is obtained using the proposed methods for the input- and output-noise covariance matrices’ estimation. The output-noise covariance matrix, consisting of the observed-line-features’ covariances, is estimated from the LRF’s measurements using the least-squares method. The experimental results from the localisation and SLAM experiments in the indoor environment show the applicability of the proposed approach. The main paper contribution is the improvement of the SLAM algorithm convergence due to the noise covariance matrices’ estimation.     

Robust weighted state fusion Kalman estimators for networked systems with mixed uncertainties

This paper is concerned with robust weighted state fusion estimation problem for a class of time-varying multisensor networked systems with mixed uncertainties including uncertain-variance multiplicative and linearly correlated additive white noises, and packet dropouts. By augmented state method and fictitious noise technique, the original system is converted into one with only uncertain noise variances. According to the minimax robust estimation principle, based on the worst-case system with the conservative upper bounds of uncertain noise variances, four weighted state fusion robust Kalman estimators (filter, predictor and smoother) are presented in a unified form that the robust filter and smoother are designed based on the robust Kalman predictor. Their robustness is proved by the Lyapunov equation approach in the sense that their actual estimation error variances are guaranteed to have the corresponding minimal upper bounds for all admissible uncertainties. Their accuracy relations are proved. The corresponding robust local and fused steady-state Kalman estimators are also presented, and the convergence in a realization between the time-varying and steady-state robust Kalman estimators is proved by the dynamic error system analysis (DESA) method. Finally, a simulation example applied to uninterruptible power system (UPS) shows the correctness and effectiveness of the proposed results.     

Robust face tracking control of a mobile robot using self‐tuning Kalman filter and echo state network

This paper presents a novel design of face tracking algorithm and visual state estimation for a mobile robot face tracking interaction control system. The advantage of this design is that it can track a user's face under several external uncertainties and estimate the system state without the knowledge about target's 3D motion‐model information. This feature is helpful for the development of a real‐time visual tracking control system. In order to overcome the change in skin color due to light variation, a real‐time face tracking algorithm is proposed based on an adaptive skin color search method. Moreover, in order to increase the robustness against colored observation noise, a new visual state estimator is designed by combining a Kalman filter with an echo state network‐based self‐tuning algorithm. The performance of this estimator design has been evaluated using computer simulation. Several experiments on a mobile robot validate the proposed control system. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

A human–robot interface for mobile manipulator

This paper presents a remote manipulation method for mobile manipulator through operator’s gesture. In particular, a track mobile robot is equipped with a 4-DOF robot arm to grasp objects. Operator uses one hand to control both the motion of mobile robot and the posture of robot arm via scheme of gesture polysemy method which is put forward in this paper. A sensor called leap motion (LM), which can obtain the position and posture data of hand, is employed in this system. Two filters were employed to estimate the position and posture of human hand so as to reduce the inherent noise of the sensor. Kalman filter was used to estimate the position, and particle filter was used to estimate the orientation. The advantage of the proposed method is that it is feasible to control a mobile manipulator through just one hand using a LM sensor. The effectiveness of the proposed human–robot interface was verified in laboratory with a series of experiments. And the results indicate that the proposed human–robot interface is able to track the movements of operator’s hand with high accuracy. It is found that the system can be employed by a non-professional operator for robot teleoperation.     

纯方位角目标跟踪及移动平台可观性控制方法

为了解决未知环境下的单目视觉移动机器人目标跟踪问题,提出了一种将目标状态估计与机器人可观性控制相结合的机器人同时定位、地图构建与目标跟踪方法。在状态估计方面,以机器人单目视觉同时定位与地图构建为基础,设计了扩展式卡尔曼滤波框架下的目标跟踪算法;在机器人可观性控制方面,设计了基于目标协方差阵更新最大化的优化控制方法。该方法能够实现机器人在单目视觉条件下对自身状态、环境状态、目标状态的同步估计以及目标跟随。仿真和原型样机实验验证了目标状态估计和机器人控制之间的耦合关系,证明了方法的准确性和有效性,结果表明:机器人将产生螺旋状机动运动轨迹,同时,目标跟踪和机器人定位精度与机器人机动能力成正比例关系。