Position/force control of a manipulator mounted on a vehicle

To perform complex tasks with a mobile manipulator (consisting of a robot arm mounted on a vehicle) moving outdoors on an uneven ground, a first issue is to develop robust control laws for tasks in a vehicle-embedded frame. So, we have tested the behavior of the robot arm with classical control laws for several disturbances due to the motions of the vehicle. First, we have tested positioning tasks of the end effector with respect to its base reference frame with a Cartesian PID and a Cartesian Variable Structure Control—High Frequency. Then, we have tested hybrid and external force control structures for an experiment of following a surface situated on the vehicle. Results are presented in the form of graphs. © 1996 John Wiley & Sons, Inc.     

轻武器伺服跟踪系统的干扰补偿控制

为提高轻武器伺服跟踪系统的位置跟踪精度,提出一种基于干扰观测器的CMAC-PD复合控制方法。将摩擦、电机力矩波动和模型参数不确定性等影响系统性能的因素视为干扰,采用一种新型的干扰观测器对其进行估计并加以补偿。在此基础上,提出一种基于CMAC与PD的复合控制方法。对比仿真实验表明,基于干扰观测器的CMAC-PD复合控制能更有效地抑制干扰对轻武器伺服跟踪系统动态性能的影响,进而使系统获得更高的跟踪精度。     

Dynamic path tracking control of a vehicle on slippery terrain

This paper deals with accuracy and reliability for the path tracking control of a four wheel mobile robot with a double-steering system when moving at high dynamics on a slippery surface. An extended kinematic model of the robot is developed considering the effects of wheel–ground skidding. This bicycle type model is augmented to form a dynamic model that considers an actuation of the four wheels. Based on the extended kinematic model, an adaptive and predictive controller for the path tracking is developed to drive the wheels front and rear steering angles. The resulting control law is combined with a stabilization algorithm of the yaw motion which modulates the actuation torque of each four wheels, on the basis of the robot dynamic model. The global control architecture is experimentally evaluated on a wet grass slippery terrain, with speeds up to 7 m/s. Experimental results demonstrate enhancement of tracking performances in terms of stability and accuracy relative to the kinematic control.     

Adaptive tracking control of an MEMS gyroscope with H-infinity performance

Microelectromechanical systems (MEMSs) pose unique measurement and control problems compared with conventional ones because of their small size,low cost,and low power consumption.The vibrating gyroscope is one of those MEMS devices that have significant potential in many industry applications.When the MEMS gyroscope system is considered simultaneously with the coupling terms,the exogenous disturbances and the parameter variations,the controller design of this system becomes very challenging.This paper investigates the primary control problem of a perturbed vibrating MEMS gyroscope.A nonlinear robust adaptive control scheme is proposed for the drive axis of a vibrating MEMS gyroscope.By combining the dynamic surface control (DSC) method with the H-infinity disturbance attenuation technique,a simpler systematic design procedure is developed.The derived H-infinity controller has a simplified structure,and it can drive the drive axis to resonance,regulate the output amplitude of the drive axis to a desired value,and attenuate the generalized disturbances.The features of the derived controller are discussed and illustrated by the simulation of a closed-loop system.The analysis and simulation show that the obtained controller possesses good adaptability and robustness to system uncertainties.     

Nonlinear feedback control and trajectory tracking of vehicle

This paper mainly studies nonlinear feedback control applied to the nonlinear vehicle dynamics with varying velocity. The main objective of this study is the stabilisation of longitudinal, lateral and yaw angular vehicle velocities. To this end, a nonlinear vehicle model is developed which takes both the lateral and longitudinal vehicle dynamics into account. Based on this model, a method to build a nonlinear state feedback control is first designed by which the complexity of system structure can be simplified. The obtained system is then synthesised by the combined Lyapunov–LaSalle method. The simulation results show that the proposed control can improve stability and comfort of vehicle driving. Moreover, this paper presents a lemma which ensures the trajectory tracking and path-following problem for vehicle. It can also be exploited simultaneously to solve both the tracking and path-following control problems of the vehicle ride and driving stability. We also show how the results of the lemma can be applied to solve the path-following problem, in which the vehicle converges and follows a designed path. The effectiveness of the proposed lemma for trajectory tracking is clearly demonstrated by simulation results.     

作战用固定翼无人机落地姿态平衡控制系统设计

为解决当前控制系统存在对无人机落地高度测量误差大,落地各姿态角度大等问题,设计了作战用固定翼无人机落地姿态平衡控制系统。选用CMOS模拟多路复用器ADG508单芯片,对系统硬件电源电路、AD转换电路、信号采集电路、时钟复位电路、存储扩展电路及调试与接口电路进行优化,通过测量无人机落地姿态,完成系统软件设计,结合硬件与软件部分,实现作战用固定翼无人机落地姿态平衡控制系统的设计。实验结果表明,改进系统对无人机落地高度测量误差小,落地俯仰角、横滚角及偏航角小,具有较好的平衡控制效果,充分满足姿态测量需求。     

智能车辆自动超车系统的数据驱动路径跟踪约束控制

针对智能车辆自动超车系统,提出了一种新的数据驱动超车路径跟踪约束控制方案,系统控制方案的设计仅利用自动超车系统的输入/输出数据,并不包括车辆的模型信息,所以针对不同的车型均能够实现自动超车的数据驱动路径跟踪约束控制.在控制器的设计过程中,针对控制输入受变化范围和变化速率的限制,提出了一种新的动态抗饱和补偿器来解决饱和问题.最后给出了数据驱动约束控制与原型无模型自适应控制(model free adaptive control,MFAC)以及PID控制的仿真结果对比,结果表明,本文所提控制方案能够很好的完成自动超车过程的路径跟踪,且相比原型MFAC以及PID控制方案,本文方案具有更小的跟踪误差和更快的响应速度.     

Trajectory tracking control for a miniature fixed-wing unmanned air vehicle

This article considers the problem of trajectory tracking control for a miniature fixed-wing unmanned air vehicle (UAV). With the UAV equipped with longitudinal and lateral autopilots, we adopt a kinematic model that takes into account the fact that the heading of the UAV is controlled by its roll motion and the autopilot responses to air speed and roll control commands are first order in nature. Backstepping techniques are applied to derive air speed and roll control commands from known air speed and heading control laws that explicitly account for air speed and heading rate constraints of the UAV. Regarding inaccurately known autopilot constants, a parameter adaptation technique is used to estimate autopilot constants. High-fidelity simulation results on a six degree-of-freedom (DOF) 12-state fixed-wing UAV model are presented to show the effectiveness of our approach.     

Optimal feedback control for route tracking with a bounded-curvature vehicle

The problem of driving a vehicle along a given path is considered. The vehicle is supposed to move forward only, with a given velocity profile, and to have a bounded turning radius. Such a model, also known as 'Dubins' vehicle', is relevant to the kinematics of road vehicles as well as aircraft cruising at constant altitude, or sea vessels. We consider the optimal control problem consisting of minimizing the length travelled by the vehicle starting from a generic configuration to connect to a specified route. A feedback law is proposed, such that straight routes can be approached optimally, while the system is asymptotically stabilized. Experimental results are reported showing real-time feasibility of the proposed approach.     

移动车辆跟踪系统的设计与开发

面对日益增加的汽车数量和拥堵的交通环境,提出了利用无线通信技术采集移动车辆数据的应对方案。该方案利用低成本的芯片,设计了一个基于无线通信网的移动车辆跟踪系统,在嵌入单片机的车载终端与监测点间搭建简易、安全的无线通信协议。实验结果表明,该方法可行,具有较好的应用前景。     

嵌入式平台下的车辆跟踪系统设计

设计并实现了NVIDIA嵌入式平台Jetson TX2上的车辆跟踪系统。从摄像头采集YUV420格式的视频数据,然后将数据送到Tegra Parker硬件HEVC编码器进行编码,输出码流经过RTP封装后通过UDP广播发送,利用Gstreamer多媒体框架开发接收及解码程序,最后,针对获取的视频动态进行车辆的跟踪与显示。运行Yolo V2检测算法,对车辆进行检测,从而为跟踪系统提供跟踪对象。利用Kalman滤波算法对车辆的位置进行预测,再经过Meanshift算法进行车辆跟踪。系统能够实现帧率为60 f/s的超高清4K视频实时编码和传输,此系统中的HEVC硬件编码器编码速率比PC端x265编码器大3个数量级,PSNR比PC端x265编码器高6 dB,更加适用于智能交通中。     

考虑侧倾的无人车NMPC轨迹跟踪控制

针对高速行驶工况下,无人车转弯时的侧倾易导致车辆模型非线性程度增加,引起轨迹跟踪精度下降和状态失稳的问题,设计一种考虑车辆侧倾因素,基于非线性模型预测控制(NMPC)的无人车轨迹跟踪控制器.根据拉格朗日分析力学和车辆运动学,考虑车辆侧倾几何学和载荷转移效应,建立考虑侧倾因素的非线性车辆模型,包括车体动力学模型和修正的“Magic Formula”轮胎模型;基于此车辆模型,构建非线性模型预测控制器(NMPC)的预测模型,并设定控制器的线性、非线性约束,以保证车辆的运动状态处于稳定区域内.在Carsim和Simulink联合仿真平台上,验证车辆高速蛇形工况和双移线工况下的轨迹跟踪控制效果,仿真结果显示,所设计的控制器可有效改善高速弯道工况下的跟踪精度和车辆状态稳定性.     

MEMS gyroscope control system using a band-pass continuous-time sigma-delta modulator

This paper presents a MEMS gyroscope control system of using a high-order band-pass continuoustime sigma-delta modulator.Compared with a low-pass discrete-time sigma-delta modulator based solution,the band-pass modulator can considerably decrease the sampling frequency;moreover,the continuous-time architecture has an obvious advantage on PCB prototyping and shorter lead time of the implementation in hardware.System level simulations using MATLAB/Simulink show the proposed sixth order sigma-delta modulator can achieve a high SNR of 100 dB for an angular rate input with an amplitude of 200/s and a frequency of32 Hz.A PCB circuit implementation is simulated using Orcad/PSpice to analyze the stability,and implemented in hardware.Measurement of the power spectral density of the output bitstream reveals a noise floor of90 dBV/Hz1/2.The prototype is tested on a rate table with an angular rate input,verifying that the principle of the approach of using an electro-mechanical band-pass sigma-delta modulator control system for a MEMS gyroscope.     

Adaptive tracking control of an autonomous underwater vehicle

This paper presents the trajectory tracking control of an autonomous underwater vehicle(AUV). To cope with parametric uncertainties owing to the hydrodynamic effect, an adaptive control law is developed for the AUV to track the desired trajectory. This desired state-dependent regressor matrix-based controller provides consistent results under hydrodynamic parametric uncertainties.Stability of the developed controller is verified using the Lyapunov s direct method. Numerical simulations are carried out to study the efficacy of the proposed adaptive controller.     

基于陀螺仪与加速度计的二轮自平衡控制系统设计

为了实现二轮自平衡系统的稳定控制,提高系统姿态倾角的可靠性,提出了基于陀螺仪与加速度计的二轮自平衡系统控制方法.建立二轮自平衡系统的简易动力学模型,以Lyapunov方法对稳定性进行分析,得到系统稳定控制的条件,采用陀螺仪和加速度计采集姿态倾角数据,经融合滤波后得出高精度姿态倾角,最后控制二轮自平衡系统电机实现稳定运行.通过二轮自平衡控制系统的硬软件设计,成功验证了该方法的可行性.     

Trajectory tracking of a class of uncertain systems applied to vehicle platooning and antenna scanning systems

The tracking problem is considered for a recurring class of systems, such as the Cartesian robots with real actuators, some transportation systems, and scanning devices used for medical and engineering applications. Some theorems are proved to design a PD type controller, with a possible compensation signal, in order to track sufficiently smooth trajectories with a prescribed maximum error. The developed design methodology is illustrated through two engineering examples. The first example concerns the safety distance control of an electric vehicles fleet. The second example deals with the identification of an antenna scanning system and the prototype design of a new controller that provides better performance than the current one.     

陀螺壳体旋转角度的测控系统

介绍了一种应用多极旋转变压器和单片机实现的陀螺壳体旋转角度测控系统。给出了多极旋转变压器的测角原理,设计了相应的硬件电路和软件的算法与软件实现,并进行了相关的测角实验。实验结果表明：此系统测量误差小,性能稳定,能够满足整体性能要求,达到了预定的测量效果。     

高超声速飞行器有限时间饱和跟踪控制

针对高超声速飞行器纵向模型存在外界干扰和模型参数不确定性情形下的有限时间跟踪问题进行了研究分析.针对外界干扰上界已知,基于快速积分滑模理论,设计了有限时间快速积分滑模控制器.当外界干扰上界未知时,结合具有低通滤波器性能的自适应算法,通过引入辅助系统设计了实际有限时间自适应快速积分滑模控制器,能够处理输入饱和问题.对所设计的两个控制器利用李雅普诺夫理论给出了严格理论证明,得到整个闭环系统分别为有限时间稳定的、实际有限时间稳定的,并能够保证系统其它状态变量在较短的时间内趋于稳态值.对不同类型参考信号进行了数字仿真,进一步验证了所设计两个控制器的有效性和鲁棒性.     

环卫车辆轨迹跟踪系统的无模型自适应迭代学习控制

针对环卫车辆周期重复性工作特点,考虑模型时变以及未知扰动问题,提出一种基于无模型自适应迭代学习的环卫车辆轨迹跟踪控制方法.首先,针对环卫车辆建立了两轮移动机器人的运动学模型,然后,给出带时变参数和非线性不确定项的迭代域下全格式动态线性化数据模型,引入时间差分估计算法,设计基于最优性能指标的轨迹跟踪无模型自适应迭代学习控制方法,并进行仿真分析.结果表明,环卫车轨迹跟踪系统车身角随迭代增加超调减小,与传统迭代学习控制算法相比,具有松弛的条件限制和较好的鲁棒性,同时提高了控制系统精度.