增量式自适应逆控制及在过热汽温中的应用

被控对象的迟延和惯性特性是影响控制系统品质的重要因素之一.从常规PID增量式控制算法入手,在对具有迟延和惯性被控对象的动态特性进行定性分析的基础上,给出了一种改进型增量式控制算法的表达式;分析了被控对象校正逆模型的参数向量与控制器的参数向量之间的联系,进而将控制器的荻取与被控对象校正逆模型的建立相结合,将控制器的自适应过程归结为被控对象校正逆模型的在线辨识问题,通过对校正逆模型的在线辨识直接对改进型增量式控制算法中控制器的参数进行在线修正,形成了一种增量式自适应逆控制系统.将该方法应用于锅炉过热汽温控制系统中,并通过与常规PID串级控制和直接自适应逆控制系统的控制效果对比,验证了所提方法的有效性.     

Quasi-Newton-type optimized iterative learning control for discrete linear time invariant systems

In this paper, a quasi-Newton-type optimized iterative learning control (ILC) algorithm is investigated for a class of discrete linear time-invariant systems. The proposed learning algorithm is to update the learning gain matrix by a quasi-Newton-type matrix instead of the inversion of the plant. By means of the mathematical inductive method, the monotone convergence of the proposed algorithm is analyzed, which shows that the tracking error monotonously converges to zero after a finite number of iterations. Compared with the existing optimized ILC algorithms, due to the superlinear convergence of quasi-Newton method, the proposed learning law operates with a faster convergent rate and is robust to the ill-condition of the system model, and thus owns a wide range of applications. Numerical simulations demonstrate the validity and effectiveness.     

三平移并联机器人控制算法

论文对一种三平移并联机器人进行了运动学建模,运用矩阵计算方法得到其机构运动学反解,即根据终端执行器的运动规律,求出原动件在单位时间内的位移,进而求得步进电机在单位时间内所发的脉冲数。实验验证该步进电机控制算法的正确性,为并联机器人的运动控制提供了理论方法。     

重庆羊角滑坡群滑带土抗剪强度研究

羊角滑坡群是乌江白马航电枢纽坝前的一个巨型滑坡群,该滑坡群的稳定与否,对白马航电枢纽的安全运行至关重要.为能给该滑坡群的治理工程设计和稳定分析提供准确的强度参数,对该滑坡群中各滑坡的滑带土抗剪强度进行研究.采用滑带土室内试验、现场大剪试验、反演分析等方法,确定了羊角滑坡群各滑带土的抗剪强度参数,为工程设计提供了可靠的数...     

Pulse-order recursive method for inverse covariance matrix computation applied to space-time adaptive processing

The conventional space-time adaptive processing(STAP) method such as the typical sample matrix inversion(SMI)-based STAP method is difficult to implement for a practical system because intense computational complexity arises in calculating the inversion of a space-time covariance matrix directly.According to the block Hermitian matrix property of space-time covariance matrix,a new pulse-order recursive method is proposed in this paper to calculate the inverse covariance matrix for the STAP adaptive weight,which can reduce the computational complexity significantly.The proposed method requires initially calculating the inverse covariance matrix of the first pulse-order recursively based on the block Hermitian matrix property.In the following,the inversion of space-time covariance matrix is obtained recursively based on the previous pulse-order inverse covariance matrix.Next,the STAP adaptive weight is calculated based on the inversion space-time covariance matrix previously obtained.Compared with the conventional SMI-based STAP algorithms,the computational complexity of the proposed method is reduced to more than 50% for the same clutter suppression performance.This method can be applied to practical systems benefiting from small computational complexity and stable clutter suppression performance.     

基于双目视觉的机器人目标定位与机械臂控制

为了更好地与复杂多变的非结构化环境进行交互,完成对目标物体的识别和抓取,提出了一种应用于服务机器人平台的基于双目视觉的仿人机械臂控制方法.文中首先用D-H方法对机械臂进行建模,并对这个模型做了改进,给出了一种更加简便的3+1自由度仿人机械臂的逆解算法,采用基于双目视觉与颜色分割的目标识别方法;然后根据识别出的目标三维坐标信息控制机械臂完成抓取任务;最后,本方法在家庭服务机器人上得到了验证,机器人能够完成对目标物体的识别和抓取动作.     

Application of parallel mechanism in varistructured quadruped/biped human-carrying walking chair robot

For the existing problems of walking chair robot such as simple function,lower bearing capacity and not walking in complex environment,a novel varistructured quadruped / biped human-carrying walking chair robot is proposed.The proposed robot could be used as biped and quadruped walking chair robots.Considering the conversion of the walking chair robot from the quadruped to the biped or vice versa,6-UPS and 2-UPS+UP(U,P and S are universal joint,the prismatic pair,and sphere joint,respectively) parallel mechanisms are selected as the leg mechanism of the biped walking robot and quadruped walking robot,respectively.Combining the screw theory and theory of mechanism,the degrees of freedom of the leg mechanism and the body mechanism in diferent motion states are computed so as to meet the requirements of mechanism design.The motion characteristics of the 2-UPS+UP parallel mechanism which is the key part of the walking chair robot are analyzed.Then,the workspace of the moving platform is drawn and the efect of the structural parameters on the workspace volume is studied.Finally,it is found that the volume of the workspace of the moving platform is bigger when the side length ratio and the vertex angle ratio of the fxed platform and the moving platform which are isosceles triangles are close to 1.This study provides a theoretical foundation for the prototype development.     

Development of wheel-less snake robot with two distinct gaits and gait transition capability

Snake robots are mostly designed based on single mode locomotion. However, single mode gait most likely could not work effectively when the robot is subject to an unstructured working environment with different measures of terrain complexity. As a solution, mixed mode locomotion is proposed in this paper by synchronizing two types of gaits known as serpentine and wriggler gaits used for non-constricted and narrow space environments, respectively, but for straight line locomotion only. A gait transition algorithm is developed to efficiently change the gait from one to another. This study includes the investigation on kinematics analysis followed by dynamics analysis while considering related structural constraints for both gaits. The approach utilizes the speed of the serpentine gait for open area locomotion and exploits the narrow space access capability of the wriggler gait. Hence, it can increase motion flexibility in view of the fact that the robot is able to change its mode of locomotion according to the working environment.     

电子步道在步态时空参数测量中的可靠性

评估电子步道在步行运动学参数采集中的可靠性.37名男性志愿者参与到实验中,年龄在21岁到32岁之间,所有受测者都是健康的个体.在实验中,分别以自选的慢走、正常走和快走三个模式采集步行中的步长、步频和步速.研究结果显示电子步道在测量步态时空参数时具有很高的可靠性,还展示了可靠系数分别达到0.75和0.9所需的测试次数.当利用电子步道采集不同速度模式下的步态参数用于实验研究时(可靠系数大于0.9),至少需要3次测量.     

Optimal Trajectory Planning for Wheeled Mobile Robots Based on Kinematics Singularity

This research introduces a new optimality criterion for motion planning of wheeled mobile robots based on a cost index that assesses the nearness to singularity of forward and inverse kinematic models. Slip motions, infinite estimation error and impossible control actions are avoided escaping from singularities. In addition, high amplification of wheel velocity errors and high wheel velocity values are also avoided by moving far from the singularity. The proposed cost index can be used directly to complement path-planning and motion-planning techniques (e.g. tree graphs, roadmaps, etc.) in order to select the optimal collision-free path or trajectory among several possible solutions. To illustrate the applications of the proposed approach, an industrial forklift, equivalent to a tricycle-like mobile robot, is considered in a simulated environment. In particular, several results are validated for the proposed optimality criterion, which are extensively compared to those obtained with other classical optimality criteria, such as shortest-path, time-optimal and minimum-energy.