人体运动捕捉及运动控制的研究

在论述了几种方式的人体运动捕捉的基础上,介绍了光学运动捕捉的关键技术,包括摄像机标定、标记点跟踪和三维重建技术。无标记点的运动捕捉是新兴的技术,它将捕获的图像进行分割并分析,然后用多种约束算法进行三维重建。基于运动捕捉的人体运动控制相关文献很少,文中列举了现有各种应用运动捕捉数据的方式,包括基于关键帧、运动学和物理模型等的应用。论文对运动捕捉及运动控制技术进行了总结,可为此领域的研究提供有用的信息。     

Suboptimal Control of Rigid Body Motion with a Quadratic Cost

In this paper we consider the problem of controlling the rotational motion of a rigid body using three independent control torques. Given a quadratic cost we seek stabilizing state feedback controllers which guarantee that all motions starting within a specified bounded set have cost less than a given number; i.e., we seek suboptimal stabilizing controllers. For a special class of cost functions, we present explicit expressions for suboptimal stabilizing controllers yielding a cost arbitrarily close to the infimal cost. For the general case, we present sufficient conditions which guarantee the existence of linear, suboptimal, stabilizing controllers.     

多智能体沿多条给定路径编队运动的有向协同控制

研究了在有向通信连接下二阶积分器描述的多智能体沿多条给定路径编队运动的控制器设计及其稳定性分析问题. 智能体的动态和指定路径都是在固定直角坐标系下描述的. 通过引入路径函数来设计路径跟踪控制, 根据路径函数与弧长的关系来设计编队控制律, 使得多智能体沿期望路径的位置和速度在规定队形下达到一致. 利用图论证明, 当通信拓扑对应的有向图具有全局可达点时, 设计的编队控制系统是渐近稳定的. 本文设计的有向协同控制律可以应用于区域的信息优化采集.     

Numerical Simulation of Oldroyd-B Fluid in a Contraction Channel

A spectral element method coupled with the elastic viscous split stress technique for computing viscoelastic flows is presented. The rate of deformation tensor is introduced as an additional variable in the momentum equation, but not in the constitutive equation. The nonlinear rheological model, Oldroyd-B, is chosen to simulate the flow of a viscoelastic fluid. Numerical solutions are investigated based on a planar 4:1 abrupt contraction channel flow benchmark problem with different Weissenberg numbers. The results show a good agreement with other numerical predictions.     

Control of Motion of an Actively Bending Body in Channels with Dry Friction

Mechanics is described and equations are given of the motion of an actively bending homogeneous body of a finite thickness in a channel with dry friction under conditions of a weak bending. Control is suggested of the motion of a body in a sinusoidal channel, which retains a continuous first derivative of the controlling moment and a bounded second derivative. A process is described of the maximization of the speed of motion by control and then by the choice of the best parameters of a channel. Control is also considered of other modes of the motion of a body in the same channel.     

编队控制中的机器人行为与基于服务的运动行为结构设计

以基于位姿误差的虚拟目标跟踪为控制模式,提出了独立于编队控制与协作任务,但却适用于多移动机器人编队运动的基于服务的机器人运动行为结构,并对其基本运动行为与选择方法进行了设计.提出的基于服务的机器人行为结构借鉴了软件工程领域的面向服务的架构思想,具有可重用性.多机器人编队形成、改变等仿真与实验验证了本文所提方法的有效性.     

基于多机器人的运动控制平台在刚体对接系统中的应用

针对刚体对接系统,引入虚拟分段概念,分段位姿测量技术．在统一的世界坐标框架内,建立了平台的运动学模型,导出了多机器人的协调运动方案．该方案在基于多机器人的运动平台控制中具有广泛的适用性．     

Control of Motion of an Actively Bending Body in Prescribed Channels with Viscous Friction

Mechanics is described and equations are given of motion of an actively bending homogeneous and continuous body of a finite thickness in channels with the viscous friction, using as an example channels in a viscous fluid. Control of motion is suggested, which ensures a maximum speed of the body in a definite channel. Using a sinusoidal channel as an example, the path is described of the repeated maximization of the speed according to the choice of the best parameters of the channel. Control is considered of a wide class other motions of the body.     

Visualizing Human Body Motion Simulations

The simulation of uncontrolled human motion often requires realistic graphics displays. But what can you do if your simulation program has no graphics capabilities?     

Small Vibrations Superimposed on a Prescribed Rigid Body Motion

A method for analysing flexible multibody systems in which theelastic deformations are small is presented. The motion isconsidered a gross non-linear rigid body motion with small linearvibrations superimposed on it. For periodic gross motion, thisresults in a system of rheolinear differential equations for thedeformations with periodic coefficients. The determination of therequired equations with a program for flexible multibody systemsis discussed which calculates, besides the periodic gross motion,the linearized, or variational, equations of motion. Periodicsolutions are determined with a harmonic balance method, whiletransient solutions are obtained by an averaging method. Thestability of the periodic solutions is considered. The procedurehas a high computational efficiency and leads to more insight intothe structure of solutions. The method is applied to a pendulumwith an elliptical motion of its support point, a slider-crankmechanism with flexible connecting rod, a rotor system, and aCardan drive shaft with misalignment.     

A Low Dimensional Fluid Motion Estimator

In this paper we propose a new motion estimator for image sequences depicting fluid flows. The proposed estimator is based on the Helmholtz decomposition of vector fields. This decomposition consists in representing the velocity field as a sum of a divergence free component and a vorticity free component. The objective is to provide a low-dimensional parametric representation of optical flows by depicting them as deformations generated by a reduced number of vortex and source particles. Both components are approximated using a discretization of the vorticity and divergence maps through regularized Dirac measures. The resulting so called irrotational and solenoidal fields consist of linear combinations of basis functions obtained through a convolution product of the Green kernel gradient and the vorticity map or the divergence map respectively. The coefficient values and the basis function parameters are obtained by minimization of a functional relying on an integrated version of mass conservation principle of fluid mechanics. Results are provided on synthetic examples and real world sequences.     

Motion Control of a Golf Swing Robot

In this paper we discuss our simulation and empirical study of a golf swing motion controller for a two-link golf swing robot. We distinguish two variants of the whole golf swing termed as hitting problem and stopping problem. For the hitting problem arising from backswing and downswing, we map the task into the output of a target dynamic system—a harmonic oscillator—under energy control. For the stopping problem that arises from follow-through, we propose a Proportional plus Gravity and Coupling Torque Compensation (PGCTC) feedback controller. Preliminary simulation study shows the proposed controllers solve the hitting problem and the stopping problem respectively. The controllers are implemented on a physical robot. Experimental results indicate the robot is able to perform desired golf swing-backswing, downswing, and follow-through. We also give a preliminary analysis on the proposed method to understand its merits and weaknesses.     

3D Multi‐Agent Formation Control with Rigid Body Maneuvers

In this paper, we propose a control scheme for the formation maneuvering problem of multi‐agent systems where the team of agents can translate and rotate as a virtual rigid body in 3D. Using the single‐integrator model, we formulate the basic control law which is comprised of a formation acquisition term, function of the graph rigidity matrix, and a rigid body maneuvering term. The control is dependent on the relative position of agents that are connected in an infinitesimally and minimally rigid framework in addition to the desired rigid body motion of the formation. To facilitate the design of the rigid body maneuver, one agent in the convex hull of the formation serves as the reference point for the rotation component. A simulation study demonstrates the formation controller.     

运动控制 安全第一

当软件在飞行器、医疗设备、汽车和工业自动化的控制中成为一个重要因素,由编程故障而呈现的危险不容忽视。过去,当你踏上自己汽车的油门踏板,一个杠杆和联接组成的系统,把你的脚直接连接到汽化器。     

Generic Motion Control

2008年,B＆R提出了GMC（Generic Motion Control）这一前瞻性概念,它着眼于建立面向整厂级的运动控制方案,力图使得这个架构能够适应未来市场不断变化的需求和对成本不断增加的压力。     

并联六自由度运动平台控制系统研究

本文介绍了并联六自由度平台的机构特点,同时在对平台总体控制系统简要设计的基础上完成了单杆液压控制系统的建模工作.考虑了无干扰和有干扰的情况下,对系统进行了仿真分析,提出了基于神经网络算法的先进PID控制方案,仿真结果表明该方法具有良好的控制效果,证明了电液位置伺服控制系统设计的正确性,为平台进一步控制奠定了基础.     

一种球形机器人的非线性滑模运动控制

基于非线性滑模控制方法,对一种欠驱动的球形机器人的运动控制问题进行了研究．球形机器人的输入由两个相互正交的力矩组成．在非完整约束的条件下,分别建立球形机器人的运动学和动力学模型,并通过输入变换将动力学模型变换为一个两输入的二阶系统．基于非线性滑模控制方法分别设计了横向姿态控制器和纵向速度控制器,可以保证被控的运动状态收敛到期望的邻域内．仿真和实验结果验证了所建立的动力学模型和控制方法的有效性．     

Motion Control of a Nonholonomic Mobile Manipulator in Task Space

In this paper, the motion control of a mobile manipulator subjected to nonholonomic constraints is investigated. The control objective is to design a computed‐torque controller based on the coupled dynamics of the mobile manipulator. The proposed controller achieves the capability of simultaneous tracking of a reference velocity for the mobile base and a reference trajectory for the end‐effector. The aforementioned reference velocity and trajectory are defined in the task space, such task setting imitates the actual working conditions of a mobile manipulator and thus makes the control problem practical. To solve this tracking problem, a steering velocity is firstly designed based on the first‐order kinematic model of the nonholonomic mobile base via dynamic feedback linearization. The main merit of the proposed steering velocity design is that it directly utilizes the reference velocity set in the task space without requiring the knowledge of a reference orientation. A torque controller is subsequently developed based on a proposed Lyapunov function which explicitly considers the coupled dynamics of the mobile manipulator to ensure the mobile base and end‐effector track the reference velocity and trajectory respectively. This proposed computed‐torque controller is able to realize asymptotic stability of both the base velocity tracking error and the end‐effector motion tracking error. Simulations are conducted to demonstrate the effectiveness of the proposed controller.     

Articulated Body Motion Capture by Stochastic Search

We develop a modified particle filter which is shown to be effective at searching the high-dimensional configuration spaces (c. 30 + dimensions) encountered in visual tracking of articulated body motion. The algorithm uses a continuation principle, based on annealing, to introduce the influence of narrow peaks in the fitness function, gradually. The new algorithm, termed annealed particle filtering, is shown to be capable of recovering full articulated body motion efficiently. A mechanism for achieving a soft partitioning of the search space is described and implemented, and shown to improve the algorithm’s performance. Likewise, the introduction of a crossover operator is shown to improve the effectiveness of the search for kinematic trees (such as a human body). Results are given for a variety of agile motions such as walking, running and jumping.     

基于视频的三维人体运动跟踪

提出一种结合多种图像特征,在多摄像机环境下跟踪人体运动的方法．通过定义人体模型、摄像机投影模型以及相似性度量模型来得到优化框架下的目标函数,并使用牛顿-高斯优化算法对其进行求解．模拟数据和实际数据的实验表明,文中方法比仅仅使用灰度特征,跟踪结果得到了改善,对比实验结果也优于基于概率算法的退火粒子滤波．