Application of Soft Actuation to Bilateral Control and Haptic Reproduction

International Journal of Control, Automation and Systems - The main research topic of this paper is to apply the sliding mode based soft actuation to smooth transition between position, force, and...     

Controlled Thermophoresis as an Actuation Mechanism for Noncantilevered MEMS Devices

A microelectromechanical system actuator based on thermophoretic, or Knudson, forces is proposed using analytical calculations. It can potentially execute scanning or spinning motions of a body that is not mechanically attached to the reference substrate. For a silicon device of 100-$muhbox{m}$ diameter, it is calculated that it can be levitated at a distance of about 0.5 $muhbox{m}$ from a substrate and that it can execute scanning motion and use quasi-springs by laterally acting thermal forces. In this way, an engine with spinning motion of a floating body having a diameter of 200 $muhbox{m}$ with up to 5 kHz can be achieved.$hfill$[2008-0013]      

LPV Modeling and Tracking Control of Dissimilar Redundant Actuation System for Civil Aircraft

International Journal of Control, Automation and Systems - Dissimilar redundant actuation systems (DRAS) are in practice in advanced aircraft in order to increase reliability and to resolve the...     

Dynamics and Control of Elastic Joint Manipulators

The investigations presented in this paper are based on our previousstudies where the modeling and control problems of rigid body manipulatorswere treated through the so-called vector-parametrization of the SO(3)group. The nice property of this parametrization, which also displays a Liegroup structure, is that it drastically simplifies some considerations andreduces the computational burden in solving direct kinematic problems,inverse kinematic problems and dynamic modeling by more than 30 hitherto.This statement, which is valid for models built through vector-parameter,becomes stronger in pure vector-parameter considerations. It is provedadditionally that the computational effectiveness of the vector-parameterapproach increases with the increasing number of the revolute degrees offreedom. Here we show that this can be used successfully in the problems ofelastic joint manipulators where, besides the real n links,nfictious links are included and an additional nrevolute degrees of freedom are involved. The present paper also considersthe role of group representations of the rotation motions in the modelingand control of manipulators with elastic joints. Dynamic modelsthrough vector-parameter and in purevector-parameter form are developed and the inverse dynamic problem isdiscussed. It is shown that the nonlinear equations of motion are globallylinearizable by smooth invertible coordinate transformation and nonlinear state feedback.     

Bio-Inspired Actuation and Sensing

The superb ability of animals to negotiate rough terrain has caused engineers to focus on mechanical properties of muscle and other unique features in order to design improved robots for exploration. This paper reviews recent work in artificial muscle actuators, as well as a new sensor based on a robotic model of the muscle spindle cell. The actuator contains a pneumatic force generator in parallel with a non-linear damping element and in series with a non-linear elastic tendon. Work loop experiments were performed to characterize this actuator under conditions similar to real locomotion at different speeds. The robotic muscle spindle is an 8 × 1 cm device which simulates the response of the physiological muscle spindle to stretch. Its non-linear properties are thought to contribute to stable accurate control over a wide range of motion.     

基于PLC技术的机电设备作动系统协调控制仿真

传统方法在进行机电设备作动系统调控时,存在协调控制误差较大,执行效率差等问题.结合PLC技术,提出一种机电设备作动系统协调控制方法.结合PLC技术中的Petri网法,组建Petri网控制模型;分析Petri网控制模型和梯形图之间的转换关系,完成机电设备作动系统的Petri网建模.将控制模型转换为PLC协调控制程序,以达到机电设备作动系统协调控制的目的.为验证提出方法的有效性,设计对比实验.结果表明,所提方法能够有效降低机电设备作动系统协调控制误差,同时增强系统的执行效率.     

基于MDP支持弹性服务质量的接入控制

在网络服务系统中,满足业务请求的服务质量需求是系统要解决的主要问题之一。接入控制方法和资源分配策略常用来保证业务的服务质量要求。本文基于Markov决策过程(MDP)对视频点播(VOD)系统进行建模,同时考虑了弹性服务质量这一机制。弹性服务质量可以用一个QoS的需求范围来体现。策略梯度算法常用来解决MDP问题,它能够以比较好的速度收敛到最优解。通过算法实例对本文的接入控制方法进行性能分析,发现所采用的方法相对于一般的完全接入策略具有较优的性能。     

航天器姿轨耦合非线性同步控制

研究航天器飞行稳定控制建模问题。航天器动力学模型的精确建立,要求采用单独建立轨道或姿态的模型无法满足任务高精度要求,从非线性相对轨道动力学方程和修正罗德里格斯参数(MRP)表示的姿态运动学方程出发,建立了航天器六自由度的相对耦合动力学方程。为了给出姿轨运动的基准,分别设计了航天器理想姿态和椭圆加指数接近轨道。针对耦合非线性动力学方程设计了非线性同步控制律,并通过Lyapunov证明闭环系统的全局渐近稳定性。通过仿真结果可以看出,非线性同步控制算法能使轨道和姿态误差逐步趋于零,为航天器姿轨耦合设计提供了依据。     

二维Logistic映射分岔控制

利用系统的状态反馈和参数调节方法,精确控制了二维Logistic映射发生第一、二次分岔时分岔点位置,从而在不改变系统原来分岔特性的基础上,只需选择合适的调控参数,就可实现二维Logistic映射的混沌控制和反控制.     

Coupled Oscillator Control of Autonomous Mobile Robots

This paper introduces a nonlinear oscillator scheme to control autonomous mobile robots. The method is based on observations of a successful control mechanism used in nature, the Central Pattern Generator. Simulations were used to assess the performance of oscillator controller when used to implement several behaviors in an autonomous robot operating in a closed arena. A sequence of basic behaviors (random wandering, obstacle avoidance and light following) was coordinated in the robot to produce the higher behavior of foraging for light. The controller is explored in simulations and tests on physical robots. It is shown that the oscillator—based controller outperforms a reactive controller in the tasks of exploring an arena with irregular walls and in searching for light.     

Robust Neural Network Motion Tracking Control of Piezoelectric Actuation Systems for Micro/Nanomanipulation

This paper presents a robust neural network motion tracking control methodology for piezoelectric actuation systems employed in micro/nanomanipulation. This control methodology is proposed for tracking of desired motion trajectories in the presence of unknown system parameters, nonlinearities including the hysteresis effect and external disturbances in the control systems. In this paper, the related control issues are investigated, and a control methodology is established including the neural networks and a sliding control scheme. In particular, the radial basis function (RBF) neural networks are chosen for function approximations. The stability of the closed-loop system, as well as the convergence of the position and velocity tracking errors to zero, is assured by the control methodology in the presence of the aforementioned conditions. An offline learning procedure is also proposed for the improvement of the motion tracking performance. Precise tracking results of the proposed control methodology for a desired motion trajectory are demonstrated in the experimental study. With such a motion tracking capability, the proposed control methodology promises the realization of high-performance piezoelectric actuated micro/nanomanipulation systems.      

Elastic Curves as Solutions of Riemannian and Sub-Riemannian Control Problems

We consider the nonlinear dynamic interpolation problem on Riemannian manifolds and, in particular, on connected and compact Lie groups. Basically we force the dynamic variables of a control system to pass through specific points in the configuration space, while minimizing a certain energy function, by a suitable choice of the controls. The energy function we consider depends on the velocity and acceleration along trajectories. The solution curves can be seen as generalizations of the classical splines in tension for the Euclidean space. The relations with sub-Riemannian optimal control problems are explained. Date received: June 2, 1999. Date revised: November 25, 1999.     

基于PCC的弹性扭转系统控制器能设计与实现

贝加莱（B＆R）公司将工业中柔性连接驱动加以抽象,设计开发出了一套多质量弹性扭矩装置,其具有强震荡性,依据对象特性,本文采用双微分反馈（DDF）控制方案,征B＆R公司的X20控制器上开发相应模块,用C语言编写了控制程序,实验结果表明该控制方案能使系统往极短的时间内达到预设速度,实现了无超调的控制效果,并具有较高的稳态精度。将双轮负载扩展为三轮负载后,微调控制器参数仍可得到理想的控制效果,体现了控制系统县有良好的鲁棒性,控制器具有优秀的控制性能。     

On Impulsive Synchronization Control for Coupled Inertial Neural Networks with Pinning Control

Neural Processing Letters - The impulsive control for the synchronization problem of coupled inertial neural networks involved distributed-delay coupling is investigated in the present paper. A...     

三箱耦合液位控制网络实验系统

三箱耦合液位控制系统是自动控制教学中非常重要的设备。文章讲述了远程实现液位控制实验的具体结构和实现方法。该系统应用Internet、自动控制、面向对象编程及数据库等技术,使学生能够远程登录该系统进行液位控制实验设计,并通过Internet运行实验得到结果。系统设计充分考虑了系统的高效性、可靠性和友好性,控制端内置的PID控制算法不仅为用户设计自己的控制器提供了很好的范例,还方便用户比较不同的PID自整定方法,并为用户提供了C语言的标准二次开发接口,方便用户对自己的算法进行验证。     

Control of Robots with Elastic Joints Interacting with Dynamic Environment

In this paper, the control of robots with elastic joints in contact with dynamic environment is considered. It is shown how control laws synthesized for the robots with rigid joints interacting with dynamic environment can also be used in the case of robots with elastic joints. The proposed control laws are based on a robot model interacting with dynamic environment, including the dynamics of actuators and the elasticity of joints. The proposed control laws possess two feedback loops: the outer, serving for on-line calculation of the motor shaft angle based on the position error or the contact force error, and the inner one, serving for performing stabilization around the calculated motor shaft angle. Simulation results which exhibit the application of the appropriate control laws are also presented.     

基于VRML和JavaScript的动画控制机制

VRML(Virtual Reality Modeling Language)是一种用在Internet和Web超链接上的多用户交互的、独立于计算机平台的网络虚拟现实建模语言。目前基于VRML的虚拟现实动画仿真控制机制都是采用通用3D软件或Flash制作的,这种机制在场景实体较少或控制逻辑简单时是可行的,但对于虚拟场景实体较多且控制逻辑复杂的情况,会导致场景抖动、程序运行缓慢、灵活性不足以及程序过大。就上述问题,使用VRML与JavaScript结合的方法利用JavaScript构建仿真器直接驱动VRML场景,研究了实验过程的仿真控制,解决了场景抖动、程序运行缓慢、灵活性不足以及程序过大等情况,使仿真过程能够平稳、正确地运行。     

Distributed Control of Multi-Robot Systems Engaged in Tightly Coupled Tasks

NASA mission concepts for the upcoming decades of this century include exploration of sites such as steep cliff faces on Mars, as well as infrastructure deployment for a sustained robotic/manned presence on planetary and/or the lunar surface. Single robotic platforms, such as the Sojourner rover successfully flown in 1997 and the Mars Exploration Rovers (MER) which landed on Mars in January of 2004, have neither the autonomy, mobility, nor manipulation capabilities for such ambitious undertakings. One possible approach to these future missions is the fielding of cooperative multi-robot systems that have the required onboard control algorithms to more or less autonomously perform tightly coordinated tasks. These control algorithms must operate under the constrained mass, volume, processing, and communication conditions that are present on NASA planetary surface rover systems. In this paper, we describe the design and implementation of distributed control algorithms that build on our earlier development of an enabling architecture called CAMPOUT (Control Architecture for Multi-robot Planetary Outposts). We also report on some ongoing physical experiments in tightly coupled distributed control at the Jet Propulsion Lab in Pasadena, CA where in the first study two rovers acquire and carry an extended payload over uneven, natural terrain, and in the second three rovers form a team for cliff access.