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开放式机器人控制器及相关技术研究
Research on Techniques of Open Architecture Robot Controller
【作者】 潘炼东;
【导师】 黄心汉;
【作者基本信息】 华中科技大学 , 控制理论与控制工程, 2007, 博士
【摘要】 大多数现有的工业机器人都使用专用的控制器。非标准的硬件接口、自定义的通信协议以及编程语言使得对硬件和软件的改变都非常困难。这种封闭式的结构限制了机器人适用范围,同时也不利于机器人的研究和产业化。因此,研究具有开放式结构的机器人控制器已成为机器人技术中的一个重要方向。本文以通用5自由度连杆机器人为研究对象,对机器人开放式控制器的实现中所涉及的硬件构成、软件平台以及控制技术等相关问题进行了研究。通过对开放式机器人控制的概念和发展趋势的讨论,指出了实现开放式控制器的一条有效途径是:充分利用标准的软硬件技术,按照基于接口的,模块化的原则为机器人控制器提供可组装的模块。针对机器人系统的特点,提出了基于组件技术的机器人功能组件模型,并对机器人控制器的功能结构和功能组件的实现方式进行了分析。讨论了开放式机器人控制的实时性问题,采用在通用操作系统上加入实时扩展的方式为控制器提供实时支持,在此平台上,对开放式机器人控制器中的组件通信机制、连接配置和运行调度进行了详细的分析。为了获得开放式控制器的实验平台,对Movemaster-EX RMV1型机器人原有控制器及其运动学特性进行了详细分析,提出了基于PC+DSP的硬件改造方案,并对改造中所涉及到的接口和驱动实现进行了说明。讨论了基于DSP的多轴运动控制器在开放式机器人控制器实现中的作用,并提出了具有开放特性的多轴运动控制器的设计方案。分析了直流电机驱动的机器人关节的控制模型,提出了一种适于数字实现的在线关节重力补偿算法,可有效提高关节控制的性能。在机器人的开放式平台上,实现了一个离线编程系统的基本雏形,重点讨论了三维造型和碰撞检测问题。应用面向对象的方法对机器人结构进行分解,通过交互式的输入和选择,可以快速建立起机器人及其环境的三维模型。在碰撞检测中,运用基于Voronoi空间的距离计算方法,实现了快速的干涉判断。另外还对传感器的仿真和机器人的编程问题进行了研究,给出了视觉仿真的初步实现。为了满足开放式机器人控制器对传感器集成的需要,提出了基于三层组件结构的多传感器集成方法。对基于规划和基于行为的控制方式的特点进行了分析,提出了多传感器机器人的集成控制结构,该结构充分考虑了感知和控制两方面的需要,并将规划和反应式行为控制有机的组合在一起。采用这种控制结构实现了一个实验系统,用于完成简单的装配任务,机器人在完成规划目标的同时,能实时地响应外部环境的变化。
【Abstract】 Most of the conventional robot controllers are designed with closed natures, such as non-standard hardware interface, customized communication protocol and special program language. It is difficult and expensive to modify a closed controller to integrate external hardware and software. The closed controller architecture is lacking in flexibility and imposes disadvantageous effect on robotic industry and research. This has led to the demand for controllers based on open architecture. This dissertation mainly aims to implement an open architecture robot controller. Some relative fields are researched, including hardware structure, software platform and control technology.An approach has been proved to be effective in designing the open architecture controller. This is that an open architecture controller should be constructed by interface-based modular models designed in defacto standard hardware and software techniques. According to this principle, we propose the functional component model of robot. By using this model, the functional architecture of a robot controller is analyzed. The real time performance of the controller is also considered. A real time extension is added on the general OS to support the real time operations. Based on this OS platform, the communication mechanism, configurable connection and run-time schedule of the components in an open architecture controller are researched.To implement the open architecture controller, a Movemaster-EX RMV1 type robot is used as an experiment platform. The old proprietary controller and kinematics of the robot are analyzed. And then a PC+DSP scheme is proposed to modify the hardware structure. Some details of the interface and driver are described. A design scheme of DSP based multi-axis motion controller is presented. And its open characteristics are discussed also. To improve the performance of joint control, an on-line gravity compensation algorithm is designed and applied to the joints drove by DC motors.A basic off-line program subsystem is realized based on the open architecture. The 3D modeling and collision detection are two emphases. With the object-oriented method, graphical user interfaces are designed to support the fast 3D modeling of robot by simple menu operations. On collision detection, the distance computation algorithm base on Voronoi space is exploited to make a quick interference judgment. Sensor simulation and robot program are also considered in this subsystem. And a theoretical implementation of vision simulation is presented.A three-tier architecture is presented to integrate multi-sensor in the open robot controller. Exploiting this integration method and considering the essence of deliberative /reactive control approaches, an integrated control architecture for multi-sensor robot is proposed. This architecture ensures that the robot can adapt to environment changes while achieving the planned goal. An experimental system according to this architecture is constructed.
【Key words】 Open architecture controller; Component technology; Motion control; Robotic simulation; Multi-sensor integration;