摘要
并联机床又称并联结构机床、虚拟轴机床。并联机床是基于空间并联机构Stewart平台原理开发的,是并联机器人机构与机床结合的产物,是空间机构学、机械制造、控制技术、计算机软硬件技术和CAD/CAM技术高度结合的高科技产品。论文做的主要工作包括以下几个方面:
针对六自由度并联机床,首先在Matlab软件中建立其逆解数学模型,即定义其动坐标系和定坐标系,运动副的类型,动平台和和定平台等各个构件的空间位置。然后通过欧拉角坐标变换法求其数学模型,得到用于控制刀具运动轨迹的杆长变化函数。
在完成运动学逆解分析之后,在UG软件中建立其三维模型,并将模型导入ADAMS软件中对其进行运动学仿真,得到杆件的运动仿真曲线,通过与MATLAB求解获得的理论曲线相比较,结果是吻合的,从而验证了逆解模型的正确性,为进一步在开放式数控系统的运动模块中建立逆解模型奠定了基础。
为实现对六自由度并联机床的运动控制,本文提出以EMC2(Enhanced Machine Controller,增强的机器控制器)开放式数控系统为平台建立并联机床的控制系统。本文运用求得的逆解模型,在EMC2中重新建立其运动学逆解模块,并用数控加工实例加以仿真验证,得到了正确的结果,从而证明了所提方法的可行性,为本课题项目后续的样机制造及电机输出控制奠定了重要基础。
Parallel Machine Tools is also called Parallel Structured Machine Tools, Virtual Axis Machine Tools. Parallel machine tools is developed basing on principle of spatial parallel-mechanisms Stewart platform, which is the product of Parallel Robotic Mechanisms and machine tools. And parallel machine tools is high-tech products of powerful mixture of spatial machanisms, Mechanical Manufacturing, control technique, computer soft-hard wares technology and CAD/CAM technology. The paper is focused on the following pionts:
This paper analyzes 6-DOF parallel kinematic machine(PKM) kinematics character, solves its inverse model via MATLAB software. In this step, it needs to define the mobile and base coordinate system, the type of the movement and the LOCA of the base and mobile platform and all of the structual members. The mathematic model which used to control toolpath is completely ascertained with the method of Euler parameter transformation.
After the analysis of the kinematics inverse transformation, this paper constructs PKM model under UG environment. Kinematics simulation is performed through introducing the model into ADAMS, finally rod kinematic simualtion curve is obtained. By comparing simulation curve with the theoretical one obtained from MATLAB, the curves match each other well, which demonstrates the correctness of the inverse model. Therefore, the inverse mathematics model in Open Numerical Control System kinematics module is set up.
To realize motion control of 6-DOF PKM, this paper provides a way of applying EMC2(Enhanced Machine Controller) Open Numerical Control System as the platform to build PKM’s control system. In this paper, the obtained inverse model is used, and the kinematics inverse module is rebuilt in EMC2 and verified by simulation with CNC code, which lays an important foundation for later prototype construction and motor output control.
引文
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