四索驱动并联机构控制系统设计与轨迹跟踪实验研究

发布时间：2019-04-03 06:37

【摘要】：索驱动并联机构是由柔索替代传统刚性杆的一种新型并联机构,其结构简单、承载能力强、工作空间灵活、易于实现,在实际工程中得到了广泛应用。索驱动并联机构的出现是并联机构家族中的一次重要补充,极大地拓展了并联机构的应用领域,但其控制方法和控制精度仍是限制索驱动并联机构在各个行业推广应用的重要因素。本文主要研究内容包括:构建了四索驱动并联机构的运动学正、逆解数学模型,仿真验证了正、逆解算法的有效性;基于拉格朗日法建立了其动力学模型,为机构的控制系统设计奠定了模型基础。针对索驱动并联机构的非线性、强耦合、多输入多输出等特点,设计了强鲁棒性和抗干扰性的自抗扰控制器。仿真分析显示该控制器可以实现四索驱动并联机构高精度的轨迹控制。完成了以工业PC和DMC运动控制卡为核心的开放式数控系统的软硬件设计。在硬件上,选用了 NC嵌入PC方式的主从式控制结构,并通过DMC提供的接口函数实现了运动控制卡与伺服驱动之间的连接;在软件上,基于Visual C++完成了四索驱动并联机构的专用控制界面和通用G代码控制界面的软件开发。基于非线性最小二乘法完成了四索驱动并联机构初始零点的标定;预测了运动学参数误差对运动精度的影响趋势;确定了轨迹跟踪实验的插补点数和脉冲指令等控制参数,进而实现了直线和圆弧轨迹跟踪的稳定控制。
[Abstract]:Cable-driven parallel mechanism is a new type of parallel mechanism, which replaces the traditional rigid bar by flexible cable. Its structure is simple, its bearing capacity is strong, its workspace is flexible, and it is easy to be realized. It has been widely used in practical engineering. The emergence of cable-driven parallel mechanism is an important supplement in the family of parallel mechanism, which greatly expands the application field of parallel mechanism. However, its control method and control precision are still important factors that limit the popularization and application of cable-driven parallel mechanism in various industries. The main contents of this paper are as follows: the forward and inverse kinematics model of the four-cable-driven parallel mechanism is constructed, and the validity of the forward and inverse solution algorithm is verified by simulation; The dynamic model is established based on Lagrangian method, which lays a foundation for the design of the control system of the mechanism. Aiming at the nonlinear, strong coupling and multi-input multi-output characteristics of cable-driven parallel mechanism, an active disturbance rejection controller with strong robustness and anti-interference is designed. Simulation analysis shows that the controller can achieve high-precision trajectory control of four-cable drive parallel mechanism. The software and hardware design of the open CNC system based on industrial PC and DMC motion control card is completed. In hardware, the master-slave control structure with NC embedded in PC mode is selected, and the connection between motion control card and servo driver is realized through the interface function provided by DMC. In the software, the special control interface and the general G code control interface of the four-cable drive parallel mechanism are developed based on Visual C. Based on the nonlinear least square method, the calibration of the initial zero point of the four-cable drive parallel mechanism is completed, and the influence trend of the kinematic parameter error on the motion accuracy is predicted. The control parameters, such as interpolation number and pulse instruction, are determined in the trajectory tracking experiment, and then the stable control of linear and circular trajectory tracking is realized.
【学位授予单位】：西安理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP242

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