【作者】 姜昆鹏；

【导师】 杨超君；

【作者基本信息】 江苏大学 ， 机械设计及理论， 2016， 硕士

【摘要】 并联机构因具有结构简单、负载能力强等优点,被广泛用于汽车模拟驾驶、并联机床、飞行模拟器等诸多领域。随着我国农业机械的飞速发展,将并联机构应用于田间路谱信息的复现,并将得到的路谱信息用于农用设备的颠簸试验中,将成为新的研究热点。本文在确定机构的驱动方式之后,完成驱动系统各零件关键参数的计算选型;针对选用的阀控缸系统传递函数进一步完善,并对空间运动相关问题进行研究;在仿真过程中采用控制与鲁棒控制两种控制策略进行效果对比。(1)系统地介绍了并联机构的结构特征与工作原理,阐述了液压控制系统作为并联机构驱动系统的主要优势,并按照设计手册针对液压控制系统中液压缸有杆腔、无杆腔的直径尺寸及泵的功率等关键部件、关键参数进行详细计算。运用空间运动相关理论研究了空间坐标系的变换规律,完成机构空间运动的运动位置正反解、雅克比矩阵的求解以及速度分析,进行了机构运动中的奇异性分析与雅克比矩阵条件数分析。(2)在液压缸伸缩杆伸长过程中,通过分析,提出将选用的伺服阀阀芯位移与输入电流之间的传递函数综合到阀控缸系统中非对称液压缸伸缩杆位移与伺服阀阀芯位移之间的传递函数中;将伺服阀输出负载流量与输入电流之间的传递函数综合到非对称液压缸伸缩杆位移与无杆腔输入流量之间的传递函数中,并分别引入高分辨率反馈装置,建立两种液压缸伸缩杆伸长位移与伺服阀输入电流之间的传递函数,完善了并联机构的液压控制系统的数学模型,并提出了一种田间路谱信息复现的控制算法的实现方案。(3)运用三维软件!"对并联机构进行零部件建模以及整体模型装配,通过软件间的转换接口将三维模型导入运动学模拟软件##$中,通过机构的自由度计算与软件的自我分析,验证了模型的正确性,同时使其在六个空间自由度方向运动,完成运动学正、反解仿真;运用#$%$液压仿真软件建立了液压伺服控制回路的模型,分析了控制与鲁棒控制器两种控制策略的工作原理,并提出将控制与鲁棒控制器并联设计进行系统仿真,对比分析不同频率下两种控制方案的优劣。(4)运用伺服阀静态性能测试系统对液压控制系统中所选用的伺服阀进行静态性能检测,得到其静态性能曲线,进行伺服阀静态性能参数的计算,并与样本数据进行对比,分析其工作可靠性;对并联机构进行相应的正反解试验,并对其数据结果进行分析对比,提出进一步的改进研究工作。更多还原

【Abstract】 Stewart parallel mechanism has become a hotspot in the field of robotics because of its high rigidity, simple structure, strong load capacity and other advantages. Stewart parallel mechanism is widely used in automobile driving simulation system of parallel machine tools, flight simulator and other fields. With the emphasis on agricultural development of our country, the Stewart parallel mechanism is also used in the field of the recurrence of road spectrum information and the bump test on farm equipment by the road spectrum information. The calculation and selection of the parts of the driving system In this paper are made after determining the drive mood. The transfer function of the system of the cylinder controlled by valve is made to further improve. The effects of the two control strategies of PID control method and H∞ robust control method are compared in the simulation process. According to the domestic and foreign development trend, application fields and research methods, the main content put forward in this paper is as follow:(1) The system structure and working principle of Stewart parallel mechanism are introduced. The main advantages of hydraulic control system are elaborated as the drive system of the Stewart parallel mechanism; The calculation and selection of the key components in the hydraulic control system are also introduces, including the hydraulic valve, the hydraulic cylinder and so on. Combined with the knowledge of spatial mechanism, the transformation rule of spatial coordinates is introduced and the forward and inverse solution of position, solution of Jacobian matrix and velocity analysis are all accomplishd. The operation mechanism in the singularity and the condition number of Jacobian matrix are all calculated.(2) After analyzing the transfer function between the displacement of the valve core and the extension displacement of the telescopic rod in the system of cylinder controlled by valve, the mathematical model of the hydraulic control system of the Stewart parallel mechanism is deducted by adding the transfer function between the displacement of the valve spool and the input current; After analyzing the transfer function between the input flow of the cavity without rod and the extension displacement of the telescopic rod in the system of cylinder controlled by valve, the mathematical model of the hydraulic control system of the Stewart parallel mechanism is deducted by adding the transfer function between the output flow of valve and the input current. Based on the two methods, the high-resolution feedback device is proposed to analysis and optimize hydraulic control system; The control algorithm for the reproduction of road spectrum information is proposed.(3) Three-dimensional software Solidworks is used to build the model and assemble the model of the whole Stewart parallel mechanism. The three-dimensional model is imported into the kinematics simulation software ADAMS through the conversion interface between the software. The positive and inverse kinematics simulation is carried out to verify the correctness of the model. The working principle and the ideal effect of two the control strategy(PID control and H∞ robust control) are analyzed. The hydraulic simulation software AMESIM is used to carry out the loop modeling according to the hydraulic control system. The results are compared and analyzed through the parallel connection of PID control and H∞ robust control in the system simulation. The advantages and disadvantages of the two control schemes are compared and analyzed, and the related ideas are put forward in the following research.(4) Servo valve static characteristic test system is used to test the static performance of the selected chosen servo valve of the hydraulic control system and its static performance curves of the servo valve are obtained. Then the performance parameters are calculated and compared with the sample data. The corresponding positive and inverse solutions of the Stewart parallel mechanism are tested, and the results are analyzed and compared. And the further research work is put forward.更多还原