【作者】 林盛；

【导师】 贾振元；

【作者基本信息】 大连理工大学 ， 机械电子工程， 2010， 博士

【摘要】 巨型重载操作装备、巨型重载制造装备以及大型掘进装备等重载装备具有大载荷、大惯量、多自由度、多维力位操控等特点。为提高生产效率和材料利用率,减少由于载荷突变或载荷偏置等因素所造成的突发事故,其末端执行机构必须具有力顺应性和位置顺应性,而实时六维大力测量是实现顺应控制和多自由度协调控制的基础。因此,研制用于重载装备实时六维大力测量的六维大力传感器具有十分重要的意义,但多维和大力之间的矛盾使得六维大力传感器的研制十分困难。本论文提出了一种六维大力分载测量方法,并基于该分载测量方法研制了基于Stewart结构的六维大力传感器,为多维大载荷测量的研究提供了一个新的途径和思路。论文针对多维大力测量中多维和大力之间的矛盾,提出了一种基于Stewart结构的六维大力分载测量方法及其传感器,结合Stewart结构力映射矩阵、Stewart结构位姿正解以及深梁单元刚度矩阵,提出了基于Stewart结构六维大力传感器的力映射矩阵。建立了基于Stewart结构六维大力传感器的有限元模型,并对传感器有限元模型进行了静力学分析和动力学分析,验证了该力映射矩阵的正确性。提出了六维大力分载比的概念,并综合分析了承载梁结构参数对各方向上分载比的影响,为六维大力传感器的性能指标分析和设计提供了理论基础。针对六维大力传感器的结构特点和设计要求,以力映射矩阵为基础,研究了六维大力传感器各向同性和灵敏度等性能指标,绘制了各性能指标随结构参数变化的功能图谱,为传感器结构参数的选择提供了重要的理论基础。针对巨型重载装备需要多维动态测量的特点,综合分析各转换元件优缺点,选择压电石英作为转换元件。针对六维大力分载后测量杆难于预紧的问题,提出了一种可调预紧力机构和六点局部预紧方法,通过调整预紧螺栓驱动预紧滑块,能够单独对每一根测量杆进行预紧,实现六点局部预紧,并能保证每个测量杆的预紧力值较接近。针对传感器的测量要求和实际安装条件,给出了传感器与被测梁的紧固方案,解决了六维力传感器承载梁上固定和力传递问题。针对六维大力传感器标定的难题,提出并研制了一种单力源六维大力标定装置；研制了30kN量程和200kN量程的六维大力传感器,在六维大力标定装置上对200kN量程六维大力传感器进行了标定,获得传感器的标定矩阵,标定得到传感器的重复性误差在1%以内,线性度在1.2%以内,向间干扰误差在5%以内,X轴力分载比为1.8%,Y轴力分载比为1.6%,Z轴力分载比为0.28%,X轴力矩分载比为17.2%,Y轴力矩分载比为19.1%,Z轴力矩分载比为11.5%,验证了基于Stewart结构并联分载式六维大力传感器的有效性和可行性；根据基于Stewart结构六维大力传感器的结构特点,重点分析了承载梁参数对各向同性和灵敏度性能指标的影响,改变传感器的承载梁直径和长度,并通过其标定矩阵求得各向同性和灵敏度随承载梁参数的变化规律,验证了理论分析曲线的正确性；通过冲击法研究了传感器的动态特性,得到了传感器各通道的固有频率。针对六维大力传感器在线标定的难题,结合重载装备末端执行机构工作时传感器的受力情况和“SFM”标定原理,提出了基于“SFM”标定原理的六维大力传感器在线标定方法,通过应用“SFM”标定方法对有限元模型进行二维、三维、六维的标定,并在六维大力标定装置上对二维力在线标定进行了模拟,验证了该方法应用于多维大力传感器标定的可行性。总之,本论文的基于Stewart结构六维大力传感器的力映射矩阵、传感器的静动力学分析、传感器的性能指标分析、传感器结构设计的关键技术、六维大力标定装置的研制以及传感器的动态特性和在线标定等研究成果为六维大力传感器的设计、开发和应用提供了重要的理论依据和实验基础。更多还原

【Abstract】 Heavy equipments like huge manufacturing equipments, huge operation equipments and huge excavation equipment are characterized by heavy load, large inertia, multi-degree-of freedom, multi-dimensional control of forces and positions. In order to increase productivity and avoid accidents caused by sudden change and of heavy forces, terminus executive arms of heavy equipments should be in compliance with force and displacement. And compliance control and multi-degree harmonious control of terminus executive arms is premised on six-axis heavy force measurement in real time. Therefore, development of six-axis heavy force sensors is of vital importance for real-time measurement of six-axis heavy force. The contradiction of multi-axis and heavy force leads to the difficulty of six-axis heavy force research. In this paper, A six-axis load-sharing heavy force sensor based on Stewart structure is researched, which presents a novel method for multi-axis heavy force measurement.To solve the problem of multi-axis heavy force measurement, a six-axis heavy force measurement method and sensor is proposed. Furthermore, the decoupling algorithm of the six-axis heavy force sensor is deduced from the force mapping matrix of the Stewart structure, the forward kinematics of the Stewart structure and the element stiffness matrix of deep beam. A finite element modal of the six-axis heavy force sensor is established, and analysis of statics and dynamics of the modal is conducted, which verifies the decoupling algorithm. The defination of six-axis heavy force load sharing ratio is presented. The influence of the load bearing beam size on the load sharing ratio is analyzed. All the results above present a theoretical base for performance indice analysis and designment of the six-axis heavy force sensor.To satisfy the designing requirements, the isotropy and sensitivity performance indices of the six-axis heavy force sensor are analyzed according to the force mapping matrix. The performance atlases of the change law of performance indices with the structure parameters are drawn. The entire analysis presents an important theoretical base for the selection of structure parameters.Multi-axis dynamic measurement is necessary for huge operation equipments, so piezoelectric quartz is selected as the sensitive element of the sensor after comprehensive analysis of all sensitive elements. To apply the preload on each measurement rod, a preload structure with adjustable preload and six-site local preload method is presented. Preload of each rod can be applied by ajusting the preload screw bolt and slider, which ensures close preloads on each measurement rod. According to the requirement of measurement and the assembly condition, the wedge expansion technique is used to fasten the sensor on the load bearing beam, which solve the problem of the sensor fasten and force transmission.A six-axis heavy force calibration equipment with single force source is established. Six-axis heavy force sensors with 30kN and 200kN measurement ranges are developed. A six-axis heavy force sensor with measurement range of 200kN is calibrated on the calibration equipment, and the calibration matrix of the sensor is obtained. Results show that the repeatability errors are within 1%, the non-linearity errors are within 1.2% and the interference errors of each direction are within 5%. The load sharing ratio of force is 1.8%,1.6% and 0.28% in X, Y and Z axis respectively. The load sharing ratio of moment is 17.2%,19.1%, and 11.5% in X,Y and Z axis. The calibration results verify the validity and feasibility of the six-axis load-sharing heavy force sensor based on the Stewart structure. The change law of isotropy and sensitivity performance indices with the load bearing beam parameters is obtained by changing the length and radius of the load bearing beam. The change law in experiment is in accordance with the theory curve. The dynamic characteristis of the sensor is researched with force hammer impacting method. The natural frequencies of the sensor in each channel are obtained.Combining the force condition of the manipulator with the calibration principle of "SFM", the on-machine "SFM" calibration method for six-axis heavy force sensor is presented. Calibration of two-axis force, three-axis and six-axis force with "SFM" method is conducted to the finite element modal of the six-axis heavy force sensor, And the sensor is calibrated as two-axis force sensor, which verifies the feasibility of the "SFM" method for the calibration of multi-axis heavy force sensor.In general, the decoupling modal of the six-axis heavy force sensor, the static and dynamic force analysis, the analysis of performance indices, the structure design of the sensor, the calibration equipment, the dynamic character analysis and calibration on machine presented in this paper provide a significant theory and experiment basis for design, development and application of the six-axis heavy force sensor.更多还原