电动舵机伺服机构动力学特性研究
发布时间：2018-10-14 15:04
【摘要】：随着电子设备的日益更新及电气化技术的迅猛发展，伺服电机的工作性能得到了极大的提高，电动舵机伺服机构开始在某些领域取代了传动的气动伺服和液压伺服机构。目前，国内外的众多研究工作关注于对伺服机构控制系统的设计与研究，而对伺服机构本身的动力学特性的研究确极为有限。本文基于建立的电动舵机伺服机构三维模型，首先从刚体动力学的角度分析其运动学特性，以此为基础对考虑弹性条件下伺服机构各组成部分的静刚度和动刚度特性作一定研究，同时还初步探讨了行星滚柱丝杠的运动特性。 首先，对伺服机构中的核心部件行星滚柱丝杠单独进行运动特性分析，建立了行星滚柱丝杠的简化三维模型，分别从轴向和扭转方向研究其相应的刚度特性。对于轴向运动，通过直接刚度法将行星滚柱丝杠处理成一个特殊的弹簧连接系统，通过弹簧刚度等效替代螺纹啮合中所涉及到的多种刚度，由丝杠所受的轴向载荷逐步推导得到弹簧节点位移的分布，以此计算丝杠各部件的轴向变形，并与有限元结果比较，验证推导过程的正确性。对于扭转运动，则考虑了预紧力和丝杠载荷对行星滚柱丝杠扭转刚度的影响规律。 建立电动舵机伺服机构整体的三维模型，忽略伺服机构各部件的弹性，从刚体动力学的角度分析其运动特性，分别得到电机轴、上支耳、摇臂、舵板及下支耳的运动规律，并对舵轴、上支耳与摇臂连接处和下支耳座进行受力分析，给出其支反力及支反力矩的变化规律。 基于多体动力学仿真得到的运动学结果，考虑部件的弹性，对伺服机构的各组成部分的静刚度特性计算，包括电机轴-键-丝杠系统、导向机构和上支耳螺纹连接机构，重点对间隙、预转角等非线性因素对各部分静刚度特性的影响规律进行研究。以此为基础，进一步研究了动态载荷条件下，伺服机构各部分的动刚度特性，给出了其前三阶模态振型和相应的固有频率，同样也归纳得到间隙对动刚度特性的影响规律。结果表明：过盈量对电机轴-键-丝杠系统的刚度特性影响更大，在较小范围内，过盈量能增加其扭转静刚度和扭转动刚度，，超过一定范围之后进一步增加过盈量并不能显著提高刚度数值，而间隙对扭转刚度的影响相对较小，预转角在小范围内对导向机构的扭转刚度影响非常微小。动刚度的变化规律与机构所承受的定载荷有较大关系。
[Abstract]:With the updating of electronic equipment and the rapid development of electrification technology, the performance of servo motor has been greatly improved. The servo mechanism of electric steering gear has begun to replace the pneumatic servo and hydraulic servo mechanism of transmission in some fields. At present, many researches at home and abroad focus on the design and research of servo mechanism control system, but the research on the dynamic characteristics of servo mechanism is very limited. In this paper, based on the 3D model of the servo mechanism of the electric steering gear, the kinematics characteristics of the servo mechanism are analyzed from the point of view of the dynamics of the rigid body. On this basis, the static and dynamic stiffness characteristics of each component of the servo mechanism under elastic conditions are studied. At the same time, the kinematic characteristics of the planetary roller lead screw are preliminarily discussed. Firstly, the motion characteristics of the planetary roller screw, the core component of the servo mechanism, are analyzed separately, and the simplified three-dimensional model of the planetary roller screw is established. The stiffness characteristics of the planetary roller screw are studied from the axial direction and the torsional direction, respectively. For axial motion, the planetary roller lead screw is treated as a special spring connection system by direct stiffness method, and the spring stiffness is equivalent to replace the various stiffness involved in thread meshing. The displacement distribution of spring joint is derived from the axial load of the lead screw step by step. The axial deformation of the parts of the lead screw is calculated and compared with the finite element results to verify the correctness of the derivation process. For torsional motion, the influence of pretightening force and lead screw load on torsional stiffness of planetary roller lead screw is considered. The three-dimensional model of the whole servo mechanism of the electric steering gear is established, and the elasticity of the components of the servo mechanism is ignored. The motion characteristics of the servo mechanism are analyzed from the point of view of rigid body dynamics, and the motion rules of the motor shaft, the upper supporting ear, the rocker arm, the rudder plate and the lower branch ear are obtained, respectively. The force of the rudder shaft, the joint of the upper ear and the rocker arm and the lower branch ear seat are analyzed, and the law of the change of the supporting reaction force and the supporting reverse moment are given. Based on the kinematics results obtained from the multi-body dynamics simulation, the static stiffness characteristics of each component of the servo mechanism are calculated considering the elasticity of the components, including the shaft-key-lead screw system, the guide mechanism and the upper supporting thread connection mechanism. The influence of nonlinear factors, such as clearance and prerotation angle, on the static stiffness characteristics of each part is studied. On this basis, the dynamic stiffness characteristics of each part of the servo mechanism under dynamic load conditions are further studied. The first three modes and corresponding natural frequencies are given, and the influence of clearance on the dynamic stiffness characteristics is also summarized. The results show that the interference amount has a greater effect on the stiffness characteristics of the shaft-key-lead screw system. In a small range, the interference can increase the torsional static stiffness and torsional dynamic stiffness. Further increasing the interference beyond a certain range can not significantly increase the stiffness value, but the influence of clearance on torsional stiffness is relatively small, and the influence of pre-rotation angle on torsional stiffness of guide mechanism is very small in a small range. The variation of dynamic stiffness is related to the constant load of the mechanism.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM383.4
本文编号：2270828
[Abstract]:With the updating of electronic equipment and the rapid development of electrification technology, the performance of servo motor has been greatly improved. The servo mechanism of electric steering gear has begun to replace the pneumatic servo and hydraulic servo mechanism of transmission in some fields. At present, many researches at home and abroad focus on the design and research of servo mechanism control system, but the research on the dynamic characteristics of servo mechanism is very limited. In this paper, based on the 3D model of the servo mechanism of the electric steering gear, the kinematics characteristics of the servo mechanism are analyzed from the point of view of the dynamics of the rigid body. On this basis, the static and dynamic stiffness characteristics of each component of the servo mechanism under elastic conditions are studied. At the same time, the kinematic characteristics of the planetary roller lead screw are preliminarily discussed. Firstly, the motion characteristics of the planetary roller screw, the core component of the servo mechanism, are analyzed separately, and the simplified three-dimensional model of the planetary roller screw is established. The stiffness characteristics of the planetary roller screw are studied from the axial direction and the torsional direction, respectively. For axial motion, the planetary roller lead screw is treated as a special spring connection system by direct stiffness method, and the spring stiffness is equivalent to replace the various stiffness involved in thread meshing. The displacement distribution of spring joint is derived from the axial load of the lead screw step by step. The axial deformation of the parts of the lead screw is calculated and compared with the finite element results to verify the correctness of the derivation process. For torsional motion, the influence of pretightening force and lead screw load on torsional stiffness of planetary roller lead screw is considered. The three-dimensional model of the whole servo mechanism of the electric steering gear is established, and the elasticity of the components of the servo mechanism is ignored. The motion characteristics of the servo mechanism are analyzed from the point of view of rigid body dynamics, and the motion rules of the motor shaft, the upper supporting ear, the rocker arm, the rudder plate and the lower branch ear are obtained, respectively. The force of the rudder shaft, the joint of the upper ear and the rocker arm and the lower branch ear seat are analyzed, and the law of the change of the supporting reaction force and the supporting reverse moment are given. Based on the kinematics results obtained from the multi-body dynamics simulation, the static stiffness characteristics of each component of the servo mechanism are calculated considering the elasticity of the components, including the shaft-key-lead screw system, the guide mechanism and the upper supporting thread connection mechanism. The influence of nonlinear factors, such as clearance and prerotation angle, on the static stiffness characteristics of each part is studied. On this basis, the dynamic stiffness characteristics of each part of the servo mechanism under dynamic load conditions are further studied. The first three modes and corresponding natural frequencies are given, and the influence of clearance on the dynamic stiffness characteristics is also summarized. The results show that the interference amount has a greater effect on the stiffness characteristics of the shaft-key-lead screw system. In a small range, the interference can increase the torsional static stiffness and torsional dynamic stiffness. Further increasing the interference beyond a certain range can not significantly increase the stiffness value, but the influence of clearance on torsional stiffness is relatively small, and the influence of pre-rotation angle on torsional stiffness of guide mechanism is very small in a small range. The variation of dynamic stiffness is related to the constant load of the mechanism.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM383.4
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