基于零点状态跟踪法的小间隙轴孔装配策略

Assembly Strategy of Small Clearance Shaft Hole Based on Zero-Point State Tracking Method

摘要:

在小间隙轴孔精密装配过程中，需要分析传感器检测的力与力矩信息，判断轴孔相对的位置与姿态，从而判断接触状态决定调整方向。由于接触力和力矩与轴的位姿高度耦合，因此装配过程中五个方向上的力与力矩存在耦合作用，各个力之间会相互影响，导致调控收敛慢。为减少耦合造成的震荡，提高调控效率，提出一种基于零点状态跟踪法的柔顺装配策略。该策略依据轴孔交互力信息实现轴与孔的对齐，在装配阶段对轴孔交互模型进行分析，绘制接触状态-受力关系图，对调整过程中接触状态进行识别，在该调整策略下，在姿态角调整前预先进行位置调整，使得径向接触力为0 N,跟踪两点接触状态中的水平力“零点”，消除第一类力矩的影响，让角度调整量只受角度偏差的影响，在控制层面上将轴孔自动化装配的复杂多维力控制问题解耦。实验结果表明，采用所设计的装配策略，调控时间减少了40%。即采用该策略能提高调控效率，快速实现轴孔装配力和力矩调整。

Abstract:

In the precisive process of small clearance shaft holes assembly, the relative position and attitude of the shaft and holes are determined based on the force and torque information detected by the sensors, and then the contact status is clarified to determine the adjustment direction. Due to the high coupling of contact force and torque with the pose of the axis, there is a coupling effect between forces and torque in five directions during the assembly process. Each force will affect each other, leading to the slow convergence of control. To reduce the oscillation caused by coupling and improve control efficiency, a compliant assembly strategy based on zero-point state tracking method is proposed. This strategy aligns the shaft and hole based on the interaction force information between the shaft and hole. During the assembly stage, the interaction model between the shaft and hole is analyzed and a contact state force relationship diagram is drawn to identify the contact state during the adjustment process. Under this adjustment strategy, the position is adjusted in advance before adjusting the attitude angle, so that the radial contact force is 0 N. The horizontal force "zero point" in the two-point contact state is tracked to eliminate the influence of the first type of torque, decoupling the complex multi-dimensional force control problem of automated assembly of shaft holes at the control level by ensuring that the angle adjustment is only affected by angle deviation. The experimental results show that using the designed assembly strategy, the control time is reduced by 40%. So，using the zero-point state tracking method can improve regulation efficiency and quickly achieve adjustment of assembly force and torque between shaft and hole .