The dual-drive feed mechanism (DDFM) based on the drive at the center of gravity (DCG) principle has been widely adopted in computer numerical control (CNC) machines and industrial robots that require high precision and high stability. The friction force affected by feed rates and moving parts positions can change the contact stiffness of kinematic joints, which can further impact on dynamic characteristics of the DDFM and cause dual axes difference. Considering the contact stiffness of kinematic joints, this paper adopts the lumped parameter method to establish the general dynamic model of the DDFM. The equivalent axial stiffness of kinematic joint and feed system transmission stiffness are all derived regarding the influence of feed rates and moving parts positions. The dynamic experiments on the DDFM with different feed rates and moving parts positions are carried out to verify the proposed model. The results suggest that in the motion stage, the DDFM’s natural frequency is greater than that in the static stage, and behaves differently in different feed rates and moving parts positions. The axial contact stiffness value of the ball-screw and nut B can reach 0 when the feed rate increases. When the moving parts are in the middle position of the crossbeam, the DDFM is the most stable and the dynamic performance is the best.

基于重心驱动（DCG）原理的双驱动进给机构（DDFM）已广泛用于要求高精度和高稳定性的计算机数控（CNC）机器和工业机器人中。受进给速度和运动部件位置影响的摩擦力会改变运动关节的接触刚度，从而可能进一步影响DDFM的动态特性并引起双轴差。考虑到运动关节的接触刚度，本文采用集总参数法建立了DDFM的通用动力学模型。运动学关节的等效轴向刚度和进给系统的传动刚度都是根据进给速度和运动部件位置的影响得出的。在具有不同进给速度和运动部件位置的DDFM上进行了动态实验，以验证所提出的模型。结果表明，在运动阶段，DDFM的固有频率要大于静止阶段的固有频率，并且在不同的进给速度和运动的零件位置下，其行为会有所不同。当进给速度增加时，滚珠丝杠和螺母B的轴向接触刚度值可以达到0。当活动部件位于横梁的中间位置时，DDFM最稳定，动态性能也最好。当进给速度增加时，滚珠丝杠和螺母B的轴向接触刚度值可以达到0。当活动部件位于横梁的中间位置时，DDFM最稳定，动态性能也最好。当进给速度增加时，滚珠丝杠和螺母B的轴向接触刚度值可以达到0。当活动部件位于横梁的中间位置时，DDFM最稳定，动态性能也最好。