摘要
The analytical formulations of the velocity and the acceleration of a 2-DOF spherical parallel mechanism are derived by the screw theory. Based on building its dynamics model by the principle of virtual work and reciprocal product of the screw, the equation of the motor moment is obtained. Through the transformation of dynamics model, the configuration space method of the dynamics equation and the corresponding coefficients are presented. Finally, the result of an example shows that the inertia moment and the gravity play a more important role than the coriolis and centrifugal moment, and the former is ten times of the latter in the magnitude. So, the latter can be neglected only when the velocity of mechanism is very slow.
运用旋量理论的方法推导出两自由度球面并联机构的速度、加速度解析表达式,在此基础上依据虚功原理和旋量的互易积形式建立了该机构的动力学模型,得到了两驱动电机的驱动转矩方程。通过对动力学模型的变换,获得了动力学方程的形位空间模式及相关系数。通过一个实例表明,动力学方程中的惯性系数和重力项占有的比重较大,而哥氏力系数和离心力系数占有的比重较小,他们在数值上相差一个数量级。但是否可以忽略后者需要判断速度的大小,只有当机构运动速度较小时才可以将哥氏力和离心力忽略。
基金
Supported by the National Natural Science Foundation of China (50375071)
the Jiangsu Province Key Lab on Digital Manufacture Project (HGDML-0604)~~
