6-UPS并联平台考虑关节摩擦的动力学分析及数值仿真

Dynamic analysis and numerical simulation of 6-UPS parallel mechanism with joint friction

为了对6-UPS并联平台进行动力学分析,基于拉格朗日动力学模型,建立了6-UPS并联平台完整动力学模型。考虑关节摩擦的影响,以"库伦-粘性"摩擦模型为基础,在建立机构关节摩擦模型的基础上,定量分析了机构驱动力受关节摩擦力的影响。为求解因考虑摩擦而建立的非线性动力学模型,本文给出了数值仿真的迭代计算方法。最后以江苏科技大学自制的6-UPS并联船舶运动模拟平台机构为例,求解了液压系统在动平台升沉运动、平移运动、偏航运动、翻滚运动中理想驱动力和含摩擦驱动力随时间的变化关系。结果表明:当机构处于低速运动状态时,关节摩擦力对动力学的影响很小,但驱动力大于原理想动力学情况下的0.005%;当机构处于高速运动状态时,关节摩擦力对动力学的影响会显著增加,但驱动力不会超过原理想动力学情况下的0.25%。本文结果为下一步控制系统的设计提供了理论依据。

The kinematics of a 6-UPS parallel mechanism is analyzed. A full dynamic model of a 6-UPS parallel platform is built based on Lagrangian dynamics model. In order to solve the nonlinear dynamic model with friction being considered, this paper presents a numerical simulation method of iterative calculation. At last, we adopt the mechanism of 6-UPS parallel ship simulation platform as an example. Under different working conditions of moving stages such as heaving movement, translational movement, yaw movement and roll movement of hydraulic system, the relationships between the ideal driving force and time, the friction driving force and time, are solved, which provides theoretical basis for the design of the control system in the next step.