冗余驱动液驱振动台台阵系统内力分析及其抑制方法研究

冗余驱动振动台台阵系统误差不仅会造成单个振动台内力,也会使振动台之间产生台阵内力,这会减小系统的净出力,甚至损坏试件。首先应用冗余驱动并联机构动力学原理,分析冗余驱动振动台台阵系统内力的形成机理;建立台阵系统的内力耦合模型,推导系统的机械安装误差、位移测量误差和伺服阀零偏三种主要误差因素与振动台内力和台阵内力的数学关系式,进而定量地分析上述误差对系统内力的影响机理。然后结合动力学关系得到振动台的内力合成矩阵和自由度广义力合成矩阵,并根据系统内力的形成机理和影响机理,分别设计了比例-积分控制器对振动台内力和台阵内力进行抑制。最后,利用Sim Mechanics软件建立冗余振动台台阵系统动力学模型,结合Simulink软件建立其控制系统模型并进行联合仿真验证。仿真结果表明:该方法对台阵系统内力影响机理分析正确和提出的内力抑制方法能够有效地消除系统内力。

Inner coupling force analysis and suppression for redundant-drive hydraulic shaking tables

The table array system errors of redundantly-driven electro-hydraulic shaking tables not only lead to inner coupling force in each shaking table, but also lead to inner coupling forces between shaking tables. The inner coupling forces can reduce the net output force of the system and even may damage specimens. Here, the redundantly driven parallel mechanism dynamics was used to analyze the formation mechanism of the inner coupling force and establish the model of the inner coupling force. The mathematical relationship equations for inner coupling forces in a shaking table and those between shaking tables versus installation errors, displacement measurement errors and servo valve zero-bias of the system were derived. The influence mechanism of the errors mentioned above on the inner coupling forces was analyzed quantitatively. The inner coupling force synthesis matrix and the generalized forces of all DOFs. synthesis matrix were derived applying the dynamics relations and then the inner coupling force suppression controllers based on proportional-integral controllers were respectively designed according to the influence mechanism and the formation mechanism of the inner coupling forces. The dynamic model of a shaking table array system was built using the software SimMechanics and its control model was built using Simulink. The co-simulations were performed and the simulation results indicated that the analysis of the shaking table array systems inner coupling forces is right and the proposed control strategies can reduce the inner coupling forces effectively.