摘要
针对空气弹簧水平多点支撑自由边界模拟系统存在的过约束、难收敛和非线性控制问题,首先,采用自由度解耦控制方式,在削弱系统内力的基础上,将空间自由度的控制目标分解为每一个控制通道的控制目标,解决了系统过约束问题;其次,利用改进积分分离(proportion integration differentiation,简称PID)控制算法克服系统超调,解决了系统震荡收敛问题;最后,采用经验数据对空气弹簧刚度进行实时二维插值补偿,解决了系统非线性问题.实测结果表明,该控制系统设计合理,系统运行过程平稳,通道间同步性较好,控制策略满足模态试验边界的模拟要求.
Abstract
The control problems existing in the free boundary simulation system which is formed by horizontal multi-point support air springs are severe over-constraints,convergence difficulty and the object non-linear.The decoupling control strategy of 3-degree of freedom motions is applied for over-constraints.The control target is transformed from degrees of freedom to control channels.Meantime,the internal forces are weakened.The im-proved integral discrete proportion integration differentiation(PID)algorithm is used for overcoming system overshoot.Based on the experiential data,the nonlinear stiffness of air spring is compensated by two-dimensional linear interpolation in real time.The field testing shows that the control process is smooth,the algo-rithm can guarantee synchronization well.In conclusion,the control algorithm meets the requirement of simulate-free boundary for modal test.
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