【摘要】 电动振动台被广泛应用于振动测试领域，其本质是一个机电耦合换能系统。电动振动台在低频率大位移工况下，其悬挂系统刚度和励磁电流产生的磁场分布均会随动圈位置变化而呈现显著非线性变化。这些非线性因素会导致振动台在低频或超低频振动测试时产生严重的谐波失真，并进一步导致振动台低频振动难以控制。为实现动圈低频运动的精确控制，采用基于模型的前馈控制对驱动电流进行精准补偿。首先，建立了考虑振动台非线性刚度及非线性力系数的集总参数模型，分析并阐述了振动台工作过程中产生非线性现象产生的机理；其次，根据集总参数模型建立了振动台的动力学方程，并结合控制目标和自治方程求解得到系统中状态变量的变化情况，利用非自治方程反推出所需的前馈控制电流；最后，将前馈控制作用下动圈的运动与控制目标进行对比分析。数值算例表明，调整后的驱动电流能够大大缩小低频或超低频工况下振动台动圈的运动状态与跟踪目标之间的差距，有效地抑制了在振动台工作过程中非线性因素带来的谐波失真。该振动台前馈控制方法能够大大提高振动台的工作精度，同时扩大振动台在低频测试时的工作行程和工作频率范围，为振动台控制设计提供了新思路。更多还原

【Abstract】 Electrodynamic shaking table is widely used in vibration testing field, and its essence is an electro-mechanical coupled transduction system. Under low-frequency and large displacement conditions, its suspension system stiffness and magnetic field distribution generated by exciting current exhibit significant nonlinear changes with variation of moving coil position. These nonlinear factors can cause shaking table to have severe harmonic distortion during its testing low-frequency or ultra-low frequency vibrations, and further make it difficult to control low-frequency vibration of shaking table. Here, to realize precise control of low-frequency motion of moving coil, model-based feedforward control was adopted to accurately compensate driving current. Firstly, a lumped parameter model considering nonlinear stiffness and nonlinear force coefficient of shaking table was established to analyze and present the mechanism of nonlinear phenomena occurring in shaking table operating process. Secondly, dynamic equations of shaking table were established according to the lumped parameter model, and changes of system state variables were solved and obtained by combining the control objective and autonomous equations. The required feedforward control current was then derived using non-autonomous equations. Finally, contrastive analysis was performed for moving coil motion and control objective under feedforward control. Numerical examples showed that the adjusted driving current can greatly reduce the gap between motion state of shaking table moving coil and the tracked target under low-frequency or ultra-low frequency conditions, and effectively suppress harmonic distortion caused by nonlinear factors in shaking table operating process; the proposed feedforward control method can greatly improve the working accuracy of shaking table, expand working stroke and working frequency range of shaking table during low-frequency testing, and provide a new idea for shaking table control design.更多还原