新型微耕机磁流变弹性体隔振系统控制策略仿真

目前微耕机设计基本不考虑振动隔离，导致其作业过程中产生的剧烈振动使操作者无法忍受。针对该问题，基于磁流变液的数学模型建立磁流变弹性体变刚度和阻尼的数学模型，计算其等效刚度和等效阻尼，并设计一种新结构磁流变弹性体隔振器，进而建立隔振系统的数学模型，研究刚度和阻尼对系统稳定性的影响。根据磁流变弹性体的性质，建立变刚度和阻尼的控制策略，搭建Simulink仿真模型，采用PID控制、开关控制和未加控制进行仿真分析，通过仿真结果以检验控制效果。结果表明：阶跃输入时，PID控制系统的位移和速度响应能够迅速趋于稳定，开关控制的最大位移幅值是PID控制的2倍，最大速度幅值是PID控制的8倍左右；未加控制的位移和速度响应趋于稳定的时间最长，幅值也最大；多频正弦输入时，未加控制的位移幅值是开关控制的5倍多，是PID控制系统的10倍左右，速度幅值是开关控制的7倍左右，而开关控制的速度幅值略大于PID控制的速度幅值；随机输入时，开关控制的位移幅值整体上小于未加控制，而PID控制的位移幅值整体小于开关控制，且其位移曲线最平滑，速度曲线PID控制波动最小，开关控制次之，未加控制波动最大；混合输入时，未加控制位移和速度幅值分别是开关控制的4倍和7倍左右，开关控制的位移和速度幅值是PID控制的2倍左右，而且PID控制的位移和速度波动最小。综上所述：PID控制策略简单、控制效果最好，为后续工作的控制器开发和实验验证奠定了理论基础。

Control Strategy Simulation Analysis of a New Micro-cultivator MR Elastomer Vibration Isolation System

Vibration isolation is almost not taken into consideration in micro-cultivator design at present. When the machine is running, it will generate excessive vibration and make the operator unbearable. Aiming at solving the problem, the mathematical model of Magnetorheological (MR) Elastomer with variable stiffness and damping was established based on the model of MR fluid and the equivalent stiffness and damping were calculated by the model. Meanwhile, a new structure MR Elastomer vibration isolator was designed and mathematical model of vibration isolation system was built. The influence of stiffness and damping to the system stability was studied then. Subsequently, variable stiffness and damping control strategies were constructed according to the characteristics of MR Elastomer. Based on these data, the Simulink simulation model was constructed to carry out simulation analysis to verify the control effect from the simulation results by adopting PID control, ON/OFF control and no control strategies. The results showed that: In step input, the displacement and velocity responses of PID control system would tend to stability much more rapidly than those of ON/OFF control. The maximum displacement and velocity amplitudes of ON/OFF control were about two times and eight times than those of PID control, respectively; it would take a very long time for displacement and velocity responses of no control tending to stability and the amplitudes were the largest. In multi-frequency sine input, the displacement amplitude of no control was five times more than that of ON/ OFF control and about ten times than that of PID control. The velocity amplitude of no control was seven times than that of ON/OFF control. However, the velocity amplitude of ON/OFF control was slightly larger than that of PID control. In random input, the displacement amplitude of ON/OFF control was smaller than that of no control, but it was larger than that of PID control overall. Furthermore, the displacement curve of PID control was the smoothest. The velocity curve fluctuation of PID control is the smallest, the ON/OFF control is the second, and the fluctuation without control is the largest. In hybrid input, the displacement and velocity amplitudes of no control were about four times and seven times than those of ON/OFF control, respectively and the displacement and velocity amplitudes of ON/OFF control were both two times than those of PID control, respectively. The displacement and velocity curves fluctuation of PID control were the smallest. In conclusion: PID control strategy is simple and PID control effect is the best. It will lay a theoretical foundation for future controller development and experiment verification.