高地隙喷雾机主动空气悬架减振控制与实验

Experiments of Vibration Control for Active Pneumatic Suspension System in High Clearance Self-propelled Sprayer

高地隙自走式喷雾机在接近于系统固有频率的地面条件下工作时,由于车身重心高、喷杆质量大且展开后较长,导致工作时车身与喷杆大幅剧烈摆动,影响作业质量甚至危及安全。针对此,本文提出适时开启的主动空气悬架减振方案。方案实施过程中,一方面需要解决空气弹簧充放气过程中的非线性控制问题,另一方面则需面对车身加速度与位移多变量同时控制以及最大控制力和悬架行程受限的传统问题。为此,制定了一种空气悬架H∞状态反馈与时频非线性联合减振控制策略。首先求解系统在约束条件下的H∞状态反馈控制器增益,基于此控制器可计算系统在地面扰动下的空气弹簧所应实施的目标压力;然后设计时频非线性控制器,依靠该控制器实时调节比例电磁阀开度进而控制空气弹簧压力使其跟随目标。基于室内台架实验,在模拟地面条件接近于系统固有频率以及田间随机路面激励两种工况下,对所提策略进行了验证。结果表明,系统在一阶共振频率的激励下,被动悬架簧载质量最大加速度达8.5 m/s2左右,半主动悬架的最大加速度约为7 m/s2,而主动空气悬架的最大加速度降低至2.5 m/s2,并在主动控制过程中,悬架位移始终保持在限制范围内,激振结束后悬架位移逐渐恢复至零初始位置;在随机田间路面激励工况下,主动控制悬架的车身加速度亦显著降低,证明了主动减振方案的有效性。

Owing to high center of mass, long and heavy spray beam, the high clearance self-propelled sprayer has a tendency to swing when it runs on the bumpy farmland. Especially the frequency of the excitation from ground is approximately the inherent frequency of the suspension, which will result in reduction of work quality or even endangering security of itself. So a scheme of an active pneumatic suspension controlled in due course was put forward to address the issue. But in practical control process of the active pneumatic suspension, several problems need to be taken into account simultaneously, including the nonlinearities existed in the air spring system, requirements about muhivariable control of the acceleration and displacement as well as the constrained conditions for output force or suspension frequecy of the system, the maximum sprung mass acceleration of passive pneumatic suspension was about 8.5 m/s^2 , that of the semi-active suspens on was approximately 7 in/s^2 , whereas thai of the active suspension was decreased to 2.5 m/s^2. In whole control process, the displacement of suspension was controlled within the limitation and reverted In initial position after impacting. Besides, responses under the condition of road random excitation were also tested. All results showed the validation of the active vibration suppressed scheme as well as the vibration control method mentioned.