【摘要】 高精度时间同步是任务关键型工业网络控制系统的核心支撑技术,针对工业环境中普遍存在周期性振动等扰动信号导致晶振频率漂移,影响时间同步精度的问题,基于扩展比例积分(Proportional integral, PI)观测器,提出一种新型的抗扰补偿器结构,用于消除周期性扰动的影响,并构建了相应的精细抗干扰反馈控制方法,用于实现高精度时间同步.与传统的扰动观测器相比,所提出的扩展PI抗扰补偿器克服了传统扰动观测器零点不变局限性,提出了零点配置方法,以充分利用闭环系统的传递函数矩阵(Transfer function matrix,TFM)在系统零点处降秩的特性,实现了对于特定频率扰动信号的补偿作用.并给出了所提出的控制器和抗扰补偿器的稳定性证明和控制器参数的稳定域.通过基于实测参数的无线网络仿真实验,验证了在5 g周期性振动干扰下,提出的方法明显优于传统滤波器和补偿器,达到了同步误差在4μs以内,实现了高精度时间同步.更多还原

【Abstract】 Precision time synchronization is one of the enabling technologies for mission-critical industrial networked control systems. To address the precision degradation due to crystal oscillator’s frequency drift caused by external disturbances and environment changes, such as the periodic acceleration and vibration which are and commonly found in industrial environments, this paper proposes a novel disturbance compensation structure based on an extended proportional integral(PI) observer for effectively eliminating the effects of periodic disturbances. A disturbance rejection feedback control method is proposed to achieve the precision time synchronization. The proposed extended PI disturbance compensator overcomes the zero-point invariance limitation of the conventional disturbance observer and a zero-point configuration is adopted to make full use of the rank deficiency of the transfer function matrix(TFM) at zeros of the closed-loop system to achieve the compensation effect for frequency-specific disturbance signals. The stability of the proposed controller and disturbance compensator is proved and the convergence domain of the controller parameters is also given. Through the simulation experiments of the wireless network based on measured parameters, it is verified that the proposed method significantly outperforms the conventional observers and compensators and synchronization errors within 4 μs are achieved under 5 g tion.更多还原