基于驻留指数的振镜伺服系统形状–幅值解耦前馈补偿方法

A Shape-Amplitude Decoupled Feedforward Compensation Method Based on a Dwell Index for Galvanometer Servo Systems

摘要: 针对音圈式振镜伺服系统在低速往复扫描过程中存在的换向误差增大、低速爬行以及迟滞残余较明显等问题，提出一种基于驻留指数的形状–幅值解耦前馈补偿方法。该方法首先采用速度查表插值驱动的加权Play算子网络提取归一化形状因子，用于表征系统迟滞回线的路径记忆与几何形状；其次，基于分段匀速实验构建含经验衰减因子的广义Stribeck模型，用于描述全速度域下的等效幅值变化；进一步，引入基于速度与加速度双阈值判据的驻留指数，用于区分换向邻域与真实低动态状态，并在此基础上构造幅值调制系数，在换向邻域动态压低幅值函数，减小局部过补偿。最终形成“线性粘滞项加法补偿 + 归一化形状因子与自适应幅值乘法调制”的复合前馈控制律。基于Zynq平台搭建实验系统，并在0.5 Hz、8˚正弦往复轨迹下进行对比验证。结果表明，与纯PID控制及传统GPI前馈相比，所提方法在跟踪误差均方根、换向附近局部误差、迟滞残余面积及反馈控制器输出负担等指标上均表现出较好的综合性能。所提方法结构清晰、参数较易辨识，适用于嵌入式振镜伺服实时控制场景。

Abstract: To address the problems of increased reversal error, low-speed creeping, and noticeable hysteresis residuals in voice-coil galvanometer servo systems during low-speed reciprocating scanning, a shape-amplitude decoupled feedforward compensation method based on a dwell index is proposed. First, a velocity lookup-table interpolation driven weighted Play operator network is adopted to extract a normalized shape factor, which characterizes the path memory and geometric features of the hysteresis loop. Second, a generalized Stribeck model with an empirical attenuation factor is constructed from piecewise constant-velocity experiments to describe the equivalent amplitude variation over the full velocity range. Furthermore, a dwell index based on dual thresholds of velocity and acceleration is introduced to distinguish reversal neighborhoods from true low-dynamic states. Based on this index, an amplitude modulation coefficient is further constructed to dynamically reduce the amplitude function near reversal, thereby mitigating local overcompensation. On this basis, a composite feedforward control law is established, consisting of additive compensation of a linear viscous term and multiplicative modulation of the normalized shape factor with the adaptive amplitude function. An experimental platform is implemented on a Zynq system, and comparative tests are conducted under a 0.5 Hz, 8˚ sinusoidal reciprocating trajectory. The results show that, compared with pure PID control and conventional GPI feedforward, the proposed method achieves better overall performance in terms of RMS tracking error, local reversal-region error, hysteresis residual area, and feedback controller output burden. The proposed method features a clear structure and relatively easy parameter identification, making it suitable for real-time embedded control of galvanometer servo systems.