【摘要】 针对设施蔬菜表型信息采集过程中，由于地形不平整产生3～6 Hz振动造成采集装置出现高频小角度倾斜、动态响应滞后，进而导致采集图像分辨率下降等问题，设计了基于重力补偿角加速度双前馈-改进串级PID复合控制系统的适用设施表型采集装置的稳衡云台。硬件上，针对30 cm窄行距与多源传感器搭载需求，设计300 mm×280 mm×250 mm单臂稳衡云台，整机仅5 kg,最大负载能力达15 kg。集成X-Y-Z轴重心滑轨，将负载重心偏差控制在±5 mm,由此引起的重力矩波动小于0.5 N·m。控制策略上，通过线性拟合构建重力补偿前馈模型(R~2=0.991 2),以抵消重力矩干扰。提出内环速度环叠加外环位置环的改进串级PID,引入积分分离、积分限幅及误差过零复位机制，解决传统PID小角度调整积分饱和问题，稳态误差控制在0.1°以内。融合载体与云台双IMU角加速度前馈，抵消采集车2～3 m/s~2启停/转向带来的惯性扰动。运行效果验证试验表明，复合控制使系统阶跃响应时间缩短80%且全程无超调。采集车以0.5 m/s行驶时，云台三轴角度围绕目标值小幅度振荡，其中横滚轴角度±0.5°、俯仰轴角度±0.3°、航向轴角度±0.2°,满足设施蔬菜表型采集对姿态稳定性的要求。更多还原

【Abstract】 In greenhouse vegetable phenotyping, uneven terrain induces high-frequency vibrations in the 3～6 Hz range, leading to small-angle vibration and hysteresis in the acquisition device, which degraded the resolution of collected images. A stabilized platform was developed based on a composite control system incorporating gravity-compensated dual angular acceleration feedforward and an improved cascade PID controller. A single-arm stabilized platform with dimensions of 300 mm×280 mm×250 mm was constructed to accommodate a narrow line spacing of 30 cm and support the integration of multi-source sensors. The stabilized platform had a self-weight of 5 kg and can carry a payload of 15 kg. It was equipped with X-Y-Z axis sliding rails for center-of-gravity adjustment, limiting the center-of-gravity deviation to within ±5 mm and maintaining gravitational torque variation below 0.5 N·m. A gravity compensation feedforward model was established by linear fitting, achieving a determination coefficient R~2 of 0.991 2. An improved cascade PID structure was implemented, combining an inner velocity loop with an outer position loop. Key enhancements included integral separation activated when the error exceeded 1°, integral limiting, and a resetting mechanism triggered by error zero-crossing. These measures effectively suppressed integral saturation during fine adjustments, achieved a steady-state error of 0.1°. In addition, angular acceleration feedforward from dual IMUs mounted on both the vehicle and the stabilized platform compensated for inertial disturbances caused by vehicle start-stop and turning accelerations of 2～3 m/s~2. The verification test results showed that the composite control strategy reduced the system step response time by 80% without overshoot. When the vehicle operated at 0.5 m/s, the stabilized platform’s triaxial angular oscillation was constrained to ±0.5° in roll, ±0.3° in pitch, and ±0.2° in yaw. These outcomes confirmed that the system satisfied the requirements for high-accuracy phenotyping acquisition.更多还原