The H∞ loop shaping method was proposed for the design of a pitch control system .A T-foil was used as a moving actuator to control the pitch of a high speed ferry .It is installed on the bottom of the vessel near the bow .The wave height disturbance is the output disturbance of the system .So the sen-sitivity of the system was chosen as the design specification .Sensitivity analysis shows that the perform-ance of the PD control for such systems is poor .So a novel design based on the compensation of the com-plex poles of the vessel was proposed .The H∞loop shaping method was used to guarantee the robustness and stability of the system .The design is verified by simulation .The constraints of the angle and the rate of the actuator were also considered during simulation .The mathematical model of the vertical motion of the ship and the wave model were used to calculate the sea-sickness index MSI under the new compensa-tion design .The result shows that the performance of the design based on the concepts of sensitivity and pole compensation is better than that of the PD and QFT design .%提出了H∞回路成形方法来设计纵摇控制系统.快速渡轮的纵摇角由位于船艏下方的T型水翼来控制.海浪的扰动是系统输出端的扰动,所以取灵敏度作为设计指标.对灵敏度的分析表明,这类纵摇系统采用PD控制时的性能是较差的.为此提出了对复数极点进行补偿的设计方案,并采用H∞回路成形设计来保证系统的稳定性和鲁棒性.设计结果用仿真进行了验证.仿真时考虑了执行机构的速率限制和行程限制.基于整船模型和海浪模型仿真计算了采用极点补偿后船舶的晕船率(motion sickness incidence,MSI)指标.设计和仿真表明,这种基于灵敏度和复数极点补偿的设计,其性能优于PD控制和完全基于定量计算的QFT(quantitative feedback theory)设计.
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