假如你是一个经验丰富的翻译家，请把下面这段文字流畅的学术性的翻译成英文：如图3（a）所示，系统在初始阶段稳定运行，然后太阳辐射开始以不同的幅度脉动，以测试控制策略对干扰的控制效果。以平方误差积分和（ISE）作为性能指标，比较不同控制方案的性能。太阳辐射脉冲干扰下不同控制方案的ISE值如表1所示。图3（b）（c）显示了不同控制策略下氢气分数和甲烷转化率的变化。可以看出，无论加入哪种控制策略，受控变量的偏差都明显小于非受控变量。这意味着使用控制策略可以显著提高所生产氢气的质量。从图3（b）（c）可以看出，在基于ANN的PI混合控制下，氢气分数与设定值之间的偏差最小，甲烷转化率的偏差也小于在PI反馈控制和ANN前馈控制下的偏差，并且表1中基于ANN的PI混合控制的ISE值也比PI反馈控制和ANN前馈控制的ISE值小一个数量级。这意味着基于神经网络的PI混合控制的性能明显优于其他控制策略。在太阳辐射脉冲的干扰下，基于神经网络的PI混合控制可以保持产出氢气分数的稳定，并将甲烷转化率保持在0.95，从而使甲烷得到充分利用。

As shown in Figure 3(a), the system operates stably in the initial stage, and then the solar radiation begins to fluctuate with different amplitudes to test the control effect of the control strategy on disturbances. Using the integral of squared error (ISE) as the performance indicator, the performance of different control schemes is compared. The ISE values of different control schemes under solar radiation pulse interference are shown in Table 1. Figures 3(b) and 3(c) show the variations of hydrogen fraction and methane conversion rate under different control strategies. It can be seen that regardless of which control strategy is adopted, the deviation of the controlled variable is significantly smaller than that of the uncontrolled variable. This means that the use of control strategies can significantly improve the quality of the produced hydrogen. From Figures 3(b) and 3(c), it can be seen that under the ANN-based PI hybrid control, the deviation between the hydrogen fraction and the set value is the smallest, and the deviation of the methane conversion rate is also smaller than that under PI feedback control and ANN feedforward control. Moreover, the ISE value of the ANN-based PI hybrid control in Table 1 is an order of magnitude smaller than that of PI feedback control and ANN feedforward control. This means that the performance of the neural network-based PI hybrid control is significantly better than other control strategies. Under the interference of solar radiation pulses, the ANN-based PI hybrid control can maintain the stability of hydrogen production and keep the methane conversion rate at 0.95, thereby making full use of methane.