It is very difficult to establish mathematical model and use the classics control method or the modern control method in this system.

很难对这类系统建立数学模型及用经典控制方法或现代控制方法实现控制。

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We normally use the punch or hydraulic machine to expand the steel tube, but since the impetus and velocity is difficult to control, the cracking rate of expanding the steel tube reaches to over 10%.

钢管扩管通常采用冲床或液压机来加工，但由于冲力和速度难以控制，扩管破裂率达10%以上。

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We normally use the punch or hydraulic machine to expand the steel tube, but since the impetus and velocity is difficult to control, the cracking rate of expanding the steel tube reaches to over 10%.

钢管扩管通常采用冲床或液压机来加工，但由于冲力和速度难以控制，扩管破裂率达10%以上。

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