The model of voice coil motor and optical pickup unit are analyzed, the model parameters are tested, the model of DVD focus servo system is built and the simulation is carried out.

分析了DVD聚焦伺服系统中音圈电机和光头拾取器的数学模型，通过实验测定其模型参数，完成了DVD聚焦伺服系统的建模，并进行了仿真。

youdao

That explosion shattered glass on several storefronts and left the stricken police unit's modified Ford pickup truck charred and mangled.

NPR: Alarm Grows As Iraqi Forces Fail To Stem Violence

Analysts point out that the company is not particularly competitive in the pickup and SUV markets, which are still important high margin vehicles even with unit volumes well below the peaks of a few years ago.

FORBES: Can Detroit Accelerate?