求翻译：根据设计要求选取齿轮的质量作为目标函数，即对齿轮的质量进行优化，假定齿轮材料密度均匀，则目标函数可等价转化为齿轮体积的最小化。是什么意思？

Selected according to design requirements of the quality of gear as the objective function, namely to optimize the quality of the gear, the gear material density is assumed uniform, then the objective function can be transformed into the equivalent volume of minimal gear.

According to the design requirements for gear selection of quality as a goal, namely, to gear the quality function optimized gear materials, it is assumed that the target density evenly, function may be equivalent into gear the size of the smallest.

Requests according to the design to select the gear the quality to take the objective function, namely the counter gear quality carries on the optimization, supposes the gear material density to be even, then the objective function may transform equally as the gear volume minimum.

Select gear quality based on the design requirements as the objective function, namely, to optimize the quality of gears, assuming that the gear materials density, the objective function may into gear the equivalence volume is minimized.

Selected according to design requirements of the quality of gear as the objective function, namely to optimize the quality of the gear, the gear material density is assumed uniform, then the objective function can be transformed into the equivalent volume of minimal gear.