The;
State;
Key;
Lab;
of;
Fluid;
Power;
Transmission;
and;
Control;
Zhejiang;
University,;
Hangzhou;
310027,;
China;
College;
of;
Mechanical;
Engineering;
and;
Automation,;
Zhejiang;
Sci-Tech;
University,;
Hangzhou;
310018,;
China;