Patent ID: 11867207
Assignee: TSINGHUA UNIVERSITY
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F  G | IPC F  G

Claim 0:
1. An electro-hydraulic servo actuator capable of implementing long-stroke and high-frequency loading, comprising:
a long hydraulic cylinder with a piston;
a short hydraulic cylinder with a piston;
a fixed-end rod having one end connected to the piston of the long hydraulic cylinder, and the other end fixed;
a low frequency electro-hydraulic servo valve and a high frequency electro-hydraulic servo valve, the low frequency electro-hydraulic servo valve and the high frequency electro-hydraulic servo valve being configured to convert electrical signals into hydraulic pressure flow control signals to control hydraulic pressure changes in left and right chambers of the hydraulic cylinders to implement corresponding piston movements;
a left rod chamber and a right rod chamber; and
a force applying end head and a force applying end rod, wherein the force applying end rod is connected to the piston of the short hydraulic cylinder and the force applying end head to output a movement of the piston of the short hydraulic cylinder to the force applying end head, the force applying end head has one end connected to the force applying end rod through a hinge joint, and the other end connected to a specimen under a load test, thereby applying a target large-displacement and high-frequency excitation to the specimen under the load test,
wherein a piston displacement of the short hydraulic cylinder comprises a small-displacement and high-frequency movement of the piston of the short hydraulic cylinder relative to the short hydraulic cylinder under hydraulic pressure changes controlled by the high frequency electro-hydraulic servo valve, and a large-displacement and low-frequency movement generated by the short hydraulic cylinder itself along with the long hydraulic cylinder,
wherein the piston displacement of the short hydraulic cylinder is a large-displacement and high-frequency movement generated by a combination of the small-displacement and high-frequency movement and the large-displacement and low-frequency movement.