| 摘要 |
A tandem electrohydrostatic actuator (70) broadly includes a first piston (22) operatively arranged in a first cylinder (23), and a second piston (24) operatively arranged in a second cylinder (25). The pistons are coupled to move together. The first piston has a small extend area (35) and a large retract area (36). The second piston has a large extend area (38) and a small retract area (39). The large areas (36, 38) of the pistons are equal to one another and the small areas (35, 39) of the pistons are equal to one another. A reversible fixed-displacement first pump (45) has equal inlet and outlet flows supplied to the small areas of the first and second pistons, respectively. A reversible fixed-displacement second pump (40) has equal inlet and outlet flows supplied to the large areas of the first and second pistons, respectively. The total volume of the fluid in the actuator remains constant at all positions of the pistons. In the preferred embodiment, a connecting rod (26) joins the pistons, an output rod (29) is connected to the first piston and penetrates an end wall (30) of the first cylinder, and a stationary LVDT coil or body (31) has one end attached to an end wall (32) of the second cylinder and has its movable core connected to the connecting rod.
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