Electro-hydraulic actuation system and control method

Abstract

The application provides an electro-hydraulic actuating system and a control method. The system comprises at least one hydraulic power module and a hydraulic actuating unit. The hydraulic power module provides power for the movement of the hydraulic actuating unit. The hydraulic power module comprises a hydraulic driving unit and a flow distribution unit. The hydraulic driving unit reciprocates according to the received control signal, so that the two oil ports O1 and O2 of the hydraulic driving unit alternately generate pressure oil. The pressure oil is controlled by the opening and closing logic of the flow distribution unit, and is delivered to the two oil ports X and Y of the hydraulic actuating unit, so as to cause the movement of the hydraulic actuating unit. The moving parts in the system are linear reciprocating movements, all the forces are axial, there is no complex intermediate transmission link, no movement conversion link, no introduction of lateral force, the friction to be overcome in the movement is smaller, the mechanical efficiency is higher, and the working life cycle is longer.

Description

Technical Field

[0001] This invention relates to an electro-hydraulic actuation system and control method, belonging to the field of hydraulic servo control technology. Background Technology

[0002] Electro-hydraulic actuators are closed-loop hydraulic servo solutions based on the principle of volumetric control. By avoiding the use of numerous long hydraulic lines and servo valves, they significantly improve system reliability, maintainability, and power density. Therefore, electro-hydraulic actuators are widely used in servo control systems for medium and large-sized aircraft, legged robots, and other applications.

[0003] Existing electro-hydraulic actuators, which use a servo motor-bidirectional axial piston pump as a power source, suffer from several drawbacks under high-pressure and high-speed conditions. These drawbacks include enhanced multi-field coupling effects within the piston pump, increased nonlinear overturning moments in structural components, intensified fluid instability, a sharp rise in the likelihood of friction pair failure, and difficulty in maintaining stable oil film bearing capacity. Furthermore, the motor-hydraulic pump rotor system exhibits high rotational inertia, resulting in slow system response and narrow bandwidth. All these issues contribute to the deficiencies in reliability and dynamic characteristics of existing electro-hydraulic actuators. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electro-hydraulic actuation system and control method.

[0005] The technical solution of the present invention: an electro-hydraulic actuation system, comprising at least one hydraulic power module and a hydraulic actuator, wherein the hydraulic power module provides the power for the movement of the hydraulic actuator;

[0006] The hydraulic power module includes a hydraulic drive unit and a distribution unit. The hydraulic drive unit reciprocates according to the received control signal, causing its two oil ports O1 and O2 to alternately generate pressurized oil. The pressurized oil is then delivered to the two oil ports X and Y of the hydraulic actuator through the opening and closing logic control of the distribution unit, causing the hydraulic actuator to move.

[0007] A control method for an electro-hydraulic actuation system includes the following steps:

[0008] When the hydraulic actuator needs to move in the direction of the piston chamber at port Y, the hydraulic drive unit, according to the control signal, first moves in the opposite direction of the required movement. Oil flows out through port O1 of the hydraulic drive unit. At this time, high-speed switching valves A and D open, while B and C close. Pressurized oil enters through port X of the hydraulic actuator unit, pushing the piston of the actuator unit in the required movement direction. Oil flows out through port Y of the hydraulic actuator unit and enters the hydraulic drive unit through port O2. Then, according to the control signal, the hydraulic drive unit moves in the required movement direction again. Oil flows out through port O2. At this time, high-speed switching valves A and D close, while B and C open. Pressurized oil enters the hydraulic actuator unit through port X, pushing the piston of the actuator unit in the required movement direction. Oil flows out through port Y of the hydraulic actuator unit and enters the hydraulic drive unit through port O1.

[0009] When the hydraulic actuator needs to move in the direction of the piston chamber located at port X, the hydraulic drive unit moves in the desired direction according to the control signal. The oil flows out through port O1. At this time, the high-speed switching valves A and D are closed and B and C are open. The pressurized oil enters through port Y of the hydraulic actuator, pushing the piston of the actuator to move in the desired direction. The oil flows out through port X and enters the hydraulic drive unit through port O2. The hydraulic drive unit moves in the opposite direction according to the control signal. The oil flows out through port O2. At this time, the high-speed switching valves A and D are open and B and C are closed. The pressurized oil enters the hydraulic actuator through port Y, pushing the piston of the actuator to move in the desired direction. The oil flows out through port X and enters the hydraulic drive unit through port O1.

[0010] The beneficial effects of this invention compared to the prior art are as follows:

[0011] (1) All moving parts in the system of the present invention are linear reciprocating motions, all forces are along the axial direction, there are no complex intermediate transmission links, no motion conversion links, and no introduction of lateral forces. The friction force that needs to be overcome in its motion is smaller, the mechanical efficiency is higher, and the working life cycle is longer.

[0012] (2) The present invention has a small moment of inertia of the mover, and the frequency response characteristics of the system are theoretically only related to the frequency response of the linear motor and the high-speed switching valve, which has a significant advantage of fast response;

[0013] (3) The hydraulic power of the present invention can be connected in parallel to realize the doubling of system power. In actual use, different numbers of hydraulic power can be called according to the load conditions, avoiding the waste of system input power when the power output is low, realizing adaptive load matching, and multiple hydraulic power can be used as backups for each other, which facilitates the formation of redundancy configuration and fault isolation, and improves the reliability of actuator.

[0014] (4) All control in this invention can be achieved through digital signals, without the need for digital-to-analog conversion hardware, which greatly simplifies the hardware composition and control logic of the host computer control system. Attached Figure Description

[0015] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0016] Figure 1 This is a schematic diagram of a linear drive electro-hydraulic actuator for high-speed switching valve flow distribution according to a specific embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the reciprocating hydraulic drive unit structure in a linear drive electro-hydraulic actuator for high-speed switching valve distribution according to a specific embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of the hydraulic power module in a linear drive electro-hydraulic actuator for high-speed switching valve distribution according to a specific embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the four-quadrant working mode of a linear drive electro-hydraulic actuator for high-speed switching valve distribution according to a specific embodiment of the present invention.

[0020] Figure 5 This is a high-speed switching valve control logic matrix of a linear drive electro-hydraulic actuator for high-speed switching valve distribution according to a specific embodiment of the present invention;

[0021] Figure 6 This is a schematic diagram of the follow-up working mode of a linear drive electro-hydraulic actuator for high-speed switching valve flow distribution according to a specific embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of a multi-hydraulic power module parallel mode of a linear drive electro-hydraulic actuator for high-speed switching valve flow distribution according to a specific embodiment of the present invention. Detailed Implementation

[0023] This invention provides an electro-hydraulic actuation system that uses a linear motor as a power source and a high-speed switching valve assembly for flow distribution to achieve precise control of the actuator cylinder's movement. The linear motor drives a double-acting piston cylinder to form a reciprocating piston pump unit, and the high-speed switching valve assembly forms a flow distribution unit.

[0024] An electro-hydraulic actuation system includes at least one hydraulic power module and a hydraulic actuator, wherein the hydraulic power module provides the power for the movement of the hydraulic actuator.

[0025] The hydraulic power module includes a hydraulic drive unit and a distribution unit. The hydraulic drive unit reciprocates according to the received control signal, causing its two oil ports O1 and O2 to alternately generate pressurized oil. The pressurized oil is then delivered to the two oil ports X and Y of the hydraulic actuator through the opening and closing logic control of the distribution unit, causing the hydraulic actuator to move.

[0026] Furthermore, the hydraulic drive unit includes a linear motor and a piston pump. The mover of the linear motor is fixedly connected to the piston of the piston pump. The linear motor receives a current signal from the controller and drives the piston of the piston pump to reciprocate, thereby generating pressurized oil at the two oil ports O1 and O2 of the piston pump. Preferably, the piston of the piston pump has the same area on both sides.

[0027] Furthermore, the piston pump cylinder body consists of two independent chambers, with oil ports O1 and O2 located on different chambers respectively.

[0028] Furthermore, the linear motor's mover is fixedly connected to the piston of the piston pump via a coupling, and the linear motor's mover, coupling, and piston together constitute the hydraulic drive unit's mover.

[0029] Furthermore, the flow distribution unit includes at least four high-speed switching valves, wherein one side of switching valves A and B is connected to the hydraulic drive unit port O1, one side of switching valves C and D is connected to the hydraulic drive unit port O2, the other side of switching valves A and C is connected to the hydraulic actuator unit port X, and the other side of switching valves B and D is connected to the hydraulic actuator unit port Y.

[0030] Furthermore, the hydraulic actuator includes an actuator cylinder and an actuator piston. The actuator cylinder includes two independent piston chambers, with oil port X and oil port Y respectively located in different chambers. Preferably, the hydraulic actuator piston has the same area on both sides.

[0031] Furthermore, the opening and closing logic control of the high-speed switching valve of the distribution unit is as follows:

[0032] When the hydraulic actuator needs to move towards the piston chamber where the oil port Y is located, the hydraulic drive unit first moves in the opposite direction of the required movement direction. At this time, the high-speed switching valves A and D open and B and C close. Then the hydraulic drive unit moves in the required movement direction, at which time the high-speed switching valves A and D close and B and C open.

[0033] When the hydraulic actuator needs to move towards the piston chamber where port X is located, the hydraulic drive unit first moves in the desired direction. At this time, high-speed switching valves A and D are closed and B and C are open. Then the hydraulic drive unit moves in the opposite direction of the desired direction. At this time, high-speed switching valves A and D are open and B and C are closed.

[0034] Furthermore, the frequency of the hydraulic drive unit's movement is consistent with the opening and closing control frequency of the high-speed switching valve group. The reciprocating motion of the hydraulic drive unit will continuously inject pressurized oil into the hydraulic actuator's oil port X or Y through the distribution unit, driving the hydraulic actuator's piston rod to produce continuous movement in a certain direction.

[0035] Furthermore, the flow distribution unit also includes a switching valve E, which is connected to the hydraulic actuator port X and port Y on both sides.

[0036] Furthermore, when the hydraulic actuator does not need to output motion and is in a follow-up state, the hydraulic drive unit does not generate motion. At this time, high-speed switching valves A, B, C, and D are all closed and E is open. The oil ports O1 and O2 of the hydraulic drive unit are in a closed state. Due to the large volume modulus of the oil, the mover of the hydraulic drive unit is in a near-locked state. The oil ports X and Y of the hydraulic actuator are connected to each other under the action of the high-speed switching valve E. The piston of the actuator only needs to overcome the damping force to achieve free left and right follow-up.

[0037] Furthermore, the hydraulic actuator remains locked in a certain position, the hydraulic drive unit stops moving, and all high-speed switching valves are set to the closed state. At this time, the cylinder oil port X and oil port Y of the hydraulic actuator are both in a closed cut-off state, forming a hydraulic lock. The hydraulic actuator achieves constant position output without power input, improving the actuator's energy efficiency.

[0038] Furthermore, there are two or more hydraulic power modules, and all hydraulic power modules are connected to the hydraulic actuator in parallel.

[0039] Furthermore, the present invention also provides a control method for an electro-hydraulic actuation system, comprising the following steps:

[0040] When the hydraulic actuator needs to move in the direction of the piston chamber at port Y, the hydraulic drive unit, according to the control signal, first moves in the opposite direction of the required movement. Oil flows out through port O1 of the hydraulic drive unit. At this time, high-speed switching valves A and D open, while B and C close. Pressurized oil enters through port X of the hydraulic actuator unit, pushing the piston of the actuator unit in the required movement direction. Oil flows out through port Y of the hydraulic actuator unit and enters the hydraulic drive unit through port O2. Then, according to the control signal, the hydraulic drive unit moves in the required movement direction again. Oil flows out through port O2. At this time, high-speed switching valves A and D close, while B and C open. Pressurized oil enters the hydraulic actuator unit through port X, pushing the piston of the actuator unit in the required movement direction. Oil flows out through port Y of the hydraulic actuator unit and enters the hydraulic drive unit through port O1.

[0041] When the hydraulic actuator needs to move in the direction of the piston chamber located at port X, the hydraulic drive unit moves in the desired direction according to the control signal. The oil flows out through port O1. At this time, the high-speed switching valves A and D are closed and B and C are open. The pressurized oil enters through port Y of the hydraulic actuator, pushing the piston of the actuator to move in the desired direction. The oil flows out through port X and enters the hydraulic drive unit through port O2. The hydraulic drive unit moves in the opposite direction according to the control signal. The oil flows out through port O2. At this time, the high-speed switching valves A and D are open and B and C are closed. The pressurized oil enters the hydraulic actuator through port Y, pushing the piston of the actuator to move in the desired direction. The oil flows out through port X and enters the hydraulic drive unit through port O1.

[0042] like Figure 1 As shown, the working principle of this invention is as follows:

[0043] When the double-acting hydraulic actuator needs to move to the right, the stator coil of the high-frequency linear motor receives a control current signal. Under the action of the permanent magnet, the mover of the hydraulic drive unit moves to the left, driving the piston of the reciprocating piston pump to move to the left, compressing the left piston chamber of the reciprocating piston pump. The pressure in this chamber increases, forcing the oil to flow out through port O1 of the reciprocating piston pump cylinder. At this time, the high-speed switching valves A and D open and B and C close. The pressurized oil enters the left piston chamber of the hydraulic actuator unit through port X of the double-acting hydraulic actuator unit cylinder. The pressure in this chamber increases, breaking the piston force balance of the actuator unit and pushing the piston of the actuator unit to move to the right. The oil in the right piston chamber of the actuator unit flows out through port Y of the actuator unit cylinder. This part of the oil enters the right piston chamber of the piston pump through port O2 of the reciprocating piston pump cylinder, replenishing the excess volume in the right piston chamber of the piston pump caused by the leftward movement of the piston.

[0044] The stator coil of the high-frequency linear motor receives the control current signal. Under the action of the permanent magnet, the mover of the hydraulic drive unit moves to the right, driving the reciprocating pump piston to move to the right, compressing the right piston chamber of the reciprocating piston pump. The pressure in this chamber increases, forcing the oil to flow out through port O2 of the reciprocating piston pump cylinder. At this time, the high-speed switching valves A and D are closed and B and C are open. The pressurized oil enters the left piston chamber of the hydraulic actuator unit through port X of the double-acting hydraulic actuator unit cylinder. The pressure in this chamber increases, breaking the piston force balance of the actuator unit and pushing the actuator unit piston to the right. The oil in the right piston chamber of the actuator unit flows out through port Y of the actuator unit cylinder. This part of the oil enters the left piston chamber of the reciprocating piston pump through port O1 of the reciprocating piston pump cylinder, replenishing the excess volume in the left piston chamber of the reciprocating piston pump caused by the rightward movement of the reciprocating pump piston.

[0045] When the frequency of the high-frequency linear motor driving the movement of the hydraulic drive unit is consistent with the opening and closing control frequency of the high-speed switching valve group, the reciprocating hydraulic drive unit will continuously inject pressurized oil into the oil port X of the double-acting hydraulic actuator through the distribution unit, driving the piston rod of the actuator to move to the right.

[0046] When the double-acting hydraulic actuator needs to move to the left, the stator coil of the high-frequency linear motor receives a control current signal. Under the action of the permanent magnet, the mover of the hydraulic drive unit moves to the left, driving the reciprocating pump piston to move to the left, compressing the left piston chamber of the reciprocating piston pump. The pressure in this chamber increases, forcing the oil to flow out through port O1 of the reciprocating piston pump cylinder. At this time, high-speed switching valves A and D are closed and B and C are open. Pressurized oil enters the right piston chamber of the hydraulic actuator unit through port Y of the double-acting hydraulic actuator unit cylinder. The pressure in this chamber increases, breaking the piston force balance of the actuator unit and pushing the actuator unit piston to the left. The oil in the left piston chamber of the actuator unit flows out through port X of the actuator unit cylinder. This part of the oil enters the right piston chamber of the reciprocating piston pump through port O2 of the reciprocating piston pump cylinder, replenishing the excess volume in the right piston chamber of the reciprocating piston pump caused by the leftward movement of the reciprocating pump piston.

[0047] The stator coil of the high-frequency linear motor receives the control current signal. Under the action of the permanent magnet, the mover of the hydraulic drive unit moves to the right, driving the reciprocating pump piston to move to the right, compressing the right piston chamber of the reciprocating piston pump. The pressure in this chamber increases, forcing the oil to flow out through port O2 of the reciprocating piston pump cylinder. At this time, the high-speed switching valves A and D open and B and C close. The pressurized oil enters the right piston chamber of the hydraulic actuator unit through port Y of the double-acting hydraulic actuator unit cylinder. The pressure in this chamber increases, breaking the piston force balance of the actuator unit and pushing the actuator unit piston to the left. The oil in the left piston chamber of the actuator unit flows out through port X of the actuator unit cylinder. This part of the oil enters the left piston chamber of the reciprocating piston pump through port O1 of the reciprocating piston pump cylinder, replenishing the excess volume in the left piston chamber of the reciprocating piston pump caused by the rightward movement of the reciprocating pump piston.

[0048] When the frequency of the high-frequency linear motor driving the movement of the hydraulic drive unit is consistent with the opening and closing control frequency of the high-speed switching valve group, the reciprocating hydraulic drive unit will continuously inject pressurized oil into the oil port Y of the double-acting hydraulic actuator through the distribution unit, driving the piston rod of the actuator to move to the left.

[0049] This invention relates to a high-precision, high-dynamic electro-hydraulic actuator based on a high-frequency linear motor and a high-speed switching valve. Compared to electro-hydraulic actuators that use a servo motor-bidirectional axial piston pump as a power source, this invention connects the linear motor mover to one end of the reciprocating pump piston rod, and the suction and discharge actions of the reciprocating piston pump are synchronously driven by the linear motor mover. From a structural principle perspective, all moving parts in the system undergo linear reciprocating motion, all forces are along the axial direction, there are no complex intermediate transmission links, no motion conversion links, and no introduction of lateral forces. The frictional forces that need to be overcome during motion are smaller, resulting in higher mechanical efficiency and a longer service life. The reciprocating piston pump has no rotating friction pairs, eliminating the risk of friction pair oil film failure and significantly improving reliability. Without large-inertia rotating parts, the reciprocating motion of the actuator cylinder can be achieved solely through the logic control of the high-speed switching valve group, resulting in low inertia and fast response speed.

[0050] The hydraulic drive unit of this invention has a small moment of inertia, and the system's frequency response is theoretically only related to the frequency response of the linear motor and the high-speed switching valve. Existing linear motors and high-speed switching valves all have frequency responses above 50Hz, meaning that the theoretical frequency response of the linear drive electro-hydraulic actuator with high-speed switching valve distribution can reach above 50Hz, exhibiting a significant advantage in rapid response.

[0051] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0052] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0053] like Figure 1 As shown, this example structure comprises three parts: a reciprocating hydraulic drive unit, a flow distribution unit, and a double-acting hydraulic actuator unit. The reciprocating hydraulic drive unit functions similarly to a motor-hydraulic pump unit in a hydraulic system, responsible for providing pressurized hydraulic fluid. The flow distribution unit functions similarly to a servo valve in a hydraulic system, responsible for controlling the flow direction of the hydraulic fluid. The double-acting hydraulic actuator unit adopts a double-acting symmetrical hydraulic cylinder structure. The piston on both sides of the actuator unit has the same area. When the piston moves, the flow rate at port X of the actuator unit cylinder remains consistent with the flow rate at port Y, meaning the flow rate in the left and right piston chambers of the actuator unit is conserved.

[0054] like Figure 2As shown, in this example of a reciprocating hydraulic drive unit, the linear motor mover and the reciprocating pump piston rod are fixedly connected by a coupling. When the linear motor stator coil reciprocates left and right under the action of the control current, it drives the reciprocating pump piston to perform reciprocating motion of the same amplitude and frequency within the reciprocating pump cylinder. The left and right sides of the reciprocating pump piston have the same area. When the reciprocating pump piston moves, the flow rate at port O1 and port O2 of the reciprocating pump cylinder remains consistent, meaning that the flow rates in the left and right piston chambers of the reciprocating pump are conserved.

[0055] In this example, the flow rate of oil drawn in / discharged through the reciprocating pump cylinder port of the reciprocating hydraulic drive unit is the same as the flow rate flowing out / in through the cylinder port of the double-acting hydraulic actuator. That is, the oil flow rate inside the actuator is conserved and no external oil source is required for replenishment.

[0056] When this instance is in working condition, it follows Figure 4 The four-quadrant working mode is shown, in which the rightward movement of the moving part is the positive direction.

[0057] When this example is operating in the first quadrant, high-speed switching valves B and C are open, and the hydraulic drive unit mover moves to the right. The oil in the right piston chamber of the reciprocating piston pump enters the left piston chamber of the double-acting hydraulic actuator through port O2, high-speed switching valve C, and port X, pushing the actuator piston to move to the right. The oil in the right piston chamber of the actuator enters the left piston chamber of the reciprocating piston pump through port Y, high-speed switching valve B, and port O1, replenishing the excess volume in the left piston chamber caused by the rightward movement of the reciprocating pump piston.

[0058] When this example is operating in the second quadrant, high-speed switching valves A and D are open, and the hydraulic drive unit mover moves to the right. The oil in the right piston chamber of the reciprocating piston pump enters the right piston chamber of the double-acting hydraulic actuator unit through port O2, high-speed switching valve D, and port Y, pushing the actuator piston to the left. The oil in the left piston chamber of the actuator unit enters the left piston chamber of the reciprocating piston pump through port X, high-speed switching valve A, and port O1, replenishing the excess volume in the left piston chamber caused by the rightward movement of the reciprocating pump piston.

[0059] When this example operates in the third quadrant, high-speed switching valves B and C are open, and the hydraulic drive unit mover moves to the left. The oil in the left piston chamber of the reciprocating piston pump enters the right piston chamber of the double-acting hydraulic actuator through port O1, high-speed switching valve B, and port Y, pushing the actuator piston to move to the left. The oil in the left piston chamber of the actuator enters the right piston chamber of the reciprocating piston pump through port X, high-speed switching valve C, and port O2, replenishing the excess volume in the right piston chamber caused by the leftward movement of the reciprocating pump piston.

[0060] When this example operates in the fourth quadrant, high-speed switching valves A and D are open, and the hydraulic drive unit mover moves to the left. The oil in the left piston chamber of the reciprocating piston pump enters the left piston chamber of the double-acting hydraulic actuator unit through port O1, high-speed switching valve A, and port X, pushing the actuator piston to the right. The oil in the right piston chamber of the actuator unit enters the right piston chamber of the reciprocating piston pump through port Y, high-speed switching valve D, and port O2, replenishing the excess volume in the right piston chamber caused by the leftward movement of the reciprocating pump piston.

[0061] Specifically, in this example, when the double-acting hydraulic actuator needs to be locked in a certain position, the high-frequency linear motor stops moving and the high-speed switching valves are all set to the closed state. At this time, the cylinder oil port X and oil port Y of the double-acting hydraulic actuator are both in a closed cut-off state, forming a hydraulic lock. The double-acting hydraulic actuator achieves constant position output without power input, improving the actuator's energy efficiency.

[0062] In this example, when not in operation, the high-frequency linear motor has no current input signal and does not output motion. When all high-speed switching valves are closed, the double-acting hydraulic actuator is locked at its initial zero position. When high-speed switching valve E is open and other valves are closed, the linear drive electro-hydraulic actuator distributed by the high-speed switching valve is in... Figure 6 As shown in the follow-up working state, the left piston chamber and the right piston chamber of the double-acting hydraulic actuator are connected. The piston of the actuator only needs to overcome the damping force to achieve free left and right movement within the actuator cylinder.

[0063] The on / off logic of the high-speed switching valve under different states in this example is as follows: Figure 5 As shown, the position output of the actuator can be achieved by combining it with the four-quadrant working mode of the actuator.

[0064] In this example, the reciprocating hydraulic drive unit and the distribution unit can be integrated into... Figure 3 The hydraulic power module shown. Figure 7 This mode allows for the parallel operation of multiple hydraulic power modules. In this mode, if multiple hydraulic power modules work synchronously, the actuator's output power can be multiplied. If only some hydraulic power modules work, the remaining hydraulic power modules can serve as backup modules, achieving redundancy configuration and improving the actuator's reliability.

[0065] This invention achieves oil suction and discharge functions similar to a hydraulic pump through the high-frequency reciprocating motion of the mover in a reciprocating hydraulic drive unit; it regulates the oil flow direction into and out of the double-acting hydraulic actuator through the opening and closing logic of the high-speed switching valve in the distribution unit; and it achieves the desired position output through the movement of the piston in the double-acting hydraulic actuator. The high-frequency response characteristics of the high-frequency linear motor and the high-speed switching valve ensure the actuator's rapid response capability; the simple control logic and redundancy configuration method ensure the actuator's reliability; and the digital signal control method simplifies the controller hardware structure. This invention provides stable and reliable control and has wide applications.

[0066] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

[0067] The parts of this invention not described in detail are techniques known to those skilled in the art.

Claims

1. An electro-hydrostatic actuation system, characterized by: It includes at least one hydraulic power module and a hydraulic actuator, wherein the hydraulic power module provides the power for the movement of the hydraulic actuator; The hydraulic power module includes a hydraulic drive unit and a distribution unit. The hydraulic drive unit reciprocates according to the received control signal, causing its two oil ports O1 and O2 to alternately generate pressurized oil. The pressurized oil is then delivered to the two oil ports X and Y of the hydraulic actuator through the opening and closing logic control of the distribution unit, causing the hydraulic actuator to move. The flow distribution unit includes at least four high-speed switching valves, wherein one side of switching valves A and B is connected to the oil port O1 of the hydraulic drive unit, one side of switching valves C and D is connected to the oil port O2 of the hydraulic drive unit, the other side of switching valves A and C is connected to the oil port X of the hydraulic actuator unit, and the other side of switching valves B and D is connected to the oil port Y of the hydraulic actuator unit. The opening and closing logic control of the high-speed switching valve of the flow distribution unit is as follows: When the hydraulic actuator needs to move towards the piston chamber located at port Y, the hydraulic drive unit first moves in the opposite direction of the required movement direction. At this time, high-speed switching valves A and D open and B and C close. Then, the hydraulic drive unit moves in the required movement direction, at which time high-speed switching valves A and D close and B and C open. When the hydraulic actuator needs to move towards the piston chamber located at port X, the hydraulic drive unit first moves in the required movement direction. At this time, high-speed switching valves A and D close and B and C open. Then, the hydraulic drive unit moves in the opposite direction of the required movement direction, at which time high-speed switching valves A and D open and B and C close.

2. An electro-hydrostatic actuation system according to claim 1, characterized in that: The frequency of the hydraulic drive unit's movement is consistent with the opening and closing control frequency of the high-speed switching valve group. The reciprocating motion of the hydraulic drive unit will continuously inject pressurized oil into the oil port X or Y of the hydraulic actuator unit through the distribution unit, driving the piston rod of the hydraulic actuator unit to move continuously in a certain direction.

3. An electro-hydrostatic actuation system according to claim 1, characterized in that: The flow distribution unit also includes a switching valve E, which is connected to the hydraulic actuator port X and port Y on both sides, respectively. When the hydraulic actuator does not need to output motion and is in a follow-up state, the hydraulic drive unit does not generate motion, and at this time, high-speed switching valves A, B, C, and D are all closed and E is open.

4. The electro-hydraulic actuation system according to claim 3, characterized in that: The hydraulic actuator is locked in a certain position, the hydraulic drive unit stops moving, and all high-speed switching valves are set to the closed state.

5. The electro-hydraulic actuation system according to claim 1, characterized in that: The hydraulic drive unit includes a linear motor and a piston pump. The piston pump cylinder consists of two independent chambers, with oil ports O1 and O2 respectively located on different chambers. The mover of the linear motor is fixedly connected to the piston of the piston pump. The linear motor receives current signals from the controller and drives the piston of the piston pump to reciprocate, thereby generating pressurized oil alternately at the two oil ports O1 and O2 of the piston pump. The hydraulic actuation unit includes an actuation unit cylinder and an actuation unit piston. The actuation unit cylinder includes two independent piston chambers, with oil ports X and Y respectively located on different chambers.

6. The electro-hydraulic actuation system according to claim 5, characterized in that: The piston pump has the same area on both sides of the piston, and the hydraulic actuator has the same area on both sides of the piston.

7. The electro-hydraulic actuation system according to claim 1, characterized in that: The hydraulic power module consists of two or more units, and all hydraulic power modules are connected to the hydraulic actuator in parallel.

8. A control method for an electro-hydraulic actuation system, characterized in that, Includes the following steps: When the hydraulic actuator needs to move in the direction of the piston chamber at port Y, the hydraulic drive unit, according to the control signal, first moves in the opposite direction of the required movement. Oil flows out through port O1 of the hydraulic drive unit. At this time, high-speed switching valves A and D open, while B and C close. Pressurized oil enters through port X of the hydraulic actuator unit, pushing the piston of the actuator unit in the required movement direction. Oil flows out through port Y of the hydraulic actuator unit and enters the hydraulic drive unit through port O2. Then, according to the control signal, the hydraulic drive unit moves in the required movement direction again. Oil flows out through port O2. At this time, high-speed switching valves A and D close, while B and C open. Pressurized oil enters the hydraulic actuator unit through port X, pushing the piston of the actuator unit in the required movement direction. Oil flows out through port Y of the hydraulic actuator unit and enters the hydraulic drive unit through port O1. When the hydraulic actuator needs to move in the direction of the piston chamber located at port X, the hydraulic drive unit moves in the desired direction according to the control signal. The oil flows out through port O1. At this time, the high-speed switching valves A and D are closed and B and C are open. The pressurized oil enters through port Y of the hydraulic actuator, pushing the piston of the actuator to move in the desired direction. The oil flows out through port X and enters the hydraulic drive unit through port O2. The hydraulic drive unit moves in the opposite direction according to the control signal. The oil flows out through port O2. At this time, the high-speed switching valves A and D are open and B and C are closed. The pressurized oil enters the hydraulic actuator through port Y, pushing the piston of the actuator to move in the desired direction. The oil flows out through port X and enters the hydraulic drive unit through port O1.

9. The control method for an electro-hydraulic actuation system according to claim 8, characterized in that: The frequency of the hydraulic drive unit's movement is consistent with the opening and closing control frequency of the high-speed switching valve group. The reciprocating motion of the hydraulic drive unit will continuously inject pressurized oil into the oil port X or Y of the hydraulic actuator unit through the distribution unit, driving the piston rod of the hydraulic actuator unit to move continuously in a certain direction.

10. The control method for an electro-hydraulic actuation system according to claim 8, characterized in that: When the hydraulic actuator does not need to output motion and is in a follow-up state, the hydraulic drive unit does not generate motion, and at this time, high-speed switching valves A, B, C, and D are all closed and E is open; when the hydraulic actuator remains locked in a certain position, the hydraulic drive unit stops moving, and all high-speed switching valves are set to the closed state.

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