Self-redundancy multi-stage actuator system for wind tunnel attack angle mechanism

Abstract

The invention relates to the technical field of wind tunnels, and discloses a self-redundancy multistage actuator system for a wind tunnel attack angle mechanism, which comprises an actuator body hinged to an actuator base, the actuator body is provided with a piston rod group connected with a test model supporting structure, and the piston rod group is simultaneously in transmission connection with a servo motor and a hydraulic driving mechanism. The system adopts a double-source fusion structure of cooperative work of electric drive and hydraulic drive, the servo motor realizes high-precision position control, the hydraulic drive mechanism provides high-power output and dynamic load compensation, and respective rated power requirements of the servo motor and the hydraulic drive mechanism can be reduced in a power division mode. The hydraulic driving mechanism adopts a proportional valve or a switch valve to carry out power following control, and a traditional servo valve is not needed. The double-source fusion structure has heterogeneous self-redundancy capability, and can still maintain the driving function when any driving source is subjected to performance degradation. The system has high-precision control, high dynamic performance and high reliability, and is suitable for high-thrust and high-precision attitude adjustment requirements of a wind tunnel angle-of-attack mechanism.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wind tunnel technology, in particular to a self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism. BACKGROUND

[0002] A wind tunnel is an experimental device that artificially generates and controls airflow to simulate the aerodynamic state around an aircraft or entity, widely used in aerospace, automotive, and architectural fields. It is an important ground facility for aerodynamic characteristic research, performance verification, and optimization. In wind tunnel testing, to accurately simulate the attitude changes of an aircraft in different flight states, especially the adjustment of the angle of attack, the angle-of-attack mechanism needs to drive and position the test model installed at the front end of the support structure (such as a curved knife support plate) with high precision.

[0003] In the wind tunnel angle-of-attack mechanism, to meet the requirements of large thrust and long stroke, a double-stage actuator is often used with a double-actuator parallel / symmetrical driving arrangement. This structure requires strict synchronization control during operation: the two actuators should be extended / retracted at the same rate throughout the stroke range, allowing the support structure (such as the curved knife support plate and the model mounting end) to move in a predetermined kinematic relationship, avoiding additional lateral forces and torques caused by inconsistent displacement; at the same time, the displacement distribution and speed matching between the two stages should be ensured to prevent jamming, uneven loading, and structural deformation, ensuring the angle-of-attack positioning accuracy, dynamic response, and static holding stiffness. If the synchronization error exceeds the limit, it will cause attitude deviation of the support structure, unbalanced load distribution, and even mechanical interference, affecting the consistency of test data and system safety.

[0004] Existing angle-of-attack mechanisms mostly use multi-stage servo hydraulic cylinders as the main actuator to meet the requirements of large thrust and long stroke for driving large models in large wind tunnels. However, the servo hydraulic driving method has several limitations: first, the servo valve is expensive and complex in structure, highly sensitive to oil cleanliness, and has insufficient reliability, resulting in high maintenance costs; second, the servo hydraulic cylinder itself cannot provide effective redundancy, and once the main oil line or servo valve fails, the angle-of-attack mechanism will lose driving capability, severely affecting the continuity and safety of wind tunnel testing; in addition, the traditional hydraulic system has high energy consumption and requires a large amount of oil, still facing limitations in space arrangement and environmental protection.

[0005] On the other hand, while electromechanical actuators offer advantages such as fast response and high control precision, existing actuators still suffer from insufficient thrust, low power density, and large overall size in applications like angle-of-attack mechanisms that require high loads and long strokes. When used to drive large wind tunnel models, their size and mass often fail to meet the spatial and dynamic performance requirements of the support structure. Furthermore, electric drive systems typically lack redundancy; a failure in the motor or transmission system can also lead to angle-of-attack control failure.

[0006] In summary, existing angle-of-attack mechanisms based on servo hydraulic cylinders or pure electromechanical actuators all suffer from shortcomings in simultaneously achieving high thrust, high precision, high reliability, and structural compactness. Therefore, there is an urgent need to provide an angle-of-attack mechanism that possesses high precision, high dynamic performance, redundancy capabilities, lower cost, and higher reliability to meet the development needs of next-generation wind tunnel testing. Summary of the Invention

[0007] The purpose of this invention is to provide a self-redundant multi-stage actuator system for wind tunnel angle-of-attack mechanisms to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides a self-redundant multi-stage actuator system for wind tunnel angle-of-attack mechanisms, comprising: The actuator body is hinged to the actuator base. The actuator body has a piston rod assembly, which is connected to the test model support structure. The piston rod assembly is also connected to the servo motor and the hydraulic drive mechanism.

[0009] Furthermore, the actuator body includes: The first-stage cylinder has a first piston nut assembly internally sealed and slidably connected. The piston rod assembly includes a first piston rod and a second piston rod. The first piston rod is disposed in the first-stage cylinder and is circumferentially rotatably connected to the first piston nut assembly. The first piston rod and the first piston nut assembly divide the first-stage cylinder into a first rod chamber and a first rodless chamber. The reducer is located at the end of the first-stage cylinder. Its power input end is connected to the servo motor, and its power output end is provided with a trapezoidal lead screw. The trapezoidal lead screw passes through the first rodless cavity and is threadedly connected to the first piston nut pair. The first piston rod has a cavity inside, and the trapezoidal lead screw extends into the cavity and maintains a synchronous rotation relationship with the first piston rod. A secondary cylinder is disposed within the first rod chamber and fixedly connected to the first piston nut assembly. A second piston nut assembly is fixedly disposed at the tail end of the second piston rod. The second piston nut assembly is slidably connected to the secondary cylinder in a sealed manner. The second piston rod and the second piston nut assembly divide the secondary cylinder into a second rod chamber and a second rodless chamber. The first piston rod has a trapezoidal thread on its exterior and is threadedly connected to the second piston nut assembly. The second piston rod is connected to the test model support structure. The servo motor drives the first piston rod and the second piston rod to perform proportional linear motion. The first rod-type chamber, the first rodless chamber, the second rod-type chamber, and the second rodless chamber are all connected to the hydraulic drive mechanism.

[0010] Furthermore, the hydraulic drive mechanism includes: The monitoring unit is connected to the first rod chamber, the first rodless chamber, the second rod chamber, and the second rodless chamber, and is used to monitor the pressure in real time. A constant pressure power unit is connected to the first rod chamber, the first rodless chamber, the second rod chamber, and the second rodless chamber, and is used to provide hydraulic pressure. The control unit is connected to the monitoring unit and the constant pressure power unit respectively, and is used to control the oil pressure of the first rod chamber, the first rodless chamber, the second rod chamber and the second rodless chamber, and to ensure the realization of redundancy functions.

[0011] Furthermore, the monitoring unit includes: The first pressure sensor is connected to the first rodless cavity and the second rodless cavity respectively; The second pressure sensor is connected to both the first rod chamber and the second rod chamber.

[0012] Furthermore, the control unit includes: The first three-position four-way proportional valve has an oil inlet connected to the constant pressure power unit and an oil return port connected to the oil tank. Its working oil ports include working oil port A and working oil port B. Working oil port B is blocked. Working oil port A is connected to the oil inlet of the cartridge valve. The oil outlet of the cartridge valve is connected to the first pressure sensor, the first safety valve, the first rodless chamber and the second rodless chamber respectively. The second three-position four-way proportional valve has an oil inlet connected to the constant pressure power unit and an oil return port connected to the oil tank. Its working oil ports include working oil port C and working oil port D. Working oil port D is blocked. Working oil port C is connected to the second pressure sensor, the oil outlet of the replenishing check valve, the oil inlet of the second safety valve, the first rod chamber and the second rod chamber respectively. The replenishing check valve is located close to the first rod chamber and the second rod chamber. The second switching valve connects the outlet of the cartridge valve to the working port C of the second three-position four-way proportional valve, and dynamically manages the participation status of the hydraulic drive mechanism based on a set pressure threshold.

[0013] Furthermore, the cartridge valve is a cone valve structure with an active control cover.

[0014] Furthermore, the constant pressure power unit includes: a first accumulator group, a switching valve, a filter, a check valve, a constant pressure valve, a motor, a variable pump, a variable piston cylinder, a relief valve, a second accumulator group, and a third pressure sensor; The electric motor drives the variable pump. The constant pressure valve detects the outlet pressure of the variable pump and controls the movement of the valve core. The two working ports at one end of the constant pressure valve are connected to the outlet of the variable pump and the oil tank, respectively. The working port at the other end is connected to the rodless chamber of the variable piston cylinder. The rod chamber of the variable piston cylinder is connected to the outlet of the variable pump. The constant pressure valve and the variable piston cylinder jointly adjust the swashplate angle of the variable pump to keep the actuator body in a constant pressure condition. The check valve is connected to the inlet of the relief valve and the outlet of the variable pump. The outlet of the check valve is connected to the filter. The outlet of the filter is connected to the switching valve and one end of the long connecting pipe. The switching valve is connected to the first accumulator group. The other end of the long connecting pipe is connected to the second accumulator group through a hose. The third pressure sensor is set at the inlet of the second accumulator group. The second accumulator group is connected to the inlets of the first three-position four-way proportional valve and the second three-position four-way proportional valve, respectively.

[0015] Furthermore, the first accumulator group and the second accumulator group are airbag accumulators.

[0016] The present invention discloses the following technical effects: 1. This invention employs a dual-source fusion configuration where a servo motor and a hydraulic drive mechanism collaboratively drive a piston rod assembly, forming an actuator system with heterogeneous self-redundancy capabilities. The servo motor is responsible for high-precision position control, enabling accurate positioning and trajectory tracking of the test model's support structure; the hydraulic subsystem, as a high-power output unit, provides peak load support and dynamic load compensation. When either drive source experiences performance degradation or failure, the other drive source can independently maintain basic driving capability, significantly improving the reliability of the angle-of-attack mechanism and the continuity of wind tunnel testing. Compared to traditional pure servo hydraulic cylinders or single electromechanical actuators, this invention offers significant advantages in high precision, high dynamic performance, and system reliability.

[0017] 2. The actuator of this invention adopts a power-split configuration, with the electromechanical and hydraulic subsystems respectively undertaking output tasks at different frequencies and amplitudes, thereby significantly reducing the maximum power requirements and installed power of the two types of drive units. In low-speed, small-amplitude oscillation or high-precision control scenarios, higher control accuracy and dynamic response can be achieved by using the servo motor as the main driver and the hydraulic system providing low-power compensation; in high-load or rapid attitude change scenarios, the hydraulic subsystem provides high-power output, realizing the complementary advantages of electro-hydraulic systems and comprehensively improving the dynamic performance and stability of the angle-of-attack mechanism.

[0018] 3. The hydraulic subsystem of this invention uses proportional valves or on / off valves instead of traditional servo valves to achieve follow-up control of hydraulic power output, eliminating the need for expensive, complex, and unreliable servo valve components. Thanks to the redundancy and division of labor strategy provided by the dual-source fusion mechanism, the hydraulic subsystem no longer undertakes high-precision positioning functions, but mainly handles high-power output and holding functions, thereby effectively reducing the accuracy requirements of the hydraulic system. This allows the invention to utilize lower-cost, more contamination-resistant commercial hydraulic modules.

[0019] 4. After the test model reaches the preset angle of attack, the hydraulic drive mechanism can maintain internal pressure to achieve position locking, thereby significantly reducing the static load on the servo motor and improving its service life; at the same time, it reduces the continuous high-load operation time of the hydraulic system, extending the life cycle of consumable parts such as hydraulic oil, seals, and filters. This self-redundancy strategy not only improves the overall energy efficiency of the system, but also fundamentally reduces the dependence of the angle-of-attack mechanism on high-cost precision hydraulic technology, achieving comprehensive optimization of manufacturing and maintenance costs. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Fig. 1 This is a schematic diagram of the structure of the present invention; Fig. 2 This is a schematic diagram of the actuator body structure; Fig. 3 This is a schematic diagram showing the connection between the actuator body and the support structure of the test model; The components include: 1. First accumulator group; 2. First switching valve; 3. Filter; 4. Check valve; 5. Constant pressure valve; 6. Electric motor; 7. Variable pump; 8. Variable piston cylinder; 9. Relief valve; 10. Second accumulator group; 11. Third pressure sensor; 12. Cartridge valve; 13. First pressure sensor; 14. First three-position four-way proportional valve; 15. First safety valve; 16. Second pressure sensor; 17. Second three-position four-way proportional valve; 18. Second switching valve; 19. Replenishment check valve. ; 20. Second safety valve; 21. Actuator body; 22. Reducer; 23. Trapezoidal lead screw; 24. First stage cylinder; 25. First piston nut pair; 26. Rotary shaft lip seal ring; 27. First piston rod; 28. Second piston nut pair; 29. ​​Second stage cylinder; 30. Second piston rod; 31. Servo motor; 32. First rodless chamber; 33. First rod chamber; 34. Second rodless chamber; 35. Second rod chamber; 36. Test model support structure; 37. Actuator base. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figs. 1 to 3 As shown, this embodiment of the invention provides a self-redundant multi-stage actuator system for wind tunnel angle-of-attack mechanisms, comprising: The actuator body 21 is hinged to the actuator base 37. The actuator body 21 has a piston rod assembly, which is connected to the test model support structure 36. The piston rod assembly is also connected to the servo motor 31 and the hydraulic drive mechanism.

[0025] In this embodiment, the test model support structure 36 is a curved blade support plate.

[0026] In this embodiment, the actuator body 21 includes: The first-stage cylinder 24 has a first piston nut pair 25 internally sealed and slidably connected. The piston rod assembly includes a first piston rod 27 and a second piston rod 30. The first piston rod 27 is disposed in the first-stage cylinder 24 and is circumferentially connected to the first piston nut pair 25 through a rotating shaft lip seal ring 26. The first piston rod 27 and the first piston nut pair 25 divide the first-stage cylinder 24 into a first rod chamber 33 and a first rodless chamber 32. In this embodiment, the actuator body 21 has a sealing groove on its inner wall near the end face of the first piston rod 27, and a rotating shaft lip seal ring 26 is installed in the sealing groove. The seal ring has two sealing lips spaced apart from each other, forming a filling cavity between the two sealing lips, and a barrier grease is injected into the filling cavity to enhance the sealing performance and prevent oil leakage along the mating gap.

[0027] The reducer 22 is located at the end of the first stage cylinder 24. Its power input end is connected to the servo motor 31, and its power output end is provided with a trapezoidal lead screw 23. The trapezoidal lead screw 23 has a guide groove on its outside. The trapezoidal lead screw 23 passes through the first rodless cavity 32 and is threadedly connected to the first piston nut pair 25. The first piston rod 27 has a cavity inside and a guide key. The trapezoidal lead screw 23 extends into the cavity and maintains a synchronous rotation relationship with the first piston rod through the cooperation of the guide key and the guide groove. The secondary cylinder 29 is disposed within the first rod chamber 33 and fixedly connected to the first piston nut assembly 25 via a sealing flange. The tail of the second piston rod 30 is fixedly provided with a second piston nut assembly 28, which is in a sealed sliding connection with the secondary cylinder 29. The second piston rod 30 and the second piston nut assembly 28 divide the secondary cylinder 29 into a second rod chamber 35 and a second rodless chamber 34. The exterior of the first piston rod 27 is provided with a trapezoidal thread and is threadedly connected to the second piston nut assembly 28. The pitch of the trapezoidal screw 23 is different from the pitch of the trapezoidal thread on the exterior of the first piston rod 27. The second piston rod 30 is connected to the test model support structure 36. The servo motor 31 drives the first piston rod 27 and the second piston rod 30 to perform proportional linear motion. The first rod chamber 33, the first rodless chamber 32, the second rod chamber 35, and the second rodless chamber 34 are all connected to the hydraulic drive mechanism, and drive the first piston rod 27 and the second piston rod 30 to produce proportional linear motion through the servo motor 31 and the hydraulic drive mechanism.

[0028] In this embodiment, the hydraulic drive mechanism includes: The monitoring unit is connected to the first rod chamber 33, the first rodless chamber 32, the second rod chamber 35, and the second rodless chamber 34, and is used to monitor the pressure in real time. The constant pressure power unit is connected to the first rod chamber 33, the first rodless chamber 32, the second rod chamber 35, and the second rodless chamber 34, and is used to provide oil pressure and compensate for the flow of the actuator system; The control unit is connected to the monitoring unit and the constant pressure power unit respectively. It is used to control the oil pressure of the first rod chamber 33, the first rodless chamber 32, the second rod chamber 35 and the second rodless chamber 34, thereby adjusting the maximum output power of the actuator system and eliminating the hydraulic shock generated when the system experiences a large flow change. At the same time, it can control the degree of participation of the hydraulic subsystem according to the working requirements, so as to selectively enable or disable the redundancy capability of the actuator.

[0029] In this embodiment, the monitoring unit includes: The first pressure sensor 13 is connected to the first rodless cavity 32 and the second rodless cavity 34 respectively; The second pressure sensor 16 is connected to the first rod chamber 33 and the second rod chamber 35 respectively.

[0030] In this embodiment, the control unit includes: The first three-position four-way proportional valve 14 has an oil inlet connected to the constant pressure power unit and an oil return port connected to the oil tank. Its working oil ports include working oil port A and working oil port B. Working oil port B is blocked. Working oil port A is connected to the oil inlet of cartridge valve 12. The oil outlet of cartridge valve 12 is connected to the first pressure sensor 13, the first safety valve 15, the first rodless chamber 32 and the second rodless chamber 34, respectively. The second three-position four-way proportional valve 17 has an oil inlet connected to the constant pressure power unit and an oil return port connected to the oil tank. Its working oil ports include working oil port C and working oil port D. Working oil port D is blocked. Working oil port C is connected to the second pressure sensor 16, the oil outlet of the replenishing oil check valve 19, the oil inlet of the second safety valve 20, the first rod chamber 33 and the second rod chamber 35 respectively. The replenishing oil check valve 19 is set close to the first rod chamber 33 and the second rod chamber 35. The second switching valve 18 connects the oil outlet of the cartridge valve to the working oil port C of the second three-position four-way proportional valve. Taking the pressure threshold control logic as an example, the heterogeneous self-redundant working process of this system is as follows: when the actuator output pressure or load pressure reaches the preset upper limit threshold, the second switching valve 18 remains closed, and the hydraulic drive mechanism intervenes to provide additional power; when the pressure is in the normal working range and below the lower limit threshold, the second switching valve 18 opens, the hydraulic drive mechanism remains in standby, and the actuator body 21 is driven only by the servo motor 31 to reduce energy consumption.

[0031] It should be noted that each three-position four-way proportional valve has two working ports. The working ports A, B, C and D mentioned above are only for distinguishing different working ports and are not specially set working ports.

[0032] In this embodiment, the constant pressure power unit includes: a first accumulator group 1, a first switching valve 2, a filter 3, a one-way valve 4, a constant pressure valve 5, an electric motor 6, a variable pump 7, a variable piston cylinder 8, an overflow valve 9, a second accumulator group 10, and a third pressure sensor 11. The electric motor 6 drives the variable pump 7. The constant pressure valve 5 detects the outlet pressure of the variable pump 7 and controls the movement of the valve core. Two working ports at one end of the constant pressure valve 5 are connected to the outlet of the variable pump 7 and the oil tank, respectively. The working port at the other end is connected to the rodless chamber of the variable piston cylinder 8. The rod chamber of the variable piston cylinder 8 is connected to the outlet of the variable pump 7. The constant pressure valve 5 and the variable piston cylinder 8 together adjust the swashplate angle of the variable pump 7, keeping the actuator body 21 under constant pressure. The check valve 4 and the relief valve 9 have their inlets and outlets connected to the pump 7. The outlet of the variable pump 7 is connected to the filter 3, the outlet of the check valve 4 is connected to the filter 3, the outlet of the filter 3 is connected to the first switching valve 2 and one end of the long connecting pipe, the first switching valve 2 is connected to the first accumulator group 1, and the other end of the long connecting pipe is connected to the second accumulator group 10 through a hose. The third pressure sensor 11 is set at the inlet of the second accumulator group 10. The second accumulator group 10 is connected to the inlet of the first three-position four-way proportional valve 14 and the second three-position four-way proportional valve 17 respectively.

[0033] In this embodiment, both the first accumulator group 1 and the second accumulator group 10 are pneumatic accumulators. The first accumulator group 1 is mainly used for flow energy storage to meet the short-term high flow rate requirements of the actuator system. The second accumulator group 10 is used for pressure energy storage to improve the dynamic characteristics of the system, reduce the oil pressure fluctuation during the operation of the hydraulic system, and improve the stability of the system.

[0034] The first safety valve 15 and the second safety valve 20 are used to eliminate pressure peaks in the actuator system and prevent hydraulic shock from damaging the system. The replenishing check valve 19 is only set at the inlet of the first rod chamber 33 and the second rod chamber 35 to prevent the rod chamber of the differential multi-stage cylinder from sucking in air during operation.

[0035] The cartridge valve 12 is used to keep the first rodless chamber 32 or the second rodless chamber 34 of the actuator body 21 locked. The cartridge valve 12 is a cone valve structure with an active control cover. By adjusting the opening and closing time of the cartridge valve 12 and the maximum valve core opening, the hydraulic shock generated when the actuator system experiences a large flow change is eliminated. The orifice diameters of the first three-position four-way proportional valve 14 and the second three-position four-way proportional valve 17 must be calculated and determined according to the required flow rate of each chamber in the actuator body 21.

[0036] When this embodiment is applied to a wind tunnel, the number of constant pressure power units should meet the flow requirements under normal load speed. The volume and number of the first accumulator group 1 should be determined based on the flow requirements of the wind tunnel angle-of-attack mechanism during emergency zeroing. The initial charging pressure of the second accumulator group 10 should be increased as much as possible within the allowable range to ensure a stable oil source output pressure.

[0037] In this embodiment, the tail of the actuator body 21 is fixed to the actuator base 37 by a hinge, and the other side is connected to the curved blade support plate by a hinge shaft, driving the curved blade support plate to rotate in the forward / reverse direction, thereby changing the angle of attack of the test model.

[0038] In this embodiment, the spring pressure of the constant pressure valve 5 can be set so that the outlet pressure of the constant pressure power unit is higher than the load pressure by a fixed value, thereby ensuring that the openings of the first three-position four-way proportional valve 14 and the second three-position four-way proportional valve 17 are maximized, and throttling losses are completely eliminated.

[0039] In one embodiment of the present invention, the multi-stage actuator system employs a symmetrical parallel arrangement of two actuators with synchronous control to meet the kinematic requirement of "proportional extension / retraction" when the two-stage strokes of the angle-of-attack mechanism are superimposed. Specifically, the two actuator bodies 21 extend or retract synchronously according to a preset proportional relationship throughout the adjustment process, enabling the test model support structure 36 to change its posture along a predetermined trajectory, and limiting the synchronization error to an allowable range. This avoids off-center loading, additional torque, and lateral force caused by inconsistent displacement, and reduces the risk of jamming and structural deformation.

[0040] In this embodiment, displacement synchronization and trajectory tracking are achieved through high-precision closed-loop control of servo motor 31. The hydraulic drive mechanism provides the main load and peak power output, and dynamically compensates for the load difference between the two actuator bodies 21 under high load or disturbance conditions, so as to ensure that the multi-stage actuator system still has high precision, high dynamic performance and high reliability synchronous drive capability under high thrust and long stroke conditions.

[0041] The specific work process is as follows: First, the servo motor 31 inputs a control signal to achieve precise position and speed control; then the control unit is activated, and the hydraulic drive mechanism compensates and outputs the main power.

[0042] For the servo motor 31, the output torque of the servo motor 31 is transmitted to the first piston nut pair 25 via the trapezoidal lead screw 23, thereby driving the first piston rod 27 to move linearly relative to the first stage cylinder 24. At the same time, due to the cooperation of the guide key and the guide groove, the trapezoidal lead screw 23 and the first piston rod 27 maintain a synchronous rotation relationship. The second piston nut pair 28 is threadedly connected to the first piston rod 27, and the pitch of the trapezoidal lead screw 23 is different from the pitch of the trapezoidal thread on the outside of the first piston rod 27. Therefore, the second piston rod 30 rotates relative to the first piston rod 27 and also moves linearly during rotation. However, the linear strokes of the first piston rod 27 and the second piston rod 30 are different, and the two perform reciprocating linear motion in equal proportion.

[0043] For the hydraulic drive mechanism, the oil pressure supplied by the hydraulic drive mechanism acts on both ends of the first piston nut pair 25 and the second piston nut pair 28. Through the dynamic and static pressure bearing capacity generated by the high-pressure oil film and its lubrication and drag reduction effects, it drives the first piston rod 27 and the second piston rod 30 together with the mechanical driving force of the servo motor 31. When the second piston rod 30 drives the curved blade support plate to the preset position, the control unit is turned off and the servo motor 31 is adjusted to the de-energized state. At this time, relying on the oil pressure difference between the chambers inside the actuator body 21, the actuator body 21 can maintain its self-locking function, thereby keeping the curved blade support plate in the current position.

[0044] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A self-redundant multi-stage actuator system for wind tunnel angle-of-attack mechanisms, characterized in that, include: The actuator body (21) is hinged to the actuator base (37). The actuator body (21) has a piston rod assembly, which is connected to the test model support structure (36). The piston rod assembly is also connected to the servo motor (31) and the hydraulic drive mechanism.

2. The self-redundant multi-stage actuator system for wind tunnel angle-of-attack mechanisms according to claim 1, characterized in that, The actuator body (21) includes: The first-stage cylinder (24) has a first piston nut pair (25) internally sealed and slidably connected. The piston rod assembly includes a first piston rod (27) and a second piston rod (30). The first piston rod (27) is disposed in the first-stage cylinder (24) and is circumferentially rotatably connected to the first piston nut pair (25). The first piston rod (27) and the first piston nut pair (25) divide the first-stage cylinder (24) into a first rod chamber (33) and a first rodless chamber (32). The reducer (22) is located at the end of the first stage cylinder (24). Its power input end is connected to the servo motor (31), and its power output end is provided with a trapezoidal lead screw (23). The trapezoidal lead screw (23) passes through the first rodless cavity (32) and is threadedly connected to the first piston nut pair (25). The first piston rod (27) has a cavity inside. The trapezoidal lead screw (23) extends into the cavity and rotates synchronously with the first piston rod (27). The secondary cylinder (29) is disposed in the first rod chamber (33) and fixedly connected to the first piston nut pair (25). The tail of the second piston rod (30) is fixedly provided with a second piston nut pair (28). The second piston nut pair (28) is sealed and slidably connected to the secondary cylinder (29). The second piston rod (30) and the second piston nut pair (28) divide the secondary cylinder (29) into a second rod chamber (35) and a second rodless chamber (34). The first piston rod (27) is provided with a trapezoidal thread on its outside and is threadedly connected to the second piston nut pair (28). The second piston rod (30) is connected to the test model support structure (36). The servo motor (31) drives the first piston rod (27) and the second piston rod (30) to perform proportional linear motion. The first rod chamber (33), the first rodless chamber (32), the second rod chamber (35), and the second rodless chamber (34) are all connected to the hydraulic drive mechanism.

3. A self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism according to claim 2, characterized in that, The hydraulic drive mechanism includes: The monitoring unit is connected to the first rod chamber (33), the first rodless chamber (32), the second rod chamber (35), and the second rodless chamber (34) for real-time pressure monitoring; The constant pressure power unit is connected to the first rod chamber (33), the first rodless chamber (32), the second rod chamber (35), and the second rodless chamber (34) to provide oil pressure; The control unit is connected to the monitoring unit and the constant pressure power unit respectively, and is used to control the oil pressure of the first rod chamber (33), the first rodless chamber (32), the second rod chamber (35), and the second rodless chamber (34).

4. A self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism according to claim 3, characterized in that, The monitoring unit includes: The first pressure sensor (13) is connected to the first rodless cavity (32) and the second rodless cavity (34) respectively; The second pressure sensor (16) is connected to the first rod chamber (33) and the second rod chamber (35), respectively.

5. A self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism according to claim 4, characterized in that, The control unit includes: The first three-position four-way proportional valve (14) has an oil inlet connected to the constant pressure power unit and an oil return port connected to the oil tank. Its working oil ports include working oil port A and working oil port B. Working oil port B is blocked. Working oil port A is connected to the oil inlet of the cartridge valve (12). The oil outlet of the cartridge valve (12) is connected to the first pressure sensor (13), the first safety valve (15), the first rodless chamber (32), and the second rodless chamber (34), respectively. The second three-position four-way proportional valve (17) has an oil inlet connected to the constant pressure power unit and an oil return port connected to the oil tank. Its working oil ports include working oil port C and working oil port D. Working oil port D is blocked. Working oil port C is connected to the second pressure sensor (16), the oil outlet of the replenishing oil check valve (19), the oil inlet of the second safety valve (20), the first rod chamber (33), and the second rod chamber (35), respectively. The replenishing oil check valve (19) is set close to the first rod chamber (33) and the second rod chamber (35). The second switching valve (18) connects the oil outlet of the cartridge valve (12) to the working oil port C of the second three-position four-way proportional valve (17).

6. A self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism according to claim 5, characterized in that, The cartridge valve (12) is a cone valve structure with an active control cover.

7. A self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism according to claim 5, characterized in that, The constant pressure power unit includes: a first accumulator group (1), a first switching valve (2), a filter (3), a one-way valve (4), a constant pressure valve (5), an electric motor (6), a variable pump (7), a variable piston cylinder (8), an overflow valve (9), a second accumulator group (10), and a third pressure sensor (11). The electric motor (6) drives the variable pump (7), and the constant pressure valve (5) detects the outlet pressure of the variable pump (7) and controls the movement of the valve core. The two working ports at one end of the constant pressure valve (5) are connected to the oil outlet of the variable pump (7) and the oil tank, respectively, and the working port at the other end is connected to the rodless chamber of the variable piston cylinder (8). The rod chamber of the variable piston cylinder (8) is connected to the oil outlet of the variable pump (7). The constant pressure valve (5) and the variable piston cylinder (8) jointly adjust the swashplate angle of the variable pump (7) so that the actuator body (21) is in a constant pressure condition. The oil inlet of the check valve (4) and the relief valve (9) are connected to the oil outlet of the variable pump (7). The outlet of the variable pump (7) is connected to the outlet of the check valve (4) and the filter (3). The outlet of the filter (3) is connected to the first switch valve (2) and one end of the long connecting pipe. The first switch valve (2) is connected to the first accumulator group (1). The other end of the long connecting pipe is connected to the second accumulator group (10) through a hose. The third pressure sensor (11) is set at the inlet of the second accumulator group (10). The second accumulator group (10) is connected to the inlet of the first three-position four-way proportional valve (14) and the second three-position four-way proportional valve (17).

8. A self-redundant multi-stage actuator system for a wind tunnel angle-of-attack mechanism according to claim 7, characterized in that, The first accumulator group (1) and the second accumulator group (10) are airbag accumulators.

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