Synchronous drive friction type novel electro-hydraulic load simulator

Abstract

The application relates to a synchronous driving friction type novel electro-hydraulic load simulator, which comprises a controller, an oil tank, an oil suction filter, an alternating current servo motor, a hydraulic pump, a pressure gauge, an energy accumulator, an overflow valve, an electromagnetic reversing valve, a hydraulic oil cylinder, a feedback sensor, an oil level gauge, a spring, a friction plate and a universal bullseye ball; the feedback sensor is connected with the controller; the controller compares with input instructions, outputs a control signal to control the electromagnetic reversing valve, the servo control system has high reliability and high stability; the spring is used for realizing the opening of the friction plate, and the friction force generated by the locking of the friction plate is realized by the precise synchronous movement of two valve control cylinder electro-hydraulic servo systems; the loading hydraulic cylinder piston rod and the rudder hydraulic cylinder piston rod are connected through the friction plate, the position interference of the rudder cylinder piston rod to the loading cylinder piston rod and the forced flow generated by the force can be overcome, so that the redundant force is inhibited, and the loading precision of the loading cylinder is ensured.

Description

Technical Field

[0001] This patent relates to the fields of hydraulic transmission systems and electro-hydraulic servo control systems, specifically to a novel synchronous drive friction-type electro-hydraulic load simulator. Background Technology

[0002] In the engineering field, most man-made equipment operates in unknown natural environments. Faced with diverse loads in these environments, to ensure safety and minimize unnecessary losses, it is necessary to test man-made equipment and systems in advance, verify the effectiveness of control algorithms, ensure the equipment meets required performance, and improve and optimize the equipment. Especially in high-tech fields such as aerospace and weaponry, the performance requirements for equipment—precision, speed, reliability, and lifespan—are increasingly stringent. In many cases, failure to meet these requirements can have irreparable or even unbearable consequences. Therefore, testing new equipment under appropriate load conditions is essential. Load simulators, as experimental devices capable of simulating load signals in laboratory environments, can simulate inertial forces, elastic forces, aerodynamics, vehicle drag and braking forces, and ocean wave dynamics. They are widely used in aerospace, defense, shipbuilding, automotive, and robotics industries, and their importance is self-evident. Summary of the Invention

[0003] The purpose of this invention is to provide a load simulator that can simulate the resistance load generated by air and water on a servo motor. It is widely used in servo motor load, resistance and pressure testing. Redundant force interference is the main factor affecting the loading performance of the load simulator. How to eliminate redundant force interference to the greatest extent is the key issue to improve the loading performance of the load simulator. In view of the shortcomings of the existing technology, a new type of synchronous drive friction electro-hydraulic load simulator is provided.

[0004] To address the above problems, the present invention provides the following technical solution.

[0005] This invention patent connects the piston rod of the loading hydraulic cylinder and the piston rod of the servo hydraulic cylinder through friction plates. Compared with the original rigid fixed connection between the two, this allows the servo piston rod to have appropriate axial movement without affecting the normal loading of the servo cylinder by the loading cylinder. This can overcome the positional interference of the servo cylinder piston rod on the loading cylinder piston rod and the resulting forced flow, thereby suppressing excess force and ensuring the loading accuracy of the loading cylinder.

[0006] The opening of the friction plates is achieved by springs, while the locking of the friction plates to generate friction is achieved by the electro-hydraulic servo system of two radially valve-controlled cylinders. The precise synchronous movement of these two hydraulic cylinders can avoid unnecessary radial movement of the piston rods of the loading cylinder and the servo cylinder, and can also generate the required friction by pushing the friction plates and the piston rods of the loading cylinder and the servo cylinder into contact. The magnitude of the friction is related to the coefficient of friction, which can be achieved by selecting appropriate friction plate materials, and also to the output of the two radial hydraulic cylinders. That is, the greater the output of the two radial hydraulic cylinders, the greater the friction, and vice versa. This can be easily achieved by autonomously controlling the two radial hydraulic cylinders.

[0007] The radial two-valve-controlled electro-hydraulic servo system functions as both an electro-hydraulic position servo system and an electro-hydraulic force servo system. Before the friction plate contacts the piston rod, it operates as a position servo system, relying on a displacement sensor to detect and provide feedback for closed-loop control of the piston rod's displacement. Once the friction plate contacts the piston rod and friction is generated, it becomes a force servo system, relying on a force sensor to detect and provide feedback for closed-loop control of the piston rod's output force. The key "trigger point" for switching between the position and force servo systems is the point where the force sensor's output value is non-zero. Synchronization and position / force switching between the radial two-valve-controlled electro-hydraulic servo systems are achieved using a synchronization controller.

[0008] The universal bullseye can achieve radial force on the friction plate, and avoid the sliding friction resistance between the ends of the piston rods of the two radially controlled cylinders and the outer surface of the friction plate, thus realizing rolling motion. It can also realize smooth axial movement along the piston rod of the loading cylinder when the friction plate and the piston rod of the loading cylinder are rigidly connected.

[0009] Beneficial Effects: In the original valve-controlled cylinder type electro-hydraulic load simulator, the piston rod of the loading cylinder and the piston rod of the servo cylinder are rigidly fixed. During loading, the servo cylinder piston rod exerts a strong positional disturbance on the loading cylinder piston rod, generating forced flow in the loading cylinder and resulting in excess force. This excess force severely affects the loading accuracy of the loading cylinder. The new synchronous drive friction type electro-hydraulic load simulator uses friction plates to connect the two piston rods. This new friction structure can transmit the axial loading force of the loading cylinder on the servo cylinder while allowing for a certain axial displacement of the servo cylinder piston rod relative to the loading cylinder piston rod. This effectively overcomes the strong positional disturbance and forced flow, thereby suppressing excess force and ensuring the loading accuracy of the loading cylinder. Attached Figure Description

[0010] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0011] Appendix Figure 1 This is a schematic diagram of the structure of a novel friction-type electro-hydraulic load simulator system;

[0012] Appendix Figure 2 A system block diagram for loading the control system module;

[0013] Appendix Figure 3 This is a system block diagram of the servo control system module under test.

[0014] Appendix Figure 4 This is a system block diagram of the friction plate synchronous control system module;

[0015] Appendix Figure 5 This is a magnified two-dimensional view of a portion of the friction plate;

[0016] Appendix Figure 6 This is a partial 3D view of the friction plate; Detailed Implementation

[0017] The following is combined Figures 1 to 4 This embodiment describes a synchronous drive friction-type novel electro-hydraulic load simulator, which includes an oil tank (1), an oil level gauge (2), an oil suction filter (3), an overflow valve (4), a hydraulic pump (5), an AC servo motor (6), a pressure gauge (7), an energy storage device (8), a hydraulic cylinder, an electromagnetic reversing valve (10), a controller (12, 13), a feedback sensor, a spring (17), a friction plate (18), and a universal bullseye (20).

[0018] The displacement sensor (16) and the electro-hydraulic servo valve are installed on the servo cylinder (14) under test; the signal output terminal of the displacement sensor (16) is connected to the input terminal of the controller (15), the output terminal of the controller (15) is connected to the input terminal of the servo amplifier, and the given displacement command output terminal of the servo amplifier is connected to the command input terminal of the electro-hydraulic servo valve; the displacement of the servo is controlled by the controller through the given servo control signal.

[0019] The piston rods of the two radial hydraulic cylinders (9) have universal bullseyes (20) at their front ends, which can realize the radial force on the friction plate and avoid the sliding friction resistance between the piston rod ends of the two radial valve-controlled cylinders (9) and the outer surface of the friction plate (18), thereby realizing rolling motion. It can also realize the smooth axial movement of the piston rod of the loading cylinder (11) when the friction plate (18) and the piston rod of the loading cylinder (11) are rigidly connected. The displacement of the hydraulic cylinder piston and the thrust generated by the hydraulic cylinder can be measured in real time by the displacement sensor (16) and the force sensor (19), respectively. The hydraulic cylinder displacement and the hydraulic rod thrust together feed the signal back to the synchronous controller (13). The two radial hydraulic cylinders (9) apply radial pressure to the friction plate (18) simultaneously under the drive of the electro-hydraulic servo valve, thereby ensuring that the applied pressure can be evenly distributed on the contact surface of the friction plate (18), making the force loading more stable and easier to servo control. In this way, the synchronous drive friction loading electro-hydraulic load simulator can be used as a dynamic performance testing machine for friction materials.

[0020] The friction plate (18) is fixed at the front end of the piston rod of the loading cylinder. There is a fixed spring (17) in the middle of the friction plate, which can make the friction plates have a certain distance. Under the movement of the two radial hydraulic cylinders (9), the friction plate (18) clamps the piston rod of the servo cylinder (14), so that the force of the loading cylinder (11) acts on the servo under test. There is a force sensor (19) at the front end of the loading cylinder (11). The signal output end of the force sensor (19) is connected to the first input end of the controller (12). The loading control signal is connected to the second input end of the controller. The controller (12) compares the signal and controls the solenoid valve to switch (10), thereby controlling the force on the piston rod of the loading cylinder (11).

[0021] As can be seen from the above, since there is friction between the upper and lower friction plates (18) and the piston rod of the tested servo cylinder (14), the pressure F applied by the upper and lower friction plates according to the radial hydraulic cylinder control signal is converted into a corresponding force applied to the tested servo cylinder (14) through the friction and relative movement between the friction plates (18). Since the friction plates (18) are welded to the front end of the loading cylinder piston rod through the upper and lower friction plates, the upper and lower friction plates will always maintain a certain direction of movement. In this way, the main movement of the tested servo cylinder (14) will not interfere with the hydraulic cylinder applying pressure to the friction plates (18), and the movement of the tested servo cylinder (14) will not interfere with the generated force. That is, there is no extra force generated by the main movement of the tested servo cylinder (14) in this load simulator. The force generated by the loading cylinder (11) will be transmitted to the tested servo cylinder (14) through the extension of the radial hydraulic cylinders (9) as described above, which squeezes the friction plates (18), thereby realizing the external force loading on the servo. The generated force is measured by the force sensor (19) and transmitted to the controller (12). The controller calculates the control signal based on the given desired force signal and the feedback force signal, and transmits the calculated control signal to the servo valve (10) through the servo amplifier to drive the two radial hydraulic cylinders (9) to apply pressure to the friction plate (18). In turn, force is generated under the movement of the piston rod of the loading cylinder and the friction plate (18), thus forming a force loading closed-loop system. Its control block diagram is attached. Figure 2 As shown. The servo system under test is generally also a closed-loop servo control. The displacement of the simulated servo system is measured by the displacement sensor (16) and fed back to the controller (15). Using the given desired displacement signal and the feedback displacement signal, the controller calculates the control signal according to the design and transmits it to the large servo valve (10) through the servo amplifier to drive the cylinder (14) of the servo under test to move. In this way, the displacement closed-loop control of the simulated servo system is formed. Its control block diagram is shown in the attached figure. Figure 3 As shown.

[0022] The synchronous drive friction loading electro-hydraulic load simulator described in this embodiment is a system used to accurately simulate the actual force loading of a load-bearing object. Through innovative structural design, this system completely eliminates the serious interference of redundant forces generated by the main motion of the loaded object during loading in traditional electro-hydraulic load simulators. It achieves high-precision, high-frequency response, and high-dynamic force loading of the loaded object under any main motion of the loaded object, reduces the complexity of the load simulator's loading control algorithm, and completely solves the series of destructive loading performance effects of redundant forces on the load simulator. The synchronous drive friction loading new type electro-hydraulic load simulator uses friction plates (18) to connect the two piston rods. Through the designed new friction structure, it can transmit the axial loading force of the loading cylinder (11) on the servo cylinder (14) and allow the servo cylinder piston rod to have a certain axial displacement relative to the loading cylinder piston rod. In this way, it can effectively overcome the strong position interference and forced flow, thereby suppressing redundant forces and ensuring the loading accuracy of the loading cylinder. This synchronous drive electro-hydraulic load simulator has advantages such as no redundant force, high loading accuracy, high system bandwidth, simple and reliable control algorithm, and excellent small-amplitude loading performance. By simulating the force load spectrum of the servo system of missiles, aircraft, etc., it can provide economical, high-precision and high-reliability equipment support for improving the performance of the loaded servo system.

Claims

1. A synchronous drive frictional electro-hydraulic load simulator, characterized by: Includes an oil tank (1), an oil level gauge (2), an oil suction filter (3), an overflow valve (4), a hydraulic pump (5), an AC servo motor (6), a pressure gauge (7), an accumulator (8), a hydraulic cylinder, an electromagnetic directional valve (10), a first controller (12), a second controller (13), a feedback sensor, a spring (17), a friction plate (18), and a universal bullseye (20); The oil tank is equipped with an oil level gauge (2), and the oil suction filter (3) is connected to the hydraulic pump (5). The oil level gauge (2) is used to measure the position of the hydraulic oil in the oil tank (1), and the oil suction filter (3) filters impurities in the hydraulic oil to protect the hydraulic system. The hydraulic pump (5) is connected to the AC servo motor (6), pressure gauge (7), accumulator (8), solenoid directional valve (10) and relief valve (4) respectively. The relief valve (4) protects the hydraulic circuit. The AC servo motor (6) drives the rotation of the hydraulic pump (5). The pressure gauge (7) measures the hydraulic oil pressure in the oil circuit. The accumulator (8) stores the hydraulic oil energy. When the hydraulic pump (5) suddenly fails during operation, it provides energy to the hydraulic system. The electromagnetic reversing valve (10) is connected to the hydraulic cylinder. By reversing the electromagnetic reversing valve (10), the hydraulic cylinder is driven to extend and retract under the drive of the hydraulic pump (5). The feedback sensor is connected to the hydraulic cylinder and the controller respectively. The hydraulic cylinder motion signal is collected by the feedback sensor and input to the controller. The controller outputs a signal to control the operation of the electromagnetic directional valve (10). A drive adapter, located between the servo motor (6) and the controller, is used to convert, under the control of one or more control signals, including position control signals, pressure control signals, and flow control signals output by the controller, into signals that match the corresponding motion of the servo motor (6). The spring (17) is connected to the friction plate (18), and the spring is fixed between the two friction plates (18) by two cylinders. The spring (17) creates a gap between the two friction plates (18). The friction plate (18) is fixed together with the piston rod of the loading cylinder (11) by welding. The contact point between the inner surface of the friction plate (18) and the piston rod of the servo cylinder (14) is arc-shaped, which changes the line contact to a surface contact and provides greater friction. The universal bullseye (20) is connected to the top of the piston rod of the radial synchronous hydraulic cylinder (9) to avoid sliding friction resistance between the end of the piston rod of the radial synchronous hydraulic cylinder (9) and the outer surface of the friction plate (18), thereby realizing rolling motion.

2. The synchronous drive friction-type electro-hydraulic load simulator according to claim 1, characterized in that: The hydraulic cylinders include a loading cylinder (11), a steering cylinder (14), and a radial synchronization hydraulic cylinder (9); the feedback sensors include a force sensor (19) and a position sensor (16); The piston rod of the loading cylinder is equipped with a force sensor (19) at its front end. The force sensor (19) converts the force it receives into an electrical signal through the deformation of the piston rod and inputs it into the first controller (12). The piston rod of the servo cylinder is equipped with a position sensor (16) at the front end. The position sensor (16) measures the displacement of the piston rod and converts the position signal into an electrical signal, which is then input to the third controller (15). The piston rod of the radial synchronous hydraulic cylinder is equipped with a force sensor (19) and a position sensor (16) at its front end. The force and position of the piston rod are measured, and the force and position signals are converted into electrical signals and input to the second controller (13).

3. The synchronous drive friction-type electro-hydraulic load simulator according to any one of claims 1-2, characterized in that: The loading cylinder (11) and the test servo cylinder (14) are connected together by a friction plate (18). Under the movement of the radial synchronous hydraulic cylinder (9), the friction plate (18) clamps and releases the piston rod of the test servo cylinder (14). The opening of the friction plate (18) is achieved by the spring (17), while the locking of the friction plate (18) generates friction by the two radial valve-controlled cylinder electro-hydraulic servo systems. The precise synchronous movement of these two hydraulic cylinders avoids unnecessary radial movement of the piston rods of the loading cylinder (11) and the servo cylinder (14). The required friction is generated by pushing the piston rods of the friction plate (18) and the loading cylinder (11) to contact with the piston rods of the servo cylinder (14). The magnitude of the friction is related to the coefficient of friction, which is achieved by selecting the friction plate material, and also to the output of the two radial synchronous hydraulic cylinders (9). That is, the greater the output of the two radial synchronous hydraulic cylinders (9), the greater the friction, and vice versa. The radial synchronous hydraulic cylinder electro-hydraulic servo system is both an electro-hydraulic position servo system and an electro-hydraulic force servo system. Before the friction plate (18) contacts the piston rod of the tested servo cylinder, it is a position servo system. At this time, the position sensor (16) detects and feeds back the displacement of the piston rod of the loaded cylinder in a closed loop control. After the friction plate contacts the piston rod of the tested servo cylinder and when friction is generated, it is a force control servo system. At this time, the force sensor (19) detects and feeds back the output force of the piston rod in a closed loop control.

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