Low-speed stability performance testing device and method for high-stability controllable hydraulic rotary actuator

Abstract

The present invention discloses a low-speed stability performance test device and method for a highly stable and controllable hydraulic rotary actuator, the test device comprising a mechanical system, a hydraulic system and an electrical system. The mechanical system comprises a frame, a winch, a winch rope, etc., the hydraulic system comprises a hydraulic cylinder, a measured element, a fixed-displacement radial piston pump, etc., and the electrical system comprises a load feedback system and a flow feedback system. This test device designs a highly controllable hydraulic winch based on a hydraulic cylinder to provide a stable loading torque; a proportional servo hydraulic system is established, in which the design of a two-stage flow controller can greatly improve the stability of the load torque and the input flow. Stable loading torque and input flow can ensure accurate measurement of the stability of a large-torque ultra-low-speed hydraulic rotary actuator.

Description

Technical Field

[0001] The invention belongs to the technical field of high-performance hydraulic component testing, and in particular relates to a low-speed stability performance testing device and method for a high-stability controllable hydraulic rotary actuator. Background Art

[0002] Hydraulic rotary actuators are a type of component that converts liquid pressure energy into mechanical energy to drive a working mechanism, including but not limited to hydraulic components such as inner curve hydraulic motors, gear motors, and vane motors. Compared with electric motors, hydraulic rotary actuators often have greater power density, and are therefore widely used as core drive components for low-speed, high-torque rotary systems such as screw conveyors for shield machines, island-building dredgers, sonar towing for ships / research vessels, and aerospace equipment. Its performance directly affects the working performance of the entire application system, and comprehensive performance testing of hydraulic components is required before installation at the main engine plant, system fault diagnosis, and maintenance.

[0003] Stability refers to the speed pulsation of hydraulic components at low speed, which is of great significance to high-torque hydraulic rotary actuators. On the one hand, under low-speed and high-torque conditions, low-speed stability is determined by nonlinear leakage and friction as well as the structural design of the hydraulic rotary actuator. Therefore, low-speed stability can reflect the inherent characteristics of the hydraulic rotary actuator. On the other hand, low-speed instability can also cause output torque pulsation, affecting the position and force control accuracy of the hydraulic rotary actuator. Therefore, measuring low-speed stability is very important for revealing the inherent characteristics of the hydraulic rotary actuator and evaluating its output performance.

[0004] At present, there are three loading methods for the low-speed stability test of hydraulic rotary actuators: mechanical loading, electrical loading, and hydraulic loading. The mechanical loading method usually uses a heavy object to generate a loading torque. The measurement method is very stable, but its loading torque is difficult to adjust continuously. The heavy object is difficult to install, carry, and accurately adjust under high torque conditions. The structure is complex and requires a complex balance valve and related hydraulic circuits to prevent the sudden drop of the heavy object. Therefore, the mechanical loading method is rarely used. The electrical loading method includes motor loading and magnetic powder brake loading. The electric loading method can adjust the loading torque by changing the current, but neither the motor nor the magnetic powder brake can achieve stable torque output at ultra-low speeds below 1r / min. Due to the high power density of hydraulic components, the load torque generated by the electric loading method is usually smaller than that of the hydraulic method. Therefore, for the test of high-torque hydraulic rotary actuators, the hydraulic loading method is the most suitable. The current hydraulic test method is to use the same hydraulic rotary actuator to perform a torsional loading test under pump conditions, but the coupling of the speed pulsation and torque pulsation of the loading component is difficult to avoid, making the loading torque difficult to control at low speeds and the flow pulsation continues to increase with the decrease in speed. In addition to the above test methods, there is currently no suitable test technology for ultra-low speed stability testing of high-torque hydraulic rotary actuators. Summary of the invention

[0005] In view of the problems existing in the current low-speed stability test methods of hydraulic rotary actuators, the present invention proposes a high-stability and controllable hydraulic rotary actuator low-speed stability performance test device and method. A highly controllable hydraulic winch based on a hydraulic cylinder is designed to generate a stable loading torque. A proportional servo hydraulic system is established to ensure a stable input flow, in which the design of a two-stage flow controller can obtain higher load torque and input flow stability compared with traditional methods. The test device achieves higher accuracy and low-speed measurement capability based on more stable loading torque and input flow, and is used to measure low-speed stability. The above three design improvements can effectively realize the precise stability measurement of large-torque and ultra-low-speed hydraulic rotary actuators.

[0006] The object of the present invention is achieved through the following technical solutions: a low-speed stability performance test device for a highly stable and controllable hydraulic rotary actuator, the test device comprising a mechanical system, a flow feedback system and a load feedback system;

[0007] The mechanical system converts the loading force of the hydraulic cylinder into a loading torque, which is transmitted to the measured element through the torque sensor;

[0008] The load feedback system includes a torque sensor and a displacement sensor; the torque sensor measures the load torque feedback signal applied to the measured element, and feedback controls the loading force provided by the hydraulic cylinder; the displacement sensor is used to measure the displacement of the hydraulic cylinder, and the limit switch is designed to control the stroke of the hydraulic cylinder;

[0009] The flow feedback system determines the expected flow and the incremental flow based on the inlet and outlet flow, roughly adjusts the hydraulic flow provided by the hydraulic cylinder, and then finely adjusts the hydraulic flow based on the expectation.

[0010] Furthermore, the mechanical system also includes a frame, a winch, a rope and a drum gear coupling; the hydraulic cylinder is installed on the frame, and the stroke of the hydraulic cylinder is sufficient to make the winch and the measured element rotate more than one circle; the loading force generated by the hydraulic cylinder is converted into a loading torque through the winch, and the hydraulic cylinder and the winch are connected by a rope; the winch is connected to the measured element through a torque sensor, wherein the drum gear coupling is used to compensate for possible angular deviations.

[0011] Further, the hydraulic system includes a loading circuit of the hydraulic cylinder and a driving circuit and a flushing circuit of the hydraulic element to be tested;

[0012] The loading circuit outputs hydraulic oil through a loading quantitative hydraulic pump, wherein the hydraulic pressure is adjusted by a loading proportional relief valve, and the extension and retraction of the hydraulic cylinder are switched through a directional valve;

[0013] The driving circuit drives the measured element by driving the quantitative hydraulic pump to input high-pressure oil, and the low-pressure oil flows out to the oil tank; the input hydraulic oil flow is adjusted by the proportional servo directional valve, and the oil discharge port on the measured element is connected to the oil tank;

[0014] In the flushing circuit, flushing oil is provided to the flushing port of the measured component through a flushing quantitative hydraulic pump, so as to ensure the thermal balance of the measured component during long-term operation.

[0015] Furthermore, a safety proportional relief valve is connected in parallel to the high-pressure oil circuit of the loading circuit to serve as a safety valve.

[0016] Furthermore, a pressure regulating proportional relief valve is connected in series on the low-pressure oil circuit to adjust the outlet oil pressure of the measured component.

[0017] Furthermore, a limit switch is designed for the hydraulic cylinder based on the hydraulic cylinder displacement measured by the displacement sensor; the limit switch sets the test stroke of the hydraulic cylinder. If the hydraulic cylinder reaches the limit stroke, the required load torque value is set to zero to avoid damage to the hydraulic cylinder due to continuous pressurization, otherwise the output torque is feedback controlled.

[0018] Furthermore, the flow feedback system adjusts the output flow through two stages; in the first stage, the required incremental flow is measured by the oil inlet flowmeter and the oil outlet flowmeter, and the output flow of the driving quantitative hydraulic pump is determined based on the expected flow and the required incremental flow to perform rough flow adjustment to provide a flow greater than the required flow; then, in the second stage, the flow is fine-tuned by the PI controller based on the expected flow to adjust the flow to the expected value; the control signal of the valve opening of the proportional servo directional valve is dynamically changed based on the signal of the oil inlet flowmeter to keep the flow accurate and stable.

[0019] Furthermore, the flow feedback system also includes a rotary encoder for measuring the rotation angle information of the measured element.

[0020] Furthermore, the limit switch sets the test stroke of the hydraulic cylinder. If the hydraulic cylinder reaches the limit stroke, the required load torque value and the required flow rate are both set to zero.

[0021] On the other hand, the present invention also provides a method for testing the low-speed stability performance of a high-stability controllable hydraulic rotary actuator, the method comprising the following steps:

[0022] (1) The loading force of the hydraulic cylinder in the hydraulic system is converted into loading torque through a mechanical system and transmitted to the measured element through a torque sensor;

[0023] (2) A limit switch is set to measure the displacement of the hydraulic cylinder through a displacement sensor. If the hydraulic cylinder reaches the limit stroke, the required load torque value and the required flow rate are set to zero;

[0024] (3) Based on the load torque feedback signal measured by the torque sensor, a PID control algorithm is used to control the load force provided by the hydraulic cylinder;

[0025] (4) Determine the expected flow rate and incremental flow rate based on the inlet and outlet flow rates, and make a rough adjustment on the hydraulic flow rate provided by the hydraulic system;

[0026] (5) Based on the expected flow, the flow is adjusted to the expected value through the PI controller, and the valve opening of the proportional servo directional valve is dynamically controlled based on the signal of the oil inlet flow meter to maintain the accuracy and stability of the flow.

[0027] Beneficial effects of the present invention:

[0028] The present invention proposes a highly stable and highly controllable electromechanical and hydraulic integrated test device for ultra-low speed stability test of large torque hydraulic rotary actuator. This test device designs a highly controllable hydraulic winch based on a hydraulic cylinder, and the loading torque generated by the hydraulic cylinder is stable and controllable. Since the complexity of the structure and friction pair of the hydraulic cylinder is much lower than that of the loading hydraulic rotary actuator, the loading speed of the hydraulic cylinder is very stable, which greatly avoids the coupling of the speed pulsation of the loading element and its torque pulsation, and realizes stable control of the loading torque. This test device proposes to use a reverse motor to drive a quantitative hydraulic pump to replace the variable pump in the traditional test device, control the motor speed through the flow feedback signal, and then drive the quantitative hydraulic pump to output the flow, thereby reducing the flow pulsation from the perspective of the element. This test device designs a two-stage flow controller, which can effectively control the stability of the input flow to reduce the flow pulsation. On the basis of more stable load torque and input flow, the measurement accuracy of low-speed stability can reach a higher level. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is the hydraulic principle diagram of the low-speed stability performance test device for a high-stability controllable hydraulic rotary actuator.

[0030] In the figure, 1. hydraulic cylinder; 2. frame; 3. displacement sensor; 4. rope; 5. rotary encoder; 6. winch; 7. drum gear coupling; 8. torque sensor; 9. measured element; 10. directional valve; 11. proportional servo directional valve; 12. oil inlet flow meter; 13. oil outlet flow meter; 14. loading motor; 15. loading quantitative hydraulic pump; 16. loading proportional relief valve; 17. safety proportional relief valve; 18. frequency conversion motor; 19. driving quantitative hydraulic pump; 20. pressure regulating proportional relief valve; 21. driving proportional relief valve; 22. flushing motor; 23. flushing quantitative hydraulic pump; 24. relief valve.

[0031] Figure 2 Schematic diagram of torque loading control.

[0032] Figure 3 This is the schematic diagram of a two-stage flow controller. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and taking an inner curve hydraulic motor as a tested example:

[0034] like Figure 1 As shown, the present invention provides a low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator, and the testing device includes a mechanical system, a hydraulic system and an electrical system.

[0035] The mechanical system includes a frame 2, a winch 6, a rope 4 and a drum gear coupling 7; a hydraulic cylinder 1 is mounted on the frame, and the stroke of the hydraulic cylinder 1 is sufficient to make the winch 6 and the measured element 9 rotate more than one circle. The loading force generated by the hydraulic cylinder 1 is converted into a loading torque through the winch 6, and the hydraulic cylinder 1 and the winch 6 are connected by the rope 4. The torque sensor 8 is connected between the winch 6 and the measured element 9, wherein the drum gear coupling 7 is used to compensate for possible angular deviations. The measured element 9 is an inner curve hydraulic motor.

[0036] The hydraulic system includes a hydraulic cylinder 1, a measured element 9, a directional valve 10, a proportional servo directional valve 11, a loading motor 14, a loading quantitative hydraulic pump 15, a loading proportional relief valve 16, a safety proportional relief valve 17, a variable frequency motor 18, a driving quantitative hydraulic pump 19, a pressure regulating proportional relief valve 20, a driving proportional relief valve 21, a flushing motor 22, a flushing quantitative hydraulic pump 23 and a relief valve 24; the hydraulic system includes a loading circuit of the hydraulic cylinder and a driving and flushing circuit of the inner curve hydraulic motor. In the loading circuit, the loading motor 14 is connected to the loading quantitative hydraulic pump 15, and hydraulic oil is output through the loading quantitative hydraulic pump 15, wherein the hydraulic pressure is adjusted by the loading proportional relief valve 16, and the safety proportional relief valve 17 is connected in parallel to the high-pressure oil circuit to play the role of a safety valve, and the directional valve 10 is used to switch the extension and retraction of the hydraulic cylinder. The variable frequency motor 18 in the driving circuit is connected to the driving quantitative hydraulic pump 19. The driving quantitative hydraulic pump 19 inputs high-pressure hydraulic oil through the A inlet to drive the measured element 9 (curve hydraulic motor). The low-pressure oil flows out from the C outlet and flows to the oil tank through the driving proportional relief valve 21. The proportional servo directional valve 11 is used to adjust the input flow rate. The pressure regulating proportional relief valve 20 is connected in series in the low-pressure oil circuit to adjust the outlet oil pressure of the inner curve hydraulic motor. The oil discharge port D on the inner curve hydraulic motor is directly connected to the oil tank through the oil outlet flowmeter 13. The flushing motor 22 and the flushing quantitative hydraulic pump 23 are connected in the flushing circuit of the inner curve hydraulic motor. The flushing quantitative hydraulic pump 23 is used to provide flushing oil to the flushing port F, which can ensure the thermal balance of the inner curve hydraulic motor during long-term operation. The relief valve 24 is connected in parallel with the flushing quantitative hydraulic pump 23.

[0037] The electrical system includes a load feedback system and a flow feedback system. Figure 2 As shown, the load feedback system includes a torque sensor 8 and a displacement sensor 3; the loading torque controller provides a loading torque T a , according to the load torque T measured by the torque sensor 8 m Feedback signal, using PID control algorithm to achieve the required load torque, specifically: PID control loading proportional relief valve valve opening u v2 , thereby controlling the hydraulic cylinder rod chamber pressure p h , and obtain the required load torque. In addition, a limit switch is designed for the hydraulic cylinder according to the displacement of the hydraulic cylinder measured by the displacement sensor 3. The limit switch can set the test stroke x of the hydraulic cylinder h , if the hydraulic cylinder reaches the limit stroke x lim To avoid damaging the hydraulic cylinder by constantly pressurizing it, the required load torque value is set to zero. Otherwise, the output torque T in to the PID control algorithm.

[0038] like Figure 3As shown, the flow feedback system includes a rotary encoder 5, an oil inlet flow meter 12 and an oil outlet flow meter 13; in the first stage, the expected flow Qa of the flow controller is obtained through the limit switch to obtain the input flow Q in , and the incremental flow rate ΔQ and displacement V R To determine the speed n of the variable frequency motor 18 e , the calculation formula is: e =(Q in +ΔQ) / V R ; Then drive the quantitative hydraulic pump to output flow, so as to ensure that the flow provided by the driving hydraulic pump 19 is always greater than the required flow. The function of the limit switch is to load the hydraulic cylinder once the loading stroke x h Reach limit travel x lim , to avoid damaging the hydraulic cylinder by constantly pressurizing it, the input flow Q in Then, in the second stage, based on the signal Q of the oil inlet flow meter 12 m and input flow Q in Get the flow deviation signal e Q , the flow rate is adjusted to the desired value through the PI controller. The valve opening u of the proportional servo directional valve 11 v1 The control signal is dynamically changed based on the signal of the PI controller to keep the flow rate accurate and stable. The test device provided by the present invention performs the low-speed stability performance test of the hydraulic rotary actuator as follows:

[0039] (1) Load stability is achieved. The highly controllable hydraulic winch based on hydraulic cylinders provides stable loading torque.

[0040] (2) Flow stability is achieved. A proportional servo hydraulic system is established.

[0041] (2.1) It is proposed to use a reverse motor to drive a quantitative hydraulic pump to replace the variable pump in the traditional test device. The motor speed is controlled by the flow feedback signal, and then the quantitative hydraulic pump is driven to output flow, thereby reducing flow pulsation from the component perspective.

[0042] (2.2) Design a two-stage flow controller that can effectively control the stability of the input flow and reduce flow pulsation by coarse adjustment of the hydraulic flow in the first stage and fine adjustment of the hydraulic flow in the second stage.

[0043] (3) Low-speed stability and high-precision test. The minimum angle change that the rotary encoder 5 can detect is about 0.0027°. At an ultra-low speed of 0.01 r / min, the rotation angle of the measured component is about 0.06° / s, which is more than 22 times the resolution angle of the rotary encoder 5. Therefore, the rotary encoder 5 can accurately measure the speed stability of the measured component at ultra-low speed.

[0044] On the other hand, the present invention also provides a method for testing the low-speed stability performance of a high-stability controllable hydraulic rotary actuator, comprising the following steps:

[0045] (1) The loading force of the hydraulic cylinder in the hydraulic system is converted into a loading torque through a mechanical system and transmitted to the measured element 9 through a torque sensor 8;

[0046] (2) Set a limit switch. If the hydraulic cylinder reaches the limit stroke, the required load torque value and the required flow rate are set to zero.

[0047] (3) Load torque T measured by torque sensor 8 m Feedback signal, using PID control algorithm to control the load torque T provided by the hydraulic cylinder a ;

[0048] (4) Determine the expected flow rate Q based on the inlet and outlet flow rates a and the required incremental flow ΔQ, to roughly adjust the hydraulic flow provided by the hydraulic system;

[0049] (5) Based on the expected flow rate, the flow rate is adjusted to the expected value through the PI controller. Based on the signal Q of the oil inlet flow meter 12 m Dynamically control the valve opening u of the proportional servo directional valve v1 , in order to keep the flow accurate and stable.

[0050] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A low-speed stability performance test device for a high-stability controllable hydraulic rotary actuator, characterized in that: The test device includes a mechanical system, a flow feedback system and a load feedback system; The mechanical system converts the loading force of the hydraulic cylinder into a loading torque, which is transmitted to the measured element (9) via a torque sensor (8); The load feedback system comprises a torque sensor (8) and a displacement sensor (3); the torque sensor (8) measures a load torque feedback signal applied to the measured element (9), and feedback controls the loading force provided by the hydraulic cylinder; the displacement sensor (3) is used to measure the displacement of the hydraulic cylinder, and a limit switch is designed to control the stroke of the hydraulic cylinder; the limit switch sets the test stroke of the hydraulic cylinder, and if the hydraulic cylinder reaches the limit stroke, the required load torque value and the required flow are both set to zero; the flow feedback system determines the expected flow and incremental flow based on the inlet and outlet flow, roughly adjusts the hydraulic flow provided by the hydraulic cylinder, and then finely adjusts the hydraulic flow based on the expectation; specifically: the flow feedback system adjusts the output flow in two stages; In the first stage, the expected flow rate Qa of the flow controller is obtained through the limit switch to obtain the input flow rate Q in , and the incremental flow rate ΔQ and displacement V R To determine the speed n of the variable frequency motor (18) e , the calculation formula is: e =(Q in +ΔQ) / V R ; Then drive the quantitative hydraulic pump to output flow, ensuring that the flow provided by the quantitative driving hydraulic pump (19) is always greater than the required flow; the role of the limit switch is once the loading stroke x of the hydraulic cylinder is loaded h Reach limit travel x lim , the input flow Q in is set to zero; then, in the second stage, based on the signal Q of the oil inlet flow meter (12) m and input flow Q in Get the flow deviation signal e Q , the flow rate is adjusted to the desired value through the PI controller; the valve opening u of the proportional servo directional valve (11) v1 The control signal changes dynamically based on the signal of the PI controller.

2. The low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator according to claim 1 is characterized in that: The mechanical system further comprises a frame (2), a winch (6), a rope (4) and a drum gear coupling (7); the hydraulic cylinder (1) is mounted on the frame (2), the stroke of the hydraulic cylinder (1) being sufficient to cause the winch (6) and the measured element (9) to rotate more than one circle; the loading force generated by the hydraulic cylinder (1) is converted into a loading torque through the winch (6), and the hydraulic cylinder (1) and the winch (6) are connected through the rope (4); the winch (6) is connected to the measured element (9) through a torque sensor (8), wherein the drum gear coupling (7) is used to compensate for possible angular deviation.

3. The low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator according to claim 1 is characterized in that: The hydraulic system includes the loading circuit of the hydraulic cylinder and the driving circuit and flushing circuit of the hydraulic element to be tested; The loading circuit outputs hydraulic oil via a loading quantitative hydraulic pump (15), wherein the hydraulic pressure is regulated by a loading proportional relief valve (16), and the extension and retraction of the hydraulic cylinder (1) are switched via a directional valve (10); The driving circuit drives the measured element (9) by inputting high-pressure oil through a driving quantitative hydraulic pump (19), and the low-pressure oil flows out to the oil tank; the flow rate of the input hydraulic oil is adjusted through a proportional servo directional valve (11), and the oil discharge port on the measured element (9) is connected to the oil tank; In the flushing circuit, flushing oil is supplied to the flushing port of the measured element (9) through a flushing quantitative hydraulic pump (23), thereby ensuring the thermal balance of the measured element during long-term operation.

4. The low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator according to claim 3 is characterized in that: A safety proportional relief valve (17) is connected in parallel to the high-pressure oil line of the loading circuit to serve as a safety valve.

5. The low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator according to claim 3 is characterized in that: A pressure regulating proportional relief valve (20) is connected in series on the low-pressure oil circuit to adjust the outlet oil pressure of the measured element (9).

6. The low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator according to claim 1 is characterized in that: A limit switch is designed for the hydraulic cylinder according to the displacement of the hydraulic cylinder measured by the displacement sensor (3); the limit switch sets the test stroke of the hydraulic cylinder. If the hydraulic cylinder reaches the limit stroke, the required load torque value is set to zero to avoid damage to the hydraulic cylinder due to continuous pressurization. Otherwise, the output torque is feedback controlled.

7. The low-speed stability performance testing device for a high-stability controllable hydraulic rotary actuator according to claim 1 is characterized in that: The flow feedback system also includes a rotary encoder (5) for measuring the rotation angle information of the measured element.

8. A testing method for the low-speed stability performance testing device of a high-stability controllable hydraulic rotary actuator according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: (1) The loading force of the hydraulic cylinder in the hydraulic system is converted into a loading torque through a mechanical system and transmitted to the measured element (9) through a torque sensor (8); (2) Setting a limit switch and measuring the displacement of the hydraulic cylinder through the displacement sensor (3). If the hydraulic cylinder reaches the limit stroke, the required load torque value and the required flow rate are set to zero; (3) Based on the load torque feedback signal measured by the torque sensor (8), a PID control algorithm is used to control the load force provided by the hydraulic cylinder; (4) Determine the expected flow rate and incremental flow rate based on the inlet and outlet flow rates, and make a rough adjustment on the hydraulic flow rate provided by the hydraulic system; (5) Based on the expected flow, the flow is adjusted to the expected value through the PI controller, and the valve opening of the proportional servo directional valve is dynamically controlled based on the signal of the oil inlet flow meter to maintain the accuracy and stability of the flow.

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