High-stability controllable testing device and method for low-speed stability performance of hydraulic rotary actuators

Abstract

A high-stability controllable testing device and method for the low-speed stability performance of hydraulic rotary actuators. The testing device comprises a mechanical system, a flow feedback system and a load feedback system, wherein the mechanical system converts a loading force of a hydraulic cylinder (1) into a loading torque, which is transmitted to a component (9) under test by means of a torque sensor (8); the load feedback system comprises the torque sensor (8) and a displacement sensor (3); the torque sensor (8) measures a feedback signal of a load torque applied to the component (9) under test, and feeds the signal back and controls the loading force applied by the hydraulic cylinder; the displacement sensor (3) is configured to measure the displacement of the hydraulic cylinder, and a limit switch is designed to control a stroke of the hydraulic cylinder; and the flow feedback system determines a desired flow rate and an incremental flow rate on the basis of the flow rates at an oil inlet and outlet, coarse adjustment is performed on hydraulic flow provided by the hydraulic cylinder, and then fine adjustment is performed on the hydraulic flow on the basis of the desired flow rate. The two-stage flow regulation of the testing device and method can greatly improve the stability of both the load torque and input flow, thereby ensuring accurate measurement of the stability of high-torque ultra-low-speed hydraulic rotary actuators.

Description

Test apparatus and method for low-speed stability performance of highly stable and controllable hydraulic rotary actuators Technical Field

[0001] This invention belongs to the field of high-performance hydraulic component testing technology, and specifically relates to a device and method for testing the low-speed stability performance of a highly stable and controllable hydraulic rotary actuator. Background Technology

[0002] Hydraulic rotary actuators are components that convert fluid pressure energy into mechanical energy to drive working mechanisms. These include, but are not limited to, internal curve hydraulic motors, gear motors, and vane motors. Compared to electric motors, hydraulic rotary actuators often have a higher power density, and are therefore widely used as core drive components in low-speed, high-torque rotary systems of heavy-duty equipment such as tunnel boring machines, dredgers (bucket wheels) for island-building, sonar towing on ships / research vessels, and aerospace equipment. Their performance directly affects the overall performance of the application system; therefore, comprehensive performance testing of hydraulic components is necessary before installation at the OEM, and during system fault diagnosis and maintenance.

[0003] Stability refers to the speed pulsation of hydraulic components at low speeds, which is of great significance for high-torque hydraulic rotary actuators. On the one hand, under low-speed, 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 lead to output torque pulsation, affecting the position and force control accuracy of the hydraulic rotary actuator. Therefore, measuring low-speed stability is crucial for revealing the inherent characteristics of hydraulic rotary actuators and evaluating their output performance.

[0004] Currently, low-speed stability testing of hydraulic rotary actuators employs three loading methods: mechanical loading, electrical loading, and hydraulic loading. Mechanical loading typically uses a heavy object to generate the loading torque. While the measurement method is stable, the loading torque is difficult to continuously adjust. Under high torque conditions, heavy objects are difficult to install, transport, and precisely adjust, and the complex structure requires sophisticated balance valves and related hydraulic circuits to prevent sudden drops. Therefore, mechanical loading is rarely used. Electrical loading methods include motor loading and magnetic powder braking loading. Electric loading adjusts the loading torque by changing the current, but neither motors nor magnetic powder brakes can achieve stable torque output at ultra-low speeds below 1 r / min. Due to the high power density of hydraulic components, the load torque generated by electric loading is typically smaller than that of hydraulic methods. Therefore, hydraulic loading is the most suitable method for testing high-torque hydraulic rotary actuators. Current hydraulic testing methods utilize the same hydraulic rotary actuator under pump conditions for torsional loading tests. However, the coupling of speed pulsation and torque pulsation of the loading element is difficult to avoid, making it difficult to control the loading torque at low speeds, and the flow pulsation increases continuously as the rotational speed decreases. Besides the testing methods mentioned above, there are currently no suitable testing techniques for testing the ultra-low speed stability of high-torque hydraulic rotary actuators. Summary of the Invention

[0005] This invention addresses the problems existing in current methods for testing the low-speed stability of hydraulic rotary actuators, proposing a highly stable and controllable testing device and method for low-speed stability performance of hydraulic rotary actuators. 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 stable input flow, where the two-stage flow controller design achieves higher stability in load torque and input flow compared to traditional methods. Based on more stable loading torque and input flow, this testing device achieves higher accuracy and low-speed measurement capabilities for measuring low-speed stability. These three design improvements effectively enable accurate measurement of the stability of high-torque, ultra-low-speed hydraulic rotary actuators.

[0006] The objective of this invention is achieved through the following technical solution: a low-speed stability performance testing device for a highly stable and controllable hydraulic rotary actuator, the testing 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 loading torque, which is then transmitted to the measured component via a 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 uses it to control the loading force provided by the hydraulic cylinder; the displacement sensor is used to measure the displacement of the hydraulic cylinder and is designed with limit switches to control the stroke of the hydraulic cylinder.

[0009] The flow feedback system determines the desired flow rate and incremental flow rate based on the inlet and outlet flow rates, performs coarse adjustment on the hydraulic flow rate provided by the hydraulic cylinder, and then fine-tunes the hydraulic flow rate based on the desired flow rate.

[0010] Furthermore, the mechanical system also includes a frame, a winch, a winch rope, and a drum gear coupling; a hydraulic cylinder is mounted on the frame, and the stroke of the hydraulic cylinder is sufficient to rotate the winch and the measured element more than one revolution; the loading force generated by the hydraulic cylinder is converted into loading torque by the winch, and the hydraulic cylinder and the winch are connected by the winch 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] Furthermore, the hydraulic system includes the loading circuit of the hydraulic cylinder, as well as the drive circuit and flushing circuit of the hydraulic component under test;

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

[0013] In the drive circuit, high-pressure oil is input through a fixed-displacement hydraulic pump to drive the tested element, and low-pressure oil flows out to the oil tank; the input hydraulic oil flow rate is adjusted by a proportional servo directional valve, and the oil outlet on the tested element is connected to the oil tank.

[0014] In the flushing circuit, a quantitative hydraulic pump supplies flushing oil to the flushing port of the tested component to ensure the thermal balance of the tested component during long-term operation.

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

[0016] Furthermore, a pressure regulating proportional relief valve is connected in series in 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 displacement of the hydraulic cylinder measured by the displacement sensor. This limit switch sets the test stroke of the hydraulic cylinder. If the hydraulic cylinder reaches its limit stroke, to avoid continuous pressure and damage to the hydraulic cylinder, the required load torque value is set to zero. Otherwise, the output torque is controlled by feedback.

[0018] Furthermore, the flow feedback system adjusts the output flow in two stages. In the first stage, the required incremental flow is measured by the inlet and outlet flow meters. Based on the desired flow and the required incremental flow, the output flow of the fixed displacement hydraulic pump is determined for coarse flow adjustment, providing a flow greater than required. Then, in the second stage, the flow is finely adjusted by the PI controller based on the desired flow, adjusting the flow to the desired value. The control signal for the valve opening of the proportional servo directional valve is dynamically changed based on the signal from the inlet flow meter to maintain the accuracy and stability of the flow.

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

[0020] Furthermore, the limit switch sets the test stroke of the hydraulic cylinder. If the hydraulic cylinder reaches its limit stroke, the required load torque 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 highly stable and 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 the mechanical system and transmitted to the measured component through the torque sensor;

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

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

[0025] (4) Determine the desired flow rate and incremental flow rate based on the inlet and outlet flow rates, and make coarse adjustments to the hydraulic flow rate provided by the hydraulic system;

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

[0027] The beneficial effects of this invention are:

[0028] This invention proposes a highly stable and controllable mechatronic integrated testing device for ultra-low speed stability testing of high-torque hydraulic rotary actuators. The device employs a highly controllable hydraulic winch based on a hydraulic cylinder, which generates a stable and controllable loading torque. Because the structure and friction pairs of the hydraulic cylinder are far less complex than those of the hydraulic rotary actuator, the loading speed of the hydraulic cylinder is extremely stable, greatly avoiding the coupling between the speed pulsation and torque pulsation of the loading element, thus achieving stable control of the loading torque. This testing device proposes using a reverse motor to drive a fixed-displacement hydraulic pump instead of the variable pump in traditional testing devices. The motor speed is controlled by a flow feedback signal, which in turn drives the fixed-displacement hydraulic pump to output flow, reducing flow pulsation from the component's perspective. The device also incorporates a two-stage flow controller, which effectively controls the stability of the input flow to reduce flow pulsation. With more stable load torque and input flow, the measurement accuracy of low-speed stability can reach a higher level. Attached Figure Description

[0029] Figure 1 is a hydraulic schematic diagram of a test device for the low-speed stability performance of a highly stable and controllable hydraulic rotary actuator.

[0030] In the diagram, 1. Hydraulic cylinder; 2. Frame; 3. Displacement sensor; 4. Winding rope; 5. Rotary encoder; 6. Winch; 7. Drum gear coupling; 8. Torque sensor; 9. Component under test; 10. Directional valve; 11. Proportional servo directional valve; 12. Inlet flow meter; 13. Outlet flow meter; 14. Loading motor; 15. Loading fixed displacement hydraulic pump; 16. Loading proportional relief valve; 17. Safety proportional relief valve; 18. Variable frequency motor; 19. Drive fixed displacement hydraulic pump; 20. Pressure regulating proportional relief valve; 21. Drive proportional relief valve; 22. Flushing motor; 23. Flushing fixed displacement hydraulic pump; 24. Relief valve.

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

[0032] Figure 3 is a schematic diagram of a two-stage flow controller. Detailed Implementation

[0033] The invention will now be described in detail with reference to the accompanying drawings and using an internal curve hydraulic motor as a test example:

[0034] As shown in Figure 1, the present invention provides a low-speed stability performance testing device for a highly stable and controllable hydraulic rotary actuator. 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 winch rope 4, and a gear coupling 7. A hydraulic cylinder 1 is mounted on the frame, and its stroke is sufficient to rotate the winch 6 and the measured element 9 more than one revolution. 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 winch rope 4. A torque sensor 8 is connected between the winch 6 and the measured element 9, and the gear coupling 7 is used to compensate for possible angular misalignment. The measured element 9 is an internal 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 drive quantitative hydraulic pump 19, a pressure regulating proportional relief valve 20, a drive 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 for the hydraulic cylinder and drive and flushing circuits for the internal curve hydraulic motor. In the loading circuit, the loading motor 14 is connected to the loading quantitative hydraulic pump 15, which outputs hydraulic oil. The hydraulic pressure is regulated by the loading proportional relief valve 16. The safety proportional relief valve 17 is connected in parallel to the high-pressure oil line, acting as a safety valve. The directional valve 10 is used to switch the extension and retraction of the hydraulic cylinder. In the drive circuit, the variable frequency motor 18 and the drive quantitative hydraulic pump 19 are connected. The drive quantitative hydraulic pump 19 drives the measured element 9 (curved hydraulic motor) through inlet A with high-pressure hydraulic oil input. Low-pressure oil flows out from outlet C and through the drive proportional relief valve 21 to the oil tank. 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 curved hydraulic motor. The oil outlet D on the inner curved hydraulic motor is directly connected to the oil tank through the outlet flow meter 13. In the flushing circuit of the inner curved hydraulic motor, the flushing motor 22 and the flushing quantitative hydraulic pump 23 are connected. 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 curved 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. As shown in Figure 2, the load feedback system includes a torque sensor 8 and a displacement sensor 3; the load torque controller provides the load torque T. a According to the load torque T measured by torque sensor 8 m The feedback signal is used to achieve the required load torque through a PID control algorithm. Specifically, the PID control adjusts the valve opening u of the proportional relief valve. v2 This controls the hydraulic cylinder rod chamber pressure p. h The required load torque is obtained. Furthermore, a limit switch is designed for the hydraulic cylinder based on the displacement measured by displacement sensor 3. This limit switch can set the test stroke x of the hydraulic cylinder. h If the hydraulic cylinder reaches its limit stroke x lim To avoid damaging the hydraulic cylinder with continuous pressure, the required load torque value is set to zero; otherwise, the output torque T... in To the PID control algorithm.

[0038] As shown in Figure 3, the flow feedback system includes a rotary encoder 5, an inlet flow meter 12, and an outlet flow meter 13; in the first stage, the desired flow rate Qa of the flow controller is used to obtain the input flow rate Q through a limit switch. in And incremental flow rate ΔQ and displacement V R To determine the speed n of the variable frequency motor 18 e The calculation formula is: n e =(Q in +ΔQ) / V R This, in turn, drives the fixed-displacement hydraulic pump to output flow, ensuring that the flow provided by the driving hydraulic pump 19 is always greater than the required flow. The limit switch's function is to control the flow once the loading stroke x of the hydraulic cylinder is reached. h Reaching the maximum travel distance x lim To avoid damaging the hydraulic cylinder by continuous pressure, the input flow rate Q is... in Set to zero. Then, in the second stage, based on the signal Q from the inlet flow meter 12. m and input flow Q in Receive the flow deviation signal e Q The flow rate is adjusted to the desired value via a PI controller. The valve opening u of the proportional servo directional valve 11... v1 The control signal is dynamically changed based on the signal from the PI controller to maintain accurate and stable flow. The testing device provided by this invention specifically implements 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 the hydraulic cylinder provides a stable loading torque.

[0040] (2) Achieving flow stability. Establish a proportional servo hydraulic system.

[0041] (2.1) It is proposed to use a reverse motor to drive a fixed-displacement hydraulic pump instead of a variable pump in the traditional test device. The motor speed is controlled by the flow feedback signal, which in turn drives the fixed-displacement hydraulic pump to output flow, thereby reducing flow pulsation from the perspective of components.

[0042] (2.2) Design a two-stage flow controller. By coarsely adjusting the hydraulic flow in the first stage and finely adjusting the hydraulic flow in the second stage, the stability of the input flow can be effectively controlled to reduce flow pulsation.

[0043] (3) Low-speed stability and high-precision testing. The rotary encoder 5 can detect a minimum angle change of approximately 0.0027°. At an ultra-low speed of 0.01 r / min, the rotation angle of the measured component is approximately 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 speeds.

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

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

[0046] (2) Set a limit switch so that if the hydraulic cylinder reaches its limit stroke, the required load torque and the required flow rate are both 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 hydraulic cylinder. a ;

[0048] (4) Determine the desired flow rate Q based on the inlet and outlet flow rates. a The hydraulic flow provided by the hydraulic system is coarsely adjusted based on the required incremental flow rate ΔQ.

[0049] (5) The flow rate is adjusted to the desired value using a PI controller based on the desired flow rate. This is based on the signal Q from the inlet flow meter 12. m Dynamic control of the valve opening u of the proportional servo directional valve v1 To maintain accurate and stable flow.

[0050] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-stability controllable hydraulic rotary actuator low-speed stability performance testing device, characterized in that, The testing 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 loading torque, which is transmitted to the measured element (9) through the torque sensor (8); The load feedback system includes a torque sensor (8) and a displacement sensor (3); the torque sensor (8) measures the load torque feedback signal applied to the measured element (9) and uses it to control the loading force provided by the hydraulic cylinder; the displacement sensor (3) is used to measure the displacement of the hydraulic cylinder and is designed with a limit switch 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 its limit stroke, the required load torque value and the required flow rate are both set to zero; the flow feedback system determines the desired flow rate and incremental flow rate based on the inlet and outlet flow rates, coarsely adjusts the hydraulic flow rate provided by the hydraulic cylinder, and then finely adjusts the hydraulic flow rate based on the desired flow rate; specifically, the flow feedback system adjusts the output flow rate in two stages. In the first stage, the expected flow Qa of the flow controller is inputted through the limit switch to get the input flow Q in , and the incremental flow ΔQ and the displacement V R to determine the rotating speed n of the variable frequency motor (18) e , the calculation formula is: n e =(Q in +ΔQ) / V R ; and then drive the output flow of the constant flow hydraulic pump to ensure that the flow provided by the constant flow hydraulic pump (19) is always greater than the required flow; the limit switch sets the input flow Q in to zero once the loading stroke x h of the loading hydraulic cylinder reaches the limit stroke x lim ; then, in the second stage, the flow deviation signal e Q is obtained based on the signal Q m of the oil inlet flowmeter (12) and the input flow Q in , and the flow is adjusted to the expected value through the PI controller; the control signal of the valve opening degree u v1 of the proportional servo directional valve (11) dynamically changes based on the signal of the PI controller.

2. The high-stable controllable hydraulic rotary actuator low-speed stability performance testing device according to claim 1, characterized in that, The mechanical system also includes a frame (2), a winch (6), a winch rope (4), and a drum gear coupling (7); a hydraulic cylinder (1) is mounted on the frame (2), and the stroke of the hydraulic cylinder (1) is sufficient to make the winch (6) and the measured element (9) rotate more than one revolution; the loading force generated by the hydraulic cylinder (1) is converted into loading torque by the winch (6), and the hydraulic cylinder (1) and the winch (6) are connected by the winch 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 deviations.

3. The high-stable controllable hydraulic rotary actuator low-speed stability performance testing device according to claim 1, characterized in that, The hydraulic system includes the loading circuit of the hydraulic cylinder, as well as the drive circuit and flushing circuit of the hydraulic component under test. The loading circuit outputs hydraulic oil through 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 by a directional valve (10); In the drive circuit, high-pressure oil is input through a fixed-displacement hydraulic pump (19) to drive the measured element (9), and low-pressure oil flows out to the oil tank; the flow rate of the input hydraulic oil is adjusted by a proportional servo directional valve (11), and the oil outlet on the measured element (9) is connected to the oil tank. The flushing circuit provides flushing oil to the flushing port of the tested component (9) through a flushing metering hydraulic pump (23) to ensure the thermal balance of the tested component during long-term operation.

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

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

6. The high-stable controllable hydraulic rotary actuator low-speed stability performance testing device according to claim 1, wherein, The hydraulic cylinder displacement measured by the displacement sensor (3) is used to design a limit switch for the hydraulic cylinder. 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 continuous pressure damage to the hydraulic cylinder. Otherwise, the output torque is used to achieve feedback control.

7. The high-stable controllable hydraulic rotary actuator low-speed stability performance testing device according to claim 1, wherein, The flow feedback system also includes a rotary encoder (5) for measuring the rotation angle information of the component under test.

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

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