Marine hydraulic dynamometer control system based on servo adjusting valve

Abstract

The invention discloses a hydraulic dynamometer control system and method based on a servo adjusting valve, and belongs to the technical field of marine power device testing. The system comprises a dynamometer body, a servo adjusting water inlet valve, a drainage valve, a high-precision weighing device, a rotating speed monitoring device, an intelligent controller and a human-computer interaction interface. A servo motor with micron-order precision is adopted to drive a valve, and a double-closed-loop PID control algorithm and a self-adaptive adjusting technology are combined, so that accurate control over the load characteristics of the hydraulic dynamometer is achieved. The system supports three working modes of constant torque, constant rotating speed and propeller characteristics, and has the characteristics of high response speed, high control precision (torque fluctuation + / -0.15%), high automation degree and the like. The technical problems that a traditional hydraulic dynamometer is low in control precision and slow in response, depends on manual operation and the like are solved, the hydraulic dynamometer is particularly suitable for performance testing of a high-power marine diesel engine and a dual-fuel engine, and the testing efficiency and reliability are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of marine hydraulic dynamometer technology, specifically to a marine hydraulic dynamometer control system based on a servo-controlled valve. The aim is to achieve high-precision control of the load characteristics of the hydraulic dynamometer by dynamically adjusting the valve opening, thereby improving testing accuracy and efficiency. Specifically, it involves the main equipment, including a servo-controlled valve, weighing equipment, speed measuring device, and controller, and can be used for high-power prime mover testing, belonging to the field of powered marine equipment. Background Technology

[0002] With the development of international shipping and ocean-going vessel transportation, marine engines are becoming increasingly powerful, and factory testing for these engines is becoming more stringent. Therefore, the stability and versatility of dynamometers are becoming increasingly important. A hydraulic dynamometer is a device that uses hydraulic resistance to test the load on power machinery (such as engines and motors). Its core principle is to use water flow resistance to simulate actual load. Traditional hydraulic dynamometers typically use fixed or manually adjustable valves to control the water flow, which has the following shortcomings:

[0003] 1. Low control precision: Manual valve adjustment makes it difficult to achieve precise control of minute openings, resulting in large load fluctuations; 2. Slow response speed: Fixed valves cannot match load changes in real time, affecting test stability; 3. Low degree of automation: Reliance on manual operation leads to low efficiency and human error. With the increasing demands for industrial automation and precision testing, there is an urgent need for a control system capable of real-time and precise valve opening adjustment to achieve dynamic optimization of the load characteristics of hydraulic dynamometers. Summary of the Invention

[0004] This invention provides a hydraulic dynamometer control system based on a servo-controlled valve. By driving the valve opening with a servo motor and combining it with a closed-loop feedback control algorithm, the system achieves real-time and high-precision adjustment of water flow resistance, meeting the testing requirements under different load conditions.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A marine hydraulic dynamometer control system based on a servo-controlled valve, characterized by including:

[0007] The dynamometer body is used to absorb the output power of the prime mover through water resistance;

[0008] A servo-controlled water inlet valve is connected to the dynamometer body via a water inlet pipe and is driven by a first servo motor to control the inlet of low-temperature cooling water into the dynamometer body.

[0009] A servo-regulated drain valve is connected to the dynamometer body via a drain pipe and is driven by a second servo motor. It is used to discharge the high-temperature water after absorbing power and maintain the dynamic balance of the system.

[0010] A load monitoring device is installed on the dynamometer body for real-time measurement of torque signals;

[0011] A speed monitoring device is connected to the output shaft of the prime mover and is used to detect the prime mover speed signal in real time.

[0012] The controller is connected to the load monitoring device and the speed monitoring device via signal lines to receive torque and speed measurement signals; it is also connected to the first servo motor and the second servo motor via control lines to output control commands to control the servo-regulated inlet valve and the servo-regulated outlet valve.

[0013] Furthermore, it also includes:

[0014] The human-computer interaction interface is used for parameter setting, real-time data display, and historical data storage.

[0015] Furthermore, the controller controls the valve opening through dual closed-loop feedback, with an error convergence time ≤50ms.

[0016] Furthermore, the controller has a built-in incremental PID algorithm module.

[0017] Furthermore, the controller implements a dual closed-loop control structure, including:

[0018] The inner loop is a flow control loop, which forms a position closed loop through the servo motor encoder feedback of the inlet valve and the outlet valve;

[0019] The outer loop is a torque-speed control loop, which forms a load closed loop through the measurement signals of the load monitoring device and the speed monitoring device;

[0020] Dynamic decoupling between the two rings is achieved through a feedforward compensation algorithm.

[0021] Furthermore, the controller includes an adaptive adjustment module, which is implemented in the following way:

[0022] Establish a three-dimensional database of valve opening degree, flow rate, and torque;

[0023] The system parameters are identified online using the recursive least squares method.

[0024] The proportional, integral, and derivative coefficients of the PID controller are automatically adjusted according to changes in operating conditions.

[0025] Furthermore, three working modes are provided:

[0026] Constant torque mode: The torque value measured by the load monitoring device is used as the main feedback quantity for PID control;

[0027] Constant speed mode: The speed value measured by the speed monitoring device is used as the main feedback quantity for PID control;

[0028] Propeller characteristic mode: Adjusts the matching relationship between torque and speed according to the preset propeller characteristic curve.

[0029] On the other hand, the present invention also provides a hydraulic dynamometer control method based on the above system, characterized in that it includes:

[0030] Step 1: Set the target working mode and parameters through the human-computer interaction interface;

[0031] Step 2: The controller acquires the torque signal from the load monitoring device and the speed signal from the speed monitoring device; Step 3: Selects the control strategy according to the set mode:

[0032] In constant torque mode, the torque deviation is used as the PID control input;

[0033] In constant speed mode, the speed deviation is used as the PID control input;

[0034] In propeller characteristic mode, the target torque and speed are calculated according to the preset curve;

[0035] Step 4: The controller outputs a PWM signal to drive the servo motor and adjust the opening of the inlet and outlet valves;

[0036] Step 5: Optimize control parameters online using an adaptive algorithm;

[0037] Step 6: Monitor the system status in real time and trigger the security protection mechanism.

[0038] Furthermore, the valve adjustment in step 4 employs a cross-control strategy:

[0039] When an increase in load is required, first adjust the opening of the inlet valve, and then coordinate the adjustment of the drain valve.

[0040] When it is necessary to reduce the load, first adjust the opening of the drain valve, and then coordinate the adjustment of the inlet valve.

[0041] During the adjustment process, keep the difference between the inlet and outlet flow rates within a safe range.

[0042] Furthermore, it also includes a dynamic calibration step:

[0043] Periodically close the drain valve completely and record the steady-state torque at different opening degrees of the inlet valve;

[0044] Keep the inlet valve opening constant and record the torque changes of the drain valve at different openings;

[0045] Update the valve characteristic database and correct the control parameters.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] This invention employs dynamic modeling: establishing a mathematical model of valve opening degree in relation to torque and rotational speed, taking into account nonlinear factors such as fluid viscosity and pipeline resistance; closed-loop feedback control of the control algorithm: using the target flow rate / pressure as the setpoint, dynamically adjusting the valve opening through an incremental PID algorithm; and adaptive adjustment in the regulation method: automatically optimizing the corresponding parameters according to load changes to improve system stability.

[0048] The servo regulating valve adopts high-precision servo control: it uses a high-resolution servo motor to achieve micron-level adjustment of valve opening; multi-parameter fusion control: it combines flow and weighing dual closed-loop feedback to eliminate the lag of single-parameter control; intelligent adaptive algorithm: it optimizes PID parameters through machine learning to adapt to load characteristics under different working conditions.

[0049] The valve is driven by a servo motor, achieving micron-level opening adjustment. This overcomes the low precision issues of traditional manual or fixed valve adjustments, significantly reducing load fluctuations. Combined with dual closed-loop feedback for weighing and speed, the lag of single-parameter control is eliminated, ensuring the accuracy of torque and speed measurements. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the marine hydraulic dynamometer control system based on a servo-controlled valve according to the present invention. Detailed Implementation

[0051] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. This embodiment uses the testing of a high-power marine diesel engine as an application scenario, but the scope of protection of the present invention is not limited thereto.

[0052] Please see Figure 1 , Figure 1 This is a schematic diagram of the marine hydraulic dynamometer control system based on a servo-regulated valve of the present invention. As shown in the figure, it includes a servo-regulated inlet valve 1, a servo-regulated outlet valve 2, a dynamometer body device 3, a load monitoring device 4, and a speed monitoring device 5.

[0053] Servo-regulated inlet valve 1 controls the inflow of low-temperature cooling water into the dynamometer body 3. Servo-regulated drain valve 2 discharges the high-temperature water after power absorption and maintains the dynamic balance of the system. The dynamometer body 3 is installed downstream of servo-regulated inlet valve 1 and absorbs the output power of the prime mover through water resistance. In this embodiment, the dynamometer body 3 uses a cast iron shell and has an internal rotor-stator structure, which is formed by the water layer to generate braking torque. During installation, it is necessary to ensure that its axis is strictly aligned with the output shaft of the prime mover.

[0054] The dynamometer body 3 is equipped with a load monitoring device 4 and a speed detection device 5. The load monitoring device 4 is used to calculate and display the power absorbed by the dynamometer body 3 in real time, and the speed detection device 5 is used to calculate and monitor the diesel engine speed in real time.

[0055] In this embodiment, the dynamometer control box includes the following core modules:

[0056] Touchscreen display: Supports data visualization and command input;

[0057] Controller unit: It interacts with the inlet valve servo amplifier and the drain valve servo amplifier through analog / switching signals; it integrates constant torque mode and propeller mode algorithms and adopts an incremental PID control strategy; combined with high-speed counting function, it realizes precise positioning of the servo system.

[0058] Servo actuators: a water inlet valve servo system consisting of a servo amplifier and a servo motor forming a closed-loop control circuit; a drain valve servo system consisting of a servo amplifier and a servo motor forming a closed-loop control circuit.

[0059] This invention achieves rapid response and high-precision adjustment of dynamometer power absorption through dual-valve coordinated control and PID algorithm optimization, making it particularly suitable for performance testing requirements of marine power systems under varying operating conditions. This embodiment is applicable to performance testing of high-power diesel engines, dual-fuel engines, and gas engines.

[0060] This invention combines servo-controlled valves with intelligent control algorithms to achieve high precision, rapid response, and adaptive adjustment of hydraulic dynamometers, significantly improving the accuracy, efficiency, and automation level of load testing, and providing advanced technical support for the research and development and testing of ship power units.

[0061] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent changes and improvements made within the scope of the present invention should be considered as being within the scope of protection claimed by the present invention.

Claims

1. A marine hydraulic dynamometer control system based on a servo-controlled valve, characterized in that, include: The dynamometer body device (3) is used to absorb the output power of the prime mover through water resistance; The servo-controlled water inlet valve (1) is connected to the dynamometer body device (3) through the water inlet pipe and is driven by the first servo motor to control the low temperature cooling water to enter the dynamometer body device (3). The servo-regulated drain valve (2) is connected to the dynamometer body device (3) through a drain pipe and is driven by the second servo motor. It is used to drain the high-temperature water after absorbing power and maintain the dynamic balance of the system. A load monitoring device (4) is installed on the dynamometer body device (3) for real-time measurement of torque signals; Speed ​​monitoring device (5) is connected to the output shaft of the prime mover and is used to detect the prime mover speed signal in real time. The controller is connected to the load monitoring device (4) and the speed monitoring device (5) via signal lines to receive torque and speed measurement signals; it is connected to the first servo motor and the second servo motor via control lines to output control commands to control the servo regulating inlet valve (1) and the servo regulating drain valve (2).

2. The marine hydraulic dynamometer control system based on a servo-controlled valve according to claim 1, characterized in that, Also includes: The human-computer interaction interface is used for parameter setting, real-time data display, and historical data storage.

3. The marine hydraulic dynamometer control system based on a servo-controlled valve according to claim 1, characterized in that, The controller controls the valve opening through dual closed-loop feedback, with an error convergence time of ≤50ms.

4. The marine hydraulic dynamometer control system based on a servo-controlled valve according to claim 3, characterized in that, The controller has a built-in incremental PID algorithm module.

5. The marine hydraulic dynamometer control system based on a servo-controlled valve according to claim 3, characterized in that, The controller implements a dual closed-loop control structure, including: The inner loop is a flow control loop, which forms a position closed loop through the servo motor encoder feedback of the inlet valve and the outlet valve; The outer loop is a torque-speed control loop, which forms a load closed loop through the measurement signals of the load monitoring device (4) and the speed monitoring device (5); Dynamic decoupling between the two rings is achieved through a feedforward compensation algorithm.

6. The marine hydraulic dynamometer control system based on a servo-controlled valve according to claim 3, characterized in that, The controller includes an adaptive adjustment module, which is implemented in the following way: Establish a three-dimensional database of valve opening degree, flow rate, and torque; The system parameters are identified online using the recursive least squares method. The proportional, integral, and derivative coefficients of the PID controller are automatically adjusted according to changes in operating conditions.

7. The marine hydraulic dynamometer control system based on a servo-controlled valve according to any one of claims 1-6, characterized in that, There are three working modes: Constant torque mode: The torque value measured by the load monitoring device (4) is used as the main feedback quantity for PID control; Constant speed mode: The speed value measured by the speed monitoring device (5) is used as the main feedback quantity for PID control; Propeller characteristic mode: Adjusts the matching relationship between torque and speed according to the preset propeller characteristic curve.

8. A hydraulic dynamometer control method based on the system described in any one of claims 1-7, characterized in that, include: Step 1: Set the target working mode and parameters through the human-computer interaction interface; Step 2: The controller acquires the torque signal from the load monitoring device (4) and the speed signal from the speed monitoring device (5); Step 3: Select the control strategy according to the set mode: In constant torque mode, the torque deviation is used as the PID control input; In constant speed mode, the speed deviation is used as the PID control input; In propeller characteristic mode, the target torque and speed are calculated according to the preset curve; Step 4: The controller outputs a PWM signal to drive the servo motor and adjust the opening of the inlet and outlet valves; Step 5: Optimize control parameters online using an adaptive algorithm; Step 6: Monitor the system status in real time and trigger the security protection mechanism.

9. The hydraulic dynamometer control method according to claim 8, characterized in that, The valve adjustment in step 4 employs a cross-control strategy: When an increase in load is required, first adjust the opening of the inlet valve, and then coordinate the adjustment of the drain valve. When it is necessary to reduce the load, first adjust the opening of the drain valve, and then coordinate the adjustment of the inlet valve. During the adjustment process, keep the difference between the inlet and outlet flow rates within a safe range.

10. The hydraulic dynamometer control method according to claim 8, characterized in that, It also includes a dynamic calibration step: Periodically close the drain valve (2) completely and record the steady-state torque of the inlet valve (1) at different opening degrees; Keep the opening of the inlet valve (1) constant and record the torque change of the drain valve (2) at different openings; Update the valve characteristic database and correct the control parameters.

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