Real-time working condition load simulation system of hydraulic excavator power system

Abstract

The invention discloses a real-time working condition load simulation system of a hydraulic excavator power system, and relates to the technical field of hydraulic excavators. The system comprises an excavator power system, a load loading hydraulic system, a whole vehicle control unit and a joint simulation system. The excavator power system comprises an oil tank, a main pump, a pilot pump, a pilot hydraulic control handle, a signal control valve and a multi-way valve. The load loading hydraulic system comprises a one-way valve liquid bridge and a proportional overflow valve. The one-way valve liquid bridge comprises a first one-way valve, a second one-way valve, a third one-way valve and a fourth one-way valve, the third one-way valve outlet is connected to the first one-way valve inlet. The fourth one-way valve outlet is connected to the second one-way valve inlet. A port A of the multi-way valve is connected between the first one-way valve and the third one-way valve. A port B of the multi-way valve is connected between the second one-way valve and the fourth one-way valve. An inlet of the proportional overflow valve is connected to an outlet of the first one-way valve. An outlet of the proportional overflow valve is connected to an inlet of the third one-way valve.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic excavators, and in particular to a real-time working condition load simulation system of a hydraulic excavator power system. Background Art

[0002] A variety of technological approaches, including hybrid powertrains, pure electric drives, and distributed electro-hydraulic systems, are being applied to various types of machinery. Evaluating the performance of these innovative systems is crucial for reducing R&D costs and time by avoiding expensive field testing. However, traditional evaluation methods rely on load testing in a field environment, consuming significant human and material resources and making it difficult to quickly and efficiently evaluate the comprehensive performance of powertrains before the entire machine leaves the factory. Therefore, simplifying load testing methods and replacing field testing with load simulations is a pressing need to improve R&D efficiency and reduce costs.

[0003] A common load simulation method in existing technology uses a proportional relief valve instead of an actuator cylinder. A preset load spectrum is converted into a control signal, which is applied to the proportional relief valve to achieve simple pressure loading at the outlet of the multi-way valve. This approach reduces the size of the test system and avoids complex field operations, but it relies on pre-collecting load data under fixed working conditions. Specifically, it statically applies the load spectrum to pressure valve control, simulating the magnitude of the load pressure, but ignores the dynamic interaction between flow and pressure in actual operation of construction machinery.

[0004] This existing method has significant drawbacks, as it fails to address the dynamic flow-pressure coupling characteristics of the excavator during full operation. In actual operation, the system output flow and load pressure exhibit a complex coupling relationship, resulting in drastic pressure variations at different flow rates. Static loading, on the other hand, only simulates the magnitude of pressure and cannot replicate this dynamic behavior. Consequently, the test results from load simulation are disconnected from the actual operation of the entire machine, reducing the accuracy and reliability of performance evaluation and failing to provide a reliable testing basis for engineering machinery power systems. Summary of the Invention

[0005] The present invention provides a real-time working load simulation system for a hydraulic excavator power system to improve at least one of the above technical problems.

[0006] In order to solve the above technical problems, the present invention provides a real-time working condition load simulation system of a hydraulic excavator power system, which includes an excavator power system, a load loading hydraulic system, a vehicle control unit communicatively connected to the load loading hydraulic system, and a joint simulation system communicatively connected to the vehicle control unit.

[0007] The excavator power system includes an oil tank, a main pump and a pilot pump connected to the oil tank, a pilot hydraulic control handle connected to the pilot pump, a signal control valve connected to the pilot hydraulic control handle, and a multi-way valve connected to the main pump and the signal control valve.

[0008] The load-applying hydraulic system includes a one-way valve bridge coupled to the multi-way valve and a proportional relief valve coupled to the one-way valve bridge. The one-way valve bridge includes a first one-way valve and a second one-way valve with connected outlets, and a third one-way valve and a fourth one-way valve with connected inlets. The outlet of the third one-way valve is connected to the inlet of the first one-way valve. The outlet of the fourth one-way valve is connected to the inlet of the second one-way valve.

[0009] The A port of the multi-way valve is connected between the first one-way valve and the third one-way valve. The B port of the multi-way valve is connected between the second one-way valve and the fourth one-way valve.

[0010] The inlet of the proportional relief valve is connected to the outlet of the first one-way valve. The outlet of the proportional relief valve is connected to the inlet of the third one-way valve.

[0011] As a further optimization, the load-applying hydraulic system further includes a first flow sensor and a first pressure sensor connected to port A, and a second flow sensor and a second pressure sensor connected to port B.

[0012] The vehicle control unit is communicatively connected to the first flow sensor, the second flow sensor, the first pressure sensor, the second pressure sensor, the first one-way valve, the second one-way valve, the third one-way valve, the fourth one-way valve, and the proportional relief valve.

[0013] As a further optimization, the joint simulation system includes a vehicle software control platform and a dynamics simulation calculation software platform. The dynamics simulation calculation software platform includes an excavator hydraulic system simulation module, an excavator kinematic system simulation module, and a soil resistance simulation module.

[0014] The vehicle software control platform is used to analyze the analog electrical signals of the first one-way valve, the second one-way valve, the third one-way valve, and the fourth one-way valve from the vehicle control unit, and send the analyzed signal results to the dynamic simulation calculation software platform.

[0015] The dynamics simulation software platform is used to simulate the actual operation of an excavator. The excavator hydraulic system simulation module simulates the excavator's hydraulic drive system. The excavator kinematic system simulation module simulates the excavator's mechanical structure and motion. The soil resistance simulation module simulates real soil to simulate the application of soil loads. The module also transmits the pressure of the cylinder drive chamber in the excavator hydraulic system simulation module to the vehicle software control platform in real time.

[0016] The dynamics simulation software platform sends the simulation results to the vehicle software control platform. The vehicle software control platform converts the simulation results into control parameters and sends them to the vehicle control unit. The vehicle control unit then controls the load-loading hydraulic system, achieving information exchange and control between the simulation and hardware.

[0017] As a further optimization, the vehicle software control platform converts the load pressure signal into the control parameters of the proportional relief valve and sends it to the vehicle control unit.

[0018] The vehicle control unit is used to receive analog electrical signals from the first flow sensor, the second flow sensor, the first pressure sensor and the second pressure sensor in the load loading hydraulic system, and send them to the vehicle software control platform. At the same time, it receives control parameters of the vehicle software control platform and sends control signals to the proportional relief valve to adjust the valve core opening of the proportional relief valve, thereby controlling the inlet pressure of the proportional relief valve to achieve load end loading.

[0019] As a further optimization, the vehicle control unit and the vehicle software control platform are connected via CAN bus communication using Peak-CAN.

[0020] The whole vehicle software control platform and the dynamics simulation calculation software platform are communicatively connected via a joint simulation interface.

[0021] The vehicle control unit uses a proportional-integral-differential algorithm for closed-loop control of the proportional relief valve, calculating the error between the current cylinder pressure (solved in the simulation) and the proportional relief valve inlet pressure. The proportional component adjusts based on the current error, the integral component eliminates the system's steady-state error, and the differential component predicts and corrects the error's changing trend. This allows for real-time adjustments to the proportional relief valve's control current, further adjusting the valve spool opening to align the inlet pressure with the target loading pressure.

[0022] As a further optimization, the multi-way valve is provided with a control port, an oil inlet, an oil discharge port, port A, and port B. The multi-way valve is configured such that the control port can control the oil inlet to switch between connecting to one of port A and port B. The port A or port B that is not connected to the oil inlet is switched to connect to the oil discharge port. The control port is connected to the signal control valve. The oil inlet is connected to the main pump. The oil discharge port is connected to the fuel tank.

[0023] As a further optimization, when the excavator's bucket is in the retracted working condition, oil flows out from port A of the multi-way valve and oil returns from port B. The loading pressure of the proportional relief valve is the driving pressure of the excavator's rodless chamber.

[0024] At this point, the excavator's power system is operating. The drive motor drives the main pump and pilot pump to draw oil from the tank and deliver it to the multi-way valve and pilot hydraulic control handle, respectively. The drive oil circuit outputs oil from port A of the multi-way valve, then passes through the first flow sensor and the first check valve in the check valve bridge to the proportional relief valve. The oil then flows through the proportional relief valve, the fourth check valve, and the second flow sensor to port B of the multi-way valve, returning to the tank.

[0025] When the system is running, the vehicle control unit collects the current signals fed back by the first pressure sensor and the first flow sensor in real time, and uses Peak-CAN to send them to the vehicle software control platform through the CAN bus.

[0026] The vehicle software control platform converts the received CAN messages into the current cylinder drive flow and sends them to the excavator hydraulic system simulation module in the dynamic simulation calculation software platform through the joint simulation interface.

[0027] The excavator hydraulic system simulation module transmits the hydraulic parameters of the system when it is working to the excavator kinematic system simulation module to control the excavator mechanical model to perform simulated movement.

[0028] The soil resistance simulation module simulates the real soil resistance and acts on the excavator kinematic system simulation module to simulate the application of soil resistance load and obtain the bucket cylinder pressure of the excavator hydraulic system simulation module at this time.

[0029] The dynamics simulation software platform transmits the simulated bucket cylinder pressure results to the vehicle software control platform via a co-simulation interface. The vehicle software control platform converts the cylinder pressure parameters obtained from the dynamics simulation software platform into control current parameters for the proportional relief valve. Using Peak-CAN, the cylinder pressure and proportional relief valve control current parameters are transmitted to the vehicle control unit via the CAN bus.

[0030] The vehicle control unit uses the cylinder pressure received from the vehicle software control platform as the target pressure and uses the first pressure sensor as feedback pressure to perform a proportional-integral-differential algorithm. This algorithm calculates the error between the current cylinder pressure, as determined in the co-simulation system, and the proportional relief valve inlet pressure. The proportional component adjusts based on the current error, the integral component eliminates the system's steady-state error, and the differential component predicts and corrects the error's changing trend, enabling real-time adjustments to the proportional relief valve's control current. The current sent by the vehicle control unit's PWM generator port is then adjusted to control the proportional relief valve's spool opening, adjusting its inlet pressure and ultimately loading the excavator's power system.

[0031] As a further optimization, when the bucket of the excavator is in the outward-turning working condition, oil is discharged from port B of the multi-way valve and oil is returned from port A. The loading pressure of the proportional relief valve is the driving pressure of the excavator's rod chamber.

[0032] At this time, the excavator power system is running, and the drive motor drives the main pump and the pilot pump to suck oil from the oil tank and output the oil to the multi-way valve and the pilot hydraulic control handle respectively, driving the oil circuit to output from the B port of the multi-way valve, and then passes through the second flow sensor and the second one-way valve in the one-way valve liquid bridge to the proportional relief valve, and then the oil passing through the proportional relief valve flows through the third one-way valve and the first flow sensor to the A port of the multi-way valve to return the oil to the oil tank.

[0033] When the system is running, the vehicle control unit collects the second pressure sensor, the second flow sensor, and the feedback current signal in real time, and uses Peak-CAN to send it to the vehicle software control platform through the CAN bus.

[0034] The vehicle software control platform converts the received CAN messages into the current cylinder drive flow and sends them to the excavator hydraulic system simulation module in the dynamic simulation calculation software platform through the joint simulation interface.

[0035] The excavator hydraulic system simulation module transmits the hydraulic parameters of the system when it is working to the excavator kinematic system simulation module to control the simulated movement of the excavator mechanical model.

[0036] The soil resistance simulation module simulates the real soil resistance and acts on the excavator kinematic system simulation module to simulate the application of soil resistance load and obtain the bucket cylinder pressure of the excavator hydraulic system simulation module at this time.

[0037] The dynamics simulation software platform transmits the simulated bucket cylinder pressure results to the vehicle software control platform via a co-simulation interface. The vehicle software control platform converts the cylinder pressure parameters obtained from the dynamics simulation software platform into control current parameters for the proportional relief valve. Using Peak-CAN, the cylinder pressure and proportional relief valve control current parameters are transmitted to the vehicle control unit via the CAN bus.

[0038] The vehicle control unit uses the cylinder pressure received from the vehicle software control platform as the target pressure, and uses the first pressure sensor as the feedback pressure to perform proportional-integral-differential algorithm regulation. It calculates the error between the current cylinder pressure solved in the joint simulation system and the proportional relief valve inlet pressure. The proportional part is adjusted according to the current error, the integral part eliminates the steady-state error of the system, and the differential part predicts the changing trend of the error and corrects it, so that the control current of the proportional relief valve is adjusted in real time. The current value sent by the PWM generating port of the vehicle control unit is further adjusted to control the valve core opening of the proportional relief valve to adjust its inlet pressure, thereby completing the load loading of the excavator power system.

[0039] As a further optimization, the excavator power system further includes a drive motor. The drive motor is mechanically connected to the main pump via a spline sleeve, and the main pump drives the pilot pump via a gear transmission.

[0040] As a further optimization, the proportional relief valve is a pilot-operated proportional relief valve.

[0041] By adopting the above technical solution, the present invention can achieve the following technical effects: This embodiment of a real-time operating load simulation system for a hydraulic excavator power system is a unique semi-physical real-time hydraulic load loading system. It establishes a real-time interactive system between the excavator system simulation model and the actual excavator power system. Using a simulated soil resistance model, it determines the cylinder pressure caused by the actual excavation load resistance, which is then used to apply real-time pressure to the proportional relief valve. This ensures that the load responds to the actual flow rate of the excavator during operation, ensuring the dynamic characteristics of the actuator flow, pressure, and coupling during the actual measurement of the entire machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the specific embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0043] Figure 1 It is a structural diagram of the real-time working load simulation system.

[0044] Figure 2 It is a structural diagram of working condition one.

[0045] Figure 3 It is the structural diagram of working condition 2.

[0046] Markings in the figure: 1-excavator power system, 2-load loading hydraulic system, 3-vehicle control unit, 4-joint simulation system, 11-pilot hydraulic control handle, 12-signal control valve, 13-multi-way valve, 14-drive motor, 15-main pump, 16-pilot pump, 17-oil tank, 21-first flow sensor, 22-second flow sensor, 23-first pressure sensor, 24-second pressure sensor, 25-one-way valve liquid bridge, 251-first one-way valve, 252-second one-way valve, 253-third one-way valve, 254-fourth one-way valve, 26-pilot proportional relief valve, 41-vehicle software control platform, 42-dynamic simulation calculation software platform, 421-excavator hydraulic system simulation module, 422-excavator kinematic system simulation module, 423-soil resistance simulation module. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0048] See also Figures 1 to 3 The first embodiment of the present invention provides a real-time working condition load simulation system of a hydraulic excavator power system, which includes an excavator power system 1, a load loading hydraulic system 2, a vehicle control unit 3 communicatively connected to the load loading hydraulic system 2, and a joint simulation system 4 communicatively connected to the vehicle control unit 3. The excavator power system 1 includes an oil tank 17, a main pump 15 and a pilot pump 16 connected to the oil tank 17, a pilot hydraulic control handle 11 connected to the pilot pump 16, a signal control valve 12 connected to the pilot hydraulic control handle 11, and a multi-way valve 13 connected to the main pump 15 and the signal control valve 12. Preferably, the excavator power system 1 also includes a drive motor 14. The drive motor 14 is mechanically connected to the main pump 15 through a spline sleeve, and the main pump 15 drives the pilot pump 16 to work through a gear transmission. The main pump 15 is used to supply oil to the multi-way valve 13. The signal control valve 12 is used to provide secondary pilot pressure to control the opening of each valve port inside the multi-way valve 13.

[0049] The load applying hydraulic system 2 includes a one-way valve fluid bridge 25 coupled to the multi-way valve 13 and a proportional relief valve coupled to the one-way valve fluid bridge 25 .

[0050] The one-way valve liquid bridge 25 includes a first one-way valve 251 and a second one-way valve 252 connected at their outlets, and a third one-way valve 253 and a fourth one-way valve 254 connected at their inlets. The outlet of the third one-way valve 253 is connected to the inlet of the first one-way valve 251. The outlet of the fourth one-way valve 254 is connected to the inlet of the second one-way valve 252.

[0051] The port A of the multi-way valve 13 is connected between the first one-way valve 251 and the third one-way valve 253 . The port B of the multi-way valve 13 is connected between the second one-way valve 252 and the fourth one-way valve 254 .

[0052] The inlet of the proportional relief valve is connected to the outlet of the first one-way valve 251 . The outlet of the proportional relief valve is connected to the inlet of the third one-way valve 253 .

[0053] On the basis of the above embodiment, in an optional embodiment of the present invention, as Figures 1 to 3 As shown, the load applying hydraulic system 2 further includes a first flow sensor 21 and a first pressure sensor 23 connected to the A port, and a second flow sensor 22 and a second pressure sensor 24 connected to the B port.

[0054] The vehicle control unit 3 is communicatively connected to the first flow sensor 21 , the second flow sensor 22 , the first pressure sensor 23 , the second pressure sensor 24 , the first one-way valve 251 , the second one-way valve 252 , the third one-way valve 253 , the fourth one-way valve 254 , and the proportional relief valve.

[0055] The hydraulic load simulation system of this embodiment achieves loading by converting a preset load force into a corresponding proportional relief valve control current, thereby driving the proportional relief valve's spool opening and thereby controlling the proportional relief valve's inlet pressure. In an alternative embodiment of the present invention, the proportional relief valve is a pilot-operated proportional relief valve 26. This pilot-operated proportional relief valve 26 incorporates a built-in maximum pressure protection device, which provides oil return protection when system pressure exceeds a certain level.

[0056] The hydraulic cylinder of the excavator can flow in both directions, while the proportional relief valve can only flow in one direction. This embodiment solves the problem caused by the change of the oil flow direction of the multi-way valve 13 outlet due to the switching of the working conditions of the excavator through the one-way valve liquid bridge 25.

[0057] Specifically, in the connection structure of the hydraulic pipeline of this embodiment, the main pump 15 and the pilot pump 16 are connected to the oil tank 17 through hydraulic pipes to absorb oil. The main pump 15 is connected to the multi-way valve 13 pipeline for supplying oil to the multi-way valve 13. The pilot pump 16 is connected to the pilot hydraulic control handle 11 pipeline to supply oil to the pilot hydraulic control handle 11. The pilot hydraulic control handle 11 is connected to the signal control valve 12 pipeline. The signal control valve 12 is connected to the multi-way valve 13 pipeline. The signal control valve 12 provides secondary pilot pressure for controlling the opening of each valve port inside the multi-way valve 13. The hydraulic piping connections of the one-way valve bridge 25 are specifically connected: the outlet of the first one-way valve 251 is connected to the outlet of the second one-way valve 252, the inlet of the second one-way valve 252 is connected to the outlet of the fourth one-way valve 254, the inlet of the third one-way valve 253 is connected to the inlet of the fourth one-way valve 254, and the outlet of the third one-way valve 253 is connected to the inlet of the first one-way valve 251. Line A at the outlet of the multi-way valve 13 is connected via a tee to the center between the first and third one-way valves 251 and 253, and Line B at the outlet of the multi-way valve 13 is connected via a tee to the center between the second and fourth one-way valves 252 and 254. The first and second flow sensors 21 and 22 are hydraulically connected via pipes to the multi-way valve 13 and Lines A and B of the one-way valve bridge 25. Meanwhile, the first and second pressure sensors 23 and 24 are connected via tees to Lines A and B, respectively.

[0058] The present embodiment provides a real-time working load simulation system for a hydraulic excavator power system. The load loading hydraulic system 2 in the system replaces the actuator cylinder on the original excavator. The vehicle control unit 3 and the joint simulation system 4 are combined to simulate the actual soil load to realize the pressure control of the proportional relief valve and thus load the excavator system.

[0059] The joint simulation system 4 includes a vehicle software control platform 41 and a dynamics simulation calculation software platform 42. The dynamics simulation calculation software platform 42 includes an excavator hydraulic system simulation module 421, an excavator kinematic system simulation module 422, and a soil resistance simulation module 423.

[0060] The vehicle software control platform 41 is used to analyze the analog electrical signals of the first one-way valve 251, the second one-way valve 252, the third one-way valve 253, and the fourth one-way valve 254 from the vehicle control unit 3, and send the analyzed signal results to the dynamic simulation calculation software platform 42.

[0061] The dynamics simulation software platform 42 is used to simulate the actual operation of an excavator. Specifically, the excavator hydraulic system simulation module 421 simulates the excavator's hydraulic drive system. The excavator kinematic system simulation module 422 simulates the excavator's mechanical structure and motion. The soil resistance simulation module 423 simulates real soil to simulate the application of soil loads and transmits the pressure of the cylinder drive chamber in the excavator hydraulic system simulation module 421 to the vehicle software control platform 41 in real time.

[0062] The dynamics simulation software platform 42 sends the simulation results to the vehicle software control platform 41. The vehicle software control platform 41 converts the simulation results into control parameters and sends them to the vehicle control unit 3. The vehicle control unit 3 then controls the load-loading hydraulic system 2 to achieve information exchange and control between the simulation and hardware.

[0063] Preferably, the vehicle software control platform 41 and the dynamics simulation calculation software platform 42 are communicatively connected via a joint simulation interface. Specifically, in this embodiment, the dynamics simulation calculation software platform 42 and the vehicle software control platform 41 are jointly simulated using a joint simulation interface. The dynamics simulation calculation software platform 42 sends the simulation results to the vehicle software control platform 41 via the simulation interface. The vehicle software control platform 41 converts the simulation results into control parameters and sends them to the vehicle control unit 3 via the CAN bus, and then controls the load loading hydraulic system 2 through the vehicle control unit 3, ultimately realizing information interaction and control between simulation and hardware. The above simulation software is used in this embodiment, but is not limited to the software mentioned here.

[0064] In the joint simulation system 4, real-time animation can be added to complete the simulation results by receiving real-time flow signals from the hardware system. The driver can use the real-time animation to view the real-time movement of the excavator under control. In other words, any test condition can be realized based on the driver's operation.

[0065] Furthermore, to address the impact of additional pressure generated during the operation of complex hydraulic systems on the proportional relief valve inlet pressure, closed-loop control of the proportional relief valve has been added to the control strategy. Specifically, the vehicle control unit 3 utilizes a proportional-integral-differential algorithm for closed-loop control of the proportional relief valve, calculating the error between the current cylinder pressure (solved in the simulation) and the proportional relief valve inlet pressure. The proportional component adjusts based on the current error, the integral component eliminates the system's steady-state error, and the differential component predicts and corrects the error's changing trend. This allows for real-time adjustment of the proportional relief valve's control current, further adjusting the proportional relief valve's spool opening to align its inlet pressure with the target loading pressure.

[0066] It should be noted that the semi-physical load simulation loading system of this embodiment is not limited to the load loading of excavators, but is applicable to any engineering machinery that adopts a hydraulically driven working actuator device.

[0067] The excavator power system 1 of the embodiment of the present invention provides hydraulic flow to the load loading hydraulic system 2. When the system is in operation, the drive motor 14 drives the main pump 15 and the pilot pump 16 to output flow. When the driver operates the pilot hydraulic control handle 11 to output the pilot control flow to the signal control valve 12, the signal control valve 12 outputs the corresponding action control flow signal to the multi-way valve 13 according to the input flow of the pilot hydraulic control handle 11, and the multi-way valve 13 outputs the driving flow to the load loading hydraulic system 2. The first flow sensor 21 is used to detect the flow of the A port pipeline of the multi-way valve 13. The first pressure sensor 23 is used to detect the pressure of the A port pipeline of the multi-way valve 13. The second flow sensor 22 is used to detect the flow of the B outlet pipeline of the multi-way valve 13. The second pressure sensor 24 is used to detect the pressure of the B outlet pipeline of the multi-way valve 13. The one-way valve liquid bridge 25 is used to ensure that the outlet flow of the multi-way valve 13 reaches the inlet of the pilot proportional relief valve 26. The pilot proportional relief valve 26 adjusts the valve core opening by receiving the control electrical signal of the vehicle control unit 3 to apply pressure to the one-way valve liquid bridge 25 for loading the load end.

[0068] The vehicle control unit 3 of the embodiment of the present invention is configured to receive analog electrical signals from the first flow sensor 21, the second flow sensor 22, the first pressure sensor 23, and the second pressure sensor 24 in the load-loading hydraulic system 2 and transmit them to the vehicle software control platform 41. Simultaneously, it receives control parameters from the vehicle software control platform 41 and transmits control signals to the pilot-operated proportional relief valve 26 to adjust the inlet pressure of the pilot-operated proportional relief valve 26 to achieve load-side loading. Specifically, in this embodiment, the first flow sensor 21, the second flow sensor 22, the first pressure sensor 23, and the second pressure sensor 24 are electrically connected to the vehicle control unit 3 and transmit the current and current signals they collect to the analog signal receiving port of the vehicle control unit 3. The vehicle control unit 3 is electrically connected to the pilot-operated proportional relief valve 26 and transmits a control current signal via a PWM generator port on the vehicle control unit 3 to control the valve core opening of the pilot-operated proportional relief valve 26, thereby adjusting the inlet pressure of the pilot-operated proportional relief valve 26.

[0069] The vehicle software control platform 41 in the joint simulation system 4 of an embodiment of the present invention is used to parse the analog electrical signals of the first one-way valve 251, the second one-way valve 252, the third one-way valve 253, and the fourth one-way valve 254 from the vehicle control unit 3, and send the parsed signal results to the dynamic simulation calculation software platform 42 through the joint simulation interface.

[0070] The dynamic simulation calculation software platform 42 in the joint simulation system 4 of the embodiment of the present invention is used to simulate the actual operation of the excavator, wherein the excavator hydraulic system simulation module 421 is used to simulate the hydraulic drive system of the excavator, the excavator kinematic system simulation module 422 is used to simulate the mechanical structure and movement of the excavator, and the soil resistance simulation module 423 simulates real soil for simulating the application of soil load, and sends the pressure of the cylinder drive chamber in the excavator hydraulic system simulation module 421 to the vehicle software control platform 41 through the joint simulation interface in real time.

[0071] The vehicle software control platform 41 converts the load pressure signal into control signal parameters for the pilot-operated proportional relief valve 26 and sends them to the vehicle control unit 3. The vehicle control unit 3 converts the received control parameters into control signals for controlling the valve core opening of the pilot-operated proportional relief valve 26, thereby controlling the inlet pressure of the pilot-operated proportional relief valve 26.

[0072] In this embodiment, the communication connection scheme is as follows: the vehicle control unit 3 communicates with the vehicle software control platform 41 via the CAN bus using Peak-CAN. Specifically, the vehicle software control platform 41 converts the results of the joint simulation with the dynamics simulation software platform 42 into a control signal for the pilot-operated proportional relief valve 26, and transmits this signal to the vehicle control unit 3 via the CAN bus using Peak-CAN.

[0073] In this embodiment, information exchange within the co-simulation system 4 proceeds as follows: During simulation execution, the excavator hydraulic system simulation module 421 within the dynamics simulation software platform 42 transmits the current operating hydraulic parameters to the excavator kinematic system simulation module 422, thereby controlling the simulated motion of the excavator mechanical model. The soil resistance simulation module 423 simulates the actual soil resistance acting on the excavator kinematic system simulation module 422, thereby applying a simulated soil resistance load. The dynamics simulation software platform 42 transmits the simulated pressure results for each cylinder drive chamber to the vehicle software control platform 41 via the co-simulation interface.

[0074] The multi-way valve 13 is provided with a control port, an oil inlet, an oil outlet, a port A (i.e., the A connection port), and a port B (i.e., the B connection port). The multi-way valve 13 is configured such that the control port can control the oil inlet to switch between connecting to either port A or port B. The port A or port B that is not connected to the oil inlet is switched to connect to the oil outlet. The control port is connected to the signal control valve 12. The oil inlet is connected to the main pump 15. The oil outlet is connected to the oil tank 17.

[0075] The bucket excavation load is the most typical in the excavation working condition of the excavator. The following is an example of bucket cylinder load loading. The following includes two working conditions: bucket excavation inward retraction and bucket unloading outward retraction, but is not limited to the following working conditions: like Figure 2 As shown, when the bucket of the excavator is in the retracted working condition, the A port of the multi-way valve 13 is outgoing oil, the B port is returning oil, and the loading pressure of the pilot-operated proportional relief valve 26 is the driving pressure of the rodless chamber of the excavator.

[0076] At this point, the excavator power system 1 is operating. The drive motor 14 drives the main pump 15 and pilot pump 16 to draw oil from the oil tank 17 and deliver it to the multi-way valve 13 and the pilot hydraulic control handle 11, respectively. The oil is driven through port A of the multi-way valve 13, then passes through the first flow sensor 21 and the first check valve 251 in the check valve bridge 25 to the pilot proportional relief valve 26. The oil then flows through the pilot proportional relief valve 26, the fourth check valve 254 and the second flow sensor 22 to port B of the multi-way valve 13, and then returns to the oil tank 17.

[0077] When the system is running, the vehicle control unit 3 collects the current signals fed back by the first pressure sensor 23 and the first flow sensor 21 in real time, and sends them to the vehicle software control platform 41 via the CAN bus using Peak-CAN.

[0078] The parsing program written in the vehicle software control platform 41 converts the received CAN message into the current cylinder drive flow and sends it to the excavator hydraulic system simulation module 421 in the dynamic simulation calculation software platform 42 through the joint simulation interface.

[0079] The excavator hydraulic system simulation module 421 transmits the hydraulic parameters of the system when it is working to the excavator kinematic system simulation module 422 to control the excavator mechanical model to perform simulated movement.

[0080] The soil resistance simulation module 423 simulates the actual soil resistance and acts on the excavator kinematic system simulation module 422 to simulate the application of soil resistance load and obtain the bucket cylinder pressure of the excavator hydraulic system simulation module 421 at this time.

[0081] The dynamics simulation software platform 42 transmits the simulated bucket cylinder pressure results to the vehicle software control platform 41 via the co-simulation interface. The vehicle software control platform 41 converts the cylinder pressure parameters obtained from the dynamics simulation software platform 42 into control current parameters for the pilot-operated proportional relief valve 26. Using Peak-CAN, the cylinder pressure and the control current parameters for the pilot-operated proportional relief valve 26 are transmitted to the vehicle control unit 3 via the CAN bus.

[0082] The vehicle control unit 3 uses the cylinder pressure received from the vehicle software control platform 41 as the target pressure and the first pressure sensor 23 as the feedback pressure to perform a proportional-integral-differential algorithm. This algorithm calculates the error between the current cylinder pressure calculated in the co-simulation system 4 and the proportional relief valve inlet pressure. The proportional component adjusts based on the current error, the integral component eliminates the system's steady-state error, and the differential component predicts and corrects the error's changing trend. This allows for real-time adjustments to the control current of the pilot-operated proportional relief valve 26. The current value sent by the PWM generator port of the vehicle control unit 3 is further adjusted to control the valve core opening of the pilot-operated proportional relief valve 26, adjusting its inlet pressure and thus completing the load loading of the excavator power system 1.

[0083] like Figure 3 As shown, when the bucket of the excavator is in the outward-turning working condition, the B port of the multi-way valve 13 is outgoing oil, the A port is returning oil, and the loading pressure of the pilot-operated proportional relief valve 26 is the driving pressure of the rod chamber of the excavator.

[0084] At this time, the excavator power system 1 is running, and the drive motor 14 drives the main pump 15 and the pilot pump 16 to suck oil from the oil tank 17 and output the oil to the multi-way valve 13 and the pilot hydraulic control handle 11 respectively, driving the oil circuit to output from the B port of the multi-way valve 13, and then through the second flow sensor 22 and the second one-way valve 252 in the one-way valve liquid bridge 25 to the pilot proportional relief valve 26, and then the oil passing through the pilot proportional relief valve 26 flows through the third one-way valve 253 and the first flow sensor 21 to the A port of the multi-way valve 13 to return the oil to the oil tank 17.

[0085] When the system is running, the vehicle control unit 3 collects the current signals fed back by the second pressure sensor 24 and the second flow sensor 22 in real time, and sends them to the vehicle software control platform 41 via the CAN bus using Peak-CAN.

[0086] The parsing program written in the vehicle software control platform 41 converts the received CAN message into the current cylinder drive flow and sends it to the excavator hydraulic system simulation module 421 in the dynamic simulation calculation software platform 42 through the joint simulation interface.

[0087] The excavator hydraulic system simulation module 421 transmits the hydraulic parameters of the system when it is working to the excavator kinematic system simulation module 422 to control the simulated movement of the excavator mechanical model.

[0088] The soil resistance simulation module 423 simulates the actual soil resistance and acts on the excavator kinematic system simulation module 422 to simulate the application of soil resistance load and obtain the bucket cylinder pressure of the excavator hydraulic system simulation module 421 at this time.

[0089] The dynamics simulation software platform 42 transmits the simulated bucket cylinder pressure results to the vehicle software control platform 41 via the co-simulation interface. The vehicle software control platform 41 converts the cylinder pressure parameters obtained from the dynamics simulation software platform 42 into control current parameters for the pilot-operated proportional relief valve 26. Using Peak-CAN, the cylinder pressure and the control current parameters for the pilot-operated proportional relief valve 26 are transmitted to the vehicle control unit 3 via the CAN bus.

[0090] The vehicle control unit 3 uses the cylinder pressure received from the vehicle software control platform 41 as the target pressure, and uses the first pressure sensor 23 as the feedback pressure to perform proportional-integral-differential algorithm control, and calculates the error between the current cylinder pressure solved in the joint simulation system 4 and the proportional relief valve inlet pressure. The proportional part is adjusted according to the current error, the integral part eliminates the steady-state error of the system, and the differential part predicts the change trend of the error and corrects it, so that the control current of the pilot proportional relief valve 26 is adjusted in real time, and the current value sent by the PWM generating port of the vehicle control unit 3 is further adjusted to control the valve core opening of the pilot proportional relief valve 26 to adjust its inlet pressure, thereby completing the load loading of the excavator power system 1.

[0091] This embodiment of a real-time operating load simulation system for a hydraulic excavator power system is a unique semi-physical real-time hydraulic load loading system. It establishes a real-time interactive system between the excavator system simulation model and the actual excavator power system. Using a simulated soil resistance model, it determines the cylinder pressure caused by the actual excavation load resistance, which is then used to apply real-time pressure to the proportional relief valve. This ensures that the load responds to the actual flow rate of the excavator during operation, ensuring the dynamic characteristics of the actuator flow, pressure, and coupling during the actual measurement of the entire machine.

[0092] This embodiment uses a semi-physical load loading system for an excavator built through a physical power system, a load loading system and a joint simulation system 4 to solve the problem that the traditional hydraulic loading platform adopts a static curve load loading method and cannot reproduce the complex coupling relationship between pressure and flow during the actual operation of the excavator. This semi-physical hydraulic load real-time loading system uses a joint simulation model to solve the actual load and loads it to the proportional relief valve on the hydraulic load loading module in real time, thereby realizing precise loading of the excavator power system 1 and ensuring the coupling characteristic relationship between the flow and load pressure of the excavator system during load loading. It can respond to the actual load according to the output flow of the excavator system, thereby improving the accuracy and reliability of the load loading and providing a reliable test system for the whole machine power system test before the excavator leaves the factory.

[0093] This embodiment takes into account the impact of the additional pressure brought by the complex hydraulic system on the pressure loading end of the proportional relief valve. By setting the load result of the simulation model to the target pressure and the pressure at the inlet of the proportional relief valve for proportional-integral-differential algorithm control, the accuracy and reliability of load loading are further improved.

[0094] Obviously, the above detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but is merely a preferred embodiment of the present invention, not all embodiments, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and variations. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work, any modifications, equivalent substitutions, improvements, etc., are within the scope of protection of the present invention.

Claims

1. A real-time working load simulation system for a hydraulic excavator power system, characterized in that: It comprises an excavator power system (1), a load-loading hydraulic system (2), a vehicle control unit (3) communicatively connected to the load-loading hydraulic system (2), and a joint simulation system (4) communicatively connected to the vehicle control unit (3); The excavator power system (1) includes an oil tank (17), a main pump (15) and a pilot pump (16) connected to the oil tank (17), a pilot hydraulic control handle (11) connected to the pilot pump (16), a signal control valve (12) connected to the pilot hydraulic control handle (11), and a multi-way valve (13) connected to the main pump (15) and the signal control valve (12). The load-loading hydraulic system (2) comprises a one-way valve liquid bridge (25) coupled to the multi-way valve (13), and a proportional overflow valve coupled to the one-way valve liquid bridge (25); the one-way valve liquid bridge (25) comprises a first one-way valve (251) and a second one-way valve (252) connected at their outlets, and a third one-way valve (253) and a fourth one-way valve (254) connected at their inlets; the outlet of the third one-way valve (253) is connected to the inlet of the first one-way valve (251); the outlet of the fourth one-way valve (254) is connected to the inlet of the second one-way valve (252); Port A of the multi-way valve (13) is connected between the first one-way valve (251) and the third one-way valve (253); port B of the multi-way valve (13) is connected between the second one-way valve (252) and the fourth one-way valve (254); The inlet of the proportional relief valve is connected to the outlet of the first one-way valve (251); and the outlet of the proportional relief valve is connected to the inlet of the third one-way valve (253).

2. A real-time working load simulation system for a hydraulic excavator power system according to claim 1, characterized in that: The load-loading hydraulic system (2) further includes a first flow sensor (21) and a first pressure sensor (23) connected to port A, and a second flow sensor (22) and a second pressure sensor (24) connected to port B; The vehicle control unit (3) is communicatively connected to the first flow sensor (21), the second flow sensor (22), the first pressure sensor (23), the second pressure sensor (24), the first one-way valve (251), the second one-way valve (252), the third one-way valve (253), the fourth one-way valve (254), and the proportional relief valve.

3. A real-time working load simulation system for a hydraulic excavator power system according to claim 2, characterized in that: The joint simulation system (4) includes a vehicle software control platform (41) and a dynamics simulation calculation software platform (42); the dynamics simulation calculation software platform (42) includes an excavator hydraulic system simulation module (421), an excavator kinematic system simulation module (422), and a soil resistance simulation module (423); The vehicle software control platform (41) is used to analyze the analog electrical signals of the first one-way valve (251), the second one-way valve (252), the third one-way valve (253), and the fourth one-way valve (254) from the vehicle control unit (3), and send the analyzed signal results to the dynamic simulation calculation software platform (42); The dynamic simulation calculation software platform (42) is used to simulate the actual operation of the excavator; wherein, the excavator hydraulic system simulation module (421) is used to simulate the hydraulic drive system of the excavator; the excavator kinematic system simulation module (422) is used to simulate the mechanical structure and movement of the excavator; the soil resistance simulation module (423) is used to simulate real soil for simulating the application of soil load, and sends the pressure of the oil cylinder drive chamber in the excavator hydraulic system simulation module (421) to the vehicle software control platform (41) in real time; The dynamic simulation calculation software platform (42) sends the simulation results to the vehicle software control platform (41); the vehicle software control platform (41) converts the simulation results into control parameters and sends them to the vehicle control unit (3), and then controls the load loading hydraulic system (2) through the vehicle control unit (3) to realize information interaction and control between simulation and hardware.

4. A real-time working load simulation system for a hydraulic excavator power system according to claim 3, characterized in that: The vehicle software control platform (41) converts the load pressure signal into a control parameter of the proportional relief valve and sends it to the vehicle control unit (3); The vehicle control unit (3) is used to receive analog electrical signals from a first flow sensor (21), a second flow sensor (22), a first pressure sensor (23), and a second pressure sensor (24) in the load loading hydraulic system (2), and send them to the vehicle software control platform (41). At the same time, it receives control parameters of the vehicle software control platform (41) and sends a control signal to the proportional relief valve to adjust the valve core opening of the proportional relief valve, thereby controlling the inlet pressure of the proportional relief valve to achieve load end loading.

5. The real-time working load simulation system of a hydraulic excavator power system according to claim 3, characterized in that: The vehicle control unit (3) and the vehicle software control platform (41) are connected via CAN bus communication using Peak-CAN; The vehicle software control platform (41) and the dynamics simulation calculation software platform (42) are communicatively connected via a joint simulation interface; The vehicle control unit (3) uses the proportional-integral-differential algorithm to perform closed-loop control of the proportional relief valve and calculates the error between the current cylinder pressure solved in the simulation and the proportional relief valve inlet pressure; wherein the proportional part is adjusted according to the current error, the integral part eliminates the steady-state error of the system, and the differential part predicts the changing trend of the error and makes corrections, so that the control current of the proportional relief valve is adjusted in real time to further adjust the valve core opening of the proportional relief valve so that its inlet pressure is consistent with the target loading pressure.

6. A real-time working load simulation system for a hydraulic excavator power system according to any one of claims 1 to 5, characterized in that: The multi-way valve (13) is provided with a control port, an oil inlet, an oil discharge port, a port A, and a port B; the multi-way valve (13) is configured such that the control port can control the oil inlet to switch and connect to one of the port A and the port B; the port A and the port B that is not connected to the oil inlet is switched and connected to the oil discharge port; the control port is connected to the signal control valve (12); the oil inlet is connected to the main pump (15); and the oil discharge port is connected to the oil tank (17).

7. A real-time working load simulation system for a hydraulic excavator power system according to claim 6, characterized in that: When the bucket of the excavator is in the retracted working condition, the A port of the multi-way valve (13) is oil outlet and the B port is oil return, and the loading pressure of the proportional relief valve is the driving pressure of the rodless chamber of the excavator; At this time, the excavator power system (1) is running, the drive motor (14) drives the main pump (15) and the pilot pump (16) to suck oil from the oil tank (17) and output the oil to the multi-way valve (13) and the pilot hydraulic control handle (11) respectively, and the driving oil circuit is output from the A port of the multi-way valve (13), and then passes through the first flow sensor (21) and the first one-way valve (251) in the one-way valve liquid bridge (25) to the proportional relief valve; then the oil passing through the proportional relief valve flows through the fourth one-way valve (254) and the second flow sensor (22) to the B port of the multi-way valve (13) to return the oil to the oil tank (17); When the system is running, the vehicle control unit (3) collects the current signals fed back by the first pressure sensor (23) and the first flow sensor (21) in real time, and transmits them to the vehicle software control platform (41) via the CAN bus using Peak-CAN; The vehicle software control platform (41) converts the received CAN message into the current cylinder drive flow and sends it to the excavator hydraulic system simulation module (421) in the dynamic simulation calculation software platform (42) through the joint simulation interface; The excavator hydraulic system simulation module (421) transmits the hydraulic parameters of the system when it is working to the excavator kinematic system simulation module (422) to control the excavator mechanical model to perform simulated movement; The soil resistance simulation module (423) simulates the actual soil resistance and acts on the excavator kinematic system simulation module (422) to simulate the application of the soil resistance load and obtain the bucket cylinder pressure of the excavator hydraulic system simulation module (421) at this time; The dynamic simulation calculation software platform (42) transmits the pressure result of the bucket cylinder simulated at this time to the vehicle software control platform (41) through the joint simulation interface; the vehicle software control platform (41) converts the cylinder pressure parameter obtained from the dynamic simulation calculation software platform (42) into the control current parameter of the proportional relief valve, and uses Peak-CAN to transmit the cylinder pressure and the control current parameter of the proportional relief valve to the vehicle control unit (3) through the CAN bus; The vehicle control unit (3) uses the cylinder pressure received from the vehicle software control platform (41) as the target pressure, and uses the first pressure sensor (23) as the feedback pressure to perform proportional-integral-differential algorithm control, and calculates the error between the current cylinder pressure solved in the joint simulation system (4) and the proportional relief valve inlet pressure; the proportional part is adjusted according to the current error, the integral part eliminates the steady-state error of the system, and the differential part predicts the error change trend and corrects it, so that the control current of the proportional relief valve is adjusted in real time, and the current value sent by the PWM generating port of the vehicle control unit (3) is further adjusted to control the valve core opening of the proportional relief valve to adjust its inlet pressure, thereby completing the load loading of the excavator power system (1).

8. The real-time working load simulation system of a hydraulic excavator power system according to claim 6, characterized in that: When the bucket of the excavator is in the outward-turning working condition, the B port of the multi-way valve (13) is outgoing oil, and the A port is returning oil. The loading pressure of the proportional relief valve is the driving pressure of the rod chamber of the excavator. At this time, the excavator power system (1) is running, the drive motor (14) drives the main pump (15) and the pilot pump (16) to suck oil from the oil tank (17) and output the oil to the multi-way valve (13) and the pilot hydraulic control handle (11) respectively, and the driving oil circuit is output from the B port of the multi-way valve (13), and then passes through the second flow sensor (22) and the second one-way valve (252) in the one-way valve liquid bridge (25) to the proportional relief valve, and then the oil passing through the proportional relief valve flows through the third one-way valve (253) and the first flow sensor (21) to the A port of the multi-way valve (13) to return the oil to the oil tank (17); When the system is running, the vehicle control unit (3) collects the current signal fed back by the second pressure sensor (24) and the second flow sensor (22) in real time, and sends the current signal to the vehicle software control platform (41) via the CAN bus using Peak-CAN; The vehicle software control platform (41) converts the received CAN message into the current cylinder drive flow and sends it to the excavator hydraulic system simulation module (421) in the dynamic simulation calculation software platform (42) through the joint simulation interface; The excavator hydraulic system simulation module (421) transmits the hydraulic parameters of the system when it is working to the excavator kinematic system simulation module (422) to control the simulated movement of the excavator mechanical model; The soil resistance simulation module (423) simulates the actual soil resistance and acts on the excavator kinematic system simulation module (422) to simulate the application of the soil resistance load and obtain the bucket cylinder pressure of the excavator hydraulic system simulation module (421) at this time; The dynamic simulation calculation software platform (42) transmits the pressure result of the bucket cylinder simulated at this time to the vehicle software control platform (41) through the joint simulation interface; the vehicle software control platform (41) converts the cylinder pressure parameter obtained from the dynamic simulation calculation software platform (42) into the control current parameter of the proportional relief valve, and uses Peak-CAN to transmit the cylinder pressure and the control current parameter of the proportional relief valve to the vehicle control unit (3) through the CAN bus; The vehicle control unit (3) uses the cylinder pressure received from the vehicle software control platform (41) as the target pressure, and uses the first pressure sensor (23) as the feedback pressure to perform proportional-integral-differential algorithm control, and calculates the error between the current cylinder pressure solved in the joint simulation system (4) and the proportional relief valve inlet pressure. The proportional part is adjusted according to the current error, the integral part eliminates the steady-state error of the system, and the differential part predicts the change trend of the error and corrects it, so that the control current of the proportional relief valve is adjusted in real time. The current value sent by the PWM generating port of the vehicle control unit (3) is further adjusted to control the valve core opening of the proportional relief valve to adjust its inlet pressure, thereby completing the load loading of the excavator power system (1).

9. A real-time working load simulation system for a hydraulic excavator power system according to any one of claims 1 to 5, characterized in that: The excavator power system (1) further includes a drive motor (14); the drive motor (14) is mechanically connected to a main pump (15) via a spline sleeve, and the main pump (15) drives a pilot pump (16) to operate via a gear transmission.

10. A real-time working load simulation system for a hydraulic excavator power system according to any one of claims 1 to 5, characterized in that: The proportional relief valve is a pilot-operated proportional relief valve (26).

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