A hydraulic drive dynamic performance verification test device and method

Abstract

This invention discloses a hydraulic drive dynamic performance verification test device and method, belonging to the field of hydraulic robot testing technology. The device includes a hydraulic system, an inverted pendulum hardware system, and a data acquisition and feedback system. The hydraulic system includes a pump station module and a motor module. The pendulum rod and slider in the inverted pendulum mechanism are detachable, allowing switching between full-drive and under-drive test modes by assembling and disassembling the pendulum rod. The data acquisition and feedback system includes a main control computer, a motion control card, and a servo motor driver, responsible for data acquisition and command issuance. This verification method sequentially completes the overall nonlinear modeling of the device, displacement tracking test, pendulum start-up test, steady-state zero-position test, and pulse disturbance rejection test, achieving a comprehensive quantitative evaluation of the device model accuracy, transient agility, steady-state control accuracy, and anti-interference capability. This invention can reproduce the nonlinear characteristics of hydraulic and mechanical coupling, offers convenient switching between operating conditions, and has a complete test system, providing reliable experimental support for optimizing the control strategy of hydraulically driven robots.

Description

Technical Field

[0001] This invention relates to the field of hydraulic performance testing technology, specifically to a hydraulic drive dynamic performance verification test device and method. Background Technology

[0002] The performance of a robot's drive system directly determines its operational accuracy, dynamic response speed, and adaptability to various scenarios. Currently, the mainstream robot drive methods are mainly divided into two categories: electric motor drive and hydraulic drive. Among them, electric motor drive, with its advantages of compact transmission structure, high control precision, sensitive dynamic response (millisecond-level start-stop and speed adjustment), and low nonlinear interference, is widely used in scenarios such as light-load, high-precision operations (e.g., industrial assembly robots, collaborative robots); while hydraulic drive, due to its characteristics of high torque output, high power density, and strong resistance to load impact, has irreplaceable application value in heavy-load, harsh working conditions (e.g., mining robots, heavy-duty handling robots, underwater robots).

[0003] However, the widespread adoption and performance optimization of hydraulic drives in the robotics field face significant technical bottlenecks. Compared to electric motor drives, hydraulic drive systems are affected by physical characteristics such as fluid viscosity, throttling losses, and oil compressibility, making hydraulic actuators prone to dead zones and creeping phenomena at low speeds. Furthermore, hydraulic systems exhibit response lag, pressure shocks, and flow fluctuations during high-frequency reversals, resulting in strong nonlinear characteristics. These issues directly impact the robot's operational stability, accuracy, and dynamic following performance, becoming core obstacles limiting the expansion of hydraulically driven robots into high-precision, high-dynamic-response scenarios.

[0004] To address the aforementioned technical shortcomings of hydraulic drive systems, it is necessary to conduct operational condition simulations, performance characterization, and optimization verification through a targeted testing platform. However, existing hydraulic testing platforms cannot meet the testing requirements of dedicated hydraulic drive systems for robots. Specifically:

[0005] First, existing hydraulic testing platforms are designed with large hydraulic equipment (such as construction machinery and industrial hydraulic units) as the core, which has problems such as large structure and complicated disassembly and assembly processes, making it difficult to adapt to the testing scenarios of miniaturized hydraulic robots. Moreover, their testing objectives focus on the static characteristics of hydraulic systems under steady-state operating conditions, such as leakage and oil compression characteristics, without fully considering the dynamic characteristics required by hydraulic robots in miniaturized and precise operations. At the same time, the platform structure is fixed to a single motion mode of pure rotation or pure movement, lacking flexible adjustment capabilities, resulting in insufficient adaptability to robots with special drive structures.

[0006] Second, the simulation of working conditions is insufficient in terms of dynamism and coupling: the existing test platform can only simulate single motion under constant load, and cannot reproduce the dynamic load characteristics commonly found in hydraulic robot operations (such as variable load impact, instantaneous overload, and sudden load change); and it does not consider the cooperative coupling effect of multiple moving parts of the robot, and cannot simulate the force transmission law and motion coupling relationship of underactuated systems in complex scenarios such as posture adjustment and gait switching, resulting in significant deviations between the working condition simulation and the actual working scenario, making it difficult to accurately verify the performance of the hydraulic system under dynamic coupling working conditions.

[0007] Third, the verification and evaluation of nonlinear characteristics are limited in scope: existing platforms have limited means of evaluating the nonlinear characteristics of hydraulic systems (including hydraulic nonlinearity and frictional nonlinearity). They can only indirectly reflect the system control performance through single-dimensional indicators such as the accuracy of trajectory tracking in translation or rotation and the dynamic response speed. There is a lack of an evaluation system that analyzes multiple physical quantities (such as the state of moving parts and system pressure fluctuations) in a coordinated manner. This makes it impossible to comprehensively and accurately quantify the impact of nonlinear factors on the accuracy and agility of system control. As a result, it is difficult for R&D personnel to deeply understand the mechanism of nonlinear characteristics, which restricts the direction for R&D personnel to further optimize control strategies.

[0008] Therefore, there is an urgent need to develop a hydraulic drive dynamic performance verification test device that can flexibly adapt to multiple working conditions of hydraulic robots, as well as a verification and evaluation method that fully reflects the control accuracy and agility of hydraulic systems, in order to fill the existing technological gap. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a hydraulic drive dynamic performance verification test device and method to overcome the shortcomings of existing technologies, such as poor adaptability of hydraulic test platforms, unrealistic working condition simulation, and single performance evaluation dimensions.

[0010] The specific solution adopted in this invention is as follows:

[0011] On the one hand, the present invention provides a hydraulic drive dynamic performance verification test device, including a hydraulic system, an inverted pendulum hardware system, and a data acquisition and feedback system;

[0012] The hydraulic system is a closed loop, including a pump station module and a motor module. The pump station module includes a servo motor, a hydraulic pump, and two first pressure gauges. The output shaft of the servo motor is coaxially connected to the input shaft of the hydraulic pump via a coupling. The two first pressure gauges are respectively located at the two working oil ports of the hydraulic pump. The motor module includes a hydraulic motor and two other first pressure gauges. The hydraulic pump and the hydraulic motor are connected via hydraulic pipelines. The hydraulic pump outputs pressure oil to drive the hydraulic motor to rotate. The two other first pressure gauges are respectively located at the two working oil ports of the hydraulic motor.

[0013] The inverted pendulum hardware system includes an inverted pendulum body, a reducer, a limit switch, and a motion state detection encoder. The inverted pendulum body includes a slider, a pendulum rod, a belt structure, and a guide rail. The slider is slidably mounted on the guide rail. The pendulum rod is pivotally mounted on the slider via a rotating shaft and detachably connected to the slider. The output end of the hydraulic motor is connected to the slider via the belt structure to drive the slider to reciprocate along the guide rail. The motion state detection encoder includes a first encoder and a second encoder. The first encoder is used to detect the rotation angle of the pendulum rod, and the second encoder is used to detect the displacement of the slider along the guide rail. The limit switch is used to limit the movement stroke of the slider.

[0014] The data acquisition and feedback system includes a main control computer, a network-type motion control card, and a servo motor driver. The main control computer is communicatively connected to the network-type motion control card, which is also communicatively connected to the servo motor driver. The servo motor driver is electrically connected to the servo motor to achieve speed regulation. The network-type motion control card is also connected to a first pressure gauge, a first encoder, a second encoder, and a limit switch signal, respectively, for acquiring pressure signals, angle signals, displacement signals, and limit signals, and sending control commands to the servo motor driver.

[0015] The hydraulic system and the data acquisition and feedback system are both integrated and installed on the inverted pendulum body of the inverted pendulum hardware system.

[0016] Preferably, when the pendulum is removed, the test device operates in full-drive test mode, forming a pure pump-controlled hydraulic system, which is used to test the overall displacement tracking performance of the device and the accuracy of the overall model of the device;

[0017] When the pendulum is installed, the test device operates in underactuated test mode. The slider and the pendulum form a motion-coupled inverted pendulum system, which is used to test the transient agility, steady-state accuracy and overall disturbance recovery capability of the hydraulic system under underactuated balance control conditions.

[0018] The two testing modes share the same hydraulic system, data acquisition and feedback system, and driver program, and can be switched only by disassembling and assembling the swing arm.

[0019] Preferably, the pump station module further includes an accumulator, a ball valve, a second pressure gauge, two sets of check valves, and two sets of relief valves;

[0020] The oil outlet of the accumulator is connected to the two working oil ports of the hydraulic pump in sequence via a ball valve and two sets of check valves; the second pressure gauge is connected to the oil line between the accumulator and the ball valve to detect the oil source pre-pressure of the hydraulic system.

[0021] The two sets of relief valves are connected to the two working ports of the hydraulic pump in a sealed manner, which is adapted to the bidirectional rotation characteristics of the hydraulic pump and works together to limit the maximum working pressure of the hydraulic system to prevent overload. When the working pressure of the hydraulic system exceeds the set pressure of the relief valve, the oil flows back to the accumulator through the corresponding relief valve, realizing bidirectional overload protection of the hydraulic system.

[0022] Preferably, both the hydraulic pump and the hydraulic motor are provided with external vents, which are directly connected to the accumulator.

[0023] Preferably, the belt structure includes a belt and two pulleys, the two pulleys being rotatably mounted on both ends of the guide rail, the belt being tensioned and sleeved on the outside of the two pulleys and fixedly connected to the slider; a drive shaft is inserted through the center of one of the pulleys, the drive shaft being connected to a hydraulic motor via a reducer, and the slider being driven to reciprocate through the belt drive;

[0024] The top of the slider is connected to a cable chain via a connecting plate.

[0025] Preferably, the first encoder is installed at the rotation shaft of the swing arm; the second encoder is installed at the drive shaft of the pulley; a connecting member is provided between the drive shaft and the reducer, the connecting member including a reducer bracket, a transition shaft and a reducer flange, and the reducer is coaxially connected to the output end of the hydraulic motor through the connecting member.

[0026] Preferably, the servo motor driver is integrated into a servo drive debugging box, which also includes an interference filter, an AC contactor, a terminal block, a circuit breaker, and switch contacts. The circuit breaker is electrically connected to the interference filter, and the interference filter and switch contacts are electrically connected to the AC contactor. The AC contactor controls the power supply to the servo motor driver through its main contacts. The terminal block is communicatively connected to the servo motor driver for driver parameter debugging. The circuit breaker provides overload and short-circuit protection for the power supply circuit of the servo motor driver. The network motion control card is integrated into a motion control debugging box, which also includes a transformer and a switching power supply for powering the network motion control card.

[0027] Preferably, the main control computer runs a driver program developed based on the Simulink platform, which includes an initialization subroutine, a sensor acquisition subroutine, a servo motor drive subroutine, and a safety protection subroutine.

[0028] The initialization subroutine is used to load dynamic link library files, establish a communication link between the main control computer and the network motion control card, and complete the device initialization of the second pressure gauge and each encoder.

[0029] The sensor acquisition subroutine is used to acquire the pressure signal from the second pressure gauge, the angle signal from the first encoder, and the displacement signal from the second encoder in real time, and convert the acquired raw data into international standard units of measurement.

[0030] The servo motor drive subroutine receives the calculation results output by the closed-loop control algorithm designed based on the overall nonlinear model of the device, converts them into speed control commands that the servo motor can recognize, and sends them to the servo motor driver to realize the speed regulation of the servo motor.

[0031] The safety protection subroutine is used to monitor the operating status of the device and realize emergency stop, equipment power failure and communication link disconnection protection under abnormal operating conditions;

[0032] The driver program as a whole enables high-speed signal transmission and control command issuance between the main control computer and various components via Ethernet and EtherCAT bus.

[0033] On the other hand, the present invention also discloses a method for verifying the dynamic performance of hydraulic drive, which is implemented based on the above-mentioned hydraulic drive dynamic performance verification test device;

[0034] The verification method includes three stages in sequence: overall nonlinear modeling of the device, full-drive verification, and under-drive verification.

[0035] Overall nonlinear modeling of the device: Constructing an overall nonlinear model of the device that includes mechanical friction and hydraulic system characteristics;

[0036] Full-drive verification: The pendulum was removed, making the test device a pure pump-controlled hydraulic system; multiple reference displacement trajectories were preset, and a closed-loop control algorithm based on the overall nonlinear model of the device was run; the hydraulic system pressure, slider speed, acceleration, and displacement tracking error were collected in real time; the accuracy of the overall nonlinear model of the device and the overall trajectory tracking performance of the device were quantitatively verified based on the measured data.

[0037] Underactuated verification: The pendulum and slider are assembled and connected to form an inverted pendulum system with motion coupling. The pendulum start-up test, steady-state zero position test and pulse disturbance rejection test are performed in sequence to quantitatively verify the transient agility, steady-state attitude control accuracy and overall dynamic recovery capability of the device under external disturbances of the hydraulic system.

[0038] Preferably, the pendulum start-up test is performed by: driving the slider to reciprocate along the guide rail, causing the pendulum to swing from a naturally drooping state to a vertically inverted position and maintain stability; recording the hydraulic system pressure, slider acceleration, and pendulum angular acceleration; and evaluating the transient response agility of the hydraulic system under high flow conditions based on the recorded data.

[0039] The steady-state zero-position test is as follows: the pendulum is controlled to maintain within ±5° of the inverted equilibrium point using a closed-loop control algorithm; the hydraulic motor reversing pressure fluctuation and pendulum angle error are recorded; and the steady-state control accuracy of the hydraulic system in suppressing dead zone and static friction nonlinearity is evaluated based on the recorded data.

[0040] The pulse disturbance rejection test is as follows: while the pendulum is maintained within ±5° of the inverted equilibrium point, an external disturbance of a preset size is applied to the pendulum; the pendulum deflection amplitude and the time required to restore balance are recorded; and the overall dynamic recovery capability and controllability of the device are evaluated based on the recorded data.

[0041] Compared with the prior art, the present invention has at least one of the following advantages or beneficial effects:

[0042] 1. The hydraulic drive dynamic performance verification test device provided by this invention, relying on the detachable connection structure of the pendulum and slider, can quickly switch between two test scenarios: full-drive test mode and under-drive test mode, without modifying the hydraulic pipeline, electrical wiring, and driver program, making operation simple and efficient. When the pendulum is removed, the device constitutes a pure pump-controlled hydraulic system, which can be used to specifically test and verify the accuracy of the control algorithm of the pure pump-controlled hydraulic system; when the pendulum is assembled, the slider and pendulum constitute a motion-coupled inverted pendulum system, which can focus on testing and verifying the balance control parameters of the hydraulically driven robot, adapting to a wide range of scenarios. At the same time, the hydraulic system and the data acquisition and feedback system are both integrated and installed on the inverted pendulum body of the inverted pendulum hardware system, making the entire device compact and small in size, effectively solving the problems of large structure and cumbersome disassembly and assembly of existing test platforms, and can accurately adapt to the testing needs of small hydraulic robots.

[0043] 2. The hydraulic drive dynamic performance verification test device provided by the present invention accurately simulates the nonlinear working conditions faced by the hydraulic drive robot in the balance control process through an inverted pendulum structure. It can support the hydraulic system to complete complex actions such as frequent low-speed micro-motion and high-frequency reversal, fully reproduce the dynamic load characteristics and motion coupling relationship commonly seen in hydraulic robot operation, effectively solve the problem of large deviation between the working condition simulation and the actual working scenario of the existing test platform, and can accurately verify the performance of the hydraulic system under dynamic coupling conditions, fully meeting the stringent control requirements of hydraulic drive for agility and accuracy.

[0044] 3. Compared with existing hydraulic drive testing platforms, the hydraulic drive dynamic performance verification test device provided by this invention can achieve accurate testing and scientific evaluation of the balance control algorithm. By collecting multiple physical quantity data such as pressure, angle, and displacement simultaneously through the acquisition feedback system, a multi-dimensional performance evaluation system is constructed, which can clearly reflect the impact of nonlinear factors on system performance. It can comprehensively and accurately quantify the agility, accuracy, and anti-disturbance capability of the hydraulic drive system, help R&D personnel to deeply understand the mechanism of nonlinear characteristics, provide reliable data support for further optimization of hydraulic drive system control strategies, and thus provide a strong guarantee for the practical implementation and continuous development of hydraulic drive robot technology.

[0045] 4. The hydraulic drive dynamic performance verification test device provided by this invention is equipped with a triple safety protection mechanism consisting of limit switches, overflow valves, and safety protection subroutines. This effectively prevents equipment damage caused by slider overtravel, system overpressure, and misoperation, ensuring a safe and stable test process. The servo motor driver of the data acquisition and feedback system is integrated into the servo drive debugging box, and the network motion control card is integrated into the motion control debugging box. The layout is reasonable, facilitating debugging and maintenance. Furthermore, the driver program achieves signal transmission and command issuance via Ethernet and EtherCAT bus, resulting in low signal transmission delay and high stability. This ensures accurate test data and rapid control response, further improving test efficiency and reliability. Attached Figure Description

[0046] The invention, its features, shape, and advantages will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. Like reference numerals denote like parts throughout the drawings. The drawings are not drawn to scale; the emphasis is on illustrating the gist of the invention.

[0047] Figure 1 This diagram illustrates the overall components and corresponding connection relationships of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention.

[0048] Figure 2 The schematic diagram of the hydraulic closed-loop circuit of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0049] Figure 3 A top view of the inverted pendulum hardware system of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown;

[0050] Figure 4 This invention illustrates the main view of the inverted pendulum hardware system of the hydraulically driven dynamic performance verification test device in an embodiment of the present invention;

[0051] Figure 5The layout diagram of the servo drive debugging box where the servo motor driver of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0052] Figure 6 The diagram shows the layout of the motion control debugging box containing the network-type motion control card of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention.

[0053] Figure 7 The overall flowchart of the driver program for the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0054] Figure 8 The flowchart of the initialization subroutine of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0055] Figure 9 The flowchart of the sensor acquisition subroutine of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0056] Figure 10 The servo motor drive subroutine of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0057] Figure 11 The safety protection subroutine of the hydraulic drive dynamic performance verification test device in an embodiment of the present invention is shown.

[0058] Figure 12 A flowchart of the hydraulic drive dynamic performance verification method in an embodiment of the present invention is shown.

[0059] In the diagram: 1. Hydraulic system; 11. Pump station module; 111. Accumulator; 112. Ball valve; 113. Second pressure gauge; 114. First pressure gauge; 115. Servo motor; 116. Hydraulic pump; 117. Check valve; 118. Relief valve; 12. Motor module; 121. Hydraulic motor; 2. Inverted pendulum hardware system; 21. Inverted pendulum body; 211. Slider; 212. Pendulum rod; 213. Belt; 214. Guide rail; 215. Pulley; 216. Cable chain; 22. Reducer; 23. Limit switch; 24. Motion state detection encoder; 241. First encoder; 242. Second encoder; 25. Connector; 251. Reducer bracket; 252. Transition shaft; 253. Reducer flange; 3. Data acquisition and feedback system; 31. Main control computer; 32. Network motion control card; 321. Transformer; 322. Switching power supply; 33. Servo motor driver; 331. Interference filter; 332. AC contactor; 333. Terminal block; 334. Circuit breaker; 335. Switch contact. Detailed Implementation

[0060] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but these are not intended to limit the scope of the invention.

[0061] Example 1:

[0062] Reference Figure 1 This embodiment provides a hydraulic drive dynamic performance verification test device, which includes a hydraulic system 1, an inverted pendulum hardware system 2, and a data acquisition and feedback system 3. The hydraulic system 1 includes a pump station module 11 and a motor module 12. The pump station module 11 includes an accumulator 111, a ball valve 112, a first pressure gauge 114, a second pressure gauge 113, a servo motor 115, a hydraulic pump 116, two sets of check valves 117, and two sets of relief valves 118. The motor module 12 includes a hydraulic motor 121. The inverted pendulum hardware system 2 includes an inverted pendulum body 21, a reducer 22, two limit switches 23, and a motion state detection encoder 24. The motion state detection encoder 24 includes a first encoder 241 and a second encoder 242. The inverted pendulum body 21 mainly includes a slider 211 and a pendulum rod 212. The data acquisition and feedback system 3 includes a main control computer 31, a network motion control card 32, and a servo motor driver 33. The main control computer runs a driver program developed based on the Simulink platform. Hydraulic system 1 is the drive unit, inverted pendulum hardware system 2 is the execution unit, and data acquisition and feedback system 3 is the control unit.

[0063] like Figure 2As shown, the hydraulic system 1 adopts a closed-loop circuit. The return oil chamber of the hydraulic motor 121 is directly connected to the suction oil chamber of the hydraulic pump 116 through a hydraulic pipeline, resulting in a compact structure. The oil outlet of the accumulator 111 is connected to the two working oil ports of the hydraulic pump 116 via a ball valve 112 and two sets of check valves 117. The second pressure gauge 113 is connected to the oil circuit between the accumulator 111 and the ball valve 112. It is a mechanical pressure gauge used to measure the pressure of the ball valve 112, thereby obtaining the oil source pre-pressure of the hydraulic system. The oil inlet of the relief valve 118 is connected to the high-pressure working oil port of the hydraulic pump 116, and the oil outlet is connected to the low-pressure circuit to limit the maximum working pressure of the hydraulic system. The accumulator 111 is used for oil replenishment. The air bladder is pre-charged with 2 bar of pressure and isolated from the oil circuit by the ball valve 112. The two check valves 117 are used to control the selection of different oil replenishment paths for the accumulator 111. The hydraulic system 1 is equipped with four first pressure gauges 114. Two of the first pressure gauges 114 are located at the two working oil ports of the hydraulic pump 116, and the other two are located at the two working oil ports of the hydraulic motor 121. The four first pressure gauges 114 are used to measure the pressure values ​​at the inlet and outlet of the hydraulic pump 116 and the hydraulic motor 121, respectively. The communication protocol is Modbus (serial communication protocol), and the working mode is RS-485. RS-485 is a standard for multi-point communication with electrical characteristics specified by the physical layer of the OSI model, which belongs to 2-wire, half-duplex, balanced transmission line. The input shaft of the hydraulic pump 116 is coaxially connected to the output shaft of the servo motor 115 via a coupling. The hydraulic pump 116 is a fixed displacement pump, driven by the servo motor 115. The oil output from the hydraulic pump 116 directly drives the hydraulic motor 121 to rotate. The hydraulic motor 121 is a fixed displacement motor. Both the hydraulic pump 116 and the hydraulic motor 121 are provided with external vents, which are directly connected to the accumulator 111. The flow rate of the hydraulic system 1 is adjusted by changing the speed of the servo motor 115. Since the hydraulic pump 116 rotates in both directions, two sets of relief valves 118 are provided. Both sets of relief valves 118 are used to control the working pressure of the hydraulic system 1. When the working pressure of hydraulic system 1 is greater than the set pressure of relief valve 118 (for example, when slider 211 reaches the limit position of guide rail 214 and gets stuck, or when the system is overloaded), the oil will return directly to accumulator 111 through relief valve 118 to avoid system overpressure damage; accumulator 111 is used for system oil replenishment. When the system pressure is lower than the pre-charge pressure, accumulator 111 replenishes oil to the oil circuit through check valve 117 to stabilize the system pressure.

[0064] In the closed loop of hydraulic system 1, the output flow of hydraulic pump 116 is adjusted by changing the speed of servo motor 115, thereby realizing the adjustment of the output speed of hydraulic motor 121.

[0065] like Figure 3 and Figure 4The diagram shows the structure of the inverted pendulum hardware system 2 of the present invention. The inverted pendulum body 21 includes a slider 211, a pendulum rod 212, a belt 213, a guide rail 214, pulleys 215, and a drag chain 216. The slider 211 is slidably mounted on the guide rail 214. Two pulleys 215 are respectively located at both ends of the guide rail 214 and are connected by a tensioned belt 213, which is fixedly connected to the slider 211. The slider 211 can move back and forth linearly along the guide rail 214 according to the tension of the belt 213. A limit switch 23 is used to limit the movement stroke of the slider. The pendulum rod 212 is oscillatingly mounted on the slider 211 via a rotating shaft and is detachably connected to the slider 211. A first encoder 241 is installed on the rear side of the rotating shaft of the pendulum rod 212. The first encoder 241 is used to measure the rotation angle of the pendulum rod 212. The drag chain 216 is hollow and used to house cables. The drag chain 216 is made of flexible plastic. The end of the drag chain 216 near the slider 211 is fixedly connected to the slider 211 via a connecting plate, serving a guiding and protective function. When the slider 211 moves back and forth, it drives the swing arm 212 to swing back and forth, which in turn drives the drag chain 216 to move back and forth. A drive shaft runs through the center of one of the pulleys 215, driven by a hydraulic motor via a reducer. A second encoder 242 is installed at the end of this drive shaft, used to measure the displacement of the slider 211. Considering the load and speed requirements, the hydraulic motor 121 in the hydraulic system 1 cannot directly drive the inverted pendulum. Therefore, a reducer 22 and a connecting piece 25 connected to the hydraulic motor 121 are installed on the rotating shaft at the top of the pulley 215. The connecting piece 25 consists of components such as a reducer bracket 251, a transition shaft 252, and a reducer flange 253.

[0066] Specifically, the reducer 22 is fixed to the top of the inverted pendulum body 21 via the reducer bracket 251. The input end of the reducer 22 is coaxially connected to the output shaft of the hydraulic motor 121 via the reducer flange 253. The output end of the reducer 22 is fixedly connected to the transmission shaft of the pulley 215 via the transition shaft 252, thereby achieving stable power transmission.

[0067] like Figure 5As shown, the servo motor driver 33 of the data acquisition and feedback system 3 is integrated into the servo drive debugging box. The servo drive debugging box also includes an interference filter 331, an AC contactor 332, a terminal block 333, a circuit breaker 334, and a switch contact 335. The circuit breaker 334 is electrically connected to the interference filter 331. The interference filter 331 and the switch contact 335 are electrically connected to the AC contactor 332. The AC contactor 332 controls the power supply of the servo motor driver 33 through its main contacts. The terminal block is communicatively connected to the servo motor driver for driver parameter debugging. The circuit breaker 334 provides overload and short-circuit protection for the power supply circuit of the servo motor driver 33. Specifically, the power module of the servo motor driver 33 is a three-phase motor self-locking control circuit. The circuit breaker 334 provides overall protection for the power supply circuit of the servo motor 115. When the power supply circuit of the servo motor 115 is overloaded or short-circuited, the circuit breaker 334 will disconnect, cutting off the connection between the load and the power supply, thus protecting the equipment.

[0068] Interference filter 331, also known as EMI filter, is used to suppress electromagnetic interference. It can prevent noise generated inside the servo motor driver 33 from leaking outwards, and at the same time prevent noise generated by the AC line outside the servo motor driver 33 from entering the device.

[0069] The AC contactor 332 uses the magnetic field generated by the current flowing through its coil to close its contacts, thereby controlling the power supply to the servo motor driver 33. The main contacts of the AC contactor 332 are used to connect the power supply, and the switch contact 335 is used to connect the switch controlling the servo motor driver 33. The AC contactor 332 is set to a rated current of 9A and a rated voltage of 220VAC.

[0070] The servo motor driver 33 has an RS232 interface brought out through the RS232 terminal board 333 as a debugging port, which is used to modify the parameters of the servo motor driver 33 through the host computer.

[0071] like Figure 6 As shown, the network motion control card 32 is integrated into the motion control debugging box, which contains the network motion control card 32, a transformer 321 that converts 220V to 24V, and a switching power supply 322 to power the network motion control card 32. The network motion control card 32 is used to acquire the differential signals from the first encoder 241 and the second encoder 242, control the servo motor 115 via EtherCAT (real-time Ethernet), and receive control programs written by the main control computer 31 to run algorithms. Since the network motion control card 32 is powered by 24V, 220V AC power needs to be introduced from the switching power supply 322, and then the transformer 321 converts the 220V AC power to 24V DC power to power the network motion control card 32.

[0072] In the data acquisition and feedback system 3, the main control computer 31 communicates with the network-type motion control card 32. The servo motor driver 33 uses EtherCAT network port communication and communicates with the EtherCAT network port of the network-type motion control card 32 via a network cable. At the same time, the servo motor driver 33 is also connected to the servo motor 115, sending control signals to the servo motor 115 to control the speed change of the servo motor 115. The network-type motion control card 32 is also connected to the first pressure gauge 114, the second pressure gauge 113, the motion state detection encoder 24, and the limit switch 23 in the hydraulic system 1, respectively, to collect the pressure signals output by each pressure gauge and the signals output by the limit switch 23 and the motion state detection encoder 24 in the inverted pendulum hardware system 2 (i.e., to collect pressure signals, angle signals, displacement signals, and limit signals), and output control commands. The network-type motion control card 32 collects the signals output by the first encoder 241 and the second encoder 242 through two DB26 connectors and communicates with the main control computer 31 through the Ethernet network port. The main control computer runs a Simulink-based driver program. Specifically, the main control computer 31 is responsible for running the driver program, which ultimately runs in the Simulink interface of the main control computer 31. Together with the closed-loop control algorithm provided by the tester, a control closed loop is formed, and finally, control is established.

[0073] The aforementioned driver program consists of four parts: an initialization subroutine, a sensor acquisition subroutine, a servo motor drive subroutine, and a safety protection subroutine.

[0074] like Figure 1 , Figure 7 As shown, the specific working principle of the experimental device of the present invention is as follows:

[0075] The main control computer 31 in the data acquisition and feedback system 3 writes four subroutines for the network-type motion control card 32: an initialization subroutine, a sensor acquisition subroutine, a servo motor drive subroutine, and a safety protection subroutine. After the program is written, the data acquisition and feedback system is powered on. The data acquisition and feedback system 3 will first run the initialization subroutine, and then continuously loop through the sensor acquisition subroutine and the servo motor drive subroutine until the tester manually stops the operation and triggers the safety protection subroutine, or the safety protection subroutine is triggered when the slider moves to the vicinity of the limit switch, causing the system to finally stop running.

[0076] like Figure 8As shown, the initialization subroutine first loads the dynamic link library (DLL) file provided by the motion control card manufacturer, allowing subsequent servo motor drive subroutines, sensor acquisition subroutines, and safety protection subroutines to easily call their internal library functions. Next, the program calls the library function to establish a network connection, establishing a network connection between the main control computer and the motion control card. Then, the subroutine verifies whether the connection has been correctly established: on the one hand, it checks whether the main control computer has established a connection with the motion control card via a wire; on the other hand, it checks whether the IP address of the main control computer and the IP address of the motion control card are on the same network segment. If the connection is not established correctly, it prompts a connection failure and outputs an error code (issued by the relevant library function of the motion control card manufacturer), and terminates the program (meaning it directly enters the safety protection subroutine). Once the connection is successfully established, the program initializes the baud rate and serial port number of the RS-485 bus, establishes the connection with the motion control card (this connection refers to the RS-485 connection between the motion control card and all first pressure gauges), and finally initializes the serial numbers of the first and second encoders and sets the encoder pulse equivalent. The RS-485 and encoder initialization operations are all implemented using library functions provided by the motion control card manufacturer. After completing the above settings, the data acquisition and control system 3 will proceed to the next step: the sensor acquisition subroutine.

[0077] like Figure 9 As shown, the sensor acquisition subroutine first iterates through all the first pressure gauges and encoders, reading their initial values. Then, it iterates through all the limit switches, reading their data (the sensor data reading function is also implemented using library functions provided by the motion control card manufacturer), and converts the data from the first pressure gauges and the first and second encoders to standard units. This involves converting the pressure value of the first pressure gauge to Pa, the value of the first encoder to radians, and the value of the second encoder to meters (the conversion of pressure gauge and encoder values ​​is achieved simply by multiplying by a factor). After completing these steps, the subroutine outputs the converted encoder and pressure gauge data to the Simulink interface (data output to the Simulink interface is implemented using a built-in MATLAB program). The tester can use the relevant interfaces within the Simulink interface to input the system's pressure, angle, and limit information into their closed-loop control algorithm. When the slider's movement does not trigger a limit switch (when the slider moves near a limit switch and is detected by the limit switch), the program directly enters the servo motor drive subroutine; otherwise, it directly enters the safety protection subroutine.

[0078] like Figure 10As shown, when the program enters the servo motor drive subroutine, it first receives the result calculated by the closed-loop control algorithm designed by the tester. This result is then sent to the servo motor drive subroutine via Simulink (this step is implemented using MATLAB's built-in code). Using the relevant library functions provided by the motion control card manufacturer, the calculation result is first converted into a motor control command speed. This command is then sent from the main control computer, through the motion control card, to the servo driver (implemented by the motion control card's internal program). The servo driver ultimately adjusts the voltage to rotate the servo motor. After completing the above steps, if the limit switch is not triggered, the data acquisition feedback system returns to the sensor acquisition subroutine, repeating the above loop until the tester manually stops the program, entering the safety protection subroutine.

[0079] like Figure 11 As shown, after entering the safety protection subroutine, this subroutine uses the relevant library functions provided by the motion control card manufacturer to forcibly stop the servo motor's rotation. This instruction is also issued by the main control computer, passes through the motion control card to the servo driver, and the servo driver ultimately controls the servo motor's voltage to force it to stop. Afterwards, the program calls the motion control card manufacturer's library functions to forcibly disconnect the network connection between the main control computer and the motion control card.

[0080] The aforementioned hydraulic system and data acquisition and feedback system are both integrated and installed on the inverted pendulum body 21 of the inverted pendulum hardware system. When the pendulum rod 212 is removed, the test device operates in full-drive test mode, forming a pure pump-controlled hydraulic system, used to test the overall displacement tracking performance and overall model accuracy of the device. When the pendulum rod 212 is installed, the test device operates in under-drive test mode, with the slider and pendulum rod forming a motion-coupled inverted pendulum system, used to test the transient agility, steady-state accuracy, and overall disturbance rejection and recovery capability of the hydraulic system under under-drive balance control conditions. The two test modes share the same hydraulic system, data acquisition and feedback system, and driver program, and can be quickly switched by simply removing and installing the pendulum rod 212.

[0081] Example 2:

[0082] like Figure 12 As shown, this embodiment discloses a method for verifying the dynamic performance of hydraulic drive, which is based on the hydraulic drive dynamic performance verification test device disclosed in Embodiment 1 above. Specifically, the verification method includes three stages in sequence: overall nonlinear modeling of the device, full drive verification, and underdrive verification.

[0083] S1: Construction of the overall nonlinear model of the device. A nonlinear model of the device, including friction and hydraulic systems, is established, and relevant system parameters are identified. An overall mathematical model of the device is then built, laying the foundation for the verification of the control algorithm. Specifically, this involves:

[0084] S11: Friction Nonlinear Model: The main control computer continuously outputs a constant motor speed command signal through the acquisition and feedback system, causing the servo motor to drive the hydraulic motor through the hydraulic system. The slider moves at a constant speed through the reducer and pulley mechanism. At this time, the hydraulic driving force of the slider can be regarded as friction (the slider moves at a constant speed with zero acceleration). The average speed of the slider (obtained by differentiating the slider displacement measured by the second encoder) and the corresponding hydraulic driving force (obtained by multiplying the pressure difference between the first pressure gauges on both sides of the motor by the motor's displacement and then equivalently converting it through the reducer and pulley mechanism) are recorded under different constant servo motor speeds. The slider speed is plotted on the x-axis, and the equivalent friction force is plotted on the y-axis. The friction force fitting formula is obtained using the function fitting toolbox built into MATLAB software. The mean square error (MSE) and root mean square error (RMSE) are used to measure the fitting results to verify the accuracy of the designed friction polynomial fitting.

[0085] S12: Hydraulic Nonlinear Model: Constructing a high-fidelity nonlinear flow prediction model for the hydraulic pump, wherein the prediction model is a high-order flow prediction function based on the hydraulic pump speed and inlet / outlet pressure; specifically, data on the inlet / outlet pressure, outlet flow, and speed of the hydraulic pump 116 can be collected through on-site measurements. In some embodiments, S12 may include:

[0086] In step S121, the hydraulic pump 116 is connected in series with a flow sensor, and the hydraulic pump 116 is connected in parallel with a first pressure gauge 114 connected to both sides of the hydraulic pump. The hydraulic motor 121 is replaced with a manually adjustable throttle valve. By manually adjusting the opening of the throttle valve, the outlet pressure of the hydraulic pump 116 is manually adjusted. At this time, the outlet flow rate and outlet pressure of the hydraulic pump 116 can be measured by the flow sensor and the first pressure gauge 114, respectively. Multiple measurements are taken to build a large number of data points, thereby obtaining a three-dimensional mapping of pump speed, pump outlet pressure, and pump outlet flow rate.

[0087] S122: By using the data fitting toolbox of MATLAB (Matrix Labs), a custom polynomial is designed. The high-dimensional surface generated by the custom polynomial is compared with the original data. The three-dimensional mapping constructed in S1 can be fitted to construct a high-order polynomial about the hydraulic pump outlet pressure. At this time, the fitting results can be measured by the mean square error (MSE) and root mean square error (RMSE). The purpose of the measurement is to verify the accuracy of the flow prediction of the three-dimensional surface generated by the designed high-order polynomial.

[0088] S13: Construction of the overall nonlinear model of the device: The linear terms of hydraulic pump flow and friction in the traditional linear pump-controlled hydraulic system mathematical model are replaced by the model established in S11 and S12, and finally the overall nonlinear model of the device is constructed.

[0089] S2: Full-drive verification (i.e., displacement tracking test): This test treats the entire system as a purely pump-controlled hydraulic system, with the pendulum removed from the slider. The tester designs a model-based control algorithm to track the reference trajectory and verifies the accuracy of the overall nonlinear model of the device based on the displacement tracking effect, establishing a performance benchmark for subsequent coupled dynamics tests of the inverted pendulum. Specifically, this is reflected in:

[0090] S21: Reference trajectory design: Testers of the control algorithm can design the type of trajectory to be tracked through the Simulink interface, including but not limited to step, sine, ramp, and other custom reference trajectories.

[0091] S22: Embedding the Control Algorithm: After clarifying the nonlinear model of the system determined in step S1, the tester designs a model-based nonlinear control algorithm for trajectory tracking, enabling the actual displacement of the slider in the experimental setup to approximate the reference trajectory. The algorithm is deployed through the Simulink interface and integrated into the driver program mentioned in this invention, ultimately achieving displacement tracking.

[0092] S23: Data Measurement: During the displacement tracking process, the tester measures the system pressure, instantaneous velocity of the slider, acceleration, and displacement error in real time. The system pressure is measured by the first pressure gauge connected to both sides of the hydraulic pump. The displacement error of the slider is obtained by subtracting the reference trajectory from the actual displacement value measured by the second encoder during slider trajectory tracking. The instantaneous velocity and acceleration of the slider are obtained by performing first and second derivatives on the measured slider displacement by the second encoder during slider displacement tracking.

[0093] S24: Result Analysis: Based on the system pressure, instantaneous velocity and acceleration of the slider, and displacement error measured above, the control effect is analyzed. Specifically, it is reflected in:

[0094] S241: Steady-state error analysis: This refers to the difference between the actual displacement and the reference displacement after the reference trajectory stabilizes (the reference velocity or reference displacement is constant). In this embodiment, when the reference trajectory enters the steady-state stage (the desired slider velocity is 5 mm / s or the desired slider position is 60 cm), the actual displacement data is collected by a displacement sensor, and the actual velocity data is calculated by differentiation. The calculated steady-state position tracking error is ≤ ±0.02 mm, the maximum tracking error is ≤ ±0.05 mm, the velocity tracking error is ≤ 1 mm / s, the system pressure fluctuation amplitude is ≤ 0.05 MPa, and the maximum transient acceleration does not exceed 0.05 m / s². This error level indicates that the system model's error in the static parameters of the pump-controlled hydraulic system, including static friction, sliding friction coefficient, hydraulic motor flow leakage coefficient, and hydraulic pump flow leakage coefficient, is < 1%, and the error between the predicted value of the hydraulic pump flow model and the actual flow output is < 5%. The high accuracy of the model can accurately compensate for the steady-state deviation of the system, ensuring the consistency between the actual displacement and the steady-state of the reference trajectory. It can be applied to applications such as underwater precision assembly robots.

[0095] S242: Abrupt Trajectory Error Response Analysis: This refers to the peak value of the displacement tracking error when the reference trajectory experiences a step change (e.g., displacement command jumps from 5mm to 8mm) or a sudden acceleration (e.g., reference acceleration changes from 0.01m / s² to 0.03m / s²), as well as the adjustment time after entering a stable state from the start of the abrupt change. The tracking error peak value should be ≤0.12mm, the error adjustment time (converging to within ±0.03mm) ≤0.05s, with no overshoot, or an overshoot of ≤5%. By using this error adjustment time and tracking error peak value, we can measure whether the system can effectively overcome the internal nonlinear characteristics of the system (e.g., dead zone of slider movement speed, nonlinearity of friction, etc.). Furthermore, the response time can also determine whether the system's hydraulic elastic modulus parameter is accurate (the hydraulic elastic modulus determines the stiffness of the hydraulic system; the greater the stiffness, the faster the hydraulic system response).

[0096] S3: Underactuated Verification: Assemble and connect the pendulum and slider to form a motion-coupled inverted pendulum system; sequentially perform the pendulum start-up test, steady-state zero-position test, and pulse disturbance rejection test to quantitatively verify the transient agility, steady-state attitude control accuracy, and overall dynamic recovery capability of the hydraulic system under external disturbances, respectively. Specifically, this includes:

[0097] S31: Pendulum Start-up Test. This test must be performed after the pendulum is connected to the slider, specifically as follows:

[0098] S311: Implementation of the pendulum start-up function: The tester designs the pendulum start-up and stabilization programs and connects them to the driver program of this invention through the Simulink interface. First, a servo motor is driven to reciprocate (amplitude 1800 RPM, frequency approximately 0.7 Hz, similar to the natural frequency of the pendulum), driving the hydraulic system. The hydraulic motor, through a reducer and pulley mechanism, drives the slider to reciprocate. The pendulum rotates due to its connection with the slider. At this time, the network-type motion control card 32 collects the pressure information measured by the second pressure gauge 113, the pressure information measured by the first pressure gauge 114, the limit information of the limit switch 23, the angle information measured by the first encoder 241, and the displacement information of the slider 211 measured by the second encoder 242. By collecting the angle of the pendulum 212 and the displacement information of the slider 211 through the network-type motion control card 32, it is determined whether the current inverted pendulum body 21 is within the allowable dynamic balance. The judgment criteria are as follows: if the difference between the actual angle of the pendulum 212 and the expected angle of 180° (the expected angle is the angle when the pendulum 212 is parallel to the horizontal ground) is within the allowable range (±5°) and no limit switch is triggered, it proves that the pendulum start function has been realized, the pendulum start program is executed, and the pendulum stabilization program is started.

[0099] S312: Result Analysis: Record the changes in system pressure, slider transient acceleration, and pendulum transient angular acceleration from the moment the pendulum rod comes to rest until it completes its swing, and quantitatively evaluate the transient agility of the system during high-flow-rate output. Specifically, this is reflected in:

[0100] S3121: The system pressure is measured by the first pressure gauge 114. The transient acceleration of the slider is obtained by measuring the slider displacement using the second encoder and then performing a second differential. The transient angular acceleration of the pendulum is obtained by measuring the pendulum angle using the first encoder and then performing a second differential.

[0101] S3122: Quantitative Evaluation. Based on the measurement data described in S321, the core evaluation indicators are quantified as follows: the system pressure rises from its initial value to the pressure required for pendulum start (0.5MPa) in ≤0.5s, the average rise rate is ≥5MPa / s, and the deviation between the peak pressure and the pendulum start threshold is ≤0.03MPa; the peak transient acceleration of the slider is ≥0.5m / s², and the time elapsed from the start of pendulum start to the steady state of the pendulum is ≤10s; the peak transient angular acceleration of the pendulum is ≥15rad / s. If all the above indicators are met, it indicates that the system has a rapid transient response at high flow rates (≥1.1L / min), efficient conversion of hydraulic power to mechanical kinetic energy, and meets the transient agility standard. It can strongly support the rapid dynamic response control under the subsequent inverted pendulum coupling condition and can adapt to the agility requirements of practical application scenarios such as robot rapid start and rapid attitude adjustment of precision actuators.

[0102] S32: Steady-state zero-position test: This test is implemented based on S31, specifically as follows:

[0103] S321: Entering Steady State: After the pendulum initiation function is implemented, the pendulum stabilization program designed by the tester will continuously receive the system pressure, first and second encoder values ​​sent by the sensor acquisition subroutine in the driver program, and maintain the inverted pendulum system in a steady state through the tester's balance control algorithm: When the absolute value of the difference between the swing angle of the pendulum 212 and the angle perpendicular to the horizontal ground (180°) is less than or equal to 5 degrees, the pendulum stabilization program will continuously output control commands. When this difference is positive, the program outputs a signal for the servo motor 115 to rotate in the opposite direction, causing the slider 211 to move closer to the second encoder 242, thus reducing the displacement data measured by the second encoder 242; the opposite is also true.

[0104] S322: Near the inverted equilibrium point, record the pressure jump of the hydraulic motor during reversal and the actual angle error of the pendulum rod to quantitatively evaluate the system's accuracy switching from pendulum initiation to stabilization, as well as the system's accuracy in overcoming dead zones and static friction during stabilization. Specifically, this is reflected in:

[0105] S3221: Controllability Assessment. After the inverted pendulum enters a stable pendulum state, based on the hydraulic motor reversing pressure data collected by the first pressure gauge and the pendulum angle and slider displacement data measured by the first and second encoders, the amplitude of the pressure change during motor reversal is ≤0.5MPa through targeted compensation and adjustment of the control algorithm designed by the tester. The system pressure fluctuates within ±0.1MPa after the inverted pendulum enters a stable pendulum state; the instantaneous error between the actual pendulum angle and the inverted equilibrium point (180°) is ≤±0.4°, and the angle error is stable within the allowable range of ±0.2° for 100 consecutive sampling periods, with no cumulative offset or attitude drift (the pendulum angle can be continuously stable within the allowable range). When the above indicators are met, it indicates that the system can effectively suppress the interference caused by dead zone and static friction under steady-state zero-position conditions, accurately control the fluctuation of hydraulic power output and pendulum attitude deviation, achieve steady-state controllability, ensure that the inverted pendulum continuously and stably maintains dynamic balance, and is suitable for application scenarios such as long-term steady-state attitude control of precision actuators.

[0106] S33: Impulse Immunity Test: This test is based on S32 and specifically includes:

[0107] S331: Manually apply external disturbance. In steady state, manually apply an external disturbance, record the pendulum deflection amplitude and the time required to restore balance, and evaluate the system's dynamic recovery capability and controllability under external shocks in steady state. Specifically, this is reflected in:

[0108] S332: Pulse Disturbance Controllability Assessment: After the inverted pendulum maintains a stable state, a pulsed external disturbance is manually applied to the middle of the pendulum rod (disturbance force range approximately 5N, duration ≤0.5s, ensuring the disturbance is an instantaneous impact and does not damage the mechanical structure). The pendulum rod angle change is recorded in real time using the first encoder, and the slider position change is recorded in real time using the second encoder. Hydraulic system pressure response data from the first pressure gauge is collected synchronously. The maximum deflection amplitude of the pendulum rod after disturbance is ≤±1.5° (relative to the inverted equilibrium point 180°), and the allowed time for the pendulum rod to recover equilibrium is ≤0.1s; the hydraulic system pressure fluctuation amplitude during recovery is ≤0.4MPa, and the pressure can quickly return to the steady-state range (±0.1MPa fluctuation) within 0.5s. When the above indicators are met, it indicates that when the system encounters external shocks and disturbances in a steady state, the control algorithm can quickly trigger compensation commands, offset the impact of disturbances by precisely adjusting the hydraulic power output, effectively suppress the pendulum attitude drift, and achieve rapid dynamic recovery response without runaway oscillations. The steady-state anti-disturbance controllability meets the standards, meeting the core requirements of robot mechanisms in practical applications to resist sudden disturbances and maintain a steady-state attitude. This is especially important when the robot enters different types of terrain, where changes in angle due to terrain changes may lead to tipping problems.

[0109] Those skilled in the art should understand that variations can be implemented by combining existing technology with the above embodiments. Such variations do not affect the essence of the present invention and will not be elaborated upon here.

[0110] The preferred embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A hydraulic drive dynamic performance verification test device, characterized in that, This includes a hydraulic system, an inverted pendulum hardware system, and a data acquisition and feedback system. The hydraulic system is a closed loop, including a pump station module and a motor module. The pump station module includes a servo motor, a hydraulic pump, and two first pressure gauges. The output shaft of the servo motor is coaxially connected to the input shaft of the hydraulic pump via a coupling. The two first pressure gauges are respectively located at the two working oil ports of the hydraulic pump. The motor module includes a hydraulic motor and two other first pressure gauges. The hydraulic pump and the hydraulic motor are connected via hydraulic pipelines. The hydraulic pump outputs pressure oil to drive the hydraulic motor to rotate. The two other first pressure gauges are respectively located at the two working oil ports of the hydraulic motor. The inverted pendulum hardware system includes an inverted pendulum body, a reducer, a limit switch, and a motion state detection encoder. The inverted pendulum body includes a slider, a pendulum rod, a belt structure, and a guide rail. The slider is slidably mounted on the guide rail. The pendulum rod is pivotally mounted on the slider via a rotating shaft and detachably connected to the slider. The output end of the hydraulic motor is connected to the slider via the belt structure to drive the slider to reciprocate along the guide rail. The motion state detection encoder includes a first encoder and a second encoder. The first encoder is used to detect the rotation angle of the pendulum rod, and the second encoder is used to detect the displacement of the slider along the guide rail. The limit switch is used to limit the movement stroke of the slider. The data acquisition and feedback system includes a main control computer, a network-type motion control card, and a servo motor driver. The main control computer is communicatively connected to the network-type motion control card, which is also communicatively connected to the servo motor driver. The servo motor driver is electrically connected to the servo motor to achieve speed regulation. The network-type motion control card is also connected to a first pressure gauge, a first encoder, a second encoder, and a limit switch signal, respectively, for acquiring pressure signals, angle signals, displacement signals, and limit signals, and sending control commands to the servo motor driver. The hydraulic system and the data acquisition and feedback system are both integrated and installed on the inverted pendulum body of the inverted pendulum hardware system.

2. The hydraulic drive dynamic performance verification test device according to claim 1, characterized in that, When the pendulum is removed, the test device operates in full-drive test mode, forming a pure pump-controlled hydraulic system, which is used to test the overall displacement tracking performance of the device and the accuracy of the overall model of the device. When the pendulum is installed, the test device operates in underactuated test mode. The slider and the pendulum form a motion-coupled inverted pendulum system, which is used to test the transient agility, steady-state accuracy and overall disturbance recovery capability of the hydraulic system under underactuated balance control conditions. The two testing modes share the same hydraulic system, data acquisition and feedback system, and driver program, and can be switched only by disassembling and assembling the swing arm.

3. The hydraulic drive dynamic performance verification test device according to claim 1, characterized in that, The pump station module also includes an accumulator, a ball valve, a second pressure gauge, two sets of check valves, and two sets of relief valves; The oil outlet of the accumulator is connected to the two working oil ports of the hydraulic pump in sequence via a ball valve and two sets of check valves; the second pressure gauge is connected to the oil line between the accumulator and the ball valve to detect the oil source pre-pressure of the hydraulic system. The two sets of relief valves are connected to the two working ports of the hydraulic pump in a sealed manner, which is adapted to the bidirectional rotation characteristics of the hydraulic pump and works together to limit the maximum working pressure of the hydraulic system to prevent overload. When the working pressure of the hydraulic system exceeds the set pressure of the relief valve, the oil flows back to the accumulator through the corresponding relief valve, realizing bidirectional overload protection of the hydraulic system.

4. The hydraulic drive dynamic performance verification test device according to claim 1, characterized in that, Both the hydraulic pump and the hydraulic motor are provided with external vents, which are directly connected to the accumulator.

5. The hydraulic drive dynamic performance verification test device according to claim 1, characterized in that, The belt structure includes a belt and two pulleys. The two pulleys are rotatably mounted on both ends of the guide rail. The belt is in a tensioned state and is sleeved on the outside of the two pulleys and fixedly connected to the slider. A drive shaft is inserted through the center of one of the pulleys. The drive shaft is connected to a hydraulic motor via a reducer and drives the slider to reciprocate through the belt drive. The top of the slider is connected to a cable chain via a connecting plate.

6. The hydraulic drive dynamic performance verification test device according to claim 5, characterized in that, The first encoder is installed on the rotating shaft of the swing arm; the second encoder is installed on the drive shaft of the pulley; a connecting member is provided between the drive shaft and the reducer, the connecting member includes a reducer bracket, a transition shaft and a reducer flange, and the reducer is coaxially connected to the output end of the hydraulic motor through the connecting member.

7. The hydraulic drive dynamic performance verification test device according to claim 1, characterized in that, The servo motor driver is integrated into a servo drive debugging box, which also includes an interference filter, an AC contactor, a terminal block, a circuit breaker, and switch contacts. The circuit breaker is electrically connected to the interference filter, and the interference filter and switch contacts are electrically connected to the AC contactor. The AC contactor controls the power supply to the servo motor driver through its main contacts. The terminal block is communicatively connected to the servo motor driver for driver parameter debugging. The circuit breaker provides overload and short-circuit protection for the power supply circuit of the servo motor driver. The network motion control card is integrated into a motion control debugging box, which also includes a transformer and a switching power supply for powering the network motion control card.

8. The hydraulic drive dynamic performance verification test device according to claim 1, characterized in that, The main control computer runs a driver program developed based on the Simulink platform. The driver program includes an initialization subroutine, a sensor acquisition subroutine, a servo motor drive subroutine, and a safety protection subroutine. The initialization subroutine is used to load dynamic link library files, establish a communication link between the main control computer and the network motion control card, and complete the device initialization of the second pressure gauge and each encoder. The sensor acquisition subroutine is used to acquire the pressure signal from the second pressure gauge, the angle signal from the first encoder, and the displacement signal from the second encoder in real time, and convert the acquired raw data into international standard units of measurement. The servo motor drive subroutine receives the calculation results output by the closed-loop control algorithm designed based on the overall nonlinear model of the device, converts them into speed control commands that the servo motor can recognize, and sends them to the servo motor driver to realize the speed regulation of the servo motor. The safety protection subroutine is used to monitor the operating status of the device and realize emergency stop, equipment power failure and communication link disconnection protection under abnormal operating conditions; The driver program as a whole enables high-speed signal transmission and control command issuance between the main control computer and various components via Ethernet and EtherCAT bus.

9. A method for verifying the dynamic performance of a hydraulic drive, characterized in that, This is achieved based on the hydraulic drive dynamic performance verification test device according to any one of claims 1 to 8; The verification method includes three stages in sequence: overall nonlinear modeling of the device, full-drive verification, and under-drive verification. Overall nonlinear modeling of the device: Constructing an overall nonlinear model of the device that includes mechanical friction and hydraulic system characteristics; Full-drive verification: Remove the pendulum rod to make the test device a pure pump-controlled hydraulic system; Multiple reference displacement trajectories are preset, and a closed-loop control algorithm based on the overall nonlinear model of the device is run; the hydraulic system pressure, slider speed, acceleration, and displacement tracking error are collected in real time; the accuracy of the overall nonlinear model of the device and the overall trajectory tracking performance of the device are quantitatively verified based on the measured data. Underactuated verification: The pendulum and slider are assembled and connected to form an inverted pendulum system with motion coupling. The pendulum start-up test, steady-state zero position test and pulse disturbance rejection test are performed in sequence to quantitatively verify the transient agility, steady-state attitude control accuracy and overall dynamic recovery capability of the device under external disturbances of the hydraulic system.

10. The method for verifying the dynamic performance of hydraulic drive according to claim 9, characterized in that, The pendulum test is as follows: drive the slider to reciprocate along the guide rail, so that the pendulum rod swings from a naturally drooping state to a vertical inverted position and remains stable; record the hydraulic system pressure, slider acceleration and pendulum rod angular acceleration; evaluate the transient response agility of the hydraulic system under high flow conditions based on the recorded data; The steady-state zero-position test is as follows: the pendulum is controlled to maintain within ±5° of the inverted equilibrium point using a closed-loop control algorithm; the hydraulic motor reversing pressure fluctuation and pendulum angle error are recorded; and the steady-state control accuracy of the hydraulic system in suppressing dead zone and static friction nonlinearity is evaluated based on the recorded data. The pulse disturbance rejection test is as follows: while the pendulum is maintained within ±5° of the inverted equilibrium point, an external disturbance of a preset size is applied to the pendulum; the pendulum deflection amplitude and the time required to restore balance are recorded; and the overall dynamic recovery capability and controllability of the device are evaluated based on the recorded data.

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