Lunar rover motion system and electromechanical hydraulic control simulation platform construction method

Abstract

The present invention belongs to the field of space exploration technology, and specifically relates to a cargo-carrying lunar rover motion system, which includes a front drive assembly, a cargo cabin, a posture sensor and a main drive assembly. The main drive assembly includes a main support rod, a rocker arm, a main wheel, a second force sensor, a main hydraulic cylinder, a second servo valve and a second displacement sensor. The cargo cabin relies on the drive assembly to achieve tilt. The present invention also discloses a method for building an electromechanical and hydraulic control simulation platform for the cargo-carrying lunar rover motion system, including a kinematic module that calculates the expected displacement of the servo valve-controlled cylinder based on the expected tilt angle of the cargo cabin; obtains the actual displacement of the servo valve-controlled cylinder through the servo valve-controlled cylinder position control module; establishes a multi-body dynamics module, establishes the system's electromechanical and hydraulic control simulation platform based on the module and signal flow relationship, and verifies the accuracy of the simulation. The present invention can achieve stable operation of the cargo cabin on the rugged road surface of the lunar surface, and the simulation platform construction method is helpful for the design, testing and optimization of the equipment.

Description

Technical Field

[0001] The present invention belongs to the field of space exploration technology, and in particular relates to a motion system of a cargo-carrying lunar rover and a method for building an electromechanical-hydraulic control simulation platform thereof. Background Art

[0002] With the advancement of global space technology, humanity's exploration of the Moon and other planets has deepened. Planetary exploration technology has rapidly advanced, and planetary rovers have become indispensable equipment for planetary exploration. However, current lunar rovers face numerous challenges in the lunar surface environment, including various obstacles, complex surface conditions, and diverse mission scenarios. Therefore, many technical issues remain to be addressed and overcome in this field.

[0003] For example, in the uneven, loose lunar soil environment, the bumpy ride of the rover could cause the cargo in its payload compartment to sway or loosen, thus affecting the successful completion of the exploration and collection mission. This places higher demands on the rover's balance and safety, requiring further optimization and improvement in design and technology to ensure the smooth operation of the rover's payload compartment in this rugged environment.

[0004] At the same time, given the complex engineering requirements of aerospace equipment and the lengthy testing and experimentation cycles associated with manufacturing physical equipment, virtual simulation technology offers a new solution. Virtual simulation systems, combining computer and graphics processing technologies, provide a more efficient approach for designing and optimizing the motion system of a lunar rover. Through simulation, performance testing and optimization of the rover's motion system can be performed under various operating conditions, leading to a more comprehensive design solution. This approach significantly improves the efficiency of the design process, garnering widespread attention from scholars and being applied in research across various fields.

[0005] Based on the above background, it is very necessary and urgent to establish a method for building a simulation platform for the motion system of a lunar rover and its electromechanical and hydraulic control, which will provide important support for further research in this field. Summary of the Invention

[0006] In response to the above situation, the present invention provides a method for building a manned lunar rover motion system and an electromechanical-hydraulic control simulation platform thereof, which overcomes the shortcomings of the existing technology. Through the coordinated control between different drive components, the manned lunar rover motion system can achieve precise control of the angle of the cargo cabin and smooth operation on the complex lunar surface, ensure the smooth completion of the work mission, and improve the stability of the system. Combined with virtual simulation technology, it can not only simulate the lunar environment, but also perform performance testing and structural optimization on the existing manned lunar rover motion system, thereby improving the efficiency of the design and research of the manned lunar rover motion system.

[0007] The technical solution adopted by the present invention is to provide a cargo lunar rover motion system, including a front drive assembly, a cargo cabin, a posture sensor and a main drive assembly. The front drive assembly is arranged at the first end of the cargo cabin, the main drive assembly is arranged at the second end of the cargo cabin, the posture sensor is arranged on the second end surface of the cargo cabin, and the posture sensor is located between the front drive assembly and the main drive assembly. The front drive assembly includes a first cargo compartment connecting plate, a front support rod, a front wheel, a second cargo compartment connecting plate, a first force sensor, a front hydraulic cylinder, a first servo valve, a front piston rod and a first displacement sensor. The first cargo compartment connecting plate is hinged at the first end of the front support rod and is installed at the first end of the cargo compartment by screws. The second end of the front support rod is installed with the front wheel, and a rotation pair is formed between the front wheel and the front support rod. The first end of the front hydraulic cylinder is hinged to the second cargo compartment connecting plate and is installed on the cabin body of the cargo compartment through the second cargo compartment connecting plate. The first end of the front hydraulic cylinder is installed with the first force sensor, the first side of the central position is installed with the first servo valve, and the second side is installed with the first displacement sensor. The front piston rod is installed in the cylinder body of the front hydraulic cylinder, and the second end is connected to the midpoint of the front support rod through a hinged seat, and the front piston rod and the front hydraulic cylinder form a moving pair.

[0008] The main drive assembly includes a main support rod, a rocker arm, a main wheel, a second force sensor, a main hydraulic cylinder, a second servo valve, a main piston rod and a second displacement sensor. The first end of the main support rod is fixedly mounted on the cabin body of the cargo compartment by bolts, and the second end is hinged to the first end of the rocker arm by a hinge. The first end of the main support rod is fixedly provided with a cantilever, and the first end of the main hydraulic cylinder is hinged to the second end of the cantilever by a hinge. The first end of the main hydraulic cylinder is installed with a second force sensor, the first side of the central position is installed with a second servo valve, and the second side is installed with a second displacement sensor. The main piston rod is installed in the cylinder body of the main hydraulic cylinder, and a moving pair is formed between the main hydraulic cylinder and the main piston rod, the second end of the rocker arm is installed with a main wheel, and a rotating pair is formed between the rocker arm and the main wheel, and the second end of the main piston rod is hinged to the second end of the rocker arm to form a rotating pair.

[0009] Preferably, the main wheel of the main drive assembly is installed toward the second end of the cargo compartment.

[0010] Preferably, there are four main drive assemblies in total, and they are symmetrically distributed on both sides of the first symmetry plane of the cargo compartment.

[0011] A second aspect of the present invention provides a method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system, comprising the following steps:

[0012] S1: Based on the mechanical structure and expected tilt angle of the lunar rover motion system, the kinematic equations of the lunar rover motion system are established, and the displacement of the servo valve-controlled cylinders of the front drive assembly and the four main drive assemblies of the lunar rover motion system are planned to obtain the expected displacement of the servo valve-controlled cylinders. This includes the following sub-steps:

[0013] S11: Based on the mechanical structure of the lunar rover motion system, establish the kinematic model of the front drive components of the lunar rover motion system.

[0014]

[0015] Where Xr0 represents the extension of the hydraulic cylinder of the front drive assembly, CD represents the distance between points C and D, DE represents the distance between points D and E, BD represents the distance between points B and D, DF represents the distance between points D and F, p represents the distance between points B and F, ∠FDE represents the angle between points FD and ED, l 00 Indicates the distance between point C and point E at the initial position;

[0016] S12: Based on the mechanical structure of the lunar rover motion system, establish the kinematic model of the main drive components of the lunar rover motion system.

[0017]

[0018] Where Xr3 represents the extension of the hydraulic cylinder of the rear main drive assembly, GH represents the distance between points G and H, HI represents the distance between points H and I, HK represents the distance between points H and K, d represents the distance between points G and K, ∠IHK represents the angle between points IH and KH, l 03 Indicates the distance between point G and point I at the initial position;

[0019] S2: The expected displacement of the servo valve-controlled cylinder of the front drive assembly and the four main drive assemblies and the force sensor signal collected by the multi-body dynamics model are used as input to obtain the actual displacement of the servo valve-controlled cylinder through the servo valve-controlled cylinder position control module;

[0020] S3: Draw a 3D model of the lunar rover motion system and use the multi-body dynamics tool library in the simulation software to build a multi-body dynamics module for the lunar rover motion system.

[0021] S4: Build a mechatronic hydraulic control simulation platform for the lunar rover motion system by integrating the kinematics module, servo valve-controlled cylinder position control module, and multi-body dynamics module, as well as the flow of control and sensor signals between these modules.

[0022] S5: Verify the accuracy of the simulation results of the servo valve-controlled cylinder displacement and the cargo cabin angle of the electromechanical-hydraulic control simulation platform of the cargo lunar rover motion system.

[0023] Preferably, step S2 specifically includes the following sub-steps:

[0024] S21: By analyzing the structure and control principle of the servo valve control cylinder, the state variables are selected as x1=x p , x3=p L , we get the state space equation of the servo valve controlled cylinder system,

[0025]

[0026] in, x1, x2, x3 are the three state variables of the state space equation of the servo valve control cylinder system. Represents the first-order derivative of x1, x2, x3 with respect to time, x p Indicates the displacement of the servo valve control cylinder piston, Represents x p The first derivative with respect to time, p L Indicates the load pressure of the servo valve control cylinder, K indicates the load stiffness, B p Represents the viscous damping coefficient of the load and servo valve control cylinder, m t Indicates the total mass converted to the servo valve control cylinder piston, A1 represents the area of ​​the rodless cavity of the asymmetric hydraulic cylinder, n represents the ratio of the area of ​​the rod cavity to the rodless cavity of the asymmetric hydraulic cylinder, C ip Indicates the leakage coefficient of the hydraulic cylinder, C ep Indicates the external leakage coefficient of the hydraulic cylinder, k d Indicates the reduced flow coefficient, k PID Indicates PID gain, k axv Indicates the servo valve gain, P s Indicates the oil supply pressure, V indicates the total volume of the chamber, β e Represents the viscous damping coefficient of the load and the servo valve control cylinder, u1 and u2 represent two input variables, where u1 = x r , u2=F L , x r Indicates the expected displacement of the servo valve controlled cylinder, F L represents the load force of the servo valve controlled cylinder, and y represents the system output variable;

[0027] S22: According to the formula, build a servo valve-controlled cylinder position control module in the simulation software.

[0028] Preferably, step S3 specifically includes the following sub-steps:

[0029] S31: Draw the 3D model of each part and component of the lunar rover motion system in the 3D design software, and set the properties of each part and component;

[0030] S32: In 3D design software, apply fit constraints between parts and components based on the actual motion and connection relationships between them;

[0031] S33: Use 3D design software to export the lunar rover motion system assembly file into XML and STL files;

[0032] S34: Read the corresponding xml file and stl file in the simulation software to build the multi-body dynamics module of the lunar rover motion system.

[0033] Preferably, step S4 specifically includes the following sub-steps:

[0034] S41: According to the world coordinate system and the actual needs of the electromechanical-hydraulic control simulation platform of the lunar rover motion system, set the basic parameters including gravity acceleration;

[0035] S42: In the multi-body dynamics module, according to the actual relationship between the lunar rover motion system and the ground, a corresponding contact force module is added. The wheels of the lunar rover motion system are brought into contact with the ground through the first coordinate transformation module Transform1, and basic contact model parameters including stiffness, damping, and friction coefficient are set.

[0036] S43: Control signal X p Input to the multi-body dynamics module, measure the sensor signal Force, and input Force as the load force of the servo valve-controlled cylinder to the servo valve-controlled cylinder position control module;

[0037] S44: The cylinder structure and piston structure of the servo valve control cylinder are connected through a moving pair, which drives the input signal X of the component. p As input, the position sensor signal P, velocity sensor signal V and force sensor signal F of the moving pair are used. p As output, it completes the real-time control and monitoring of the servo valve control cylinder of the drive component, and converts the force sensing signal F p As the load force input to the hydraulic system, it completes the closed-loop control of the servo valve control cylinder of the drive component and completes the construction of the electromechanical and hydraulic control simulation platform for the lunar rover motion system;

[0038] S45: An electromechanical and hydraulic control simulation platform for the lunar rover's motion system.

[0039] Preferably, step S5 specifically includes the following sub-steps:

[0040] S51: verifying the expected displacement of the servo valve-controlled cylinder obtained by theoretical calculation, the actual displacement of the servo valve-controlled cylinder obtained by the servo valve-controlled cylinder position control module, and the simulated displacement measured by the electromechanical-hydraulic control simulation platform;

[0041] S52: Compare and verify the expected angle of the payload cabin of the lunar rover motion system and the simulated measurement angle results.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] 1. The present invention achieves precise tilt motion control of the lunar rover's cargo cabin through coordinated control of the front drive assembly and the main drive assembly, thereby ensuring the cabin's levelness on the rugged lunar surface and ensuring the stability and safety of the cargo and equipment inside the cabin.

[0044] 2. This invention conducts modular modeling and simulation of the kinematics module, servo valve-controlled cylinder position control module, and multi-body dynamics module of the lunar rover motion system. This method not only verifies the control theory of the lunar rover motion system but also simplifies the design, testing, and optimization process of the lunar rover motion system, thereby reducing the R&D cycle.

[0045] 3. Compared with traditional mechanical design methods, the proposed method can better study and analyze the working status and performance of the lunar rover's motion system, simulate the motion conditions under different working conditions, and comprehensively evaluate its performance, thus avoiding the need for multiple trial and error production of prototypes. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a structural schematic diagram of the present invention;

[0047] Figure 2a This is a front view of the front drive assembly structure diagram of the present invention;

[0048] Figure 2b This is a left side view of the front drive assembly structure schematic diagram of the present invention;

[0049] Figure 3a This is a front view of the main drive assembly structure diagram of the present invention;

[0050] Figure 3b It is a left view of the main drive assembly structure schematic diagram of the present invention;

[0051] Figure 4 This is a flow chart of the method for building an electromechanical and hydraulic control simulation platform of the present invention;

[0052] Figure 5 This is a schematic diagram of the electromechanical and hydraulic control simulation platform and the signal flow of each module of the present invention;

[0053] Figure 6 A flow chart for establishing a kinematic model for the lunar rover motion system of the present invention;

[0054] Figure 7 Schematic diagram of the geometric relationship of the lunar rover motion system of the present invention;

[0055] Figure 8 Build a flow chart of the servo valve-controlled cylinder position control module for the electromechanical-hydraulic control simulation platform of the present invention;

[0056] Figure 9 Schematic diagram of the servo valve controlled cylinder position control module of the present invention;

[0057] Figure 10 Build a multi-body dynamics module flow chart for the electromechanical and hydraulic control simulation platform of the present invention;

[0058] Figure 11 A flow chart for constructing a simulation platform for each module of the electromechanical-hydraulic control simulation platform of the present invention;

[0059] Figure 12 Schematic diagram of the multi-body dynamics module of the present invention;

[0060] Figure 13 This is a schematic diagram of the servo valve-controlled cylinder multi-body dynamics module of the present invention;

[0061] Figure 14a A schematic diagram of a first-person perspective image of the operating state of the electromechanical-hydraulic control simulation platform of the present invention;

[0062] Figure 14b A schematic diagram of a third-perspective image of the operating state of the electromechanical-hydraulic control simulation platform of the present invention;

[0063] Figure 15 This is a flow chart for verifying simulation results of the electromechanical-hydraulic control simulation platform of the present invention;

[0064] Figure 16 This is a curve diagram for simulating and verifying the displacement of the servo valve-controlled cylinder according to the present invention;

[0065] Figure 17 This is an angle simulation verification curve diagram of the present invention. DETAILED DESCRIPTION

[0066] To fully describe the technical content, structural features, objectives and effects of the present invention, the following is a detailed description with reference to the accompanying drawings.

[0067] The present invention provides a lunar rover motion system. Figure 1 , Figure 2a-2b , Figure 3a-3bAs shown, it includes a front drive component 1, a cargo compartment 2, a posture sensor 3 and a main drive component 4. The front drive component 1 is arranged at the first end of the cargo compartment 2. There are four main drive components 4, which are arranged at the second end of the cargo compartment 2 and are symmetrically distributed on both sides of the first symmetry plane of the cargo compartment 2. The posture sensor 3 is arranged on the second end surface of the cargo compartment 2, between the front drive component 1 and the main drive component 4. The front drive assembly 1 includes a first cargo compartment connecting plate 5, a front support rod 6, a front wheel 7, a second cargo compartment connecting plate 8, a first force sensor 9, a front hydraulic cylinder 10, a first servo valve 11, a front piston rod 12 and a first displacement sensor 13. The first cargo compartment connecting plate 5 is hinged at the first end of the front support rod 6 and is installed at the first end of the cargo compartment 2 by screws. The second end of the front support rod 6 is installed with the front wheel 7, and a rotation pair is formed between the front wheel 7 and the front support rod 6. The first end of the front hydraulic cylinder 10 is hinged to the second cargo compartment connecting plate 8 and is installed on the cabin body of the cargo compartment 2 through the second cargo compartment connecting plate 8. The first end of the front hydraulic cylinder 10 is installed with the first force sensor 9, the first servo valve 11 is installed on the first side of the central position, and the first displacement sensor 13 is installed on the second side. The front piston rod 12 is installed in the cylinder body of the front hydraulic cylinder 10, and the second end is connected to the midpoint of the front support rod 6 through a hinge seat, and the front piston rod 12 and the front hydraulic cylinder 10 form a moving pair.

[0068] The main drive assembly 4 includes a main support rod 14, a rocker arm 15, a main wheel 16, a second force sensor 17, a main hydraulic cylinder 18, a second servo valve 19, a main piston rod 20 and a second displacement sensor 21. The first end of the main support rod 14 is fixedly mounted on the body of the cargo compartment 2 by bolts, and the second end is hinged to the first end of the rocker arm 15 by a hinge. The first end of the main support rod 14 is fixedly provided with a cantilever 22, the first end of the main hydraulic cylinder 18 is hinged to the second end of the cantilever 22 by a hinge, and the first end of the main hydraulic cylinder 18 is installed with a second force sensor 17. Sensor 17, a second servo valve 19 is installed on the first side of the central position, and a second displacement sensor 21 is installed on the second side. A main piston rod 20 is installed in the cylinder body of the main hydraulic cylinder 18, and a moving pair is formed between the main hydraulic cylinder 18 and the main piston rod 20. The second end of the rocker arm 15 is installed with a main wheel 16, and a rotating pair is formed between the rocker arm 15 and the main wheel 16. The second end of the main piston rod 20 is hinged to the second end of the rocker arm 15 to form a rotating pair. In addition, the main wheel 16 of the main drive assembly 4 is installed toward the second end of the cargo compartment 2.

[0069] The second aspect of the present invention provides a method for constructing an electromechanical and hydraulic control platform for a lunar rover motion system. Figures 4 to 7 As shown, the following steps are included:

[0070] S1: Based on the mechanical structure and expected tilt angle of the lunar rover motion system, the kinematic equation of the lunar rover motion system is established, and the displacement of the servo valve-controlled cylinder of the front drive component 1 and the four main drive components 4 of the lunar rover motion system is planned to obtain the expected displacement of the servo valve-controlled cylinder. The process includes the following sub-steps:

[0071] S11: Based on the mechanical structure of the lunar rover motion system, establish the kinematic model of the front drive component 1 of the lunar rover motion system.

[0072]

[0073] Where Xr0 represents the extension of the hydraulic cylinder of the front drive assembly 1, CD represents the distance between points C and D, DE represents the distance between points D and E, BD represents the distance between points B and D, DF represents the distance between points D and F, p represents the distance between points B and F, ∠FDE represents the angle between points FD and ED, l 00 Indicates the distance between point C and point E at the initial position;

[0074] S12: Based on the mechanical structure of the lunar rover motion system, establish the kinematic model of the four hydraulic cylinders of the main drive assembly of the lunar rover motion system.

[0075]

[0076] Wherein, Xr3 represents the extension of the hydraulic cylinder of the rear main drive assembly 4, GH represents the distance between point G and point H, HI represents the distance between point H and point I, HK represents the distance between point H and point K, d represents the distance between point G and point K, ∠IHK represents the angle between points IH and KH, l 03 Indicates the distance between point G and point I at the initial position;

[0077] S2: The expected displacement of the servo valve-controlled cylinder of the front drive component 1 and the four main drive components 4 and the force sensing signal collected by the multi-body dynamics model are used as input to obtain the actual displacement of the servo valve-controlled cylinder through the servo valve-controlled cylinder position control module;

[0078] S3: Draw a 3D model of the lunar rover motion system and use the multi-body dynamics tool library in the simulation software to build a multi-body dynamics module for the lunar rover motion system.

[0079] S4: Build an electromechanical and hydraulic simulation platform for the lunar rover motion system by integrating the kinematics module, servo valve-controlled cylinder position control module, and multi-body dynamics module, as well as the flow of control and sensor signals between these modules.

[0080] S5: Verify the accuracy of the simulation results of the servo valve-controlled cylinder displacement and the angle of the cargo cabin 2 of the electromechanical-hydraulic control simulation platform of the cargo lunar rover motion system.

[0081] like Figure 8 and Figure 9 As shown, step S2 specifically includes the following sub-steps:

[0082] S21: By analyzing the structure and control principle of the servo valve control cylinder, the state variables are selected as x1=x p , x3=p L , we get the state space equation of the servo valve controlled cylinder system,

[0083]

[0084] in, x1, x2, x3 are the three state variables of the state space equation of the servo valve control cylinder system. Represents the first-order derivative of x1, x2, x3 with respect to time, x p Indicates the displacement of the servo valve control cylinder piston, Represents x p The first derivative with respect to time, p L Indicates the load pressure of the servo valve control cylinder, K indicates the load stiffness, B p Represents the viscous damping coefficient of the load and servo valve control cylinder, m t Indicates the total mass converted to the servo valve control cylinder piston, A1 represents the area of ​​the rodless cavity of the asymmetric hydraulic cylinder, n represents the ratio of the area of ​​the rod cavity to the rodless cavity of the asymmetric hydraulic cylinder, C ip Indicates the leakage coefficient of the hydraulic cylinder, C ep Indicates the external leakage coefficient of the hydraulic cylinder, k d Indicates the reduced flow coefficient, k PID Indicates PID gain, k axv Indicates the servo valve gain, P s Indicates the oil supply pressure, V indicates the total volume of the chamber, β e Represents the viscous damping coefficient of the load and the servo valve control cylinder, u1 and u2 represent two input variables, where u1 = x r , u2=F L , x r Indicates the expected displacement of the servo valve controlled cylinder, F L represents the load force of the servo valve controlled cylinder, and y represents the system output variable;

[0085] S22: According to the formula, build a servo valve-controlled cylinder position control module in the simulation software.

[0086] like Figure 10 As shown, step S3 specifically includes the following sub-steps:

[0087] S31: Draw the 3D model of each part and component of the lunar rover motion system in the 3D design software, and set the properties of each part and component;

[0088] S32: In 3D design software, apply fit constraints between parts and components based on the actual motion and connection relationships between them;

[0089] S33: Use 3D design software to export the lunar rover motion system assembly file into XML and STL files;

[0090] S34: Read the corresponding xml file and stl file in the simulation software and build the multi-body dynamics module of the lunar rover motion system, such as Figure 12 and Figure 13 shown.

[0091] like Figure 11 As shown, step S4 specifically includes the following sub-steps:

[0092] S41: According to the world coordinate system and the actual needs of the electromechanical-hydraulic control simulation platform of the lunar rover motion system, set the basic parameters including gravity acceleration;

[0093] S42: In the multi-body dynamics module, according to the actual relationship between the lunar rover motion system and the ground, a corresponding contact force module is added. The first coordinate transformation module Transform1 is used to make the front wheels 7 and the main wheels 16 of the lunar rover motion system contact the ground, and the basic parameters of the contact model including stiffness, damping, and friction coefficient are set.

[0094] S43: Control signal X p Input to the multi-body dynamics module, measure the sensor signal Force, and input Force as the load force of the servo valve-controlled cylinder to the servo valve-controlled cylinder position control module;

[0095] S44: The cylinder structure and piston structure of the servo valve control cylinder are connected through a moving pair, which drives the input signal X of the component. p As input, the position sensor signal P, velocity sensor signal V and force sensor signal F of the moving pair are used. p As output, it completes the real-time control and monitoring of the servo valve control cylinder of the drive component, and converts the force sensing signal F p As the load force input to the hydraulic system, it completes the closed-loop control of the servo valve control cylinder of the drive component and completes the construction of the electromechanical and hydraulic control simulation platform for the lunar rover motion system;

[0096] S45: Run the electromechanical and hydraulic control simulation platform of the lunar rover motion system. The visualization interface of the simulation platform is as follows: Figures 14a-14b shown.

[0097] like Figure 15 As shown, step S5 specifically includes the following sub-steps:

[0098] S51: verifying the expected displacement of the servo valve-controlled cylinder obtained by theoretical calculation, the actual displacement of the servo valve-controlled cylinder obtained by the servo valve-controlled cylinder position control module, and the simulated displacement measured by the electromechanical-hydraulic control simulation platform;

[0099] S52: Compare and verify the expected angle of the payload cabin of the lunar rover motion system and the simulated measurement angle results.

[0100] like Figure 16 As shown in the figure, the three curves of theoretical expected displacement, actual controlled displacement and simulated measured displacement almost completely overlap with each other, and the error is relatively small, which verifies the accuracy of the servo valve-controlled cylinder position control, ensures the precise control of the servo valve-controlled cylinder of each drive component, and thus ensures the precise tilt control of the desired angle of the cargo cabin.

[0101] like Figure 17 As shown in the figure, the theoretical expected angle and the simulated measured angle are almost completely consistent, which verifies the accuracy of the electromechanical-hydraulic control simulation platform of the lunar rover motion system and the effectiveness of the simulation platform construction method.

[0102] Specifically, the front drive assembly 1 of the present invention detects the hydraulic cylinder force sensing signal and displacement sensing signal of the front drive assembly 1 through the installed first force sensor 9 and the first displacement sensor 13, monitors the working status of the front drive assembly 1 in real time, and realizes closed-loop control of the front drive assembly 1 through the first servo valve 11. By controlling the displacement change between the front hydraulic cylinder 10 and the front piston rod 12, the lifting and lowering of the front drive assembly 1 is realized, and then the coordinated movement with the main drive assembly 4 realizes the lifting and tilting movement of the cargo cabin 2 of the cargo lunar rover motion system.

[0103] The main drive assembly 4 detects the hydraulic cylinder force sensing signal and displacement sensing signal of the main drive assembly 4 through the installed second force sensor 17 and the second displacement sensor 21, monitors the working status of the main drive assembly 4 in real time, and realizes closed-loop control of the main drive assembly 4 through the second servo valve 19. By controlling the displacement change between the main hydraulic cylinder barrel 18 and the main piston rod 20, the lifting and lowering of the main drive assembly 4 is realized, and then coordinated with the front drive assembly 1 to complete the lifting and tilting movement of the cargo cabin 2 of the cargo lunar rover motion system.

[0104] In addition, a posture sensor 3 is installed at the bottom of the cargo cabin 2, which monitors the tilt angle of the cargo cabin 2 of the cargo rover motion system in real time through the posture sensor 3, and then combines the kinematic equation of the cargo rover motion system to perform real-time control of the tilt movement of the cargo cabin 2.

[0105] The method for building an electromechanical and hydraulic control simulation platform for a lunar rover motion system of the present invention includes a kinematics module, a servo valve-controlled cylinder position control module and a multi-body dynamics module. The kinematics module is established by mathematical modeling to obtain the expected displacement of the servo valve-controlled cylinder according to the expected tilt angle of the lunar rover motion system; the servo valve-controlled cylinder position control module is established by mechanism modeling based on the structure and mathematical model of the servo valve-controlled cylinder; the multi-body dynamics module is established based on the mechanical structure and material properties of the lunar rover motion system; the electromechanical and hydraulic control simulation platform of the lunar rover motion system is jointly built based on the kinematics module, the servo valve-controlled cylinder position control module and the multi-body dynamics module, as well as the control signal and sensor signal flow relationship between each module.

[0106] The carrier lunar rover motion system can realize the tilting motion of the carrier lunar rover motion system through the coordinated motion of the front drive component 1 and the main drive component 4, and can monitor the working status of the carrier lunar rover motion system in real time by building an electromechanical-hydraulic control simulation platform for the carrier lunar rover motion system, and verify the correctness of the relevant theoretical methods through simulation results.

[0107] Preferably, the main wheel 16 of the main drive assembly 4 is installed toward the second end of the cargo compartment 2 because when the front wheel 7 of the front drive assembly 1 contacts the ground, the direction of the force acting on the entire front drive assembly 1 is from the contact point of the front wheel 7 with the ground upward to the second end of the cargo compartment 2. If the main wheels 16 of the four main drive assemblies 4 are all installed toward the first end of the cargo compartment 2, the direction of the force they receive is also from the contact point of the main wheel 16 with the ground toward the second end of the cargo compartment 2. In this case, the stability of the entire cargo rover motion system is poor, and the cargo compartment 2 is prone to tipping over when carrying cargo. When the main wheels 17 of the four main drive assemblies 4 are all installed toward the second end of the cargo compartment 2, this situation can be avoided and the stability of the cargo rover motion system is increased.

[0108] The above description is a preferred embodiment of the present application, which does not limit the scope of protection of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of this technology, and these improvements and modifications should also be regarded as the scope of protection of this application.

Claims

1. A method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system, characterized in that: The cargo lunar rover motion system includes a front drive assembly, a cargo cabin, a posture sensor and a main drive assembly. The front drive assembly is arranged at the first end of the cargo compartment, the main drive assembly is arranged at the second end of the cargo compartment, and the posture sensor is arranged on the second end surface of the cargo compartment, and the posture sensor is located between the front drive assembly and the main drive assembly; The front drive assembly includes a first cargo compartment connecting plate, a front support rod, a front wheel, a second cargo compartment connecting plate, a first force sensor, a front hydraulic cylinder, a first servo valve, a front piston rod and a first displacement sensor. The first cargo compartment connecting plate is hinged to the first end of the front support rod and is installed on the first end of the cargo compartment by screws. The second end of the front support rod is installed with the front wheel, and a rotation pair is formed between the front wheel and the front support rod. The first end of the front hydraulic cylinder is hinged to the second cargo compartment connecting plate and is installed on the cabin body of the cargo compartment through the second cargo compartment connecting plate. The first end of the front hydraulic cylinder is installed with the first force sensor, the first servo valve is installed on the first side of the central position, and the first displacement sensor is installed on the second side. The front piston rod is installed in the cylinder body of the front hydraulic cylinder, and the second end is connected to the midpoint of the front support rod by a hinge seat, and the front piston rod and the front hydraulic cylinder form a moving pair. The main drive assembly includes a main support rod, a rocker arm, a main wheel, a second force sensor, a main hydraulic cylinder, a second servo valve, a main piston rod and a second displacement sensor. The first end of the main support rod is fixedly mounted on the body of the cargo compartment by bolts, and the second end is hinged to the first end of the rocker arm by a hinge. The first end of the main support rod is fixedly provided with a cantilever, and the first end of the main hydraulic cylinder is hinged to the second end of the cantilever by a hinge. The first end of the main hydraulic cylinder is installed with a second force sensor, a second servo valve is installed on the first side of the central position, and a second displacement sensor is installed on the second side. A main piston rod is installed in the cylinder body of the main hydraulic cylinder, and a moving pair is formed between the main hydraulic cylinder and the main piston rod, a main wheel is installed on the second end of the rocker arm, and a rotating pair is formed between the rocker arm and the main wheel, and the second end of the main piston rod is hinged to the second end of the rocker arm to form a rotating pair. The method comprises the following steps: S1: Based on the mechanical structure and expected tilt angle of the lunar rover motion system, the kinematic equation of the lunar rover motion system is established, and the displacement of the servo valve-controlled cylinder of the front drive component and the main drive component of the lunar rover motion system is planned to obtain the expected displacement of the servo valve-controlled cylinder. The process includes the following sub-steps: S11: Based on the mechanical structure of the lunar rover motion system, establish the kinematic model of the front drive components of the lunar rover motion system. Where Xr0 represents the extension of the hydraulic cylinder of the front drive assembly, CD represents the distance between points C and D, DE represents the distance between points D and E, BD represents the distance between points B and D, DF represents the distance between points D and F, p represents the distance between points B and F, ∠FDE represents the angle between points FD and ED, l 00 Indicates the distance between point C and point E at the initial position; S12: Based on the mechanical structure of the lunar rover motion system, establish the kinematic model of the main drive components of the lunar rover motion system. Where Xr3 represents the extension of the hydraulic cylinder of the rear main drive assembly, GH represents the distance between points G and H, HI represents the distance between points H and I, HK represents the distance between points H and K, d represents the distance between points G and K, ∠IHK represents the angle between points IH and KH, l 03 Indicates the distance between point G and point I at the initial position; S2: The expected displacement of the servo valve-controlled cylinder of the front drive assembly and the main drive assembly and the force sensing signal collected by the multi-body dynamics model are used as input to obtain the actual displacement of the servo valve-controlled cylinder through the servo valve-controlled cylinder position control module; S3: Draw a 3D model of the lunar rover motion system and use the multi-body dynamics tool library in the simulation software to build a multi-body dynamics module for the lunar rover motion system. S4: Build a mechatronic hydraulic control simulation platform for the lunar rover motion system by integrating the kinematics module, servo valve-controlled cylinder position control module, and multi-body dynamics module, as well as the flow of control and sensor signals between these modules. S5: Verify the simulation results of the servo valve-controlled cylinder displacement and the cargo cabin angle of the electromechanical-hydraulic control simulation platform of the cargo lunar rover motion system.

2. The method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system according to claim 1, characterized in that: The main wheel of the main driving assembly is installed toward the second end of the cargo compartment.

3. The method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system according to claim 1 or 2, characterized in that: There are four main drive assemblies in total, which are symmetrically distributed on both sides of the first symmetry plane of the cargo compartment.

4. The method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system according to claim 1, characterized in that: Step S2 specifically includes the following sub-steps: S21: By analyzing the structure and control principle of the servo valve control cylinder, the state variables are selected as x1=x p , x3=p L , we get the state space equation of the servo valve controlled cylinder system, in, x1, x2, x3 are the three state variables of the state space equation of the servo valve control cylinder system. Represents the first-order derivative of x1, x2, x3 with respect to time, x p Indicates the displacement of the servo valve control cylinder piston, Represents x p The first derivative with respect to time, p L Indicates the load pressure of the servo valve control cylinder, K indicates the load stiffness, B p Represents the viscous damping coefficient of the load and servo valve control cylinder, m t Indicates the total mass converted to the servo valve control cylinder piston, A1 represents the area of ​​the rodless cavity of the asymmetric hydraulic cylinder, n represents the ratio of the area of ​​the rod cavity to the rodless cavity of the asymmetric hydraulic cylinder, C ip Indicates the leakage coefficient of the hydraulic cylinder, C ep Indicates the external leakage coefficient of the hydraulic cylinder, k d Indicates the reduced flow coefficient, k PID Indicates PID gain, k axv Indicates the servo valve gain, P s Indicates the oil supply pressure, V indicates the total volume of the chamber, β e Represents the viscous damping coefficient of the load and the servo valve control cylinder, u1 and u2 represent two input variables, where u1 = x r , u2=F L , x r Indicates the expected displacement of the servo valve controlled cylinder, F L represents the load force of the servo valve controlled cylinder, and y represents the system output variable; S22: According to the formula, build a servo valve-controlled cylinder position control module in the simulation software.

5. The method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system according to claim 1, characterized in that: Step S3 specifically includes the following sub-steps: S31: Draw a 3D model of each part and component of the lunar rover motion system in 3D design software and set the properties of each part and component; S32: In 3D design software, apply fit constraints between parts and components based on the actual motion and connection relationships between them; S33: Use 3D design software to export the lunar rover motion system assembly file into XML and STL files; S34: Read the corresponding xml file and stl file in the simulation software to build the multi-body dynamics module of the lunar rover motion system.

6. The method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system according to claim 1, characterized in that: Step S4 specifically includes the following sub-steps: S41: According to the world coordinate system and the actual needs of the electromechanical-hydraulic control simulation platform of the lunar rover motion system, set the basic parameters including gravity acceleration; S42: In the multi-body dynamics module, according to the actual relationship between the lunar rover motion system and the ground, a corresponding contact force module is added. The wheels of the lunar rover motion system are brought into contact with the ground through the first coordinate transformation module Transform1, and the basic parameters of the contact model including stiffness, damping, and friction coefficient are set. S43: Control signal X p Input to the multi-body dynamics module, measure the sensor signal Force, and input Force as the load force of the servo valve-controlled cylinder to the servo valve-controlled cylinder position control module; S44: The cylinder structure and piston structure of the servo valve control cylinder are connected through a moving pair, which drives the input signal X of the component. p As input, the position sensor signal P, velocity sensor signal V and force sensor signal F of the moving pair are used. p As output, it completes the real-time control and monitoring of the servo valve control cylinder of the drive component, and converts the force sensing signal F p As the load force input to the hydraulic system, it completes the closed-loop control of the servo valve control cylinder of the drive component and completes the construction of the electromechanical and hydraulic control simulation platform for the lunar rover motion system; S45: An electromechanical and hydraulic control simulation platform for the lunar rover's motion system.

7. The method for constructing an electromechanical-hydraulic control simulation platform for a lunar rover motion system according to claim 1, characterized in that: Step S5 specifically includes the following sub-steps: S51: verifying the expected displacement of the servo valve-controlled cylinder obtained by theoretical calculation, the actual displacement of the servo valve-controlled cylinder obtained by the servo valve-controlled cylinder position control module, and the simulated displacement measured by the electromechanical-hydraulic control simulation platform; S52: Compare and verify the expected angle of the payload cabin of the lunar rover motion system and the simulated measurement angle results.

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