Modular tracked vehicle dynamics model construction method and distributed control method

Abstract

The application discloses a modular tracked vehicle dynamics model construction method and a distributed control method, and belongs to the field of vehicle modeling and control. The construction method comprises the following steps: in tracked unit local modeling, the contact force is calculated by using a magic formula and a suspension balance equation, equivalent longitudinal, lateral and vertical stiffnesses are extracted, and nonlinear stress is reduced to linear output variables; in whole vehicle modeling, a six-degree-of-freedom state space matrix is constructed, the tracked unit output variables are taken as system inputs, and the whole vehicle state is taken as system outputs, so that weak coupling of dynamics is realized. Based on this, the control method configures each tracked unit as a distributed computing node containing an independent ECU, performs weak coupling interaction through a network, each node calls a local equation constructed based on equivalent stiffness, independently solves an optimal control law and drives execution. The application overcomes the calculation power bottleneck of centralized control, realizes flexible and seamless expansion suitable for different tracked quantity configurations, and significantly improves the fault-robustness of the system.

Description

Technical Field

[0001] This invention belongs to the field of vehicle modeling and control, specifically involving a method for constructing a dynamic model of a modular tracked vehicle and a distributed control method. Background Technology

[0002] With the development of modern engineering technology, tracked vehicles, as an important type of special vehicle, are widely used in agriculture, military, mining, and other fields. Especially in complex terrain and harsh environments, tracked vehicles have gained widespread application due to their superior passability and stability. The design and control system of tracked vehicles are key factors in their performance and operational efficiency, and vehicle modeling and control are important topics in tracked vehicle research.

[0003] Traditional tracked vehicle modeling methods are usually based on centralized control of the overall system, that is, modeling and controlling the entire vehicle as a unified system. This method tightly couples different functional modules (such as drive, steering, suspension, etc.), resulting in poor system flexibility, high failure rate, insufficient scalability, and cumbersome debugging and optimization process, making it difficult to adapt to changing tasks and working environments.

[0004] With the development of vehicle technology, modular design, which studies each subsystem independently, has gradually become an important trend. However, existing modular modeling methods still face some challenges, mainly in terms of the accuracy of module and vehicle dynamics modeling, the coordination of inter-module collaboration, and the real-time performance of control algorithms. Therefore, how to construct a more efficient, flexible, and easily scalable modular modeling method for tracked vehicles remains an important research topic in the current technical field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for constructing a modular tracked vehicle dynamics model and a distributed control method, thereby solving the problems in the existing technologies.

[0006] The objective of this invention can be achieved through the following technical solutions: The method for constructing a modular tracked vehicle dynamics model includes: Local modeling steps for track units: For each modular track unit, establish the rotational dynamics equation of the drive wheel and the vertical dynamics equation of the suspension respectively; calculate the nonlinear horizontal shear force of the track plate below the road wheel using the magic formula, and calculate the vertical force in combination with the suspension vertical dynamics equation; divide the nonlinear horizontal shear force by the corresponding slip velocity to extract the equivalent longitudinal stiffness and equivalent lateral stiffness, and divide the vertical force by the corresponding static deformation of the suspension to extract the equivalent vertical stiffness; based on the equivalent longitudinal stiffness, equivalent lateral stiffness, and equivalent vertical stiffness, express the forces in each direction on the track unit as output variables that vary linearly with the working conditions; The steps for weakly coupled vehicle modeling are as follows: Establish a six-degree-of-freedom (DOF) dynamic equation for the vehicle, including longitudinal, lateral, vertical, yaw, pitch, and roll axes; reconstruct the six-DOF dynamic equation into a state-space matrix form; in the state-space matrix, configure the output variables of each track unit as input parameters of the system through an input distribution matrix, and configure the six-DOF state variables of the entire vehicle as output parameters of the system, thereby constructing the vehicle dynamic equation with weakly coupled interaction between the track units and the overall vehicle dynamics.

[0007] Furthermore, the extraction process of the equivalent longitudinal stiffness and equivalent lateral stiffness includes: Obtain the longitudinal slip velocity of the track pads below the road wheels. and lateral slip velocity And calculate the combined slip velocity. ; Based on the magic formula, the longitudinal shear force under pure slip conditions is calculated. and transverse shear force ; Will and By multiplying each by the ratio of the corresponding slip velocity to the combined slip velocity, and combining this with the vector direction opposite to the slip direction, the longitudinal shear force under the combined slip condition can be calculated. and transverse shear force ; Will and The ratio is defined as the dynamic equivalent longitudinal stiffness. ,Will and The ratio is defined as the dynamic equivalent lateral stiffness. ; The parameters of the magic formula are obtained by collecting samples of track slip velocity, normal load and shear force through hard road traction test or slip ratio sweep frequency test, and then using least squares fitting. When the slip velocity is less than a preset threshold, the first-order slope of the magic formula at zero point or the preset basic stiffness is used as the equivalent stiffness to avoid division by zero.

[0008] Furthermore, the local modeling step of the track unit also includes a model set registration mechanism: A linearized track element model set consisting of equivalent stiffness sets under different working conditions is pre-established; The speed and attitude features of the whole vehicle are extracted in real time, and the corresponding equivalent stiffness parameters are dynamically adapted and called from the model set through feature matching to update the output variables of the track unit. The speed and attitude state features include at least the following: vehicle longitudinal speed, lateral speed, yaw rate, pitch angle, roll angle, longitudinal acceleration, lateral acceleration, road adhesion coefficient, and track combination slip speed; the feature matching includes: rule matching based on speed threshold, yaw rate threshold, attitude angle threshold, and adhesion coefficient range, or nearest working condition matching based on weighted Euclidean distance.

[0009] Furthermore, the equivalent vertical stiffness extraction process includes: Taking a single track unit and its equivalent vehicle body mass above it as the research object, and considering a single road wheel and its suspension system as a mass-spring-damping system, the force balance equation is established. The net suspension force on the equivalent vehicle body is calculated based on the force balance equation, and the ratio of the net suspension force to the static deformation of the suspension is extracted as the equivalent vertical stiffness.

[0010] Furthermore, the expression for the state space matrix is: in, This represents the six-degree-of-freedom state variables of the entire vehicle; Represents the vehicle state matrix; The output variable represents the longitudinal force, lateral force, and vertical force of the i-th track unit; Let r represent the input distribution matrix, where r is the total number of track unit modules.

[0011] A distributed control method for modular tracked vehicles is applied to tracked vehicles comprising multiple track unit modules and a vehicle communication network. The control method is based on the vehicle dynamics equations established by the aforementioned dynamics model construction method and includes the following steps: Node configuration steps: Configure each track unit module as an independent distributed computing node, and equip each track unit module with an electronic control unit (ECU) with independent computing capabilities; State interaction steps: Each ECU performs a weakly coupled interaction between the track unit module and the vehicle state through the vehicle communication network, and obtains the global state variables of the vehicle and the state information of adjacent track unit modules in real time. Independent calculation steps: Each ECU calls the local state space equation of the track unit constructed based on the equivalent longitudinal stiffness, equivalent lateral stiffness and equivalent vertical stiffness, and uses the global state variables and the state information of adjacent track unit modules as boundary inputs to independently calculate the optimal control law of this node. The optimal control law includes the target value of track traction force. Drive execution steps: Each ECU generates a drive wheel motor torque command based on the track traction target value in the optimal control law, and independently drives the corresponding track unit module.

[0012] Furthermore, the weakly coupled interaction process between the track unit module and the overall vehicle state includes: Each ECU independently calculates the local forces and uses them as output variables. Send to the vehicle coordination node via the vehicle communication network; The update of the overall vehicle status depends only on the output variables uploaded to each track unit node. State-space matrix operations are performed, and each ECU independently solves the microscopic force problem during the track slippage process locally.

[0013] Furthermore, the local state-space equation of the track unit is in the form of: in, This is the state vector of this node module itself. This is the control input matrix for this node. Let be the road surface excitation vector. These are the state vectors of neighboring modules obtained through the network. These are the corresponding coefficient matrices; the elements of the coefficient matrices contain the equivalent stiffness updated based on the real-time slip velocity.

[0014] Furthermore, the process of generating the drive wheel motor torque command includes: Establish rotational dynamic equations that include track traction, equivalent resistance of a single track, and overall equivalent rotational inertia of the drive wheel; The ECU substitutes the target value of the track traction force into the rotational dynamics equation, calculates the target driving torque of the motor in reverse, and sends it to the motor controller of the drive wheel.

[0015] An electronic device includes: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus; The memory is used to store at least one executable instruction that causes the processor to perform an operation corresponding to the modeling method described above or the control method described above.

[0016] The beneficial effects of this invention are: 1. In the track unit modeling step, this invention calculates the nonlinear contact shear force and vertical force, and then further transforms them into linear forms related to slip velocity or deformation (i.e., extracting equivalent longitudinal, lateral, and vertical stiffness). A model working condition matching mechanism is introduced to dynamically adapt the stiffness parameters. The nonlinear dynamic equations are reduced in dimension and linearized through stiffness extraction. At the same time, the working condition matching mechanism is used to compensate for the accuracy deviation caused by linearization. Thus, while ensuring that the dynamic model can truly reflect the interaction characteristics between the track and the ground, the computational scale of the control optimization problem is significantly reduced, providing a dynamic model that can be practically deployed on the vehicle controller and meets the requirements of real-time operation.

[0017] 2. This invention constructs a vehicle dynamics equation that is "weakly coupled" with the output variables of the tracked units (taking the force on one side of the track as the system input and the overall vehicle state as the output). Based on this, each tracked unit is equipped with an independent ECU, which is treated as a distributed computing node. This weakly coupled physical and mathematical architecture breaks the constraints of traditional centralized control. When faced with the needs of different vehicle configurations, this architecture is not only applicable to conventional dual-tracked vehicles, but also to four-tracked or half-tracked vehicles. Only adding or removing module nodes in the network and updating the input dimension of the state matrix are required, without affecting the integrity of the existing module controller and the entire control architecture, thus achieving flexible expansion of the control system.

[0018] 3. In the control architecture design of this invention, each modular tracked unit node independently solves its own local optimal control law through real-time communication and game theory decision-making, rather than relying on a single vehicle controller for centralized allocation; the distributed network architecture realizes the decentralization of control authority and computing power, reducing the impact of local execution node failures or communication delays on the overall state of the vehicle; even if individual modules malfunction in complex and harsh environments, the system can still maintain basic stable operation, improving the overall robustness of the tracked vehicle control system.

[0019] 4. This invention delves into the internal structure of the track unit, independently constructing a pure slip and combined slip track plate grounding model based on the magic formula, a drive wheel rotation dynamics model, and a vertical dynamics model that simplifies the equivalent vehicle body and road wheels into a mass-spring-damping system. This avoids estimating the tracked vehicle as a fuzzy whole and effectively and intuitively describes the force characteristics of the track unit module itself in each degree of freedom of motion (longitudinal, lateral, vertical, etc.). This provides a solid data foundation for understanding the coupling relationship between track modules and between the track unit and the dynamic behavior of the whole vehicle. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the tracked vehicle of the present invention; Figure 2 This is an equivalent model diagram of the suspension system of the present invention; Figure 3 This is a vertical model diagram of the single-sided track unit of the present invention; Figure 4 This is a planar motion model diagram of the tracked vehicle of the present invention; Figure 5 This is a schematic diagram of the linearization model working condition matching mechanism of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To avoid ambiguity in the formula symbols, in the following embodiments, i represents the track unit number, and j represents the road wheel or track plate number within a single track unit; unless otherwise specified, the subscripts L and R represent the left and right track sides, respectively, and x, y, and z represent the longitudinal, lateral, and vertical directions, respectively; dotted variables represent the first-order time derivative of the corresponding physical quantity, and dotted variables represent the second-order time derivative of the corresponding physical quantity.

[0024] Example 1 The method for constructing a modular tracked vehicle dynamics model includes the following steps: Step 1: Tracked vehicle model analysis and reasonable assumptions To balance the complexity and accuracy of the model, it is assumed that the ground forces acting on the tracked vehicle are only the longitudinal, lateral, and vertical forces acting on the track plates under the road wheels. This model closely approximates the actual stress distribution, avoiding numerical integration of the longitudinal forces, lateral forces, and steering resistance torque generated by the track sections in contact with the ground.

[0025] It should be noted that the schematic diagram of the tracked vehicle is as follows: Figure 1 As shown, in this embodiment, only the appendix... Figure 1 The tracked vehicle shown is analyzed, while only considering that the tracked vehicle travels on a hard surface.

[0026] Step 2: Construct a grounding model for the track plates beneath the road wheels. The relationship between the longitudinal force, lateral force, and slip velocity at the contact point between the track and the ground is expressed as follows: In the formula, , These represent the longitudinal and lateral sliding velocities of the track pads beneath the road wheels, respectively. , These represent the longitudinal and lateral velocities at the center of the road wheel, respectively. This indicates the slip speed of the track plates below the road wheels.

[0027] Unlike the continuous deformation on soft surfaces, when tracked vehicles travel on hard surfaces, the shear force provided by the road surface to the tracks is only related to the local road surface characteristics beneath the tracks. The ground shear force can be considered a function of the relative velocity of the tracks; as the relative velocity increases, the shear force increases linearly before reaching a saturation value. This nonlinear track-ground contact characteristic is described by the magic tire formula.

[0028] The longitudinal and lateral forces at the contact point between the ground track and the ground are expressed as follows: In the formula, , These represent the longitudinal and lateral shear forces under pure longitudinal and lateral slip conditions of the track plates below the road wheels, respectively. ); Indicates the coefficient of adhesion of the road surface; , These represent the longitudinal and lateral shear forces under combined slip conditions of the track plates below the road wheels. ). , , These represent the parameters of the magic tire, indicating pure longitudinal shear force. , , These represent the parameters of the magic tire, which represent the pure lateral shear force.

[0029] The parameters of different magic tires are identified based on different road surface measurement data to ensure the accuracy of the model.

[0030] Specifically, the identification process of the magic formula parameters includes: setting up a traction meter, wheel speed encoder, inertial measurement unit and vertical load sensor on the hard road surface to be calibrated, so that the vehicle can perform pure longitudinal slip test and pure lateral slip test under a preset normal load Fzij; obtaining different slip speed sampling points by changing the drive wheel speed or lateral drag speed, and collecting the corresponding longitudinal shear force Fx0,ij, lateral shear force Fy0,ij, combined slip speed vs,ij and normal load Fzij.

[0031] After obtaining the test samples, with the goal of minimizing the sum of squared residuals between the measured shear force and the calculated value using the magic formula, nonlinear least squares fitting was performed on the pure longitudinal parameters Dx, Cx, Bx and the pure transverse parameters Dy, Cy, By respectively. After the fitting was completed, the parameters obtained under different road surfaces, different adhesion coefficients and different load ranges were stored in a parameter table or model set for the vehicle ECU to call according to real-time operating conditions.

[0032] The slip velocity of the track plate under each road wheel is calculated using the following formula.

[0033] In the formula, Indicates the distance between the two tracks ( ); These represent the distances between each load-bearing wheel and the vehicle's center of gravity along the X direction. ).

[0034] Step 3: Construct the rotational dynamics model of the tracked vehicle's drive wheels. In this embodiment, the tracked vehicle is driven by a motor and is subjected to the combined effects of track traction force and equivalent resistance. Taking a single-sided track unit as the research object, a rotational dynamics equation is established, expressed as: In the formula, Indicates the torque of the drive wheel motor ( ), Indicates the speed of the drive wheels ( ), Indicates the equivalent radius of rotation of the drive wheel ( ), Represents the overall equivalent rotational inertia of a single track ( ), For single-sided track traction, The equivalent resistance of a single-sided track.

[0035] The equation of rotational dynamics is expressed as: Equivalent resistance of one track It is the combined effect of internal and external resistance, expressed as: In the formula, The rolling resistance coefficient, This is the coefficient of rotational resistance torque within the system.

[0036] Step 4: Construct the vertical dynamic model of the track unit. We consider a single road wheel, its overhead suspension system, and the equivalent vehicle mass as a single system for study. This system, simplified, is a typical mass-spring-damped system. We establish its force equilibrium equations and combine them with... Figure 2 , is represented as: In the formula, Indicates the equivalent vehicle mass above the suspension. Indicates the mass of the road wheel. Indicates the suspension damping system. Indicates the suspension spring stiffness. This represents the equivalent vertical displacement of the vehicle body above the road wheel suspension. The vertical displacement of the load-bearing wheel is indicated. This is for excitation of road surface unevenness displacement.

[0037] like Figure 3 As shown, taking a single-sided track unit and its equivalent vehicle body mass above it as the research object, the resultant force on the single-sided track is expressed as: The net suspension force on the equivalent vehicle body is: The equation of motion for the vertical motion at the center of mass of the track unit during the movement of the tracked vehicle is as follows: In the formula, For the mass of a single track unit, This indicates the vertical displacement at the center of mass of the track unit.

[0038] When the vehicle roll angle and pitch angle When the angle varies within a small range, the vertical displacement above the suspension at the center of mass of both track units is expressed as follows: In the formula, This represents the vertical displacement of the vehicle's center of mass.

[0039] The vertical displacement above the road wheel suspension is expressed as: MERGEFORMAT (1) definition , The vertical displacement above each road wheel suspension can be expressed as: The pitching moment experienced by the center of mass of a single track under the action of the resultant force can be expressed as: Step 5: Construct the six-degree-of-freedom force balance equations for the tracked vehicle. definition Considering the force balance of the tracked vehicle in the longitudinal, lateral, and yaw directions, combined with the attached... Figure 4 The dynamic equations of its planar motion are expressed as: In the formula, Indicates the total mass of the tracked vehicle ( ), This represents the moment of inertia of the tracked vehicle about the Z-axis ( ).

[0040] The lateral, longitudinal, and yaw speeds of a tracked vehicle in a geodetic coordinate system are expressed as follows: In the formula, Indicates yaw rate ( ).

[0041] Based on step four, the vertical motion of the tracked vehicle is analyzed and the force balance equations are established. The vertical motion equation at the vehicle's center of mass is expressed as follows: The equation for the vehicle's pitch motion is expressed as: The equation for the roll motion of the vehicle body is expressed as follows: In the above formula, This represents the moment of inertia of the tracked vehicle body about the Y-axis. ), This represents the moment of inertia of the tracked vehicle about the X-axis ( ).

[0042] Step Six: Dynamic Description of Track Plate Planar Stiffness and Calculation of Suspension System Vertical Stiffness The lateral and longitudinal forces calculated in real time in step two are described in a linear form related to the slip velocity, specifically as follows: In the formula, These represent the equivalent longitudinal stiffness and lateral stiffness of the track plates, respectively. Therefore, the time-varying longitudinal stiffness and lateral stiffness can be obtained from the longitudinal force, lateral force, and slip velocity, specifically expressed as follows: Furthermore, to avoid division-by-zero issues caused by zero or near-zero slip velocity during tracked starts, constant-speed straight-line travel, or on high-adhesion hard surfaces, a minimum threshold εv is set. When |v xs,ij |<εv or|v ys,ij When | < εv, F is not executed directly. xs,ij / v xs,ij or F ys,ij / v ys,ij Instead of performing division operations, the first-order slope at zero using the magic formula is used as the basic stiffness, or a preset basic stiffness k is invoked. x0,ij k y0,ij Replace the current equivalent stiffness.

[0043] In one embodiment, the foundation stiffness can be determined according to k. x0,ij =μD x F zij C x B x k y0,ij =μD y F zij C y B y Calculation; In another embodiment, the base stiffness is obtained by fitting the above-mentioned parameter identification test within a small slip range. If the slip velocity is between εv and 2εv, a linear weighted transition of base stiffness and real-time ratio stiffness is used to avoid abrupt stiffness changes.

[0044] Under static conditions, the equilibrium equations for the vertical force and moment of the tracked vehicle's road wheels are as follows: In the formula, For the vertical force of the track wheel, Vertical static deformation of the track wheel ( ), For the mass of the tracked vehicle body ( ).

[0045] Since the static deformation of the suspension is only related to the suspension force and the equivalent stiffness of the suspension, the vertical force can be described as a linear relationship between the equivalent stiffness of the suspension and the amount of suspension deformation: In the formula, Indicates suspension stiffness ( Then we have: The calculated stiffness is used to construct a linearized track element model set, as detailed in the appendix. Figure 5 As shown.

[0046] Specifically, the linearized track unit model set is based on the eigenvector χ=[v x , v y , γ, a x , a y , θ, φ,μ, v s The operating conditions are divided, where v x Let v be the longitudinal velocity. y γ is the lateral velocity, γ is the yaw rate, and a is the lateral velocity. x and a y These represent longitudinal and lateral accelerations, respectively; θ is the pitch angle; φ is the roll angle; μ is the road adhesion coefficient; and v... s The slip speed of the track combination.

[0047] As a reproducible matching rule, a low-speed straight-ahead model is matched when vx is below the low-speed threshold and |γ| is below the straight-ahead threshold; a steering model is matched when |γ| is above the steering threshold or the speed difference between the left and right tracks is above the differential threshold; a slope or roll model is matched when |θ| or |φ| is above the attitude threshold; and the corresponding road surface model is matched when μ falls into the high, medium, and low adhesion ranges, respectively. If multiple rules are triggered simultaneously, the nearest model set entry is selected based on the weighted Euclidean distance after normalization of each feature, and a hysteresis threshold is set to avoid frequent switching.

[0048] Step 7: Constructing the dynamic equations of the track element definition , , , , .in: , In the formula, X mi Let Z be the local state vector of the i-th track unit, containing the equivalent vertical displacement vector Z of the vehicle body above the suspension. usi Its velocity vector and the angular velocity w of the driving wheel i ;U i This is the control input for the i-th track unit; in this embodiment, it is the torque T of the drive wheel motor.wi ;X mci The boundary input vector is mapped from the overall vehicle state to the i-th track element, containing the vertical displacement Z of the track element. si Road surface excitation Z wi Lateral velocity V of the road wheel yi and the longitudinal speed V of the road wheel xi W i The disturbance vector contains the vertical excitation Z from the road surface. wi and road surface adhesion coefficient μ; Y i The output variable for the track unit includes the longitudinal traction force F on one side. xi The lateral force vector FYI and the vertical force vector FZI.

[0049] Z usi Z si Z wi V yi V xi FYI and FZI are vectors that correspond one-to-one with each road wheel or track plate in the i-th track unit, j=1 to 5 represent the j-th road wheel or the track plate below it in the track unit; w1 to w5 are the road excitation components at the corresponding road wheel or track plate, v yi1 to v yi5 For the lateral velocity component, F yi1 To F yi5 and F zi1 To F zi5 These are the lateral force and vertical force components, respectively.

[0050] Based on steps one through six, the dynamic equations of the track unit can be written as follows: in, , , , in, In the formula, A i Let B be the local state matrix of the i-th tracked unit. iTo control the input matrix, M i Let N be the input matrix for road surface and adhesion condition disturbances. i Let C be the boundary state coupling matrix of the entire vehicle. i and P i For the output matrix; 0 a×b Let I represent a zero matrix with a rows and b columns. 5×5 tr(·) represents a fifth-order identity matrix, and tr(·) represents the trace operation.

[0051] K xi =diag[k xi1 ,k xi2 ,k xi3 ,k xi4 ,k xi5 [K] is the equivalent longitudinal stiffness diagonal matrix. yi =diag[k yi1 ,k yi2 ,k yi3 ,k yi4 ,k yi5 [K] is the equivalent lateral stiffness diagonal matrix. si =diag[k si1 ,k si2 ,k si3 ,k si4 ,k si5 [C] is the diagonal matrix of the suspension's equivalent stiffness. si =diag[c si1 ,c si2 ,c si3 ,c si4 ,c si5 [K] is the diagonal matrix of suspension damping. ti =diag[k ti1 ,k ti2 ,k ti3 ,k ti4 ,k ti5 [m] is the diagonal matrix representing the equivalent vertical stiffness of the track-road contact area; usi Let m be the equivalent mass of the road wheel of the i-th track unit. usij J is the equivalent mass of the j-th road wheel of the i-th track unit. d R is the overall equivalent rotational inertia of the drive wheel and one side track. d μ is the equivalent rotation radius of the driving wheel. w This is the internal rotational resistance torque coefficient.

[0052] Step 8: Construct the vehicle state-space equations that are weakly coupled with the output variables of the track units. definition Based on steps one through seven, the dynamic equations of the tracked vehicle can be written in a form that is weakly coupled with the output variables of the track units: in, Among them, A s For the vehicle state matrix, H i Output variable Y for the i-th track unit i The input distribution matrix L enters the vehicle equation. i Vehicle status X c Input X to the boundary of the i-th track unit mci The mapping matrix; X c v in x v y γ and z represent the longitudinal velocity, lateral velocity, and yaw rate of the vehicle, respectively. s Let θ be the vertical displacement of the vehicle's center of mass, φ be the pitch angle, and φ be the roll angle.

[0053] M is the total mass of the tracked vehicle, m s For vehicle body mass, I zz Let I be the moment of inertia of the entire vehicle about the Z-axis. yy B is the moment of inertia of the entire vehicle about the Y-axis; i Let I be the lateral offset distance of the i-th track element relative to the vehicle's center of gravity. j Let x be the longitudinal distance of the j-th road wheel relative to the vehicle's center of gravity. dev I is the longitudinal correction amount for the track unit installation position relative to the nominal position; 1×5 I 5×1 and I 5×4 These represent either a matrix of all ones or a selection matrix in the corresponding dimension, 0 and 1 respectively. a×b Represents the zero matrix of the corresponding dimension.

[0054] Example 2 A distributed control method for modular tracked vehicles is applied to tracked vehicles comprising multiple track unit modules and a vehicle communication network. This control method is based on the vehicle dynamic equations established by the aforementioned dynamic model construction method, and specifically includes the following steps: S1, Node configuration steps: Configure each track unit module as an independent distributed computing node, and equip each track unit module with an electronic control unit (ECU) with independent computing capabilities; S2, State Interaction Steps: Each ECU performs a weakly coupled interaction between the track unit module and the vehicle state through the vehicle communication network, and obtains the global state variables of the vehicle and the state information of adjacent track unit modules in real time. The weakly coupled interaction process between the track unit module and the overall vehicle status includes: After each ECU independently calculates the local forces, it sends the results as output variables to the vehicle coordination node through the vehicle communication network. The update of the overall vehicle status depends only on the output variables uploaded to each track unit node. State-space matrix operations are performed, and each ECU independently solves the microscopic force problem during the track slippage process locally.

[0055] S3, Independent Calculation Step: Each ECU calls the local state space equation of the track unit constructed based on the equivalent longitudinal stiffness, equivalent lateral stiffness and equivalent vertical stiffness, and uses the global state variables and the state information of adjacent track unit modules as boundary inputs to independently calculate the optimal control law of this node. The optimal control law includes the target value of track traction force. Specifically, each ECU sends its current state in the prediction time domain N to its adjacent ECUs within each control cycle. p The predicted output sequence Y within i (k+τ|k) and boundary state X mci (k+τ|k), where τ=1,2,…,N p The predicted output sequence includes at least the longitudinal traction force F. xi The boundary conditions include lateral force FYI and vertical force FZI, and the boundary state includes at least boundary displacement, boundary velocity, predicted track speed and predicted slip velocity.

[0056] Each ECU constructs a local objective function J. i J i It includes at least the tracking error term between the desired state and the predicted state of the whole vehicle, the energy consumption term of the drive motor, the control input incremental smoothing term, and the boundary output consistency term of adjacent nodes; at the same time, the maximum torque of the motor, the track-ground adhesion limit, the suspension travel and the upper limit of track traction are set as constraints.

[0057] The specific forms of the local state-space equations for the tracked unit include: in, This is the state vector of this node module itself. This is the control input matrix for this node. Let be the road surface excitation vector. These are the state vectors of neighboring modules obtained through the network. These are the corresponding coefficient matrices; the elements of the coefficient matrices contain the equivalent stiffness updated based on the real-time slip velocity.

[0058] During the solution process, each ECU uses the alternating direction multiplier method for distributed iteration: First, the consistency variables and Lagrange multipliers are initialized based on the solution of the previous cycle or the broadcast value of the vehicle coordination node; then, each ECU solves the constrained quadratic programming problem locally to obtain the predictive control sequence of this node; then, adjacent ECUs exchange boundary predictions and update the consistency variables and multipliers; when both the original residual and the dual residual are less than the preset threshold, or when the number of iterations reaches the upper limit, the first track traction target value in the predictive control sequence of this node is output and the next control cycle begins.

[0059] S4, Drive execution steps: Each ECU generates a drive wheel motor torque command based on the track traction target value in the optimal control law, and independently drives the corresponding track unit module.

[0060] The specific process for generating the drive wheel motor torque command is as follows: Establish rotational dynamic equations that include track traction, equivalent resistance of a single track, and overall equivalent rotational inertia of the drive wheel; The ECU substitutes the target value of the track traction force into the rotational dynamics equation, calculates the target driving torque of the motor in reverse, and sends it to the motor controller of the drive wheel.

[0061] Furthermore, the distributed control method has a topology dynamic expansion mechanism, specifically including: When adding or removing track unit modules in the vehicle communication network, the optimal control law solution logic in the ECU of the existing module remains unchanged; The dimension of the input distribution matrix corresponding to the vehicle state equation is updated only based on the physical location of the access or removal module, so as to achieve adaptive control of vehicles with different track unit configurations.

[0062] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for constructing a modular tracked vehicle dynamics model, characterized in that, include: Local modeling steps for track units: For each modular track unit, establish the rotational dynamics equation of the drive wheel and the vertical dynamics equation of the suspension respectively; The nonlinear horizontal shear force on the track plate below the road wheel is calculated using the magic formula, and the vertical force is calculated in conjunction with the vertical dynamic equation of the suspension. The nonlinear horizontal shear force is divided by the corresponding slip velocity to extract the equivalent longitudinal stiffness and equivalent lateral stiffness, and the vertical force is divided by the corresponding static deformation of the suspension to extract the equivalent vertical stiffness. Based on the equivalent longitudinal stiffness, equivalent lateral stiffness, and equivalent vertical stiffness, the forces in each direction on the track unit are expressed as output variables that vary linearly with the working conditions. The steps for weakly coupled vehicle modeling are as follows: Establish a six-degree-of-freedom (DOF) dynamic equation for the entire vehicle, including longitudinal, lateral, vertical, yaw, pitch, and roll axes; reconstruct the six-DOF dynamic equation into a state-space matrix form; in the state-space matrix, configure the output variables of each track unit as input parameters of the system through an input distribution matrix, and configure the six-DOF state variables of the entire vehicle as output parameters of the system, thereby constructing the vehicle dynamic equation with weakly coupled interaction between the track units and the overall vehicle dynamics.

2. The method for constructing a modular tracked vehicle dynamics model according to claim 1, characterized in that, The extraction process of the equivalent longitudinal stiffness and equivalent lateral stiffness includes: Obtain the longitudinal slip velocity of the track pads below the road wheels. and lateral slip velocity And calculate the combined sliding velocity. ; Based on the magic formula, the longitudinal shear force under pure slip conditions is calculated. and transverse shear force ; Will and By multiplying each by the ratio of the corresponding slip velocity to the combined slip velocity, and combining this with the vector direction opposite to the slip direction, the longitudinal shear force under the combined slip condition can be calculated. and transverse shear force ; Will and The ratio is defined as the dynamic equivalent longitudinal stiffness. ,Will and The ratio is defined as the dynamic equivalent lateral stiffness. ; The parameters of the magic formula are obtained by collecting samples of track slip velocity, normal load and shear force through hard road traction test or slip ratio sweep frequency test, and then using least squares fitting. When the slip velocity is less than a preset threshold, the first-order slope of the magic formula at zero point or the preset basic stiffness is used as the equivalent stiffness to avoid division by zero.

3. The method for constructing a modular tracked vehicle dynamics model according to claim 1, characterized in that, The local modeling step of the track unit also includes a model set registration mechanism: A linearized track element model set consisting of equivalent stiffness sets under different working conditions is pre-established; The speed and attitude features of the whole vehicle are extracted in real time, and the corresponding equivalent stiffness parameters are dynamically adapted and called from the model set through feature matching to update the output variables of the track unit. The speed and attitude characteristics include at least the following: longitudinal speed, lateral speed, yaw rate, pitch angle, roll angle, longitudinal acceleration, lateral acceleration, road adhesion coefficient, and track combination slip speed; the feature matching includes: rule matching based on speed threshold, yaw rate threshold, attitude angle threshold, and adhesion coefficient range, or nearest working condition matching based on weighted Euclidean distance.

4. The method for constructing a modular tracked vehicle dynamics model according to claim 1, characterized in that, The equivalent vertical stiffness extraction process includes: Taking a single track unit and its equivalent vehicle body mass above it as the research object, and considering a single road wheel and its suspension system as a mass-spring-damping system, the force balance equation is established. The net suspension force on the equivalent vehicle body is calculated based on the force balance equation, and the ratio of the net suspension force to the static deformation of the suspension is extracted as the equivalent vertical stiffness.

5. The method for constructing a modular tracked vehicle dynamics model according to claim 1, characterized in that, The expression for the state space matrix is: in, This represents the six-degree-of-freedom state variables of the entire vehicle; Represents the vehicle state matrix; The output variable represents the longitudinal force, lateral force, and vertical force of the i-th track unit; Let r represent the input distribution matrix, where r is the total number of track unit modules.

6. A modular tracked vehicle distributed control method, applied to a tracked vehicle comprising multiple track unit modules and a vehicle communication network, characterized in that, The control method is based on the vehicle dynamics equations established by the dynamics model construction method according to any one of claims 1-5, and includes the following steps: Node configuration steps: Configure each track unit module as an independent distributed computing node, and equip each track unit module with an electronic control unit (ECU) with independent computing capabilities; State interaction steps: Each ECU performs a weakly coupled interaction between the track unit module and the vehicle state through the vehicle communication network, and obtains the global state variables of the vehicle and the state information of adjacent track unit modules in real time. Independent calculation steps: Each ECU calls the local state space equation of the track unit constructed based on the equivalent longitudinal stiffness, equivalent lateral stiffness and equivalent vertical stiffness, and uses the global state variables and the state information of adjacent track unit modules as boundary inputs to independently calculate the optimal control law of this node. The optimal control law includes the target value of track traction force. Drive execution steps: Each ECU generates a drive wheel motor torque command based on the track traction target value in the optimal control law, and independently drives the corresponding track unit module.

7. The modular tracked vehicle distributed control method according to claim 6, characterized in that, The weakly coupled interaction process between the track unit module and the overall vehicle status includes: Each ECU independently calculates the local forces and uses them as output variables. Send to the vehicle coordination node via the vehicle communication network; The update of the overall vehicle status depends only on the output variables uploaded to each track unit node. State-space matrix operations are performed, and each ECU independently solves the microscopic force problem during the track slippage process locally.

8. The distributed control method for modular tracked vehicles according to claim 6, characterized in that, The form of the local state-space equation of the track unit is: in, This is the state vector of this node module itself. This is the control input matrix for this node. Let be the road surface excitation vector. These are the state vectors of neighboring modules obtained through the network. These are the corresponding coefficient matrices; the elements of the coefficient matrices contain the equivalent stiffness updated based on the real-time slip velocity.

9. The distributed control method for modular tracked vehicles according to claim 6, characterized in that, The process of generating drive wheel motor torque commands includes: Establish rotational dynamic equations that include track traction, equivalent resistance of a single track, and overall equivalent rotational inertia of the drive wheel; The ECU substitutes the target value of the track traction force into the rotational dynamics equation, calculates the target driving torque of the motor in reverse, and sends it to the motor controller of the drive wheel.

10. An electronic device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction, which causes the processor to perform an operation corresponding to the modeling method as described in any one of claims 1-5 or the control method as described in any one of claims 6-9.

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