A method for constructing dynamic matrix and graph theory model of HMCVT

Abstract

The present invention discloses a method for constructing a dynamic matrix and graph theory model of a hydraulic-mechanical continuously variable transmission (HMCVT), comprising the following steps: S1, establishing a hierarchical topological graph of a hydraulic-mechanical continuously variable transmission; S2, constructing an adjacency matrix of the hierarchical topological graph as a characteristic matrix; S3, determining transmission constraints and structural constraints of the hydraulic-mechanical continuously variable transmission; S4, constructing and simplifying a speed matrix equation, performing isomorphism identification through the simplified speed matrix equation, and finding a graph theory model of an HMCVT with the same transmission mechanism; S5, constructing a basic torque matrix equation, obtaining a torque state matrix equation under different connection modes, and reflecting the dynamic performance of the graph theory model through the speed matrix equation and the torque state matrix equation. The present invention facilitates the conversion of computer programming languages, provides a powerful theoretical reference for realizing structural digitization, and can greatly save the time of HMCVT structural design and reduce the complexity of the design.

Description

Technical Field

[0001] The present invention relates to the technical field of tractor hydraulic mechanical continuously variable transmission structure, and in particular to a method for constructing a dynamic matrix and graph theory model of an HMCVT. Background Art

[0002] In recent years, a growing number of researchers have begun applying graph theory and other methods to the enumeration of hybrid vehicle powertrain configurations and planetary gear sets. Using graph theory as a foundation, they construct adjacency matrices to digitize the structural design process, ultimately replacing manual design with AI. For a major agricultural nation like my country, with the modernization of agriculture, mechanized equipment such as tractors will become the "new workers" of future unmanned farms. Therefore, digitizing the structural design process for hydraulic mechanical continuously variable transmissions (HMCVTs) is imperative.

[0003] Chinese patent application number CN201510908381.8 discloses a graph-theory-based method for modeling a planetary transmission assembly. Combining graph-theory modeling methods with the kinematic characteristics of planetary transmissions, this method establishes a graph-theory model of a planetary gear train with relative speed. Based on this graph-theory model, the engagement state of the brake or clutch is converted into a corresponding topological transformation. This technical solution primarily targets planetary gear trains without hydraulic systems and cannot represent the specific connection between the hydraulic pump and hydraulic motor. Furthermore, while the graph theory is designed to describe the shifting process, it cannot construct torque and speed matrix equations that reflect dynamic performance.

[0004] Chinese patent application number CN201610225418.1 discloses a method for selecting a planetary transmission scheme. This method analyzes transmission performance by determining the optimal match between structural parameters and the number of gears and establishing a multi-objective optimization model. This application analyzes the entire transmission scheme directly on a graph, making it difficult to digitize the process. Furthermore, the multi-objective optimization constraints limit the number of clutches and planetary gear trains, making it impossible to select transmission trains with more than five planetary gears.

[0005] Existing graph theory models primarily focus on hybrid vehicles. Chongqing University in China published articles titled "Design of all-wheel-drive power-split hybrid configuration schemes based on hierarchical topology graph theory" and "Configuration optimization for improving fuel efficiency of powersplit hybrid powertrains with a single planetary gear" in Energy and Applied Energy, respectively, constructing graph theory models for two-wheel-drive and four-wheel-drive hybrid vehicles. However, because these models cannot represent the connection between the hydraulic transmission system and the planetary gear, they are not suitable for continuously variable transmissions in tractors. Furthermore, they do not represent the constraints in a matrix format, hindering conversion between programming languages. The correlation between different matrices is also weak. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a method for constructing a dynamic matrix and graph theory model of HMCVT.

[0007] This application discloses a method for constructing a dynamic matrix and graph theory model of HMCVT, comprising the following steps:

[0008] S1. Establishing a hierarchical topology diagram of a hydromechanical continuously variable transmission;

[0009] S2, constructing the adjacency matrix of the hierarchical topological graph as the feature matrix;

[0010] S3. Determine the transmission constraints and structural constraints of the hydromechanical continuously variable transmission;

[0011] S4. Construct and simplify the speed matrix equation, perform isomorphism identification through the simplified speed matrix equation, and find a graph theory model of the feasible configuration of the HMCVT with the same transmission mechanism;

[0012] S5. Construct a basic torque matrix equation, multiply the clutch state matrix on both ends of the basic torque matrix equation to the left, and obtain the torque state matrix equation under different connection modes. The dynamic performance of the graph theory model is reflected through the speed matrix equation and the torque state matrix equation.

[0013] Preferably, said S1 comprises the following steps:

[0014] The core components of the hydromechanical continuously variable transmission are used as nodes of the hierarchical topology graph. The core components include the engine (E), wheels (T), hydraulic pump (P), hydraulic motor (M), sun gear (s), planet carrier (c), ring gear (r), and frame (G).

[0015] The sun gear (s), planet carrier (c), and ring gear (r) constitute a planetary gear set, which is used as the first layer of a hierarchical topology diagram; the engine (E), wheels (T), hydraulic pump (P), and hydraulic motor (M) are used as the second layer of the hierarchical topology diagram; and the vehicle frame (G) is used as the third layer of the hierarchical topology diagram;

[0016] A single solid line represents a gear pair, a double solid line represents the connection between the hydraulic pump (P) and the hydraulic motor (M), and a dotted line represents the connection between the sun gear (s), the planet carrier (c), and the ring gear (r).

[0017] Preferably, in the characteristic matrix, the number 1 represents a gear pair, the number 2 represents the connection between the hydraulic pump (P) and the hydraulic motor (M), the number 3 represents the connection between the sun gear (s), the planet carrier (c), and the ring gear (r), the number 0 represents no connection, and the number X represents either a gear pair connection or no connection;

[0018] The feature matrix E H Line, T H Line, P L Column, M L The submatrix formed by the elements at the cross position of the columns is defined as the connection matrix A0, and the E H Line, T H Line, P H Line, M H Line, s L Column, c L Column, r L The submatrix formed by the elements at the intersection of the columns is defined as the connection matrix A1.

[0019] Preferably, the transmission constraints are as follows:

[0020] (1) One of the two nodes, the hydraulic pump (P) and the hydraulic motor (M), is connected to the planetary gear set, and the other is connected to the engine (E) or the wheel (T). The hydraulic pump (P) can only be connected to the engine (E), and the hydraulic motor (M) can only be connected to the wheel (T).

[0021] (2) The engine (E) is connected to only one node in the planetary gear train;

[0022] (3) The wheel (T) is connected to only one node in the planetary gear train;

[0023] (4) The engine (E) and the hydraulic motor (M) cannot be connected to the same node of the planetary gear at the same time;

[0024] (5) For the connection between planetary rows, at most two nodes in one planetary row can be connected to the same nodes in another planetary row;

[0025] The transmission constraints are reflected in the characteristic matrix as follows:

[0026] (1) There is only one non-zero element 1 in the connection matrix A0, and it can only appear on the matrix diagonal. There is only one non-zero element in the third row of the connection matrix A1;

[0027] (2) The first row of the connection matrix A1 has only one non-zero element;

[0028] (3) The second row of the connection matrix A1 has only one non-zero element;

[0029] (4) For (E H ,P L ) is a matrix with 1 elements, if (E H ,X i )=(M H ,X i ), then (E H ,X i )=(M H ,X i )≠1;

[0030] (5) For the submatrix composed of planetary row nodes in the characteristic matrix:

[0031]

[0032] Let (x,y), where x=1,2,…,n. For a with an initial value of 0, when y=i (i=0,1,…), if (x,y)=1, then a=a+1. When y is constant, a≤2.

[0033] Preferably, the structural constraints are as follows:

[0034] (1) The connection between the components themselves has no transmission significance;

[0035] (2) The engine must pass through the transmission system before it can be connected to the tractor wheels;

[0036] The structural constraints are reflected in the feature matrix as follows:

[0037] (1) The diagonal elements of the characteristic matrix are all 0;

[0038] (2)(E H ,T L ) and (TH ,E L ) is 0;

[0039] The fixed submatrix that does not change with the graph theory model is obtained by the structural constraints and is defined as the basic configuration matrix.

[0040] Preferably, said S4 comprises the following steps:

[0041] S41. Constructing a speed matrix equation according to the hierarchical topology diagram;

[0042] S42. Simplify the speed matrix equation obtained in S41 to obtain the simplest speed matrix equation:

[0043] IN=0;

[0044] Among them, I is the transmission ratio matrix, N is the speed matrix;

[0045] S43. Compare the simplest speed matrix equations obtained in S42. If the simplest speed matrix equations are the same, they are the same graph theory model.

[0046] Preferably, the S42 includes the following steps:

[0047] S421, setting all transmission ratios in the speed matrix equation to 1;

[0048] S422, performing matrix row transformation;

[0049] S423. If all elements in the bth column of the transmission ratio matrix after the matrix row transformation are 0, delete the bth column of the transmission ratio matrix and the bth row of the speed matrix;

[0050] S424. Delete the sun gear (s), planet carrier (c), and ring gear (r) of the first layer of the layered topology diagram, that is, delete the 5th, 6th, and 7th columns of the transmission ratio matrix and the 5th, 6th, and 7th rows of the speed matrix.

[0051] Preferably, there are 39 graph theory models of feasible configurations of the HMCVT obtained in S4, including:

[0052] In the output split type, there are 6 hydraulic-mechanical segment graph theory models, 6 pure mechanical segment graph theory models, and 6 pure hydraulic segment graph theory models;

[0053] Among the input split types, there are 6 hydraulic-mechanical segment graph theory models, 9 pure mechanical segment graph theory models, and 6 pure hydraulic segment graph theory models.

[0054] Preferably, the basic torque matrix equation is:

[0055] J0w=C0T+FD0G g ;

[0056]

[0057] Among them, J0 is the basic moment of inertia matrix, C0 and D0 are constant matrices, T E is the engine torque, is the engine angular acceleration, T T is the wheel torque, is the wheel angular acceleration, T P is the hydraulic pump torque, is the angular acceleration of the hydraulic pump, T M is the hydraulic motor torque, is the angular acceleration of the hydraulic motor, F is the force between the planetary gears, is the sun gear angular acceleration, Z S is the number of sun gear teeth, is the planet carrier angular acceleration, is the angular acceleration of the ring gear, Z r is the number of ring gear teeth.

[0058] Preferably, the torque state matrix equation is:

[0059] J1w=C1T+FD1G g ;

[0060] Among them, J1=BJ0, c1=BC0, D1=BD0, and B is the clutch state matrix.

[0061] Beneficial effects of the present invention:

[0062] (1) The entire process of determining the graph theory model of the present invention is implemented through matrices, which is conducive to converting computer programming languages.

[0063] (2) All steps of the present invention are matrixed, which can provide a powerful theoretical reference for realizing structural digitization. The matrix calculations involved can be implemented by computer, and the torque matrix equation has been standardized in this scheme.

[0064] (3) The present invention integrates different connection schemes through a clutch to form a complete HMCVT transmission, which can greatly save the time of HMCVT structural design and reduce the complexity of the design. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 Flowchart of a method for constructing a dynamic matrix and graph theory model of HMCVT according to an embodiment of the present invention;

[0066] Figure 2 A schematic diagram of a layered topology diagram according to an embodiment of the present invention;

[0067] Figure 3 Schematic diagram of a characteristic matrix according to an embodiment of the present invention;

[0068] Figure 4 Schematic diagram of a speed matrix according to an embodiment of the present invention;

[0069] Figure 5 Schematic diagram of the isomorphism identification process of two isomorphic graph theory models according to an embodiment of the present invention;

[0070] Figure 6 Schematic diagram of a graph theory model of a hydraulic mechanical segment with output splitting according to an embodiment of the present invention;

[0071] Figure 7 Schematic diagram of a purely mechanical segment graph theory model of an output split type according to an embodiment of the present invention;

[0072] Figure 8 Schematic diagram of a pure hydraulic section graph theory model of an output split type according to an embodiment of the present invention;

[0073] Figure 9 Schematic diagram of a graph theory model of a hydraulic mechanical segment with input splitting according to an embodiment of the present invention;

[0074] Figure 10 Schematic diagram of a purely mechanical segment graph theory model of an input split type according to an embodiment of the present invention;

[0075] Figure 11 Schematic diagram of a pure hydraulic section graph theory model of an input split type according to an embodiment of the present invention;

[0076] Figure 12 A simplified transmission diagram of the Dongfanghong LW4004 hydraulic mechanical continuously variable transmission according to an embodiment of the present invention;

[0077] Figure 13 This is a graph theory model of a hybrid vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0078] In order to make the objectives, technical solutions and advantages of this application more clear, the application is further described in detail below with reference to the accompanying drawings and examples.

[0079] The present application embodiment discloses a method for constructing a dynamic matrix and graph theory model of HMCVT, such as Figure 1 As shown, the following steps are included:

[0080] S1. Establish a hierarchical topology diagram of the hydraulic mechanical continuously variable transmission (HMCVT).

[0081] Take a single planetary gear as an example, Figure 2As shown, the core components of a hydromechanical continuously variable transmission (HMCVT) are used as nodes in a hierarchical topology diagram. These core components include the engine (E), wheels (T), hydraulic pump (P), hydraulic motor (M), sun gear (s), planetary carrier (c), ring gear (r), and vehicle frame (G). The sun gear (s), planetary carrier (c), and ring gear (r) form the planetary gear set, which serves as the first layer of the hierarchical topology diagram. The engine (E), wheels (T), hydraulic pump (P), and hydraulic motor (M) serve as the second layer, and the vehicle frame (G) serves as the third layer. Single solid lines represent gear pairs, double solid lines represent the connection between the hydraulic pump (P) and hydraulic motor (M), and dashed lines represent the connection between the sun gear (s), planetary carrier (c), and ring gear (r). This hierarchical topology diagram clearly illustrates the connections between the different operating sections of the HMCVT. Furthermore, constructing the HMCVT hierarchical topology diagram is an important foundation for constructing the characteristic matrix, speed matrix, and torque matrix.

[0082] S2. Construct the adjacency matrix of the hierarchical topological graph as the feature matrix.

[0083] like Figure 3 As shown, each column of the feature matrix represents (E, T, P, M, s, c, r) and each row represents (E, T, P, M, s, c, r). Each position in the matrix corresponds to the connection status of two nodes. For example, the element at the position (1, 2) represents the connection between the engine (E) and the wheel (T). In the feature matrix, the number 1 represents the gear pair, the number 2 represents the connection between the hydraulic pump (P) and the hydraulic motor (M), the number 3 represents the connection between the sun gear (s), the planetary carrier (c), and the ring gear (r), the number 0 represents no connection, and X represents either a gear pair connection or no connection. In this implementation, all the elements of the upper triangle of the feature matrix excluding the elements on the diagonal are arranged in order to obtain a string of codes, which represent the unique feature codes of different graph theory models, for example Figure 3 The characteristic code is 0XXXXXXXXXX2XXXXXX303. So a total of 2 16 A graph theory model.

[0084] In order to better determine the graph theory model of the feasible configuration of HMCVT, in this embodiment, the E H Line, T H Line, P L Column, M L The submatrix formed by the elements at the cross position of the columns is defined as the connection matrix A0, and the E H Line, T H Line, P H Line, M H Line, s L Column, c L Column, r LThe submatrix formed by the elements at the column intersection position is defined as the connection matrix A1. The connection matrix A0 and the connection matrix A1 are Figure 3 The matrix within the medium blue wireframe.

[0085] S3. Determine the transmission constraints and structural constraints of the hydraulic mechanical continuously variable transmission.

[0086] HMCVTs are categorized as input-split and output-split types based on the power distribution method. The structural difference between the two types lies in whether the planetary gear or pump-motor system is connected closer to the input or output. For planetary gears, the output-split type has dual inputs (E, M) and a single output (T), while the input-split type has a single input (E) and dual outputs (P, T).

[0087] In order to determine the HMCVT graph theory model, the transmission constraints are defined as follows:

[0088] (1) One of the two nodes, the hydraulic pump (P) and the hydraulic motor (M), is connected to the planetary gear set, and the other is connected to the engine (E) or the wheel (T). The hydraulic pump (P) can only be connected to the engine (E), and the hydraulic motor (M) can only be connected to the wheel (T).

[0089] (2) The engine (E) is connected to only one node in the planetary gear train;

[0090] (3) The wheel (T) is connected to only one node in the planetary gear train;

[0091] (4) The engine (E) and the hydraulic motor (M) cannot be connected to the same node of the planetary gear at the same time;

[0092] (5) For the connection between planetary trains, at most two nodes in one planetary train can be connected to the same nodes in another planetary train.

[0093] The transmission constraints are reflected in the characteristic matrix as follows:

[0094] (1) There is only one non-zero element 1 in the connection matrix A0, and it can only appear on the matrix diagonal. There is only one non-zero element in the third row of the connection matrix A1;

[0095] (2) The first row of the connection matrix A1 has only one non-zero element;

[0096] (3) The second row of the connection matrix A1 has only one non-zero element;

[0097] (4) For (E H ,P L ) is a matrix with 1 elements, if (E H ,X i )=(M H ,Xi ), then (E H ,X i )=(M H ,X i )≠1;

[0098] (5) For the submatrix composed of planetary row nodes in the characteristic matrix:

[0099]

[0100] Let (x,y), where x=1,2,…,n. For a with an initial value of 0, when y=i (i=0,1,…), if (x,y)=1, then a=a+1. When y is constant, a≤2.

[0101] At the same time, the structural constraints are defined as follows:

[0102] (1) The connection between the components themselves has no transmission significance;

[0103] (2) The engine must pass through the transmission system before it can be connected to the tractor wheels;

[0104] The structural constraints are reflected in the feature matrix as follows:

[0105] (1) The diagonal elements of the characteristic matrix are all 0;

[0106] (2)(E H ,T L ) and (T H ,E L ) is 0;

[0107] The fixed submatrix that does not change with the graph theory model is obtained from the structural constraints and is defined as the basic configuration matrix. The basic configuration matrix is Figure 3 The matrix within the red frame.

[0108] S4. Construct and simplify the speed matrix equation, and perform isomorphism identification through the simplified speed matrix equation to find the graph theory model of the feasible configuration of the HMCVT with the same transmission mechanism. The graph theory models that have been screened by the two constraints in S3 can be used for transmissions, but there are still graph theory models that can be replaced with each other, that is, there are graph theory models with the same transmission mechanism. In order to find the graph theory models with the same transmission mechanism, the isomorphism identification process is added. In order to achieve this process, it is necessary to first construct the speed matrix equation. It includes the following steps:

[0109] S41, construct the following according to the layered topology diagram: Figure 4 The speed matrix equation shown in the figure is: e is the displacement ratio of the hydraulic system, which is the ratio of the speed of the hydraulic motor to the speed of the hydraulic pump, that is:

[0110]

[0111] Among them, n M is the speed of the hydraulic motor, n P is the speed of the hydraulic pump.

[0112] In the speed matrix equation

[0113] k is the characteristic parameter of the planetary gear, and its value is the ratio of the number of teeth of the ring gear to that of the sun gear, that is:

[0114]

[0115] Among them, Z r is the number of teeth on the ring gear, Z s is the number of teeth on the sun gear.

[0116] From the properties of the planetary gear, it can be deduced that the speed relationship of the three elements of the planetary gear satisfies:

[0117] n s +kn r -(1+k)n c =0;

[0118] Among them, n s is the speed of the sun gear, n r is the speed of the ring gear, n c is the rotational speed of the planet carrier.

[0119] The transmission ratio in a gear transmission is equal to the ratio of the speed of the driving wheel to the speed of the driven wheel:

[0120] i 主从 n 从 -n 主 =0;

[0121] Among them, i 主从 is the transmission ratio in the gear transmission, n 主 is the driving wheel speed, n 从 is the driven wheel speed.

[0122] like Figure 5 The following is a schematic diagram of the isomorphism recognition process of two isomorphic graph theory models. Figure 5 Taking the left topology diagram in the first row as an example, we can get the speed equation group as follows:

[0123]

[0124] Among them, i ES is the gear ratio between node E and node s, n E is the engine speed, n s is the sun gear speed, i cTis the gear ratio between nodes c and T, n c is the speed of the planet carrier, n T is the wheel speed, i EP is the gear ratio between node E and node P, n P is the speed of the hydraulic pump, n M is the speed of the hydraulic motor, n r is the speed of the ring gear, i Mr is the gear ratio between node M and node r, e is the displacement ratio of the hydraulic motor system, and k is the characteristic parameter of the planetary gear train.

[0125] Written in matrix form:

[0126]

[0127] S42. Simplify the speed matrix equation obtained in S41 to obtain the simplest speed matrix equation:

[0128] IN=0;

[0129] Among them, I is the transmission ratio matrix and N is the speed matrix.

[0130] Since the transmission ratio does not affect the transmission relationship during the isomorphism identification process, the following steps are included to simplify the calculation:

[0131] S421. Set all transmission ratios i in the speed matrix equation to 1, such as Figure 5 As shown in the third row;

[0132] S422, performing matrix row transformation;

[0133] S423. If all elements in the bth column of the transmission ratio matrix I after the matrix row transformation are 0, delete the bth column of the transmission ratio matrix I and the bth row of the speed matrix N;

[0134] S424. To facilitate comparison, the sun gear (s), planet carrier (c), and ring gear (r) of the first layer of the hierarchical topology diagram are uniformly deleted in isomorphism identification, that is, the 5th, 6th, and 7th columns of the transmission ratio matrix I and the 5th, 6th, and 7th rows of the speed matrix N are deleted.

[0135] S43. Compare the simplest speed matrix equations obtained in S42. If the simplest speed matrix equations are the same, they are the same graph theory model.

[0136] After screening the transmission constraints and structural constraints, there are graph models that meet the constraints but have the same transmission mechanism. They are essentially the same graph model. Figure 5The speed matrix equations of the two graph theory models are constructed and simplified. Graph theory models with the same transmission mechanism have the same simplest speed matrix equation. Through two constraints and isomorphism identification, 39 graph theory models of feasible configurations of HMCVT are finally obtained.

[0137] Among them, there are 6 types of hydraulic mechanical segment graph theory models in the output split type; Figure 7 As shown in the figure, there are 6 pure mechanical segment graph theory models; Figure 8 As shown in Figure 1, there are 6 pure hydraulic segment graph theory models. In the input flow splitting formula, Figure 9 As shown in Figure 1, there are 6 graph theory models of hydraulic machinery segments; Figure 10 As shown in Figure 2, there are 9 pure mechanical segment graph theory models; Figure 11 As shown, there are 6 pure hydraulic segment graph theory models.

[0138] S5. Construct a basic torque matrix, and multiply the clutch state matrix on both ends of the basic torque matrix to obtain the torque matrix equations under different connection modes.

[0139] By combining the clutch and graph theory model, a complete HMCVT (hydraulic mechanical continuously variable transmission) powertrain configuration can be obtained, such as Figure 12 The figure shows the Dongfanghong LW4004 hydraulic mechanical continuously variable transmission. The output split hydraulic mechanical section ( Figure 6 Taking the second row (left figure) as an example, the speed matrix equation and torque matrix equation reflecting the dynamic performance of the working section are constructed.

[0140] According to the relationship between the layered topology diagram and torque and moment of inertia The torque equations of each node are obtained, where J is the moment of inertia, is the angular acceleration, T is the torque, and the torque equations are as follows:

[0141]

[0142] Among them, J E is the engine moment of inertia, T E is the engine torque, is the engine angular acceleration, J T is the wheel moment of inertia, T T is the wheel torque, is the wheel angular acceleration, J P is the moment of inertia of the hydraulic pump, T P is the hydraulic pump torque, is the angular acceleration of the hydraulic pump, J M is the moment of inertia of the hydraulic motor, T M is the hydraulic motor torque, is the angular acceleration of the hydraulic motor, F is the force between the planetary gears, J s is the sun gear moment of inertia, is the sun gear angular acceleration, Z S is the number of sun gear teeth, J c is the planet carrier moment of inertia, is the planet carrier angular acceleration, J r is the ring gear moment of inertia, is the angular acceleration of the ring gear, Z r is the number of ring gear teeth.

[0143] The torque equations can be rewritten into matrix form as follows:

[0144]

[0145] Simplified:

[0146]

[0147] The above formula can be simplified as follows:

[0148] J0w=C0T+FD0G g ;

[0149]

[0150] Among them, J0 is the basic moment of inertia matrix, C0 and D0 are constant matrices;

[0151] Construct the clutch state matrix B:

[0152]

[0153] Multiplying the clutch matrix on both sides of the simplified torque equation to obtain the torque state matrix of the output split hydraulic mechanical short circuit is:

[0154] BJ0w=BC0T+FBD0G g ;

[0155] Right now:

[0156]

[0157] J1w=C1T+FD1G g ;

[0158] J1=BJ0, C1=BC0, D1=BD0;

[0159] like Figure 13The figure shows a graph theory model of a two-wheel drive hybrid vehicle that has been published, where P is the planetary gear, S is the sun gear, H is the planet carrier, R is the ring gear, E is the engine, EM1 and EM2 are motors, V is the vehicle wheel, and G is the frame. Figure 13 Compared with the method, the present application is more targeted and is mainly used for hydraulic mechanical continuously variable transmissions on tractors, while the existing methods mainly build graph theory models based on hybrid vehicles, and fail to convert the constraints into matrix transformations, which is not conducive to the subsequent programming of program languages. The present application converts all the constraints into matrices, and can use computing software such as MATLAB to assist in completing the design process. At the same time, in the planetary gear system, the rotational speed of the planetary gear does not affect the rotational speed of the sun gear, planetary carrier, and ring gear, while the rotational speed relationship between the sun gear, planetary carrier, and ring gear affects each other, so the planetary gear can be ignored in the construction of the graph theory model. Therefore, the graph theory model of the present application is not only highly targeted, but also concise and clear.

[0160] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for constructing a dynamic matrix and graph theory model of HMCVT, characterized in that: The following steps are involved: S1. Establishing a hierarchical topology diagram of a hydromechanical continuously variable transmission; S2, constructing the adjacency matrix of the hierarchical topological graph as the feature matrix; S3. Determine the transmission constraints and structural constraints of the hydromechanical continuously variable transmission; S4. Construct and simplify the speed matrix equation, perform isomorphism identification through the simplified speed matrix equation, and find a graph theory model of the feasible configuration of the HMCVT with the same transmission mechanism; S4 includes the following steps: S41. Constructing a speed matrix equation according to the hierarchical topology diagram; S42. Simplify the speed matrix equation obtained in S41 to obtain the simplest speed matrix equation: IN=0; Among them, I is the transmission ratio matrix, N is the speed matrix; S42 includes the following steps: S421, setting all transmission ratios in the speed matrix equation to 1; S422, performing matrix row transformation; S423. If all elements in the bth column of the transmission ratio matrix after the matrix row transformation are 0, delete the bth column of the transmission ratio matrix and the bth row of the speed matrix; S424, deleting the sun gear (s), planet carrier (c), and ring gear (r) in the first layer of the layered topology diagram, that is, deleting the 5th, 6th, and 7th columns of the transmission ratio matrix and the 5th, 6th, and 7th rows of the speed matrix; S43. Compare the simplest speed matrix equations obtained in S42. If the simplest speed matrix equations are the same, then they are the same graph theory model; S5. Construct a basic torque matrix equation, multiply the clutch state matrix on both ends of the basic torque matrix equation to the left, and obtain the torque state matrix equation under different connection modes. The dynamic performance of the graph theory model is reflected through the speed matrix equation and the torque state matrix equation.

2. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 1, characterized in that: Said S1 comprises the following steps: The core components of the hydromechanical continuously variable transmission are used as nodes of the hierarchical topology graph. The core components include the engine (E), wheels (T), hydraulic pump (P), hydraulic motor (M), sun gear (s), planet carrier (c), ring gear (r), and frame (G). The sun gear (s), planet carrier (c), and ring gear (r) constitute a planetary gear set, which is used as the first layer of a hierarchical topology diagram; the engine (E), wheels (T), hydraulic pump (P), and hydraulic motor (M) are used as the second layer of the hierarchical topology diagram; and the vehicle frame (G) is used as the third layer of the hierarchical topology diagram; A single solid line represents a gear pair, a double solid line represents the connection between the hydraulic pump (P) and the hydraulic motor (M), and a dotted line represents the connection between the sun gear (s), the planet carrier (c), and the ring gear (r).

3. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 2, characterized in that: In the characteristic matrix, the number 1 represents a gear pair, the number 2 represents the connection between the hydraulic pump (P) and the hydraulic motor (M), the number 3 represents the connection between the sun gear (s), the planet carrier (c), and the ring gear (r), and the number 0 represents no connection. The element X in the characteristic matrix represents either a gear pair connection or no connection. The feature matrix E H Line, T H Line, P L Column, M L The submatrix formed by the elements at the cross position of the columns is defined as the connection matrix A0, and the E H Line, T H Line, P H Line, M H Line, s L Column, c L Column, r L The submatrix formed by the elements at the intersection of the columns is defined as the connection matrix A1.

4. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 3, characterized in that: The transmission constraints are as follows: (1) One of the two nodes, the hydraulic pump (P) and the hydraulic motor (M), is connected to the planetary gear set, and the other is connected to the engine (E) or the wheel (T). The hydraulic pump (P) can only be connected to the engine (E), and the hydraulic motor (M) can only be connected to the wheel (T). (2) The engine (E) is connected to only one node in the planetary gear train; (3) The wheel (T) is connected to only one node in the planetary gear train; (4) The engine (E) and the hydraulic motor (M) cannot be connected to the same node of the planetary gear at the same time; (5) For the connection between planetary trains, at most two nodes in one planetary train can be connected to the same nodes in another planetary train.

5. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 4, characterized in that: The structural constraints are as follows: (1) The connection between the components has no transmission significance; (2) The engine must pass through the transmission system before it can be connected to the tractor wheels; The structural constraints are reflected in the feature matrix as follows: (1) The diagonal elements of the characteristic matrix are all 0; (2)(E H ,T L ) and (T H ,E L ) is 0; The fixed submatrix that does not change with the graph theory model is obtained by the structural constraints and is defined as the basic configuration matrix.

6. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 5, characterized in that: The graph theory models of feasible configurations of HMCVT obtained by S4 are 39, including: In the output split type, there are 6 hydraulic-mechanical segment graph theory models, 6 pure mechanical segment graph theory models, and 6 pure hydraulic segment graph theory models; Among the input split types, there are 6 hydraulic-mechanical segment graph theory models, 9 pure mechanical segment graph theory models, and 6 pure hydraulic segment graph theory models.

7. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 6, characterized in that: The basic torque matrix equation is: J0w=C0T+FD0G g ; Among them, J0 is the basic moment of inertia matrix, C0 and D0 are constant matrices, T E is the engine torque, is the engine angular acceleration, T T is the wheel torque, is the wheel angular acceleration, T P is the hydraulic pump torque, is the angular acceleration of the hydraulic pump, T M is the hydraulic motor torque, is the angular acceleration of the hydraulic motor, F is the force between the planetary gears, is the sun gear angular acceleration, Z S is the number of sun gear teeth, is the planet carrier angular acceleration, is the angular acceleration of the ring gear, Z r is the number of ring gear teeth.

8. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 7, characterized in that: The torque state matrix equation is: J1w=C1T+FD1G g ; Among them, J1=BJ0, C1=BC0, D1=BD0, and B is the clutch state matrix.

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