Dynamic matrix and graph theory model construction method of HMCVT

Abstract

The invention discloses a dynamic matrix and graph theory model construction method for an HMCVT. The dynamic matrix and graph theory model construction method comprises the following steps that S1, a layered topological graph of a hydraulic mechanical continuously variable transmission is established; s2, constructing an adjacent matrix of the layered topological graph as a feature matrix; s3, determining a transmission constraint condition and a structure constraint condition of the hydraulic mechanical continuously variable transmission; s4, constructing and simplifying a rotating speed matrix equation, performing isomorphic identification through the simplified rotating speed matrix equation, and finding out a graph theory model of the HMCVT with the same transmission mechanism; and S5, constructing a basic torque matrix equation to obtain torque state matrix equations under different connection modes, and reflecting the dynamic performance of the graph theory model through the rotating speed matrix equation and the torque state matrix equations. According to the method, the conversion of a computer programming language is facilitated, a powerful theoretical reference is provided for realizing structure digitization, the time for designing the HMCVT structure can be greatly saved, and the design complexity is reduced.

Description

Technical Field

[0001] The 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 a HMCVT. Background Art

[0002] In recent years, more and more scholars have begun to apply graph theory and other methods to the powertrain configuration and planetary array enumeration of hybrid vehicles. Based on graph theory, adjacency matrices are constructed to realize the digitization of the structural design process, and finally replace the manual design process with AI. For a large agricultural country like my country, with the process of agricultural modernization, mechanized equipment such as tractors will become the "new workers" of unmanned farms in the future. Therefore, it is urgent to realize the digitization of the structural design process of hydraulic mechanical continuously variable transmission (HMCVT).

[0003] The Chinese patent application number CN201510908381.8 discloses a method for establishing a planetary transmission group model based on graph theory. Combining the graph theory modeling method and the kinematic characteristics of planetary transmission, a graph theory model of a planetary gear group with relative speed significance is established. Based on the graph theory model, the engagement state of the brake or clutch is converted into a corresponding topological transformation. This technical solution is mainly aimed at the transmission system of the planetary gear without a hydraulic system, and cannot represent the special connection relationship between the hydraulic pump and the hydraulic motor. At the same time, the purpose of establishing the graph theory in this technical solution is to describe the shifting process, and it is impossible to construct the torque matrix equation and the speed matrix equation that reflect the dynamic performance.

[0004] The Chinese patent application number CN201610225418.1 discloses a method for selecting a planetary transmission scheme by determining the optimal match between structural parameters and the number of gears and establishing a multi-objective optimization model to analyze transmission performance. The analysis of the entire transmission scheme in this application is performed directly on the graph, making it difficult to digitize the process. At the same time, in the multi-objective optimization constraints, the number of clutches and planetary gear trains is restricted, and a transmission gear train with more than 5 planetary gears cannot be determined.

[0005] The existing graph theory models are mainly based on hybrid electric vehicles. Chongqing University in China published articles titled "Design of all-wheel-drive power-splithybrid configuration schemes based on hierarchical topology graph theory" and "Configuration optimization for improving fuel efficiency of power split hybrid powertrains with a single planetary gear" in "Energy" and "Applied Energy", respectively, and constructed graph theory models of two-wheel drive and four-wheel drive hybrid electric vehicles. However, since the model cannot represent the connection relationship between the hydraulic transmission system and the planetary gear, it is not suitable for the continuously variable transmission of the tractor. At the same time, it does not realize the expression of the constraint conditions in the form of a matrix, which is not conducive to the conversion of programming languages. The correlation between different matrices is not strong. Summary of the invention

[0006] The present invention aims to provide a method for constructing a dynamic matrix and graph theory model of HMCVT to solve the above problems.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for constructing a dynamic matrix and graph theory model of HMCVT includes the following steps:

[0009] S1. Establishing a hierarchical topology diagram of a hydraulic mechanical continuously variable transmission;

[0010] S2, constructing the adjacency matrix of the hierarchical topological graph as the feature matrix;

[0011] S3, determining the transmission constraints and structural constraints of the hydraulic mechanical continuously variable transmission;

[0012] S4, construct and simplify the speed matrix equation, perform isomorphism identification through the simplified speed matrix equation, and find out the graph theory model of the feasible configuration of the HMCVT with the same transmission mechanism;

[0013] 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 by the speed matrix equation and the torque state matrix equation.

[0014] Preferably, the S1 comprises the following steps:

[0015] The core components of the hydraulic mechanical continuously variable transmission are used as nodes of the hierarchical topology graph, and the core components include an engine (E), wheels (T), a hydraulic pump (P), a hydraulic motor (M), a sun gear (s), a planet carrier (c), a ring gear (r), and a frame (G);

[0016] The sun gear (s), the planet carrier (c), and the ring gear (r) constitute a planetary row, and the planetary row is used as the first layer of the hierarchical topology diagram, the engine (E), the wheel (T), the hydraulic pump (P), and the hydraulic motor (M) are used as the second layer of the hierarchical topology diagram, and the frame (G) is used as the third layer of the hierarchical topology diagram;

[0017] A single solid line is used to represent 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).

[0018] 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;

[0019] The submatrix formed by the elements at the intersection of rows E, T, P, and M in the feature matrix is ​​defined as connection matrix A0, and the submatrix formed by the elements at the intersection of rows E, T, P, M, columns s, c, and r in the feature matrix is ​​defined as connection matrix A1.

[0020] Preferably, the transmission constraints are as follows:

[0021] (1) One of the two nodes, the hydraulic pump (P) and the hydraulic motor (M), is connected to the planetary gear, 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).

[0022] (2) The engine (E) is connected to only one node in the planetary gear train;

[0023] (3) The wheel (T) is connected to only one node in the planetary gear train;

[0024] (4) The engine (E) and the hydraulic motor (M) cannot be connected to the same node of the planetary gear at the same time;

[0025] (5) For the connection between planetary rows, at most two nodes in one planetary row are connected to the same nodes in another planetary row;

[0026] The transmission constraints are reflected in the characteristic matrix as follows:

[0027] (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.

[0028] (2) The first row of the connection matrix A1 has only one non-zero element;

[0029] (3) The second row of the connection matrix A1 has only one non-zero element;

[0030] (4) For a matrix whose (E, P) element is 1, if (E, X i )=(M,X i ), then (E,X i )=(M,X i )≠1;

[0031] (5) For the submatrix composed of planetary row nodes in the characteristic matrix:

[0032]

[0033] 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, and when y is constant, a ≤ 2.

[0034] Preferably, the structural constraints are as follows:

[0035] (1) The connection between the components has no transmission significance;

[0036] (2) The engine must pass through the transmission system before it can be connected to the tractor wheels;

[0037] The structural constraints are reflected in the feature matrix as follows:

[0038] (1) The diagonal elements of the feature matrix are all 0;

[0039] (2) The elements at the positions of (E, T) and (T, E) are 0;

[0040] 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.

[0041] Preferably, S4 comprises the following steps:

[0042] S41, constructing a speed matrix equation according to the hierarchical topology diagram;

[0043] S42, simplify the speed matrix equation obtained in S41, and obtain the simplest speed matrix equation:

[0044] IN = 0;

[0045] Among them, I is the transmission ratio matrix, N is the speed matrix;

[0046] 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.

[0047] Preferably, the S42 comprises the following steps:

[0048] S421, setting all transmission ratios in the speed matrix equation to 1;

[0049] S422, performing matrix row transformation;

[0050] S423, if all the elements in the bth column of the transmission ratio matrix after the matrix row transformation are 0, then delete the bth column of the transmission ratio matrix and the bth row of the speed matrix;

[0051] 424. Delete the sun gear (s), planet carrier (c), and ring gear (r) of the first layer of the hierarchical 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.

[0052] Preferably, the graph theory models of the feasible configurations of the HMCVT obtained in S4 are 39, including:

[0053] 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;

[0054] 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.

[0055] Preferably, the basic torque matrix equation is:

[0056] J0w=C0T+FD0G:

[0057]

[0058] Among them, J0 is the basic moment of inertia matrix, C0 and D0 are constant matrices, and 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, 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 moment of inertia of the ring gear, is the angular acceleration of the ring gear, and r is the number of teeth in the ring gear.

[0059] Preferably, the torque state matrix equation is:

[0060] J1w=C1T+FD1G;

[0061] Among them, J1=BJ0, c1=BC0, D1=BD0, and B is the clutch state matrix.

[0062] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0063] 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;

[0064] 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 realized by computer, and the torque matrix equation has been standardized in this solution;

[0065] 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 design. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0067] Figure 1 A flow chart of a method for constructing a dynamic matrix and graph theory model of HMCVT according to an embodiment of the present invention;

[0068] Figure 2 A schematic diagram of a layered topology diagram according to an embodiment of the present invention;

[0069] Figure 3 Schematic diagram of a characteristic matrix of an embodiment of the present invention;

[0070] Figure 4 A schematic diagram of a speed matrix according to an embodiment of the present invention;

[0071] Figure 5Schematic diagram of isomorphism recognition process of two isomorphic graph theory models according to an embodiment of the present invention;

[0072] Figure 6 It is a schematic diagram of a graph theory model of a hydraulic mechanical segment of an output split flow type according to an embodiment of the present invention;

[0073] Figure 7 It is a schematic diagram of a pure mechanical segment graph theory model of an output split type according to an embodiment of the present invention;

[0074] Figure 8 It is a schematic diagram of a pure hydraulic section graph theory model of an output split type according to an embodiment of the present invention;

[0075] Fig. 9 A schematic diagram of a graph theory model of a hydraulic mechanical segment of an input split flow type according to an embodiment of the present invention;

[0076] Fig.10 A schematic diagram of a pure mechanical segment graph theory model of an input split type according to an embodiment of the present invention;

[0077] Fig.11 It is a schematic diagram of a pure hydraulic section graph theory model of an input split flow type according to an embodiment of the present invention;

[0078] Fig.12 A transmission diagram of the Dongfanghong LW4004 hydraulic mechanical continuously variable transmission according to an embodiment of the present invention;

[0079] Fig.13 This is a graph theory model of a hybrid vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0080] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings. The schematic implementation modes and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention. It should be noted that the present invention is already in the actual development and use stage.

[0081] 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:

[0082] S1. Establish a hierarchical topology diagram of the hydraulic mechanical continuously variable transmission (HMCVT).

[0083] Take a single planetary gear as an example. Figure 2As shown in the figure, the core components of the hydraulic mechanical continuously variable transmission are used as nodes of the hierarchical topology diagram, and 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 the planetary gear, and the planetary gear is used as the first layer of the 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 frame (G) is used as the third layer of the hierarchical topology diagram. A single solid line represents the 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), planet carrier (c) and ring gear (r). The hierarchical topology diagram can more clearly reflect the connection mode of different working sections of the HMCVT. At the same time, the construction of the HMCVT hierarchical topology diagram is an important basis for constructing the characteristic matrix, speed matrix and torque matrix.

[0084] S2. Construct the adjacency matrix of the hierarchical topological graph as the feature matrix.

[0085] 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 that it can be a gear pair connection or no connection. In this implementation, all the elements of the upper triangle of the feature matrix except the elements on the diagonal are arranged in sequence 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.

[0086] In order to better determine the graph theory model of the feasible configuration of HMCVT, in this embodiment, the submatrix composed of the elements at the intersection of rows E, T, P, and M in the feature matrix is ​​defined as the connection matrix A0, and the submatrix composed of the elements at the intersection of rows E, T, P, M, s, c, and r in the feature matrix 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.

[0087] S3. Determine the transmission constraints and structural constraints of the hydraulic mechanical continuously variable transmission.

[0088] According to the different ways of power splitting, HMCVT is divided into input split type and output split type. The difference in structure between the two is whether the planetary gear or pump-motor system is connected close to the input end or the output end. Among them, the output split type is a double input (E, M) single output (T) type for the planetary gear, and the input split type is a single input (E) double output (P, T).

[0089] In order to determine the HMCVT graph theory model, the transmission constraints are defined as follows:

[0090] (1) One of the two nodes, the hydraulic pump (P) and the hydraulic motor (M), is connected to the planetary gear, 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).

[0091] (2) The engine (E) is connected to only one node in the planetary gear train;

[0092] (3) The wheel (T) is connected to only one node in the planetary gear train;

[0093] (4) The engine (E) and the hydraulic motor (M) cannot be connected to the same node of the planetary gear at the same time;

[0094] (5) For the connection between planetary trains, at most two nodes in one planetary train are connected to the same nodes in another planetary train.

[0095] The transmission constraints are reflected in the characteristic matrix as follows:

[0096] (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.

[0097] (2) The first row of the connection matrix A1 has only one non-zero element;

[0098] (3) The second row of the connection matrix A1 has only one non-zero element;

[0099] (4) For a matrix whose (E, P) element is 1, if (E, X i )=(M,X i ), then (E,X i )=(M,X i )≠1;

[0100] (5) For the submatrix composed of planetary row nodes in the characteristic matrix:

[0101]

[0102] 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, and when y is constant, a ≤ 2.

[0103] At the same time, the structural constraints are defined as follows:

[0104] (1) The connection between the components has no transmission significance;

[0105] (2) The engine must pass through the transmission system before it can be connected to the tractor wheels;

[0106] The structural constraints are reflected in the feature matrix as follows:

[0107] (1) The diagonal elements of the feature matrix are all 0;

[0108] (2) The elements at the positions of (E, T) and (T, E) are 0;

[0109] 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. The basic configuration matrix is Figure 3 The matrix within the red frame.

[0110] S4, construct the speed matrix equation and simplify it, perform isomorphism identification through the simplified speed matrix equation, and find the graph theory model of the feasible configuration of HMCVT with the same transmission mechanism. The graph theory models 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 realize this process, it is necessary to construct the speed matrix equation first. It includes the following steps:

[0111] S41, construct the following according to the hierarchical topology diagram: Figure 4 The speed matrix equation shown in the figure, in which e is the displacement ratio of the hydraulic system, and its value is the ratio of the speed of the hydraulic motor to that of the hydraulic pump, that is:

[0112]

[0113] Among them, n M is the speed of the hydraulic motor, n P is the speed of the hydraulic pump.

[0114] The speed matrix equation

[0115] k is the characteristic parameter of the planetary gear, and its value is the ratio of the number of teeth of the ring gear and the number of teeth of the sun gear, that is:

[0116]

[0117] Among them, Z r is the number of teeth on the gear ring, Z s is the number of teeth on the sun gear.

[0118] From the properties of the planetary gear, it can be deduced that the speed relationship of the three elements of the planetary gear satisfies:

[0119] n s +kn r -(1+k)n c =0;

[0120] Among them, n s is the speed of the sun gear, n r is the speed of the ring gear, n c is the rotation speed of the planet carrier.

[0121] 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:

[0122] i 主从 n 从 -n 主 =0;

[0123] 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.

[0124] 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:

[0125]

[0126] 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 cT is 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.

[0127] This can be written in matrix form as:

[0128]

[0129] S42, simplify the speed matrix equation obtained in S41, and obtain the simplest speed matrix equation:

[0130] IN=0:

[0131] Among them, I is the transmission ratio matrix and N is the speed matrix.

[0132] Since the transmission ratio value does not affect the transmission relationship during the isomorphism identification process, in order to simplify the calculation, the following steps are included:

[0133] S421, set all transmission ratios i in the speed matrix equation to 1, such as Figure 5 As shown in the third row;

[0134] S422, performing matrix row transformation;

[0135] S423, if all the elements in the b-th column of the transmission ratio matrix I after the matrix row transformation are 0, then delete the b-th column of the transmission ratio matrix I and the b-th row of the speed matrix N;

[0136] 424. 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.

[0137] 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.

[0138] After the transmission constraints and structural constraints are screened, there are graph models that meet the constraints but have the same transmission mechanism. They are essentially the same graph model. Figure 5 As shown in the figure, the speed matrix equations of the two graph theory models are constructed and simplified. The 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.

[0139] Among them, there are 6 types of hydraulic mechanical segment graph theory models in the output split type; Figure 7 As shown, 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 split flow formula, Fig. 9 As shown in the figure, there are 6 types of graph theory models for hydraulic machinery segments; Fig.10 As shown, there are 9 pure mechanical segment graph theory models; Fig.11 As shown, there are 6 pure hydraulic segment graph theory models.

[0140] 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.

[0141] By combining the clutch and graph theory model, a complete HMCVT (hydraulic mechanical continuously variable transmission) powertrain configuration can be obtained, such as Fig.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 this working section are constructed.

[0142] According to the layered topology diagram and the relationship between torque and moment of inertia The torque equations of each node are obtained, where J is the moment of inertia, is the angular acceleration, f is the torque, and the torque equations are as follows:

[0143]

[0144] 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, 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 moment of inertia of the ring gear, is the angular acceleration of the ring gear, and r is the number of teeth in the ring gear.

[0145] The torque equations can be rewritten into matrix form as follows:

[0146]

[0147] Simplified:

[0148]

[0149] The above formula can be simplified as:

[0150] J0w=C0T+FD0G;

[0151]

[0152] Among them, J0 is the basic moment of inertia matrix, C0 and D0 are constant matrices;

[0153] Construct the clutch state matrix B:

[0154]

[0155] 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:

[0156] BJ0w=BC0T+FBD0G;

[0157] Right now:

[0158]

[0159] J1w=C1T+FD1G;

[0160] J1=BJ0, C1=BC0, D1=BD0;

[0161] like Fig.13 The figure shows a graph model of a two-wheel drive hybrid vehicle that has been published, where P is a planetary gear, S is a sun gear, H is a planet carrier, R is a large ring gear, E is an engine, EM1 and EM2 are motors, V is a vehicle wheel, and G is a vehicle frame. Fig.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 constraints into matrix transformations, which is not conducive to the subsequent programming of program languages. The present application converts all constraints into matrices for representation, and can use computing software such as MATLAB to assist in the design process. At the same time, in the planetary gear train, the rotation speed of the planetary gear does not affect the rotation speed of the sun gear, planet carrier, and ring gear, while the rotation speed relationship between the sun gear, planet 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.

[0162] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

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 hydraulic mechanical continuously variable transmission; S2, constructing the adjacency matrix of the hierarchical topological graph as the feature matrix; S3, determining the transmission constraints and structural constraints of the hydraulic mechanical continuously variable transmission; S4, construct and simplify the speed matrix equation, perform isomorphism identification through the simplified speed matrix equation, and find out the graph theory model of the feasible configuration of the HMCVT with the same transmission mechanism; 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 by 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: The S1 comprises the following steps: The core components of the hydraulic mechanical continuously variable transmission are used as nodes of the hierarchical topology graph, and the core components include an engine (E), wheels (T), a hydraulic pump (P), a hydraulic motor (M), a sun gear (s), a planet carrier (c), a ring gear (r), and a frame (G); The sun gear (s), the planet carrier (c), and the ring gear (r) constitute a planetary row, and the planetary row is used as the first layer of the hierarchical topology diagram, the engine (E), the wheel (T), the hydraulic pump (P), and the hydraulic motor (M) are used as the second layer of the hierarchical topology diagram, and the frame (G) is used as the third layer of the hierarchical topology diagram; A single solid line is used to represent 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), the number 0 represents no connection, and the number X represents either a gear pair connection or no connection; The submatrix formed by the elements at the intersection of rows E, T, P, and M in the feature matrix is ​​defined as connection matrix A0, and the submatrix formed by the elements at the intersection of rows E, T, P, M, columns s, c, and r in the feature matrix is ​​defined as 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, 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 rows, at most two nodes in one planetary row are connected to the same nodes in another planetary row; The transmission constraints are reflected in the characteristic matrix as follows: (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. (2) The first row of the connection matrix A1 has only one non-zero element; (3) The second row of the connection matrix A1 has only one non-zero element; (4) For a matrix whose (E, P) element is 1, if (E, X i )=(M,X i ), then (E,X i )=(M,X i )≠1; (5) For the submatrix composed of planetary row nodes in the characteristic matrix: 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, and when y is constant, a ≤ 2.

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 feature matrix are all 0; (2) The elements at the positions of (E, T) and (T, E) are 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 S4 comprises the following steps: S41, constructing a speed matrix equation according to the hierarchical topology diagram; S42, simplify the speed matrix equation obtained in S41, and obtain the simplest speed matrix equation: IN = 0; Among them, I is the transmission ratio matrix, N is the speed matrix; 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.

7. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 6, characterized in that: The S42 comprises the following steps: S421, setting all transmission ratios in the speed matrix equation to 1; S422, performing matrix row transformation; S423, if all the elements in the bth column of the transmission ratio matrix after the matrix row transformation are 0, then 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) of the first layer of the hierarchical 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.

8. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 7, 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.

9. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 8, characterized in that: The basic torque matrix equation is: J0w=C0T+FD0G; Among them, J0 is the basic moment of inertia matrix, C0 and D0 are constant matrices, and 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, 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 moment of inertia of the ring gear, is the angular acceleration of the ring gear, and r is the number of teeth in the ring gear.

10. The method for constructing a dynamic matrix and graph theory model of HMCVT according to claim 9, characterized in that: The torque state matrix equation is: J1w=C1T+FD1G; Among them, J1=BJ0, c1=BC0, D1=BD0, and B is the clutch state matrix.

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