Hybrid electric vehicle following control method and device based on Nash equilibrium solution
Through the hybrid vehicle following control method based on Nash equilibrium solution, the problem of difficulty in achieving a balance between power and economy of hybrid vehicles in following scenarios is solved, and more efficient driving control is achieved.
Patent Information
- Application Number
- CN202411313960.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-01-21
AI Technical Summary
It is difficult for hybrid vehicles to achieve balanced control of power and economy in urban car-following scenarios, affecting the driving efficiency of vehicles.
A hybrid vehicle following control method based on the Nash equilibrium solution is adopted to determine the engine and motor parameters by establishing a vehicle speed model, calculating the optimal following distance, constructing dynamic and economic indicators, and solving the Nash equilibrium through the game profit matrix. Power distribution.
It achieves balanced control of power and economic indicators in car-following scenarios, improves the driving efficiency of the vehicle, and can quickly obtain the instantaneous Nash equilibrium optimal solution.
Smart Images
Figure CN119329521A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of vehicle spacing control, and in particular to a hybrid vehicle following control method and device based on Nash equilibrium solution. Background Art
[0002] Hybrid vehicles have multiple power sources and can adopt different energy distribution methods to cope with various road environments to improve the vehicle's driving efficiency. Hybrid vehicles have balanced operation problems in urban following scenarios. Generally speaking, hybrid vehicles mainly need to solve the problem of balancing power and economy in following scenarios. The power index is mainly reflected in the vehicle's instantaneous speed and following distance, and these parameters directly affect the energy distribution decision of the hybrid vehicle and affect the economy index. Therefore, it is necessary to find a control strategy that can balance the power and economy indicators of hybrid vehicles in following scenarios. Summary of the invention
[0003] In view of the defects of the above-mentioned prior art, the present invention provides a hybrid vehicle following control method based on Nash equilibrium solution, which solves the problem of balanced selection of power and economy indicators of hybrid vehicles in following scenarios. Another object of the present invention is to provide a hybrid vehicle following control device based on Nash equilibrium solution.
[0004] The technical solution of the present invention is as follows: A hybrid electric vehicle following control method based on Nash equilibrium solution, comprising:
[0005] The speed model of the controlled vehicle is established based on the longitudinal dynamics model of the hybrid vehicle;
[0006] Calculate the upper limit and lower limit of the optimal following distance according to the vehicle speed obtained from the vehicle speed model;
[0007] The dynamic index is constructed by the upper limit of the optimal following distance and the lower limit of the optimal following distance;
[0008] Establishing the economic model of the controlled vehicle based on the instantaneous fuel consumption of the engine and the instantaneous equivalent fuel consumption of electric energy;
[0009] Construct economic indicators based on economic models;
[0010] The power performance index and the economic performance index are standardized to obtain a standard power performance index and a standard economic performance index, wherein the power performance index and the economic performance index are both related to the engine power and the motor power;
[0011] Constructing a game payoff matrix based on several feasible output powers of the engine and several feasible output powers of the motor, wherein each element of the game payoff matrix is a standard power performance index and a standard economic performance index under a specific feasible output power of the engine and a specific feasible output power of the motor;
[0012] The game payoff matrix is solved for Nash equilibrium to obtain converged engine feasible output power and motor feasible output power for controlling the controlled vehicle.
[0013] Furthermore, the Nash equilibrium solution for the game payoff matrix includes the following steps:
[0014] S1, randomly select a feasible output power of an engine;
[0015] S2. Calculate the motor output power that minimizes the standardized dynamic performance index based on the selected engine feasible output power;
[0016] S3, based on the motor output power obtained in S2, solve the engine output power that minimizes the standardized economic index;
[0017] Repeat the process of S2 and S3 for iteration until the final output motor output power and engine output power converge. If the final result does not converge, return to S1 and re-select a feasible output power of the engine for iteration.
[0018] Furthermore, the dynamic index is
[0019]
[0020] in, is the upper limit of the optimal following distance, is the lower limit of the optimal following distance, α is the adjustment coefficient, and L(k) is the current following distance.
[0021] Further, in v h (k) is the vehicle speed determined by the vehicle speed model.
[0022] Furthermore, the value of α is 0.6 to 0.7.
[0023] Furthermore, the vehicle speed model is
[0024]
[0025] Among them, P e is the engine output power; P m is the motor output power; r is the tire radius; Fr = mgf cosθ is the rolling resistance; is air resistance; F g =mg sinθ is the acceleration resistance; m is the curb weight of the controlled vehicle; g is the acceleration of gravity; f is the rolling resistance coefficient; C d is the air resistance coefficient of the controlled vehicle; ρ is the air density; A is the windward area of the controlled vehicle; v h is the speed of the controlled vehicle; θ is the road slope; δ is the rotational mass conversion coefficient of the controlled vehicle.
[0026] Furthermore, the economic index is
[0027]
[0028] Among them, P e is the engine output power; η e is the engine efficiency; H f is the calorific value of fuel oil; P m Output power for the motor;
[0029] η m is the motor efficiency; η b is the battery efficiency; s is the equivalent factor.
[0030] Furthermore, the standardization process is performed according to the formula
[0031]
[0032] where X′ is the standardized data, X is the original indicator data, and X min is the minimum value among the indicators, X max is the maximum value among the indicators.
[0033] The present invention also provides a hybrid electric vehicle following control device based on Nash equilibrium solution, comprising:
[0034] Dynamic model module: used to establish the speed model of the controlled vehicle based on the longitudinal dynamic model of the hybrid vehicle;
[0035] Dynamic index calculation module: used to calculate the upper limit and lower limit of the optimal following distance according to the vehicle speed obtained by the vehicle speed model, and construct the dynamic index by the upper limit and lower limit of the optimal following distance;
[0036] Economic model module: used to establish the economic model of the controlled vehicle based on the instantaneous fuel consumption of the engine and the instantaneous equivalent fuel consumption of electric energy;
[0037] Economic index calculation module: used to construct economic indexes based on economic models;
[0038] A standardization module: used for standardizing the power performance index and the economic performance index to obtain a standard power performance index and a standard economic performance index, wherein the power performance index and the economic performance index are both related to the engine power and the motor power;
[0039] And, a Nash equilibrium solving module: used to construct a game benefit matrix based on several feasible output powers of the engine and several feasible output powers of the motor, each element of the game benefit matrix is a standard dynamic index and a standard economic index under a specific engine feasible output power and a specific motor feasible output power; performing Nash equilibrium solving on the game benefit matrix to obtain converged engine feasible output power and motor feasible output power for controlling the controlled vehicle.
[0040] Furthermore, the Nash equilibrium solving module includes:
[0041] Initial module: randomly select a feasible output power of an engine;
[0042] Iteration module: based on the selected feasible output power of the engine, the motor output power that minimizes the standardized dynamic performance index is solved; based on the obtained motor output power, the engine output power that minimizes the standardized economic performance index is solved;
[0043] And, control output module: repeatedly call the iteration module process to iterate until the final output motor output power and engine output power converge. If the final result does not converge, call the initial module to re-select a feasible output power of the engine for iteration.
[0044] Compared with the prior art, the advantages of the technical solution provided by the present invention are:
[0045] The present invention completes the power distribution between the engine and the motor by balancing the dynamic index and the economic index, completes the vehicle speed determination and energy management distribution, effectively handles the vehicle operation control with multiple variables and multiple constraints in the following vehicle scenario, and quickly obtains the instantaneous Nash equilibrium optimal solution. BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Figure 1 Schematic diagram of the hybrid vehicle following control method based on Nash equilibrium solution. DETAILED DESCRIPTION
[0047] The present invention is further described below in conjunction with examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading this description, various equivalent modifications to this description by those skilled in the art fall within the scope defined by the claims attached to this application.
[0048] Please combine Figure 1As shown, the hybrid vehicle following control method based on the Nash equilibrium solution of the embodiment of the present invention includes the following implementation steps:
[0049] Step 1: Establish the vehicle longitudinal dynamics model and the controlled vehicle speed model.
[0050] According to the vehicle dynamics theory, the longitudinal dynamics model of a hybrid vehicle can be expressed as:
[0051] F w =F r +F c +F g +F a (1) In the formula,
[0052]
[0053] F r is the rolling resistance; F c is air resistance; F g is the climbing resistance; F a is the acceleration resistance; m is the curb weight of the controlled vehicle; g is the acceleration of gravity; f is the rolling resistance coefficient; C d is the air resistance coefficient of the controlled vehicle; ρ is the air density; A is the windward area of the controlled vehicle; v h is the speed of the controlled vehicle; θ is the road slope; δ is the rotational mass conversion coefficient of the controlled vehicle.
[0054] The output power of a hybrid vehicle can be basically divided into engine power and motor power. Combined with formula (1), the speed model of the controlled vehicle can be expressed as
[0055]
[0056] Where P e is the engine output power; P m is the motor output power; r is the tire radius.
[0057] Step 2: Determine the dynamic indicators.
[0058] The dynamic performance index of hybrid vehicles requires that the controlled vehicle maintain a safe distance from the vehicle in front. First, the minimum following distance and the maximum following distance are determined, which can be expressed as:
[0059]
[0060] In the formula, k represents the time. The upper and lower limits of the optimal following distance can be expressed as
[0061]
[0062] In the formula, is the upper limit of the optimal following distance, is the lower limit of the optimal following distance, and α is the adjustment coefficient, which can generally be 0.6 to 0.7. Based on the optimal following distance, the dynamic performance index of the hybrid vehicle is:
[0063]
[0064] Where L(k) is the current following distance.
[0065] Step 3: Establish a hybrid vehicle economic model.
[0066] The present invention uses the equivalent fuel consumption minimum strategy (ECMS) as the energy management strategy for hybrid electric vehicles. For the energy management strategy based on ECMS, the economic model of hybrid electric vehicles is:
[0067]
[0068] In the formula, is the instantaneous fuel consumption of the engine; is the instantaneous equivalent fuel consumption of electric energy; is the instantaneous equivalent fuel consumption. The instantaneous fuel consumption of the engine is calculated by the following formula:
[0069]
[0070] Where P e is the engine output power; η e is the engine efficiency; H f is the calorific value of fuel oil. The instantaneous equivalent fuel oil consumption of electric energy is calculated by the following formula:
[0071]
[0072] Where P m is the motor output power, η m is the motor efficiency, η b is the battery efficiency and s is the equivalent factor.
[0073] Step 4: Determine economic indicators.
[0074] The instantaneous equivalent fuel consumption of hybrid vehicles under ECMS can directly reflect the economic performance of the vehicle. The economic performance index is defined as:
[0075]
[0076] Step 5: Standardize performance indicators.
[0077] The normalization formula is:
[0078]
[0079] The dynamic index and economic index range are standardized by formula (12), where X′ is the standardized data, X is the original index data, and X min is the minimum value among the indicators, X max is the maximum value among the indicators. After standardization, the standardized dynamic index, standardized economic index and engine output power P are obtained. e And the motor output power P m The relationship is as follows:
[0080] J t ' rack =f 1 (P e ,P m )
[0081] J e ' co =f 2 (P e ,P m )
[0082] In the formula, J t ' rack is the standardized dynamic index, J e ' co It is a standardized economic indicator.
[0083] Step 6: Solve the Nash equilibrium.
[0084] According to the output power of the engine and the motor at a certain moment, the game payoff matrix of the hybrid vehicle can be formulated, as shown in Table 1. e1 To P ei is the i-th feasible output power of the engine, P m1 To P mj is the j possible output power of the motor.
[0085] Table 1 Game payoff matrix
[0086]
[0087] The specific steps for solving Nash equilibrium are as follows:
[0088] Step 6.1: Randomly select the initial engine output power
[0089] Step 6.2: Based on engine output power Find the motor output power that minimizes the standardized dynamic performance index
[0090] Step 6.3: Based on the result obtained in step 6.2 Find the engine output power that minimizes the standardized economic index
[0091] Repeat steps 6.2 and 6.3 to iterate until the final output is Convergence, if the final result does not converge, reselect the initial engine output power Iterate. The final calculated That is the hybrid vehicle following control solution at a certain moment.
[0092] Another embodiment of the present invention is a device for implementing the aforementioned hybrid vehicle following control method based on Nash equilibrium solution, which includes multiple modules. Specifically:
[0093] Dynamic model module: used to establish the speed model of the controlled vehicle based on the longitudinal dynamic model of the hybrid vehicle. The speed model is
[0094]
[0095] Dynamic index calculation module: used to calculate the upper limit of the optimal following distance based on the vehicle speed obtained from the vehicle speed model and the optimal following distance lower limit The dynamics index is constructed by the optimal following distance upper limit and the optimal following distance lower limit. The dynamics index is
[0096]
[0097] Economic model module: used to establish the economic model of the controlled vehicle based on the instantaneous fuel consumption of the engine and the instantaneous equivalent fuel consumption of electric energy. The economic model is
[0098]
[0099] Economic index calculation module: used to construct economic index according to economic model. Economic index is
[0100]
[0101] Standardization module: used to standardize the dynamic index and economic index to obtain standard dynamic index and standard economic index, and Calculate the standardized dynamic index J t ' rack and standardized economic performance index J e ' co .
[0102] Nash equilibrium solution module: used to construct a game payoff matrix based on several feasible output powers of the engine and several feasible output powers of the motor. Each element of the game payoff matrix is a standard dynamic performance index and a standard economic performance index under a specific feasible output power of the engine and a specific feasible output power of the motor. The Nash equilibrium solution of the game payoff matrix is used to obtain the converged feasible output power of the engine and the feasible output power of the motor to control the controlled vehicle. This module also includes
[0103] Initial module: randomly select a feasible output power of an engine;
[0104] Iteration module: based on the selected feasible output power of the engine, the motor output power that minimizes the standardized dynamic performance index is solved; based on the obtained motor output power, the engine output power that minimizes the standardized economic performance index is solved;
[0105] And, control output module: repeatedly call the iteration module process to iterate until the final output motor output power and engine output power converge. If the final result does not converge, call the initial module to re-select a feasible output power of the engine for iteration.
Claims
1. A hybrid vehicle following control method based on Nash equilibrium solution, characterized in that: include: include: The speed model of the controlled vehicle is established based on the longitudinal dynamics model of the hybrid vehicle; Calculate the upper limit and lower limit of the optimal following distance according to the vehicle speed obtained from the vehicle speed model; The dynamic index is constructed by the upper limit of the optimal following distance and the lower limit of the optimal following distance; Establishing the economic model of the controlled vehicle based on the instantaneous fuel consumption of the engine and the instantaneous equivalent fuel consumption of electric energy; Construct economic indicators based on economic models; The power performance index and the economic performance index are standardized to obtain a standard power performance index and a standard economic performance index, wherein the power performance index and the economic performance index are both related to the engine power and the motor power; Constructing a game payoff matrix based on several feasible output powers of the engine and several feasible output powers of the motor, wherein each element of the game payoff matrix is a standard power performance index and a standard economic performance index under a specific feasible output power of the engine and a specific feasible output power of the motor; The game payoff matrix is solved for Nash equilibrium to obtain converged engine feasible output power and motor feasible output power for controlling the controlled vehicle.
2. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 1 is characterized in that: The Nash equilibrium solution for the game payoff matrix comprises the following steps: S1, randomly select a feasible output power of an engine; S2. Calculate the motor output power that minimizes the standardized dynamic performance index based on the selected engine feasible output power; S3, based on the motor output power obtained in S2, solve the engine output power that minimizes the standardized economic index; Repeat the process of S2 and S3 for iteration until the final output motor output power and engine output power converge. If the final result does not converge, return to S1 and re-select a feasible output power of the engine for iteration.
3. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 1 or 2, characterized in that: The dynamic index is in, is the upper limit of the optimal following distance, is the lower limit of the optimal following distance, α is the adjustment coefficient, L(k) is the current following distance.
4. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 3 is characterized in that: in v h (k) is the vehicle speed determined by the vehicle speed model.
5. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 4 is characterized in that: The value of α is 0.6~0.
7.
6. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 1 or 2, characterized in that: The vehicle speed model is Among them, P e is the engine output power; P m is the motor output power; r is the tire radius; F r = mgf cosθ is the rolling resistance; is air resistance; F g =mg sinθ is the acceleration resistance; m is the curb weight of the controlled vehicle; g is the acceleration of gravity; f is the rolling resistance coefficient; C d is the air resistance coefficient of the controlled vehicle; ρ is the air density; A is the windward area of the controlled vehicle; v h is the speed of the controlled vehicle; θ is the road slope; δ is the rotational mass conversion coefficient of the controlled vehicle.
7. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 1 or 2, characterized in that: The economic indicators are Among them, P e is the engine output power; η e is the engine efficiency; H f is the calorific value of fuel oil; P m is the motor output power; η m is the motor efficiency; η b is the battery efficiency; s is the equivalent factor.
8. The hybrid vehicle following control method based on Nash equilibrium solution according to claim 1 or 2, characterized in that: The standardization process is carried out according to the formula where X′ is the standardized data, X is the original indicator data, and X min is the minimum value among the indicators, X max is the maximum value among the indicators.
9. A hybrid vehicle following control device based on Nash equilibrium solution, characterized in that: include: Dynamic model module: used to establish the speed model of the controlled vehicle based on the longitudinal dynamic model of the hybrid vehicle; Dynamic index calculation module: used to calculate the upper limit and lower limit of the optimal following distance according to the vehicle speed obtained by the vehicle speed model, and construct the dynamic index by the upper limit and lower limit of the optimal following distance; Economic model module: used to establish the economic model of the controlled vehicle based on the instantaneous fuel consumption of the engine and the instantaneous equivalent fuel consumption of electric energy; Economic index calculation module: used to construct economic indicators based on economic models; A standardization module: used for standardizing the power performance index and the economic performance index to obtain a standard power performance index and a standard economic performance index, wherein the power performance index and the economic performance index are both related to the engine power and the motor power; And, a Nash equilibrium solving module: used to construct a game benefit matrix based on several feasible output powers of the engine and several feasible output powers of the motor, each element of the game benefit matrix is a standard dynamic index and a standard economic index under a specific engine feasible output power and a specific motor feasible output power; performing Nash equilibrium solving on the game benefit matrix to obtain converged engine feasible output power and motor feasible output power for controlling the controlled vehicle.
10. The hybrid vehicle following control device based on Nash equilibrium solution according to claim 9, characterized in that: The Nash equilibrium solving module comprises: Initial module: randomly select a feasible output power of an engine; Iteration module: based on the selected feasible output power of the engine, the motor output power that minimizes the standardized dynamic performance index is solved; based on the obtained motor output power, the engine output power that minimizes the standardized economic performance index is solved; And, control output module: repeatedly call the iteration module process to iterate until the final output motor output power and engine output power converge. If the final result does not converge, call the initial module to re-select a feasible output power of the engine for iteration.