Cruise system and control method based on global optimization of energy management

Abstract

The present invention is applicable to fields that require optimization of cruise control to improve the comprehensive performance of vehicles, and specifically discloses a cruise system and control method based on global optimization of energy management, the system including a power demand prediction module for predicting climbing power demand, a motor operating condition prediction module for predicting climbing motor operating conditions, a climbing optimization module for performing climbing optimization, a recovery energy calculation module for calculating downhill recoverable potential energy, and a speed planning module for planning downhill speed. The corresponding control method includes the above-mentioned working steps. The present invention achieves control optimization of complex road conditions by predicting climbing power demand, motor operating conditions, sprinting, locking gears, calculating downhill recovery potential energy, planning speed and other measures to improve the power performance and economy of the vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile drive control, and in particular to a cruise system and a control method based on energy management optimization. Background Art

[0002] The vehicle cruise function is used to control the car's constant speed. Once the car is set to cruise mode, the on-board controller will continuously adjust the driving force according to the road conditions and the car's driving resistance, so that the car always maintains the set speed without operating the accelerator. The purpose of using the cruise system is mainly to reduce driver fatigue, avoid engine speed fluctuations, and accurately control driving speed.

[0003] The Chinese patent "Predictive vehicle speed control method, device, equipment and storage medium for cruise control", publication number CN116494972A, publication date 2023.07.28, discloses a predictive vehicle speed control method for cruise control, the method is applied to heavy-duty vehicles, the method includes: outputting first indication information, the first indication information is used to indicate the control of the heavy-duty vehicle to enter a slope rushing state; controlling the heavy-duty vehicle to enter the slope rushing state, and adjusting the cruise setting speed from the set first speed to the second speed, wherein the second speed is greater than the first speed; outputting second indication information, the second indication information is used to indicate the control of the heavy-duty vehicle to exit the slope rushing state; controlling the heavy-duty vehicle to exit the slope rushing state, and adjusting the cruise setting speed from the second speed to the first speed.

[0004] However, the current cruise control system has problems on mountainous or hilly roads: insufficient power when climbing, making it difficult for the vehicle to reach the preset speed; when going downhill, the vehicle slides downhill, exceeds the preset speed and requires the driver to brake frequently, which not only causes the vehicle to exit the cruise mode, but also causes a loss of braking energy, reducing economy. Summary of the invention

[0005] In view of the above technical problems, the purpose of the present invention is to provide a cruise system and control method based on global optimization of energy management, which can improve the vehicle's power and economy by predicting climbing power requirements, optimizing climbing gears, and utilizing downhill potential energy recovery.

[0006] To achieve the above objectives, in a first aspect, the cruise system based on global optimization of energy management designed by the present invention is characterized by comprising:

[0007] A power demand prediction module is used to predict the power demand of the vehicle's subsequent trip based on map information, vehicle parameters and driving conditions;

[0008] A motor operating condition prediction module is used to predict the motor operating point based on the predicted power demand;

[0009] The hill climbing optimization module is used to control the vehicle to accelerate in advance and maintain the current gear when it is judged that there is a large climbing power demand, so as to avoid frequent gear changes when climbing.

[0010] Preferably, the slope climbing optimization module is specifically used for:

[0011] According to the motor operating point and efficiency curve, determine whether the motor operating condition will deteriorate;

[0012] If the motor's operating condition deteriorates, it is accelerated before reaching the slope to make the motor operate in a more efficient area.

[0013] Preferably, the power demand prediction module includes:

[0014] The vehicle power calculation unit is used to calculate the vehicle power demand based on map information and vehicle parameters;

[0015] The driving resistance calculation unit is used to calculate the driving resistance according to the driving conditions.

[0016] As a preferred solution, the cruise system further includes:

[0017] A recovery energy calculation module, used to calculate the downhill recoverable energy according to the downhill power demand;

[0018] The speed planning module is used to plan the speed of the vehicle before and after going downhill based on the calculated recoverable energy of downhill, and to recover energy using the downhill potential energy.

[0019] Preferably, the recovered energy calculation module is specifically used for:

[0020] Calculate braking energy loss based on downhill power demand;

[0021] The recoverable energy for downhill driving is calculated based on the downhill speed difference.

[0022] In a second aspect, the present invention further provides a cruise control method based on the above system, comprising the following steps:

[0023] A power demand prediction step, predicting the power demand of the vehicle's subsequent trip based on map information, vehicle parameters and driving conditions;

[0024] A motor operating condition prediction step, predicting the motor operating point according to the predicted power demand;

[0025] The hill climbing optimization step is to control the vehicle to accelerate in advance and maintain the current gear when it is judged that there is a large climbing power demand to avoid frequent gear changes when climbing.

[0026] Preferably, the climbing optimization step specifically includes:

[0027] Determine whether the motor operating condition will deteriorate based on the motor operating point and efficiency curve;

[0028] If the motor's operating condition deteriorates, it is accelerated before reaching the slope to make the motor operate in a more efficient area.

[0029] Preferably, the power demand prediction step specifically includes:

[0030] Calculate vehicle power requirements;

[0031] Calculate the driving resistance.

[0032] As a preferred solution, the cruise control method further includes:

[0033] A recovery energy calculation step, calculating the downhill recoverable energy according to the downhill power demand;

[0034] The speed planning step plans the speed of the vehicle before and after the downhill slope according to the calculated recoverable energy of the downhill slope, and utilizes the downhill potential energy to recover energy.

[0035] Preferably, the recovery energy calculation step specifically includes:

[0036] Calculate braking energy loss based on downhill power demand;

[0037] The recoverable energy for downhill driving is calculated based on the downhill speed difference.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention adjusts the vehicle speed in advance according to the motor working condition prediction result and locks the climbing gear, which can effectively improve the vehicle's climbing power performance. By calculating the recoverable potential energy of downhill driving and reducing the kinetic energy in advance through speed planning, the energy recovery rate during downhill driving can be effectively improved.

[0040] 1. According to the trend of the motor operating point when climbing, adjust the vehicle speed in advance to improve the climbing power and economy;

[0041] 2. Adopt the gear holding strategy when climbing to avoid power interruption caused by frequent gear shifting when climbing;

[0042] 3. Use the method of recovering energy using downhill potential energy to reduce braking loss and improve economy.

[0043] The present invention predicts the power demand during the climbing process and adjusts the vehicle speed in advance according to the motor efficiency curve to avoid the reduction of motor efficiency; locks the gear during acceleration to prevent power interruption caused by frequent gear shifting when climbing; calculates the recoverable potential energy when going downhill and uses speed planning to reduce kinetic energy in advance to achieve optimal energy utilization.

[0044] The vehicle cruise control is optimized for climbing and downhill conditions, mainly through power demand prediction, motor condition prediction, climbing optimization, energy recovery calculation and speed planning modules, to achieve control optimization for complex road conditions to improve the vehicle's power performance and economy. Thus, the vehicle's power performance during climbing is improved, and the energy recovery rate of the vehicle during downhill is improved.

[0045] The present invention can predict power demand, lock climbing gear, calculate downhill recovery energy, etc., so as to improve the climbing performance of the vehicle and the downhill energy utilization rate, thereby ensuring the vehicle's power and improving its economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a structural block diagram of the cruise system of the present invention;

[0047] Figure 2 is a flow chart of a cruise control method of the present invention;

[0048] Figure 3 It is the motor efficiency map. DETAILED DESCRIPTION

[0049] The technical solution of the present invention (including the preferred technical solution) is further described in detail below by means of the accompanying drawings and by listing some optional embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Example 1

[0051] like Figure 1 As shown, in order to improve the power performance of the vehicle during climbing, the present invention discloses a cruise system based on climbing power prediction, including: a power demand prediction module 101, a motor operating condition prediction module 102 and a climbing optimization module 103. The functions of each module are as follows:

[0052] The power demand prediction module 101 is used to predict the power demand curve of the vehicle in the subsequent climbing process based on the vehicle dynamics model according to map information, vehicle parameters (mass, drag coefficient, etc.) and real-time driving conditions (vehicle speed, road slope, etc.).

[0053] The motor operating condition prediction module 102 is used to predict the operating condition change trend of the motor during the climbing process, mainly the changes in speed and torque, based on the power demand curve output by the power demand prediction module in combination with the motor's characteristic curve, parameters, etc.

[0054] The hill climbing optimization module 103 is used to determine whether there is a large power demand during the hill climbing process, and if so, activate the hill climbing optimization strategy. Specifically, if it is predicted that the motor operating point will deteriorate and reduce efficiency, the module will control the vehicle to accelerate and sprint before entering the hill climbing process, and lock the current gear to prevent power interruption caused by frequent gear shifting during the hill climbing process.

[0055] The workflow is:

[0056] 1) The power demand prediction module predicts the ramp power demand curve;

[0057] 2) The motor operating condition prediction module predicts the motor operating condition according to the power demand curve;

[0058] 3) The hill climbing optimization module determines whether optimization is needed, and if so, performs sprinting and locking gear operations.

[0059] Through this system, the changes in the motor's operating conditions during climbing can be judged in advance, and control optimization such as sprinting and locking gears can be performed, thereby significantly improving the vehicle's climbing power performance.

[0060] Example 2

[0061] like Figure 2 As shown, the cruise control method based on the system of embodiment 1 includes:

[0062] The power demand prediction step 201 predicts the power demand curve during the climbing process based on the vehicle dynamics model according to the map information, vehicle parameters and real-time driving conditions;

[0063] The motor operating condition prediction step 202 predicts the motor operating condition change trend during the climbing process according to the predicted power demand curve and the motor characteristics;

[0064] In the hill climbing optimization step 203, it is determined whether there is a large power demand. If so, a sprint and a gear lock operation are performed.

[0065] The workflow of this method is:

[0066] 1) Predict the ramp power demand curve;

[0067] 2) Predict motor operating conditions based on the power demand curve;

[0068] 3) Determine if control needs to be optimized, and if so, sprint and lock the gear.

[0069] Through this method, the power demand and motor operating conditions can be predicted before climbing, and timely control can be performed to improve the vehicle's climbing power performance.

[0070] Example 3 Figure 1As shown, in order to improve the energy recovery rate of the vehicle during the downhill process, the present invention designs and discloses a cruise system based on downhill potential energy recovery, including: a recovery energy calculation module 301 and a speed planning module 302. The functions of each module are as follows:

[0071] The recovery energy calculation module 301 is used to calculate the recoverable potential energy in the downhill process according to the predicted information such as the slope and length of the downhill road and the parameters of the vehicle according to the energy conversion model;

[0072] The speed planning module 302 is used to plan the optimal speed of the vehicle before and after reaching the downhill slope according to the downhill recoverable potential energy calculated by the recovery energy calculation module, so as to convert the kinetic energy of the vehicle into potential energy for recovery.

[0073] The workflow is:

[0074] 1) The recovery energy calculation module calculates the recoverable potential energy downhill;

[0075] 2) The speed planning module plans the vehicle speed based on the calculation results.

[0076] Through this system, the recoverable potential energy of downhill driving can be calculated in advance, and the vehicle speed can be planned for energy conversion, thereby significantly improving the energy recovery rate during downhill driving.

[0077] Example 4

[0078] like Figure 2 As shown, the cruise control method based on the system of embodiment 3 includes:

[0079] Recovered energy calculation step 401, calculating downhill recoverable potential energy according to downhill information;

[0080] The speed planning step 402 plans the optimal speed of the vehicle before and after going downhill according to the calculated recoverable potential energy.

[0081] The workflow of this method is:

[0082] 1) Calculate the recoverable potential energy downhill;

[0083] 2) Plan the vehicle speed based on the calculation results.

[0084] Through this method, the recoverable potential energy during downhill driving can be calculated in advance, and the vehicle speed can be planned for energy optimization conversion, thereby improving the energy recovery utilization rate during downhill driving.

[0085] Example 5

[0086] In view of the problems existing in the cruise control system on mountainous or hilly roads, the present invention discloses a cruise control system based on global optimization of energy management, comprising:

[0087] A power demand prediction module 101 predicts the power demand for climbing;

[0088] A motor operating condition prediction module 102 predicts the motor operating condition for climbing a slope;

[0089] A slope climbing optimization module 103 performs slope climbing optimization;

[0090] The recovery energy calculation module 301 calculates the downhill recoverable potential energy;

[0091] The speed planning module 302 plans the downhill speed.

[0092] The system can predict the energy demand for climbing, accelerate in advance to increase the vehicle's kinetic energy, and improve the gearbox shift point to avoid ineffective up and downshifts; it can predict the energy contribution of downhill, reduce vehicle power, and use downhill potential energy to compensate for speed loss and improve downhill economy. The overall system optimization is achieved through climbing prediction and optimization and downhill potential energy recovery.

[0093] Combined with the road information ahead fed back by the ADAS map, the driving force and braking force requirements of the subsequent journey are predicted. Based on the estimated driving energy requirements and braking energy requirements, the vehicle speed is pre-adjusted to increase or decrease in the cruising scenario, and the vehicle kinetic energy is increased and released in advance for climbing and downhill conditions to improve the climbing ability and downhill potential energy recovery ability.

[0094] Example 6

[0095] like Figure 2 As shown, the cruise control method based on the system of embodiment 3 includes:

[0096] Step 201, predicting the climbing power demand.

[0097] The vehicle power demand prediction is to analyze the driving power demand of the subsequent trip by combining the predicted road slope information, the current vehicle mass, the vehicle driving resistance characteristics, and the vehicle speed estimated by the driving behavior. The driving power demand estimation logic refers to the vehicle dynamics theory, including:

[0098]

[0099] P=Fvη t

[0100] T=Fr

[0101] Where: F is the driving force of the vehicle; m is the mass of the vehicle; g is the acceleration of gravity; f is the rolling resistance coefficient; α is the slope angle; C d is the air resistance coefficient; A is the frontal area of ​​the vehicle; v is the cruising speed; δ is the rotational mass conversion coefficient; a is the acceleration; η t is the transmission efficiency; T is the torque; r is the tire radius.

[0102] Step 202, predicting the climbing motor operating condition.

[0103] Based on the predicted power demand curve and combined with the motor characteristics, the motor's operating condition change trend during the climbing process is predicted.

[0104] The map and energy estimation model are combined to estimate the subsequent climbing torque demand. When climbing, the operating trend of the motor is that the speed decreases and the torque increases.

[0105] Step 203, performing hill climbing optimization.

[0106] Step 2031, optimizing ramp control based on the motor operating point.

[0107] The operating trend of the motor when climbing a slope is that the speed decreases and the torque increases. Combined with the motor efficiency curve, when it is predicted that the motor's climbing operating point will deteriorate, acceleration and ramp control are performed in advance to make the motor work at a higher efficiency point when climbing a slope.

[0108] Step 2032, gear holding control.

[0109] When going uphill, the motor speed will increase first, then decrease after entering the slope, which will cause upshifting when going uphill and downshifting after entering the slope, resulting in power loss. This patent adopts a gear retention strategy for going uphill. When actively going uphill, gear shifting is prohibited to avoid repeated upshifting and downshifting control. This prevents power interruption from affecting vehicle dynamics.

[0110] Step 401, calculating the recoverable downhill potential energy.

[0111] In conventional cruise control, when the downhill slope is relatively steep, the vehicle will slide downhill, causing the vehicle speed to exceed the road speed limit, or be much higher than the cruising speed set by the driver, requiring the driver to brake to maintain the speed. The resulting problem is that the cruise function is exited, and the loss of braking energy causes the vehicle's economy to deteriorate.

[0112] The present invention combines the map and the energy estimation model in step 201 to calculate the downhill power demand in real time, and integrates the power to obtain the downhill recoverable energy (braking loss energy).

[0113] W=∫P(t)dt

[0114] Where W is the recoverable energy when going downhill; P(t) is the power; and t is the time.

[0115] When downhill braking energy loss is estimated, the present invention performs kinetic energy and potential energy conversion control, that is, the vehicle kinetic energy is reduced by reducing the vehicle speed, and the kinetic energy is compensated by the energy obtained from the downhill potential energy.

[0116]

[0117] Among them: δW is the estimated braking energy loss and recoverable energy; m is the vehicle mass; v1 is the vehicle speed before kinetic energy reduction; v2 is the vehicle's final speed.

[0118] Step 402, planning the downhill speed.

[0119] Combined with the deceleration control of the vehicle's sliding characteristics, as in step 401, the vehicle's kinetic energy is reduced in advance according to the expected downhill potential energy, and the expected target vehicle speed is obtained according to this strategy. The current vehicle speed is adjusted to the expected target vehicle speed, and the braking loss is avoided by free deceleration. In order to achieve the speed reduction to the expected value when going downhill, free sliding deceleration is performed, and the vehicle driving force is zero, thereby calculating the vehicle's deceleration, and combining the initial speed, final speed, deceleration and other information to calculate the approximate deceleration distance, and performing free deceleration control when the vehicle is less than this distance from the ramp.

[0120] The present invention achieves control optimization for complex road conditions by predicting climbing power requirements and motor operating conditions, performing sprinting, locking gears, calculating downhill recovery potential energy, planning speed and other measures to improve the vehicle's power performance and economy.

[0121] Those skilled in the art will readily appreciate that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, combinations, replacements, improvements, etc. made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. A cruise system based on global optimization of energy management, characterized in that: include: A power demand prediction module is used to predict the power demand of the vehicle's subsequent trip based on map information, vehicle parameters and driving conditions; A motor operating condition prediction module is used to predict the motor operating point based on the predicted power demand; The hill climbing optimization module is used to control the vehicle to accelerate in advance and maintain the current gear position when it is judged that there is a large hill climbing power demand, so as to avoid frequent gear changes when climbing; The ramp optimization module determines whether the motor operating condition will deteriorate based on the motor operating point and the efficiency curve. If the motor operating condition deteriorates, the motor is accelerated before reaching the ramp, so that the motor operates in a more efficient area.

2. The cruise system based on global optimization of energy management according to claim 1, characterized in that: The power demand prediction module comprises: The vehicle power calculation unit is used to calculate the vehicle power demand based on map information and vehicle parameters; The driving resistance calculation unit is used to calculate the driving resistance according to the driving conditions.

3. The cruise system based on global optimization of energy management according to claim 1 or 2, characterized in that: The cruise system also includes: A recovery energy calculation module, used to calculate the downhill recoverable energy according to the downhill power demand; The speed planning module is used to plan the speed of the vehicle before and after going downhill based on the calculated recoverable energy of downhill, and to recover energy using the downhill potential energy.

4. The cruise system based on global optimization of energy management according to claim 3, characterized in that: The recovery energy calculation module is specifically used for: Calculate braking energy loss based on downhill power demand; The recoverable energy for downhill driving is calculated based on the downhill speed difference.

5. A cruise control method based on the system according to any one of claims 1 to 4, characterized in that: The following steps are involved: A power demand prediction step, predicting the power demand of the vehicle's subsequent trip based on map information, vehicle parameters and driving conditions; A motor operating condition prediction step, predicting the motor operating point according to the predicted power demand; Hill climbing optimization step: when it is judged that there is a large hill climbing power demand, the vehicle is controlled to accelerate in advance and maintain the current gear to avoid frequent gear changes when climbing; The ramp optimization step specifically includes: judging whether the motor operating condition will deteriorate according to the motor operating point and the efficiency curve; If the motor's operating condition deteriorates, it is accelerated before reaching the slope to make the motor operate in a more efficient area.

6. The cruise control method according to claim 5, characterized in that: The power demand prediction step specifically includes: Calculate vehicle power requirements; Calculate the driving resistance.

7. The cruise control method according to claim 5 or 6, characterized in that: The cruise control method further comprises: A recovery energy calculation step, calculating the downhill recoverable energy according to the downhill power demand; The speed planning step plans the speed of the vehicle before and after the downhill slope according to the calculated recoverable energy of the downhill slope, and utilizes the downhill potential energy to recover energy.

8. The cruise control method according to claim 7, characterized in that: The recovery energy calculation step specifically includes: Calculate braking energy loss based on downhill power demand; The recoverable energy for downhill driving is calculated based on the downhill speed difference.

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