Method and device for controlling cruise function of vehicle

Abstract

The invention discloses a control method and device for a vehicle cruise function. The method comprises the steps that constant-speed cruise related data are obtained; if the constant-speed cruise related data represents that the current situation meets the planning condition, speed planning is conducted based on current vehicle motion information and the target speed, and a planned speed curve is obtained; taking the planned speed curve as a reference, and performing PI control based on the target speed and the current speed to obtain a cruise speed control request torque; a vehicle speed is controlled based on the cruise speed control request torque. According to the scheme, the speed planning of the S-shaped speed curve can be automatically carried out when the constant-speed cruise meets the specific conditions, the comfort of the constant-speed cruise in the process from the initial speed to the target speed is fully considered, it is guaranteed that the acceleration is smoothly planned to 0 while the speed is smoothly planned to the target speed, and the driving experience of a user is optimized.

Description

Technical Field

[0001] The present application relates to the field of automatic driving control technology, and more specifically, to a control method and device for a vehicle cruise function. Background Art

[0002] Cruise control is a car assisted driving technology, also known as cruise control system. It can help drivers maintain a stable speed on the highway without having to constantly step on the accelerator, thereby reducing driver fatigue and improving driving comfort. The cruise control system usually sets the target speed through a button or control panel on the vehicle. Once the target speed is set, the system automatically controls the accelerator and brakes to keep the vehicle stable at the set speed.

[0003] In the process of cruise control from the current speed to the target speed, the commonly used control method is PI (proportional integral) control. PI control adjusts the acceleration and deceleration of the vehicle according to the error between the real-time speed of the vehicle and the target speed to achieve a smooth change in speed.

[0004] However, when the vehicle speed reaches the target speed, PI control adjusts the vehicle's torque and speed according to the current speed error. When the difference is too large, PI control will give a large torque value, which will cause overshoot from the control perspective and cause a sense of frustration from the driving perspective. PI control cannot take into account driving comfort. Summary of the invention

[0005] In view of this, this application provides the following technical solutions:

[0006] The first aspect of the present application provides a method for controlling a vehicle cruise function, comprising:

[0007] Get cruise control related data;

[0008] If the cruise control related data indicates that the current situation meets the planning conditions, speed planning is performed based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve;

[0009] Taking the planned speed curve as a reference, performing PI control based on the target speed and the current speed to obtain a cruising speed control request torque;

[0010] The vehicle speed is controlled based on the cruising speed control request torque.

[0011] In a possible implementation, if the cruise control related data indicates that the cruise enabling state has been entered and there is an updated target speed, it is determined that the planning condition is met.

[0012] In a possible implementation, the speed planning based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve includes:

[0013] When the difference between the target speed and the current speed exceeds a set threshold, speed planning is performed based on the current vehicle motion information and the target speed to obtain a planned speed curve.

[0014] In a possible implementation, the speed planning based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve includes:

[0015] Obtaining initial data, the initial data including an initial speed, a target speed, an initial acceleration, an initial jerk change rate, a jerk limit value, and an acceleration limit value, wherein the initial speed is the current speed;

[0016] Based on the initial data, the duration of the jump change rate in each time period is determined, and each time period includes the first initial value time period t 01 , the first holding period t 12 , the first reverse initial value period t 23 , the jump remains at 0 period t 34 , the second reverse initial value period t 45 , the second holding period t 56 and the second initial value period t 67 ;

[0017] The planned speed curve is determined based on the duration of the jump change rate in each time period.

[0018] In a possible implementation, the calculating and determining, based on the initial data, the duration of the jump change rate in each time period includes:

[0019] determining a planning type based on the initial speed and the target speed;

[0020] Determining an acceleration curve based on the planning type and the value of the initial acceleration;

[0021] updating an initial jerk rate of change based on the acceleration curve;

[0022] The duration of the jump rate of change in each time period is determined based on the updated initial jump rate of change and other initial data.

[0023] In a possible implementation, taking the planned speed curve as a reference, performing PI control based on the target speed and the current speed, and obtaining the cruise speed control request torque includes:

[0024] The acceleration curve is used as a feedforward control signal of PI control, and the planned speed curve is used as a reference. PI control is performed based on the target speed and the current speed to obtain a cruising speed control request torque.

[0025] In one possible implementation, the acceleration limit includes an acceleration increase limit and a deceleration acceleration limit. When the planning type is an acceleration increase plan, the acceleration curve is limited to the interval [0, acceleration increase limit]; when the planning type is a deceleration plan, the acceleration curve is limited to the interval [deceleration acceleration limit, 0].

[0026] In a possible implementation, the jump is calculated to be kept at 0 for a period of time t 34 When the duration is , it is calculated based on the duration of other time periods according to the rounded value of time sampling.

[0027] In a possible implementation, it also includes:

[0028] receiving a pedal request torque;

[0029] If the pedal requested torque is greater than the cruising speed control requested torque, the vehicle speed is controlled based on the pedal requested torque.

[0030] A second aspect of the present application provides a control device for a vehicle cruise function, comprising:

[0031] A data acquisition module is used to obtain cruise control related data;

[0032] A speed planning module, configured to perform speed planning based on current vehicle motion information and target speed to obtain an S-shaped planned speed curve when the cruise control related data indicates that the current situation meets the planning conditions;

[0033] A PI control module, configured to use the planned speed curve as a reference, perform PI control based on the target speed and the current speed, and obtain a cruise speed control request torque;

[0034] A vehicle control module is configured to control a vehicle speed based on the cruise speed control request torque.

[0035] It can be known from the above technical scheme that the embodiment of the present application discloses a control method and device for the cruise function of a vehicle, the method comprising: obtaining cruise control related data; if the cruise control related data indicates that the current situation meets the planning conditions, speed planning is performed based on the current vehicle motion information and the target speed to obtain a planned speed curve; using the planned speed curve as a reference, PI control is performed based on the target speed and the current speed to obtain a cruise speed control request torque; and the vehicle speed is controlled based on the cruise speed control request torque. The above scheme can automatically perform speed planning of an S-shaped speed curve when the cruise control meets specific conditions, fully considering the comfort of the cruise control in the process from the starting speed to the target speed, ensuring that while the speed is smoothly planned to the target speed, the acceleration is also smoothly planned to 0, thereby optimizing the user's driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] Figure 1 It is a schematic diagram of the S-type speed curve;

[0038] Figure 2 A schematic diagram of the cruise control state relationship disclosed in the embodiment of the present application;

[0039] Figure 3 A flow chart of a method for controlling a vehicle cruise function disclosed in an embodiment of the present application;

[0040] Figure 4 This is a schematic diagram of the input and output control of the cruise control disclosed in the embodiment of the present application;

[0041] Figure 5 A schematic diagram of a cruise control speed planning process disclosed in an embodiment of the present application;

[0042] Figure 6 A flowchart of obtaining a planned speed curve disclosed in an embodiment of the present application;

[0043] Figure 7 This is a rendering of a cruise control speed planning algorithm disclosed in an embodiment of the present application;

[0044] Figure 8 A schematic diagram of the cruise control speed planning algorithm disclosed in the embodiment of the present application;

[0045] Fig. 9The planning state diagram of the cruise control with different starting accelerations disclosed in the embodiment of the present application;

[0046] Fig.10 A schematic diagram of a cruise control torque determination process disclosed in an embodiment of the present application;

[0047] Fig.11 This is a schematic diagram of the structure of a control device for a vehicle cruise function disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0049] The control method of the vehicle cruise function disclosed in the embodiment of the present application aims to plan an S-shaped speed curve when there is an updated target speed during the cruise control process. The S-shaped speed curve is a commonly used motion control curve, such as Figure 1 As shown in the figure, taking the speed increase as an example, it is divided into four stages: (1) the initial acceleration stage, the speed gradually increases, the acceleration gradually increases until it reaches the maximum value; (2) the constant acceleration stage, the speed continues to increase, but the acceleration remains at the maximum value; (3) the acceleration reduction stage, the acceleration begins to gradually decrease. The speed continues to increase, but the growth rate slows down; (4) the constant speed stage: the speed reaches and remains at the desired maximum value, and the acceleration is zero.

[0050] The S-shaped speed curve can ensure smooth speed changes during acceleration and deceleration, avoid sudden speed changes causing impact and damage to the system and equipment, and has the advantages of smoothness, energy saving, accuracy and stability during the movement of the control system. Therefore, after planning the S-shaped speed curve, the vehicle can be controlled to change to the target speed comfortably and smoothly according to the planned S-shaped speed curve.

[0051] In order to better understand the implementation of the technical solution of this application, the relevant content of cruise control is first introduced. The cruise control buttons of a vehicle usually include: Res button, used to restore the cruise speed and increase the target speed; Set button, used to enter cruise and reduce the target speed; Main button, the main switch of cruise mode; Cancel button, cancel cruise mode.

[0052] The cruise control has a maximum target speed, which is the maximum speed allowed for the vehicle (pre-defined by the vehicle when it leaves the factory) as the maximum target speed that can be set for the cruise control. The minimum speed for entering the cruise control is 30km / h (TBD). There are four states for the cruise control, such as Figure 2 As shown, they are OFF state, Standby state, Actv state, Ovrd state, where C represents the jump condition of the cruise state.

[0053] OFF state, cruise control is off, cruise control is the default state, in this state the recorded vehicle speed will be cleared;

[0054] Standby state, cruise control standby state, enters this state when the cruise main switch is pressed, at this time the target control speed of cruise control is 0km / h; in this state, press the Set key, the cruise mode responds to jump to the Actv state, the vehicle reads the current actual speed and sets it as the target cruise speed; press the Res key, the cruise mode responds to jump to the Actv state, the vehicle sets the recorded target speed as the current target speed, if the recorded target range is empty, it will not respond to enter the Actv state;

[0055] Actv state, cruise control is activated. When the cruise control function is in this state, the target speed can be adjusted through the cruise control function button; each time the Set button is pressed, the target speed decreases by 1km / h (TBD); pressing the Set button for 1 second (TBD) will reduce the target speed to the nearest multiple of 5 from the current speed. Continue to press and hold the button, and the target speed decreases by 5km / h every 1 second (TBD). The lowest speed during this process is the lowest cruise speed of 30km / h (TBD). Each time the Res button is pressed, the target speed increases by 1km / h (TBD); pressing the Res button for 1 second (TBD) will increase the target speed to the nearest multiple of 5 from the current speed. Continue to press and hold the button, and the target speed increases by 5km / h every 1 second (TBD). The highest speed during this process is the highest speed allowed by the cruise. Each time the speed changes in this state, the flag bit of the cruise target speed will be set to 1 (a trigger signal);

[0056] Ovrd state, cruise control takes over state. In Actv state, the user presses the accelerator pedal. When the torque requested by the accelerator pedal is greater than the cruise control speed request target torque, the cruise enters this state. During this state, pressing the Set button will set the current vehicle speed to the target cruise speed. The maximum speed of the target speed is the maximum speed allowed by the cruise.

[0057] In the implementation, the mutual jump between different cruise states can be realized according to the driver's button request, the current speed of the vehicle and the cruise jump conditions, and the vehicle's current cruise state, the expected speed (target speed) of the cruise, and the cruise target speed update flag can be output.

[0058] Figure 3 This is a flow chart of a method for controlling a vehicle cruise function disclosed in an embodiment of the present application. Figure 4 This is a schematic diagram of the cruise control input and output control disclosed in the embodiment of this application. Figure 3 and Figure 4 As shown, the control method of the vehicle cruise function may include:

[0059] Step 301: Obtain cruise control related data.

[0060] The cruise control related data may include, but is not limited to, cruise control status, cruise control target speed, cruise control target speed update flag, etc. The cruise control related data may be used to determine whether the current speed planning condition is met.

[0061] Step 302: If the cruise control related data indicates that the current situation meets the planning conditions, speed planning is performed based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve.

[0062] In implementation, the cruise control related data may indicate that the cruise control has entered the cruise enable state and there is an updated target speed, and the planning condition is determined to be met. The cruise enable state may be that the cruise control is in the Actv state or the Ovrd state, and there is an updated target speed, and the cruise control target speed update flag bit is 1, that is, there is a trigger signal for the target speed update.

[0063] The current vehicle operation information may include the current acceleration. Figure 4 In this step, an S-shaped planned speed curve can be planned according to the cruise control state, the expected speed of the cruise control, the cruise control target speed update flag, and the current acceleration of the vehicle. In the implementation, the cruise control speed is performed only when the cruise control state is Actv. If it is in Actv state, it is determined whether the cruise control target speed update flag is 1. If it is not 1, the target speed is not updated, and the previous target speed and acceleration are still output, and the process ends; when the target speed update flag is 1, the target speed, current speed, current acceleration, and re-planning flag required for speed control are updated.

[0064] How to plan and obtain the S-shaped planned speed curve will be introduced in the following embodiments and will not be described in detail here.

[0065] Step 303: Using the planned speed curve as a reference, PI control is performed based on the target speed and the current speed to obtain a cruising speed control request torque.

[0066] After obtaining the planned speed curve, it can be used as a reference value for PI control, and the cruise speed control request torque can be obtained through proportional integral control. Since the planned speed curve is an S-shaped speed curve, the speed control using it as a reference value for PI control can ensure that the vehicle speed is smooth and stable in the process of reaching the target speed.

[0067] Step 304: Control the vehicle speed based on the cruise speed control request torque.

[0068] The control method of the vehicle cruise function described in this embodiment is based on the trajectory planning of the S-shaped speed curve. During the transition from the current speed to the target speed of the cruise control, the vehicle speed adopts a comfortable S-shaped speed curve change, so that the vehicle speed smoothly reaches the target speed and the vehicle acceleration smoothly reaches 0, which helps to improve the driving comfort of the user.

[0069] In one implementation, the speed planning based on the current vehicle motion information and the target speed to obtain the S-shaped planned speed curve may include: when the difference between the target speed and the current speed exceeds a set threshold, speed planning is performed based on the current vehicle motion information and the target speed to obtain the planned speed curve.

[0070] In this implementation, when it is determined that speed planning is required, the difference between the target vehicle speed and the current vehicle speed is first determined. If it is less than or equal to the set threshold (such as 2km / h), the target speed and current acceleration are directly output. If it is greater than the set threshold, the speed planning algorithm is used to output an S-shaped planned speed curve and acceleration curve.

[0071] Figure 5 This is a schematic diagram of the cruise control speed planning process disclosed in the embodiment of this application, which can be combined with Figure 5 Understand the implementation of cruise control speed planning. Where A is the set threshold.

[0072] In this embodiment, if the difference between the target vehicle speed and the current vehicle speed is very small, the vehicle will not easily or will not feel jerky even if PI control is directly performed to reach the target vehicle speed, so speed planning is not required. When the difference between the target vehicle speed and the current vehicle speed exceeds a set threshold, an S-shaped speed curve from the current vehicle speed to the target vehicle speed is planned. This design can avoid wasting computing resources.

[0073] Figure 6 This is a flow chart of obtaining a planned speed curve disclosed in an embodiment of the present application. Figure 6As shown, in one implementation, the speed planning based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve may include:

[0074] Step 601: Obtain initial data, which may include an initial speed, a target speed, an initial acceleration, an initial jerk change rate, a jerk limit and an acceleration limit, wherein the initial speed is the current speed.

[0075] Step 602: Calculate and determine the duration of each period of the jump change rate based on the initial data, and the periods include the first initial value period t 01 , the first holding period t 12 , the first reverse initial value period t 23 , the jump remains at 0 period t 34 , the second reverse initial value period t 45 , the second holding period t 56 and the second initial value period t 67 .

[0076] The effect of speed planning is as follows Figure 7 As shown, from top to bottom are the jerk change rate curve, the jerk curve, the acceleration curve and the speed curve (S-shaped planned speed curve). The position and relationship of each time period mentioned above can be combined with the jerk change rate curve.

[0077] Figure 8 This is a schematic diagram of the cruise control speed planning algorithm disclosed in the embodiment of this application. Figure 8 As shown, the speed planning algorithm includes parameter preprocessing, parameter calculation, trajectory generation and PI control.

[0078] Parameter preprocessing: In this process, the initial conditions of the planning algorithm will be calculated. Get the current vehicle information, the current vehicle initial speed, the cruise control target speed, the current vehicle initial acceleration; calibrate the initial d value in the speed planning process (such as 10m / s 4 ), the maximum allowed acceleration MaxA value (such as 5m / s 2 ), the maximum allowed jump MaxJ value (such as 10m / s 3 ); the initial d value in the deceleration planning process (such as -10m / s 4 ), the maximum allowed acceleration MaxA value (such as -2m / s 2 ), the maximum allowed jump MaxJ value (such as -10m / s 3 ), where the maximum value refers to the value with the largest absolute value. Based on the above information, the initial acceleration of the plan, the initial d value of the plan, the maximum acceleration in the plan (acceleration limit), and the maximum jump in the plan (jump limit) are output. The specific judgment logic is as follows:

[0079] If the target vehicle speed is greater than the initial speed, that is, the acceleration planning, the initial d value of the planning, the maximum acceleration in the planning, and the maximum jump in the planning all use the values ​​calibrated in the acceleration planning process. Otherwise, the values ​​calibrated in the deceleration planning process are used.

[0080] The initial acceleration of the speed increase plan is the current vehicle acceleration. However, when the current vehicle acceleration is greater than the maximum allowed acceleration MaxA, the initial acceleration of the plan is set to MaxA. When the current vehicle acceleration is less than 0, the initial acceleration of the plan is set to 0. The initial acceleration of the speed reduction plan is the current vehicle acceleration. However, when the current vehicle acceleration is less than the maximum allowed acceleration MaxA, the initial acceleration of the plan is set to MaxA. When the current vehicle acceleration is greater than 0, the initial acceleration of the plan is set to 0. That is, the vehicle acceleration is divided into the six cases shown in the planning. The final plans for different cases are as follows: Fig. 9 As shown (both the acceleration planning and the deceleration planning include three situations: the initial acceleration is 0, the initial acceleration is the maximum value, and the initial acceleration is between 0 and the maximum value).

[0081] That is, the acceleration limit includes an acceleration increase limit and a deceleration acceleration limit. When the planning type is an acceleration increase plan, the acceleration curve is limited to the interval [0, acceleration increase limit]; when the planning type is a deceleration plan, the acceleration curve is limited to the interval [deceleration acceleration limit, 0].

[0082] Parameter calculation: In this process, the planning enable flag (replanning flag) will be given, and the initial value of the d curve and the time value t of each stage will be calculated. 01 , t 12 , t 23 , t 34 , t 45 , t 56 , t 67 Table 1 shows the meanings of some symbols involved in the present application.

[0083] Table 1 Symbols meaning

[0084]

[0085] (1) First, calculate t 01 , t 23 , t 45 , t 67 .

[0086] Let λt 01 =λt 23 =t 45 =t 67 ,according to We can get:

[0087] When the initial acceleration a0 = 0: it can be directly obtained

[0088] When the initial acceleration a0≠0: t is obtained by Tianheng formula 01 , t 23 , t 45 , t 67 In order to ensure that there is always a solution, it is necessary to ensure Therefore, it is necessary to ensure the relationship between the calibrated opening speed planning speed difference, the planned maximum acceleration allowed and the d0 value.

[0089] Specifically, based on the kinematic equation, the jump rate, jump and speed meet the following equations:

[0090]

[0091] Wherein, d represents the rate of change of jump, J represents the initial value of jump, a represents the initial value of acceleration, and v represents the initial value of velocity.

[0092] First, the limits (limits) of acceleration and jerk are not considered, so the first holding period t 12 , the jump remains at 0 period t 34 and the second holding period t 56 The default value is 0, which means t 12 =t 34 =t 56 =0, and according to formula (1), the following calculation is made:

[0093] From time t0 to time t1, d = d0, so:

[0094]

[0095] Among them, the determination of d value is given in advance, and its value is as follows Figure 2 The change curve of the jump rate of change d is shown in the figure, and only the time for which each value is maintained needs to be solved.

[0096] From time t2 to time t3, d = -d0, so:

[0097]

[0098] From t4 to t5, d = -d0; from t6 to t7, d = d0, and finally we can get J(t5), a(t5), v(t5), J(t7), a(t7), v(t7) about the unknown quantity t 01 , t 23 , t 45 , t 67 Next, let t01 = stop t 23 =t 45 =t 67 (stop>0) (In order to facilitate the solution, set t 01 =t 23 , t 45 =t 67 ), so:

[0099]

[0100] From the planning objectives, we can know We can obtain t 01 and the solution of the stop, so we can get t 01 , t 23 , t 45 , t 67 The value of .

[0101] (2) Calculate t 12 , t 56 .

[0102] Step (1) is to calculate t without considering the limits of acceleration and jerk. 01 , t 23 , t 45 , t 67 In actual situations, if the difference between the initial speed and the target speed is large, in order to ensure the smoothness of the planned speed curve, the maximum acceleration and maximum jerk are often limited. In this case, the limits of acceleration and jerk need to be considered. If the maximum acceleration and jerk in the process of planning to the target speed do not exceed their limits, then t 12 =t 34 =t 56 =0.

[0103] If the maximum acceleration value in the planned acceleration trajectory is greater than the preset acceleration limit, the acceleration limit can be substituted into the maximum value in the planned acceleration trajectory, and the jump change rate is recalculated to determine the non-zero time period (t 01 , t 23 , t 45 , t 67 ) duration.

[0104] Combination Figure 7 , before time point t3, the derivatives of acceleration are all positive, and after that, the acceleration is 0 and negative. Therefore, the acceleration value corresponding to time point t3 is the maximum acceleration value in the planned acceleration trajectory (the moment t3 in the deceleration plan is the minimum acceleration value), that is, a(t3) corresponds to the maximum acceleration value (extreme value).

[0105] If the maximum acceleration during the planning process is greater than the acceleration limit a of the constraintmax , that is |a(t3)|>|a max |Perform this step when:

[0106] (1) When planning the growth rate, that is, season

[0107]

[0108] (2) When planning for deceleration, that is, season

[0109]

[0110] Keep t 01 ,t 23 , t 45 , t 67 The relationship remains unchanged (stop t 01 =λt 23 =t 45 =t 67 (stop>0)), and solve again to get a new t 01 , t 23 ,t 45 , t 67 .

[0111] Similarly, if the maximum jump value in the planned jump trajectory is greater than the preset jump limit value, the jump limit value is substituted into the maximum value in the planned jump trajectory, and the duration of the jump change rate in each non-zero period is recalculated to determine.

[0112] Combination Figure 2 Before time point t1, the derivative of the jump is positive, and the jump has an extreme value at this moment. Time point t5 is similar and also corresponds to an extreme value. The largest of the two extreme values ​​is taken as the maximum jump value.

[0113] If the maximum jump value in the planning process is greater than the jump limit j of the constraint max , that is, |J(t1)|>j max or |J(t5)|>j max Perform this step when

[0114] (1) If |J(t1)|≥|J(t5)|

[0115] a. When planning the growth rate, season:

[0116] J(t1)=d0t 01 =j max

[0117] b. When planning for deceleration, season:

[0118] J(t1)=d0t 01 =-j max

[0119] (2) If |J(t1)|<|J(t5)|,

[0120] a. When planning the growth rate, season:

[0121] J(t5)=-d0t 45 +J(t3)=-j max

[0122] b. When planning for deceleration, season:

[0123] J(t5)=-d0t 45 + J(t3) = j max

[0124] Keep t 01 , t 23 , t 45 , t 67 The relationship between t and t remains unchanged, and the new solution is 01 , t 23 , t 45 , t 67 .

[0125] After recalculating and determining the duration of the jump change rate in each non-zero period, the method may further include: controlling acceleration compensation processing to make the planned speed the same as the target speed.

[0126] In the implementation of the scheme, if the maximum values ​​of acceleration and jerk are constrained and the duration of each non-zero period of jerk change rate is recalculated, the duration of each non-zero period will be reduced, resulting in a smaller target speed value in the final planning. To solve this problem, the time t that the jerk maintains the maximum value can be planned 12 , t 56 . At this time, t 01 , t 23 , t 45 , t 67 is a known quantity.

[0127] From time t1 to time t2, d = 0, so:

[0128]

[0129] Among them, J(t1), a(t1), v(t1) are the same as the values ​​in formula (2). The calculation method from time t2 to time t5 is the same as the previous calculation method. The values ​​of each time are recalculated to J(t5), a(t5), v(t5) according to formula (1). From time t5 to time t6, d = 0, so:

[0130]

[0131] From time t6 to time t7, d = d0, and finally we can get J(t7), a(t7), v(t7) about the unknown quantity t 12 , t 56 It is easy to find the expression of 12 = stop t 56 When a(t7)=0, then according to Solve for t 12 , t 56 The value of .

[0132] (3) Time sampling rounding: set the obtained time value to an integer multiple of the sampling time, and calculate t 34 That is, when calculating the jump to maintain 0 time period t 34 When the duration is , it is calculated based on the duration of other time periods according to the rounded value of time sampling.

[0133] When a0=0: After the above time value is sampled and rounded, according to the initial d0 and according to Solve for t 34 , for t 34 After sampling and rounding, Find the initial value of the d-curve.

[0134] When a0≠0: After the above time value is sampled and rounded, the initial value of the D curve is obtained according to a(t7)=0, and then Solve for t 34 , and then t 34 Sampling rounded.

[0135] In the implementation, due to the introduction of t 12 , t 56 , the value of the maximum acceleration a(t3) in the planning process will increase, so we can re-judge whether a(t3) exceeds the maximum acceleration a max .

[0136] If the maximum value in the latest planned acceleration trajectory is greater than the preset acceleration limit, the acceleration limit is substituted into the maximum value in the planned acceleration trajectory, and the first holding period t can be recalculated. 12 The duration of the second holding period t 56 Length of time.

[0137] If the maximum acceleration during planning is greater than the maximum acceleration of the constraint a max , that is |a(t3)|>|a max |Perform this step when:

[0138] (1) When planning the growth rate, that is, season

[0139]

[0140] (2) When planning for deceleration, that is, season

[0141]

[0142] Keep t at this time 12 , t 56 The relationship between t and t remains unchanged, and the new solution is 12 , t 56 .

[0143] If the maximum acceleration value during the planning to the target speed does not exceed the limit value, then t 34 =0.

[0144] Further, the first holding period t is recalculated 12 The duration of the second holding period t 56 After the time length, it may also include: controlling the speed compensation process to make the planned speed the same as the target speed value.

[0145] Since the acceleration exceeds the maximum value, t is recalculated. 12 , t 56 , the duration of these two segments will be reduced, resulting in a smaller final planned speed value. To solve this problem, the time t that the jump is kept at 0 can be planned 34 That is, if the actual maximum value of acceleration exceeds the allowed limit, the allowed limit will be used as the actual maximum value to calculate the time, which is equivalent to reducing the acceleration value, and the corresponding calculation time will also be reduced accordingly.

[0146] Assume t4>t3, the result from t1 to t3 is the same as that in step 2. From t3 to t4, d=0, j=0, so:

[0147]

[0148] According to formula (1), we continue to calculate J(t7), a(t7), v(t7), and finally we get J(t7) = 0, a(t7) = 0 and For the unknown quantity t 34 The linear equation of one variable is solved to get t34 The value of .

[0149] d trajectory generation: Calculate the initial value of the d curve and the time value of each stage according to the parameters in Table 1. Generate the planning trajectory of d (d curve) and give the planning completion flag.

[0150] Based on the above, step 602 may include: determining the planning type based on the initial speed and the target speed; determining the acceleration curve based on the planning type and the numerical value of the initial acceleration; updating the initial jump change rate based on the acceleration curve; and determining the duration of the jump change rate in each time period based on the updated initial jump change rate and other initial data.

[0151] Speed ​​trajectory generation: The desired speed is obtained by integration (corresponding to Figure 7 The lower speed curve, i.e. the planned speed curve), acceleration trajectory curve (corresponding to Figure 7 The third acceleration curve from top to bottom in Figure 1).

[0152] Step 603: Determine a planned speed curve based on the duration of the jump change rate in each time period.

[0153] The planned speed curve obtained in the previous step is used as the reference value of PI control to control the current vehicle speed.

[0154] The above content discloses the specific implementation of planning to obtain an S-shaped planning speed curve, which is convenient for technical personnel in the field to better understand and implement the technical solution of the present application.

[0155] Based on the disclosed contents of the aforementioned embodiments, the method of using the planned speed curve as a reference, performing PI control based on the target speed and the current speed, and obtaining the cruise speed control request torque may include: using the acceleration curve as a feedforward control signal for PI control, and using the planned speed curve as a reference, performing PI control based on the target speed and the current speed, and obtaining the cruise speed control request torque.

[0156] In this implementation, acceleration is used as feedforward control, and feedforward torque = acceleration * tire radius / transmission ratio. Adding feedforward control to the PI control implementation can make the final cruise speed control request torque more accurate.

[0157] In other implementations, the method for controlling a vehicle cruise function may further include: receiving a pedal request torque; and if the pedal request torque is greater than the cruise speed control request torque, controlling the vehicle speed based on the pedal request torque.

[0158] In the actual cruise control process, the user may increase the cruise control target speed by stepping on the accelerator pedal. This is when the cruise control system receives two torques, such as Figure 4 As shown, the two torques are the cruise speed control request torque and the pedal request torque.

[0159] In this embodiment, when the cruise control is in the Enbl (enabled) state, that is, the Actv or Ovrd state, if the torque value requested by the accelerator pedal is greater than the cruise control speed request torque, the accelerator pedal request torque is responded to, and the cruise control state is issued to the flag bit of Ovrd; otherwise, the cruise control speed request torque is responded to, and the cruise control state is issued to the flag bit of Actv. The flag bits related to the cruise control mode jump will be used as part of the conditions for the cruise control state jump. Fig.10 This is a schematic diagram of the cruise control torque determination process disclosed in the embodiment of the present application, which can be combined with Fig.10 Understand the content of this embodiment.

[0160] The technical solution of the present application determines the cruise mode and outputs the vehicle's current cruise mode, the desired cruise speed, and the cruise speed target update flag according to the driver's button request, the vehicle's current speed, and the cruise jump condition; then plans the target S-shaped speed curve through speed planning; then outputs the requested torque for the cruise speed through PI control; finally, after torque arbitration, the pedal torque and the speed control torque are determined, and then the requested torque for the cruise and the jump condition of the partial cruise mode are output.

[0161] Based on the above, the present application scheme takes into account the comfort of cruise control in the process from the starting speed to the target speed. The process adopts an S-shaped speed curve. While the speed is smoothly planned to the target speed, the acceleration is also smoothly planned to 0. In addition, the present application scheme allows a high degree of freedom in the process of starting the cruise control process. In this process, the maximum acceleration (acceleration limit) and maximum jump (jump limit) of the vehicle can be defined, so that the vehicle has more diverse controllability in the process.

[0162] For the aforementioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0163] The method is described in detail in the embodiments disclosed in the above-mentioned application. The method of the application can be implemented by various forms of devices. Therefore, the application also discloses a device, and a specific embodiment is given below for detailed description.

[0164] Fig.11 This is a schematic diagram of the structure of a control device for a vehicle cruise function disclosed in an embodiment of the present application, see Fig.11 As shown, the control device 110 of the vehicle cruise function may include:

[0165] The data acquisition module 1101 is used to obtain cruise control related data.

[0166] The speed planning module 1102 is used to perform speed planning based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve when the cruise control related data indicates that the current situation meets the planning conditions.

[0167] The PI control module 1103 is used to use the planned speed curve as a reference, perform PI control based on the target speed and the current speed, and obtain a cruising speed control request torque.

[0168] The vehicle control module 1104 is configured to control the vehicle speed based on the cruise speed control request torque.

[0169] The control device for the vehicle cruise function described in this embodiment is based on the trajectory planning of the S-shaped speed curve. During the transition from the current speed to the target speed of the cruise control, the vehicle speed adopts a comfortable S-shaped speed curve change, so that the vehicle speed smoothly reaches the target speed and the vehicle acceleration smoothly reaches 0, which helps to improve the driving comfort of the user.

[0170] The specific implementation of the control device for the above-mentioned vehicle cruise function and the various modules it contains, as well as other possible implementations can be found in the corresponding parts of the method embodiment, which will not be repeated here.

[0171] The control device for any one of the vehicle cruise functions in the above embodiments comprises a processor and a memory. The control device for the vehicle cruise function, the speed planning module, the PI control module, the vehicle control module, etc. in the above embodiments are all stored in the memory as program modules, and the processor executes the above program modules stored in the memory to implement corresponding functions.

[0172] The processor includes a kernel, which retrieves the corresponding program module from the memory. One or more kernels can be set, and the processing of the access data can be realized by adjusting the kernel parameters.

[0173] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0174] In an exemplary embodiment, a computer-readable storage medium is also provided, which can be directly loaded into the internal memory of a computer and contains software code. After being loaded and executed by a computer, the computer program can implement the steps shown in any embodiment of the control method for the vehicle cruise function described above.

[0175] In an exemplary embodiment, a computer program product is also provided, which can be directly loaded into the internal memory of a computer and contains software code. After being loaded and executed by the computer, the computer program can implement the steps shown in any embodiment of the control method for the vehicle cruise function described above.

[0176] Furthermore, an embodiment of the present application provides a vehicle, which may include at least one processor, and at least one memory and a bus connected to the processor; wherein the processor and the memory communicate with each other through the bus; the processor is used to call program instructions in the memory to execute the above-mentioned vehicle cruise function control method.

[0177] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0178] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0179] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0180] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling a vehicle cruise function, characterized in that: include: Get cruise control related data; If the cruise control related data indicates that the current situation meets the planning conditions, speed planning is performed based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve; Taking the planned speed curve as a reference, performing PI control based on the target speed and the current speed to obtain a cruising speed control request torque; The vehicle speed is controlled based on the cruising speed control request torque.

2. The method for controlling the vehicle cruise function according to claim 1, characterized in that: If the cruise control related data indicates that the cruise enabling state has been entered and there is an updated target speed, it is determined that the planning condition is met.

3. The method for controlling the vehicle cruise function according to claim 1, characterized in that: The speed planning is performed based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve, including: When the difference between the target speed and the current speed exceeds a set threshold, speed planning is performed based on the current vehicle motion information and the target speed to obtain a planned speed curve.

4. The method for controlling the vehicle cruise function according to claim 1, characterized in that: The speed planning is performed based on the current vehicle motion information and the target speed to obtain an S-shaped planned speed curve, including: Obtaining initial data, the initial data including an initial speed, a target speed, an initial acceleration, an initial jerk change rate, a jerk limit value, and an acceleration limit value, wherein the initial speed is the current speed; Based on the initial data, the duration of the jump change rate in each time period is determined, and each time period includes the first initial value time period t 01 , the first holding period t 12 , the first reverse initial value period t 23 , the jump remains at 0 period t 34 , the second reverse initial value period t 45 , the second holding period t 56 and the second initial value period t 67 ; The planned speed curve is determined based on the duration of the jump change rate in each time period.

5. The method for controlling the vehicle cruise function according to claim 4, characterized in that: The step of calculating and determining the duration of the jump change rate in each time period based on the initial data includes: determining a planning type based on the initial speed and the target speed; Determining an acceleration curve based on the planning type and the value of the initial acceleration; updating an initial jerk rate of change based on the acceleration curve; The duration of the jump rate of change in each time period is determined based on the updated initial jump rate of change and other initial data.

6. The method for controlling the vehicle cruise function according to claim 5, characterized in that: The method of using the planned speed curve as a reference and performing PI control based on the target speed and the current speed to obtain a cruise speed control request torque includes: The acceleration curve is used as a feedforward control signal of PI control, and the planned speed curve is used as a reference. PI control is performed based on the target speed and the current speed to obtain a cruising speed control request torque.

7. The method for controlling the vehicle cruise function according to claim 5, characterized in that: The acceleration limit includes an acceleration increase limit and a deceleration acceleration limit. When the planning type is an acceleration increase plan, the acceleration curve is limited to the interval [0, acceleration increase limit]; when the planning type is a deceleration plan, the acceleration curve is limited to the interval [deceleration acceleration limit, 0].

8. The method for controlling the vehicle cruise function according to claim 4, characterized in that: The jump is kept at 0 during the period t 34 When the duration is , it is calculated based on the duration of other time periods according to the rounded value of time sampling.

9. The method for controlling the vehicle cruise function according to claim 1, characterized in that: Also includes: receiving a pedal request torque; If the pedal requested torque is greater than the cruising speed control requested torque, the vehicle speed is controlled based on the pedal requested torque.

10. A control device for a vehicle cruise function, characterized in that: include: A data acquisition module is used to obtain cruise control related data; A speed planning module, configured to perform speed planning based on current vehicle motion information and target speed to obtain an S-shaped planned speed curve when the cruise control related data indicates that the current situation meets the planning conditions; A PI control module, configured to use the planned speed curve as a reference, perform PI control based on the target speed and the current speed, and obtain a cruise speed control request torque; A vehicle control module is configured to control a vehicle speed based on the cruise speed control request torque.

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