Vehicle slipping power control system and control method thereof

Abstract

The invention provides a vehicle slipping power control system and a control method thereof. The system comprises a front wheel vehicle speed sensor; a rear wheel vehicle speed sensor; the control unit is provided with a default slip critical value and is used for calculating a slip ratio according to the speed of the front wheel and the speed of the rear wheel; the PID control module is coupled with the control unit and is used for adjusting the output torque of the vehicle according to the slip ratio, the PID control module comprises a rising type PID control unit and a falling type PID control unit, a torque rising calculation formula is pre-stored in the rising type PID control unit, and a torque falling calculation formula is pre-stored in the falling type PID control unit; when the slip ratio exceeds the preset slip critical value, the control unit triggers the PID control module to select the rising type PID control unit or the falling type PID control unit to adjust the output torque according to the slip ratio.

Description

TECHNICAL FIELD

[0001] The present application relates to a vehicle slip power control system and its control method, in particular to a vehicle slip power control system and its control method that calculates the slip rate using the speed difference between the front and rear wheels and adjusts the output torque through a specific PID control algorithm. BACKGROUND

[0002] During vehicle driving, if the adhesion between the driving tire and the road surface is insufficient, the phenomenon of slip will occur. Slip not only reduces the handling and fuel economy of the vehicle, but in severe cases can also lead to loss of control. Therefore, effectively preventing wheel slip and maintaining good traction is very important for driving safety.

[0003] The prior art generally measures the wheel speed and calculates the wheel slip rate based on the speed difference, and then adjusts the engine output torque or brake torque based on the slip rate to suppress slip. However, this passive response method has a lag, which cannot be controlled in time and accurately, so that the slip situation cannot be effectively solved, and may cause the risk of secondary loss of control due to excessive correction.

[0004] In addition, the prior art generally uses a single PID control parameter to adjust the output torque, lacks recognition of different slip levels, and cannot make dynamic judgments and accurate responses, with limited control precision and real-time performance. Some technologies attempt to use complex fuzzy logic or neural network algorithms, but the model is complex, parameter tuning is difficult, and real-time calculation is large, which is difficult to implement in an embedded system.

[0005] During vehicle driving, especially on wet or bumpy roads, the wheels are prone to slip. In order to prevent vehicle loss of control and ensure driving safety, the prior art proposes a vehicle slip power control system (TCS), which adjusts the output torque of the vehicle to control the slip of the wheels. However, the existing control system may have slow response speed and poor stability when dealing with dynamically changing slip rates. And most vehicles only use a single mode PID controller to adjust the torque, which may not achieve the best effect under different road conditions. In particular, on wet or uneven roads, wheels are prone to slip or lose control, so an improved control system is needed to more effectively deal with wheel slip situations. SUMMARY

[0006] The application provides a vehicle slip power control system and a control method thereof, which is used for a vehicle and includes a front wheel speed sensor, a rear wheel speed sensor, a control unit configured to calculate a slip ratio according to the front wheel speed and the rear wheel speed, and a PID control module coupled to the control unit and configured to adjust the output torque of the vehicle according to the slip ratio, wherein the PID control module includes an up-type PID control unit and a down-type PID control unit, the up-type PID control unit is pre-stored with a torque up calculation formula, and the down-type PID control unit is pre-stored with a torque down calculation formula, and when the slip ratio exceeds the preset slip critical value, the control unit triggers the PID control module to select the up-type PID control unit or the down-type PID control unit according to the size of the slip ratio to adjust the output torque.

[0007] In an embodiment, the torque up calculation formula is:

[0008] Yn=Rising_P*△Xn+Rising_I*Σ△Xn+Rising_D*(△Xn-△X(n-1))

[0009] wherein,

[0010] △Xn is a current control error value;

[0011] Rising_P*△Xn is a proportional control amount;

[0012] Rising_I*∑△Xn is an integral control amount;

[0013] Rising_D*(△Xn-△X(n-1)) is a differential control amount;

[0014] The output torque Yn is obtained by adding the above control amounts.

[0015] In an embodiment, the torque down calculation formula is:

[0016] Yn=Falling_P*△Xn+Falling_I*Σ△Xn+Falling_D*(△Xn-△X(n-1))

[0017] wherein,

[0018] △Xn is a current control error value;

[0019] Falling_P*△Xn is a proportional control amount;

[0020] Falling_I*∑△Xn is an integral control amount;

[0021] Falling_D*(ΔXn-ΔX(n-1)) is a calculation of a differential control amount;

[0022] The above control amounts are added to obtain an output torque Yn.

[0023] In an embodiment, the slip rate calculation formula is: slip rate = front wheel speed / rear wheel speed; when the slip rate exceeds the preset slip threshold, the PID control module is triggered to act.

[0024] In an embodiment, the control unit further includes calculating a slip compensation value using a formula, and the slip compensation value = torque * slip value.

[0025] The application also provides a control method of a vehicle slip power control system, comprising:

[0026] Measuring the front wheel speed and the rear wheel speed;

[0027] Calculating the slip rate by a control unit receiving the front wheel speed and the rear wheel speed;

[0028] Determining whether the slip rate exceeds a preset slip threshold;

[0029] When the slip rate exceeds the threshold, the rising type PID control unit or the falling type PID control unit is selected according to the slip rate to adjust the output torque.

[0030] In an embodiment, the rising type PID control unit includes the following steps when it is running:

[0031] Calculating the current control error ΔXn;

[0032] Calculating the proportional control amount Rising_P*ΔXn;

[0033] Calculating the integral control amount Rising_I*∑ΔXn;

[0034] Calculating the differential control amount Rising_D*(ΔXn-ΔX(n-1));

[0035] The above control amounts are added to obtain an output torque Yn.

[0036] In an embodiment, the falling type PID control unit includes the following steps when it is running:

[0037] Calculating the current control error ΔXn;

[0038] Calculating the proportional control amount Falling_P*ΔXn;

[0039] Calculating the integral control amount Falling_I*∑ΔXn;

[0040] The differential control amount Falling_D*(ΔXn-ΔX(n-1)) is calculated.

[0041] The control amounts are added to obtain the output torque Yn.

[0042] In one embodiment, the calculation step of calculating the slip ratio comprises: slip ratio = front wheel speed / rear wheel speed; when the slip ratio exceeds the preset slip threshold, the PID control module is triggered to act. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order that the features of the present application can be understood in detail, a more particular description of the application, some examples of which will be described with reference to the accompanying drawings, wherein some examples are shown. However, it is to be noted that the drawings show only typical examples of the application and therefore are not to be considered limiting of its scope, as the application can admit to other equally effective examples.

[0044] Figure 1 The system composition of the present application is shown in the figure.

[0045] Figure 2 The system action of the present application in actual operation is shown in the figure.

[0046] Figure 3 The system implementation steps of the present application are shown in the figure. DETAILED DESCRIPTION

[0047] The following description contains specific information pertaining to exemplary examples in the present application. The drawings in the present application and the detailed description accompanying them are only exemplary examples. However, the present application is not limited to these exemplary examples. Other variations and examples of the present application will be conceived by those skilled in the art. Unless otherwise specified, the same or corresponding components in the drawings can be indicated by the same or corresponding reference numerals. In addition, the drawings in the present application and the examples are generally not drawn to scale, and are not intended to correspond to the actual relative sizes.

[0048] For the purpose of consistency and ease of understanding, the same features are indicated by reference numerals in the exemplary drawings (although not so indicated in some examples). However, the features in different embodiments can be different in other aspects, and should not be narrowly limited to the features shown in the drawings.

[0049] The phrases "at least one of," "one or more of," and "one or more," as used herein, can be taken to mean that a feature, structure, or characteristic can be present in some embodiments, but not necessarily in other embodiments. Multiple instances of a feature, structure, or characteristic in one or more embodiments are not necessarily meant to be synonymous with each other. Furthermore, the use of the term "a" or "an" when used in conjunction with the term "comprising" can mean "one," but it also can mean "one or more," or "one or more of the same." Also, the use of the term "at least one" can mean "one," "one or more," or "one or more of the same." Further, it is also possible that different features, structures, or characteristics were used for different embodiments.

[0050] In addition, for purposes of explanation and non- limitation, specific details about certain methods, techniques, systems, architectures, etc. are set forth to provide an understanding of the described technology. In other instances, detailed descriptions of well-known methods, techniques, systems, architectures, etc. are omitted so as not to obscure the description of the described technology with unnecessary detail.

[0051] As shown in Figure 1 Figure 1 ​For the system composition schematic diagram of the present application, the present application provides a vehicle slip power control system 10 for a vehicle 11, such as a car, a motorcycle, etc., and the vehicle slip power control system 10 comprises a front wheel speed sensor 101, a rear wheel speed sensor 102, a control unit 103, and a PID control module 104, wherein the front wheel speed sensor 101 is used to measure a front wheel speed M1 of the vehicle 11, and the rear wheel speed sensor 102 is used to measure a rear wheel speed M2 of the vehicle 11; the control unit 103 can be a microprocessor or a microcontroller (MCU), which performs tasks such as calculation, data processing, and sending of control commands, and the control unit 103 is provided with a default slip critical value M3, and the control unit 103 is coupled with the front wheel speed sensor 101 and the rear wheel speed sensor 102, respectively, can receive the front wheel speed M1 and the rear wheel speed M2, and calculate a slip rate according to the front wheel speed M1 and the rear wheel speed M2, in an embodiment, the control unit 103 further comprises calculating a slip compensation value using a formula, and the slip compensation value = torque * slip value; the PID control module 104 is a "proportional-integral-derivative" controller (Proportional-Integral-Derivative Controller, PID), which is mainly used to accurately adjust the output torque of the vehicle to respond to different driving conditions and prevent wheel slip, and the PID control module 104 is coupled with the control unit 103 to adjust the output torque of the vehicle 11 according to the slip rate, and the PID control module 104 further comprises a rising type PID control unit 1041 and a falling type PID control unit 1042, the rising type PID control unit 1041 pre-stores a torque rising calculation formula M4, and the falling type PID control unit 1042 pre-stores a torque falling calculation formula M5; wherein when the slip rate exceeds the preset slip critical value M3, the control unit 103 triggers the PID control module 104 to select the rising type PID control unit 1041 or the falling type PID control unit 1042 to adjust the output torque according to the slip rate; in an embodiment, the slip rate calculation formula is: slip rate = front wheel speed / rear wheel speed;

[0052] When the slip rate exceeds the preset slip critical value M3, the PID control module 104 is triggered to act.

[0053] The Figure 1 In an embodiment, the torque rising calculation formula M4 is:

[0054] Yn = Rising_P * △Xn + Rising_I * Σ△Xn + Rising_D * (△Xn - △X(n-1))

[0055] Wherein,

[0056] ΔXn is the current control error value;

[0057] Rising_P*ΔXn is the proportional control value;

[0058] Rising_I*∑ΔXn is the integral control value;

[0059] Rising_D*(ΔXn-ΔX(n-1)) is the differential control value;

[0060] The above control values are added to obtain the output torque Yn.

[0061] The Figure 1 In one embodiment, the torque falling calculation formula M5 is:

[0062] Yn=Falling_P*△Xn+Falling_I*Σ△Xn+Falling_D*(△Xn-△X(n-1))

[0063] Wherein,

[0064] ΔXn is the current control error value;

[0065] Falling_P*ΔXn is the proportional control value;

[0066] Falling_I*∑ΔXn is the integral control value;

[0067] Falling_D*(ΔXn-ΔX(n-1)) is the differential control value;

[0068] The above control values are added to obtain the output torque Yn.

[0069] Please refer to Figure 2 , the actual operation of the system of the application, please refer to Figure 1, the front wheel speed sensor 101 and the rear wheel speed sensor 102 measure the front wheel speed Ml and the rear wheel speed M2 of the vehicle 11 respectively. The control unit 103 calculates the slip ratio according to the difference between the front and rear wheel speeds. When the slip ratio exceeds the preset slip threshold M3, the control unit 103 triggers the PID control module 104 to work. The algorithm used by the PID control module 104 includes the rising type PID control unit 1041 and the falling type PID control unit 1042. According to the size of the slip ratio, the control unit 103 selects to use the rising type PID control unit 1041 or the falling type PID control unit 1042 for control. When the slip ratio is large and continues to increase, that is, ΔXn> ΔX(n-1), indicating that the wheel slip is getting worse, at this time the control unit 103 starts the rising type PID control unit 1041. The formula of the rising type PID control unit 1041 is:

[0070] Yn = Rising_P * ΔXn + Rising_I * ΣΔXn + Rising_D * (ΔXn - ΔX(n-1))

[0071] Where Yn is the output torque control amount this time; Rising_P, Rising_I, Rising_D are the proportional, integral, and differential control parameters respectively.

[0072] The formula is essentially a linear combination of the current slip error ΔXn and its integral and differential, thereby generating a reasonable torque output Yn to make the wheel recover more adhesion and curb the slip trend, which can ensure that the output torque increases smoothly in the slip condition and avoid sudden changes to reduce the coupling effect.

[0073] On the contrary, when the slip ratio is large but starts to decrease, that is, ΔXn< ΔX(n-1), indicating that the wheel is recovering adhesion, at this time the control unit 103 starts the falling type PID control unit. The formula of the falling type PID control unit is:

[0074] Yn = Falling_P * ΔXn + Falling_I * ΣΔXn + Falling_D * (ΔXn - ΔX(n-1)),

[0075] Where Falling_P, Falling_I, Falling_D are specially tuned PID parameters. The formula can make the output torque Yn decrease smoothly and prevent the loss of adhesion caused by excessive correction of slip.

[0076] From the above, the separate design of the rising type PID control unit 1041 and the falling type PID control unit 1042 mainly avoids the problem of mutual offset of single PID parameters under different slip conditions, so that the control response is more reasonable and effective. Further, in actual application, the system calculation period is set to 5 milliseconds, i.e. 200 times per second, which ensures high real-time performance.

[0077] Please refer to Figure 3 , please refer to Figures 1-2 , the implementation method of the predictive maintenance system 10 of the present application is as follows:

[0078] First step S1: measuring the front wheel speed M1 and the rear wheel speed M2;

[0079] Second step S2: calculating the slip rate after the control unit 103 receives the front wheel speed M1 and the rear wheel speed M2; in an embodiment, the slip rate calculation formula is:

[0080] Slip rate = front wheel speed / rear wheel speed;

[0081] When the slip rate exceeds the preset slip critical value M3, the PID control module 104 is triggered.

[0082] Third step S3: judging whether the slip rate exceeds the preset slip critical value M3;

[0083] Fourth step S4: when the slip rate exceeds the preset slip critical value M3, the rising type PID control unit 1041 or the falling type PID control unit 1042 is selected according to the slip rate to adjust the output torque.

[0084] Please refer to Figure 3 , in an embodiment, the rising type PID control unit 1041 includes the following steps when it is running:

[0085] Calculate the current control error ΔXn;

[0086] Calculate the proportional control amount Rising_P*ΔXn;

[0087] Calculate the integral control amount Rising_I*∑ΔXn;

[0088] Calculate the differential control amount Rising_D*(ΔXn-ΔX(n-1));

[0089] Add the above control amounts to obtain the output torque Yn.

[0090] Please refer to Figure 3 , in an embodiment, the falling type PID control unit 1042 includes the following steps when it is running:

[0091] calculating a current control error ΔXn;

[0092] calculating a proportional control amount Falling_P*ΔXn;

[0093] calculating an integral control amount Falling_I*∑ΔXn;

[0094] calculating a differential control amount Falling_D*(ΔXn-ΔX(n-1));

[0095] adding the above control amounts to obtain an output torque Yn.

[0096] Please refer to Figure 3 In an embodiment, the calculation step of calculating the slip rate comprises:

[0097] slip rate = front wheel speed / rear wheel speed;

[0098] When the slip rate exceeds the preset slip threshold M3, the PID control module 104 is triggered to act.

[0099] Please refer to Figure 3 In an embodiment, the control unit 103 further comprises calculating a slip compensation value using a formula, and the slip compensation value = torque * slip value.

[0100] In summary, the vehicle slip power control system of the present application can more accurately and quickly respond to changes in slip rate, adjust the driving torque in real time, and effectively prevent slipping. The rising type and falling type PID controllers are set for the cases of increasing and decreasing slip rate, respectively, so that the control response is more reasonable and stable. On the basis of PID control, the slip compensation is superimposed to further improve the accurate control of traction force, and the control period is shorter, the calculation precision is high, and the purpose of ensuring real-time and efficient control effect is achieved.

[0101] The embodiments and the patent range disclosed do not necessarily need to achieve all the disclosed technical advantages or technical features. Furthermore, the abstract and the title are only for the convenience of patent document retrieval, and do not intend to limit the scope of the application in any aspect.

[0102] Explanation of reference signs

[0103] 10: vehicle slip power control system

[0104] 101: front wheel speed sensor

[0105] 102: rear wheel speed sensor

[0106] 103: control unit

[0107] 104: PID control module

[0108] 1041: Upward PID control unit

[0109] 1042: Downward PID control unit

[0110] 11: Vehicle

[0111] S1: First step

[0112] S2: Second step

[0113] S3: Third step

[0114] S4: Fourth step

[0115] M1: Front wheel vehicle speed

[0116] M2: Rear wheel vehicle speed

[0117] M3: Preset slip critical value

[0118] M4: Torque up calculation formula

[0119] M5: Torque down calculation formula

Claims

1. A vehicle slippage control system for use in a vehicle, comprising: A front wheel speed sensor is used to measure the speed of one of the front wheels of the vehicle; A rear wheel speed sensor is used to measure the speed of one rear wheel of the vehicle; A control unit is provided with a default slip threshold value. The control unit is coupled to the front wheel speed sensor and the rear wheel speed sensor respectively, and is used to calculate a slip rate based on the front wheel speed and the rear wheel speed. A PID control module, coupled to the control unit, adjusts the vehicle's output torque according to the slip ratio. The PID control module includes: An ascending PID control unit and a descending PID control unit are provided. The ascending PID control unit has a pre-stored torque increase calculation formula, and the descending PID control unit has a pre-stored torque decrease calculation formula. When the slip ratio exceeds the preset slip threshold, the control unit triggers the PID control module to select either the rising PID control unit or the falling PID control unit to adjust the output torque according to the magnitude of the slip ratio.

2. The vehicle slippage control system as described in claim 1, characterized in that, The formula for calculating the torque increase is: Yn=Rising_P*△Xn+Rising_I*Σ△Xn+Rising_D*(△Xn-△X(n-1)) in, ΔXn is the value used to calculate the current control error. Rising_P*ΔXn is used to calculate the proportional control value; Rising_I*∑ΔXn is the integral control quantity for calculation; Rising_D*(ΔXn-ΔX(n-1)) is used to calculate the differential control quantity; The output torque Yn is obtained by adding the above control quantities together.

3. The vehicle slippage control system as described in claim 1, characterized in that, The formula for calculating the torque reduction is: Yn=Falling_P*△Xn+Falling_I*Σ△Xn+Falling_D*(△Xn-△X(n-1)) in, ΔXn is the value used to calculate the current control error. Falling_P*ΔXn is the calculated proportional control value; Falling_I*∑ΔXn is the integral control quantity for calculation; Falling_D*(ΔXn-ΔX(n-1)) is used to calculate the differential control quantity; The output torque Yn is obtained by adding the above control quantities together.

4. The vehicle slippage force control system as described in claim 1, characterized in that, The formula for calculating the slip ratio is: Slip ratio = front wheel speed / rear wheel speed; When the slip ratio exceeds the preset slip threshold, the PID control module is triggered.

5. The vehicle slippage control system as described in claim 1, characterized in that, The control unit further includes a formula for calculating a slip compensation value, wherein the slip compensation value = torque * slip value.

6. A method for implementing a vehicle slippage control system, comprising the following steps: Measure the speed of the front wheels and the speed of the rear wheels; The slip ratio is calculated after receiving the front wheel speed and the rear wheel speed through a control unit. Determine whether the slip ratio exceeds the preset slip threshold; When the slip ratio exceeds the preset slip threshold, the output torque is adjusted by selecting either the rising type PID control unit or the falling type PID control unit based on the slip ratio.

7. The method for implementing the vehicle slippage control system as described in claim 6, characterized in that, The operation of this ascending PID control unit includes the following steps: Calculate the current control error ΔXn; Calculate the proportional control value Rising_P*ΔXn; Calculate the integral control quantity Rising_I*∑ΔXn; Calculate the differential control quantity Rising_D*(ΔXn-ΔX(n-1)); The output torque Yn is obtained by adding the above control quantities together.

8. The method for implementing the vehicle slippage control system as described in claim 6, characterized in that, The descent-type PID control unit operates by including the following steps: Calculate the current control error ΔXn; Calculate the proportional control quantity Falling_P*ΔXn; Calculate the integral control quantity Falling_I*∑ΔXn; Calculate the differential control quantity Falling_D*(ΔXn-ΔX(n-1)); The output torque Yn is obtained by adding the above control quantities together.

9. The method for implementing the vehicle slippage control system as described in claim 6, characterized in that, The steps for calculating slip ratio include: Slip ratio = front wheel speed / rear wheel speed; When the slip ratio exceeds the preset slip threshold, the PID control module is triggered.

10. The method for implementing the vehicle slippage control system as described in claim 6, characterized in that, The control unit further includes a formula for calculating a slip compensation value, wherein the slip compensation value = torque * slip value.

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