Torque distribution method for wheel
By accurately calculating and updating the torque distribution rate and target torque of each wheel, combined with the wheel torque limit, the problem of the existing torque distribution system being inaccurate in judging the vehicle status is solved, achieving more accurate torque control and a larger safety margin. .
Patent Information
- Application Number
- CN202310884019.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-18
- Publication Date
- 2025-01-21
AI Technical Summary
The existing torque distribution system has inaccurate problems when judging the vehicle's status, resulting in inaccurate torque control, torque loss, sudden torque change, wheel slippage, insufficient rescue capabilities, and insufficient safety boundaries.
By obtaining the target driving torque and target yaw torque of the vehicle, the torque distribution rate and target torque of each wheel are calculated, and updated based on the wheel torque limit to accurately control the driving torque and yaw torque of each wheel.
A more accurate torque control is achieved, the torque loss is reduced, the wheel slipping is reduced, the security boundary is expanded, and the rescue capacity is enhanced.
Smart Images
Figure CN119329322A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of vehicles, and more particularly to a torque distribution method for a vehicle. Background Art
[0002] Figure 1 The diagram is a schematic diagram of a vehicle with a distributed drive system. The distributed drive system includes a wheel hub motor or a wheel side motor. Figure 1 As shown, a vehicle with a distributed drive system includes four wheels 1 and four independent motors 2. The motor 2 can be a hub motor or a wheel-side motor. Each motor 2 is directly connected to a wheel 1 of the vehicle. The target torque of each motor 2 is controlled by a powertrain control unit 3 (PCU, Powertrain control unit).
[0003] Currently, there is no differential unit between the wheels in vehicles with wheel hub drive systems, so the distributed drive system usually uses the torque vector distribution function of the torque vector distribution system to realize the virtual differential function between the wheels. The torque vector distribution function can also realize multiple driving modes and even realize part of the body steady-state electronic control function.
[0004] The existing torque distribution system judges different vehicle states to intervene in wheel torque by considering various input parameters, such as vehicle speed, wheel steering angle, wheel speed, torque limit, torque and speed direction, etc. The vehicle state may include, for example, driving, braking, energy recovery, vehicle instability, etc. However, since the vehicle weight, center of gravity position, tire and road parameters are all changing, there is a problem of inaccurate judgment when using these input parameters to judge the vehicle state. As a result, the existing torque distribution system will have problems such as inaccurate torque control, torque loss, torque mutation, wheel slippage, insufficient rescue capability, and insufficient safety margin.
[0005] Therefore, a torque distribution method that can more accurately control the torque is needed. Summary of the invention
[0006] One object of the present invention is to provide a torque distribution method capable of more accurately controlling torque. Another object of the present invention is to provide a torque distribution method capable of reducing torque loss. Another object of the present invention is to provide a torque distribution method capable of reducing wheel slip. Another object of the present invention is to provide a torque distribution method capable of avoiding or reducing torque mutation.
[0007] One aspect of the present invention provides a torque distribution method for wheels, comprising the following steps: an acquisition step for acquiring a target driving torque and a target yaw torque of a vehicle; a torque distribution rate calculation step for calculating a first shaft torque distribution rate of a first shaft of the vehicle; a first shaft target torque calculation step for calculating the first shaft target driving torque and the first shaft target yaw torque according to the first shaft torque distribution rate; a first shaft wheel torque calculation step for calculating a first left wheel driving torque of a first left wheel connected to the first shaft and a first right wheel driving torque of a first right wheel connected to the first shaft according to the first shaft target driving torque and the first shaft target yaw torque; a second shaft target torque calculation step for calculating a second shaft target driving torque and a second shaft target yaw torque of a second shaft of the vehicle according to the first shaft target driving torque and the first shaft target yaw torque; a second shaft wheel torque calculation step for calculating a second left wheel driving torque of a second left wheel connected to the second shaft and a second right wheel driving torque of a second right wheel connected to the second shaft according to the second shaft target driving torque and the second shaft target yaw torque; a torque output step for outputting the first left wheel driving torque, the first right wheel driving torque, the second left wheel driving torque, and the second right wheel driving torque.
[0008] According to certain embodiments of the present invention, the torque distribution method further includes, after the first axle wheel torque calculation step and before the second axle target torque calculation step: a first axle wheel torque updating step, for determining whether the calculated first left wheel drive torque and the calculated first right wheel drive torque are within the corresponding wheel torque limit range, so as to update the first left wheel drive torque and update the first right wheel drive torque.
[0009] According to certain embodiments of the present invention, the torque distribution method further includes, after the second axle wheel torque calculation step, a second axle wheel torque updating step, for determining whether the calculated second left wheel driving torque and the calculated second right wheel driving torque are within the corresponding wheel torque limit range, so as to update the second left wheel driving torque and update the second right wheel driving torque.
[0010] According to certain embodiments of the present invention, the torque distribution method further includes, after the first-axle wheel torque updating step: a first-axle torque updating step for updating the first-axle target driving torque and updating the first-axle target yaw torque based on the updated first left-side wheel driving torque and the updated first right-side wheel driving torque, wherein the second-axle target torque calculation step includes: calculating the second-axle target driving torque and the second-axle target yaw torque based on the updated first-axle target driving torque and the updated first-axle target yaw torque.
[0011] According to certain embodiments of the present invention, the torque distribution method further includes, after the second-axle wheel torque calculation step: a second-axle torque updating step, for updating the second-axle target driving torque and updating the second-axle target yaw torque based on the updated second left-side wheel torque and the updated second right-side wheel torque; a first-axle torque re-updating step, for re-updating the first-axle target driving torque and re-updating the first-axle target yaw torque based on the updated second-axle target driving torque and the updated second-axle target yaw torque; and a first-axle wheel torque re-calculating step, for recalculating the first left-side wheel driving torque and recalculating the first right-side wheel driving torque based on the re-updated first-axle target driving torque and the re-updated first-axle target yaw torque.
[0012] According to certain embodiments of the present invention, the torque distribution method further includes, after the step of recalculating the first axle wheel torque, a step of re-updating the first axle wheel torque, determining whether the recalculated first left wheel driving torque and the recalculated first right wheel driving torque are within the corresponding wheel torque range, so as to re-update the first left wheel driving torque and re-update the first right wheel driving torque.
[0013] According to certain embodiments of the present invention, the torque distribution method also includes the following steps: calculating the conversion coefficient of the wheel yaw torque and the wheel driving torque of each wheel; wherein, the first left wheel driving torque and the first right wheel driving torque are calculated based on the first axis target driving torque, the first axis target yaw torque and the conversion coefficient; wherein, the second left wheel driving torque and the second right wheel driving torque are calculated based on the second axis target driving torque, the second axis target yaw torque and the conversion coefficient.
[0014] According to some embodiments of the present invention, the first left wheel driving torque and the first right wheel driving torque are calculated using the following formula:
[0015] T1 FL =(T1 FrontAxle *Fac FR -Y1 FrontAxle ) / (Fac FR -Fac FL ),
[0016] T1 FR =(T1 FrontAxle *Fac FL -Y1 FrontAxle ) / (Fac FL -Fac FR ),
[0017] Among them, T1 FL represents the first left wheel driving torque, T1 FRIndicates the first right wheel driving torque, T1 FrontAxle Indicates the target driving torque of the first axis, Y1 FrontAxle represents the target yaw torque of the first axis, Fac FL represents a conversion coefficient between the first left wheel driving torque of the first left wheel and the first left wheel yaw torque, and Fac FR Indicates a conversion coefficient between a first right-side wheel driving torque of the first right-side wheel and a first right-side wheel yaw torque.
[0018] According to some embodiments of the present invention, the second left wheel torque and the second right wheel torque are calculated using the following formula:
[0019] T1 RL =(T1 RearAxle *Fac RR -Y1 RearAxle ) / (Fac RR -Fac RL ),
[0020] T1 RR =(T1 RearAxle *Fac RL -Y1 RearAxle ) / (Fac RL -Fac RR ),
[0021] Among them, T1 RL Indicates the second left wheel driving torque, T1 RR Indicates the second right wheel driving torque, T1 RearAxle Indicates the target driving torque of the second axis, Y1 RearAxle represents the target yaw torque of the second axis, Fac RL represents a conversion coefficient between the second left wheel driving torque of the second left wheel and the second left wheel yaw torque, and Fac RR Indicates a conversion coefficient between the second right wheel driving torque of the second right wheel and the second right wheel yaw torque.
[0022] One aspect of the present invention provides a torque distribution device for executing a torque distribution method according to an embodiment of the present invention.
[0023] According to the torque distribution method of the embodiment of the present invention, the torque can be distributed between the front axle and the rear axle according to the wheel load, thereby reducing wheel slip, especially in the case of rapid acceleration and rapid deceleration. In addition, the torque distribution method can more accurately control the torque output to each wheel according to the wheel torque limit, so that the yaw torque and drive torque of the vehicle can be more accurately controlled, avoiding or reducing wheel slip and expanding the safety margin. In addition, the torque can be more accurately distributed between the two axles, thereby reducing torque loss and enhancing rescue capabilities. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 is a schematic diagram of a vehicle having a wheel hub drive system.
[0025] Figure 2 is a schematic diagram of a vehicle according to some embodiments of the present invention.
[0026] Figure 3 is a schematic flow chart of a torque distribution method according to some embodiments of the present invention.
[0027] Figure 4 is a schematic diagram of a vehicle according to some embodiments of the present invention.
[0028] Figure 5 is a schematic flow chart of a torque distribution method according to some embodiments of the present invention.
[0029] Figure 6 is a schematic flow chart of a torque distribution method according to some embodiments of the present invention. DETAILED DESCRIPTION
[0030] Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings. The following detailed description and the accompanying drawings are used to exemplarily illustrate the principles of the present invention, and the present invention is not limited to the preferred embodiments described. The scope of the present invention is defined by the claims. The present invention is now described in detail with reference to exemplary embodiments, and some embodiments are illustrated in the accompanying drawings. The following description is made with reference to the accompanying drawings, and unless otherwise indicated, the same reference numerals in different drawings represent the same or similar elements. The schemes described in the following exemplary embodiments do not represent all schemes of the present invention. On the contrary, these schemes are merely examples of systems and methods of various aspects of the present invention involved in the appended claims.
[0031] The present invention provides a torque distribution method and a torque distribution device for a four-wheel distributed drive vehicle and a vehicle comprising the torque distribution device. In an exemplary embodiment, the vehicle is a hub drive vehicle or a wheel side drive vehicle.
[0032] Figure 2 is a schematic diagram of a vehicle according to some embodiments of the present invention. Figure 2As shown, the vehicle includes a first shaft 10, a second shaft 20, a first left wheel 31, a first right wheel 32, a second left wheel 33, and a second right wheel 34. The first left wheel 31 and the first right wheel 32 are connected to the first shaft 10, and the second left wheel 33 and the second right wheel 34 are connected to the second shaft 20. Thus, the first left wheel 31 is a left front wheel (FL), the first right wheel 32 is a right front wheel (FR), the second left wheel 33 is a left rear wheel (RL), and the second right wheel 34 is a right rear wheel (RR). It should be understood that the first shaft 10 and the second shaft 20 may be physical shafts, or may be virtual shafts, that is, the first shaft 10 and the second shaft 20 may only represent the axis for positioning the front wheels and the rear wheels without a physical connection with the wheels.
[0033] like Figure 2 As shown, the vehicle further includes four motors 41, 42, 43, 44, which are respectively connected to wheels 31, 32, 33, 34. Motors 41, 42, 43, 44 can be hub motors or wheel-side motors. Motor 41 is used to generate torque for the first left wheel 31, motor 42 is used to generate torque for the first right wheel 32, motor 43 is used to generate torque for the second left wheel 33, and motor 44 is used to generate torque for the second right wheel 34.
[0034] like Figure 2 As shown, the vehicle further includes a torque distribution device 50, which is connected to the motors 41, 42, 43, 44 respectively to control the torque output of these motors. The torque distribution device 50 can perform the torque distribution method according to the embodiment of the present invention.
[0035] Figure 3 is a schematic flow chart of a torque distribution method according to some embodiments of the present invention. Figure 2 and Figure 3 A torque distribution method according to certain embodiments of the present invention is described.
[0036] In step S110, the target driving torque T and target yaw torque Y of the vehicle are obtained. The target driving torque T represents the driving torque that the four wheels of the vehicle are expected to generate together. The target yaw torque Y represents the yaw torque that the four wheels of the vehicle are expected to generate together. In some embodiments, the target driving torque T can be input from a vehicle control unit (VCU, not shown) of the vehicle. In some embodiments, the target yaw torque Y can be determined by an independent target yaw torque determination module (not shown). The target yaw torque determination module can determine the target yaw torque Y by the vehicle motion state (longitudinal acceleration, lateral acceleration, etc.), slope, accelerator pedal angle, brake pedal angle, etc.
[0037] In step S120, the first axle torque distribution ratio R of the vehicle is calculated. FrontAxleSpecifically, the first axle torque distribution rate R of the vehicle can be calculated according to the load of each wheel of the vehicle. FrontAxle In an exemplary embodiment, the first shaft torque distribution ratio R FrontAxle It can be calculated according to the following formula (1):
[0038] R FrontAxle = (WL FL + WL FR ) / (WL FL + WL FR + WL RL + WL RR ) (1).
[0039] In the above formula (1), WL FL represents the load of the first left wheel 31, WL FR represents the load of the first right wheel 32, WL RL represents the load of the second left wheel 33, WL RR represents the load of the second right wheel 34. In some embodiments, the load of the wheel can be determined by vehicle speed, vehicle acceleration, vehicle posture, etc.
[0040] Thus, the torque distribution apparatus according to the embodiment of the present invention can distribute torque between the front axle and the rear axle according to the wheel load.
[0041] In step S130, according to the first torque distribution ratio R FrontAxle , calculate the first axis target driving torque T1 FrontAxle and the first axis target yaw torque Y1 FrontAxle . Target drive torque of the first axis T1 FrontAxle represents the target driving torque that is expected to be achieved by the first left wheel 31 and the first right wheel 32 connected to the first shaft 10, and the first shaft target yaw torque Y1 FrontAxle It represents the target yaw torque that is desired to be achieved by the first left wheel 31 and the first right wheel 32 together.
[0042] In some embodiments, the first axis target driving torque T1 FrontAxle and the first axis target yaw torque Y1 FrontAxle It can be calculated according to the following formulas (2-1) and (2-2):
[0043] T1 FrontAxle =T*R FrontAxle (2-1);
[0044] Y1 FrontAxle =Y*R FrontAxle (2-2).
[0045] In step S140, according to the first axis target driving torque T1 FrontAxle and the first axis target yaw torque Y1 FrontAxle , calculate the first left wheel driving torque T1 of the first left wheel 31 FL and a first right wheel driving torque T1 of the first right wheel 32 FR In some embodiments, the first left wheel driving torque T1 FL and the first right wheel driving torque T1 FR It can be calculated according to the following formulas (3-1) and (3-2):
[0046] T1 FL =(T1 FrontAxle *Fac FR -Y1 FrontAxle ) / (Fac FR -Fac FL ) (3-1);
[0047] T1 FR =(T1 FrontAxle *Fac FL -Y1 FrontAxle ) / (Fac FL -Fac FR ) (3-2).
[0048] In the above formulas (3-1) and (3-2), Fac FL The first left wheel driving torque T1 of the first left wheel 31 is represented by FL and the first left wheel yaw torque Y1 FL Conversion coefficient between FL =T1 FL *Fac FL ;Fac FR The first right wheel driving torque T1 of the first right wheel 32 is represented by FR and the first right wheel yaw torque Y1 FR Conversion coefficient between FR =T1 FR *Fac FR .
[0049] In an exemplary embodiment, the torque distribution method may further include the following steps: calculating a conversion coefficient Fac between the wheel driving torque and the wheel yaw torque of the wheel. In some embodiments, the conversion coefficients Fac of the four wheels 31, 32, 33, and 34 may be calculated by the following formulas (4-1) to (4-4), respectively:
[0050] Fac FL =(sinβ*a-cosβ*B / 2) / R (4-1);
[0051] Fac FR =(sinβ*a+cosβ*B / 2) / R (4-2);
[0052] Fac RL =(-sinβ*b+cosβ*B / 2) / R (4-3);
[0053] Fac RR =(sinβ*b+cosβ*B / 2) / R (4-4).
[0054] In the above formulas (4-3) and (4-4), Fac RL The second left wheel driving torque T1 of the second left wheel 33 is represented by RL and the second left wheel yaw torque Y1 RL Conversion coefficient between RL =T1 RL *Fac RL ;Fac RR The second right wheel driving torque T1 of the second right wheel 34 is represented by RR and the second right wheel yaw torque Y1 RR Conversion coefficient between RR =T1 RR *Fac RR .
[0055] Figure 4 is a schematic diagram of a vehicle according to some embodiments of the present invention. In addition, in the above formulas (4-1) to (4-4), if Figure 4 As shown, β represents the wheel steering angle, a represents the distance from the center of mass of the vehicle to the first axis, b represents the distance from the center of mass of the vehicle to the second axis, B represents the distance between the two wheels connected to the first axis, and R (not shown) represents the radius of the wheel.
[0056] Therefore, the first shaft target driving torque T1 of the vehicle FrontAxle and the first axis target yaw torque Y1 FrontAxle It can be expressed by the following equation group (5):
[0057]
[0058] By solving the above equation group (5), the above formulas (3-1) and (3-2) can be obtained, so that the first left wheel driving torque T1 can be calculated: FL and the first right wheel driving torque T1 FR .
[0059] In step S150, the second axis target driving torque T1 is calculated.RearAxle and the second axis target yaw torque Y1 RearAxle In an exemplary embodiment, according to the first axis target driving torque T1 FrontAxle and the first axis target yaw torque Y1 FrontAxle , calculate the second axis target driving torque T1 RearAxle and the second axis target yaw torque Y1 RearAxle In some embodiments, the second shaft target driving torque T1 RearAxle and the second axis target yaw torque Y1 RearAxle It can be calculated by the following formulas (6-1) and (6-2):
[0060] T1 RearAxle =T–T1 FrontAxle (6-1);
[0061] Y1 RearAxle =Y–Y1 FrontAxle (6-2).
[0062] In step S160, according to the second shaft target driving torque T1 RearAxle and the second axis target yaw torque Y1 RearAxle , calculate the second left wheel driving torque T1 of the second left wheel 33 RL and a second right wheel driving torque T1 of the second right wheel 34 RR In some embodiments, the second left wheel driving torque T1 RL and the second right wheel driving torque T1 RR It can be calculated according to the following formulas (7-1) and (7-2):
[0063] T1 RL =(T1 RearAxle *Fac RR -Y1 RearAxle ) / (Fac RR -Fac RL ) (7-1);
[0064] T1 RR =(T1 RearAxle *Fac RL -Y1 RearAxle ) / (Fac RL -Fac RR ) (7-2).
[0065] In the above formulas (7-1) and (7-2), Fac RL The second left wheel driving torque T1 RL and the second left wheel yaw torque Y1 RL Conversion coefficient betweenRL =T1 RL *Fac RL ;Fac FR The second right wheel driving torque T1 RR and the second right wheel yaw torque Y1 RR Conversion coefficient between RR =T1 RR *Fac RR In an exemplary embodiment, the conversion coefficient Fac RL and Facebook RR It can be calculated using the above formulas (4-3) and (4-4).
[0066] Therefore, the second shaft target driving torque T1 of the vehicle RearAxle and the second axis target yaw torque Y1 RearAxle It can be expressed by the following equation group (8):
[0067]
[0068] By solving the above equation group (8), the above formulas (7-1) and (7-2) can be obtained, so that the second left wheel driving torque T1 can be calculated: RL and the second right wheel driving torque T1 RR .
[0069] In step S190, the first left wheel driving torque T1 is output. FL , first right wheel driving torque T1 FR , the second left wheel driving torque T1 RL and the second right wheel driving torque T1 RR Thus, each wheel driving torque can be output to the corresponding motor, so that the motor can drive the corresponding wheel according to the wheel driving torque.
[0070] In some cases, the wheel drive torque calculated in the above step S140 or S160 may not be realized, for example, exceeding the maximum torque of the wheel. To this end, the torque distribution method according to the embodiment of the present invention may also set a torque limit factor to determine whether the calculated wheel drive torque can be realized. A detailed description will be described below with reference to the accompanying drawings.
[0071] Figure 5 is a schematic flow chart of a torque distribution method according to some embodiments of the present invention. Figure 2 and Figure 5 A torque distribution method according to certain embodiments of the present invention is described. Figure 5 The steps S110 to S140 and S150 to S160 of the torque distribution method shown in FIG. Figure 3Steps S110 to S140, and S150 to S160 of the torque distribution method shown in FIG. 1 are the same as those in FIG. 1 , and will not be described in detail herein. Figure 3 The differences in the torque distribution methods shown in Figure 4 The torque distribution method shown in .
[0072] In an exemplary embodiment, the torque distribution method includes the following steps: setting the torque limiting factor of the wheel. The torque limiting factor of the wheel may include: the maximum torque of the wheel and the minimum torque of the wheel. The maximum torque of the first left wheel 31 is represented by T FLmax , the minimum torque is expressed as T FLmin The maximum torque of the first right wheel 32 is represented by T FRmax , the minimum torque is expressed as T FRmin The maximum torque of the second left wheel 33 is expressed as T RLmax , the minimum torque is expressed as T RLmin The maximum torque of the second right wheel 34 is expressed as T RRmax , the minimum torque is expressed as T RRmin In some embodiments, the torque limiting factors of the wheels may also include: the motor capacity of the motor connected to the wheels, the failure of the motor, the wheel slip ratio control (controlling the slip ratio by limiting the torque of the motor), etc.
[0073] The torque distribution method calculates the first left wheel driving torque T1 in step S140. FL and the first right wheel driving torque T1 FR Afterwards, the method may include step S141: determining the calculated first left wheel driving torque T1 FL and the calculated first right wheel driving torque T1 FR Is it within the corresponding wheel torque limit range to update the first left wheel driving torque T1 FL And update the first right wheel driving torque T1 FR . In an exemplary embodiment, the wheel torque limit range represents a range consisting of a maximum torque and a minimum torque of the wheel. In this article, "update" means comparing the calculated wheel drive torque with the torque limit range of the wheel to determine the wheel drive torque that can actually be achieved, and then determine the single-axis drive torque and single-axis yaw torque that can actually be achieved. Specifically, when the calculated wheel drive torque exceeds the torque limit range of the wheel, the wheel drive torque will be updated to the upper limit value (maximum torque) or the lower limit value (minimum torque) of the torque limit range.
[0074] In some embodiments, the first left wheel driving torque T1 may be updated by the following formulas (9-1) and (9-2): FL and update the first right wheel driving torque T1FR :
[0075] T1 FL =max(T FLmin ,min(T FLmax ,T1 FL )) (9-1);
[0076] T1 FR =max(T FRmin ,min(T FRmax ,T1 FR )) (9-2).
[0077] In the above formulas (9-1) and (9-2), T FLmax represents the maximum torque of the first left wheel 31, T FLmin represents the minimum torque of the first left wheel 31; T FRmax represents the maximum torque of the first right wheel 32, T FRmin represents the minimum torque of the first right wheel 32 .
[0078] Therefore, it can be determined that the first left wheel driving torque T1 calculated by formulas (3-1) and (3-2) is FL and the first right wheel driving torque T1 FR For example, if the calculated first left wheel driving torque T1 FL Greater than the maximum torque T of the first left wheel 31 FLmax , then the first left wheel 31 can only use its maximum torque T FLmax as the maximum torque produced.
[0079] The torque distribution method may further include, after step S141, step S142: according to the updated first left wheel driving torque T1 FL and update the first right wheel driving torque T1 FR , update the first axis target driving torque T1 FrontAxle And update the first axis target yaw torque Y1 FrontAxle In some embodiments, the first axis target driving torque T1 can be updated by the following formulas (10-1) and (10-2): FrontAxle And update the first axis target yaw torque Y1 FrontAxle :
[0080] T1 FrontAxle =T1 FL +T1 FR (10-1);
[0081] Y1 FrontAxle =T1 FL *FacFL +T1 FR *Fac FR (10-2).
[0082] Therefore, the torque distribution method according to the embodiment of the present invention can be used in step S150 according to the updated first-axis target driving torque T1 FrontAxle and the updated first axis target yaw torque Y1 FrontAxle , calculate the second axis target driving torque T1 RearAxle and the second axis target yaw torque Y1 RearAxle This allows the torque to be distributed more accurately to one axle, based on the torque that can actually be achieved by the two wheels connected to the other axle.
[0083] The torque distribution method calculates the second left wheel driving torque T1 in step S160. RL and the second right wheel driving torque T1 RR Afterwards, the process may include step S161: determining the second left wheel driving torque T1 RL and the second right wheel driving torque T1 RR Is it within the corresponding wheel torque limit range to update the second left wheel driving torque T1 RL And update the second right wheel driving torque T1 RR In an exemplary embodiment, as described above, the wheel torque limit range represents a range consisting of a maximum torque and a minimum torque of the wheel.
[0084] In some embodiments, the second left wheel driving torque T1 may be updated by the following formulas (11-1) and (11-2): RL and update the second right wheel drive torque T1 RR :
[0085] T1 RL =max(T RLmin ,min(T RLmax ,T1 RL )) (11-1);
[0086] T1 RR =max(T RRmin ,min(T RRmax ,T1 RR )) (11-2).
[0087] In the above formulas (11-1) and (11-2), T RLmax represents the maximum torque of the second left wheel 33, T RLmin represents the minimum torque of the second left wheel 33; T RRmax represents the maximum torque of the second right wheel 34, TRRmin represents the minimum torque of the second right wheel 34 .
[0088] Therefore, it can be determined that the second left wheel driving torque T1 calculated by formulas (7-1) and (7-2) is RL and the second right wheel driving torque T1 RR For example, if the calculated second left wheel driving torque T1 RL Greater than the maximum torque T of the second left wheel 33 RLmax , then the second left wheel 33 can only use its maximum torque T RLmax as the maximum torque produced.
[0089] exist Figure 5 In the torque distribution method shown in FIG. 1 , in step S190, the first left wheel driving torque T1 can be output according to the updated wheel driving torque. FL and the first right wheel driving torque T1 FR , the second left wheel driving torque T1 RL and the second right wheel driving torque T1 RR .
[0090] In this way, the torque output to each wheel can be more accurately controlled according to the wheel torque limit, so that the vehicle's yaw torque and drive torque can be more accurately controlled, wheel slip can be avoided or reduced, and the safety margin can be expanded.
[0091] In some cases, the sum of the wheel drive torques output in the above S190 may still not meet the target drive torque and the target yaw torque. At this time, if at least one wheel has not reached its maximum torque, the torque distribution method can also update the wheel drive torque again. This will be described in detail below with reference to the accompanying drawings.
[0092] Figure 6 is a schematic flow chart of a torque distribution method according to some embodiments of the present invention. Figure 2 and Figure 6 A torque distribution method according to certain embodiments of the present invention is described. Figure 6 Steps S110 to S161 of the torque distribution method shown in FIG. Figure 5 The steps S110 to S161 of the torque distribution method shown in FIG. 1 are the same as those in FIG. 1 and will not be described in detail here. Figure 5 The differences in the torque distribution methods shown in Figure 6 The torque distribution method shown in .
[0093] In step S171, according to the updated second left wheel driving torque T1 RL and updated second right wheel drive torque T1 RR, to update the second axis target driving torque T1 RearAxle And update the second axis target yaw torque Y1 RearAxle In some embodiments, the second axis target driving torque T1 can be updated by the following formulas (12-1) and (12-2): RearAxle And update the second axis target yaw torque Y1 RearAxle :
[0094] T1 RearAxle =T1 RL +T1 RR (12-1);
[0095] Y1 RearAxle =T1 RL *Fac RL +T1 RR *Fac RR (12-2).
[0096] In step S172, according to the updated second-axis target driving torque T1 RearAxle and the updated second axis target yaw torque Y1 RearAxle , update the first axis target driving torque T1 again RearAxle And update the first axis target yaw torque Y1 again RearAxle In some embodiments, the first axis target driving torque T1 can be updated again by the following formulas (13-1) and (13-2): RearAxle And update the first axis target yaw torque Y1 again RearAxle :
[0097] T1 FrontAxle =T–T1 RearAxle (13-1);
[0098] Y1 FrontAxle =Y–Y1 RearAxle (13-2).
[0099] In step S173, according to the first axis target driving torque T1 which is updated again, RearAxle and the updated first axis target yaw torque Y1 RearAxle , calculate the first left wheel driving torque T1 again FL and the first right wheel driving torque T1 FR In some embodiments, the first left wheel driving torque T3 FL and the first right wheel driving torque T3 FR It can be calculated again according to the above formulas (3-1) and (3-2).
[0100] In step S174, the first left wheel driving torque T1 calculated again is determined.FL and the first right wheel driving torque T1 calculated again FR Is it within the corresponding wheel torque limit range to update the first left wheel driving torque T1 again FL and update the first right wheel driving torque T1 again FR In some embodiments, the first left wheel driving torque T1 can be updated again by the above formulas (9-1) and (9-2): FL and update the first right wheel driving torque T1 again FR .
[0101] exist Figure 6 In the torque distribution method shown in FIG. 1 , in step S190, the first left wheel driving torque T1 can be output according to the updated wheel driving torque. FL and the first right wheel driving torque T1 FR , the second left wheel driving torque T1 RL and the second right wheel driving torque T1 RR .
[0102] In this way, the torque can be distributed more accurately between the two axles according to the torque that each wheel can actually achieve, so that the vehicle's yaw torque and driving torque can be more accurately controlled, torque loss can be reduced, and rescue capabilities can be enhanced.
[0103] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the configuration and method of the above-described embodiments. On the contrary, the present invention is intended to cover various modifications and equivalent configurations. In addition, although the various elements and method steps of the disclosed invention are shown in various exemplary combinations and configurations, other combinations including more or less elements or methods also fall within the scope of the present invention.
[0104] Reference numerals list
[0105] 10 first axis;
[0106] 20 Second axis;
[0107] 31 first left wheel;
[0108] 32 first right wheel;
[0109] 33 Second left wheel;
[0110] 34 second right wheel;
[0111] 41 Motor;
[0112] 42 Motor;
[0113] 43 Motor;
[0114] 44 motor;
[0115] 50 Torque distribution device.
Claims
1. A method for distributing torque to wheels, comprising the following steps: An acquisition step for acquiring a target driving torque (T) and a target yaw torque (Y) of the vehicle; The torque distribution ratio calculation step is used to calculate the first shaft torque distribution ratio (R FrontAxle ); The first shaft target torque calculation step is used to calculate the first shaft target torque according to the first shaft torque distribution ratio (R FrontAxle ), calculate the first axis target driving torque (T1 FrontAxle ) and the first axis target yaw torque (Y1 FrontAxle ); The first axle wheel torque calculation step is used to calculate the first axle wheel torque according to the first axle target driving torque (T1 FrontAxle ) and the first axis target yaw torque (Y1 FrontAxle ), calculates a first left wheel driving torque (T1 FL ) and a first right wheel driving torque (T1) of a first right wheel (32) connected to the first shaft FR ); The second shaft target torque calculation step is used to calculate the target torque of the first shaft according to the target driving torque (T1 FrontAxle ) and the first axis target yaw torque (Y1 FrontAxle ), calculate the second axis target driving torque (T1 RearAxle ) and the second axis target yaw torque (Y1 RearAxle ); The second axle wheel torque calculation step is used to calculate the wheel torque of the second axle according to the target driving torque of the second axle (T1 RearAxle ) and the second axis target yaw torque (Y1 RearAxle ), calculate the second left wheel driving torque (T1 RL ) and a second right wheel driving torque (T1) of a second right wheel (34) connected to the second shaft RR ); and The torque output step is used to output the first left wheel driving torque (T1 FL ), the first right wheel driving torque (T1 FR ), the second left wheel driving torque (T2 RL ) and the second right wheel driving torque (T2 RR ).
2. The torque distribution method according to claim 1, after the first axle wheel torque calculation step and before the second axle target torque calculation step, further comprising: The first axle wheel torque updating step is used to determine the calculated first left wheel driving torque (T1 FL ) and the calculated first right wheel driving torque (T1 FR ) is within the corresponding wheel torque limit range to update the first left wheel driving torque (T1 FL ) and updates the first right wheel driving torque (T1 FR ).
3. The torque distribution method according to claim 2, after the step of calculating the wheel torque of the second axle, further comprising: The second axle wheel torque updating step is used to determine the calculated second left wheel driving torque (T1 RL ) and the calculated second right wheel driving torque (T1 RR ) is within the corresponding wheel torque limit range to update the second left wheel driving torque (T1 RL ) and updates the second right wheel driving torque (T1 RR ).
4. The torque distribution method according to claim 3, further comprising after the first axle wheel torque updating step: The first shaft torque updating step is used to update the first left wheel driving torque (T1 FL ) and the updated first right wheel driving torque (T1 FR ), update the first axis target driving torque (T1 FrontAxle ) and update the first axis target yaw torque (Y1 FrontAxle ), The second-axis target torque calculation step includes: according to the updated first-axis target driving torque (T1 FrontAxle ) and the updated first axis target yaw torque (Y1 FrontAxle ), calculate the second axis target driving torque (T1 RearAxle ) and the second axis target yaw torque (Y1 RearAxle ).
5. The torque distribution method according to claim 4, further comprising after the step of calculating the wheel torque of the second axle: The second shaft torque updating step is used to update the second left wheel driving torque (T1 RL ) and the updated second right wheel driving torque (T1 RR ), update the second axis target driving torque (T1 RearAxle ) and update the second axis target yaw torque (Y1 RearAxle ); The first shaft torque re-updating step is used to update the second shaft target driving torque (T1 RearAxle ) and the updated second axis target yaw torque (Y1 RearAxle ), and update the first axis target driving torque (T1 FrontAxle ) and update the first axis target yaw torque (Y1 FrontAxle );and The first-axle wheel torque recalculation step is used to calculate the first-axle target driving torque (T1) according to the re-updated first-axle target driving torque (T1 FrontAxle ) and the first axis target yaw torque (Y1) updated again FrontAxle ), calculate the first left wheel driving torque (T1 FL ) and recalculate the first right wheel driving torque (T1 FR ).
6. The torque distribution method according to claim 5, further comprising, after the step of recalculating the wheel torque of the first axle: The first axle wheel torque is updated again, determining the first left wheel driving torque (T1 FL ) and the first right wheel driving torque (T1) calculated again FR ) is within the corresponding wheel torque range to update the first left wheel driving torque (T1 FL ) and update the first right wheel driving torque (T1 FR ).
7. The torque distribution method according to any one of claims 1 to 6, further comprising the steps of: calculating a conversion coefficient between the wheel yaw torque and the wheel driving torque of each wheel; in, According to the first axis target driving torque (T1 FrontAxle ) and the first axis target yaw torque (Y1 FrontAxle ) and the conversion coefficient, calculate the first left wheel driving torque (T1 FL ) and the first right wheel driving torque (T1 FR ); According to the second axis target driving torque (T1 RearAxle ) and the second axis target yaw torque (Y1 RearAxle ) and the conversion coefficient, calculate the second left wheel driving torque (T1 RL ) and the second right wheel driving torque (T1 RR ).
8. The torque distribution method according to claim 7, wherein: The first left wheel driving torque (T1) is calculated using the following formula FL ) and the first right wheel driving torque (T1 FR ): T1 FL =(T1 FrontAxle *I do FR Y1 FrontAxle ) / (I do FR -I do FL ), T1 FR =(T1 FrontAxle *I do FL Y1 FrontAxle ) / (I do FL -I do FR ), Among them, T1 FL represents the first left wheel driving torque, T1 FR represents the first right wheel driving torque, T1 FrontAxle represents the target driving torque of the first axis, Y1 FrontAxle represents the target yaw torque of the first axis, Fac FL represents the first left wheel driving torque (T1) of the first left wheel (31) FL ) and the conversion coefficient between the first left wheel yaw torque, and Fac FR represents the first right wheel driving torque (T1) of the first right wheel (32) FR ) and the conversion coefficient between the first right wheel yaw torque.
9. The torque distribution method according to claim 8, wherein: Use the following formula to calculate the second left wheel torque (T1 RL ) and the second right wheel torque (T1 RR ): T1 RL =(T1 RearAxle *I do RR Y1 RearAxle ) / (I do RR -I do RL ), T1 RR =(T1 RearAxle *I do RL Y1 RearAxle ) / (I do RL -I do RR ), Among them, T1 RL represents the second left wheel driving torque, T1 RR represents the second right wheel driving torque, T1 RearAxle represents the target driving torque of the second axis, Y1 RearAxle represents the target yaw torque of the second axis, Fac RL represents the second left wheel driving torque (T1) of the second left wheel (33) RL ) and the conversion coefficient between the yaw torque of the second left wheel, and Fac RR represents the second right wheel driving torque (T1) of the second right wheel (34) RR ) and the conversion coefficient between the yaw torque of the second right wheel. 10 . A torque distribution device, used for executing the torque distribution method according to any one of claims 1 to 9.