Vehicle control device

Abstract

To provide a control device of a vehicle, that can maximize the total efficiency.SOLUTION: A control device of a vehicle is a control device of a vehicle with a plurality of driving wheels. The control device calculates a slip rate of each driving wheel on the basis of vehicle body speed and wheel speed, and determines a slip rate of each driving wheel so as to maximize the total efficiency expressed by the slip rate of each driving wheel and a wheel load of each driving wheel, and then, determines a torque distribution of each driving wheel on the basis of the determined slip rate of each driving wheel.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a control device for a vehicle. [Background technology]

[0002] Patent Document 1 discloses a vehicle control device that distributes torque command values for multiple motors so as to optimize efficiency. The technology disclosed in Patent Document 1 determines the torque of each motor so as to maximize overall energy efficiency (hereinafter referred to as "overall efficiency") based on the total torque command value, the torque distribution value of each motor, the drive system efficiency of each motor, and the running system efficiency of each drive wheel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4965751 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology disclosed in Patent Document 1 does not take into consideration the efficiency between the drive wheels (tires) and the road surface, so there is a risk that the overall efficiency cannot be maximized.

[0005] The present disclosure has been made in view of the above, and aims to provide a vehicle control device that can maximize overall efficiency. [Means for solving the problem]

[0006] The vehicle control device according to the present disclosure is a control device for a vehicle having a plurality of drive wheels, and the control device calculates the slip ratio of each drive wheel based on the vehicle speed and wheel speed, determines the slip ratio of each drive wheel so as to maximize the overall efficiency represented by the slip ratio of each drive wheel and the wheel load of each drive wheel, and determines the torque distribution of each drive wheel based on the determined slip ratio of each drive wheel. [Effects of the Invention]

[0007] According to the present disclosure, overall efficiency can be maximized by reflecting the efficiency between the drive wheels and the road surface. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a control device for a vehicle according to an embodiment. [Figure 2] FIG. 2 is a graph showing the relationship between slip ratio, wheel load, and driving force. [Figure 3] FIG. 3 is a graph showing the relationship between slip ratio, wheel load, and torque. [Figure 4] FIG. 4 is a flowchart showing the flow of a vehicle control method executed by the vehicle control device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A vehicle control device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially the same.

[0010] (Vehicle control device) A vehicle control device according to an embodiment will be described with reference to Fig. 1. As shown in Fig. 1, a vehicle 1 for realizing this embodiment includes a control device 10 and a plurality of drive wheels 20. Note that Fig. 1 illustrates only the components of the vehicle 1 that are necessary for explaining this embodiment, and omits other components.

[0011] Examples of the vehicle 1 include a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a fuel cell electric vehicle (FCEV), and a battery electric vehicle (BEV). The vehicle 1 may be a manually driven vehicle or an automatically driven vehicle.

[0012] The control device 10 is an electronic control unit (ECU) whose main components are a microcomputer including a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and executes various programs. By executing the various programs, the control device 10 comprehensively controls the operation of various components mounted on the vehicle 1. Furthermore, the control device 10 functions as an information acquisition unit 11, a slip ratio determination unit 12, and a torque calculation unit 13 through the execution of the various programs.

[0013] The information acquisition unit 11 acquires information necessary for calculating the slip ratio and torque of each drive wheel 20. Specifically, the information acquisition unit 11 acquires information such as the vehicle speed [m / s], the wheel speed [m / s] of each drive wheel 20, the wheel load [N] of each drive wheel 20, the tire rolling radius [m], the required driving force, and road surface characteristics. This information may be acquired via a sensor or the like provided on the vehicle 1, or may be estimated by other means.

[0014] The slip ratio determination unit 12 calculates the slip ratio of each drive wheel 20 based on the vehicle speed of the vehicle 1 and the wheel speed of each drive wheel 20. Specifically, the slip ratio determination unit 12 calculates the slip ratio of each drive wheel 20 based on the tire rolling radius r, the wheel speed ω of the drive wheel n, as shown in the following equation (1): n , vehicle speed V, slip ratio S of drive wheel n n Calculate.

[0015]

number

[0016] Furthermore, when calculating the slip ratio of each drive wheel 20, the slip ratio determination unit 12 determines the slip ratio of each drive wheel 20 so that the overall efficiency, which is expressed by the slip ratio and wheel load of each drive wheel 20, is maximized. Specifically, this overall efficiency η is calculated by multiplying the driving force F of the drive wheel n by η as shown in the upper right-hand side of the following equation (2): n , vehicle speed V, torque T of drive wheel n n , the wheel speed ω of the driving wheel n n Furthermore, the upper right-hand side of the following formula (2) can be transformed into the lower right-hand side using the above formula (1).

[0017]

number

[0018] Here, the driving force (traction force) F of the drive wheels 20 can be expressed by the slip ratio S and wheel load W of the drive wheels 20, for example, as shown in Figure 2. Similarly, the torque T of the drive wheels 20 can be expressed by the slip ratio S and wheel load W of the drive wheels 20, for example, as shown in Figure 3. Therefore, the driving force and torque of each drive wheel 20 are determined based on the slip ratio and wheel load of each drive wheel 20.

[0019] The wheel load of each drive wheel 20 is usually automatically determined based on the posture of the vehicle 1. Therefore, the slip ratio determination unit 12 determines the required driving force F trg Under these conditions, the slip ratio of each drive wheel 20 shown in the above formula (1) is calculated so that the overall efficiency η of the above formula (2) is maximized. Note that the slip ratio determination unit 12 may, for example, obtain in advance the slip ratio of each drive wheel 20 that maximizes the overall efficiency η and create a map, and determine the slip ratio of each drive wheel 20 based on this map.

[0020] The torque calculation unit 13 calculates the torque of each drive wheel 20 based on the slip ratio of each drive wheel 20 determined by the slip ratio determination unit 12. In this way, the torque calculation unit 13 determines the torque distribution of each drive wheel 20.

[0021] (Vehicle control method) A vehicle control method executed by the vehicle control device according to the embodiment will be described with reference to FIG.

[0022] First, the information acquisition unit 11 acquires the required driving force F trg (Step S1). Then, the information acquisition unit 11 reads the road surface characteristics (Step S2). Then, the information acquisition unit 11 reads the wheel load W of each drive wheel 20. n is read (step S3).

[0023] Next, the slip ratio determination unit 12 uses the above formulas (1) and (2) to determine the required driving force F trg Under these conditions, the slip ratio of each drive wheel 20 that maximizes the overall efficiency η is determined (step S4). Next, the torque calculation unit 13 calculates the torque of each drive wheel 20 from the slip ratio of each drive wheel 20 (step S5). This completes the process.

[0024] Here, the vehicle's driving energy is transmitted in the following order: power source, motor, drive wheels (tires), and road surface, so the overall efficiency cannot be maximized unless the efficiency between the drive wheels and the road surface is also taken into consideration.In particular, in an environment where the road surface is slippery, the driving force of the drive wheels is not transmitted directly to the road surface.

[0025] Therefore, in the vehicle control device according to the embodiment, in a vehicle 1 having a plurality of drive wheels 20, the slip ratio and torque distribution of each drive wheel 20 that maximizes the overall efficiency is determined taking into consideration the efficiency between the drive wheels 20 and the road surface. That is, the vehicle control device according to the embodiment can maximize the overall efficiency by optimizing the slip ratio of each drive wheel 20, taking into account the efficiency between the drive wheels 20 and the road surface.

[0026] Further advantages and modifications will readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0027] 1 vehicle 10 Control device 11 Information acquisition department 12 Slip ratio determination unit 13 Torque calculation section 20 drive wheels

Claims

[Claim 1] A control device for a vehicle having a plurality of drive wheels, The control device a slip ratio determination process for determining the slip ratio of each drive wheel based on the vehicle speed and the wheel speed so as to satisfy the required driving force of the vehicle and maximize the overall efficiency represented by the slip ratio of each drive wheel and the wheel load of each drive wheel; a torque calculation process for determining torque distribution to each drive wheel based on the determined slip ratio of each drive wheel; and The slip ratio determination process calculates the slip ratio S n of each drive wheel shown in the following formula (1) so that the overall efficiency η of the following formula (2) is maximized under the condition of the required driving force F trg . Vehicle control device. [Equation 1] [Equation 2]

Images