Driving force control device

Abstract

To perform torque control while suppressing influences on function of each part.SOLUTION: A driving force control device comprises: driving force torque correction means 11 which calculates a correction amount od driving force as an operation amount for controlling a vehicle yaw rate to a target yaw rate that is a target value thereof, and calculates a required torque value after correction, in a turning behavior of a vehicle; spring mass damping control means 12 which calculates a torque value for reducing vibration of a vehicle body; total calculation means 13 which calculates total torque that is the sum of the torque value calculated by the driving force correction means 11 and the torque value calculated by the spring mass damping control means 12; and guard processing means 14 which provides a torque upper limit of the total torque calculated by the total calculation means 13 and a power upper limit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a driving force control device for a vehicle.

Background Art

[0002] In recent years, at the initial stage of turning where the steering angle of a vehicle starts to change, a target value of yaw rate is set, and a yaw moment is calculated as an operation amount for controlling the yaw rate to the target value. Further, in a vehicle, a correction amount of a torque command value for generating a torque corresponding to the yaw moment in an internal combustion engine is calculated, and the internal combustion engine is operated so as to obtain a torque command value corrected by this correction amount.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When torque correction is performed by adding line trace control and sprung vibration control as in the control device disclosed in Patent Document 1, if the torque correction amount is large, the operating points of the motor generator and the engine may change, or the charging power to the battery may increase. Therefore, there is a desire to suppress the influence on other functions such as changes in operation and increases in charging power due to torque correction.

[0005] The present invention provides a driving force control device for a vehicle that controls torque while suppressing the influence on the functions of each part.

Means for Solving the Problems

[0006] The driving force control device according to the present invention calculates a correction amount of the driving force as an operation amount for controlling the yaw rate of the vehicle to the target yaw rate, which is the target value, in the control of the turning behavior of the vehicle, and calculates the value of the required corrected torque. It includes a driving force torque correction means, a sprung vibration control means for calculating the value of the torque for reducing the sway of the vehicle body, a total calculation means for calculating the total torque obtained by adding the value of the torque calculated by the driving force torque correction means and the value of the torque calculated by the sprung vibration control means, and a guard processing means for providing a torque upper limit and a power upper limit for the total torque calculated by the total calculation means. Thereby, it is possible to set a torque upper limit for the total torque obtained by adding the line trace control and the sprung vibration control.

Effect of the Invention

[0007] Thereby, it is possible to provide a driving force control device for a vehicle that controls torque while suppressing the influence on the functions of each part.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] Embodiment 1 Hereinafter, the driving force control device according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the configuration of the driving force control device 1 provided in a vehicle. In the following, the vehicle will be described as a hybrid vehicle including a motor generator that mainly generates driving force by electric power and an engine that mainly generates driving force by gasoline, but it is not limited thereto.

[0010] The driving force control device 1 includes a driving force torque correction means 11 for calculating a correction amount of the driving force generated in the vehicle, a sprung vibration control means 12 for calculating a correction amount for reducing the sway of the vehicle body, a total operation means 13 for adding the correction amount calculated by the driving force torque correction means 11 and the correction amount calculated by the sprung vibration control means 12, and a guard processing means 14 for performing a guard process of limiting the upper limit value of the torque totaled by the total operation means 13.

[0011] During the turning behavior control of the vehicle, the driving force torque correction means 11 calculates a correction amount related to the control of the driving force as an operation amount in order to control the yaw rate of the vehicle to a target yaw rate which is a target value. Further, the driving force torque correction means 11 calculates a value of the torque after correction necessary for realizing this correction amount of the driving force. It can be said that the driving force torque correction means 11 performs line trace control related to the running of the vehicle.

[0012] Typically, the sprung vibration control means 12 calculates a correction amount of the torque so as to reduce the sway of the vehicle body by varying the torque of the driving motor according to the unevenness of the road surface.

[0013] The total operation means 13 calculates a value obtained by adding the corrected torque necessary for generating the corrected driving force calculated by the driving force torque correction means 11 and the corrected torque corrected by the correction amount calculated by the sprung vibration control means 12. This added torque is defined as the total torque. Note that it is possible to perform torque correction of the vehicle by the total torque calculated by the total operation means 13.

[0014] The guard processing means 14 performs a guard process of providing a torque upper limit and a power upper limit for the total torque calculated by the total operation means 13 and guarding so that the lower limit of the total torque does not become lower than a predetermined value. Here, the torque with the lower limit value of the total torque restricted by the guard processing means 14 is defined as the total torque after guard.

[0015] Next, with reference to FIG. 2, an example of the operation of the driving force control device 1 will be described.

[0016] The driving force torque correction means 11 calculates the value of the torque after correction for the line tracing control (step S1). For example, the driving force torque correction means 11 calculates a yaw moment for bringing the actual vehicle yaw rate closer to the target yaw rate set according to the turn when the vehicle turns. Then, the driving force torque correction means 11 determines the driving force generated by the engine, that is, the value of the torque, so as to generate a torque corresponding to the yaw moment, and corrects the value of the torque generated by the engine.

[0017] The sprung vibration control means 12 calculates the value of the torque after correction for performing control to balance the front and rear of the vehicle (step S2). For example, the sprung vibration control means 12 calculates the force acting on the wheel center from the result of detecting the rotational speed of each wheel using a sensor that detects the rotational speed of the wheels, and estimates the sinking of the rear side of the vehicle body. When the rear part of the vehicle body is sunken, the sprung vibration control means 12 determines the value of the torque so that the torque of the motor related to the front wheels increases so that the front part of the vehicle body sinks, and corrects the driving amount of the motor.

[0018] The total calculation means 13 calculates the total torque obtained by adding the value of the torque calculated by the driving force torque correction means 11 and the value of the torque calculated by the sprung vibration control means 12 (step S3).

[0019] The guard processing means 14 limits the upper limit value for the total torque calculated by the total calculation means 13 (step S4). Here, in the guard processing by the guard processing means 14, the values of the torque upper limit and the power upper limit are limited for the total torque.

[0020] Note that the settings of the power limit and torque limit can be changed according to the running speed of the vehicle. As an example, when the running speed of the vehicle is below a predetermined speed, the upper limit of torque is set to a constant value so as to generate the maximum torque. When the running speed of the vehicle is above the predetermined speed, the upper limit of torque can be determined so that the power value is constant in consideration of the power balance. In other words, when the vehicle speed is low, the upper limit of torque is set to be constant, and as the vehicle speed increases, the upper limit of torque can be set to a lower value.

[0021] In addition, the guard processing means 14 can provide a lower limit guard so that the total torque does not fall below a predetermined value. At this time, by limiting the torque upper limit and power upper limit of the total torque within the torque range calculated by the sprung vibration control means 12, it becomes easier to provide a lower limit guard for the total torque.

[0022] Here, FIG. 3 is a diagram showing a state in which a lower limit guard is applied to the torque generated in the vehicle according to the restrictions provided by the guard processing means 14. More specifically, FIG. 3(a) is an example of the torque of the sprung vibration control in a state where the lower limit guard is set by the guard processing means 14, FIG. 3(b) is an example of the torque related to the line trace control, and FIG. 3(c) shows an example of the torque in a state where a lower limit guard is set for the total torque of the sprung vibration control and the line trace control generated in the vehicle. In FIGS. 3(a) to 3(c), the vertical axis represents torque and the horizontal axis represents time, and the time axis, which is the horizontal axis, is the common time in FIGS. 3(a) to 3(c).

[0023] As shown in FIG. 3(a), the sprung vibration control means 12 sets the sprung vibration control torque. Typically at this time, the sprung vibration control torque is set so that the magnitude of the torque changes in a sine wave shape according to the passage of time. Here, as shown in FIG. 3(a), the torque is described as changing between +15 Nm and -15 Nm.

[0024] Furthermore, as shown by the dotted line in Fig. 3(a), the guard processing means 14 can set a lower limit guard so that the value of the torque set by the on-spring vibration control means 12 does not fall below a predetermined torque.

[0025] On the other hand, as shown in Fig. 3(b), the driving force torque correction means 11 sets the torque applied to the line tracing control. At this time, the torque applied to the line tracing control is changed according to the behavior of the vehicle, and appropriately transitions between continuing the state of generating torque and continuing the state of not generating torque. Here, as shown in Fig. 3(b), the torque is 0 from time 0 sec to time 7 sec, becomes -15 Nm from time 7.5 sec to 13 sec, and then becomes 0 again after time 13.5 sec. It is assumed that these state transitions take 0.5 sec.

[0026] Fig. 3(c) shows the on-spring vibration control torque shown in Fig. 3(a), the total torque obtained by adding the torque applied to the line tracing control shown in Fig. 3(b), and the state in which the lower limit of the total torque is guarded by the guard processing means 14 at -15 Nm. The guard of the lower limit of the total torque is shown by a dotted line.

[0027] More specifically, in Fig. 3(c), from time 0 sec to 7 sec, since the torque related to the line tracing control is 0, the total torque is the same as the torque applied to the on-spring vibration control, and the torque is between +15 Nm and -15 Nm. That is, from time 0 sec to 7 sec, the torque is always in a state of -15 Nm or more, and there is no influence of the lower limit guard by the guard processing means 14.

[0028] Next, between time 7 sec and time 13.5 sec, as shown in Fig. 3(b), the torque applied to the line tracing control becomes -15 Nm from time 7.5 sec to 13 sec. Therefore, as shown in Fig. 3(c), a part of the total torque becomes less than -15 Nm.

[0029] Here, the guard processing means 14 guards so that the total torque does not fall below -15 Nm. That is, the guard processing means 14 controls the torque to be -15 Nm for the portion where the torque value of the total torque is below -15 Nm during the time period from time 7.5 sec to 13 sec when the torque applied to the line trace control is -15 Nm, and at the transition times before and after that.

[0030] In other words, in FIG. 3(c), between time 7 sec and 13.5 sec, for the portion where the torque value of the total torque is -15 Nm to -30 Nm, the guard processing means 14 can set the lower limit value of the torque to -15 Nm. That is, the guard processing means 14 can set the total torque after guard by guarding the lower limit of the torque value for a part of the total torque.

[0031] In this way, when determining the correction amount of the torque for the entire vehicle by adding together the correction amount of the torque calculated by the driving force torque correction means 11 and the correction amount of the torque calculated by the sprung vibration control means 12, the upper limit value of the torque correction and the upper limit value of the power correction can be set.

[0032] Also, by setting the upper limit value of the torque correction and the upper limit value of the power correction, it is possible to suppress the change in the operating point of the motor generator or the engine and the increase in the charging power to the battery. Furthermore, the influence on fuel consumption, the detection of failures in the OBD (on-vehicle diagnostic device), the influence on power management, etc. are suppressed, and since it is not necessary to generate extra heat, it is possible to protect the parts of each section.

[0033] Note that the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist. That is, the above description has been appropriately omitted and simplified for the sake of clarity of explanation, and those skilled in the art can easily change, add, and transform each element of the embodiment within the scope of the present invention.

[0034] For example, the vehicle may be any one of an EV (Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plugin Hybrid Electric Vehicle), and the vehicle is not limited thereto.

Description of Signs

[0035] 11 Driving force torque correction means 12 Sprung vibration control means 13 Total calculation means 14 Guard processing means

Claims

【Claim 1】 In the control of the turning behavior of a vehicle, a driving force torque correction means for calculating a correction amount of the driving force as an operation amount for controlling the yaw rate of the vehicle to a target yaw rate, which is the target value, and calculating a required corrected torque value; A sprung vibration control means for calculating a torque value for reducing the sway of the vehicle body; A total calculation means for calculating a total torque obtained by adding the torque value calculated by the driving force torque correction means and the torque value calculated by the sprung vibration control means; A guard processing means for providing a torque upper limit and a power upper limit of the total torque calculated by the total calculation means. A driving force control device.

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