Control device for a vehicle

Abstract

The present application provides a vehicle control device that eliminates a deficiency in driving force of a vehicle after resuming constant speed control after performing override control in the constant speed control mode. The vehicle control device includes a control unit that switches and executes a normal mode and a constant speed control mode, and in the constant speed control mode, performs constant speed control that controls driving force of the vehicle to target driving force calculated using integral control based on an accumulated value of a deviation between a vehicle speed and a target vehicle speed, and in performing the constant speed control, interrupts the constant speed control when a requested driving force corresponding to an accelerator opening degree of the vehicle exceeds the target driving force in the constant speed control, and performs override control that controls the driving force of the vehicle to the requested driving force, and at a constant speed control resumption when the constant speed control is ended and the constant speed control is resumed, sets a component of the integral control in the target driving force based on the requested driving force in performing the override control when the vehicle wheels fail to climb a step.

Description

Technical Field

[0001] This invention relates to a vehicle control device. Background Technology

[0002] There are vehicles designed to assist the driver's driving operations, capable of executing a cruise control mode (e.g., cruise control mode) in addition to the normal mode that controls the vehicle's driving force based on the driver's acceleration and deceleration operations (i.e., throttle operation and brake operation). In the cruise control mode, for example, as disclosed in Patent Document 1, the vehicle's driving force is controlled independently of the driver's acceleration and deceleration operations in a way that maintains the vehicle's speed at a target speed.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-221935 Summary of the Invention

[0006] Technical issues

[0007] The following situation exists: In cruise control mode, when the driver operates the accelerator, cruise control is interrupted, and override control is executed, adjusting the vehicle's driving force to the requested driving force corresponding to the accelerator opening. However, during the execution of cruise control mode, when the vehicle attempts to cross a step on the road, sometimes the wheels become pressed against the step, and the wheels fail to climb the step. In this case, the driver accelerates to allow the vehicle to cross the step, resulting in override control being executed. Then, if the accelerator is released directly while the wheels are failing to climb the step, override control ends, and cruise control restarts.

[0008] Here, the target driving force in cruise control is sometimes controlled by feedback control such as PID control. In this case, the target driving force in cruise control may include an integral control component based on the cumulative value of the deviation between the vehicle speed and the target speed. Conventionally, the integral control component in the target driving force usually becomes zero when cruise control restarts (i.e., becomes 0). Thus, if the override control ends when the wheels fail to climb the step and cruise control restarts, the vehicle's driving force is insufficient, which could cause the vehicle to roll backwards on an uphill road, for example.

[0009] Therefore, the object of the present invention is to provide a vehicle control device that can eliminate the lack of driving force of the vehicle after the cruise control has restarted after override control has been performed in cruise control mode.

[0010] Technical solution

[0011] To address the aforementioned problems, a vehicle control device according to one embodiment of the present invention includes a control unit capable of switching between and executing a normal mode and a cruise control mode. The normal mode is a mode that controls the vehicle's driving force based on the driver's acceleration and deceleration operations, while the cruise control mode is a mode that controls the vehicle's driving force to maintain the vehicle's speed at a target speed. In the cruise control mode, the control unit performs cruise control that calculates the target driving force using integral control based on the cumulative value of the deviation between the vehicle speed and the target speed, and controls the vehicle's driving force to the target driving force. During the execution of cruise control, if the requested driving force corresponding to the vehicle's throttle opening exceeds the target driving force in the cruise control, the cruise control is interrupted, and override control is performed to control the vehicle's driving force to the requested driving force. When the cruise control restarts after the override control has ended, if the vehicle's wheels fail to climb a step, the integral control component in the target driving force is set based on the requested driving force during the execution of the override control.

[0012] In cruise control mode, if the vehicle's wheels fail to climb the step when cruise control restarts, the control unit can set the integral control component of the target driving force to a value equivalent to the requested driving force at the end of override control.

[0013] In constant speed control mode, if the vehicle's wheels fail to climb the step when constant speed control restarts, the control unit can set the integral control component of the target driving force to a value equivalent to the maximum value of the requested driving force during the execution of override control.

[0014] In cruise control mode, if the vehicle's wheels fail to climb the step when cruise control restarts, the control unit can, in addition to requesting driving force during the execution of override control, also set the integral control component of the target driving force based on the gradient of the road on which the vehicle is traveling.

[0015] As a cruise control mode, the control unit can switch and execute a high-speed cruise control mode and a low-speed cruise control mode where the target vehicle speed is set to a value lower than the target vehicle speed in the high-speed cruise control mode. In the low-speed cruise control mode, if the vehicle wheels fail to climb the step when cruise control restarts, the integral control component in the target driving force is set based on the requested driving force during the execution of the override control.

[0016] Technical effect

[0017] According to the present invention, the insufficient driving force of the vehicle after the cruise control restarts following the execution of override control in cruise control mode can be eliminated. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing a simplified configuration of a vehicle equipped with a control device according to an embodiment of the present invention.

[0019] Figure 2 This is a block diagram illustrating an example of the functional configuration of a control device according to an embodiment of the present invention.

[0020] Figure 3 This is a flowchart illustrating an example of the process related to drive force control performed by the control unit during the execution of the constant speed control mode in an embodiment of the present invention.

[0021] Figure 4 This is a diagram illustrating an example of the transition of various state variables during the execution of the constant speed control mode of the comparative example.

[0022] Figure 5 This is a diagram illustrating an example of the transition of various state quantities during the execution of the constant speed control mode according to an embodiment of the present invention.

[0023] Figure 6 This illustrates the progression of various state variables during the execution of the constant speed control mode according to an embodiment of the present invention. Figure 5 The examples are different from the diagrams.

[0024] Figure 7 This illustrates the progression of various state variables during the execution of the constant speed control mode according to an embodiment of the present invention. Figure 5 and Figure 6 The examples are different from the diagrams.

[0025] Symbol Explanation

[0026] 1 vehicle

[0027] 11a, 11b Front wheels (wheels)

[0028] 11c, 11d Rear wheels (wheels)

[0029] 13f Front differential

[0030] 13r rear differential

[0031] 15f Front-wheel drive motor

[0032] 15r rear-wheel drive motor

[0033] 17f converter

[0034] 17r converter

[0035] 19 batteries

[0036] 100 Control device

[0037] 110 Determination Department

[0038] 120 Control Department

[0039] 121 Judgment Department

[0040] 122 Motor Control Unit

[0041] 201 Throttle Opening Sensor

[0042] 203 Brake Sensor

[0043] 205F Front Wheel Motor Speed ​​Sensor

[0044] 205r Rear Wheel Motor Speed ​​Sensor Detailed Implementation

[0045] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and are not intended to limit the scope of the invention unless specifically indicated. It should be noted that in this specification and the accompanying drawings, elements having substantially the same function or structure are labeled with the same symbols, and repeated descriptions are omitted. Furthermore, elements not directly related to the present invention are omitted from the illustrations.

[0046] <Vehicle Composition>

[0047] Reference Figure 1 and Figure 2 The configuration of a vehicle 1 equipped with the control device 100 according to an embodiment of the present invention will be described.

[0048] Figure 1 This is a schematic diagram showing the simplified configuration of vehicle 1. Figure 1 The image shows vehicle 1. The forward direction of vehicle 1 is set as forward, and the reverse direction on the opposite side is set as backward. The left and right sides in the forward-facing state are set as left and right, respectively.

[0049] Vehicle 1 is equipped with a drive motor (specifically, Figure 1 An electric vehicle that uses a front-wheel drive motor 15f and a rear-wheel drive motor 15r as its drive sources and moves using the power output from the drive motors.

[0050] It should be noted that the vehicle 1 described below is merely one example of a vehicle equipped with the control device of the present invention. As will be said later, the configuration of a vehicle equipped with the control device of the present invention is not particularly limited to the configuration of vehicle 1.

[0051] like Figure 1As shown, vehicle 1 includes front wheels 11a and 11b, rear wheels 11c and 11d, a front differential 13f, a rear differential 13r, a front-wheel drive motor 15f, a rear-wheel drive motor 15r, a converter 17f, a converter 17r, a battery 19, a control device 100, a throttle opening sensor 201, a brake sensor 203, a front wheel motor speed sensor 205f, and a rear wheel motor speed sensor 205r.

[0052] Hereinafter, without distinguishing between the front wheels 11a, 11b, 11c, and 11d, they will also be referred to as wheels 11. Similarly, without distinguishing between the front-wheel drive motor 15f and the rear-wheel drive motor 15r, they will also be referred to as drive motor 15. Furthermore, without distinguishing between converter 17f and converter 17r, they will also be referred to as converter 17. Finally, without distinguishing between the front-wheel motor speed sensor 205f and the rear-wheel motor speed sensor 205r, they will also be referred to as motor speed sensor 205.

[0053] The front-wheel drive motor 15f is a drive motor that outputs power to drive the front wheels 11a and 11b. It should be noted that front wheel 11a is equivalent to the left front wheel, and front wheel 11b is equivalent to the right front wheel.

[0054] Specifically, the front-wheel drive motor 15f is driven by electricity supplied from the battery 19. The front-wheel drive motor 15f is connected to the front differential 13f. The front differential 13f is connected to the front wheels 11a and 11b via drive shafts. The power output from the front-wheel drive motor 15f is transmitted to the front differential 13f and then distributed and transmitted to the front wheels 11a and 11b through the front differential 13f.

[0055] The front-wheel drive motor 15f is, for example, a multiphase AC motor, and is connected to the battery 19 via a converter 17f. The DC power supplied from the battery 19 is converted into AC power by the converter 17f and supplied to the front-wheel drive motor 15f.

[0056] In addition to providing power to drive the front wheels 11a and 11b, the front-wheel drive motor 15f also functions as a generator, utilizing the kinetic energy of the front wheels 11a and 11b to generate electricity. When the front-wheel drive motor 15f functions as a generator, it generates electricity and applies regenerative braking force to the vehicle 1. The alternating current (AC) power generated by the front-wheel drive motor 15f is converted to direct current (DC) power by the converter 17f and supplied to the battery 19. As a result, the battery 19 is charged.

[0057] The rear-wheel drive motor 15r is a drive motor that outputs power to drive the rear wheels 11c and 11d. It should be noted that rear wheel 11c is equivalent to the left rear wheel, and rear wheel 11d is equivalent to the right rear wheel.

[0058] Specifically, the rear-wheel drive motor 15r is driven by electricity supplied from the battery 19. The rear-wheel drive motor 15r is connected to the rear differential 13r. The rear differential 13r is connected to the rear wheels 11c and 11d via drive shafts. The power output from the rear-wheel drive motor 15r is transmitted to the rear differential 13r and then distributed and transmitted to the rear wheels 11c and 11d through the rear differential 13r.

[0059] The rear-wheel drive motor 15r is, for example, a multiphase AC motor, and is connected to the battery 19 via a converter 17r. The DC power supplied from the battery 19 is converted into AC power by the converter 17r and supplied to the rear-wheel drive motor 15r.

[0060] In addition to providing power to drive the rear wheels 11c and 11d, the rear-wheel drive motor 15r also functions as a generator, utilizing the kinetic energy of the rear wheels 11c and 11d to generate electricity. When the rear-wheel drive motor 15r functions as a generator, it generates electricity and applies regenerative braking force to the vehicle 1. The alternating current (AC) power generated by the rear-wheel drive motor 15r is converted to direct current (DC) power by the converter 17r and supplied to the battery 19. As a result, the battery 19 is charged.

[0061] Throttle opening sensor 201 detects the throttle opening as a measure of the driver's operation on the accelerator pedal and outputs the detection result.

[0062] Brake sensor 203 detects the brake operation amount as the amount of the driver's operation on the brake pedal and outputs the detection result.

[0063] The front wheel motor speed sensor 205f detects the speed of the front wheel drive motor 15f and outputs the detection result. The rear wheel motor speed sensor 205r detects the speed of the rear wheel drive motor 15r and outputs the detection result. The detection results of the motor speed sensors 205 are used as information indicating the speed of the power transmission shaft of the vehicle 1 (specifically, the shaft included in the power transmission system between the drive motor 15 and the wheels 11) in the processing performed by the control device 100.

[0064] The control device 100 includes a CPU (Central Processing Unit) as an arithmetic processing device, a ROM (Read Only Memory) as a storage element that stores programs and / or arithmetic parameters used by the CPU, and a RAM (Random Access Memory) as a storage element that temporarily stores parameters that change appropriately during CPU execution.

[0065] The control unit 100 communicates with various devices mounted on the vehicle 1 (e.g., the transducer 17, the throttle opening sensor 201, the brake sensor 203, and the motor speed sensor 205). The communication between the control unit 100 and the various devices is achieved, for example, using CAN (Controller Area Network) communication.

[0066] Figure 2 This is a block diagram illustrating an example of the functional configuration of the control device 100.

[0067] For example, such as Figure 2 As shown, the control device 100 includes a determining unit 110 and a control unit 120.

[0068] The determination unit 110 determines the vehicle speed (hereinafter also simply referred to as vehicle speed) based on the number of revolutions of the power transmission shaft of the vehicle 1. The information indicating the vehicle speed determined by the determination unit 110 is output to the control unit 120 and used for processing performed by the control unit 120.

[0069] Specifically, the determining unit 110 determines the vehicle speed based on the detection results of the motor speed sensor 205. It should be noted that in determining the vehicle speed, the detection results of both the front wheel motor speed sensor 205f and the rear wheel motor speed sensor 205r can be used, or only the detection result of one of the front wheel motor speed sensor 205f and the rear wheel motor speed sensor 205r can be used. Furthermore, in determining the vehicle speed, information other than the detection results of the motor speed sensor 205 (for example, information indicating the rotational speed of the drive shaft connecting the wheels 11 and the differential) can also be used as information indicating the rotational speed of the power transmission shaft of the vehicle 1.

[0070] The control unit 120 controls the movement of the vehicle 1 by controlling the operation of various devices within the vehicle 1. For example, the control unit 120 includes a decision unit 121 and a motor control unit 122.

[0071] The determination unit 121 uses information sent from various devices within the vehicle 1 to the control unit 100 to make various determinations. The determination results of the determination unit 121 are used for various processes performed by the control unit 120.

[0072] The motor control unit 122 controls the operation of each drive motor 15 by controlling the operation of each converter 17. Specifically, the motor control unit 122 controls the power supply between the battery 19 and the front-wheel drive motor 15f by controlling the operation of the switching element of the converter 17f. Thus, the motor control unit 122 can control the generation of power and electricity from the front-wheel drive motor 15f. Furthermore, the motor control unit 122 controls the power supply between the battery 19 and the rear-wheel drive motor 15r by controlling the operation of the switching element of the converter 17r. Thus, the motor control unit 122 can control the generation of power and electricity from the rear-wheel drive motor 15r.

[0073] It should be noted that when the motor control unit 122 drives the drive motors 15 to apply driving force to the vehicle 1, it can drive both the front-wheel drive motor 15f and the rear-wheel drive motor 15r, or it can drive only one of the front-wheel drive motor 15f and the rear-wheel drive motor 15r. The distribution of driving force among the drive motors 15 when both the front-wheel drive motor 15f and the rear-wheel drive motor 15r are driven can be appropriately set. The motor control unit 122 can control the driving force of the vehicle 1 (i.e., the driving force applied to the vehicle 1) by controlling the driving force of each drive motor 15.

[0074] Here, as the driving mode of vehicle 1, the control unit 120 can switch between and execute a normal mode and a cruise control mode. The normal mode is a driving mode that controls the driving force of vehicle 1 based on the driver's acceleration and deceleration operations (i.e., throttle operation and brake operation). The cruise control mode is a driving mode that controls the driving force of vehicle 1 to maintain the vehicle speed at a target speed without relying on the driver's acceleration and deceleration operations. It should be noted that the cruise control mode is sometimes referred to as cruise control mode.

[0075] Furthermore, as a cruise control mode, the control unit 120 can switch between and execute a high-speed cruise control mode and a low-speed cruise control mode. It should be noted that the high-speed cruise control mode is sometimes referred to as the high-speed cruise control mode, and the low-speed cruise control mode is sometimes referred to as the low-speed cruise control mode. In the low-speed cruise control mode, the target vehicle speed is set to a value lower than the target vehicle speed in the high-speed cruise control mode. For example, the target vehicle speed in the high-speed cruise control mode is set to a speed within the range of 20 km / h to 115 km / h, and the target vehicle speed in the low-speed cruise control mode is set to a speed within the range of 2 km / h to 15 km / h. The target vehicle speed in the cruise control mode can be adjusted, for example, through driver input.

[0076] For example, vehicle 1 is equipped with an input device (e.g., a switch or button) that the driver can operate to select a driving mode. This input device is used to select which driving mode to execute: normal mode, high-speed cruise control mode, or low-speed cruise control mode. Control unit 120 executes the driving mode selected by the driver. It should be noted that if the driver performs a specific operation such as braking during the execution of cruise control mode, control unit 120 stops cruise control mode and switches to normal mode.

[0077] In normal operation, the control unit 120 controls the operation of the drive motor 15 such that the driving force of the vehicle 1 corresponds to the throttle opening. Therefore, the driving force of the vehicle 1 can be controlled according to the driver's throttle operation. Furthermore, the control unit 120 controls the operation of braking devices such as hydraulic brakes mounted on the vehicle 1 such that the braking force applied to the vehicle 1 corresponds to the amount of brake operation. Therefore, the braking force applied to the vehicle 1 can be controlled according to the driver's brake operation.

[0078] In constant speed control mode, the control unit 120 calculates the target driving force in a manner that brings the vehicle speed close to the target vehicle speed, and controls the driving force of the vehicle 1 to the target driving force. For example, the control unit 120 calculates the target driving force using feedforward control based on vehicle speed and feedback control based on the deviation between the vehicle speed and the target vehicle speed (e.g., PID control). In this case, the calculated target driving force Fc is expressed, for example, by the following equation (1).

[0079] Fc=Ff+Fp+Fi+Fd···(1)

[0080] In equation (1), Ff represents the component of feedforward control based on vehicle speed, Fp represents the component of proportional control based on the deviation between vehicle speed and target vehicle speed (i.e., the P component), Fi represents the component of integral control based on the cumulative value of the above deviation (i.e., the I component), and Fd represents the component of differential control based on the derivative value of the above deviation (i.e., the D component). Specifically, the driving force Fp of the P component is obtained by multiplying the above deviation by a gain. Specifically, the driving force Fi of the I component is obtained by multiplying the cumulative value of the above deviation by a gain. Specifically, the driving force Fd of the D component is obtained by multiplying the derivative value of the above deviation by a gain. The driving force Ff of the feedforward control component is equivalent to the driving force expected to be required to maintain the vehicle speed at the target vehicle speed when the vehicle 1 is traveling on a flat road. Furthermore, a flat road refers to a road where the absolute value of the gradient (i.e., the inclination of the vehicle 1 in the direction of travel relative to the horizontal direction) is below a predetermined value.

[0081] It should be noted that the method for calculating the target driving force Fc of the drive motor 15 is not limited to the example calculated using Equation (1). For example, the feedforward control can be omitted from the above example (i.e., the driving force Ff can also be omitted from Equation (1)), and the PID control can be replaced with PI control (i.e., the driving force Fd can also be omitted from Equation (1)).

[0082] It should be noted that the functions of the control device 100 in this embodiment can be partially shared by multiple control devices, or multiple functions can be implemented by a single control device. When the functions of the control device 100 are partially shared by multiple control devices, these multiple control devices can be connected to each other via a communication bus such as CAN.

[0083] As described above, the control unit 120 of the control device 100 can execute a cruise control mode, which controls the driving force of the vehicle 1 to maintain the vehicle speed at a target speed without relying on the driver's acceleration or deceleration operations. Here, during the execution of the cruise control mode, the control unit 120 can interrupt cruise control when the driver operates the accelerator and execute override control to control the driving force of the vehicle 1 to the requested driving force corresponding to the accelerator opening. In this embodiment, by addressing the driving force control when cruise control restarts after override control has ended, the insufficient driving force of the vehicle 1 after the restart of cruise control following the execution of override control in the cruise control mode can be eliminated. It should be noted that the details of the driving force control-related processing performed by the control unit 120 during the execution of the cruise control mode will be explained later.

[0084] <Action of the control device>

[0085] Next, refer to Figures 3-7 The operation of the control device 100 according to an embodiment of the present invention will be described.

[0086] Figure 3 This is a flowchart illustrating an example of the process related to drive force control performed by the control unit 120 during the execution of the constant speed control mode. Figure 3 The control flow shown begins when constant speed control is being performed in constant speed control mode, and repeats after the constant speed control is completed.

[0087] As will be described below, according to Figure 3The control flow shown, when the overdrive control ends after the failure of wheel 11 to climb the step and the cruise control restarts, can suppress the insufficient driving force of vehicle 1. Here, the lower the target speed of the cruise control mode, the easier it is for the actual vehicle speed to become insufficient relative to the speed required for wheel 11 to climb the step, and the easier it is for wheel 11 to fail to climb the step. Therefore, compared to the high-speed cruise control mode, wheel 11 is more likely to fail to climb the step in the low-speed cruise control mode. Therefore, the control unit 120 particularly preferably performs the following during the execution of the low-speed cruise control mode: Figure 3 The control process. The control unit 120 can also execute the following during the execution of the high-speed constant speed control mode: Figure 3 The control process.

[0088] like Figure 3 When the control flow shown begins, firstly, in step S101, the determination unit 121 determines whether the start condition for override control has been met. The start condition for override control is that the requested driving force corresponding to the throttle opening of vehicle 1 exceeds the target driving force in cruise control. The requested driving force is the driving force requested by the driver through throttle operation. That is, if the start condition is met, the driver wishes to interrupt cruise control and increase the driving force of vehicle 1.

[0089] If the determination in step S101 is negative (i.e., if the start condition for override control is not met), Figure 3 The control flow shown ends. On the other hand, if the determination in step S101 is yes (i.e., if the start condition for override control is met), the process proceeds to step S102, and the motor control unit 122 interrupts constant speed control. Then, in the next step after step S102, in step S103, the motor control unit 122 begins override control. In override control, the motor control unit 122 controls the driving force of the vehicle 1 to the requested driving force corresponding to the throttle opening.

[0090] In the next step after step S103, in step S104, the determination unit 121 determines whether the end condition of the override control has been met. The end condition of the override control is, for example, the driver's throttle operation being released. For example, the determination unit 121 can determine that the throttle operation has been released if the requested driving force is less than the target driving force at the time when the cruise control is interrupted.

[0091] If the determination in step S104 is negative (i.e., if the termination condition for override control is not met), the determination process in step S104 is repeated. On the other hand, if the determination in step S104 is positive (i.e., if the termination condition for override control is met), the process proceeds to step S105, and the motor control unit 122 ends the override control.

[0092] In the next step after S105, in step S106, the determination unit 121 determines whether the wheel 11 has failed to climb the step. The failure of the wheel 11 to climb the step occurs when the vehicle 1 attempts to cross or pass over the step, and the wheel 11 is in a state of contact with the step. Here, a step can be a strip-shaped protrusion on the road surface (e.g., a speed bump) or a joint between road surfaces with varying elevations (e.g., the joint between a lane and a sidewalk). Regardless of the type of step, there are instances where the wheel 11 is in a state of contact with the step and fails to climb it.

[0093] In step S106, the determination unit 121 determines, for example, whether the wheel 11 failed to climb the step based on the driving state of the drive motor 15 and the vehicle speed of the vehicle 1. For example, if the vehicle speed is maintained below a threshold (e.g., a value near 0 km / h) for more than a reference time, even though the drive motor 15 is driven and driving force is generated in the vehicle 1, the determination unit 121 determines that the wheel 11 failed to climb the step. The reference time is set to an appropriate time that can be determined as a time when it is impossible to eliminate the state of the vehicle speed being maintained below the threshold, even though driving force is generated in the vehicle 1.

[0094] If the determination in step S106 is yes (i.e., if the wheel 11 fails to climb the step), in step S107, the motor control unit 122 sets the I component (i.e., the integral control component) of the target driving force of the constant speed control based on the requested driving force during the execution of the override control. Specifically, the motor control unit 122 sets the cumulative value of the deviation in the integral control in a way that makes the I component of the target driving force a value corresponding to the requested driving force during the execution of the override control.

[0095] By setting the target driving force I component as described above, when cruise control restarts after the override control has ended due to wheel 11 failing to climb the step, the target driving force I component, without being zeroed (i.e., not becoming 0), becomes a value corresponding to the requested driving force during the execution of override control. Therefore, since the insufficient driving force of vehicle 1 after the restart of cruise control can be eliminated, situations such as vehicle 1 sliding down an uphill road can be suppressed. It should be noted that, referring to... Figures 5-7 The details of setting the cumulative value of the request driving force during the execution process based on override control will be explained later.

[0096] If the determination in step S106 is negative (i.e., if it is not determined that wheel 11 failed to climb the step), the process proceeds to step S108, where the motor control unit 122 sets the I-component in the target driving force of the constant speed control to zero (i.e., sets it to 0). Specifically, the motor control unit 122 sets the I-component to zero by setting the accumulated value of the deviation in the integral control to zero. When constant speed control restarts after the override control ended without the state of wheel 11 failing to climb the step (e.g., the state of successfully climbing the step), it is preferable to set the I-component to zero in this way from the viewpoint of suppressing the rapid acceleration of vehicle 1. For example, there is a situation where, although vehicle 1 is traveling uphill during the execution of override control, vehicle 1 enters a flat road at the end of the override control. In such a case, if the I-component is not set to zero, vehicle 1 may accelerate rapidly.

[0097] The next step after step S107 or S108 proceeds to step S109, where the motor control unit 122 resumes constant speed control. Figure 3 The control flow shown has ended.

[0098] Here, refer to Figure 4 and Figure 5 The differences between the constant speed control mode of the comparative example and the constant speed control mode of this embodiment will be explained.

[0099] Figure 4 This is a diagram illustrating an example of the transitions of various state variables during the execution of the constant-speed control mode in a comparative example. Figure 4 In the diagram, the vehicle speed [km / h], the step-climbing failure flag, the throttle opening [%], the override control flag, the actual driving force [N], the target driving force [N] for cruise control, and the requested driving force [N] are shown as various state quantities. The actual driving force [N] refers to the driving force actually applied to vehicle 1. It should be noted that the diagram of the D component in the target driving force for cruise control is omitted.

[0100] If the wheel 11 fails to climb the step, the step-climbing failure flag becomes 1; if the wheel 11 does not fail to climb the step, the step-climbing failure flag becomes 0. When override control is executed, the override control flag becomes 1; when override control is not executed, the override control flag becomes 0. These flags are stored, for example, in the storage element of the control device 100 and are rewritten by the control unit 120.

[0101] exist Figure 4In the example shown, before time point T1, vehicle 1 is traveling uphill in cruise control mode. Then, at time point T1, wheel 11 comes into contact with the step, failing to climb it. The vehicle speed begins to decrease from time point T1 and reaches 0 km / h at time point T2. Thus, as wheel 11 fails to climb the step, at time point T3, after time point T2, the step-climbing failure flag changes from 0 to 1.

[0102] After time T2, when the vehicle speed reaches 0 km / h, the P component of the target driving force for cruise control increases, and the actual driving force also increases. However, after time T2, the state of wheel 11 failing to climb the step remains unchanged. Here, at time T4, after time T3, the driver operates the accelerator. Therefore, at time T4, the accelerator opening increases, and the requested driving force also increases. Then, the situation where the requested driving force exceeds the target driving force is used as a trigger point, interrupting cruise control and executing overdrive control. Therefore, at time T4, the overdrive control flag switches from 0 to 1. After time T4, the actual driving force is controlled to be the requested driving force.

[0103] At time point T5, following time point T4, the driver's throttle operation is released. Therefore, at time point T5, the throttle opening decreases to 0, and the requested driving force also decreases to 0. Then, using the release of the driver's throttle operation as a trigger point, overdrive control ends and cruise control restarts. Therefore, at time point T5, the overdrive control flag switches from 1 to 0.

[0104] In the comparative example, at time T5, when cruise control restarts as a re-start of cruise control after the end of overdrive control, the I-component of the target driving force of cruise control is zero, regardless of whether wheel 11 fails to climb the step. Then, after time T5, the I-component of the target driving force rises from zero. Here, since the I-component is calculated based on the cumulative value of the deviation between the vehicle speed and the target vehicle speed, it changes slowly. Therefore, after time T5, the target driving force of cruise control rises slowly from zero. Consequently, after time T5, the actual driving force is insufficient, and vehicle 1 slides down. Figure 4 In the example, after time point T5, the vehicle speed takes a negative value, and vehicle 1 reverses.

[0105] Figure 5 This is a diagram illustrating an example of the transition of various state variables during the execution of the constant speed control mode of this embodiment. Figure 5 The state variables shown are respectively with Figure 4 same.

[0106] As described above, in this embodiment, when the wheel 11 fails to climb the step during the restart of constant speed control after the override control has ended, the control unit 120 sets the I component (i.e., the integral control component) of the target driving force of constant speed control based on the requested driving force during the execution of the override control. Figure 5 In the example, at time T5, when the constant speed control restarts, it is determined that wheel 11 failed to climb the step, therefore... Figure 4 Unlike other examples, the I component of the target driving force in constant speed control, without being zeroed (i.e., not becoming 0), becomes the value corresponding to the requested driving force between time point T4 and time point T5 in the execution process of overdrive control.

[0107] exist Figure 5 In the example, the request driving force becomes approximately constant between time point T4 and time point T5. Figure 5 In the target driving force curve, the requested driving force between time point T4 and time point T5 is represented by a double-dotted line L1. For example, at time point T5 when constant speed control restarts, the control unit 120 sets the I component of the target driving force for constant speed control in a manner consistent with the requested driving force between time points T4 and T5. Alternatively, at time point T5, the control unit 120 may set the I component of the target driving force to a value obtained by adding or subtracting a predetermined adjustment value from the requested driving force between time points T4 and T5.

[0108] As mentioned above, in Figure 5 In the example, at time T5 when cruise control restarts after the failure of wheel 11 to climb the step, the I component of the target driving force of cruise control becomes the requested driving force between time T4 and time T5. Therefore, after time T5, the target driving force of cruise control increases from the requested driving force between time T4 and time T5. Thus, after time T5, the insufficiency of actual driving force is eliminated, and the downward movement of vehicle 1 is suppressed. Figure 5 In the example, after time point T5, the vehicle speed is maintained at 0 km / h, and vehicle 1 does not roll backward.

[0109] In the above-mentioned Figure 5 In the example, the requested driving force remains approximately constant during the execution of override control. However, the requested driving force may change during the execution of override control. See below for reference. Figure 6 and Figure 7 An example is given of requesting a change in driving force during the execution of overdrive control.

[0110] Figure 6This illustrates the progression of various state variables during the execution of the constant speed control mode in this embodiment. Figure 5 The examples are different from the diagrams. Figure 6 The state variables shown are respectively with Figure 4 and Figure 5 same.

[0111] exist Figure 6 In the example, between time point T4 and time point T5 during the execution process as override control, and Figure 5 The examples differ, and the request driver changes. Specifically, the request driver increases from time point T4 to time point T6, reaches its maximum at time point T6, and then decreases from time point T6 to time point T5. Figure 6 In the target driving force curve, the double-dotted line L2 is used to represent the request driving force between time point T4 and time point T5.

[0112] exist Figure 6 In the example, at time point T5 when cruise control restarts, the control unit 120 sets the I component of the target driving force of cruise control to a value equivalent to the requested driving force at time point T5 when overdrive control ends. For example, at time point T5, the control unit 120 sets the I component of the target driving force of cruise control in a manner consistent with the requested driving force at time point T5 when overdrive control ends. Therefore, after cruise control restarts, discomfort to the driver caused by a large change in the driving force applied to vehicle 1 is suppressed. Alternatively, at time point T5, the control unit 120 may set the I component of the target driving force to a value obtained by adding or subtracting a predetermined adjustment value from the requested driving force at time point T5 when overdrive control ends.

[0113] Figure 7 This illustrates the progression of various state variables during the execution of the constant speed control mode in this embodiment. Figure 5 and Figure 6 The examples are different from the diagrams. Figure 7 The state variables shown are respectively with Figures 4-6 Same. Figure 7 In the example, between time point T4 and time point T5 during the execution process as overdrive control, the requested driving force and Figure 6 The examples also vary.

[0114] exist Figure 7In the example, at time T5 when cruise control restarts, the control unit 120 sets the I-component of the target driving force for cruise control to a value equivalent to the maximum value of the requested driving force between time points T4 and T5 during the execution of overdrive control (i.e., the requested driving force at time point T6). For example, the control unit 120 sets the I-component of the target driving force for cruise control at time point T5 in a manner consistent with the requested driving force at time point T6. This more effectively eliminates the insufficient driving force of vehicle 1 after the restart of cruise control. Therefore, for example, it is possible to more reliably suppress the sliding of vehicle 1 on an uphill road, thereby enabling earlier crossing of steps. Alternatively, at time point T5, the control unit 120 may also set the I-component of the target driving force to a value obtained by adding or subtracting a predetermined adjustment value from the requested driving force at time point T6.

[0115] Here, in the cruise control mode, when cruise control restarts and wheel 11 fails to climb the step, in addition to the requested driving force during the execution of override control, the control unit 120 can also set the I component of the target driving force based on other parameters. For example, the gradient of the road on which vehicle 1 travels is listed as one of these other parameters. It should be noted that the gradient of the road can be obtained using, for example, the detection results of a sensor that detects the acceleration of vehicle 1, or map data.

[0116] When the road surface is vertically upward relative to the direction of travel (i.e., when the road surface is uphill), after the cruise control restarts, it is highly necessary to increase the I component of the target driving force in order to more reliably suppress the vehicle 1 from rolling backward and thus achieve the step crossing earlier. On the other hand, when the road surface is vertically downward relative to the direction of travel (i.e., when the road surface is downhill), after the cruise control restarts, it is highly necessary to make the I component of the target driving force close to the requested driving force at the end of the overdrive control in order to suppress the discomfort caused to the driver due to the large change in the driving force applied to the vehicle 1.

[0117] Therefore, for example, when cruise control restarts, if wheel 11 fails to climb the step and the road is uphill, control unit 120 may set the I component of the target driving force to a value equivalent to the maximum value of the requested driving force during the execution of override control. On the other hand, when cruise control restarts, if wheel 11 fails to climb the step and the road is downhill, control unit 120 may also set the I component of the target driving force to a value equivalent to the requested driving force at the end of override control.

[0118] It should be noted that the control unit 120 can also change the set value of the I component in the target driving force according to the slope of the road when the driving road is uphill. Similarly, the control unit 120 can also change the set value of the I component in the target driving force according to the slope of the road when the driving road is downhill.

[0119] <Effects of the control device>

[0120] Next, the effects of the control device 100 according to the embodiment of the present invention will be explained.

[0121] In the control device 100 of this embodiment, when the control unit 120 restarts constant speed control after the override control has ended, and the wheel 11 fails to climb the step, it sets the I component (i.e., the integral control component) of the target driving force of the constant speed control based on the requested driving force during the execution of the override control. Therefore, when the constant speed control restarts after the override control ends in the state where the wheel 11 failed to climb the step, the I component of the target driving force, without being zeroed (i.e., not becoming 0), becomes a value corresponding to the requested driving force during the execution of the override control. Thus, the insufficient driving force of the vehicle 1 after the restart of constant speed control is eliminated. This suppresses, for example, the vehicle 1 sliding down an uphill road. Furthermore, for example, even on a downhill road, it is possible to eliminate the situation where the driving force of the vehicle 1 is significantly insufficient relative to the driving force required to climb the step.

[0122] Furthermore, in the control device 100 of this embodiment, it is preferable that, in the cruise control mode, when cruise control restarts and the wheel 11 fails to climb the step, the control unit 120 sets the I component of the target driving force to a value equivalent to the requested driving force at the end of the override control. Therefore, after cruise control restarts, it is possible to suppress discomfort to the driver caused by large changes in the driving force applied to the vehicle 1.

[0123] Furthermore, in the control device 100 of this embodiment, it is preferable that, in the constant speed control mode, when constant speed control restarts and the wheel 11 fails to climb the step, the control unit 120 sets the I component of the target driving force to a value equivalent to the maximum value of the requested driving force during the execution of the override control. This more effectively eliminates the insufficient driving force of the vehicle 1 after constant speed control restarts. Therefore, for example, it is possible to more reliably suppress the vehicle 1 from sliding down an uphill road, thereby enabling the step to be climbed earlier.

[0124] Furthermore, in the control device 100 of this embodiment, it is preferable that, in the constant speed control mode, when constant speed control restarts and the wheel 11 fails to climb the step, the control unit 120 sets the I component of the target driving force based on the slope of the road on which the vehicle 1 travels, in addition to the requested driving force during the execution of override control. Therefore, when constant speed control restarts after the override control has ended due to the wheel 11 failing to climb the step, the I component of the target driving force can be set more appropriately based on the slope of the road.

[0125] Furthermore, in the control device 100 of this embodiment, it is preferable that the control unit 120, in the low-speed constant speed control mode, sets the I component of the target driving force based on the requested driving force during the execution of the override control when the constant speed control restarts and the wheel 11 fails to climb the step. As described above, compared to the high-speed constant speed control mode, the wheel 11 is more likely to fail to climb the step in the low-speed constant speed control mode. Therefore, it is possible to effectively and flexibly utilize the effect of eliminating the insufficient driving force of the vehicle 1 after the constant speed control restarts.

[0126] While preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is by no means limited to the embodiments described above, and various modifications or alterations within the scope of the claims are naturally also within the technical scope of the present invention.

[0127] For example, in the above description, vehicle 1, which is an electric vehicle equipped with a front-wheel drive motor 15f and a rear-wheel drive motor 15r as drive sources, was described. However, the configuration of a vehicle equipped with the control device of the present invention is not particularly limited to vehicle 1. For example, a vehicle equipped with the control device of the present invention could be an electric vehicle with drive motors provided for each wheel (i.e., having four drive motors), or a hybrid vehicle equipped with drive motors and an engine as drive sources. Furthermore, for example, a vehicle equipped with the control device of the present invention could also be a vehicle similar to the one described above. Figure 1 The vehicle described is a vehicle in which the constituent elements have been added, changed, or deleted.

[0128] Furthermore, for example, the processes described using flowcharts in this specification may not necessarily be executed in the order shown in the flowcharts. Additionally, additional processing steps may be used, or some processing steps may be omitted.

Claims

1. A vehicle control device, characterized in that, The system includes a control unit capable of switching between and executing a normal mode and a cruise control mode. The normal mode controls the vehicle's driving force based on the driver's acceleration and deceleration operations, while the cruise control mode controls the vehicle's driving force to maintain the vehicle's speed at a target speed. In the constant speed control mode, the control unit performs integral control based on the cumulative value of the deviation between the vehicle speed and the target vehicle speed to calculate the target driving force, and controls the vehicle's driving force to the target driving force for constant speed control. During the execution of the cruise control, if the requested driving force corresponding to the vehicle's throttle opening exceeds the target driving force in the cruise control, the cruise control is interrupted, and override control is executed to control the vehicle's driving force to the requested driving force. When the cruise control restarts after the override control has ended, if the vehicle's wheels fail to climb the step, the integral control component in the target driving force is set based on the requested driving force during the execution of the override control. On the other hand, if the vehicle's wheels do not fail to climb the step, the integral control component in the target driving force is set to zero.

2. The vehicle control device according to claim 1, characterized in that, In the constant speed control mode, if the vehicle's wheels fail to climb the step when constant speed control restarts, the control unit sets the integral control component of the target driving force to a value equivalent to the requested driving force at the end of the override control.

3. The vehicle control device according to claim 1, characterized in that, In the constant speed control mode, if the vehicle's wheels fail to climb the step when constant speed control restarts, the control unit sets the integral control component of the target driving force to a value equivalent to the maximum value of the requested driving force during the execution of the override control.

4. The vehicle control device according to claim 2, characterized in that, In the constant speed control mode, if the vehicle's wheels fail to climb the step when constant speed control restarts, the control unit sets the integral control component of the target driving force to a value equivalent to the maximum value of the requested driving force during the execution of the override control.

5. The vehicle control device according to any one of claims 1 to 4, characterized in that, In the constant speed control mode, if the vehicle's wheels fail to climb the step when constant speed control restarts, the control unit, in addition to the requested driving force during the execution of the override control, sets the integral control component of the target driving force based on the slope of the road on which the vehicle is traveling.

6. The vehicle control device according to any one of claims 1 to 4, characterized in that, As the cruise control mode, the control unit can switch and execute a high-speed cruise control mode and a low-speed cruise control mode in which the target vehicle speed is set to a value lower than the target vehicle speed of the high-speed cruise control mode. In the low-speed constant speed control mode, if the vehicle's wheels fail to climb the step when the constant speed control restarts, the integral control component in the target driving force is set based on the requested driving force during the execution of the override control.

7. The vehicle control device according to claim 5, characterized in that, As the cruise control mode, the control unit can switch and execute a high-speed cruise control mode and a low-speed cruise control mode in which the target vehicle speed is set to a value lower than the target vehicle speed of the high-speed cruise control mode. In the low-speed constant speed control mode, if the vehicle's wheels fail to climb the step when the constant speed control restarts, the integral control component in the target driving force is set based on the requested driving force during the execution of the override control.

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