Vehicle control device

Abstract

This invention provides a vehicle control device that avoids adverse conditions caused by overheating of the drive motor and does not increase the cost of the control structure, and can suppress rollback when parking on an incline. The vehicle control device includes: a drive motor for driving the vehicle; a drive shaft connected to the drive motor; a parking gear fixed to the drive shaft; a parking pawl engaged with the parking gear; an actuator that, through operation of a parking switch, moves the parking pawl to a locked position and a unlocked position, locking the drive shaft; a slope detection component for detecting the vehicle's slope; a rotation angle detection component for detecting the rotation angle of the drive motor; and a motor angle control component that, after the actuator operates, rotates the drive motor by a predetermined angle, this predetermined angle corresponding to the slope detected by the slope detection component.

Description

Technical Field

[0001] This invention relates to a vehicle control device for controlling the movement of a vehicle. Background Technology

[0002] In automobiles and other vehicles, there is a parking mechanism for locking the wheels when parking. When the wheels are locked using the parking mechanism on a slope, if the actuator responds slowly after the parking switch is pressed, the parking pawl will engage the parking gear slowly, which may cause the vehicle to move slightly down the slope (hereinafter, this phenomenon is referred to as "(vehicle) slippage" in this manual).

[0003] To suppress this downward movement, Patent Document 1 describes a control method that determines whether the vehicle is on a slope based on a signal from a gyroscope sensor. If the vehicle is on a slope and the brakes are on, and the vehicle speed is below a specified threshold, motor control is implemented, and the vehicle remains in standby mode until the parking switch is pressed. In this motor control, the position of the parking gear and the angle of rotation of the parking gear when the actuator moves the parking pawl from the unlocked position to the locked position are pre-calculated. Based on these position and angle, a motor torque is applied so that the parking gear is engaged with the parking pawl, causing the drive motor to rotate. Through the rotation of the drive motor in this motor control, the phases of the parking gear and the parking pawl are pre-aligned. Therefore, if the parking switch is pressed and the actuator operates, the parking gear and the parking pawl engage, suppressing the vehicle's downward movement.

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2009-30637 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] However, in the aforementioned control, such as Figure 7 As shown, the system remains in a standby state where torque is applied via motor control until the parking switch (P switch) is pressed. Therefore, if the time t until the parking switch is pressed is long, there is a concern that the motor temperature may become too high, preventing the application of torque. Furthermore, there is a possibility that the correspondence between the rotation angle of the drive motor and the rotation position of the parking gear may deviate. Learning the rotation position of the parking gear when the vehicle power is on and correcting the correspondence between the drive motor's rotation angle and the parking gear's rotation position could potentially increase the cost of the control structure.

[0009] In view of the aforementioned problems, the object of the present invention is to provide a vehicle control device that does not cause adverse conditions due to overheating of the drive motor, nor does it increase the cost of the control structure, and can suppress the vehicle from sliding downhill when parking on a slope.

[0010] [Technical means to solve the problem]

[0011] To solve the aforementioned problem, the vehicle control device 1 of the present invention includes: a drive motor 8 for driving a vehicle; a drive shaft 22 connected to the drive motor 8; a parking gear 24 fixed to the drive shaft 22; a parking pawl 40 engaged with the parking gear 24; an actuator 44 that, through operation of a parking locking operating member 58, moves the parking pawl 40 to a locked position and a locked-out position where it engages with the parking gear 24 and locks the drive shaft 22; a slope detection member 56 for detecting the slope of the vehicle 2; a rotation angle detection member 60 for detecting the rotation angle of the drive motor 8; and a motor angle control member 48 that, after the actuator 44 is activated, rotates the drive motor 8 by a predetermined angle, which corresponds to the slope detected by the slope detection member 56.

[0012] According to the vehicle control device of the present invention, regardless of whether there is a phase deviation between the parking gear and the parking pawl, a motor torque is applied after the actuator is activated to rotate the drive motor by a predetermined angle. This prevents the drive motor from becoming hot and eliminates the need for phase alignment and learning processes between the parking gear and the parking pawl. As a result, the cost of the control structure is not increased and the vehicle can be prevented from sliding down a slope.

[0013] Furthermore, in the vehicle control device, the specified angle is preferably the maximum angle α of rotation of the parking gear 24 until it engages with the parking pawl 40. max Therefore, by setting the specified angle to the maximum angle, the gear state in which the parking gear meshes with the parking pawl can be reliably obtained through simple control.

[0014] Furthermore, in the vehicle control device, the motor angle control component 48 preferably calculates the motor torque required to rotate the parking gear 24 by a predetermined angle and uses it as the target torque, gradually increasing the motor torque in a manner that reaches the target torque within a predetermined time. Thus, high-precision control can be implemented by monitoring the relationship between the applied motor torque and the cumulative angle.

[0015] Furthermore, in the vehicle control device, preferably, the motor angle control component 48 determines that the parking gear 24 has engaged with the parking pawl 40 and terminates control when there is no increase in the rotation angle of the drive motor 8 for a certain period of time relative to the increase in motor torque. This shortens the motor angle control time.

[0016] Furthermore, the vehicle control device preferably includes a parking action permission determination component 48, which detects the vehicle speed v after the parking lock operation component 58 is operated, and determines whether the actuator 44 is allowed to operate based on the detected vehicle speed. This prevents unnecessary parking actions when the vehicle is moving on a slope.

[0017] Furthermore, the vehicle control device preferably includes a motor angle control execution determination unit 48, which, after the parking action permission determination unit 48 permits the parking action and the actuator 44 operates, determines whether to execute motor angle control performed by the motor angle control unit 48 based on the slope detected by the slope detection unit 56. This prevents unexpected vehicle behavior, such as excessive slippage (referring to a slight upward movement of the vehicle along a slope, hereinafter the same).

[0018] [The effects of the invention]

[0019] According to the present invention, there is no adverse condition caused by the overheating of the drive motor, and there is no increase in the cost of the control structure, which can suppress the vehicle from sliding downhill when parking on a slope. Attached Figure Description

[0020] Figure 1 This is a schematic structural diagram of a vehicle equipped with a vehicle control device according to an embodiment of the present invention.

[0021] Figure 2 This is a control block diagram that is part of the vehicle control system.

[0022] Figure 3 A diagram illustrating the specific meshing state of the parking gear and parking pawl in a vehicle control device.

[0023] Figure 4 This is a schematic diagram used to illustrate the force relationships acting on a vehicle on a ramp.

[0024] Figure 5 A flowchart illustrating the control actions performed by the vehicle control unit to suppress slippage.

[0025] Figure 6 This is a time flow diagram representing the control actions performed by the vehicle control unit to suppress slippage.

[0026] Figure 7 This is a timeline diagram used to illustrate the problems with the prior art.

[0027] [Explanation of Symbols]

[0028] 1: Vehicle control device;

[0029] 2: Vehicles;

[0030] 8: Traction motor (drive motor);

[0031] 22: Drive shaft;

[0032] 24: Parking gears;

[0033] 40: Parking pawl;

[0034] 44: Actuator;

[0035] 46: Hybrid electronic control unit;

[0036] 48: CPU (motor angle control unit, parking action permission determination unit, motor angle control execution determination unit);

[0037] 56: Tilt angle detection sensor (slope detection component);

[0038] 60: Analyzer (rotation angle detection component);

[0039] n: a certain amount of time;

[0040] α max : Specified angle (maximum angle). Detailed Implementation

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0042] Figure 1 This is a schematic structural diagram of a vehicle equipped with a vehicle control device according to an embodiment of the present invention. As shown in the figure, the vehicle 2, which is a hybrid automobile, includes an engine 4, a generator 6, a traction motor 8 as a drive motor, a differential 10, and a parking mechanism 12. A gear 16 fixed to the drive shaft 14 of the engine 4 meshes with a gear 20 fixed to the main shaft 18 of the generator 6. A parking gear 24 of the parking mechanism 23 is fixed to the drive shaft 22 connected to the rotor of the traction motor 8, and a transmission gear 28 is also fixed thereon, which meshes with a gear 26 driven by the rotation of the engine 4. The transmission gear 28 meshes with an idler gear 30, and a gear 32 coaxially fixed to the idler gear 30 meshes with the final gear 34 of the differential 10. Reference numeral 36 indicates an axle (rotating shaft) that transmits power from the differential 10 to the left and right drive wheels 38.

[0043] Figure 2 This is a control block diagram as part of the vehicle control system. It consists of a traction motor 8 and a parking mechanism 12, as well as... Figure 2The vehicle speed sensor 54, tilt angle detection sensor 56, P switch (parking lock operation element) 58, resolver (rotation angle detection component) 60, brake sensor 62, electronic control unit 46, etc. shown constitute the vehicle control device 1 of this embodiment.

[0044] Figure 3 A diagram illustrating the specific meshing state of the parking gear and parking pawl in a vehicle control system. (Example) Figure 1 and Figure 3 As shown, the parking mechanism 12 includes: a parking gear 24; a parking pawl 40 engaging with the parking gear 24; and a parking lever 42. Figure 1 The arrow moves in the X direction, causing the parking pawl 40 to move to a position where it engages with the parking gear 24 and locks the drive shaft 22, and to a position where it is unlocked; and the actuator 44 drives the parking lever 42 in the X direction.

[0045] like Figure 2 As shown, the vehicle control device 1 includes a hybrid electronic control unit (hereinafter referred to as the electronic control unit) 46 that controls the entire vehicle. The electronic control unit 46 is configured as a microcomputer, which includes a central processing unit (CPU) 48, a read-only memory (ROM) 50 for storing processing programs, a random access memory (RAM) 52 for temporarily storing data, and input-output (I / O) interfaces (not shown). A vehicle speed sensor 54, a tilt angle detection sensor 56, a P switch 58, an analyzer 60, and a brake sensor 62 are connected to the electronic control unit 46. The traction motor 8 is connected to the electronic control unit 46 via a motor ECU (motor electronic control unit) 7.

[0046] Vehicle speed sensor 54 detects the vehicle speed v of vehicle 2 and outputs a signal corresponding to the detected vehicle speed v to the CPU 48 of electronic control unit 46. CPU 48 functions as a parking action permission determination component, determining whether actuator 44 is permitted to operate based on the vehicle speed value detected by vehicle speed sensor 54. Tilt angle detection sensor 56, which functions as a slope detection component, includes an acceleration sensor or gyroscope sensor, etc., detects the gravitational acceleration of vehicle 2 in the horizontal and vertical directions, and outputs a signal corresponding to the detected gravitational acceleration to CPU 48 of electronic control unit 46. CPU 48 functions as a motor angle control component, causing traction motor 8 to rotate at a predetermined angle corresponding to the slope detected by tilt angle detection sensor 56 after actuator 44 operates.

[0047] When the driver of the vehicle presses the P switch (parking switch) 58, which serves as the parking lock operation element, a signal to activate the actuator 44 is output to the CPU 48 of the electronic control unit 46. The CPU 48 functions as a motor angle control execution determination unit, determining whether to execute motor angle control based on the slope detected by the tilt angle detection sensor 56 after the actuator 44 is activated. The analyzer 60, acting as a rotation angle detection unit, detects the rotation angle of the traction motor 8 and outputs the detected angle to the CPU 48 of the electronic control unit 46. The brake sensor 62 detects the opening and closing of the brake pedal (not shown) and outputs a signal corresponding to the detected state to the CPU 48 of the electronic control unit 46.

[0048] like Figure 3 As shown, the parking pawl 40 is configured to rotate freely about the rotation axis 66 and be supported, accompanied by the parking lever 42 (see reference). Figure 1 The parking lever 42 presses and rotates the vehicle as it moves. The parking gear 24 has equally spaced recesses 24a along its circumference. The protrusions 40a of the parking pawl 40 engage with these recesses, locking the drive shaft 22. When the brake is off and motor torque is applied to rotate the traction motor 8, the parking gear 24 will always engage with the gear within an angle α corresponding to its tooth angle. Depending on the engagement timing with the parking pawl 40, it may rotate up to α. max That is, for example, when the angle α is 60°, it becomes α. max =60°. Therefore, in this embodiment, α max The specified angle is set until the parking gear 24 is reliably connected to the gear. Furthermore, Figure 1 The parking gear 24 and parking pawl 40 are schematically shown in the diagram.

[0049] Figure 4This is a schematic diagram illustrating the force relationships acting on a vehicle on a slope. As shown in the diagram, if the vehicle weight of vehicle 2 is set as M [kg], the tire diameter as R [m], the slope (climbing slope) as θ [deg], the rigidity of the drive shaft 36 obtained by combining the left and right sides as k [Nm / deg], and the torsional angle of the drive shaft 36 as β [deg], then the torsional force of the drive shaft 36 indicated by the upward arrow is kβ / R, the downward sliding force indicated by the downward arrow is Mgsinθ, and the torsional angle of the drive shaft 36 is β=Mgsinθ / k. Dr / sh in the diagram refers to the drive shaft. After parking is locked using the parking mechanism 12, without applying the parking brake, the torsional angle β of the drive shaft 36 after the brake is closed is determined based on the vehicle weight, the climbing slope, the tire diameter, and the rigidity of the drive shaft 36. Without any control, if the parking brake is not applied, the vehicle slides down the distance expressed by the following formula (1). In equation (1), i is the ratio of the rotational speed of axle 36 to the rotational speed of drive shaft 22.

[0050] [Number 1]

[0051]

[0052] Reference Figure 5 and Figure 6 The control operation of the vehicle control device 1 of this embodiment for preventing the slippage will be described.

[0053] Figure 5 This is a flowchart illustrating the control actions performed by the vehicle control unit to suppress slippage. Furthermore, Figure 6 This is a time flow diagram representing the control actions performed by the vehicle control unit to suppress slippage. For example... Figure 5As shown, firstly, the CPU 48 determines whether the brake is on based on the signal from the brake sensor 62 (step S1). If the brake is on (yes in step S1), it determines whether the P switch 58 has been pressed by the driver (step S2). If the brake is off (no in step S1), it returns to step S1. If the P switch 58 is pressed (yes in step S2), the CPU 48 functions as a parking action permission determination unit, determining whether the actuator 44 is allowed to operate (step S3). If the P switch 58 is not pressed (no in step S2), it returns to step S2. The parking action permission determination is based on whether the vehicle speed is less than a specified speed v. That is, the CPU 48 compares the vehicle speed detected by the vehicle speed sensor 54 with the specified speed v pre-stored in the ROM 50 and makes a determination. If the detected vehicle speed is above the specified speed v (no in step S3), it returns to step S3. If the detected vehicle speed is less than the specified speed v, the CPU 48 sends a working signal to the actuator 44 to allow the actuator 44 to operate (step S4). Figure 6 As shown, there is a response delay from when switch P 58 is turned on until actuator 44 starts working.

[0054] Next, the CPU48 functions as a motor angle control execution determination unit. After the actuator 44 is activated, it determines whether to execute motor angle control performed by the motor angle control unit (CPU48) based on the slope detected by the tilt angle detection sensor 56 (step S5). That is, the CPU48 compares the slope detected by the tilt angle detection sensor 56 with a predetermined slope d pre-stored in the ROM 50. If the detected slope is greater than or equal to the predetermined slope d, "TRC angle control" is initiated, that is, the traction motor 8 is rotated at a predetermined angle corresponding to the slope detected by the tilt angle detection sensor 56 (step S6). Figure 6 The TRC angle control is displayed as motor control. If the detected slope is less than the specified slope d (NO in step S5), return to step S5. In TRC angle control, after the actuator 44 is activated, the traction motor 8 is rotated in the opposite direction to the direction in which the vehicle 2 slides down, reducing the amount of sliding down the vehicle 2 to the amount expressed by the following formula (2).

[0055] [Number 2]

[0056]

[0057] In order to rotate the parking gear 24 by a specified angle while the brake is open, the torque T of the traction motor 8, as expressed in the following formula (3), is required. TRC .like Figure 6As shown, the torque is 0 at the start of TRC angle control. The CPU48, which is the motor angle control component, calculates the motor torque required to rotate the parking gear 24 by a specified angle using equation (3) and uses it as the target torque. The motor torque is gradually increased in a way that the target torque is reached within a specified time.

[0058] [Number 3]

[0059]

[0060] Next, the CPU48, which is the motor angle control component, monitors the cumulative value of the detected angle of the traction motor 8 from the analyzer 60, and determines whether the specified angle α has been reached. max (Step S7). At the specified angle α... max In this case, the parking gear 24 is considered to be engaged, and TRC angle control ends. If the specified angle α is not reached... max If the condition is "No" in step S7, determine whether the cumulative angle does not increase for a certain period of time n relative to the increase in motor torque (whether it is a certain period of time n) (step S8). If the condition is "Yes" in step S8, determine that the parking pawl 40 has engaged with the parking gear 24 (the gear is connected), and end the TRC angle control. At this time, when the specified angle α is reached... max The front gear has been established. That is, the time it takes for the parking gear 24 to reach the connecting gear is shorter than specified. If the time during which the cumulative angle does not increase does not last for a certain period of time (NO in step S8), return to step S8.

[0061] As described above, TRC angle control can reduce the amount of gliding, but it is not good to cause unpredictable behaviors such as excessive gliding. Therefore, within the conditions expressed by equation (4) below, CPU48 does not allow TRC angle control to be executed in step S5. Thus, it will not cause the driver any unexpected panic or anxiety.

[0062] [Number 4]

[0063]

[0064] As described above, in the vehicle control device 1 of this embodiment, instead of pre-aligning the phase of the parking gear and the parking pawl by rotating the traction motor as in the prior art, TRC angle control (motor control) is performed to reliably engage the parking gear 24. Therefore, regardless of whether there is a phase deviation between the parking gear 24 and the parking pawl 40, the parking gear 24 can be reliably engaged within a specified angle. Thus, motor control can begin after the actuator 44 is activated, without having to remain in a standby state with applied motor torque until the P switch 58 is pressed, as in the prior art. As a result, the motor temperature will not become too high and unable to apply torque. Moreover, there is no need to rotate the traction motor 8 to pre-align the phase of the parking gear 24 and the parking pawl 40, and there is no need for a learning process, thus avoiding an increase in control costs and suppressing rollback when parking on a slope.

[0065] The embodiments of the present invention have been described above, but the present invention is not limited to the described embodiments, and various modifications can be made within the scope of the technical concept described in the claims, specification, and drawings. For example, the embodiments described the case where vehicle 2 is parked on an uphill slope, but the same effect can be obtained when parking on a downhill slope.

Claims

1. A vehicle control device, characterized in that, include: A drive motor used to drive a vehicle; A drive shaft is connected to the drive motor; The parking gear is fixed to the drive shaft; A parking pawl engages with the parking gear; The actuator, through the operation of the parking locking operating element, moves the parking pawl to a locked position and a locked-out position by engaging the parking gear to lock the drive shaft; Inclination detection component, used to detect the incline of a vehicle; A rotation angle detection component detects the rotation angle of the drive motor; as well as The motor angle control component, after the actuator moves the parking pawl to the locked position, causes the drive motor to rotate by a predetermined angle, the predetermined angle corresponding to the slope detected by the slope detection component. The motor angle control component calculates the motor torque required to rotate the parking gear by the specified angle and uses the motor torque as the target torque, gradually increasing the motor torque in a manner that reaches the target torque within a specified time.

2. The vehicle control device according to claim 1, characterized in that, The specified angle is the maximum angle at which the parking gear rotates until it engages with the parking pawl.

3. The vehicle control device according to claim 2, characterized in that, If the motor angle control component determines that the parking gear has engaged with the parking pawl and terminates control when there is no increase in the rotation angle of the drive motor relative to the increase in the motor torque, but no increase in the rotation angle of the drive motor over a certain period of time.

4. The vehicle control device according to any one of claims 1 to 3, characterized in that, include: The parking action permission determination component detects the vehicle speed after the parking locking operation is performed, and determines whether the actuator is allowed to operate based on the detected vehicle speed.

5. The vehicle control device according to claim 4, characterized in that, include: The motor angle control execution determination unit determines whether to execute the motor angle control performed by the motor angle control unit based on the slope detected by the slope detection unit after the parking action permission determination unit allows the parking action and the actuator operates.

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