KR20200001789A - Vehicle equipped with electric motor and method for parking control thereof - Google Patents

Abstract

The present invention relates to a vehicle capable of preventing contact with a bump during parking or damage to the bump or a drive system due to an accident in which a person goes under the wheels thereof, on account of creep torque simulation of an electric motor in the vehicle having the electric motor, and a parking control method for the vehicle According to an embodiment of the present invention, a parking control method for a vehicle simulating creep torque with an electric motor comprises the steps of: detecting an object exerting reaction on wheels thereof in a parking direction during parking; primarily controlling the creep torque until at least one among the wheels reaches from parallel points, at which the wheels are stopped or start to rotate in a direction opposite to the parking direction, to target locations in the direction opposite to the parking direction, when the vehicle slows down from the time when the object is detected to the parallel points; and removing the creep torque when a brake pedal is operated after the wheels reach the target locations.

Description

VEHICLE EQUIPPED WITH ELECTRIC MOTOR AND METHOD FOR PARKING CONTROL THEREOF}

The present invention relates to a vehicle and a parking control method thereof capable of preventing damage to the jaw or the driving system due to the creep contact or parking due to creep torque simulation of the electric motor in an automobile having an electric motor.

Driving is also important, but driving usually ends with parking, so the parking process is no less important than driving. Various devices are used in this parking process.

For example, a parking brake or a P stage of a transmission is used to prevent a vehicle that has reached a parking position from moving at that position. This will be described with reference to FIGS. 1 and 2.

1 is a view illustrating the operation principle of the P stage of a general transmission, and FIG. 2 is a view for explaining an operation principle of a general parking brake.

First, referring to FIG. 1, the P stage of the transmission causes the protrusion 131 of the parking pawl 130 to be caught by the gear 120 fixed to the rotation shaft 110 of the transmission output stage, thereby rotating the shaft of the transmission output stage. Mechanically secure the 110 to prevent the movement of the car. However, when a large load is applied to the rotating shaft 110, the protrusion 131 of the parking pawl 130 may be damaged, and the protrusion 131 may be gradually worn down due to cumulative use, thereby losing its function.

Next, the parking brake is useful for preventing the movement of the vehicle, especially when the vehicle is standing for a long time or when the slope is severe, and may be used for emergency in the event of a foot brake failure, and has an operation circuit independent of the foot brake. Referring to FIG. 2, the parking brake includes a pad 220 that closely contacts the inner circumferential surface of the drum 210 when the wire 230 is operated in the drum 210 and the drum 210 to prevent rotation of the drum. The drum brake system is mainly used.

In addition, in the parking process, a parking assistance system, which is a device that notifies the driver of obstacles with an alarm sound by monitoring a space in the range of about 0.25 m to 1.5 m using 4 to 6 ultrasonic sensors provided in the front or rear bumpers ( Parking Assistant System (PAS) may be used. Such parking assistance systems usually consist of ultrasonic sensors and warning devices. Recently, a smart parking assistant system (SPAS) has been introduced, which checks whether there is an appropriate parking space and automatically controls steering.

Meanwhile, the demand for eco-friendly vehicles is increasing due to the continuous improvement of fuel efficiency for automobiles and the tightening of emission regulations in each country.As a realistic alternative, hybrid electric vehicles / plug-in hybrid electric vehicles , HEV / PHEV, and Electric Vehicle (EV) are available.

Hybrid vehicles (PHEV / HEV) and electric vehicles (EV) are commonly equipped with electric motors. In particular, during parking, the electric motors are designed to simulate the low speed characteristics of automobiles with internal combustion engines and automatic transmissions (A / T). Creep torque control is applied. Here, the creep torque refers to the torque that the idle torque of the engine is transmitted to the drive shaft through the torque converter even when the accelerator pedal is not pressed in an internal combustion engine vehicle having an automatic transmission. The phenomenon of driving. When a creep occurs, a car usually runs at 10 kph or less. In an eco-friendly car, the engine is usually turned off and driven only by an electric motor for fuel efficiency at low speeds, so the creep is simulated by an electric motor. 3 shows an example of the form of creep torque control of a vehicle with a general electric motor.

Referring to FIG. 3, the electric motor of the eco-friendly vehicle operates with a positive torque up to a certain vehicle speed in a situation where the accelerator pedal is not operated, and operates with a negative torque after the constant vehicle speed to simulate rolling resistance. Here, a part operating with positive torque corresponds to a creep torque region that simulates creep torque. Here, the horizontal axis may be a brake pedal sensor (BPS) value instead of the vehicle speed.

By the way, due to the creep torque of the eco-friendly car, a problem may occur due to the parking barrier. This will be described with reference to FIG. 4.

4 is a view for explaining a problem that may occur in a parking situation of a general eco-friendly car. In FIG. 4, it is assumed that the parking process is performed by the rear parking method, but the parking brake and the P-stage operation are performed as the rear wheel 310 touches the parking slip prevention 320.

First, when the parking brake is operated after the P stage operation or when the P stage operation is performed after the parking brake is operated, the tire of the rear wheel 310 pushes the jaws 320 in common as shown in FIG. do. In this case, the former may be damaged due to the load on the P gear, and when the P gear is released, transmission shock may occur. Even in the latter case, the tire pushes the jaws, and thus the durability of the parking brake may be reduced due to the continuous load. If the parking brake is pushed over time, the same problem may occur as the former.

In addition, in extreme cases, the rear wheel 310 may ride over the jaw 320 due to the creep torque as shown in FIG. In this case, each brake means may be subjected to a larger load than the situation shown in FIG. 4 (a), which is particularly problematic when the driver in the front seat is unaware of this.

In order to prevent the above-mentioned situation, after the rear wheel 310 recognizes the touch of the prevention jaw 320 and shifts to the N stage, the contact state of the rear wheel 310 and the prevention jaw 320 is released, and then the parking brake or the P stage operation is performed. There is also a method, but the operation is inconvenient.

Accordingly, there is a need for a method for detecting a bump when parking and preventing damage to the driving system or the bump through appropriate control.

The present invention is to provide a vehicle and a parking control method therefor capable of preventing damage to the parking barrier or driving system due to contact with the parking barrier when the vehicle is equipped with an electric motor.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In order to solve the above technical problem, a parking control method of a vehicle that simulates creep torque by an electric motor according to an embodiment of the present invention, the step of detecting an object that exerts a reaction force on the wheel in the parking progress direction when parking ; When the vehicle decelerates from the point of time when the object is detected to the equilibrium point where the wheel stops or starts to rotate in the opposite direction to the parking direction, from the balance point to the opposite direction of the parking direction. First controlling the creep torque until the at least one wheel reaches a located target position; And after the brake pedal is operated after reaching the target position, removing the creep torque.

In addition, the automobile that simulates the creep torque by the electric motor according to an embodiment of the present invention, the sensing unit for detecting an object that exerts a reaction force on the wheel in the parking proceeding direction when parking; And when the vehicle decelerates from the time point at which the object is detected to the equilibrium point where the wheel stops or starts to rotate in the opposite direction to the parking advance direction, from the equilibrium point to the opposite direction to the parking advance direction. The creep torque may be controlled to control the creep torque until the at least one wheel reaches a target position located in the control unit, and the brake pedal may be removed when the brake pedal is operated after reaching the target position.

In the vehicle having the electric motor according to at least one embodiment of the present invention configured as described above, damage to the drive system may be prevented by creep torque control in consideration of the parking slippage bump during the parking process.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

1 is a view for explaining the operation principle of the P stage of the general transmission, Figure 2 is a view for explaining the operation principle of the general parking brake, respectively.
3 shows an example of the form of creep torque control of a vehicle with a general electric motor.
4 is a view for explaining a problem that may occur in a parking situation of a general eco-friendly car.
5 is a block diagram showing an example of a vehicle configuration according to an embodiment of the present invention.
6 is a graph illustrating an operating state of each component in a creep torque control process according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating an example of a creep torque control process.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, parts denoted by the same reference numerals throughout the specification means the same components.

In an automobile equipped with an electric motor according to an embodiment of the present invention, when the contact with the parking bump is sensed, it is proposed to induce the movement of the parking bump as the wheel is not pressed by the creep torque control.

First, a configuration of an automobile for performing creep torque control according to an embodiment of the present invention will be described with reference to FIG. 5.

5 is a block diagram showing an example of a vehicle configuration according to an embodiment of the present invention. For convenience, in the following drawings including FIG. 5, it is assumed that the vehicle equipped with the electric motor is a hybrid vehicle (PHEV / HEV). However, it will be apparent to those skilled in the art that except for a configuration (for example, an engine controller) applied only to a hybrid vehicle, the remaining configuration may be similarly applied to an environmentally friendly vehicle such as an electric vehicle (EV) or a hydrogen fuel cell vehicle (FCEV).

Referring to FIG. 5, a hybrid vehicle according to an embodiment may include an engine controller (EMS) 510 for controlling an internal combustion engine, a motor controller 520 (MCU) for controlling an electric motor, and hydraulic braking. Electronic Brake System (EBS: 530) for controlling, Electronic Stability Controller (ESC: 540) for performing posture control and Hybrid Controller (HCU: 550), which is an upper controller of the aforementioned controllers. It may include. Of course, in the case of an electric vehicle (EV) that is not a hybrid vehicle, the engine controller 510 may be omitted, and the role of the engine controller 510 may be replaced by the motor controller 520 or another controller, and the hybrid controller 550. May be replaced with a vehicle control unit (VCU).

The function of each component will now be described in terms of control of creep torque during parking.

First, the engine controller 510 senses the position (θ) and the speed (ω) of the wheel, and detects whether the accelerator pedal is manipulated through the accelerator pedal sensor (APS) value.

The motor controller 520 receives the creep torque command from the hybrid controller 550 and controls the electric motor to output a torque corresponding to the command.

The brake controller 530 applies a braking force to the hydraulic brake in response to the brake pedal sensor (BPS) value.

The electronic posture controller 540 may detect the inclination, and in some cases, the inclination value may be replaced with the navigation information.

Meanwhile, the hybrid controller 550 may receive a variety of information from each of the controllers 510 to 540 described above, perform calculations and determinations necessary for creep torque control, and transmit a creep torque command to the motor controller 520. For example, the hybrid controller 550 is a parking jam bump detection unit 551 and the parking jam bump detection unit 551 to detect the presence of the parking jam bumps / wheels contact or presence / contact of the parking jam bumps It may include a creep torque calculation unit 553 for calculating a creep torque suitable for preventing damage to the drive system according to the detection.

Hereinafter, a creep torque control process will be described with reference to FIGS. 6 and 7 based on the aforementioned vehicle structure.

6 is a graph illustrating an operating state of each component in a creep torque control process according to an embodiment of the present invention, and FIG. 7 is a flowchart illustrating an example of a creep torque control process.

Referring first to FIG. 6, four graphs are shown. In order from top to bottom, the vertical axis represents the brake pedal value, the amount of creep torque, the hydraulic braking amount, and the wheel's relative position with respect to the parking barrier, and the horizontal axis shows four graphs sharing each other. It represents the time divided into five sections from to ⑤.

In the section, the vehicle moves in the parking direction (for example, backward direction if it is rear parking), and the acceleration of the vehicle can be ignored and the speed is very low until the wheel reaches the bump. In other words, the acceleration is negligible as the wheels reach the bumps. Therefore, the current exercise state satisfies Equation 1 below.

는 지면의 등판각을,

는 차량의 등가 관성(mR^2에 해당)을,

은 크립토크를,

은 타이어의 구름 저항을,

는 바퀴의 각가속도를 각각 나타낸다. 이때, 구름저항

은 자동차가 수평 노면 위를 굴러 이동할 때 받는 저항의 총합으로 타이어를 변형시키는 저항/자동차 각부의 마찰/노면을 변형시키는 저항 등으로 구성되며 보통 차량 중량의 4~5%의 값을 갖는다.In Equation 1, m is the mass of the vehicle, R is the radius of the tire,

The elevation of the floor,

Is the equivalent inertia of the vehicle (mR ^ 2),

Is the cryptocurrency,

The rolling resistance of tires,

Are the angular accelerations of the wheels respectively. At this time, rolling resistance

Is the total resistance received when a vehicle rolls on a horizontal road, and is composed of resistance to deform tires, friction of various parts of the vehicle, and resistance to deform the road, and usually have a value of 4 to 5% of the weight of the vehicle.

② In the section, the following equation 2 is satisfied according to the tire elastic modulus k from the moment the wheel touches the bump.

That is, Equation 2 means that the vehicle decelerates at the speed of reaching the bump while moving at a constant speed. Since the hybrid controller 550 may determine that the wheel touches the jaw from the moment when the equation 1 is not satisfied, the hybrid controller 550 starts the measurement of Δθ and uses the RMS value based on the RMS method until the wheel stops. Can be calculated. In this case, the minimum data for calculating the value is preferably 4 sampling time, but all data up to the equilibrium point may be used to increase the accuracy. Of course, as is generally known, if the R-square value of RMS is more than 80%, it can be judged that the data can be trusted.If the R-square value is more than 80%, the creep torque variable control is performed immediately without reaching the equilibrium point. May be

Accordingly, the reaction torque kΔθ between the tire and the jaw is added from the moment of contact with the jaw to satisfy Equation 3 below. Where k is the elastic modulus of the wheel and Δθ is the angle rotated from the moment when the wheel touches the jaws.

In this case, Equation 3 may be approximated as Equation 4 below.

This, in turn, means that the wheel moves in a decelerating manner to an equilibrium point where it stops the cloud in the backward direction (or begins to rotate in the opposite direction) exponentially according to the second differential equation.

③ When the wheel reaches the balancing point in the section, the following Equation 5 is satisfied.

In Equation 5, since the wheel moves in the opposite direction to the parking direction from the moment the equilibrium point is reached, the sign of the rolling resistance is reversed.

The hybrid controller 550 thus adjusts the creep torque to satisfy Equation 6 below until the wheel meets the target position (e.g., Δθ (≒ 0)) (i.e., until the wheel returns to the position before reaching the jaw). Can be controlled.

In Equation 6, + ε means movement with very small acceleration. If this value is exactly 0, the vehicle will not be able to move because it does not have acceleration, and if it is too large, it will have forward acceleration, which may cause the driver to feel heterogeneous. Therefore, since the moving distance is a few cm, it is desirable to move the vehicle with a very small acceleration in consideration of the driver's sensitivity.

④ In the section, the creep torque may be maintained to move the vehicle to an equilibrium state after moving to a preset position (that is, satisfying Δθ (≒ 0)).

⑤ In the section, according to the driver's brake pedal operation, the creep torque may be released and the hydraulic braking torque may be applied.

In summary, in the sections ① to ②, it may be regarded as a process of detecting the parking jam bar by the parking jam bar detection unit 551, and after the section ③, the creep torque computing unit 553 may calculate the creep torque. . Of course, the process of measuring the elastic modulus of the wheel in the section ② may be performed by the creep torque calculation unit 553.

7 is a flowchart illustrating the entire parking control process including the aforementioned creep torque control process.

Referring to FIG. 7, first, it may be determined whether creep torque control is performed in consideration of a parking barrier and setting a smart parking assistance system (SPAS) according to an embodiment (S710 and S720). Here, the reason for determining whether the smart parking assistance system is set is to prevent a situation in which the vehicle does not reverse by misrecognizing the acceleration change due to the slope as the parking barrier when the driver intends to climb in the reverse direction. In this case, this process may be omitted.

Next, when the parking jam bump is detected (ie, when the behavior of the car satisfies Equation 1 and then satisfies Equation 2) (S730), the accelerator pedal is not operated (ie, APS == 0). When the driver's brake pedal manipulation amount is within a range for generating creep torque (ie, 0 <BPS <BPS _{creep = 0} ) (S740), the above-described creep torque control process may be performed (S750).

Here, step S740 takes into account that the creep torque control may be meaningless when the brake pedal operation amount of the driver is large and a braking torque is generated or when the driver operates the accelerator pedal with an acceleration will.

By the creep torque control according to the above-described embodiment, not only the driving system of the vehicle can be protected from the load due to the contact of the parking bump and the wheel, but also the damage of the parking bump cannot be prevented. In addition, the emotional discomfort of the driver can be reduced by reducing the impact when the P-stage is released, and the merchandise of the vehicle can be improved, and the contact situation with surrounding objects due to the phenomenon of riding over the parking barrier can be prevented.

In addition, the present invention described above is based on an eco-friendly vehicle having an electric motor to simulate creep torque, but the creep torque is not generated naturally by a power source such as an engine, and thus creep torque through another output source such as a motor. If the car is not limited to any kind of car can be applied. In addition, the parking slipper is also an example, and any object that exerts a reaction force on at least one wheel in the parking proceeding direction during parking (for example, stones, ground cracks, etc.) is not limited to any form.

In addition, the present invention described above can be embodied as computer readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable media include hard disk drives (HDDs), solid state disks (SSDs), silicon disk drives (SDDs), ROMs, RAM, CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and the like. There is this.

Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all conversions within the equivalent scope of the invention are included in the scope of the invention.

Claims (19)

In a parking control method for a car that simulates creep torque with an electric motor,
Detecting an object exerting a reaction force on the wheel in the parking progress direction when parking;
When the vehicle decelerates from the point of time when the object is detected to the equilibrium point where the wheel stops or starts to rotate in the opposite direction to the parking direction, from the balance point to the opposite direction of the parking direction. First controlling the creep torque until the at least one wheel reaches a located target position; And
If the brake pedal is operated after reaching the target position, removing the creep torque. The method of claim 1,
The detecting step,
Detecting a change in the equivalent inertia of the vehicle. The method of claim 1,
The first controlling step,
And measuring the angle at which the wheel is rotated from the time when the object is detected. The method of claim 3, wherein
Calculating an elastic modulus of the wheel based on the measured angle until the wheel reaches the equilibrium point. The method of claim 4, wherein
The target position includes a point at which the measured angle becomes zero,
The first controlling step,
Parking control method is performed based on the calculated elastic modulus. The method of claim 1,
And controlling the creep torque so that the creep torque at the time point when the equilibrium point is reached is maintained until the brake pedal is operated. The method of claim 1,
The first controlling step,
A parking control method, which is performed when creep torque control and parking assistance system are set at the time of parking. The method of claim 1,
The first controlling step,
And a brake pedal operation in a range where the creep torque is not generated or is stopped when an accelerator pedal operation is detected. The method of claim 1,
The object for exerting a reaction force includes a parking barrier. A computer-readable recording medium having recorded thereon a program for executing the parking control method according to any one of claims 1 to 9. In an automobile that simulates creep torque with an electric motor,
A sensing unit for sensing an object exerting a reaction force on the wheel in the parking proceeding direction when parking; And
When the vehicle decelerates from the point of time when the object is detected to the equilibrium point where the wheel stops or starts to rotate in the opposite direction to the parking direction, from the balance point to the opposite direction of the parking direction. And a creep torque calculating unit for controlling the creep torque until the at least one wheel reaches a target position located, and removing the creep torque when the brake pedal is operated after reaching the target position. The method of claim 11, wherein
The detection unit,
And detecting the object using a variation of the equivalent inertia of the vehicle. The method of claim 11, wherein
The creep torque calculation unit,
And measuring the angle at which the wheel is rotated from the time when the object is detected. The method of claim 13,
The creep torque calculation unit,
Calculating an elastic modulus of the wheel based on the measured angle until the wheel reaches the equilibrium point. The method of claim 14,
The target position includes a point at which the measured angle becomes zero,
The creep torque calculation unit,
And controlling the creep torque based on the calculated elastic modulus. The method of claim 11, wherein
The creep torque calculation unit,
And the creep torque at the time point when the balance point is reached is maintained until the brake pedal is operated. The method of claim 11, wherein
The creep torque calculation unit,
A car, which performs the control of the creep torque when the creep torque control function and the parking assistance system are set during parking. The method of claim 11, wherein
The creep torque calculation unit,
The brake pedal operation of the range in which the creep torque is not generated is detected, or stopping the control of the creep torque when the accelerator pedal operation is detected. The method of claim 11, wherein
The reacting object comprises a parking barrier.

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