KR102206371B1 - Method for deciding and recovering motor lock of rear wheel steering apparatus - Google Patents

Abstract

The present invention provides a method of determining whether a rear wheel steering motor is in a locked state due to its own factor or an external factor in a vehicle using rear wheel steering, informing the driver of a failure, and controlling to return to a normal state. For this purpose, a method for determining and restoring a motor lock of a rear wheel steering apparatus according to the present invention includes the steps of: (a) determining whether the current consumption of the motor is greater than or equal to a set value; (b) determining whether the motor is locked when the current consumption of the motor is greater than or equal to a set value; (c) when the motor is in a locked state, determining whether or not the locking time of the motor is greater than or equal to a set time;

Description

TECHNICAL FIELD [Method for deciding and recovering motor lock of rear wheel steering apparatus]

The present invention relates to a method of controlling to return to a normal state by determining whether a failure has occurred in a vehicle using rear wheel steering when a rear wheel steering motor is locked due to its own or external factors.

Steering devices applied to general automobiles are generally configured to be able to steer through the front wheels. In this case, when turning while driving at high speed, the size is proportional to the centrifugal force, that is, the turning speed, and inversely proportional to the turning radius. As the force of the turn acts outward, the driver must reduce the speed or increase the turning radius.

As described above, deceleration or increasing the turning radius during turning is not effective, so recently, as a means to improve turning driving performance, a technology for attaching a steering device to the rear wheels as well as the front wheels has been developed. It is being applied to.

In the case of a rear wheel steering vehicle as described above, a steering method using a lead screw is widely used, unlike a ball screw method employed in the conventional front wheel steering.

Since such a rear-wheel steering vehicle does not have a column and a steering wheel as in a front-wheel steering vehicle, steering is performed using a lead screw and a motor, and thus the volume can be reduced by reducing the motor volume. Has.

In other words, it is controlled using a communication method such as CAN (Controller Area Network) communication without a steering wheel (a standard communication standard designed to allow microcontrollers or devices to communicate with each other without a host computer in a vehicle).

However, such a rear wheel steering device may cause mechanical lock on one side when excessive steering proceeds due to the characteristics of the lead screw.

This may be caused by internal factors inside the vehicle or by external factors.For example, when the target steering position is input in the form of a step when driving the rear wheel steering device, it is overshoot. As a result, the lead screw may proceed further than the target value and may be locked at one end and may be locked due to an error inside the steering system.

In addition, in the case of locking due to external factors, for example, when the rear wheel steering system is terminated in a controlled (steered) state to one side (terminated without returning to its original state), when the steering system is turned on again, the tire May not be able to move due to obstacles. In this case, current control (torque control) of the motor is performed to return to the initial steering state, but it may not return to the initial steering position due to external obstacles. In this case, the current applied to the motor is continuously consumed, so that an overcurrent flows in the electronic control unit (ECU) or a problem that the motor is overheated may occur.

As another external factor, a foreign substance may be caught in the middle of driving the rear wheel steering apparatus, making it impossible to operate, or when the vehicle is traveling at a low speed, the friction between the road surface and the tire may increase, making steering control impossible. Even in such a case, an overcurrent is generated in order to continuously control the current, resulting in a problem that the electronic control unit (ECU) is burned out due to overheating or causes overheating of the motor.

In this way, if the lock occurs due to the rear wheel steering system itself or external factors, current control is continuously performed to control the return to the initial steering position, causing battery performance degradation, and electronic control. There was a serious problem that caused the unit (ECU) and motor performance to deteriorate and overheat to occur.

Korean Patent Publication No. 1994-0003802 (1994.03.12)

Accordingly, the present invention was conceived to solve the above problem, and the technical problem to be solved in the present invention is that the motor is locked due to its own factors or external factors when driving the rear wheel steering device of the vehicle. An object of the present invention is to provide a method of determining whether or not there is a failure in the case, notifying the driver, and controlling to return to a normal state.

A motor lock determination and recovery method of a rear wheel steering apparatus according to the present invention for solving the above technical problem includes the steps of: (a) determining whether the current consumption of the motor is greater than or equal to a set value; (b) determining whether the motor is locked when the current consumption of the motor is greater than or equal to a set value; (c) when the motor is in a locked state, determining whether the locked time of the motor is greater than or equal to a set time; and characterized in that it comprises.

Here, in step (a), a set value that is a reference of the current consumption of the motor may be set in a percentage (%) unit of the maximum torque current applied to the motor.

In addition, in steps (a) to (c), the determination operation may be simultaneously performed for each of a plurality of section units divided by a specific set value that is a reference of the current consumption of the motor.

In addition, when the motor lock time in step (c) is greater than or equal to the set time, it may be determined as a fault condition of the rear wheel steering system and configured to warn the driver.

On the other hand, if the motor lock time in step (c) is longer than the set time, it is determined whether the vehicle speed is higher than the set speed, and if the vehicle speed is higher than the set speed, it notifies the driver of the fault condition of the rear wheel steering system, and the vehicle speed is the set speed. In the following cases, the rear wheel steering control may be terminated until the vehicle speed reaches a set speed or higher.

In addition, as the set value for the current consumption amount of the motor for each of the plurality of section units increases, the set time for the motor lock time may be set to be small.

According to the present invention having the above-described configuration, when the rear wheel steering system is locked due to its own factors or external factors when the vehicle rear wheel steering system is driven, it is determined whether there is a failure, and the driver is notified and returned to the normal state. By controlling to return, it is possible to prevent deterioration of the battery performance due to continuous overcurrent application, and prevent burnout of the ECU due to continuous overcurrent application and deterioration of performance due to overheating of the motor.

1 is a flow chart sequentially showing a method of determining and recovering a motor lock of a rear wheel steering apparatus according to the present invention.

In the present invention, in a vehicle to which the rear wheel steering system is applied, when the rear wheel steering motor is locked due to a factor of the rear wheel steering system itself or an external factor, a determination is made and a failure is diagnosed to notify the driver. At the same time, it provides a control method to return to the normal state.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart sequentially showing a method of determining and recovering a motor lock of a rear wheel steering apparatus according to the present invention.

Referring to FIG. 1, a method for determining and restoring a motor lock of a rear wheel steering apparatus according to the present invention includes the step of checking the ready state of the electronic control unit (ECU) and the voltage of the battery (S110), and setting the current consumption of the motor. Determining whether the value is greater than or equal to the value (S120), the step of determining whether the motor lock time is greater than or equal to the set time (S130), and if the motor lock time is greater than the set time, it is determined as a fault condition of the rear wheel steering system. It includes step S140.

Specifically, in step S110, the first step, it is determined whether the ready state of the electronic control unit (ECU) in the vehicle is completed, and also, by checking the voltage of the battery, it is determined whether the voltage of the battery is normally applied to the motor. do.

If it is confirmed from the step S110 that the electronic control unit (ECU) is ready and the voltage of the battery is normally supplied, it is then determined whether the current consumption of the motor is greater than or equal to the set value (S120).

That is, in step S120, a current value flowing through the motor is measured, and it is determined whether or not the current flowing through the motor is greater than or equal to a set value. In this case, the set value, which is a reference for comparing the current consumption of the motor, is the maximum applied to the motor. It can be calculated as a percentage (%) of torque current.

In addition, the set value that is the comparison criterion for the current consumption of the motor is a percentage (%) value for each of a plurality of sections, and the current consumption of the motor and the size of the set value are simultaneously compared and Judge.

For example, as shown in Fig. 1, it is determined whether or not the current flowing through the motor is 90%, 60%, 30%, 10% or more of the maximum torque current (S120-1, S120-2, S120-3, S120 -4) can be configured. At this time, the steps S120-1, S120-2, S120-3, and S120-4 are performed simultaneously.

Subsequently, when it is determined from step S120 that the current flowing through the motor is greater than or equal to the set value (90%, 60%, 30%, 10% of the maximum torque current), it is determined whether the motor is locked.

That is, it is determined whether or not the motor is not rotating even though current is being continuously applied from the battery to the motor.

At this time, if the motor is in a locked state in which the motor is not rotated, the motor lock time is counted from that point. If the motor is in a normal state, it is related to the determination and restoration of the motor lock of the rear wheel steering system. The control algorithm ends.

Here, determination of whether the motor is in a locked state may be implemented through a position sensor installed on the motor side.

If it is determined that the motor is locked, the lock time of the motor is counted from that point to determine whether the lock time of the motor exceeds the set time (S130).

And, in determining the locking time of the motor, the set time, which is the reference, is similar to step S120 above, by applying different set time values for each of the plurality of sections, and the locking time and setting time of the motor for each of the plurality of section units. Each value size is compared and judged simultaneously.

In this case, as the set value (percentage value of the maximum torque current) for the current consumption of the motor for each section is set higher, the set time for determining the lock time of the motor is set smaller.

For example, as shown in Figure 1, the set value for the current consumption of the motor is set to 90%, 60%, 30%, 10% of the maximum torque current, the locking time of the motor for each section is 3 seconds, 7 seconds, It is determined whether it is 10 seconds or more than 15 seconds (S130-1, S130-2, S130-3, S130-4).

At this time, the steps S130-1, S130-2, S130-3, and S130-4 are performed simultaneously.

And, as a result of the determination in step S130, if it is determined that the locking time of the motor is more than the set time (3 seconds, 7 seconds, 10 seconds, 15 seconds), it is determined as a fault condition in which there is an abnormality (breakdown) in the rear wheel steering system. (S140)

When it is determined that there is an error in the operation of the rear wheel steering system as described above, the failure situation may be recognized to the driver in various forms such as a warning sound, a warning light, and a warning message, so that the driver may take follow-up measures.

Conversely, if it is determined that the locking time of the motor is less than the set time (3 seconds, 7 seconds, 10 seconds, 15 seconds) in step S130, the process of steps S120 and S130 is repeatedly performed by returning to step S110. do.

Meanwhile, the error determination of the rear wheel steering apparatus according to the above-described steps S110 to S140 is that the vehicle does not consider the speed at all.

In the rear wheel steering system, the motor lock may occur in various situations, such as a vehicle external factor or a vehicle's own factor. For example, when the vehicle is stopped, the wheel is restrained by an external structure or The motor may be locked due to external factors such as the wheel being constrained by the frictional force with the road surface, or the lead screw may excessively proceed to either side of the rear wheel steering system, causing a jamming phenomenon on one side, or The motor may be locked due to the vehicle's own factors in which foreign substances or the like are trapped in the rear wheel steering system.

Therefore, in order to reflect all the above situations, it is necessary to determine the lock of the motor reflecting the driving speed of the vehicle.

If the failure determination of the rear wheel steering system occurs below the vehicle speed (e.g., 3 km/h) at the time the rear wheel steering is started, it can be considered that the motor is locked while the vehicle is stopped. have.

That is, when the vehicle is stopped, the motor may be locked by an external factor or a vehicle's own factor.In particular, this situation is caused by the friction between the tire and the road surface while the vehicle is stopped among various locking factors. This is the case in a large situation where driving is impossible due to excessive.

At this time, if such a situation persists while the vehicle is stopped, the electronic control unit (ECU) will continuously apply a large current to the motor in the steering device, so excessive current flows and the electronic control unit (ECU) is damaged due to overheating. This will negatively affect the energy efficiency of the vehicle as a whole.

In the present invention, in consideration of such a special situation, the motor is locked in consideration of the vehicle speed.

That is, as shown in FIG. 1, after it is determined as a fault condition of the rear wheel steering apparatus due to the lock of the motor (S140), the vehicle speed at the current time is detected and the vehicle speed is set to the set speed (the speed at which the rear wheel steering is started, for example, , 3km/h) or more is determined (S160).

At this time, if it is determined that the vehicle speed is higher than the set speed (3 km/h), a warning message is sent to the driver to notify the failure of the rear wheel steering system (S170), and the vehicle speed is set to the set speed (3 km/h). If it is determined as follows, the current supply to the motor is cut off and the control of the rear wheel steering device is terminated (S180) until the vehicle speed becomes higher than the set speed at which the rear wheel steering is started, thereby preventing excessive current consumption. .

Here, when the vehicle speed is higher than a certain speed (3 km/h) and a fault condition of the rear wheel steering device occurs, the motor is locked while the vehicle is running. In this case, foreign matter in the middle part of the rear wheel steering device There is a high possibility that the motor is locked due to a pinch or external factors.

Since this is a part that requires maintenance of the rear wheel steering system, a separate warning message is displayed to the driver to inform the driver that maintenance of the rear wheel steering system is necessary.

In this case, the warning message may be applied in various forms such as a warning sound or a warning light.

When the control method of the present invention as described above is used, when the locked state of the rear wheel steering system is maintained due to the vehicle's own or external factors, it is quickly determined whether there is a failure and notified to the driver and returns to the normal state at the same time. Can be controlled to do.

Accordingly, it is possible to prevent the performance of the battery from deteriorating due to the continuous application of overcurrent to the rear wheel steering motor, and it is possible to prevent burnout of the ECU due to continuous overcurrent application and deterioration of performance due to overheating of the motor.

In the above, preferred embodiments of the present invention have been described, but the scope of the present invention is not limited to such specific embodiments, and those of ordinary skill in the relevant field may appropriately change within the scope described within the scope of the claims of the present invention. This will be possible.

S110: Determine whether the ECU is ready and the battery voltage is normal
S120: Determine whether the current consumption of the motor is more than the set value
S130: Determine whether the motor lock time is longer than the set time
S140: Steering device failure determination
S150: Determine whether the steering system is broken
S160: Determine whether the vehicle speed is higher than the set speed
S170: Alert the driver with a warning message

Claims (6)

(a) determining whether the current consumption of the motor is greater than or equal to a set value;
(b) determining whether the motor is locked when the current consumption of the motor is greater than or equal to a set value;
(c) when the motor is in a locked state, determining whether the locked time of the motor is greater than or equal to a set time;
Including,
In the steps (a) to (c), the determination operation is performed simultaneously for each of a plurality of section units divided by a specific set value that is a criterion of the current consumption of the motor. .
The method of claim 1,
A method for determining and restoring a motor lockout of a rear wheel steering apparatus, characterized in that the set value serving as a reference for the current consumption of the motor in step (a) is set in a percentage (%) unit of the maximum torque current applied to the motor.
delete The method of claim 1,
When the motor lock time in step (c) is greater than or equal to the set time, it is determined as a failure condition of the rear wheel steering system and a warning is given to the driver.
The method of claim 1,
If the motor lock time in step (c) is longer than the set time, it is determined whether the vehicle speed is higher than the set speed, and if the vehicle speed is higher than the set speed, the driver is notified of a fault condition of the rear wheel steering system, and if the vehicle speed is less than the set speed In the method of determining and restoring a motor lock of a rear wheel steering apparatus, the rear wheel steering control is terminated until the vehicle speed becomes equal to or higher than the set speed.
The method of claim 1,
The motor lock determination and recovery method of a rear wheel steering apparatus, characterized in that as the set value for the current consumption of the motor for each section is larger, the set time for the motor lock time is set to be smaller.

Images