KR20210076371A - Control Method of Torque Signals for Electric Steer - Google Patents

Abstract

The present invention relates to a method for controlling a torque signal of a motor driven power steering system (MDPS). The method for controlling the torque signal of the MDPS comprises: a first step of detecting a change amount of torque sensor 1 and torque sensor 2; a second step of calculating the sum of the change amounts detected in the first step; a third step of calculating whether the sum of the detected change amounts calculated in the second step and the sum of torque sensor outputs are within an allowable range; a fourth step of, if a corresponding sum is within the allowable range in the third step, using the output of the torque sensor 1; and a fifth step of, if a corresponding sum is out of the allowance range in the fourth step, determining whether the vehicle is currently driven or stopped, wherein, if the vehicle is being driven, it is determined whether the output value of the torque sensor 1 and the torque sensor 2 is within the allowance range to selectively use the output of the torque sensor 1 or the output of the torque sensor 2, or if the output and the change amount of the torque sensor 1 and the torque sensor 2 are out of the allowance range, the steering motor is controlled to turn off and if the vehicle is stopped, the steering motor is controlled to turn off.

Description

Control Method of Torque Signals for Electric Steer

The present invention relates to a method for controlling a torque signal of an electric steering system (MDPS), and more particularly, to a method for controlling a torque signal of an electric steering system that can resolve a driver's sense of difference in steering by responding to an immediate signal according to the occurrence of a sensor error. it's about

As a power-assisted steering system for reducing the driver's steering force when steering a vehicle, a hydraulic power steering system that assists steering force by forming hydraulic pressure in a hydraulic pump, and driving torque of an electric motor A motor driven power steering system (hereinafter referred to as 'MDPS') that assists the steering force using

Among them, the MDPS provides improved steering performance and steering feel compared to hydraulic steering systems because the electric motor is automatically controlled according to the driving conditions of the vehicle and performs a steering force assistance function according to the driver's steering wheel operation.

MDPS, which can change steering force according to driving conditions, is widely used in recently released vehicles. MDPS reduces the operating force of the steering wheel according to the vehicle speed to enable light and rapid steering operation. For this purpose, the basic configuration is a steering angle sensor, torque sensor, vehicle speed sensor, wheel speed sensor, engine speed sensor, yaw rate sensor, etc. It includes a controller (ECU) and an electric motor, and when the controller controls the driving of the electric motor, steering information (steering angle, steering wheel torque, etc.) and vehicle driving information (vehicle speed, wheel speed, engine speed) are obtained from the above sensors. , yaw rate information, etc.).

At this time, the controller calculates a current value corresponding to the torque value determined based on the steering information and the driving information as tuned and supplies it to the electric motor, and a force to assist the driver's steering force through rotation and rotation deceleration of the electric motor causes

In addition, looking at the mechanical configuration of the MDPS, a worm wheel integrally coupled to a steering shaft to which a steering wheel is coupled, a worm shaft coupled to the worm wheel, and one end of the worm shaft It includes an electric motor (hereinafter referred to as 'MDPS motor') that drives under the control of a controller (hereinafter referred to as 'MDPS controller') while connected to an electric motor (hereinafter referred to as 'MDPS motor') for transmitting power to the worm shaft, and the MDPS motor and the worm shaft connected thereto are steered The worm wheel of the shaft is rotated to assist the steering force.

This configuration is a column-driven configuration (C-MDPS) in which an MDPS motor is coupled to the steering shaft, and recently a rack-driven configuration (R-MDPS, Rack assisst Motor Driven Power Steering) in which an MDPS motor is coupled to a rack gear. This is widely applied.

The torque signal safety algorithm of the electric steering system, which is currently commercialized, periodically detects two torque sensor signals and applies an algorithm that checks whether the output range of each sensor is within the allowable value.

The two torque sensor outputs are averaged and used as the controller torque input, and in case of an error, the controller input torque is cut in half or the motor output is cut off.

The conventionally used torque sensor safety algorithm consisted of an algorithm that monitors the output of two torque sensors every cycle and checks whether the output range is within the allowable range. Even if the cable of torque sensor 1 or torque sensor 2 is short-circuited or the output value changes instantaneously due to external factors, if the sensor output value is within the normal output range, it is transmitted to the torque input of the controller and the steering wheel moves in a direction that the driver does not want. Assist may occur.

In addition, since the conventional method uses the average value of torque sensor 1 and torque sensor 2 as input to the controller, when sensor 1 or sensor 2 detects an error, the torque input to the controller is reduced by half, so the driver feels a sense of heterogeneity in the steering feeling. There is a problem that arises.

KR 10-1655678 KR 10-1405810 KR 10-1316838 KR 10-1734720 KR 10-1766074

The present invention for solving the above problems is to provide a steering torque signal control method capable of steering feeling without the user's steering sense of difference by applying an algorithm for additionally calculating a sensor output value and a periodic signal value for controlling an electric steering system. there is a purpose to

The present invention for achieving the above object, in the torque signal control method of an electric steering system, a first step of detecting the amount of change of the torque sensor 1 and the torque sensor 2, calculating the sum of the amount of change detected in the first step In the second step of calculating whether the sum of the amount of change detected in the second step and the sum of the torque sensor output is within the allowable range, the third step, and in the third step, if the sum is within the allowable range, the torque sensor 1 a fourth step of using the output of; and, when the corresponding sum in the fourth step is outside the allowable range, further comprising a fifth step of determining whether the vehicle is currently driving or stopped, In the driving state, it is determined whether the output values of the torque sensor 1 and the torque sensor 2 are within the allowable range, and the output of the torque sensor 1 or the output of the torque sensor 2 is selectively used, or the output and the amount of change of the torque sensor 1 and the torque sensor 2 If out of this allowable range, the steering motor is output as OFF, and when the vehicle is stopped, the steering motor is controlled to be output as OFF.

In addition, the allowable range of the output values of the torque sensor 1 and the torque sensor 2 is characterized in that it corresponds to the range of the maximum torque variation that the driver can produce during steering.

In addition, after the fifth step, when the vehicle is in a driving state, a sixth step of detecting whether the output value and the change amount value of the torque sensor 1 are within an allowable range is included, and if it is within the allowable range, the torque sensor 1 use the output of

In addition, after detecting whether the output value and the change amount value of the torque sensor 1 are within the allowable range, if out of the allowable range, a seventh step of detecting whether the output value and the change amount value of the torque sensor 2 are within the allowable range; , If it is within the allowable range, the output of torque sensor 2 is used.

In addition, it is characterized in that after detecting whether the output value and the change value of the torque sensor 2 are within the allowable range, the torque sensor 1 and 2 are recognized as an error value and the torque output and the motor output are turned off when out of the allowable range.

If the amount of change in the current sensor output value configured and operated as described above and the sensor output value in the previous cycle is outside the allowable range, it detects and controls it as an error, and when an error in the corresponding sensor occurs, the output value is controlled through another torque sensor, so that the steering system There is an advantage of efficiently controlling the torque signal of

That is, the present invention has the advantage that steering feeling without a sense of heterogeneity is possible by responding through other signals even when an error occurs in the sensor.

1 is a control flowchart of a torque signal control method of an electric power steering system (MDPS) according to the present invention.

Hereinafter, a method of controlling a torque signal of an electric power steering system (MDPS) according to the present invention will be described in detail with reference to the accompanying drawings.

In the method for controlling a torque signal of an electric power steering system (MDPS) according to the present invention, in the method for controlling a torque signal of an electric power steering system, a first step of detecting a change amount of a torque sensor 1 and a torque sensor 2 is detected in the first step The second step of calculating the sum of the change amount detected in the second step, the third step of calculating whether the sum of the amount of change detected in the second step and the sum of the torque sensor output is within the allowable range, and in the third step, the corresponding sum is within the allowable range A fourth step of using the output of the torque sensor 1 in the case of ; and, if the sum is out of the allowable range in the fourth step, a fifth step of determining whether the vehicle is currently running or stopped is further performed Including, when the vehicle is in a driving state, it is determined whether the output values of the torque sensor 1 and the torque sensor 2 are within an allowable range to selectively use the output of the torque sensor 1 or the output of the torque sensor 2, or the torque sensor 1 and the torque sensor When the output of 2 and the amount of change are out of the allowable range, the steering motor is output as OFF, and when the vehicle is stopped, it is controlled to output the steering motor as OFF.

The present invention is to control the electric motor by outputting another torque sensor signal when an error occurs in the sensor output of the torque sensor 1 and the torque sensor 2 in controlling the electric steering system, thereby providing the driver's steering force without a sense of heterogeneity. There is a purpose.

To this end, the present invention provides an error detection algorithm for torque sensor input and a safety algorithm for torque signal to a vehicle in which the MDPS is mounted.

1 is a control flowchart of a method for controlling a torque signal of an electric power steering system (MDPS) according to the present invention.

The torque signal control method according to the present invention is largely composed of first to seventh steps. As shown, the amount of change of the torque sensor 1 and the torque sensor 2 is first detected in order to control the steering device torque signal. Here, the change amount corresponds to a value obtained by subtracting the output value of the previous torque sensor from the output of the current torque sensor. A first step (S100) of detecting changes in each of the torque sensor 1 and the torque sensor 2 is performed.

Next, the second step of calculating the sum of the torque sensor 1 and the torque sensor 2 (S200). The allowable output range of the torque sensor corresponds to the output range indicated in the torque sensor data sheet, and torque sensor 1 and torque sensor 2 have an inverse relationship with each other, and in normal operation, the sum of the two outputs is constant.

A third step (S300) of detecting whether the torque sensor sum and the torque sensor change amount detected in the first step (S100) and the second step (S200) is within an allowable range is performed. At this time, the allowable range of the torque sensor variation corresponds to the maximum torque variation range that the driver can momentarily make during sudden steering.

If it is determined in the third step (S300) to be within the allowable range, the torque sensor 1 and the torque sensor 2 are determined as normal outputs, and the motor of the steering device is controlled using the output of the torque sensor 1 (S500), out of the allowable range. In this case, a fifth step (S500) of determining whether the vehicle is driven is performed.

In the fifth step, it is preferably determined whether the vehicle is stopped or driven based on the driving speed of 3 km, but this is only an example, and the reference speed value may vary depending on the characteristics of the steering system.

When it is determined that the vehicle is stopped through the fifth step (S500), the torque output becomes zero and the control is terminated by turning off the motor output.

On the other hand, when it is determined that the vehicle is driving in the fifth step (S500), a sixth step (S600) of determining whether the output allowable range of the torque sensor 1 and the change amount is within the allowable range is performed. If it is within the allowable range, the output of torque sensor 2 is judged as an error, and the output of torque sensor 1 is commanded to be used.

If it is out of the allowable range, it is determined whether the output allowable range and the amount of change of torque sensor 2 are within the allowable range. If it is within the allowable range, the signal from torque sensor 1 is judged as an error, and the output of torque sensor 2 is used. A seventh step (S700) is performed.

If it is out of the allowable range in the seventh step, it is finally determined as an error of the torque sensor 1 and the torque sensor 2, the torque output is set to zero and the motor output is turned OFF, thereby ending the control operation.

As described above, the present invention detects and controls an error when the amount of change between the current sensor output value and the sensor output value in the previous cycle is outside the allowable range, and when an error occurs in the corresponding sensor, the output value is controlled through another torque sensor. There is an advantage of efficiently controlling the torque signal of

The present invention configured as described above compares the output signal of the previous torque sensor with the output signal of the current torque sensor to determine whether the amount of change is in a false range, determines whether there is an error, and controls the torque input of the controller through this. There is an effect of controlling the motor output of the steering system to provide a steering feeling without any sense of alienation to the driver.

Although the foregoing has been described and illustrated in connection with preferred embodiments for illustrating the principles of the present invention, the present invention is not limited to the construction and operation as so shown and described. Rather, it will be apparent to those skilled in the art that many changes and modifications can be made to the present invention without departing from the spirit and scope of the appended claims. Accordingly, all such suitable alterations and modifications and equivalents are to be considered as being within the scope of the present invention.

S100: Step 1
S200: 2nd step
S300: Step 3
S400: Step 4
S500: Step 5
S600: Step 6
S700: Step 7

Claims (5)

A method for controlling a torque signal of an electric steering device,
A first step of detecting the amount of change of the torque sensor 1 and the torque sensor 2;
a second step of calculating a sum of the amount of change detected in the first step;
a third step of calculating whether the sum of the amount of change detected in the second step and the sum of the torque sensor output is within an allowable range; and
and a fourth step of using the output of the torque sensor 1 when the corresponding sum in the third step is within the allowable range;
In the fourth step, if the corresponding sum is out of the allowable range, a fifth step of determining whether the vehicle is currently driving or stopped; further comprising,
When the vehicle is in a driving state, it is determined whether the output values of the torque sensor 1 and the torque sensor 2 are within an allowable range, and the output of the torque sensor 1 or the output of the torque sensor 2 is selectively used, or the output of the torque sensor 1 and the torque sensor 2 If the over-change amount is out of the allowable range, the steering motor is output as OFF,
A torque signal control method of an electric steering system (MDPS) that controls to output the steering motor to OFF when the vehicle is stopped. According to claim 1, wherein the allowable range of the output values of the torque sensor 1 and the torque sensor 2,
A method of controlling a torque signal of an electric steering system (MDPS), characterized in that it corresponds to the range of the maximum torque change that a driver can produce during steering. According to claim 1, After the fifth step,
When the vehicle is in a driving state, including a sixth step of detecting whether the output value and the change amount value of the torque sensor 1 are within an allowable range, an electric steering device using the output of the torque sensor 1 if it is within the allowable range ( MDPS) torque signal control method. 4. The method of claim 3,
a seventh step of detecting whether the output value and change value of the torque sensor 1 are within the allowable range after detecting whether the output value and the change amount value are within the allowable range, and detecting whether the output value and the change amount value of the torque sensor 2 are within the allowable range; If it is within the range, the torque signal control method of the electric steering system (MDPS) using the output of the torque sensor 2. 5. The method of claim 4,
After detecting whether the output value and variation value of the torque sensor 2 are within the allowable range, if it is out of the allowable range, the torque sensors 1 and 2 are recognized as error values and the torque output and the motor output are turned off. Torque signal control method.

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