KR102486998B1 - Apparatus and Method for Compensation Torque Steer of Vehicle with Electric Power Steering System - Google Patents

Abstract

The present invention relates to an apparatus and method for compensating for torque steer of an electric power steering system, wherein the apparatus for compensating torque steer of an electric power steering system provides vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed An information collection unit that collects at least one of information, a rapid acceleration determination unit that determines whether the vehicle is in a rapid acceleration state based on the collected information, and based on the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs A vehicle modeling unit generating a vehicle motion model and extracting a reference yaw rate, a torque compensating unit calculating a compensation torque based on the extracted reference yaw rate and a current yaw rate of the vehicle, and output control of the calculated compensation torque. A torque output unit for outputting a signal is included.

Description

Apparatus and Method for Compensation Torque Steer of Vehicle with Electric Power Steering System}

The present invention relates to an apparatus and method for compensating for torque steer in an electric power steering system, and more particularly, to an apparatus and method for compensating for a steering force lost due to a torque steer phenomenon caused by rapid acceleration of a vehicle.

The torque steer phenomenon that occurs when a vehicle accelerates rapidly is a phenomenon caused by a difference in cut angle of a drive shaft as the left and right sides do not have the same structure due to the asymmetrical arrangement of the engine and transmission.

In other words, as the left-right asymmetry of the drive shaft and the difference in the length of the incisal angle occur due to the interaction between the drive line, which is the vehicle's power transmission device, and the suspension, a force that is concentrated on the rapidly accelerating vehicle is generated, which causes steering Since the rack of the system is moved, a torque steer phenomenon in which the steering wheel turns occurs.

In addition, the causes of the torque steer phenomenon are the moment of inertia of the engine, the difference between the left and right lengths of the drive shaft, and the difference in stiffness, so the causes are very complex and diverse.

In particular, in the case of instantaneously high output, such as a high-output vehicle or a turbo, a torque steer phenomenon occurs conspicuously and deteriorates performance.

Conventional technology for reducing torque steer identifies the change and cause of the torque steer phenomenon by changing influencing factors such as engine mount change and drive shaft change, and changes the nose-up characteristics of the suspension There are technologies such as changing the hard-point and engine mount, minimizing the effect of the engine moment of inertia, and changing the turbo operation timing to minimize the instantaneous power output by the turbo. There is a problem that a lot of time and money is consumed to do this.

To solve the above problems, the present invention provides an apparatus and method for compensating torque steer by controlling steering based on driving information of a vehicle.

In addition, an apparatus and method for compensating torque steer of a vehicle by calculating compensation torque corresponding thereto based on the yaw rate are provided.

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

An apparatus for compensating for torque steer of an electric power steering system according to an embodiment of the present invention for achieving the above object includes at least one of vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed information. An information collection unit that collects one or more, a rapid acceleration determination unit that determines whether the vehicle is in a rapid acceleration state based on the collected information, and a vehicle movement based on the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs. A vehicle modeling unit that generates a model and extracts a reference yaw rate, a torque compensator that calculates a compensation torque based on the extracted reference yaw rate and the current yaw rate of the vehicle, and an output control signal of the calculated compensation torque. It may include a torque output unit that does.

In addition, a torque steer compensation method of an electric power steering system according to an embodiment of the present invention for achieving the above object includes vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed information. An information collection step of collecting at least one information, a rapid acceleration determination step of determining whether the vehicle is in a rapid acceleration state based on the collected information, a vehicle based on the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs. A vehicle modeling step of generating a motion model and extracting a reference yaw rate, a torque compensation step of calculating compensation torque for compensating the current yaw rate of the vehicle based on the extracted reference yaw rate, and output control of the calculated compensation torque A torque output step of outputting a signal may be included.

Other specific details of the invention are included in the detailed description and drawings.

As described above, the apparatus and method for compensating for torque steer of an electric power steering system according to the present invention can improve driving stability by quickly compensating for torque steer generated during rapid acceleration of a vehicle.

In addition, according to the present invention, when compensating for torque steer, it is possible to minimize a feeling of heterogeneity in steering feeling of a steering wheel.

1 is a block diagram of a torque steer compensation device of an electric power steering system according to an embodiment of the present invention.
2 is a diagram showing a data flow for a torque steer compensation device of an electric power steering system according to an embodiment of the present invention.
3 is a flowchart illustrating a torque steer compensation method of an electric power steering system according to an embodiment of the present invention.
4 is a detailed flowchart illustrating a torque steer compensation method of an electric power steering system according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods of achieving them, will become clear with reference to the detailed description of the following embodiments taken in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, only these embodiments make the disclosure of the present invention complete, and common knowledge in the art to which the present invention belongs. It is provided to fully inform the holder of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numbers designate like elements throughout the specification.

Although first, second, etc. are used to describe various elements, components and/or sections, it is needless to say that these elements, components and/or sections are not limited by these terms. These terms are only used to distinguish one element, component or section from another element, component or section. Accordingly, it goes without saying that the first element, first element, or first section referred to below may also be a second element, second element, or second section within the spirit of the present invention.

Terminology used herein is for describing the embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms unless specifically stated otherwise in a phrase. As used in the specification, a referenced component, step, operation and/or element to "comprises" and/or "made of" refers to one or more other components, steps, operations and/or elements. Existence or additions are not excluded.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a block diagram of a torque steer compensation device 100 of an electric power steering system according to an embodiment of the present invention, and FIG. 2 is a torque steer compensation device of an electric power steering system according to an embodiment of the present invention. It is a diagram showing the data flow for (100).

Referring to FIG. 1 , an apparatus 100 for compensating for torque steer of an electric power steering system according to the present invention includes at least one of vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed information. The information collection unit 110 for collecting, the sudden acceleration determination unit 120 for determining whether the vehicle is in a rapid acceleration state based on the collected information, the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs A vehicle modeling unit 130 that extracts a reference yaw rate by generating a vehicle motion model based on the vehicle motion model, a torque compensator 140 that calculates a compensation torque based on the extracted reference yaw rate and the current yaw rate of the vehicle, and calculation It may include a torque output unit 150 for outputting an output control signal of the compensated torque.

Specifically, referring to FIG. 2 , the information collection unit 110 may collect the steering information from a steering angle sensor that detects the steering angle of the steering wheel and a torque sensor that detects the steering torque of the steering wheel, and the steering information from the yaw rate sensor. Yaw rate information may be collected, and engine information may be collected from various sensors provided in the engine for detecting engine rotation speed and engine torque.

In addition, the information collection unit 110 may collect accelerator pedal position information from an accelerator pedal position sensor, and may collect the vehicle speed information from a vehicle speed sensor or a wheel speed sensor that detects rotational speeds of front or rear wheels of the vehicle.

Accordingly, the information collection unit 110 includes the Internet, Integrated Services Digital Network (ISDN), Asymmetric Digital Subscriber Line (ADSL), Local Area Network (LAN), Ethernet, Controller Area Network (CAN), TCP/IP-based communication network, The above-described information may be collected through a wireless communication network including a mobile communication network such as an optical communication network, CDMA, and WCDMA, and a local area network such as Zigbee and Bluetooth.

Further, the rapid acceleration determination unit 120 determines whether the vehicle is in a rapid acceleration state based on the information collected by the information collection unit 110, and the determination conditions are shown in Table 1 below.

Item Rapid Acceleration Judgment Condition release condition vehicle speed (kph) > 40 < 40 Engine rotation speed (RPM) ≥ 3000 < 3000 Engine torque × drive transmission ratio (%) ≥ 20 < 20 Accelerator pedal position (%) > 90 < 90 Yaw rate (deg/s) ≥ 0.25 - Steering angle (deg.) ≤ 5 > 6 Steering Torque (Nm) ≤ 0.5 > 1

Referring to Table 1, whether the vehicle speed of the vehicle is 40 kph or more, the engine rotation speed is 3000 rpm or more, the product of engine torque and drive transmission ratio is 20% or more, the accelerator pedal position is 90% or more, and the yaw rate is It is possible to determine whether the vehicle is in a rapid acceleration state by determining whether the speed is 0.25 deg/s or more, the steering angle is 5° or less, and the steering torque is 0.5 Nm or less.

At this time, the drive transmission ratio means a rotation speed ratio of the output shaft to the input shaft in the transmission.

However, it is not necessary to satisfy all of the conditions for determining the rapid acceleration state described in Table 1, and the conditions may vary depending on the type of vehicle.

Further, the vehicle modeling unit 130 may generate a 2DOF vehicle motion model that calculates the reference yaw rate corresponding to the steering angle based on the steering information and the yaw rate information collected by the information collection unit 110. there is. That is, the 2DOF vehicle motion model may match the yaw rate according to the steering angle and calculate the reference yaw rate according to the current motion state of the vehicle. However, the vehicle motion model is not limited to the aforementioned 2DOF vehicle motion model.

In addition, the vehicle modeling unit 130 may calculate the reference yaw rate by smoothing a yaw rate change amount for a predetermined time when the rapid acceleration of the vehicle occurs. That is, when the vehicle rapidly accelerates, it is difficult to calculate the reference yaw rate because the yaw rate information collected by the information collection unit 110 has a large change over time. Therefore, in order to easily calculate the reference yaw rate, an operation of smoothing the variation of the yaw rate is performed.

Further, the torque compensator 140 calculates a difference value between the current yaw rate of the vehicle collected by the information collection unit 110 and the reference yaw rate received by the vehicle modeling unit 130, and calculates a value corresponding to the difference value. The compensation torque may be calculated.

At this time, the torque compensator 140 may calculate the compensation torque by applying a PID control (Proportional Integral Derivative Control) algorithm. The compensation torque for the difference value may be calculated with a feedback control algorithm that

The torque output unit 150 may compensate for lost steering force by outputting the output control signal according to the compensation torque received from the torque compensator 140 to the steering auxiliary motor.

That is, the torque output unit 150 outputs a control signal outputting a current corresponding to the compensation torque generated by the torque steer phenomenon to the steering assist motor, thereby minimizing the effect of the torque steer phenomenon on the vehicle. there is.

In addition, the torque output unit 150 may receive or calculate steering torque for steering assist power based on the current steering information of the vehicle, add it to the compensation torque, and output the control signal.

As described above, since the torque steer compensation device 100 of the electric power steering system according to the present invention compensates for the compensation torque by performing feedback control based on the yaw rate for the steering angle, reliability can be improved.

In addition, since it is possible to provide fast compensating torque, driving stability can be improved by immediately restoring the steering wheel drift caused by the torque steer phenomenon.

3 is a flowchart illustrating a torque steer compensation method of an electric power steering system according to an embodiment of the present invention.

A torque steer compensation method of an electric power steering system according to the present invention includes an information collection step (S300) of collecting at least one of vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed information. , a rapid acceleration determination step of determining whether the vehicle is in a rapid acceleration state based on the collected information (S310), a vehicle motion model is created based on the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs, and A vehicle modeling step of extracting a yaw rate (S320), a torque compensation step of calculating a compensation torque for compensating the current yaw rate of the vehicle based on the extracted reference yaw rate (S330), and output control of the calculated compensation torque A torque output step (S340) of outputting a signal may be included.

4 is a detailed flowchart illustrating a torque steer compensation method of an electric power steering system according to an embodiment of the present invention.

Referring to FIG. 4 , engine information is collected from various sensors provided in the engine for detecting engine speed and engine torque of a vehicle, accelerator pedal position information is collected from an accelerator pedal position sensor, and a vehicle speed sensor or front wheel or Vehicle speed information is collected from the wheel speed sensor that detects the rotational speed of the rear wheels (S400).

At the same time, steering information is collected from the vehicle's steering angle sensor and torque sensor, and yaw rate information is collected from the yaw rate sensor (S410).

Then, it is determined whether the vehicle is in a rapid acceleration state based on the rapid acceleration state determination condition described in Table 1 using the above-described collected information (S420).

If the vehicle is not in a rapid acceleration state, a control signal for not outputting a current corresponding to the compensation torque is generated or a control signal for outputting only steering torque for steering assist power based on current steering information of the vehicle is generated, (S480), it is transmitted to the steering assist motor.

On the other hand, if the vehicle is in a rapid acceleration state, a 2DOF vehicle motion model for calculating a reference yaw rate corresponding to a steering angle is generated based on the collected steering information and the yaw rate information (S430).

In addition, the reference yaw rate is calculated by smoothing the yaw rate change amount for a predetermined time when the rapid acceleration of the vehicle occurs (S440).

Then, a difference value between the collected current yaw rate of the vehicle and the reference yaw rate is calculated (S460), and a compensation torque is calculated by applying the difference value to a PID control algorithm (S470).

Then, an output control signal of a current corresponding to the compensation torque is generated (S480) and outputted to the steering assist motor to compensate for lost steering force (S490).

That is, by compensating for the lost steering force to the vehicle, it is possible to easily compensate for the steering wheel drift caused by the torque steer phenomenon during rapid acceleration of the vehicle.

As described above, the apparatus and method for compensating for torque steer of an electric power steering system according to the present invention can improve driving stability by quickly compensating for torque steer generated during rapid acceleration of a vehicle. In addition, according to the present invention, when compensating for torque steer, it is possible to minimize a feeling of heterogeneity in steering feeling of a steering wheel.

The above description is merely an example of the technical idea of the present invention, and various modifications and variations can be made to those skilled in the art without departing from the essential characteristics of the present invention. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

100: torque steer compensation device
110: information collection unit 120: rapid acceleration determination unit
130: vehicle modeling unit 140: torque compensation unit
150: torque output unit

Claims (10)

an information collection unit that collects at least one of vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed information;
A rapid acceleration determination unit determining whether the vehicle is in a rapid acceleration state based on the collected information;
a vehicle modeling unit that extracts a reference yaw rate by generating a vehicle motion model based on the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs;
a torque compensator calculating compensation torque based on the extracted reference yaw rate and the current yaw rate of the vehicle; and
A torque output unit configured to output an output control signal of the calculated compensation torque;
The vehicle modeling unit,
A torque steer compensation device for calculating the reference yaw rate by smoothing a yaw rate change amount for a predetermined time when the vehicle rapidly accelerates. According to claim 1,
The vehicle modeling unit,
A torque steer compensator for generating a two-degree-of-freedom vehicle motion model for calculating the reference yaw rate corresponding to a steering angle. delete According to claim 1,
The torque compensator,
A torque steer compensator for calculating the compensation torque corresponding to a difference between the current yaw rate and the reference yaw rate. According to claim 1,
The torque compensator,
A torque steer compensation device for calculating the compensation torque by applying a PID control (Proportional Integral Derivative Control) algorithm. According to claim 1,
The torque output unit,
A torque steer compensator for compensating for lost steering force by outputting the output control signal to a steering auxiliary motor. an information collection step of collecting at least one of vehicle steering information, yaw rate information, engine information, accelerator pedal position information, and vehicle speed information;
A rapid acceleration determination step of determining whether the vehicle is in a rapid acceleration state based on the collected information;
a vehicle modeling step of extracting a reference yaw rate by generating a vehicle motion model based on the steering information and the yaw rate information collected when rapid acceleration of the vehicle occurs;
a torque compensation step of calculating compensation torque for compensating for a current yaw rate of the vehicle based on the extracted reference yaw rate; and
And a torque output step of outputting an output control signal of the calculated compensation torque;
The vehicle modeling step,
The torque steer compensation method of calculating the reference yaw rate by smoothing a yaw rate change amount for a predetermined time when the vehicle rapidly accelerates. According to claim 7,
The vehicle modeling step,
A torque steer compensation method of generating a two-degree-of-freedom vehicle motion model by calculating the reference yaw rate corresponding to a steering angle. delete According to claim 7,
The torque compensation step,
A torque steer compensation method for calculating the compensation torque by applying a PID control (Proportional Integral Derivative Control) algorithm.

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