KR20200027746A - Electric Power Steering Apparatus and Control Method for the same - Google Patents

Abstract

The present disclosure provides an electric power steering device including: a motor unit including a first motor providing force for movement of a rack and a second motor providing force for movement of the rack in synchronization with the first motor; a sensor unit including a torque angle sensor for detecting a torque value and a steering angle according to steering of a steering wheel, and an angle sensor for detecting the rotation angle of a sector shaft; and a control unit which controls the motor unit according to the steering of the steering wheel, calculates the compensation rotation amount of the motor unit based on the steering angle and the rotation angle, and controls the rotation amount of the motor unit according to the compensation rotation amount. According to the present disclosure, the rotation amount of a wheel can be adjusted so that driver′s actual steering will can be accurately reflected.

Description

Electric Power Steering Apparatus and Control Method for the same}

The present disclosure relates to an electric power steering apparatus for controlling driving of a motor unit provided in an electric power steering apparatus and a control method thereof.

In general, a steering device of a vehicle is a device for changing a vehicle's driving direction according to the driver's will, and an electric power steering device uses a booster when a driver operates a steering wheel of a vehicle. It is a device that can easily change the traveling direction of the vehicle with a smaller force by assisting the steering wheel operation force.

On the other hand, a large commercial vehicle has a vehicle body length or weight that is larger than that of a passenger car, and thus requires rigidity capable of withstanding high power and high power, and thus conventionally uses a hydraulic power steering device. However, with the introduction of various driver assistance systems in recent years, driver assistance systems and electric power steering devices have been gradually applied to large commercial vehicles.

Accordingly, there is a need for a control method capable of controlling the motor unit so that the driver's steering will is accurately reflected in connection with the control of the electric power steering device mounted in the large commercial vehicle.

Against this background, the object of the present disclosure is to control the rotation amount of the motor unit according to the amount of compensation rotation calculated by comparing the steering angle according to the steering wheel steering and the rotation angle of the sector shaft, so that the driver's actual steering will is accurately reflected. It is to provide an electric power steering device that can adjust the amount of rotation of the wheel and a control method thereof.

Another object of the present disclosure, by calculating the compensation amount of rotation of the motor according to the actual amount of rotation of the sector shaft using an angle sensor installed on the sector shaft, an electric power steering device that can more accurately adjust the amount of rotation of the wheel and its control Is to provide a way.

In order to achieve the above object, in one aspect, the present disclosure provides a motor including a first motor providing power for movement of the rack and a second motor synchronizing with the first motor to provide power for movement of the rack. The control unit includes a sensor unit including a torque angle sensor for detecting a torque value and a steering angle according to steering of the steering wheel, and an angle sensor for detecting a rotation angle of a sector shaft, and a motor unit according to the steering of the steering wheel. It provides an electric power steering apparatus including a control unit for calculating the amount of compensation rotation of the motor unit based on, and controlling the amount of rotation of the motor unit in accordance with the amount of compensation rotation.

In another aspect, the present disclosure includes controlling a motor unit according to steering of the steering wheel, detecting a torque value and steering angle according to steering of the steering wheel, detecting a rotation angle of a sector shaft, and comparing steering angle and rotation angle. It provides a control method of the electric power steering apparatus comprising the step of calculating the compensation amount of rotation of the motor unit and controlling the amount of rotation of the motor unit according to the amount of compensation rotation.

As described above, according to the present disclosure, the actual steering intention of the driver is accurately reflected by controlling the amount of rotation of the motor according to the amount of compensation calculated by comparing the steering angle according to steering of the steering wheel and the rotation angle of the sector shaft. It is possible to provide an electric power steering device capable of adjusting the amount of rotation of the wheel and a control method thereof.

In addition, according to the present disclosure, by calculating the compensation amount of rotation of the motor unit according to the actual amount of rotation of the sector shaft using an angle sensor installed on the sector shaft, an electric power steering device that can more accurately adjust the amount of rotation of the wheel and its control Can provide a method.

1 is a block diagram of an electric power steering apparatus according to the present disclosure.
2 is a view for explaining the operation of the electric power steering apparatus according to the present disclosure.
3 is a view for explaining the meshing structure of the worm and the worm wheel of the electric power steering apparatus according to the present disclosure.
4 to 6 are views for explaining an angle sensor installed on a sector shaft according to the present disclosure.
7 is a flowchart of a control method of an electric power steering apparatus according to the present disclosure.
8 is a flowchart for explaining a control method for adjusting the amount of rotation of the motor unit according to the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail through exemplary drawings. In adding reference numerals to the components of each drawing, the same components may have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing the present disclosure, when it is determined that a detailed description of a related known configuration or function may obscure the subject matter of the present disclosure, the detailed description may be omitted.

In addition, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected to or connected to the other component, but another component between each component It should be understood that elements may be "connected", "coupled" or "connected".

Unless otherwise defined, all terms (including technical and scientific terms) used in the present disclosure may be used as meanings commonly understood by those skilled in the art to which the embodiments of the present disclosure pertain. . In addition, terms defined in the commonly used dictionary are not ideally or excessively interpreted unless specifically defined. In addition, terms to be described later are terms defined in consideration of functions in the embodiments of the present disclosure, which may vary according to a user's or operator's intention or practice. Therefore, the definition should be made based on the contents throughout the present disclosure.

In the present disclosure, "compensation rotation amount" means the amount of rotation in which the motor unit must be rotated to compensate for the difference when the driver's intended steering amount is different from the actual vehicle's wheel rotation amount.

The present disclosure may be more effective to be applied to a large commercial vehicle on the premise of an electric power steering device having a dual motor, but is not limited thereto. The contents of the present disclosure can be applied substantially the same to a general vehicle, except when the application is impossible.

Hereinafter, an electric power steering apparatus and a control method thereof according to embodiments of the present disclosure will be described with reference to the accompanying drawings.

1 is a block diagram of an electric power steering apparatus according to the present disclosure.

Referring to Figure 1, the electric power steering apparatus 100 according to the present disclosure is synchronized with the first motor 111 and the first motor providing a force for the movement of the rack (rack), the force for the movement of the rack Motor unit 110 including a second motor 113 provided, a torque angle sensor 131 for detecting a torque value and a steering angle according to steering of the steering wheel, and an angle for detecting a rotation angle of a sector shaft The motor unit is controlled according to the steering of the sensor unit 130 including the sensor 133 and the steering wheel, and the amount of rotation of the motor unit is calculated according to the amount of compensation rotation by comparing the steering angle and the rotation angle. It includes a control unit 150 to control.

The motor unit 110 may include a first motor 111 and a second motor 113 for providing auxiliary steering force when the driver operates the steering wheel of the vehicle. The first motor 111 may provide an auxiliary steering force required when the rack is moved to a position where the vehicle is steered according to the driver's intention. When the driver operates the steering wheel, the first motor 111 may be driven under the control of the control unit in order to detect the steering angle of the steering wheel and provide an auxiliary steering force calculated based on the detected steering angle.

The second motor 113 may provide an auxiliary steering force required when moving the rack to a position that allows the vehicle to steer according to the driver's intention. When the driver operates the steering wheel, the second motor 113 may be driven under the control of the control unit in order to detect the steering angle of the steering wheel and provide an auxiliary steering force calculated based on the detected steering angle.

According to an example, the second motor 113 may be driven in synchronization with the first motor 111. The first motor 111 and the second motor 113 may output a force for rotating the same one worm wheel in the electric power steering apparatus 100, and accordingly, the first motor 111 and the first motor 111 2 The operation of the motor 113 may be performed in synchronization.

In addition, only one of the first motor 111 and the second motor 113 can be selectively driven. In addition, the first motor 111 and the second motor 113 may rotate in the same direction with each other or in different directions.

The sensor unit 130 includes a torque angle sensor (TAS, 131) that detects a torque value and a steering angle according to steering of the steering wheel, and an angle sensor (Angle Sensor, AS, 133) that detects a rotation angle of a sector shaft. It may include.

The torque angle sensor 131 may be connected to the steering shaft between the steering wheel and the first reduction unit to detect torque values and steering angles due to twisting and rotation of the steering shaft. The torque angle sensor 131 may provide the detected torque value and steering angle information to the controller 150. According to an example, the sensor unit 130 may include a steering angle sensor (SAS), which is a torque angle sensor replacement or separately provided. In this case, the steering angle detected by the steering angle sensor may be provided to the controller 150.

The angle sensor 133 is installed on the sector shaft rotated according to the sliding of the ball nut included in the second reduction unit, so that the rotation angle of the sector shaft can be detected. The angle sensor 133 may provide the detected rotation angle information to the controller 150.

The controller 150 may control the overall operation of the electric power steering apparatus 100. According to an example, the control unit 150 may be implemented as a micro control unit (MCU) or an electronic control unit (ECU). The control unit 150 may control the first motor 111 and the second motor 113 by synchronizing each other. The controller 150 may receive status information of the first motor 111 and the second motor 113 through CAN. The control unit 150 may control the current applied to the first motor 111 and the second motor 113 so that the wheel is steered according to steering of the steering wheel.

The control unit 150 may compare the steering angle detected by the torque angle sensor 111 and the amount of rotation of the wheel according to the rotation angle detected by the angle sensor 113. The controller 150 may calculate the amount of rotation of the wheel to be rotated according to the detected steering angle. The control unit 150 may calculate the amount of rotation of the wheel according to the detected rotation angle.

The control unit 150 may calculate a compensation amount of rotation of the motor unit 110 by comparing the amount of rotation of the wheel according to the detected steering angle and the amount of rotation of the wheel according to the detected rotation angle. Since the torque angle sensor 131 detects the steering angle according to the rotation of the steering shaft connected to the steering wheel, the steering angle detected by the torque angle sensor 131 may be interpreted as the rotation angle of the wheel according to the driver's steering intention. In addition, the angle sensor 133 may be installed on the sector shaft, and the sector shaft is connected to the wheel through a pitman arm, a tie rod, or the like, so that the rotation detected by the angle sensor 133 The angle can be interpreted as the actual rotation angle of the wheel.

The control unit 150 considers the steering gear through the steering wheel and each gear ratio in the route through which the auxiliary steering force provided by the motor unit 110 is transmitted, and the wheel amount according to the detected steering angle according to the detected rotation angle. Compensation rotation amount of the motor unit 110 to reach the rotation amount of the can be calculated. The control unit 150 may control the rotation amount of the motor unit 110 according to the calculated amount of compensation rotation. Accordingly, errors that may occur while passing through the first reduction unit and the second reduction unit during steering control may be compensated.

According to an example, when both the first motor 111 and the second motor 113 are being driven, the controller 150 controls the current applied to the first motor 111 and the second motor 113, The amount of rotation of the motor unit 110 may be adjusted to satisfy the calculated amount of compensation rotation. Since the first motor 111 and the second motor 113 rotate one worm wheel, according to an example, the control unit 150 may control the motor unit 110 based on the rotation amount of the worm wheel.

According to an example, when only one of the first motor 111 and the second motor 113 is being driven, the controller 150 may further apply a compensation current based on the compensation rotation amount to further rotate the driving motor. have. Alternatively, a compensation current may be applied to drive a motor that is not being driven to rotate further by the compensation rotation amount.

That is, when the rotation angle to which the sector shaft is to be rotated compared to the steering angle of the steering wheel is not satisfied, the control unit 150 controls the motor unit 110 to control the position of the sector shaft according to the calculated amount of compensation rotation (angle overlay).

According to this, the amount of rotation of the wheel can be adjusted so that the actual steering intention of the driver is accurately reflected by controlling the amount of rotation of the motor according to the amount of compensation calculated by comparing the steering angle according to the steering of the steering wheel and the rotational angle of the sector shaft. have. In addition, by calculating the compensated rotation amount of the motor unit according to the actual rotation amount of the sector shaft using the angle sensor installed in the sector shaft, it is possible to more accurately adjust the rotation amount of the wheel.

2 is a view for explaining the operation of the electric power steering apparatus according to the present disclosure. 3 is a view for explaining the meshing structure of the worm and the worm wheel of the electric power steering apparatus according to the present disclosure. 4 to 6 are views for explaining an angle sensor installed on a sector shaft according to the present disclosure.

Referring to FIG. 2, the electric power steering apparatus 100 has a force provided by the first reduction unit 160 and the first reduction unit having a power transmission structure by the engagement of the worms 161 and 162 and the worm wheel 163. A second reduction unit 170 having a power transmission structure using a ball screw 171 and a ball nut 172 may be further included to be transmitted to the rack.

When the driver steers the steering wheel 180 to steer the vehicle, the steering shaft 190 rotates, and accordingly, the torque value and the steering angle can be detected by the torque angle sensor 131. According to an example, a steering angle sensor that detects a steering angle may be used. The torque angle sensor 131 may be connected to the steering shaft 190 between the steering wheel 180 and the first reduction unit 160 to detect torque values and steering angles due to twisting and rotation of the steering shaft. The operation of the torque angle sensor 131 is according to a known method, and a detailed description will be omitted.

The first motor 111 may be coupled to the first worm 161 to rotate the first worm 161 when driving. The second motor 113 may be coupled to the second worm 162 to rotate the second worm 162 when driving. The first worm 161 and the second worm 162 may mesh with the worm wheel 163. Referring to FIG. 3, according to an example, a structure in which the first worm 161 and the second worm 162 mesh with the worm wheel 163 is illustrated. The rotation axis of the first motor 111 may be coupled coaxially with the first worm 161, and the rotation axis of the second motor 113 may be coupled coaxially with the second worm 162.

According to an example, the first motor 111 and the second motor 113 may be disposed in the same direction based on the first worm 161 and the second worm 162. That is, in FIG. 3, when the first motor 111 is coupled to the end shown to the left of the first worm 161, the second motor 113 is also attached to the end shown to the left of the second worm 162. , In parallel with the first motor 111, may be combined. According to an example, the first motor 111 and the second motor 113 are implemented as a dual motor, which is one configuration coupled in parallel so as to be coupled with the first worm 161 and the second worm 162, respectively. Can be.

For example, when the first worm 161 rotates clockwise according to the driving of the first motor 111, it is assumed that the worm wheel 163 is engaged to rotate in the forward direction. In this case, when the second worm 162 rotates counterclockwise according to the driving of the second motor 113, the worm heel 163 receives more force in the forward direction, so that a larger auxiliary steering force can be output. Conversely, when the second worm 162 is rotated in the clockwise direction, since the forces of the first motor 111 and the second motor 113 act on the worm wheel 163 opposite to each other, the auxiliary steering force may be reduced.

Similarly, when the first worm 161 rotates counterclockwise according to the driving of the first motor 111, the worm wheel 163 may be rotated in the reverse direction. In this case, when the second worm 162 rotates in the clockwise direction according to the driving of the second motor 113, the worm heel 163 receives more force in the reverse direction, so that a larger auxiliary steering force can be output. Conversely, when the second worm 162 is rotated counterclockwise, since the forces of the first motor 111 and the second motor 113 act on the worm wheel 163 opposite to each other, the auxiliary steering force for the reverse direction is reduced. Can be.

Referring to FIG. 2 again, when the worm wheel is rotated by the first motor 111 and the second motor 113, the ball screw 171 coupled thereto may be rotated. According to the rotation of the ball screw 171, the ball screw 171 and the ball nut 172 coupled via a ball may be slid. When the sector shaft 120 rotates according to the sliding of the ball nut 172, the pitman arm coupled with the sector shaft 120 is rotated, so that a force can be provided to the rack.

The controller 150 may appropriately adjust the current supplied to the first motor 111 and the second motor 113 according to the situation of the vehicle to efficiently supply auxiliary steering force in forward or reverse steering. The control unit 150 may control the driving of the motor unit 110 so that the electric power steering device 100 performs an operation for adjusting the steering force felt by the driver.

The angle sensor 133 is installed on the sector shaft 120 that rotates according to the sliding of the ball nut 172 included in the second reduction unit 170 to detect the rotation angle of the sector shaft. Referring to FIG. 4, an enlarged cross section of the second reduction unit 170 and the sector shaft 120 is illustrated. As described above, the ball screw 171 rotates according to the driving of the motor unit 110, and the ball nut 172 slides according to the rotation of the ball screw 171. As the ball nut 172 slides, the sector shaft 120 rotates left and right.

According to an example, the angle sensor 133 may be installed on one surface of the sector gear 121 formed on the outer circumference of the sector shaft 120 and engaged with the ball nut 172. Specifically, referring to FIGS. 5 and 6, the angle sensor 133 includes at least one magnet 1331 installed on one surface of the sector gear 121 and a magnetic sensor 1333 that senses magnetism by the magnet. It may include.

According to an example, the magnetic sensor 1333 may be installed opposite to the magnet 1331 on one surface of the housing 125 surrounding the sector shaft and the sector gear, as shown in FIG. 6. The magnetic sensor 1333 may sense magnetism by the magnet 1331. According to an example, the magnetic sensor 1333 may be implemented as a hall IC. However, as an example, the magnetic sensor 1333 is not limited to a specific type as long as it is a sensor capable of detecting magnetism by a magnet.

When the sector shaft 120 rotates according to the sliding of the ball nut 172, the magnet 1331 installed in the sector gear 121 is also rotated. As the magnet 1331 moves, the strength of the magnetic field of the magnet sensed by the magnetic sensor 1333 changes. The magnetic sensor 1333 may detect the rotation angle of the sector shaft 120 using the detected change in the intensity of the magnetic field.

However, the angle sensor illustrated in FIGS. 5 and 6 is an example, and is not limited thereto. The number of magnets and magnetic sensors or the installation location may be set differently according to need. In addition, if the rotation angle of the sector shaft 120 can be detected, the angle sensor may not be limited to a specific type of sensor.

The controller 150 may calculate a compensation rotation amount by comparing the rotation amount of the wheel calculated according to the steering angle and the rotation amount of the wheel calculated according to the rotation angle. The control unit 150 may compare the steering angle detected by the torque angle sensor 111 and the amount of rotation of the wheel according to the rotation angle detected by the angle sensor 113. The controller 150 may calculate the amount of rotation of the wheel to be rotated according to the detected steering angle. The control unit 150 may calculate the amount of rotation of the wheel according to the detected rotation angle.

The control unit 150 may calculate a compensation amount of rotation of the motor unit 110 by comparing the amount of rotation of the wheel according to the detected steering angle and the amount of rotation of the wheel according to the detected rotation angle. As shown in FIG. 2, the torque angle sensor 131 may detect a steering angle according to the rotation of the steering shaft 190 connected to the steering wheel 180. Since the steering angle according to the rotation of the steering wheel 180 by the driver is detected, the steering angle detected by the torque angle sensor 131 may be the rotation angle of the wheel intended by the driver.

According to the previously detected steering angle, the motor unit 110 is driven, and the auxiliary steering force provided by the motor unit 110 is reflected to rotate the sector shaft 120. As the sector shaft 120 rotates, the steering force is transmitted to the rack through a pitman arm, tie rod, or the like, and the wheel rotates according to the movement of the rack. The angle sensor 133 is installed on the sector shaft 120, and since the rotation of the sector shaft 120 is associated with the rotation of the wheel, the rotation angle detected by the angle sensor 133 may occur in the process of calculating or transmitting the auxiliary steering force. It can be the actual rotation angle of the wheel to which an error can be applied.

When calculating the compensation rotation amount, the control unit 150 may consider each gear ratio (for example, gear ratios of worms and worm wheels) in the route through which the steering force through the steering wheel and the auxiliary steering force provided by the motor unit 110 are transmitted. You can. The control unit 150 may calculate a compensated rotation amount of the motor unit 110 such that the rotation amount of the wheel according to the detected rotation angle reaches the rotation amount of the wheel according to the detected steering angle. The control unit 150 may control the rotation amount of the motor unit 110 according to the calculated amount of compensation rotation. Accordingly, errors that may occur while passing through the first reduction unit 160 and the second reduction unit 170 during steering control may be compensated.

According to an example, when both the first motor 111 and the second motor 113 are being driven, the controller 150 controls the current applied to the first motor 111 and the second motor 113, The amount of rotation of the motor unit 110 may be adjusted to satisfy the calculated amount of compensation rotation. Since the first motor 111 and the second motor 113 rotate one worm wheel, according to an example, the control unit 150 may control the motor unit 110 based on the rotation amount of the worm wheel.

According to an example, when only one of the first motor 111 and the second motor 113 is being driven, the controller 150 may further apply a compensation current based on the compensation rotation amount to further rotate the driving motor. have. Alternatively, a compensation current may be applied to drive a motor that is not being driven to rotate further by the compensation rotation amount.

That is, when the rotation angle to which the sector shaft is to be rotated compared to the steering angle of the steering wheel is not satisfied, the control unit 150 controls the motor unit 110 to control the position of the sector shaft according to the calculated amount of compensation rotation (angle overlay). According to an example, the controller 150 may perform position control using Proportional Integral Control (PI control). The auxiliary steering force provided as the motor unit 110 further rotates based on the amount of rotation can be used to control the position of the rack by further rotating the sector shaft 120 connected through the rack and the pitman arm. have.

According to this, the amount of rotation of the wheel can be adjusted so that the actual steering intention of the driver is accurately reflected by controlling the amount of rotation of the motor according to the amount of compensation calculated by comparing the steering angle according to the steering of the steering wheel and the rotational angle of the sector shaft. have. In addition, by calculating the compensated rotation amount of the motor unit according to the actual rotation amount of the sector shaft using the angle sensor installed in the sector shaft, it is possible to more accurately adjust the rotation amount of the wheel.

7 is a flowchart of a control method of an electric power steering apparatus according to the present disclosure. 8 is a flow chart for explaining a control method for adjusting the amount of rotation of the motor unit according to the present disclosure.

The control method of the electric power steering apparatus according to the present disclosure may be implemented in the electric power steering apparatus 100 described with reference to FIG. 1. Hereinafter, a control method of an electric power steering apparatus according to the present disclosure and an operation of the electric power steering apparatus 100 for realizing the same will be described in detail with reference to necessary drawings.

Referring to FIG. 7, the electric power steering apparatus may control the motor unit according to steering of the steering wheel [S110].

The motor part of the electric power steering device may include a first motor and a second motor for providing auxiliary steering force when the driver operates the steering wheel of the vehicle. The motor unit may provide auxiliary steering force required when moving the rack to a position that allows the vehicle to steer according to the driver's intention.

When the driver operates the steering wheel, the steering unit of the steering wheel is sensed, and the motor unit may be driven under the control of the control unit to provide an auxiliary steering force calculated based on the detected steering angle. The control unit of the electric power steering apparatus may control current applied to the first motor and the second motor such that the wheel is steered according to steering of the steering wheel.

Referring again to FIG. 7, the electric power steering apparatus may detect a torque value and a steering angle according to steering of the steering wheel [S120].

The sensor unit of the electric power steering apparatus may include a torque angle sensor that detects a torque value and a steering angle according to steering of the steering wheel. The torque angle sensor may be connected to the steering shaft between the steering wheel and the first reduction unit to detect torque values and steering angles due to twisting and rotation of the steering shaft. The torque angle sensor may provide the detected torque value and steering angle information to the control unit.

Again, referring to FIG. 7, it is possible to detect the rotation angle of the sector shaft [S130].

The sensor unit of the electric power steering apparatus may include an angle sensor that detects the rotation angle of the sector shaft. The angle sensor is installed on the sector shaft rotated according to the sliding of the ball nut included in the second reduction unit, so that the rotation angle of the sector shaft can be detected. The angle sensor may provide the detected rotation angle information to the control unit.

Again, referring to FIG. 7, a compensation amount of the motor unit may be calculated by comparing the steering angle and the rotation angle [S140].

The control unit of the electric power steering apparatus may compare the steering angle detected by the torque angle sensor and the amount of rotation of the wheel according to the rotation angle detected by the angle sensor. The control unit may calculate the amount of rotation of the wheel to be rotated according to the detected steering angle. The control unit may calculate the amount of rotation of the wheel according to the detected rotation angle.

The control unit may calculate a compensated rotation amount of the motor unit by comparing the rotation amount of the wheel according to the detected steering angle and the rotation amount of the wheel according to the detected rotation angle. The control unit considers each gear ratio in the route through which the steering force through the steering wheel and the auxiliary steering force provided by the motor are transmitted, so that the amount of rotation of the wheel according to the detected rotation angle reaches the amount of rotation of the wheel according to the detected steering angle. Compensation rotation amount of the motor part can be calculated.

Referring to FIG. 7 again, the electric power steering apparatus may control the amount of rotation of the motor unit according to the amount of compensation rotation [S150].

The control unit of the electric power steering apparatus may control the rotation amount of the motor unit according to the calculated amount of compensation rotation. Accordingly, errors that may occur while passing through the first reduction unit and the second reduction unit during steering control may be compensated.

According to an example, when both the first motor and the second motor are being driven, the control unit may control the current applied to the first motor and the second motor to adjust the rotation amount of the motor unit to satisfy the calculated compensation rotation amount. have. Since the first motor and the second motor rotate one worm wheel, according to an example, the control unit may control the motor unit based on the rotation amount of the worm wheel.

According to an example, when only one of the first motor and the second motor is being driven, the control unit may further apply a compensation current based on the compensation rotation amount to further rotate the driving motor. Alternatively, a compensation current may be applied to drive a motor that is not being driven to rotate further by the compensation rotation amount.

That is, when the rotation angle to which the sector shaft is to be rotated is not satisfied compared to the steering angle of the steering wheel, the control unit may control the motor unit to perform position control to further rotate the sector shaft according to the calculated amount of compensation rotation.

According to this, the amount of rotation of the wheel can be adjusted to accurately reflect the driver's actual steering will by controlling the amount of rotation of the motor according to the amount of compensation calculated by comparing the steering angle according to the steering of the steering wheel and the rotation angle of the sector shaft. have. In addition, by calculating the compensated rotation amount of the motor unit according to the actual rotation amount of the sector shaft using the angle sensor installed in the sector shaft, it is possible to more accurately adjust the rotation amount of the wheel.

Hereinafter, the calculation of the compensation rotation amount and the control of the motor unit according to the present disclosure will be described in more detail with reference to FIG. 8.

Referring to FIG. 8, when the driver steers the steering wheel [S210] and steers the vehicle, the steering shaft rotates, and accordingly, the torque angle sensor and the steering angle can be detected by the torque angle sensor [S220]. The torque angle sensor may be connected to the steering shaft between the steering wheel and the first reduction unit to detect torque values and steering angles due to twisting and rotation of the steering shaft.

The control unit may appropriately adjust the current supplied to the first motor and the second motor according to the situation of the vehicle, and rotate the motor unit when forward or reverse steering [S230]. The control unit may control the driving of the motor unit so that the electric power steering device performs an operation for adjusting the steering force felt by the driver.

The ball screw of the second reduction unit rotates according to the driving of the motor unit, and the ball nut slides according to the rotation of the ball screw. As the ball nut slides, the sector shaft rotates in a predetermined angle range [S240].

The angle sensor is installed on the sector shaft, and can detect the rotation angle of the sector shaft [S250]. As the sector shaft rotates, the steering force is transmitted to the rack through a pitman arm, tie rod, or the like connected to the sector shaft, and the wheel can rotate accordingly (S260).

According to an example, the angle sensor may be installed on one surface of the sector gear formed on the outer circumference of the sector shaft and engaged with the ball nut. The angle sensor may include at least one magnet installed on one surface of the sector gear, and a magnetic sensor that senses magnetism by the magnet.

According to an example, the magnetic sensor may be installed on one side of the housing surrounding the sector shaft and the sector gear, facing the magnet. The magnetic sensor can detect magnetism by the magnet. According to an example, the magnetic sensor may be implemented as a Hall IC. However, as an example, the magnetic sensor is not limited to a specific type as long as it is a sensor capable of detecting magnetism by a magnet.

When the sector shaft rotates according to the sliding of the ball nut, the magnet installed in the sector gear is also rotated. As the magnet moves, the magnetic field strength of the magnet sensed by the magnetic sensor changes. The magnetic sensor may detect the rotation angle of the sector shaft using the detected change in the intensity of the magnetic field.

The control unit may compare the rotation amount of the wheel calculated according to the steering angle and the rotation amount of the wheel calculated according to the rotation angle [S270]. The control unit may compare the steering angle detected by the torque angle sensor and the amount of rotation of the wheel according to the rotation angle detected by the angle sensor. The control unit may calculate the amount of rotation of the wheel to be rotated according to the detected steering angle. The control unit may calculate the amount of rotation of the wheel according to the detected rotation angle.

The control unit may calculate a compensation amount of rotation of the motor unit by comparing the amount of rotation of the wheel according to the detected steering angle with the amount of rotation of the wheel according to the detected rotation angle [S280]. The torque angle sensor can detect the steering angle according to the rotation of the steering shaft connected to the steering wheel. Since the steering angle according to the rotation of the steering wheel by the driver is detected, the steering angle detected by the torque angle sensor may be the rotation angle of the wheel intended by the driver.

As described above, the motor unit is driven according to the detected steering angle, and the auxiliary steering force provided by the motor unit is reflected to rotate the sector shaft. As the sector shaft rotates, the steering force is transmitted to the rack through a pitman arm, tie rod, or the like, and the wheel rotates according to the movement of the rack. Since the angle sensor is installed on the sector shaft, and the rotation of the sector shaft is associated with the rotation of the wheel, the rotation angle detected by the angle sensor will be the actual rotation angle of the wheel with an error that can occur in the process of calculating or transmitting the auxiliary steering force. You can.

The control unit may calculate a compensated rotation amount of the motor unit such that the rotation amount of the wheel according to the detected rotation angle reaches the rotation amount of the wheel according to the detected steering angle. The control unit may control the rotation amount of the motor unit according to the calculated amount of compensation rotation. Accordingly, errors that may occur while passing through the first reduction unit and the second reduction unit during steering control may be compensated.

That is, when the rotation angle to which the sector shaft is to be rotated is not satisfied compared to the steering angle of the steering wheel, the control unit may control the motor unit to perform position control to further rotate the sector shaft according to the calculated amount of compensation rotation. According to an example, the control unit may perform position control using proportional integral control. The auxiliary steering force provided as the motor further rotates based on the amount of rotational rotation may be used for position control for further moving the rack by further rotating the sector shaft connected through the rack and the pitman arm.

According to this, the amount of rotation of the wheel can be adjusted to accurately reflect the driver's actual steering will by controlling the amount of rotation of the motor according to the amount of compensation calculated by comparing the steering angle according to the steering of the steering wheel and the rotation angle of the sector shaft. have. In addition, by calculating the compensated rotation amount of the motor unit according to the actual rotation amount of the sector shaft using the angle sensor installed in the sector shaft, it is possible to more accurately adjust the rotation amount of the wheel.

The present disclosure described above can be embodied as computer readable codes on a medium in which a program is recorded. The computer-readable medium includes any kind of recording device in which data readable by a computer system is stored. Examples of computer-readable media include a hard disk drive (HDD), solid state disk (SSD), silicon disk drive (SDD), ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage device. This includes, and is also implemented in the form of a carrier wave (eg, transmission over the Internet).

The above description and the accompanying drawings are merely illustrative of the technical spirit of the present disclosure, and those of ordinary skill in the art to which the present disclosure pertains combine configurations in a range that does not depart from the essential characteristics of the present disclosure. , Various modifications and variations such as separation, substitution and change will be possible. Therefore, the embodiments disclosed in the present disclosure are not intended to limit the technical spirit of the present disclosure, but to explain the scope, and the scope of the technical spirit of the present disclosure is not limited by the embodiments. That is, within the scope of the present disclosure, all of the constituent elements may be selectively combined and operated. The scope of protection of the present disclosure should be interpreted by the claims below, and all technical spirits within the scope equivalent thereto should be interpreted as being included in the scope of the present disclosure.

100: electric power steering device 110: motor unit
130: sensor unit 150: control unit
160: first reduction unit 170: second reduction unit
180: steering wheel 190: steering shaft

Claims (14)

A motor unit including a first motor providing a force for moving the rack and a second motor synchronizing with the first motor to provide a force for moving the rack;
A sensor unit including a torque angle sensor for detecting a torque value and a steering angle according to steering of the steering wheel, and an angle sensor for detecting a rotation angle of a sector shaft; And
A control unit controlling the motor unit according to the steering of the steering wheel, calculating a compensated rotation amount of the motor unit based on the steering angle and the rotation angle, and controlling the rotation amount of the motor unit according to the compensated rotation amount;
Electric power steering device comprising a. The method of claim 1,
The motor unit,
Through the first reduction unit having a power transmission structure by the meshing of the worm and the worm wheel, a force is applied to the rack by driving force to be transmitted to the ball screw of the second reduction unit having a power transmission structure using a ball screw and a ball nut. Motorized power steering to ensure transmission. According to claim 2,
The torque angle sensor,
An electric power steering device connected between the steering wheel and the first reduction unit to detect a torque value and a steering angle according to twisting and rotation of the steering shaft by being connected to the steering shaft. According to claim 2,
The angle sensor,
The electric power steering apparatus installed on the sector shaft rotated according to the sliding of the ball nut included in the second reduction unit to detect a rotation angle of the sector shaft. The method of claim 4, wherein
The angle sensor,
When the sector gear rotates according to the sliding of the ball nut and at least one magnet formed on one surface of the sector gear formed on the outer circumference of the sector shaft and engaged with the ball nut, the magnetic field is sensed by the at least one magnet Electric power steering device comprising a magnetic sensor. The method of claim 5,
The magnetic sensor,
An electric power steering device installed on a housing surrounding the sector shaft and the sector gear opposite to the at least one magnet. The method of claim 1,
The control unit,
Comparing the amount of rotation of the wheel calculated according to the steering angle and the amount of rotation of the wheel calculated according to the rotation angle, calculates the compensation rotation amount, and applies a compensation current based on the compensation rotation amount to the motor unit Electric power steering. The method of claim 7,
The control unit,
An electric power steering device that performs position control of the motor unit using proportional integral control (PI control). A method for controlling an electric power steering device of a vehicle,
Controlling the motor unit according to the steering of the steering wheel;
Detecting a torque value and a steering angle according to steering of the steering wheel;
Detecting a rotation angle of the sector shaft;
Calculating a compensation rotation amount of the motor unit by comparing the steering angle with the rotation angle; And
Controlling a rotation amount of the motor unit according to the compensation rotation amount;
Control method of the electric power steering apparatus comprising a. The method of claim 9,
The step of detecting the torque value and the steering angle,
A control method of an electric power steering device that detects a torque value and a steering angle according to the twist and rotation of the steering shaft. The method of claim 10,
The step of detecting the rotation angle of the sector shaft,
A control method of an electric power steering apparatus that detects the magnetism of at least one magnet installed in the sector shaft and detects a rotation angle of the sector shaft. The method of claim 9,
The step of calculating the compensation rotation amount of the motor unit,
The control method of the electric power steering apparatus for calculating the amount of compensation rotation by comparing the rotation amount of the wheel calculated according to the steering angle and the rotation amount of the wheel calculated according to the rotation angle. The method of claim 12,
Controlling the amount of rotation of the motor unit,
A control method of an electric power steering apparatus that applies a compensation current based on the compensation rotation amount to the motor unit. The method of claim 13,
Controlling the amount of rotation of the motor unit,
A control method of an electric power steering apparatus that performs position control of the motor unit using PI control.

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