JP2008284962A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device capable of performing a request for storage to store the midpoint position of a steering shaft. <P>SOLUTION: The electric power steering device has a storage requesting unit to request the storage of the midpoint position of a steering shaft, and a midpoint position storage unit to store the midpoint position of the steering shaft. The storage requesting unit performs the request for storage when performing the steering operation to satisfy the predetermined condition, and stores the midpoint position of the steering shaft in the midpoint position storage unit when the request for storage is made. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides an electric power provided with a midpoint position storage unit that stores a midpoint position when a steering operation satisfying a predetermined condition is performed, and a storage request is made to store the midpoint position of the steering shaft. The present invention relates to a steering device.

  The general configuration of the electric power steering apparatus will be described with reference to FIG. It is connected to the tie rod 6. The column shaft 2 is provided with a torque sensor 10 that detects the steering torque of the steering wheel 1, and a motor 20 that assists the steering force of the steering wheel 1 is connected to the column shaft 2 via the reduction gear 3. . Electric power is supplied from the battery 14 to the control unit 100 that controls the electric power steering apparatus, and an ignition key signal is input via the ignition key 11. The control unit 100 is mainly composed of a CPU (or MPU or MCU), and a steering assist command for assisting (steering assist) based on the steering torque T detected by the torque sensor 10 and the vehicle speed V detected by the vehicle speed sensor 12. The value I is calculated, and the current supplied to the motor 20 is controlled based on the calculated steering assist command value I.

  In such an electric power steering apparatus, a steering angle sensor is used to detect the steering angle of the steering wheel. For example, Japanese Patent Laid-Open No. 2005-91137 (Patent Document 1) discloses a sensor wheel that operates in conjunction with rotation of a steering wheel and an absolute steering angle that calculates an absolute steering angle based on a steering angle signal from the sensor wheel. A rudder angle sensor provided with a calculation means is disclosed. The sensor wheel includes a GMR (Giant Magnetic Resistance) element and a magnetized portion arranged around the GMR element, and changes in the resistance value of the GMR element obtained by changing the direction of the magnetic field as the magnetized portion rotates. Based on the above, the rotation angle is detected with two rotations of the steering shaft as one cycle. Further, this steering angle sensor stores a turning direction discriminating means for discriminating the turning direction of the steering wheel and a position where the rotation angle of the steering shaft is 0 °, that is, a midpoint position, and a unique value near this midpoint. A midpoint peculiar value detecting means for detecting is provided.

In the midpoint unique value detecting means, the midpoint position storage request procedure for storing the midpoint position of the steering shaft is as shown in the flowchart of FIG. First, it is determined whether the precondition is satisfied or not (step S301). The precondition is satisfied when, for example, all conditions that the ignition key is ON, the engine is stopped, and related functions and components are normal are satisfied. When the precondition is satisfied, it is confirmed whether or not there is a command request by communication from an external tool such as a diagnostic tool or a development tool (step S302). If there is a command request from the external tool, a storage request It is determined that there is (step S303), and calculation of the midpoint position and storage of the midpoint position are performed. If the precondition is not satisfied in step S301, or if it is determined in step S302 that there is no command request from the external tool, it is determined that there is no storage request and the process ends (step S304).
JP 2005-91137 A

  As described above, in the apparatus described in Patent Document 1, the storage request for storing the midpoint position of the steering shaft is made by external communication of an external tool such as a diagnostic tool or a development tool. Therefore, if an external tool such as a diagnostic tool or a development tool is not connected to the vehicle, there is a problem in that the midpoint position cannot be stored because a request for storing the midpoint position is not made. If the midpoint position cannot be stored, for example, the steering wheel return control does not work correctly, which may cause the driver to feel uncomfortable.

  The present invention has been made under the circumstances described above, and the object of the present invention is when the midpoint position of the steering shaft is not stored even if an external tool such as a diagnosis tool or a development tool is not connected. Alternatively, an object of the present invention is to provide an electric power steering apparatus capable of making a storage request for storing the midpoint position of the steering shaft when it is desired to memorize the midpoint position of the steering shaft again.

  The present invention includes a steering angle sensor that detects a steering angle, calculates a current command value based on the steering torque and the vehicle speed, and controls a motor that applies a steering assist force to the steering mechanism based on the current command value. With regard to the electric power steering apparatus configured as described above, the object of the present invention is to provide a storage requesting unit that requests to store the midpoint position of the steering shaft, and a midpoint position memory to store the midpoint position of the steering shaft. The storage request unit makes a storage request when a steering operation that satisfies a predetermined condition is performed, and stores the midpoint position of the steering shaft when the storage request is made. This is achieved by memorizing the part.

  The object of the present invention is that the steering operation satisfying the predetermined condition is a steering pattern based on the steering torque stored in the steering pattern storage unit, or that the midpoint position storage unit is a nonvolatile memory. Achieved more effectively.

  According to the electric power steering apparatus according to the present invention, when a steering operation satisfying a predetermined condition is performed, a request for storing the midpoint position of the steering shaft is made, and the midpoint position is stored. This is very effective when supplying a vehicle to a trial event where an external tool such as a diagnostic tool or a development tool is not required and a diagnostic tool or a development tool is not ready.

  In addition, there is an advantage that the midpoint position can be easily stored even when the midpoint position needs to be re-stored due to aging of the vehicle in the market.

  In the present invention, when a steering operation that satisfies a predetermined condition is performed, a storage request is made to store the middle position of the steering shaft (rotation angle 0 ° position), and the storage request is made. The middle point position of the steering shaft is stored in the storage unit.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of an electric power steering apparatus according to the present invention. A steering pattern storage unit 101 that stores a steering pattern of the steering torque T detected by the torque sensor 10 in the control unit 100, and a request to store the midpoint position of the steering shaft when a predetermined steering pattern is detected. A storage request unit 102 to perform and a midpoint position storage unit 103 to store the midpoint position of the steering shaft are provided. The other configuration of the electric power steering apparatus is not limited to that shown in FIG.

  The procedure for storing the midpoint position of the steering shaft in such a configuration will be described with reference to the flowchart of FIG. If there is a storage request for the midpoint position (step S101), it is confirmed whether there is a storage request (step S102). If it is confirmed in step S102 that there is a storage request, the midpoint position is calculated (step S103), and the midpoint position is stored in the midpoint position storage unit 103 (step S104). If it is confirmed in step S102 that there is no storage request, calculation of the midpoint position and storage of the midpoint position are not performed, and the process ends. The midpoint position storage unit 103 is a non-volatile memory, and the midpoint position is stored even if the ignition key is turned OFF.

  In the present invention, when a steering operation that satisfies a predetermined condition is performed, a storage request for the midpoint position is made. FIG. 3 shows an example of a procedure for requesting storage of the midpoint position of the steering shaft.

  First, it is determined whether the precondition is satisfied or not (step S201). The precondition is satisfied when, for example, all conditions that the ignition key is ON, the engine is stopped, and related functions and components are normal are satisfied. When it is determined that the precondition is satisfied, it is determined whether or not a steering operation satisfying a predetermined condition is performed (step S202), and when it is determined that a steering operation satisfying a predetermined condition is performed, A storage request is made by the storage request unit 102 provided in the control unit 100 (step S203). If it is determined in step S201 that the precondition is not satisfied, or if it is determined in step S202 that the steering operation satisfying the predetermined condition is not performed, no storage request is made (step S204).

Whether or not the steering operation satisfies a predetermined condition is determined based on whether or not the steering pattern of the steering torque T stored in the steering pattern storage unit 101 provided in the control unit 100 satisfies the predetermined condition. . For example, as shown in FIG. 4, the steering pattern satisfying the predetermined condition is a clockwise torque in which the steering torque T from the neutral state becomes T> T ₂ and the counterclockwise torque in which T <−T _2. but twice, T> T ₂ to become clockwise torque is 2 times, T <carried out in order to steering left-handed torque is 1 times the -T ₂ at time t within _1, during a subsequent time t ₂ The steering torque T is a predetermined steering pattern that maintains the neutral range −T ₂ <T <T ₂ .

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to this, In the range which does not deviate from the meaning, it can change suitably.

It is a block block diagram which shows the structure of the electric power steering apparatus which concerns on this invention. It is a flowchart which shows an example of the procedure which memorize | stores the middle point position of a steering shaft. It is a flowchart which shows an example of the memory | storage request | requirement procedure of the midpoint position of the steering shaft which concerns on this invention. It is a figure which shows an example of the steering pattern which satisfy | fills a predetermined condition. It is a figure showing an example of composition of a general electric power steering device. It is a flowchart which shows the memory | storage request | requirement procedure of the middle point position of the steering shaft by the conventional external tool.

Explanation of symbols

1 Steering wheel 2 Column shaft (steering shaft)
DESCRIPTION OF SYMBOLS 3 Deceleration gear 10 Torque sensor 11 Ignition key 12 Vehicle speed sensor 14 Battery 20 Motor 100 Control unit 101 Steering pattern memory | storage part 102 Storage request | requirement part 103 Midpoint position memory | storage part

Claims (3)

A steering angle sensor for detecting a steering angle is provided, a current command value is calculated based on the steering torque and the vehicle speed, and a motor for applying a steering assist force to the steering mechanism is controlled based on the current command value. In the electric power steering apparatus according to the present invention, the electric power steering apparatus includes: a storage requesting unit that requests to store the midpoint position of the steering shaft; and a midpoint position storage unit that stores the midpoint position of the steering shaft. An electric power characterized in that a storage request is made when a steering operation satisfying a predetermined condition is performed, and the midpoint position of the steering shaft is stored in the midpoint position storage section when there is the storage request. Steering device. The electric power steering apparatus according to claim 1, wherein the steering operation satisfying the predetermined condition is a steering pattern based on the steering torque stored in a steering pattern storage unit. The electric power steering apparatus according to claim 1, wherein the midpoint position storage unit is a nonvolatile memory.

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