JP2009248614A - Control device of electric power steering system - Google Patents

Abstract

A control device for an electric power steering device capable of suppressing energy consumption of a relay and achieving energy saving and fuel efficiency improvement is provided.
A control device for an electric power steering apparatus, comprising a power relay and / or a motor relay. After the engine is started, the relay is turned off when a predetermined condition is satisfied, such as when the ignition switch is on and the instruction current to the motor is continuously zero for a certain period of time. .
[Selection] Figure 2

Description

  The present invention relates to a control device for an electric power steering device.

  In a steering system of an automobile, a power steering device that performs steering assist using an external power source is widely employed, and conventionally, a method of driving a vane type hydraulic pump by an engine has been used. However, in this hydraulic system, since the drive loss of the engine due to the constant driving of the hydraulic pump is large and the traveling fuel consumption is also reduced, in recent years, an electric power steering device using an electric motor as a power source is common. is there.

  During the operation of the electric power steering apparatus, the power supply relay and / or the motor relay included in the electric power steering apparatus are always kept on (ON). Is flowing.

By the way, the current used to drive the excitation coil is supplied from a battery or alternator mounted on the vehicle, and its magnitude is several hundred mA (for example, about 0.3 to 0.4 A). This is disadvantageous in terms of energy saving.
In addition, continuing to pass the current affects the fuel efficiency of the vehicle, and there is room for improvement in terms of improving fuel efficiency.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a control device for an electric power steering device that can achieve energy saving and improved fuel efficiency.

  A control device for an electric power steering device according to the present invention (hereinafter, also simply referred to as “control device”) is a control device for an electric power steering device provided with a power supply relay and / or a motor relay. The relay is configured to be turned off when a predetermined condition is satisfied while the switch is on.

  In the control device of the present invention, the power supply relay and / or the motor relay included in the electric power steering device is turned off when a predetermined condition is satisfied after the engine is started and the ignition switch is on. It is configured. Thereby, the consumption current of the excitation coil of the power supply relay and / or the motor relay can be suppressed, and energy saving and fuel consumption improvement can be achieved.

  When the shift lever is at the stop position, the command current to the motor is substantially zero for a predetermined time, the detected torque value is substantially zero for a predetermined time, and the vehicle speed is constant. It may be at least one of being zero for a continuous time and non-detection of the seating of the driver on the driving seat. When the shift lever is at the stop position, the electric power steering device is used when the indicated current to the motor is substantially zero for a certain period of time, or when the detected torque value is substantially zero for a certain period of time. It can be considered that there is no possibility of use (driving a motor to assist steering). Therefore, in such a case, by turning off the power supply relay and / or the motor relay included in the electric power steering device, the current consumption of the exciting coil of the relay can be suppressed, and energy saving and fuel consumption improvement can be achieved. Can do.

  When the shift lever is at a position other than the stop position, the command current to the motor is substantially zero for a certain period of time, the detected torque value is substantially zero for a certain period of time, and the vehicle speed is At least zero for a certain period of time, non-detection of the driver's seating on the driving seat, and a change in the engine speed that is substantially zero and the engine speed is equal to or less than a predetermined value. It can be one. When the shift lever is in a position other than the stop position, when the command current to the motor is substantially zero for a certain period of time, when the change in the engine speed is substantially zero and the engine speed is less than a certain value, etc. It can be considered that the electric power steering device is not used and is not likely to be used. Therefore, in such a case, by turning off the power supply relay and / or the motor relay included in the electric power steering device, the current consumption of the exciting coil of the relay can be suppressed, and energy saving and fuel consumption improvement can be achieved. Can do.

  When the shift lever is at the stop position, the conditions for returning the relay that has been turned off are that the shift lever has been operated, the winker operation, the operation to return the parking brake, the door opening / closing of the vehicle, and the headlight It may be at least one of an operation for running the vehicle including turning on being performed and a seating of the driver on the driving seat being detected. When the shift lever is at the stop position, when the operation of the shift lever is performed, or when the driver's seating on the driving seat is detected, the electric power steering device may be used. be able to. Therefore, in such a case, the operation of the electric power steering apparatus can be smoothly performed by returning the relay that has been turned off to the on state.

  The condition for returning the relay that was turned off to the on state is that when the shift lever is other than the stop position, the detected torque value has changed, the command current to the motor has changed, the vehicle speed has changed, and This may be at least one of changes in the engine speed. It can be considered that there is a possibility that the electric power steering apparatus may be used when the detected torque value changes or the command current to the motor changes when the shift lever is other than the stop position. Therefore, in such a case, the operation of the electric power steering apparatus can be smoothly performed by returning the relay that has been turned off to the on state.

  According to the control device for the electric power steering apparatus of the present invention, it is possible to suppress the current consumption of the relay and achieve energy saving and fuel efficiency improvement.

Hereinafter, embodiments of a control device of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating a schematic configuration mainly including an electric circuit of an electric power steering apparatus. In the electric power steering apparatus 1 shown in FIG. 1, the steering apparatus 2 includes a driver's steering torque applied to a steering wheel (handle) 3 and a motor 4 to a steering shaft 2a via a speed reducer (not shown). Driven by the steering assist force transmitted. The motor 4 is a three-phase brushless motor and is driven by a drive circuit 5. The control circuit 6 which is a control device includes a microcomputer, determines a necessary steering assist force based on a vehicle speed signal input from the vehicle speed sensor 7 and a steering torque signal input from the torque sensor 8, The drive circuit 5 is controlled so that the steering assist force is applied to the steering shaft 2a.

A voltage of the main power supply 9 is applied to the drive circuit 5. The main power source 9 includes a battery 9B and an alternator (having rectification and regulator functions) 9A.
The electric power steering apparatus includes an electric relay and / or a motor relay (not shown) for control. The feature of the present invention is to an excitation coil of the electric relay and / or the motor relay. Is turned off when a predetermined condition is satisfied, and current consumption of the electric power steering apparatus is suppressed.

  The “predetermined condition” for turning off the relay is considered that the electric power steering device is not used and has no possibility of use after the engine is started and the ignition switch is on. This is a condition corresponding to the case, and is slightly different depending on whether the shift lever of the vehicle is at the stop position or other than the stop position.

  When the shift lever is at the stop position, the predetermined condition is that the instruction current to the motor 4 is continuously zero for a certain time (for example, about 3 to 5 seconds), and the torque value detected by the torque sensor 8 Is continuously zero for a certain time (for example, about 3 to 5 seconds), the vehicle speed detected by the vehicle speed sensor 7 is continuously zero for a certain time (for example, about 3 to 5 seconds), and In this case, at least one of non-detection of the driver's seating on the driving seat may be satisfied. As an example of the case where the driver's seating on the driver's seat is not detected, a case where the driver stops the vehicle and makes a purchase with a vending machine on the roadside can be given. The driver's seating on the driving seat can be detected, for example, by arranging a load sensor under the driving seat.

  When the shift lever is at the stop position, the electric power steering device 1 is not used and used (for steering assistance) when the command current to the motor 4 is substantially zero for a certain period of time. It can be considered that there is no possibility of driving the motor 4. Therefore, in such a case, by turning off the power supply relay and / or the motor relay included in the electric power steering apparatus 1, it is possible to suppress the current consumption of the exciting coil of the relay, thereby achieving energy saving and fuel efficiency improvement. be able to.

  On the other hand, when the shift lever is in a position other than the stop position, the predetermined condition is that the instruction current to the motor 4 is continuously zero for a certain period of time, and the torque value detected by the torque sensor 8 is continued for a certain period of time. It is substantially zero, the vehicle speed detected by the vehicle speed sensor 7 is continuously zero for a certain period of time, the seating of the driver on the driving seat is not detected, and the change in the engine speed is substantially zero. And at least one of the engine speeds being equal to or less than a certain value (for example, about 700 rpm) can be satisfied. As an example of the case where the vehicle speed detected by the vehicle speed sensor 7 continues to be zero for a certain time, a case where the vehicle is stopped for a certain time or more while waiting for a signal can be given.

  When the shift lever is in a position other than the stop position, when the command current to the motor 4 is substantially zero for a certain period of time, the change in the engine speed is substantially zero and the engine speed is equal to or less than a certain value. For example, it can be considered that the electric power steering apparatus 1 is not used and is not likely to be used. Therefore, in such a case, by turning off the power supply relay and / or the motor relay included in the electric power steering apparatus 1, it is possible to suppress the current consumption of the exciting coil of the relay, thereby achieving energy saving and fuel efficiency improvement. be able to.

  FIG. 2 is a flowchart showing a procedure for turning off the relay when the shift lever is at the stop position, and FIG. 3 is a flowchart showing a procedure for turning off the relay when the shift lever is at a position other than the stop position. .

  In FIG. 2, the CPU of the microcomputer included in the control circuit 6 determines whether or not the instruction current to the motor 4 is substantially zero for a predetermined time in step S1, and substantially continues for a predetermined time. If it is determined that it is zero (Yes), in step S5, the energization of the relay exciting coil is turned off. On the other hand, if it is determined that it is not substantially zero for a predetermined time (No), the process proceeds to step S2. Proceed.

Next, in step S2, it is determined whether or not the torque value detected by the torque sensor 8 is substantially zero for a certain period of time. If it is determined that the detected torque value is substantially zero for a certain period of time (Yes), step S5 is performed. In step S3, the energization of the relay exciting coil is turned off. On the other hand, if it is determined that it is not substantially zero continuously for a predetermined time (No), the process proceeds to step S3.
Next, in step S3, it is determined whether or not the vehicle speed detected by the vehicle speed sensor 7 is substantially zero for a certain period of time, and if it is determined that the vehicle speed is substantially zero for a certain period of time (Yes). In step S5, the energization of the relay exciting coil is turned off. On the other hand, if it is determined that it is not substantially zero continuously for a predetermined time (No), the process proceeds to step S4.

  Further, in step S4, it is determined whether or not the seating of the driver on the driving seat is not detected. If not, that is, if it is determined that the driver is not seated on the driving seat (Yes), step S4 is performed. In S5, the energization to the relay exciting coil is turned off.

  In FIG. 3, the CPU of the microcomputer included in the control circuit 6 determines whether or not the instruction current to the motor 4 is substantially zero for a certain time in step S11, and continues for a certain time. If it is determined that it is substantially zero (Yes), in step S16, the energization of the relay exciting coil is turned off. Proceed with the process.

Next, in step S12, it is determined whether or not the torque value detected by the torque sensor 8 is substantially zero for a certain period of time. If it is determined that the torque value is substantially zero for a certain period of time (Yes), step S16 is performed. In step S13, the energization of the relay exciting coil is turned off. On the other hand, if it is determined that it is not substantially zero continuously for a predetermined time (No), the process proceeds to step S13.
Next, in step S13, it is determined whether or not the vehicle speed detected by the vehicle speed sensor 7 is substantially zero for a certain period of time, and if it is determined that the vehicle speed is substantially zero for a certain period of time (Yes). In step S16, the energization of the relay exciting coil is turned off. On the other hand, when it is determined that the relay is not substantially zero continuously for a predetermined time (No), the process proceeds to step S14.

  Further, in step S14, it is determined whether or not the driver's seating on the driving seat is not detected. If not, that is, if it is determined that the driver is not seated on the driving seat (Yes), step S14 is performed. If the energization of the relay exciting coil is turned off in S16, on the other hand, if it is determined that the seating of the driver is detected (No), the process proceeds to step S14.

  Then, in step S15, it is determined whether or not the change in the engine speed is substantially zero and the engine speed is equal to or less than a predetermined value, and the change in the engine speed is substantially zero and the engine speed is If it is less than the predetermined value (Yes), in step S16, the energization of the relay exciting coil is turned off.

  When steering assistance by the motor 4 is necessary, it is necessary to return the energization to the excitation coil that has been turned off to the on state. In this embodiment, when the shift lever is at the stop position, the operation of the shift lever has been performed, the winker operation, the operation of returning the parking brake, the opening / closing of the vehicle door, and the headlight on for vehicle traveling. It may be at least one of the operation performed and the detection of the driver's seating on the driving seat. When the shift lever is at the stop position, when the operation of the shift lever is performed, or when the driver's seating on the driving seat is detected, the electric power steering device may be used. be able to. Therefore, in such a case, the operation of the electric power steering apparatus can be smoothly performed by returning the relay that has been turned off to the on state.

  In addition, when the shift lever is at a position other than the stop position, at least one of that the detected torque value has changed, the command current to the motor has changed, the vehicle speed has changed, and the engine speed has changed Can do. It can be considered that there is a possibility that the electric power steering apparatus may be used when the detected torque value changes or the command current to the motor changes when the shift lever is other than the stop position. Therefore, in such a case, the operation of the electric power steering apparatus can be smoothly performed by returning the relay that has been turned off to the on state.

  FIG. 4 is a flowchart showing a procedure for returning the relay that has been turned off when the shift lever is at the stop position, and FIG. 5 is a flowchart for turning off the relay that was turned off when the shift lever is at a position other than the stop position. It is a flowchart which shows the procedure to reset.

  In FIG. 4, when the CPU of the microcomputer included in the control circuit 6 determines whether or not the shift lever at the stop position has been operated in step S21, and determines that the shift lever has been operated. (Yes) returns the energization of the relay exciting coil to ON in step S24, while if it is determined that the shift lever is not operated (No), the process proceeds to step S22.

  Next, in step S22, it is determined whether or not an operation for driving the vehicle including a winker operation, an operation for returning the parking brake, opening / closing of the vehicle door and turning on the headlight is performed, and the operation for driving the vehicle is performed. If it is determined (Yes), in step S24, energization of the relay exciting coil is turned back on. On the other hand, if it is determined that no operation for vehicle travel is performed (No), the process proceeds to step S23. To proceed.

  Next, in step S22, it is determined whether or not the driver's seating on the driving seat is detected. If detected, that is, if it is determined that the driver is seated on the driving seat (Yes), in step S24. The energization to the relay exciting coil is turned back on.

  In FIG. 5, when the CPU of the microcomputer included in the control circuit 6 determines whether or not the detected torque value by the torque sensor 8 has changed in step S31, and determines that the detected torque value has changed. (Yes) returns the energization to the exciting coil of the relay to ON in step S35, while if it is determined that the detected torque value has not changed (No), the process proceeds to step S32.

  Next, in step S32, it is determined whether or not the instruction current to the motor 4 has changed. If it is determined that the instruction current to the motor 4 has changed (Yes), in step S35, the energization of the relay exciting coil is performed. On the other hand, if it is determined that the command current to the motor 4 has not changed (No), the process proceeds to step S33.

  Next, in step S33, it is determined whether or not the vehicle speed detected by the vehicle speed sensor 7 has changed. If it is determined that the vehicle speed has changed (Yes), the energization of the relay excitation coil is turned on in step S35. On the other hand, if it is determined that the vehicle speed has not changed (No), the process proceeds to step S34.

  Further, in step S34, it is determined whether or not the engine speed has changed. If it is determined that the engine speed has changed (Yes), in step S35, energization of the relay excitation coil is turned back on. Let

It is a figure which shows schematic structure mainly having the electric circuit of the electric power steering apparatus. It is a flowchart which shows the procedure which turns off a relay when a shift lever is a stop position. It is a flowchart which shows the procedure which turns off a relay when a shift lever is other than a stop position. It is a flowchart which shows the procedure which returns the relay which turned off in the case where a shift lever is a stop position. It is a flowchart which shows the procedure which returns the relay which turned off in the case where a shift lever is other than a stop position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric power steering apparatus 2 Steering apparatus 3 Steering wheel 4 Motor 5 Drive circuit 6 Control circuit (control apparatus)
7 Vehicle speed sensor 8 Torque sensor

Claims (5)

  A control device for an electric power steering apparatus having a power supply relay and / or a motor relay, wherein after the engine is started, the relay is turned off when a predetermined condition is satisfied with the ignition switch turned on. A control device for an electric power steering device, characterized in that it is configured.   When the shift lever is at the stop position, the predetermined condition is that the command current to the motor is substantially zero for a certain period of time, the detected torque value is substantially zero for a certain period of time, and the vehicle speed is constant. 2. The control device for an electric power steering apparatus according to claim 1, wherein the control device is at least one of zero for a continuous time and non-detection of a driver's seating on a driving seat.   When the predetermined condition is that the shift lever is at a position other than the stop position, the instruction current to the motor is substantially zero for a certain period of time, the detected torque value is substantially zero for a certain period of time, and the vehicle speed is At least zero for a certain period of time, non-detection of the driver's seating on the driving seat, and a change in the engine speed that is substantially zero and the engine speed is equal to or less than a predetermined value. The control device for the electric power steering apparatus according to claim 1, wherein the number is one.   When the shift lever is in the stop position, the condition for returning the relay turned off is that the shift lever has been operated, the winker operation, the operation to return the parking brake, the vehicle door opening and closing, and the headlight. The electric power steering apparatus according to any one of claims 1 to 3, which is at least one of an operation for running the vehicle including turning on being performed and a seating of the driver on the driving seat being detected. Control device.   The condition for returning the relay that was turned off to the on state is that when the shift lever is other than the stop position, the detected torque value has changed, the command current to the motor has changed, the vehicle speed has changed, and The control device for an electric power steering apparatus according to any one of claims 1 to 3, which is at least one of changes in engine speed.

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