JP2012224280A - Electric power steering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power steering system capable of being suitably started without the start of an engine.SOLUTION: The electric power steering system is provided with an electric motor 4 that provides a steering assistance power to a steering mechanism, an electrically-driven circuit 23 that drives the electric motor 4, and a steering control ECU 130 that controls the electrically-driven circuit 23. The steering control ECU 130 starts the electrically-driven circuit 23 on the basis of a complete explosion information ES, a driving motor movable information MS, a vehicle speed information VS, and a vehicle speed calculation value information TRS obtained through a CAN 130a, and when any abnormality occurs on CAN 130a, starts the electrically-driven circuit 23 on the basis of a torque signal TS and an angle signal θS input through a signal line different from the CAN 130a.

Description

  The present invention relates to an electric power steering apparatus.

An electric power steering device (EPS) provided in a vehicle is driven using power stored in a battery or power generated by a generator as a power source.
Since EPS requires a large amount of energy (electric power energy) for driving an electric motor or the like, for example, when EPS is continuously used in a state where the engine does not start and power is not generated by the generator, the battery is charged. There is a case where power consumption is excessive and power for starting the engine is insufficient.
In order to avoid such a shortage of electric power, for example, in Patent Document 1, the engine start is monitored by the oil pressure of the lubricating oil of the engine or the water temperature supplied to the radiator or the water jacket, and the steering is started when the engine starts. A technique for generating assist force, that is, starting EPS is disclosed.
Further, for example, Patent Document 2 discloses a technique for determining start of an engine when a sudden increase in battery voltage is detected, and starting electric power steering (EPS).

JP 2001-163238 A JP 2003-148308 A

The techniques disclosed in Patent Documents 1 and 2 are techniques for starting up EPS provided in a vehicle that runs on an engine, and engine start is used as an EPS start condition.
However, in recent years, there are hybrid vehicles that run with a vehicle drive unit that combines an engine and a driving motor, and electric vehicles that use only the driving motor as a vehicle drive unit. When a hybrid vehicle runs with a driving motor, Since the engine does not start, the technique disclosed in Patent Documents 1 and 2 has a problem that EPS cannot be started.
Further, when determining engine start based on the engine speed, a signal line for inputting the engine speed to the EPS control device is necessary only for the purpose of determining the start of the EPS, resulting in high production costs. There is a problem of becoming.

  Therefore, an object of the present invention is to provide an electric power steering device that can be suitably started without an engine start signal.

  In order to solve the above problems, an invention according to the present application includes an electric motor that applies a steering assist force to a steering mechanism, a driving device that drives the electric motor, and a control device that controls the driving device. The drive device is started based on information obtained via the information communication means, and when an abnormality occurs in the information communication means, based on a signal input via a signal line different from the information communication means Thus, the electric power steering device is characterized in that the drive device is started.

  According to the present invention, the control device can start the drive device that drives the electric motor of the electric power steering device based on the information obtained through the information communication means. Further, when an abnormality occurs in the information communication means, the control device can start the drive device based on a signal input via a signal line different from the information communication means.

Further, the present invention is characterized in that the information obtained by the control device via the information communication means is at least one of information indicating the behavior of the vehicle and information indicating the state of the vehicle drive unit. .
Therefore, the control device can start the drive device based on the information indicating the behavior of the vehicle and the information indicating the state of the vehicle drive unit.

Further, according to the present invention, the signal input to the control device via the signal line includes a signal indicating the magnitude and direction of the steering torque and the rotation amount and rotation of the rotating shaft to which the steering torque is input in the steering mechanism. It is at least one of signals indicating directions.
Therefore, when an abnormality has occurred in the information communication means, the control device includes a signal indicating the magnitude and direction of the steering torque and a signal indicating the amount of rotation and the direction of rotation of the rotating shaft to which the steering torque is input in the steering mechanism. The drive can be started based on at least one of the following.

Further, according to the present invention, when an abnormality occurs in the information communication means, the control device starts the drive device when the direction of the steering torque coincides with the rotation direction of the rotation shaft. And
Therefore, when an abnormality occurs in the information communication means, the control device can start the drive device when the direction of the steering torque coincides with the rotation direction of the rotary shaft to which the steering torque is input in the steering mechanism.

Further, the present invention is characterized in that the information communication means is a CAN.
Therefore, the control device can start the drive device based on the information indicating the behavior of the vehicle and the information indicating the state of the vehicle drive unit obtained through the CAN.

  According to the present invention, it is possible to provide an electric power steering device that can be suitably started without an engine start signal.

It is a figure of vehicles provided with EPS concerning this embodiment. It is a figure which shows the example of 1 structure of EPS. It is a figure which shows the system | strain of the signal input into steering control ECU. It is a flowchart which shows the procedure which determines the starting of EPS. It is a flowchart which shows another procedure which determines the starting of EPS.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate.
For example, as shown in FIG. 1, the electric power steering device (EPS10) according to the present embodiment has a front wheel 1FL via a power transmission device 12 in which the driving force generated by the vehicle drive unit 11 includes a transmission 12a. , 1FR, and the front wheels 1FL, 1FR are provided in the front wheel drive vehicle 1 that rotates and travels.
When the vehicle 1 is a hybrid vehicle, the vehicle drive unit 11 has, for example, a configuration in which an engine 11a and a travel motor 11b are combined, and a driving force generated by the engine 11a by an electronic control device (vehicle drive control ECU 11c). At least one of the driving forces generated by the traveling motor 11b is selected to cause the vehicle 1 to travel.

Further, the front wheels 1FL, 1FR and rear wheels 1RL, the 1RR, wheel speed sensors _FL S for detecting the rotational speed of each _wheel, FR _S, RL S, the RR _S are provided. The wheel speed sensors FL _S , FR _S , RL _S , RR _S detect, for example, the rotational speed (wheel speed) of each wheel 1FL, 1FR, 1RL, 1RR as the number of pulses per unit time, and the detection signal is a vehicle speed sensor. input to S _V. A vehicle speed sensor _{S V} is the wheel speed sensors _{FL S, FR S, RL S} , each wheel 1FL inputted from RR _S, 1FR, 1RL, and calculates the speed of the vehicle 1 based on the rotation speed of 1RR, computed vehicle speed Is output as vehicle speed information VS.
In the present embodiment, the vehicle speed information VS is one piece of information indicating the behavior of the vehicle 1.
Other motor 4 provided in the vehicle 1, the motor drive circuit 23, described below are details of the torque sensor S _T.

A well-known technique may be used for the configuration of the vehicle drive unit 11, the configuration of the power transmission device 12, and the method of controlling the vehicle drive unit 11 by the vehicle drive control ECU 11c, and detailed description thereof is omitted here.
When the vehicle 1 is driven by the rear wheels, the driving force generated by the vehicle drive unit 11 is transmitted to the rear wheels 1RL and 1RR via the power transmission device 12 and the like, and the rear wheels 1RL and 1RR rotate to cause the vehicle 1 to rotate. Configured to travel.

As shown in FIG. 2, in the EPS 10 according to the present embodiment, a main steering shaft 3a provided with a steering handle 3, a shaft 3c, and a pinion shaft 7 are connected by two universal joints (universal joints) 3b. The pinion gear 7a provided at the lower end portion of the pinion shaft 7 meshes with the rack teeth 8a of the rack shaft 8 that can reciprocate in the vehicle width direction. The left and right front wheels 1FL, 1FR are connected via the. With this configuration, the front wheels 1FL and 1FR are turned with the steering of the steering handle 3, and the traveling direction of the vehicle 1 (see FIG. 1) can be changed.
The pinion shaft 7 is supported by a steering gear box (not shown) through bearings 3d, 3e, and 3f at its upper, middle, and lower portions.

The EPS 10 includes an electric motor 4 that supplies a steering assist force for reducing the steering force by the steering handle 3, and a reduction mechanism in which the output shaft and the pinion shaft 7 of the electric motor 4 are composed of, for example, a plurality of gears. 5, the rotation drive of the output shaft of the electric motor 4 is transmitted to the pinion shaft 7. The steering mechanism includes the steering handle 3, the main steering shaft 3a, the universal joint 3b, the shaft 3c, the speed reduction mechanism 5, the pinion shaft 7, the rack shaft 8, the rack teeth 8a, the tie rods 9 and 9, and the like. .
The electric motor 4 gives a steering assist force to the steering mechanism.

The electric motor 4 is a three-phase brushless motor including a stator (not shown) having a plurality of field coils and a rotor (not shown) that rotates inside the stator, and mechanically transfers electric energy. It is converted into energy (P _M = ωT _M ).
Here, omega is the angular speed of the electric motor 4, T _M is the torque generated by the motor 4.

Further, EPS10 includes a motor drive circuit 23 is a drive device for driving a motor 4, a resolver 25, a torque sensor S _T for detecting the pinion torque T _P applied to the pinion shaft 7, the output of the torque sensor S _T And a differential amplifier circuit 21 for amplifying.
The EPS 10 is controlled by a control device (steering control ECU 130).
In the present embodiment, the pinion torque T _P is a steering torque generated by the steering of the steering wheel 3. The pinion shaft 7 corresponds to a rotating shaft to which a steering torque (pinion torque T _P ) is input in the steering mechanism.

The motor drive circuit 23 includes a plurality of switching elements such as, for example, a three-phase FET bridge circuit, and uses a DUTY (DU, DV, DW) signal output from the steering control ECU 130 as a control signal of the EPS 10. A voltage is generated and the electric motor 4 is driven.
The steering control ECU 130 has a function of detecting a three-phase motor current I (IU, IV, IW) using a hall element (not shown).

The resolver 25 detects an electric motor rotation angle θ _m of the electric motor 4 and outputs an angle signal θS. For example, a sensor for detecting a change in magnetic resistance includes a plurality of irregularities at equal intervals in a circumferential direction of a rotor (not shown). Some of them are close to a magnetic rotating body provided with a portion.

Further, a resolver 25, a motor rotation angle theta _m, preferably configured to detect include the direction of rotation, the angle signal .theta.S, it is preferable to include information that indicates the rotation direction of the motor rotation angle theta _m. For example, the angle of the case (in the case of voltage positive voltage) rotation direction of the motor rotation angle theta _m is the sign of the angle signal θS when the right rotational direction plus a rotation direction of the motor rotation angle theta _m is left rotational direction A configuration in which the sign of the signal θS is negative (in the case of voltage, a negative voltage) is preferable. Steering control ECU130 angle signal .theta.S is inputted by this arrangement, the magnitude and the rotation direction of the motor rotation angle theta _m can be calculated based on the angular signal .theta.S. That is, the steering control ECU 130 can acquire the rotation angle and rotation direction of the output shaft of the electric motor 4.
The rotation direction of the output shaft of the electric motor 4 has a one-to-one correspondence with the rotation direction of the pinion shaft 7, and the steering control ECU 130 acquires the rotation direction of the output shaft of the electric motor 4 to obtain the rotation direction of the pinion shaft 7. Can be obtained.
Therefore, the angle signal θS in the present embodiment is a signal indicating the rotation amount and rotation direction of the pinion shaft 7.

Torque sensor S _T is used to detect the pinion torque T _P applied to the pinion shaft 7, a magnetic film so that the opposite direction of the anisotropy in the axial direction two portions of the pinion shaft 7 is deposited, the A detection coil is inserted on the surface of the magnetic film so as to be separated from the pinion shaft 7.
The differential amplifier circuit 21 amplifies the difference in permeability change between the two magnetostrictive films detected by the detection coil as an inductance change, and outputs a torque signal TS.
And the torque signal TS, it is preferable to include information indicating the direction of the pinion torque T _P. For example, (in the case of voltage positive voltage) direction of the pinion torque T _P is the sign of the torque signal TS when the right plus and the sign of the negative torque signal TS when the direction of the pinion torque T _P is left A configuration of (negative voltage in the case of voltage) is preferable. Steering control ECU130 the torque signal TS is inputted by this configuration can be calculated based the magnitude and direction of the pinion torque T _P to the torque signal TS.
Therefore, the torque signal TS in the present embodiment is a signal indicating the magnitude and direction of the pinion torque T _P (steering torque).

  Further, an ignition switch 22 is connected to the steering control ECU 130 so that an ignition signal IGS for notifying the ignition state (ON, OFF) can be input to the steering control ECU 130. The polarity of the ignition signal IGS is not limited. For example, a signal that has a polarity of zero (ground voltage in the case of voltage) or positive (positive voltage in the case of voltage) when the ignition is on, for example. And it is sufficient.

The steering control ECU 130 has an interface (not shown) of a CAN (Control Area Network) 130a (see FIG. 3) as information communication means, and is configured so that necessary information (signals) can be input via the CAN 130a. For example, as shown in FIG. 3, the vehicle speed sensor _{S V} is connected to the steering control ECU130 via CAN130a, steering control ECU130 the acquired configured to allow the vehicle speed information VS via CAN130a.
Further, the vehicle drive control ECU 11c preferably has an interface (not shown) of the CAN 130a and is connected to the CAN 130a, and the vehicle drive control ECU 11c and the steering control ECU 130 are configured to be able to communicate with each other.
The CAN 130a preferably performs error check using a checksum or parity, and this configuration can improve the reliability of data communication in the CAN 130a. Furthermore, an abnormality of the CAN 130a can be detected.
The vehicle drive control ECU 11c and the steering control ECU 130 may be integrated.

In addition, the signal transmission method in the CAN 130a is not limited. For example, a transmission method (balanced transmission) in which a set of two signal lines is used and a voltage in which plus or minus is inverted in each signal line is transmitted as a signal. In this case, the CAN 130a can be made resistant to noise and can have a long transmission distance.
In addition, when the amount of data communication using the CAN 130a is large and the load on the CAN 130a is large, the vehicle 1 (see FIG. 1) may be provided with a plurality of systems of CAN 130a as necessary.

The resolver 25 and the ignition switch 22 are preferably connected to the steering control ECU 130 via a dedicated line (signal line) different from the CAN 130a, and the angle signal θS and the ignition signal IGS are input to the steering control ECU 130.
Further, the motor drive circuit 23 is also connected to the steering control ECU 130 via a dedicated line (signal line) different from the CAN 130a, DUTY output from the steering control ECU 130 is input to the motor drive circuit 23, and the steering control ECU 130 generates the motor current I. Configured to be detectable.
In this embodiment, the differential amplifier circuit 21 is connected to the steering control ECU 130 via a dedicated line (signal line) different from the CAN 130a, and the torque signal TS is input to the steering control ECU 130.
According to this configuration, even if an abnormality occurs in the CAN 130a, the steering control ECU 130 receives the angle signal θS, the ignition signal IGS, the motor current I, and the torque signal TS.

The steering control ECU 130 configured as described above has a pinion torque T _P detected by the torque sensor S _T (see FIG. 2) when the vehicle 1 (see FIG. 1) equipped with the EPS 10 (see FIG. 2) is traveling. depending on the vehicle speed the vehicle speed sensor S _V is detected, generated by the electric motor 4 (see FIG. 2) a suitable torque T _M for reducing the steering force by the steering wheel 3 (see FIG. 2) as a steering assist force Let

  When the ignition switch 22 (see FIG. 2) is operated by a driver or the like to turn on the ignition and the vehicle 1 (see FIG. 1) is started, the steering control ECU 130 (see FIG. 2) starts the EPS 10 (see FIG. 2). To do. At this time, when the steering handle 3 (see FIG. 2) is steered in a state where a generator (not shown) does not generate power (for example, a state where the engine is stopped in a vehicle using only the engine as a vehicle drive unit). When the steering control ECU 130 controls the electric motor 4 (see FIG. 2) to supply electric power, the electric power source is a battery (not shown). Therefore, when the steering handle 3 is continuously steered and electric power is continuously supplied to the electric motor 4, the electric power stored in the battery is consumed greatly, and for example, the electric power for starting the engine may be insufficient.

Therefore, the steering control ECU 130 (see FIG. 2) according to the present embodiment, when the ignition switch 22 (see FIG. 2) is operated and the ignition is turned on, when a generator (not shown) is generating power, Alternatively, the EPS 10 (see FIG. 2) is activated only when sufficient power is stored in a battery (not shown).
When the steering control ECU 130 according to the present embodiment determines that the ignition is in an ON state by the ignition signal IGS, the generator generates power when one of the following conditions 1 to 3 is satisfied as a first stage. The EPS 10 is activated when it is determined that the battery is in a state in which the battery is charged or a sufficient amount of power is stored in the battery.
Condition 1: When the engine 11a (see FIG. 1) is started, or when traveling by the traveling motor 11b (see FIG. 1) is possible.
Condition 2: When the vehicle speed detected by the power transmission device 12 (see FIG. 1) is equal to or higher than a predetermined threshold.
Condition 3: When the vehicle speed obtained from the wheel speeds of the wheels (front wheels 1FL, 1FR (see FIG. 1) and rear wheels 1RL, 1RR (see FIG. 1)) is equal to or higher than a predetermined threshold.
In the present embodiment, the EPS 10 is activated when the electric motor drive circuit 23 is started and a rectangular wave voltage can be generated when DUTY is input from the steering control ECU 130. In other words, starting the electric motor drive circuit 23 is the activation of the EPS 10.

As described above, when the vehicle 1 (see FIG. 1) is a hybrid vehicle, the vehicle drive unit 11 (see FIG. 1) is a combination of the engine 11a (see FIG. 1) and the traveling motor 11b (see FIG. 1). Composed.
Therefore, the vehicle drive control ECU 11c (see FIG. 1) is configured to monitor the state of the engine 11a and detect that the engine 11a has started.
For example, the vehicle drive control ECU 11c determines that the engine 11a has started when the rotational speed of a crankshaft (not shown) in the engine 11a exceeds a predetermined value (for example, 500 rpm). Then, information indicating that the engine 11a has started (complete explosion information ES) is sent to the CAN 130a. The steering control ECU 130 determines that the engine 11a of the vehicle drive unit 11 has started when the complete explosion information ES is acquired via the CAN 130a. That is, it is determined that the above condition 1 is satisfied.

Further, the vehicle drive control ECU 11c indicates that the vehicle 11a (see FIG. 1) is ready to run when the engine 11a (see FIG. 1) is not started (running motor movable information MS). Is preferably sent to CAN 130a instead of complete explosion information ES.
The vehicle drive control ECU 11c determines the possibility of traveling by the traveling motor 11b based on the state of charge of a battery (not shown) (for example, SOC (state of charge)).
When the steering control ECU 130 determines that traveling by the traveling motor 11b is possible, the steering control ECU 130 sends traveling motor movable information MS to the CAN 130a.
When the steering motor ECU 130 acquires the travel motor movement information MS via the CAN 130a, the steering control ECU 130 determines that the battery has sufficient power to start the travel motor 11b. In this state, even if the EPS 10 is driven, it is determined that the power consumption from the battery does not affect the start of the engine 11a, and it is determined that the above condition 1 is satisfied.

  In the present embodiment, the complete explosion information ES and the traveling motor movable information MS are information indicating the state of the vehicle drive unit 11 (see FIG. 1).

  The power transmission device 12 (see FIG. 1) includes a transmission 12a (see FIG. 1), and the rotational speed of the drive shaft of the transmission 12a is detected by the rotational speed sensor 12b (see FIG. 1). Composed. Further, the vehicle drive control ECU 11c calculates the vehicle speed of the vehicle 1 (see FIG. 1) based on the signal input from the rotational speed sensor 12b, and sends the calculation result to the CAN 130a as vehicle speed calculation value information TRS. When the vehicle speed indicated by the vehicle speed calculation value information TRS acquired via the CAN 130a is equal to or higher than a predetermined threshold (for example, 10 km / h), that is, the steering control ECU 130 determines that the vehicle speed obtained from the rotational speed of the drive shaft of the transmission 12a is predetermined. If it is equal to or greater than the threshold value, it is determined that the above condition 2 is satisfied. In the present embodiment, the vehicle speed calculation value information TRS is one piece of information indicating the behavior of the vehicle 1.

Further, the vehicle 1 (see FIG. 1) as described above calculates a vehicle speed based on the wheel speed, the vehicle speed sensor S _V for inputting the calculated vehicle speed to the steering control ECU130 through CAN130a is provided. When the vehicle speed indicated by the vehicle speed information VS acquired via the CAN 130a is equal to or higher than a predetermined threshold (for example, 10 km / h), the steering control ECU 130, that is, the wheels 1FL, 1FR, 1RL, 1RR (see FIG. 1). When the vehicle speed calculated | required from wheel speed is more than a predetermined threshold value, it determines with above-mentioned condition 3 being satisfy | filled.

  As described above, when the steering control ECU 130 (see FIG. 2) determines that the ignition is in the ON state based on the ignition signal IGS, the above-described conditions 1 to 3 are determined, and at least one of the conditions 1 to 3 is satisfied. In the event of a failure, the EPS 10 (see FIG. 2) is activated. That is, the motor drive circuit 23 (see FIG. 2) is started.

When all of the above conditions 1 to 3 are not satisfied, the steering control ECU 130 shown in FIG. 2 determines whether or not the CAN 130a (see FIG. 3) is abnormal as the second stage. When the two conditions are both satisfied, the EPS 10 is activated.
Condition 4: When the value of the pinion torque _TP is equal to or greater than a predetermined threshold value.
Condition 5: the direction of the pinion torque T _P, when the rotation direction of the pinion shaft 7 matches.

As shown in FIG. 2, the pinion shaft 7 is mounted a torque sensor S _T, detects the pinion torque T _P generated in the pinion shaft 7, such as when the steering wheel 3 is steered. Then, the torque sensor _{S T} pinion torque _{T P} detected is inputted to the steering control ECU130 is converted to a torque signal TS in the differential amplifier circuit 21. Steering control ECU130 can calculates the magnitude and direction of the pinion torque T _P occurring on the pinion shaft 7 on the basis of the torque signal TS that is input.
Furthermore, the torque signal TS in the present embodiment is configured to be input to the steering control ECU130 without using CAN130a, steering control even if an abnormality has occurred in CAN130a ECU130 is calculating the magnitude and direction of the pinion torque _{T P} it can.

Further, the EPS10 equipped with a resolver 25 for detecting a motor rotation angle theta _m of the motor 4, it converts the detected motor rotation angle theta _m to the angle signal .theta.S. The angle signal θS output from the resolver 25 is configured to input to the steering control ECU130, steering control ECU130 is the magnitude and rotation direction of the motor rotation angle theta _m of the electric motor 4 based on the input angle signal θS Can be calculated.
Furthermore, the angle signal θS in the present embodiment is configured to be input to the steering control ECU130 without using CAN130a, steering control ECU130 even if an abnormality has occurred in CAN130a the magnitude and rotation direction of the motor rotation angle theta _m Can be calculated.

For example, when the steering handle 3 is operated in a state where the EPS 10 is not activated, the resolver 25 rotates the motor rotation angle θ _m of the motor 4 when the output shaft of the motor 4 rotates with the rotation of the pinion shaft 7. if the detected outputs an angle signal θS to configure the steering control ECU130 can calculates the magnitude and rotation direction of the motor rotation angle theta _m generated by the operation of the steering wheel 3. Further, the calculated electric motor rotation angle θ _m can be set as the magnitude and rotation direction of the steering angle of the pinion shaft 7. That is, the steering control ECU 130 can calculate the rotation direction of the pinion shaft 7. Then, it compares the rotational direction of the direction and the pinion shaft 7 of the pinion torque T _P occurring on the pinion shaft 7.

In addition, by adding the condition 5 to the activation condition of the EPS 10, the activation of the EPS 10 when the steering operation of the vehicle 1 (see FIG. 1) by the steering handle 3 is not performed is avoided.
When the steering handle 3 is steered, the pinion shaft 7 rotates in the steering direction, and the output shaft of the electric motor 4 rotates corresponding to the rotation direction of the pinion shaft 7. Therefore, the direction of the pinion torque T _P generated in the pinion shaft 7, the rotation direction of the pinion shaft 7 coincides.
On the other hand, when the front wheels 1FL and 1FR turn due to an influence from the road surface such as a rudder (occurrence of so-called steering wheel removal), the driver steers the steering handle 3 to the side opposite to the turning direction of the front wheels 1FL and 1FR. . Thus, the front wheels 1FL, the rotational direction of the pinion shaft 7 rotated by turning the 1FR, direction of the pinion torque T _P generated in the pinion shaft 7 by the steering of the steering wheel 3 is in the opposite direction.
In other words, the configuration of the steering control ECU130 starts the EPS10 when the condition 5 is satisfied, when the pinion torque T _P occurs omissions like steering wheel pull can be configured to EPS10 does not start.

  As described above, the steering control ECU 130 according to this embodiment has an abnormality in the CAN 130a and satisfies both the above-described conditions 4 and 5 when all of the above-described conditions 1 to 3 are not satisfied with the ignition turned on. And is configured to activate the EPS 10.

With reference to FIG. 4, the procedure by which the steering control ECU 130 activates the EPS 10 when the ignition is turned on will be described (see FIGS. 1 to 3 as appropriate).
The steering control ECU 130, for example, repeatedly executes the procedure shown in FIG. 4 at a predetermined interval (for example, 100 msec interval), and controls the activation of the EPS 10.

The steering control ECU 130 determines the ignition state based on the ignition signal IGS transmitted from the ignition switch 22 (step S1). If the ignition is not ON (step S1 → No), the EPS 10 is not started (step S8). The process is terminated.
At this time, if the EPS 10 is activated, the steering control ECU 130 stops the EPS 10 (step S8).

On the other hand, when the ignition is ON (step S1 → Yes), the steering control ECU 130 determines whether or not the engine 11a is started (determination of condition 1).
Specifically, the steering control ECU 130 determines whether or not the engine 11a is in a complete explosion state or whether or not the traveling motor 11b can travel (step S2). When the steering control ECU 130 acquires the complete explosion information ES or the traveling motor movable information MS via the CAN 130a in step S2, the steering control ECU 130 determines that the engine 11a is in the complete explosion state or can travel with the traveling motor 11b ( In step S2 → Yes, the EPS 10 is activated (step S9).

When the complete explosion information ES and the travel motor movable information MS cannot be acquired via the CAN 130a, the steering control ECU 130 determines that the engine 11a is not in the complete explosion state and travel by the travel motor 11b is not possible ( Step S2 → No). That is, the steering control ECU 130 determines that the engine 11a has not been started. Further, it is determined that the traveling motor 11b cannot be started. Then, the steering control ECU 130 determines whether or not the vehicle speed detected by the power transmission device 12 is equal to or higher than a predetermined threshold (condition 2 determination).
Specifically, the steering control ECU 130 sets the vehicle speed indicated by the vehicle speed calculation value information TRS acquired via the CAN 130a as the vehicle speed (first vehicle speed) detected by the transmission 12a, and the first vehicle speed is a predetermined threshold (first threshold). ) When above (step S3 → Yes), the steering control ECU 130 activates the EPS 10 (step S9).
The first threshold value may be a value that is appropriately set by experimental measurement or the like, for example, 10 km / h as described above.

When the first vehicle speed is less than the first threshold value (step S3 → No), the steering control ECU 130 determines whether or not the vehicle speed obtained from the wheel speed is equal to or higher than a predetermined threshold value (determination of condition 3).
Specifically, the steering control ECU 130 sets the vehicle speed indicated by the vehicle speed information VS acquired via the CAN 130a as the vehicle speed (second vehicle speed) obtained from the wheel speeds of the wheels 1FL, 1FR, 1RL, 1RR, and the second vehicle speed is When it is equal to or greater than the predetermined threshold (second threshold) (step S4 → Yes), the steering control ECU 130 activates the EPS 10 (step S9).
The second threshold may be a value that is appropriately set by experimental measurement or the like, for example, 10 km / h as described above.

  When the second vehicle speed is less than the second threshold (step S4 → No), the steering control ECU 130 determines whether or not an abnormality has occurred in the CAN 130a (step S5). This method is not particularly limited. For example, as described above, when the error check using the checksum and parity is performed in the CAN 130a, the steering control ECU 130 determines that the complete explosion information ES, the traveling motor movable information MS, the vehicle speed is detected by the checksum error and the parity error. What is necessary is just to set it as the structure which determines with abnormality having generate | occur | produced in CAN130a, when calculation value information TRS and vehicle speed information VS cannot be acquired. And when abnormality has not generate | occur | produced in CAN130a (step S5-> No), steering control ECU130 does not start EPS10 (step S8), and complete | finishes a process.

Meanwhile, when an abnormality has occurred in the CAN130a (step S5 → Yes), the steering control ECU130 determines whether or not the value of the pinion torque _{T P} is a predetermined threshold value (reference torque value) or more (judgment condition 4) .
Specifically steering control ECU130 calculates the pinion torque T _P based on the torque signal TS inputted from the differential amplifier circuit 21, when the calculated pinion torque T _P is smaller than the reference torque value (step S6 → No) The EPS 10 is not activated (step S8), and the process is terminated.
The reference torque value may be a value that is appropriately set by experimental measurement or the like.

On the other hand, when the calculated pinion torque T _P is equal to or greater than the reference torque value (step S6 → Yes), steering control ECU130 determines whether or not the rotational direction of the direction and the pinion shaft 7 of the pinion torque T _P coincides ( Determination of condition 5).
Specifically steering control ECU130 calculates the direction of the pinion torque T _P by the sign of the torque signal TS inputted from the differential amplifier circuit 21, further, the pinion shaft by the sign of the angle signal θS inputted from the resolver 25 7 Calculate the direction of rotation.
When the direction of rotation of the direction of the pinion shaft 7 of the pinion torque _{T P} match (step S7 → Yes), Start EPS10 (step S9) is the process ends, the direction and the pinion shaft of the pinion torque _{T P} 7 does not coincide with each other (step S7 → No), the EPS 10 is not started (step S8), and the process is terminated.

As described above, the steering control ECU 130 (see FIG. 2) for controlling the EPS 10 (see FIG. 2) according to the present embodiment acquires the vehicle drive unit 11 (see FIG. 1) obtained through the CAN 130a (see FIG. 3). The EPS 10 can be activated based on information indicating the state (complete explosion information ES, traveling motor movable information MS) and information indicating the behavior of the vehicle 1 (see FIG. 1) (vehicle speed calculation value information TRS, vehicle speed information VS).
When the above-described condition 1 is satisfied, the steering control ECU 130 activates the EPS 10 so that the engine 11a (see FIG. 1) does not start and is not generated by a generator (not shown), and a battery ( It is possible to prevent the EPS 10 from starting when a sufficient amount of power is not stored in the battery (not shown), and to prevent the power stored in the battery (not shown) from being consumed violently.

Further, because the steering control ECU 130 (see FIG. 2) starts the EPS 10 (see FIG. 2) when the above-described conditions 2 and 3 are satisfied, the engine 11a (see FIG. 1) is not in a complete explosion state, and Even if the traveling motor 11b (see FIG. 1) cannot be started, the steering control ECU 130 can start the EPS 10 if one of the first vehicle speed and the second vehicle speed is greater than the threshold value.
For example, even if the vehicle 1 (see FIG. 1) starts to run downhill when the engine 11a is stopped due to idle stop, the EPS 10 is activated and the vehicle 1 can be steered with a suitable steering feeling. In addition, such a state is often temporary, and the EPS 10 is rarely operated continuously. Therefore, it is avoided that the electric power stored in the battery is consumed violently.

Furthermore, based on the two vehicle speeds, the first vehicle speed detected by the transmission 12a (see FIG. 1) and the second vehicle speed obtained from the wheel speeds of the wheels 1FL, 1FR, 1RL, 1RR (see FIG. 1), The steering control ECU 130 (see FIG. 2) determines the activation of the EPS 10 (see FIG. 2), so that either the rotational speed sensor 12b (see FIG. 1) or the vehicle speed sensor S _V (see FIG. 1) is used. It is possible to incorporate a fail-safe function in which the steering control ECU 130 can preferably activate the EPS 10 even when an abnormality occurs.

  In addition, when an abnormality occurs in the CAN 130a (see FIG. 3), the steering control ECU 130 (see FIG. 2), based on the signals (torque signal TS, angle signal θS) that can be acquired without going through the CAN 130a, the EPS 10 (FIG. 2). Can be started. With this configuration, even when an abnormality has occurred in the CAN 130a, the EPS 10 is activated as appropriate, and a reduction in steering feeling can be prevented. That is, it is possible to incorporate a fail-safe function in which the steering control ECU 130 can preferably activate the EPS 10 even when an abnormality occurs in the CAN 130a.

Further, the steering control ECU 130 (see FIG. 2), depending on the conditions 4 and 5 above, the pinion shaft 7 reference torque value or greater pinion torque _{T P} (see FIG. 2) is generated, and its pinion torque _{T P} The EPS 10 (see FIG. 2) can be activated only when it occurs based on the driver's intention (in this case, the intention to steer the vehicle 1 (see FIG. 1)). That is, when the driver does not intend to steer the vehicle 1, the EPS 10 does not start, and it is possible to suppress power consumption of a battery (not shown).

  Further, since the steering control ECU 130 (see FIG. 2) does not determine the activation of the EPS 10 (see FIG. 2) based only on the state of the engine 11a (see FIG. 1), for example, the driving motor 11b ( Even when the vehicle 1 (see FIG. 1) travels only by referring to FIG. 1, the EPS 10 is activated, and the steering feeling can be prevented from being lowered.

  Further, the steering control ECU 130 (see FIG. 2) does not need to detect the rotational speed of the crankshaft (not shown) of the engine 11a (see FIG. 1), and the signal line for inputting the rotational speed of the crankshaft to the steering control ECU 130. Can be reduced. With this configuration, the cost of the EPS 10 (see FIG. 2) can be reduced, and the cost of the vehicle 1 (see FIG. 1) can be reduced.

  In the flowchart shown in FIG. 4, when all of Steps S2 to S4 are “No”, that is, when all of the conditions 1 to 3 are not satisfied, the steering control ECU 130 has an abnormality in the CAN 130a (see FIG. 3). It is determined whether or not it is determined, but a configuration in which this determination is not performed may be used.

In other words, as shown in FIG. 5, when the second vehicle speed in step S4 is less than the second threshold value (step S4 → No), the steering control ECU130 advances the procedure to step S6, the pinion torque _{T P} is the reference torque value or greater (step S6 → Yes), and, when the rotation direction of the direction and the pinion shaft 7 of the pinion torque _{T P} match (step S7 → Yes), may be configured to start the EPS10 (see FIG. 2).
The flowchart shown in FIG. 5 is obtained by deleting step S5 from the flowchart shown in FIG. 2, and the processing in each step is equivalent to the flowchart shown in FIG.
If comprised in this way, even if all the above-mentioned conditions 1-3 are not satisfy | filled, when the above-mentioned conditions 4 and 5 are satisfy | filled, EPS10 will be started regardless of the presence or absence of abnormality of CAN130a.

Also, if all the conditions 1 to 3 is not satisfied (step S4 → No), it starts when the pinion torque _{T P} is equal to or greater than the reference torque value (step S6 → Yes) in EPS10 (see FIG. 2) (Step S9) it may have a configuration, when the rotation direction of the direction and the pinion shaft 7 of the pinion torque T _P (see FIG. 2) matches start EPS10 (step S7 → Yes) even (step S9) constituting Good.
If comprised in this way, even if it is a case where all the conditions 1-3 are not satisfy | filled, steering control ECU130 (refer FIG. 1) can start EPS10 easily, and can prevent the fall of steering feeling.

  In addition, although it was set as the structure provided with CAN130a (refer FIG. 3) as an information communication means, an information communication means is not limited to CAN130a, For example, the information communication means which uses protocols, such as FlexRay, may be used. .

1 Vehicle 3 Steering handle (steering mechanism)
3a Main steering shaft (steering mechanism)
3b Universal joint (steering mechanism)
3c Shaft (steering mechanism)
4 Electric motor 5 Reduction mechanism (steering mechanism)
7 Pinion shaft (steering mechanism, rotating shaft)
8 Rack shaft (steering mechanism)
9 Tie rod (steering mechanism)
10 EPS (Electric Power Steering Device)
DESCRIPTION OF SYMBOLS 11 Vehicle drive unit 11a Engine 11b Traveling motor 23 Electric motor drive circuit (drive device)
130 Steering control ECU (control device)
130a CAN (information communication means)
ES complete explosion information (information indicating the status of the vehicle drive unit)
MS travel motor movement information (information indicating the state of the vehicle drive unit)
TS torque signal (signal indicating the magnitude and direction of steering torque)
TRS vehicle speed calculation value information (information indicating vehicle behavior)
VS vehicle speed information (information indicating vehicle behavior)
θS Angle signal (Signal indicating the amount and direction of rotation of the pinion shaft)

Claims (5)

An electric motor for providing a steering assist force to the steering mechanism;
A driving device for driving the electric motor;
A control device for controlling the drive device,
The control device starts the drive device based on information acquired through information communication means,
An electric power steering apparatus, wherein when the abnormality occurs in the information communication means, the drive device is started based on a signal input via a signal line different from that of the information communication means.   The information acquired by the control device via the information communication unit is at least one of information indicating the behavior of the vehicle and information indicating the state of the vehicle drive unit. Electric power steering device.   The signal input to the control device via the signal line includes a signal indicating the magnitude and direction of the steering torque and a signal indicating the rotation amount and rotation direction of the rotating shaft to which the steering torque is input in the steering mechanism. The electric power steering apparatus according to claim 1, wherein the electric power steering apparatus is at least one of the following. When an abnormality has occurred in the information communication means,
The electric power steering device according to claim 3, wherein the control device starts the driving device when a direction of the steering torque coincides with a rotation direction of the rotation shaft.   5. The electric power steering apparatus according to claim 1, wherein the information communication unit uses a CAN.

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