JP2003319683A - Motor-driven power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor-driven power steering device capable of resolving a problem resulting from the installation of two control means, such as microcomputers, for controlling a brushless motor by the division of labor. <P>SOLUTION: This power steering device is an electric power steering device provided with a target current signal setting means ( a control microcomputer) 40 for setting a target current signal IMS, a drive control means (a drive control microcomputer) 50 for setting a motor control signal VO, and a motor drive means (a motor drive circuit) 51 for driving a brushless motor 6. This power steering device connects a storage device (EEPROM) 43 to either of a target current signal setting means 40 or a drive control means 50, and transmits data which are stored in a storage device 43 from one of the means 40 (or 50) to the other means 50 (or 40), and/or the target current signal setting means 40 starts to transmit data to the drive control means 50 after receiving a stand-by signal transmitted from the drive control means 50. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric power steering device for reducing the steering force of a driver by directly applying electric motor power from a brushless motor to a steering system.

[0002]

2. Description of the Related Art Generally, an electric power steering apparatus uses a DC brush motor as an electric motor.
However, in the case of a DC brush motor, there is a problem such as abrasion of the brush due to aging, so an electric power steering system using a brushless motor as an electric motor has been developed. The brushless motor is provided with a three-phase winding as an outer stator and a plurality of permanent magnets as an inner rotor. Then, in the brushless motor, when the three-phase winding is energized based on the rotation phase of the inner rotor, the inner rotor is rotationally driven. Therefore, since the brushless motor does not need a brush, the steering feeling is not deteriorated due to the abrasion of the brush. In addition, the brushless motor is
Since the inner rotor is composed of magnets, the inertial moment is small and the steering feeling is not deteriorated due to the large inertial moment.

In an electric power steering apparatus using a brushless motor, an FET [Field Effect Transistor] forming a motor drive circuit for driving the brushless motor is used.
In order to drive or turn off the PWM [Pulse Width Modulation], the motor control signal is output to the motor drive circuit. Therefore, in the electric power steering device,
The auxiliary steering force generated by the brushless motor (ie,
In order to determine the target current to flow to the brushless motor)
The target current signal is set based on the steering torque signal from the steering torque detecting means, and the target current signal is corrected by inertia control or damper control.
Further, in the electric power steering apparatus, in order to flow the target current to the brushless motor, the deviation between the target current signal and the motor current signal from the motor current detection means (current actually flowing in the brushless motor) and the motor phase detection means. The electric motor control signal is set by the feedback control based on the electric motor phase signal (actual rotation phase of the inner rotor of the brushless motor) from. And
In the electric power steering device, the FET is PWM-driven in the electric motor drive circuit based on the electric motor control signal,
The brushless motor is rotating in the forward or reverse direction.

However, in the electric motor drive circuit, since a current of about several tens of amperes flows through the FET, heat is generated in the FET. Further, when driving the brushless motor, it is necessary to accurately control energization based on the actual rotation phase of the inner rotor. Therefore, an electric power steering device using a brushless motor has a configuration in which control is divided by two microcomputers (hereinafter, referred to as microcomputers) that are relatively inexpensive and simple. In other words, since the control device having the microcomputer that mainly sets the target current signal is arranged at a position separated from the electric motor drive circuit, the analog circuit for shaping the steering torque signal is not affected by heat. The target current can be set with high accuracy. On the other hand, since the drive control device mainly having the microcomputer for setting the electric motor control signal is arranged in the vicinity of the brushless motor and the electric motor phase detecting means, the electric motor phase signal transmission path is short, there is little noise and there is no phase delay. It is possible to accurately control energization of the brushless motor based on the motor phase signal. The control device (microcomputer) and the drive control device (microcomputer) are electrically connected to each other via a communication line, and exchange signals with each other. For example, the controller sends a target current signal or the like, while the drive controller sends a motor phase signal or the like used for damper control.

[0005]

However, the microcomputer of the control device requires data such as the center value of the steering torque, while the microcomputer of the drive control device requires data such as the offset value of the motor encoder. Therefore, the data necessary for each microcomputer is two EEPROM
M [Electrically Erasable Programmble Read Only Mem
ory], and is read from each EEPROM into each microcomputer for use. Therefore, the electric power steering device that controls the drive of the brushless motor by the two microcomputers is EEPRO for the two microcomputers.
Since each M is required, the cost becomes high.

Further, signals are transmitted and received between the two microcomputers by a clock synchronous method in order to perform high speed communication. In this clock-synchronized communication, the master microcomputer (control device microcomputer) transmits data based on the clock generated in the microcomputer, and the slave microcomputer (drive control device microcomputer) transmits the clock from the master microcomputer. Receiving data based on. Therefore, the slave microcomputer (microcomputer of the drive control device) continues to receive the data-shifted signal even if the received data has a shift even once. in this case,
Since the slave microcomputer (microcomputer of the drive control device) cannot obtain normal data (target current, etc.), control cannot be performed and a normal motor control signal cannot be set. As a result, the electric power steering device cannot apply the auxiliary steering force to the steering system.

For example, when the vehicle is started (the ignition switch is turned on), each part of the microcomputer of the drive control device is not electrically activated, or an initial check of the microcomputer (CPU [Central Processing Unit]) of the drive control device is performed. If the microcomputer of the control device starts the transmission of data when is not completed, the microcomputer of the drive control device is not in a state in which the data can be received, and thus a deviation occurs in the received data. Further, if noise is added to the communication line from the microcomputer of the control device to the microcomputer of the drive control device during communication, the data during communication will be deviated and the microcomputer of the drive control device will receive the signal with the deviated data. .

Therefore, an object of the present invention is to provide an electric power steering apparatus which solves the problems caused by having two control means (microcomputers or the like) for controlling a brushless motor by division of labor.

[0009]

An electric power steering apparatus according to claim 1 of the present invention, which has solved the above-mentioned problems, detects an electric motor for applying an auxiliary steering force to a steering system and a steering torque acting on the steering system. Steering torque detecting means for outputting a steering torque signal, electric motor phase detecting means for detecting a rotation phase of the electric motor and outputting an electric motor phase signal, and electric motor current flowing through the electric motor, and outputting an electric motor current signal A motor current detection means, a target current setting means for setting a target current signal based on at least the steering torque signal, a deviation between the target current signal and the motor current signal, and a motor control signal based on the motor phase signal. Drive control means for setting, and an electric motor drive means for driving the electric motor based on the electric motor control signal, The target current setting means and the drive control means are electrically connected by a communication line, and the electric motor is an electric power steering apparatus including a brushless motor, and either the target current setting means or the drive control means is provided. If a storage device is connected to one of the two, and the storage device is connected to the target current setting means, the data stored in the storage device is transferred from the target current setting means to the drive control means by the communication line. And the data stored in the storage device is transmitted from the drive control device to the target current setting device via the communication line when the storage device is connected to the drive control device. It is characterized by doing.

According to this electric power steering apparatus, data stored in a storage device (EEPROM or the like) is transmitted and received between the target current setting means and the drive control means, so that one storage device can be set with the target current setting. It is shared by the means and the drive control means. Therefore, in this electric power steering device, the storage device is not required for the target current setting means and the drive control means, so that the cost can be reduced.

An electric power steering system according to a second aspect of the present invention, which has solved the above-mentioned problems, detects a steering torque acting on an electric motor for applying an auxiliary steering force to a steering system and a steering torque signal. A steering torque detecting means for outputting, a motor phase detecting means for detecting a rotation phase of the electric motor, and outputting a motor phase signal,
A motor current detection unit that detects a motor current flowing in the motor and outputs a motor current signal, a target current setting unit that sets a target current signal based on at least the steering torque signal, the target current signal and the motor current. A drive control means for setting a motor control signal based on a deviation from a signal and the motor phase signal; and a motor drive means for driving the electric motor based on the motor control signal, the target current setting means and the The drive control unit is electrically connected by a communication line, and the electric motor is an electric power steering device including a brushless motor, and the drive control unit sends a standby signal indicating a state in which data can be received to the target. The target current setting means transmits the current to the current setting means, and the target current setting means receives the standby signal, Characterized in that it starts to send data to the control unit.

According to this electric power steering apparatus, the drive control means transmits a standby signal when the vehicle is ready to receive data at the time of starting the vehicle or when a communication error occurs during communication, and the target current setting means. Then, after receiving the standby signal, data transmission to the drive control means is started. Therefore, in this electric power steering apparatus, the drive control means can reliably receive normal data when the vehicle is started, and can resume normal communication after transmitting the standby signal even if a communication error occurs during communication. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an electric power steering apparatus according to the present invention will be described below with reference to the drawings.

In order to reduce the cost, the electric power steering apparatus according to the present invention has a storage device (EEPROM) in one of the target current setting means (microcomputer etc.) for controlling the drive of the brushless motor and the drive control means (microcomputer etc.).
Etc.), and the data stored in the storage device is transmitted from one means to which the storage device is connected to the other means to which the storage device is not connected. Further, the electric power steering apparatus according to the present invention transmits a standby signal from the drive control means to the target current setting means so that the drive control means normally receives the data transmitted from the target current setting means, thereby setting the target current setting means. The means is configured to transmit the data to the drive control means after receiving the standby signal.

In the electric power steering apparatus according to the present embodiment, the control device for setting the target current supplied to the brushless motor and the drive device for driving the brushless motor based on the target current are separately arranged. Was set up,
The control device and the drive device are connected by a wire harness. The control device according to the present embodiment includes a one-chip control microcomputer for performing various calculations and an EEPROM for storing various data, and is arranged along the pinion axis. On the other hand, the drive device according to the present embodiment includes a one-chip drive control microcomputer for performing various calculations and an electric motor drive circuit, and is arranged adjacent to the brushless motor. In this embodiment,
The control microcomputer and the drive control microcomputer communicate with each other by a clock synchronous method.

First, the overall configuration of the electric power steering apparatus 1 will be described with reference to FIG. FIG. 1 is an overall configuration diagram of an electric power steering device.

The electric power steering apparatus 1 is provided in the steering system S from the steering wheel 3 to the steered wheels W, W and assists the steering force by the manual steering force generation means 2. Therefore, the electric power steering apparatus 1 causes the drive device 5 to generate the electric motor voltage VM based on the target current signal IMS from the control device 4, and drives the brushless motor 6 by the electric motor voltage VM to generate an auxiliary torque (auxiliary steering). Force) to reduce the manual steering force by the manual steering force generation means 2. In the present embodiment,
The brushless motor 6 corresponds to the electric motor described in the claims.

The manual steering force generating means 2 includes a pinion shaft 7 of a rack and pinion mechanism 7 via a connecting shaft 2b to a steering shaft 2a provided integrally with a steering wheel 3.
a is connected. The connecting shaft 2b is provided with universal joints 2c and 2d at both ends thereof. In the rack and pinion mechanism 7, rack teeth 7d that mesh with the pinion 7b at the tip of the pinion shaft 7a are formed on the rack shaft 7c, and by the meshing of the pinion 7b and the rack teeth 7d, the pinion shaft 7a
Is a reciprocating motion of the rack shaft 7c in the lateral direction (vehicle width direction). Further, the rack shaft 7c has
Left and right front wheels W, W as steered wheels are connected to both ends thereof via ball joints 8, 8 and tie rods 9, 9.

Further, the electric power steering device 1 is
A brushless motor 6 is provided to generate the auxiliary torque. The brushless motor 6 causes the auxiliary torque to act on the pinion shaft 7 a via the torque limiter 10 and the gear type speed reduction mechanism 11.

That is, the electric power steering device 1
Transmits the steering torque applied by the driver to the steering wheel 3 to the pinion shaft 7a and the auxiliary torque generated by the brushless motor 6 according to the steering torque to the pinion shaft 7a, and the rack and pinion mechanism 7 operates the steering wheel. This is a device for steering the wheels W, W.

In the electric power steering apparatus 1, a rack shaft 7c is provided in a housing (not shown) extending in the vehicle width direction.
Is stored so as to be slidable in the longitudinal direction of the shaft. Further, the housing accommodates the rack and pinion mechanism 7, the torque limiter 10, and the gear type speed reduction mechanism 11. The upper opening of the housing is closed by a lid (not shown), the pinion shaft 7a is inserted through the center of the lid, and the steering torque sensor TS is attached inside. Further, a storage case (not shown) for storing the control device 4 is attached to the outer peripheral surface of the lid, and the control device 4 is arranged.

The side opening of the housing is closed by another lid (not shown), and a motor case (not shown) is attached to the opposite side of the lid from the housing. The brushless motor 6 is housed in the motor case, and the motor rotation detection means 13 is housed at one end of the brushless motor 6. A storage case (not shown) for storing the drive device 5 is attached to the outer peripheral surface of the motor case. Therefore, the drive device 5 is arranged adjacent to the brushless motor 6 and the electric motor rotation detection means 13.

A torque limiter 10 is housed inside the side opening of the housing. The torque limiter 10 includes a female taper inner member (not shown) that is serration-coupled to a motor shaft (not shown) of the brushless motor 6 and a worm shaft (not shown) of the gear type reduction mechanism 11 that is serrated. Taper shape (cup shape)
Is a torque limiting mechanism fitted to an outer member (not shown) of. When a large torque exceeding a predetermined frictional force is applied to the torque limiter 10, the outer peripheral surface of the inner member and the inner peripheral surface of the outer member slip. Therefore, it is possible to limit the auxiliary torque transmitted from the brushless motor 6 to the gear type speed reduction mechanism 11 and cut over torque. Therefore, the excessive torque is not generated in the brushless motor 6, and the excessive torque is not transmitted to the downstream side of the torque limiter 10.

Further, a gear type speed reducing mechanism 11 is housed in the housing. The gear type speed reduction mechanism 11 applies the auxiliary torque generated by the brushless motor 6 to the pinion shaft 7
It is a torque transmitting means for transmitting to a and is composed of a worm gear mechanism. The gear type speed reduction mechanism 11 includes a brushless motor 6
Worm shaft (not shown) connected to a motor shaft (not shown) of the worm via a torque limiter 10, a worm gear (not shown) formed on the worm shaft, and a worm wheel (not shown) connected to the pinion shaft 7a. No)).

The control device 4 receives the detection signals V and T of the vehicle speed sensor VS and the steering torque sensor TS, respectively. Then, the control device 4 calculates a target current signal IMS as a target current to be supplied to the brushless motor 6 based on these detection signals V and T, and outputs this target current signal IMS to the drive device 5. The control device 4 is electrically connected to the drive device 5 by the wire harness WH. The wire harness WH includes a clock communication line CW, a data transmission communication line TW, a data reception communication line RW, a standby signal communication line SW, etc. (see FIG. 2). In addition,
In the present embodiment, the steering torque sensor TS corresponds to the steering torque detecting means described in the claims, and includes the clock communication line CW, the data transmission communication line TW, the data reception communication line RW, and the standby signal communication. The line SW or the like corresponds to the communication line described in the claims.

The drive unit 5 includes a motor current detecting means 12,
The detection signals IMO and PMO of the motor rotation detection means 13 are input. Then, the drive unit 5 uses the drive control microcomputer 50 to set the target current signal IMS and the detection signals IM of these.
The motor control signal VO is generated based on O and PMO, and the motor drive circuit 51 applies the motor voltage VM to the brushless motor 6 based on the motor control signal VO (see FIG. 2). Further, the drive device 5 is directly connected to the battery BT via the fuse FS and the fuse FS,
It is connected via the FS and the ignition switch IG, and a battery power (12V) is supplied. Then, the driving device 5 generates a constant voltage (5V) by the battery power source (12V), and also supplies this constant voltage to the control device 4. In the present embodiment, the electric motor rotation detecting means 13 corresponds to the electric motor phase detecting means described in the claims, and the electric motor drive circuit 51 corresponds to the electric motor driving means described in the claims.

The vehicle speed sensor VS is a sensor that detects the vehicle speed as the number of pulses per unit time, and transmits a pulse signal corresponding to the detected number of pulses to the control device 4 as a vehicle speed signal V. The vehicle speed sensor VS may be a dedicated sensor for the electric power steering device 1, or
Vehicle speed sensors of other systems may be used.

The steering torque sensor TS is a pinion shaft 7a.
This is a magnetostrictive torque sensor that electromagnetically detects the magnetostrictive effect generated according to the torque applied to the electric coil by an electric coil, and detects the magnitude and direction of the manual steering torque by the driver. Then, the steering torque sensor TS is
An analog electric signal corresponding to the detected steering torque is transmitted to the control device 4 as a steering torque signal T. In addition,
The steering torque signal T includes information on the steering torque indicating the magnitude and the torque direction indicating the direction of the torque.

The electric motor current detecting means 12 is provided with a resistor or a Hall element connected in series to the brushless motor 6, and detects the electric motor current IM actually flowing in the brushless motor 6. Then, the electric motor current detection means 1
2 is a motor current signal IMO corresponding to the motor current IM
Is fed back (negative feedback) to the driving device 5. The electric motor current signal IMO is a three-phase AC signal, and the electric motor current value indicating the magnitude of the current actually flowing through the windings of each phase of the brushless motor 6 and the three-phase winding of the brushless motor 6 It includes information on the winding of the phase in which the motor current is flowing.

The electric motor rotation detecting means 13 is a resolver which is arranged at one end of the brushless motor 6 and detects an electric motor rotation angle PM of an inner rotor (not shown) of the brushless motor 6. For that purpose, the electric motor rotation detection means 13 includes a motor shaft (not shown) of the brushless motor 6.
Laminated core rotor (not shown) attached to one end of
And a detection element (a combination of an excitation coil and a detection coil) (not shown) for magnetically detecting the rotation angle of the laminated core rotor. Then, the motor rotation detection means 13
Is the motor rotation signal PM corresponding to the motor rotation angle PM.
O is transmitted to the driving device 5. The electric motor rotation signal PMO includes information such as a rotation direction and a rotation angle of an inner rotor (not shown) of the brushless motor 6, and is composed of two excitation signals, two cosine signals and two sine signals.

The configuration of the control device 4 will be described with reference to FIG. FIG. 2 is a block diagram of the control device and the drive device.

The control device 4 is electrically connected to the drive device 5 by a wire harness WH, and communicates various signals via the wire harness WH (see FIG. 1).
The control device 4 includes a one-chip control microcomputer 40 and a torque sensor I / F circuit 4 included in the control microcomputer 40.
1, a vehicle speed sensor I / F circuit 42, an output circuit (not shown) for various signals, an EEPROM 43 for storing various data used by the control microcomputer 40, a watchdog timer (not shown), etc. There is. In addition,
In the present embodiment, the control microcomputer 40 corresponds to the target current setting means described in the claims, and the EEPROM
Corresponds to the storage device described in the claims.

Then, the control device 4 takes in various detection signals T, V from the vehicle and the electric motor rotation speed signal SMO from the drive device 5, and based on the taken-in signals T, V, SMO, a target current to be passed to the brushless motor 6 is obtained. Set.

Further, the control device 4 monitors the operation of the control microcomputer 40 by means of the watchdog timer, monitors the operation itself, and at the same time detects an abnormality (failure) in the operation of the control microcomputer 40 by means of the watchdog timer. When detected, a failure signal is transmitted to the drive device 5 (drive control microcomputer 50). Further, the control device 4 mutually monitors the operation of the drive control microcomputer 50 by transmitting a watchdog pulse to the drive control microcomputer 50 and confirming that the pulse is returned from the drive control microcomputer 50. ing.

Before describing the control configuration of the control microcomputer 40, the torque sensor I / F circuit 41 and the vehicle speed sensor I will be described.
The / F circuit 42 and the EEPROM 43 will be described.

The torque sensor I / F circuit 41 has a steering torque signal T (analog signal) from the steering torque sensor TS.
Is input, and a steering torque signal T (digital signal) is output to the target current setting unit 40a and the inertia control unit 40d. The torque sensor I / F circuit 41 converts the steering torque signal T, which is an analog signal, into a digital signal.

The vehicle speed sensor I / F circuit 42 receives the vehicle speed signal V (pulse signal) from the vehicle speed sensor VS and outputs the vehicle speed signal V (digital signal) to the target current setting unit 40a and the inertia control unit 40d. Vehicle speed sensor I /
The F circuit 42 converts the vehicle speed signal V, which is a pulse signal, into a digital signal.

The EEPROM 43 is a control microcomputer 40.
And a drive control microcomputer 50 are shared, and can be rewritten by an electrical operation. EEPR
In the OM 43, the center value of the steering torque used in the control microcomputer 40, various maps for setting the target current signal IMS, the failure history of the control microcomputer 40, and the offset of the motor encoder used in the drive control microcomputer 50. Values, a failure history of the drive control microcomputer 50, and the like are stored. By the way, the data stored in the EEPROM 43 can be rewritten at a vehicle production plant, a dealer, or the like.

The control configuration of the control microcomputer 40 will be described. The control microcomputer 40 includes a target current setting unit 40a and a damper control unit 4 for setting the target current signal IMS.
0b, a damper correction unit 40c, an inertia control unit 40d, an inertia correction unit 40e, and a clock generation unit 40f and a standby signal reception unit 40g. Then, in the control microcomputer 40, the processing in each of the units 40a to 40e for setting the target current signal IMS is repeatedly executed every basic processing time (for control) based on the clock generated by the clock generation unit 40f. .

The target current setting section 40a will be described.
The target current setting unit 40a includes a torque sensor I / F circuit 41
The steering torque signal T (digital signal) from the vehicle speed sensor I / F circuit 42 and the vehicle speed signal V (digital signal) from the vehicle speed sensor I / F circuit 42 are input to the damper correction unit 40c.
Output MS. The target current setting unit 40a addresses the steering torque signal T and the vehicle speed signal V based on the corresponding maps of the steering torque signal T and the vehicle speed signal V and the target current signal IMS which are set in advance based on the experimental value or the design value. The corresponding target current signal IMS is read as.
The target current signal IMS is a signal including information on a current that serves as a reference when setting a target electric motor current to be passed through the brushless motor 6. By the way, the target current signal IMS is
A large value is associated with the vehicle speed signal V when the road surface reaction force is large at a low speed, and a small value is associated with the vehicle speed signal V at a high speed to ensure stability during traveling. Further, the target current signal IMS is associated with 0 in the vicinity of the steering torque signal T with respect to the steering torque signal T,
When the steering torque signal T exceeds a predetermined value, the steering torque signal T
It is associated with a value that increases with an increase in. The target current signal IMS is set to be equal to or less than the maximum target current because the maximum current that can be passed through the brushless motor 6 is specified.

The damper control section 40b will be described. The damper control unit 40b receives the electric motor rotation speed signal SMO transmitted from the drive control microcomputer 50 and outputs a damper control signal to the damper correction unit 40c. The damper control unit 40b reads a corresponding damper control signal by using the electric motor rotation speed signal SMO as an address, based on the corresponding data of the electric motor rotation speed signal SMO and the damper control signal set in advance based on an experimental value or a design value. . The damper control signal is used to reduce the motor rotation speed signal S in order to attenuate the excessive effect of the assist and improve the steering feeling.
A larger value is associated with MO as the motor rotation speed signal SMO is larger. The damper control unit 40b
Then, the vehicle speed signal V (digital signal) from the vehicle speed sensor I / F circuit 42 may be input, and the damper control signal may be set in consideration of the vehicle speed signal V.

The damper corrector 40c will be described. The damper correction unit 40c receives the target current signal IMS from the target current setting unit 40a and the damper control signal from the damper control unit 40b, and outputs the target current signal IMS (after damper correction) to the inertia correction unit 40e. By the way,
In the damper control by the damper control unit 40b and the damper correction unit 40c, a large electric motor current IM is applied to the brushless motor 6.
Is attenuated, the excessive effect of the assist due to the inertia of the rotating portion of the brushless motor 6 is attenuated, and the steering feeling is improved. That is, when the brushless motor 6 is supplied with a large electric motor current IM and the rotation speed increases,
Due to the inertia, the rotation speed does not immediately decrease. Therefore, in the damper control, the rotational speed of the brushless motor 6 is controlled to be suppressed. Therefore, the damper control attenuates the target current signal IMS by the damper control signal. Therefore,
The damper correction unit 40c subtracts the damper control signal from the target current signal IMS to calculate the target current signal IMS (after damper correction).

The inertia control section 40d will be described. The inertia control unit 40d receives the steering torque signal T (digital signal) from the torque sensor I / F circuit 41 and the vehicle speed signal V (digital signal) from the vehicle speed sensor I / F circuit 42, and the inertia correction unit 40e receives the inertia signal. Output a control signal. First, the inertia control unit 4
At 0d, the steering torque signal T is time-differentiated to calculate the time derivative of the steering torque. Then, the inertia control unit 4
At 0d, the time differential value of the steering torque and the vehicle speed signal V are set as addresses based on the time differential value of the steering torque and the corresponding data of the vehicle speed signal V and the inertia control signal, which are set in advance based on an experimental value or a design value. Read the corresponding inertia control signal. Further, the inertia control signal is associated with a larger value as the time differential value is larger in order to improve the responsiveness to the steering operation by the driver with respect to the time differential value of the steering torque.

The inertia correction section 40e will be described. The inertia correction unit 40e receives the target current signal IMS (after the damper correction) from the damper correction unit 40c and the inertia control signal from the inertia control unit 40d, and inputs the target current signal IMS (after the damper correction and the target current signal IMS to the drive control microcomputer 50). Send (after inertia correction). By the way, the inertia control unit 40d and the inertia correction unit 40e
In the inertia control by, the response deterioration due to the inertia of the rotating portion of the brushless motor 6 is improved, and the steering feeling is improved. That is, the brushless motor 6 is
When switching the rotation direction from the forward rotation to the reverse rotation or from the reverse rotation to the forward rotation, even if the direction in which the electric motor voltage VM is applied is changed, the rotation direction is not immediately switched due to the inertia. Therefore, in inertia control, the brushless motor 6
Is controlled so that the rotation direction of the steering wheel 3 changes at the same timing as the rotation direction of the steering wheel 3. Therefore, the inertia control increases the target current signal IMS by the inertia control signal in order to cancel the inertia of the brushless motor 6. Therefore, the inertia correction unit 40e adds the inertia control signal to the target current signal IMS (after the damper correction) to obtain the target current signal IM.
S (after damper correction and after inertia correction) is calculated.

The clock generator 40f will be described.
The clock generator 40f generates a basic clock for the control microcomputer 40. Control microcomputer 40
In, the basic processing time (for control) is generated based on the clock generated by the clock generation unit 40f. In addition, the control microcomputer 40 performs clock-synchronous communication with the drive control microcomputer 50 based on the clock generated by the clock generation unit 40f, and transmits data via the data transmission communication line TW. In addition, the data is received through the data receiving communication line RW. Therefore, the control microcomputer 40 transmits the generated clock to the drive control microcomputer 50 via the clock communication line CW.

The standby signal receiving section 40g will be described. The standby signal receiving unit 40g allows the drive control microcomputer 50 to receive the transmitted data normally.
It manages the start point of data transmission. Therefore, the standby signal receiving unit 40g receives the standby signal transmitted from the drive control microcomputer 50 via the standby signal communication line SW and monitors the HI signal / LO signal of the standby signal. That is, when the standby signal is the HI signal, the standby signal receiving unit 40g determines that the drive control microcomputer 50 can receive the data, and permits the data transmission to the drive control microcomputer 50. On the other hand, in the standby signal receiving unit 40g, when the standby signal is the LO signal, the drive control microcomputer 50 determines that the data cannot be received, and prohibits the data transmission to the drive control microcomputer 50.

Specifically, the ignition switch IG
Is turned on (see FIG. 1), the standby signal receiving unit 4
At 0 g, when it is detected that the standby signal has switched from the LO signal to the HI signal, data transmission is permitted.
At this time, the control microcomputer 40 stops transmitting data to the drive control microcomputer 50 until the permission is obtained,
When permission is given, data transmission starts. Further, after the transmission to the drive control microcomputer 50 is started after the ignition switch IG is turned on, the standby signal receiving unit 4
At 0g, when it is detected that the standby signal has switched from the HI signal to the LO signal, data transmission is prohibited.
At this time, the control microcomputer 40 temporarily stops transmitting data to the drive control microcomputer 50. Then, in the standby signal receiving unit 40g, the standby signal becomes LO.
When it is detected that the signal has been switched to the HI signal, data transmission is permitted. At this time, the control microcomputer 40 again starts transmitting data to the drive control microcomputer 50.

In particular, when the ignition switch IG is turned on, the control microcomputer 40 has an EEPROM.
The data stored in 43 is read, and the data used by the drive control microcomputer 50 out of the read data is transmitted to the drive control microcomputer 50.

The structure of the drive unit 5 will be described with reference to FIG.

The drive unit 5 is electrically connected to the control unit 4 by a wire harness WH, and communicates various signals via the wire harness WH (see FIG. 1).
The drive device 5 includes a one-chip drive control microcomputer 50, a motor drive circuit 51, a motor current I / F circuit 52, and an R / D.
The conversion circuit 53, an output circuit (not shown) for various signals, a watchdog timer (not shown) and the like are included. In the present embodiment, the drive control microcomputer 50 is used.
Corresponds to the drive control means described in the claims.

Then, the drive unit 5 takes in the various detection signals IMO, PMO from the vehicle and the target current signal IMS (after the damper correction and the inertia correction) from the control unit 4, and based on the taken in signals IMO, PMO, IMS. The electric motor control signal VO is set, and the brushless motor 6 is energized to drive it.

Further, the drive unit 5 monitors the operation of the drive control microcomputer 50 by means of the watchdog timer, performs self-monitoring of the operation, and at the same time, makes an abnormality (failure) in the operation of the drive control microcomputer 50 by the watchdog timer. ) Is detected, the control device 4 (control microcomputer 4
Send a failure signal to 0). Further, the driving device 5 mutually monitors the operation of the control microcomputer 40 by transmitting a watchdog pulse to the control microcomputer 40 and confirming that the pulse is returned from the control microcomputer 40.

Before explaining the drive control microcomputer 50,
The motor current I / F circuit 52 and the R / D conversion circuit 53 will be described.

The motor current I / F circuit 52 receives the motor current signal IMO (analog signal) from the motor current detection means 12 and outputs the motor current signal IMO (digital signal) to the drive control microcomputer 50. The motor current I / F circuit 52 converts the analog motor signal IMO into a digital signal.

The R / D conversion circuit 53 receives the motor rotation signal PMO (analog signal) from the motor rotation detection means 13, and the drive control microcomputer 50 receives the motor rotation signal PMO.
MO (digital signal) is output. R / D conversion circuit 5
In 3, the rotation direction and the rotation angle are calculated from the electric motor rotation signal PMO which is an analog signal and converted into the electric motor rotation signal PMO which is a digital signal.

The drive control microcomputer 50 will be described. The drive control microcomputer 50 uses the current converter 50a and the rotation angle converter 50 to set the motor control signal VO.
b, torque deviation calculator 50c, magnetic field deviation calculator 50
d, torque PI control unit 50e, magnetic field PI control unit 50
f, a voltage converter 50g, a PWM converter 50h, and a clock generator 50i and a standby signal transmitter 50j. Then, in the drive control microcomputer 50, each unit 5 for setting the electric motor control signal VO based on the clock generated by the clock generation unit 50i.
The processing from 0a to 50h is repeatedly executed every basic processing time (for drive control).

The current converter 50a will be described. The current converter 50a receives the motor current signal IMO (digital signal) from the motor current I / F circuit 52 and the motor rotation phase signal from the rotation angle converter 50b, and the torque deviation calculator 50c receives the torque control current. A magnetic field control current signal is output to the signal and magnetic field deviation calculator 50d.
In the current converter 50a, the current component for generating the rotational torque of the brushless motor 6 is extracted from the electric motor current on the basis of the electric motor current signal IMO that is a three-phase alternating current, the electric motor rotation phase signal, etc. The magnetic field control current signal is set by extracting the current component that is generating the magnetic field of the brushless motor 6 while setting.

The rotation angle converter 50b will be described. The rotation angle conversion unit 50b receives the motor rotation signal PMO (digital signal) from the R / D conversion circuit 53, outputs a motor rotation phase signal to the current conversion unit 50a and the voltage conversion unit 50g, and outputs it to the control microcomputer 40. The electric motor rotation speed signal SMO is transmitted. In the rotation angle conversion unit 50b,
The rotation speed of the brushless motor 6 is calculated based on the rotation angle and rotation direction of the electric motor rotation signal PMO, and the electric motor rotation speed signal SMO is set. Further, the rotation angle conversion unit 50b calculates an accurate rotation phase in consideration of the lead angle based on the rotation angle, the rotation direction, and the rotation speed of the motor rotation signal PMO, and sets the motor rotation phase signal.

The torque deviation calculator 50c will be described. The torque deviation calculation unit 50c includes the control microcomputer 40.
The target current signal IMS (after the damper correction and after the inertia correction) transmitted from the vehicle and the torque control current signal from the current conversion unit 50a are input, and the torque PI control unit 50 is input.
The deviation signal for torque control is output to e. The torque deviation calculation unit 50c subtracts the torque control current signal from the target current signal IMS to set the torque control deviation signal.

The magnetic field deviation calculator 50d will be described. The magnetic field deviation calculation unit 50d receives the magnetic field control current signal from the current conversion unit 50a, and receives the magnetic field PI control unit 5d.
The deviation signal for magnetic field control is output to 0f. The magnetic field deviation calculator 50d subtracts the magnetic field control current signal from 0 to set the magnetic field control deviation signal.

The torque PI controller 50e will be described. The torque PI control unit 50e receives the torque control deviation signal from the torque deviation calculation unit 50c and outputs the torque PI control signal (DC voltage component) to the voltage conversion unit 50g. The torque PI control unit 50e performs P (proportional) and I (integral) control on the torque control deviation signal,
In order to bring the torque control deviation close to 0, a motor voltage (DC component) applied to the brushless motor 6 and a torque PI control signal indicating the rotation direction of the brushless motor 6 are set.

The magnetic field PI controller 50f will be described. The magnetic field PI control unit 50f includes a magnetic field deviation calculation unit 50.
The magnetic field control deviation signal from d is input, and the voltage conversion unit 5
The PI control signal for magnetic field (DC voltage component) is output to 0 g. The magnetic field PI control unit 50f performs P (proportional) and I (integral) control on the magnetic field control deviation signal, and applies a motor voltage (DC component) to the brushless motor 6 to bring the magnetic field control deviation close to zero. And a magnetic field PI control signal indicating the rotation direction of the brushless motor 6.

The voltage converter 50g will be described. The voltage conversion unit 50g uses the motor rotation phase signal from the rotation angle conversion unit 50b and the torque P control signal from the torque PI control unit 50e.
I control signal (DC voltage component) and magnetic field PI control unit 5
The PI control signal for magnetic field (DC voltage component) from 0f is input, and the PI control signal (three-phase AC voltage component) is output to the PWM conversion unit 50h. The voltage converter 50g determines the winding of the phase to which the motor voltage is applied among the three-phase (U-phase, V-phase, W-phase) winding based on the motor rotation phase signal. Then, the voltage conversion unit 50g sets a PI control signal including a U-phase voltage, a V-phase voltage, and a W-phase voltage, which are three-phase AC components, based on the torque PI control signal and the magnetic field PI control signal.

The PWM converter 50h will be described. P
The WM conversion unit 50h receives the PI control signal (three-phase AC voltage component) from the voltage conversion unit 50g and outputs the electric motor control signal VO to the electric motor drive circuit 51. PWM converter 5
At 0h, the brushless motor 6 is driven based on the PI control signal.
Value of the motor current IM supplied to each phase and each phase (U phase, V
PWM signal or OFF signal corresponding to each phase, W phase) is generated for each of the FETs 51a to 51f of the motor drive circuit 51. That is, in the PWM conversion unit 50h, the PW is calculated based on the PI control signal including the information of the winding of the phase to which the voltage is applied.
The FETs 51a to 51f that are targets for generating the M signal are determined, and the duty ratio of the PWM signal is set based on the information of the U-phase voltage, the V-phase voltage, and the W-phase voltage of the PI control signal.

By the way, the brushless motor 6 has a U-phase,
It consists of three-phase windings of V-phase and W-phase, and the motor voltage V
M (U-phase voltage VMU, V-phase voltage VMV, W-phase voltage VM
W) is applied to the terminals U ₀ , V ₀ , and W ₀ of each phase, and the three-phase winding is energized as a three-phase alternating current in the phase order, whereby the inner rotor (motor shaft) (not shown) rotates. Further, the brushless motor 6 is driven to rotate normally or reversely by being energized in the order of U-phase → V-phase → W-phase → U-phase or U-phase → W-phase → V-phase → U-phase. . Therefore, the PI control units 50e and 50f determine the direction in which the brushless motor 6 is rotated and the voltage of each phase based on each deviation signal, and the voltage conversion unit 50g determines the winding of the phase to be energized based on the motor rotation phase signal. ing.

The clock generator 50i will be described.
The clock generator 50i generates a basic clock for the drive control microcomputer 50. The drive control microcomputer 50 generates a basic processing time (for drive control) based on the clock generated by the clock generator 50i. The drive control microcomputer 50 performs clock synchronous communication with the control microcomputer 40 based on the clock transmitted from the control microcomputer 40.
The data is received via the data transmission communication line TW, and the data is transmitted via the data reception communication line RW.

The standby signal transmitter 50j will be described. The standby signal transmitter 50j transmits a standby signal to the control microcomputer 40 via the standby signal communication line SW in order to normally receive the data from the control microcomputer 40. The standby signal is composed of an HI signal and an LO signal, and the HI signal is set when the drive control microcomputer 50 can receive data normally or when the data is normally received. The LO signal is set when the data cannot be normally received or when the data is not normally received.

Specifically, the ignition switch IG
When is turned on (see FIG. 1), the standby signal transmitter 50j confirms whether or not the data from the control microcomputer 40 can be received by the drive control microcomputer 50, and if the data cannot be received normally. The LO signal is set as the standby signal, and the HI signal is set as the standby signal when it is confirmed that the signal can be received. Then, the standby signal transmitter 50j sets the HI signal as a standby signal when data is normally received. In addition, after starting the reception of data from the control microcomputer 40, the standby signal transmitter 5
At 0j, it is detected whether or not the data is normally received from the control microcomputer 40, and when the data is not normally received, the LO signal is set as the standby signal.
Then, when it is confirmed that the transmission of data from the control microcomputer 40 is temporarily stopped, the standby signal transmission unit 50j sets the HI signal as a standby signal. In the present embodiment, the standby signal of the HI signal corresponds to the standby signal indicating the state in which data described in the claims can be received.

In the confirmation of the receivable state in the drive control microcomputer 50, for example, the drive control microcomputer 50 is checked.
It is confirmed whether or not each part of (1) is electrically started up, whether the initial check of the CPU of the drive control microcomputer 50 is completed, and the like. By confirming such a fact when the ignition switch IG is turned on, data deviation does not occur at the start of reception. Further, in detecting whether or not data is normally received from the control microcomputer 40, for example, a sum check or a parity check is performed on the received data, or a check is made as to whether or not data is being received at regular intervals. I do. By performing such a check, it is possible to detect a data shift or the like. Therefore, even if a communication error occurs due to the influence of noise on the data transmission communication line TW, the error can be eliminated and normal reception can be resumed.

The electric motor drive circuit 51 will be described. The electric motor drive circuit 51 receives the electric motor control signal VO from the drive control microcomputer 50 and applies the electric motor voltage VM to the brushless motor 6. Therefore, the electric motor drive circuit 51 includes the FETs 51a, 51b, 51c, 51d, 51.
e and 51f form a bridge circuit, and the power supply voltage is 51g.
Is supplied with a voltage of 12V. Further, in the electric motor drive circuit 51, the U ₀ terminal of the brushless motor 6 is FET 51
The source Sa of a and the drain Db of the FET 51b are connected to each other, and the V ₀ terminal of the brushless motor 6 is an FET.
51c is connected to the connection terminal between the source Sc and the drain Dd of the FET 51d, and the W ₀ terminal of the brushless motor 6 is F
Source Se of ET51e and drain Df of FET51f
It is connected to the connection end with. FETs 51a to 51f
Is turned on when a PWM signal or an OFF signal is input to each of the gates Ga to Gf and the PWM signal is input and the logic level is 1. The electric motor voltage VM applied to the brushless motor 6 is an FET that is selectively PWM-driven.
Is determined by the duty ratio of the PWM signal.

Now, with reference to FIGS. 1 and 2, the operation of the control device 4 and the drive device 5 in the electric power steering device 1 will be described. Here, a case will be described in which when the ignition switch IG is turned on, a data shift occurs due to the influence of noise on the data transmission communication line TW while the drive control microcomputer 50 is receiving the data.

A case where the ignition switch IG is turned on will be described.

When the ignition switch IG is turned on, each electric circuit and the like of the control device 4 are activated and a constant voltage is supplied to the control microcomputer 40. Then,
In the control microcomputer 40, each unit is electrically activated and the CPU performs an initial check. After the initial check, the control microcomputer 40 receives the standby signal from the drive control microcomputer 50 via the standby signal communication line SW, monitors the HI signal / LO signal of the standby signal, and at the same time, transmits the clock communication line. C
The transmission of the internally generated clock is started via W. At this time, the control microcomputer 40 does not transmit data to the drive control microcomputer 50 until the standby signal switches from the LO signal to the HI signal. Further, the control microcomputer 40 reads the data stored in the EEPROM 43 into the internal RAM [Random Access Memory].

On the other hand, also in the drive unit 5, each electric circuit and the like are activated, and a constant voltage is supplied to the drive control microcomputer 50. Then, in the drive control microcomputer 50, each unit is electrically activated and the CPU performs an initial check. After the initial chucking, the drive control microcomputer 50 confirms whether or not the data from the control microcomputer 40 can be received, and outputs the LO signal as a standby signal to the control microcomputer 40 as a standby signal until the data can be received. When a receivable state is confirmed, the HI signal is transmitted as a standby signal to the control microcomputer 40 via the standby signal communication line SW.

When the control microcomputer 40 detects that the standby signal has switched from the LO signal to the HI signal, it starts transmitting data to the drive control microcomputer 50. First, in the control microcomputer 40, of the data stored in the EEPROM 43 that is read out to the RAM, the data used by the drive control microcomputer 50 is transmitted in a clock synchronous manner via the data transmission communication line TW.

Then, the drive control microcomputer 50 receives the data stored in the EEPROM 43 by the clock synchronous method based on the clock transmitted from the control microcomputer 40. At this time, since the drive control microcomputer 50 is in a state where each unit can receive data, data can be normally received. Then, the drive control microcomputer 50
Then, the received data stored in the EEPROM 43 is stored in the internal RAM.

Then, the control microcomputer 40 sets the steering torque signal T and the vehicle speed signal V for each basic processing time (for control).
Based on the steering torque signal T, the vehicle speed signal V, and the motor rotation speed signal SMO from the drive control microcomputer 50, and the target current signal IMS is corrected by damper control and inertia control. Give. Further, the control microcomputer 40 monitors the HI signal / LO signal of the standby signal. Incidentally, the control microcomputer 40 transmits the target current signal IMS (after damper correction and inertia correction) and the like to the drive control microcomputer 50 via the data transmission communication line TW in a clock synchronous manner, and at the same time, the motor rotation speed signal. SM
O and the like are received from the drive control microcomputer 50 via the data reception communication line RW in a clock synchronous manner.

On the other hand, in the drive control microcomputer 50, the target current signal IMS (after the damper correction and after the inertia correction) and the electric motor current signal I are performed every basic processing time (for the drive control).
MO (digital signal) and motor rotation signal PMO
The motor control signal VO is set based on the (digital signal). Further, the drive control microcomputer 50 detects whether or not the data is normally received from the control microcomputer 40, and while the data is normally received, a HI signal is standby as a standby signal to the control microcomputer 40. It is transmitted via the signal communication line SW. Incidentally, the drive control microcomputer 50 receives the target current signal IMS (after damper correction and after inertia correction) and the like from the control microcomputer 40 via the data transmission communication line TW in a clock synchronous manner, and at the same time, the motor rotation speed signal is received. The SMO and the like are transmitted to the control microcomputer 40 via the data receiving communication line RW in a clock synchronous manner.

Further, in the electric motor drive circuit 51, the FETs 51a, 51b, 51 corresponding to the electric motor control signal VO.
c, 51d, 51e, 51f are selectively PWM driven,
The motor voltage VM (U-phase voltage VMU, V-phase voltage VM) is applied to the U ₀ terminal, V ₀ terminal or W ₀ terminal of the brushless motor 6.
V, W phase voltage VMW) is applied. At this time, in the electric motor drive circuit 51, in order to drive the brushless motor 6 in the forward rotation direction (or the reverse rotation direction) according to the electric motor control signal VO, the FETs 51a, 51 selectively PWM-driven.
b, 51c, 51d, 51e, 51f are sequentially changed, and the voltage value of the applied motor voltage VM is also changed.

In the brushless motor 6, the U phase,
The motor voltage VM (U-phase voltage VMU, V-phase voltage VMV, W-phase voltage VMW) is applied to either the V-phase or W-phase winding, and the motor current IM (U-phase current IMU, V-phase current IM
V and W phase current IMW) flows. Then, in the brushless motor 6, the inner rotor (not shown) is driven in the forward rotation direction or the reverse rotation direction, and the motor shaft (not shown) rotates in the forward rotation or the reverse rotation. At this time, the electric motor current detection means 12 detects the electric motor current IM and transmits the electric motor current signal IMO to the drive device 5. Further, the electric motor rotation detection means 13 detects the electric motor rotation angle PM of the inner rotor (not shown) and transmits the electric motor rotation signal PMO to the drive device 5.

The rotational driving force of the motor shaft (not shown) of the brushless motor 6 is transmitted to the pinion shaft 7a via the torque limiter 10 and the gear type speed reducing mechanism 11. Then, on the pinion shaft 7a, this rotational driving force acts as an auxiliary torque to assist the steering torque (steering force) by the driver. As a result, the steering force by the driver is reduced.

A case where a data shift occurs due to the influence of noise on the data transmission communication line TW while the drive control microcomputer 50 is receiving data will be described.

As described above, the drive control microcomputer 50
Then, it is detected whether or not the data is normally received from the control microcomputer 40. Therefore, when the data shift occurs, the drive control microcomputer 50 detects that the data received from the control microcomputer 40 is abnormal, and the control microcomputer 40 outputs the LO signal as the standby signal to the standby signal communication line SW. To send over. By the way, after the data shift occurs, the drive control microcomputer 50 cannot receive the target current signal IMS and the like as normal data, so that the drive control of the brushless motor 6 cannot be performed normally.

Then, since the control microcomputer 40 monitors the HI signal / LO signal of the standby signal, it detects that the standby signal has switched from the HI signal to the LO signal. Then, the control microcomputer 40 temporarily stops the transmission of data to the drive control microcomputer 50.

When the data transmission to the drive control microcomputer 50 is stopped, the drive control microcomputer 50 confirms that the data is not transmitted, and the control microcomputer 40
Then, the HI signal is transmitted as a standby signal via the standby signal communication line SW.

Then, since the control microcomputer 40 monitors the HI signal / LO signal of the standby signal, it detects that the standby signal has switched from the LO signal to the HI signal. Then, the control microcomputer 40 starts transmitting data to the drive control microcomputer 50 again.

After the data transmission is restarted, the drive control microcomputer 50 eliminates the data shift and normally receives the data from the control microcomputer 40. Therefore, the drive control microcomputer 50 can normally control the drive of the brushless motor 6 based on the normal target current signal IMS, etc., and sets the normal electric motor control signal VO.

Then, in the electric motor drive circuit 51, the electric motor control signal VO set by the drive control microcomputer 50 causes the electric motor voltage VM to the brushless motor 6 in the same manner as described above.
Is applied. Then, the brushless motor 6 is driven in the forward rotation direction or the reverse rotation direction, and this rotational driving force acts as an auxiliary torque to assist the steering torque (steering force) by the driver. As a result, the steering force by the driver is reduced.

According to the electric power steering apparatus 1, since the EEPROM 43 can be shared by the control microcomputer 40 and the drive control microcomputer 50, the cost can be reduced. Further, according to the electric power steering apparatus 1, since the standby state is used to confirm the data reception state in the drive control microcomputer 50, the drive control microcomputer 50 operates normally when the ignition switch IG is turned on. Data can be reliably received, and normal data reception can be resumed even if a reception error occurs.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be implemented in various forms. For example, in the present embodiment, an EEPROM is connected to the control microcomputer and
Although the data stored in M is transmitted to the drive control microcomputer, the drive control microcomputer has an EEPROM.
May be connected, and the data stored in the EEPROM may be transmitted to the control microcomputer. Further, although the storage device is the EEPROM in the present embodiment, the EPRO
Other storage devices such as M and a mask ROM may be used. In the present embodiment, the HI signal is used when the data can be normally received as the standby signal, and L is received when the data cannot be received.
Although the O signal is used, other signal configurations such as setting the HI signal and the LO signal in reverse may be used, or only when the data can be normally received as the standby signal or when the reset of the data transmission is requested. You may make it transmit a specific signal.

[0091]

In the electric power steering apparatus according to the first aspect of the present invention, since one storage device is shared by the target current setting means and the drive control means, the cost can be reduced.

In the electric power steering apparatus according to the second aspect of the present invention, the drive control means transmits the standby signal, and the target current setting means receives the standby signal, and then starts transmitting data to the drive control means. As a result, the drive control means can reliably receive normal data.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an electric power steering device according to an embodiment.

FIG. 2 is a block configuration diagram of a control device and a drive device according to the present embodiment.

[Explanation of symbols]

1. Electric power steering device 4 ... Control device 5 ... Drive device 6 ... Brushless motor (electric motor) 12 ... Motor current detection means 13 ... Motor rotation detection means (motor phase detection means) 40 ... Control microcomputer (target current setting means) 43 ... EEPROM (memory device) 50: Drive control microcomputer (drive control means) 51 ... motor drive circuit (motor drive means) S: Steering system CW: clock communication line (communication line) RW: Communication line for data reception (communication line) SW: Standby signal communication line (communication line) TS: Steering torque sensor (steering torque detecting means) TW: Communication line for data transmission (communication line)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B62D 137: 00 H02P 6/02 371D F term (reference) 3D032 CC35 DA15 DA23 DA63 DA64 DD10 3D033 CA03 CA13 CA16 CA20 5H560 AA08 BB04 BB07 BB12 DA01 DA07 DB20 DC12 EB01 EB05 EC10 JJ02 SS02 TT13 TT15 UA05 XA02 XA04 XA11 XA12

Claims (2)

[Claims] 1. A motor for applying an auxiliary steering force to a steering system, and steering torque detecting means for detecting a steering torque acting on the steering system and outputting a steering torque signal.
Based on at least the steering torque signal, an electric motor phase detection unit that detects a rotation phase of the electric motor and outputs an electric motor phase signal, an electric motor current detection unit that detects an electric motor current flowing in the electric motor, and outputs an electric motor current signal. Target current setting means for setting a target current signal according to the above, drive control means for setting a motor control signal based on a deviation between the target current signal and the electric motor current signal and the electric motor phase signal, and based on the electric motor control signal An electric power steering device including a brushless motor, wherein the target current setting means and the drive control means are electrically connected by a communication line. A storage device is connected to either the target current setting means or the drive control means, When a storage device is connected to the target current setting means, the data stored in the storage device is transmitted from the target current setting means to the drive control means via the communication line, and the storage device is An electric power steering apparatus, wherein when connected to the drive control means, the data stored in the storage device is transmitted from the drive control means to the target current setting means via the communication line. . 2. A motor for applying an auxiliary steering force to a steering system, and steering torque detecting means for detecting a steering torque acting on the steering system and outputting a steering torque signal.
Based on at least the steering torque signal, an electric motor phase detection unit that detects a rotation phase of the electric motor and outputs an electric motor phase signal, an electric motor current detection unit that detects an electric motor current flowing in the electric motor, and outputs an electric motor current signal. Target current setting means for setting a target current signal according to the above, drive control means for setting a motor control signal based on the deviation between the target current signal and the motor current signal and the motor phase signal, and based on the motor control signal An electric power steering device including a brushless motor, wherein the target current setting means and the drive control means are electrically connected by a communication line. Then, the drive control means sends a standby signal indicating a state where data can be received to the target current setting hand. An electric power steering device, wherein the target current setting means starts transmitting data to the drive control means after receiving the standby signal.