JP2003312504A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device that controls a brushless motor in a way equivalent to a control means in a normal case even when abnormality in the two control means to separately control the brushless motor occurs. <P>SOLUTION: This electric power steering device is provided with a target electric current setting means (microcomputer for control) 40A to set a target electric current signal IMS, a drive control means (microcomputer for drive control) 50A to set an electric motor control signal VO and an electric motor drive means (electric motor driving circuit) 51 to drive the brushless motor 6 and constitutes its characteristic feature that the drive control means 50A takes in a steering torque signal T and sets the target electric current signal IMS in accordance with the steering torque signal T when the target electric current setting means 40A fails and/or the target electric current setting means 40A takes in an electric motor phase signal IMO and outputs the electric motor control signal VO to the electric motor drive means 51 by setting it when the drive control means 50A fails. <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, when one of the two microcomputers fails, a series of controls as the electric power steering device cannot be continued. Therefore, in the electric power steering device,
It becomes impossible to control the drive of the brushless motor, and it becomes impossible to give an auxiliary steering force to the steering system. In addition, control device (microcomputer) and drive control device (microcomputer)
If the control device (microcomputer) cannot receive the motor phase signal due to a disconnection of the communication line with the control device (microcomputer), the control device (microcomputer) cannot perform the damper control, and the steering feeling is deteriorated.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an electric power steering apparatus capable of performing control equivalent to normal control even when an abnormality occurs in two control means for controlling a brushless motor by division of labor. It is in.

[0007]

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 electric motor is an electric power steering device composed of a brushless motor, wherein the drive control means fetches a steering torque signal from the steering torque detecting means, and based on the steering torque signal when the target current setting means fails. The target current signal is set by setting the target current signal.

According to this electric power steering apparatus, even if the target current setting means composed of a microcomputer or the like fails and cannot be controlled, the drive control means composed of a microcomputer or the like is operated based on the steering torque signal. Set the target current signal. Then, in the electric power steering device, the control of the brushless motor can be continued only by the drive control means, and the auxiliary steering force can be applied to the steering system.

An electric power steering apparatus according to a second aspect 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, and outputs 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 an electric motor control signal based on a deviation from a signal and the electric motor phase signal; and an electric motor drive means for driving the electric motor based on the electric motor control signal, wherein the electric motor is a brushless motor. In the electric power steering apparatus, the target current setting means fetches a motor phase signal from the motor phase detection means, sets a motor control signal when the drive control means fails, and outputs the signal to the motor drive means. It is characterized by doing.

According to this electric power steering apparatus, even if the drive control means composed of the microcomputer or the like fails and cannot be controlled, the target current signal and the motor phase are set in the target current setting means composed of the microcomputer or the like. A motor control signal is set based on the signal and output to the motor drive circuit. Then, in the electric power steering device, the control of the brushless motor can be continued only by the target current setting means, and the auxiliary steering force can be applied to the steering system.

An electric power steering system according to a third aspect 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, and outputs 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 an electric motor control signal based on a deviation from a signal and the electric motor phase signal; and an electric motor drive means for driving the electric motor based on the electric motor control signal, wherein the electric motor is a brushless motor. In the electric power steering apparatus, the target current setting means takes in the electric motor phase signal from the electric motor phase detection means and performs damper control based on the electric motor phase signal, and the drive control means is the target When the current setting means cannot normally receive the motor phase signal, the motor phase signal is received. And performing damper control based on.

According to this electric power steering apparatus, even when the target current setting means cannot normally receive the motor phase signal, the drive control means composed of a microcomputer or the like performs damper control based on the motor phase signal. . In the electric power steering device, the drive control means performs the correction by the damper control on the target current signal (without the correction by the damper control) transmitted from the target current setting means, so that a good steering feeling can be maintained. .

Further, an electric power steering system according to a fourth aspect 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, and outputs 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 an electric motor control signal based on a deviation from a signal and the electric motor phase signal; and an electric motor drive means for driving the electric motor based on the electric motor control signal, wherein the electric motor is a brushless motor. The electric power steering apparatus is characterized in that the drive control means performs damper control based on the electric motor phase signal.

According to this electric power steering apparatus, the drive control means constituted by a microcomputer or the like always controls the damper based on the electric motor phase signal. Therefore, in this electric power steering device, even if reception failure occurs in the target current setting means, the drive control means corrects the target current signal by damper control, so that a good steering feeling can be maintained. it can.

[0015]

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 the electric power steering apparatus according to the present invention, even if one of the two control means (microcomputers or the like) for controlling the drive of the brushless motor fails, each control means has the other one in order to continue the series of control. At least the basic function of the control means is provided and a signal required for the basic control is taken in. Further, the electric power steering apparatus according to the present invention has a configuration in which the drive control unit has a damper control function in order to perform the damper control even when the electric motor phase signal necessary for the damper control cannot be taken into the target current setting unit. To do.

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 is arranged along the pinion shaft. 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, there are three embodiments in which the function of the control microcomputer and the function of the drive control microcomputer are different, and in the first embodiment, each microcomputer has the function of the other microcomputer. In the second embodiment, both microcomputers have a damper control function, and in the third embodiment only the drive control microcomputer has a damper control function.

First, the overall structure 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. In addition,
In the present embodiment, as described above, there are three embodiments, but the overall configuration of the electric power steering device 1 is common.

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 steering shaft 2a provided integrally with a steering wheel 3 and a connecting shaft 2b.
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 apparatus 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 device 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 from 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. In addition,
In the present embodiment, the steering torque sensor TS corresponds to the steering torque detecting means 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 device 5 generates the motor control signal VO based on the target current signal IMS and the detection signals IMO and PMO by the drive control microcomputers 50A, 50B and 50C, and the motor drive circuit 51 generates the motor control signal VO. Based on the motor voltage V to the brushless motor 6
M is applied (see FIGS. 2 to 4). In addition, the drive device 5
Is directly connected to the battery BT via the fuse FS and is also connected via the fuses FS and FS and the ignition switch IG, and is connected to the battery power source (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 detection means 13 corresponds to the electric motor phase detection means described in the claims, and the electric motor drive circuit 5
1 corresponds to the electric motor driving means described in the claims.

The vehicle speed sensor VS is a sensor for detecting 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 first embodiment will be described with reference to FIGS. 1 and 2. FIG. 2 is a block configuration diagram of the control device and the drive device according to the first embodiment. By the way, in the electric power steering device 1, since the brushless motor 6 is divided into two microcomputers for control, the brushless motor 6 cannot be controlled even if one of the two microcomputers fails. Therefore, in the first embodiment, each microcomputer 40A, 50
The function of the other microcomputer is incorporated in A, and the brushless motor 6 can be controlled by only one of the microcomputer 40A or the microcomputer 50A.

The configuration of the control device 4A according to the first embodiment will be described with reference to FIG.

The control device 4A is electrically connected to the drive device 5A by a wire harness WH, and communicates various signals via the wire harness WH (see FIG. 1). The control device 4A is a one-chip control microcomputer 40.
A, for storing the torque sensor I / F circuit 41 and vehicle speed sensor I / F circuit 42 included in the control microcomputer 40A, an output circuit (not shown) for various signals, and various data used by the control microcomputer 40A. EEPROM [Electri
The storage device (not shown) such as cally Erasable Programmable Read Only Memory] and a watchdog timer (not shown) are included. In addition, in the first embodiment, the control microcomputer 40A is defined by claim 1 and claim 2.
It corresponds to the target current setting means described in.

Then, the control device 4A takes in various detection signals T, V from the vehicle and the motor rotation speed signal SMO from the drive device 5A, and takes in the fetched signals T, V, SMO.
The target current to be applied to the brushless motor 6 is set based on the above. Further, the control device 4A takes in the electric motor rotation signal PMO (digital signal) and the electric motor current signal IMO (digital signal) from the drive device 5A, and when the drive control microcomputer 50A of the drive device 5A fails, the target current and Captured signal PMO (digital signal),
A motor control signal VO for controlling the drive of the brushless motor 6 is set based on IMO (digital signal), and is output to the motor drive circuit 51 of the drive device 5A.

Further, the control device 4A monitors the operation of the control microcomputer 40A by the watchdog timer, performs self-monitoring of the operation, and abnormally operates (fails) the operation of the control microcomputer 40A by the watchdog timer. If it is detected, a failure signal is transmitted to the drive unit 5A (drive control microcomputer 50A). Further, the control device 4A controls the watchdog pulse to drive and control the microcomputer 5.
0A, and the pulse is transmitted to the drive control microcomputer 50A.
The operation of the drive control microcomputer 50A is mutually monitored by confirming that a response is sent from.

Before describing the control configuration of the control microcomputer 40A, the torque sensor I / F circuit 41 and the vehicle speed sensor I / F circuit 42 will be described. Torque sensor I
The / F circuit 41 receives the steering torque signal T (analog signal) from the steering torque sensor TS and outputs the steering torque signal T (digital signal) to the target current setting unit 40a and the inertia control unit 40d. Torque sensor I / F
The 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. The vehicle speed sensor I / F circuit 42 converts the vehicle speed signal V, which is a pulse signal, into a digital signal. The steering torque signal T (digital signal) and the vehicle speed signal V (digital signal) are transmitted to the drive control microcomputer 50A in the first embodiment, but are different from those in the second and third embodiments. In the form, drive control microcomputers 50B, 50
Not sent to C (see FIGS. 3 and 4).

The control configuration of the control microcomputer 40A will be described. The control microcomputer 40A uses the target current signal IM
To set S, a target current setting unit 40a, a damper control unit 40b, a damper correction unit 40c, an inertia control unit 40
d and an inertia correction unit 40e, and a failure determination unit 40f for determining a failure of the drive control microcomputer 50A.
And a current converter 40g for realizing the function of the drive control microcomputer 50A (for setting the motor control signal VO) when the drive control microcomputer 50A fails.
Rotation angle converter 40h, torque deviation calculator 40i, magnetic field deviation calculator 40j, torque PI [Proportional Inte]
gral] control unit 40k, magnetic field PI control unit 40l, voltage conversion unit 40m, and PWM conversion unit 40n.

Further, the control microcomputer 40A generates a clock, executes processing based on the generated clock, and performs clock synchronous communication with the drive control microcomputer 50A based on this clock. Is going. Therefore, the control microcomputer 40A transmits the generated clock to the drive control microcomputer 50A.

In the control microcomputer 40A, when the drive control microcomputer 50A is normal, the target current signal IM
Failure determination unit 4 for determining failure of each unit 40a to 40e for setting S and the drive control microcomputer 50A
The processing at 0f is repeatedly executed every basic processing time (for control). Further, in the control microcomputer 40A, when the drive control microcomputer 50A is in failure, the processing in each of the units 40a to 40e and the failure determination unit 40f is repeatedly executed at every basic processing time (for control) and the processing is performed. Motor control signal VO
The processing in each of the units 40g to 40n for setting is repeatedly executed for each failure time processing time (for control). The processing time at the time of failure (for control) is longer than the basic processing time (for control), and the number of times of processing of each unit 40g to 40n per unit time is smaller than the number of times of processing executed by the drive control microcomputer 50A. In addition, when the drive control microcomputer 50A fails, the basic processing time (for control) may be set longer than the normal time to further secure the processing time of each unit 40g to 40n.

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 controller 40b will be described. The damper control unit 40b receives the motor rotation speed signal SMO transmitted from the drive control microcomputer 50A or the motor rotation speed signal SMO from the rotation angle conversion unit 40h, and outputs a damper control signal to the damper correction unit 40c. In the damper control unit 40b, the motor rotation speed signal SM is set based on the corresponding data of the motor rotation speed signal SMO and the damper control signal which are set in advance based on the experimental value or the design value.
The corresponding damper control signal is read using O as an address. The damper control signal is associated with a larger value as the electric motor rotation speed signal SMO is larger, with respect to the electric motor rotation speed signal SMO, in order to reduce the excessive effect of the assist and improve the steering feeling. In the damper control unit 40b, the vehicle speed signal V (digital signal) from the vehicle speed sensor I / F circuit 42 may be input, and the vehicle speed signal V may be taken into consideration to set the damper control signal.

The damper correction section 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 of the steering torque by the driver 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 damper correction) from the damper correction unit 40c and the inertia control signal from the inertia control unit 40d, and the failure determination unit 40f receives the target current signal IMS (after the damper correction and inertia). After correction) is output. By the way, in the inertia control by the inertia control unit 40d and the inertia correction unit 40e, deterioration of responsiveness due to inertia of the rotating portion of the brushless motor 6 is improved, and steering feeling is improved. That is, the brushless motor 6 does not immediately switch the rotation direction due to its inertia even when the direction in which the motor voltage VM is applied is changed when switching the rotation direction from the forward rotation to the reverse rotation or from the reverse rotation to the forward rotation. Therefore, in the inertia control, the switching of the rotation direction of the brushless motor 6 is controlled to coincide with the switching timing of the rotation direction of the steering wheel 3. Therefore, the inertia control is performed by the target current signal IM
S is increased 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 calculate the target current signal IMS (after the damper correction and after the inertia correction).

The failure determination unit 40f will be described. The failure determination unit 40f receives the target current signal IMS (after damper correction and after inertia correction) from the inertia correction unit 40e, and sends the target current signal IMS (after damper correction and after inertia correction) to the drive control microcomputer 50A. It is transmitted or output to the torque deviation calculation unit 40i. In the failure determination unit 40f, when it is determined that the drive control microcomputer 50A is normal, the target current signal IMS is transmitted to the drive control microcomputer 50A, and when it is determined that the drive control microcomputer 50A is in failure. The processing in each unit 40g to 40n for setting the motor control signal VO is executed and the target current signal IMS is output to the torque deviation calculation unit 40i. Therefore, the failure determination unit 40f determines whether the drive control microcomputer 50A is normal or failed based on a failure signal from the drive device 5A and a reply to the watchdog pulse transmitted to the drive control microcomputer 50A. ing. By the way, in the failure determination unit 40f, in the case where the drive control microcomputer 50A is set as a failure by the failure signal, or when there is no reply to the watchdog pulse or the content of the reply is incorrect, Then, the drive control microcomputer 50A is determined to be in failure.

The current converter 40g will be described. The current conversion unit 40g includes a motor current signal IMO (digital signal) transmitted from the drive unit 5A and the rotation angle conversion unit 4.
The motor rotation phase signal from 0h is input, and the torque deviation calculation unit 40i outputs a torque control current signal and the magnetic field deviation calculation unit 40j outputs a magnetic field control current signal. The current converter 40g performs the same process as the current converter 50b of the drive control microcomputer 50A.

The rotation angle converter 40h will be described. The rotation angle conversion unit 40h receives the motor rotation signal PMO (digital signal) transmitted from the drive device 5A, outputs a motor rotation phase signal to the current conversion unit 40g and the voltage conversion unit 40m, and outputs the motor to the damper control unit 40b. The rotation speed signal SMO is output. In the rotation angle conversion unit 40h, the rotation angle conversion unit 50c of the drive control microcomputer 50A.
Perform the same processing as.

The torque deviation calculator 40i will be described. The torque deviation calculation unit 40i receives the target current signal IMS (after damper correction and inertia correction) from the failure determination unit 40f and the torque control current signal from the current conversion unit 40g, and the torque deviation PI control unit 40k. Outputs the torque control deviation signal. Torque deviation calculator 40i
Then, the same processing as that of the torque deviation calculator 50d of the drive control microcomputer 50A is performed.

The magnetic field deviation calculator 40j will be described. The magnetic field deviation calculation unit 40j receives the magnetic field control current signal from the current conversion unit 40g, and receives the magnetic field PI control unit 4j.
The magnetic field control deviation signal is output to 0l. The magnetic field deviation calculator 40j performs the same processing as the magnetic field deviation calculator 50e of the drive control microcomputer 50A.

The torque PI controller 40k will be described. The torque PI control unit 40k receives the torque control deviation signal from the torque deviation calculation unit 40i and outputs the torque PI control signal (DC voltage component) to the voltage conversion unit 40m. The torque PI control unit 40k performs the same processing as the torque PI control unit 50f of the drive control microcomputer 50A.

The magnetic field PI controller 40l will be described. The magnetic field PI control unit 40l includes a magnetic field deviation calculation unit 40.
The deviation signal for magnetic field control from j is input to the voltage conversion unit 4
The PI control signal for magnetic field (DC voltage component) is output at 0 m. The magnetic field PI control unit 40l performs the same processing as the magnetic field PI control unit 50g of the drive control microcomputer 50A.

The voltage converter 40m will be described. The voltage conversion unit 40m receives the motor rotation phase signal from the rotation angle conversion unit 40h and the torque P signal from the torque PI control unit 40k.
I control signal (DC voltage component) and magnetic field PI control unit 4
The magnetic field PI control signal (DC voltage component) from 0l is input, and the PI control signal (three-phase AC voltage component) is output to the PWM conversion unit 40n. The voltage conversion unit 40m performs the same processing as the voltage conversion unit 50h of the drive control microcomputer 50A.

The PWM converter 40n will be described. P
The WM conversion unit 40n receives the PI control signal (three-phase AC voltage component) from the voltage conversion unit 40m and transmits the electric motor control signal VO to the electric motor drive circuit 51 of the drive device 5A.
The PWM conversion unit 40n performs the same processing as the PWM conversion unit 50i of the drive control microcomputer 50A.

With reference to FIG. 2, the structure of the driving device 5A according to the first embodiment will be described.

The drive unit 5A is electrically connected to the control unit 4A by the wire harness WH and communicates various signals via the wire harness WH (see FIG. 1). The drive unit 5A includes a one-chip drive control microcomputer 50A, a motor drive circuit 51, and a motor current I / F circuit 5
2, an R / D conversion circuit 53, an output circuit (not shown) for various signals, a storage device (not shown) such as an EEPROM for storing various data used by the drive control microcomputer 50A, and a watchdog timer ( (Not shown) and the like. In the first embodiment, the drive control microcomputer 50A corresponds to the drive control means described in claims 1 and 2.

Then, the drive unit 5A fetches various detection signals IMO, PMO from the vehicle and the target current signal IMS (after damper correction and inertia correction) from the control unit 4A, and based on the fetched 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 5A takes in the steering torque signal T (digital signal) and the vehicle speed signal V (digital signal) from the control unit 4A, and the signal T (when the control microcomputer 40A of the control unit 4A fails). Based on the digital signal), V (digital signal), and the motor rotation speed signal SMO, a target current to be passed through the brushless motor 6 is set.

In addition, the drive unit 5A monitors the operation of the drive control microcomputer 50A by the watchdog timer, and self-monitors the operation, and the operation of the drive control microcomputer 50A is abnormal (faulty) by the watchdog timer. ) Is detected, a failure signal is transmitted to the control device 4A (control microcomputer 40A). Further, the drive unit 5A uses the watchdog pulse control microcomputer 40A.
To the control microcomputer 4A by confirming that the pulse is returned from the control microcomputer 40A.
Mutual monitoring of 0A operation.

Before describing the drive control microcomputer 50A, the motor current I / F circuit 52 and the R / D conversion circuit 5 are described.
3 will be described. Motor current I / F circuit 52
Is a motor current signal IM from the motor current detection means 12.
O (analog signal) is input to drive control microcomputer 5
The motor current signal IMO (digital signal) is output to 0A. The motor current I / F circuit 52 converts the analog motor signal IMO into a digital signal. Further, the R / D conversion circuit 53 receives the electric motor rotation signal PMO (analog signal) from the electric motor rotation detection means 13 and inputs the electric motor rotation signal P to the drive control microcomputer 50A.
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 electric motor current signal IMO (digital signal) and the electric motor rotation signal PMO
The (digital signal) is transmitted to the control microcomputer 40A in the first embodiment, but is not transmitted to the control microcomputers 40B and 40C in the second and third embodiments (see FIG. 3 and (See FIG. 4).

The drive control microcomputer 50A will be described. The drive control microcomputer 50A is the control microcomputer 40.
A failure determination unit 50a is provided to determine the failure of A, and a current conversion unit 50b is provided to set the motor control signal VO.
The control microcomputer 40A includes a rotation angle conversion unit 50c, a torque deviation calculation unit 50d, a magnetic field deviation calculation unit 50e, a torque PI control unit 50f, a magnetic field PI control unit 50g, a voltage conversion unit 50h, and a PWM conversion unit 50i. If a failure occurs, the target current setting unit 50j, the damper control unit 50k, and the damper correction unit for realizing the function of the control microcomputer 40A (for setting the target current signal IMS (after the damper correction and after the inertia correction)) 50l, inertia control unit 50m
And an inertia correction unit 50n.

Further, the drive control microcomputer 50A generates a clock, and the processing is executed based on this clock. The drive control microcomputer 50A performs clock-synchronous communication with the control microcomputer 40A based on the clock transmitted from the control microcomputer 40A.

In the drive control microcomputer 50A,
When the control microcomputer 40A is normal, the motor control signal V
Failure determination unit 50a for determining failure of each unit 50b to 50i for setting O and control microcomputer 40A
The processing in (1) is repeatedly executed every basic processing time (for drive control). Further, in the drive control microcomputer 50A, when the control microcomputer 40A is out of order, the processes in the respective units 50b to 50i and the failure determination unit 50a are repeatedly executed at every basic process time (for control), and the process is performed. Target current signal IM by using free time
The processing in each of the units 50j to 50n for setting S (after damper correction and after inertia correction) is repeatedly executed for each failure time processing time (for drive control). The processing time at the time of failure (for drive control) is longer than the basic processing time (for drive control), and the number of processes per unit time of each unit 50j to 50n is less than the number of processes executed by the control microcomputer 40A. When the control microcomputer 40A fails, the basic processing time (for drive control) may be set longer than the normal processing time to further secure the processing time of each unit 50j to 50n.

The failure determination unit 50a will be described. The failure determination unit 50a receives the target current signal IMS (after damper correction and after inertia correction) transmitted from the control microcomputer 40A or the target current signal IMS (after damper correction and after inertia correction) from the inertia correction unit 50n. , Any one of the target current signals IMS (after damper correction and after inertia correction) is output to the torque deviation calculation unit 50d. In the failure determination unit 50a, the control microcomputer 40
When it is determined that A is normal, the control microcomputer 40
The target current signal IMS transmitted from A is output, and when it is determined that the control microcomputer 40A is in failure, the processes in the respective units 50j to 50n for setting the target current signal IMS are executed and the inertia correction unit 50n is executed.
From the target current signal IMS. Therefore, the failure determination unit 50a uses the control microcomputer 40A based on the failure signal from the control device 4A and the reply to the watchdog pulse transmitted to the control microcomputer 40A.
It is determined whether is normal or broken. By the way, in the failure determination unit 50a, when the control microcomputer 40A is set to be in failure by the failure signal, or when there is no reply to the watchdog pulse or the content of the reply is incorrect, either It is determined that the control microcomputer 40A has failed.

The current converter 50b will be described. The current conversion unit 50b 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 conversion unit 50c, and the torque deviation calculation unit 50d receives the torque control current. A magnetic field control current signal is output to the signal and magnetic field deviation calculation unit 50e.
In the current converter 50b, 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, and the like, and the torque control current signal is obtained. 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 50c will be described. The rotation angle conversion unit 50c 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 50b and the voltage conversion unit 50h, and controls the control microcomputer 40A. The motor rotation speed signal SMO is transmitted to the damper control unit 50k and the motor rotation speed signal SMO is output to the damper control unit 50k. Rotation angle conversion unit 50
In c, the rotation speed of the brushless motor 6 is calculated based on the rotation angle and the rotation direction of the electric motor rotation signal PMO, and the electric motor rotation speed signal SMO is set. Also, the rotation angle conversion unit 5
At 0c, an accurate rotation phase in consideration of the lead angle is calculated based on the rotation angle, rotation direction and rotation speed of the motor rotation signal PMO, and the motor rotation phase signal is set.

The torque deviation calculator 50d will be described. The torque deviation calculation unit 50d receives the target current signal IMS (after damper correction and after inertia correction) from the failure determination unit 50a and the torque control current signal from the current conversion unit 50b, and inputs the torque PI control unit 50f. Outputs the torque control deviation signal. Torque deviation calculator 50d
Then, the torque control current signal is subtracted from the target current signal IMS to set the torque control deviation signal.

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

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

The voltage converter 50h will be described. The voltage conversion unit 50h uses the motor rotation phase signal from the rotation angle conversion unit 50c and the torque P control signal from the torque PI control unit 50f.
I control signal (DC voltage component) and magnetic field PI control unit 5
The magnetic field PI control signal (DC voltage component) from 0 g is input, and the PI control signal (three-phase AC voltage component) is output to the PWM conversion unit 50i. The voltage conversion unit 50h determines the winding of the phase to which the motor voltage is applied among the three-phase (U-phase, V-phase, W-phase) windings based on the motor rotation phase signal. Then, the voltage conversion unit 50h 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 50i will be described. P
The WM converter 50i receives the PI control signal (three-phase AC voltage component) from the voltage converter 50h and outputs the motor control signal VO to the motor drive circuit 51. PWM converter 5
At 0i, 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 50i, 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 50f and 50g 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 50h determines the winding of the phase to be energized based on the motor rotation phase signal. ing.

The target current setting section 50j will be described.
The target current setting unit 50j controls the steering torque signal T (digital signal) and the vehicle speed signal V transmitted from the control device 4A.
(Digital signal) is input and the target current signal IMS is output to the damper correction unit 501. Target current setting unit 50j
Then, the same processing as the target current setting unit 40a of the control microcomputer 40A is performed.

The damper controller 50k will be described. The damper control unit 50k receives the motor rotation speed signal SMO from the rotation angle conversion unit 50c and outputs a damper control signal to the damper correction unit 501. In the damper control unit 50k,
The same processing as the damper control unit 50b of the control microcomputer 40A is performed.

The damper correction unit 501 will be described. The damper correction unit 501 receives the target current signal IMS from the target current setting unit 50j and the damper control signal from the damper control unit 50k, and outputs the target current signal IMS (after the damper correction) to the inertia correction unit 50n. The damper correction unit 50l includes the damper correction unit 4 of the control microcomputer 40A.
The same process as 0c is performed.

The inertia controller 50m will be described. The inertia control unit 50m receives the steering torque signal T (digital signal) and the vehicle speed signal V (digital signal) transmitted from the control device 4A, and outputs the inertia control signal to the inertia correction unit 50n. The inertia control unit 50m performs the same processing as the inertia control unit 40d of the control microcomputer 40A.

The inertia correction unit 50n will be described. The inertia correction unit 50n receives the target current signal IMS (after the damper correction) from the damper correction unit 501 and the inertia control signal from the inertia control unit 50m, and the failure determination unit 50a receives the target current signal IMS (after the damper correction and the inertia). After correction) is output. The inertia correction unit 50n performs the same processing as the inertia correction unit 40e of the control microcomputer 40A.

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 50A (however, when the drive control microcomputer 50A is out of order, the electric motor control signal VO transmitted from the control microcomputer 40A is input). , The motor voltage VM is applied to the brushless motor 6. Therefore, the electric motor drive circuit 51 includes the FETs 51a, 51b, 5
A bridge circuit is configured by 1c, 51d, 51e, and 51f, and a power supply voltage 51g supplies a voltage of 12V. Further, the electric motor drive circuit 51 is connected to the U of the brushless motor 6.
_{The 0} terminal is connected to the connection end of the source Sa of the FET 51a and the drain Db of the FET 51b, and the brushless motor 6
V ₀ terminal is the source Sc of FET 51c and FET 51d
Is connected to the connecting end of the drain Dd, W ₀ terminal of the brushless motor 6 and the source of Se FET51e FET 5
It is connected to the connection end with the drain Df of 1f. FE
The PWM signal or the OFF signal is input to each of the gates Ga to Gf, and T51a to 51f are turned on when the PWM signal is input and the logic level is 1. The electric motor voltage VM applied to the brushless motor 6 is selectively PWM.
It is determined by the duty ratio of the PWM signal of the driven FET.

Now, with reference to FIGS. 1 and 2, the operation of the control device 4A and the drive device 5A in the electric power steering device 1 according to the first embodiment will be described. Here, a case where both the control microcomputer 40A and the drive control microcomputer 50A are normal, the drive control microcomputer 50A has a failure, and the control microcomputer 40A has a failure will be described.

A case where both the control microcomputer 40A and the drive control microcomputer 50A are normal will be described.

In the control microcomputer 40A, the target current signal IMS is set based on the steering torque signal T and the vehicle speed signal V for each basic processing time (for control), and the steering torque signal T is set in the target current signal IMS. , Vehicle speed signal V and electric motor rotation speed signal SM from drive control microcomputer 50A
Correction based on O is performed by damper control and inertia control.

The control microcomputer 40A determines that the drive control microcomputer 50A is normal based on the failure signal from the drive unit 5A and the reply to the watchdog pulse from the drive control microcomputer 50A. Then, the control microcomputer 40A transmits the target current signal IMS that has been subjected to the damper correction and the inertia correction to the drive device 5A (drive control microcomputer 50A). Incidentally, the control microcomputer 40A does not execute the processes in the respective units 40g to 40n.

On the other hand, the drive control microcomputer 50A determines that the control microcomputer 40A is normal based on the failure signal from the control device 4A and the reply to the watchdog pulse from the control microcomputer 40A. In this case, the drive control microcomputer 50A uses the target current signal IMS transmitted from the control microcomputer 40A for processing. By the way,
The drive control microcomputer 50A does not execute the processing in each unit 50j to 50n.

In the drive control microcomputer 50A,
Target current signal IM for each basic processing time (for drive control)
The motor control signal VO is set based on S, the motor current signal IMO (digital signal) and the motor rotation signal PMO (digital signal).

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 unit 5A. 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 5A.

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 the drive control microcomputer 50A is out of order will be described.

In the control microcomputer 40A, the target current signal IMS is set based on the steering torque signal T and the vehicle speed signal V for each basic processing time (for control), and further, the steering torque signal T is set in the target current signal IMS. , Vehicle speed signal V and electric motor rotation speed signal SM from drive control microcomputer 50A
Correction based on O is performed by damper control and inertia control.

Further, the control microcomputer 40A determines that the drive control microcomputer 50A is in failure based on the failure signal from the drive unit 5A and the reply to the watchdog pulse from the drive control microcomputer 50A, and the drive control microcomputer 50A. Execute the process to realize the function of. That is, in the control microcomputer 40A, the target current signal IMS and the electric motor current signal IMO (digital signal) and the electric motor rotation signal PMO (digital signal) transmitted from the drive device 5A are used for each failure processing time (for control). Then, the electric motor control signal VO is set and transmitted to the electric motor drive circuit 51 of the drive unit 5A.

On the other hand, since the drive control microcomputer 50A is out of order, the motor control signal VO cannot be set. Therefore, the motor control signal VO is not output from the drive control microcomputer 50A to the motor drive circuit 51.

However, in the electric motor drive circuit 51, the electric motor control signal VO transmitted from the control microcomputer 40A 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.

The case where the control microcomputer 40A is out of order will be described.

Since the control microcomputer 40A is out of order, the target current signal IMO cannot be set. Therefore, the target current signal IMO is not output from the control microcomputer 40A to the drive control microcomputer 50A.

However, in the drive control microcomputer 50A,
Based on the failure signal from the control device 4A and the reply to the watchdog pulse from the control microcomputer 40A, the control microcomputer 40A is determined to be in failure, and the control microcomputer 40A
The processing for realizing the function A is executed. In other words, the drive control microcomputer 50A sets the target current signal IMS based on the steering torque signal T and the vehicle speed signal V transmitted from the control device 4A for each failure time processing time (for drive control). The target current signal IMS is corrected by damper control and inertia control based on the steering torque signal T, the vehicle speed signal V, and the motor rotation speed signal SMO transmitted from the control device 4A.

Further, in the drive control microcomputer 50A,
For each basic processing time (for drive control), the electric motor control signal VO is set based on the target current signal IMS and the electric motor current signal IMO (digital signal) and the electric motor rotation signal PMO (digital signal) set by itself.

Then, in the electric motor drive circuit 51, the electric motor voltage VM is applied to the brushless motor 6 in the same manner as described above by the electric motor control signal VO set by the drive control microcomputer 50A.
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 first embodiment, even if the drive control microcomputer 50A fails, the control microcomputer 40A
A detects the failure and the drive control microcomputer 5
Since the function of 0A is performed instead, the auxiliary steering force can be continuously applied to the steering system S. Further, according to the first embodiment, even when the control microcomputer 40A fails, the drive control microcomputer 50A detects the failure and performs the function of the control microcomputer 40A instead. The auxiliary steering force can be continuously applied. That is, according to the first embodiment,
Even if one of the two microcomputers 40A and 50A fails, the assist by the assist steering force with respect to the steering torque (steering force) of the driver does not stop. Furthermore, according to the first embodiment, the substitute processing at the time of failure is performed by utilizing the idle time of the normal processing in each of the microcomputers 40A and 50A. You don't have to use good things.

The second embodiment will be described with reference to FIGS. 1 and 3. FIG. 3 is a block configuration diagram of a control device and a drive device according to the second embodiment. By the way, since the microcomputer of the control device 4 performs the correction by the damper control based on the signal transmitted from the microcomputer of the drive device 5, when the signal from the microcomputer of the drive device 5 cannot be received, the correction by the damper control is performed. Can't do. Without correction by damper control, sudden steering from the steering wheel 3 or steered wheels W,
Since the vibration from W, a reaction force that changes abruptly, and the like are reflected in the drive of the brushless motor 6 and applied to the auxiliary steering force, the steering feeling is reduced. Therefore, in the second embodiment, the control microcomputer 40B controls the electric motor rotation speed signal SMO.
Is not received normally, the drive control microcomputer 5
The target current signal IMS can be corrected by damper control at 0B. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The configuration of the control device 4B according to the second embodiment will be described with reference to FIG.

The control device 4B is electrically connected to the drive device 5B by a wire harness WH, and communicates various signals via the wire harness WH (see FIG. 1). The control device 4B is a one-chip control microcomputer 40.
B, for storing the torque sensor I / F circuit 41 and the vehicle speed sensor I / F circuit 42 included in the control microcomputer 40B, an output circuit (not shown) for various signals, and various data used by the control microcomputer 40B. It is composed of a storage device (not shown) such as an EEPROM and a watchdog timer (not shown). In the second embodiment, the control microcomputer 40B corresponds to the target current setting means described in claim 3.

Then, the control device 4B takes in the various detection signals T, V from the vehicle and the motor rotation speed signal SMO from the drive device 5B, and takes in the fetched signals T, V, SMO.
The target current to be applied to the brushless motor 6 is set based on the above.

The control configuration of the control microcomputer 40B will be described. The control microcomputer 40B uses the target current signal IM
To set S, a target current setting unit 40a, a damper control unit 40p, a damper correction unit 40c, an inertia control unit 40
d and an inertia correction unit 40e.

Further, the control microcomputer 40B generates a clock, executes processing based on the generated clock, and performs clock synchronous communication with the drive control microcomputer 50B based on this clock. Is going. Therefore, the control microcomputer 40B transmits the generated clock to the drive control microcomputer 50B.

Further, the control microcomputer 40B verifies whether or not the signal (in particular, the motor rotation speed signal SMO) from the drive control microcomputer 50B is normally received, with respect to the signal received from the drive control microcomputer 50B. The determination is made by chucking or a sum check, or by whether or not a signal can be received from the drive control microcomputer 50B within a preset time (a time longer than the specified reception interval by a predetermined time). Then, the control microcomputer 40B transmits to the drive control microcomputer 50B a reception state signal in which a signal from the drive control microcomputer 50B is set to indicate normal reception or poor reception. Incidentally, the cause of the poor reception is considered to be a disconnection of a communication line, an influence of noise on the communication line, a failure of a circuit for generating a signal such as a motor rotation speed signal SMO, and a failure of a detection means such as the motor rotation detection means 13. To be

Then, in the control microcomputer 40B, when the motor rotation speed signal SMO is normally received, the respective parts 40a, 40c for setting the target current signal IMS,
The processing in 40d, 40e, and 40p is repeatedly executed for each basic processing time (for control). At this time, the target current signal IMS transmitted from the control microcomputer 40B to the drive control microcomputer 50B has been corrected by damper control and inertia control. Further, in the control microcomputer 40B, when the electric motor rotation speed signal SMO is not normally received, the processing in each unit 40a, 40c, 40d, 40e, 40p is performed without performing the correction by the damper control and the basic processing time (control ) Repeat every time. At this time, the target current signal IMS transmitted from the control microcomputer 40B to the drive control microcomputer 50B is only corrected by inertia control.

The damper control section 40p will be described. The damper control unit 40p receives the electric motor rotation speed signal SMO transmitted from the drive control microcomputer 50B and outputs a damper control signal to the damper correction unit 40c. In the damper control unit 40p, when the electric motor rotation speed signal SMO is normally received, the electric motor rotation speed signal SMO is preset based on an experimental value or a design value, and based on the corresponding data of the damper control signal. The corresponding damper control signal is read by using the rotation speed signal SMO as an address. On the other hand, in the damper control unit 40p, the motor rotation speed signal SM
When O is not normally received, 0 is set in the damper control signal.

With reference to FIG. 3, the structure of the driving device 5B according to the second embodiment will be described.

The drive unit 5B is electrically connected to the control unit 4B by the wire harness WH, and communicates various signals via the wire harness WH (see FIG. 1). The drive unit 5B includes a one-chip drive control microcomputer 50B, a motor drive circuit 51, and a motor current I / F circuit 5
2, an R / D conversion circuit 53, an output circuit (not shown) for various signals, a storage device (not shown) such as an EEPROM for storing various data used by the drive control microcomputer 50B, and a watchdog timer ( (Not shown) and the like. In the second embodiment, the drive control microcomputer 50B corresponds to the drive control means described in claim 3.

Then, the drive unit 5B 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 4B, 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, in the drive unit 5B, when the control microcomputer 40B of the control unit 4B cannot normally receive the electric motor rotation speed signal SMO, the target current signal IMS (after inertia correction) is corrected by the damper control based on the electric motor rotation speed signal SMO. Give.

The drive control microcomputer 50B will be described. The drive control microcomputer 50B uses the motor control signal VO
Current conversion unit 50b and rotation angle conversion unit 50 for setting
c, torque deviation calculator 50d, magnetic field deviation calculator 50
e, torque PI controller 50f, magnetic field PI controller 50
g, a voltage conversion unit 50h, a PWM conversion unit 50i, and a correction determination unit 50p for determining whether the target current signal IMS is corrected by damper control. The target current signal IMS is corrected by damper control. A damper control unit 50q and a damper correction unit 50r are provided for performing the operation.

Further, the drive control microcomputer 50B generates a clock, and the processing is executed based on this clock. The drive control microcomputer 50B performs clock-synchronous communication with the control microcomputer 40B based on the clock transmitted from the control microcomputer 40B.

Then, in the drive control microcomputer 50B,
When the control microcomputer 40B normally receives the electric motor control signal VO, the processing in the respective units 50b to 50i for setting the electric motor control signal VO and the correction determination unit 50p for determining the presence / absence of correction by the damper control is performed. It is repeatedly executed every basic processing time (for drive control). In the drive control microcomputer 50B, the control microcomputer 4
When the motor rotation speed signal SMO is not normally received at 0B, the processing in each of the units 50b to 50i and the correction determination unit 50p is repeatedly executed for each basic processing time (for control) as in the above, and the processing is free. The processing in each of the units 50q and 50r for performing the correction by the damper control on the target current signal IMS (after the inertia correction) by using the time is repeatedly executed for each correction time processing time (for the drive control). The correction processing time (for drive control) is longer than the basic processing time (for drive control), and the number of processes per unit time of each unit 50q, 50r is less than the number of processes executed by the control microcomputer 40B. In addition, each part 50q, 50r
When the processing load due to is small, the respective units 50q and 50r may be repeatedly executed every basic processing time (for drive control).

The torque deviation calculator 50d will be described. The torque deviation calculation unit 50d has the same configuration as the torque deviation calculation unit 50d according to the first embodiment (see FIG. 2), but in the second embodiment, the target current signal IM.
S (after damper correction and after inertia correction) is input from the correction determination unit 50p.

The correction determination unit 50p will be described. The correction determination unit 50p receives the target current signal IMS (after the damper correction and after the inertia correction) transmitted from the control microcomputer 40B or the target current signal I from the damper correction unit 50r.
MS (after damper correction and after inertia correction) is input, and one of the target current signals IMS (after damper correction and after inertia correction) is output to the torque deviation calculation unit 50d. In the correction determination unit 50p, the control microcomputer 40
When it is determined that the motor rotation speed signal SMO is normally received at B (when it is determined that the target current signal IMS is corrected by the damper control), the target current transmitted from the control microcomputer 40B. Outputs the signal IMS,
When the control microcomputer 40B determines that the motor rotation speed signal SMO is not normally received (the target current signal IM
When it is determined that S has not been corrected by damper control), each unit 50q, 50r for correcting the target current signal IMS (after inertia correction) by damper control
And the damper correction unit 50r.
From the target current signal IMS. Therefore, the correction determination unit 50p determines whether or not the control microcomputer 40B is normally receiving the electric motor rotation speed signal SMO based on the reception state signal from the control microcomputer 40B.

The damper controller 50q will be described. The damper control unit 50q receives the motor rotation speed signal SMO from the rotation angle conversion unit 50c and outputs a damper control signal to the damper correction unit 50r. Since the damper control unit 50p performs the same processing as the damper control unit 40b according to the first embodiment (see FIG. 2), the description thereof will be omitted.

The damper correction unit 50r will be described. The damper correction unit 50r receives the target current signal IMS (after inertia correction) transmitted from the control microcomputer 40B and the damper control signal from the damper control unit 50q, and the correction determination unit 50p receives the target current signal IMS (after damper correction). And (after inertia correction) is output. Damper correction unit 50r
Then, the damper control signal is subtracted from the target current signal IMS (after inertia correction) to calculate the target current signal IMS (after damper correction and after inertia correction).

The operations of the control device 4B and the drive device 5B according to the second embodiment of the electric power steering device 1 will be described with reference to FIGS. 1 and 3. Here, the case where the control microcomputer 40B normally receives the electric motor rotation speed signal SMO and the control microcomputer 40B does not normally receive the electric motor rotation speed signal SMO will be described.

A case where the control microcomputer 40B normally receives the electric motor rotation speed signal SMO will be described.

In the control microcomputer 40B, the target current signal IMS is set based on the steering torque signal T and the vehicle speed signal V for each basic processing time (for control), and further, the steering torque signal T is set in the target current signal IMS. , The vehicle speed signal V and the motor rotation speed signal SM from the drive control microcomputer 50B
Correction based on O is performed by damper control and inertia control.

On the other hand, the drive control microcomputer 50B determines that the control microcomputer 40B normally receives the electric motor rotation speed signal SMO based on the reception state signal from the control microcomputer 40B. In this case, the drive control microcomputer 50B inputs the target current signal IMS (after the damper correction and after the inertia correction) transmitted from the control microcomputer 40B to the torque deviation calculation unit 50d. Incidentally, in the drive control microcomputer 50B, each part 50q, 5
The process at 0r is not executed.

Then, in the drive control microcomputer 50B,
Control microcomputer 40 for each basic processing time (for drive control)
The motor control signal VO is set based on the target current signal IMS (after damper correction and after inertia correction) from B, the motor current signal IMO (digital signal) and the motor rotation signal PMO (digital signal).

Then, similarly to the first embodiment, the electric motor drive circuit 51 applies the electric motor voltage VM to the brushless motor 6 by the electric motor control signal VO. Then,
The brushless motor 6 is driven in the forward rotation direction or the reverse rotation direction, and this rotational drive 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 the control microcomputer 40B does not normally receive the motor rotation speed signal SMO will be described.

In the control microcomputer 40B, the target current signal IMS is set based on the steering torque signal T and the vehicle speed signal V for each basic processing time (for control), and the steering torque signal T is set in the target current signal IMS. , Correction by inertia control is performed based on the vehicle speed signal V. At this time, since the control microcomputer 40B does not normally receive the electric motor rotation speed signal SMO from the drive control microcomputer 50B, the target current signal IMS cannot be corrected by the damper control.

However, in the drive control microcomputer 50B,
Based on the reception state signal from the control microcomputer 40B, the control microcomputer 40B determines that the motor rotation speed signal SMO is not normally received, and the target current signal IMS is corrected by the damper control. The process in is executed. That is, the drive control microcomputer 50
In B, a damper control signal is generated based on the motor rotation speed signal SMO for each correction time processing time (for drive control),
With this damper control signal, the target current signal IMS (after inertia correction) transmitted from the control microcomputer 40B is corrected by damper control.

Then, in the drive control microcomputer 50B,
The damper correction unit 50r is provided for each basic processing time (for drive control).
Target current signal IMS (after damper correction and inertia correction), motor current signal IMO (digital signal)
And the motor control signal VO is set based on the motor rotation signal PMO (digital signal).

Then, similarly to the first embodiment, the electric motor drive circuit 51 applies the electric motor voltage VM to the brushless motor 6 by the electric motor control signal VO. Then,
The brushless motor 6 is driven in the forward rotation direction or the reverse rotation direction, and this rotational drive 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 second embodiment, even when the control microcomputer 40B cannot normally receive the electric motor rotation speed signal SMO, the drive control microcomputer 50B corrects the damper control based on the electric motor rotation speed signal SMO. Since it can be performed, the steering feeling does not deteriorate. That is, according to the second embodiment, even if the control microcomputer 40B cannot perform the damper control correction, the drive control microcomputer 50B continues the damper control correction to maintain a good steering feeling. can do. Further, according to the second embodiment, the damper control process is performed by utilizing the idle time of the normal process in the drive control microcomputer 50B, which is superior to the conventional microcomputer in the processing capability of the drive control microcomputer 50B. Need not be used.

A third embodiment will be described with reference to FIGS. 1 and 4. FIG. 4 is a block configuration diagram of a control device and a drive device according to the third embodiment. By the way, if the microcomputer of the control device 4 performs the correction by the damper control based on the signal transmitted from the microcomputer of the drive device 5, if the signal from the microcomputer of the drive device 5 cannot be received, the correction by the damper control should be performed. I can't. Therefore, in the third embodiment, the control microcomputer 4
The drive control microcomputer 5 that generates the motor rotation speed signal SMO instead of performing correction by damper control at 0C.
It is configured to perform correction by damper control at 0C. In addition,
In the third embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

The configuration of the control device 4C according to the third embodiment will be described with reference to FIG.

The control device 4C is electrically connected to the drive device 5C by the wire harness WH, and communicates various signals via the wire harness WH (see FIG. 1). The control device 4C is a one-chip control microcomputer 40.
C, for storing the torque sensor I / F circuit 41 and the vehicle speed sensor I / F circuit 42 included in the control microcomputer 40C, an output circuit (not shown) for various signals, and various data used by the control microcomputer 40C. It is composed of a storage device (not shown) such as an EEPROM and a watchdog timer (not shown). In the third embodiment, the control microcomputer 40C corresponds to the target current setting unit described in claim 4.

Then, the control device 4C takes in various detection signals T and V from the vehicle and sets a target current to be passed through the brushless motor 6 based on the taken-in signals T and V.

The control configuration of the control microcomputer 40C will be described. The control microcomputer 40C uses the target current signal IM
A target current setting unit 40a, an inertia control unit 40d, and an inertia correction unit 40s for setting S are provided.

Further, the control microcomputer 40C generates a clock, executes processing based on the generated clock, and performs clock synchronous communication with the drive control microcomputer 50C based on this clock. Is going. Therefore, the control microcomputer 40C transmits the generated clock to the drive control microcomputer 50C.

Then, in the control microcomputer 40C, the respective parts 40a, 40d for setting the target current signal IMS,
The processing in 40 s is repeatedly executed every basic processing time (for control). At this time, the target current signal IMS transmitted from the control microcomputer 40C to the drive control microcomputer 50C is only corrected by inertia control.

The target current setting section 40a will be described.
The target current setting unit 40a has the same configuration as the target current setting unit 40a according to the first embodiment (see FIG. 2),
In the third embodiment, the target current signal IMS is output to the inertia correction unit 40s.

The inertia correction section 40s will be described. The inertia correction unit 40s includes a target current setting unit 40a.
Target current signal IMS from and inertia control unit 40
The inertia control signal from d is input, and the target current signal IMS (after inertia correction) to be transmitted to the drive control microcomputer 50C is output. Inertia correction unit 40s
Then, the inertia control signal is added to the target current signal IMS to calculate the target current signal IMS (after inertia correction).

With reference to FIG. 4, the structure of the driving device 5C according to the third embodiment will be described.

The drive unit 5C is electrically connected to the control unit 4C by the wire harness WH and communicates various signals via the wire harness WH (see FIG. 1). The drive unit 5C includes a one-chip drive control microcomputer 50C, a motor drive circuit 51, and a motor current I / F circuit 5
2, an R / D conversion circuit 53, an output circuit (not shown) for various signals, a storage device (not shown) such as an EEPROM for storing various data used in the drive control microcomputer 50C, and a watchdog timer ( (Not shown) and the like. In addition, in the third embodiment, the drive control microcomputer 50C corresponds to the drive control means described in claim 4.

In the drive unit 5C, the target current signal IMS (after inertia correction) is corrected by damper control based on the electric motor rotation speed signal SMO. Subsequently, in the drive device 5C, various detection signals IMO, PMO are output from the vehicle.
Is taken in, the electric motor control signal VO is set based on the taken-in signals IMO and PMO and the target current signal IMS corrected by the damper control, and the brushless motor 6 is energized.

The drive control microcomputer 50C will be described. The drive control microcomputer 50C uses the electric motor control signal VO.
Current conversion unit 50b and rotation angle conversion unit 50 for setting
c, torque deviation calculator 50d, magnetic field deviation calculator 50
e, torque PI controller 50f, magnetic field PI controller 50
g, a voltage conversion unit 50h, a PWM conversion unit 50i, and a damper control unit 50s and a damper correction unit 50t for correcting the target current signal IMS by damper control.

Further, the drive control microcomputer 50C generates a clock, and the processing is executed based on this clock. The drive control microcomputer 50C performs clock-synchronous communication with the control microcomputer 40C based on the clock transmitted from the control microcomputer 40C.

Then, in the drive control microcomputer 50C,
Each unit 50b-50 for setting the motor control signal VO
i, 50s, 5 for correction by damper control
The processing at 0t is repeatedly executed every basic processing time (for drive control).

The torque deviation calculator 50d will be described. The torque deviation calculator 50d has the same configuration as the torque deviation calculator 50d according to the first embodiment (see FIG. 2), but in the third embodiment, the target current signal IM.
S (after damper correction and after inertia correction) is input from the damper correction unit 50t.

The damper controller 50s will be described. The damper control unit 50s receives the motor rotation speed signal SMO from the rotation angle conversion unit 50c and outputs a damper control signal to the damper correction unit 50t. Since the damper control unit 50s performs the same processing as the damper control unit 40b according to the first embodiment (see FIG. 2), the description thereof will be omitted.

The damper correction unit 50t will be described. The damper correction unit 50t receives the target current signal IMS (after inertia correction) transmitted from the control microcomputer 40C and the damper control signal from the damper control unit 50s, and inputs the target current signal IMS (damper to the damper deviation calculation unit 50d for torque). After correction and after inertia correction) is output. The damper correction unit 50t uses the target current signal IMS (after inertia correction).
The damper control signal is subtracted from the target current signal IMS (after the damper correction and the inertia correction) to calculate the target current signal IMS.

Now, with reference to FIGS. 1 and 4, the operation of the control device 4C and the drive device 5C of the electric power steering device 1 according to the third embodiment will be described.

In the control microcomputer 40C, the target current signal IMS is set based on the steering torque signal T and the vehicle speed signal V for each basic processing time (for control), and the steering torque signal T is set in the target current signal IMS. , Correction by inertia control is performed based on the vehicle speed signal V.

On the other hand, in the drive control microcomputer 50C, the motor rotation speed signal S is output every basic processing time (for drive control).
A damper control signal is generated based on MO, and a target current signal IMS (damper) is added with a damper control correction based on the damper control signal and the target current signal IMS (after inertia correction) transmitted from the control microcomputer 40C. After correction and after inertia correction) is set. Then, in the drive control microcomputer 50C, the target current signal IM from the damper correction unit 50t is set for each basic processing time (for drive control).
S (after damper correction and after inertia correction), motor current signal IMO (digital signal) and motor rotation signal P
Motor control signal VO based on MO (digital signal)
To set.

Then, similarly to the first embodiment, the electric motor drive circuit 51 applies the electric motor voltage VM to the brushless motor 6 by the electric motor control signal VO. Then,
The brushless motor 6 is driven in the forward rotation direction or the reverse rotation direction, and this rotational drive 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 third embodiment, since the drive control microcomputer 50C performs the damper correction, it is not necessary to transmit the motor rotation speed signal SMO from the drive control microcomputer 50C to the control microcomputer 40C. That is, the third
According to the embodiment of the present invention, the damper control can be performed regardless of the reception failure of the signal from the drive control microcomputer 50C in the control microcomputer 40C, and a good steering feeling can be maintained.

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 first embodiment, the control microcomputer and the drive control microcomputer are configured to have the functions of the other microcomputer. However, if the reliability of one of the microcomputers is high, only one of the microcomputers has a high reliability. It may be configured to have the function of the other microcomputer. Alternatively, the configuration of the first embodiment may be added to the configuration of the second embodiment or the configuration of the third embodiment. Further, in the first embodiment, one microcomputer has the main function of the other microcomputer,
When one of the microcomputers fails, the other microcomputer performs the function of the failed microcomputer by reducing the number of processing times, but it is also possible to configure one microcomputer to have only the basic function of the other microcomputer. Well, in this case, the number of times of processing can be increased. For example, the control microcomputer may be configured to have a function of setting a motor control signal by feedforward control, or the drive control microcomputer may be configured to have a function of setting a target current without correction by inertia control or damper control. . Further, in the second embodiment, the drive control microcomputer determines whether or not the target current signal is subjected to the damper correction based on the reception state signal. However, a correction flag is added to the target current signal to control the target current signal. The microcomputer for use may set the correction flag to the presence / absence of damper correction or the like and transmit the correction flag.

[0155]

In the electric power steering apparatus according to the first aspect of the present invention, the drive control means can set the target current signal even when the target current setting means fails to set the target current signal. The control of the brushless motor can be continued only by the means, and the auxiliary steering force can be applied to the steering system.

In the electric power steering apparatus according to the second aspect of the present invention, the target current setting means can set the electric motor control signal even when the drive control means fails to set the electric motor control signal. The control of the brushless motor can be continued only by applying the auxiliary steering force to the steering system.

In the electric power steering apparatus according to the third aspect of the present invention, the drive control means can perform the damper control even when the target current setting means cannot normally receive the motor phase signal and cannot perform the damper control. As a result, the steering feeling does not deteriorate.

In the electric power steering apparatus according to the fourth aspect of the present invention, since the drive control means always performs the damper control, the steering feeling is not deteriorated even when the target current setting means cannot normally receive the motor phase signal. .

[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 first embodiment.

FIG. 3 is a block configuration diagram of a control device and a drive device according to a second embodiment.

FIG. 4 is a block configuration diagram of a control device and a drive device according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device 4, 4A, 4B, 4C ... Control device 5, 5A, 5B, 5C ... Drive device 6 ... Brushless motor (electric motor) 13 ... Electric motor rotation detection means ( Electric motor phase detection means) 40A, 40B, 40C ... Control microcomputer (target current setting means) 50A, 50B, 50C ... Drive control microcomputer (drive control means) 51 ... Electric motor drive circuit (electric motor drive means) ) S ... Steering system TS ... Steering torque sensor (steering torque detecting means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B62D 137: 00 H02P 6/02 321P F term (reference) 3D032 CC35 DA15 DA23 DA63 DA64 3D033 CA03 CA13 CA16 CA20 5H560 AA08 BB04 BB07 BB12 DA02 DB20 DC03 DC04 DC12 DC13 EB01 EB05 EC10 JJ01 SS02 TT15 UA05 XA02 XA04 XA05 XA11 XA12

Claims (4)

[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 comprising a brushless motor, wherein the drive control means fetches a steering torque signal from the steering torque detecting means, and A target current signal can be set based on the steering torque signal when the current setting means fails. And an electric power steering device. 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 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 comprising a brushless motor, wherein the target current setting means fetches an electric motor phase signal from the electric motor phase detecting means, and When the drive control means fails, a motor control signal is set and output to the motor drive means. An electric power steering device characterized in that 3. 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 comprising a brushless motor, wherein the target current setting means fetches an electric motor phase signal from the electric motor phase detecting means, and Damper control is performed based on the electric motor phase signal, and the drive control means,
An electric power steering apparatus, wherein damper control is performed based on the electric motor phase signal when the target current setting means cannot normally receive the electric motor phase signal. 4. 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 comprising a brushless motor, wherein the drive control means performs damper control based on the electric motor phase signal. Electric power steering device