JP3520508B2 - Electric power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Reduces driver steering force by acting directly on the tearing system
The present invention relates to an electric power steering apparatus. [0002] 2. Description of the Related Art An electric power steering device is an electric motor.
Assist the driver's steering force by directly using the driving force of
The However, the electric power steering device is a control means.
Auxiliary torque from the motor, which is undesirable due to abnormalities
If this occurs, the steering force is transferred against the driver's will.
Strike. Therefore, in the electric power steering device,
Detecting unwanted auxiliary torque (motor drive status)
In addition, there is an auxiliary prohibition means that prohibits motor assistance.
There is something Japanese Patent Application Laid-Open No. Hei 11-
59446 includes manual steering torque direction and auxiliary torque.
Drive by electric motor when the direction of
Electric power steering with auxiliary prohibition means to prohibit
An apparatus is described. This electric power steering device
Set the magnitude and direction of the manual steering torque by the driver.
Steering torque sensor to detect and large current flowing to the motor
An electric motor current detecting means for detecting the gap and direction is provided. So
Then, the auxiliary prohibition means detects the direction of the detected manual steering torque
Direction of the current flowing through the detected motor (ie, auxiliary
Torque direction) matches or does not match.
If it continues for more than a certain time, the electric power steering device
Transmits a signal prohibiting driving by an electric motor to the control means
To do. Also, manual steering torque and motor current flow
As well as the direction and magnitude of manual steering torque.
Assistance prohibition due to the relationship between the magnitude and direction of the motor current
Assistance prohibition means to judge by the map where the area is set
There is also an electric power steering device. For example, FIG.
The electric power steering device 50 shown in (a) of FIG.
Steering torque-motor current prohibition area determination as auxiliary prohibition means
Means (hereinafter referred to as determination means) 54 is provided. electric
The power steering device 50 includes a steering torque sensor 51.
CPU (Ce) based on the manual steering torque TS detected in
(Ntral Processing Unit) 53
A target current to be passed through the electric motor 57 is set. In addition, the electric power
The word steering device 50 is the target of the CPU 53.
In order to pass current through the motor 57, the motor drive means 56
A motor control signal to be output is generated. Also electric power
The steering device 50 is powered by the motor current detection means 52.
Detect motor current IM actually flowing through motive 57
The Then, the electric power steering device 50 determines
Means 54 indicates that the driver
The motor current IM, which generates the auxiliary torque that is unintended,
It is determined whether or not the motive 57 is flowing. In the judging means 54
For example, the map 54a shown in FIG.
Search for the relationship between manual steering torque TS and motor current IM
Judgment is made based on whether the area is in the assist-prohibited area 54b or 54c.
The In the map 54a, the horizontal axis represents the steering torque sensor 5.
1 is the manual steering torque TS [kgf · cm] detected in 1.
Positive area indicates right turn and negative area indicates left turn.
The In addition, the vertical axis represents the actual value detected by the motor current detection means 52.
Motor current IM [A] flowing through the motor 57 during
Torque generated in the positive region is the right turn direction, minus region
The torque generated by the region represents the left turning direction. Determination means 54
Searches the map 54a for manual steering torque TS and electric
The relationship of the machine current IM is changed to the assist prohibited areas 54b and 54c.
If it exists, an auxiliary prohibition signal is sent to the switch circuit 55.
I believe. Note that the determination means 54 includes the manual steering torque TS and
The relationship between the motor current IM is the assist prohibited areas 54b and 54
c continuously present for a predetermined time (for example, 100 mS)
In some cases, an auxiliary prohibition signal is transmitted. Subsidy
When the stop signal is transmitted, the switch circuit 55
Is turned off and the motor control signal is output to the motor driving means 56.
do not do. Then, the motor driving means 56 is connected to the motor voltage VM.
Is not applied to the electric motor 57.
Current IM does not flow. Therefore, assistance by electric motor 57
Torque is not generated. The motor current detection means 52
Is a resistor or a host connected in series with the motor 57.
Of the motor current IM flowing through the motor 57
The size and direction are detected. [0004] However, the resistance and
Since the Hall element is affected by temperature, the ambient temperature
Resistance value changes due to changes in temperature and heat generation of the motor 57
To do. Also, resistance and hall elements require processing accuracy.
There are variations in the elements depending on the processing accuracy. But
Thus, the motor current detection means 52 flows to the motor 57
Even if the motor current IM is the same, the ambient environment
Due to temperature changes, heat generation of the motor 57, processing accuracy of elements, etc.
The detected value changes. Therefore, the motor current IM is detected.
The output accuracy decreases, and the map 54a is determined by the determination means 54.
Judgment accuracy decreases. Incidentally, the motor current detection means 5
In order to improve the detection accuracy by 2, temperature compensation circuit etc.
And increase the processing accuracy of resistors and hall elements.
I must. Accordingly, an object of the present invention is to detect the motor current.
Assisted by an electric motor without being affected by output accuracy
Electric power steer that can determine whether or not to prohibit
It is to provide a ring device. [0006] [Means for Solving the Problems]
The electric power steering apparatus according to Ming
An electric motor for adding auxiliary torque to the system, and the steering
Steering torque sensor that detects manual steering torque acting on the system
And the output from the steering torque sensor
Control means for outputting an electric motor control signal for controlling the electric motor
And driving the electric motor based on the electric motor control signal
Motor driving meansThe output of the steering torque sensor
Steering torque differentiation means for differentiating betweenElectric powers with
In the tearing device, the steering torque sensorOutput
The time differential value obtained by the steering torque differential means is added to the value.
Calculated addition valueAnd the motor control signal have a predetermined relationship
The motor is driven by the motor driving means.
A supplemental prohibiting means for prohibiting is provided. this
According to the electric power steering device, generated by the control means
Assist with auxiliary prohibition means using motor control signal to
The motor current is detected.
Highly accurate determination can be made regardless of accuracy.Also, subsidies are prohibited
Manual steering torque and manual steering torque
Taking into account the time variation of the manual steering torque
Judgment is made with consideration. Therefore, the control means
Motor control signal by inertia control considering inertia
Even if is generated, a time change is added to the manual steering torque.
Therefore, it is possible to judge with high accuracy whether or not a predetermined relationship exists.
Can be determined. [0007] It should be noted that the predetermined relationship is the manual steering torque and
The relationship between the motor control signals is contrary to the driver's intention
This is a relationship indicating that the auxiliary torque is generated.
The In the present embodiment, the assist of the map M shown in FIG.
The magnitude and direction of manual steering torque within the prohibited areas Ma, Mb
And duty voltage of PWM signal in motor control signal
This is a case where there is a relationship in which the size and the direction of each are positioned. [0009] DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.
An embodiment of the electric power steering apparatus will be described.
The FIG. 1 is an overall configuration diagram of an electric power steering device,
FIG. 2 shows a control means (steering torque) of the electric power steering device.
Fig. 3 shows the electric power.
FIG. 4 is a logic circuit diagram of the drive control means of the steering device.
Circuit for motor drive means of electric power steering device
FIG. 5 shows auxiliary prohibiting means of the electric power steering apparatus.
6 is a map for searching for an assist-prohibited area. FIG. 6 shows electric power.
-Steering device control means (steering torque differentiation means
It is a block configuration diagram. Electric power steering apparatus according to the present invention
In order to assist the driver's steering force,
Auxiliary torque is generated by the driving force. For that purpose,
The word steering device has control means for controlling the electric motor.
Auxiliary torque is against the driver's intention
Assistance prohibition means to prohibit assist if it is a thing
Prepare. Auxiliary prohibition means include manual steering torque (or hand
(Added value of time differential value of dynamic steering torque and manual steering torque)
And the motor control signal
Determine whether or not In this embodiment,
Such an electric power steering device has an auxiliary in the control means.
It constitutes prohibition means and is supplemented separately from the main CPU of the control means.
A CPU for assistance prohibiting means is provided. In this embodiment,
The control means and auxiliary prohibiting means finely adjust the manual steering torque.
There is no means for dividing and no means for adding the differential value.
Things (see Figure 2)Is shown as a reference example.
For those with steps (see Fig. 6)explain about. First, referring to FIG. 1, an electric power steer
The configuration of the ring device 1 will be described. Electric power steering
The aligning device 1 is a steering wheel by a driver.
Manual steering force generating means 2 is used to manually
The direction of the vehicle by rolling the front wheels 4 and 4 with al steering
change. Furthermore, the electric power steering device 1
An electric motor based on an electric motor control signal VO from the control means 5
The drive means 6 generates an electric motor voltage VM, and this electric motor voltage
Drive the electric motor 7 with the VM to increase the auxiliary steering force (auxiliary torque)
The manual steering force generated by the manual steering force generation means 2 is reduced.
Decrease. The manual steering force generating means 2 is a steering wheel
The connecting shaft is connected to the steering shaft 8 provided integrally with the reel 3.
9 in the steering gearbox 10
The pinion 11a of the rack and pinion mechanism 11 is connected.
The The connecting shaft 9 has universal joints 9a, 9 at both ends.
b. The rack and pinion mechanism 11 is a pinion 1
Rack teeth 11b meshing with 1a are formed on the rack shaft 12.
By engaging the pinion 11a and the rack teeth 11b.
The rotation of the pinion 11a in the lateral direction of the rack shaft 12.
Reinstated movement. Furthermore, the rack shaft 12 has both ends thereof.
Via the tie rods 13, 13, the left and right wheels as rolling wheels
The front wheels 4 and 4 are connected. To generate auxiliary steering force (auxiliary torque)
For this purpose, the electric motor 7 is arranged coaxially with the rack shaft 12.
The The rotation of the electric motor 7 is coaxial with the rack shaft 12.
It is converted into thrust through the ball screw mechanism 14
This thrust acts on the rack shaft 12 (ball screw shaft 14a).
Let The control means 5 includes a vehicle speed sensor 15, a steering torque
Each detection signal of the motor sensor 16 and the motor current detection means 17
V, TS, and IMO are input. And the control means 5
Is based on these detection signals V, TS, and IMO.
Determine the magnitude and direction of the motor current IM flowing through the machine 7,
An electric motor control signal VO is output to the motivation driving means 6. control
The means 5 includes a CPU for performing various calculations and processes, and an input signal variable.
It is composed of conversion means, signal generation means, storage means, and the like. More
In addition, the control means 5 is an auxiliary prohibited hand that performs processing by another CPU.
Stage 30A or auxiliary prohibiting means 30B (see FIGS. 2 and 6)
Is also included in the configuration. Control means 5 includes auxiliary prohibiting means 30A (or
The manual steering torque (automatic
Or manual steering torque and addition of time differential value of manual steering torque.
(Calculation value) and motor control signal VO due to PWM signal
The relationship between the tee voltages is the prohibited area Ma, M of the map M
Within b (see FIG. 5), a predetermined time (for example, 100 mS) or more
If it is continuously present, the auxiliary tor
Prohibit the occurrence of The vehicle speed sensor 15 is a speedometer (not shown).
Not) and detects the speed of the vehicle. And
The vehicle speed sensor 15 is an analog power supply corresponding to the detected vehicle speed.
The vehicle speed signal V of the air signal is transmitted to the control means 5. Car
The speed sensor 15 is connected to the electric power steering device 1 in the vehicle speed.
Not provided only for transmitting signal V, other
The vehicle speed signal V is also transmitted to this system. The steering torque sensor 16 is a steering wheel
It is arranged in the gear box 10 and is manually operated by a driver.
Detect the magnitude and direction of the rudder torque. And steering torque
The sensor 16 corresponds to the detected manual steering torque.
Control means 5 for manual steering torque signal TS of the analog electric signal
Send to. The motor current detecting means 17 is connected to the motor 7.
With a resistor or Hall element connected in series,
The magnitude and direction of the motor current IM that actually flows through the motor 7
Is detected. The electric motor current detection means 17
Control means for motor current signal IMO corresponding to machine current IM
Feedback to 5 (negative feedback). The motor driving means 6 is connected to the motor control signal VO.
The motor voltage VM is applied to the motor 7 based on the
7 is driven. The motor driving means 6 is, for example, shown in FIG.
4 power FETs (field effect transistors)
6a, 6b, 6c, 6d switching element
Consists of ridge circuit and power supply voltage (12v) 6e
The Each gate G of power FET 6a, 6b, 6c, 6d
The motor control signal VO is input to 1, G2, G3 and G4
Then, based on the motor control signal VO, the motor 7
A voltage VM is applied. Then, the electric motor 7 has electric motor electricity.
Current IM flows, and the motor 7 has a torque proportional to the motor current IM.
Luke is generated. The operation of the motor drive means 6
The details will be described later. Next, referring to FIG. 2, the structure of the control means 5A.
The composition will be described. Note that the control means 5A prohibits assistance.
Manual steering torque TS and motor control signal VO by means 30A
From the relationship of the duty voltage by the PWM signal of the motor 7
It is determined whether or not the assist by is prohibited. The control means 5A includes A / D conversion means 20, 2
1A, target current signal setting means 22, deviation calculation means 24,
It comprises drive control means 25 and auxiliary prohibiting means 30A.
It is. The auxiliary prohibiting means 30A is the main part of the control means 5A.
The control means 5A is controlled by a CPU different from the CPU to be
Monitor the main CPU runaway. The A / D conversion means 20 is an FV coordinator (not shown).
Vehicle speed signal input from the vehicle speed sensor 15 via the inverter
No. V is converted from an analog signal to a digital signal.
The digitally converted vehicle speed signal V is used to set the target current signal.
Output to stage 22. The A / D conversion means 21A is a steering torque
The manual steering torque signal TS input from the sensor 16
This is converted from an analog signal to a digital signal.
The obtained manual steering torque signal TS is used as the target current signal setting means 2.
2 and the prohibited area determination means 31A. The target current signal setting means 22 is a ROM (R
storage means such as “Ead Only Memory”
Manual operation set in advance based on experimental or design values.
Rudder torque signal TS, vehicle speed signal V and target current signal IM
Data corresponding to S is stored. And target current
The signal setting means 22 includes a manual steering torque signal TS and a vehicle
Target current signal IMS corresponding to the speed signal V as an address
And the target current signal IMS is sent to the deviation calculating means 24.
Output. Incidentally, the target current signal IMS is a vehicle speed signal.
Large value for low speed with large road reaction force against V
Is associated with high speed to ensure stability during driving
In the case of, a small value is associated. Also target
The current signal IMS is relative to the manual steering torque signal TS.
When the manual steering torque signal TS is near 0, it is associated with 0.
If it exceeds the predetermined manual steering torque signal TS,
Corresponds to the value that increases as the rudder torque signal TS increases
It is done. The target current signal IMS is supplied to the electric motor 7.
Since the maximum current that can be
Set below the current. The deviation calculating means 24 is a subtractor or software.
A control subtraction function is provided, and from the target current signal setting means 22
Target current signal IMS and the motor current detection means 17
An electric motor current signal IMO is input, and the drive control means 25
Deviation signal ΔIM is output. The deviation calculation means 24 is a target
Subtract the motor current signal IMO from the current signal IMS
The difference signal ΔIM (= IMS−IMO) is calculated. The drive control means 25 is a PID controller.
, PWM signal generation means, logic circuit, etc., deviation
The deviation signal ΔIM from the calculation means 24 is input, and the electric motor
The prohibited area size is determined via the driving means 6 and the CR filter 35.
The motor control signal VO is output to the fixing means 31A. Drive system
First, the control means 25 adds P (proportional), I to the deviation signal ΔIM.
(Integration) and D (differentiation) control, and deviation signal
PWM signal VPW corresponding to the magnitude and polarity of ΔIM
M, an on signal VON, and an off signal VOF are generated. PW
The M signal VPWM is the power FET 6 of the motor driving means 6.
a gate G1 of a or gate G2 of power FET 6b
Input (see FIGS. 3 and 4), the magnitude of the deviation signal ΔIM
Depending on the power FET 6a or power FET 6b
This is a signal for WM driving. Note that the PWM signal VPWM is
Input to either gate G1 or gate G2
This is determined by the polarity of the deviation signal ΔIM. Also,
PWM signal VPWM of gate G1 or gate G2
The off signal VOF is input to the gate that is not input, and
The word FET 6a or the power FET 6b is turned off.
The PWM signal VPWM is input to the gate G1.
In this case, the ON signal V is applied to the gate G4 of the power FET 6d.
ON is input, and the power FET 6d is turned on.
On the other hand, when the PWM signal VPWM is input to the gate G2.
In this case, the ON signal VO is applied to the gate G3 of the power FET 6c.
N is input and the power FET 6c is turned on. Further, the drive control means 25 includes a logic circuit.
Prepared, the auxiliary prohibiting signal SB from the auxiliary prohibiting means 30A is input.
Motor drive means according to the auxiliary prohibition signal SB
6 outputs an electric motor control signal VO. Auxiliary prohibition signal SB
Is a signal that permits assist by the electric motor 7, drive
The control means 25 uses the deviation signal Δ as the motor control signal VO.
PWM signal VPW corresponding to the magnitude and polarity of IM
M, an ON signal VON, and an OFF signal VOF are assigned to each gate G1,
Output to G2, G3, G4 (see FIGS. 3 and 4). other
On the other hand, the auxiliary prohibition signal SB prohibits the assist by the electric motor 7.
In the case of a signal to be driven, the drive control means 25 is a motor control signal
As the VO, the off signal VOF is sent to all the gates G1, G2,
Output to G3 and G4 (see FIGS. 3 and 4). The auxiliary prohibiting means 30A is prohibited area determining means.
31A, time measuring means 32, predetermined time setting means 33, time ratio
Comparing means 34 and CR filter 35 are included. Supplement
Assistance prohibiting means 30A is used to control the CPU 5A
Therefore, to prohibit the motor 7 from being abnormally driven
In addition, the motor control signal V with reference to the manual steering torque TS
Duty voltage VD is monitored by O PWM signal VPWM
Look. Incidentally, the motor control signal VO is played by the CPU.
Because it is calculated and generated, the ambient temperature and the
Does not fluctuate due to heat. The prohibited area judging means 31A is a memory such as a ROM.
Pre-set based on experimental or design values
Manual steering torque TS and motor control signal VO PWM
A graph showing the relationship of the duty voltage VD by the signal VPWM.
(See FIG. 5). Prohibited area determination means
31A is a manual steering torque from the A / D conversion means 21A.
PWM signal VPWM from signal TS and CR filter 35
Duty voltage VD is input and the prohibited region determination signal S is input.
A is output to the timing means 32. PWM signal VPW
The duty voltage VD of M is electrically driven from the motor driving means 6.
The voltage corresponding to the motor voltage VM applied to the machine 7
The The map used in the prohibited area determination means 31A.
Is a map M shown in FIG. Map M has horizontal axis
Manual steering torque TS detected by the steering torque sensor 16
[Kgf · cm], the vertical axis from the CR filter 35
Duty voltage VD of the output PWM signal VPWM
[V]. Positive range of manual steering torque TS (horizontal axis
The right side of the origin (0) of the steering wheel 3
Corresponding to manual steering torque input in the right turn direction
Negative region of manual steering torque TS (the origin of the horizontal axis
(Left area of (0)) turns left on the steering wheel 3
This corresponds to the case where the direction manual steering torque is input. Ma
In addition, the duty voltage VD of the PWM signal VPWM is plus
In the area (the area above the origin (0) on the vertical axis), the motor 7 turns clockwise.
Corresponding to the output of torque in the rotational direction, PWM signal V
Negative region of PWM duty voltage VD (vertical axis
The lower area of the point (0) is the torque of the motor 7 in the left turn direction.
This corresponds to the case of outputting. Map M assist prohibited
The areas Ma and Mb are desirable for the manual steering torque TS.
In the range of duty voltage VD of PWM signal VPWM not
There are damping control and inertia for the motor 7
Considering the control, it is an area that can be entered during actual driving.
The fixed time is an allowable area. The prohibited area determination means 31A detects the map M.
Search for the manual steering torque TS and the PWM signal VPWM
The relationship of the tie voltage VD is the assist prohibited area M of the map M
Forbidden area determination if in either a or Mb area
Set logic level 0 as signal SA and disable assist
When it is outside the areas Ma and Mb, the prohibited area determination signal SA is used.
Set logic level 1. Logic of prohibited area determination signal SA
The setting of the level is not limited to the above setting, but the time measuring means 32
It is set according to the configuration of the logic circuit. The time measuring means 32 is provided with a timer and is prohibited.
The prohibited area determination signal SA from the determination means 31A is input.
Then, the time measuring signal TC is output to the time comparing means 34. Timing
The means 32 measures the time counter when the prohibited area determination signal SA becomes 0.
Start measurement and output the measured time as a time signal TC
The In addition, the time counting means 32 has a prohibited area determination signal SA of 1.
When it becomes, the measured time is reset. The predetermined time setting means 33 is a memory such as a ROM.
Means, and an allowable time T for the assist prohibited areas Ma and Mb
1 (for example, 100 mS) is output to the time comparison means 34.
The In addition, the allowable time T1 is the manual steering torque TS and PW.
The relationship of duty voltage VD of M signal VPWM is map M
Is in one of the prohibited areas Ma and Mb
In this case, it is time to allow assist by the electric motor 7. The time comparing means 34 is supplied from the time measuring means 32.
Time keeping signal TC and allowable time T from predetermined time setting means 33
1 is input and the auxiliary prohibition signal SB is sent to the drive control means 25.
Output. The time comparison means 34 indicates that the time signal TC is acceptable.
When T1 or higher, the auxiliary prohibition signal SB is at a logic level
When 1 is set and the time signal TC is less than the allowable time T1
Sets a logic level 0 as the auxiliary inhibit signal SB. You
That is, when the timing signal TC is equal to or greater than the allowable time T1,
The auxiliary prohibiting means 30A determines that the control means 5A is abnormal,
Assist by the electric motor 7 is prohibited. In addition, assistance prohibition signal
The logic level setting of the number SB is not limited to the above setting,
Set according to the configuration of the logic circuit of the drive control means 25
The The CR filter 35 has a slow time constant CR filter.
The motor control from the drive control means 25 is provided with a filter circuit
When the signal VO is input, the duty of the PWM signal VPWM
The voltage VD is output to the prohibited area determination unit 31A. CR
The filter 35 is a PWM signal VPW of the motor control signal VO.
Converts the duty ratio of M to voltage level and
Determine the direction in which the voltage is applied and
An application direction is identified by adding eggplant. For example, power supply voltage
Is 12V, and the duty ratio of the PWM signal VPWM is 7
(Logical level 1): 3 (logical level 0), 1
2V × (7/10) = 8.4V is the PWM signal VPWM
It becomes the duty voltage VD. Also, this PWM signal VP
The duty voltage VD of WM is on the right of map M (see Fig. 5)
Turn direction (positive area of the vertical axis) or left turn direction (vertical axis
Of the PWM signal VPWM.
Is either gate G1 or gate G2 (see FIG. 3)
It depends on whether it is output to the gate. For example, to gate G1
In the case of the output PWM signal VPWM, turn right
(Plus region on the vertical axis) and P output to the gate G2
In the case of the WM signal VPWM, the counterclockwise turning direction (the minor axis on the vertical axis)
Area). The auxiliary prohibiting means 30A has a manual steering torque T
The relationship between S and the duty voltage VD of the PWM signal VPWM is
Assist prohibited area Ma, Mb of map M
If the area continues for the allowable time T1 or longer, the control means 5A
Is determined to be abnormal. And the auxiliary prohibiting means 30A
Is supplied to the drive control means 25 as an auxiliary prohibition signal SB.
Bell 1 is output to urge the motor 7 to stop driving. Drive system
The control means 25 has a logic level 1 as the auxiliary prohibition signal SB.
When input, the off signal VO as the motor control signal VO
F is output to all gates G1, G2, G3, G4
(See FIGS. 3 and 4). Then, the electric motor driving means 6
Since the motor voltage VM to the motive 7 becomes 0V, the motor 7
Is not driven and does not generate auxiliary torque. Next, referring to FIG. 6, the structure of the control means 5B.
The composition will be described. Note that the control means 5B prohibits assistance.
Manual steering torque TS to manual steering torque TS by means 30B
Of the motor control signal VO
Is it related to duty voltage VD by PWM signal VPWM?
To determine whether to prohibit the assist by the electric motor 7
The The control means 5B controls the inertia of the electric motor 7.
For example, inertia control is performed. Tsuma
Thus, the electric motor 7 is rotated from forward rotation to reverse rotation or from reverse rotation to forward rotation.
When switching between rotation and rotation direction, change the direction of voltage application.
Even if it is changed, the direction of rotation is immediately switched by the inertia of the motor.
It does not change. Therefore, in the control means 5B, the inertia
Switching of the rotation direction of the electric motor 7 is manual by control.
The timing at which the turning direction of the steering torque TS changes
It is controlled to match. For example, the control means 5B
The absolute value of manual steering torque TS for turning right is small and turning right
If the manual steering torque TS is reduced, turn left
A motor control signal VO that generates auxiliary torque
To do. Then, the manual steering torque TS is still turning right
Regardless, the electric motor drive means 6 is connected to the electric motor 7 in the left turning direction.
The motor voltage VM for generating the auxiliary torque is applied.
Therefore, for example, in the map M of FIG.
Direction of the right hand steering torque TS is small and turns right
Manual steering torque with reduced manual steering torque TS
For TS1, the motor control signal VO compensates for the left turn direction.
PWM signal generated as a signal to generate auxiliary torque
VPWM duty voltage VD is VD1 (negative value)
It becomes. As a result, manual steering despite the correct control
Duty voltage V of torque TS1 and PWM signal VPWM
The intersection point a of D1 is located in the assist prohibition area Ma.
Therefore, the auxiliary prohibiting means 30B is manually operated as the value on the horizontal axis.
Add time differential value of manual steering torque TS to rudder torque TS
By determining the assist prohibited areas Ma and Mb.
Therefore, it is generated in consideration of the inertia control of the electric motor 7 etc.
Corresponds to the motor control signal VO. The control means 5B includes A / D conversion means 20, 2
1B, target current signal setting means 22, deviation calculation means 24,
It comprises drive control means 25 and auxiliary prohibiting means 30B.
It is. The auxiliary prohibiting means 30B is a main part of the control means 5B.
The control means 5B is controlled by a CPU different from the CPU to be
Monitor the main CPU runaway. Control means
5B is the same code | symbol to the component same as the control means 5A.
The description is omitted. The A / D conversion means 21B is connected to the control means 5A.
It is the same A / D conversion means as the A / D conversion means 21A.
Converts the converted manual steering torque signal TS to the target current signal.
Setting means 22, steering torque differentiating means 36, and adding means
To 37. The auxiliary prohibiting means 30B is a prohibited area determining means.
31B, time measuring means 32, predetermined time setting means 33, time ratio
Comparison means 34, CR filter 35, and steering torque differentiator
It comprises a stage 36 and an adding means 37. Assistance prohibited hand
The stage 30B is powered by the runaway of the CPU of the control means 5B.
In order to prohibit the motive 7 from being abnormally driven,
Add time differential value of manual steering torque TS to rudder torque TS
The PWM signal of the motor control signal VO based on the added value
The duty voltage VD by the signal VPWM is monitored. China
The motor control signal VO is generated by calculation by the CPU.
Therefore, depending on the ambient temperature and the heat generated by the motor 7, etc.
Does not fluctuate. The steering torque differentiating means 36 is a differentiator or
Has a software-controlled differential function, A / D conversion means 21B
The manual steering torque signal TS is input to the adding means 37.
To output a manual steering torque time differential value dTS / dt.
The steering torque differentiating means 36 calculates the manual steering torque TS over time.
Differentiate and calculate manual steering torque time differential value dTS / dt
To do. Manual steering torque time differential value dTS / dt
Indicates that the manual steering torque TS is a clockwise torque,
When the rotational torque increases, it becomes a positive value and turns right
A negative value is obtained when the rotational torque is decreasing. Ma
The manual steering torque time differential value dTS / dt
The rudder torque TS is the left turn torque, and the left turn torque is
If it increases, it becomes a positive value, and the left turn torque is
When it is decreasing, it becomes a negative value. The adding means 37 is an adder or software control.
Addition function and manual operation from the A / D conversion means 21B
Manual control from steering torque signal TS and steering torque differentiation means 36
Steering torque time differential value dTS / dt is input and prohibited
The added value is output to the area determination means 31B. Addition means 37
Is the manual steering torque TS and the manual steering torque time differential value d
Add TS / dt and add value (= TS + dTS / dt)
Is calculated. Therefore, the added value is the manual steering torque T
S is the right turn torque and the right turn torque is increasing
In the case of
Manual steering torque T when right turn torque is decreasing
The value is smaller than S. Also, the added value is
Luk TS is left turn torque, left turn torque increases
If the value is higher than the manual steering torque TS,
If the left turn torque is decreasing, manual steering torque
The value is smaller than the value of Luk TS. The prohibited area determination means 31B is a memory such as a ROM.
Pre-set based on experimental or design values
Manual steering torque TS and manual steering torque time differential value d
Addition value of TS / dt and PWM signal of motor control signal VO
A map showing the relationship of duty voltage VD by signal VPWM
Is stored. The prohibited area determination means 31B adds
Addition value (= TS + dTS / dt) from means 37 and CR
Duty power of PWM signal VPWM from filter 35
The pressure VD is inputted, and the prohibited area determination signal SA is measured by the time measuring means 3
Output to 2. The duty of the PWM signal VPWM
The voltage VD is applied from the motor driving means 6 to the motor 7.
This is a voltage corresponding to the motor voltage VM. Also, prohibited areas
The map used in the area determination means 31B is a prohibited area determination
Same as map M (see Fig. 5) used in step 31A
Is used. The prohibited area judging means 31B adds the added value (= T
S + dTS / dt) and duty of PWM signal VPWM
The map M is searched with the voltage VD. For this search, map
Addition value (== manual steering torque TS which is the horizontal axis of M)
TS + dTS / dt) is applied. And the prohibited area size
The determining means 31B uses the added value (= TS + dTS / dt) and P
The relationship of duty voltage VD of WM signal VPWM is a map
In either of the M prohibited areas Ma and Mb
If this is the case, the logic level 0 is set as the prohibited area determination signal SA.
Set and prohibited when outside the assist prohibited areas Ma and Mb
A logic level 1 is set as the area determination signal SA. That is, in the prohibited area judging means 31A, the horizontal
The manual steering torque TS was applied as it was as the shaft value.
However, in the prohibited area determination means 31B, manual operation is performed as the value of the horizontal axis.
The steering torque TS is a time differential value of the manual steering torque TS.
A value obtained by adding dTS / dt is applied. Therefore,
Manual steering torque TS decreases for the horizontal axis of map M
Manual steering torque T
The map M is searched with the prefetched value of S over time.
It will be. For example, as shown in FIG.
TS1 is right turn torque and manual steering torque TS
When 1 is decreasing, the time derivative dTS1 / dt is
Inus value. Therefore, the added value (= TS1 + dT
S1 / dt) is smaller than the manual steering torque TS1.
Become. As described above, the manual steering torque TS1
Duty voltage of PWM signal VPWM generated for
VD is VD1 (negative value).
Dynamic steering torque TS1 and PWM signal duty voltage VD1
Is located in the assist prohibition area Ma. Only
Then, the horizontal axis is mapped with the added value (= TS1 + dTS1 / dt).
Search, the added value (= TS1 + dTS1 / dt) and
Assistance prohibited at intersection b of PWM signal duty voltage VD1
Located outside the stop region Ma. Therefore, prohibited area determination means
31B sets logic level 1 as the prohibited area determination signal SA.
Set. Therefore, the prohibited area judging means 31B
In response to switching of the turning direction of the manual steering torque TS
To switch the rotation direction of the electric motor 7 in a timely manner
A manual steering torque is generated with respect to the generated motor control signal VO.
High accuracy by adding time change to the TS
A map search can be performed. Control means 5A and 5B and auxiliary prohibition
The means 30A and 30B may be constituted by analog circuits.
Yes. Here, the electric motor is activated by the auxiliary prohibition signal SB.
Electric power steering for which assistance by 7 is prohibited
In order to explain the operation of the device 1, the theory of the drive control means 25
The circuit of the logic circuit and the motor driving means 6 will be described.
The First, referring to FIG. 3, the drive control means 25.
The configuration of the logic circuit 25a will be described. Logic circuit 2
5a is a logical circuit comprising a NOT gate and a logical product operation means.
Routes 25b, 25c, 25d, and 25e are provided. Each NOT
Gates 25f, 25g, 25h, 25i are prohibited from assistance
Time comparison means of stage 30A (or auxiliary prohibiting means 30B)
The auxiliary prohibition signal SB from 34 is input and the logical product operator
Auxiliary prohibition signal SB at stages 25j, 25k, 25l, 25m
The logic level of is inverted. Each AND operation means 25
j, 25k, 25l, and 25m are the NOT gates 25, respectively.
f, 25g, 25h, 25i output and PWM signal VPW
M, ON signal VON or OFF signal VOF is input,
Each gate G1, power FET 6a, 6b, 6c, 6d
The motor control signal VO is output to G2, G3 and G4. each
AND operation means 25j, 25k, 25l, 25m are N
The output of the OT gates 25f, 25g, 25h, 25i is 0
(That is, at the logic level 1 of the auxiliary prohibition signal SB)
When assisting the motor 7 is prohibited)
Bell 0 (off signal VOF) is output. On the other hand, each AND
The calculation means 25j, 25k, 25l and 25m are NOT
When the output of the ports 25f, 25g, 25h, 25i is 1
(In other words, the motor at the logic level 0 of the auxiliary prohibition signal SB
7), the input PWM
Signal VPWM, ON signal VON or OFF signal VOF
Output as is. The motor control signal VO is a logical signal.
Output from product calculation means 25j, 25k, 25l, 25m
PWM signal VPWM, ON signal VON and OFF signal
No. VOF and the duty ratio of the PWM signal VPWM
Determine the motor voltage VM, turn on signal VON and off signal V
The rotation direction of the electric motor 7 is determined by OF. Next, referring to FIG. 4, the motor driving means 6
The configuration of the circuit will be described. The motor driving means 6
Bridge with 4 power FETs 6a, 6b, 6c, 6d
A circuit is configured and a power supply voltage 6e to 12v is supplied.
Is done. Further, the motor driving means 6 is configured so that the motor 7 is powered.
-Between the FET 6a and the power FET 6d in series and power
-Connected in series between FET 6b and power FET 6c
The The power FETs 6a and 6b are connected to the gates G1 and G2, respectively.
PWM signal VPWM or OFF signal VOF is input,
Off when the PWM signal VPWM is input and the logic level is 1.
To do. The power FETs 6c and 6d have gates G3 and G
4 is supplied with an ON signal VON or an OFF signal VOF,
Turns on when the on signal VON is input. Electric
The motor voltage VM applied to the machine 7 is the PWM signal VPW
It is determined by the duty ratio of M. And electric motor
7 corresponds to the motor voltage VM.
Value. For example, the duty of the PWM signal VPWM
If the ratio is 7 (logic level 1): 3 (logic level 0),
12V × (7/10) = 8.4V is the motor voltage VM
That is, 8.4V is continuously applied to the electric motor 7.
become. Now, referring to FIG. 3 and FIG.
Assistance prohibition means 30A (or assistance prohibition means 30B) assists
When the inhibit signal SB is output as a logic level 0
The operation of the electric power steering device 1 will be described.
The The steering wheel 3 is driven by the driver.
Is operating clockwise (turn the vehicle to the right
The input terminal of the AND operation means 25j
The PWM signal VPWM is input, and the logical product calculating means 25
The off signal VOF is input to the input terminals of k and 25l,
The ON signal VON is input to the input terminal of the AND operation means 25m.
Is done. At this time, the auxiliary prohibition means 30A (or auxiliary prohibition)
The auxiliary inhibit signal SB from the means 30B) is logic level 0.
(I.e., assist by the motor 7 is permitted)
Are each AND operation means 25j, 25k, 25l, 25m
Is the input PWM signal VPWM, ON signal VON
Alternatively, the same signal as the off signal VOF is applied to each gate G1, G2, and so on.
Output to G3 and G4. Then, the power FET 6a is
PWM signal VPWM is input to the motor G1 and PWM drive is performed
The power FETs 6b and 6c are connected to the gates G2 and G3, respectively.
OFF signal VOF is input and the power FET 6d is turned off.
An ON signal VON is input to the gate G4 to drive it ON
The Then, the motor current IM is changed from the power supply voltage 6e to the power.
FET 6a → motor 7 → power FET 6d → GND 6f
(In the direction of the arrow in FIG. 4). As a result, the electric motor
7 is, for example, an auxiliary truck that rotates forward and the vehicle turns to the right.
Luke is generated. On the other hand, the steering wheel is driven by the driver.
3 is operated counterclockwise (turn the vehicle counterclockwise
If it is going to turn), the logical product calculation means 25k input
The PWM signal VPWM is input to the power terminal and the logical product operator
The off signal VOF is input to the input terminals of the stages 25j and 25m.
The ON signal VON is input to the input terminal of the AND operation means 25l.
Is entered. At this time, the auxiliary prohibiting means 30A (or the auxiliary
The auxiliary prohibiting signal SB from the auxiliary prohibiting means 30B)
Le 0 (that is, assistance by the motor 7 is permitted)
In this case, each AND operation means 25j, 25k, 25l, 2
5m is the input PWM signal VPWM, ON signal VO
N or the same signal as the OFF signal VOF is applied to each gate G1, G
2, output to G3, G4. Then, power FET6b
PWM signal VPWM is input to gate G2 and PWM
The power FETs 6a and 6d are driven by the gates G1 and G4.
Is turned off when the OFF signal VOF is input to the power FET 6
c is turned on when the ON signal VON is input to the gate G3.
To do. Then, the motor current IM is changed to the power supply voltage 6e → power
-FET 6b-> Motor 7-> Power FET 6c-> GND 6
It flows through the path f. As a result, the electric motor 7 rotates in the reverse direction,
An auxiliary torque for turning the vehicle to the left is generated. Next, referring to FIG. 3 and FIG.
Stop means 30A (or auxiliary prohibiting means 30B) prohibits auxiliary
Electricity when signal SB is output as logic level 1
The operation of the power steering device 1 will be described. As described above, the control means 5 (5A, 5B)
Assistance prohibition means 30A (also
The auxiliary prohibiting means 30B) is considered as the auxiliary prohibiting signal SB.
Level 1 (ie, assistance by motor 7 is prohibited)
May be output. In this case, all conjunctions
The calculation means 25j, 25k, 25l, 25m
Level 25f, 25g, 25h, 25i to logic level 0
Is input to a logic level 0 (ie, an off signal
VOF) is output to each gate G1, G2, G3, G4.
The Then, the power FETs 6a, 6b, 6c, 6d
Turn off all. As a result, the motor voltage VM is applied to the motor 7.
Not applied. Therefore, the motor current IM is equal to the motor 7
Therefore, the motor 7 is not rotated and the auxiliary torque is not
No problem occurs. According to the electric power steering apparatus 1
For example, an electric motor whose detection accuracy decreases due to the ambient temperature
The motor control signal VO is used without using the current IM.
Whether to prohibit the assist by the electric motor 7 or not.
Can be determined at any time. The motor control signal VO
Is generated by computing with the CPU, so the ambient temperature, etc.
Is not affected by Furthermore, electric power steering device
1 is an electric motor control by inertia control etc. by the control means 5
Even if the control signal VO is generated, the auxiliary prohibiting means 30B
Therefore, taking into account the time differential value of the manual steering torque TS
Thus, a map search can be performed with high accuracy. As described above, the present invention is limited to the above embodiment.
Without being done, it is implemented in various forms. For example, forbidden
A map M shown in FIG.
Used, but not limited to this map,
Various controls for setting the current and steering requests from external systems
You may set suitably according to a signal etc. In a predetermined time
A certain allowable time T1 is set to 100 ms, but other time
Or set according to the manual steering torque TS
The time T1 may be variable. In addition, when a predetermined time
If you are in the assist-prohibited area without comparing
As a configuration that immediately prohibits assistance by electric motor
Also good. The PWM signal V is used as the motor control signal VO.
It consists of PWM, ON signal VON, OFF signal VOF
This is especially true for motor control signals that control the drive of the motor.
It is not limited to these three signals. [0058] According to the first aspect of the present invention, there is provided an electric power station.
The aligning device outputs the motor control signal generated by the control means.
Judgment whether or not to prohibit assistance by means of assistance prohibition
High accuracy, regardless of the motor current detection accuracy.
Judgment can be made.In addition, when judging with auxiliary prohibition means
In addition, the time differential value of the manual operation torque is added to the manual steering torque.
The determination is made in consideration of the time change of the manual steering torque.
Therefore, the electric power steering device is a control means.
The motor control signal is generated taking into account the inertia of the motor.
Even if it is, it is determined with high accuracy whether or not it is in a predetermined relationship.
Can. [0059]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of an electric power steering apparatus according to an embodiment. FIG. 2 is a block configuration diagram of control means (without steering torque differentiating means) of the electric power steering apparatus according to the reference example . FIG. 3 is a logic circuit diagram of drive control means of the electric power steering apparatus according to the present embodiment. FIG. 4 is a circuit diagram of electric motor driving means of the electric power steering apparatus according to the present embodiment. FIG. 5 is a map for searching for an assist prohibition region by an auxiliary prohibition unit of the electric power steering apparatus according to the present embodiment; FIG. 6 is a block configuration diagram of control means (with steering torque differentiating means) of the electric power steering apparatus according to the present embodiment. 7A is a schematic configuration diagram of a control unit in a conventional electric power steering apparatus, and FIG. 7B is a map for searching for an assist prohibition region by an auxiliary prohibition unit. DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus 5, 5A, 5B ... Control means 6 ... Electric motor drive means 7 ... Electric motor 16 ... Steering torque sensors 30A, 30B ... Auxiliary prohibition Means 36 ... Steering torque differentiation means

─────────────────────────────────────────────────── ─── Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B62D 6/00 B62D 5/04

Claims (1)

(57) Claims 1. An electric motor for adding auxiliary torque to a steering system, a steering torque sensor for detecting a manual steering torque acting on the steering system, and an output from the steering torque sensor Control means for outputting an electric motor control signal for controlling the electric motor based on the electric motor, electric motor driving means for driving the electric motor based on the electric motor control signal, and the operation
Steering torque differential hand that differentiates the output of the rudder torque sensor with time
An electric power steering apparatus comprising: a steering torque differential sensor; and an output value of the steering torque sensor.
An auxiliary prohibiting means for prohibiting driving of the electric motor by the electric motor driving means when the added value obtained by adding the time differential values obtained in the stage and the electric motor control signal have a predetermined relationship; Power steering device.