JP4899677B2 - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device in which the steering feeling is not abruptly changed, and the steering feeling is not impaired even when a steering angle or a steering angle estimation signal cannot be outputted by occurrence of abnormality. <P>SOLUTION: A control unit 30 of the electric power steering device has a signal storage unit 52a which calculates steering information on the steering angle signal &theta;<SB>H</SB>detected by a steering angle sensor 15 and stores the steering angle information. When a steering angle sensor abnormality detection unit 50 detects occurrence of abnormality of the steering angle sensor 15, a motor 20 is controlled to be continuously operated based on steering angle information immediately before the occurrence of abnormality recorded in the signal recording unit 52a, and the motor angle signal &theta;<SB>M</SB>. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a control device for an electric power steering device that applies an auxiliary torque by a motor to a steering system of a vehicle.

  In an electric power steering device used in a conventional vehicle, a steering torque input by a steering wheel is detected by a torque sensor, an auxiliary torque corresponding to the steering torque is obtained by a motor, and an auxiliary torque is applied to the steering, and steering is performed. Control is performed to reduce the steering force input by the user. In addition to such control, the electric power steering device also detects the external environment surrounding the vehicle, such as the speed and steering angle of the vehicle, and controls to improve the steering feeling of the steering based on these detection results. Has also been implemented. In particular, the steering angle is used for, for example, steering wheel return control, and the steering wheel return control has a function of adding auxiliary torque in the steering wheel return direction according to the steering angle.

  Thus, the steering angle is a signal mainly used for control for improving the steering feeling in the electric power steering apparatus, and the steering angle detection device for detecting the steering angle or the steering angle is estimated with respect to the steering angle. Various methods for detecting an abnormality in a signal processing apparatus and countermeasures against this abnormality are known (see, for example, Patent Documents 1, 2, 3, and 4).

  In Patent Document 1, a value (relative rudder angle value) output by a rudder angle sensor, which is a rudder angle detecting means, is predetermined in order to detect an abnormality such as a disconnection or a failure in a device related to detection or calculation processing of the rudder angle. A configuration is shown in which it is determined whether the value is within the predetermined range, and if the value is not within the predetermined range, the value is determined to be abnormal.

  Moreover, in patent document 2, when sensors, such as a steering angle detection apparatus which detects the steering angle signal input into a steering wheel return control part, abnormality generate | occur | produces by disconnection etc., this abnormality is detected and steering wheel return control is performed. What to disable is shown.

  Furthermore, in Patent Document 3, when the deviation between the rotation angle of the motor and the steering angle is equal to or greater than the comparison reference value, an abnormality is diagnosed, and when the abnormality is determined, the use of the steering angle for the motor current control is used. Only the immediate prohibition is shown. In addition, when the steering angle is always stored and it is determined that there is an abnormality, the previous steering angle stored immediately before the abnormality is determined is used for controlling the motor current, and the previous steering angle is gradually decreased. A configuration is also shown in which the influence on the control of the motor current is gradually reduced.

Further, in Patent Document 4, at least three rudder angle sensors each having a different phase according to a rudder angle change are attached to a vehicle, and a rudder that detects an abnormality of the steering sensor from each output state of the rudder angle sensor is disclosed. An angle detector is shown.
JP-A-8-54229 JP 2003-291842 A JP 2003-252228 A JP-A-10-274520

  However, in the electric power steering devices described in Patent Documents 1 to 3, when it is determined that an abnormality has occurred in the device related to detection of the steering angle, a part of the control is stopped, and the vehicle is running The steering feeling of the steering wheel changes suddenly due to the stop, and there is a concern that the steering wheel cannot respond to it and the vehicle becomes unstable, and the function of the control system is reduced. There was a problem that the steering feeling was lost. In particular, Patent Document 3 discloses a configuration in which the steering angle is stored and the change is gradually performed using the steering angle immediately before the abnormality determination, but as a result, the steering feeling is impaired. There is no change in the state, and the steering feeling loss is not suppressed.

  Moreover, in patent document 4, although it is the structure which attaches a some steering angle sensor and detects abnormality, there existed a problem that a structure will become complicated and cost will become high.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to make it impossible to output a steering angle or a steering angle estimation signal due to an abnormality in the steering angle detection means or the steering angle estimation means with a simple configuration. Therefore, an object of the present invention is to provide an electric power steering apparatus capable of suppressing steering feeling loss without causing a sudden change in steering feeling.

The above object of the present invention can be achieved by the following constitution.
(1) Steering angle detection means for detecting the steering angle of the steering, a steering control drive device for controlling the motor to apply auxiliary torque to the steering, an abnormality detection means for determining an abnormality of the steering angle detection means, In an electric power steering apparatus comprising motor angle detection means for detecting a rotation angle of the motor,
The steering control drive device calculates steering angle information related to the steering angle signal detected by the steering angle detection means,
Comprising signal storage means for storing the rudder angle information,
When the abnormality detection means detects the abnormality occurrence of the rudder angle detection means,
And the steering angle information of the abnormality occurrence immediately before recorded in the signal SL 憶 means, on the basis of the motor angle signal detected by the motor angle detecting means,
An electric power steering apparatus characterized in that the motor is continuously operated while being controlled.

(2) In the electric power steering device according to (1),
The electric power steering apparatus according to claim 1, wherein the steering angle information is a steering angle midpoint signal calculated from the steering angle signal and the motor angle signal.

(3) In the electric power steering device according to (1) or (2),
The steering control drive device includes signal calculation processing means for calculating an average value of the steering information stored in the signal storage means for a predetermined time,
When the abnormality detection means detects the abnormality occurrence of the rudder angle detection means,
Based on the calculation result of the signal arithmetic processing means,
An electric power steering apparatus characterized in that the motor is continuously operated while being controlled.

The electric power steering system according to any one of (4) (1) (3),
The steering control drive device until the vehicle stops or until the abnormality detection means determines that the signal has returned to the normal state from the occurrence of the abnormality.
An electric power steering apparatus characterized in that the motor is continuously operated while being controlled.

  According to the present invention, even when an abnormality occurs in the rudder angle detection means or the rudder angle estimation means and the signal of the rudder angle or the rudder angle estimation signal is not output with a simple configuration, immediately before the abnormality occurs. Since these signals are stored and the motor is controlled and operated until the vehicle stops or the steering angle detection means or the steering angle estimation means recovers based on the signals, the steering feeling changes rapidly. Steering that can suppress the steering feeling loss without performing the operation can be realized.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration of an electric power steering apparatus according to the present embodiment. FIG. 2 is a block configuration diagram showing the flow of assist control of the control unit 30.

In the electric power steering apparatus, as shown in FIG. 1, the column shaft 2 of the steering handle 1 is coupled to a tie rod 6 of the steering wheel via a reduction gear 3, universal joints 4 a and 4 b, and a pinion rack mechanism 5. . The column shaft 2 is provided with a torque sensor 10 that detects the steering torque of the steering handle 1, and a motor 20 that assists the steering force of the steering handle 1 is coupled to the column shaft 2 via the reduction gear 3. ing. A steering angle sensor 15 for detecting the steering angle of the steering handle 1 is attached to the reduction gear 3. Further, the motor 20 is equipped with a motor angle detection circuit 42 such as a resolver for detecting the rotation angle of the motor (see FIG. 2). Electric power is supplied from the battery 14 via the ignition key 11 and the relay 13 to the control unit 30 which is a steering control drive device that controls the electric power steering device. Further, the control unit 30, by the motor angle detection circuit and the detected steering angle signal theta _H by the vehicle speed signal V and the steering angle sensor 15 detected by the steering torque signal T and the vehicle speed sensor 12 detected by the torque sensor 10 detected motor angle signal theta _M is input, performs the calculation of the steering assist command value I of an assist command based on these signals, the current (assist supplied to the motor 20 based on the calculated control steering assist command value I Assist control is performed by controlling (current).

  The control unit 30 mainly includes a CPU, a ROM, a RAM, an interface circuit, and the like. Inside, the program stored in ROM etc. is read and the said assist control is implemented.

As shown in FIG. 2, the control unit 30 includes a steering assist command value calculator 31, a phase compensator 32, a maximum current limiter 33, a motor drive circuit 34, a SATFeedBack compensator 35, a differentiator 36, and a convergence controller 37. Inertia compensator 38, steering wheel return control unit 40, steering angle signal control unit 41, motor angular velocity calculation unit 43, motor angular acceleration calculation unit 39, relative steering angle calculation unit 44, subtractor 45, adders 46a, 46b, 46c. Further, signals inputted from the outside such as the steering torque signal T, the vehicle speed signal V, the steering angle signal θ _H, and the motor angle signal θ _M inputted to the control unit 30 can be calculated by the control unit 30. Thus, for example, an analog signal is converted into a digital signal by an A / D converter (not shown). The signal such as the speed signal V may be input to the control unit 30 via a digital communication line such as CAN mounted on the vehicle. Further, these signals are amplified by an amplifier (not shown), and subjected to a filtering process as appropriate by a low-pass filter (not shown).

  A steering torque signal T generated as a result of the steering operator operating the steering handle 1 is detected by the torque sensor 10 and input to the steering assist command value calculation unit 31 after being appropriately subjected to amplification processing and filtering treatment.

  The steering assist command value calculation unit 31 outputs a control steering assist command value I to be supplied to the motor based on the input steering torque signal T. Further, the control steering assist command value I is determined by referring to an assist map prepared in advance, for example, so as to increase as the steering torque signal T shows a larger value. Considering this, the steering assist command value calculation unit 31 limits the output of the control steering assist command value I to an appropriate value when the steering torque signal T indicates a value greater than or equal to a predetermined value. Thereby, the steering force of the steering input by the steering person is reduced, and the vehicle behavior is stabilized.

The control steering assist command value I output from the steering assist command value calculator 31 is input to the phase compensator 32. The phase compensator 32 performs phase compensation on the control steering assist command value I, and outputs a control steering assist command value I _P which phase compensation is performed. As a result, the phase compensator 32 improves the transient characteristics or stabilizes the control system.

  On the other hand, the steering torque signal T is input to the SATFeedBack compensator 35 and the differentiator 36.

  The SATFeedBack compensator 35 receives the steering torque signal T, corrects the control steering assist command value I in a direction that assists the operation of the steering handle 1, and improves the return of the steering handle 1 after steering. Further, the differentiator 36 takes in the steering torque signal T, corrects the control steering assist command value I according to the fluctuation of the steering torque signal T, and suppresses fluctuation of the auxiliary torque by the motor 20.

Convergence compensating unit 37 inputs the motor angular velocity omega _M which is calculated output in motor angular velocity calculation unit 43, in order to improve the convergence of the vehicle, the control steering assist in a direction that prevents the rotation of the steering wheel 1 The command value I is corrected to brake the swinging motion of the steering handle 1, and the behavior of the steering handle 1 after steering is stabilized.

The inertia compensator 38 receives the motor angular acceleration α _M calculated and output by the motor angular acceleration calculation unit 39 as an input, and drives such as the steering handle 1, the pinion rack mechanism 5, the motor 20, the reduction gear 3, and the like. The control steering assist command value I is corrected in accordance with the change in the inertial system to suppress the change in the assist torque. Thus, the inertia of the drive system is prevented from being transmitted to the steering person, and the steering feeling is improved.

  Here, the subtracter 45 subtracts the output of the differentiator 36 from the output of the SATFeedBack compensator 35. Further, the output of the subtracter 45 is added to the output of the convergence controller 37 and the output of the inertia compensator 38 by the adders 46a and 46b, and is input to the adder 46c.

Further, the in motor angular velocity calculation unit 43 fetches the motor angle signal theta _M for example from a motor angle detection circuit 42 which is configured by an resolvers, the motor angle signal theta _M, for example, by performing such differential treatment, wherein the motor angular velocity to calculate the signal ω _M. The motor angular velocity signal omega _M each steering wheel return control unit 40, is input to the motor angular acceleration calculation unit 39 and the convergence controller 37.

In the steering wheel return control unit 40, the motor angular speed signal ω _M , the vehicle speed signal V detected by the vehicle speed sensor, and the signal S that is the output of the steering angle signal control unit 41 described later are input, and the more natural. In order to give a steering feeling, the control steering assist command value I is corrected according to the steering angle of the steering handle 1 with respect to the straight traveling state of the vehicle. More specifically, the handle return control unit 40 mainly controls the output in accordance with the signal S. When it is determined that the signal S is large, the handle return control unit 40 performs the handle return control with a large auxiliary torque. When it is determined that the signal S is small, the steering wheel return control is performed with a small auxiliary torque. The output of the steering wheel return control unit 40, wherein the motor angular velocity signal omega _M is adjusted based on the vehicle speed signal V, for example, when the vehicle speed V is high, the signal S is assist torque at a constant small Thus, the control steering assist command value I is corrected. This realizes a comfortable steering feeling for the steering person.

As described above, in the motor angular velocity calculation unit 43, the motor angle signal theta _M is input, for example, by performing such differentiation process, calculates the motor angular velocity signal omega _M, the convergence control and the steering wheel return control unit 40 And output to the motor 37 and the motor angular acceleration calculation unit 39. Further, the motor angular acceleration calculation unit 39 receives the motor angular velocity signal ω _{M and} performs, for example, differentiation processing to calculate the motor angular acceleration α _M and outputs it to the inertia compensator 38. With these feedback configurations, feedback control is realized.

The relative steering angle calculating unit 44, the motor angle signal captures theta _M, relative steering angle multiplied by the reduction ratio of the reduction gear 3, which is attached to the motor 20 to handle equivalent to the steering angle signal theta _H The signal θ _M ′ is calculated and the result is output to the steering angle signal control unit 41.

The steering angle signal control unit 41 performs calculation processing based on the steering angle signal θ _H and the relative steering angle signal θ _M ′, and outputs a signal S that is the calculation result to the steering wheel return control unit.

Adders 46c receives the output of the adder 46b, and addition processing and outputs said control steering assist command value I _P of the handle return control unit 40, inputs the resulting output to the maximum current limit 33 is doing. The maximum current limiting unit 33 limits the maximum current input to the motor 20 to an appropriate value in order to prevent damage due to overcurrent of the control unit 30 and the motor.
As described above, the current command value E supplied to the motor is input to the motor drive circuit 34.

  In the present embodiment, a brushless motor is used as the motor 20. A plurality of N poles and S poles are alternately arranged and fixed over the circumference of the rotor of the brushless motor, and a stator coil is arranged over the circumferential direction so as to enclose the rotor. . In addition, a Hall element is used as a magnetic pole position detection element in the brushless motor, and the Hall element detects the phase of the magnetic pole of the rotor, and a current flowing through each stator coil in accordance with the detected phase. A rotational torque can be obtained by selectively switching.

  The motor drive circuit 34 supplies and switches the current, and performs an operation such that the current control value E is achieved. Thereby, the assist control for adding the assist torque by the motor 20 to the steering system is realized.

  Further, the steering angle signal control unit 41 will be described in detail with reference to FIG. FIG. 3 is a block diagram showing the steering angle signal control device 41. As shown in FIG.

  The steering angle signal control device 41 according to this embodiment includes a steering angle sensor abnormality detection unit (abnormality detection means) 50, a steering angle estimation signal output determination unit 51, a steering angle midpoint output unit 52, and an adder 55. , Subtracters 54a and 54b, and multipliers 53a and 53b.

The steering angle sensor abnormality detecting unit 50 captures the steering angle signal theta _H, from the steering angle signal theta _H, for sensing the occurrence of abnormality such as a failure or disconnection of the steering angle sensor. Based on the detection result, the value Flg1 is output. That is, when the steering angle sensor abnormality detection unit 50 determines that the value is normal, the value Flg1 is set to “1”, and when the value is determined to be abnormal, the value Flg1 is set to “0”. Is output.

  The steering angle estimation signal output determination unit 51 receives the value Flg1, and when the value Flg1 is “1”, the value Flg2 is “0”, and when the value Flg1 is “0”, the value Flg2 is “1”. Is set and the value Flg2 is output. The steering angle sensor abnormality detection unit 50 is used until the vehicle stops or until the steering sensor abnormality detection unit 50 determines that the steering angle sensor 15 has returned to the normal state from the abnormality occurrence, that is, the control unit. As long as the power is kept on at 30, the occurrence of the abnormality is detected at a predetermined cycle.

On the other hand, the subtractor 54a the steering angle signal theta _H and the relative steering angle signal theta _{M 'is} inputted, the relative steering angle signal theta _M' is the steering angle midpoint by subtracting the steering angle signal theta _H from The signal θ _C is calculated, and the steering angle midpoint signal θ _C is output to the steering angle midpoint output unit 52.

The The steering angle midpoint output unit 52, the value Flg1 an output of the steering angle midpoint signal theta _C and the steering angle sensor abnormality detecting unit 50 is inputted. The steering angle midpoint output unit 52 is configured to determine the value to be output to the subtractor 54b on the basis of these signals, and a signal storage unit 52a for storing the steering angle midpoint signal theta _C inputted sequentially . Is the signal storage unit 52a stores the steering angle midpoint signal theta _C at a predetermined period. With this configuration, when the value Flg1 is set to “1”, the steering angle midpoint output unit 52 outputs the steering angle midpoint signal θ _{C that} is currently captured and stored from the signal storage device 52a. is, in the case of the value Flg1 is "0", one cycle before the steering angle midpoint signal theta _C, the steering angle midpoint signal theta _C immediately before the words abnormality is output. This output result is input to the subtractor 54b, and the subtractor 54b subtracts the relative steering angle signal θ _M ′ from the output of the steering angle midpoint output unit 52, whereby the steering angle estimation signal θ _{E, 1} is output.

The steering angle estimation signal θ _{E, 1} is input to the multiplier 53b, multiplied by the value Flg2, and the result is input to the adder 55. On the other hand, the multiplier 53 a multiplies the steering angle signal θ _H detected by the steering angle sensor 15 and the value Flg 1 and inputs the result to the adder 55.

  The adder 55 adds the output result of the multiplier 53 a and the output result of the multiplier 53 b to calculate the signal S, and outputs the signal S to the handle return control unit 40.

  Next, the operation flow of the steering angle signal control unit 41 in the above-described configuration will be described with reference to the flowchart of FIG.

The steering angle sensor abnormality detection unit 50 determines whether an abnormality such as a failure or disconnection of the steering angle sensor has occurred (that is, S100). When detecting occurrence of abnormality, the steering angle signal theta _H invalidates the output so as not to output to the steering wheel return control unit 40 together (i.e. S110), the steering angle estimation signal theta _{E, 1} is output to the steering wheel return control unit 40 The output is validated as described above (ie, S111). Here, the steering angle midpoint output unit 52 obtains the steering angle midpoint signal theta _C for 1 cycle before the abnormality occurred when the signal storage unit 52a from the signal storage unit 52a outputs (S112). Next, a steering angle estimation signal θ _{E, 1} is calculated from the steering angle midpoint signal θ _C and the relative steering angle signal θ _M ′ (S113) and output to the steering wheel return control unit 40 (S101). As a result, when occurrence of an abnormality is detected, the steering angle estimation signal θ _{E, 1} calculated from the steering angle midpoint signal θ _C one cycle before the time when the abnormality has occurred is input to the steering wheel return control unit 40. .

Also, in the case of not detecting the abnormality, the steering angle signal theta _H to enable the output to be outputted to the steering wheel return control unit 40 together (i.e. S120), the steering angle estimation signal theta _{E, 1} handle return control The output is invalidated so as not to be output to the unit 40 (ie, S121). Here, the steering angle midpoint output unit 52 obtains from the steering angle midpoint signal theta _C signal storage unit 52a of the current output (S122). Then, the steering angle estimation signal θ _{E, 1} is calculated from the steering angle midpoint signal θ _C and the relative steering angle signal θ _M ′ (S123), but since the output is invalidated, the steering angle The estimated signal θ _{E, 1} is not output to the steering wheel return control unit 40, and the steering angle signal θ _H detected by the steering angle sensor is directly input to the steering wheel return control unit 40.

Therefore, according to the present embodiment, the control unit 30 uses the steering angle signal θ _H detected by the steering angle sensor 15 and the motor angle signal θ _M detected by the motor angle detection circuit 42 to control the steering angle midpoint signal θ. calculates a _C, and a signal storage unit 52a for storing the steering angle midpoint signal theta _C, when said steering angle sensor abnormality detecting section 50 detects the abnormality of the steering angle sensor 15, the signal storage Based on the steering angle midpoint signal θ _C immediately before the occurrence of the abnormality stored in the part 52 a and the motor angle signal θ _M , the motor 20 is controlled and continuously operated, so that the steering feeling changes rapidly. In addition, it is possible to realize safe and comfortable steering that can suppress steering feeling loss.

  In addition, according to the present embodiment, the control unit 30 continues until the vehicle 20 stops or until the steering sensor abnormality detection unit 50 determines that the steering angle sensor has returned to the normal state from the abnormality occurrence. Therefore, as long as the steering wheel is steered by the steering wheel 1, the steering feeling loss can be suppressed, and safer and more comfortable steering can be realized.

(Second Embodiment)
A modification of the first embodiment according to the present invention will be described with reference to FIGS. FIG. 5 is a block configuration diagram of the steering angle signal control unit according to the present embodiment, and FIG. 6 is a block configuration diagram of the steering angle midpoint average value calculation unit. In the present embodiment, the steering angle midpoint average value calculation unit is provided in the configuration of the first embodiment described above.

  In the present embodiment, as shown in FIG. 5, the steering angle signal control unit 41 ′ is provided with a steering angle midpoint average value calculation unit 60 including a signal storage unit 60a.

The steering angle midpoint average value signal storage unit 60a of the calculating unit 60 stores a steering angle midpoint signal theta _C which is sequentially input in a predetermined cycle. As shown in FIG. 6, the steering angle midpoint average value calculation unit 60 includes delay elements Z ⁻¹ , Z ⁻² ,..., Z ^{−n + 1} from one cycle before to N−1 cycles. is configured, in the signal storage unit a plurality of recorded in 60a steering angle midpoint signal theta _C, based on the value N (where the value N is a natural number), N-1 cycle before the steering angle midpoint signal theta _C To the steering angle midpoint signal θ _C at the time of occurrence of an abnormality, and summing these signals and multiplying by a value 1 / N to calculate the average steering angle midpoint signal θ _C ′, The angle midpoint signal θ _C ′ is output to the steering angle midpoint output unit 52 ′. The value N is a preset value and can be changed from the outside sequentially.

The steering angle midpoint output unit 52 ′ receives the average steering angle midpoint signal θ _C ′ and the value Flg1 that is the output of the steering angle sensor abnormality detection unit 50. The steering angle midpoint output unit 52 ′ determines a value to be output to the subtractor 54b based on these signals, and stores the average steering angle midpoint signal θ _C ′ that is sequentially input. a. The signal storage unit 52′a stores the average steering angle midpoint signal θ _C ′ at a predetermined period. With this configuration, in the steering angle midpoint output unit 52 ′, when the value Flg1 is set to “1”, the average steering angle midpoint signal currently captured and stored from the signal storage device 52′a. theta _{C 'is} outputted, when a value Flg1 is "0", the preceding cycle of the average steering angle midpoint signal theta _C', that is, the steering angle midpoint signal theta _{C 'immediately} before the occurrence of abnormality is output .
Other aspects are the same as in the first embodiment.

  Therefore, according to the present embodiment, the same operational effects as the first embodiment can be obtained, but in particular, since the steering angle midpoint is calculated from the average value of the plurality of steering angle midpoints, the steering accuracy is more accurate when an abnormality occurs. An angle estimation signal can be calculated and output to the steering wheel return control unit, and steering feeling loss can be further suppressed.

(Third embodiment)
Furthermore, another embodiment according to the present invention will be described with reference to FIG. FIG. 7 is a block diagram of the steering angle signal control unit according to the present embodiment.
Unlike the first embodiment, the electric power steering apparatus (not shown) according to the present embodiment is not provided with a steering angle sensor, and is a signal detected by a detection means other than the steering angle sensor, for example, a steering torque signal. A steering angle estimation signal is calculated from T, a relative steering angle signal θ _M ′, and a vehicle speed signal V, and the motor 20 is controlled to add auxiliary torque to the steering.

  As shown in FIG. 7, the steering angle signal control unit 141 in this configuration includes a sensor abnormality detection unit 150, a steering angle estimation signal calculation unit 151, and a steering angle estimation signal output determination unit 152. Since the overall block configuration diagram in the present embodiment is basically the same as that of the first embodiment shown in FIG. 2 except for the steering angle sensor, description of the overall block configuration is omitted.

The sensor abnormality detection unit 150 receives the steering torque signal T, the relative steering angle signal θ _M ′, and the vehicle speed signal V, and detects the occurrence of abnormality in these signals. Based on the detection result, the value Flg3 is output. That is, when the sensor abnormality detection unit 150 determines that the value is normal, the value Flg3 is set to “1”, while when the value is determined to be abnormal, the value Flg3 is set to “0” and the value Flg3 is set. This is output to the steering angle estimation signal output determination unit 152.

In addition, the steering angle estimation signal calculation unit 151 calculates the steering angle estimation signal θ _{E, 2} from the steering torque signal T, the relative steering angle signal θ _M ′, and the vehicle speed signal V, and the steering angle It outputs to the estimated signal output determination part 152.

The steering angle estimation signal output determination unit 152 receives the value Flg3 and the steering angle estimation signal θE _{, 2} . The steering angle estimation signal output determination unit 152 determines a signal S ′ to be output to the steering wheel return control unit 40 based on these signals, and stores the steering angle estimation signal θ _{E, 2} that is sequentially input. Part 150a. With this configuration, in the steering angle estimation signal output determination unit 152, when the value Flg3 is set to “1”, the steering angle estimation signal θE, which is currently captured and stored in the signal storage device 152a _{. 2} is set to the signal S ′, while the value Flg3 is “0”, the steering angle estimation signal θ _{E, 2} before one cycle, that is, the steering angle estimation signal θ _{E, 2} is set to the signal S '. As a result, the signal S ′ is input to the handle return control unit 40.

Therefore, according to the present embodiment, the control unit includes the signal storage unit 150a that records the steering angle estimation signal θ _{E, 2,} and the sensor abnormality detection unit 150 performs the steering torque signal T and the relative steering angle signal θ. _{When the} occurrence of an abnormality in the signal of _M ′ or the vehicle speed signal V is detected, the motor 20 is controlled based on the steering angle estimation signal θ _{E, 2} immediately before the occurrence of the abnormality stored in the signal recording unit 152a. Since the operation is continued, the steering feeling does not change abruptly, and safe and comfortable steering that can suppress the steering feeling loss can be realized.

  Further, according to the present embodiment, the control unit controls and operates the motor 20 until the vehicle stops or until it is determined that the steering sensor abnormality detection unit 50 has returned to the normal state from the abnormality occurrence. Therefore, as long as the steering wheel steers the steering wheel 1, the steering feeling loss can be suppressed, and safer and more comfortable steering can be realized.

(Fourth embodiment)
A fourth embodiment according to the present invention will be described with reference to FIG. FIG. 8 is a block diagram of the steering angle signal control unit according to the present embodiment. In the present embodiment, in the configuration of the third embodiment described above, a steering angle midpoint average value calculation unit 260 and a steering angle midpoint output unit 252 are provided. Note that the electric power steering apparatus (not shown) according to the present embodiment is configured not to include a rudder angle sensor, as in the third embodiment, and is a signal detected by a detection unit other than the rudder angle sensor, for example, A steering angle estimation signal is calculated from the steering torque signal T, relative steering angle signal θ _M ′, and vehicle speed signal V, and the motor 20 is controlled to add auxiliary torque to the steering.

  As shown in FIG. 8, the steering angle signal control unit 241 according to the present embodiment includes a steering angle estimation signal calculation unit 151, a sensor abnormality detection unit 250, a steering angle estimation signal output determination unit 251, and a steering angle midpoint. An average value calculation unit 260, a steering angle midpoint output unit 252, an adder 255, subtracters 254a and 254b, and multipliers 253a and 253b are provided.

The steering angle estimation signal calculation unit 151 calculates a steering angle estimation signal θ _{E, 2} from the steering torque signal T, the vehicle speed signal V, and the relative steering angle signal θ _M ′, and supplies the steering angle estimation signal θ _{E, 2} to the multiplier 253a and the subtractor 254a. Output.

  The sensor abnormality detection unit 250 takes in the steering torque signal T and the vehicle speed signal V, and detects the occurrence of abnormality from these signals. Based on this detection result, the value Flg4 is output. That is, when the sensor abnormality detection unit 250 determines that the value is normal, the value Flg4 is set to “1”, and when it is determined to be abnormal, the value Flg4 is set to “0” and the value Flg4 is set. Output.

  The steering angle estimation signal output determination unit 251 receives the value Flg4. When the value Flg4 is “1”, the value Flg5 is “0”, and when the value Flg4 is “0”, the value Flg5 is “1”. Is set and the value Flg5 is output.

On the other hand, the subtracter 254a the steering angle estimation signal theta _{E, 2} and the relative steering angle signal theta _{M 'is} inputted, the relative steering angle signal theta _M' in the from the steering angle estimation signal theta _{E, 2} subtraction processing Then, the steering angle midpoint estimation signals θ _{C and E} are calculated, and the steering angle midpoint estimation signals θC _{and E} are output to the steering angle midpoint average value calculation unit 260.

The steering angle midpoint average value calculation unit 260 includes a signal storage unit 260a. The signal storage unit 260a stores steering angle midpoint estimation signals θ _{C and E} that are sequentially input at a predetermined cycle. The steering angle midpoint average value calculation unit 260 is the same as in the second embodiment (see FIG. 6), and the delay elements Z ⁻¹ , Z ⁻² ,. Z− ^{n + 1} , and in the plurality of steering angle midpoint estimation signals θ _{C and E} recorded in the signal storage unit 260a, based on the value N (where the value N is a natural number), N−1 periods Calculate from the previous steering angle midpoint estimation signal θ _{C, E} to the steering angle midpoint signal θ _{C, E} at the time of occurrence of an abnormality, add these signals, multiply by the value 1 / N, and calculate the average steering angle The midpoint estimation signal θ _{C, E} ′ is calculated, and the average steering angle midpoint estimation signal θ _{C, E} ′ is output to the steering angle midpoint output unit 252.

The steering angle midpoint output unit 252 receives the average steering angle midpoint estimation signal θ _{C, E} ′ and the value Flg4 that is the output of the sensor abnormality detection unit 250. The rudder angle midpoint output unit 252 determines a value to be output to the subtractor 254b based on these signals, and stores the average rudder angle midpoint estimation signals θ _{C, E} ′ that are sequentially input. 252a. The signal storage unit 252a stores the average steering angle midpoint estimation signal θ _{C, E} ′ at a predetermined cycle. With this configuration, when the value Flg4 is set to “1” in the steering angle midpoint output unit 252, the average steering angle midpoint estimation signal θ _C currently taken in and stored from the signal storage device 252 a. _{, E 'is} outputted, when a value Flg4 is "0", the preceding cycle of the average steering angle midpoint estimation signal theta _{C, E',} namely the average steering angle midpoint estimation signal immediately before the abnormality occurs theta _{C , E} ′ are output. This output result is input to the subtractor 254b, and the subtractor 254b subtracts the relative rudder angle signal θ _M ′ from the output of the rudder angle midpoint output unit 252, thereby obtaining the rudder angle estimation signal θ _{E. , 3} is output.

The steering angle estimation signal θ _{E, 3} is input to the multiplier 253b, multiplied by the value Flg5, and the result is input to the adder 255. On the other hand, the multiplier 253 a multiplies the steering angle estimation signal θ _{E, 2} detected by the steering angle estimation signal calculation unit 151 and the value Flg 4 and inputs the result to the adder 255.

  The adder 255 adds the output result of the multiplier 253 a and the output result of the multiplier 253 b to calculate the signal S ″, and outputs the signal S ″ to the handle return control unit 40.

With this configuration, when the sensor abnormality detection unit 250 determines that the steering is normal, the steering angle estimation signal θ _{E, 2} calculated by the steering angle estimation signal calculation unit 151 is output to the steering wheel return control unit 40. When the determination is made, an average steering angle midpoint estimation signal θ _{C, E} ′ is calculated from the N steering angle midpoint estimation signals θ _{C, E} stored immediately before the occurrence of an abnormality _, and the average steering angle midway The steering angle estimation signal θ _{E, 3} is calculated from the point estimation signal θ _{C, E} ′ and the relative steering angle signal θ _M ′, and is output to the steering wheel return control unit.

  Therefore, according to the present embodiment, the same effect as the third embodiment is obtained, but in particular, since the signal S ″ is calculated by an average value of a plurality of steering angle midpoint estimated values, An accurate steering angle estimation signal can be calculated and output to the steering wheel return control unit, and the steering feeling loss can be further suppressed, and the stability of the electric power steering control device can be maintained.

The description of the specific embodiments is finished above, but the aspect of the present invention is not limited to these embodiments, and modifications, improvements, and the like can be made as appropriate. For example, in the present embodiment, most of the processing is performed by software, but a part or all of the processing may be realized by hardware such as FPGA (Field Programmable Gate Array). In addition, the steering torque signal T, the relative steering angle signal θ _M ′, and the vehicle speed signal V have been exemplified and described as signals for estimating the steering angle, but the present invention is not limited thereto, and wheel speeds may be used.

  Furthermore, in the present embodiment, the steering wheel return control unit has been described as an example. However, the present invention is not limited to this, and the present invention can be applied to various control units and compensation units that take in a steering angle signal and perform processing.

  The present invention is applicable to all electric power steering devices regardless of the type of electric power steering device (column type, pinion type, rack type) and the type of motor (with brush, brushless, etc.).

1 is a schematic diagram of an electric power steering apparatus according to a first embodiment of the present invention. It is a block block diagram of the control unit of the electric power steering device according to the first embodiment. It is a block block diagram of the steering angle signal control part which concerns on 1st Embodiment. It is a flowchart which shows operation | movement of the steering angle signal control part in 1st Embodiment. It is a block block diagram of the steering angle signal control part which concerns on 2nd Embodiment. It is a block block diagram of the steering angle middle point average value calculation part in 2nd Embodiment. It is a block block diagram of the steering angle signal control part which concerns on 3rd Embodiment. It is a block block diagram of the steering angle signal control part which concerns on 4th Embodiment.

Explanation of symbols

10 Torque sensor 12 Vehicle speed sensor 15 Steering angle sensor (steering angle detection means)
20 motor 30 control unit (steering control drive circuit)
40 Steering wheel return control units 41, 41 ', 141, 241 Steering angle signal control unit 42 Motor angle detection circuit (motor angle detection means)
50 Rudder angle sensor abnormality detection unit (abnormality detection means)
51, 152, 251 Steering angle estimation signal output determination unit 52, 52 ', 252 Steering angle midpoint output unit 52a, 52a', 60a, 152a, 260a, 252a Signal storage unit (signal storage means)
60,260 Steering angle midpoint average value calculation unit (signal calculation processing means)
150, 250 Sensor abnormality detection unit 151 Steering angle estimation signal calculation unit (steering angle estimation means)

Claims (4)

A steering angle detection means for detecting the steering angle of the steering, a steering control drive device for controlling the motor to apply an auxiliary torque to the steering, an abnormality detection means for determining an abnormality of the steering angle detection means, In an electric power steering apparatus comprising a motor angle detection means for detecting a rotation angle,
The steering control drive device calculates steering angle information related to the steering angle signal detected by the steering angle detection means,
Comprising signal storage means for storing the rudder angle information,
When the abnormality detection means detects the abnormality occurrence of the rudder angle detection means,
And the steering angle information of the abnormality occurrence immediately before recorded in the signal SL 憶 means, on the basis of the motor angle signal detected by the motor angle detecting means,
An electric power steering apparatus characterized in that the motor is continuously operated while being controlled. The electric power steering apparatus according to claim 1, wherein
The electric power steering apparatus according to claim 1, wherein the steering angle information is a steering angle midpoint signal calculated from the steering angle signal and the motor angle signal. In the electric power steering device according to claim 1 or 2,
The steering control drive device includes signal calculation processing means for calculating an average value of the steering information stored in the signal storage means for a predetermined time,
When the abnormality detection means detects the abnormality occurrence of the rudder angle detection means,
Based on the calculation result of the signal arithmetic processing means,
An electric power steering apparatus characterized in that the motor is continuously operated while being controlled. In the electric power steering device according to any one of claims 1 to 3 ,
The steering control drive device until the vehicle stops or until the abnormality detection means determines that the signal has returned to the normal state from the occurrence of the abnormality.
An electric power steering apparatus characterized in that the motor is continuously operated while being controlled.

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