JP6288155B2 - Vehicle vibration control device - Google Patents

Description

  The present invention relates to a vibration control device that controls vibration of a vehicle.

  Various control techniques for controlling the electric power steering have been developed (see Patent Documents 1 and 2). Patent Document 1 discloses a technique for reducing a calculation load when calculating an assist torque for assisting a driver's steering. Patent Document 2 discloses a control technique that not only outputs an appropriate assist torque but also exhibits a function of reducing vibration transmitted to the steering wheel.

JP-A-2006-580 JP 2016-22927 A

  Although the control technique of Patent Document 2 works to reduce vibration, it does not consider the natural frequency of the components of the steering mechanism that form the transmission path of the steering force from the steering wheel to the wheels. When the frequency of the angular change of the motor matches or approaches the natural frequency of a plurality of parts constituting the steering mechanism, these parts will resonate with respect to the angular motion of the motor. Therefore, the vehicle designer has avoided the simultaneous resonance of the plurality of parts by making the natural frequencies of the plurality of parts constituting the steering mechanism different from each other.

  If a control system that takes into account the natural frequencies of the components of the steering mechanism is constructed under the above-described prior art, a very complicated calculation process is required. Alternatively, avoiding resonance of one component may cause resonance of another component.

  An object of the present invention is to provide a control technique that reduces the risk of resonance of components of a steering mechanism.

  A vehicle vibration control device according to one aspect of the present invention includes a steering mechanism that performs a steering operation that changes the direction of a pair of wheels, a motor that provides the steering mechanism with assist torque that assists the steering operation, and rotation of the motor. An angle signal generation unit that generates an angle signal that represents an angle, and a controller that controls the motor according to the angle signal. The steering mechanism includes a column shaft extending from a steering wheel, a pinion rack mechanism having a rack extending between the pair of wheels and a pinion meshing with the rack, and an intermediate shaft connecting the column shaft and the pinion. And including. The frequency range between the largest natural frequency and the smallest natural frequency among the column shaft, the pinion rack mechanism, and the intermediate shaft is less than 2 hz. The controller includes a first torque determining unit that determines a first torque from a steering torque generated in the steering mechanism under the rotation of the steering wheel, a correcting unit that determines a correction value for the first torque, and the correction value. And a second torque determining unit that corrects the first torque and determines the assist torque. The angle signal includes a plurality of signal components that vibrate at a frequency within the frequency range. The correction unit multiplies the plurality of signal components with a specific high gain, processes the angle signal, and determines the correction value.

  According to the above configuration, since the frequency range between the largest natural frequency and the smallest natural frequency among the column shaft, the pinion rack mechanism, and the intermediate shaft is less than 2 hz, the column shaft, the pinion rack mechanism And the controller can control the motor so that resonance of the intermediate shaft is avoided at once. The correction unit multiplies a plurality of signal components that vibrate at a frequency within the frequency range, processes the angle signal, and determines a correction value. Therefore, the correction value is used to correct the first torque. The 2-torque determination unit can determine the assist torque so that resonance of the column shaft, the pinion rack mechanism, and the intermediate shaft is avoided at a time.

  In the above configuration, the correction unit may process the angle signal so that one phase of the plurality of signal components advances by 90 ° to determine the correction value.

  According to the above configuration, the correction unit processes the angle signal so that one phase of the plurality of signal components advances by 90 ° and determines the correction value, so the controller vibrates at a frequency within the frequency range. A large viscous damping can be caused specifically in the vibration component.

  With respect to the above configuration, the correction unit multiplies the plurality of signal components by the gain, and processes and corrects the angle signal so that one phase of the plurality of signal components advances by 90 °. A high-pass filter that generates an angle signal, and a correction value calculation unit that calculates a correction amount for the first torque from the corrected angle signal as the correction value may be included. The second torque determination unit may include an adder that adds the correction amount calculated by the correction value calculation unit to the first torque and determines the assist torque.

  According to the above configuration, the angle signal is processed such that a plurality of signal components that vibrate at a frequency within the frequency range are multiplied by a high gain, and one phase of the plurality of signal components advances by 90 °. Since the corrected angle signal is generated, the controller can generate a large viscous damping specifically for the vibration component that vibrates at a frequency within the frequency range. Since the correction value calculation unit calculates the correction amount for the first torque from the corrected angle signal as the correction value, the correction value calculation unit collectively suppresses resonance of the column shaft, the pinion rack mechanism, and the intermediate shaft. Thus, the correction amount can be determined. The adder adds the correction amount calculated by the correction value calculation unit to the first torque to determine the assist torque, so that the motor can avoid the resonance of the column shaft, the pinion rack mechanism, and the intermediate shaft all at once. In addition, the assist torque can be output to the steering mechanism.

  With regard to the above configuration, the natural angular frequency of the transfer function of the high-pass filter may be set in the frequency range.

  According to the above configuration, since the natural angular frequency of the transfer function of the high-pass filter is set in the frequency range, the high-pass filter can specifically multiply a plurality of signal components in the frequency range by a high gain. .

  With regard to the above configuration, the damping constant of the transfer function may be set so that a peak appears in the frequency range.

  According to the above configuration, since the attenuation constant of the transfer function is set so that a peak appears in the frequency range, the high-pass filter may multiply a plurality of signal components in the frequency range specifically with a high gain. it can.

  With regard to the above configuration, a vehicle vibration control device includes: a frame member; a pair of tie rods that respectively connect the rack and the pair of wheels; and a pair of suspension devices that suspend the pair of tie rods from the frame member. Further, it may be provided. Each of the frame member, the pair of tie rods, and the pair of suspension devices may have a natural frequency within the frequency range.

  According to the above configuration, each of the frame member, the pair of tie rods, and the pair of suspension devices has a natural frequency within the frequency range, so that the vibration control device includes the frame member, the pair of tie rods, and the pair of pairs The risk of suspension resonance can also be reduced.

  Regarding the above configuration, the frequency range may be 1 hz or less.

  According to the above configuration, since the frequency range is 1 hz or less, the vibration control device can effectively reduce the risk of resonance.

  The vibration control device described above can reduce the risk of resonance of the components of the steering mechanism.

It is a notional block diagram of a control device illustrated as a vibration control device of a 1st embodiment. It is a notional block diagram of a control device illustrated as a vibration control device of a 2nd embodiment. FIG. 3 is a Bode diagram showing an exemplary frequency characteristic of a high-pass filter of the control device shown in FIG. 2. It is a conceptual diagram of the control apparatus illustrated as a vibration control apparatus of 3rd Embodiment. It is a conceptual diagram of the control apparatus illustrated as a vibration control apparatus of 4th Embodiment. It is a conceptual block diagram of the control apparatus illustrated as a vibration control apparatus of 5th Embodiment. 7 is a graph conceptually showing exemplary data stored in a storage unit of the control device shown in FIG. 6. It is a conceptual block diagram of the control apparatus illustrated as a vibration control apparatus of 6th Embodiment. FIG. 9 is a graph conceptually showing gain data stored in an adjustment unit of the control device shown in FIG. 8.

<First Embodiment>
A steering mechanism that transmits a steering force from a steering wheel to a wheel generally includes a column shaft, an intermediate shaft, and a pinion rack mechanism. Conventionally, the column shaft, the intermediate shaft and the pinion rack mechanism are designed so that the natural frequencies of the column shaft, the intermediate shaft and the pinion rack mechanism are different from each other by 2 hz or more. As a result, simultaneous resonance of two or all of the column shaft, the intermediate shaft and the pinion rack mechanism has been avoided. On the other hand, the conventional control technique had to suppress the resonance of each of the column shaft, the intermediate shaft, and the pinion rack mechanism. As a result, conventional control techniques require very complex calculations. Alternatively, the conventional control technique may suppress the resonance of one of the column shaft, the intermediate shaft, and the pinion rack mechanism, while causing another resonance of the column shaft, the intermediate shaft, and the pinion rack mechanism. It was. The inventors of the present invention have developed a control technology that sets the natural frequencies of the column shaft, the intermediate shaft, and the pinion rack mechanism within a narrow range, and collectively suppresses these resonances. In the first embodiment, an exemplary control technique is described.

  FIG. 1 is a conceptual block diagram of a control device 100 exemplified as the vibration control device of the first embodiment. The control apparatus 100 is demonstrated with reference to FIG.

  The control device 100 includes a steering mechanism 200, a motor 300, an angle detection unit 400, and a controller 500. The steering mechanism 200 transmits the steering force applied to the steering wheel STW to the pair of wheels WHL. As a result, the steering mechanism 200 can change the direction of the pair of wheels WHL (that is, steering operation). The motor 300 gives assist torque to the steering mechanism 200 under the control of the controller 500. As a result, the driver can rotate the steering wheel STW with a small force.

  The angle detector 400 detects the rotation angle of the motor 300 (that is, the rotation angle of the output shaft (not shown) of the motor 300). The angle detection unit 400 generates an angle signal representing the detected rotation angle. The angle signal is transmitted from the angle detection unit 400 to the controller 500. The angle detection unit 400 may be an encoder or another detection element that detects the rotation angle of the motor 300. The principle of the present embodiment is not limited to a specific device used as the angle detection unit 400. In the present embodiment, the angle signal generation unit is exemplified by the angle detection unit 400.

  When the driver rotates the steering wheel STW, steering torque is generated in the steering mechanism 200. The steering torque may be detected by a general torque sensor (not shown) or other appropriate detection element (not shown: for example, a strain gauge). The controller 500 receives a torque signal representing the detected steering torque in addition to the angle signal. The controller 500 controls the motor 300 according to the angle signal and the torque signal.

  Steering mechanism 200 includes a column shaft 210, an intermediate shaft 220, and a pinion rack mechanism 230. The motor 300 is connected to one of the column shaft 210, the intermediate shaft 220, and the pinion rack mechanism 230.

  The pinion rack mechanism 230 includes a rack 231 and a pinion 232. The column shaft 210 extends from the steering wheel STW. The rack 231 extends between the pair of wheels WHL. The pinion 232 meshes with the rack 231. The intermediate shaft 220 is connected to the pinion 232 and the column shaft 210 extending from the steering wheel STW.

  The rotational force (that is, steering force) applied by the driver to the steering wheel STW and / or the assist torque transmitted from the motor 300 is transmitted to the pinion 232 through the column shaft 210 and the intermediate shaft 220. As a result, the pinion 232 rotates. The rack 231 moves linearly between the pair of wheels WHL according to the rotation of the pinion 232. The pair of wheels WHL change directions according to the linear movement of the rack 231.

  FIG. 1 represents the natural frequency of the column shaft 210 by the symbol “Fcls”. FIG. 1 represents the natural frequency of the intermediate shaft 220 by the symbol “Fims”. FIG. 1 represents the natural frequency of the pinion rack mechanism 230 by the symbol “Fprm”. The following inequality represents the relationship between these natural frequencies.

  The controller 500 includes a first torque determination unit 510, a second torque determination unit 520, and a correction unit 530. The first torque determination unit 510 receives the torque signal described above. First torque determination unit 510 determines a first torque corresponding to the steering torque represented by the torque signal. Information about the first torque is output from the first torque determination unit 510 to the second torque determination unit 520. The first torque may be determined based on various known calculation techniques such as an assist map. The principle of the present embodiment is not limited to a specific calculation technique for determining the first torque.

  The first torque determination unit 510 includes a memory that stores data representing the relationship between the steering torque and the first torque (for example, a lookup table), and a CPU (Central) that executes a program designed to read data from the memory. Processing Unit). The CPU may further execute a program designed to generate a signal from the read data.

  The correction unit 530 receives the angle signal described above. The correction unit 530 performs frequency analysis on the angle signal. The frequency analysis may be a fast Fourier transform (FFT). Alternatively, other arithmetic techniques (eg, FRA: Frequency Response Analyzer) may be used for frequency analysis. The principle of the present embodiment is not limited to a specific frequency analysis technique performed by the correction unit 530.

  As a result of the frequency analysis, the correction unit 530 can obtain a plurality of signal components that differ in frequency from the angle signal. The correcting unit 530 can find a plurality of signal components having a frequency within the above inequality range from the plurality of signal components obtained from the frequency analysis. The correction unit 530 multiplies the plurality of found signal components with a specific high gain to process the angle signal. That is, the correction unit 530 multiplies a plurality of signal components having a frequency within the above inequality range by a gain higher than the plurality of signal components having a frequency outside the above inequality range. The correction unit 530 determines a correction value using the processed angle signal. Information regarding the correction value is transmitted from the correction unit 530 to the second torque determination unit 520.

  The correction unit 530 may include a frequency analyzer or may be a CPU that executes a program designed for frequency analysis. The CPU may further execute a program designed to multiply the specific signal component obtained from the frequency analysis by a specific high gain and correct the angle signal.

  The second torque determination unit 520 corrects the first torque using the correction value and determines the assist torque. The motor 300 outputs the determined assist torque to the steering mechanism 200 under the control of the controller 500. The second torque determination unit 520 may be an adder that adds the correction value to the first torque, or a CPU that executes a program designed for addition processing that adds the correction value to the first torque. Also good.

  The angle signal generally includes signals of various frequency ranges. The correction unit 530 gives a specifically high correction value to a plurality of signal components having frequencies within the above inequality range. As a result, the second torque determination unit 520 can determine the assist torque so that the risk of resonance of the column shaft 210, the intermediate shaft 220, and the pinion rack mechanism 230 is collectively reduced.

Second Embodiment
The correction process described in connection with the first embodiment can be executed using a second-order high-pass filter. In the second embodiment, an exemplary vibration control device that performs correction processing using a high-pass filter will be described.

  FIG. 2 is a conceptual block diagram of a control device 100A exemplified as the vibration control device of the second embodiment. The description of the first embodiment is applied to elements having the same reference numerals as those of the first embodiment. The control device 100A will be described with reference to FIGS.

  Similar to the first embodiment, the control device 100A includes a steering mechanism 200, a motor 300, and an angle detection unit 400. The description of the first embodiment is incorporated in these elements.

  The control device 100A further includes a controller 500A. As in the first embodiment, the controller 500A includes a first torque determination unit 510. The description of the first embodiment is incorporated in the first torque determination unit 510.

  The controller 500A further includes a correction unit 530A and an adder 520A. The correction unit 530A includes a high-pass filter 531 and a correction value calculation unit 532. The angle signal is output from the angle detection unit 400 to the high pass filter 531. The high pass filter 531 corrects the angle signal. The angle signal corrected by the high pass filter 531 is output to the correction value calculation unit 532.

  The correction value calculation unit 532 converts the corrected angle signal into a correction signal representing torque. The transfer function of the correction value calculation unit 532 depends on the input / output characteristics of the motor 300. Various known calculation techniques can be applied to the conversion process from the corrected angle signal to the correction signal representing the torque. Therefore, the principle of the present embodiment is not limited to the specific calculation processing of the correction value calculation unit 532.

  The adder 520A corresponds to the second torque determination unit 520 described with reference to FIG. Therefore, the description regarding the second torque determination unit 520 may be incorporated into the adder 520A.

  The adder 520 </ b> A receives the correction signal from the correction value calculation unit 532. Information representing the first torque is output from the first torque determination unit 510 to the adder 520A. The correction signal received from the correction value calculation unit 532 by the adder 520A represents a correction amount for the first torque. The adder 520A adds the correction amount represented by the correction signal to the first torque, and determines the assist torque. The motor 300 outputs the assist torque determined by the adder 520A to the steering mechanism 200.

  FIG. 3 is a Bode diagram showing an exemplary frequency characteristic of the high-pass filter 531. The frequency characteristics of the high-pass filter 531 will be described with reference to FIGS.

  The following formula represents the transfer function G (s) of the high-pass filter 531.

  As shown in FIG. 3, the designer who designs the control device 100 </ b> A determines the damping constant of the high-pass filter 531 so that a peak appears in the gain diagram at a predetermined natural angular frequency (for example, 10 hz). In the present embodiment, the natural angular frequency is set to “10 hz”. The high pass filter 531 outputs a gain having a value of “10” with respect to a signal component of “10 hz” in the angle signal.

  The designer may set the range of “± 1 hz” around the natural angular frequency as a range in which the natural frequencies of the column shaft 210, the intermediate shaft 220, and the pinion rack mechanism 230 are dispersed. The designer may design the column shaft 210, the intermediate shaft 220, and the pinion rack mechanism 230 so that the natural frequency falls within a set range.

  Alternatively, the designer may use the column shaft 210, the intermediate shaft 220, and the pinion rack mechanism 230 so that the difference between the maximum and minimum natural frequencies is less than “2 hz”. Each of the intermediate shaft 220 and the pinion rack mechanism 230 may be designed. The designer then enters the high-pass filter so that the natural angular frequency of the transfer function of the high-pass filter 531 falls between the maximum value and the minimum value of the natural frequency of the intermediate shaft 220 and the pinion rack mechanism 230. 531 may be designed.

  The high-pass filter 531 applies fast Fourier transform to the angle signal to obtain a plurality of signal components that differ in frequency. As shown in FIG. 3, the gain assigned to the frequency band from “9 hz” to “11 hz” is different from the other frequency bands (that is, the frequency band of “1 hz” to “9 hz” and “11 hz”). Greater than the gain assigned to the higher frequency band. The high pass filter 531 finds a plurality of signal components distributed in a frequency band from “9 hz” to “11 hz” from the plurality of signal components obtained by the fast Fourier transform. The high-pass filter 531 multiplies the power spectrum of the plurality of found signal components specifically by a high gain. The high-pass filter 531 multiplies the power spectrum of other signal components (that is, signal components that do not belong to the frequency band from “9 hz” to “11 hz”) by a relatively low gain. As a result, the angle signal is corrected so that the signal component belonging to the frequency band in which the natural frequencies of the column shaft 210, the intermediate shaft 220, and the pinion rack mechanism 230 are distributed is emphasized.

  As shown in FIG. 3, the high-pass filter 531 advances the phase of the signal component having a frequency of “10 hz” by 90 °. The high-pass filter 531 has other signal components distributed in the frequency band from “9 hz” to “11 hz” (that is, signal components of “9 hz” to “10 hz” and signals greater than “10 hz” and “11 hz” or less). The phase of the component is advanced by about 90 °. As a result, the high-pass filter 531 can effectively cause viscous damping for vibration components distributed in the frequency band from “9 hz” to “11 hz”.

<Third Embodiment>
The designer can design various vibration control devices based on the design principle described in connection with the above-described embodiment. In the third embodiment, an exemplary vibration control device is described.

  FIG. 4 is a conceptual diagram of a control device 100B exemplified as the vibration control device of the third embodiment. The description of the second embodiment is applied to elements having the same reference numerals as those of the second embodiment. The control device 100B will be described with reference to FIGS.

  Similar to the second embodiment, the control device 100B includes a controller 500A. The description of the second embodiment is applied to the controller 500A.

  The control device 100B includes a column shaft 210B, an intermediate shaft 220B, a rack 231B, a pinion rod 232B, a motor 300B, an encoder 400B, a torque sensor 600, a front subframe 710, a pair of suspension devices 720, And a pair of tie rods 730.

  The column shaft 210B is a rod-like member that extends downward from the steering wheel STW. Similar to the first embodiment, the column shaft 210B has a natural frequency Fcls. When the column shaft 210B receives rotational vibration about the longitudinal axis of the column shaft 210B at a frequency that matches the natural frequency Fcls, resonance occurs in the column shaft 210B.

  Torque sensor 600 is attached to column shaft 210B. When the driver rotates the steering wheel STW, torque corresponding to the steering force applied by the driver to the steering wheel STW is generated in the column shaft 210B. Torque sensor 600 detects torque generated in column shaft 210B. The torque sensor 600 then generates a torque signal representing the detected torque. The torque signal is output from the torque sensor 600 to the first torque determination unit 510 (see FIG. 2) of the controller 500A.

  The intermediate shaft 220 </ b> B includes a vertical rod 221 and two universal joints 222 and 223. The vertical rod 221 is erected substantially vertically. The universal joint 222 is attached to the upper end of the vertical rod 221. The universal joint 222 connects the upper end of the vertical rod 221 to the lower end of the column shaft 210B. The universal joint 223 is attached to the lower end of the vertical rod 221. The universal joint 223 connects the lower end of the vertical rod 221 to the pinion rod 232B.

  Similar to the first embodiment, the intermediate shaft 220B has a natural frequency Fims. When intermediate shaft 220B receives rotational vibration about the longitudinal axis of intermediate shaft 220B at a frequency that matches the natural frequency Fims, resonance occurs in intermediate shaft 220B.

  The pinion rod 232B corresponds to the pinion 232 described with reference to FIG. The description regarding the pinion 232 may be incorporated into the pinion rod 232B. The pinion rod 232B includes a pinion 233 and a connecting rod 234. The pinion 233 meshes with the rack 231B. The connecting rod 234 extends upward from the approximate center of the pinion 233 and is connected to the universal joint 223.

  The rack 231B extends between the pair of wheels WHL. The meshing mechanism formed by the rack 231B and the pinion rod 232B corresponds to the pinion rack mechanism 230 described with reference to FIG. The motor 300B is coupled to the rack 231B and applies assist torque to the rack 231B under the control of the controller 500A.

  Similar to the first embodiment, the meshing mechanism formed by the rack 231B and the pinion rod 232B has a natural frequency Fprm. When the motor 300B applies to the rack 231B a force that varies at a frequency that matches the natural frequency Fprm, the meshing mechanism formed by the rack 231B and the pinion rod 232B resonates.

  Encoder 400B is formed integrally with motor 300B. The encoder 400B generates an angle signal that represents the rotation angle of the motor 300B. The angle signal is output from the encoder 400B to the high-pass filter 531 (see FIG. 2) of the controller 500A. The encoder 400B corresponds to the angle detection unit 400 described with reference to FIG. The description regarding the angle detection unit 400 may be incorporated into the encoder 400B.

  The two tie rods 730 extend from both ends of the rack 231B. Two tie rods 730 are connected to two wheels WHL, respectively. In addition, the two tie rods 730 are also coupled to the two suspension devices 720, respectively. The linear motion of the rack 231B is transmitted to the two wheels WHL through the two tie rods 730. As a result, the directions of the two wheels WHL are changed.

  Each of the two tie rods 730 has a natural frequency Ftrd. When the motor 300B applies to the rack 231B a force that varies at a frequency that matches the natural frequency Ftrd, the tie rod 730 resonates.

  Each of the two suspension devices 720 has a natural frequency Fhng. When the motor 300B applies a force that varies at a frequency that matches the natural frequency Fhng to the rack 231B, the suspension device 720 resonates.

  The front sub-frame 710 is a lowermost frame at the front of the vehicle. An engine (not shown) is mounted on the front subframe 710. Each of the two suspension devices 720 is connected to the front subframe 710. In the present embodiment, the frame member is exemplified by the front subframe 710.

  The front subframe 710 has a natural frequency Ffsf. When a force that varies at a frequency that matches the natural frequency Ffsf is applied to the two suspension devices 720, the front subframe 710 resonates.

  The designers can use the column shaft 210B, the intermediate shaft 220B, the rack 231B, the pinion rod 232B, and the natural frequency Fcls, Fims, Fprm, Ftrd, Fhng, and Ffsf to be within the frequency range of “2hz”. The front subframe 710, the pair of suspension devices 720, and the pair of tie rods 730 may be designed. Alternatively, the designer may select column shaft 210B, intermediate shaft 220B, rack 231B, and natural frequency Fcls, Fims, Fprm, Ftrd, Fhng, Ffsf to be within the frequency range of “1hz”. The pinion rod 232B, the front subframe 710, the pair of suspension devices 720, and the pair of tie rods 730 may be designed.

<Fourth embodiment>
The motor described in connection with the third embodiment is connected to a rack. Alternatively, the motor may be coupled to the column shaft via a speed reducer. In a fourth embodiment, an exemplary vibration control device having a motor coupled to a column shaft is described.

  FIG. 5 is a conceptual diagram of a control device 100C exemplified as the vibration control device of the fourth embodiment. The description of the third embodiment is applied to elements having the same reference numerals as those of the third embodiment. The control device 100C will be described with reference to FIG.

  Similar to the third embodiment, the control device 100C includes a column shaft 210B, an intermediate shaft 220B, a rack 231B, a pinion rod 232B, an encoder 400B, a controller 500A, a torque sensor 600, and a front subframe 710. A pair of suspension devices 720 and a pair of tie rods 730. The description of the third embodiment is incorporated in these elements.

  The control device 100C further includes a motor 300C and a speed reducer 310. The reduction gear 310 is attached to the column shaft 210B. Motor 300C is coupled to reduction gear 310. The reducer 310 amplifies the assist torque input from the motor 300C with a predetermined reduction ratio. The amplified assist torque is transmitted from the speed reducer 310 to the column shaft 210B. The column shaft 210B is rotated by the amplified assist torque.

  Reducer 310 has a natural frequency Fsrd. When the motor 300C applies a force that fluctuates at a frequency that matches the natural frequency Fsrd to the speed reducer 310, the speed reducer 310 resonates.

  The designer may select the column shaft 210B, the intermediate shaft 220B, the rack 231B, and the pinion rod so that the natural frequencies Fcls, Fims, Fprm, Ftrd, Fhng, Ffsf, and Fsrd are within the frequency range of “2hz”. 232B, the reduction gear 310, the front subframe 710, the pair of suspension devices 720, and the pair of tie rods 730 may be designed. Alternatively, the designer may use the column shaft 210B, the intermediate shaft 220B, and the rack 231B so that the natural frequencies Fcls, Fims, Fprm, Ftrd, Fhng, Ffsf, and Fsrd are within the frequency range of “1 hz”. In addition, the pinion rod 232B, the speed reducer 310, the front subframe 710, the pair of suspension devices 720, and the pair of tie rods 730 may be designed.

<Fifth Embodiment>
The controller may instruct the motor of assist torque suitable for the speed of the vehicle on which the vibration control device is mounted. In the fifth embodiment, an exemplary vibration control device that instructs the motor on assist torque suitable for the vehicle speed will be described.

  FIG. 6 is a conceptual block diagram of a control device 100D exemplified as the vibration control device of the fifth embodiment. The description of the above-described embodiment is applied to elements having the same reference numerals as those of the above-described embodiment. The control device 100D will be described with reference to FIG.

  Similar to the third embodiment, the control device 100D includes a column shaft 210B, an intermediate shaft 220B, a rack 231B, a pinion rod 232B, a motor 300B, an encoder 400B, and a torque sensor 600. The description of the third embodiment is incorporated in these elements.

  The control device 100D further includes a controller 500D and a vehicle speed sensor 610. Similar to the second embodiment, the controller 500D includes a correction unit 530A and an adder 520A. The description of the second embodiment is incorporated in these elements.

  Controller 500D further includes a first torque determination unit 510D. First torque determination unit 510D includes a reading unit 511, a storage unit 512, and a low-pass filter 513. The vehicle speed sensor 610 determines the speed of the vehicle from the vehicle speed pulse. The vehicle speed sensor 610 generates a vehicle speed signal representing the determined vehicle speed. The vehicle speed signal is output from the vehicle speed sensor 610 to the reading unit 511.

  Torque sensor 600 detects the steering torque generated in column shaft 210B when the driver operates steering wheel STW. Alternatively, the torque sensor 600 may detect a steering torque generated in the intermediate shaft 220B.

  The torque sensor 600 generates a torque signal that represents the detected steering torque. The torque signal is output from the torque sensor 600 to the low pass filter 513. The low-pass filter 513 removes a high-frequency signal component (for example, a signal component having a frequency exceeding 7 hz) from the torque signal. As a result, noise that does not represent the driver's steering operation is removed. The torque signal after noise removal is output from the low pass filter 513 to the reading unit 511.

  The storage unit 512 stores information related to the first torque corresponding to the vehicle speed and the steering torque. The reading unit 511 reads the vehicle speed from the vehicle speed signal. The reading unit 511 reads the steering torque from the torque signal. The reading unit 511 reads the first torque corresponding to the read vehicle speed and steering torque from the storage unit 512. The reading unit 511 generates torque information representing the read first torque. The torque information is output from the reading unit 511 to the adder 520A. The storage unit 512 may be a general memory element. The reading unit 511 may be a CPU or other arithmetic element that executes a program designed for a process for reading data from a memory element and a signal generation process for generating a signal from the read data.

  FIG. 7 is a graph conceptually showing exemplary data stored in the storage unit 512. Data stored in the storage unit 512 will be described with reference to FIGS. 6 and 7.

  The horizontal axis of the graph in FIG. 7 represents the steering torque indicated by the torque signal output from the torque sensor 600. The vertical axis of the graph in FIG. 7 represents the first torque. The graph of FIG. 7 shows four curves corresponding to vehicle speeds of “10 km / h”, “30 km / h”, “80 km / h” and “150 km / h”. Each of the four curves represents a relationship between the steering torque and the first torque.

  When the vehicle speed is “80 km / h”, the vehicle speed sensor 610 generates a vehicle speed signal representing the vehicle speed of “80 km / h”. The vehicle speed signal is output from the vehicle speed sensor 610 to the reading unit 511 through the low pass filter 513.

  As described above, the torque sensor 600 detects the steering torque generated in the column shaft 210B. If the steering torque is “8 Nm”, the torque sensor 600 generates a torque signal representing the steering torque of “8 Nm”. The torque signal is output from the torque sensor 600 to the reading unit 511.

  The reading unit 511 reads the first torque corresponding to the vehicle speed of “80 km / h” and the steering torque of “8 Nm” from the storage unit 512. Regarding FIG. 7, the first torque corresponding to the vehicle speed of “80 km / h” and the steering torque of “8 Nm” is “40 Nm”. The reading unit 511 generates torque information representing the first torque of “40 Nm”. Torque information is output to adder 520A.

  As described in relation to the second embodiment, the adder 520 </ b> A receives the correction signal from the correction value calculation unit 532. The adder 520A corrects the torque information using the correction signal and determines the assist torque. The motor 300B outputs the determined assist torque to the rack 231B under the control of the controller 500D.

<Sixth Embodiment>
The correction technique described in connection with the above-described embodiment may deteriorate the tracking performance of the steering mechanism to the driver's operation on the steering wheel. Therefore, the correction process may be invalidated for a signal having a frequency at which the risk of resonance of the steering mechanism is sufficiently low. In the sixth embodiment, a technique for invalidating correction processing in a predetermined frequency band will be described.

  FIG. 8 is a conceptual block diagram of a control device 100E exemplified as the vibration control device of the sixth embodiment. The description of the fifth embodiment is applied to elements having the same reference numerals as those of the fifth embodiment. The control device 100E is described with reference to FIGS.

  Similar to the fifth embodiment, the control device 100E includes a column shaft 210B, an intermediate shaft 220B, a rack 231B, a pinion rod 232B, a motor 300B, an encoder 400B, a torque sensor 600, a vehicle speed sensor 610, Is provided. The description of the fifth embodiment is incorporated in these elements.

  The control device 100E further includes a controller 500E. Similar to the fifth embodiment, the controller 500E includes a first torque determination unit 510D and an adder 520A. The description of the fifth embodiment is incorporated in these elements.

  The controller 500E further includes a correction unit 530E and a current supply unit 540. Similar to the fifth embodiment, the correction unit 530E includes a correction value calculation unit 532. The description of the fifth embodiment is incorporated in the correction value calculation unit 532.

  The correction unit 530E includes a high pass filter 531E and an adjustment unit 533. The high pass filter 531E has a frequency characteristic represented by the Bode diagram described with reference to FIG. The high pass filter 531E performs the calculation described in connection with the second embodiment. The calculation result is output from the high pass filter 531E to the adjustment unit 533.

  FIG. 9 is a graph conceptually showing gain data stored in the adjustment unit 533. The control device 100E is further described with reference to FIG. 3, FIG. 8, and FIG.

  The designer who designs the control device 100E sets a value of “0” in the gain data stored in the adjustment unit 533 for the signal component in the frequency band from “0 hz” to “Xhz (<9 hz)”. Since the adjustment unit 533 multiplies the signal component in the frequency band from “0 hz” to “Xhz (<9 hz)” by the gain of the value “0”, the frequency band from “0 hz” to “Xhz (<9 hz)” Correction for signal components is disabled.

  The designer can determine the value of “X” as the value of the frequency at which the risk of resonance of the column shaft 210B, the intermediate shaft 220B, the pinion rod 232B, and the rack 231B is sufficiently low. As described in relation to the second embodiment, the natural frequencies of the column shaft 210B, the intermediate shaft 220B, the pinion rod 232B, and the rack 231B are distributed in the frequency band from “9 hz” to “11 hz” (FIG. 3). The adjustment unit 533 holds a gain of “1” for a frequency band of “9 hz” or higher. Since the adjustment unit 533 multiplies the signal component in the frequency band of “9 hz” or higher by a gain of “1”, the calculation result of the high-pass filter 531E for the signal component in the frequency band of “9 hz” or higher The correction value calculation unit 532 outputs it as it is.

  Regarding the frequency band from “Xhz” to “9 hz”, the gain held by the adjustment unit 533 monotonously increases. The designer may determine the value of “X” so that there is no sudden change in the control characteristics of the controller 500E between the frequency band of “Xhz” or lower and the frequency band of “9hz” or higher. .

  The adjustment unit 533 multiplies the calculation result from the high-pass filter 531E by the gain shown in FIG. 9 to correct the angle signal. Similar to the second embodiment, the correction value calculation unit 532 converts the corrected angle signal into a correction signal representing torque. The correction signal is output from the correction value calculation unit 532 to the adder 520A. The adder 520A corrects the torque information output from the reading unit 511 using the correction signal, and determines the assist torque.

  Information representing the determined assist torque is output from the adder 520A to the current supply unit 540. The current supply unit 540 determines the magnitude of the current supplied to the motor 300B based on information representing the assist torque. The conversion process from the assist torque to the current value depends on the input / output characteristics of the motor 300B. Therefore, the principle of this embodiment is not limited to a specific calculation process for calculating the current value from the assist torque.

  The current supply unit 540 supplies the determined value of current to the motor 300B. The motor 300B outputs an assist torque according to the supplied current. The assist torque is output to the rack 231B. The current supply unit 540 may be a current generation circuit designed to generate a current. The current generation circuit may include a CPU that executes a program designed for conversion processing from assist torque to a current value and a power source that outputs electric power.

  The principles of the various embodiments described above may be combined or modified to suit the requirements for the vehicle. Some of the various features described in connection with one of the various embodiments described above may be applied to the vibration control apparatus described in connection with another embodiment.

  The principle of the above-described embodiment is preferably used for various vehicle designs.

100, 100A to 100E ... Control device 200 ... Steering mechanism 210, 210B ... ..... Column shafts 220, 220B .... Intermediate shaft 230 ...・ Pinion rack mechanism 231 and 231B ・ ・ ・ ・ ・ ・ Rack 232 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pinion 232B ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pinion rod 300, 300B, 300C ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Motor 400 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・.... Angle detection unit 400B ... Encoders 500, 500A, 500D, 500E ... Controllers 510, 510D ..... First torque determining unit 520 ... Torque determination unit 520A .................. Adders 530, 530A, 530E ... Correction units 531, 531E ... High pass filter 532 ... Correction value calculation unit 710 ... ... Front subframe 720 ... Suspension device 730 ... ...... Tie rod STW ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Steering wheel WHL ・ ・ ・ ・ ・ ・ ・ ・ ・ ・Wheel

Claims (7)

A steering mechanism that performs a steering operation to change the direction of the pair of wheels;
A motor that provides the steering mechanism with an assist torque for assisting the steering operation;
An angle signal generation unit for generating an angle signal representing a rotation angle of the motor;
A controller for controlling the motor in accordance with the angle signal,
The steering mechanism includes a column shaft extending from a steering wheel, a pinion rack mechanism having a rack extending between the pair of wheels and a pinion meshing with the rack, and an intermediate shaft connecting the column shaft and the pinion. And including
The frequency range between the largest natural frequency and the smallest natural frequency among the column shaft, the pinion rack mechanism and the intermediate shaft is less than 2 hz,
The controller includes a first torque determining unit that determines a first torque from a steering torque generated in the steering mechanism under the rotation of the steering wheel, a correcting unit that determines a correction value for the first torque, and the correction value. And a second torque determining unit that corrects the first torque and determines the assist torque using
The angle signal includes a plurality of signal components that vibrate at a frequency within the frequency range,
The correction unit multiplies the plurality of signal components with a specific high gain, processes the angle signal, and determines the correction value. The vibration control device according to claim 1, wherein the correction unit processes the angle signal so that one phase of the plurality of signal components advances by 90 °, and determines the correction value. The correction unit multiplies the plurality of signal components by the gain, and processes the angle signal so that one phase of the plurality of signal components advances by 90 ° to generate a corrected angle signal. A high-pass filter that performs correction, and a correction value calculation unit that calculates a correction amount for the first torque from the corrected angle signal as the correction value,
The vibration control apparatus according to claim 1, wherein the second torque determination unit includes an adder that adds the correction amount calculated by the correction value calculation unit to the first torque and determines the assist torque. The vibration control device according to claim 3, wherein a natural angular frequency of a transfer function of the high-pass filter is set in the frequency range. The vibration control device according to claim 4, wherein the damping constant of the transfer function is set so that a peak appears in the frequency range. A frame member;
A pair of tie rods respectively connecting the rack and the pair of wheels;
A pair of suspension devices for suspending the pair of tie rods from the frame member;
6. The vibration control device according to claim 1, wherein each of the frame member, the pair of tie rods, and the pair of suspension devices has a natural frequency within the frequency range. The vibration control apparatus according to claim 1, wherein the frequency range is 1 hz or less.

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