KR20180069972A - Control method for in-wheel motor of vehicle and control system for the same - Google Patents

Abstract

The present invention relates to a control method for an in-wheel motor of a vehicle and a control system thereof, wherein the method comprises: a receiving step of receiving an acceleration signal by a control portion from an acceleration sensor measuring acceleration with respect to a reduction gear of an in-wheel motor; an abnormality determination step of determining whether or not the reduction gear has abnormality by analyzing the acceleration signal in accordance with a frequency by the control portion; and a notification step of notifying the abnormality to a driver of the vehicle by the control portion if the reduction gear is determined to be abnormal in the abnormality determination step.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-wheel motor control method for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an in-wheel motor of a vehicle and a control system thereof, and more particularly to an abnormal condition diagnosis of a reduction gear of an in-wheel motor mounted on a wheel of a vehicle.

An in-wheel motor is a motor mounted on a wheel of a vehicle, and is a drive source provided to directly apply rotational force to the wheel. When an in-wheel motor is provided in a vehicle, a reduction gear can be provided in consideration of the limitations of the drive region and the like.

In a vehicle equipped with an in-wheel motor, the motor can be provided on the knuckle side of the wheel. Since the in-wheel motor is located on the wheel side rather than inside the vehicle body, wear and breakage of the in- The progress of the durability can be fast.

Accordingly, it is an important issue in the maintenance and management of the vehicle equipped with the in-wheel motor that the abnormal state of the gear structure forming the engagement relationship with the in-wheel motor and the in-wheel motor is efficiently and highly reliable.

It should be understood that the foregoing description of the background art is merely for the purpose of promoting an understanding of the background of the present invention and is not to be construed as an admission that the prior art is known to those skilled in the art.

KR 10-2012-0095605 A1

An object of the present invention is to provide a vehicle equipped with an in-wheel motor capable of efficiently and reliably detecting an abnormal state of a reduction gear of the in-wheel motor to improve the maintenance and repairability of the vehicle and effectively secure the stability of the vehicle have.

According to another aspect of the present invention, there is provided a method of controlling an in-wheel motor of a vehicle, the method comprising: receiving an acceleration signal from an acceleration sensor for measuring an acceleration of the reduction gear of the in-wheel motor; Wherein the control unit analyzes the acceleration signal according to a frequency to determine whether the reduction gear is in an abnormal state; And an informing step of informing the driver of the vehicle of the abnormal state when the control unit determines that the speed reducer corresponds to the abnormal state in the abnormality determination step.

In the abnormality determination step, when the acceleration signal corresponding to the abnormal state is observed more than the reference number within the reference time, the control unit can determine the reduction gear as the abnormal state.

In the abnormality determination step, the controller may analyze the amplitude of the acceleration signal with respect to a specific frequency to determine whether the reduction gear is in the abnormal state.

Wherein the specific frequency includes at least one of a shaft rotation frequency of the reduction gear, an engagement frequency of the reduction gear, a side lobe frequency with respect to the engagement frequency, a harmonic frequency corresponding to an integral multiple of the engagement frequency, At least one of the vibration frequencies may be included.

Wherein the abnormality determination step determines that the control unit determines that the reduction gear is in a damaged state during the abnormal state of the reduction gear when the amplitude of the acceleration signal with respect to the shaft rotation frequency is equal to or greater than a first reference value; . ≪ / RTI >

In the value damage determination process, the control unit receives the motor RPM information from the resolver of the in-wheel motor, and determines the shaft rotation frequency of the reduction gear from the motor RPM.

The abnormality determining step may include a wear determining step of determining that the reduction gear is in a wear state of the reduction gear when the amplitude of the acceleration signal with respect to the natural vibration frequency is equal to or greater than a second reference value can do.

Wherein when the amplitude of the acceleration signal with respect to the natural frequency is greater than the second reference value and the amplitude with respect to the side lobe frequency is equal to or greater than a third reference value in the acceleration signal, It can be judged that the gear is worn.

Wherein when the amplitude of the acceleration signal with respect to a plurality of side lobe frequencies at a frequency equal to or higher than the engagement frequency is observed in the acceleration signal, the control unit determines that the speed reducer is eccentric with respect to the central axis And an eccentricity judgment process.

Wherein the abnormality determination step determines whether or not an axial fault condition in which the center axis alignment state of the reduction gear is determined to be a poor axis state in the abnormal state during the abnormal state when the amplitude of the harmonic frequency with respect to the harmonic frequency is equal to or greater than a fourth reference value Process.

According to another aspect of the present invention, there is provided an in-wheel motor control system for a vehicle, including: an in-wheel motor mounted on a knuckle housing; A planetary gear set coupled to an output shaft of the in-wheel motor; A reduction gear meshed with the planetary gear set and adapted to transmit the power of the in-wheel motor to the wheels; An acceleration sensor configured to measure an acceleration of the reduction gear; A resolver adapted to measure a motor RPM of the in-wheel motor; And a controller for receiving the acceleration signal from the acceleration sensor and receiving the motor RPM information from the resolver to determine the shaft rotation frequency of the reduction gear, and when the amplitude of the acceleration signal with respect to the shaft rotation frequency is equal to or greater than a first reference value, The amplitude of the reduction gear relative to the natural frequency of the reduction gear is not less than the second reference value and the amplitude at the side lobe frequency with respect to the meshing frequency of the reduction gear is determined Is determined as an eccentric state of the reduction gear when the amplitude with respect to a plurality of side lobe frequencies is observed at a frequency equal to or higher than the engagement frequency in the acceleration signal, Wherein the acceleration signal includes a harmonic corresponding to an integral multiple of the engagement frequency If the amplitude for a frequency not less than the fourth reference value, and determines a failure condition of the reduction gear shaft, the control provided to inform the abnormality to the driver of the vehicle, if applicable to the reduction gear eoga the abnormality; includes.

As described above, according to the present invention, in the vehicle equipped with the in-wheel motor, the abnormal state of the reduction gear of the in-wheel motor can be grasped efficiently and reliably to improve the maintenance and repairability of the vehicle and effectively secure the stability of the vehicle .

In particular, the present invention is advantageous in that the abnormal state of the reduction gear can be grasped effectively and reliably by analyzing the acceleration signal for the reduction gear of the in-wheel motor according to the frequency.

Further, the present invention can classify the detailed abnormal state of the reduction gear by analyzing the amplitude of the acceleration signal with respect to a specific frequency, so that the maintenance of the gear structure equipped with the in-wheel motor is improved, The safety of the vehicle is secured.

Further, according to the present invention, the shaft rotation frequency, the engaging frequency, the side lobe frequency, the harmonic frequency and the natural vibration frequency of the reduction gear are used as the specific frequency, and the damage of the reduction gear, So that the manageability is particularly improved.

1 is a flowchart showing a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention,
FIG. 2 is a graph showing a steady state frequency-dependent acceleration signal in a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention,
FIG. 3 is a graph showing frequency-dependent acceleration signals of a damaged state in a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention,
4 is a graph showing frequency-dependent acceleration signals in a wear state in a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention,
5 is a graph showing frequency-dependent acceleration signals in an eccentric state in a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention,
FIG. 6 is a graph showing frequency-dependent acceleration signals of the shaft failure state in the in-wheel motor control method of the vehicle according to the embodiment of the present invention,
FIG. 7 is a graph showing a steady state frequency-dependent acceleration signal with respect to a change in motor RPM in a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention;
FIG. 8 is a graph showing frequency-based acceleration signals measured for changes in motor RPM in a method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention;
9 is a view showing an in-wheel motor control system of a vehicle according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 to 9, a method for controlling an in-wheel motor of a vehicle according to the present invention includes a step of receiving an acceleration signal from an acceleration sensor 192, which measures the acceleration of the reduction gear 180 of the in-wheel motor, (S100); An abnormality determination step (S200) of the controller (200) to analyze the acceleration signal according to frequency to determine whether the reduction gear (180) is abnormal; And an informing step S300 of informing the driver of the vehicle of the abnormal state when the control unit 200 determines that the reduction gear 180 is in the abnormal state in the abnormality determining step S200 do.

Specifically, it is as follows. The controller 200 receives the acceleration signal from the acceleration sensor 192 that measures the acceleration of the in-wheel motor 140 relative to the reduction gear 180 in the receiving step S100.

In the present invention, the in-wheel motor 140 is mounted on the wheel side of the vehicle, preferably, it can be inserted into the knuckle housing 120 of the wheel. Also, in the present invention, a reduction gear 180 is provided on the path for transmitting the driving force from the in-wheel motor 140 to the wheel.

In particular, the present invention determines the abnormal state of the reduction gear (180). The acceleration sensor 192 measures the acceleration of the reduction gear 180 and transmits the acceleration to the controller 200. The acceleration sensor 192 is preferably mounted to the knuckle housing 120, and may be provided at various positions as required.

Meanwhile, in the abnormality determination step S200, the controller 200 analyzes the acceleration signal according to the frequency to determine whether the reduction gear 180 is abnormal.

The reduction gear 180 can preferably form a meshing relationship with another gear on the side of the in-wheel motor 140 and more preferably can engage with the planetary gear set 160 provided on the side of the in- .

The acceleration signal of the reduction gear 180 is observed by combining signals having various frequencies. If it is determined that the acceleration signal is abnormal, it is determined that the reduction gear 180 is in an abnormal state, and the present invention determines the abnormal state of the reduction gear 180 using the determination result.

The abnormal state of the reduction gear 180 may vary. Preferably, the abnormal state may include tooth damage, abrasion, eccentricity, defective axial alignment, etc. of the reduction gear 180, and the present invention may be applied to an analysis of the abnormal state of the reduction gear 180, .

The steady state of the reduction gear 180 may show a specific frequency-dependent acceleration signal pattern. However, when an abnormal state occurs, the acceleration signal has a different pattern from the normal pattern, and the control unit 200 analyzes the abnormal state to determine the abnormal state of the reduction gear 180.

If it is determined in step S200 that the reduction gear 180 is in the abnormal state, the control unit 200 informs the driver of the vehicle of the abnormal state in step S300.

The in-wheel motor 140 is more susceptible to the outside of the vehicle body than the motor mounted inside the vehicle body, and thus the endurance progression such as abrasion or the occurrence of an abnormal condition can easily occur. The present invention seeks to grasp the abnormal state of the vehicle equipped with the in-wheel motor 140 effectively and accurately.

In the case where the reduction gear 180 of the in-wheel motor 140 is abnormal, maintenance and repair are required. In the present invention, the control unit 200 informs the driver of the abnormal state, I want to solve it.

The manner in which the driver is informed of the abnormal condition may vary. The abnormal state of the in-wheel motor 140 (particularly, the reduction gear 180) can be informed to the driver by lighting the warning lamp on the side of the in-wheel motor 140 on the cluster (instrument panel) provided in the vehicle interior.

The in-wheel motor 140 may have a plurality of gears connected to the in-wheel motor 140. If necessary, the reduction gear 180 It is possible to diagnose an abnormal condition according to the present invention.

The drawings for explaining the present invention are as follows. 1 is a flowchart showing a control method for an abnormality diagnosis of an in-wheel motor 140 according to the present invention. 2 is a graph showing the acceleration signal of the reduction gear 180 in a steady state in the present invention.

Referring to FIG. 2, it can be seen that acceleration signals in which various frequency-dependent signals are combined are classified and displayed according to frequency (for example, amplitude is separated for each frequency by Fourier conversion or the like).

In addition, as described below, the present invention can set a specific frequency for diagnosing an abnormal state with respect to various gears (particularly, the reduction gear 180) provided on the in-wheel motor 140 side, And can be filtered.

FIG. 2 shows the amplitudes of specific frequencies to be judged in order to diagnose an abnormal condition of the reduction gear 180 of the in-wheel motor 140. Since this is related to the steady state as described above, it can be a criterion for determining the abnormal state.

3 to 6 show various acceleration signals that can be observed in the abnormal state of the reduction gear 180. [ The graphs shown in FIGS. 3 to 6 show different states, and it can be seen that they are different from FIG. 2 corresponding to the steady state.

3 to 6, the present invention can accurately and efficiently analyze the abnormal state of the reduction gear 180 and the like with respect to the in-wheel motor 140 as the acceleration signal having a difference from the steady state is observed.

7 shows an acceleration signal according to the motor RPM (RPM of the in-wheel motor 140). Frequency amplitudes of the acceleration signals with respect to the acceleration signals are displayed in the respective motor RPMs, and the abnormal state of the reduction gears 180 and the like can be grasped by the motor RPM using the data shown in FIG.

8 shows data of acceleration signals actually measured for each motor RPM. It can be understood that the data is filtered based on the data shown in Fig. The present abnormal state of the reduction gear 180 and the like can be efficiently analyzed based on the filtered data as shown in FIG.

9 is a schematic view of an in-wheel motor control system according to the present invention. 9, the various gears including the in-wheel motor 140 and the reduction gear 180 are shown in the knuckle housing 120. The present invention can be applied to the reduction gear 180, do. Such a control system can be referred to in understanding the control method according to the present invention and will be described in detail below.

In the meantime, in the in-wheel motor control method of a vehicle according to an embodiment of the present invention, when the acceleration signal corresponding to the abnormal state is observed more than the reference number within the reference time in the abnormality determination step (S200) And determines that the reduction gear 180 is in the abnormal state.

In the present invention, a criterion for determining whether the acceleration signal indicates an abnormal state of the reduction gear 180 may be preset, and the acceleration signal may indicate a signal temporarily corresponding to an abnormal state due to various causes .

Accordingly, the embodiment of the present invention determines whether the acceleration signal indicating the abnormal state is observed more than the reference number within the reference time, in order to determine whether the acceleration signal is a situation indicating the noise-related abnormality state signal.

The reference time and the reference number may be determined in various values in various ways, and may be set based on experimental results.

The embodiment of the present invention determines that the deceleration ear 180 is in the abnormal state when the acceleration signal indicating the abnormal state of the reduction gear 180 is observed more than the reference number within the reference time, And determines the abnormal state of the reduction gear 180 stably.

2 to 6 and 9, in the in-wheel motor control method for a vehicle according to the embodiment of the present invention, the abnormality determination step S200 may be such that the controller 200 calculates the amplitude of a specific frequency And determines whether the reduction gear 180 is in the abnormal state.

Specifically, in the present invention, the information for determining the abnormal state of the reduction gear 180 and the like can be specified by the amplitude with respect to a specific frequency of the acceleration signal. For example, the specific frequency may be determined according to the frequency that can be derived from other design aspects such as the rotational speed of the reduction gear 180 according to the current motor RPM, the number of gear teeth, and the like.

That is, with respect to the reduction gear 180 or the like to be subjected to the abnormal state determination in the embodiment of the present invention, the frequencies on the acceleration signal for which analysis is required to determine an abnormal state are defined as specific frequencies.

The reduction gear 180 and the like repeating the same behavior generate a specific and repetitive signal even in the acceleration signal, which can be predicted with an amplitude for a specific frequency.

However, the reduction gear 180 or the like, which is in an abnormal state and deviates from the behavior in the steady state, generates an acceleration signal different from the steady state for a specific frequency. The embodiment of the present invention, It is possible to accurately analyze the abnormal state of the reduction gear 180 and the like.

2 to 6 show the amplitudes for specific frequencies that can be presented for determining the abnormal state of the reduction gear 180 and the like in the embodiment of the present invention. FIG. 9 is a control system for an embodiment of the present invention, and can be referred to in understanding embodiments of the present invention.

2 to 6 and 9, in the method of controlling an in-wheel motor of a vehicle according to an embodiment of the present invention, the specific frequency may include an axis rotation frequency of the reduction gear 180, an engagement frequency of the reduction gear 180, A harmonic frequency corresponding to an integral multiple of the engaging frequency, and a natural frequency of the reduction gear 180 that is determined by design.

Each of these specific frequencies will be described in detail as follows. First, the shaft rotation frequency is a frequency specified in accordance with the rotation speed of the reduction gear 180 or the like for which an abnormal state determination is required.

The axis rotation frequency can be a measure for determining a particular frequency for which analysis is required to determine an abnormal condition. The acceleration signal varies depending on the rotational speed of the motor RPM or the reduction gear 180 of the in-wheel motor 140. In order to grasp the current situation and to determine the specific frequency, in the embodiment of the present invention, The frequency can be defined.

The engagement frequency corresponds to the frequency generated from the impact of the gear teeth of the reduction gear 180 for which an abnormal state grasp is required. That is, by multiplying the shaft rotation frequency for the current rotation speed by the gear size formed on the reduction gear 180, the engagement frequency is determined.

Since the common characteristics that can be generated at the gear teeth of the reduction gear 180 can be reflected at the engagement frequency, in particular, the gear wear state can be analyzed.

Meanwhile, the side lobe frequency in the present invention is a frequency determined for the meshing frequency. The side wave frequency may correspond to a frequency value obtained by adding or subtracting an integral multiple of the axial rotation frequency with respect to the engagement frequency. Generally, the amplitude at the side lobe frequency is generated so as to form a pair, one at each of above and below the above-mentioned engaging frequency.

According to the above definition, the side lobe frequency may be measured in a plurality of pairs with respect to the meshing frequency. For example, amplitudes can be generated at a plurality of frequencies that are different from each other by an integral multiple of the axis rotation frequency added to or subtracted from the meshing frequency. (FIG. 5 shows a graph in which the amplitude is formed at two pairs of side major frequencies. )

Also, in the embodiment of the present invention, the harmonic frequency means a frequency corresponding to an integral multiple of the engaging frequency. The harmonic frequency may be generated as an integral multiple of the engaging frequency when an unexpected signal is generated in the rotation of the reduction gear 180. In an embodiment of the present invention, It is possible.

On the other hand, the natural frequency of the reduction gear 180 is a frequency at which the natural frequency of the reduction gear 180 is reflected.

Figures 2 to 6 show the amplitudes of various specific frequencies according to an embodiment of the present invention. In particular, FIG. 4 shows the amplitude at the natural frequency, FIG. 5 shows the side-by-side frequency with a plurality of pairs of amplitudes, and FIG. 6 shows the amplitude of the harmonic frequency have. FIG. 9 is a control system for an embodiment of the present invention, and can be referred to in understanding embodiments of the present invention.

2 to 3 and 9, in the in-wheel motor control method for a vehicle according to the embodiment of the present invention, the abnormality determining step S200 may be configured such that the amplitude of the acceleration signal with respect to the shaft rotation frequency is a first reference value The control unit 200 determines that the reduction gear 180 is damaged during the abnormal state of the reduction gear 180 in step S210.

In the case where the gear teeth of the reduction gear 180 are damaged, for example, when at least a part of the gear teeth is broken, it does not affect the acceleration signal by the gear teeth, The amplitude is affected.

This can be predicted theoretically, but can also be confirmed through experimental results. In the embodiment of the present invention, when the amplitude of the shaft rotation frequency is equal to or greater than the first reference value, at least a part of the gear teeth of the reduction gear 180 is judged to be damaged.

In the present invention, the abnormal state of the reduction gear 180 may include a tooth-damaged state, a wear state, an eccentric state, and an axial fault state, and an abnormal state other than the tooth-damaged state will be described below.

On the other hand, the first reference value may be determined in various ways, but it may be determined preferably by taking a statistical method on the results derived (experimentally) based on the measured results. The concrete values can be variously determined from a strategic point of view.

2 is an acceleration signal generated in the reduction gear 180 in a steady state, and FIG. 3 is an acceleration signal generated in the reduction gear 180 in a particularly damaged state. In particular, in the graphs of FIGS. 2 and 3, the amplitude of the shaft rotation frequency is significantly increased in FIG. 3 compared with FIG.

As described above, by analyzing the acceleration signal of the reduction gear 180 with respect to the shaft rotation frequency, it is possible to grasp the abnormal state of the reduction gear 180 in the embodiment of the present invention efficiently and reliably. FIG. 9 is a control system for an embodiment of the present invention, and can be referred to in understanding embodiments of the present invention.

9, in the in-wheel motor control method for a vehicle according to the embodiment of the present invention, in the step S210, the controller 200 controls the in-wheel motor of the vehicle from the resolver 194 of the in- Receives the RPM information, and determines the shaft rotation frequency of the reduction gear (180) from the motor RPM.

The shaft rotation frequency is a value determined on the basis of the speed at which the reduction gear 180 rotates about the central axis (or the number of revolutions per unit time), which can be derived through the rotation speed or the RPM of the reduction gear 180 The control unit 200 receives the motor RPM information from the resolver 194 that measures the motor RPM of the in-wheel motor 140. The control unit 200 receives the motor RPM information from the motor RPM via the gear ratio, Determine RPM or rotational speed.

Thus, the rotation speed of the reduction gear 180 is measured from the resolver 194 of the in-wheel motor 140, which is provided for the control of the in-wheel motor 140, without addition of a sensor for measuring the rotation speed or RPM of the reduction gear 180 It is possible to determine the shaft rotation frequency for the reduction gear 180 via the motor RPM. 9, a resolver 194 provided for measuring the motor RPM of the in-wheel motor 140 is schematically shown.

2, 4, and 9, in the in-wheel motor control method for a vehicle according to the embodiment of the present invention, the abnormality determining step S200 may be configured such that, in the acceleration signal, The control unit 200 determines that the reduction gear 180 is in a wear state during an abnormal state of the reduction gear 180 (S220).

The reduction gear 180 may form a meshing relationship with another gear other than the reduction gear 180. When the reduction gear 180 is worn and its abrasion level becomes a certain level or more, The amplitude is generated over the second reference value.

Based on the measured results, the embodiment of the present invention can determine the wear state of the reduction gear 180 by analyzing the amplitude of the natural frequency. The second reference value is a measure for determining the wear level of the gear which can be defined as the wear state set in the embodiment of the present invention as an abnormal state of the reduction gear 180. [

Therefore, the second reference value can be variously determined in consideration of a strategic aspect based on experimental and statistical results (for example, when the safety of the gear is to be improved, the second reference value can be changed to a lower value will be.)

The embodiment of the present invention can efficiently grasp the wear state of the reduction gear 180 in the abnormal state by analyzing the amplitude of the acceleration signal with respect to the natural vibration frequency of the reduction gear 180 as described above.

4 shows an acceleration signal for the case where the reduction gear 180 corresponds to a wear state as an abnormal state. In FIG. 2 corresponding to the measured acceleration signal when the reduction gear 180 is in a steady state, the amplitude with respect to the natural vibration frequency of the reduction gear 180 is not observed, but in FIG. 4, the amplitude is formed at the natural vibration frequency can confirm. FIG. 9 is a control system for an embodiment of the present invention, and can be referred to in understanding embodiments of the present invention.

2, 4, and 9, in the in-wheel motor control method of a vehicle according to the embodiment of the present invention, the wear determination process (S220) determines whether or not the amplitude of the acceleration signal, The control unit 200 determines that the reduction gear 180 is in a wear state when the amplitude of the side lobe wave frequency is equal to or greater than the third reference value.

Specifically, in the embodiment of the present invention, in addition to the natural vibration frequency, the amplitude of the side lobe frequency is additionally determined in the determination of the wear state.

As the wear of the reduction gear 180 progresses, the amplitude of the side lobe frequency with respect to the meshing frequency becomes larger. In the embodiment of the present invention, the amplitude of the side lobe frequency is compared with the third reference value to determine the wear state.

The third reference value may also be determined in view of the strategic aspects of experimental and statistical results. As a result, the present invention can more reliably and effectively determine the wear state of the reduction gear 180 by analyzing the amplitude at the side lobe frequency as well as the natural vibration frequency.

4, it can be seen that the amplitude of the side lobe frequency is increased compared to the graph of Fig. 2 corresponding to the steady state. When the amplitude of the natural frequency and the amplitude of the side lobe frequency are equal to or greater than the second reference value and the third reference value You can see that it is applicable. FIG. 9 is a control system for an embodiment of the present invention, and can be referred to in understanding embodiments of the present invention.

2, 5, and 9, in the in-wheel motor control method for a vehicle according to the embodiment of the present invention, the abnormality determination step S200 includes a step of determining, in the acceleration signal, The eccentricity determining step S230 in which the controller 200 determines that the reduction gear 180 is eccentric with respect to the center axis during the abnormal state.

The acceleration signal of the reduction gear 180 is set such that the amplitude of the plurality of side lobe frequencies at the above engagement frequency is equal to or less than the above- Lt; / RTI > The state in which the amplitude is observed at a plurality of side lobe frequencies as described above is determined as the eccentric state of the reduction gear 180. [

Preferably, the amplitudes of the side lobe frequencies are observed based on the meshing frequency. If the amplitude is generated in any one side lobe frequency in which no amplitude is generated in the steady state, It is determined to be the eccentric state.

Referring to FIG. 5, an acceleration signal that may appear in the eccentric state of the reduction gear 180 is shown. In FIG. 2, it can be seen that the amplitude is formed at a pair of side major frequencies with the centering of the coupling frequency. Referring to FIG. 5, it can be seen that the amplitude is formed at two pairs of side major frequencies around the coupling frequency.

5, when an amplitude is formed at a pair of side lobe frequencies at which no amplitude is generated in a steady state, the embodiment of the present invention includes an eccentric state of the reduction gear 180 (including the case where excessive backlash exists .

The acceleration signal spectrum of FIG. 5 is one of various examples that can be observed in the eccentric state, and the amplitude may be formed at two or more pairs of side lobe frequencies. In another embodiment of the present invention, It is possible to determine whether or not the eccentric state exists.

2, 6, and 9, in the in-wheel motor control method for a vehicle according to the embodiment of the present invention, the abnormality determination step (S200) includes the step of determining whether the amplitude of the acceleration signal with respect to the harmonic frequency is a fourth reference value The control unit 200 determines that the center axis alignment state of the reduction gear 180 is in a poor axis state during the abnormal state (S240).

The acceleration signal of the reduction gear 180 is set to an integer multiple of the engagement frequency when the alignment state of the center shaft is poor due to the influence of the housing in which the center shaft of the reduction gear 180 or the reduction gear 180 is located, An amplitude is formed at the harmonic frequency.

Accordingly, in the embodiment of the present invention, the control unit 200 determines the shaft failure state of the reduction gear 180 based on whether the amplitude of the acceleration signal of the reduction gear 180 at the harmonic frequency is observed.

Further, in the embodiment of the present invention, when the amplitude of the harmonic frequency is equal to or higher than the fourth reference value, it is determined that the axis is in a defective state. Here, the fourth reference value is a case where the amplitude is formed at the harmonic frequency, .

That is, the embodiment of the present invention determines the abnormal state of the reduction gear 180 that actually corresponds to the shaft failure state through the fourth reference value. This fourth reference value can be determined on the basis of experimental results and is preferably determined as a value for judging whether the amplitude formation at the harmonic frequency is valid (this is not different from the second reference value for the natural frequency of oscillation).

Referring to FIG. 6, it can be seen that the amplitude is formed at the harmonic frequency. This difference can be clearly confirmed as compared with Fig. 2 corresponding to the steady state of the reduction gear 180. Fig.

9, an in-wheel motor control system for a vehicle according to an embodiment of the present invention includes an in-wheel motor 140 mounted on a knuckle housing 120; A planetary gear set 160 coupled to an output shaft of the in-wheel motor 140; A reduction gear 180 meshed with the planetary gear set 160 and adapted to transmit the power of the in-wheel motor 140 to the wheels; An acceleration sensor 192 configured to measure an acceleration of the reduction gear 180; A resolver 194 adapted to measure a motor RPM of the in-wheel motor 140; And an acceleration sensor 192 for receiving an acceleration signal from the resolver 194 and receiving motor RPM information from the resolver 194 to determine a shaft rotation frequency of the reduction gear 180. In the acceleration signal, And determines that the amplitude of the reduction gear (180) with respect to the natural vibration frequency of the reduction gear (180), which is determined in design in the acceleration signal, is equal to or greater than a second reference value And when the amplitude at the side lobe frequency with respect to the meshing frequency of the reduction gear (180) is equal to or greater than the third reference value, it is determined that the deceleration ear is in a wear state, and in the acceleration signal, And determines the eccentric state of the reduction gear (180) when the amplitude of the engagement frequency When the amplitude of the harmonic frequency corresponding to the integral multiple is equal to or greater than the fourth reference value, it is determined that the reduction gear 180 is in an abnormal state of the reduction gear 180. When the reduction gear 180 is in the abnormal state, And a control unit 200 for informing the user of the information.

Specifically, the in-wheel motor 140 is mounted on the knuckle housing 120. The knuckle housing 120 preferably forms a coupling with the wheel, and the knuckle housing 120 may be formed with a seating groove into which the in-wheel motor 140 is inserted. 9 shows an embodiment in which the mounting groove is formed in the knuckle housing 120 and the in-wheel motor 140 is inserted into the mounting groove.

The planetary gear set 160 is coupled to the output shaft of the in-wheel motor 140. In the planetary gear set 160, any one of the sun gear, the carrier, and the ring gear may be directly coupled to the output shaft of the in-wheel motor 140, and an additional gear may be provided in the in- The set 160 may be engaged and a spline may be formed on the output shaft of the in-wheel motor 140 to achieve spline coupling with the planetary gear set 160. [

Further, preferably, the planetary gear set 160 may reduce the rotational speed provided by the in-wheel motor 140 and increase the torque to transmit the torque to the wheel side. FIG. 9 shows a planetary gear set 160 that forms a coupling relationship with the output shaft of the in-wheel motor 140.

The reduction gear 180 is engaged with the planetary gear set 160 to transmit the power of the in-wheel motor 140 to the wheels. The reduction gear 180 is a means for transmitting torque to the wheel (wheel) side while reducing the rotational speed transmitted from the planetary gear set 160. [

The reduction gear 180 forms a meshing relationship with the planetary gear set 160. Specifically, it can form a meshing relationship with any one of the sun gear, carrier (or pinion gear) and ring gear of the planetary gear set 160. FIG. 9 shows a reduction gear 180 that meshes with the planetary gear set 160.

Meanwhile, the acceleration sensor 192 is provided to measure the acceleration of the reduction gear 180. The acceleration sensor 192 is also provided to measure the acceleration of the reduction gear 180, since the present invention performs the determination of the abnormal state with respect to the reduction gear 180 suitable for the understanding of the present invention.

The acceleration sensor 192 may be provided in various types, and its mounting position may also vary. Further, the acceleration sensor 192 may measure the acceleration of the reduction gear 180 directly or may measure the acceleration of the rotating body (for example, the planetary gear set 160) forming a connection with the acceleration sensor 192 And may be used for converting the acceleration into the acceleration of the reduction gear 180. [

On the other hand, the resolver 194 is provided to measure the motor RPM of the in-wheel motor 140. The resolver 194 may have various types and various mounting locations. The motor RPM may be converted to a rotation speed or RPM of the reduction gear 180 and utilized as an element for determining an abnormal state of the reduction gear 180. [

The control unit 200 receives the acceleration signal from the acceleration sensor 192 and receives the motor RPM information from the resolver 194 to determine the axis rotation frequency of the reduction gear 180, (180) is determined to be a damage state of the reduction gear (180) when the amplitude of the reduction gear (180) with respect to the shaft rotation frequency is equal to or greater than a first reference value, Is greater than or equal to a second reference value and an amplitude at a side lobe frequency with respect to an engaging frequency of the reduction gear (180) is equal to or greater than a third reference value, and determines that the deceleration ear The control unit determines the eccentric state of the reduction gear 180 when the amplitude of the plurality of side lobe frequencies is observed in the acceleration signal, If the amplitude of the harmonic frequency corresponding to an integer multiple of the engaging frequency is equal to or greater than the fourth reference value, it is determined that the reduction gear 180 is in the poor state. If the reduction gear 180 is in the abnormal state, So as to inform the abnormal state.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the following claims It will be apparent to those of ordinary skill in the art.

S100: Receiving step S200: Abnormal judgment step
S300: Notification step 120: Knuckle housing
140: In-wheel motor 160: Planetary gear set
180: reduction gear 200:

Claims (11)

A receiving step of the control unit receiving an acceleration signal from an acceleration sensor for measuring an acceleration of the reduction gear of the in-wheel motor;
Wherein the control unit analyzes the acceleration signal according to a frequency to determine whether the reduction gear is in an abnormal state; And
And an informing step of informing the driver of the vehicle of the abnormal state when the control unit determines that the speed reducer corresponds to the abnormal state in the abnormality determination step. The method according to claim 1,
Wherein the controller determines that the reduction gear is in the abnormal state when the acceleration signal corresponding to the abnormal state is observed more than the reference number within the reference time. The method according to claim 1,
Wherein the abnormality determination step determines the presence or absence of the abnormal state of the reduction gear by analyzing the amplitude of the acceleration signal with respect to a specific frequency of the control signal. The method of claim 3,
Wherein the specific frequency includes at least one of a shaft rotation frequency of the reduction gear, an engagement frequency of the reduction gear, a side lobe frequency with respect to the engagement frequency, a harmonic frequency corresponding to an integral multiple of the engagement frequency, Wherein the at least one of the vibration frequency and the vibration frequency is included. The method of claim 4,
Wherein the abnormality determination step determines that the control unit determines that the reduction gear is in a damaged state during the abnormal state of the reduction gear when the amplitude of the acceleration signal with respect to the shaft rotation frequency is equal to or greater than a first reference value; Wherein the in-wheel motor control method comprises the steps of: The method of claim 5,
Wherein the control unit receives the motor RPM information from the resolver of the in-wheel motor, and determines the shaft rotation frequency of the reduction gear from the motor RPM. The method of claim 4,
The abnormality determining step may include a wear determining step of determining that the reduction gear is in a wear state of the reduction gear when the amplitude of the acceleration signal with respect to the natural vibration frequency is equal to or greater than a second reference value Wherein the in-wheel motor control method comprises: The method of claim 7,
Wherein when the amplitude of the acceleration signal with respect to the natural frequency is greater than the second reference value and the amplitude with respect to the side lobe frequency is equal to or greater than a third reference value in the acceleration signal, And determining that the gear is in a wear state. The method of claim 4,
Wherein when the amplitude of the acceleration signal with respect to a plurality of side lobe frequencies at a frequency equal to or higher than the engagement frequency is observed in the acceleration signal, the control unit determines that the speed reducer is eccentric with respect to the central axis And an eccentricity determining process for determining an eccentricity of the vehicle. The method of claim 4,
Wherein the abnormality determination step determines whether or not an axial fault condition in which the center axis alignment state of the reduction gear is determined to be a poor axis state in the abnormal state during the abnormal state when the amplitude of the harmonic frequency with respect to the harmonic frequency is equal to or greater than a fourth reference value Wherein the step of controlling the in-wheel motor comprises the steps of: An in-wheel motor mounted on the knuckle housing;
A planetary gear set coupled to an output shaft of the in-wheel motor;
A reduction gear meshed with the planetary gear set and adapted to transmit the power of the in-wheel motor to the wheels;
An acceleration sensor configured to measure an acceleration of the reduction gear;
A resolver adapted to measure a motor RPM of the in-wheel motor;
Wherein the control unit receives the acceleration signal from the acceleration sensor, receives the motor RPM information from the resolver to determine the shaft rotation frequency of the reduction gear, and when the amplitude of the acceleration signal with respect to the shaft rotation frequency is equal to or greater than the first reference value, The amplitude of the acceleration signal is determined to be a value of the gear damage state and the amplitude of the reduction gear relative to the natural vibration frequency of the reduction gear determined in the acceleration signal is equal to or greater than a second reference value, And determines the eccentric state of the reduction gear as the eccentric state of the reduction gear when the amplitude with respect to a plurality of side lobe frequencies is observed at a frequency equal to or higher than the engagement frequency in the acceleration signal, And a harmonic main body corresponding to an integral multiple of the engaging frequency And a control unit configured to determine that the reduction gear is in an axial failure state when the amplitude of the vehicle is equal to or greater than a fourth reference value and inform the driver of the vehicle of the abnormal state when the reduction gear is in the abnormal state, Motor control system.

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