CN109895841B - Method for evaluating health state of belt transmission device in electric power steering system - Google Patents
Method for evaluating health state of belt transmission device in electric power steering system Download PDFInfo
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- CN109895841B CN109895841B CN201711284264.4A CN201711284264A CN109895841B CN 109895841 B CN109895841 B CN 109895841B CN 201711284264 A CN201711284264 A CN 201711284264A CN 109895841 B CN109895841 B CN 109895841B
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Abstract
The invention provides a method for evaluating the health state of a belt transmission device in an electric power steering system. The health state of the belt transmission device is judged by detecting the sliding tooth phenomenon and the frequency of the sliding tooth phenomenon generated in the electric power steering system and even considering the output force of the motor. Therefore, the user can really know the health state of the belt transmission device of the electric power steering system.
Description
Technical Field
The invention relates to an electric power steering system, in particular to a method for evaluating the health state of a belt transmission device in the electric power steering system.
Background
Along with the development of automobile science and technology and the development of environmental protection consciousness, the automobile uses electric power steering system to replace traditional hydraulic power steering system gradually, and its reason lies in:
1. in the conventional hydraulic power-assisted steering system, when the engine runs, the hydraulic pump is always in a working state to consume part of power of the engine, so that the oil consumption of the whole engine is increased. The backsight electric power-assisted steering system takes a battery as an energy source, is independent of the operation of an engine without increasing the power consumption of the engine, and has higher working efficiency than a hydraulic power-assisted steering system so as to save fuel consumption.
2. The electric power steering system can be integrated on the same device, and convenience in assembly and maintenance is improved. The hydraulic power steering is to arrange components with different functions at different places, and generates a steering auxiliary function through a pipeline arrangement.
3. The electric power steering system has no hydraulic oil replacement problem of a hydraulic power steering system, and is environment-friendly.
4. The electric power steering system can adjust the auxiliary force according to different driving conditions through software control to improve the stability and comfort of automobile operation. The hydraulic power steering system maintains a fixed auxiliary force and cannot change the auxiliary force according to the driving condition.
For the electric power steering system, the electric power steering system can be divided into a Column power-assisted electric power steering system (Column-Type EPS), a Pinion power-assisted electric power steering system (Pinion-Type EPS) and a Rack power-assisted electric power steering system (Rack-Type EPS).
For a Rack-assisted electric power steering system (Rack-Type EPS), the operation mode is that after a user rotates a steering wheel, a steering column driving gear is meshed with a Rack part of a steering frame to drive the steering frame to move, meanwhile, a torque sensor arranged on the steering column transmits information to an electronic control unit, the electronic control unit controls a motor to drive a driving wheel and then drive a belt, the belt drives a driven wheel sleeved outside a nut to rotate and drive the nut to rotate, and the nut drives a screw rod part on the steering frame to move, so that the effect of providing steering auxiliary force for the user is achieved.
In the electric power steering system, when the belt is selected, the maximum torque upper limit that the belt can bear under different tensions can be roughly known through belt parameters and an installation mode, but the tension of the belt can be reduced due to looseness, deformation or aging of a mechanism and the belt after long-term use, so that the bearable torque upper limit is reduced, and further, the rotation among the driving wheel, the belt or the driven wheel is inconsistent, and the phenomenon of gear slippage occurs. Therefore, the sliding tooth phenomenon represents the aging of the belt transmission device, which will cause the electric power steering system to generate insufficient auxiliary force, or when the belt is broken, the user suddenly loses the auxiliary force when steering, and then driving danger occurs. Therefore, it is particularly important to evaluate the tooth slipping phenomenon to enable a user to know the health status of the belt transmission device of the electric power steering system.
For the State of Health (SOH) indicator of an electric power steering system, US8634986a1 has proposed a main technical content including the following steps: and calculating the self-aligning moment of the first tire through the dynamic model. And obtaining the self-aligning moment of the second tire through state estimation. The difference between the self-aligning torque of the first tire and the self-aligning torque of the second tire is calculated. A health status indicator ranging from 0 to 1 is calculated by continuously observing this difference. And determining a control action based on the health status indicator. The health index obtained by the method comprises the state of the whole electric auxiliary steering system, and the health state of each part cannot be discussed independently, so that the health state of the driving belt cannot be known independently to avoid the influence of sudden breakage of the belt on a driver in advance.
Further, WO2017061257 a1 proposes a method of coping with a failure of an angle sensor, and also provides a system abnormality diagnosis. However, only sudden abnormal conditions can be detected, and the health status of the electric power steering system cannot be known.
Disclosure of Invention
The present invention provides a method for evaluating a health status of a belt transmission in an electric power steering system, which allows a user to know the health status of the belt transmission in the electric power steering system through evaluation of a tooth slipping phenomenon, thereby reducing a risk of failure of the electric power steering system.
Therefore, according to the present invention, a method for assessing the health of a belt drive in an electric power steering system is provided, which is applied to an electric power steering system comprising a steering mechanism having a housing and a bogie, the housing having a first opening and a second opening; the bogie is arranged in the shell and respectively penetrates out of the first opening and the second opening, and the bogie is provided with a rack part and a screw rod part; a gear fixedly connected to a steering column and engaging the rack portion; a nut screwed with the screw part in the housing; the motor is fixedly connected with the shell and provided with at least one rotor and an output shaft, and the rotor drives the output shaft to rotate; a driving wheel is fixedly connected with the output shaft; a driven wheel is sleeved on the nut; a belt, which is sleeved on the driving wheel and the driven wheel; the method for evaluating the health state of the belt transmission device in the electric power steering system further comprises the following steps: information measurement: measuring the rotation of the steering column at each operating time point using a first sensor to generate a first measurement information; measuring the rotation of the rotor at each time point using a second sensor, generating a second measurement information; and (3) information interpretation: reading the first measurement information and the second measurement information using an Electronic Control Unit (ECU); the electronic control unit stores a database in advance, and the database stores a rotation relation and judgment bases of the rotor corresponding to the steering columns; judging the sliding tooth state: the electronic control unit generates comparison information by using the first measurement information/the second measurement information and matching with the rotation relation in the database; the electronic control unit compares the second measurement information/the first measurement information with the comparison information, and if the difference between the two is less than a threshold value, the electronic control unit judges that the measurement is normal; if the difference between the two exceeds the threshold value, the sliding tooth phenomenon is judged to be generated.
Therefore, when the sliding tooth phenomenon occurs, the health state of the belt transmission device of the electric power steering system is reduced, a user can be reminded in advance, and the risk of failure of the electric power steering system is reduced.
Wherein, the first measurement information and the second measurement information are one of rotation angle, angular velocity and angular acceleration or a combination thereof.
In addition, in step c), after determining that the tooth-slipping phenomenon occurs, the electronic control unit generates a warning message, which is used to send a warning to warn the user.
It is worth mentioning that there is also a step d) of health status determination: the electronic control unit records the time point of occurrence of the sliding tooth phenomenon, and judges that in a preset time period, if the frequency of occurrence of the sliding tooth phenomenon is less than a threshold frequency pre-stored in the electronic control unit, an alert state is judged; and if the occurrence frequency of the sliding tooth phenomenon is greater than the threshold frequency, judging the dangerous state. Likewise, in step d), after determining the dangerous condition, the electronic control unit generates a warning message, which is used to warn the user by issuing a warning.
Or in step d), the driver's output is also measured using a torque sensor located on the steering column or the motor output is also evaluated using a current sensor, outputting an output signal to the electronic control unit; setting a high output condition, and defining the high output state when the output value represented by the output signal is greater than the high output condition; if the sliding tooth phenomenon does not occur, defining the sliding tooth phenomenon as a normal state; if the sliding tooth phenomenon occurs in the non-high-force state, the state is defined as a dangerous state; if the tooth sliding phenomenon occurs in the high output state but the occurrence frequency is less than the threshold frequency, judging the alert state; and if the tooth slipping phenomenon occurs in the high-output state and the occurrence frequency is greater than the threshold frequency, determining that the state is a dangerous state. Therefore, the use condition can be more finely divided and is more close to the requirement of a user.
Drawings
Fig. 1 is a perspective view of a first preferred embodiment of the present invention, showing an electric power steering system.
FIG. 2 is a cross-sectional view of the first preferred embodiment of the present invention, showing an electric power steering system.
Fig. 3 is a partial perspective view of the first preferred embodiment of the present invention, showing an electric power steering system.
FIG. 4 is a system diagram of a first preferred embodiment of the present invention, showing an electric power steering system.
FIG. 5 is a block flow diagram of a first preferred embodiment of the present invention, showing a method of assessing the health of a belt drive in an electric power steering system.
FIG. 6 is a flow chart illustrating a method for assessing the health of a belt drive in an electric power steering system according to a second preferred embodiment of the present invention.
FIG. 7 is a flow chart of another aspect of the second preferred embodiment of the present invention, wherein the determination condition of the high-out state is increased.
[ notation ] to show
10 electric power steering system 11 steering mechanism (steering mechanism)
111 casing 111a first opening
111b second opening 112 bogie (steering rack)
112a Rack portion (linked portion) 112b screw portion (swept portion)
12 Gear (pinion) 121 steering column (steering column)
13 nut 14 motor
142 output shaft 143 drive wheel
144 passive wheel 145 belt
15 first sensor 16 second sensor
17 electronic control unit 18 torque sensor
19 Current sensor 21 track rod (tie rod)
D database
Detailed Description
For a detailed description of the technical features of the present invention, reference will now be made to the following preferred embodiments, which are illustrated in the accompanying drawings, wherein:
referring to fig. 1 to 3, a method for evaluating the health of a belt drive in an electric power steering system 10, which includes a steering mechanism 11, a gear 12, a nut 13 and a motor 14, is provided according to a first preferred embodiment of the present invention.
The steering mechanism 11 has a housing 111 and a steering rack 112, the housing 111 having a first opening 111a and a second opening 111 b. The bogie 112 is disposed in the housing 111 and respectively penetrates the first opening 111a and the second opening 111b, and the bogie 112 has a rack portion 112a and a screw portion 112 b. The tie rods 21 connected to the wheels are connected to the bogie 112, respectively, and driven by the bogie 112.
The gear 12 is fixed to a steering column 121 and engages with the rack portion 112 a. The pinion 12 is rotated by the column 121 and drives the rack portion 112a to move the bogie 112.
The nut 13 is screwed to the screw portion 112b in the housing 111. When the nut 13 is rotated, the screw portion 112b can be driven to move.
The motor 14 is fixed to the housing 111, and the motor 14 has at least one rotor (this part is conventional and not shown) and an output shaft 142. A driving wheel 143 fixedly connected with the output shaft 142. A driven wheel 144 is fitted over the nut 13. And a belt 145 sleeved on the driving wheel 143 and the driven wheel 144. When the motor 14 is controlled to rotate the rotor to drive the output shaft 142, the driving wheel 143 drives the belt 145 to move, and the driven wheel 144 transmits the power to the nut 13, so as to drive the screw portion 112b to move.
Referring to fig. 1 to 5, the method for evaluating the health status of the belt transmission device in the electric power steering system further includes the following steps:
a) information measurement: the rotation of the steering column 121 at each operating point in time is measured using a first sensor 15, resulting in a first measurement information. A second sensor 16 is used to measure the rotation of the rotor at each point in time, resulting in a second measurement.
b) And (3) information interpretation: the first measurement information and the second measurement information are read using an Electronic Control Unit (ECU) 17. The electronic control unit 17 stores in advance a database D that stores a rotational relationship of the rotor with respect to the steering column 121 and each judgment basis. This rotational relationship is a proportional relationship of the rotation between the rotor and the steering column 121 in the case where the electric power steering system is healthy.
For example, as shown in FIG. 4, when the driving wheel 143 has N teethmAngle of rotation theta of rotormDriven wheel 144 having N teethbsThe rotation angle theta of the nut 13bsAt the time, since the transmission is performed by the belt 145, there is the following relationship
Nmθm＝Nbsθbs
In addition, the driven wheel 144 drives the nut 13 to rotate, and the number of turns of the nut 13 is in a fixed proportional relationship with the moving distance of the bogie 112; and, when the bogie 112 moves, the gear 12 is also driven by the rack portion 112a of the bogie 112Rotation of the gear 12 by an angle thetaswIn fixed proportional relation to the distance traveled by the bogie (linear-angle ratio), and the angle of rotation of the gear 12 is equal to the angle of rotation theta of the steering columnsw
Distance (mm) traveled by the bogie-theta-angle transmission ratio (mm/deg)sw(deg)
If the number of teeth of the driving wheel 143 is Nm48; passive wheel 144 with number of teeth Nbs148; when the nut 13 is turned 360 degrees, the bogie 112 moves 8 mm; when the gear 12 rotates 360 degrees, the bogie 112 moves 48.68mm, which is inferred from the above relationship
θbs(deg)＝0.3243θm(deg)
Nut rotation 0.3243 thetamAngle, bogie 112 and rack portion 112a move 7.207 x 10-3θm(mm)
θsw(deg)＝0.0533θm(deg) is the proportional relationship of rotation between the rotor and the steering column 121.
c) Judging the sliding tooth state: the electronic control unit 17 generates a comparison information by using the first measurement information/the second measurement information and matching the rotation relationship in the database D, in this embodiment, the second measurement information is taken as an example, and the first measurement information may also be used. The electronic control unit 17 compares the second measurement information/the first measurement information with the comparison information, and determines that the measurement is normal if the difference between the two is smaller than a threshold value, for example, ten percent; if the difference between the two exceeds the threshold value, the sliding tooth phenomenon is judged to be generated.
Therefore, when the gear slippage phenomenon occurs, the health state of the combination of the belt 145, the driving wheel 143 and the driven wheel 144 of the electric power steering system is reduced, a user can be reminded in advance, and the risk of failure of the electric power steering system is reduced.
It is worth mentioning that the first measurement information and the second measurement information are one of rotation angle, angular velocity, angular acceleration or a combination thereof.
In addition, in the embodiment, after determining that the tooth-slipping phenomenon occurs in step c), the electronic control unit 17 may generate a warning message to be used for sending a warning to warn the user, wherein the warning message is presented in a text, a sound or other manners.
Referring to fig. 1 to 4 and fig. 6, a method for evaluating the health status of a belt transmission device in an electric power steering system according to a second preferred embodiment of the present invention will be described. It differs from the first preferred embodiment in that there is a further step d) of health status determination: the electronic control unit 17 records the time point of occurrence of the sliding tooth phenomenon, and judges that in a preset time period, for example, 2 seconds, if the frequency of occurrence of the sliding tooth phenomenon is less than a threshold frequency (for example, 2 times/2 seconds) stored in the electronic control unit in advance, the warning state is determined; and if the occurrence frequency of the sliding tooth phenomenon is greater than the threshold frequency, judging the dangerous state. Likewise, in step d), after determining a dangerous condition, the electronic control unit 17 generates a warning message, which is used to warn the user by issuing a warning. It is worth mentioning that the result of the health status judgment reminds the driver in a way of displaying different light signals.
In addition, referring to fig. 7, optionally, in step d), a torque sensor 18(torque sensor) located on the steering column 121 is used to measure the driver's output or a current sensor 19 is used to estimate the output of the motor 14, and an output signal is output to the electronic control unit 17; setting a high output condition, and defining the high output state when the output value represented by the output signal is greater than the high output condition; if the sliding tooth phenomenon does not occur, defining the sliding tooth phenomenon as a normal state; if the sliding tooth phenomenon occurs in the non-high-force state, the state is defined as a dangerous state; if the tooth sliding phenomenon occurs in the high output state but the occurrence frequency is less than the threshold frequency, judging the alert state; and if the sliding tooth phenomenon occurs in the high-output state but the occurrence frequency is more than the threshold frequency, determining that the state is dangerous. Therefore, the use condition can be more finely divided and is more close to the requirement of a user.
Claims (4)
1. A method for evaluating the health of a belt drive in an electric power steering system, which is used in an electric power steering system, the electric power steering system comprises a steering mechanism having a housing and a bogie, the housing having a first opening and a second opening; the bogie is arranged in the shell and respectively penetrates out of the first opening and the second opening, and the bogie is provided with a rack part and a screw rod part; a gear fixedly connected to a steering column and engaging the rack portion; a nut screwed with the screw part in the housing; the motor is fixedly connected with the shell and provided with at least one rotor and an output shaft, and the rotor drives the output shaft to rotate; a driving wheel is fixedly connected with the output shaft; a driven wheel is sleeved on the nut; a belt, which is sleeved on the driving wheel and the driven wheel; the method for evaluating the health status of a belt drive in an electric power steering system is characterized by comprising the steps of:
a) information measurement: measuring the rotation of the steering column at each operating time point using a first sensor to generate a first measurement information; measuring the rotation of the rotor at each time point using a second sensor, generating a second measurement information;
b) and (3) information interpretation: reading the first measurement information and the second measurement information using an electronic control unit; the electronic control unit stores a database in advance, and the database stores a rotation relation and judgment bases of the rotor corresponding to the steering columns;
c) judging the sliding tooth state: the electronic control unit generates comparison information by using the first measurement information/the second measurement information and matching with the rotation relation in the database; the electronic control unit compares the second measurement information/the first measurement information with the comparison information, and if the difference between the two is less than a threshold value, the electronic control unit judges that the measurement is normal; if the difference between the two exceeds the threshold value, judging that the tooth sliding phenomenon is generated;
d) judging the health state: the electronic control unit records the time point of occurrence of the sliding tooth phenomenon, and judges that in a preset time period, if the frequency of occurrence of the sliding tooth phenomenon is less than a threshold frequency pre-stored in the electronic control unit, an alert state is judged; if the occurrence frequency of the sliding tooth phenomenon is greater than the threshold frequency, judging a dangerous state; in step d), the driver's output is also measured using a torque sensor located on the steering column or the motor output is also evaluated using a current sensor, outputting an output signal to the electronic control unit; setting a high output condition, and defining the high output state when the output value represented by the output signal is greater than the high output condition; if the sliding tooth phenomenon does not occur, defining the sliding tooth phenomenon as a normal state; if the sliding tooth phenomenon occurs in the non-high-force state, the state is defined as a dangerous state; if the tooth sliding phenomenon occurs in the high output state but the occurrence frequency is less than the threshold frequency, judging the alert state; and if the tooth slipping phenomenon occurs in the high-output state and the occurrence frequency is greater than the threshold frequency, determining that the state is a dangerous state.
2. The method of assessing the health of a belt drive in an electric power steering system according to claim 1, wherein: the first measurement information and the second measurement information are one of rotation angle, angular velocity, angular acceleration or a combination thereof.
3. The method of assessing the health of a belt drive in an electric power steering system according to claim 1, wherein: in step c), after determining that the tooth slipping phenomenon occurs, the electronic control unit generates a warning message to be used for sending out a warning.
4. The method of assessing the health of a belt drive in an electric power steering system according to claim 1, wherein: in step d), after determining the dangerous state, the electronic control unit generates a warning message, which is used to send out a warning.
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| CN201711284264.4A CN109895841B (en) | 2017-12-07 | 2017-12-07 | Method for evaluating health state of belt transmission device in electric power steering system |
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| CN201711284264.4A CN109895841B (en) | 2017-12-07 | 2017-12-07 | Method for evaluating health state of belt transmission device in electric power steering system |
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| CN109895841A CN109895841A (en) | 2019-06-18 |
| CN109895841B true CN109895841B (en) | 2020-09-04 |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112455532B (en) * | 2019-09-06 | 2022-02-08 | 上银科技股份有限公司 | Electric power steering system and control method |
| CN112644611B (en) * | 2020-12-02 | 2022-02-11 | 深圳市概念智慧科技有限公司 | Bicycle alarm method, device, equipment and storage medium |
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| JP2008105604A (en) * | 2006-10-26 | 2008-05-08 | Jtekt Corp | Electric power steering device |
| KR20090097625A (en) * | 2008-03-12 | 2009-09-16 | 주식회사 만도 | Rack-type electric power steering apparatus |
| JP2010101582A (en) * | 2008-10-24 | 2010-05-06 | Mitsubishi Heavy Ind Ltd | Refrigerator for transport |
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| CN103085857A (en) * | 2011-11-03 | 2013-05-08 | 万都株式会社 | Rack assist type steering apparatus and rack assist type electric power steering apparatus having the same |
| KR20130053896A (en) * | 2011-11-16 | 2013-05-24 | 현대자동차주식회사 | Method for sensing the belt's slip of r-mdps |
| CN107010101A (en) * | 2015-10-29 | 2017-08-04 | 株式会社万都 | Electric power-assisted steering apparatus |
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2017
- 2017-12-07 CN CN201711284264.4A patent/CN109895841B/en active Active
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|---|---|---|---|---|
| CN1784332A (en) * | 2003-05-06 | 2006-06-07 | 日本精工株式会社 | Belt speed reducer for electric power steering device and electric power steering device |
| JP2008105604A (en) * | 2006-10-26 | 2008-05-08 | Jtekt Corp | Electric power steering device |
| KR20090097625A (en) * | 2008-03-12 | 2009-09-16 | 주식회사 만도 | Rack-type electric power steering apparatus |
| JP2010101582A (en) * | 2008-10-24 | 2010-05-06 | Mitsubishi Heavy Ind Ltd | Refrigerator for transport |
| KR20110101437A (en) * | 2010-03-08 | 2011-09-16 | 유진테크주식회사 | Main shaft production method for electric power steering device |
| CN103085857A (en) * | 2011-11-03 | 2013-05-08 | 万都株式会社 | Rack assist type steering apparatus and rack assist type electric power steering apparatus having the same |
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