CN101131397A - Wheel velocity and acceleration detecting system and detecting method thereof - Google Patents
Wheel velocity and acceleration detecting system and detecting method thereof Download PDFInfo
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- CN101131397A CN101131397A CNA2006101256400A CN200610125640A CN101131397A CN 101131397 A CN101131397 A CN 101131397A CN A2006101256400 A CNA2006101256400 A CN A2006101256400A CN 200610125640 A CN200610125640 A CN 200610125640A CN 101131397 A CN101131397 A CN 101131397A
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Abstract
The invention discloses a system to detect the wheel speed and/or acceleration. The system includes a sensor connected to the wheel and processor. The sensor includes a circuit (such as Wheatstone bridge circuit) with many resistances (4). The every resistance includes a huge reluctance element and resistance value which at least part can change along to the change of external magnetic field intensity. At least part of the sensor can generate the signal according to the resistance value. The processor can compute the wheel speed and/or acceleration according to the signal. The invention also discloses the method to detect the wheel speed and/or acceleration by the system. The invention can detect the speed/acceleration of wheel speed and control the motor running state and optimize the speed.
Description
Technical field
The present invention relates to a kind of magnetic transducing device, relate in particular to a kind of system and method thereof of using magnetic sensor units to come detecting wheel speed and/or acceleration.
Background technology
Use many kinds of technology in the speed sensing device and come the rotating speed of exploring block.For example in various vehicles, just (ant-lock braking systems, ABS) common cooperation comes detecting wheel speed to speed sensing device with anti-block braking system of car.The speed sensing device that U.S. Patent application discloses a kind of special use the 10/847th, No. 838 please be incorporated the full content of this patented claim as reference of the present invention into.
Orthodox car has been installed the magnetic code wheel, and the outside surface of this kind wheel has magnetized ferrite.Particularly, this magnetized ferrite is contained in the laminate, and has alternately the South Pole and the arctic, laminate along the coding wheel circumference around.Be provided with link in the coding wheel, it protrudes out the magnetropism sensing device from wheel surface.Along with the rotation of wheel, the magnetic transducing device can be surveyed the situation of change of the magnetic field intensity of alternating poles, the rotating speed that can calculate the coding wheel according to this situation of change and this magnetic field that replaces of sensing device output.Can use the peak value and the relation between the number of magnetic poles that replaces in coding one week of wheel of for example sensing device output in this calculating.
A kind of magnetic transducing device that is used for speed of detection comprises a hall effect sensor (Hall effecttransducer).When magnetic field existed, this sensor produced transverse current; When giving these sensor two ends, will produce longitudinal current for direct current.Under the situation of magnetic field existence, the lateral voltage of hall effect sensor induced inside can be measured by second pair of electrode of vertical first pair of electrode.Along with the rotation of coding wheel, the electromotive force of sensor surface produces sinewave output.
Figure 1A is the synoptic diagram of a typical automotive, and this automobile has the speed pickup and the scrambler of cooperating with it.Figure 1B is the part enlarged diagram of coding wheel, has shown the magnetic field that results from the coding wheel.Coding wheel 10 is connected with the main drive shaft 20 that drive wheels 22 is rotated.One anti-lock braking system(ABS) 14 is positioned on the coding wheel 10, and it comprises a magnetic sensor 16 and an automobile Control Component 18.During 10 magnetization of coding wheel, can around it, produce a plurality of south magnetic poles that replace and north magnetic pole.When coding wheel 10 rotated, magnetic field changed, and magnetic sensor 16 can detect this variation and induce electromotive force.Automobile Control Component 18 comes computing velocity and this rate signal is passed to anti-lock braking system(ABS) 14 according to induced potential.
Yet there are some defectives in this technology.For example, produce and can produce the south magnetic pole of alternation around the wheel and the system of north magnetic pole is a difficulty, expensive at coding, and this system very complex.And, for the running quality of Control of Automobile, must survey the velocity of rotation and the acceleration of automobile, and prior art can only be surveyed the speed of automobile.
Therefore, be necessary to provide a kind of improved system to overcome the deficiencies in the prior art.
Summary of the invention
The object of the present invention is to provide the system of a kind of detecting wheel speed and/or acceleration, can survey the speed/acceleration of motion wheel easily, control the running status of system automobile effectively, help control and optimize the speed of a motor vehicle.
Another object of the present invention is to provide the method for a kind of detecting wheel speed and/or acceleration, can predict the speed/acceleration of motion wheel easily, control the running status of system automobile effectively, help control and optimize the speed of a motor vehicle.
For achieving the above object, the invention provides the system of a kind of detecting wheel speed and/or acceleration, be connected to the sensor on the described wheel, described sensor comprises that one has the circuit of some resistance, described each resistance have one to small part with respect to the change of magnetic field strength of external magnetic field and variable resistance value, described sensor to small part produces signal according to the resistance of described resistance; And to small part according to the speed of described calculated signals swivel wheel and/or the processor of acceleration.
In the system embodiment of detecting wheel speed of the present invention and/or acceleration, described sensor is according to the Wheatstone bridge circuit principles of construction.Four resistance of this bridge diagram include a giant magnetoresistance (GMR) element, and the resistance of described giant magnetoresistance element changes according to the variation of the magnetic field intensity of external magnetic field.Two giant magnetoresistance elements that are arranged in each half-bridge all are in different magnetic field, and therefore when wheel, the output terminal of electric bridge can produce differential voltage, so the different magnitude of voltage of sensor output.
The invention provides the method for a kind of detecting wheel speed and/or acceleration, this method comprises the steps: that on wheel configuration one has the sensor of the circuit of some resistance; Near small part is the variation of resistance according to the change transitions with respect to the magnetic field intensity of external magnetic field of the element in described resistance reflection; Produce signal according to described resistance; And to small part according to described calculated signals rotating-wheel speed and/or acceleration.
In the method embodiment of detecting wheel speed of the present invention and/or acceleration, described sensor is according to the Wheatstone bridge circuit principles of construction.Four resistance of Wheatstone bridge circuit are made by giant magnetoresistance (GMR) element, and giant magnetoresistance element changes resistance according to the variation of the magnetic field intensity of external magnetic field.Two giant magnetoresistance elements that are arranged in each half-bridge kind all are in different magnetic field, and therefore when wheel, the output terminal of electric bridge can produce differential voltage, so the different magnitude of voltage of sensor output.
In one embodiment of this invention, described Wheatstone bridge circuit comprises four resistance.In another embodiment of the present invention, described each giant magnetoresistance element comprise at least by ferromagnetic layer and non-magnetosphere constitute two-layer at least.In further embodiment of this invention, described external magnetic field is the terrestrial magnetic field.
In yet another embodiment of the invention, described signal is the waveform with period T, and the distance at the described rotating-wheel of described sensor distance center is R.Described processor calculates the speed of described rotating-wheel according to formula speed=2 π R/T.In the present invention again among another embodiment, described waveform is one can be reflected in the waveform of one hour velocity variations Δ u in the section Δ t, and described processor calculates the acceleration of described rotating-wheel according to formula acceleration=Δ u/ Δ t.
In the embodiment of the invention.Described sensor has adopted anisotropic magnetoresistance (AMR), has worn and satisfy formula magneto-resistor (TMR) or Hall effect element.This sensor uses the terrestrial magnetic field, and does not need other magnet, magnetic element or magnetizer.The structure of this simplification can reduce manufacturing cost.In addition, this size sensor is little, can be used to survey the speed and/or the acceleration of variety classes object.
Compared with prior art, the present invention has overcome the defective that prior art can only be surveyed car speed, can predict the speed/acceleration of motion wheel easily, controls the running status of system automobile effectively, helps control and optimizes the speed of a motor vehicle.
By describing the present invention ground technology contents, structural attitude in detail, being reached purpose and effect, once in conjunction with the embodiments also conjunction with figs. illustrated in detail.
Description of drawings
Figure 1A has the automotive speed sensor and the synoptic diagram of the orthodox car of the scrambler of cooperating (encoder) with it.
Figure 1B is the part enlarged diagram of the coding wheel (encoder wheel) among Fig. 1, has shown the magnetic field of coding wheel.
Fig. 2 A is the synoptic diagram of the anti-block braking system of car of one embodiment of the invention.
Fig. 2 B is the circuit diagram with Wheatstone bridge circuit (Wheatstone bridgecircuit) cooperating of the present invention's one example magnetic transducing device.
Fig. 2 C is the block diagram of the sensing device of one embodiment of the invention.
Fig. 2 D-2E has showed the relation between magnetic field intensity, angle and the resistance.
Fig. 3 is the simplification simulation drawing of terrestrial magnetic field.
Fig. 4 is the synoptic diagram of the wheel with magnetic transducing device of one embodiment of the invention.
Fig. 5 is the curve map of the present invention's one example sensing device output voltage and time relationship, detail display one embodiment of the invention calculate the method for wheel velocity.
Fig. 6 is the curve map of the present invention's one example sensing device output voltage and time relationship, detail display one embodiment of the invention calculate the method for wheel acceleration.
Fig. 7 is the process flow diagram that calculates the method for the speed of swivel wheel and acceleration.
Embodiment
Below exemplary embodiment a kind of sensing device will be provided, this device comprises a printed circuit-board assembly (PCBA), a Wheatstone bridge circuit, a terrestrial magnetic field detector and a processor.In four resistance of Wheatstone bridge circuit, each resistance is made by giant magnetoresistance (GMR) element, each huge magnetic set of pieces is a layer structure, and this layer structure comprises an at least one ferromagnetic layer (as fixed bed (pin layer)) and a non-magnetosphere (as free layer (free layer)).When the external magnetic field changes, free layer or non-magnetosphere will rotate along ferromagnetic layer or fixed bed, and then cause ferromagnetic layer or fixed bed resistance variations.
Wheatstone bridge is generally measured unknown resistance by the method for balanced bridge two arms.And the Wheatstone bridge in the embodiment of the invention is used so that the differential wave output power of giant magnetoresistance element increases doubly.Shown in Fig. 2 B, the giant magnetoresistance element of a half-bridge has identical pin top direction (pin direction) in the Wheatstone bridge circuit, and the giant magnetoresistance element of another half-bridge has opposite pin top direction.Therefore, the magnetic field that every half-bridge produces can induce maximum differential voltage at the electric bridge output terminal, thereby has improved the measuring accuracy of sensing device potentially.
Magnetic resistance generally is meant when certain material is applied in the external magnetic field, the performance that its resistance increases or reduces.A kind of special magnetic resistance, giant magnetoresistance effect are exactly quantum mechanical effects, for example in the membrane structure that is made of alternate iron magnetosphere and no magnetic metal level this kind effect can take place.Giant magnetoresistance shows as resistance and will obviously reduce, promptly when because the weak antiferromagnetic coupling of the interlayer resistance when causing the magnetization vector antiparallel of adjacent ferromagnetic is a higher value (a null field state), is reduced to owing to apply the external magnetic field and causes that the resistance the when magnetization vector of adjacent ferromagnetic is parallel is a smaller value.Electronic spin direction or antiparallel parallel with the external magnetic field in the no magnetic metal, therefore, when the magnetization vector of adjacent ferromagnetic was parallel, spinning electron can be subjected to less magnetic scattering.Can use multilayer giant magnetoresistance, spin valve giant magnetoresistance and/or granular giant magnetoresistance in certain embodiments.And use anisotropic magnetoresistance (AMR) in certain embodiments, wear then formula magneto-resistor (TMR) or hall effect sensor replaces above-mentioned giant magneto-resistance sensor.
Sensing device is arranged in wheel.When wheel rotated, sensor detected the variable quantity with respect to the terrestrial magnetic field, and this variable quantity to small part can be the variation of the angle of terrestrial magnetic field and magnetic transducing device fixed bed direction.In specific embodiment, why this effect can take place, and is that the giant magnetoresistance element of another half-bridge has opposite pin top direction because the giant magnetoresistance element of a half-bridge has identical pin top direction (pin direction) in the Wheatstone bridge circuit.Therefore, the magnetic field of every half-bridge generation can produce maximum differential voltage at output terminal.Processor is used to calculate and optionally show the speed and/or the acceleration of wheel.
With reference now to accompanying drawing, describe embodiments of the invention, similar Reference numeral is represented similar elements in the accompanying drawing.Fig. 2 A is the synoptic diagram of the anti-block braking system of car of one embodiment of the invention.Anti-block braking system of car shown in the figure comprises a magnetic transducing device 200, and this magnetic transducing device 200 can be collected data from coding wheel 203.One Control Component 202 gives sensing device 200 power supplies.In addition, Control Component 202 is detectable and/or calculate the differential voltage that is produced by the Wheatstone bridge circuit in the sensing device 200.
Circuit shown in Fig. 2 B is used to cooperate the Wheatstone bridge circuit work of magnetic sensor device.Wheatstone bridge circuit has four giant magnetoresistance sensing element A1, A2, A3 and A4.Preferably, the giant magnetoresistance sensing element of each half-bridge has identical pin top direction, and the pin top direction of the giant magnetoresistance sensing element of two different half-bridges is opposite.For example, shown in pd1 among the figure and pd2, giant magnetoresistance sensing element A1 has identical pin top direction with A2, and A3 has identical pin top direction with A4, and A1, A2 have opposite pin top direction with A3, A4.Such design can make sensing device keep maximum differential voltage output.
Add between giant magnetoresistance element A1 and the A4 that DC voltage Vcc powers to system.Meet a ground wire GND between giant magnetoresistance element A2 and the A3.One of differential voltage output terminates between A1, A3, and the other end is connected between A2, A4.Certainly other similar structure (for example changing voltage input end, earth point and differential voltage reading end etc.) is feasible, also is expected.
The block diagram of the sensing device 200 of Fig. 2 C one embodiment of the invention.When wheel 203 rotates, in Wheatstone bridge circuit, induce differential voltage (as sine wave), sensor 210 is surveyed changes of magnetic field.The signal that sends from sensor 210 passes to processor 212.Processor 212 calculates wheel velocity and/or acceleration, and transmission result of calculation is stored into storer 216 to velocity indicator 214 and/or the result.
Fig. 2 D and 2E have showed the relation between magnetic field intensity, angle and the resistance.When magnetic direction changed along with giant magnetoresistance pin top direction, the variable quantity of the variable quantity of its angle and giant magnetoresistance element resistance was proportional.This variation Wheatstone bridge two ends that coexist apply voltage and have same effect.Because the pin top direction of the giant magnetoresistance element of two half-bridges is opposite, therefore when wheel rotates, can induce an electromotive force (as sinusoidal voltage) at the differential voltage output terminal.For example, shown in Fig. 2 D, along with angle θ increases, magnetic field intensity also increases (for explanation, be with amperes per meter, promptly H measures) herein.Correspondingly, shown in Fig. 2 E, the variation of angle θ is corresponding with the variation of the rate of change (Δ R/R) of resistance value or resistance value.
Fig. 3 is the simplification simulation drawing of terrestrial magnetic field, has shown geographical south poles and electromagnetism south poles.As can be seen from the figure, differ about 11.5 ° between the south geographical pole and the electromagnetism South Pole, the earth 301 is around the axis of rotation rotation shown in the curved arrow around the north geographic pole among the figure.The earth 301 has magnetic field 303, and this magnetic field 303 induces the magnetic line of force 304 (also claim earth magnetosphere, it extends to about 70000 kms of space), and this magnetic line of force 304 originates in the arctic and ends at the South Pole.When wheel rotated in the terrestrial magnetic field, sensing device can be surveyed changes of magnetic field and produce output signal thus.
Fig. 4 has showed how the magnetic transducing device of one embodiment of the invention works.Fig. 4 especially has the synoptic diagram of the wheel 203 of magnetic transducing device 200.When wheel 203 during at position A, the magnetic field of the earth direction is vertical with the direction of fixed bed and free layer, and at this moment, sensing device produces a maximum output, the peak-peak corresponding (following detailed description) of this output and sine wave.When wheel 203 when the A point begins to rotate, have an angle 0 between the direction of magnetic direction and fixing/free layer because more and more weak the action of a magnetic field, this wheel can produce less output.When wheel 203 when position C rotates, the influence in magnetic field slowly weakens, when wheel arrived C point, because its effective magnetic field is zero, therefore exporting also was 0.When wheel 203 when the C point is rotated further, effective magnetic field increases thereupon, and reaches maximum output valve during A ' position once more in arriving as figure.In like manner, when wheel 203 from position A ' in a clockwise direction during home position A, sensing device 200 is with sinewave output.It should be noted that above position is self-defining, with convenient explanation, sensing device also arbitrarily sampling rate produce signal (result of higher sampling rate generation is more accurate).For example, can per 5 milliseconds of (ms) once sampling.Sensor on the wheel is provided with the position can be changed, and it exports also corresponding change (as phase shift).
Fig. 5 is the present invention's one sensing device output voltage and time relation curve, detail display the present invention calculate the method for wheel velocity.As previously mentioned, when sensing device rotated along with wheel, it produced sinusoidal output.On the sinusoidal output line from figure, sine-shaped as can be seen period T.After sensing device was installed, the radius R of sensing device (with respect to wheel) was a known number.This moment, wheel velocity equaled 2 π R/T, and it is that processor by sensing device calculates.Processor can also carry out error detection occurs.
Fig. 6 is the present invention's one sensing device output voltage and time relation curve, detail display the present invention calculate the method for wheel acceleration.As previously mentioned, when sensing device rotated along with wheel, it produced sinusoidal output.On the sinusoidal output line from figure, sine-shaped as can be seen period T.Same processor calculates the velocity variable Δ u in the short time interval Δ t.This brief acceleration equals Δ u divided by Δ t.Certainly, processor can also carry out error detection occurs.
Fig. 7 is a process flow diagram of surveying the method for the speed of swivel wheel and acceleration.Step S70 installs sensing device on swivel wheel, this sensing device contains a circuit that comprises giant magnetoresistance element resistance.Step S72 is according to the change of magnetic field strength with respect to the external magnetic field of giant magnetoresistance element reflection, the variation of the resistance that has a resistance.Step S74 according to resistance, produces signal.Step S76, using formula calculates wheel velocity and/or acceleration.In concrete enforcement, anisotropic magnetoresistance, wear then the formula magneto-resistor or the Hall effect sensing element all can be used for speed of detection and/or acceleration.
Although the foregoing description has described the device and/or the method for carrying out speed of detection and/or acceleration in having the automobile of anti-lock braking system(ABS) in detail, this technology also can be used for the motor vehicle (as automobile, bus, motorcycle, bicycle etc.) of any model any kind of.For example, it can be used for measuring speed and/or acceleration, thus for the driver provide additional, optionally with reference to be better controlled.Equally, it also can be used in the driver assistance system, can change the speed of a motor vehicle effectively.In addition, the present invention can be used for vehicle field in addition.The present invention can be used for any parts with wheel, for example a hard disk.
What more than disclose only is preferred embodiment of the present invention, can not limit the present invention's interest field certainly thus.Therefore the scope that the present invention is contained is still stated in the equal variation of doing according to patent claim of the present invention.
Claims (14)
1. the system of detecting wheel speed and/or acceleration comprises:
Be connected to the sensor on the described wheel, described sensor comprises that one has the circuit of some resistance, described each resistance have one to small part with respect to the change of magnetic field strength of external magnetic field and variable resistance value, described sensor to small part produces signal according to the resistance of described resistance; And
To small part according to the speed of described calculated signals swivel wheel and/or the processor of acceleration.
2. the system of detecting wheel speed as claimed in claim 1 and/or acceleration is characterized in that: described each resistance comprises at least one giant magnetoresistance element.
3. the system of detecting wheel speed as claimed in claim 1 and/or acceleration is characterized in that: described circuit is a Wheatstone bridge circuit.
4. the system of detecting wheel speed as claimed in claim 2 and/or acceleration is characterized in that: described each giant magnetoresistance element comprises and comprises the two-layer at least of ferromagnetic layer and non-magnetosphere at least.
5. the system of detecting wheel speed as claimed in claim 1 and/or acceleration is characterized in that: described each resistance comprises the anisotropic magnetoresistance element, wears at least one that satisfy among formula magnetoresistive element or the Hall effect element three.
6. the system of detecting wheel speed as claimed in claim 1 and/or acceleration is characterized in that: described external magnetic field is the terrestrial magnetic field.
7. the system of detecting wheel speed as claimed in claim 1 and/or acceleration, it is characterized in that: described signal is the waveform with period T, the distance at the described rotating-wheel of described sensor distance center is R, and described processor calculates the speed of described rotating-wheel according to formula 2 π R/T.
8. the system of detecting wheel speed as claimed in claim 1 and/or acceleration, it is characterized in that: described signal is a waveform that can be reflected in a hour velocity variations Δ u in the section Δ t, and described processor calculates the acceleration of described rotating-wheel according to formula Δ u/ Δ t.
9. the method for detecting wheel speed and/or acceleration is characterized in that comprising the steps:
Configuration one has the sensor of the circuit of some resistance on wheel;
Near small part is the variation of resistance according to the change transitions with respect to the magnetic field intensity of external magnetic field of the element in described resistance reflection;
Produce signal according to described resistance; And
To small part according to described calculated signals rotating-wheel speed and/or acceleration.
10. detecting wheel speed as claimed in claim 9 and/or acceleration method is characterized in that: described each resistance comprises the anisotropic magnetoresistance element, wears at least one that satisfy among formula magnetoresistive element or the Hall effect element three.
11. the method for detecting wheel speed as claimed in claim 9 and/or acceleration is characterized in that: described circuit is a Wheatstone bridge circuit.
12. the method for detecting wheel speed as claimed in claim 9 and/or acceleration is characterized in that: described external magnetic field is the terrestrial magnetic field.
13. the method for detecting wheel speed as claimed in claim 9 and/or acceleration, it is characterized in that: described signal is the waveform with period T, the distance at the described rotating-wheel of described sensor distance center is R, and described processor calculates the speed of described rotating-wheel according to formula 2 π R/T.
14. the method for detecting wheel speed as claimed in claim 9 and/or acceleration, it is characterized in that: described signal is one can be reflected in the waveform of the velocity variations Δ u in hour section Δ t, and described processor calculates the acceleration of described rotating-wheel according to formula Δ u/ Δ t.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2006101256400A CN101131397A (en) | 2006-08-23 | 2006-08-23 | Wheel velocity and acceleration detecting system and detecting method thereof |
| JP2007215563A JP2008051815A (en) | 2006-08-23 | 2007-08-22 | Detection system of velocity/acceleration of rotation wheel, and calculating method of velocity/acceleration of rotation wheel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2006101256400A CN101131397A (en) | 2006-08-23 | 2006-08-23 | Wheel velocity and acceleration detecting system and detecting method thereof |
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| Publication Number | Publication Date |
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| CN101131397A true CN101131397A (en) | 2008-02-27 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2006101256400A Pending CN101131397A (en) | 2006-08-23 | 2006-08-23 | Wheel velocity and acceleration detecting system and detecting method thereof |
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| JP (1) | JP2008051815A (en) |
| CN (1) | CN101131397A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105699683A (en) * | 2016-03-29 | 2016-06-22 | 杭州和利时自动化有限公司 | Steam turbine rotation speed measurement method and steam turbine rotation speed measurement system |
| CN112208543A (en) * | 2020-09-25 | 2021-01-12 | 上海拿森汽车电子有限公司 | Wheel speed estimation method and device and vehicle |
| CN112945292A (en) * | 2019-12-11 | 2021-06-11 | 上海磁宇信息科技有限公司 | Gear position/speed sensor |
| CN113295881A (en) * | 2021-06-17 | 2021-08-24 | 工业互联网创新中心（上海）有限公司 | High-precision wire feeding speed measuring device and method for general industrial welding machine |
-
2006
- 2006-08-23 CN CNA2006101256400A patent/CN101131397A/en active Pending
-
2007
- 2007-08-22 JP JP2007215563A patent/JP2008051815A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105699683A (en) * | 2016-03-29 | 2016-06-22 | 杭州和利时自动化有限公司 | Steam turbine rotation speed measurement method and steam turbine rotation speed measurement system |
| CN112945292A (en) * | 2019-12-11 | 2021-06-11 | 上海磁宇信息科技有限公司 | Gear position/speed sensor |
| CN112208543A (en) * | 2020-09-25 | 2021-01-12 | 上海拿森汽车电子有限公司 | Wheel speed estimation method and device and vehicle |
| CN112208543B (en) * | 2020-09-25 | 2021-08-06 | 上海拿森汽车电子有限公司 | Wheel speed estimation method and device and vehicle |
| CN113295881A (en) * | 2021-06-17 | 2021-08-24 | 工业互联网创新中心（上海）有限公司 | High-precision wire feeding speed measuring device and method for general industrial welding machine |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2008051815A (en) | 2008-03-06 |
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Open date: 20080227 |