CN107554529B - Method and system for calculating vehicle speed of commercial vehicle - Google Patents
Method and system for calculating vehicle speed of commercial vehicle Download PDFInfo
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- CN107554529B CN107554529B CN201710734909.3A CN201710734909A CN107554529B CN 107554529 B CN107554529 B CN 107554529B CN 201710734909 A CN201710734909 A CN 201710734909A CN 107554529 B CN107554529 B CN 107554529B
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Abstract
The invention discloses a method and a system for calculating the speed of a commercial vehicle, wherein the method comprises the following steps: the distance between the center of the driving shaft and the ground is obtained and used as the radius of the tire, and the actual distance between the center of the driving shaft and the ground is used as the radius of the tire instead of a preset value, so that the accuracy of the radius of the tire is effectively improved; and then acquiring the rotation speed of the driving wheel per minute of the vehicle as the rotation speed of the tire, and acquiring the vehicle speed according to the radius of the tire and the rotation speed of the tire. The vehicle speed calculation method provided by the invention does not need to utilize parameters such as the traditional rear axle main reduction ratio, the transmission case odometer speed ratio and the like, so that various instruments do not need to be equipped for the commercial vehicle to adapt to the rear axle main reduction ratio and the transmission case odometer speed ratio corresponding to different load capacities, the complexity of production and assembly is greatly simplified, and the calculation result is more accurate because the radius of the tire and the rotating speed of the tire are actual values of the current vehicle.
Description
Technical Field
The invention relates to the technical field of automobiles, in particular to a method and a system for calculating the speed of a commercial vehicle.
Background
The vehicles are all provided with a speedometer for indicating the running speed of the vehicles, so that a driver can conveniently master the running speed and control the running speed.
The speedometer consists of a speedometer sensor arranged on a worm of a gearbox worm gear assembly of a wheel, a microcomputer processing system and a display, wherein a photoelectric pulse or magnetoelectric pulse signal sent by the speedometer sensor is processed by the microcomputer processing system in the speedometer, and then the speedometer displays the speed of the vehicle on the display screen. The microcomputer processing system needs to calculate the tire rotation speed per kilometer, wherein the tire rotation speed per kilometer is the rear axle main reduction ratio × 1000/(2 × pi × tire radius × gearbox odometer speed ratio), the rear axle main reduction ratio, the gearbox odometer speed ratio and the tire radius are preset fixed values, and then the vehicle speed is calculated according to the tire rotation speed per kilometer, for example, the vehicle speed is 5 seconds, the mileage meter sensor collects the pulse number × 12 × 60/(the pulse number per revolution × the tire rotation speed per kilometer), namely, the vehicle speed (Km/h) is obtained according to the ratio of the pulse number per hour to the tire rotation speed per kilometer.
However, the load capacity of the commercial vehicle is much larger than that of a domestic vehicle, and the load distribution range is wider, so that the variation ranges of the speed ratios of the axle main reduction ratio and the gearbox odometer are larger, and when the speed ratios of the rear axle main reduction ratio and the gearbox odometer are changed, the speed ratio state of the instrument needs to be increased, so that the types of the instrument are increased, and the production assembly of a production line is complicated.
In addition, in order to meet the national standard requirements: when the speedometer is matched, the indicated speed of the instrument is necessarily greater than the actual speed, namely the vehicle is required to meet the following requirements when the vehicle is unloaded and fully loaded: when the speedometer is matched, the vehicle speed indicated by the instrument is greater than the actual vehicle speed, so that the speedometer is inaccurate, for example, the radius of a tire of the vehicle is 0.52m when the vehicle is unloaded, the vehicle speed indicated by the instrument is 80Km/h, the actual vehicle speed is 79.8Km/h, the vehicle speed indicated by the instrument is basically consistent with the actual vehicle speed, but the radius of the tire is compressed to 0.46m by gravity along with the reasons of increasing the load of the vehicle and the like, the vehicle speed indicated by the instrument is 80Km/h, but the actual vehicle speed is 70.6Km/h, so that the actual vehicle speed is far less than the vehicle speed indicated by the instrument, and the difference between the vehicle. Meanwhile, the accumulated mileage of the vehicle is determined by the speed multiplied by the time, so that the accumulated mileage of the odometer is seriously inaccurate, and the accuracy of related calculation of components needing speed information, such as a vehicle fuel consumption meter, a driving recorder, an engine and the like, can be indirectly influenced.
Disclosure of Invention
The invention provides a method and a system for calculating the vehicle speed of a commercial vehicle, which solve the problem that the vehicle speed acquisition mode in the prior art cannot meet the requirement of the commercial vehicle.
The invention provides a method for calculating the speed of a commercial vehicle, which comprises the following steps:
acquiring the distance between the center of the driving shaft and the ground as the radius of the tire;
acquiring the rotating speed of a driving wheel per minute of a vehicle as the rotating speed of a tire;
and acquiring the vehicle speed according to the tire radius and the tire rotating speed.
Preferably, the method further comprises:
acquiring the distance between the center of a driving shaft and the ground when the vehicle is stationary as an initial tire radius;
the acquiring a distance between the center of the drive shaft and the ground as a tire radius includes:
acquiring distances between centers of a plurality of different positions of the driving shaft and the ground respectively as alternative tire radiuses;
and calculating whether the difference value between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, taking the initial tire radius as the current tire radius, and if not, taking the average value of the candidate tire radii as the current tire radius.
Preferably, the method further comprises:
calibrating a relation comparison table of tire pressure and tire radius in advance;
monitoring tire pressure while obtaining the tire radius;
correcting the radius of the tire according to the current tire pressure and a relation comparison table of the tire pressure and the radius of the tire to obtain a first corrected tire radius;
the obtaining of the vehicle speed according to the tire radius and the tire rotation speed comprises:
and acquiring the vehicle speed according to the first corrected tire radius and the tire rotating speed.
Preferably, the method further comprises:
calibrating a relation comparison table of the load and the radius of the tire in advance;
monitoring the load while obtaining the tire radius;
correcting the tire radius according to the current load and the relation comparison table of the load and the tire radius to obtain a second corrected tire radius;
the obtaining of the vehicle speed according to the tire radius and the tire rotation speed comprises:
and acquiring the vehicle speed according to the second corrected tire radius and the tire rotating speed.
Preferably, the method further comprises:
calibrating a relation comparison table of the load and the radius of the tire in advance;
monitoring the load while obtaining the first corrected tire radius;
correcting the first corrected tire radius according to the current load and the relation comparison table of the load and the tire radius to obtain a third corrected tire radius;
the obtaining the vehicle speed according to the first corrected tire radius and the tire rotation speed comprises:
and acquiring the vehicle speed according to the third corrected tire radius and the tire rotating speed.
Preferably, the method further comprises:
after the vehicle speed is acquired, the driving mileage of the vehicle is acquired according to the vehicle speed.
Correspondingly, the invention also provides a vehicle speed calculating system of the commercial vehicle, which comprises the following components:
the system comprises a combination instrument, a radar, an anti-lock braking system and a power supply, wherein the power supply supplies power to the combination instrument and the anti-lock braking system, the anti-lock braking system is connected with the combination instrument through a CAN bus, and the radar is connected with the combination instrument;
the radar is used for collecting the distance between the center of the driving shaft and the ground and sending the distance to the combination instrument;
the anti-lock braking system is used for sending a message containing information of the rotating speed of the vehicle per minute converted to the driving wheel to the combination instrument through the CAN bus;
the combination instrument is used for taking the distance between the center of the received driving shaft and the ground as the radius of a tire, taking the rotating speed of the received vehicle reduced to the driving wheel per minute as the rotating speed of the tire, and then calculating the speed of the vehicle according to the radius of the tire and the rotating speed of the tire and displaying the speed.
Preferably, the number of the radars is three, the radars are respectively arranged at the left end, the right end and the middle position of the driving shaft and are used for acquiring the distance between the center of the left end, the center of the right end and the middle position of the driving shaft and the ground as the radius of each alternative tire;
the system further comprises:
the hand brake switch is connected with the combination instrument and used for sending a hand brake signal to the combination instrument; and
the foot brake switch is connected with the combination instrument and used for sending a foot brake signal to the combination instrument;
the combined instrument is used for taking the average value of the radius of each alternative tire as the initial tire radius when the hand brake signal and/or the foot brake signal are received, the tire rotating speed is zero, and the difference between the radius of the maximum alternative tire and the radius of the minimum alternative tire is smaller than a set threshold value; and when the hand brake signal and/or the foot brake signal are not received, calculating whether the difference value between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, taking the initial tire radius as the current tire radius, and if not, taking the average value of the candidate tire radii as the current tire radius.
Preferably, the system further comprises:
the tire pressure monitoring controller is connected with the combination instrument through a CAN bus and is used for sending a message containing tire pressure information to the combination instrument;
the combination instrument is used for storing a relation comparison table of tire pressure and tire radius, correcting the tire radius according to the current tire pressure and the relation comparison table of the tire pressure and the tire radius after receiving the tire pressure information to obtain a first corrected tire radius, and then acquiring the vehicle speed according to the first corrected tire radius and the tire rotating speed.
Preferably, the system further comprises:
the load sensing sensor is connected with the combination instrument and used for acquiring vehicle-mounted weight information and sending the vehicle-mounted weight information to the combination instrument;
the combination instrument is used for storing a relation comparison table of load and tire radius, correcting the tire radius according to the current load and the relation comparison table of the load and the tire radius after receiving vehicle-mounted weight information to obtain a second corrected tire radius, and then acquiring the vehicle speed according to the second corrected tire radius and the tire rotating speed.
The invention provides a method and a system for calculating the vehicle speed of a commercial vehicle, comprising the following steps: the distance between the center of the driving shaft and the ground is obtained and used as the radius of the tire, and the actual distance between the center of the driving shaft and the ground is used as the radius of the tire instead of a preset value, so that the accuracy of the radius of the tire is effectively improved; and then acquiring the rotation speed of the driving wheel per minute of the vehicle as the rotation speed of the tire, and acquiring the vehicle speed according to the radius of the tire and the rotation speed of the tire. The vehicle speed calculation method provided by the invention does not need to utilize parameters such as the traditional rear axle main reduction ratio, the transmission case odometer speed ratio and the like, so that various instruments do not need to be equipped for the commercial vehicle to adapt to the rear axle main reduction ratio and the transmission case odometer speed ratio corresponding to different load capacities, the complexity of production and assembly is greatly simplified, and the calculation result is more accurate because the radius of the tire and the rotating speed of the tire are actual values of the current vehicle.
Further, the method and system for calculating the vehicle speed of the commercial vehicle provided by the embodiment of the invention obtain the initial tire radius of the vehicle in a stationary state, then obtain the distances between the centers of a plurality of different positions of the driving shaft and the ground as the candidate tire radii respectively, and calculate whether the difference between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, the initial tire radius is used as the current tire radius, and if not, the average value of the candidate tire radii is used as the current tire radius. Effectively avoid like this because of there being the inaccurate condition of tire radius that the road surface exists the obstacle, the road surface roughness low grade reason leads to acquireing to take place: when the tire radius data meet the requirements, the latest data is used as the current tire radius, and when the tire radius data do not meet the requirements, the initial tire radius which meets the requirements recently is used as the current tire radius, so that the accuracy of the acquired vehicle speed can be guaranteed. In addition, the tire radius of the vehicle in a static state and a moving state can also be changed, so that the tire radius acquired in real time is more accurate.
Further, the method and the system for calculating the vehicle speed of the commercial vehicle, provided by the embodiment of the invention, calibrate the comparison table of the relationship between the tire pressure and the radius of the tire in advance, and correct the radius of the tire according to the current comparison table of the relationship between the tire pressure and the radius of the tire, so that the obtained radius of the tire is effectively improved to be more accurate.
Further, the method and the system for calculating the vehicle speed of the commercial vehicle, provided by the embodiment of the invention, calibrate the comparison table of the relationship between the load and the radius of the tire in advance, and correct the radius of the tire according to the current load and the comparison table of the relationship between the load and the radius of the tire, so that the obtained radius of the tire is effectively improved to be more accurate.
Drawings
In order to more clearly illustrate the embodiments of the present application or technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments described in the present invention, and other drawings can be obtained by those skilled in the art according to the drawings.
FIG. 1 is a first flowchart of a method for calculating a vehicle speed of a commercial vehicle according to an embodiment of the present invention;
FIG. 2 is a second flowchart of a method for calculating a vehicle speed of a commercial vehicle according to an embodiment of the present invention;
FIG. 3 is a third flowchart of a method for calculating a vehicle speed of a commercial vehicle according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a first configuration of a vehicle speed calculating system for a commercial vehicle according to an embodiment of the present invention;
fig. 5 is a second structural diagram of a vehicle speed calculating system of a commercial vehicle according to an embodiment of the invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar parameters or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
According to the method and the system for calculating the vehicle speed of the commercial vehicle, the current tire radius of the vehicle is obtained, and the vehicle speed is obtained according to the tire radius and the tire rotating speed obtained in real time. In addition, data such as a rear axle main reduction ratio, a gearbox odometer speed ratio and the like are not needed in the process of calculating the vehicle speed, so that corresponding speedometers do not need to be prepared according to different rear axle main reduction ratios and gearbox odometer speed ratios, the requirements of all commercial vehicles can be met by only using one speedometer provided by the invention, and the complexity of assembly of a production line is greatly reduced.
In order to better understand the technical scheme and technical effect of the present invention, the following detailed description will be made on specific embodiments with reference to a flow diagram. As shown in fig. 1, a first flowchart of a vehicle speed calculating method for a commercial vehicle according to an embodiment of the present invention may include the following steps:
in step S01, the distance between the center of the drive shaft and the ground is acquired as the tire radius.
In this embodiment, a distance between the center of the driving shaft and the ground can be obtained in real time by using a sensor such as a radar, which is more precise than the prior art that uses a set value as the radius of the tire, for example, when the tire pressure, the vehicle load, the external temperature, the vehicle driving state (static, moving, or moving speed is different), and the like are changed, the radius of the tire is changed, and when the set value is used as the radius of the tire, the calculation result of the vehicle speed is definitely deviated in a non-standard state. The invention adopts the current monitored distance between the center of the driving shaft and the ground as the radius of the tire, and the current actual radius (the actual measurement value) of the tire can ensure the accuracy of the vehicle speed calculated according to the radius of the tire.
And step S02, acquiring the rotating speed of the driving wheel per minute of the vehicle as the rotating speed of the tire.
In this embodiment, the real-time rotation speed may be obtained by a rotation speed sensor, and then the real-time rotation speed is converted into the rotation speed of the vehicle folding per minute driving wheel by an electronic control unit, such as an electronic control unit of the combination meter, of course, other electronic control units, such as an ABS, may also be used to send the rotation speed of the vehicle folding per minute driving wheel to the electronic control unit of the combination meter.
In one embodiment, the ABS outputs a CAN message every 50ms when the vehicle is reduced in the rotational speed of the driving wheel per minute, the combination meter receives the CAN message every 50ms from the ABS, and the rotational speed information included in the CAN message is used as the rotational speed of the driving wheel per minute.
And step S03, acquiring the vehicle speed according to the tire radius and the tire rotating speed.
In the present embodiment, the vehicle speed may be calculated using the formula (1):
vehicle speed equivalent to the rotating speed of driving wheel per minute x the radius of the driving wheel x 60(1)
The current vehicle speed of the vehicle can be calculated through the formula (1), and of course, other formulas can be adopted to calculate the current vehicle speed, which is not limited herein. After the vehicle speed is obtained, the vehicle speed can be displayed by a speedometer of the combination meter.
In other embodiments, the method may further comprise:
after the vehicle speed is acquired, the driving mileage of the vehicle is acquired according to the vehicle speed. Specifically, the driving range of the vehicle is obtained by accumulation or integration. Of course, the driving range may be displayed by an odometer, which will not be described in detail herein. Because the vehicle speed is determined through the real-time tire radius and the tire rotating speed, the vehicle running speed is accurate when the vehicle is in no-load, load and environment temperature change, and the accuracy of the accumulated mileage is indirectly improved
According to the vehicle speed calculation method of the commercial vehicle, the distance between the actual center of the driving shaft and the ground is used as the radius of the tire, and a preset value is not used as the radius of the tire, so that the accuracy of the radius of the tire is effectively improved; and then acquiring the rotation speed of the driving wheel per minute of the vehicle as the rotation speed of the tire, and acquiring the vehicle speed according to the radius of the tire and the rotation speed of the tire. The vehicle speed calculation method provided by the invention does not need to utilize parameters such as the traditional rear axle main reduction ratio, the gearbox odometer speed ratio and the like, so that various instruments do not need to be equipped for commercial vehicles to adapt to the rear axle main reduction ratio and the gearbox odometer speed ratio corresponding to different load capacities, the complexity of production and assembly is greatly simplified, and the calculation result is more accurate because the radius of the tire and the rotating speed of the tire are actual values of the current vehicle.
Fig. 2 shows a second flowchart of a vehicle speed calculating method for a commercial vehicle according to an embodiment of the invention.
In this embodiment, the method further includes:
in step S21, the distance between the center of the drive shaft and the ground when the vehicle is stationary is acquired as the initial tire radius.
In the present embodiment, considering that the distance between the center of the drive shaft and the ground measured in real time does not always accurately reflect the radius of the tire, for example, when there is a road block on the road surface, and the sensor passes over the road block, the measured distance between the center of the drive shaft and the ground is smaller than the true radius of the tire due to the height of the road block, and if the distance is taken as the radius of the tire, the calculation result is inaccurate, so when there is a road block, the flatness of the road surface, etc., causes the distance between the center of the drive shaft and the ground to deviate from the true radius of the tire, it is necessary to give a value closer to the true radius of the tire in order to calculate the vehicle speed, for this purpose, the distance between the center of the drive shaft and the ground when the vehicle is stationary is obtained as the initial radius of the tire, and since the distance between the, of course, in order to ensure the accuracy of the acquired value of the initial tire radius, it is possible to further judge the reliability of the distance between the center of the drive shaft and the ground, for example, by setting a plurality of radars to monitor whether the distances between the centers of the drive shaft and the ground at different positions coincide, and if so, regarding the value as the initial tire radius, as the tire radius of the vehicle at rest. Of course, in other embodiments, in order to simplify the technical solution, the initial tire radius may also be set to a preset value, which is not limited herein.
The acquiring a distance between the center of the drive shaft and the ground as a tire radius includes:
in step S22, distances between the centers of the plurality of different positions of the drive shaft and the ground are acquired as candidate tire radii, respectively.
In the present embodiment, in order to ensure the reliability of the acquired data of the tire radius, the distances between the centers of the plurality of different positions of the drive shaft and the ground are acquired respectively, so that the reliability of the acquired data can be judged from the dispersion of the plurality of distances, for example, when the distance acquired by a certain radar is significantly small compared with the distances acquired by other radars due to the obstacle on the road, it can be considered that the reliability of the currently acquired distance is not high and cannot be regarded as the tire radius.
And step S23, calculating whether the difference value between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, taking the initial tire radius as the current tire radius, and if not, taking the average value of the candidate tire radii as the current tire radius.
In the present embodiment, the set threshold may be empirically or experimentally determined, for example, 0.01 m, 0.02 m, 0.025 m, 0.03 m, or the like. In addition, the reliability of the obtained data of the tire radius can be checked through indexes such as dispersion, and other methods which can be used for checking the distance between the center of the driving shaft and the ground can be used as the tire radius are all applicable.
It should be noted that the radius information of the wheel can be collected in real time through the steps in the running process of the vehicle, the radius of the tire can be collected once when the vehicle is static, and the radius of the tire collected when the vehicle is static last time is adopted before the vehicle is static next time, so that the amount of information collection, processing and occupation of computing resources and network resources can be effectively reduced, and the system efficiency is improved.
The method provided by the invention can simply and accurately acquire the radius of the tire in real time, has the capability of identifying error data, can screen out data which do not meet the requirements, and ensures the accuracy of the acquired radius of the tire.
Fig. 3 shows a third flowchart of a vehicle speed calculating method for a commercial vehicle according to an embodiment of the invention.
In this embodiment, in order to improve the accuracy of the acquired vehicle speed, the acquired tire radius is further corrected, and the accuracy of the acquired tire radius is effectively improved.
In one embodiment, the method further comprises:
and step S31, calibrating a relation comparison table of the tire pressure and the radius of the tire in advance.
Step S32, monitoring the tire pressure while obtaining the tire radius.
And step S33, correcting the radius of the tire according to the current tire pressure and the relation comparison table of the tire pressure and the radius of the tire to obtain a first corrected tire radius. For example, the tire pressure information, that is, the initial calibration values of different tire radii in different tire pressure ranges are obtained through the CAN bus, so that a more prepared wheel radius CAN be obtained when an accurate wheel radius cannot be obtained. Of course, the tire pressure may be used to correct the tire radius obtained in real time.
The obtaining of the vehicle speed according to the tire radius and the tire rotation speed comprises: and acquiring the vehicle speed according to the first corrected tire radius and the tire rotating speed.
In another embodiment, the method further comprises:
in step S34, a relationship table between the load and the tire radius is calibrated in advance.
In step S35, the load is monitored while obtaining the tire radius. For example, in order to ensure the accuracy of the vehicle speed, the system is also provided with a load sensing sensor for sensing the load of the vehicle.
And step S36, correcting the tire radius according to the current load and the relation comparison table of the load and the tire radius to obtain a second corrected tire radius. For example, the vehicle has calibration values for the tire radius of different loads, i.e. different tire radii are assigned to each 0.1, 0.2, 0.3 or 0.4 ton load, i.e. the tire radius under different loads is corrected.
The obtaining of the vehicle speed according to the tire radius and the tire rotation speed comprises: and acquiring the vehicle speed according to the second corrected tire radius and the tire rotating speed.
In yet another embodiment, the method further comprises:
in step S37, a relationship table between the load and the tire radius is calibrated in advance. The comparison table is different from the comparison table in step S034, and is a comparison table in consideration of the relationship between the load and the tire radius in the case of the tire pressure.
In step S38, the load is monitored while the first corrected tire radius is obtained.
Step S39, correcting the first corrected tire radius according to the current load and the relation comparison table of the load and the tire radius to obtain a third corrected tire radius;
the obtaining the vehicle speed according to the first corrected tire radius and the tire rotation speed comprises:
and acquiring the vehicle speed according to the third corrected tire radius and the tire rotating speed.
According to the method for calculating the vehicle speed of the commercial vehicle, provided by the embodiment of the invention, the measured radius of the tire is corrected, so that the radius of the tire can meet the precision requirement under various conditions, and the vehicle speed obtained according to the radius of the tire is more accurate.
Correspondingly, the invention also provides a vehicle speed calculating system of a commercial vehicle corresponding to the method, as shown in fig. 4, which is a first structural schematic diagram of the vehicle speed calculating system of the commercial vehicle provided by the embodiment of the invention, and the system may include:
the power supply supplies power to the combination instrument and the anti-lock braking system, the anti-lock braking system is connected with the combination instrument through a CAN bus, and the radar is connected with the combination instrument.
The power supply can be a storage battery and the like, and the radar is used for collecting the distance between the center of the driving shaft and the ground and sending the distance to the combination instrument. And the anti-lock braking system is used for sending a message containing the information of the rotating speed of the reduced driving wheel per minute of the vehicle to the combination instrument through the CAN bus. The combination instrument is used for taking the distance between the center of the received driving shaft and the ground as the radius of a tire, taking the rotating speed of the received vehicle reduced to the driving wheel per minute as the rotating speed of the tire, and then calculating the speed of the vehicle according to the radius of the tire and the rotating speed of the tire and displaying the speed.
For example, the three radars are respectively arranged at the left end, the right end and the middle position of the driving shaft, and are abbreviated as a left radar, a right radar and a middle radar for collecting the distance between the center of the left end, the right end and the middle position of the driving shaft and the ground as each candidate tire radius. The system further comprises:
the hand brake switch is connected with the combination instrument and used for sending a hand brake signal to the combination instrument; and the foot brake switch is connected with the combination instrument and used for sending a foot brake signal to the combination instrument.
The combined instrument is used for taking the average value of the radius of each candidate tire as the initial tire radius when the hand brake signal and/or the foot brake signal are received and the difference between the radius of the maximum candidate tire and the radius of the minimum candidate tire is smaller than a set threshold value; and when the hand brake signal and/or the foot brake signal are not received, calculating whether the difference value between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, taking the initial tire radius as the current tire radius, and if not, taking the average value of the candidate tire radii as the current tire radius.
In one embodiment, the system cancels the traditional speedometer, uses a rear axle main reduction ratio and a gearbox odometer speed ratio, and directly obtains the running speed of the vehicle by the reduction of the rotating speed of a driving wheel per minute x the radius of a tire x 60 of the vehicle. The rotating speed of the driving wheel per minute converted by the vehicle is obtained through an ABS controller node on the CAN bus, and the ABS node outputs the rotating speed of the driving wheel once every 50ms, so that the instrument CAN calculate and update the vehicle speed conveniently. The vehicle is arranged on the left side and the right side of a drive axle, a distance measuring radar is arranged in the middle of the drive axle, when the vehicle is in a stop state, for example, a combination meter IPC detects that a hand brake switch K1 is in a closed state and/or a foot brake switch K2 is in a closed state, and at the moment, a CAN message from an ABS displays that the rotating speed of a drive wheel is 0, the distance between the center of the drive axle and the ground is measured, the value is an accurate value of the current wheel radius, the real accurate vehicle speed of the vehicle is calculated by using the value, but the value is not accurate under the condition of uneven road surface, namely the measured distance is inaccurate data when the difference of 3 distances measured by the distance measuring radar exceeds a set threshold value, and.
Fig. 5 is a second schematic structural diagram of a vehicle speed calculating system of a commercial vehicle according to an embodiment of the invention.
In one embodiment, the system may further comprise:
and the tire pressure monitoring controller TPMS is connected with the combination instrument through a CAN bus and is used for sending a message containing tire pressure information to the combination instrument IPC. The combination instrument IPC is used for storing a relation comparison table of tire pressure and tire radius, correcting the tire radius according to the current tire pressure and the relation comparison table of the tire pressure and the tire radius after receiving the tire pressure information to obtain a first corrected tire radius, and then obtaining the vehicle speed according to the first corrected tire radius and the tire rotating speed.
In another embodiment, the system further comprises:
and the load sensing sensor is connected with the combination instrument IPC and used for acquiring vehicle-mounted weight information and sending the vehicle-mounted weight information to the combination instrument IPC. The combination instrument IPC is used for storing a relation comparison table of the load and the tire radius, correcting the tire radius according to the current load and the relation comparison table of the load and the tire radius after receiving vehicle-mounted weight information to obtain a second corrected tire radius, and then obtaining the vehicle speed according to the second corrected tire radius and the tire rotating speed.
Specifically, the IPC acquires the tire pressure value from the TPMS through the CAN bus, and the tire radius is the current tire radius × the current tire-under-tire-pressure tire radius correction coefficient (calibration value) × the current under-load tire radius correction coefficient (calibration value). The radius correction coefficient of the tire under the current tire pressure and the radius correction coefficient of the tire under the current load are calibrated through experiments during vehicle development.
In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that the invention as claimed requires more features than are expressly recited in each claim.
Those skilled in the art will appreciate that the modules in the apparatus of an embodiment may be adaptively changed and disposed in one or more devices other than the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that although embodiments described herein include some features included in other embodiments, not other features, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments may be used in any combination.
The various component embodiments of the invention may be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It will be appreciated by those skilled in the art that a microprocessor or Digital Signal Processor (DSP) may be used in practice to implement some or all of the functions in a system for multi-operator remote manipulation of a single operator according to embodiments of the present invention. The present invention may also be embodied as apparatus or system programs (e.g., computer programs and computer program products) for performing a portion or all of the methods described herein. Such programs implementing the present invention may be stored on computer-readable media or may be in the form of one or more signals. Such a signal may be downloaded from a website on the internet, provided on a carrier signal, or provided in any other form.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps or the like not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several systems, several of these systems may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.
Claims (6)
1. A method for calculating a vehicle speed of a commercial vehicle, comprising:
acquiring the distance between the center of the driving shaft and the ground as the radius of the tire;
acquiring the rotating speed of a driving wheel per minute of a vehicle as the rotating speed of a tire;
acquiring a vehicle speed according to the tire radius and the tire rotating speed;
further comprising:
calibrating a relation comparison table of tire pressure and tire radius in advance;
monitoring tire pressure while obtaining the tire radius;
correcting the radius of the tire according to the current tire pressure and a relation comparison table of the tire pressure and the radius of the tire to obtain a first corrected tire radius;
acquiring a vehicle speed according to the first corrected tire radius and the tire rotating speed;
acquiring the distance between the center of a driving shaft and the ground when the vehicle is stationary as an initial tire radius;
the acquiring a distance between the center of the drive shaft and the ground as a tire radius includes:
acquiring distances between centers of a plurality of different positions of the driving shaft and the ground respectively as alternative tire radiuses;
and calculating whether the difference value between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, taking the initial tire radius as the current tire radius, and if not, taking the average value of the candidate tire radii as the current tire radius.
2. The method of claim 1, further comprising:
calibrating a relation comparison table of the load and the radius of the tire in advance;
monitoring the load while obtaining the tire radius;
correcting the tire radius according to the current load and the relation comparison table of the load and the tire radius to obtain a second corrected tire radius;
the obtaining of the vehicle speed according to the tire radius and the tire rotation speed comprises:
and acquiring the vehicle speed according to the second corrected tire radius and the tire rotating speed.
3. The method of claim 1, further comprising:
calibrating a relation comparison table of the load and the radius of the tire in advance;
monitoring the load while obtaining the first corrected tire radius;
correcting the first corrected tire radius according to the current load and the relation comparison table of the load and the tire radius to obtain a third corrected tire radius;
the obtaining the vehicle speed according to the first corrected tire radius and the tire rotation speed comprises:
and acquiring the vehicle speed according to the third corrected tire radius and the tire rotating speed.
4. The method according to any one of claims 1 to 3, further comprising:
after the vehicle speed is acquired, the driving mileage of the vehicle is acquired according to the vehicle speed.
5. A vehicle speed calculation system for a commercial vehicle, comprising:
the system comprises a combination instrument, a radar, an anti-lock braking system and a power supply, wherein the power supply supplies power to the combination instrument and the anti-lock braking system, the anti-lock braking system is connected with the combination instrument through a CAN bus, and the radar is connected with the combination instrument;
the radar is used for collecting the distance between the center of the driving shaft and the ground and sending the distance to the combination instrument;
the anti-lock braking system is used for sending a message containing information of the rotating speed of the vehicle per minute converted to the driving wheel to the combination instrument through the CAN bus;
the combination instrument is used for taking the distance between the center of the received driving shaft and the ground as the radius of a tire, taking the rotating speed of the received vehicle converted per minute of the driving wheel as the rotating speed of the tire, and then calculating the speed of the vehicle according to the radius of the tire and the rotating speed of the tire and displaying the speed;
further comprising:
the tire pressure monitoring controller is connected with the combination instrument through a CAN bus and is used for sending a message containing tire pressure information to the combination instrument;
the combination instrument is used for storing a relation comparison table of tire pressure and tire radius, correcting the tire radius according to the current tire pressure and the relation comparison table of the tire pressure and the tire radius after receiving tire pressure information to obtain a first corrected tire radius, and then acquiring the vehicle speed according to the first corrected tire radius and the tire rotating speed;
the number of the radars is three, the radars are respectively arranged at the left end, the right end and the middle position of the driving shaft and are used for acquiring the distance between the centers of the left end, the right end and the middle position of the driving shaft and the ground as the radius of each alternative tire;
the system further comprises:
the hand brake switch is connected with the combination instrument and used for sending a hand brake signal to the combination instrument; and
the foot brake switch is connected with the combination instrument and used for sending a foot brake signal to the combination instrument;
the combined instrument is used for taking the average value of the radius of each alternative tire as the initial tire radius when the hand brake signal and/or the foot brake signal are received, the tire rotating speed is zero, and the difference between the radius of the maximum alternative tire and the radius of the minimum alternative tire is smaller than a set threshold value; and when the hand brake signal and/or the foot brake signal are not received, calculating whether the difference value between the maximum candidate tire radius and the minimum candidate tire radius exceeds a set threshold value, if so, taking the initial tire radius as the current tire radius, and if not, taking the average value of the candidate tire radii as the current tire radius.
6. The system of claim 5, further comprising:
the load sensing sensor is connected with the combination instrument and used for acquiring vehicle-mounted weight information and sending the vehicle-mounted weight information to the combination instrument;
the combination instrument is used for storing a relation comparison table of load and tire radius, correcting the tire radius according to the current load and the relation comparison table of the load and the tire radius after receiving vehicle-mounted weight information to obtain a second corrected tire radius, and then acquiring the vehicle speed according to the second corrected tire radius and the tire rotating speed.
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| CN201710734909.3A CN107554529B (en) | 2017-08-24 | 2017-08-24 | Method and system for calculating vehicle speed of commercial vehicle |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108407812B (en) * | 2018-02-01 | 2020-02-21 | 北京长城华冠汽车技术开发有限公司 | Method and system for correcting wheel diameter after tire replacement |
| CN109017800B (en) * | 2018-08-27 | 2024-03-19 | 一汽解放汽车有限公司 | Commercial vehicle speed processing device based on whole vehicle controller |
| CN109455090A (en) * | 2018-11-20 | 2019-03-12 | 安徽江淮汽车集团股份有限公司 | The adjustable combination instrument of speed and control method |
| CN111409647B (en) * | 2020-03-31 | 2023-04-07 | 潍柴动力股份有限公司 | Vehicle speed correction method and device and vehicle |
| CN113734237B (en) * | 2021-11-03 | 2022-02-08 | 比亚迪股份有限公司 | Method for determining wheel diameter of vehicle, storage medium and electronic device |
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