JP2020011555A - Rank travel system - Google Patents

Abstract

To provide a rank travel system that stabilizes a change of an inter-vehicular distance, on the basis of an excess tractional force change caused by a loading change and a gradient change and by making use of a retarder function provided in a power system.SOLUTION: A rank travel system for making a plurality of vehicles travel in a rank includes an engine, an engine retarder, an automatic transmission, a transmission retarder, an electronic control brake, a parking brake, a forward recognition device, a longitudinal acceleration sensor and an inter-vehicular communication device. An excess tractional force is calculated by detecting self-weight and a road grade, and traveling is performed in a setting in which a following vehicle has higher retarder ability and in a range in which the accelerating/decelerating ability of the vehicle with the lowest excess tractional force among the vehicles constituting the rank is not exceeded.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a platooning running system that adapts to changes in conditions such as its own weight and road gradient.

  The Energy ITS project of the New Energy Industrial Technology (NEDO) was promoted from 2008 to 2013. Research report that air resistance is improved and fuel efficiency is improved by running in platoon with shorter inter-vehicle distance, research report of algorithm to control inter-vehicle distance shorter and more stable, compensating for danger of inter-vehicle collision due to shorter inter-vehicle distance Non-Patent Literatures 1 to 5 disclose research reports on a braking system, and research reports that express the longitudinal motion characteristics of a vehicle involved in inter-vehicle distance control by mathematical expressions.

  Non-Patent Document 1 describes that running in a platoon with a short inter-vehicle distance improves air resistance and fuel efficiency.

  Non-Patent Document 2 discloses a system (CACC: cooperative type) in which the ACC (Adaptive Cruise Control system: an inter-vehicle distance control system) can share the acceleration / deceleration information of another vehicle by inter-vehicle communication to shorten the inter-vehicle distance compared to the ACC. As an algorithm for applying ACC) to a heavy-duty truck, a control law for controlling the "inter-vehicle time" by replacing the inter-vehicle distance with time is described.

  Non-Patent Documents 3 and 4 disclose a two-system brake system in order to increase the reliability of a brake system in platooning in which a plurality of vehicles travel in a row. This two-system brake system compensates for avoiding rear-end collision by shortening the "inter-vehicle time".

  In addition, Non-Patent Document 5 describes a vehicle model expressing the longitudinal motion of a vehicle (heavy-duty truck) up to a steady running without gear shifting and a quasi-steady running with gear shifting.

  Furthermore, toward the practical use of the above-mentioned technology, development of the practical use of the next-generation public transportation system is being promoted in the "Stematic Innovation Creation Program (SIP)" led by the Cabinet Office.

  On the other hand, the automation of driving / braking devices for commercially available vehicles has been progressing, and in a mechanical automatic transmission controlled in cooperation with an engine, Patent Document 1, which performs control to make a torque required by a driver, a target deceleration and a vehicle There are Patent Literature 2 that calculates a target braking force from weight, and Patent Literature 3 that describes a parking brake that also supports unmanned automatic driving.

  Patent Literature 1 describes that engine torque is controlled when gears of a mechanical automatic transmission mounted on a large vehicle such as a truck or a bus are switched.

  Patent Literature 2 describes an equation for calculating a vehicle weight. It is described that the target deceleration is calculated by dividing the estimated vehicle weight by the target deceleration.

  Further, Patent Document 3 describes that even when the driver is not in the vehicle, the parking brake is released for the start of work and the parking brake is applied for the end of work. I have.

JP-A-2017-30529 JP 2014-118065 A Japanese Patent No. 6184045

"Examination of the effect of platooning trucks on running resistance and fuel efficiency on expressways" Hotaka Yamazaki et al., Automotive Research 32 (3) 2013, p.139-143 "Development of Inter-Vehicle Distance Control Algorithm for Coordinated ACC of Heavy Trucks" Ogama Gaku et al., Journal of Automotive Engineering, Vol.44, No.6, November 2013, No.20134868, p.1509-1515. "Study on Improvement of Reliability of Brake System in Platoon Running (1st Report)" Masahiko Aki et al., May 2011 Automotive Engineering Society Academic Lecture, No.348-20115307 "Investigation of Improvement of Reliability of Braking System in Platoon Running (2nd Report)" Yoshimasa Suzuki et al., May 2011 Automotive Engineering Society Academic Lecture, No.349-20115389 "Identification of longitudinal motion of heavy truck and its model method" Fujio Hagiyama et al., Transactions of the Society of Automotive Engineers of Japan, Vol.43, No.2, March 2012, No.20124209, p.211-216.

  In platooning, it is ideal that the distance between the vehicles that make up the platoon is always constant, but in practice the leading vehicle driven by humans tends to decelerate when entering a straight line to a curve. , Increasing speed to escape from curve to straight line, deceleration tendency including downshift on uphill road, engine brake, retarder brake, service brake on downhill road, service brake after downshifting, and switching of traffic flow and signal Speed up and down are repeated to adapt to the surrounding situation.

  The propagation of the change to the succeeding vehicle tends to increase the inter-vehicle distance when the vehicle speed is increasing and to decrease when the vehicle is decelerating. If the leading car continued to run at the speed limit vehicle speed, the delay that occurred once in the following vehicle could not be recovered, and even when running in a vehicle speed range lower than the speed limit vehicle speed, the speed control capability of each succeeding vehicle was uneven due to the difference in loaded weight. As a result, inter-vehicle extension and inter-vehicle shortening occur. Therefore, it is necessary to make the leading vehicle travel in the performance range of the vehicle with the lowest speed control capability based on the speed control capability of each vehicle constituting the platoon (Problem 1).

  For that purpose, each vehicle forming the platoon needs to always know the surplus traction force (that is, the possible acceleration) of the vehicle and have a formula for calculating the accelerator opening that generates the acceleration required from the preceding vehicle. It is necessary to provide a means for detecting vehicle weight, road gradient, air resistance, and rolling resistance, which are variables in the calculation formula (Problem 2).

Each vehicle in the platoon is equipped with an electro-mechanical automatic transmission (hereinafter, abbreviated as AMT, Automated Mechanical Transmission). This AMT is used to reduce the drive torque from the engine to the drive wheels during gear shifting. There is a "torque break" in which the transmission is cut off, and the driving force control during that time is interrupted, so speed control based on that is necessary (Problem 3).
However, Non-Patent Document 1 does not mention any measures for shortening the inter-vehicle distance while exhibiting the effect of shortening the inter-vehicle distance by reducing the inter-vehicle distance and running in a platoon to improve air resistance and improve fuel efficiency.

  Although the control law for maintaining the following distance in Non-Patent Document 2 is indicated as “target acceleration + interval time + vehicle speed”, the sum of different physical quantities cannot be used as it is as design data as it is, and the sum of different physical quantities cannot be used. There remains a problem of adapting to a situation where the load capacity differs, a situation where the road gradient changes, and a condition where a gear shift is required.

Although Non-Patent Documents 3 and 4 is by setting higher maximum deceleration as following vehicles for vehicle rear-end collision avoidance, regulations deceleration by commercial vehicle brake regulations UN-R13 (MFDD: 5.0m / S 2 or more) lower limit There is a problem that the maximum deceleration, which is higher for the following vehicles in the meantime, is guaranteed by guaranteeing the operation of the ABS, with the deceleration determined by the road surface friction coefficient as the upper limit. Here, MFDD is an abbreviation for Mean Fully Developed Deceleration and means the average deceleration in ABS operation.

  Non-Patent Document 5 merely identifies a model and an actual vehicle, and does not mention application to a platooning system. It merely points out the speed fluctuations caused by gear shifting of automatic transmissions, but does not mention measures to suppress them and apply them to platooning systems.

  Patent Literature 1 only controls engine torque in order to improve drivability while shortening the time for gear switching, and does not mention application to a platooning system.

  Patent Literature 2 shows a vehicle weight calculation formula using engine torque, vehicle acceleration, and other parameters as parameters, but also influences transmission efficiency from engine torque to driving force and road gradient, air resistance, and rolling resistance related to vehicle acceleration. No description is found.

  Patent Literature 3 discloses that “the shift lever is in the parking position, the parking brake is applied, the service brake is applied, the engine is started, the start gear is engaged, the service brake is released, the parking brake is released. The starting process from whether the vehicle has been released or the vehicle has started '', and whether the service brake has been applied, the gears have been neutralized, the parking brake has been applied, the engine has been stopped, or the service brake has been released The operation control flow of the parking start in the “parking process leading to” is shown. The above-mentioned problem becomes a problem in the "running process" which is located between the flows of the "starting process" and the "parking process".

  In order to solve the above-mentioned problems, the platooning system according to the present invention is configured such that a plurality of vehicles in the platoon are set to have a higher deceleration ability as a succeeding vehicle, and each vehicle detects its own weight and a road gradient to obtain an excess. A platoon ECU for calculating tractive force is provided, and the vehicle runs under the control of the platoon ECU so as not to exceed the acceleration capability of the vehicle having the lowest surplus traction force among the vehicles.

Vehicles other than at least the leading vehicle among the plurality of vehicles traveling in the line are retarders (auxiliary brakes), electromechanical fully automatic transmissions, electronic control brakes, forward recognition sensors, longitudinal acceleration sensors (incline sensors may be used). ) And an inter-vehicle communication device.
In the system of the present invention, it is also possible to cruise while holding in a specific gear for the purpose. Further, the retarder may be either an engine retarder or a mission retarder.

  In this way, the inter-vehicle distance shortening direction at the time of deceleration is set to the extension direction by combining the electronic control brake with the engine braking effect and / or the transmission tardder braking effect.

  According to the present invention, while performing platooning, the inter-vehicle distance increases when the leading vehicle accelerates, and shortens when decelerating.However, the width of the extension or shortening can be reduced, and stable platooning can be performed. It can be carried out.

It is explanatory drawing of detection of inter-vehicle distance, inter-vehicle speed, and inter-vehicle acceleration and a control amount. It is explanatory drawing of the general expression of a power performance curve. FIG. 4 is an explanatory diagram of shift points of a multi-gear electromechanical fully automatic transmission. FIG. 3 is an explanatory diagram of a mathematical model expressing power performance by acceleration. FIG. 9 is an explanatory diagram of a flow of a vehicle speed calculation using a mathematical model expressed by acceleration. FIG. 4 is an explanatory diagram of an acceleration performance curve using a hyperbolic constant as an index. It is explanatory drawing of the calculation chart which calculates | requires an own weight and estimates an accelerator opening degree using a hyperbolic constant as an index. It is explanatory drawing of road gradient estimation calculated | required from an accelerometer and wheel speed. It is explanatory drawing of the flowchart of an acceleration control. FIG. 2 is an explanatory diagram of a system configuration concept relating to a longitudinal movement of a platoon running system. FIG. 7 is an explanatory diagram of a speed rise curve in the case of upshifting at an engine rotation higher than a torque peak point. FIG. 8 is an explanatory diagram of a speed rise curve in the case of upshifting at an engine rotation lower than a torque peak point. FIG. 5 is an explanatory diagram of a deceleration enhancing effect by a combination of a gear ratio and a retarder. FIG. 4 is an explanatory diagram of the effect of using a retarder together with the main brake deceleration. It is a control flow explanatory diagram of formation in a row.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
Vehicles other than the leading vehicle among the plurality of vehicles forming the platoon are provided with sensors (laser or image sensor) for recognizing the front. Note that a front recognition sensor may be provided in the leading vehicle. In this way, the leading vehicle and the following vehicle can be exchanged.
FIG. 1 shows the detection of the inter-vehicle distance, the inter-vehicle acceleration, the speed and acceleration of the preceding vehicle, and the control amounts. As described above, the inter-vehicle distance difference with respect to the target of the inter-vehicle distance with the preceding vehicle is grasped by the laser or the image sensor. The inter-vehicle speed is obtained by differentiating the inter-vehicle distance difference, and the inter-vehicle acceleration is obtained by differentiating the inter-vehicle speed.

  When the own vehicle speed is added to the inter-vehicle speed, the speed of the preceding vehicle can be determined, and the preceding vehicle speed can be differentiated to determine the acceleration of the preceding vehicle. The own vehicle speed is differentiated to find the own vehicle acceleration. The control amount is configured using the physical amount obtained in this manner.

  As the control amount, the acceleration (A) for compensating for the difference in acceleration from the preceding vehicle of the vehicle to be controlled, the acceleration (B) for compensating for the difference between the target vehicle, and the detection delay of the difference between the acceleration and the vehicle speed are shown. Acceleration (C) for compensation is required. The sum of these three accelerations is defined as a control amount. Accordingly, the vehicle speed is equal to that of the preceding vehicle. Specifically, an accelerator% corresponding to the acceleration of (A) + (B) + (C) is set as the control amount. The acceleration corresponding to the accelerator% is calculated according to FIG.

  Each vehicle is equipped with various control units such as a platooning (automatic driving) ECU (Electric Control Unit), an engine ECU, an automatic transmission ECU, an electronic control brake ECU, and a vehicle control ECU.

  An explanation of the general expression of the power performance curve is shown in FIG. The extra traction is affected by its own weight and gradient. Although an example of a four-speed transmission is shown here, a multi-stage automatic transmission of 12 to 16 speeds is actually used. The engine torque characteristic of FIG. 2A is changed to the driving performance diagram of FIG. 2C through the gear ratio of FIG. 2B.

In FIG. 2c, G1, G2, G3, and G4 are driving torques of the respective gears, and _Dθ0 , _Dθ1 , and _Dθ2 are vehicle speed-dependent running resistances corresponding to 0%, θ1%, and θ2% of the road gradient. is there. The difference between the driving torque of each gear and the running resistance is the surplus traction force. When the weight increases due to the load, G1, G2, G3, and G4 decrease in proportion to the increase in the weight, and the excess tractive force decreases. For example, in the case of the second gear, P2- _Dθ0 is the surplus traction on flat ground, and P2- _Dθ2 is the surplus traction on the gradient θ2.

FIG. 3 is an explanatory diagram of shift points of a multi-stage AMT, which is a mainstream in a large truck, cited from Non-Patent Document 5. The speed change point when the accelerator is accelerated at 100% is indicated by a circle, the 75% acceleration is indicated by a triangle, the 50% acceleration is indicated by a square, and the 25% acceleration is indicated by a diamond.
The shift points for acceleration and deceleration are different. The gear shift point at the time of acceleration of 75% accelerator marked with a △ mark is shifted up from 1st gear to 2nd gear at a vehicle speed of 3 km / h and engine speed of 700 rpm, skipped up to 4th gear at 13 km / h and 1700 rpm, and 23 km / h, Skip shift up to 6th speed at 1800rpm, 31km / h, skip upshift to 8th speed at 1600rpm, 40km / h, skip upshift to 10th speed at 1250rpm, 53km / h to 11th speed at 1150rpm, 67km / h Upshifting to 12th with h.

  On the other hand, the downshift is set to shift down one step at a time when the engine speed drops to 665 rpm. What should be remembered here is that, on an expressway traveling at a speed of 50 to 60 km / h or more, the vehicle can be driven with gears held at 9th, 10th, 11th, and 12th speeds. The first car is geared to 12th (or 11th), the following car is geared to 11th (or 10th), and the succeeding car is geared to 10th (or 9th). I do.

FIG. 4 is an explanatory diagram of a mathematical model expressing power performance by acceleration. Vehicle longitudinal motion torque at the drive wheel engine torque T _E to the transmission gear ratio i _{mn ·} final gear ratio i _f is multiplied is the driving force. The vehicle mass m _eq involved in the vehicle longitudinal motion is converted into an equivalent inertia moment I _eq around the drive shaft to derive the rotational motion formula of the formula (1), and the rotational acceleration ω ′ is converted into the longitudinal acceleration α by the formula (2). Substituting and using the running resistances R _γ , R _d , R _{θ according} to equation (3) and the longitudinal acceleration α _γ , α _d , α _θ of the vehicle, the following equation (4) is used for the longitudinal motion. Here, the R _gamma rolling resistance, _{R d} is the air resistance, the R _theta is the gradient resistance. The _meq included in the following equation (2) depends on the load capacity. When m _eq changes and the gear ratio i _mn changes, α in equation (4) changes. This α becomes an acceleration equivalent to the surplus traction force. Here, equation (5) is a value corresponding to the acceleration of the net output of the engine.

FIG. 5 shows a flow of vehicle speed calculation using a mathematical model expressed by acceleration. The accelerator opening (%) is input from the required acceleration. The accelerator opening enters the AMT, engine, and engine retarder. The AMT selects a gear according to the accelerator opening and the vehicle speed. The engine speed _ne is determined from the vehicle speed and the gear.
The engine calculates an acceleration as an engine output from the engine rotation and the accelerator opening. The equation for calculating the engine acceleration is a straight line equation of y ₁ = c in the engine rotation range below the peak torque point, and y ₂ = ax + b in the engine rotation range above the peak torque. The acceleration value corresponding to the accelerator opening is calculated. Output. From this acceleration, the deceleration of air resistance, rolling resistance, and gradient resistance is subtracted and integrated to obtain the velocity.

On the other hand, with regard to deceleration, the combination of "the main brake that operates in proportion to the brake% corresponding to the brake pedal stroke" and "the retarder that acts on the engine brake when the accelerator is released" reduces the deceleration of the following vehicle. By increasing the value, "the tendency for the following vehicle to have a smaller inter-vehicle distance" is suppressed. This point will be described later in detail with reference to FIG.
The dominance of the retarder can be selected from non-operation, one-step operation, and two-step operation. Since the deceleration by the engine retarder is proportional to the engine rotation and the transmission retarder is proportional to the vehicle speed, the advantage of the engine retarder depends on the gear position and the vehicle speed, and the transmission retarder does not depend on the gear position but on the vehicle speed.

  The brake% is input from the required deceleration. Under this condition, since the accelerator opening is zero, the retarder also operates according to the operation intensity selection “zero, one stage, two stages”. The main brake produces a deceleration proportional to the brake%. Since this deceleration decreases depending on the increase in the load, an electronically controlled brake (EBS: Electronic Brake System) generates a deceleration corrected for reduction including a rolling resistance component. The deceleration due to the transmission retarder and the engine retarder are superimposed on the deceleration due to the EBS.

  It is necessary to provide a means for detecting a change in the vehicle weight that affects the surplus traction force. In order to detect a change in weight, it is necessary to provide a means for detecting a road gradient. FIG. 2 shows that the excess traction draws a hyperbola of the speed and the driving force. Further, FIG. 4 shows that the driving force can be represented by acceleration. Instead of the relationship between the speed and the driving force in FIG. 2, the relationship can be expressed as a relationship between the speed and the acceleration.

  FIG. 6 shows the measured acceleration of each gear when the accelerator is depressed 100% on a horizontal road, and the change in vehicle speed of the generated deceleration when coasting with the accelerator released, for the empty load and the 12t load. Things. The vehicle speed is set on the X axis, and the acceleration is set on the Y axis. The acceleration for each gear is shown above the X axis, and the coasting deceleration is shown below the X axis. Assuming that the sum of the acceleration and the deceleration is Y and the vehicle speed is X, a hyperbola of Y = aX is drawn, and the hyperbolic constant a is an index of a change in loading and a change in accelerator opening (%).

  FIG. 7 shows a calculation chart for estimating the self-weight by using the hyperbolic constant as an index to obtain the accelerator opening. The gross vehicle weight is on the X axis, the accelerator opening (%) is on the Y axis, and the hyperbolic constant is on the Z axis. The line Ap-B on the XZ coordinate shows the change of the hyperbolic constant with the increase in the gross vehicle weight, and the point AO is the hyperbolic constant when the vehicle is empty and the accelerator opening is 100%. Lines AC on the YZ coordinates indicate changes in the hyperbolic constant with a decrease in the accelerator opening. The line AC changes to a line Ax-Cx and further to a line BD with an increase in the total vehicle weight. Between the line CD and the line EF is a play allowance of the accelerator opening.

  A method for obtaining the total vehicle weight at an arbitrary point Zxy on the XYZ axes, a method for obtaining the hyperbolic constant, and a calculation method for obtaining the generated acceleration from the hyperbolic constant will be described below.

  The equation of the line Ap-B is represented by equations (6) and (7).

  The expression of the line AC is represented by Expressions (8) and (9).

  The expression of the line Ay-By is represented by Expressions (10) and (11).

  The expression of the line Ax-Cx is represented by Expressions (12) and (13).

  The expression of the line GH is represented by Expressions (14) and (15).

Own weight estimation in any accelerator can solve for X _L by simultaneous equations (10) and (12).
Converting equation (10) into equation _{X L} and (Equation 16).

The equation (12) is converted into an equation of K _xyz to obtain an equation (17).

  Expression (17) is substituted into Expression (16) to obtain (Expression 18).

Substituting equation (8) into equation (18) decomposes the gross vehicle weight _{X L.}

Thus, by substituting the current “vehicle speed × acceleration” into Z _xy of Expression (19) and substituting the current accelerator opening (%), the own weight (gross vehicle weight) _XL can be obtained.
Next, a method of calculating the accelerator opening according to the required acceleration will be described.
Equation (18) is converted to an equation of accelerator opening% (y).

By substituting equation (8) for Zy in equation (20) and equation (14) for Z _XO , equation 21 is obtained.

  Equation (21) is rearranged for the accelerator opening y to obtain (Equation 22).

  Formula (22) is further rearranged into (Formula 23).

  Equation (23) is decomposed with respect to the accelerator opening y to obtain equation (24).

Thus, the accelerator opening (%) y substitutes previously determined vehicle gross weight X ₁ of formula (24) (own weight), "vehicle speed (m / s ²⁾ to Z _xy × acceleration (m / s ² ) ".

  The value "Ax-Zxy" obtained by subtracting Zxy at the current accelerator opening y% from Ax at the accelerator opening 100% is an excess acceleration corresponding to the excess traction force. This acceleration is an acceleration corresponding to “actual measurement value + coasting deceleration + gradient resistance”.

  The required acceleration is required to be adjusted by adding or subtracting an acceleration component due to the gradient of the road on which the vehicle is currently traveling. FIG. 7 is an explanatory diagram of the road gradient obtained from the accelerometer and the wheel speed. The acceleration component of the wheel rotation and the road gradient component are superimposed on the longitudinal acceleration by the on-vehicle accelerometer. The longitudinal acceleration of the vehicle body is zero if the vehicle is stationary on a horizontal road, and the expression (25) is obtained by multiplying the acceleration of gravity (9.81) by Sin θ when stationary at a gradient θ. During traveling, the traveling acceleration is superimposed to obtain equation (26). From Expression (26), the road gradient can be obtained from Expression (27). Here, r is the rotation radius of the wheel, ω is the wheel rotation angular velocity, and ω ′ is the wheel rotation angular acceleration.

  Here, the flow of the acceleration control in which FIG. 1, FIG. 6, FIG. 7, and FIG. FIG. 9 is composed of three dotted lines: (A) state control of the own vehicle, (B) maintenance control of the platoon, and (C) operation control of the preceding vehicle.

In (A), the gradient is estimated from the accelerator%, accelerometer, and wheel speed sensors, the vehicle acceleration is calculated, the coasting deceleration is calculated, the sum of these is multiplied by the vehicle speed, and the current accelerator% is calculated. The weight is estimated by substituting into the empirical formula of the weight estimation.
(B) shows a different configuration of the contents in the lower part of FIG. The inter-vehicle distance to the preceding vehicle, the inter-vehicle speed, and the inter-vehicle acceleration are detected from the laser or the image sensor, and the control amount (acceleration) that keeps the inter-vehicle distance and follows the preceding vehicle is determined. (A) In addition to the feed gradient acceleration and the coasting deceleration, the speed is multiplied by the speed and substituted into a required acceleration accelerator opening formula to determine the accelerator opening and control the accelerator.
In (C), the following vehicle speed (= wheel speed) from (A) and the inter-vehicle speed from (B) are added to obtain the preceding vehicle speed. The preceding vehicle speed is subject to regulation of adherence to regulation speeds, including the following vehicle delay recovery speed. The driving of the preceding vehicle is controlled such that the acceleration of the preceding vehicle obtained by differentiating the speed does not exceed the surplus acceleration of the following vehicle ("Ax-Zxy" in FIG. 7).

  FIG. 10 shows a system configuration concept relating to the longitudinal movement of the platooning system. This is the side of the vehicle with the left side in front. From left, an electronically controlled diesel engine equipped with an engine retarder, an AMT, a transmission retarder, a propeller shaft, a differential gear, an EBS, a parking brake, and a rear axle are conceptually shown.

  Here, the engine retarder is a device that enhances the effectiveness of engine braking. Normal engine brakes slow down by not supplying fuel. In contrast, the engine retarder enhances deceleration by bleeding the compressed air in the compression process. The retarder effect can be changed depending on the number of cylinders in which this is performed.

  Transmission retarders reduce the rotation of the output shaft of a transmission, and there are two types: one is to reduce the speed by the law of electromagnetic induction and the other is to reduce the speed by a fluid effect. A control computer (ECU) is provided for each of the engine, transmission, and brake, and an automatic driving / platform running control computer (hereinafter, platoon-ECU) communicates with the in-vehicle LAN. Here, direct communication may be used regardless of the LAN.

  The parking brake is used when a vehicle releases and completes its duties without the help of a person, starts and ends a series of actions to park the vehicle, or stops or starts at a stopover, or causes an accident. It is involved in the emergency stop in the event of an emergency, automatic parking release / automatic parking operation, and is included in the system configuration related to the longitudinal movement of the platooning system.

  The platoon-ECU recognizes the lane and the position and attitude of the platoon preceding vehicle (hereinafter, the preceding vehicle) by a front sensor provided separately from the present invention, and runs following the vehicle. The platoon-ECU receives the target inter-vehicle distance and the required acceleration from the platoon leading vehicle, and determines the control amounts of (A), (B), and (C) in FIG. This required acceleration may use the acceleration of the preceding vehicle detected by the front sensor mounted on the following vehicle.

Before and after receiving the longitudinal acceleration from the acceleration sensor, LAN or receives wheel rotation from EBS-ECU, according to the method of Figure 7 of the previous unloading calculates the determined grade resistance alpha _gamma road gradient, receives the vehicle speed air resistance alpha _d The load is calculated by the method shown in FIG. 6 based on the calculated engine rotation, vehicle speed, accelerator opening, and road surface gradient. The control amount (acceleration) of FIG. 1 described above is calculated, and the accelerator opening corresponding to the control amount is calculated by equation (24).

  FIGS. 11 and 12 show a measure for improving the speed controllability by suppressing the influence of the torque interruption accompanying the gear shift. By setting the shift point (the engine speed) of the gear shift to the peak torque point and running in an engine rotation range lower than the peak torque point, torque interruption is reduced and speed control becomes smooth. FIG. 11 shows a speed increase curve in the case of an upshift at an engine rotation higher than the peak torque point, and FIG. 10 shows a speed increase curve in an upshift at an engine rotation lower than the peak torque point.

11 and 12, a gear ratio line drawn from the origin with the engine rotation relative to the vehicle speed as an axis, a peak torque point n _p , a lower engine rotation n ₁ for gear shifting and an upper engine rotation n ₂ for gear shifting on the left side. 3 shows a change in engine speed corresponding to. The right side shows a change in vehicle speed with respect to the time axis.

  The shift up process is as follows. That is, the clutch is disengaged, the current gear is disengaged, the engine speed is reduced to the engine speed corresponding to the up-shift gear (the rotation is synchronized), and the clutch is connected to the upper gear. Since the gear ratios of the respective gear stages are arranged in geometric series, the gear steps in the high engine speed range are wide, and the gear steps in the low engine speed range are narrow.

Therefore, in the engine rotation range higher than the peak torque point, the fluctuation width of the vehicle speed becomes large and mountainous because of the rightward downward torque (y ₂ = ax + b) and the relatively long synchronization time. At an engine rotation lower than the peak torque point, the torque is high and constant (y ₁ = c) and the synchronization time is relatively short, so that the fluctuation range of the vehicle speed is small and linear, and the acceleration increases as the gear becomes lower.

  Taking advantage of this tendency, speed change is performed quickly at a high torque in an engine rotation range lower than the peak torque point, and fluctuations in acceleration are suppressed, thereby stabilizing inter-vehicle control. For example, in a high-speed platoon cruising zone with a vehicle speed of 50 km / h or more, the leading vehicle fixes the gear at 12-speed, a succeeding vehicle with a 11-speed gear, and a succeeding vehicle with a 10-speed gear. The vehicle speed may be fixed at 11th speed, the succeeding vehicle at 10th speed, and the succeeding vehicle at 9th speed.

FIG. 13A shows a method of increasing the deceleration of a following vehicle by a combination of a gear ratio and a retarder based on actual vehicle experimental data. When coasting with gear neutral, a deceleration of 0.165 m / s ² occurs. When coasting with the gear 12 gear 0.215m / ^{s 2} of deceleration, deceleration of 0.23 m / ^{s 2} at 11 gear, further low-speed side of 0.298m / ^{s 2} and gear 10 gear , The deceleration becomes higher. This is the engine braking effect.

When the action one step retarder engine brake state 0.378m ^/ s 2 at 12-speed, 11-speed ^{0.48m / s 2, 10 0.529m /} s 2 and the deceleration in speed is increased by. When the action of the retarder in two stages 0.706m ^/ s 2 at 12-speed, 11-speed ^{0.781m / s 2, 0.95m / s} 2 and the deceleration is further increased by 10 speed by. Taking advantage of this tendency, for example, in the case of a three-unit platoon, if the leading car cruises at 12-speed, the succeeding car cruises at 11-speed plus one-stage retarder, and the succeeding car cruises at 10-speed plus two-stage retarder. The deceleration difference between the leading vehicle and the following vehicle is 0.265 m / s ² , and the deceleration difference between the following vehicle and the succeeding vehicle is 0.47 m / s ² .

  FIG. 13b shows the deceleration enhancing effect of only the gear and the deceleration enhancing effect of only the retarder. The leading car uses only the engine brake, the succeeding car uses the engine brake and one-stage retarder, and the succeeding car uses the engine brake and two-stage retarder to improve the tendency to decrease the inter-vehicle distance during deceleration. As a result, a safety margin against head-on collision can be obtained. Further, as described above, the lower stage gear may be used for the succeeding vehicle so as to further secure the safety margin against the rear-end collision.

  FIG. 14 shows the effect of using the retarder together with the main brake deceleration. This is an experimental analysis result with the gear fixed at the 11th speed. The generated deceleration with respect to the brake pedal stroke (%) indicates three types of deceleration: retarder OFF, one-stage retarder operation, and two-stage retarder operation. The use of the retarder increases the deceleration in a region where the brake stroke (%) is low, that is, reduces the braking delay. Since the retarder operates at zero accelerator stroke, it can be interpreted that the time delay until the start of the brake stroke is improved. From this effect, the braking delay at the time of platoon deceleration is improved, and the safety margin against head-on collision is increased.

  FIG. 15 is an explanatory diagram of the control flow of platoon formation. The figure shows a process in which the engine is started, the vehicle starts running, the vehicle runs alone, the vehicle enters the platoon, leaves the platoon, runs alone, parks, and stops the engine. Patent No. 6180405 describes a starting step and a parking step. The traveling process according to the present invention is inserted between the starting process and the parking process. The formation of the platoon may be divided into a platoon formation, a start of traveling, a stop, and then a release of the platoon, or a platoon formed during traveling and leaving. FIG. 15 describes the latter case.

  The running process will be described along the process numbers of processes 1, 2,. Start solo driving. The vehicle travels while repeating the gradient estimation (step 1), the self-weight estimation (step 2), and the surplus acceleration estimation (step 3), and updating. The gradient estimation is calculated by using Equation 27 in FIG. 8, and the self-weight estimation is calculated by using FIG. Enter ID after confirming ID. The vehicle travels while repeating the gradient estimation (step 6), the self-weight estimation (step 7), and the surplus acceleration estimation (step 8) while updating and sharing them in the platoon. Recognizing the order (first, succeeding, succeeding) of the vehicle in the platoon, setting the order deceleration (step 9, that is, selecting only the gear of FIG. 13a or 13b or only the retarder, and decelerating toward the rear. Then, the vehicle travels while adjusting the inter-vehicle distance (step 10) according to FIGS. After the steps 11 and 12, the vehicle leaves the platoon and returns to the independent running, performs its own mission, and shifts to the parking step.

  As described above, the present invention includes an engine equipped with an engine retarder, an automatic transmission, a transmission retarder, and an electronically controlled brake equipped with a forward recognition device, a longitudinal acceleration sensor, and a vehicle-to-vehicle communication device to estimate a road gradient and reduce a self-weight. Estimate, calculate the surplus traction force of the vehicle, perform deceleration settings according to the rank of each vehicle, and run in platoon so as not to exceed the lowest acceleration / deceleration ability of the vehicles shared and formed in the platoon. System.

  In addition, the present invention detects a difference with respect to a target inter-vehicle distance, a following inter-vehicle speed, an inter-vehicle acceleration, a preceding vehicle speed, and a preceding vehicle acceleration by detecting a difference between the target inter-vehicle distance and a sensor mounted on the own vehicle in response to the target acceleration and the target inter-vehicle distance. A platooning running system having a platoon ECU as means having a control rule for controlling with acceleration for compensating for a difference in acceleration from a vehicle, for compensating for a difference between a target vehicle, and for delay compensation.

  The present invention also provides a platoon having an platoon ECU equipped with an algorithm as a means for estimating a current vehicle weight (self-weight) from a current vehicle speed, a current gradient, and a current accelerator opening to obtain an excess traction force (excessive acceleration). It is a traveling system. By sharing the surplus traction force (excess acceleration) of each vehicle forming the platoon as a platoon, it becomes possible to run the vehicle in a range where the surplus traction force (excess acceleration) does not exceed the acceleration capability of the vehicle.

  Further, the present invention is a row running system having a row ECU as a means for setting a gear shift point to an engine peak torque point to suppress acceleration fluctuation due to torque interruption accompanying gear shift.

  In addition, the present invention avoids torque interruption by gear-holding the first car at 12th (or 11th), the succeeding car at 11th (or 10th), and the succeeding car at 10th (or 9th). Is a row running system having a row ECU as a means of running.

Further, the present invention is a system that suppresses the inter-vehicle change tendency that increases during acceleration and decreases during deceleration by setting the following vehicle to be excellent in acceleration and deceleration. The setting that the higher the succeeding vehicle is, the more excellent the acceleration is, the cruising gear is set to the first vehicle at the 12th (or 11th) speed, the succeeding vehicle at the 11th (or 10th) speed, and the succeeding vehicle at the 10th (or 9th) speed in that order. That is, the setting that the following vehicle is more excellent in deceleration means that the following vehicle will be set to lower gear sequentially and the leading car will use "engine brake only", the succeeding vehicle will use "engine brake and retarder one-step operation", later The continuation vehicle is a platooning running system having a platoon ECU as a means for cruising while setting to “use engine brake and two-stage retarder”.

Claims (9)

  In a platooning traveling system in which a plurality of vehicles travel in a line, specifications are set such that the deceleration ability of the plurality of vehicles is higher as the following vehicles, and each vehicle detects its own weight and a road gradient to calculate an excess traction force. A row running system comprising a row ECU and running under the control of the row ECU within a range not exceeding the acceleration capability of a vehicle having the lowest surplus traction force.   2. The platooning system according to claim 1, wherein at least one of the vehicles other than the leading vehicle is a retarder, an electro-mechanical fully automatic transmission, an electronic control brake, a front recognition sensor, a longitudinal acceleration sensor or a gradient sensor, an inter-vehicle communication device. A platooning system comprising:   2. The platooning system according to claim 1, wherein the forward recognition sensor detects a difference with respect to a target inter-vehicle distance, an inter-vehicle speed, an inter-vehicle acceleration, a preceding vehicle speed, and a preceding vehicle acceleration. A platooning system characterized in that the platooning system is controlled by a total acceleration of accelerations for compensating a difference in acceleration between the vehicle and a target vehicle, and for compensating for a delay.   The platooning system according to any one of claims 1 to 3, wherein the platoon ECU estimates an inclination, estimates its own weight, and obtains an accelerator opening which is an engine torque control amount with respect to a required acceleration. Platooning system. 5. The platooning system according to claim 1, wherein the platoon ECU includes a gradient estimating unit based on the equation (27), a vehicle gross weight estimating unit based on the equation (19), and a request based on the equation (24). A platooning system comprising means for determining an accelerator opening.   The platooning system according to any one of claims 1 to 5, wherein the platooning ECU includes an execution unit that applies an acceleration in an engine rotation range equal to or lower than an engine peak torque point. The platooning system according to any one of claims 1 to 6, wherein the platooning ECU includes means for performing gear-holding and enabling running while avoiding torque interruption. The platooning system according to any one of claims 1 to 7, wherein the platoon ECU uses only an engine brake for a leading vehicle, uses an engine brake and a one-stage retarder operation for a following vehicle, and uses an engine brake for a succeeding vehicle. A platooning system comprising means for cruising with use of a two-stage retarder.   The platooning system according to any one of claims 1 to 8, wherein the platooning ECU includes means for sequentially setting a low-speed gear from a leading vehicle to a following vehicle and cruising.

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