JP2000283831A - Apparatus for determining vehicle weight and lane gradient - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an apparatus for determining the vehicle weight and the lane gradient whereby the vehicle weight and the lane gradient can be mutually independently calculated. SOLUTION: The determining apparatus is incorporated in an ECU 1 of a vehicle and calculates the true driving force F during travel from various sensor signals and a required driving force F0 for obtaining the same acceleration as its true acceleration dV/dt while an empty vehicle is traveling a flat road, thereby calculating the difference thereof as a load resistance RF. About the load resistance RF and true acceleration dV/dt, their time changes ΔRF and Δ(dV/dt) are calculated, the vehicle weight W is calculated from the time change characteristics of the load resistance ΔF due to the time change of the true acceleration dV/dt during travel of vehicle, and the lane gradient θis calculated from the calculated vehicle weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for determining a vehicle weight and a running road gradient from data obtained during running.

[0002]

2. Related Background Art For example, Japanese Patent Application Laid-Open No. 9-79363 discloses a technique for obtaining predetermined vehicle load degree information from driving force and acceleration data obtained during running of a vehicle. This vehicle load information is defined from the difference between the acceleration when the vehicle is traveling on a flat road and the actual acceleration while the vehicle is traveling. When the vehicle travels on an uphill road with the vehicle loaded, the load is extremely large, On the other hand, when the vehicle runs on a flat road in an empty state, the load degree is minimal, that is, close to zero. Therefore,
According to the above-described known technique, it is considered that it is possible to determine whether the vehicle is in the state of traveling uphill on a loaded vehicle or traveling flat on an empty vehicle based on the magnitude of the obtained load degree.

[0003]

However, since the above-mentioned load degree is expressed as a function of the vehicle weight and the traveling road gradient, it is not suitable for discriminating the magnitude of only one of them. Specifically, when the load obtained during traveling is medium, it is not possible to determine whether the load is obtained depending largely on the vehicle weight or the traveling road gradient. .

[0004] In this regard, if a means for detecting any one of the data of the vehicle weight and the gradient of the traveling road is added to the above-mentioned known technique, an arithmetic operation is performed based on the obtained load degree and one of the detected data. Can calculate the other data, but in this case, at least one sensor is required. The present invention has been made based on the above-described circumstances, and has as its object the purpose of calculating the vehicle weight and the running road gradient separately without using special sensors. It is to provide a determination device.

[0005]

According to the vehicle weight and traveling road gradient determining apparatus of the present invention (first aspect), first, from known data of actual driving force and actual acceleration during traveling,
The load resistance of the vehicle is calculated. More specifically, the load resistance is defined by the difference between the actual driving force during traveling and the driving force required to obtain the same acceleration as the actual acceleration when traveling on a flat road vehicle. Next, a time change amount of the load resistance and the actual acceleration during traveling are calculated, and a vehicle weight is calculated from a time change amount of the load resistance according to the time change of the actual acceleration. Then, if the vehicle weight is calculated, the traveling road gradient is calculated from the vehicle weight.

The principle of calculating the vehicle weight in the above-described determination device is that the load resistance of the vehicle is expressed as a function of only the actual acceleration when the vehicle weight during traveling is constant and there is no rapid change in the gradient of the traveling road. In this case, the characteristic is based on the characteristic that the time change amount of the load resistance accompanying the time change of the actual acceleration linearly increases and decreases depending on the vehicle weight. Therefore, if the actual acceleration and the time change amount of the load resistance are respectively obtained, the theoretical value of the vehicle weight, that is, the estimated vehicle weight is calculated from the relationship between the time change amount of the load resistance and the vehicle weight due to the time change of the actual acceleration. It is possible.

On the other hand, the absolute amount of the load resistance uniformly increases and decreases depending on the magnitude of the traveling road gradient, regardless of the temporal change of the actual acceleration. Therefore, if the vehicle weight is calculated as described above, the traveling road gradient can be dynamically calculated from the vehicle weight. Note that the vehicle weight can be accurately calculated in a running state in which the actual acceleration is changing, rather than in a steady running state of the vehicle. Preferably, the operation is performed when it is greater than the threshold.

Preferably, when calculating the above-described traveling road gradient, considering that the gradient θ on the actual traveling road is gentle, cos θ = 1 and sin θ = 1 in the vector calculation notation for the vehicle weight on the traveling road surface. The calculation can be performed assuming θ. In this case, the gradient calculation can be facilitated within a practical range.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the apparatus for determining the weight of a vehicle and the gradient of a traveling road of the present invention will be described below. The determination device of the embodiment is applied to a connected vehicle including a tractor and a trailer, and the tractor of the connected vehicle is equipped with a diesel engine. However, the vehicles to which the present invention is applied are not particularly limited to connected vehicles, and include trucks, buses,
It can be widely applied to passenger cars and the like.

Referring to FIG. 1, a determination apparatus according to an embodiment is shown in a schematic block configuration. This determination device is incorporated in an electronic control unit (ECU) 1 provided in the connected vehicle, and can function in various control routines executed by the ECU 1, for example, a control routine of an automatic transmission. Although not particularly shown, the connected vehicle of the embodiment is equipped with an automatic transmission having a mechanical clutch, and the automatic transmission control reflects, for example, a driver's intention to shift using fuzzy inference. The shift speed is selected and the shift timing is optimized.

The ECU 1 is connected to sensors for detecting various data obtained while the connected vehicle is traveling. These sensors include an engine speed sensor 2, a rack position sensor 4, and an exhaust brake operation switch. 6, a clutch rotational speed sensor 8, a shift gear stage sensor 10, and the like. The above-described engine speed sensor 2 detects the speed of the output shaft of the engine and outputs a speed signal Ne. The rack position sensor 4 detects a control rack position of the fuel injection pump and outputs a rack position signal SRC. The on / off signal EB is output from the exhaust brake operation switch 6 in conjunction with the switching.

The clutch speed sensor 8 outputs a clutch speed signal Nc, and the shift speed sensor 10 outputs a current shift speed signal Gp. The operation of the automatic transmission in the connected vehicle is controlled by the control circuit 12 in the ECU 1, and the determination device of the present embodiment can supply useful control parameters for the control circuit 12 to the control circuit 12.

Referring to FIG. 2, there is shown an automatic transmission control routine executed by the ECU 1. Hereinafter, the configuration and function of the apparatus for determining the vehicle weight and the traveling road gradient will be described in detail according to the procedure of this flowchart. I do. First, in step S10, necessary sensor signals are read from the various sensors described above. Note that the sensor signals read into the ECU 1 are input to the operation blocks 20 and 22, respectively, as shown in FIG.

[0014] Next, in step S12, the loaded engine torque T _E based on the sensor signal, the vehicle speed V and the actual acceleration dV / dt is calculated. Specifically, in the operation block 20, the engine speed Ne, based on the rack position SRC and the on / off signal EB, the torque T _E is determined actually engine is generated from a prepared torque map. Then, the obtained engine torque T _E
Is supplied to the next operation block 24.

On the other hand, in the operation block 22, the vehicle speed V is obtained based on the clutch speed Nc and the gear stage Gp.
The vehicle speed V obtained here is supplied to the next processing block 26 and calculation block 28, respectively. Then, in a processing block 26, the actual acceleration dV / d is obtained by differentiating the vehicle speed V.
t is required. In the next step S14, various operation signals described above, that is, the engine torque T _E, with respect to the vehicle speed V and the acceleration dV / dt, respectively filtering is performed. This filter processing can be executed by, for example, a low-pass filter (not shown) in the ECU 1.

Next, the load resistance R _F of the vehicle at step S16 is calculated. The load resistor R _F is, can be calculated from the calculation result of a plurality of operation blocks 24, 28, 30. Specifically, the gear stage signal Gp described above is adapted to be inputted to the arithmetic block 24, the calculation block 24, a known vehicle on the basis of the supplied engine torque T _E and the gear signal Gp specifications From the beginning, the driving force (tractor traction force) actually exerted in the vehicle, that is, the actual driving force F is calculated.

Assuming that the actual driving force F is the vehicle weight W and the traveling road gradient θ, the actual driving force F is expressed by both sides of the following equation (1) from the equation of motion of the vehicle. _{T E · γ T · γ F} · η / R D = (W + W R) / g · dV / dt + (μcosθ + sinθ) · W + λ · A · V 2 ··· (1) Here, gamma _T : Transmission gear ratio (running gear) γ _F : Final reduction gear ratio η: Drive train transmission efficiency _RD : Drive wheel tire effective radius W _R : Rotating portion equivalent weight g: Gravitational acceleration μ: Rolling resistance coefficient λ: Air Resistance coefficient A: Projected area on the front of the vehicle Further, the weight W _R corresponding to the rotating portion differs depending on whether the vehicle is running in acceleration or deceleration or running by inertia, and is expressed by the following formula in each case.

[0018] _{W R = g · {I W} + (I F + I E · γ T 2) · γ F 2} / R D 2 ( acceleration and _{deceleration) W R = g · (I} W + I F · γ F 2 ) / R _D ² (during coasting) here, I _W: wheels and wheel moment of inertia I _F of the same rotating parts: final reduction input shaft and the moment of inertia I _E of the same rotation parts: a transmission input shaft and the engine output shaft It is the moment of inertia for the same rotation. As is apparent from the above equation (1), the actual driving force F is calculated based on the engine torque _TE and the known vehicle specifications by the equation (1).
Can be calculated from the left side of.

In the operation block 28, the air resistance F _{A of the} vehicle is calculated from the vehicle speed V. Air resistance F _A has the formula (1)
And is represented by F _A = λ · A · V ² . The calculated air resistance F _A and the actual acceleration dV / dt described above are input to the calculation block 30. In the calculation block 30, the actual acceleration dV / dt and the air resistance F _A
From the equation of motion of the vehicle, is necessary driving force F ₀ considerable time flat road unladen travel is calculated based on. More specifically, the required driving force F ₀ is defined as a driving force required to obtain the same acceleration as the current actual acceleration dV / dt when the vehicle runs on a straight flat road in an empty state. It is represented by both sides of (2).

[0020] _{T E0 · γ T · γ F} · η / R D = (W 0 + W R) / g · dV / dt-μ · W 0 -F A ··· (2) herein, T _E0: flat required engine torque W equivalent during road unladen running _0: empty car as is clear from (motorbike) weight above equation (2), required driving force F ₀ considerable time flat road unladen traveling, air resistance F _a, the actual acceleration dV It can be calculated from the right side of the above equation (2) based on / dt and known vehicle specifications.

The load resistance R _F is defined by the difference between the actual driving force F and the necessary driving force F ₀ corresponding to running on a flat road. Therefore, when the actual driving force F and the required driving force F ₀ are respectively calculated as described above, the difference between the actual driving force F and the required driving force F ₀ is obtained by the subtraction unit 32. load resistance R _F of the vehicle is obtained. Then, the load resistance R _F calculated by the subtraction unit 32 is supplied to the next operation block 34.

[0022] Note that the load resistor R _F is the definition above, the above equation (1) can be expressed by the following equation (2) (3). _{R F = T E · γ T} · γ F · η / R D - (W 0 + W R) / g · dV / dt-μ · W 0 -F A ··· (3) In addition, the automatic shift control routine With the execution, in the next step S18, it is determined whether or not the vehicle is in a connected state. This determination can be made, for example, based on a trailer connection signal supplied from the coupler.

If the vehicle is in the connected state, the result of the determination in step S18 is true (Yes), and in this case, step S20 is executed next. On the other hand, when the vehicle is in the single vehicle state, the determination result is false (No), and step S22 is executed. The procedure when the vehicle is in the single vehicle state will be described later. In step S20, it is determined whether or not a value of a vehicle weight W described later has already been determined. In the first time of the control routine, the vehicle weight W has not been determined yet, so the determination result in the first step S20 is false (No), and then step S24 is executed.

In step S24, the above-described load resistance R
Time variation of _F and the actual acceleration dV / dt, i.e., the load resistance variation [Delta] R _F and the actual acceleration change amount Δ (dV / dt) is calculated. The calculation of these change amounts ΔR _F and Δ (dV / dt) is performed in operation blocks 34 and 36, respectively. Specifically, in these operation blocks 34 and 36, the load resistance R _F and the actual acceleration dV / dt are calculated. The difference between the current value and the previous value is calculated as the load resistance change amount ΔR _F and the actual acceleration change amount Δ (dV / dt).

The load resistance change amount ΔR _F calculated in the operation block 34 is calculated by the following operation block 3 together with the load resistance R _F.
8 is supplied. The calculation block 38 is also supplied with the actual acceleration change amount Δ (dV / dt) calculated in the calculation block 36. In the next step S26, it is determined whether or not the obtained actual acceleration change amount Δ (dV / dt) exceeds a predetermined threshold. Specifically, in the calculation in the next step S28, division by the actual acceleration change amount Δ (dV / dt) is performed. Can be set to a value.

Now, when the vehicle is accelerating and decelerating, the actual acceleration change amount Δ (dV / dt) is sufficiently large to exceed the above-mentioned threshold value, so that the determination result in step S26 is true,
Next, step S28 is executed. In step S28, the vehicle weight W is calculated. Specifically, the arithmetic At block 38, based on the supplied load resistance variation [Delta] R _F and the actual acceleration change amount delta (dV / dt), the actual acceleration dV / dt load resistance variation [Delta] R _F with time change of From the characteristics of the following equation (4)
Is used to determine the vehicle weight W.

W = m · g + W ₀ (4) where m = ΔR _F / Δ (dV / dt). Here, the calculation principle of the vehicle weight W in the calculation block 38 will be described in detail. First, from the definition of the load resistance R _F ,
(1) and the load resistor R _F from the right side of the equation (2) can be expressed by the following equation (5).

R _F = (W−W ₀ ) / g · dV / dt + {(μcos θ + sin θ) · W−μ · W ₀ } (5) In the above equation (5), the change in the actual acceleration dV / dt Paying attention to the time change amount of the load resistance R _F associated with the above, since the roadway gradient θ hardly changes over time and can be ignored, the load resistance change amount ΔR _F and the actual acceleration change amount Δ (dV / dt) Is represented by the following equation: ΔR _F = (W−W ₀ ) / g · Δ (dV / dt) (6)

From the above equations (5) and (6), the inventor of the present invention has found that the vehicle load resistance R _F when the vehicle weight W during traveling is constant and there is no rapid change in the traveling road gradient θ. it is one of interest to be expressed as a function of only the actual acceleration dV / dt, it can be calculated from the time variation of the load resistance R _F with time change of the actual acceleration dV / dt of the vehicle weight W theoretically Have confirmed. Another advantage is that the load resistance _RF is not affected by the transmission gear ratio.

[0030] In this case, as is apparent from equation (6), the time variation of the load resistance R _F with time change of the actual acceleration dV / dt is determined depending on the vehicle weight W, the characteristics of the vehicle It increases in proportion to the weight W. Therefore, if the ratio (ΔR _F / Δ (dV / dt)) between the actual acceleration change amount and the load resistance change amount is obtained, the vehicle weight W can be calculated from the above equation (4). In addition,
When the vehicle is traveling at a constant speed (steady traveling), the actual acceleration change amount Δ (dV / dt) is 0, and the vehicle weight W cannot be calculated. In this case, the above-described step S2
The determination result in step 6 is false, and the process proceeds to step S30 without executing step S28.

In step S30, the vehicle weight W is held at the previous value, that is, the value calculated in the previous calculation cycle. Note that, at the first time of the control routine, the vehicle weight W
Is not calculated, in this case, for example, an appropriate initial value is given as the vehicle weight W. Next, step S
At 32, it is determined whether or not the calculated value of the vehicle weight W has converged. Specifically, when the vehicle weight W obtained for each calculation cycle of the control routine is sequentially accumulated and the value is substantially stabilized, the determination result in step S32 becomes true. In this case, step S34 is executed next, and the vehicle weight W obtained in the operation block 38 is determined. Then, the determined vehicle weight W is output from the calculation block 38.

On the other hand, the value of the obtained vehicle weight W is discrete for each calculation cycle, and the determination result in step S32 is false while the value is not stable yet. In this case, step S
34 is not executed, and the calculation block 38 simply outputs the vehicle weight W obtained for each calculation cycle. After the execution of step S34 and the determination of the vehicle weight W, the determination result in step S20 becomes true from the next calculation cycle, and the above-described processing in steps S24 to S34 is not executed. In this case, a fixed value is always used as the vehicle weight W.

When the vehicle weight W is calculated as described above,
Next, step S36 is executed. And step S
In 36, the traveling road gradient θ is calculated from the vehicle weight W. Specifically, the running road gradient θ is calculated in the calculation block 40, and in the calculation block 40, the running road gradient θ is calculated based on the vehicle weight W supplied from the calculation block 38. The running path gradient θ is calculated by using the load resistance R _F and the actual acceleration dV / dt, which have already been obtained by, for example, a modification of the equation (5).
It can be calculated from (7).

[0034] _{μcosθ + sinθ = (R F -m} · dV / dt + μ · W 0) / W ··· (7) In addition, in the weight cargo vehicles with such articulated vehicle travels extreme steep path Therefore, the actual travel path is usually on the order of ± 10%. On such a gentle slope, the calculation of the equation (7) can be simplified by setting cos θ = 1 and sin θ = θ (rad) in the vector component notation with respect to the traveling road surface of the vehicle weight. In this case, the running road gradient theta can be calculated from the following _{equation, θ = {R F -m ·} dV / dt-μ · (W-W 0)} / W ··· (8).

As described above, the apparatus for determining the vehicle weight and the running road gradient according to the present embodiment can separately calculate the vehicle weight W and the running road gradient θ as specific numerical values. Further, from the calculated values W and θ, it is possible to clearly determine how much the load of the vehicle is and whether the vehicle is actually traveling on a graded road.

If the result of the determination in step S18 is false, that is, if the vehicle is in a single tractor state, the roadway gradient θ is calculated in step S38 instead of step S36. In step S38, the known single vehicle weight W ₀ is determined regardless of the vehicle weight W calculation procedure described above.
Is calculated from the driving road gradient θ. In this case, W = W ₀ , and therefore m = 0, the operation block 4
At 0, the traveling road gradient θ is simply calculated by the following equation: θ = R _F / W ₀ (9) In this case, the traveling road gradient θ can be calculated as a specific numerical value even in the single vehicle state, and it is possible to accurately determine whether the road is an uphill road or a flat road.

The vehicle weight W and the traveling road gradient θ obtained by the determination device are calculated in the ECU 1 by a calculation block 3 respectively.
8, and 40 are supplied to the control circuit 12. Thereafter, in the automatic shift control routine, a process of forming a shift control signal is performed by executing step S40. In the control circuit 12,
Various control parameters are supplied from sensors and other calculation blocks (not shown).
Based on these parameters and the supplied information on the vehicle weight W and the traveling road gradient θ, the target shift speed is determined from a shift map prepared in advance.

When a predetermined driver's will quantification fuzzy rule is established, the driver's will is determined, and if a shift operation is performed based on the determined driver's will, a control circuit is executed. 12 outputs a predetermined shift control signal. In this case, the control circuit 12
Since the information of the vehicle weight W and the information of the traveling road gradient θ are separately supplied to the control circuit 12, the control circuit 12 uses the information of W and θ, for example, to run the vehicle on an uphill road (W is small and θ is large). Alternatively, it can be accurately determined whether the vehicle is running on a flat road (W is large and θ is small). Therefore, the control circuit 12 can set an appropriate shift timing according to the gradient of the traveling road irrespective of the loaded state of the vehicle, and can greatly contribute to the reduction of the shift shock.

On the other hand, since the determination device of the present invention can numerically calculate the vehicle weight and the traveling road gradient, for example, the operation control and the ABS control of a known hill start assist device and a parking assist (parking support) device. Further, the present invention can be used for an engine brake auxiliary system, an operation control of an exhaust brake, and the like. In addition, the present invention can be implemented in various modifications without being limited to the above-described embodiment. For example, the calculation of the vehicle weight W may be calculated from a map previously plotted relationship between the load resistance change amount [Delta] R _F with respect to the actual acceleration change amount Δ (dV / dt). Further, in the operation block 40, the traveling road gradient θ may be calculated from the equation (1). In this case, the block configuration of FIG. 1, the actual driving force F in place of the load resistor R _F is supplied to the operation block 40.

[0040]

As described above, according to the vehicle weight and traveling road gradient judging device of the present invention (claim 1), the vehicle weight and traveling road gradient can be obtained from only the known data obtained during the traveling of the vehicle. The slope can be calculated numerically. Therefore, it is possible to provide not only the determination of an empty or loaded vehicle, or the determination of a flat road or an uphill road, but also accurate information on vehicle weight and traveling road gradient, and use for other vehicle traveling control technologies. It is also suitable for.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a determination device according to an embodiment.

FIG. 2 is a flowchart of an automatic shift control routine using the determination device of the embodiment.

[Explanation of symbols]

 1 ECU 32 Subtraction unit (load resistance calculation means) 34 Calculation block (load resistance change calculation means) 36 Calculation block (actual acceleration change calculation means) 38 Calculation block (vehicle weight calculation means) 40 Calculation block (travel road slope calculation) means)

Claims (1)

[Claims] A difference between an actual driving force during traveling of a vehicle and a driving force required to obtain the same acceleration as the actual acceleration obtained by the actual driving force when the vehicle is traveling on a flat road vehicle is determined by the following equation. Load resistance calculation means for calculating as load resistance; actual acceleration change amount calculation means for calculating the time change amount of the actual acceleration; load resistance change amount calculation means for calculating the time change amount of the load resistance; A vehicle weight calculating means for calculating a vehicle weight from a time change amount of the load resistance according to a time change of the vehicle weight; and a gradient calculating means for calculating a traveling road gradient from the calculated vehicle weight. And a device for determining a traveling road gradient.