JP2021056061A - Vehicle weight estimation device and vehicle - Google Patents

Abstract

To provide a vehicle weight estimation device and a vehicle capable of appropriately estimating vehicle weight even when a driving force is transmitted to a driving wheel without passing through a driving force transmission device such as a clutch.SOLUTION: When step-in operation, in which the opening degree changes by the amount of change equal to or larger than a threshold, is performed on an accelerator pedal, a motor control part 102 causes a motor 11 to generate a first torque, which is a compensation torque for compensating the inertia moment of an electric vehicle 1 added to the torque corresponding to the opening degree. In a vehicle weight estimating part 103, a driving torque and acceleration at a first time point during acceleration of the electric vehicle 1 by the first torque are used for estimation of weight.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a vehicle weight estimation device and a vehicle that estimate the weight of a vehicle.

The weight of the vehicle is estimated, and the acceleration and deceleration of the vehicle are corrected using the estimated weight. Such corrections are particularly useful in large vehicles such as trucks, which are heavy and vary in weight depending on the load.

In order to accurately correct acceleration and deceleration, it is necessary to accurately estimate the weight of the vehicle. As a method for estimating the vehicle weight, for example, there is a technique disclosed in Patent Document 1. Patent Document 1 describes the vehicle acceleration in a state where the driving force is transmitted to the driving wheels, the vehicle acceleration in the state where the driving force is not transmitted to the driving wheels, and the vehicle traveling speed. A method of estimating vehicle weight is disclosed.

Japanese Unexamined Patent Publication No. 2002-13620

In recent years, electrification has been promoted even in large vehicles such as trucks. In an electric vehicle, the driving force generated by the motor is transmitted to the driving wheels without going through a driving force transmitting device such as a clutch.

In the technique disclosed in Patent Document 1, the driving force is transmitted to and disconnected from the driving wheels by a clutch. Therefore, in an electric vehicle, the vehicle weight cannot be estimated by using the technique disclosed in Patent Document 1.

An object of the present disclosure is to provide a vehicle weight estimation device and a vehicle capable of suitably estimating a vehicle weight even when the driving force is transmitted to the drive wheels without a driving force transmission device such as a clutch. ..

The vehicle weight estimation device according to one aspect of the present disclosure is a vehicle weight estimation device that estimates the weight of a vehicle, and is an accelerator opening sensor that detects the opening degree of the accelerator pedal and a drive torque based on the opening degree. The drive source to be generated, the drive source control unit that controls the drive source, the acceleration calculation unit that calculates the acceleration of the vehicle, and the drive torque and the acceleration at two or more time points while the vehicle is running. The drive source control unit has a vehicle weight estimation unit that estimates the weight based on the vehicle weight, and the drive source control unit performs a stepping operation on the accelerator pedal in which the opening degree changes by a change amount equal to or greater than a threshold value. A first torque is generated in the drive source by adding a compensation torque for compensating the inertial moment of the vehicle to a torque corresponding to the opening degree, and the vehicle weight estimation unit is accelerating the vehicle by the first torque. The driving torque and the acceleration at the first time point of the above are used for estimating the weight.

The vehicle according to one aspect of the present disclosure has the above-mentioned vehicle weight estimation device.

Even when the driving force is transmitted to the driving wheels without passing through a driving force transmitting device such as a clutch, the vehicle weight can be preferably estimated.

Diagram for exemplifying the configuration of an electric vehicle Block diagram for explaining the function of the control device Flow chart for explaining vehicle weight estimation processing by the control device

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below are examples, and the present disclosure is not limited to these embodiments.

FIG. 1 is a diagram for exemplifying the configuration of the electric vehicle 1. As shown in FIG. 1, the electric vehicle 1 includes a control device 10, a motor 11, an inverter 12, a battery 13, a propeller shaft 14, a differential gear 15, a drive wheel 16, a vehicle speed sensor 17, and an accelerator opening sensor 18. Have.

The control device 10 controls the operations of the motor 11, the inverter 12, and the battery 13. It should be noted that the control of each of the motor 11, the inverter 12, and the battery 13 is controlled in cooperation with, for example, individually provided ECUs (Electric Control Units) communicating with each other by CAN (Control Area Network). However, in the present embodiment, each configuration will be described as being controlled by one control device 10.

The control device 10 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a control program is stored, a working memory such as a RAM (Random Access Memory), and the like. The CPU reads a control program from the ROM, expands it into the RAM, and centrally controls the operations of the motor 11, the inverter 12, and the battery 13 in cooperation with the expanded control program. The control device 10 functions as an ECU (Electronic Control Unit) that controls the electric vehicle 1 in an integrated manner.

The control device 10 performs a travel control process for the electric vehicle 1. In the travel control process, the control device 10 rotates the motor 11 using the electric power supplied from the battery 13 based on the opening degree of the accelerator pedal detected by the accelerator opening degree sensor 18, and corresponds to the opening degree. The drive torque is output. The drive torque output by the motor 11 is transmitted to the drive wheels 16 via the propeller shaft 14 and the differential gear 15, so that the electric vehicle 1 travels.

Further, the control device 10 performs a vehicle weight estimation process for estimating the weight of the electric vehicle 1 based on the driving force calculated from the driving torque obtained from the motor 11 and the acceleration calculated from the vehicle speed sensor 17. The details of the vehicle weight estimation process will be described later.

When the control device 10 requests the motor 11 to be driven, the inverter 12 converts the DC power of the battery 13 into three-phase AC power and supplies it to the motor 11. The battery 13 supplies electric power to the motor 11 via the inverter 12 when the control device 10 requests the motor 11 to be driven.

The vehicle speed sensor 17 detects and outputs the vehicle speed of the electric vehicle 1 based on, for example, the number of rotations of the drive wheels 16.

The accelerator opening sensor 18 detects and outputs the opening degree of the accelerator pedal (hereinafter, may be simply referred to as the opening degree) when the driver of the electric vehicle 1 depresses the accelerator pedal (not shown).

FIG. 2 is a block diagram for explaining the function of the control device 10. As shown in FIG. 2, the control device 10 includes an acceleration calculation unit 101, a motor control unit 102, and a vehicle weight estimation unit 103.

The acceleration calculation unit 101 calculates the acceleration of the electric vehicle 1 based on the vehicle speed obtained from the vehicle speed sensor 17.

The motor control unit 102 controls the rotation of the motor 11 in response to a driver's operation on an operation receiving unit such as an accelerator pedal (not shown) and a request from the vehicle weight estimation unit 103.

The vehicle weight estimation unit 103 estimates the vehicle weight of the electric vehicle 1 by using the acceleration at the timing when the electric vehicle 1 accelerates while the electric vehicle 1 is running.

Hereinafter, the vehicle weight estimation process performed by the control device 10 will be described in detail. FIG. 3 is a flowchart for explaining the vehicle weight estimation process by the control device 10.

In step S1, the control device 10 determines whether or not a depressing operation (acceleration operation) has been performed on the accelerator pedal. This determination may be made based on the speed of change of the opening degree output by the accelerator opening degree sensor 18. If it is determined that there is a stepping operation (step S1: YES), the control device 10 advances the process to step S2, and if not (step S1: NO), the process of step S1 is repeated.

In step S2, the control device 10 determines whether or not the amount of depression in step S1 exceeds the threshold value. If the stepping amount exceeds the threshold value (step S2: YES), the control device 10 advances the process to step S3, and if not (step S2: NO), returns the process to step S1.

In other words, the processes of steps S1 and S2 are processes for determining whether or not the driver of the electric vehicle 1 requires a large acceleration force.

In step S3, the control device 10 calculates a first torque obtained by adding a compensation torque for canceling (compensating) the inertia (moment of inertia) of the electric vehicle 1 to the torque corresponding to the accelerator opening, and the motor control unit. According to 102, a first torque is requested from the motor 11.

The inertia of the electric vehicle 1 corresponds to a running resistance peculiar to the electric vehicle 1, such as a drag resistance (a resistance applied to a drive shaft by a component of a brake). The compensation torque for compensating for this inertia is acquired as a unique value at the time of designing the electric vehicle 1, for example, and is stored in a memory (not shown) of the control device 10. The compensation torque may be acquired by, for example, a simulation, or may be acquired by an experiment in which the empty electric vehicle 1 is actually driven.

By the process of step S3 as described above, the motor 11 outputs the first torque obtained by adding the compensation torque to the torque requested by the driver of the electric vehicle 1 from the depression of the accelerator pedal, and the electric vehicle 1 accelerates.

In step S4, the control device 10 calculates the acceleration at the first time point during acceleration by the motor 11 outputting the first torque by the acceleration calculation unit 101. As a method of calculating the acceleration, for example, a method of calculating based on the rate of change of the vehicle speed detected by the vehicle speed sensor 17 can be adopted.

After that, in step S5, the control device 10 determines whether or not the depression of the accelerator pedal is released based on the output value from the accelerator opening sensor 18. The state in which the depression is released is a state in which the driver of the electric vehicle 1 takes his / her foot off the accelerator pedal, that is, a state in which the opening degree becomes 0. If it is determined that the stepping is released (step S5: YES), the control device 10 advances the process to step S6, and if not (step S5: NO), the process of step S5 is repeated.

In step S6, the control device 10 determines whether or not _{the time T 1} from the depression of the accelerator pedal detected in step S1 to the release of depression of the accelerator pedal detected in step S5 is within the predetermined time T _th. To judge. If it is determined that T ₁ is _{within T th} (step S6: YES), the control device 10 proceeds to step S7, and if not, proceeds to step S9.

When it is determined in step S6 that T ₁ is _{within T th} , in step S7, the control device 10 calculates the acceleration at the second time point during ellipsing after the depression is released by the acceleration calculation unit 101. To do. Then, in step S8, the vehicle weight estimation unit 103 determines the acceleration at the first time point and the drive torque at the first time point (first torque), and the acceleration at the second time point and the drive torque at the second time point. The weight of the electric vehicle 1 is estimated based on the above.

As the vehicle weight estimation method by the vehicle weight estimation unit 103, for example, the following method can be adopted. According to the well-known equation of motion, the following equations (1) and (2) are established for each of the first and second time points.
F ₁ −R = m × a ₁ ... (1)
F _2- R = m × a ₂ ... (2)

In the formula (1), F ₁ is the driving force at the first time point calculated from the driving torque at the first time point (first torque), a ₁ is the acceleration at the first time point, and R is the running resistance of the electric vehicle. m is the weight of the electric vehicle 1. Further, in the equation (2), F ₂ is the driving force at the second time point calculated from the driving torque at the second time point, and a ₂ is the acceleration at the second time point.

From the formula (1) and the formula (2), the weight m is represented by the following formula (3).
m = (F ₁ −F ₂ ) / (a ₁ −a ₂ ) ・ ・ ・ (3)

Since the driving force at the second time point is 0 because the electric vehicle 1 is in an elliptical shape, the weight m is expressed by the following equation (4).
m = F ₁ / (a ₁ −a ₂ ) ・ ・ ・ (4)

The following equation (5) is generally used to calculate the driving force F from the driving torque T.
F = T ・_if / r ・ ・ ・ (5)

In equation (5), _if is the final gear ratio and r is the radius of the drive wheels 17.

On the other hand, _{when it is determined in step S6 that T 1} is _{larger than T th} , the control device 10 discards the acceleration at the first time point acquired in step S4 in step S9. In other words, the control device 10 does not use the acceleration at the first time point for weight estimation. Then, the control device 10 returns the process to step S1.

The processes of steps S1 to S9 described above are repeated in minute time (for example, milliseconds) units, whereby the weight of the electric vehicle 1 is preferably adjusted by the vehicle weight estimation unit 103 of the control device 10. Presumed.

<Action, effect>
As described above, the control device (vehicle weight estimation device) 10 according to the embodiment of the present disclosure is a vehicle weight estimation device that estimates the weight of the electric vehicle 1, and is an accelerator that detects the opening degree of the accelerator pedal. Calculates the acceleration of the opening sensor 18, the motor (drive source) 11 that generates drive torque based on the opening, the motor control unit (drive source control unit) 102 that controls the motor 11, and the electric vehicle 1. It has an acceleration calculation unit 101 and a vehicle weight estimation unit 103 that estimates the weight based on the driving torque and acceleration at two or more time points while the electric vehicle 1 is running, and the motor control unit 102 is used as an accelerator pedal. On the other hand, when a stepping operation is performed in which the opening degree changes by a change amount equal to or greater than the threshold value, the first torque obtained by adding the compensation torque for compensating the inertial moment of the electric vehicle 1 to the torque corresponding to the opening degree is applied to the motor 11. The vehicle weight estimation unit 103 generates and uses the drive torque and the acceleration at the first time point during the acceleration of the electric vehicle 1 by the first torque for the weight estimation.

Further, in the control device (vehicle weight estimation device) 10 according to the embodiment of the present disclosure, the vehicle weight estimation unit 103 performs a stepping operation in addition to the drive torque and acceleration at the first time point during acceleration by the first torque. The drive torque and acceleration at the second time point when the vehicle is decelerated or decelerated after being released is used for weight estimation.

With such a configuration, the following effects can be obtained. Conventionally, in an electric vehicle, the driving force generated by the motor is transmitted to the drive wheels without using a driving force transmission device such as a clutch. Therefore, when the weight is estimated from the acceleration and the driving torque at two different time points of the electric vehicle. The acceleration and the drive torque at the two time points are close to each other, and the influence of the error included in detecting the values of the acceleration and the drive torque tends to be large. However, according to the control device (vehicle weight estimation device) 10 according to the embodiment of the present disclosure, the acceleration at the first time point during acceleration is acquired by the first torque to which the compensation torque is added, and the acceleration at the first time point is obtained. a first torque, by performing weight estimation using the acceleration at a second time point in楕行, acceleration a of the acceleration a ₁ and the second point of the first time point as compared with the case without the addition of compensation torque _{The difference from 2} can be increased. Therefore, when weight estimation is performed using the above equation (4) _{, the influence of error due to the close sizes of a 1} and a ₂ can be reduced, and highly accurate weight estimation can be performed. it can.

The first torque generated by the control device 10 in the motor 11 at the first time point is actually larger than the torque requested by the driver (torque according to the opening degree) by the amount of the compensation torque. However, since the compensation torque is added only when the driver depresses the accelerator pedal strongly, it is difficult for the driver to feel a sense of discomfort.

Further, in the control device (vehicle weight estimation device) 10 according to the embodiment of the present disclosure, when the time from the first time point to the second time point is longer than the predetermined time, the vehicle weight estimation unit 103 is at the first time point. Acceleration and first torque should not be used to estimate the weight. This is because, for example, when the distance between the first time point and the second time point when the stepping is released and the electric vehicle 1 is in the elliptical shape is widened, the slope of the road on which the electric vehicle 1 travels changes. This is because the value of the traveling resistance R appearing in (1) and (2) changes, making it difficult to perform accurate weight estimation. By such a process, the weight is estimated only when the first time point and the second time point are close to each other to some extent or more, so that the weight estimation can always be performed with high accuracy.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be appropriately modified and implemented without departing from the spirit of the present disclosure.

The present disclosure can be applied to a vehicle weight estimation device that suitably estimates the weight of a vehicle.

1 Electric vehicle 10 Control device 101 Acceleration calculation unit 102 Motor control unit 103 Vehicle weight estimation unit 11 Motor 12 Inverter 13 Battery 14 Propeller shaft 15 Differential gear 16 Drive wheel 17 Vehicle speed sensor 18 Accelerator opening sensor

Claims (5)

It is a vehicle weight estimation device that estimates the weight of a vehicle.
An accelerator opening sensor that detects the opening of the accelerator pedal,
A drive source that generates drive torque based on the opening degree,
A drive source control unit that controls the drive source,
An acceleration calculation unit that calculates the acceleration of the vehicle,
A vehicle weight estimation unit that estimates the weight based on the drive torque and the acceleration at two or more time points while the vehicle is running.
Have,
The drive source control unit corresponds to the opening degree by providing compensation torque for compensating for the moment of inertia of the vehicle when a stepping operation is performed on the accelerator pedal in which the opening degree changes by a change amount equal to or greater than a threshold value. A first torque added to the generated torque is generated in the drive source to generate the first torque.
The vehicle weight estimation unit uses the drive torque and the acceleration at the first time point during acceleration of the vehicle by the first torque to estimate the weight.
Vehicle weight estimation device. In addition to the drive torque and the acceleration at the first time point during acceleration by the first torque, the vehicle weight estimation unit is said to have said that at the second time point when the stepping operation is released and the vehicle is elliptical or decelerating. The drive torque and the acceleration are used to estimate the weight.
The vehicle weight estimation device according to claim 1. When the time from the first time point to the second time point is longer than a predetermined time, the vehicle weight estimation unit prevents the acceleration and the first torque at the first time point from being used for estimating the weight.
The vehicle weight estimation device according to claim 2. The drive source is an electric motor.
The vehicle weight estimation device according to claim 1 or 2. The vehicle weight estimation device according to any one of claims 1 to 4.
vehicle.

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