JP7654325B2 - Weight Estimation Device - Google Patents

Description

The present invention relates to a weight estimation device mounted on a vehicle.

Recently, automobiles and other vehicles have been equipped with AEBS (Advanced Emergency Braking System).

In AEBS, a stereo camera captures an image of the front of the vehicle (host vehicle), and when an obstacle is detected in front of the vehicle from the captured image, the distance and relative speed between the obstacle and the vehicle are detected. Then, if there is a high possibility of a collision between the vehicle and the obstacle, the braking distance required to reach a target position in front of the obstacle is calculated from the distance and relative speed between the vehicle and the obstacle, and the timing for applying the brakes, as well as the deceleration and jerk at that timing, are set so that the vehicle can be stopped within that braking distance, and the brakes are controlled based on these.

JP 2013-154813 A

The braking distance of a vehicle on a road that is wet from rain depends on the total weight of the vehicle, which varies depending on factors such as the number of passengers in the vehicle. AEBS is programmed to control the brakes on the assumption that the vehicle will be traveling at its total vehicle weight (vehicle weight plus the number of passengers x 55 kg), prioritizing sufficient deceleration even when the number of passengers is at its maximum. Therefore, when the actual total weight of the vehicle is light, such as when the number of passengers is less than the number of passengers, the vehicle may stop at a position significantly shorter than the target position. If the timing of braking operation is determined taking into account the actual total weight of the vehicle, it is possible to stop the vehicle at the target position, but as a prerequisite, the actual total weight of the vehicle must be estimated.

The object of the present invention is to provide a weight estimation device that can estimate the actual total weight of a vehicle.

To achieve the above object, the weight estimation device of the present invention includes a camera arranged in a position capable of capturing an image of all seats in the vehicle cabin, a total weight estimation unit that estimates the total weight of people in the vehicle cabin from an image captured by the camera, and a total weight estimation unit that adds the vehicle weight of the vehicle and the total weight estimated by the total weight estimation unit, and estimates the sum as the actual total weight of the vehicle.

According to this configuration, a camera is placed inside the vehicle cabin in a position that allows it to capture images of all the seats. The total weight of the people in the cabin is estimated from the images captured by the camera. For example, the people in the cabin are identified by analyzing the images captured by the camera, and the physique of each identified person (the area they occupy) is recognized. The total weight of the people in the cabin is estimated by adding up the weights estimated from each person's physique. The estimated total weight is then added to the known vehicle weight, and the added value is estimated to be the actual total weight of the vehicle.

This makes it possible to estimate the vehicle's actual total weight even if the number of passengers in the vehicle changes or the number of passengers increases or decreases.

Since the actual total weight of the vehicle can be estimated, by incorporating a weight estimation device into the AEBS, the timing of brake application, etc. can be determined taking into account the actual total weight of the vehicle, allowing the vehicle to be stopped accurately at the target position.

There are no restrictions on the placement of the camera as long as it can capture images of all seats, but it is preferable that the camera be attached to the ceiling of the vehicle interior and placed in a position between the front and rear seats. In this position, the camera can capture the entire people sitting in all seats, making it possible to accurately recognize each person's physique and accurately estimate their weight from each person's physique.

The present invention allows the actual total weight of a vehicle to be estimated.

1 is a block diagram showing a configuration of a collision damage mitigation brake system incorporating a weight estimation device according to an embodiment of the present invention. FIG. 1 is a plan view of a vehicle equipped with a collision mitigation braking system, showing the interior of the vehicle through a transparent view.

The following describes in detail an embodiment of the present invention with reference to the attached drawings.

<Collision mitigation brake system>
Fig. 1 is a block diagram showing the configuration of a collision damage mitigation brake system 1 incorporating a weight estimation device according to an embodiment of the present invention. Fig. 2 is a plan view of a vehicle 2 equipped with the collision damage mitigation brake system 1, showing the interior of a passenger compartment 3 in a see-through manner.

The Autonomous Emergency Braking System (AEBS) 1 is a system for avoiding a collision between the vehicle 2 and an obstacle such as a vehicle ahead or for reducing damage caused by the collision. It has an alarm function that activates an alarm to prompt the driver to take action to avoid the collision before the automatic brake is activated, and a brake function that decelerates the vehicle 2 by applying the automatic brake to avoid the collision and reduce damage caused by the collision.

The collision damage mitigation brake system 1 includes a human detection camera 4 that captures images of the interior 3 of the vehicle 2 and a stereo camera 5 that captures images of the area in front of the vehicle 2.

<Human detection camera>
The human detection camera 4 is attached to a ceiling 6 in the passenger compartment 3 of the vehicle 2, and is disposed in a position between a front seat 7 and a rear seat 8. The human detection camera 4 includes a camera body 11 and a microcomputer (microcontroller) 12.

The camera body 11 includes a lens 13 and an image sensor 14, with the lens 13 facing downward. The angle of view (field of view) of the lens 13 is, for example, within the range of 120° to 160°, and all of the seats in the front seats 7 and rear seats 8 are included in the field of view. The image sensor 14 captures the field of view of the lens 13 via the lens 13.

Image data captured by the image sensor 14 is input to the microcomputer 12. The microcomputer 12 essentially includes a total weight estimation unit 15 as a functional processing unit.

The total weight estimation unit 15 estimates the total weight of the people riding in the vehicle cabin 3 from the image captured by the camera body 11 (image data captured by the image sensor 14). Specifically, the people riding in the vehicle cabin 3 are identified by analyzing the image captured by the camera body 11. Then, the physique of each identified person (the area they occupy) is recognized, their weight is estimated from their physique, and the total weight of the people riding in the vehicle cabin 3 is estimated by adding up the estimated weights of each person.

<Stereo camera>
The stereo camera 5 is provided in the passenger compartment 3 of the vehicle 2, and is disposed in front of the rearview mirror facing the upper part of the windshield 9 to capture images of the area ahead of the vehicle 2. The stereo camera 5 includes a pair of left and right camera bodies 21L, 21R and a microcomputer 22.

The camera bodies 21L, 21R are arranged at a distance from each other in the left-right direction, with their respective lenses 24L, 24R facing the windshield 9. The left camera body 21L is equipped with an imaging element (imager, image sensor) 25L that captures the field of view of the lens 24L through the lens 24L. The right camera body 21R is equipped with an imaging element 25R that captures the field of view of the lens 24R through the lens 24R. The left and right lenses 24L, 24R have the same angle of view (field of view), for example, within the range of 120° to 160°.

Image data captured by the image sensors 25L and 25R is input to the microcomputer 22. The microcomputer 22 essentially includes a recognition unit 26, a judgment unit 27, and an operation unit 28 as functional processing units.

The recognition unit 26 recognizes an obstacle present in front of the vehicle 2 from a pair of image data input from the image sensors 25L and 25R. The recognition unit 26 then extracts a target pixel corresponding to the obstacle from each image captured by the image sensors 25L and 25R, detects the amount of deviation in the position of the target pixel between the pair of images, and calculates the distance from the vehicle 2 to the obstacle using the principle of triangulation.

The determination unit 27 determines the possibility of a collision between the vehicle 2 and an obstacle based on the distance and relative speed between the vehicle 2 and the obstacle, and if the possibility of a collision is high, sets the timing for automatic braking to occur and the deceleration and jerk (jerk) of the vehicle 2 at that timing.

More specifically, the vehicle 2 is equipped with a vehicle stability control device 31. The vehicle stability control device 31 is an ECU (Electronic Control Unit) equipped with a microcomputer, and is connected to the microcomputer 22 of the stereo camera 5 and other ECUs so as to enable two-way communication using a CAN (Controller Area Network) communication protocol. A vehicle speed sensor 32 that detects the vehicle speed of the vehicle 2 is connected to the vehicle stability control device 31. The vehicle speed sensor 32 outputs a pulse signal synchronized with the rotation of a rotating body that rotates as the vehicle 2 travels as a detection signal, and the vehicle stability control device 31 obtains the frequency of the detection signal (pulse signal) from the detection signal of the vehicle speed sensor 32 and converts the frequency into vehicle speed. The vehicle speed calculated by the vehicle stability control device 31 is used for control by the vehicle stability control device 31 and is also transmitted to the microcomputer 22 of the stereo camera 5.

The determination unit 27 calculates the relative speed between the vehicle 2 and the obstacle by calculating the change over time in the distance from the vehicle 2 to the obstacle recognized by the recognition unit 26. The determination unit 27 then calculates the time to collision (TTC) by dividing the distance from the vehicle 2 to the obstacle by the relative speed between the vehicle 2 and the obstacle. If the collision prediction time is less than a predetermined warning criterion, the determination unit 27 determines that there is a possibility of a collision between the vehicle 2 and the obstacle, and activates a warning to prompt the driver to take action (brake operation, steering operation) to avoid the collision. If the collision prediction time falls below a braking criterion that is shorter than the warning criterion, the determination unit 27 determines that there is a very high possibility of a collision between the vehicle 2 and the obstacle, and decides to activate the automatic brake to avoid the collision and reduce the damage caused by the collision.

The total weight estimated by the function of the total weight estimation unit 15 is input directly or via a CAN communication network from the microcomputer 12 of the human detection camera 4 to the microcomputer 22 of the stereo camera 5. When the total weight is input from the microcomputer 22 of the stereo camera 5 to the microcomputer 12 of the human detection camera 4, the judgment unit 27 calculates the actual total weight of the vehicle 2 by adding the total weight to the vehicle weight of the vehicle 2. When it is decided to activate the automatic brake, the judgment unit 27 calculates the braking distance required to reach the target position in front of the obstacle from the distance from the vehicle 2 to the obstacle, the relative speed between the vehicle 2 and the obstacle, and the actual total weight of the vehicle 2, and sets the timing to activate the automatic brake as well as the deceleration and jerk at that timing so that the vehicle 2 can be stopped within that braking distance.

The operation unit 28 outputs an automatic brake control command so that the automatic brake operates at the operation timing set by the judgment unit 27 and the deceleration and jerk set by the judgment unit 27 are obtained.

The vehicle 2 employs a hydraulic brake system. In addition to the brake actuator 41, the brake system includes a brake pedal, a brake booster, a master cylinder, and brakes provided on each wheel. The brake pedal is located in a position that is convenient for the driver in the driver's seat to step on it with his right foot. When the brake pedal is stepped on, the force input to the brake pedal is transmitted to the brake booster. The brake booster uses the negative pressure generated in the engine's intake system, and the brake pedal force is amplified by the pressure difference between the negative pressure and atmospheric pressure. The force amplified by the brake booster is transmitted from the brake booster to the master cylinder, and hydraulic pressure corresponding to that force is generated from the master cylinder. The hydraulic pressure of the master cylinder is transmitted to the brake actuator 41, and hydraulic pressure is supplied from the brake actuator 41 to the wheel cylinders of the brakes provided on each wheel, and the hydraulic pressure causes each brake to apply a braking force to the wheel. The brake actuator 41 also has an electric pump built in, and when the automatic brake is activated, the electric pump is driven by power from the battery and the hydraulic pressure generated by the electric pump is supplied to each wheel cylinder.

<Vehicle stability control system>
The vehicle stability control device 31 controls a brake actuator 41 included in the brake system of the vehicle 2 and adjusts the braking force applied to each wheel so that the posture of the vehicle 2 is kept stable when braking or turning the vehicle 2. Furthermore, the vehicle stability control device 31 controls the brake actuator 41 according to an automatic brake control command transmitted from the microcomputer 22 so that the automatic brake is activated at the activation timing set by the microcomputer 22 (determination unit 27) and the deceleration and jerk set by the microcomputer 22 are obtained.

<Action and effect>
As described above, the human detection camera 4 is disposed in a position in the passenger compartment 3 of the vehicle 2 where it can capture images of all the seats. The total weight of the people riding in the passenger compartment 3 is estimated from the images captured by the human detection camera 4. The estimated total weight is then added to the known weight of the vehicle 2, and the added value is estimated to be the actual total weight of the vehicle 2. This makes it possible to estimate the actual total weight of the vehicle 2 even if the people riding in the passenger compartment 3 of the vehicle 2 are replaced or the number of passengers increases or decreases.

Because the actual total weight of vehicle 2 can be estimated, the collision damage mitigation brake system 1 can determine the timing of brake activation, etc., taking into account the actual total weight of vehicle 2, and can stop vehicle 2 at the target position with high accuracy.

The human detection camera 4 is attached to the ceiling of the vehicle interior 3 and is positioned between the front and rear seats inside the vehicle interior 3. This positioning allows the human detection camera 4 to capture the entire people seated in all seats, so that each person's physique can be accurately recognized and their weight can be accurately estimated from their physique.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, the total body weight estimated by the microcomputer 12 of the human detection camera 4 may be used for an adaptive cruise control (ACC) function that causes the vehicle 2 to follow the vehicle ahead.

In addition, when the stereo camera 5 is installed to capture the rear of the vehicle 2, the total body weight estimated by the microcomputer 12 of the human detection camera 4 can be used to set the timing of automatic braking to avoid a collision between the vehicle 2 and an obstacle behind it or to reduce damage caused by the collision, as well as the deceleration and jerk of the vehicle 2 at that timing.

The actual total weight of the vehicle 2 is estimated by adding the vehicle weight of the vehicle 2 to the total weight of the people riding in the passenger compartment 3. However, in order to increase the accuracy of the estimation of the actual total weight of the vehicle 2, objects brought into the passenger compartment 3, such as luggage, child seats, wheelchairs, bicycles, etc., may be identified from the image captured by the human detection camera 4, the weight of each object may be estimated, and the sum of the estimated weights of each object may be added to the sum of the vehicle weight of the vehicle 2 and the total weight of the people riding in the passenger compartment 3, thereby estimating the actual total weight of the vehicle 2.

To improve the accuracy of estimating the total weight of people riding in the passenger compartment 3, a weight sensor may be provided on each seat, and the weight of each person detected by the weight sensor may be compared with the weight of each person estimated from an image captured by the human detection camera 4, and the median value within the overlapping range (AND range) may be estimated as the weight of each person, for example.

In addition, the amount of seat belt extension for each seat is detected, and the weight of each person estimated from the amount of seat belt extension is compared with the weight of each person estimated from the image captured by the human detection camera 4, and, for example, the median value within their overlapping range (AND range) is estimated to be the weight of each person.

In the above embodiment, the actual total weight of the vehicle 2 is estimated by the microcomputer 22 (determination unit 27) of the stereo camera 5, but the actual total weight of the vehicle 2 may be estimated by the microcomputer 12 of the human detection camera 4. In this case, the microcomputer 12 is an example of a total weight estimation unit. Also, image data captured by the human detection camera 4 may be transmitted to the microcomputer 22 of the stereo camera 5, and the total weight of the people riding in the passenger compartment 3 may be estimated by the microcomputer 22 (determination unit 27), and the estimated total weight may be added to the known vehicle weight, and the added value may be estimated as the actual total weight of the vehicle 2. In this case, the microcomputer 22 is an example of a total weight estimation unit and a total weight estimation unit.

In addition, various design modifications can be made to the above-mentioned configuration within the scope of the claims.

2: Vehicle 3: Vehicle compartment 4: Human detection camera (camera)
6: Ceiling 7: Front seat 8: Rear seat 11: Camera body (camera)
12: Microcomputer (weight estimation device, total weight estimation unit)
15: Total weight estimation unit 22: Microcomputer (weight estimation device)
27: Judgment unit (total weight estimation unit)

Claims (2)

A camera disposed in a position capable of photographing all seats in the vehicle interior;
a total weight estimation unit that estimates a total weight of people riding in the vehicle cabin from the image captured by the camera;
a total weight estimation unit that adds the vehicle weight of the vehicle and the total weight estimated by the total weight estimation unit and estimates the sum as an actual total weight of the vehicle;
a weight sensor provided on each seat in the vehicle interior ;
The total weight estimation unit estimates, for each person seated in a seat in the vehicle cabin, the median value within the overlapping range of the weight range detected by the weight sensor and the weight range estimated from the image captured by the camera as the weight of that person, and estimates the total weight by adding up the estimated weights of each person . A camera arranged in a position capable of photographing all seats in the vehicle interior;
a total weight estimation unit that estimates a total weight of people riding in the vehicle cabin from the image captured by the camera;
a total weight estimation unit that adds the vehicle weight of the vehicle and the total weight estimated by the total weight estimation unit and estimates the sum as an actual total weight of the vehicle;
a detection unit provided for each seat in the vehicle interior and detecting a seat belt payout amount,
The total weight estimation unit estimates, for each person seated in a seat in the vehicle cabin, the median value within an overlapping range of the range of weight estimated from the amount of seat belt payout detected by the detection unit and the range of weight estimated from the image captured by the camera as the weight of that person, and estimates the total weight by adding up the estimated weights of each person.

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