JP3989201B2 - Braking device for connected vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a braking device for a connected vehicle including a tow vehicle (tractor) and a towed vehicle (trailer) to be pulled by the tow vehicle. The present invention relates to vehicle attitude control or rollover prevention control. The present invention relates to attitude control for preventing a phenomenon that a towed vehicle rolls over (rollover) due to excessive vehicle acceleration or excessive lateral acceleration caused by steering.
[0002]
[Prior art]
When the yaw rate or roll angle near the center of gravity of the vehicle is detected, and this exceeds a preset value, some wheels are automatically controlled to be in a braking state regardless of driving operation to prevent rollover. Devices that perform attitude control are known. Although it is theoretically possible to equip such a rollover prevention device in a connected vehicle, it is not practical. In other words, it is possible to equip a tow vehicle with a sensor for observing the yaw rate or roll angle, but all towed vehicles are equipped with a sensor for observing the yaw rate or roll angle, and the towed vehicle is accidentally It is practically difficult to deploy a sensor that is suitable for a towing vehicle that is connected to the vehicle.
[0003]
In general, a connected vehicle is mainly used as a freight transportation vehicle. When the connected vehicle arrives at the loading / unloading position, the connection vehicle is disconnected and only the towed vehicle is left at that position. Is set to start by towing another towed vehicle already loaded and unloaded at that position. When such an operation is performed, the effective operation rate of the driver and the expensive tow vehicle is improved as compared with the case where the specific tow vehicle is left connected to the specific tow vehicle. Therefore, in one company or group, the standards of tow vehicles and towed vehicles are determined and operated so that any towed vehicle can be connected to one towed vehicle and operated.
[0004]
As described above, it is not desirable from a vehicle operation mode to provide a large-scale equipment such as providing some kind of sensor for preventing the rollover of the towed vehicle, but to perform a rollover prevention control of the connected vehicle. In addition, a technique has been disclosed in which a towed vehicle is provided with a minimum sensor such as a wheel rotation sensor, and the state of the towed vehicle is estimated using this to perform a rollover prevention control (Japanese Patent Laid-Open No. 9-323632). ). In the future, it will be widely used to equip towed vehicles with ABS (Antilock Breaking System). Therefore, it is thought that many towed vehicles will be equipped with wheel rotation sensors that serve as ABS control inputs. In that sense, the technique disclosed in the above publication is an excellent technique.
[0005]
However, although this technology is also a small member, a towed vehicle is equipped with a specific sensor, and an electric signal connection means for transmitting the sensor output from the towed vehicle to the towed vehicle is required. In general, since the life of the towed vehicle is longer than that of the towed vehicle, it takes a considerably long time for all of the towed vehicles to be equipped with ABS. Moreover, even if the vehicle manufacturers are different or the model year is changed sequentially, it is unlikely that the ABS of all towed vehicles will be unified to the same standard. Therefore, as long as the above technology is adopted, in the future, the towed vehicles that can be connected to one towed vehicle will be limited. Since this is inconvenient for the operation of the vehicle as described above, it is considered that the technology disclosed in the above publication cannot be widely accepted by users such as many freight carriers.
[0006]
In principle, the applicant of the present invention observes the lateral acceleration with a sensor provided on the towed vehicle side even if the towed vehicle is not equipped with a sensor or the like, and is stable against a towed vehicle not equipped with ABS. Has filed a patent application for an invention relating to a braking control apparatus for automatically controlling braking without reducing the above and avoiding a rollover accident (Japanese Patent Laid-Open No. 2001-58563, hereinafter referred to as “prior application”). The invention of the prior application estimates the state of the towed vehicle using the lateral acceleration sensor provided on the towed vehicle and the operation angle of the steered vehicle steering wheel as input, and when the towed vehicle is likely to roll over, This is a device for controlling the towed vehicle to be in a braking state automatically without any operation.
[0007]
[Problems to be solved by the invention]
In the process of repeating a number of tests for this prior invention, automatic braking control for preventing the towed vehicle from rolling over tends to operate slightly earlier on the safe side, and some drivers are not satisfied with this. I found out that there was a case. This is because the towed vehicle does not roll over in consideration of the case where the load of the towed vehicle is large and the load of the towed vehicle is biased to either the left or right in the apparatus adopting the above-mentioned prior invention. As described above, the control threshold is set somewhat strictly on the safe side. As a result, it was found that even when the load is small and there is no bias and the possibility of rollover is small, automatic braking control is executed according to this control threshold, which appears to be dissatisfied with the driver.
[0008]
The inventor of the present application tried to cope with various measures by changing the operation threshold of lateral acceleration and its detection sensitivity as a countermeasure, but a satisfactory result could not always be obtained only by changing the threshold or sensitivity. In other words, considering the dissatisfaction of some drivers, if the movement threshold is set to a large value of lateral acceleration, there is a possibility that braking control may not be executed when the vehicle posture cannot be controlled under various conditions. I found out.
[0009]
Japanese Patent Application Laid-Open No. 10-329682 describes that braking control is automatically executed using outputs of a lateral acceleration sensor and a load sensor or an air suspension air pressure sensor. The target is not a connected vehicle. In the invention disclosed in this publication, there is no idea that the load of the towed vehicle is observed on the towed vehicle side and used for control. Japanese Laid-Open Patent Publication No. 2000-43705 describes an automatic reduction device for a connected vehicle, but this publication does not disclose the concept of observing the weight of a towed vehicle on the towed vehicle side.
[0010]
The present invention has been made in such a background, and an object of the present invention is to provide a braking control device that performs automatic braking control in consideration of the size of the load of the towed vehicle. The present invention provides a braking control device in which the state of loading of a towed vehicle is taken to rationally set a threshold value for braking control, and automatic braking control is not performed in an area where braking control for preventing rollover is unnecessary. The purpose is to provide. An object of this invention is to provide the apparatus which can respond to dissatisfaction that some drivers may perform braking control early. The present invention eliminates the need to provide a sensor and other equipment for preventing rollover on the towed vehicle side, and does not limit the towed vehicle to which one towed vehicle can be connected. The purpose is to provide.
[0011]
[Means for Solving the Problems]
The greatest difference between the invention of the prior application of the present invention is that the approximate load value of the towed vehicle is observed by the air pressure of the air suspension provided on the rear shaft of the towed vehicle, and this is used as an automatic braking control parameter. There is a place to do. This is to observe the load of the towed vehicle with a device provided on the towed vehicle side, and the towed vehicle is not provided with a sensor or the like for load observation. With this configuration, the braking control threshold value can be set appropriately, and braking control in an area where braking control is not necessary can be prohibited.
[0012]
That is, according to the present invention, when the vehicle speed exceeds a predetermined value, the lateral acceleration detection means has a lateral acceleration exceeding the first threshold for a predetermined time (including a case where the predetermined time is extremely short). In the brake device for a connected vehicle, the control unit is provided with a control unit that automatically sets the brake unit of the towed vehicle to a braking state even when no braking operation is performed. More preferably, according to the air pressure of the air suspension installed on the rear shaft of the towing vehicle that shares the load of the towed vehicle in a state where the air suspension is connected to the towing vehicle, A means for changing the setting of the first threshold according to the combination of the magnitudes of the lateral accelerations is included.
[0013]
In a state where the towed vehicle is connected to the towing vehicle, a part of the load of the towed vehicle is applied to the towing vehicle via the coupler. The inventor of the present application examined how much of the load of the towed vehicle is applied to the rear shaft of the towed vehicle using a model. It is a form of cargo that can actually be carried, and it is assumed that the cargo is extremely large and packed in an extremely small size. When this loaded cargo is loaded on the foremost part of the towed vehicle, the entire load of this loaded cargo is applied to the rear axle of the towed vehicle. The load of the part will be applied to the rear axle of the towing vehicle, and the other part will be applied to the axle of the towed vehicle. In this way, when a part of the load is applied to the axle of the towed vehicle, a detection error is generated only by detecting the load applied to the towed vehicle axle. The total vehicle weight was estimated using the air pressure of the vehicle, and this was used as the control threshold for setting control. This detection error will be described in detail by providing an example in the section of the embodiment of the invention described later.
[0014]
When the rear shaft of the towing vehicle is a single shaft, one air suspension is provided on the left and right wheels, or when the rear shaft is a two shafts, two rear wheels are provided on the left and right wheels. Since this load is received by the air suspension, the load of the towed vehicle can be observed by the average value of the air pressure of these air suspensions. It is possible to set an area where the braking control is unnecessary from the average value of the air pressure. In this area, even if the lateral acceleration exceeds the first threshold, the braking control is not executed. I made it.
[0015]
The control means effectively activates the engine brake of the towing vehicle when the lateral acceleration detection means detects a lateral acceleration exceeding a second threshold value set to a value lower than the first threshold value. It is desirable to have a configuration that includes a means for making it happen. This is an auxiliary safety device. The driver has the inherent responsibility and duty to operate the vehicle with sufficient safety considerations below the safe speed so that the vehicle will not roll over. When steering at a large angle, it is necessary to consider such as reducing the vehicle speed accordingly. However, if an automatic braking control device such as that of the present invention is installed and experienced to work effectively, the driver may depend on the operation of this device. In other words, if it is dangerous, it may be decelerated by automatic control of the device, and a large steering angle may be operated at a high speed. For this reason, as described above, the threshold value of the lateral acceleration at which the braking control is executed is set high, and when the lateral acceleration approaches the threshold value at a predetermined vehicle speed or higher, the towed vehicle is put into a braking state. Although it is not controlled, the engine brake on the towing vehicle side is automatically controlled to be in an operating state, and is controlled to the safe side so that it is not accelerated further or decelerated slowly.
[0016]
The actual design is a combination of service brake control and engine brake control, which depends on the combination of the air suspension air pressure magnitude and the lateral acceleration magnitude. It is desirable that the threshold value be changed. Specific examples of combinations will be described in detail later with reference to the drawings.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a conceptual diagram of a vehicle connected to a first embodiment of the present invention, FIG. 2 is a block diagram of an electric system of the apparatus according to the present invention, FIG. FIG. 5 is a flowchart showing the main part of the control logic set in the control circuit of the apparatus of this embodiment. FIG. 5 is an explanatory diagram for setting an area where the tow vehicle is light and control is unnecessary.
[0018]
In this embodiment, the tow vehicle 1 and the towed vehicle 2 are connected by a coupler 3 that can rotate around a vertical axis. The load of the towed vehicle 2 is supported by the rear shaft of the towed vehicle 2 and the rear shaft of the towed vehicle 1. The control circuit 11 and the lateral acceleration sensor 12 of the present invention are installed behind the driver's seat of the tow vehicle. The lateral acceleration sensor 12 is mounted so as to detect horizontal acceleration (L, R) in the horizontal direction on a plane perpendicular to the traveling direction of the vehicle. The output of the lateral acceleration sensor 12 is taken into the control circuit 11 via the input / output circuit 13. Rotation sensors 15 to 18 are respectively provided on the left and right wheels of the front and rear two axes of the towing vehicle, and the output is taken into the control circuit 11 via the input / output circuit 20. In the apparatus of the present invention, the air pressure sensors 5 detect the air pressures of the air suspensions provided on the left and right wheels of the rear axle of the towing vehicle as electric signals, and take them into the control circuit 11 via the input / output circuit 13. It is configured.
[0019]
The control circuit 11 is a program control circuit (computer). A logical operation is executed according to software set in advance using the input information, and a control output is sent to the control valve and other hardware. In the above prior invention, the steering angle of the steered wheel is detected and taken into the control circuit. However, this may not always be necessary by detecting the load of the towed vehicle. However, the information system about the steering angle of the steered wheels is omitted.
[0020]
The output of the control circuit 11 is configured to control the three relay valves 21 to 23 through the input / output circuits 31 to 33, respectively. The braking pressure of the left and right front wheels (F _r L, F _r R) of the towing vehicle 1 is supplied from the relay valve 21. From the relay valve 22, the braking pressure of the left and right rear wheels (R _r L, R _r R) of the towing vehicle 1 is supplied. From the relay valve 23, the braking pressure of the rear biaxial wheel (TR) of the towed vehicle 2 is supplied via the pipeline 25. The control output of the control circuit 11 is connected to an engine control circuit (not shown) via the input / output circuit 34. This is a configuration for temporarily reducing the flow rate of fuel supplied to the engine of the towing vehicle to control the engine of the towing vehicle to the engine brake state.
[0021]
Here, the setting of the control threshold, which is a feature of the present invention, will be described. The horizontal axis of FIG. 3 shows the air pressure of the air suspension. The vertical axis represents the value of the lateral acceleration of the tow vehicle detected by the lateral acceleration sensor 12. A solid line in the figure represents a braking threshold value for automatically controlling the towed vehicle (and the towed vehicle) to the braking state by the braking control device. An alternate long and short dash line is an engine brake control threshold value for controlling the engine of the tow vehicle to an engine brake state. This threshold is characterized in that the lateral acceleration is set stepwise corresponding to the air suspension air pressure. That is, when the vehicle speed is equal to or higher than the predetermined value (V ₁ ) and the air suspension air pressure is equal to or higher than P ₂ , that is, when the load of the towed vehicle is large, the lateral acceleration is relatively small value G _y3 and When the lateral acceleration becomes a slightly larger value G _y2 , air pressure is sent to the brake system of the towed vehicle to automatically bring the towed vehicle into a braking state and decelerate the vehicle.
[0022]
Is slightly smaller load of the towed vehicle, when the air pressure of the air suspension is between P ₁ and P _2, the operation threshold value for the transverse acceleration of the engine brake becomes slightly large value G _y2, the operation threshold of the brake control A larger value _Gy1 is set. When the load of the towed vehicle is smaller and the air suspension air pressure is P ₁ or less, the control threshold for the lateral acceleration is set to infinity, assuming that automatic braking control is unnecessary.
[0023]
The specific value for the lateral acceleration and the value of the air suspension air pressure are set to optimum values according to the respective vehicle specifications. As an example, when the towed vehicle is a tank truck with a maximum loading capacity of 17 tons, the air pressure P _{1 of the} air suspension is 180 kPa (kilopascal), the P ₂ is 280 kPa, and the lateral acceleration G _y3 is 0.35 G. _y2 is 0.40G, the G _y1 is 0.45G. G is the gravitational acceleration.
[0024]
FIG. 4 is a diagram showing how the detected value based on the air pressure of the air suspension changes corresponding to the center-of-gravity variation of the towed vehicle depending on the loading position. The load assumed here is an extreme form of load that can actually occur, as described in the section of means for solving the above problems. That is, this load has a very large mass and is packaged in a very small size. The horizontal axis shows the position of the center of gravity when this load is mounted closest to the towed vehicle as the reference position (0%), and the change in the position of the center of gravity when the load moves to the rear of the towed vehicle. Displayed as a percentage of the total length of the towing vehicle. The vertical axis represents the total weight of the tow vehicle (tractor) and the towed vehicle (trailer). Since the total weight does not change even when the loading position is moved, the weight line is parallel to the horizontal axis. However, the quantity detected by the device of the present invention is not the tow truck weight or the quantity itself proportional to the weight, but the air suspension air pressure of the rear axle of the towing truck.
[0025]
If this air pressure is the air pressure P ₁ described in FIG. 3 above, the total weight is 12 tons when the load is loaded most forward, but the total weight when the load is loaded most rear is The weight is 17 tons. Assuming that the air pressure is P ₂ described above, the total weight is 15 tons at the frontmost position, and the total weight is 24 tons at the rearmost position. When the load becomes rearward in FIG. 4, errors indicated by diagonal lines are generated, but the curves P ₁ and P ₂ are approximated to the gross vehicle weight on the assumption that these errors do not greatly affect the control. We decided to use it as an amount proportional to That is, in the apparatus of the present invention, the possibility that an error of the level indicated by the hatching in FIG. 4 may occur due to the loading position in the towed vehicle, and the value detected by the air suspension air pressure is calculated as the total vehicle weight. This value is used for setting a control threshold value.
[0026]
FIG. 5 is a flowchart showing the main part of the control operation of the apparatus of this embodiment. When the control circuit 11 is activated, each input information is taken in sequentially. This input information includes the output information of the air pressure sensor of the air suspension. When the vehicle speed exceeds a predetermined value V ₁ , the output of the lateral acceleration sensor 12 is taken. Whether the output of the lateral acceleration sensor 12 exceeds a threshold value (second threshold value) for controlling engine braking, braking control is performed. Whether the threshold value (second threshold value) has been exceeded is identified. If the respective threshold values are exceeded, engine braking and / or braking control is executed. That is, as described with reference to FIG. 3, when the engine brake control threshold is exceeded, control is performed so that the engine brake is activated and the vehicle speed does not increase further, or the vehicle speed is gradually reduced. When the output of the lateral acceleration sensor 12 exceeds the braking control threshold, the towed vehicle braking control is automatically executed. In both the engine brake control and the brake control, the engine brake control and / or the brake control are canceled when the lateral acceleration falls below the set control threshold value.
[0027]
【The invention's effect】
Thus, the apparatus of the present invention can execute automatic braking control in consideration of the size of the load of the towed vehicle. Accordingly, the braking control threshold is set rationally, and automatic braking control is not executed in an area where braking control for preventing rollover is unnecessary. As a result, dissatisfaction that some drivers may execute the braking control early is eliminated. The apparatus of the present invention does not require any sensors or other equipment for preventing rollover on the towed vehicle side, and does not limit the towed vehicle to which one towed vehicle can be connected.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a connected vehicle for carrying out the present invention.
FIG. 2 is a block diagram of an apparatus according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating threshold values for braking control and engine brake control of the embodiment device of the present invention.
FIG. 4 is a diagram for explaining a detection error depending on a position of a load loaded on a towed vehicle.
FIG. 5 is a main part control flowchart of the apparatus according to the embodiment of the present invention;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Towing vehicle 2 Towed vehicle 3 Connector 5 Air pressure sensor 11 Control circuit 12 Lateral acceleration sensor 13 Input / output circuit 15-18 Rotation sensor 19 Steering angle sensor 20 Input / output circuit 21-23 Relay valve 25 Braking pressure of towed vehicle Piping 31-33 Input / output circuit 34 Input / output circuit

Claims (3)

The lateral acceleration detection means and the lateral acceleration detection means when the vehicle speed exceeds a predetermined value, when the lateral acceleration exceeding the first threshold continues for a predetermined time or more, even if there is no braking driving operation, In a brake device for a connected vehicle provided with a control means for automatically bringing a braking means into a braking state on a tow vehicle,
The control means includes a towed vehicle according to the air pressure of the air suspension provided on the rear shaft of the towed vehicle that shares the load of the towed vehicle with the towed vehicle connected to the towed vehicle. The weight of the towed vehicle is estimated with an approximate value that allows an error in the load applied to the rear shaft of the towed vehicle depending on the position of the loaded cargo, and according to the estimated weight of the vehicle, the towed vehicle is in the lightest region. A braking device for a connected vehicle, comprising means for deactivating vehicle braking control and stepwise changing the first threshold value to a lower value as the weight increases.   The control means effectively activates the engine brake of the tow vehicle when the lateral acceleration detection means detects a lateral acceleration exceeding a second threshold value set to a value lower than the first threshold value. The braking device for a connected vehicle according to claim 1, further comprising means.   The braking device for a connected vehicle according to claim 2, further comprising means for changing the first threshold value and the second threshold value in accordance with a combination of a magnitude of air pressure of the air suspension and a magnitude of the lateral acceleration.

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