JP2017019474A - Travel control apparatus, travel control method, and travel control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel control apparatus capable of improving comfort when automatic braking is disengaged.SOLUTION: A travel control apparatus 100, for use in applying brake force to a vehicle on the basis of target deceleration, includes: a threshold determination part 202 for determining whether the target deceleration is less than a threshold; and a brake instruction part 203 for disengaging, in a case where the target deceleration is determined to be less than the threshold, the brake force so that a ratio of the target deceleration to a period of time for disengaging the brake force is smaller than in the case of the target deceleration being determined to be not less than the threshold.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a travel control device, a travel control method, and a travel control program.

  Conventionally, when an object ahead (for example, a preceding vehicle) is detected by outputting millimeter waves, infrared rays, or other radar waves toward the front of the vehicle, and if it is determined that the detection result satisfies the conditions for executing automatic braking, A travel control device that performs braking is known. Automatic braking refers to an operation in which a traveling control device automatically applies a braking force to a vehicle (without depending on a driver's brake operation).

  In automatic braking, a large deceleration occurs, and a strong inertial force is sometimes applied to the vehicle. If the automatic braking is suddenly released at this time, the inertial force is suddenly lost, which may cause discomfort to the vehicle occupant.

  For example, in Patent Document 1, in order to prevent the driver's steering operation from interfering with automatic braking while ensuring the maximum contact avoidance effect by automatic braking, there is a high possibility that the vehicle will contact an object ahead. Devices have been disclosed that gently release automatic braking.

  It is conceivable to reduce passenger discomfort due to a sudden loss of inertia force by applying a technique for gradually releasing this automatic braking.

JP 2000-142281 A

  However, if the automatic braking is released gently, it takes time to release, so that there is a problem that the return to the vehicle speed before the automatic braking is performed is delayed, giving the driver another discomfort.

  An object of the present disclosure is to provide a travel control device, a travel control method, and a travel control program that can improve comfort when releasing automatic braking.

  The travel control device of the present disclosure is a travel control device that applies a braking force to a vehicle based on a target deceleration, the threshold determination unit that determines whether the target deceleration is less than a threshold, and the target When it is determined that the deceleration is less than the threshold, the ratio of the target deceleration to the time taken to release the braking force is smaller than when the target deceleration is determined not to be less than the threshold. A braking instruction unit for releasing the braking force.

  The travel control method of the present disclosure is a travel control method for applying a braking force to a vehicle based on a target deceleration, the step of determining whether or not the target deceleration is less than a threshold, and the target deceleration When it is determined that is less than the threshold, the braking force is released so that the ratio of the target deceleration to the time taken to release the braking force is smaller than when it is determined that it is not less than the threshold. Steps.

  The travel control program of the present disclosure is a travel control program that applies a braking force to a vehicle based on a target deceleration, the process for determining whether the target deceleration is less than a threshold, and the target deceleration When it is determined that is less than the threshold, the braking force is released so that the ratio of the target deceleration to the time taken to release the braking force is smaller than when it is determined that it is not less than the threshold. And causing the computer to execute the process.

  According to the present disclosure, it is possible to improve comfort when releasing automatic braking.

The block diagram which shows an example of a structure of the vehicle containing the traveling control apparatus which concerns on one embodiment of this indication The block diagram which shows an example of a structure of the traveling control apparatus which concerns on one embodiment of this indication, and its periphery structure The flowchart which shows an example of operation | movement of the traveling control apparatus which concerns on this Embodiment. The figure which shows an example of the target deceleration in this Embodiment

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<Vehicle configuration>
First, a configuration of a vehicle including a travel control device according to an embodiment of the present disclosure will be described.

  FIG. 1 is a block diagram illustrating an example of a configuration of a vehicle including a travel control device according to the present embodiment. It should be noted that here, the illustration and description will be made by paying attention to portions related to the travel control device.

  A vehicle 1 shown in FIG. 1 is, for example, a large vehicle such as a truck equipped with an inline 6-cylinder diesel engine.

  As shown in FIG. 1, a vehicle 1 includes a drive system for driving the vehicle, and includes an engine 3, a clutch 4, a transmission (transmission) 5, a propulsion shaft (propeller shaft) 6, and a differential device (differential gear) 7. , A drive shaft 8 and wheels 9.

  The power of the engine 3 is transmitted to the transmission 5 via the clutch 4, and the power transmitted to the transmission 5 is further transmitted to the wheels 9 via the propulsion shaft 6, the differential device 7, and the drive shaft 8. Communicated. Thereby, the motive power of the engine 3 is transmitted to the wheels 9 and the vehicle 1 travels.

  Moreover, the vehicle 1 has the braking device 40 as a structure of the braking system which stops a vehicle. The braking device 40 includes a foot brake 41 that provides resistance to the wheels 9, a retarder 42 that provides resistance to the propulsion shaft 6, and an auxiliary brake 43 such as an exhaust brake that applies load to the engine. The braking device 40 may include a brake control device (not shown) that controls the foot brake 41, the retarder 42, and the auxiliary brake 43.

  The foot brake 41, the retarder 42, and the auxiliary brake 43 correspond to an example of a brake unit 230 (see FIG. 2) to be described later, and the brake control device (not shown) is a brake control unit 220 (see FIG. 2) to be described later. ).

  Furthermore, the vehicle 1 includes an automatic travel device 2 as a configuration of a control system that controls the automatic travel of the vehicle 1, for example. The automatic travel device 2 is a device that automatically controls the output of the engine 3, the connection / disconnection of the clutch 4, and the speed change of the transmission 5 to automatically travel the vehicle 1, and includes a plurality of control devices.

  Specifically, the automatic travel device 2 includes an engine ECU (engine control device) 10, a power transmission ECU (power transmission control device) 11, a target vehicle speed setting device 13, an increase / decrease value setting device 14, and road information acquisition. It has the apparatus 20, the vehicle information acquisition apparatus 30, and the traveling control apparatus 100. The engine ECU 10, the power transmission ECU 11, and the travel control device 100 are connected to each other via an in-vehicle network so that necessary data and control signals can be transmitted / received to / from each other. Further, the target vehicle speed setting device 13 and the increase / decrease value setting device 14 may not be included in the automatic travel device 2.

  The engine ECU 10 controls the output of the engine 3. The power transmission ECU 11 controls the connection and disconnection of the clutch 4 and the shift of the transmission 5.

  The target vehicle speed setting device 13 sets the target vehicle speed V ′ when the vehicle 1 automatically travels in the travel control device 100. The increase / decrease value setting device 14 sets the speed decrease value -va and the speed increase value + vb during automatic traveling of the vehicle 1 in the travel control device 100. These values V ′, −va, + vb are parameters used for the automatic traveling of the vehicle 1.

  The target vehicle speed setting device 13 and the increase / decrease value setting device 14 include, for example, an information input interface such as a display with a touch panel arranged on a dashboard (not shown) of the driver's seat, and accept the setting of the parameters from the driver. The target vehicle speed V ′, the speed decrease value −va, and the speed increase value + vb are appropriately referred to as “setting information”.

  The road information acquisition device 20 acquires road information indicating road conditions and the current position of the vehicle 1 and outputs the road information to the travel control device 100. For example, the road information acquisition device 20 detects a distance or a vehicle speed difference between a current position acquisition device 21 that is a receiver of a satellite positioning system (GPS) and a surrounding traveling vehicle such as a preceding vehicle or a parallel running vehicle. Sensor 23. This ambient sensor 23 corresponds to an example of a detection unit 210 (see FIG. 2) described later. The current position acquisition device 21 may not be included in the road information acquisition device 20.

  The vehicle information acquisition device 30 acquires vehicle information indicating the operation content of the driver and the state of the vehicle 1 and outputs the vehicle information to the travel control device 100. For example, the vehicle information acquisition device 30 includes an accelerator sensor 31 that detects the amount of depression of the accelerator pedal, a brake switch 32 that detects whether or not the brake pedal is depressed, a shift lever 33, a turn signal switch 34, and the vehicle speed V of the vehicle 1. A vehicle speed sensor 35 is detected.

  The travel control device 100 generates a travel schedule including, for example, drive travel and inertia travel based on the above-described setting information, road information, and vehicle information. Then, the travel control device 100 controls each part of the vehicle 1 so that the vehicle 1 travels according to the generated travel schedule.

  In addition, the traveling control device 100 performs an operation (hereinafter referred to as automatic braking) for applying a braking force to the vehicle based on the calculated target deceleration, regardless of the driver's braking operation. Moreover, the traveling control apparatus 100 performs the operation | movement which cancels | releases automatic braking. Details of these operations will be described later.

<Configuration of travel control device>
Next, a travel control device according to an embodiment of the present disclosure and the surrounding configuration will be described with reference to FIG.

  FIG. 2 is a block diagram showing an example of the configuration of travel control apparatus 100 according to the present embodiment and the surrounding configuration.

  The detection unit 210 outputs radar waves such as millimeter waves and infrared rays toward the front of the vehicle, and detects the relative distance and relative speed between the object (for example, the preceding vehicle) and the host vehicle based on the reflected waves. Radar device. The detection unit 210 outputs a signal indicating a relative distance and a relative speed (hereinafter referred to as a detection signal) to the travel control device 100.

  The detection unit 210 may be a camera device that captures an object in front of the vehicle, or may be a combination of a radar device and a camera device.

  The travel control device 100 includes an execution determination unit 201, a threshold determination unit 202, and a braking instruction unit 203.

  The execution determination unit 201 determines whether to execute automatic braking based on the detection signal input from the detection unit 210.

  For example, when at least one of the relative distance and the relative speed of the detection signal satisfies a predetermined automatic braking execution condition, the execution determination unit 201 determines to execute automatic braking. The execution determination unit 201 determines that automatic braking is to be started before automatic braking is performed, and determines that automatic braking is to be continued when automatic braking is being performed.

  On the other hand, when at least one of the relative distance and the relative speed of the detection signal does not satisfy the predetermined automatic braking execution condition, the execution determination unit 201 determines that the automatic braking is not executed. The execution determination unit 201 determines that automatic braking is not started before execution of automatic braking, and determines that automatic braking is released (terminated) when automatic braking is being executed.

  The threshold determination unit 202 determines whether or not the target deceleration used for automatic braking is less than a predetermined threshold. Details of the target deceleration and the threshold will be described later.

  The braking instruction unit 203 instructs the brake control unit 220 to instruct a target deceleration and to release automatic braking (also referred to as releasing braking force).

  For example, before execution of automatic braking, when it is determined by the execution determination unit 201 to start automatic braking, the braking instruction unit 203 calculates a target deceleration based on the relative distance and relative speed of the detection signal, and the target A signal indicating deceleration (hereinafter referred to as a target deceleration signal) is output to the brake control unit 220.

  Further, for example, when the threshold determination unit 202 determines that the target deceleration is not less than the threshold during execution of automatic braking, and the execution determination unit 201 determines to continue execution of automatic braking, the braking instruction unit 203 calculates a target deceleration based on the relative distance and relative speed of the detection signal, and outputs the target deceleration signal to the brake control unit 220.

  Further, for example, during execution of automatic braking, the threshold determination unit 202 determines that the target deceleration is not less than the threshold, and the execution determination unit 201 determines that automatic braking is not continued (releases automatic braking). In this case, the braking instruction unit 203 outputs a signal (hereinafter referred to as a first release instruction signal) instructing a sudden release of automatic braking to the brake control unit 220. Details of the sudden release of automatic braking will be described later.

  In addition, for example, when the threshold determination unit 202 determines that the target deceleration is less than the threshold during execution of automatic braking, the braking instruction unit 203 instructs a signal (hereinafter referred to as a first instruction) to gently release automatic braking. 2) (referred to as a release instruction signal 2) to the brake control unit 220. Details of the gradual release of automatic braking will be described later.

  The brake control unit 220 is, for example, a brake control device such as EBS (Electronic Braking System), etc. The brake control unit 220 receives the target deceleration signal input from the braking instruction unit 203 of the travel control device 100 and the first release. The brake unit 230 is controlled based on the instruction signal or the second release instruction signal.

  For example, when the target deceleration signal is input from the braking instruction unit 203, the brake control unit 220 controls the brake unit 230 so as to apply a braking force to the vehicle based on the target deceleration signal.

  Further, for example, when the first release instruction signal is input from the braking instruction unit 203, the brake control unit 220 suddenly releases the braking force applied to the vehicle based on the first release instruction signal. The brake unit 230 is controlled.

  In addition, for example, when the second release instruction signal is input from the braking instruction unit 203, the brake control unit 220 gently releases the braking force applied to the vehicle based on the second release instruction signal. The brake unit 230 is controlled.

  The brake unit 230 increases or decreases the braking force according to the control of the brake control unit 220, and applies the braking force or releases the braking force.

  2 illustrates a configuration in which the brake control unit 220 is provided separately from the travel control device 100, the brake control unit 220 may be included in the travel control device 100.

<Operation of the travel control device>
Next, the operation of the travel control apparatus 100 according to the present embodiment will be described with reference to FIGS.

  FIG. 3 is a flowchart showing an example of the operation of travel control apparatus 100 according to the present embodiment. FIG. 4 is a diagram illustrating an example of the target deceleration. In FIG. 4, the vertical axis represents the target deceleration value (unit: G), and the horizontal axis represents time. On the horizontal axis in FIG. 4, it is assumed that time elapses from left to right in the figure.

  Hereinafter, the operation after the execution determination unit 201 determines to start execution of automatic braking based on the detection signal will be described as an example. The processing operation shown in FIG. 3 is repeated until it is determined that the execution of the automatic braking is started and the release of the automatic braking is completed.

  First, the braking instruction unit 203 calculates a target deceleration based on the relative distance and relative speed of the detection signal input from the detection unit 210, and outputs a target deceleration signal indicating the calculated target deceleration to the brake control unit 220. (Step S1). The target deceleration is a change in speed per unit time (acceleration in the deceleration direction).

  Here, an example of the target deceleration calculated by the braking instruction unit 203 will be described with reference to FIG. In FIG. 4, for example, when the time t1 is the start time of automatic braking and the time t2 is the release time of automatic braking, the target deceleration is calculated so as to gradually increase between time t1 and time t2. Is done. Then, the braking instruction unit 203 outputs a target deceleration signal indicating the calculated target deceleration to the brake control unit 220 as time elapses. The brake control unit 220 controls the brake unit 230 so as to apply a braking force based on the target deceleration signal.

  Next, the threshold determination unit 202 determines whether or not the target deceleration of the target deceleration signal output from the braking instruction unit 203 is less than the threshold Th (Step S2).

  In FIG. 4, the threshold value Th is set to a value in the vicinity of −0.5 G which is the maximum target deceleration (for example, −0.4 G), but is not limited thereto. The threshold value Th may be set within a deceleration range that does not give a great discomfort (discomfort due to loss of inertial force) to the vehicle occupant even if the automatic braking is suddenly released.

  As a result of the determination in step S2, if the target deceleration is not less than the threshold (step S2: NO), the flow proceeds to step S5. The processing after step S5 will be described later.

  As a result of the determination in step S2, if the target deceleration is less than the threshold (step S2: YES), the execution determination unit 201 continues automatic braking during execution based on the relative distance and relative speed of the detection signal. It is determined whether or not (step S3).

  For example, when the relative distance between the preceding vehicle and the host vehicle is smaller than when automatic braking is started, the execution determination unit 201 determines to continue automatic braking. On the other hand, for example, when the relative distance between the preceding vehicle and the host vehicle is larger than when the automatic braking is started, or when the detected preceding vehicle no longer exists in front of the host vehicle The determination unit 201 determines that automatic braking is not continued.

  As a result of the determination in step S3, when the execution determination unit 201 determines that automatic braking is to be continued (step S3: YES), the flow returns to step S1. In this case, the braking instruction unit 203 continues to output the target deceleration signal.

  On the other hand, as a result of the determination in step S3, when the execution determination unit 201 determines that the automatic braking is not continued (step S3: NO), the braking instruction unit 203 instructs the second release instruction to instruct a gentle release of the automatic braking. A signal is output to the brake control unit 220.

  The second release instruction signal includes an instruction of timing for starting the gentle release of the automatic braking. This timing is, for example, the timing after a predetermined time has elapsed since reaching the maximum target deceleration (for example, time t2 in FIG. 4). Further, this timing is calculated by the braking instruction unit 203 at the start of automatic braking, for example.

  Based on the second release instruction signal, the brake control unit 220 controls the brake unit 230 so as to gently release the automatic braking (step S4).

  For example, when the deceleration of -0.5G is generated, the brake control unit 220 releases the deceleration in 0.5 seconds (for example, between time points t2 and t3 in FIG. 4). 230 is controlled. In addition, the numerical value of deceleration and time is not limited to this. In the gentle release of automatic braking, it is preferable that the ratio of the target deceleration with respect to the time required for the release is controlled to be 1 or less.

  According to this control, the inertial force is gradually released, so that even when the deceleration is large, the occupant hardly feels discomfort due to the loss of the inertial force. Further, it is possible to reduce cargo collapse due to loss of inertia force and damage to the vehicle.

  As a result of the determination in step S2, if the target deceleration is not less than the threshold value (step S2: NO), the execution determination unit 201 executes based on the relative distance and the relative speed of the detection signal as in step S3 described above. It is determined whether or not to continue the automatic braking (step S5).

  As a result of the determination in step S5, when the execution determination unit 201 determines to continue automatic braking (step S5: YES), the flow returns to step S1. In this case, the braking instruction unit 203 continues to output the target deceleration signal.

  On the other hand, as a result of the determination in step S5, when the execution determination unit 201 determines that automatic braking is not continued (step S5: NO), the braking instruction unit 203 instructs the first release instruction to instruct a sudden release of automatic braking. A signal is output to the brake control unit 220.

  The first release instruction signal includes an instruction of timing for starting a sudden release of automatic braking. This timing is, for example, a timing immediately after the brake control unit 220 inputs the first release instruction signal.

  Based on the first release instruction signal, the brake control unit 220 controls the brake unit 230 to release the automatic braking suddenly (step S6).

  For example, when a deceleration of −0.2 G is generated, the brake control unit 220 controls the brake unit 230 so as to release the deceleration in 0.1 seconds. In addition, the numerical value of deceleration and time is not limited to this. In the case of sudden release of automatic braking, it is preferable to control the ratio of the target deceleration with respect to the time required for release to be greater than 1.

  According to this control, the inertial force is quickly lost, but since the deceleration is small, the passenger hardly feels discomfort due to the loss of inertial force. In addition, since the brake is released in a short time, the speed before returning to the original speed (also referred to as the original vehicle speed) is quicker, and the return to the original speed is delayed, reducing the discomfort felt by the passengers. it can.

<Effects of the present embodiment>
As described above, the traveling control apparatus 100 according to the present embodiment, when it is determined that the target deceleration is less than the threshold value, performs automatic braking (control) compared to the case where it is determined that the target deceleration is not less than the threshold value. The automatic braking is released so that the ratio of the target deceleration to the time taken to release the (power) is reduced. For example, the traveling control device 100 releases the automatic braking gently when the target deceleration is less than the threshold, and suddenly releases the automatic braking when the target deceleration is not less than the threshold.

  As a result, the traveling control apparatus 100 according to the present embodiment can reduce the discomfort felt by the occupant due to a sudden loss of inertia force when a large deceleration occurs when the automatic braking is released, and the inertial force It is possible to reduce the collapse of the load and the damage to the vehicle. On the other hand, when a small deceleration occurs when the automatic braking is released, the traveling control device 100 can accelerate the return to the vehicle speed before the start of the automatic braking, and the occupant is delayed by the return to the original vehicle speed. Can reduce discomfort. Therefore, traveling control device 100 according to the present embodiment can improve comfort when automatic braking is released.

<Modification of the present embodiment>
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made.

  For example, in the above-described embodiment, the traveling control device 100 includes the execution determination unit 201, the threshold determination unit 202, and the braking instruction unit 203. However, the traveling control device 100 includes at least the threshold determination unit 202 and the braking instruction unit. 203 may be provided.

  Further, for example, each function of the travel control device 100 described in the above embodiment can be realized by a computer program. Specifically, a CPU (Central Processing Unit) included in a computer copies a program stored in a storage device to a RAM (Random Access Memory), and sequentially reads instructions from the RAM and executes them. Each function described above is realized.

<Summary of this disclosure>
The travel control device of the present disclosure is a travel control device that applies a braking force to a vehicle based on a target deceleration, the threshold determination unit that determines whether the target deceleration is less than a threshold, and the target When it is determined that the deceleration is less than the threshold, the ratio of the target deceleration to the time taken to release the braking force is smaller than when the target deceleration is determined not to be less than the threshold. A braking instruction unit for releasing the braking force.

  In the travel control device, when it is determined that the target deceleration is less than the threshold, the braking instruction unit releases the braking force so that the ratio becomes 1 or less, and the target deceleration If it is determined that is not less than the threshold, the braking force may be released so that the ratio is greater than 1.

  The travel control device may further include an execution determination unit that determines whether to apply the braking force or to release the braking force based on a detection result of an object in front of the vehicle. The braking instruction unit calculates the target deceleration based on the detection result when the execution determination unit determines to apply the braking force, and calculates the braking force based on the calculated target deceleration. You may make it provide.

  The travel control method of the present disclosure is a travel control method for applying a braking force to a vehicle based on a target deceleration, the step of determining whether or not the target deceleration is less than a threshold, and the target deceleration When it is determined that is less than the threshold, the braking force is released so that the ratio of the target deceleration to the time taken to release the braking force is smaller than when it is determined that it is not less than the threshold. Steps.

  The travel control program of the present disclosure is a travel control program that applies a braking force to a vehicle based on a target deceleration, the process for determining whether the target deceleration is less than a threshold, and the target deceleration When it is determined that is less than the threshold, the braking force is released so that the ratio of the target deceleration to the time taken to release the braking force is smaller than when it is determined that it is not less than the threshold. And causing the computer to execute the process.

  The travel control device, the travel control method, and the travel control program of the present disclosure are useful as a travel control device, a travel control method, and a travel control program that control the travel of the vehicle.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Automatic traveling device 3 Engine 4 Clutch 5 Transmission 6 Propulsion shaft 7 Differential device 8 Drive shaft 9 Wheel 10 ECU for engine
11 Power transmission ECU
DESCRIPTION OF SYMBOLS 13 Target vehicle speed setting apparatus 14 Increase / decrease value setting apparatus 20 Road information acquisition apparatus 21 Current position acquisition apparatus 23 Ambient sensor 30 Vehicle information acquisition apparatus 31 Acceleration sensor 32 Brake switch 33 Shift lever 34 Turn signal switch 35 Vehicle speed sensor 40 Braking apparatus 41 Foot brake 42 Retarder 43 Auxiliary brake 100 Travel control device 210 Detection unit 201 Execution determination unit 202 Threshold determination unit 203 Braking instruction unit 220 Brake control unit 230 Brake unit

Claims (5)

A travel control device that applies braking force to a vehicle based on a target deceleration,
A threshold determination unit that determines whether or not the target deceleration is less than a threshold;
When it is determined that the target deceleration is less than the threshold, the ratio of the target deceleration with respect to the time taken to release the braking force, compared to when it is determined that the target deceleration is not less than the threshold A braking instruction section for releasing the braking force so that the
Travel control device. The braking instruction section
When it is determined that the target deceleration is less than the threshold, the braking force is released so that the ratio is 1 or less,
If it is determined that the target deceleration is not less than the threshold, the braking force is released so that the ratio is greater than 1.
The travel control device according to claim 1. An execution determination unit that determines whether to apply the braking force or to release the braking force based on a detection result of an object in front of the vehicle;
The braking instruction section
When the execution determination unit determines to apply the braking force, the target deceleration is calculated based on the detection result, and the braking force is applied based on the calculated target deceleration.
The travel control apparatus according to claim 1 or 2. A travel control method for applying braking force to a vehicle based on a target deceleration,
Determining whether the target deceleration is less than a threshold;
When it is determined that the target deceleration is less than the threshold, the control is performed so that the ratio of the target deceleration to the time taken to release the braking force is smaller than when it is determined that the target deceleration is not less than the threshold. Releasing the power, and
Travel control method. A travel control program for applying braking force to a vehicle based on a target deceleration,
A process for determining whether the target deceleration is less than a threshold;
When it is determined that the target deceleration is less than the threshold, the control is performed so that the ratio of the target deceleration to the time taken to release the braking force is smaller than when it is determined that the target deceleration is not less than the threshold. Causing the computer to execute the process of releasing the power,
Travel control program.

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