A parking brake control device for a fully automated unmanned vehicle

Abstract

The application relates to a parking brake control device of a full-line controlled unmanned vehicle, which carries out safe and stable switching decisions on control instructions from two sources, i.e. "artificial intervention and manual control into parking brake" and "target vehicle speed of zero in an unmanned autonomous mobile state", and comprises an instruction fusion module, a comprehensive brake adjustment module and a parking behavior decision module. Through judgment and processing of personnel remote control instructions, autonomous mobile system instructions and the vehicle's own state, the brake intensity and parking instruction decisions are adjusted in real time, so that the vehicle can realize safe, stable and smooth parking functions, and the vehicle can be stopped at any time according to the will of the remote control personnel and automatically stopped at a target position according to the track planned by the autonomous system.

Description

Technical Field

[0001] This invention relates to a control method, specifically to an automatic parking brake control device for a fully drive-by-wire unmanned vehicle that can switch between "remote driving mode" and "autonomous driving mode", belonging to the field of motion control technology for fully drive-by-wire unmanned vehicles. Background Technology

[0002] The fully drive-by-wire vehicle is equipped with both a service brake mechanism and a parking brake mechanism. The service brake mechanism allows for stepless continuous adjustment of the braking intensity within a range of 0% to 100%; while the parking brake system only operates when the parking brake is released (at which point the parking brake intensity is 0, i.e., P). fnl =0) and "Apply parking brake" (the parking brake intensity reaches its maximum, i.e., P fnl =1) These two states.

[0003] For fully drive-by-wire unmanned vehicles with the ability to switch between remote control and driverless modes, during autonomous maneuvering, the autonomous maneuvering system sends the desired vehicle speed V to the motion control system. tar Command. The vehicle's motion control system can automatically adjust the driving and braking intensity to maintain the vehicle's actual speed V. act Approaching V tar When the desired vehicle speed command V tar When the value is 0, it indicates that the autonomous driving system expects the vehicle to stop. However, the autonomous driving system will not issue a "parking brake" command to avoid conflict with the parking command in the remote control. The architecture of existing control methods can be found in the appendix. Figure 1 .

[0004] When the vehicle reaches a certain target location, even if the autonomous driving system issues a V... tar Even with a desired speed command of 0, if the ground has a certain slope, the vehicle may still roll downhill at a low speed and fail to stop accurately at the target position. In this case, manual remote control is required to put the vehicle into parking mode. Alternatively, the motion control system can adjust the speed based on V... tar The command message = 0 automatically initiates the parking state. However, actual vehicle testing revealed that due to potential disturbances in the autonomous driving system's calculations and information transmission, V may occur even when the vehicle is not at a low speed. tar =0 instruction information. If only based on V tar When the value is 0, the vehicle directly enters the parking state. During driving, the parking brake may be applied suddenly, which may lead to driving instability. Summary of the Invention

[0005] In view of this, the present invention proposes a parking brake control device for a fully drive-by-wire unmanned vehicle. The present invention is an automatic parking brake control device for a fully drive-by-wire unmanned vehicle that can switch between "remote driving mode" and "autonomous maneuvering driving mode," and the specific technical solution is as follows:

[0006] A parking brake control device for a fully automated guided vehicle (AGV) includes a command fusion module, a comprehensive braking adjustment module, and a parking behavior decision module. The command fusion module receives information from a remote control and an autonomous driving system, determines whether the autonomous driving mode is activated, and determines whether the remote control has issued a parking or release command. If the remote control issues a parking or release command, the command fusion module sends information to the parking behavior decision module in the form of a P1 command. If the autonomous driving mode is activated, the command fusion module sends an autonomous driving mode activation signal to the comprehensive braking adjustment module. When the comprehensive braking adjustment module receives the autonomous driving mode activation signal, it determines whether it is a service brake or a parking brake. If it is a service brake, it sends a command to the service brake actuator; if it is a parking brake, it sends a command to the parking behavior decision module in the form of a P2 command. The parking behavior decision module makes a judgment based on the currently received P1 and P2 commands and issues a final parking brake control command to the parking brake actuator.

[0007] Furthermore, the integrated braking adjustment module determines the driving braking condition by stating that the actual vehicle speed in autonomous maneuvering mode is greater than the sum of the target vehicle speed and the deceleration speed threshold.

[0008] Furthermore, the integrated braking adjustment module determines the parking brake condition as follows: in autonomous maneuvering mode, the target vehicle speed is 0, the duration of the target vehicle speed being 0 is greater than a time threshold, and the actual vehicle speed is less than the parking speed threshold.

[0009] Furthermore, if the parking button on the remote control is pressed, then P1 = 1, meaning the parking is applied remotely; if the parking button on the remote control is released, then P1 = 0, meaning the parking is released remotely.

[0010] Furthermore, when P2=1, it indicates that the parking brake is expected to be applied when the autonomous driving mode is activated, and when P2=0, it indicates that the parking brake is expected to be released when the autonomous driving mode is activated.

[0011] Furthermore, the working process of the parking behavior decision module is as follows:

[0012] If P1 = 1, then regardless of whether the autonomous driving mode is activated, a parking brake command will be issued to the parking brake system.

[0013] If P1 = 0, and the autonomous driving mode is activated, and P2 = 1, a parking brake command is issued to the parking brake system.

[0014] Otherwise, in any other situation, a release of the parking brake will be issued to the parking brake system.

[0015] Beneficial effects

[0016] (1) This invention identifies and fuses remote control commands and autonomous driving system commands, and automatically applies parking brakes at appropriate times, thereby reducing the frequency of remote control intervention by personnel and improving the intelligence level of the vehicle.

[0017] (2) By comprehensively considering the actual vehicle speed and the effectiveness of the autonomous driving system commands (the system is only considered effective when the duration reaches a threshold), this invention ensures that the vehicle speed is reduced to a lower range before the parking brake is applied, thereby improving the stability of the vehicle's driving and parking processes.

[0018] (3) By applying this invention, it can be ensured that the above-mentioned unmanned vehicles stop correctly at the target location, while avoiding vehicle slippage and damage, improving the accuracy of autonomous driving trajectory tracking of unmanned vehicles, and optimizing the parking control process and safety of unmanned vehicles.

[0019] (4) This invention is not limited to vehicle type. As long as the vehicle has brake-by-wire capability, this invention can be applied, and it has good versatility. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the existing parking brake control architecture;

[0021] Figure 2 This is a schematic diagram of the architecture of the control device described in this invention;

[0022] Figure 3 This is a schematic diagram illustrating the principle of the P2 switching strategy. Detailed Implementation

[0023] The architecture of the control device described in this invention is as follows: Figure 2 As shown, the control principle follows these steps:

[0024] A. The command fusion module collects remote control command information and determines whether the autonomous driving mode is activated. At the same time, it judges and defines "remote terminal parking command P1": if the remote terminal parking button is pressed, then P1=1, that is, the remote terminal applies parking; if the remote terminal parking button is released, then P1=0, that is, the remote terminal releases parking.

[0025] B. If the autonomous maneuvering mode is not activated, the system will only be controlled according to the remote parking command P1; if the autonomous maneuvering mode is activated, the system will enter the integrated braking adjustment module, and when the actual vehicle speed V... act ≥(desired vehicle speed V) tar+1km / h), based on the difference e between the actual vehicle speed and the desired vehicle speed, the driving brake is gradually applied with a certain control rate to adjust the actual vehicle speed.

[0026] C. In the autonomous maneuver mode, if V tar =0, then according to V tar =0 duration T s Is it greater than or equal to 1 second and V act Determine whether the speed is less than 1 km / h and define "Autonomous Mobility System Expected Parking Command P2". Specifically, if T s ≥1s and V act If the speed is less than 1 km / h, then P2 = 1, meaning the autonomous driving system expects to apply parking; otherwise, P2 = 0, meaning it expects to release parking.

[0027] D. Finally, the parking behavior decision module is entered. If P1 = 1, that is, parking is applied remotely, then the final control command P is issued to the parking brake system regardless of whether the autonomous driving mode is activated. fnl =1 (i.e., applying the parking brake); if P1=0, and the autonomous driving mode is activated, and P2=1, then the final parking brake control command P fnl =1; in any other case, P fnl =0 (i.e., the parking brake is released). See the appendix for the strategy principle of the parking behavior decision module. Figure 3 .

[0028] This invention addresses the safe and stable switching decisions for control commands originating from two sources: "human intervention / manual control to engage the parking brake" and "target vehicle speed at zero in autonomous driving mode." By processing and judging the remote control commands (park / ), autonomous driving system commands (desired speed), and the vehicle's own state (current speed), it adjusts braking intensity and parking command decisions in real time. This enables safe, stable, and smooth parking of the vehicle, ensuring it can stop at any time according to the remote operator's wishes and automatically stop at the target location according to the trajectory planned by the autonomous system. Compared to existing control strategies that rely solely on manual control of the parking brake, this invention reduces the number of human interventions and the complexity of the control process during autonomous driving, improves the accuracy of trajectory tracking control, optimizes the parking control process, and ultimately enhances the safety of autonomous vehicle maneuver control.

Claims

1. A parking brake control device for a fully drive-by-wire unmanned vehicle, characterized in that: It includes a command fusion module, a comprehensive braking adjustment module, and a parking behavior decision module. The command fusion module receives information from the remote control and the autonomous driving system, determines whether the autonomous driving mode is activated, and determines whether the remote control has issued a parking or release command. If the remote control issues a parking or release command, the command fusion module will... The P1 command is used to send information to the parking behavior decision module; If the autonomous maneuvering mode is activated, the command fusion module will send an autonomous maneuvering mode activation signal to the integrated braking adjustment module; When the integrated braking adjustment module receives the autonomous maneuvering mode activation signal, it determines whether it is driving brake or parking brake. If it is driving brake, it sends a command to the driving brake actuator. If it is parking brake, it sends a command to the parking behavior decision module in P2 form. The parking behavior decision module makes a judgment based on the currently received P1 and P2 commands and issues the final parking brake control command to the parking brake actuator. The integrated braking adjustment module determines the driving braking condition when the actual vehicle speed in autonomous maneuver mode is greater than the sum of the target vehicle speed and the deceleration speed threshold. The integrated braking adjustment module determines the parking brake condition as follows: the target vehicle speed is 0 in autonomous maneuver mode, the duration of the target vehicle speed being 0 is greater than a time threshold, and the actual vehicle speed is less than the parking speed threshold. The working process of the parking behavior decision module is as follows: like Then, regardless of whether the autonomous driving mode is activated, a parking brake command will be issued to the parking brake system. like And activate autonomous driving mode, and The system issues a command to apply the parking brake to the parking brake system. Otherwise, in any other situation, a release of the parking brake will be issued to the parking brake system.

2. The parking brake control device for a fully drive-by-wire unmanned vehicle according to claim 1, characterized in that: If the parking button on the remote is pressed, then That is, the parking brake is applied remotely; if the parking brake button on the remote is released, then This means remotely releasing the parking brake.

3. The parking brake control device for a fully drive-by-wire unmanned vehicle as described in claim 2, characterized in that: When the autonomous driving mode is activated, it indicates that the parking brake is expected to be applied. When the autonomous driving mode is activated, it indicates that the parking brake is expected to be released.

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