Parking brake control device of full-drive-by-wire unmanned vehicle

Abstract

The invention relates to a parking brake control device of a full-drive-by-wire unmanned vehicle, which is used for carrying out safe and stable switching decision on control instructions from two sources, namely, 'parking brake entering through human intervention and manual control 'and'zero target vehicle speed in an unmanned autonomous maneuvering state'. The system comprises an instruction fusion module, a comprehensive braking adjustment module and a parking behavior decision module. By judging and processing a personnel remote control instruction, an autonomous maneuvering system instruction and the state of the vehicle, the braking strength and the parking instruction decision are adjusted in real time, and the safe, stable and smooth parking function of the vehicle can be achieved. It is guaranteed that the vehicle can be stopped at any time according to the will of remote control personnel and can also be automatically stopped at the target position according to the track planned by the autonomous system.

Description

Technical Field

[0001] The present invention relates to a control method, and in particular to an automatic parking brake control device for a fully-wire-controlled unmanned vehicle that is switchable between a "remote control driving mode" and an "autonomous maneuvering driving mode", belonging to the technical field of motion control for fully-wire-controlled unmanned vehicles. Background Art

[0002] The fully controlled-by-wire vehicle is equipped with a service brake mechanism and a parking brake mechanism. The service brake mechanism can achieve infinitely continuous adjustment of the service brake strength within the range of 0 to 100%, while the parking brake system only has "release parking" (at this time the parking brake strength is 0, i.e. P fnl = 0) and "apply parking" (parking brake strength reaches the maximum, that is, P fnl =1) These two states.

[0003] For a fully wire-controlled unmanned vehicle with the function of "remote control driving and unmanned driving mode switchable", during autonomous maneuvering, the autonomous maneuvering system will send the desired vehicle speed V to the motion control system. tar The vehicle's motion control system can automatically adjust the driving and braking intensity to make the actual vehicle speed V act Close to V tar When the desired vehicle speed command V tar = 0, indicating that the autonomous mobility system expects the vehicle to stop. However, the autonomous mobility system will not issue a "parking brake" command to avoid conflict with the parking command in the remote control command. The architecture of the existing control method can be referred to in the attached Figure 1 .

[0004] When the vehicle reaches a certain target point, even if the autonomous mobility system sends a V tar = 0, if the ground has a certain slope, the vehicle may still slide down the slope at a low speed and cannot stay at the target position accurately. In this case, it is necessary to manually use remote control to put the vehicle into the parking state. Alternatively, the motion control system can be controlled according to V tar = 0 command information automatically enters the applied parking state. However, after actual vehicle testing, it was found that due to the disturbances that may exist in the calculation results of the autonomous maneuvering system and the information transmission process, V may also occur when the vehicle is not in a low-speed state. tar =0 instruction information. If only based on V tar =0, the vehicle will enter the parking state directly. The parking brake may be suddenly applied during driving, resulting in unstable driving. Summary of the Invention

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

[0006] A parking brake control device for a fully wire-controlled unmanned vehicle includes a command fusion module, an integrated brake adjustment module, and a parking behavior decision module; the command fusion module receives information from a remote control terminal and an autonomous maneuvering driving system, determines whether the autonomous maneuvering mode is activated, and determines whether the remote control terminal issues a parking or release command; if the remote control terminal 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 maneuvering mode is activated, the command fusion module sends an autonomous maneuvering mode activation signal to the integrated brake adjustment module; when the integrated brake adjustment module receives the autonomous maneuvering mode activation signal, it determines whether it is a service brake or a parking brake, and if it is a service brake, sends a command to the service brake actuator; if it is a parking brake, sends a command to the parking behavior decision module in the form of P2; the parking behavior decision module makes a judgment based on the currently received P1 and P2 commands, and sends a final parking brake control command to the parking brake actuator.

[0007] Furthermore, the integrated brake adjustment module determines that the service brake is applied under the condition that the actual vehicle speed in the autonomous maneuvering mode is greater than the sum of the target vehicle speed and the deceleration speed threshold.

[0008] Furthermore, the integrated brake adjustment module determines that the parking brake is applied when the target vehicle speed in the autonomous maneuvering mode 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 a parking speed threshold.

[0009] Furthermore, if the parking button on the remote control is pressed, P1 = 1, ie, the parking is applied by the remote control; if the parking button on the remote control is lifted, P1 = 0, ie, the parking is released by the remote control.

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

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

[0012] If P1=1, the parking brake command is issued to the parking brake system regardless of whether the autonomous maneuvering driving mode is activated;

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

[0014] Otherwise, in any other case, the parking brake system is issued to release the parking brake.

[0015] Beneficial effects

[0016] (1) The present invention automatically applies the parking brake at the appropriate time by identifying and fusing remote control commands and autonomous driving system commands, thereby reducing the frequency of human remote control intervention and improving the vehicle's intelligence level;

[0017] (2) The present invention ensures that the parking brake is applied after the vehicle speed is reduced to a lower range by comprehensively considering the actual vehicle speed and the effectiveness of the autonomous driving system command (the duration must reach a threshold to be considered effective), thereby improving the stability of the vehicle during driving and parking.

[0018] (3) The application of the present invention can ensure that the unmanned vehicle stops correctly at the target point, while preventing the vehicle from slipping, improving the tracking accuracy of the autonomous maneuvering trajectory of the unmanned vehicle, and optimizing the parking control process and safety of the unmanned vehicle;

[0019] (4) The present invention is not limited to the type of vehicle. As long as the vehicle has the ability of wire control braking, the present invention can be applied, and has good versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[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 of the present invention;

[0022] Figure 3 Schematic diagram of the P2 switching strategy. DETAILED DESCRIPTION

[0023] The architecture of the control device of the present invention is as follows Figure 2 As shown, the control principle is as follows:

[0024] A. The command fusion module collects remote control command information and determines whether to activate the autonomous driving mode. It also determines and defines the "remote control parking command P1": if the remote control parking button is pressed, P1 = 1, indicating that the remote control has applied parking; if the remote control parking button is released, P1 = 0, indicating that the remote control has released parking.

[0025] B. If the autonomous maneuvering mode is not activated, the system is controlled only according to the remote parking command P1; if the autonomous maneuvering mode is activated, the integrated brake adjustment module is entered. When the actual vehicle speed V act ≥(expected vehicle speed V tar+1km / h), according to the difference e of the actual vehicle speed relative to the expected vehicle speed, the driving brake is gradually applied at a certain control rate, and the actual vehicle speed is adjusted;

[0026] C, in the autonomous driving mode activation state, if V tar = 0, according to the duration T tar = 0, it is judged whether the duration T s is greater than or equal to 1 second and V act is less than 1km / h, and the "autonomous driving system expected parking instruction P2" is determined and defined, specifically, if T s ≥ 1s and V act < 1km / h, P2 = 1, that is, the autonomous driving system is expected to apply parking; otherwise, P2 = 0, that is, the parking is expected to be released;

[0027] D, finally, the parking behavior decision module is entered, if P1 = 1, that is, the remote control applies parking, no matter whether the autonomous driving mode is activated or not, the final control instruction P fnl = 1 (that is, the parking brake is applied) is issued to the parking brake system; if P1 = 0, and the autonomous driving mode is activated, and P2 = 1, the final parking brake control instruction P fnl = 1; in any other case, P fnl = 0 (that is, the parking brake is released). The strategy principle of the parking behavior decision module is shown in the attached Figure 3 .

[0028] The present application makes safe and stable switching decisions for control instructions from two sources, "human intervention, manual control into parking brake" and "target vehicle speed of zero in autonomous driving state", through the judgment and processing of personnel remote control instructions (parking), autonomous driving system instructions (expected speed), and vehicle state (current speed), real-time adjustment of brake intensity and parking instruction decision, which can realize the above-mentioned safe, stable and smooth parking function of the vehicle, and ensure that the vehicle can be stopped at any time according to the wishes of the remote control personnel, and can be automatically stopped at the target position according to the trajectory planned by the autonomous system. Compared with the existing control strategy of relying solely on remote control personnel to manually control the parking brake, the number of personnel interventions and the control process during autonomous driving of unmanned vehicles are reduced, the trajectory tracking control accuracy of unmanned vehicles is improved, the unmanned vehicle parking control process is optimized, and the safety of unmanned vehicle maneuvering control is improved.

Claims

1. A parking brake control device for a fully controlled-by-wire unmanned vehicle, characterized by: The system includes a command fusion module, an integrated brake adjustment module, and a parking behavior decision module. The command fusion module receives information from the remote control terminal and the autonomous maneuvering system, determines whether the autonomous maneuvering mode is activated, and determines whether the remote control terminal has issued a parking or release command. If the remote control terminal issues a parking or release command, the command fusion module sends the information to the parking behavior decision module in the form of a P1 command. If the autonomous maneuvering mode is activated, the command fusion module sends an autonomous maneuvering mode activation signal to the integrated brake regulation module; When the integrated brake adjustment module receives the autonomous maneuvering mode activation signal, it determines whether it is service braking or parking braking. If it is service braking, it sends an instruction to the service brake actuator. If it is parking braking, it sends an instruction in the form of P2 to the parking behavior decision module; the parking behavior decision module makes a judgment based on the currently received P1 and P2 instructions, and sends a final parking brake control instruction to the parking brake actuator.

2. The parking brake control device for a fully controlled-by-wire unmanned vehicle according to claim 1, characterized in that: The determination condition for the integrated brake adjustment module to determine the service brake is that the actual vehicle speed in the autonomous maneuvering mode is greater than the sum of the target vehicle speed and the deceleration speed threshold.

3. The parking brake control device for a fully controlled-by-wire unmanned vehicle according to claim 1, characterized in that: The integrated brake adjustment module determines whether parking brake is applied based on the following conditions: the target vehicle speed is 0 in the autonomous maneuvering mode, the duration of the target vehicle speed being 0 is greater than a time threshold, and the actual vehicle speed is less than a parking speed threshold.

4. A parking brake control device for a fully controlled-by-wire unmanned vehicle according to any one of claims 1 to 3, characterized in that: If the parking button on the remote control is pressed, P1 = 1, that is, the remote control applies parking; if the parking button on the remote control is lifted, P1 = 0, that is, the remote control releases parking.

5. The parking brake control device for a fully controlled-by-wire unmanned vehicle according to claim 4, characterized in that: When P2=1, it indicates that the parking brake is expected to be applied when the autonomous maneuvering driving mode is activated. When P2=0, it indicates that the parking brake is expected to be released when the autonomous maneuvering driving mode is activated.

6. The parking brake control device for a fully controlled-by-wire unmanned vehicle according to claim 5, characterized in that: The working process of the parking behavior decision module is as follows: If P1=1, the parking brake command is issued to the parking brake system regardless of whether the autonomous maneuvering driving mode is activated; If P1 = 0, and the autonomous maneuvering mode is activated, and P2 = 1, a parking brake command is issued to the parking brake system; Otherwise, in any other case, the parking brake system is issued to release the parking brake.

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