Autonomous ditch crossing control system and method for six-wheel independent drive unmanned vehicle

Abstract

The invention relates to the field of unmanned combat vehicle motion control, in particular to an autonomous ditch crossing control system and method for a six-wheel independent drive unmanned vehicle, and a ditch crossing mode is added in autonomous driving modes of the unmanned vehicle (namely, the autonomous driving modes comprise a common maneuvering mode and a ditch crossing mode). According to the method, the unmanned vehicle can smoothly cross the ditch in an autonomous driving mode, the unmanned vehicle can smoothly pass through the ditch terrain without manual intervention, and auxiliary climbing equipment such as a telescopic bridge / folding bridge system does not need to be adopted to assist the unmanned vehicle to cross the ditch at all.

Description

Technical Field

[0001] The present invention relates to the field of unmanned combat vehicle motion control, and in particular to an autonomous trench crossing control system and method for a six-wheel independently driven unmanned combat vehicle. Background Art

[0002] like Figure 1 As shown in the figure, a certain unmanned combat vehicle with a variable wheelbase mainly uses manual control of a remote control terminal for maneuvering. The combat vehicle is a six-wheeled independent drive unmanned vehicle with a variable wheelbase, including a perception sensor, a posture sensor, an autonomous driving controller, a suspension controller, a vehicle controller, a motor controller, and a steering controller. The autonomous driving controller is mainly responsible for receiving and processing the data of the perception sensor and the posture sensor, planning the autonomous maneuvering behavior of the unmanned vehicle, generating speed and steering related control instructions to send to the vehicle controller, and suspension height and wheelbase change instructions to the suspension controller; the suspension controller controls the relevant actuators to adjust the wheelbase and suspension height; the vehicle controller parses the lateral and longitudinal motion control instructions input by the autonomous driving controller, generates torque instructions to send to the motor controller to realize the longitudinal control of the vehicle, and generates steering instructions to the steering controller to realize the lateral motion control of the vehicle.

[0003] At present, unmanned vehicles using this control mode can only drive autonomously on conventional simple terrain (such as cement roads, etc.), and cannot successfully cross trenches in autonomous driving mode. Human intervention is required to enable the unmanned vehicle to successfully pass through trench terrain. For example, auxiliary climbing equipment such as retractable bridge / folding bridge system is used to assist the unmanned vehicle to cross the trench.

[0004] How to enable unmanned vehicles to not only drive autonomously in conventional simple terrain but also pass through complex trench terrain without human intervention has always been a problem that technical personnel in this field need to solve urgently. Summary of the invention

[0005] The purpose of the present invention is to address the corresponding deficiencies in the prior art and to provide a control system and method for an autonomous trench crossing control system for a six-wheel independently driven unmanned vehicle. A trench crossing mode is added to the autonomous driving mode of the unmanned vehicle (that is, the autonomous driving mode includes a normal maneuvering mode and a trench crossing mode). Combined with the perception capabilities of traditional autonomous driving sensors, the unmanned vehicle can smoothly cross the trench in the autonomous driving mode without the need for human intervention, and the unmanned vehicle can smoothly pass through the trench terrain. There is no need to use auxiliary climbing equipment such as a retractable bridge / folding bridge system to assist the unmanned vehicle in crossing the trench.

[0006] The object of the present invention is achieved by adopting the following scheme: a method for controlling a six-wheel independently driven unmanned vehicle using an autonomous trench crossing control system, comprising the following steps: 1) Keep the control mode of the unmanned vehicle in the normal maneuvering mode, and use the positioning module to collect the output data of the on-board sensor to obtain the position and posture data of the unmanned vehicle; 2) Use the perception module to receive and analyze the point cloud data of the lidar to determine in real time whether there is a trench in front of the unmanned vehicle: 2-1) If there is no trench in front of the unmanned vehicle, the unmanned vehicle continues to maintain the normal maneuvering mode; 2-2) If there is a trench in front of the unmanned vehicle, the timing of entering the trench crossing mode is determined based on the point cloud data of the LiDAR and the position data of the unmanned vehicle; 3) When the unmanned vehicle enters the trench crossing mode, the path planning module issues a control command to slow down the unmanned vehicle, while the suspension control module controls the middle wheel of the unmanned vehicle to move toward the rear axle, so that the center of gravity of the unmanned vehicle moves backward until the middle wheel moves into place; 4) The trench-crossing planning module is used to calculate the first moving distance of the unmanned vehicle forward, so that the motion control module controls the unmanned vehicle to move forward according to the first moving distance until the state management module determines that the middle wheel of the unmanned vehicle crosses the trench according to the data of the perception module and the positioning module; 5) The trench crossing planning module is used to plan the action sequence for the middle wheel to move toward the rear axle. The motion control module controls the unmanned vehicle to perform rotational braking on the middle wheel according to the planned action sequence. At the same time, the suspension control module controls the middle wheel of the unmanned vehicle to move toward the front axle according to the planned action sequence, so that the center of gravity of the unmanned vehicle moves forward until the middle wheel moves into place. 6) The trench-crossing planning module calculates the second moving distance of the unmanned vehicle forward, and enables the motion control module to control the unmanned vehicle to move forward according to the second moving distance, until the state management module determines that the rear wheels of the unmanned vehicle cross the trench based on the data of the perception module and the positioning module; 7) The trench crossing planning module controls the middle wheel to move to the middle axis position, allowing the unmanned vehicle to re-enter the normal maneuvering mode.

[0007] Preferably, the posture data includes the pitch angle, yaw angle, pitch angle, and three-axis acceleration of the unmanned vehicle.

[0008] Preferably, a distance threshold is set so that the unmanned vehicle can determine in real time whether there is a trench ahead.

[0009] Preferably, the unmanned vehicle performs path planning by a path planning module in the normal maneuvering mode to determine the driving speed and driving route of the unmanned vehicle at each stage.

[0010] Preferably, in step 2-2), the timing of entering the trench crossing mode is determined as follows: Based on the point cloud data of the laser radar and the position data of the unmanned vehicle, the trench width and the relative position relationship between the trench and the unmanned vehicle are calculated. Then, the state management module determines whether to enter the trench crossing mode based on the position data of the unmanned vehicle and the relative position relationship between the trench and the unmanned vehicle: ① If the relative position relationship between the trench and the unmanned vehicle is not vertical, the unmanned vehicle continues to maintain the normal maneuvering mode; ② If the relative position relationship between the trench and the unmanned vehicle is vertical, the unmanned vehicle enters the trench crossing mode.

[0011] The autonomous trench crossing control system described in the above method is applicable to a six-wheel independently driven unmanned vehicle. The autonomous trench crossing control system includes a positioning module, a perception module, a state management module, a path planning module, a trench crossing planning module, a motion control interface, and a suspension control interface, wherein: The positioning module is used to analyze the data of vehicle-mounted sensors such as GPS and IMU to obtain the posture data and GPS position data of the unmanned combat vehicle; The perception module is used to receive and analyze the point cloud data of the laser radar, determine in real time whether there is a trench in front of the unmanned vehicle, and calculate the width of the trench and the relative position relationship between the trench and the unmanned vehicle in combination with the posture data of the unmanned vehicle; The state management module is used to determine whether the unmanned vehicle adopts the normal maneuvering mode or the trench crossing mode as the current control mode according to the relative position relationship between the trench and the unmanned vehicle and the posture data of the unmanned vehicle; The path planning module is used for planning the driving path of the unmanned vehicle and determining the driving path and driving speed of the unmanned vehicle at each stage; The trench crossing planning module is used to determine the trench crossing action plan of the unmanned vehicle in the trench crossing mode, and calculate the suspension target state corresponding to each stage in the trench crossing action plan; The motion control module is used to calculate the control instructions of the unmanned vehicle according to the driving path planning or the trench crossing action planning, and send the control instructions to the vehicle controller; The suspension control module is used to calculate the suspension control instructions according to the suspension target states corresponding to each stage in the trench crossing action planning, and send the suspension control instructions to the suspension controller.

[0012] The beneficial effects of the present invention are as follows: Preferably, the posture data includes the pitch angle, yaw angle, pitch angle, and three-axis acceleration of the unmanned vehicle, so that the calculation result is more accurate.

[0013] Preferably, a distance threshold is set for the unmanned vehicle to determine in real time whether there is a trench ahead. The distance threshold is determined through a calibration test to ensure that the unmanned vehicle can cross the trench in the best condition.

[0014] The advantage of the present invention is that a trench crossing mode is added to the autonomous driving mode of the unmanned vehicle (i.e., the autonomous driving mode includes a normal maneuvering mode and a trench crossing mode), and combined with the sensing capabilities of traditional autonomous driving sensors, no additional hardware facilities need to be added, and the unmanned vehicle can smoothly cross the trench in the autonomous driving mode by relying solely on the original on-board sensors. This method of the present invention no longer requires manual intervention, and can enable the unmanned vehicle to smoothly pass through the trench terrain, and there is no need to use auxiliary climbing equipment such as a retractable bridge / folding bridge system to assist the unmanned vehicle in crossing the trench.

[0015] Glossary Wheelbase: The English name is Wheelbase, which generally refers to the distance from the center of the front axle to the center of the rear axle of the car. The variable wheelbase of the present invention means that the unmanned vehicle can move the middle wheel back and forth between the front and rear wheels by changing the distance between the middle axle and other axles. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the hardware system of the present invention; Figure 2 It is a schematic diagram of the architecture of the software system of the present invention; Figure 3 This is a flow chart of a method for controlling a six-wheel independently driven unmanned vehicle by the autonomous trench crossing control system of the present invention; Figure 4 A schematic diagram of the position of an unmanned vehicle before crossing a linear trench in an embodiment of the present invention; Figure 5 Schematic diagram of the position of the unmanned vehicle before crossing a non-linear trench in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] like Figure 2 As shown, an autonomous trench crossing control system for a six-wheel independently driven unmanned vehicle includes a positioning module, a perception module, a state management module, a path planning module, a trench crossing planning module, a motion control interface, and a suspension control interface, wherein: The positioning module is used to analyze the data of vehicle-mounted sensors such as GPS and IMU to obtain the posture data and GPS position data of the unmanned combat vehicle; The perception module is used to receive and analyze the point cloud data of the laser radar, determine in real time whether there is a trench in front of the unmanned vehicle, and calculate the width of the trench and the relative position relationship between the trench and the unmanned vehicle in combination with the posture data of the unmanned vehicle; The state management module is used to determine whether the unmanned vehicle adopts the normal maneuvering mode or the trench crossing mode as the current control mode according to the relative position relationship between the trench and the unmanned vehicle and the posture data of the unmanned vehicle; The path planning module is used for planning the driving path of the unmanned vehicle and determining the driving path and driving speed of the unmanned vehicle at each stage; The trench crossing planning module is used to determine the trench crossing action plan of the unmanned vehicle in the trench crossing mode, and calculate the suspension target state corresponding to each stage in the trench crossing action plan; The motion control module is used to calculate the control instructions of the unmanned vehicle according to the driving path planning or the trench crossing action planning, and send the control instructions to the vehicle controller; The suspension control module is used to calculate the suspension control instructions according to the suspension target states corresponding to each stage in the trench crossing action planning, and send the suspension control instructions to the suspension controller.

[0018] The method for controlling a six-wheel independently driven unmanned vehicle using the autonomous trench crossing control system comprises the following steps: 1) Keep the control mode of the unmanned vehicle in the normal maneuvering mode, and use the positioning module to collect the output data of the vehicle-mounted sensor to obtain the posture data of the unmanned vehicle, which includes the pitch angle, yaw angle, pitch angle, three-axis acceleration, and GPS position data of the unmanned vehicle; 2) Use the perception module to receive and analyze the point cloud data of the lidar to determine in real time whether there is a trench in front of the unmanned vehicle: 2-1) If there is no trench in front of the unmanned vehicle, the unmanned vehicle continues to maintain the normal maneuvering mode. The path planning module of the unmanned vehicle performs path planning in the normal maneuvering mode to determine the driving speed and driving route of the unmanned vehicle at each stage; 2-2) If there is a trench in front of the unmanned vehicle, the timing of entering the trench crossing mode is determined based on the point cloud data of the LiDAR and the position data of the unmanned vehicle; In this embodiment, a distance threshold is also provided, which is determined through calibration tests to ensure that the unmanned vehicle can cross the trench in the best state. In other words, the distance threshold is generally an empirical value, usually 1 to 2 meters.

[0019] In addition, in this embodiment, the timing of entering the trench crossing mode is determined as follows: Based on the point cloud data of the laser radar and the position data of the unmanned vehicle, the trench width and the relative position relationship between the trench and the unmanned vehicle are calculated. Then, the state management module determines whether to enter the trench crossing mode based on the position data of the unmanned vehicle and the relative position relationship between the trench and the unmanned vehicle: ① If the relative position relationship between the trench and the unmanned vehicle is not vertical, the unmanned vehicle continues to maintain the normal maneuvering mode; ② If the relative position relationship between the trench and the unmanned vehicle is vertical, the unmanned vehicle enters the trench crossing mode.

[0020] In this embodiment, the target trench is usually a trench with a straight structure, so the relative position relationship between the trench and the unmanned vehicle is a vertical relationship, that is, the body of the unmanned vehicle and the trench are perpendicular to each other. Figure 4 shown.

[0021] If the target trench is a non-linear trench, in order to keep the unmanned vehicle perpendicular to the trench and provide the necessary conditions for crossing the trench, the unmanned vehicle body and the tangent line of such trench must be perpendicular to each other, such as Figure 5 shown.

[0022] 3) When the unmanned vehicle enters the trench crossing mode, the path planning module issues a control command to slow down or stop the unmanned vehicle, and the suspension control module controls the middle wheel of the unmanned vehicle to move toward the rear axle, so that the center of gravity of the unmanned vehicle moves backward until the middle wheel moves into place; 4) The trench-crossing planning module is used to calculate the first moving distance of the unmanned vehicle forward, so that the motion control module controls the unmanned vehicle to move forward according to the first moving distance until the state management module determines that the middle wheel of the unmanned vehicle crosses the trench according to the data of the perception module and the positioning module; 5) The trench crossing planning module is used to plan the action sequence for the middle wheel to move toward the rear axle. The motion control module controls the unmanned vehicle to perform rotational braking on the middle wheel according to the planned action sequence. At the same time, the suspension control module controls the middle wheel of the unmanned vehicle to move toward the front axle according to the planned action sequence, so that the center of gravity of the unmanned vehicle moves forward until the middle wheel moves into place. 6) The trench-crossing planning module calculates the second moving distance of the unmanned vehicle forward, and enables the motion control module to control the unmanned vehicle to move forward according to the second moving distance, until the state management module determines that the rear wheels of the unmanned vehicle cross the trench based on the data of the perception module and the positioning module; 7) The trench crossing planning module controls the middle wheel to move to the middle axis position, allowing the unmanned vehicle to re-enter the normal maneuvering mode.

[0023] Several experiments have verified that the present invention can be used to control a six-wheel independently driven unmanned vehicle, which can accurately cross various types of trenches with a very low error rate.

[0024] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the protection scope of the present invention.

Claims

1. An autonomous trench crossing control system for a six-wheel independently driven unmanned vehicle, characterized in that: It includes positioning module, perception module, state management module, path planning module, trench crossing planning module, motion control interface, and suspension control interface. The positioning module is used to analyze the data of vehicle-mounted sensors such as GPS and IMU to obtain the posture data and GPS position data of the unmanned combat vehicle; The perception module is used to receive and analyze the point cloud data of the laser radar, determine in real time whether there is a trench in front of the unmanned vehicle, and calculate the width of the trench and the relative position relationship between the trench and the unmanned vehicle in combination with the posture data of the unmanned vehicle; The state management module is used to determine whether the unmanned vehicle adopts the normal maneuvering mode or the trench crossing mode as the current control mode according to the relative position relationship between the trench and the unmanned vehicle and the posture data of the unmanned vehicle; The path planning module is used for planning the driving path of the unmanned vehicle and determining the driving path and driving speed of the unmanned vehicle at each stage; The trench crossing planning module is used to determine the trench crossing action plan of the unmanned vehicle in the trench crossing mode, and calculate the suspension target state corresponding to each stage in the trench crossing action plan; The motion control module is used to calculate the control instructions of the unmanned vehicle according to the driving path planning or the trench crossing action planning, and send the control instructions to the vehicle controller; The suspension control module is used to calculate the suspension control instructions according to the suspension target states corresponding to each stage in the trench crossing action planning, and send the suspension control instructions to the suspension controller.

2. A method for controlling a six-wheel independently driven unmanned vehicle using the autonomous trench crossing control system of claim 1, characterized in that: The following steps are involved: 1) Keep the control mode of the unmanned vehicle in the normal maneuvering mode, and use the positioning module to collect the output data of the on-board sensor to obtain the position and posture data of the unmanned vehicle; 2) Use the perception module to receive and analyze the point cloud data of the lidar to determine in real time whether there is a trench in front of the unmanned vehicle: 2-1) If there is no trench in front of the unmanned vehicle, the unmanned vehicle continues to maintain the normal maneuvering mode; 2-2) If there is a trench in front of the unmanned vehicle, the timing of entering the trench crossing mode is determined based on the point cloud data of the LiDAR and the position data of the unmanned vehicle; 3) When the unmanned vehicle enters the trench crossing mode, the path planning module issues a control command to slow down the unmanned vehicle, while the suspension control module controls the middle wheel of the unmanned vehicle to move toward the rear axle, so that the center of gravity of the unmanned vehicle moves backward until the middle wheel moves into place; 4) The trench-crossing planning module is used to calculate the first moving distance of the unmanned vehicle forward, so that the motion control module controls the unmanned vehicle to move forward according to the first moving distance until the state management module determines that the middle wheel of the unmanned vehicle crosses the trench according to the data of the perception module and the positioning module; 5) The trench crossing planning module is used to plan the action sequence for the middle wheel to move toward the rear axle. The motion control module controls the unmanned vehicle to perform rotational braking on the middle wheel according to the planned action sequence. At the same time, the suspension control module controls the middle wheel of the unmanned vehicle to move toward the front axle according to the planned action sequence, so that the center of gravity of the unmanned vehicle moves forward until the middle wheel moves into place. 6) The trench-crossing planning module calculates the second moving distance of the unmanned vehicle forward, and enables the motion control module to control the unmanned vehicle to move forward according to the second moving distance, until the state management module determines that the rear wheels of the unmanned vehicle cross the trench based on the data of the perception module and the positioning module; 7) The trench crossing planning module controls the middle wheel to move to the middle axis position, allowing the unmanned vehicle to re-enter the normal maneuvering mode.

3. A method for controlling a six-wheel independently driven unmanned vehicle using the autonomous trench crossing control system of claim 1, characterized in that: The posture data includes the pitch angle, yaw angle, pitch angle, and three-axis acceleration of the unmanned vehicle.

4. A method for controlling a six-wheel independently driven unmanned vehicle using the autonomous trench crossing control system of claim 1, characterized in that: A distance threshold is set for the unmanned vehicle to determine in real time whether there is a trench ahead.

5. A method for controlling a six-wheel independently driven unmanned vehicle using the autonomous trench crossing control system of claim 1, characterized in that: The path planning module of the unmanned vehicle performs path planning in the normal maneuvering mode to determine the driving speed and driving route of the unmanned vehicle at each stage.

6. A method for controlling a six-wheel independently driven unmanned vehicle using the autonomous trench crossing control system of claim 1, characterized in that: In step 2-2), the timing of entering the trench crossing mode is determined as follows: Based on the point cloud data of the laser radar and the position data of the unmanned vehicle, the trench width and the relative position relationship between the trench and the unmanned vehicle are calculated. Then, the state management module determines whether to enter the trench crossing mode based on the position data of the unmanned vehicle and the relative position relationship between the trench and the unmanned vehicle: ① If the relative position relationship between the trench and the unmanned vehicle is not vertical, the unmanned vehicle continues to maintain the normal maneuvering mode; ② If the relative position relationship between the trench and the unmanned vehicle is vertical, the unmanned vehicle enters the trench crossing mode.

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