Amphibious vehicle underwater steering control method and system based on angle module

Abstract

The invention provides an amphibious vehicle underwater steering control method and system based on an angle module, and belongs to the technical field of amphibious vehicle control. According to the selection of a driver, the amphibious vehicle is judged to be in normal steering, pivot steering and crab steering in water; when the vehicle normally steers in water, left / right side wheel turning angles are calculated according to the steering wheel turning angle; when the vehicle is in pivot steering in water, the wheels recover to the initial state and are parallel to the vehicle body; when the vehicle is in crab-shaped steering in water, the four corner modules of the vehicle conduct corresponding steering according to steering wheel signal input. In the normal steering mode, according to the calculated steering angle of the vehicle, wheels on one side steer; in the pivot steering mode, wheels on the two sides of the vehicle are controlled to move forwards or backwards; according to the crab steering mode, wheels on the two sides of the vehicle conduct corresponding steering, and the wheels on the two sides are controlled to move forwards or backwards. By controlling the steering angle of the wheels, the thrust direction of the vehicle is changed, and high-precision underwater course control is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of amphibious vehicle control, and in particular relates to an amphibious vehicle underwater steering control method and system based on a corner module. Background Art

[0002] With the development of intelligent transportation and multi-environmental vehicles, amphibious vehicles have been widely used in fields such as water search and rescue and environmental monitoring. Existing amphibious vehicles often use traditional steering methods such as differential drive or water jet steering, which results in limited control accuracy while underwater. In recent years, corner module technology has been applied to high-mobility ground platforms. For amphibious vehicles using corner modules, the propulsion direction can be changed in water by controlling the wheel steering angle, thereby generating a control torque. Summary of the Invention

[0003] In response to the deficiencies in the prior art, the present invention provides an amphibious vehicle underwater steering control method and system based on an angle module, which achieves high-precision underwater heading control by controlling the wheel steering angle and changing the vehicle thrust direction.

[0004] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides an underwater steering control method for an amphibious vehicle based on a corner module, which has three modes: a normal underwater steering mode, an in-place underwater steering mode, and a crab-like underwater steering mode.

[0005] When the vehicle is in normal steering mode in water, if the vehicle turns left, the left wheel changes the steering angle, changes the thrust direction of the left wheel, and generates a yaw torque, thereby turning the vehicle to the left; if the vehicle turns right, the right wheel changes the steering angle, changes the thrust direction of the right wheel, and generates a yaw torque, thereby turning the vehicle to the right.

[0006] When the vehicle is in the water turning mode, the wheels are restored to the initial state, the wheels are parallel to the body, and by controlling the rotation direction of the four wheels, the vehicle generates a clockwise or counterclockwise pitch torque, thereby achieving the vehicle turning in place in the water.

[0007] When the vehicle performs the underwater crab steering mode, the wheels of the amphibious vehicle change the steering angle according to the crab steering direction of the vehicle, and the vehicle crab steering is achieved by controlling the rotation direction of the four wheels.

[0008] The underwater steering control method of an amphibious vehicle based on a corner module comprises the following steps: Receive the driver's steering signal and determine the steering requirements of the amphibious vehicle in the water, including normal steering, on-the-spot steering and crab steering; Based on the steering requirements, the steering process is as follows: when the vehicle is turning normally in the water, the wheel angle on one side is calculated based on the steering wheel angle; when the vehicle is turning in place in the water, the wheels return to their initial state and are parallel to the vehicle body; when the vehicle is turning crab-style in the water, the left front wheel and the right rear wheel rotate in the same direction, and the right front wheel and the left rear wheel rotate in the same direction, and the wheel angles of each wheel are calculated; According to the steering processing results, steering is performed as follows: when the vehicle is turning normally in the water, the single-side wheel is steered according to the calculated single-side wheel angle to achieve normal steering of the vehicle; when the vehicle is turning in place in the water, the forward and backward states of the wheels on both sides of the vehicle are controlled to achieve on-site steering of the vehicle; when the vehicle is turning in crab mode in the water, the crab mode is achieved by controlling the forward and backward states of each wheel according to the calculated wheel angle.

[0009] Optionally, during the steering process, an amphibious vehicle underwater dynamics model based on an angle module is constructed as follows: ; in, and are the longitudinal speed and lateral speed, is the yaw angular velocity, is the vehicle mass, and For vehicles in Axis and Additional mass in the axial direction, is the longitudinal force of the fluid on the vehicle body, is the lateral force of the fluid on the vehicle body, is the fluid torque on the vehicle body, is the longitudinal force generated by the paddle wheel, is the lateral force generated by the paddle wheel, is the yaw moment generated by the paddle wheel, is the longitudinal force generated by the wave, is the lateral force generated by the waves, is the yaw moment generated by waves, is the moment of inertia of the vehicle around the z-axis, is the additional moment of inertia of the vehicle around the z axis; represents the differential, and the coordinate system takes the center of mass of the vehicle as the origin. Axis is the forward direction, The a-axis is to the left, and the z-axis is to the upward direction.

[0010] Optionally, in the underwater dynamics model of the amphibious vehicle, the calculation of fluid power and torque is as follows: ; in, is the drag of the vehicle in still water, is the effect of lateral velocity on longitudinal force, is the effect of the coupling of lateral velocity and yaw angular velocity on the longitudinal force, is the effect of the square of the yaw angular velocity on the longitudinal force, is the effect of the yaw angular acceleration on the lateral force, is the linear effect of yaw rate on lateral force, is the linear effect of lateral velocity on lateral force, is the nonlinear effect of the cube of the lateral velocity on the lateral force, is the nonlinear effect of the coupling of the square of the lateral velocity and the yaw angular velocity on the lateral force, is the nonlinear effect of the coupling of lateral velocity and square of yaw angular velocity on lateral force, is the nonlinear effect of the cubic power of the yaw angular velocity on the lateral force, is the effect of lateral acceleration on the yaw moment, is the linear effect of lateral speed on yaw moment, is the linear effect of the yaw angular velocity on the yaw moment, is the nonlinear effect of the cube of the lateral velocity on the yaw moment, is the nonlinear effect of the coupling of the square of the lateral velocity and the yaw angular velocity on the yaw moment, is the nonlinear effect of the coupling of lateral velocity and square of yaw angular velocity on yaw moment, is the nonlinear effect of the cube of the yaw angular velocity on the yaw moment.

[0011] Optionally, in the amphibious vehicle underwater dynamics model, the pitch moment of the vehicle is for: ; in, The propulsion force generated by the paddle wheels, is the front and rear wheelbase, is the left wheel angle, is the right wheel turning angle, For wheelbase.

[0012] Optionally, during the steering process, when the vehicle is turning normally in water, the unilateral wheel angle is calculated according to the following formula: : ; in, Indicates the steering wheel angle, is the proportional coefficient.

[0013] Optionally, when the steering is performed, when the vehicle is turning normally in the water, if the vehicle turns to the left, the left wheel rotates according to the wheel angle, the lateral force of the left front wheel and the left rear wheel generates a yaw moment, and the longitudinal force of the left wheel and the longitudinal force of the right wheel generate an additional yaw moment; if the vehicle turns to the right, the right wheel rotates according to the wheel angle, the lateral force of the right front wheel and the right rear wheel generates a yaw moment, and the longitudinal force of the left wheel and the longitudinal force of the right wheel generate an additional yaw moment.

[0014] Optionally, when the steering is performed, when the vehicle is turning in place in the water, if the vehicle turns counterclockwise in place, the left wheel is in a forward state and the right wheel is in a backward state, and the vehicle forms a counterclockwise yaw moment; if the vehicle turns clockwise in place, the right wheel is in a forward state and the left wheel is in a backward state, and the vehicle forms a clockwise yaw moment.

[0015] Optionally, during the steering process, when the vehicle is crab-steering in water, if the vehicle crab-steering on the left side, the steering angles of the left front wheel and the right rear wheel are , By steering wheel angle Divided by the proportional coefficient, the steering angles of the left rear wheel and the right front wheel are ; If the vehicle crabs on the right side, the steering angles of the left rear wheel and the right front wheel are , By steering wheel angle Divided by the proportional coefficient, the steering angles of the left front wheel and the right rear wheel are .

[0016] Optionally, when the steering is performed, when the vehicle is crab-steering in the water, if the vehicle is crab-steering on the left side, the left front wheel and the right rear wheel are in a forward state, and the left rear wheel and the right front wheel are in a backward state; if the vehicle is crab-steering on the right side, the left rear wheel and the right front wheel are in a forward state, and the left front wheel and the right rear wheel are in a backward state.

[0017] In a second aspect, the present invention provides an amphibious vehicle underwater steering control system based on a corner module, comprising: A steering demand module is used to receive the driver's steering signal and determine the steering requirements of the amphibious vehicle in the water. The steering requirements include normal steering, on-the-spot steering, and crab steering. The steering processing module is used to perform steering processing according to the steering requirements as follows: when the vehicle is turning normally in the water, the single-side wheel angle is calculated based on the steering wheel angle; when the vehicle is turning in place in the water, the wheels return to their initial state and are parallel to the vehicle body; when the vehicle is turning crab-like in the water, the left front wheel and the right rear wheel rotate in the same direction, and the right front wheel and the left rear wheel rotate in the same direction, and the steering angle of each wheel is calculated; The steering execution module is used to execute steering according to the steering processing result as follows: when the vehicle is turning normally in the water, the single-side wheel is steered according to the calculated single-side wheel angle to achieve normal steering of the vehicle; when the vehicle is turning in place in the water, the forward and backward states of the wheels on both sides of the vehicle are controlled to achieve on-site steering of the vehicle; when the vehicle is turning in crab mode in the water, the crab mode is achieved by controlling the forward and backward states of each wheel according to the calculated wheel angle.

[0018] The beneficial effects of the present invention are as follows: The present invention addresses the problem of amphibious vehicles turning in water and proposes an amphibious vehicle underwater steering control method based on an angle module. When the vehicle is turning normally in water, the left / right wheel angle is changed to change the vehicle's propulsion direction, thereby achieving left / right steering. When the vehicle is turning in place in water, the wheels return to their initial state, parallel to the vehicle body, and the forward and reverse states of the wheels on both sides of the vehicle are controlled to achieve the vehicle's in-place steering. When the vehicle is turning in water in a crab-like manner, the crab-like steering is achieved by changing the wheel angle and controlling the forward and reverse states of each wheel. The present invention achieves steering by changing the wheel angle, resulting in higher control accuracy, while reducing additional propulsion components, reducing mechanical complexity, and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of the underwater steering control method of an amphibious vehicle based on an angle module.

[0020] Figure 2 The diagram shows the left-turn structure of an amphibious vehicle in water steering control method based on a corner module.

[0021] Figure 3 Schematic diagram of vehicle left turn for an amphibious vehicle in underwater steering control method based on angle module.

[0022] Figure 4 The diagram is a structural diagram of the vehicle's counterclockwise in-situ steering according to the underwater steering control method for an amphibious vehicle based on a corner module.

[0023] Figure 5 The diagram shows a counterclockwise in-situ steering method for an amphibious vehicle based on an angle module.

[0024] Figure 6 This is a schematic diagram of the vehicle's left front crab steering structure for an amphibious vehicle's underwater steering control method based on a corner module.

[0025] Figure 7 Schematic diagram of the left front crab steering of an amphibious vehicle in the water steering control method based on the corner module.

[0026] Figure 8 This is a schematic diagram of the structure of the underwater steering control system for amphibious vehicles based on corner modules. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0028] In one embodiment, the present invention proposes an underwater steering control method for an amphibious vehicle based on a corner module, which has three modes: a normal underwater steering mode, an in-situ underwater steering mode, and a crab-like underwater steering mode.

[0029] The process of the underwater steering control method of amphibious vehicles based on the corner module is as follows: Figure 1 As shown, firstly, the driver's steering signal is received and the vehicle steering mode is selected.

[0030] If the steering mode of the amphibious vehicle is the normal steering mode in water, when the vehicle turns left, the left wheel changes the steering angle, changes the direction of the propulsion force of the left wheel, generates a yaw torque, and thus turns the vehicle to the left; when the vehicle turns right, the right wheel changes the steering angle, and the propulsion force of the right wheel changes direction, generates a yaw torque, and thus turns the vehicle to the right.

[0031] If the steering mode of the amphibious vehicle is the in-water in-place steering mode, restore the wheels to their initial state, with the wheels parallel to the vehicle body, and control the four wheels to rotate forward or backward to generate a yaw torque, thereby achieving in-place steering of the vehicle in the water.

[0032] If the steering mode of the amphibious vehicle is the underwater crab steering mode, the wheels are turned to different angles according to the crab steering direction of the vehicle and rotate accordingly to change the direction of the propulsion force and realize the crab steering of the vehicle.

[0033] The underwater steering control method for an amphibious vehicle based on a corner module proposed in this embodiment is as follows: Construct a vehicle dynamics model. The amphibious vehicle dynamics model based on the corner module is: ; in, and are the longitudinal speed and lateral speed, is the yaw angular velocity, is the vehicle mass, and For vehicles in Axis and Additional mass in the axial direction, is the longitudinal force of the fluid on the vehicle body, is the lateral force of the fluid on the vehicle body, is the fluid torque on the vehicle body, is the longitudinal force generated by the paddle wheel, is the lateral force generated by the paddle wheel, is the yaw moment generated by the paddle wheel, is the longitudinal force generated by the wave, is the lateral force generated by the wave, is the yaw moment generated by waves, is the moment of inertia of the vehicle around the z-axis, is the additional moment of inertia of the vehicle around the z axis; represents the differential, and the coordinate system takes the center of mass of the vehicle as the origin. Axis is the forward direction, The a-axis is to the left, and the z-axis is to the upward direction.

[0034] The fluid forces and moments are calculated as follows: ; in, is the drag of the vehicle in still water, is the effect of lateral velocity on longitudinal force, is the effect of the coupling of lateral velocity and yaw angular velocity on the longitudinal force, is the effect of the square of the yaw angular velocity on the longitudinal force, is the effect of the yaw angular acceleration on the lateral force, is the linear effect of yaw rate on lateral force, is the linear effect of lateral velocity on lateral force, is the nonlinear effect of the cube of the lateral velocity on the lateral force, is the nonlinear effect of the coupling of the square of the lateral velocity and the yaw angular velocity on the lateral force, is the nonlinear effect of the coupling of lateral velocity and square of yaw angular velocity on lateral force, is the nonlinear effect of the cubic power of the yaw angular velocity on the lateral force, is the effect of lateral acceleration on the yaw moment, is the linear effect of lateral speed on yaw moment, is the linear effect of the yaw angular velocity on the yaw moment, is the nonlinear effect of the cube of the lateral velocity on the yaw moment, is the nonlinear effect of the coupling of the square of the lateral velocity and the yaw angular velocity on the yaw moment, is the nonlinear effect of the coupling of lateral velocity and square of yaw angular velocity on yaw moment, is the nonlinear effect of the cube of the yaw angular velocity on the yaw moment.

[0035] The longitudinal force of the vehicle body is the rotation of the wheels, which interacts with the water flow to generate propulsion. The lateral force of the vehicle body is the component of the force in the axial direction, and the lateral force of the vehicle body is the component of the force in the axial direction. Component of force in the axial direction.

[0036] Furthermore, when the amphibious vehicle turns, the steering wheel angle Wheel angle The relationship is: ; in, is the proportional coefficient, the wheel angle It is the steering angle of the wheel when sailing in water.

[0037] The yaw moment provided by the lateral force generated by the paddle wheels for: ; in, is the lateral force generated by the left front wheel, is the lateral force generated by the left rear wheel, is the lateral force generated by the right front wheel, is the lateral force generated by the right rear wheel, and are the distances from the front and rear axles to the center of mass, respectively.

[0038] Additional yaw moment provided by the longitudinal force deviation on both sides generated by the paddle wheels for: ; in, 、 、 、 are the longitudinal forces generated by the left front wheel, right front wheel, left rear wheel, and right rear wheel respectively. For wheelbase.

[0039] The lateral and longitudinal forces acting on the wheels are obtained from the propulsive forces generated by the wheels: ; in, 、 They are the left wheel angle and the right wheel angle respectively. Propulsion generated by the paddle wheels.

[0040] Yawing moment generated by paddle wheels for: ; Vehicle yaw damping torque for: ; Therefore, the yaw moment of the vehicle is for: ; in, is the front and rear wheelbase, For wheelbase.

[0041] The yaw moment provided by the lateral force generated by the paddle wheels and the additional yaw moment provided by the longitudinal force deviation on both sides generated by the paddle wheels overcome the yaw damping moment generated by the fluid and the yaw moment generated by the waves, thereby enabling the vehicle to turn in the water.

[0042] like Figure 2 and Figure 3 As shown, when the vehicle's steering mode is in the normal underwater steering mode, the vehicle turns left, and the left wheel of the amphibious vehicle steers. As a result, the propulsion force of the left front wheel generates a leftward component, and the propulsion force of the left rear wheel generates a rightward component. These two components constitute the wheel lateral force. These lateral forces generate a pitching moment, causing the amphibious vehicle to steer left. Because the left wheel is turning and the propulsion force of the left wheel generates a lateral component, there is a difference in longitudinal force between the left and right sides of the vehicle, generating an additional pitching moment in the same direction as the torque provided by the lateral force. This enables the vehicle to complete the turn quickly, increasing the turning speed of the amphibious vehicle.

[0043] When the vehicle makes a pivot turn in a narrow waterway, the wheels return to their initial position, parallel to the vehicle body. When the vehicle makes a counterclockwise pivot turn, the left wheel moves forward and the right wheel moves backward, creating a counterclockwise pitching moment and enabling the vehicle to pivot counterclockwise in the water. When the vehicle makes a clockwise pivot turn, the right wheel moves forward and the left wheel moves backward, creating a clockwise steering moment and enabling the vehicle to pivot clockwise in the water.

[0044] like Figure 4 and Figure 5 As shown in the figure, when the vehicle is in underwater in-situ steering mode, the four wheels of the amphibious vehicle return to their normal position, parallel to the vehicle body. The steering direction is controlled by turning the steering wheel. When the steering wheel is turned counterclockwise, the amphibious vehicle performs a counterclockwise in-situ steering. At this time, when the driver presses the accelerator pedal, the four wheels begin to rotate. By interacting with the water flow, they generate propulsion force, forming a yaw torque, which causes the vehicle to turn in-situ.

[0045] When the vehicle performs a pivot turn, the left front wheel is in forward motion, generating leftward thrust; the left rear wheel is in forward motion, generating rightward thrust; the right front wheel is in reverse motion, generating leftward thrust; and the right rear wheel is in reverse motion, generating rightward thrust. Therefore, when an amphibious vehicle performs a counterclockwise pivot turn in water, the left wheel is in forward motion and the right wheel is in reverse motion, generating a counterclockwise pitch moment, enabling the vehicle to achieve a counterclockwise pivot turn. When the vehicle performs a clockwise pivot turn, the right wheel is in forward motion and the left wheel is in reverse motion, generating a clockwise pitch moment, enabling the vehicle to achieve a clockwise pivot turn.

[0046] When an amphibious vehicle performs a crab turn, the wheels turn to different angles and in different wheel rotation states according to the direction of the steering wheel rotation, so that the direction of the propulsion force generated by the wheels is the same as the crab turn direction of the vehicle.

[0047] like Figure 6 and Figure 7 As shown in the figure, when the vehicle is in crab steering mode, the steering angles of the left front wheel and the right rear wheel are the same, and the steering angles of the left rear wheel and the right front wheel are the same. In order to make the vehicle crab, the thrust on the four wheels should be in the crab direction. When the vehicle performs left front crab steering, the steering angles of the left front wheel and the right rear wheel are , the steering angles of the left rear wheel and the right front wheel are , the left front wheel and the right rear wheel should be in the forward state, while the left rear wheel and the right front wheel should be in the backward state. Therefore, the direction of the propulsion force generated by the four wheels is the crab steering direction.

[0048] When the vehicle performs a left front crab turn, the left front wheel is in a forward state and the thrust direction is the left front; the left rear wheel is in a backward state and the thrust direction is the left front; the right front wheel is in a backward state and the thrust direction is the left front; the right rear wheel is in a forward state and the thrust direction is the left front. Therefore, when the vehicle performs a crab turn, the wheel rotation state is not exactly the same. The left front wheel and the right rear wheel rotate in the same state, and the right front wheel and the left rear wheel rotate in the same state. When the amphibious vehicle performs a right front crab turn, the steering angles of the left rear wheel and the right front wheel are , the steering angles of the left front wheel and the right rear wheel are , the left front wheel is in the backward state, and the thrust direction it receives is to the right front; the left rear wheel is in the forward state, and the thrust direction it receives is to the right front; the right front wheel is in the forward state, and the thrust direction it receives is to the right front; the right rear wheel is in the backward state, and the thrust direction it receives is to the right front. At this time, the thrust direction of the four wheels of the amphibious vehicle is to the right front, pushing the vehicle to move toward the right front.

[0049] In another embodiment, the present invention proposes an amphibious vehicle underwater steering control system based on a corner module, which is used to execute the amphibious vehicle underwater steering control method based on a corner module proposed in the above embodiment.

[0050] like Figure 8 As shown, the underwater steering control system of an amphibious vehicle based on the corner module includes: Steering requirement module: determines whether the amphibious vehicle is turning normally, turning on the spot, or turning crab-like in water according to the driver's selection; Steering processing module: Based on the driver's steering requirements, when the vehicle is turning normally, the left / right wheel angles are calculated based on the steering wheel angle; when the vehicle is turning in place, the wheels return to their initial state and are parallel to the vehicle body; when the vehicle is turning in a crab manner, the steering angles of the four wheels are calculated based on the steering wheel angle; Steering execution module: When the vehicle is turning normally, the vehicle turns according to the calculated vehicle turning angle; when the vehicle is turning in place, turning in place in the water is achieved by controlling the wheels on both sides of the vehicle to move forward or backward; when the vehicle is turning in a crab manner, the four wheels turn accordingly according to the calculated steering angle, and the vehicle crab manner is achieved by controlling the rotation direction of the four wheels.

[0051] In this system, the working principles and specific processes of each module are the same as the steps of the underwater steering control method of amphibious vehicles based on the corner module, so they will not be repeated here.

[0052] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0053] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for controlling underwater steering of an amphibious vehicle based on an angle module, characterized in that: The steps include: Receive the driver's steering signal and determine the steering requirements of the amphibious vehicle in the water, including normal steering, on-the-spot steering and crab steering; Based on the steering requirements, the steering process is as follows: when the vehicle is turning normally in the water, the wheel angle on one side is calculated based on the steering wheel angle; when the vehicle is turning in place in the water, the wheels return to their initial state and are parallel to the vehicle body; when the vehicle is turning crab-style in the water, the left front wheel and the right rear wheel rotate in the same direction, and the right front wheel and the left rear wheel rotate in the same direction, and the wheel angles of each wheel are calculated; According to the steering processing results, steering is performed as follows: when the vehicle is turning normally in the water, the single-side wheel is steered according to the calculated single-side wheel angle to achieve normal steering of the vehicle; when the vehicle is turning in place in the water, the forward and backward states of the wheels on both sides of the vehicle are controlled to achieve on-site steering of the vehicle; when the vehicle is turning in crab mode in the water, the crab mode is achieved by controlling the forward and backward states of each wheel according to the calculated wheel angle.

2. The method for controlling underwater steering of an amphibious vehicle based on a corner module according to claim 1, wherein: During the steering process, the underwater dynamics model of the amphibious vehicle based on the angle module is constructed as follows: ； in, and are the longitudinal speed and lateral speed, is the yaw angular velocity, is the vehicle mass, and For vehicles in Axis and Additional mass in the axial direction, is the longitudinal force of the fluid on the vehicle body, is the lateral force of the fluid on the vehicle body, is the fluid torque on the vehicle body, is the longitudinal force generated by the paddle wheel, is the lateral force generated by the paddle wheel, is the yaw moment generated by the paddle wheel, is the longitudinal force generated by the wave, is the lateral force generated by the wave, is the yaw moment generated by waves, is the moment of inertia of the vehicle around the z-axis, is the additional moment of inertia of the vehicle around the z axis; represents the differential, and the coordinate system takes the center of mass of the vehicle as the origin. Axis is the forward direction, The a-axis is to the left, and the z-axis is to the upward direction.

3. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 2, characterized in that: In the underwater dynamics model of the amphibious vehicle, the calculation of fluid power and torque is as follows: ； in, is the drag of the vehicle in still water, is the effect of lateral velocity on longitudinal force, is the effect of the coupling of lateral velocity and yaw angular velocity on the longitudinal force, is the effect of the square of the yaw angular velocity on the longitudinal force, is the effect of the yaw angular acceleration on the lateral force, is the linear effect of yaw rate on lateral force, is the linear effect of lateral velocity on lateral force, is the nonlinear effect of the cube of the lateral velocity on the lateral force, is the nonlinear effect of the coupling of the square of the lateral velocity and the yaw angular velocity on the lateral force, is the nonlinear effect of the coupling of lateral velocity and square of yaw angular velocity on lateral force, is the nonlinear effect of the cubic power of the yaw angular velocity on the lateral force, is the effect of lateral acceleration on the yaw moment, is the linear effect of lateral speed on yaw moment, is the linear effect of the yaw angular velocity on the yaw moment, is the nonlinear effect of the cube of the lateral velocity on the yaw moment, is the nonlinear effect of the coupling of the square of the lateral velocity and the yaw angular velocity on the yaw moment, is the nonlinear effect of the coupling of lateral velocity and square of yaw angular velocity on yaw moment, is the nonlinear effect of the cube of the yaw angular velocity on the yaw moment.

4. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 2, characterized in that: In the underwater dynamics model of the amphibious vehicle, the pitch moment of the vehicle is for: ； in, The propulsion force generated by the paddle wheels, is the front and rear wheelbase, is the left wheel angle, is the right wheel turning angle, For wheelbase.

5. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 1, characterized in that: During the steering process, when the vehicle is turning normally in water, the unilateral wheel angle is calculated according to the following formula: : ； in, Indicates the steering wheel angle, is the proportional coefficient.

6. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 5, characterized in that: During the steering operation, when the vehicle is turning normally in the water, if the vehicle turns left, the left wheel rotates according to the wheel angle, the lateral force of the left front wheel and the left rear wheel generates a yaw moment, and the longitudinal force of the left wheel and the longitudinal force of the right wheel generate an additional yaw moment; if the vehicle turns right, the right wheel rotates according to the wheel angle, the lateral force of the right front wheel and the right rear wheel generates a yaw moment, and the longitudinal force of the left wheel and the longitudinal force of the right wheel generate an additional yaw moment.

7. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 1, characterized in that: During the steering operation, when the vehicle is turning in place in the water, if the vehicle turns counterclockwise, the left wheel is in a forward state and the right wheel is in a backward state, and the vehicle forms a counterclockwise yaw moment; if the vehicle turns clockwise, the right wheel is in a forward state and the left wheel is in a backward state, and the vehicle forms a clockwise yaw moment.

8. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 1, characterized in that: During the steering process, when the vehicle is crab-steering in the water, if the vehicle crab-steering on the left side, the steering angles of the left front wheel and the right rear wheel are , By steering wheel angle Divided by the proportional coefficient, the steering angles of the left rear wheel and the right front wheel are ; If the vehicle crabs on the right side, the steering angles of the left rear wheel and the right front wheel are , By steering wheel angle Divided by the proportional coefficient, the steering angles of the left front wheel and the right rear wheel are .

9. The underwater steering control method for an amphibious vehicle based on a corner module according to claim 8, characterized in that: During the steering operation, when the vehicle is crab-steering in the water, if the vehicle is crab-steering on the left side, the left front wheel and the right rear wheel are in a forward state, and the left rear wheel and the right front wheel are in a backward state; if the vehicle is crab-steering on the right side, the left rear wheel and the right front wheel are in a forward state, and the left front wheel and the right rear wheel are in a backward state.

10. An amphibious vehicle underwater steering control system based on an angle module, characterized in that: include: A steering demand module is used to receive the driver's steering signal and determine the steering requirements of the amphibious vehicle in the water. The steering requirements include normal steering, on-the-spot steering, and crab steering. The steering processing module is used to perform steering processing according to the steering requirements as follows: when the vehicle is turning normally in the water, the single-side wheel angle is calculated based on the steering wheel angle; when the vehicle is turning in place in the water, the wheels return to their initial state and are parallel to the vehicle body; when the vehicle is turning crab-like in the water, the left front wheel and the right rear wheel rotate in the same direction, and the right front wheel and the left rear wheel rotate in the same direction, and the steering angle of each wheel is calculated; The steering execution module is used to execute steering according to the steering processing result as follows: when the vehicle is turning normally in the water, the single-side wheel is steered according to the calculated single-side wheel angle to achieve normal steering of the vehicle; when the vehicle is turning in place in the water, the forward and backward states of the wheels on both sides of the vehicle are controlled to achieve on-site steering of the vehicle; when the vehicle is turning in crab mode in the water, the crab mode is achieved by controlling the forward and backward states of each wheel according to the calculated wheel angle.

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