A method and system for underwater steering control of amphibious vehicles based on angle modules

Abstract

This invention proposes a method and system for underwater steering control of amphibious vehicles based on corner modules, belonging to the field of amphibious vehicle control technology. Based on the driver's selection, the system determines whether the amphibious vehicle is steering normally, turning in place, or crabbing in the water. When the vehicle is steering normally in the water, the steering angle of the left / right wheels is calculated based on the steering wheel angle. When the vehicle is turning in place, the wheels return to their initial state, parallel to the vehicle body. When the vehicle is crabbing, the four corner modules of the vehicle steer accordingly based on the steering wheel signal input. In normal steering mode, one wheel steers based on the calculated vehicle steering angle; in turning in place mode, the wheels on both sides of the vehicle are controlled to move forward or backward; in crabbing mode, the wheels on both sides of the vehicle steer accordingly, and the wheels on both sides are controlled to move forward or backward. This invention achieves high-precision underwater heading control by controlling the wheel steering angle and changing the direction of vehicle thrust.

Description

Technical Field

[0001] This invention belongs to the field of amphibious vehicle control technology, specifically relating to an underwater steering control method and system for amphibious vehicles based on an angle module. Background Technology

[0002] With the development of intelligent transportation and multi-environment adaptable vehicles, amphibious vehicles have been widely used in fields such as water search and rescue and environmental monitoring. Existing amphibious vehicles mostly use traditional differential drive or water jet steering control methods, which result in low control precision when navigating in water. In recent years, corner module technology has been applied to highly mobile ground platforms. For amphibious vehicles using corner modules, the propulsion direction can be changed by controlling the wheel steering angle in water, thereby generating control torque. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a method and system for underwater steering control of amphibious vehicles based on an angle module. By controlling the wheel steering angle, the direction of vehicle thrust is changed, thereby achieving high-precision underwater heading control.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] In a first aspect, the present invention provides a water steering control method for amphibious vehicles based on an angular module, which has three modes: normal water steering mode, water stationary steering mode, and water crab-like steering mode.

[0006] When the vehicle is in normal underwater steering mode, if the vehicle turns left, the left wheel changes its steering angle, changes the direction of the thrust of the left wheel, and generates a yaw torque, thus turning the vehicle to the left; if the vehicle turns right, the right wheel changes its steering angle, changes the direction of the thrust of the right wheel, and generates a yaw torque, thus turning the vehicle to the right.

[0007] When the vehicle is in the water-based stationary turning mode, the wheels are restored to their initial state, with the wheels parallel to the vehicle body. By controlling the rotation direction of the four wheels, the vehicle generates a clockwise or counterclockwise yaw torque, enabling the vehicle to turn in place in the water.

[0008] When the vehicle is in crab-like steering mode in water, the amphibious vehicle's wheels change their steering angle according to the direction of the crab-like steering. By controlling the rotation direction of the four wheels, the vehicle can achieve crab-like steering.

[0009] The underwater steering control method for amphibious vehicles based on angle modules includes the following steps:

[0010] Receive the driver's steering signal and determine the amphibious vehicle's steering needs in the water. Steering needs include normal steering, stationary steering, and crab-like steering.

[0011] Based on the steering requirements, the steering process is as follows: When the vehicle is turning normally in the water, the turning angle of each wheel is calculated based on the steering wheel angle; when the vehicle is turning in place in the water, the wheels are restored to their initial state and are parallel to the vehicle body; when the vehicle is crabbing 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 turning angle of each wheel is calculated.

[0012] Based on the steering processing results, the steering is executed as follows: When the vehicle is turning normally in the water, the steering is performed by the single wheel based on the calculated turning angle of the single wheel, thus achieving normal vehicle steering; when the vehicle is turning in place in the water, the vehicle is turned in place by controlling the forward and backward states of the wheels on both sides; when the vehicle is crabbing in the water, the vehicle is crabbing based on the calculated turning angles of each wheel and by controlling the forward and backward states of each wheel.

[0013] Optionally, during the steering process, the underwater dynamics model of the amphibious vehicle based on the corner module is constructed as follows:

[0014] ;

[0015] in, and These are longitudinal speed and lateral speed, respectively. The bow roll rate is angular velocity. For the overall vehicle quality, and The vehicles are respectively in shaft and Additional mass in the axial direction, The longitudinal fluid force acting on the vehicle body itself. The fluid lateral force is the force exerted by the vehicle body itself. The fluid torque acting on the vehicle body itself. The longitudinal force generated by the paddle wheel The lateral force generated by the paddle wheel, The yaw torque generated by the paddlewheel wheel, The longitudinal force generated by the waves, The lateral force generated by the waves, The pitching torque generated by the waves, Let be the moment of inertia of the entire vehicle about the z-axis. The additional moment of inertia of the vehicle about the z-axis; superscript This represents the differential, and the coordinate system has the vehicle's center of mass as its origin. The axis is the direction of forward movement. The x-axis points to the left, and the z-axis points upward.

[0016] Optionally, in the underwater dynamics model of the amphibious vehicle, the hydrodynamics and torques are calculated as follows:

[0017] ;

[0018] in, The resistance of a vehicle in still water. The effect of lateral velocity on longitudinal force. The effect of the coupling of lateral velocity and yaw rate on longitudinal force. The effect of the square of the bow roll velocity on the longitudinal force. The effect of bow roll acceleration on lateral force. This represents the linear effect of yaw rate on lateral force. The linear effect of lateral velocity on lateral force. This represents the nonlinear effect of the cube of the lateral velocity on the lateral force. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the lateral force is given. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the lateral force. The nonlinear effect of the cube of the bow roll velocity on the lateral force. The effect of lateral acceleration on the bow roll moment. The linear effect of lateral velocity on bow roll moment. The linear effect of bow roll rate on bow roll torque. The nonlinear effect of the cube of the lateral velocity on the bow roll moment. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the yaw moment is given. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the yaw moment is considered. This represents the nonlinear effect of the cube of the bow roll velocity on the bow roll torque.

[0019] Optionally, in the underwater dynamics model of the amphibious vehicle, the bow roll torque experienced by the entire vehicle... for:

[0020] ;

[0021] in, The propulsion force generated by the paddle wheel, This refers to the front and rear wheelbase. The turning angle of the left wheel. The turning angle of the right wheel. This refers to the wheel track.

[0022] Optionally, during the steering process, when the vehicle is steering normally in water, the turning angle of a single wheel is calculated according to the following formula. :

[0023] ;

[0024] in, Indicates the steering wheel angle. This is the proportionality coefficient.

[0025] Optionally, when performing steering, if the vehicle is turning normally in the water and 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.

[0026] Optionally, when performing the steering, if the vehicle is turning in place in the water, and the vehicle turns counterclockwise, the left wheel is in a forward state and the right wheel is in a backward state, and the vehicle generates a counterclockwise yaw torque; 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 generates a clockwise yaw torque.

[0027] Optionally, during the steering process, when the vehicle is crabbing in water, if the vehicle is crabbing on the left, the steering angle of the left front wheel and the right rear wheel is: , Turn the steering wheel Dividing by the proportionality factor, the steering angles of the left rear wheel and the right front wheel are: If the vehicle is crabbing on its right side, the steering angles of the left rear wheel and the right front wheel are: , Turn the steering wheel Dividing by the proportionality factor, the steering angles of the left front wheel and the right rear wheel are: .

[0028] Optionally, when performing the steering, if the vehicle is crabbing in the water, and if the vehicle is crabbing on the left, the left front wheel and right rear wheel are in a forward state, and the left rear wheel and right front wheel are in a backward state; if the vehicle is crabbing on the right, the left rear wheel and right front wheel are in a forward state, and the left front wheel and right rear wheel are in a backward state.

[0029] Secondly, the present invention provides an underwater steering control system for amphibious vehicles based on an angular module, comprising:

[0030] The steering requirement 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, stationary steering, and crab steering.

[0031] The steering processing module is used to perform steering processing according to steering requirements as follows: When the vehicle is turning normally in water, the steering angle of each wheel is calculated based on the steering wheel angle; when the vehicle is turning in place in water, the wheels are restored to their initial state and are parallel to the vehicle body; when the vehicle is crabbing in 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.

[0032] The steering execution module is used to execute steering as follows based on the steering processing results: When the vehicle is turning normally in water, it turns the vehicle using the wheels on one side according to the calculated turning angle of the wheels on one side; when the vehicle is turning in place in water, it turns the vehicle in place by controlling the forward and backward states of the wheels on both sides; when the vehicle is crabbing in water, it crabbing turns the vehicle by controlling the forward and backward states of each wheel according to the calculated turning angle of each wheel.

[0033] The beneficial effects of this invention are as follows: Addressing the problem of amphibious vehicles turning in water, this invention proposes an amphibious vehicle underwater steering control method based on an angle module. When the vehicle is turning normally in water, the vehicle's propulsion direction is changed by altering the left / right wheel angles, achieving left / right steering. When the vehicle is turning in place, the wheels return to their initial state, parallel to the vehicle body, and the vehicle's in-place steering is achieved by controlling the forward and backward states of the wheels on both sides. When the vehicle is crabbing in water, the crabbing steering is achieved by changing the wheel angles and controlling the forward and backward states of each wheel. This invention achieves steering by changing the wheel angles, resulting in higher control precision, while reducing additional propulsion components, lowering mechanical complexity, and reducing energy consumption. Attached Figure Description

[0034] Figure 1 This is a flowchart illustrating the underwater steering control method for amphibious vehicles based on angular modules.

[0035] Figure 2 This is a schematic diagram of the vehicle's left-turning structure based on the angle module-based underwater steering control method for amphibious vehicles.

[0036] Figure 3 This is a schematic diagram of a vehicle turning left in water using an amphibious vehicle steering control method based on an angle module.

[0037] Figure 4 This is a schematic diagram of the counterclockwise in-situ turning structure of an amphibious vehicle using an angle module-based underwater steering control method.

[0038] Figure 5 This is a schematic diagram of a vehicle performing a counterclockwise in-situ turn in water using an amphibious vehicle steering control method based on an angle module.

[0039] Figure 6 This is a schematic diagram of the left front crab steering structure of an amphibious vehicle based on an angle module underwater steering control method.

[0040] Figure 7 This is a schematic diagram of the left front crab steering of an amphibious vehicle using an underwater steering control method based on an angle module.

[0041] Figure 8 This is a schematic diagram of the underwater steering control system for an amphibious vehicle based on an angular module. Detailed Implementation

[0042] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0043] In one embodiment, the present invention proposes an underwater steering control method for amphibious vehicles based on corner modules, which has three modes: normal underwater steering mode, underwater stationary steering mode, and underwater crab-like steering mode.

[0044] The flowchart of the underwater steering control method for amphibious vehicles based on angular modules is as follows: Figure 1 As shown, it first receives the driver's steering signal and selects the vehicle steering mode.

[0045] If the amphibious vehicle's steering mode is the normal steering mode in water, when the vehicle turns left, the left wheel changes its steering angle, changes the direction of the left wheel's propulsion force, and generates a yaw torque, thus causing the vehicle to turn left; when the vehicle turns right, the right wheel changes its steering angle, changes the direction of the right wheel's propulsion force, and generates a yaw torque, thus causing the vehicle to turn right.

[0046] If the amphibious vehicle's steering mode is the water-based stationary steering mode, the wheels are restored to their initial state, with the wheels parallel to the vehicle body. By controlling the forward or backward rotation of the four wheels, the vehicle generates a yaw torque, thus enabling the vehicle to turn in place in the water.

[0047] If the amphibious vehicle's steering mode is the crab-like steering mode in water, the wheels will turn at different angles and rotate accordingly based on the vehicle's crab-like steering direction, thereby changing the direction of propulsion and achieving crab-like steering.

[0048] The underwater steering control method for amphibious vehicles based on corner modules proposed in this embodiment is as follows:

[0049] The vehicle dynamics model is constructed based on the corner module. The amphibious vehicle dynamics model is as follows:

[0050] ;

[0051] in, and These are longitudinal speed and lateral speed, respectively. The bow roll rate is angular velocity. For the overall vehicle quality, and The vehicles are respectively in shaft and Additional mass in the axial direction, The longitudinal fluid force acting on the vehicle body itself. The fluid lateral force is the force exerted by the vehicle body itself. The fluid torque acting on the vehicle body itself. The longitudinal force generated by the paddle wheel The lateral force generated by the paddle wheel, The yaw torque generated by the paddlewheel wheel, The longitudinal force generated by the waves, The lateral force generated by the waves, The pitching torque generated by the waves, Let be the moment of inertia of the entire vehicle about the z-axis. The additional moment of inertia of the vehicle about the z-axis; superscript This represents the differential, and the coordinate system has the vehicle's center of mass as its origin. The axis is the direction of forward movement. The x-axis points to the left, and the z-axis points upward.

[0052] The fluid dynamics and torque calculations are as follows:

[0053] ;

[0054] in, The resistance of a vehicle in still water. The effect of lateral velocity on longitudinal force. The effect of the coupling of lateral velocity and yaw rate on longitudinal force. The effect of the square of the bow roll velocity on the longitudinal force. The effect of bow roll acceleration on lateral force. This represents the linear effect of yaw rate on lateral force. The linear effect of lateral velocity on lateral force. This represents the nonlinear effect of the cube of the lateral velocity on the lateral force. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the lateral force is given. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the lateral force. The nonlinear effect of the cube of the bow roll velocity on the lateral force. The effect of lateral acceleration on the bow roll moment. The linear effect of lateral velocity on bow roll moment. The linear effect of bow roll rate on bow roll torque. The nonlinear effect of the cube of the lateral velocity on the bow roll moment. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the yaw moment is given. The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the yaw moment is considered. This represents the nonlinear effect of the cube of the bow roll velocity on the bow roll torque.

[0055] The longitudinal force on the vehicle body is generated by the rotation of the wheels and their interaction with the water flow, producing propulsion. The component of the force along the axial direction, the lateral force of the vehicle body is the wheel thrust along the axis. The component of force along the axial direction.

[0056] Furthermore, when an amphibious vehicle turns, the steering wheel angle... With the turning angle of the wheel The relationship is:

[0057] ;

[0058] in, The proportionality coefficient represents the wheel angle. This refers to the steering angle of the wheels when navigating in water.

[0059] The yaw moment provided by the lateral force generated by the paddle wheels for:

[0060] ;

[0061] in, The lateral force generated by the left front wheel. The lateral force generated by the left rear wheel. The lateral force generated by the right front wheel. The lateral force generated by the right rear wheel. and These are the distances from the front and rear axles to the center of mass, respectively.

[0062] Additional yaw torque provided by the longitudinal force deviation on both sides generated by the paddle wheels for:

[0063] ;

[0064] in, , , , These are the longitudinal forces generated by the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively. This refers to the wheel track.

[0065] The lateral and longitudinal forces acting on a wheel are derived from the propulsive force generated by the wheel:

[0066] ;

[0067] in, , These are the left wheel corner and the right wheel corner, respectively. The propulsion force generated for the paddle wheel.

[0068] The yaw torque generated by the paddle wheel for:

[0069] ;

[0070] Vehicle bow roll damping moment for:

[0071] ;

[0072] Therefore, the nose roll torque experienced by the entire vehicle for:

[0073] ;

[0074] in, This refers to the front and rear wheelbase. This refers to the wheel track.

[0075] The yaw moment provided by the lateral force generated by the propeller wheel and the additional yaw moment provided by the deviation of the longitudinal forces on both sides generated by the propeller wheel overcome the yaw damping moment generated by the fluid and the yaw moment generated by the waves, thereby enabling the vehicle to turn in water.

[0076] like Figure 2 and Figure 3 As shown, when the vehicle's steering mode is in the normal steering mode in water, when the vehicle turns left, the left wheel of the amphibious vehicle steers. This causes the thrust of the left front wheel to generate a leftward component, and the thrust of the left rear wheel to generate a rightward component. These two components constitute the lateral force of the wheels. The lateral forces of the two wheels generate a yaw torque, causing the amphibious vehicle to turn left. Because the left wheel is turning, the thrust of the left wheel generates a lateral component. Therefore, there is a difference in the longitudinal forces on the left and right sides of the vehicle, generating an additional yaw torque in the same direction as the torque provided by the lateral force. This allows the vehicle to complete the turn quickly, increasing the turning speed of the amphibious vehicle.

[0077] When a vehicle performs a stationary turn in a narrow waterway, the wheels return to their initial state, parallel to the vehicle body. When the vehicle performs a counter-clockwise stationary turn, the left wheel moves forward and the right wheel moves backward, creating a counter-clockwise rolling torque, enabling the vehicle to turn counter-clockwise in the water. Conversely, when the vehicle performs a clockwise stationary turn, the right wheel moves forward and the left wheel moves backward, creating a clockwise steering torque, enabling the vehicle to turn clockwise in the water.

[0078] like Figure 4 and Figure 5 As shown, when the vehicle is in water-based stationary turning mode, the four wheels of the amphibious vehicle return to their normal positions, parallel to the vehicle body. The steering direction of the wheels is controlled by turning the steering wheel. When the steering wheel is turned counterclockwise, the amphibious vehicle performs a counterclockwise stationary turn. At this time, when the driver presses the accelerator pedal, the four wheels begin to rotate. Through interaction with the water flow, they generate propulsion force, forming a yaw torque, which allows the vehicle to turn in place.

[0079] When a vehicle performs a stationary turn, the left front wheel moves forward, generating a leftward thrust; the left rear wheel moves forward, generating a rightward thrust; the right front wheel moves backward, generating a leftward thrust; and the right rear wheel moves backward, generating a rightward thrust. Therefore, when an amphibious vehicle performs a counter-clockwise stationary turn in water, the left wheel moves forward and the right wheel moves backward, creating a counter-clockwise bow roll torque, enabling the amphibious vehicle to turn counter-clockwise. When the vehicle performs a clockwise stationary turn, the right wheel moves forward and the left wheel moves backward, creating a clockwise bow roll torque, enabling the amphibious vehicle to turn clockwise.

[0080] When an amphibious vehicle performs a crab-like turn, the wheels turn at different angles depending on the direction the steering wheel is turned, resulting in different wheel rotation states. This causes the direction of the propulsive force generated by the wheels to be the same as the direction of the vehicle's crab-like turn.

[0081] like Figure 6 and Figure 7 As shown, when the vehicle is in crab-like steering mode in water, the left front wheel and right rear wheel have the same steering angle, and the left rear wheel and right front wheel have the same steering angle. For the vehicle to crab-like, the thrust on all four wheels should be in the direction of crab-like movement. When the vehicle is performing a left-front crab-like steering maneuver, the steering angles of the left front wheel and right rear wheel are... The steering angles of the left rear wheel and the right front wheel are: The left front wheel and right rear wheel should be in a forward-moving state, while the left rear wheel and right front wheel should be in a backward-moving state. Therefore, the direction of the propulsion force generated by the four wheels is the crab-like steering direction.

[0082] When a vehicle performs a left-front crab turn, the left front wheel is forward, receiving thrust towards the left front; the left rear wheel is backward, receiving thrust towards the left front; the right front wheel is backward, receiving thrust towards the left front; and the right rear wheel is forward, receiving thrust towards the left front. Therefore, when the vehicle performs a crab turn, the wheel rotation states are not entirely the same; the left front wheel and right rear wheel rotate in the same direction, and the right front wheel and left rear wheel rotate in the same direction. However, when an amphibious vehicle performs a right-front crab turn, the left rear wheel and right front wheel turn at different angles. The steering angles of the left front wheel and the right rear wheel are: With the left front wheel in a reverse position, the thrust is directed to the right front; the left rear wheel in a forward position, the thrust is directed to the right front; the right front wheel in a forward position, the thrust is directed to the right front; and the right rear wheel in a reverse position, the thrust is directed to the right front. At this time, the thrust of all four wheels of the amphibious vehicle is directed to the right front, propelling the vehicle forward to the right.

[0083] In another embodiment, the present invention proposes an amphibious vehicle underwater steering control system based on an angular module, for executing the amphibious vehicle underwater steering control method based on an angular module proposed in the foregoing embodiments.

[0084] like Figure 8 As shown, the underwater steering control system for amphibious vehicles based on corner modules includes:

[0085] Steering Requirement Module: Based on the driver's selection, determine whether the amphibious vehicle is turning normally, turning in place, or crabbing in water;

[0086] Steering processing module: Based on the driver's steering needs, when the vehicle is turning normally, the steering angle of the left / right wheels is calculated according to 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 crabbing, the steering angle of all four wheels is calculated according to the steering wheel angle.

[0087] Steering execution module: When the vehicle is turning normally, the vehicle turns according to the calculated turning angle; when the vehicle is turning in place, the vehicle turns in place in water by controlling the forward or backward movement of the wheels on both sides; when the vehicle is crabbing, the four wheels turn accordingly according to the calculated turning angle, and the vehicle crabbing turns by controlling the rotation direction of the four wheels.

[0088] The working principles and specific processes of each module in this system are the same as those of the water steering control method for amphibious vehicles based on corner modules, so they will not be repeated here.

[0089] Those skilled in the art will recognize that the units and algorithm steps of the various examples 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 implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0090] 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 falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for underwater steering control of amphibious vehicles based on angular modules, characterized in that, Includes the following steps: Receive the driver's steering signal and determine the amphibious vehicle's steering needs in the water. Steering needs include normal steering, stationary steering, and crab-like steering. Based on steering requirements, the steering process is as follows: When the vehicle is steering normally in water, the turning angle of each wheel is calculated based on the steering wheel angle; when the vehicle is turning in place in water, the wheels return to their initial state, parallel to the vehicle body; when the vehicle is crabbing in water, the left front wheel and right rear wheel rotate in the same direction, and the right front wheel and left rear wheel rotate in the same direction, and the turning angle of each wheel is calculated; during the steering process, an amphibious vehicle underwater dynamics model based on an angle module is constructed as follows: Where u and v are the longitudinal and lateral vehicle speeds, respectively, r is the yaw rate, and m is the vehicle mass. x and m y Let X represent the additional mass of the vehicle in the x-axis and y-axis directions, respectively. H For the longitudinal fluid force of the vehicle body itself, Y H N is the lateral fluid force acting on the vehicle body itself. H X is the fluid torque of the vehicle body itself. P For the longitudinal force generated by the paddle wheel, Y P The lateral force generated by the paddle wheel, N P X is the yaw torque generated by the paddlewheel. E Y represents the longitudinal force generated by the wave. E N represents the lateral force generated by the wave. E For the yaw moment generated by the waves, I z Let J be the moment of inertia of the entire vehicle about the z-axis. z The additional moment of inertia of the vehicle about the z-axis; the superscript · indicates the differential, the coordinate system is with the vehicle's center of mass as the origin, the x-axis as the forward direction, the y-axis as the leftward direction, and the z-axis as the upward direction; In the underwater dynamics model of the amphibious vehicle, the hydrodynamics and torques are calculated as follows: Where R0 is the resistance of the vehicle in still water, and X vv X represents the effect of lateral velocity on longitudinal force. vr To illustrate the effect of the coupling of lateral velocity and yaw rate on longitudinal force, X rr The effect of the square of the bow roll velocity on the longitudinal force. The effect of bow roll acceleration on lateral force, Y r As the linear effect of yaw rate on lateral force, Y v As the linear effect of lateral velocity on lateral force, Y vvv Y represents the nonlinear effect of the cube of the lateral velocity on the lateral force. vvr To represent the nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the lateral force, Y vrr The nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the lateral force, Y rrr The nonlinear effect of the cube of the bow roll velocity on the lateral force. The effect of lateral acceleration on the bow roll moment, N v To represent the linear effect of lateral velocity on the bow roll moment, N r N represents the linear effect of the bow roll rate on the bow roll torque. vvv N represents the nonlinear effect of the cube of the lateral velocity on the yaw moment. vvr N represents the nonlinear effect of the coupling of the square of the lateral velocity and the yaw rate on the yaw moment. vrr N represents the nonlinear effect of the coupling of the squares of the lateral velocity and the yaw rate on the yaw moment. rrr The nonlinear effect of the cube of the bow roll velocity on the bow roll torque; Based on the steering processing results, the steering is executed as follows: When the vehicle is turning normally in the water, the steering is performed by the single wheel based on the calculated turning angle of the single wheel, thus achieving normal vehicle steering; when the vehicle is turning in place in the water, the vehicle is turned in place by controlling the forward and backward states of the wheels on both sides; when the vehicle is crabbing in the water, the vehicle is crabbing based on the calculated turning angles of each wheel and by controlling the forward and backward states of each wheel.

2. The underwater steering control method for amphibious vehicles based on angle modules as described in claim 1, characterized in that: In the underwater dynamics model of the amphibious vehicle, the yaw moment N experienced by the entire vehicle is: N=T·L·sinδ l -T·L·sinδ r -T·B·cosδ l +T·B·cosδ r +(N H +N E ); Where T is the propulsion force generated by the paddle wheel, L is the front and rear wheelbase, and δ l The turning angle of the left wheel is δ. r B is the turning angle of the right wheel, and B is the track width.

3. The underwater steering control method for amphibious vehicles based on angle modules as described in claim 1, characterized in that: During the steering process, when the vehicle is steering normally in water, the single-wheel steering angle δ is calculated according to the following formula: Where, δ SW Indicates the steering wheel angle, i SW This is the proportionality coefficient.

4. The underwater steering control method for amphibious vehicles based on angle modules as described in claim 3, characterized in that: When performing steering, if the vehicle is turning normally in water and turns left, the left wheel rotates according to the wheel angle, and the lateral forces of the left front wheel and left rear wheel generate a yaw moment, while the longitudinal forces of the left wheel and right wheel generate an additional yaw moment. If the vehicle turns right, the right wheel rotates according to the wheel angle, and the lateral forces of the right front wheel and right rear wheel generate a yaw moment, while the longitudinal forces of the left wheel and right wheel generate an additional yaw moment.

5. The underwater steering control method for amphibious vehicles based on angle modules as described in claim 1, characterized in that: When performing a steering maneuver, if the vehicle is turning in place while in water, and it turns counterclockwise, the left wheel moves forward and the right wheel moves backward, creating a counterclockwise yaw torque. If the vehicle turns clockwise, the right wheel moves forward and the left wheel moves backward, creating a clockwise yaw torque.

6. The underwater steering control method for amphibious vehicles based on angle modules as described in claim 1, characterized in that: During the steering process, when the vehicle is crabbing in water, if the vehicle is crabbing on the left, the steering angle of the left front wheel and the right rear wheel is δ. xl δ xl By steering wheel angle δ SW Dividing by the proportionality coefficient, the steering angles of the left rear wheel and the right front wheel are π-δ. xl If the vehicle is crabbing on its right side, the steering angle of the left rear wheel and the right front wheel is δ. xr δ xr By steering wheel angle δ SW Dividing by the proportionality coefficient, the steering angles of the left front wheel and the right rear wheel are π-δ. xr .

7. The underwater steering control method for amphibious vehicles based on angle modules as described in claim 6, characterized in that: When performing the steering maneuver, if the vehicle is crabbing in the water, the left front wheel and right rear wheel are moving forward, and the left rear wheel and right front wheel are moving backward; if the vehicle is crabbing on the right side, the left rear wheel and right front wheel are moving forward, and the left front wheel and right rear wheel are moving backward.

8. An amphibious vehicle underwater steering control system based on an angular module, used to implement the method as described in any one of claims 1-7, characterized in that, include: The steering requirement 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, stationary steering, and crab steering. The steering processing module is used to perform steering processing according to steering requirements as follows: When the vehicle is turning normally in water, the steering angle of each wheel is calculated based on the steering wheel angle; when the vehicle is turning in place in water, the wheels are restored to their initial state and are parallel to the vehicle body; when the vehicle is crabbing in 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 as follows based on the steering processing results: When the vehicle is turning normally in water, it turns the vehicle using the wheels on one side according to the calculated turning angle of the wheels on one side; when the vehicle is turning in place in water, it turns the vehicle in place by controlling the forward and backward states of the wheels on both sides; when the vehicle is crabbing in water, it crabbing turns the vehicle by controlling the forward and backward states of each wheel according to the calculated turning angle of each wheel.

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