A method for modeling the crawling modal dynamics of an amphibious robot

Abstract

The application relates to a crawling mode dynamics modeling method of an amphibious robot, and belongs to the technical field of amphibious robots, and solves the problem that robots are difficult to effectively play a role in complex building spaces in the prior art. The steps of the application comprise the following steps: step 1, kinematic analysis is carried out on a single driving claw, and a kinematic model of the driving claw is established; and step 2, the overall movement of the crawling mode is analyzed, and a kinematic model of the amphibious robot is established. Through dynamics modeling analysis on the crawling mode of the amphibious robot, the mechanical properties and operation process of the amphibious robot in the crawling mode are clarified, so that the amphibious robot can adapt to all-around operation and use in complex spaces such as buildings and underground spaces.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of amphibious robots, in particular to a crawling mode dynamics modeling method of an amphibious robot. BACKGROUND

[0002] The moving mechanism of the robot is mainly divided into wheel type, leg type and track type and wing type mechanism. The wheel type mechanism has high moving speed and high efficiency, but poor obstacle crossing ability; the leg type mechanism has flexible action, but low walking efficiency, unstable center of gravity and complex control; the wing type mechanism has fast action speed and good obstacle avoidance effect, but complex control and poor stability. How to combine the advantages of these motion form mechanisms to enhance the environmental adaptability and motion performance of the robot is a research hotspot.

[0003] Currently, three-mode robots are very rare, and the commonly seen is a wheel-leg type amphibious robot. The foldable wheel-leg type mechanism structure and control are complicated, and the wheel-leg form switching speed is slow. The wheel type mechanism and the leg type mechanism are often simply superimposed. Because of the difficulty in control, the flight mechanism is rarely combined in the wheel-leg robot.

[0004] The existing amphibious robot configuration cannot meet many performance and functional requirements, and has the following disadvantages when applied in complex urban building space: the existing amphibious robot mainly adopts a simple combination of a ground mobile platform and a rotary-wing aircraft, which leads to that different motion modes cannot be effectively integrated, and the performance requirements of low power consumption, long endurance, strong mobility, small size, and the functional requirements of quiet reconnaissance and rotary-wing protection cannot be met at the same time. The amphibious robot with performance or functional short board cannot effectively play a role in the complex building space. At the same time, the existing robot has little analysis on the dynamics characteristics, which is not conducive to the control of the motion state of the robot and is not convenient for playing an effective role in the complex building space. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide a crawling mode dynamics modeling method of an amphibious robot, to solve the problem that the existing robot cannot effectively play a role in the complex building space.

[0006] The present application provides a crawling mode dynamics modeling method of an amphibious robot, comprising the following steps:

[0007] Step 1: kinematic analysis of a single driving claw is performed, and a kinematic model of the driving claw is established;

[0008] Step 2: the overall motion of the crawling mode is analyzed, and a kinematic model of the amphibious robot is established.

[0009] Further, in the crawling mode motion of the amphibious robot, the driving wheels only rotate reversely around the Y axis of the two driving wheels.

[0010] Further, in the crawling mode, the three wheel claws are always in a stable expanded state and form the driving claws under the meshing action of the driving wheels.

[0011] Further, in the crawling mode, the driving claws include a centering rotation phase and a rolling rotation phase.

[0012] Further, when the driving claws are in the centering rotation phase, the body gravity direction of the amphibious robot intersects with the line between the ground contact point A1 of the driving claw and the ground contact point A2 of the guide wheel.

[0013] Further, when the body gravity direction of the amphibious robot passes through the ground contact point A1 of the driving claw, the driving claw is in a critical state of the two phases.

[0014] Further, in the rolling rotation phase, the horizontal velocity v C1x n and the vertical velocity v C1x n The calculation formula is:

[0015]

[0016]

[0017] In the formula, Δt is a discrete time interval, ω C1 * is the rotation speed of the driving wheel center when the driving claw is in the critical state of the two phases, R1 is the rotation radius of the driving claw in the rolling rotation phase, ΔE i is the kinetic energy variable at time i, J K is the rotation inertia of the driving claw about the rotation center K point.

[0018] Further, in the crawling mode, the horizontal velocity of the driving claw and the movement speed of the amphibious robot in the world coordinate system W are related as follows:

[0019]

[0020] In the formula, D1 is the distance between the two driving claw wheels, D2 is the distance between the guide rod and the farther driving claw wheel, θ Bz is the angle of the robot about the z axis of the world coordinate system, v Bx is the speed of the robot about the x axis of the world coordinate system W, v By is the speed of the robot about the y axis of the world coordinate system W, and ωBz is the rotation speed of the robot around the z-axis of the world coordinate system W.

[0021] Further, the nonlinear equation between the driving claw angular acceleration and the driving torque is:

[0022] In the formula, M2=diag{m,m,JZ2}, wherein m is the mass of the amphibious robot, J Z2 is the moment of inertia matrix of the amphibious robot along the Z B axis.

[0023] Further, S2 is the Jacobian matrix between the motion speed and the driving wheel angular speed, and is specifically:

[0024]

[0025] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0026] (1) The crawling mode dynamics modeling method of the amphibious robot of the present application, the crawling and rolling assembly and the flight assembly are connected through the folding and unfolding assembly, are light in weight and small in size, the amphibious robot is suitable for single person to carry, has three motion modes of rolling, crawling and flying, and two space deployable mechanisms of wheel-leg switching and arm folding and unfolding, so that the amphibious robot realizes the switching between rolling and crawling and the switching between rolling and flying, and can adapt to all-around operation and use in complex spaces such as buildings and underground.

[0027] (2) The crawling mode dynamics modeling method of the amphibious robot of the present application, when the amphibious robot is switched to the rolling or crawling state, the core devices such as the motor and the propeller in the flight state are protected, and the system reliability is higher.

[0028] (3) The crawling mode dynamics modeling method of the amphibious robot of the present application, the amphibious robot can pass through a space with a minimum height of 250mm and a minimum width of 350mm, and the crawling process can cross over obstacles such as stairs and doorsteps with a height of 150mm, is suitable for deepening into different areas of urban building spaces for high mobility, long endurance and low noise to perform reconnaissance and strike tasks, and can greatly improve the operation efficiency of traditional unmanned aerial vehicles or unmanned vehicles, and provides technical support for all-around reconnaissance and strike actions in complex spaces.

[0029] (4) The crawling mode dynamics modeling method of the amphibious robot of the present application, in order to meet the demand of all-around all-terrain operation in complex building spaces, combines the characteristics of two types of unmanned platforms, fully utilizes the advantages of the two types of unmanned platforms, and avoids simple superposition of the structures and functions of the two types of unmanned platforms to the maximum extent, thereby providing a kind of idea for realizing target search, identification, tracking and attack tasks in all directions in complex urban building spaces.

[0030] (5) The crawling modal dynamics modeling method of the amphibious robot, through the dynamics modeling analysis on the crawling modal of the amphibious robot, the mechanical characteristics and operation process of the amphibious robot in the crawling modal are clarified, and a basis for better motion control of the amphibious robot is provided.

[0031] The above technical solutions in the present application can also be combined with each other to realize more preferred combination solutions. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the present application. The purposes and other advantages of the present application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated herein and constitute a part of the detailed description. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0033] Figure 1 The coordinate system diagram under the crawling motion modal of the amphibious robot;

[0034] Figure 2 The fixed-point rotation phase diagram under the crawling motion modal of the amphibious robot;

[0035] Figure 3 The critical state diagram of phase conversion under the crawling motion modal of the amphibious robot;

[0036] Figure 4 The gyro wheel rotation phase diagram under the crawling motion modal of the amphibious robot;

[0037] Figure 5 The dynamics model diagram under the crawling motion modal of the amphibious robot;

[0038] Figure 6 The rolling modal structure diagram of the amphibious robot;

[0039] Figure 7 The crawling modal structure diagram of the amphibious robot;

[0040] Figure 8 The flying modal structure diagram of the amphibious robot.

[0041] Reference signs:

[0042] 1 - climbing roll assembly; 11 - first wheel leg group; 111 - first wheel claw; 1111 - first arc surface; 1112 - second arc surface; 1113 - third arc surface; 1114 - first gear; 1115 - first meshing part; 1116 - first climbing roll part; 112 - first wheel support; 1121 - first disc part; 1122 - first connecting rod; 113 - first drive wheel; 114 - first motor; 12 - second wheel leg group; 121 - second wheel claw; 1211 - fourth arc surface; 1212 - fifth arc surface; 1213 - sixth arc surface; 1214 - second gear; 1215 - second meshing part; 1216 - second climbing roll part; 122 - second wheel support; 1221 - second disc part; 1222 - second connecting rod; 123 - second drive wheel; 124 - second motor; 2 - flight assembly; 21 - arm; 211 - folding and unfolding rod; 2111 - second connecting rod; 2112 - middle rod; 2113 - third connecting rod; 212 - first connecting rod; 213 - propeller; 214 - third motor; 215 - limiting block; 216 - magnetic attraction piece; 3 - folding and unfolding assembly; 31 - first connecting plate; 32 - second connecting plate; 33 - fixed plate; 34 - moving plate; 35 - guide column; 351 - limiting boss; 36 - fixed column; 37 - linear servo; 4 - shooting assembly; 41 - depth camera; 42 - servo; 43 - first mounting rod; 44 - second mounting rod; 45 - third connecting rod; 5 - guide assembly; 51 - guide wheel; 52 - guide rod. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which constitute a part of this application, and illustrate the principles of the application together with the embodiments thereof, but are not intended to limit the scope of the application.

[0044] Most of the existing amphibious unmanned platforms simply stack the unmanned aerial vehicle and the unmanned vehicle, and directly install four wheels or a track on the bottom of the unmanned aerial vehicle. When a single index is measured, for example, the cruising time is increased, and the noise during the driving process is reduced, and there is a certain improvement. However, the two motion modes are not well integrated, resulting in an overall size that is too large or important flight components are not protected during driving. For example, when flying, the four wheels or the track component accounts for too large a proportion of the total weight, reduces the load capacity and the flight time, and the system has too many redundant parts, resulting in a platform size and weight that is still relatively large; during driving, the presence of the propeller and the arm reduces the vehicle passing capacity, and the propeller is easily hit by surrounding obstacles, affecting driving or causing damage to itself.

[0045] Embodiment 1

[0046] In one embodiment of the present application, as shown in the drawings, Figures 1-8As shown, a method for modeling the dynamics of the crawling mode of an amphibious robot is disclosed. The amphibious robot can generate three motion modes of rolling, crawling and flying through configuration changes. Different motion modes have different kinematic and dynamic characteristics. A reasonable dynamic model needs to be established according to the characteristics of different motion modes in order to perform motion planning, energy consumption calculation and safety analysis, so as to optimize the control method of the robot and improve the control accuracy. The dynamics of the crawling mode of the robot with a single guide component is analyzed below, and a dynamic model is constructed to provide a basis for algorithm design and motion control of the amphibious robot in the crawling mode.

[0047] As shown in Figure 1 , Figures 6-8 , in the crawling mode of the robot, the drive wheels (first drive wheel 113 and second drive wheel 123) only rotate reversely around the Y axis (Y C1 and Y C2 ) of the two drive wheels, and the gears of the three claws (first claw 111 and second claw 121) are always in a stable expanded state under the meshing action of the drive wheels, and form a driving claw. The effective radius of the claw (i.e. the distance from the drive wheel axis to the end of the claw) is R3, the distance between the drive wheel axis and the center line of the guide wheel is L1, and the radius of the guide wheel is R2. The three expanded claws form a driving claw in the spoke configuration, and differential steering is adopted when steering.

[0048] Step 1: kinematic analysis of a single driving claw, and a kinematic model of the driving claw is established using the coordinate system as shown in Figure 2 . In the crawling mode, the driving claw has two motion phases of centering rotation and rolling rotation. When the driving claw of the robot body gravity direction G intersects with the line between the ground contact point A1 of the driving claw and the ground contact point A2 of the guide wheel, the center of the driving wheel of the driving claw rotates around the A1 point, and is in the centering rotation phase, as shown in Figure 2 .

[0049] At this time, the rotational speed of the driving claw ω C1 , the included angle between L1 and R3 (which is calculated by the body IMU (Inertial Measurement Unit) and the drive wheel photoelectric encoder) is a known quantity, and when crossing an obstacle with a height of H1, its horizontal speed v C1x and vertical speed v C1z in the world coordinate system W can be calculated as follows:

[0050]

[0051]

[0052]

[0053] like Figure 3 As shown, when the robot's gravity direction G passes through the ground contact point A1 of the driving claw, the driving claw is in a critical state between two motion phases. At this time, the angle between R2 and the horizontal direction is... The angle between L1 and R2 is zero. The rotational speed of the center of the drive wheel is ω C1 * Then the vertical velocity v Bz The horizontal velocity v is zero. C1x * =-R3ω C1 * Next, the drive pawl will enter the wheel motion phase, and the horizontal velocity of the center point K of the wheel motion is v. Kx * =-R1ω C1 * .

[0054] like Figure 4 As shown, during the rotating phase of the wheel, the driving pawl will move with an angular velocity of ω around point K as the center and R1 as the radius. K The speed is v Kz The rotating wheel motion, the contact point between the driving pawl and the ground is A* on the outer edge of the pawl, the guide wheel no longer maintains contact with the ground, v C1x and v C1z Mainly determined by the initial velocity v at the critical state K point Kz * This is determined by the kinetic energy increment ΔE caused by the lowering of the center of gravity. The driving pawl is in an underactuated state, and the driving pawl moves at an angular velocity ω. C1 The constant low-speed rotation is mainly used to prevent the guide rod from colliding with obstacles.

[0055] Discretize the time intervals by Δt. Assuming the driving pawl rotates at a constant speed within the same time interval, the horizontal velocity v at time n is... C1x n and vertical velocity v C1z n It can be calculated using the following formula:

[0056]

[0057]

[0058] In the formula ΔE i Let J be the kinetic energy variable at time i. K Let K be the moment of inertia of the driving claw about the rotation center K.

[0059] Step 2: Analyze the overall motion of the crawling mode. Similar to the rolling mode, the crawling mode also employs differential steering, establishing a system as follows: Figure 5 The dynamic model shown.

[0060] The crawling motion is mainly driven by the horizontal velocity v of the driving claw. C1x and v C2x The relationship between the robot's velocity in the world coordinate system W and the horizontal velocity of the driving claw is as follows:

[0061]

[0062] In the formula, D1 is the distance between the two driving pawls (the circular wheels formed when the pawls retract), D2 is the distance from the guide rod to the more distant driving pawl, and θ Bz Let v be the angle between the robot and the z-axis of the world coordinate system. Bx Let v be the robot's velocity along the x-axis of the world coordinate system W. By Let ω be the y-axis velocity of the robot around the world coordinate system W. Bz Let be the rotational speed of the robot around the z-axis of the world coordinate system W.

[0063] The robot's inertia matrix in crawling mode is M2 = diag{m, m, J Z2}, where m is the robot mass, J Z2 For the robot along Z B The moment of inertia of the shaft. The nonlinear equation between the angular acceleration of the driving claw and the driving torque can then be expressed as follows:

[0064]

[0065] In the formula, matrix S2 is the Jacobian matrix between the motion velocity and the angular velocity of the driving wheel, which can be expressed by the following formula:

[0066]

[0067] Example 2

[0068] Another specific embodiment of the present invention, such as Figures 6-8 As shown, an amphibious robot (hereinafter referred to as the robot) is disclosed, including a crawling and rolling component 1 and a flight component 2 connected to each other. The crawling and rolling component 1 is used for the robot's crawling mode and rolling mode, and the flight component 2 is used for the robot's flight mode.

[0069] The climbing-rolling assembly 1 comprises a first wheel leg set 11 and a second wheel leg set 12, which are identical in structure. Specifically, the first wheel leg set 11 comprises three first pawls 111, two first wheel supports 112 and a first driving wheel 113. The three first pawls 111 are equicircular and mesh with the first driving wheel 113. The two first wheel supports 112 are symmetrically arranged on both sides of the first driving wheel 113 and are rotationally connected with the first driving wheel 113. The meshing end of the first pawl 111 with the first driving wheel 113 is rotationally connected with the first wheel support 112.

[0070] The first pawl 111 has a half-moon structure, comprising a first arc surface 1111, a second arc surface 1112 and a third arc surface 1113. The first arc surface 1111 is the surface in contact with the ground when the robot rolls. The three first arc surfaces 1111 are connected end to end to form a circle. At this time, the second arc surface 1112 is in close contact with the third arc surface 1113 of another first pawl 111, i.e., when the three first pawls 111 are fully retracted to form a circular wheel, the circular wheel is used to roll along the ground.

[0071] In this embodiment, when the three first pawls 111 are retracted to form a circular wheel, the second arc surface 1112 is in close contact with the third arc surface 1113 of another second pawl 111, i.e., when the three first pawls 111 are fully retracted to form a circular wheel, the circular wheel is used to roll along the ground.

[0072] The first arc surface 1111 and the second arc surface 1112 are one end of the first pawl 111. This end is the contact end with the ground when the robot is in the crawling mode. The other end of the first pawl 111 is provided with a first gear 1114 meshing with the first driving wheel 113. The first gear 1114 is located on the concave side of the first pawl 111 opposite the third arc surface 1113. The meshing end of the first pawl 111 with the first driving wheel 113 is provided with a through hole for connecting with the first wheel support 112.

[0073] In other words, the first pawl 111 has a half-moon structure, comprising a first meshing part 1115 and a first climbing-rolling part 1116. The first meshing part 1115 is provided with a through hole rotationally connected with the first wheel support 112, a first gear 1114 and a third arc surface 1113. The first climbing-rolling part 1116 comprises a first arc surface 1111 and a second arc surface 1112.

[0074] The first wheel support 112 comprises a first disc part 1121 and three first connecting rods 1122, which are evenly distributed on the edge of the first disc part 1121. The end of the first connecting rod 1122 is provided with a through hole for rotationally connecting with the first paw 111. The middle of the first disc part 1121 is provided with a through hole for rotationally connecting with the first driving wheel 113. In order to reduce the weight of the first wheel support 112, the first connecting rod 1122 is provided with a weight-reducing groove.

[0075] The first wheel leg group 11 further comprises a first motor 114, the output end of which is connected with a rotating shaft, which is rotationally connected with the first wheel support 112 and is connected with the first driving wheel 113 through a key. Under the driving of the first motor 114, the first driving wheel 113 can rotate clockwise and counterclockwise. For the convenience of understanding, it is defined that when the three first paws 111 are in an unfolded state during the rotation of the first driving wheel 113, the first motor 114 rotates clockwise; and when the three first paws 111 are in a contracted circular state during the rotation of the first driving wheel 113, the first motor 114 rotates counterclockwise.

[0076] Understandably, the second wheel leg group 12 comprises second paws 121, a second wheel support 122 and a second driving wheel 123. The second paw 121 is provided with three, and the three second paws 121 are equally angularly connected with the second driving wheel 123. The second wheel support 122 is provided with two, and the two second wheel supports 122 are symmetrically arranged on the two sides of the second driving wheel 123 and are rotationally connected with the second driving wheel 123. The meshing end of the second paw 121 and the second driving wheel 123 is rotationally connected with the second wheel support 122.

[0077] The second paw 121 is in a half-moon shape structure, comprising a fourth arc surface 1211, a fifth arc surface 1212 and a sixth arc surface 1213. The fourth arc surface 1211 is used as the surface in contact with the ground when the robot rolls. The three fourth arc surfaces 1211 are connected end to end to form a circle. At this time, the fifth arc surface 1212 is in close contact with the sixth arc surface 1213 of the other second paw 121, that is, when the three second paws 121 are completely contracted to form a circular wheel, it is used for rolling along the ground.

[0078] In this embodiment, when the three second paws 121 are contracted into a circular wheel, the fifth arc surface 1212 is in close contact with the sixth arc surface 1213 of the other second paw 121, and there is no gap between them, which ensures the stability of the robot during rolling.

[0079] The second claw 121 is provided with a second gear 1214 at one end thereof, which is in mesh with the second driving wheel 123. The second gear 1214 is located on the inner concave side of the second claw 121 opposite to the sixth arc surface 1213. The meshing end of the second claw 121 and the second driving wheel 123 is provided with a through hole for connecting with the second wheel support 122.

[0080] In other words, the second claw 121 has a half-moon shape structure, including a second meshing part 1215 and a second climbing-rolling part 1216. The second meshing part 1215 is provided with a through hole for rotationally connecting with the second wheel support 122, and the second gear 1214 and the sixth arc surface 1213. The second climbing-rolling part 1216 includes the fourth arc surface 1211 and the fifth arc surface 1212.

[0081] The second wheel support 122 includes a second disc part 1221 and three second connecting rods 1222. The three second connecting rods 1222 are evenly distributed on the edge of the second disc part 1221. The end of the second connecting rod 1222 is provided with a through hole for rotationally connecting with the second claw 121. The middle of the second disc part 1221 is provided with a through hole for rotationally connecting with the second driving wheel 123. In order to reduce the weight of the second wheel support 122, the second connecting rod 1222 is provided with a weight-reducing groove.

[0082] The second wheel leg set 12 further includes a second motor 124. The output end of the second motor 124 is connected with a rotating shaft, which is rotationally connected with the second wheel support 122 and is connected with the second driving wheel 123 through a key. Under the driving of the second motor 124, the second driving wheel 123 can rotate clockwise and counterclockwise. In order to facilitate understanding, it is defined that when the three second claws 121 are in an unfolded state during the rotation of the second driving wheel 123, the second motor 124 rotates clockwise; and when the three second claws 121 are in a contracted round wheel state during the rotation of the second driving wheel 123, the second motor 124 rotates counterclockwise.

[0083] In order to increase the friction force between the wheels and the ground in the robot rolling mode, grooves are uniformly arranged on the first arc surface 1111 and the fourth arc surface 1211.

[0084] In the embodiment, the robot travels by wheels in the rolling mode and travels by leg claws in the crawling mode. When the wheel-leg is switched, the driving wheels (the first driving wheel 113 and the second driving wheel 123) are engaged with the wheel claws (the first wheel claw 111 and the second wheel claw 121), and when the motor (the first motor 114 and the second motor 124) operates counterclockwise, the three wheel claws rotate clockwise to the adhering position to form a circular wheel shape, and the driving wheels continue to rotate to drive the circular wheel to rotate counterclockwise. When the driving wheels operate clockwise, the three wheel claws rotate counterclockwise to expand, and reach the dead point position to form a support leg state, and the driving wheels continue to rotate to drive the expanded wheel claws to rotate clockwise.

[0085] In the building environment, typical obstacles include staircases, door frame bottom edges, etc., and the height of the staircase is higher, generally about 150 mm, so the height capability of the robot in the building environment needs to reach 150 mm. The wheel claws are expanded by the motor driving the driving wheels to rotate in the reverse direction, and the robot is switched to the support leg crawling state, which can greatly improve the obstacle crossing capability. For example, when the outer diameter of the circular wheel formed by the wheel claws is 160 mm and the center wheel (driving wheel) is directly 40 mm, when the robot is expanded to the support leg crawling state, the distance between the contact ends of the two adjacent wheel claws is 279 mm, which can cross the 150 mm high staircase.

[0086] The flight assembly 2 includes four groups of structurally identical arms 21, and the four groups of arms 21 are arranged between the first wheel-leg group 11 and the second wheel-leg group 12 and are located on four parallel edges of the space cuboid.

[0087] Specifically, the arm 21 includes a folding rod 211, a first connecting rod 212, a propeller 213, and a third motor 214. The first connecting rod 212 is hinged to the folding rod 211, and the third motor 214 is arranged at the middle part of the folding rod 211 and drives the propeller 213 to rotate. That is, one end of the third motor 214 is connected to the middle part of the folding rod 211, and the other end is connected to the propeller 213. When the arm 21 is in the non-expanded state, the propeller 213 faces the internal space of the robot.

[0088] The folding rod 211 is a curved rod and includes a second connecting rod 2111, an intermediate rod 2112, and a third connecting rod 2113 connected in sequence. In order to leave space for the propeller 213, the intermediate rod 2112 protrudes away from the internal space of the robot relative to the second connecting rod 2111 and the third connecting rod 2113. The second connecting rod 2111 and the third connecting rod 2113 are in the same plane. The propeller 213 is arranged in the space reserved by the intermediate rod 2112. One end of the first connecting rod 212 is hinged to the connection between the second connecting rod 2111 and the intermediate rod 2112, and the length of the first connecting rod 212 is greater than the length of the second connecting rod 2111. When the arm 21 is expanded, the third connecting rod 2113 is in a cantilevered state.

[0089] In order to avoid the interference of the robot when the robot is in the climbing mode and the rolling mode, the non-hinged end of the folding and unfolding rod 211 is provided with a magnetic suction member 216 for absorbing the first connecting plate 31 described below, and the magnetic suction member 216 is preferably a magnet. When the robot arm 21 is folded, the cantilever end (non-hinged end) of the folding and unfolding rod 211 is absorbed on the first connecting plate 31 by the magnetic suction member 216, further ensuring the stability of the robot arm 21 in the folded state.

[0090] Understandably, in order to reduce the weight of the flight assembly 2, the folding and unfolding rod 211 is provided with a weight-reducing groove.

[0091] In order to limit the rotation of the propeller blades during the folding process, the robot arm 21 further comprises a limiting block 215 provided on the first connecting rod 212, and the propeller blades stop rotating when they touch the limiting block 215 during the folding process of the robot arm 21.

[0092] In order to place the climbing and rolling assembly 1 and the flight assembly 2 and fold and unfold the robot arm 21, the robot further comprises a folding and unfolding assembly 3 located between the first wheel leg group 11 and the second wheel leg group 12 and used for connecting the first wheel leg group 11, the second wheel leg group 12 and the flight assembly 2, so that the core devices such as motors and propellers of the flight mode are protected when the robot is switched to the rolling mode or the climbing mode, and the system reliability is higher.

[0093] The folding and unfolding assembly 3 comprises first connecting plates 31, second connecting plates 32, fixed plates 33 and moving plates 34 which are parallel to each other, and the first connecting plates 31, the fixed plates 33, the moving plates 34 and the second connecting plates 32 are sequentially arranged from the first wheel leg group 11 to the second wheel leg group 12. The first connecting plates 31 and the second connecting plates 32 are the same in structure. The first motor 114 is installed on the first connecting plate 31, and the second motor 124 is installed on the second connecting plate 32. When the robot arm 21 is in the folded state, one end (hinged end) of the folding and unfolding rod 211 is hinged to the side surface of the moving plate 34, and the other end is absorbed to the side surface of the fixed plate 33; when the robot arm 21 is in the unfolded state, the hinged relationship of the hinged end of the folding and unfolding rod 211 is unchanged, and the other end is a cantilever end. In order to avoid the interference of the fixed plate 33 with the propeller 213 in the folded state of the robot arm 21, the side surface of the fixed plate 33 is provided with a groove.

[0094] Further, in order to reduce the weight of the robot, the fixed plate 33 is provided with a weight-reducing groove, and the middle of the moving plate 34 is hollow, only the edge part is reserved.

[0095] One end of the first connecting rod 212 is hinged to the retracting rod 211, and the other end is hinged to the surface of the fixed plate 33 near the moving plate 34. To avoid the first connecting rod 212 interfering with the propeller 213, the first connecting rod 212 is hinged to the side of the retracting rod 211. When the four first connecting rods 212 are hinged to the fixed plate 33, the four hinge points are located adjacent to each other on the diagonal of the fixed plate 33.

[0096] The retractable assembly 3 also includes guide posts 35 and fixed posts 36. There are four guide posts 35 and four fixed posts 36. One end of the fixed post 36 is connected to the first connecting plate 31 and the other end is connected to the fixed plate 33. The fixed posts 36 are located at the four corners of the fixed plate 33. One end of the guide post 35 is connected to the fixed plate 33 and the other end passes through the moving plate 34 and is connected to the second connecting plate 32. The guide posts 35 and the fixed posts 36 are collinear.

[0097] In order to achieve the extension and retraction of the arm 21, the extension and retraction assembly 3 also includes a linear servo motor 37. One end of the linear servo motor 37 is connected to the fixed plate 33, and the other end is connected to the movable plate 34. Driven by the linear servo motor 37, the movable plate 34 moves along the guide post 35 to achieve the extension and retraction of the arm 21.

[0098] To limit the excessive extension of the robotic arm 21, a limiting boss 351 is provided on the guide post 35. When the moving plate 34 moves to the limiting boss 351 under the drive of the linear servo motor 37, the robotic arm 21 is fully extended and can be used for the robot's flight mode.

[0099] In this embodiment, the four arms 21 are retracted and extended using a slider-link mechanism similar to the folding and unfolding of an umbrella. A linear servo motor 37, fixed to the upper part of the fixed plate 33, drives the lower moving plate 34 to move up and down in the guide post 35. The moving plate 34 is connected to the second link 2111 via a rotating shaft. The two ends of the first link 212 are connected to the fixed plate 33 and the retraction / extension rod 211 respectively via rotating shafts. When the moving plate 34 moves toward the second connecting plate 32, the arms 21 rotate toward the first connecting plate 31 to retract; conversely, the arms 21 unfold.

[0100] In this embodiment, the crawling and rolling component 1 and the flying component 2 are connected by the retraction component 3, avoiding the simple superposition of the two. The three are connected in a compact manner, making the robot lightweight and small in size, suitable for single-person carrying. It also has three motion modes: rolling, crawling and flying. The wheel-leg switching and arm retraction and extension mechanisms enable it to switch between rolling and crawling, and between rolling and flying, and can be used in all directions in complex spaces such as buildings and underground.

[0101] In order that the robot observes the surrounding environment during driving, the robot further comprises a shooting assembly 4, the shooting assembly 4 comprising a depth camera 41, a steering engine 42, a first mounting rod 43, a second mounting rod 44 and a third connecting rod 45, the depth camera 41 being connected with an output shaft of the steering engine 42, and being capable of realizing change of a shooting direction under driving of the steering engine 42, one end of the first mounting rod 43 being fixedly connected with the fixed plate 33, the other end being rotatably connected with one end of the third connecting rod 45, the other end of the third connecting rod 45 being rotatably connected with the second mounting rod 44, the other end of the second mounting rod 44 being fixedly connected with the moving plate 34, the steering engine 42 being arranged at the hinged end of the second mounting rod 44 and the third connecting rod 45, and the third connecting rod 45 being hinged with the first mounting rod 43 and the second mounting rod 44 respectively, so that mechanism interference of the arm 21 during folding and unfolding is avoided.

[0102] In order that the robot drives stably in the rolling mode and the crawling mode, the robot further comprises a guiding assembly 5, the guiding assembly 5 comprising guiding wheels 51 and guiding rods 52, the guiding wheels 51 being arranged at one end of the guiding rods 52 and being used for rolling on the ground. The guiding assembly 5 is provided with one or two, when the guiding assembly 5 is provided with one, the other end of the guiding rod 52 being fixedly connected with the fixed plate 33; when the guiding assembly 5 is provided with two, the other ends of the two guiding rods 52 are respectively fixedly connected with the first connecting plate 31 and the second connecting plate 32.

[0103] The above merely describes a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method of modeling the dynamics of a crawling mode of an amphibious robot, the method comprising the steps of: Comprise: ​ Step 1: kinematic analysis is carried out on single driving claw, and the kinematic model of driving claw is established; In the step 1, the amphibious robot is in the crawling mode motion, the driving claw includes the centering rotation motion phase and the rolling rotation motion phase; When the gravity direction of the amphibious robot intersects with the line between the ground contact point A1 of the driving claw and the ground contact point A2 of the guide wheel, the driving claw is in the centering rotation motion phase; when the gravity direction of the amphibious robot passes through the ground contact point A1 of the driving claw, the driving claw is in the critical state of the two motion phases; During the centering rotation phase, the horizontal velocity of the driving pawl in the world coordinate system W and vertical velocity The calculation formula is: ， ， ， where L1 is the distance between the drive wheel axis and the center line of the guide wheel, R2 is the radius of the guide wheel, R3 is the distance from the drive wheel axis to the end of the claw, H1 is the height of crossing the obstacle, is the rotational speed of the drive claw, φ is the angle between L1 and R3, and φ1 is the angle between R2 and the horizontal direction. The horizontal velocity of the driving claw at time n under the cycloid rotation motion phase and the vertical velocity The calculation formula is: ， ， where Δt is a discretization time interval, R1 is the radius of rotation of the driving pawl in the rotation phase of the driving wheel, ΔE i is the kinetic energy variable at time i, J K is the moment of inertia of the driving pawl about the point of rotation K. Step 2: the whole motion of the crawling mode is analyzed, and the kinematic model of the amphibious robot is established.

2. The method of claim 1, wherein, In the crawling mode motion of the amphibious robot, the driving wheel only rotates reversely around the Y axis of the two driving wheels.

3. The method of claim 2, wherein, In the crawling mode motion of the amphibious robot, the gear of the three wheel claws is always in the stable expansion state under the meshing action of the driving wheel, and the driving claw is formed.

4. The method of crawl mode dynamic modeling of an amphibious robot according to any one of claims 1-3, characterized in that, In the step 2, the relationship between the motion speed of the amphibious robot in the world coordinate system W and the horizontal speed of the driving claw is as follows: ， where D1 is the distance between the two driving pawl wheels, D2 is the distance between the guide rod and the farther driving pawl wheel, is the angle of the robot around the z-axis of the world coordinate system, is the velocity of the robot around the x-axis of the world coordinate system W, is the velocity of the robot around the y-axis of the world coordinate system W, is the angular velocity of the robot around the z-axis of the world coordinate system W.

5. The method of claim 4, wherein, The nonlinear equation between the angular acceleration of the driving claw and the driving torque is as follows: ， wherein where m is the mass of the amphibious robot, J Z2 is the moment of inertia matrix of the amphibious robot along the Z B axis.

6. The method of claim 5, wherein, S2 is the Jacobian matrix between the motion speed and the angular velocity of the driving wheel, and specifically is as follows: 。

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