A polymorphic quadruped robot and control method thereof

Abstract

The present invention relates to a polymorphic quadruped robot and its movement mode. The robot includes a walking and posture changing mechanism, a steering mechanism, and a fuselage shell, which include a normal walking posture, a swinging walking posture, a semi-lying posture, a steering posture, and a shell-shrinking posture. The walking and posture changing mechanism is connected to the steering mechanism, and the posture is changed by the walking and posture changing mechanism, and the steering and shell-shrinking functions are realized in combination with the steering mechanism. The present invention is suitable for intricate pipelines for pipeline inspection and maintenance; suitable for disaster areas where rocks fall, to realize the function of transporting materials; suitable for camouflaged shooting in the field with complex terrain, and for bulletproof transportation in the military; it has flexible turning ability and unique walking posture, and can be used as an auxiliary detection and transportation tool for large construction machinery. The present invention has extraordinary significance for the modernization and intelligent construction of dangerous jobs.

Description

Technical Field

[0001] The present invention belongs to the technical field of mobile robots, and in particular relates to a polymorphic quadruped robot and a control method thereof. Background Art

[0002] For more than a century, mobile robots have been a hot topic in the research field. They have great development potential and research value both now and in the near future. Mobile robots are mainly divided into three categories: wheeled, tracked and legged. At present, the most common mobile robots are wheeled and tracked. The technologies related to these two types of mobile robots are also relatively mature. Wheeled and tracked mobile robots have good motion performance on flat roads. However, the movement of wheeled and tracked mobile robots on rugged roads still has great limitations. The mechanical structure design of quadruped robots is mostly based on bionics, simulating the efficient movement cycle process of animals, hoping to achieve the ability to coordinate periodic movement, and thus design bionic machinery that can adapt to unfamiliar and challenging environments. Developed countries are at the forefront of the world in the research of legged robots, among which the United States, Japan, Canada and other developed countries are in the leading stage. Denmark, Switzerland, Japan and South Korea also have a series of legged robot development products. Some domestic universities and companies have also developed various legged robots one after another, such as the Chinese Academy of Sciences, Xi'an Jiaotong University, Shanghai Jiaotong University, Tsinghua University and Beijing Institute of Technology have also developed various legged robots one after another. However, the problem that still exists with foot-type robots today is that in order to walk flexibly and easily cross obstacles, each mechanical foot must have enough degrees of freedom to achieve efficient and flexible movements. The higher the overall requirements for the robot, the more difficult it is to design. The degrees of freedom of a single leg of a foot-type robot are generally 3 to 6, which is already quite complicated, and the total degrees of freedom of the entire robot can reach 10 to 18. This requires very high precision control of the control system, which is complex, difficult and costly to calculate. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a polymorphic quadruped robot of a new configuration and a control method thereof, which has the function of variable posture and morphology, is a mechanical equipment suitable for a variety of working occasions and has a high carrying capacity.

[0004] A multi-modal quadruped robot, comprising a walking and posture changing mechanism, a steering mechanism and a body shell, wherein the walking and posture changing mechanism is rotatably connected around the steering mechanism, and a body shell is arranged on the top of the steering structure; the robot comprises a normal walking posture, a swinging walking posture, a semi-prone posture, a steering posture and a shell-shrinking posture;

[0005] The walking and posture-changing mechanism includes four legs, which are symmetrically connected to the left and right sides of the steering mechanism and are symmetrical relative to the front and rear sides of the steering mechanism. Each leg of the walking and posture-changing mechanism includes a motor, a calf, a cylindrical push rod, a crank, a connecting rod, a leg bracket, a rocker, a hollow rod and an electric push rod. The leg bracket is connected to the steering mechanism, the motor is fixed to the leg bracket, one end of the crank is connected to the output end of the motor, and the other end of the crank is rotatably connected to the connecting rod; the fixed end of the electric push rod is rotatably connected to the leg bracket, and the telescopic end of the electric push rod is rotatably connected to the front end of the calf; the two ends of the rocker are respectively rotatably connected to the fixed ends of the connecting rod and the electric push rod; the two ends of the hollow rod are respectively connected to the rod body of the connecting rod and the electric push rod; one end of the cylindrical push rod is rotatably connected to the inside of the cavity of the hollow rod, and the other end is rotatably connected to the calf near the front end of the calf;

[0006] The steering mechanism comprises a fuselage bottom plate, an intermediate plate, four biaxial servos, four servo upper shells, and four servo lower shells. The servo upper shells and the servo lower shells are respectively mounted on the upper and lower sides of the intermediate plate by bolts in a centrally symmetrical manner, and the bottom of the servo lower shell is fixed to the fuselage bottom plate; the biaxial servo is fixed to the intermediate plate, and the two ends of the biaxial servo are respectively fixed to the servo upper shell and the servo lower shell; the leg bracket of the legs in the walking and posture changing mechanism is connected to the biaxial servo; a groove is provided between each two adjacent biaxial servos on the intermediate plate;

[0007] The upper shell of the fuselage is connected to the upper part of the upper shell of the steering gear in the steering mechanism by bolts, and the outer diameter of the upper shell of the fuselage is larger than the outer diameter of the steering mechanism; the upper shell of the fuselage, the middle plate and the bottom plate of the fuselage constitute the body of the robot.

[0008] The end of the calf is the foot end, which is cylindrical, and the center line of the cylinder is parallel to the ground.

[0009] The foot end is covered with rubber on the outside.

[0010] The motor is a DC motor.

[0011] Side plates are arranged on the sides of the groove.

[0012] The two shaft ends of the dual-axis steering gear are respectively connected to the two ends of the leg bracket.

[0013] The upper shell is in a dome shape.

[0014] The cross sections of the steering gear upper shell and the steering gear lower shell are L-shaped, and the dual-axis steering gear is placed in a cavity formed by the steering gear upper shell, the middle plate and the steering gear lower shell.

[0015] The shank, cylindrical push rod, crank, connecting rod, rocker, hollow rod and electric push rod in each leg are of different lengths; the electric push rod is a pen-type electric push rod, and the motor is arranged inside the electric push rod.

[0016] The control method for realizing five postures by using the above-mentioned multi-modal quadruped robot is characterized by the following:

[0017] The first type: normal walking posture: including walk gait and trot gait, in which trot gait: during walking, the four legs are divided into two groups, the two legs located on the diagonal are one group, and the walking pace of the two legs in the same group is consistent; the two groups of legs have a phase difference through the control of the motor adjustment, and during the movement, there is always a group of legs, that is, the two legs located in the same diagonal direction, in contact with the ground; walk gait: during walking, first lift the leg in the left front or right front direction relative to the walking direction, and lift the leg in the right rear or left rear direction relative to the walking direction at the same time as the first leg touches the ground, and lift the right front or left front leg at the same time as the second leg touches the ground, and finally lift the left rear or right rear leg. During the whole process, ensure that the upper leg touches the ground before the next leg can be lifted, that is, the two legs in the diagonal direction are lifted and lowered in the order of front and back relative to the walking direction, and three legs are always kept in contact with the ground during the walking process;

[0018] The upper shell of the fuselage is provided with an access opening, and items can be placed inside the upper shell of the fuselage, thereby carrying objects;

[0019] The second type: swing walking posture: In this state, the forward direction is perpendicular to the motion plane of the crank-connecting rod rocker mechanism of the leg. When the right front leg or the left front leg is lifted relative to the forward direction, it is driven by the dual-axis servo to rotate 20° to 30° counterclockwise or clockwise. When the leg falls, the left rear leg or the right rear leg begins to lift and is driven by the dual-axis servo to rotate 20° to 30° in the forward direction. The action sequence of the four legs is the same as the walking gait, and the rotation angle is the same.

[0020] When walking in water, the four legs simultaneously perform the above-mentioned swinging walking posture, that is, the four legs are lifted and turned at the same time;

[0021] The third type: Steering posture: driven by the dual-axis steering gear, the four legs complete the required rotation angles in turn according to the actual steering conditions;

[0022] The fourth type: half-volt posture: the four electric push rods extend at the same time to lower the body. This state can achieve normal walking posture, swinging walking posture and turning posture.

[0023] Fifth: Shell-shrinking posture: The electric push rod is extended to its maximum length, the height of the robot is lowered, the center of gravity is lowered, and the dual-axis servo drives the legs to rotate into the groove of the middle plate. The four legs are retracted into the shell in turn, and the legs are hidden.

[0024] The beneficial effects of the present invention are as follows: the present invention has a wide range of applications: it is applicable to intricate pipelines for pipeline inspection and repair; it is applicable to disaster areas where rocks have fallen to realize the function of transporting materials; it is applicable to camouflage shooting in the field with complex terrain, and is used for bulletproof transportation in the military; it has flexible turning ability and unique walking posture, and can be used as an auxiliary detection and transportation tool for large-scale construction machinery. The present invention has extraordinary significance for the modernization and intelligent construction of dangerous types of work. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 is a cross-sectional view of the present invention;

[0027] Figure 3 It is a schematic diagram of the walking and posture changing mechanism of the present invention when the foot end of the leg contacts the ground;

[0028] Figure 4 It is a schematic diagram of the leg posture in the shell-shrinking state of the present invention;

[0029] Figure 5 A top view of the legs in the walking and posture changing mechanism of the present invention;

[0030] Figure 6 for Figure 5 AA view;

[0031] Figure 7 This is a schematic diagram of the normal walking state of the present invention;

[0032] Figure 8 for Figure 7 A top view of

[0033] Fig. 9 It is a schematic diagram of the shell shrinking state of the present invention;

[0034] Fig.10 for Fig. 9 A top view of

[0035] Fig.11 It is a front view of the present invention in a semi-volt state;

[0036] in,

[0037] 1- walking and posture changing mechanism, 2- steering mechanism, 3- body, 4- calf, 5- cylindrical push rod, 6- crank, 7- connecting rod, 8- leg bracket, 9- rocker, 10- hollow rod, 11- electric push rod, 12- motor, 13- body bottom plate, 14- middle plate, 15- body upper shell, 16- servo lower shell, 17- servo upper shell, 18- side plate. DETAILED DESCRIPTION

[0038] In order to better explain the present invention and facilitate understanding, the technical solutions and effects of the present invention are described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0039] like Figure 1-2 A polymorphic quadruped robot comprises a walking and posture changing mechanism 1, a steering mechanism 2 and a body shell 15, wherein the walking and posture changing mechanism 1 is rotatably connected around the steering mechanism 2, a body shell 15 is arranged on the top of the steering structure, and the body shell 15 and the steering mechanism 2 realize the shell shrinking function, and the polymorphic quadruped robot has walking function, steering function and shell shrinking function, including normal walking posture, swinging walking posture, half-lying posture, steering posture and shell shrinking posture.

[0040] The walking and posture changing mechanism 1 includes four legs, which are symmetrically connected to the left and right sides of the steering mechanism 2, and are symmetrical with respect to the front and rear sides of the steering mechanism 2. Each leg is provided with a prime mover driven by a motor 12, and the prime mover is driven to realize the walking of the whole machine. Each leg of the walking and posture changing mechanism 1 includes a motor 12, a shank 4, a cylindrical push rod 5, a crank 6, a connecting rod 7, a leg bracket 8, a rocker 9, a hollow rod 10 and an electric push rod 11. The shank 4, the cylindrical push rod 5, the crank 6, the connecting rod 7, the rocker 9, the hollow rod 10 and the electric push rod 11 in each leg are of different lengths, and are important mechanisms for realizing the walking of the robot. The cylindrical push rod 5, the crank 6, the connecting rod 7, the leg bracket 8, the rocker 9, the hollow rod 10 and the electric push rod 11 are seven connecting rods of different sizes, which are the main components of the walking and posture changing mechanism 1, and realize the walking of the whole machine when the robot is working. The leg bracket 8 is connected to the steering mechanism 2, the motor 12 is fixed to the leg bracket 8, one end of the crank 6 is connected to the output end of the motor 12, and serves as the prime mover of the walking and posture changing mechanism 1, and the other end of the crank 6 is rotatably connected to the connecting rod 7; the fixed end of the electric push rod 11 is rotatably connected to the leg bracket 8, and the telescopic end of the electric push rod 11 is rotatably connected to the front end of the calf 4; the two ends of the rocker 9 are rotatably connected to the fixed ends of the connecting rod 7 and the electric push rod 11 respectively; the two ends of the hollow rod 10 are respectively connected to the rod body of the connecting rod 7 and the electric push rod 11; one end of the cylindrical push rod 5 is rotatably connected to the inside of the cavity of the hollow rod 10, and the other end is rotatably connected to the position of the calf 4 near the front end of the calf 4. The crank 6, the connecting rod 7 and the rocker 9 constitute a crank rocker mechanism, and the hollow rod 10, the electric push rod 11, the calf 4, and the cylindrical push rod 5 constitute a parallelogram mechanism. When walking, the motor 12 rotates and drives the crank 6 to make a rotary motion. The crank 6 drives the rocker 9 to move through the connecting rod 7. The movement of the crank-rocker mechanism drives the parallelogram mechanism connected thereto to move, that is, the crank 6 moves through the connecting rod 7 while driving the hollow rod 10 to move. Since the hollow rod 10, the electric push rod 11, the calf 4, and the cylindrical push rod 5 form a parallelogram mechanism, the movement of the hollow rod 10 drives the movement of the cylindrical push rod 5, the electric push rod 11, and the calf 4. There are two ways to lift the legs: the first is to extend the electric push rod 11 to lift the legs, and the electric push rod 11 contracts to land the legs; the second is to drive the motor 12 to make a rotary motion. Both methods realize and amplify the movement of the foot end, thereby realizing the walking of the robot. Figure 3-6 shown.

[0041] The electric push rod 11 is a pen-type electric push rod, and the motor is arranged inside the electric push rod.

[0042] The end of the calf 4 is the foot end, which is cylindrical, and the center line of the cylinder is parallel to the ground. The cylindrical foot end has a relatively simple structure, and the foot end uses line contact, which has stronger adaptability than the wheel type, has stronger contact with the ground, and has good adaptability to complex terrain environments; and there is no need to design a rotating device at the connection with the leg body of the calf 4. The foot end is covered with rubber on the outside, which can buffer when the foot end collides with the ground, reducing the impact of the foot end on its upper body, which lays a good foundation for the whole machine walking of the robot and can ensure the stability of the robot when working.

[0043] The motor 12 is a DC motor 12 .

[0044] The walking and posture changing mechanism 1 includes two walking gaits, namely walk gait and trot gait, and the distance between each two adjacent legs is the same. The motor 12 rotates, and under the drive of the motor 12, the four legs in the walking and posture changing mechanism 1 cooperate with each other according to work needs, and the motors 12 in each leg are independent of each other and cooperate with each other. When it is necessary to move at a medium to high speed, the trot gait is adopted, and the medium to high speed is 0.5m / s~0.8m / s; when it is necessary to move at a low and stable speed, the walk gait is adopted, and the low speed is 0.1m / s~0.5m / s. Each leg is a closed-chain mechanism with a single degree of freedom, and one power source can determine the foot end trajectory.

[0045] Trot gait: During walking, the four legs are divided into two groups, two legs located on the diagonal line form one group, and the two legs in the same group walk in unison; the two groups of legs have a phase difference by controlling the motor 12 to adjust, thereby realizing the diagonal walking gait of bionic animals, which is the trot gait. When the robot walks in the trot gait, there is always a group of legs, that is, two legs located in the same diagonal direction, in contact with the ground during the movement.

[0046] Walk gait: imitate the walking gait of quadrupeds. In the process of walking, first lift the left or right front leg relative to the walking direction, then lift the right or left rear leg relative to the walking direction when the first leg touches the ground, then lift the right or left front leg when the second leg touches the ground, and finally lift the left or right rear leg. In the whole process, ensure that the previous leg touches the ground before the next leg can be lifted. That is, the two legs in the diagonal direction are lifted and lowered in the order of front and back relative to the walking direction, and three legs are always kept in contact with the ground during the walking process.

[0047] The walking and posture changing mechanism 1 has good bearing capacity: the single-degree-of-freedom closed-chain leg structure composed of seven different connecting rods can have a large bearing capacity. The robot's own gravity and the impact force generated during the movement will be dispersed to each rod to share the responsibility, so that the robot has good bearing capacity. When the robot is used to carry objects or add other equipment, the robot's good walking stability can be guaranteed. The motion control method of the walking and posture changing mechanism 1 is simple: the length of each connecting rod is determined by the scale design ant colony optimization method, so that the motion trajectory of the foot end of each leg is elliptical and unchanged when the leg mechanism moves forward, reducing the complex design algorithm, and adjusting the rotation speed of the four DC motors 12 and the phase difference between the four DC motors 12 to achieve the robot's travel speed adjustment and gait adjustment. For the trot gait, one rotation of the crank 6 is a walking cycle. In a walking cycle, the left front leg and the right hind leg are a group, and the right front leg and the left hind leg are a group. By controlling the rotation speeds of the two groups with different phases in a cycle, the first group of legs rises in half a cycle, and the other group of legs touches the ground, so that the two groups of legs alternately move, thereby completing the trot gait and walking smoothly. Similarly, for the walk gait, the four legs are each a group, and the cycle is divided into four equal parts. In each quarter cycle, one leg is lifted and the other three legs touch the ground to achieve the sequential movement of the walk gait.

[0048] like Figure 7-8 As shown, the steering mechanism 2 includes a fuselage bottom plate 13, an intermediate plate 14, four dual-axis servos, four servo upper shells 17, and four servo lower shells 16. The servo upper shells 17 and the servo lower shells 16 are respectively symmetrically mounted on the upper and lower sides of the intermediate plate 14 by bolts, that is, the servo upper shell 17 is symmetrically mounted on the upper side of the intermediate plate 14, and the servo lower shell 16 is symmetrically mounted on the lower side of the intermediate plate 14. The bottom of the servo lower shell 16 is fixed on the fuselage bottom plate 13, and the servo upper shell 17 and the servo lower shell 16 correspond to each other up and down; the servo upper shell 17 and the servo lower shell 16 connect the fuselage upper shell 15, the intermediate plate 14 and the fuselage bottom plate 13 together. The biaxial steering gear is fixed on the middle plate 14. The cross-section of the steering gear upper shell 17 and the steering gear lower shell 16 is L-shaped. The biaxial steering gear is placed in the cavity formed by the steering gear upper shell 17, the middle plate 14 and the steering gear lower shell 16. The steering gear upper shell 17 and the steering gear lower shell 16 can well protect the steering gear. The leg bracket 8 of the legs in the walking mechanism 1 is connected to the biaxial steering gear, and the biaxial steering gear connected to each leg is independent of each other. A groove is provided between each two adjacent biaxial steering gears on the middle plate 14 to provide space for the rotation of the legs. A side plate 18 is provided on the side of the groove.

[0049] The two shaft ends of the dual-axis steering gear are respectively connected to the two ends of the leg bracket 8, and the rotation of the shaft ends of the dual-axis steering gear drives the rotation of the legs, thereby changing the walking direction of the robot.

[0050] The quadruped robot does not work when it is moving straight; it imitates the hip joint when turning. When turning is required, the motor 12 rotates, driving a leg close to the forward direction to start lifting, wherein three legs are in contact with the ground and remain motionless. During the lifting process, the servo starts to rotate, driving the leg bracket 8 connected to the two shaft ends of the dual-axis servo to rotate, and the leg bracket 8 rotates the entire leg. After the leg is lifted to the highest position it can lift, it begins to fall. When it falls to the ground, the steering work of the servo is completed at this time, and it turns to the angle required to turn, completing the turning of one leg. After the first leg turns, the leg located in the diagonal direction of the first leg repeats the turning action of the first leg to turn; after the second leg turns, the other leg close to the forward direction starts to lift, repeats the turning action of the first leg to turn; after the fourth leg turns, the last leg repeats the turning action of the first leg to turn, completing the rotation of all legs. The steering mechanism 2 is based on the robot shape design and the arrangement of the four legs, so that flexible turning at a large angle can be achieved. During the entire turning process, it is ensured that there are always three legs in contact with the ground.

[0051] Based on the design of the robot shell and the arrangement of its four legs, the robot can achieve large-angle turns and right-angle turns in place. When making a right-angle turn, the robot moves straight and turns its right front leg and left hind leg 90° clockwise, and its left front leg and right hind leg 90° counterclockwise, thereby making a right-angle turn in place. During the right-angle turn, three legs are always in contact with the ground.

[0052] A groove is provided between each two adjacent double-axis steering gears on the middle plate 14 of the steering mechanism 2. Even if the robot makes a large-angle turn, the leg mechanism will not interfere. Therefore, there is a rotation space on both sides of the leg bracket 8, which can achieve a large-angle turn. Compared with the small-angle turn of the wheel type, the steering angle of this robot exceeds 120°, so it can adapt to various complex and changeable pipelines. At the same time, the steering mechanism 2 has a simple structure and a simplified steering method. By setting four double-axis steering gears to drive the rotation of the four legs respectively, the steering structure of the robot is simplified; by controlling the steering with four steering gears, it is simplified to achieve multi-angle steering.

[0053] The shell retracting function imitates the shell retracting of a tortoise, and the shell retracting function is realized by the combination of the motor 12 in the walking and posture changing mechanism 1 and the shape of the robot itself. The body 3 includes a body shell 15, which is connected to the steering gear upper shell 17 by bolts. The body shell 15 is hollow, and the outer diameter of the body shell 15 is larger than the outer diameter of the steering mechanism 2. The body shell 15, the middle plate 14 and the body bottom plate 13 constitute the body 3 of the robot. When the robot walks, the electric push rod 11 is in the first limit state, that is, the retracted state, and the length is locked and unchanged, and does not extend or retract, that is, the electric push rod 11 does not participate in the moving motion through the change of length, and is only used as a rod with a constant length. When the shell needs to be retracted, three of the legs in the walking and posture changing mechanism 1 are always in contact with the ground. The motor 12 drives one leg to lift off the ground, and the leg rotates counterclockwise to the groove of the middle plate 14. At this time, the motor 12 is just retracted into the cavity between the middle plate 14 and the fuselage bottom plate 13. While turning, the motor 12 drives the leg to start falling until the leg lands and touches the ground again. After the first leg turns and lands, the leg located in the diagonal direction of the leg repeats the above steps. After the leg turns and lands, the other two legs turn in turn, and finally all four legs are retracted into the groove. After the four legs are hidden under the robot's body shell 15, the electric push rods 11 on the four legs are extended at the same time to reach the second limit, that is, the extended state. At this time, the angle between the calf 4 and the ground is reduced, the height of the robot is reduced, and the center of gravity is lowered. Figure 9-10 shown.

[0054] The upper shell 15 of the body is designed to imitate a tortoise and is in a dome shape. When the shell is retracted, the robot is circular when viewed from above. At the same time, no matter which angle it turns, it will conform to the visual beauty.

[0055] The shell-shrinking function plays two roles: first, it has a strong camouflage ability during military reconnaissance; it can resist a certain degree of trampling during field operations; and second, it has a strong anti-impact ability when traveling in places with risks of falling objects.

[0056] The multi-morphological quadruped robot includes five morphologies and five posture control methods, which are specifically as follows:

[0057] The first type: normal walking posture: the normal walking posture is the walk gait and the trot gait. In this state, the height of the robot is at the highest, that is, the electric push rod 11 is at the shortest state. This state is suitable for walking on flat ground. The upper shell 15 of the body is provided with an access port, and objects can be placed inside the upper shell 15 to carry objects.

[0058] The second type: Swinging walking posture: When the robot is in the swinging walking posture, the steering mechanism 2 and the walking and posture changing mechanism 1 coordinate with each other. At this time, the forward direction is perpendicular to the motion plane of the crank-connecting rod rocker mechanism of the leg, such as Figure 7The front view direction shown is the forward direction. Steering is achieved by linkage with leg lifting. When the leg in the right front direction or the left front direction is lifted relative to the forward direction, it is driven by the dual-axis servo to rotate 20° to 30° counterclockwise or clockwise. When the leg falls, the leg in the left rear direction or the right rear direction begins to lift, and is driven by the dual-axis servo to rotate 20° to 30° in the forward direction. The action sequence of the four legs is the same as the walking gait, and the rotation angle is the same.

[0059] Preferably, the motor 12 is a waterproof motor, the dual-axis servo is a waterproof servo, the steering mechanism 2 and the fuselage upper shell 15 are externally provided with a waterproof shell for wrapping and coated with a waterproof coating (not shown in the figure). At this time, when the robot needs to pass through a deeper puddle, since the fuselage upper shell 15 is hollow, this posture can walk in the water. At this time, the four legs simultaneously perform the above-mentioned swinging walking posture, that is, the four legs are lifted up and turned at the same time.

[0060] The third type: Steering posture: driven by a dual-axis steering gear, the four legs complete the required rotation angles in turn according to the actual steering conditions, and can achieve steering at various angles. This form is suitable for complex roads and easy steering, such as pipelines.

[0061] Fourth: Half-recumbent posture: The four electric push rods 11 extend at the same time. In this embodiment, the four electric push rods 11 extend at the same time by 10 mm to lower the body 3. As the electric push rods 11 extend, the foot end trajectory changes, the highest point that the foot end can be lifted to becomes higher, and the passability becomes better, and normal walking posture, swinging walking posture and turning posture can be achieved. It can be used for outdoor shooting or reconnaissance, and can also be used for post-disaster search and rescue work. Fig.11 shown.

[0062] Fifth: Shell-shrinking posture: The electric push rod 11 is extended to the maximum length, the height of the robot is reduced, the center of gravity is lowered, and the robot lands steadily; the dual-axis steering gear drives the legs to rotate into the grooves of the middle plate 14, and the four legs are successively retracted under the shell, and the legs are hidden. This posture can be used to avoid the legs from being damaged when there are falling objects above. In this posture, walking and turning are impossible.

[0063] The polymorphic quadruped robot provided by the present invention includes three parts: a walking and posture changing mechanism 1, a steering mechanism 2 and a body shell 15. The body shell 15 and the steering mechanism 2 constitute the body 3 of the entire robot. The three parts together constitute the whole of the quadruped robot. The three parts are both independent of each other and cooperate with each other. The three parts work together to successfully complete the predetermined work. The biggest feature of the present invention is: 1. Through the ingenious design of the body 3 and the walking, the traveling process is stable, the turning performance is excellent, and a large angle of steering can be achieved. The load capacity of the body is enhanced, and a camera, a claw structure, a manipulator, and various sensors can be installed on the body shell 15 of the body. As a carrier, it works in some environments and can be applied to different work scenes. The robot has good versatility in application. It can be repaired in intricate pipelines, transport materials in disaster areas where rocks fall, and can also be used for field shooting. It is used for bulletproof transportation in the military. Second, through the design of the single-degree-of-freedom closed-chain leg structure and the selection of the DC motor 12 as the drive system control, there is only one prime mover, so its elliptical foot end trajectory is determined; at the same time, the mechanism has stronger support and carrying capacity, which is better than the environmental adaptability of the wheeled robot. Because it is a single-degree-of-freedom leg design, the walking control operation is simpler and easier to implement. It has more flexible turning ability and multi-form deformation ability. Third, because the steering mechanism 2 and the walking and posture change mechanism 1 are designed and coordinated, the dual-axis servo controls the rotation of the leg mechanism, and when a sharp turn is required, high-efficiency large-angle or small-angle steering is achieved. It has a variety of forms and can be adjusted according to the environment to improve obstacle crossing ability and work efficiency. Fourth, imitating the shell shrinking function of the tortoise, this robot has stronger defense than ordinary robots and has application capabilities in some dangerous areas. The present invention integrates multidisciplinary theories including mechanical design and electromechanical control to design a small-scale automated machinery, which is widely used in various occasions including military and pipelines.

Claims

1. A polymorphic quadruped robot, characterized in that: It includes a walking and posture changing mechanism, a steering mechanism and a fuselage shell, wherein the walking and posture changing mechanism is rotatably connected around the steering mechanism, and the fuselage shell is arranged on the top of the steering structure; Including normal walking posture, swinging walking posture, half-crouching posture, turning posture, and shell-shrinking posture; The walking and posture-changing mechanism includes four legs, which are symmetrically connected to the left and right sides of the steering mechanism, and are symmetrical relative to the front and rear sides of the steering mechanism. Each leg of the walking and posture-changing mechanism includes a motor, a calf, a cylindrical push rod, a crank, a connecting rod, a leg bracket, a rocker, a hollow rod and an electric push rod. The leg bracket is connected to the steering mechanism, the motor is fixed to the leg bracket, one end of the crank is connected to the output end of the motor, and the other end of the crank is rotatably connected to the connecting rod; the fixed end of the electric push rod is rotatably connected to the leg bracket, and the telescopic end of the electric push rod is rotatably connected to the front end of the calf; the two ends of the rocker are respectively rotatably connected to the fixed ends of the connecting rod and the electric push rod; the two ends of the hollow rod are respectively connected to the rod body of the connecting rod and the electric push rod; one end of the cylindrical push rod is rotatably connected to the inside of the cavity of the hollow rod, and the other end is rotatably connected to the calf near the front end of the calf; The steering mechanism comprises a fuselage bottom plate, an intermediate plate, four biaxial servos, four servo upper shells, and four servo lower shells. The servo upper shells and the servo lower shells are respectively mounted on the upper and lower sides of the intermediate plate by bolts in a centrally symmetrical manner, and the bottom of the servo lower shell is fixed to the fuselage bottom plate; the biaxial servo is fixed to the intermediate plate, and the two ends of the biaxial servo are respectively fixed to the servo upper shell and the servo lower shell; the leg bracket of the legs in the walking and posture changing mechanism is connected to the biaxial servo; a groove is provided between each two adjacent biaxial servos on the intermediate plate; The upper shell of the fuselage is connected to the upper part of the upper shell of the steering gear in the steering mechanism by bolts, and the outer diameter of the upper shell of the fuselage is larger than the outer diameter of the steering mechanism; the upper shell of the fuselage, the middle plate and the bottom plate of the fuselage constitute the body of the robot; The end of the lower leg is the foot end, which is cylindrical, and the center line of the cylinder is parallel to the ground; The two shaft ends of the dual-axis steering gear are respectively connected to the two ends of the leg bracket.

2. A polymorphic quadruped robot according to claim 1, characterized in that: The foot end is covered with rubber on the outside.

3. A polymorphic quadruped robot according to claim 1, characterized in that: The motor is a DC motor.

4. The polymorphic quadruped robot according to claim 1, characterized in that: Side plates are arranged on the sides of the groove.

5. The polymorphic quadruped robot according to claim 1, characterized in that: The upper shell is in a dome shape.

6. The polymorphic quadruped robot according to claim 1, characterized in that: The cross sections of the steering gear upper shell and the steering gear lower shell are L-shaped, and the dual-axis steering gear is placed in a cavity formed by the steering gear upper shell, the middle plate and the steering gear lower shell.

7. The polymorphic quadruped robot according to claim 1, characterized in that: The shank, cylindrical push rod, crank, connecting rod, rocker, hollow rod and electric push rod in each leg are of different lengths; the electric push rod is a pen-type electric push rod, and the motor is arranged inside the electric push rod.

8. A control method for realizing five postures using a multi-modal quadruped robot as claimed in claim 1, characterized in that: The details are as follows: The first type: normal walking posture: including walk gait and trot gait, in which trot gait: during walking, the four legs are divided into two groups, the two legs located on the diagonal are one group, and the walking pace of the two legs in the same group is consistent; the two groups of legs have a phase difference through the control of the motor adjustment, and during the movement, there is always a group of legs, that is, the two legs located in the same diagonal direction, in contact with the ground; walk gait: during walking, first lift the leg in the left front or right front direction relative to the walking direction, and lift the leg in the right rear or left rear direction relative to the walking direction at the same time as the first leg touches the ground, and lift the right front or left front leg at the same time as the second leg touches the ground, and finally lift the left rear or right rear leg. During the whole process, ensure that the upper leg touches the ground before the next leg can be lifted, that is, the two legs in the diagonal direction are lifted and lowered in the order of front and back relative to the walking direction, and three legs are always kept in contact with the ground during the walking process; The upper shell of the fuselage is provided with an access opening, and items can be placed inside the upper shell of the fuselage, thereby carrying objects; The second type: swing walking posture: In this state, the forward direction is perpendicular to the motion plane of the crank-connecting rod rocker mechanism of the leg. When the right front leg or the left front leg is lifted relative to the forward direction, it is driven by the dual-axis servo to rotate 20° to 30° counterclockwise or clockwise. When the leg falls, the left rear leg or the right rear leg begins to lift and is driven by the dual-axis servo to rotate 20° to 30° in the forward direction. The action sequence of the four legs is the same as the walking gait, and the rotation angle is the same. When walking in water, the four legs simultaneously perform the above-mentioned swinging walking posture, that is, the four legs are lifted and turned at the same time; The third type: Steering posture: driven by the dual-axis steering gear, the four legs complete the required rotation angles in turn according to the actual steering conditions; Fourth: Half-volt posture: Four electric push rods extend at the same time to lower the body. This state can achieve normal walking posture, swing walking posture and turning posture; Fifth: Shell-shrinking posture: The electric push rod is extended to its maximum length, the height of the robot is lowered, the center of gravity is lowered, and the dual-axis servo drives the legs to rotate into the groove of the middle plate. The four legs are retracted into the shell in turn, and the legs are hidden.

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