A flexible quadruped robot with discrete spine

Abstract

The application provides a flexible four-legged robot with a discrete spine, comprising a spine and four parallel elastic legs, the spine comprising a spine box, two spine rotary joints hinged at a distance on the spine box, and two SEA modules arranged in the spine box, each SEA module comprising a rotary drive motor and a second elastic accumulator, the output shaft of the rotary drive motor, the second elastic accumulator, and the spine rotary joint being sequentially connected, the four parallel elastic legs being arranged at four corners of the spine box in a rectangular distribution, and each two parallel elastic legs being hinged at a distance on a spine rotary joint, each parallel elastic leg being provided with a first elastic accumulator and a bottom provided with a foot bottom. The application imitates the posture of a cheetah when running, adopts a series elastic driver to drive the spine rotary joint to move, and combines a parallel elastic driver to drive the leg to move, so that the flexible four-legged robot has more biological structure flexibility and can adapt to complex and changeable scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible quadruped robots, in particular to a flexible quadruped robot with discrete spine. BACKGROUND

[0002] Robot technology is a popular research direction at the forefront of the moment, and has been widely used in all aspects of public work and life. Among them, mobile robots can replace manual work in dangerous environments to complete tasks such as exploration, transportation, and rescue, and have characteristics such as high efficiency and safety, and are highly concerned. Mobile robots can be divided into three categories according to their system movement modes; wheeled robots, tracked robots and legged robots. Compared with wheeled and tracked robots, legged robots have greater potential and can roam on different terrains like animals. Among them, the quadruped robot is the best choice among all legged robots related to the mobility and stability of movement. In 2005, Boston Dynamics first launched a three-foot-long, two-and-a-half-foot-wide, 240-pound quadruped robot named BigDog, which aims to assist soldiers in transporting supplies in different environments. BigDog has attracted widespread attention since its inception due to its superior balance and load capacity, pushing the research focus of quadruped robots to the top. At present, quadruped robots have been widely used in transportation, rescue and other fields due to their strong load capacity, high stability and ability to overcome most terrains.

[0003] The spine rotation joint structure of quadruped mammals can provide auxiliary power to complete various agile motion postures in various movements of quadruped animals due to its continuous configuration and the powerful muscles attached.

[0004] The trunk part of the current quadruped robot is mostly a rigid body structure, which lacks a flexible spine rotation joint similar to that of quadruped animals, and cannot assist the four limbs in jumping, running and turning movements through the flexibility and flexibility of the spine rotation joint to perform high-precision movements such as storage capacity, impact mitigation and posture adjustment.

[0005] Therefore, it is necessary to take quadruped animals as the simulation object to research bionic quadruped robots with flexible spine rotation joints, improve the mobility, stability and movement performance of quadruped robots in complex environments, which is a popular direction for the research and development of quadruped robots at present. SUMMARY

[0006] According to the deficiencies of the prior art, the purpose of the present application is to provide a flexible quadruped robot with discrete spine, which imitates the posture of a cheetah when running, uses a series elastic actuator to drive the spine rotation joint to move, and combines a parallel elastic actuator to drive the leg movement, which is more flexible and can adapt to complex and variable scenes.

[0007] To solve the above technical problems, the technical scheme adopted by the present application is:

[0008] A flexible four-legged robot with discrete spine, comprising:

[0009] The spine comprises a spine box, two spine rotation joints hingedly connected at a distance on the spine box, and two SEA modules arranged in the spine box, each SEA module comprising a rotation drive motor and a second elastic accumulator, the output shaft of the rotation drive motor, the second elastic accumulator, and the spine rotation joint being connected in sequence, the second elastic accumulator comprising a second elastic member, the output shaft of the rotation drive motor rotating to compress the first elastic member to store energy, and the second elastic member extending to drive the spine rotation joint to rotate to release energy.

[0010] Four parallel elastic leg feet are arranged at the four corners of the spine box in a rectangular distribution, and each two parallel elastic leg feet are hingedly connected at a distance on one spine rotation joint, and a first elastic accumulator is arranged on each parallel elastic leg foot and a foot bottom is arranged at the bottom.

[0011] Further, the second elastic accumulator further comprises a SEA lower half and a SEA upper half, the SEA lower half is fixed on the output shaft of the rotation drive motor, the SEA upper half is sleeved on the SEA lower half and coaxially arranged, a second elastic member is arranged between the SEA upper half and the SEA lower half, and the spine rotation joint and the SEA upper half are fixed.

[0012] Further, a bearing is arranged between the SEA upper half and the SEA lower half.

[0013] Further, the SEA lower half comprises a first bottom plate and a plurality of first fins arranged in a ring shape outside the first bottom plate, and a first connecting column is arranged on each first fin.

[0014] The SEA upper half comprises a second bottom plate and a plurality of second fins arranged in a ring shape outside the second bottom plate, a second connecting column is arranged on each second fin, an output convex shaft is arranged on the second bottom plate, and the output convex shaft and the spine rotation joint are fixed.

[0015] The plurality of first connecting columns and the plurality of second connecting columns are arranged in a ring shape and are staggered, and each group of adjacent first connecting columns and second connecting columns is connected by a second elastic member.

[0016] Further, the SEA modules connected by the two spine rotation joints are diagonally arranged inside the spine box.

[0017] Further, two encoder modules are further included, each of which is connected with a spine rotary joint, and the two encoder modules are diagonally arranged inside the spine box.

[0018] Further, the parallel elastic leg foot comprises a hip joint driving motor, a thigh connecting piece, a thigh driving motor, a knee joint connecting piece, a shank driving motor, a thigh and a shank, the hip joint driving motor is fixed on the spine rotary joint, the thigh connecting piece is fixed with an output shaft of the hip joint driving motor, the thigh driving motor is arranged on the thigh connecting piece, the knee joint connecting piece is fixed on an output shaft of the thigh driving motor, the shank driving motor is fixed on the knee joint connecting piece, the thigh is fixed on the shank driving motor, and an output shaft of the shank driving motor is fixed with the shank.

[0019] Further, the thigh connecting piece comprises a first connecting flange and a first fixing piece fixed on the first connecting flange, and the first fixing piece and the first connecting flange are vertically arranged.

[0020] Further, the thigh is a hollow structure, the thigh is internally provided with a shank connecting piece and a connecting rod, the shank connecting piece is fixed with an output shaft of the shank driving motor, one end of the connecting rod is hingedly connected with the shank connecting piece, the other end is hingedly connected with the shank, and the connecting rod is provided with a first elastic accumulator.

[0021] Further, the first elastic accumulator comprises a first elastic piece, a sliding piece and a guide rail, the first elastic piece is sleeved on the connecting rod and fixed at one end on the connecting rod and at the other end on the sliding piece, the guide rail is fixed on the inner side of the first thigh shell or the second thigh shell, and the sliding piece is sleeved on the connecting rod and arranged on the guide rail.

[0022] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0023] The present application provides a flexible quadruped robot with a discrete spine, a first elastic accumulator is arranged on each parallel elastic leg foot, and a foot bottom is arranged at the bottom to form a PEA leg foot structure, a SEA module drives the flexible movement of a spine rotary joint to form a discrete SEA spine rotary joint structure, not only can the SEA module control the curling and stretching posture of the spine rotary joint and the effective compression and release of the first elastic accumulator to realize the rapid movement of the quadruped robot and improve the mobility of the robot, but also can the discrete SEA spine rotary joint structure and the PEA leg foot structure be combined to provide the quadruped robot with flexibility.

[0024] And the flexible quadruped robot with discrete spine provided by the application is a two-degree-of-freedom discrete spine, the two-degree-of-freedom discrete spine has better speed performance, the attack angle of the foot bottom to the ground is larger, and the attack angle is more conducive to the conversion of driving force into forward power, the change of the center of mass of the whole machine under the control of the spine is smaller, so that the movement process is more stable, and the quadruped robot with the two-degree-of-freedom spine has the best obstacle crossing ability. Based on the above advantages, while considering the degree-of-freedom redundancy of the continuous spine, it is difficult to establish an accurate spine kinematics and dynamics model, leading to subsequent control difficulties, and the two-degree-of-freedom discrete spine is selected as the trunk part of the quadruped robot.

[0025] The application can adapt to complex and variable scenes, such as rock piles, collapsed houses, rugged mountain roads, soft grasslands and the like. The SEA module (SEA, series elastic actuator) used in the application absorbs part of the energy first and then releases and transmits it to the other end, i.e. the spine rotating joint, when output torque or external impact is generated, so that the output torque is more stable and will not suddenly change, and the reaction force impact on the rotating drive motor when the limbs contact the ground is reduced, improving the reliability of the spine rotating joint mechanism. In order to improve the motion performance of the quadruped robot, the first elastic energy accumulator is arranged on the parallel elastic leg foot, the first elastic energy accumulator can store part of the gravitational potential energy and release it when needed, improve the energy utilization rate, and also can release by actively compressing the first elastic energy accumulator, improve the instantaneous output torque. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings described herein are used to provide further understanding of the application, and form a part of the application. The illustrative embodiments of the application and their descriptions are used to explain the application, and do not constitute an improper limitation on the application. In the drawings:

[0027] Figure 1 It is a schematic diagram of the overall structure of the application;

[0028] Figure 2 It is a schematic diagram of the structure of the parallel elastic leg foot of the application;

[0029] Figure 3 It is a schematic diagram of the structure of the spine of the application;

[0030] Figure 4 It is a schematic diagram of the structure of the connection of each drive motor of the parallel elastic leg foot of the application;

[0031] Figure 5 It is a schematic diagram of the structure of the first elastic energy accumulator arranged in the thigh of the application;

[0032] Figure 6 It is a layout schematic diagram of the SEA module and the encoder module of the application;

[0033] Figure 7 Layout diagram of power board module, IMU module and main control board of the application;

[0034] Figure 8 Structure diagram of SEA module of the application;

[0035] Figure 9 Structure diagram of box switch module of the application;

[0036] Figure 10 Structure diagram of spinal rotation joint of the application;

[0037] Figure 11 Structure diagram of battery module of the application.

[0038] Among them, 100, spine; 110, spine box; 111, box upper cover; 112, switch hole; 120, SEA module; 121, rotation driving motor; 122, second elastic energy accumulator; 123, second elastic member; 124, SEA lower half; 1241, first bottom plate; 1242, first fin; 1243, first connecting column; 125, SEA upper half; 1251, second bottom plate; 1252, second fin; 1253, second connecting column; 1254, output convex shaft; 1255, limiting column; 126, bearing; 127, rotation driving motor mounting rack; 130, box switch module; 131, switch slider; 132, third elastic member; 133, switch button; 134, limiting socket; 140, spinal rotation joint; 141, first side plate; 142, middle plate; 1421, boss clamping groove; 143, second side plate; 1431, arc-shaped limiting hole; 144, dust cover; 150, battery module; 151, battery cover; 153, large-capacity lithium battery; 152, switch; 160, encoder module; 161, encoder mounting rack; 162, encoder; 170, main control board;

[0039] 200, parallel elastic leg foot; 201, first elastic energy accumulator; 2011, first elastic member; 2012, sliding member; 2013, guide rail; 202, foot bottom; 203, hip joint driving motor; 204, upper leg connecting piece; 2041, first connecting flange; 2042, first fixing member; 205, upper leg driving motor; 206, knee joint connecting piece; 207, lower leg driving motor; 208, upper leg; 2081, first upper leg shell; 2082, second upper leg shell; 2083, lower leg connecting piece; 2084, connecting rod; 209, lower leg. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described in the description of the present application in conjunction with the accompanying drawings.

[0041] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", and the like can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0042] The present application provides a flexible four-legged robot with a discrete spine, as shown in Figures 1-11 The flexible four-legged robot with a discrete spine includes a spine 100, four parallel elastic leg feet 200, and two SEA modules 120.

[0043] The spine 100 includes a spine box 110, two spine rotation joints 140 hingedly connected at a certain distance on the spine box 110, and two SEA modules 120 arranged in the spine box 110. Each SEA module 120 includes a rotation driving motor 121 and a second elastic accumulator 122. The output shaft of the rotation driving motor 121, the second elastic accumulator 122, and the spine rotation joint 140 are connected in series to form a series elastic driver. The second elastic accumulator 122 includes a second elastic member 123. The output shaft of the rotation driving motor 121 rotates to compress the second elastic member 123 to store energy, and the second elastic member 123 expands to drive the spine rotation joint 140 to rotate to release energy.

[0044] The four parallel elastic leg feet 200 are arranged in a rectangular distribution at the four corners of the spine box 110. Every two parallel elastic leg feet 200 are hingedly connected at a certain distance on a spine rotation joint 140. Each parallel elastic leg foot 200 is provided with a first elastic accumulator 201 and a foot bottom 202 at the bottom to form a parallel elastic driver.

[0045] In the related art, the torso part of the quadruped robot is mostly a rigid body structure, lacks a flexible spine rotating joint 140 similar to a quadruped animal, and cannot assist the limbs in high-precision movements such as saving energy, reducing impact, and adjusting posture in jumping, running, and turning through the flexibility and flexibility of the spine rotating joint 140 like a quadruped animal. The present application provides a flexible quadruped robot with a discrete spine, a first elastic accumulator 201 is arranged on each parallel elastic leg 200, and a foot bottom 202 is arranged at the bottom to form a PEA leg structure, and the SEA module 120 drives the flexible movement of the spine rotating joint 140 to form a discrete SEA spine rotating joint structure. Not only can the SEA module 120 control the flexion and extension posture of the spine rotating joint 140 and the effective compression and release of the first elastic accumulator 201 to realize the rapid movement of the quadruped robot and improve the mobility of the robot, but also can provide flexibility for the quadruped robot in combination with the discrete SEA spine rotating joint 140 structure and the PEA leg structure.

[0046] And the flexible quadruped robot with a discrete spine provided by the present application is a two-degree-of-freedom discrete spine 100, which has better speed performance; the attack angle of the foot bottom 202 to the ground is larger, which is more conducive to the conversion of driving force into forward power; the change of the center of mass of the whole machine under the control of the spine 100 is smaller, making the movement process more stable; the quadruped robot with a two-degree-of-freedom spine 100 has the best obstacle crossing ability. Based on the above advantages, while considering the degree-of-freedom redundancy of the continuous spine 100, it is difficult to establish an accurate kinematics and dynamics model of the spine 100, leading to subsequent control difficulties, the present application selects a two-degree-of-freedom discrete spine 100 as the torso part of the quadruped robot.

[0047] The present application can adapt to complex and variable scenes, such as piles of stones, collapsed houses, rugged mountain roads, soft grasslands and the like. The SEA module 120 (SEA, series elastic actuator) used in the present application will first absorb a part of the energy when output torque or external impact is applied, and then release and transmit it to the other end, i.e. the spine rotating joint 140, so that the output torque is more stable and will not change suddenly, and at the same time, the reaction force impact on the rotating drive motor 121 when the limbs contact the ground is reduced, improving the reliability of the spine rotating joint 140 mechanism. In order to improve the motion performance of the quadruped robot, the present application adopts a first elastic accumulator 201 arranged on the parallel elastic leg 200, which can store a part of the gravitational potential energy and release it when needed, improving the energy utilization rate, and also can release by actively compressing the first elastic accumulator 201, improving the instantaneous output torque.

[0048] The SEA module 120 will be described in detail below.

[0049] As shown in Figures 6-8 The rotating driving motor 121 is installed inside the spine box 110 through the rotating driving motor 121 mounting frame. The second elastic accumulator 122 further comprises a SEA lower half 124 and a SEA upper half 125. The SEA lower half 124 is fixed on the output shaft of the rotating driving motor 121. The SEA upper half 125 is sleeved on the SEA lower half 124 and connected with the SEA lower half 124 through the second elastic element 123. The spine rotating joint 140 and the SEA upper half 125 are fixed. The output shaft of the rotating driving motor 121 rotates to output torque to the SEA lower half 124. The SEA lower half 124 compresses the second elastic element 123 to store energy. The second elastic element 123 stretches to output torque to the SEA upper half to drive the spine rotating joint 140 to rotate to release energy.

[0050] The second elastic accumulator 122 further comprises a SEA lower half 124 and a SEA upper half 125. The SEA lower half 124 is fixed on the output shaft of the rotating driving motor 121. A plurality of first connecting columns 1243 are annularly distributed on the SEA lower half 124. The SEA upper half 125 is sleeved on the SEA lower half 124 and coaxially arranged. A plurality of second connecting columns 1253 are annularly distributed on the SEA upper half 125. A second elastic element 123 is arranged between each first connecting column 1243 and a second connecting column 1253. The spine rotating joint 140 and the SEA upper half 125 are fixed.

[0051] The working principle of the SEA module 120 is that when the output shaft of the rotary drive motor 121 rotates, the torque is first transmitted to the SEA lower half 124 and drives it to rotate. Since the SEA upper half 125 is connected to the spinal column rotary joint 140 and the parallel elastic leg 200 thereon, the inertia of the load makes the SEA upper half 125 remain stationary, which compresses the second elastic member 123 in the SEA module 120 and causes it to deform from the normal state to the stressed state. In the normal state, each second elastic member 123 forms an angle with the center line of the output shaft, and at this time, the tension on each second elastic member 123 is the same, and the interaction keeps the SEA upper half 125 and the SEA lower half 124 in a stable state. The second elastic member 123 selected by the application is slightly longer than the initial length when the SEA reaches the mechanical limit, i.e., when the SEA upper half 125 and the SEA lower half 124 come into contact, the center of the second connecting column 1253 and the first connecting column 1243 forms an angle with the center line of the SEA output shaft. At this time, the second elastic member 123 is slightly longer than the initial length, which ensures that the second elastic member 123 is in a stretched state at any position to prevent the hook from loosening. In the stressed state, the second elastic members 123 are stretched and the second elastic members 123 are compressed, and the elastic force generated by the stretched second elastic members 123 is much greater than that generated by the compressed second elastic members 123. Since the second elastic members 123 are arranged in a circumferential array, the entire second elastic member 123 group outputs torque in the same direction. Based on the above characteristics, the SEA module 120 can absorb a portion of the energy when the output torque or external impact is transmitted to the other end, making the output torque more stable and not changing suddenly, and also reducing the impact of the reaction force on the rotary drive motor 121 when the limbs contact the ground, improving the reliability of the spinal column rotary joint 140.

[0052] Specifically, as shown in Figure 8 The SEA lower half 124 includes a first bottom plate 1241 and a plurality of first fins 1242 arranged in a ring outside the first bottom plate 1241, and each first fin 1242 is provided with a first connecting column 1243.

[0053] The SEA upper half 125 includes a second bottom plate 1251 and a plurality of second fins 1252 arranged in a ring outside the second bottom plate 1251, and each second fin 1252 is provided with a second connecting column 1253. The second bottom plate 1251 is provided with an output convex shaft 1254, which is fixed to the spinal column rotary joint 140 by bolts, so that the spinal column rotary joint 140 forms a rotary pair relative to the spinal column box 110.

[0054] The first connecting columns 1243 and the second connecting columns 1253 are arranged in a circumferential staggered manner, and each group of adjacent first connecting columns 1243 and second connecting columns 1253 is connected by a second elastic member 123.

[0055] The plurality of second elastic members 123 are sequentially connected to form an elastic ring, and adjacent two second elastic members 123 are connected by a hanging ring which is hung on the first connecting column 1243 or the second connecting column 1253.

[0056] In the embodiment of the application, a first connecting column 1243 is annularly distributed on the upper half of the SEA 125, a second connecting column 1253 is annularly distributed on the lower half of the SEA 124, and a second elastic member 123 is connected between the upper half of the SEA 125 and the lower half of the SEA 124.

[0057] The SEA modules 120 connected by the two spinal column rotary joints 140 are diagonally arranged inside the spinal column box body 110, so as to uniformly distribute the mass of the spinal column 100 and prevent the generation of overturning moment due to the excessive mass of one side of the spinal column 100.

[0058] In the application, a bearing 126 is arranged between the upper half of the SEA 125 and the lower half of the SEA 124, so as to reduce the friction during rotation and facilitate the coaxiality of the output shaft of the rotary driving motor 121 and the output convex shaft 1254 of the other side of the lower half of the SEA 124. The bearing 126 can be a deep groove ball bearing 126.

[0059] The application further comprises two encoder modules 160, as shown in Figure 6 and Figure 7 Each encoder module 160 is connected with one spinal column rotary joint 140, and the two encoder modules 160 are diagonally arranged inside the spinal column box body 110.

[0060] The encoder module 160 comprises an encoder mounting frame 161 fixed inside the spinal column box body 110 and an encoder 162 arranged on the encoder mounting frame 161, and the output shaft of the encoder 162 is fixed with the spinal column rotary joint 140.

[0061] Specifically, the spinal column rotary joint 140 is provided with a passive output shaft, and two encoders 162 are arranged on the inside of the spinal column box body 110, and the output shaft of the encoder 162 is a D-shaped shaft which is fixed by being pressed through a D-shaped hole on the passive output shaft and an M bolt, so as to prevent the slight shaking of the output shaft of the encoder 162 due to the machining error and affect the measurement of the angle of the spinal column rotary joint 140. The shell of the encoder 162 is threadedly connected with the encoder mounting frame 161 and is fixed together on the inside wall of the spinal column box body 110.

[0062] The parallel elastic leg-foot 200 will be described in detail below.

[0063] In the present application, as shown in Figures 2-5 The parallel elastic leg-foot 200 includes a hip joint driving motor 203 fixed on the spine rotary joint 140, a thigh connecting piece 204, a thigh driving motor 205, a knee joint connecting piece 206, a shank driving motor 207, a thigh 208 and a shank 209. The thigh connecting piece 204 is fixed with an output shaft of the hip joint driving motor 203. The thigh driving motor 205 is arranged on the thigh connecting piece 204. The knee joint connecting piece 206 is fixed on an output shaft of the thigh driving motor 205. The shank driving motor 207 is fixed on the knee joint connecting piece 206. The thigh 208 is fixed on the shank driving motor 207. An output shaft of the shank driving motor 207 is fixed with the shank 209.

[0064] During the movement, the output shaft of the hip joint driving motor 203 connects the thigh connecting piece 204, drives the thigh driving motor 205, the shank driving motor 207, the thigh 208 and the shank 209 to complete the supination and pronation movement in the parallel elastic leg-foot 200, and plays a role in steering and adjusting the posture in the movement of the four-legged robot. The output shaft of the thigh driving motor 205 connects the knee joint connecting piece 206, drives the shank driving motor 207, the thigh 208, the shank driving motor 207 and the shank 209 to rotate together. The output shaft of the shank driving motor 207 is fixed with the shank 209, and drives the shank 209 to move.

[0065] The thigh driving motor 205 and the thigh 208 form a thigh module, and the shank driving motor 207 and the shank 209 form a shank module,

[0066] As shown in Figure 3 The thigh connecting piece 204 includes a first connecting flange 2041 and a first fixing piece 2042 fixed on the first connecting flange 2041. The first fixing piece 2042 and the first connecting flange 2041 are arranged vertically. The first connecting flange 2041 is fixed with the output shaft of the hip joint driving motor 203. The first fixing piece 2042 is fixed with the thigh driving motor 205, so that the axis of the hip joint driving motor 203 and the axis of the thigh driving motor 205 are arranged vertically, and the thigh driving motor 205, the shank driving motor 207, the thigh 208 and the shank 209 complete the supination and pronation movement relative to the hip joint driving motor 203.

[0067] In an embodiment of the present application, as shown in Figure 4 Two first fixing pieces 2042 are arranged on the first connecting flange 2041 at a certain distance. The thigh driving motor 205 is arranged between the two first fixing pieces 2042 and locked by bolts.

[0068] As shown in Figure 4As shown, the knee joint connector 206 is a second connecting flange, one side of which is fixed with the output shaft of the thigh driving motor 205, and the other side is fixed with the shank driving motor 207. Specifically, one side of the second connecting flange is provided with an annular protrusion or a disc-shaped protrusion, which is fixed with the output shaft of the thigh driving motor 205 through bolts, and the outer ring of the other side of the second connecting flange is fixed with the shank driving motor 207.

[0069] The thigh 208 is a hollow structure, as shown in the figure. Figure 5 As shown, the thigh 208 includes a first thigh shell 2081 and a second thigh shell 2082, which are clamped and then fixed with the shank driving motor 207 through bolts. In order to reduce the mass of the thigh 208 as much as possible, the inner walls of the first thigh shell 2081 and the second thigh shell 2082 are reinforced to improve the overall strength, and at the same time, spaces are left for the sliding member 2012 and the guide rail 2013. The guide rail 2013 is connected to the inner side of the first thigh shell 2081 or the second thigh shell 2082 through threads.

[0070] Since the first thigh shell 2081 and the second thigh shell 2082 of the thigh 208 need to act as a rack for the internal connecting rod 2084 mechanism, they need to withstand the reaction force from the ground during the movement of the quadruped robot, and in order to make the overall structure as compact as possible, they need to be designed as light and thin as possible to leave more space for the internal mechanism, the first thigh shell 2081 and the second thigh shell 2082 are made of aluminum alloy material.

[0071] The shank 209 of the present application does not need to add other structures inside, and has sufficient width and thickness, and is made of high-performance nylon material, which can meet the use requirements while reducing the overall weight of the machine.

[0072] The sole 202 of the present application directly contacts the ground and is made of flexible rubber material, which can improve the adaptability to the terrain and reduce the ground impact.

[0073] In the present application, as shown in the figure, Figure 5 As shown, the thigh 208 is provided with a shank connector 2083 and a connecting rod 2084, the shank connector 2083 is fixed with the output shaft of the shank driving motor 207, one end of the connecting rod 2084 is hinged with the shank connector 2083, the other end is hinged with the shank 209, and the connecting rod 2084 is provided with a first elastic accumulator 201. The shank driving motor 207 drives the shank connector 2083 to rotate, and then drives the connecting rod 2084 to rotate, so as to drive the shank 209 to rotate, when the connecting rod 2084 rotates relative to the shank connector 2083, the first elastic accumulator 201 is compressed to store energy, and when the first elastic accumulator 201 releases energy, the adaptability of the parallel elastic leg-foot 200 to the terrain and the reduction of the ground impact can be improved.

[0074] Specifically, the first elastic accumulator 201 comprises a first elastic member 2011, a sliding member 2012 and a guide rail 2013, the first elastic member 2011 is sleeved on the connecting rod 2084 and fixed at one end on the connecting rod 2084 and at the other end on the sliding member 2012, the guide rail 2013 is fixed on the inner side of the first thigh shell 2081 or the second thigh shell 2082, the sliding member 2012 is sleeved on the connecting rod 2084 and arranged on the guide rail 2013, and the lower leg 209 is hinged to the first thigh shell 2081 or the second thigh shell 2082, so that the lower leg connecting piece 2083, the connecting rod 2084, the lower leg 209 and the first thigh shell 2081 or the second thigh shell 2082 form a parallel four-bar linkage mechanism. At this time, the parallel four-bar linkage mechanism and the lower leg driving motor 207 constitute a parallel elastic actuator (PEA) module.

[0075] During the movement of the parallel four-bar linkage mechanism, the movement of the connecting rod 2084 can be divided into axial movement and normal movement along the first thigh shell 2081 or the second thigh shell 2082, and since the guide rail 2013 is fixed to the first thigh shell 2081 or the second thigh shell 2082, the sliding member 2012 is sleeved on the connecting rod 2084 and arranged on the guide rail 2013, so that the sliding member 2012 can only move along the direction of the guide rail 2013 and cannot move normally with the connecting rod 2084, and therefore during the movement of the leg, the first elastic member 2011 on the connecting rod 2084 will be compressed and deformed by the upper sliding member 2012. The first elastic member 2011 and the lower leg driving motor 207 are in a parallel relationship similar to the muscle-skeletal system, and when the joint of the lower leg 209 is bent inward, the first elastic member 2011 is compressed to store energy, similar to muscle contraction, and when the joint of the lower leg 209 is stretched outward, the first elastic member 2011 releases the stored potential energy to assist the lower leg driving motor 207 to generate greater driving force. In actual use, the parallel elastic leg-foot 200 has the following characteristics:

[0076] (1) During running, the swing of the parallel elastic leg-foot 200 makes the foot bottom 202 touch the ground, and the reverse impact force transmitted by the ground is transmitted to the lower leg driving motor 207 through the connecting rod 2084, and in this process, the rotation of the lower leg driving motor 207 drives the compression of the first elastic member 2011, so that the first elastic member 2011 absorbs part of the impact force and stores it as elastic potential energy, reduces the burden of the lower leg driving motor 207 and improves the energy utilization rate.

[0077] (2) In a static state, when the quadruped robot is in a standing posture, the weight of the robot is transmitted to the legs, causing the parallel elastic leg-foot 200 to naturally bend, and at the same time, the first elastic member 2011 is compressed, causing part of the gravitational potential energy to be converted into elastic potential energy. In a non-static state, the gravitational potential energy and the elastic potential energy are also converted into each other, further improving the energy utilization rate.

[0078] (3) In addition to passive energy storage, when facing complex environment, the calf driving motor 207 can also be used to actively rotate the compressed first elastic member 2011, reserve elastic potential energy in advance, and then quickly reverse to release to improve the instantaneous pushing force, so that the quadruped robot obtains higher initial speed or jumping height.

[0079] The first elastic member 2011 is a spring, the sliding member 2012 is provided with a linear bearing 126, and the linear bearing 126 is sleeved on the connecting rod 2084. The connecting rod 2084 is provided with an upper connecting piece and a lower connecting piece at both ends, respectively. One end of the spring is fixed with the upper connecting piece, and the other end is fixed with the linear bearing 126. The upper connecting piece is hinged with the calf connecting piece 2083, and the lower connecting piece is hinged with the calf 209.

[0080] As shown in Figure 9 The spine box body 110 is provided with a box upper cover 111, and the box upper cover 111 is provided with a box switch module 130. The box switch module 130 is used for opening the box upper cover 111 relative to the spine box body 110. The box switch module 130 includes a switch sliding block 131, a third elastic member 132 and a switch button 133.

[0081] The switch button 133 is arranged on the switch hole 112, and the switch sliding block 131 is arranged inside the spine box body 110. One end of the third elastic member 132 is arranged on the switch button 133, and the other end is arranged on the switch sliding block 131. The box upper cover 111 is arranged between the switch sliding block 131 and the side wall of the spine box body 110. When the switch button 133 is pressed, the third elastic member 132 can push the switch sliding block 131, facilitating the removal of the box upper cover 111. When the switch button 133 is pulled out, the switch sliding block 131 can block the box upper cover 111. In order to limit the moving direction of the switch sliding block 131, the inside of the spine box body 110 is provided with a limiting clamping hole 134, and the switch sliding block 131 is arranged in the limiting clamping hole 134.

[0082] As shown in Figure 10 The spine rotating joint 140 is a "F" shaped structure, including a first side plate 141, an intermediate plate 142 and a second side plate 143 connected in sequence. The first side plate 141 on the same side of the rotating drive motor 121 is provided with an arc-shaped limiting hole 1431, and the side wall of the spine box body 110 is provided with a limiting column 1255 which slides up and down in the arc-shaped limiting hole 1431, so that the first spine rotating joint 140 can only swing up and down within a certain angle relative to the spine box body 110. In order to prevent dust from entering the spine box body 110, the spine rotating joint 140 is provided with a dust cover 144 for dust prevention.

[0083] The intermediate plate 142 is provided with a plurality of boss clamping grooves 1421 for fixing the hip joint motor.

[0084] The application further comprises a power board module, the power board module comprises two power boards, carries an IPT chip, meets the PD high-power power supply of the ROCK Pi module, each power board can provide motor power supply and a communication interface on two parallel elastic leg feet 200 at the same time, and an interface connected with the motor switch 152 is reserved, the motor switch 152 is conveniently accessed, considering that there are many motors, the power board module is designed to pass through A large current, so that overload is prevented, and the two power board modules are installed above the ROCK Pi and connected with the upper cover of the spine box body 110 through threads.

[0085] The IMU module of the application can reach 50 Hz, can transmit angle, angular velocity and linear acceleration data, and has an accuracy of 0.01°, supports two communication protocols of Bluetooth and UART, and is installed at the center of the upper cover of the spine box body 110 to detect the posture of the spine 100 in the movement process in real time.

[0086] The control board module of the application selects two ROCK Pis as the main control board 170 of the system, the CPU of the ROCK Pis adopts a Rockchip RK3399, the bit processor of the Rockchip RK3399 has a main frequency of 1.8 GHz, the memory is 4 GB, the ROCK Pis carry a ROS system, have various external interfaces, adapt to various communication protocols, and are sufficient to meet the use of the GO-M8010-6, the two ROCK Pis are installed at the bottom of the spine box body 110 and are diagonally arranged, and control two parallel elastic leg feet 200 on one side respectively, and the two ROCK Pi modules communicate through a TCP / IP protocol.

[0087] As shown in Figure 7 and Figure 11 The application further comprises a battery module 150, the battery module 150 comprises a battery cover 151, a switch 152 and a large-capacity lithium battery 153, the battery cover 151 is arranged on the upper cover 111 of the box body, and the two large-capacity lithium batteries 153 are arranged in the battery cover 151.

[0088] The two large-capacity lithium batteries 153 serve as a power supply source, the rated current of each battery is A, and the power lines of each battery pass through the through holes reserved in the upper cover 111 of the box body and supply power to two parallel elastic leg feet 200 on one side and a SEA module 120 with a serial elastic driver. To ensure safety, two switches 152 are installed above the battery cover 151, one of the switches 152 is connected with the outputs of the two batteries as a main switch 152, and the other switch 152 is a motor switch 152 and only controls the power supply of all drive motors, so that only the motor power supply is disconnected in an unexpected situation, and the control board module is prevented from suddenly being powered off.

[0089] The rotation driving motor 121, the hip joint driving motor 203, the upper leg driving motor 205 and the lower leg driving motor 207 selected in the application are GO-M8010-6 motors of Yushu Technology, the size is 96.5mm x 92.5mm x 42.3mm, the weight is about 530g, the maximum torque can reach 23.7NM, and the maximum rotating speed can reach 30rad / s (24V power supply).

[0090] In the embodiment of the application, in order to reduce the inertia of joint rotation as much as possible, the connecting pieces between the motors are made of high-performance nylon material d and printed, which play a role in connecting and transmitting torque. In addition, the connecting pieces are provided with bosses to provide mechanical limiting for the rotation of each joint.

[0091] In summary, when the flexible quadruped robot with discrete spine works, firstly, the series elastic actuator (SEA module 120) on both sides of the spine box 110 connects the two end spine rotating joints 140, and the other end of each spine rotating joint 140 is connected to the respective two parallel elastic legs; after all the driving motors are powered on, the series elastic actuator (SEA module 120) module drives the spine rotating joint 140 to rotate, so that the quadruped robot realizes the curling and stretching motion of the bionic spine 100 structure. At the same time, among the four parallel elastic legs 200, the hip joint driving motor 203 drives the upper leg driving motor 205 and the lower leg driving motor 207 to complete the leg mechanism inside-out turning motion, which plays a role in steering and adjusting the posture in the quadruped robot motion; the output shaft of the upper leg driving motor 205 is connected to the housing of the lower leg driving motor 207, which drives the upper leg 208 and the lower leg 209 to rotate together; the output shaft of the lower leg driving motor 207 is connected to the parallel four-bar mechanism inside the upper leg 208, which drives the lower leg 209 joint to move. By controlling the curling and stretching posture of the spine 100 and the effective compression and release of the second elastic member 123 of the leg, the bionic quadruped robot designed in the application not only can realize the rapid motion of the quadruped robot, but also can provide flexibility for the quadruped robot by combining the discrete SEA spine 100 structure and the PEA leg structure, so that the quadruped robot can adapt to various complex scenes and improve the complex scene adaptability of the quadruped robot.

[0092] Obviously, those skilled in the art can make various modifications and variations to the application without departing from the spirit and scope of the application. Thus, if these modifications and variations of the application belong to the scope of the claims of the application and their equivalent technologies, the application also intends to include these modifications and variations.

Claims

1. A flexible quadruped robot with a discrete spine, characterized in that, include: The spine includes a spine housing, two spinal rotation joints hinged at a certain distance on the spine housing, and two SEA modules disposed in the spine housing. Each SEA module includes a rotation drive motor and a second elastic accumulator. The output shaft of the rotation drive motor, the second elastic accumulator, and the spinal rotation joints are connected in sequence. The second elastic accumulator includes a second elastic element. The output shaft of the rotation drive motor rotates and compresses the second elastic element to store energy. The extension of the second elastic element causes the spinal rotation joints to rotate and release energy. Four parallel elastic legs are arranged in a rectangular pattern at the four corners of the spinal box. Each pair of parallel elastic legs is hinged to a spinal rotation joint at a certain distance. Each parallel elastic leg is provided with a first elastic energy storage device and a foot sole at the bottom. The second elastic accumulator also includes a lower half of SEA and an upper half of SEA. The lower half of SEA is fixed on the output shaft of the rotary drive motor. The upper half of SEA is sleeved on the lower half of SEA and coaxially arranged. A second elastic element is provided between the upper half of SEA and the lower half of SEA. The spinal rotation joint is fixed to the upper half of SEA. The lower half of the SEA includes a first chassis and a plurality of first fins distributed in a ring on the outer side of the first chassis, and each first fin is provided with a first connecting post. The upper half of the SEA includes a second chassis and a plurality of second fins distributed in a ring on the outer side of the second chassis. Each second fin is provided with a second connecting post. The second chassis is provided with an output cam shaft, which is fixed to the spinal rotation joint. Multiple first connecting posts and multiple second connecting posts are arranged circumferentially staggered, and each pair of adjacent first connecting posts and second connecting posts are connected by a second elastic member.

2. The flexible quadruped robot with a discrete spine according to claim 1, characterized in that: A bearing is provided between the upper half and the lower half of the SEA.

3. The flexible quadruped robot with a discrete spine according to claim 1, characterized in that: The two spinal rotation joints are respectively connected to the SEA modules, which are arranged diagonally inside the spinal box.

4. The flexible quadruped robot with a discrete spine according to claim 1, characterized in that: It also includes two encoder modules, each of which is connected to a spinal rotation joint. The two encoder modules are arranged diagonally inside the spinal housing.

5. The flexible quadruped robot with a discrete spine according to claim 1, characterized in that: The parallel elastic leg includes a hip joint drive motor, a thigh connector, a thigh drive motor, a knee connector, a calf drive motor, a thigh, and a calf. The hip joint drive motor is fixed to the spinal rotation joint. The thigh connector is fixed to the output shaft of the hip joint drive motor. The thigh drive motor is mounted on the thigh connector. The knee connector is fixed to the output shaft of the thigh drive motor. The calf drive motor is fixed to the knee connector. The thigh is fixed to the calf drive motor. The output shaft of the calf drive motor is fixed to the calf.

6. The flexible quadruped robot with a discrete spine according to claim 5, characterized in that: The thigh connector includes a first connecting flange and a first fixing member fixed to the first connecting flange, with the first fixing member and the first connecting flange being arranged perpendicularly.

7. The flexible quadruped robot with a discrete spine according to claim 5, characterized in that: The thigh is a hollow structure, and a lower leg connector and a connecting rod are provided inside the thigh. The lower leg connector is fixed to the output shaft of the lower leg drive motor. One end of the connecting rod is hinged to the lower leg connector, and the other end is hinged to the lower leg. A first elastic energy accumulator is provided on the connecting rod.

8. The flexible quadruped robot with a discrete spine according to claim 5, characterized in that: The first elastic energy storage device includes a first elastic element, a sliding element, and a guide rail. The first elastic element is sleeved on the connecting rod, with one end fixed to the connecting rod and the other end fixed to the sliding element. The guide rail is fixed to the inner side of the first thigh shell or the second thigh shell. The sliding element is sleeved on the connecting rod and is disposed on the guide rail.

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