CN114771688A - Cable-free three-degree-of-freedom joint module and bionic leg and foot structure - Google Patents

Abstract

The invention relates to a cableless three-degree-of-freedom joint module and a bionic leg and foot structure. The cableless three-degree-of-freedom joint realizes the built-in structural form of a knee joint cable, the power and signal cables of a knee joint module realize protection and wiring through a forward swing joint hollow shaft connected with the knee joint module in series, the problems of interference and reliability caused by the fact that the knee joint cable is externally arranged when the bionic robot moves are solved, and after the bionic robot is integrated, the system is free of the externally arranged cable, and the reliability and safety of the system can be greatly improved. The modularized single-leg module of the bionic robot is modularized, high in reliability and convenient to install and detach. The leg-foot and cable-free bionic joint of the bionic robot has high modularization degree and good reliability and stability, and can be widely applied to bionic robots with double feet, four feet, six feet, wheel feet and the like.

Description

A cableless three-degree-of-freedom joint module and bionic leg-foot structure

technical field

The invention belongs to the field of bionic robots, and particularly relates to a cableless three-degree-of-freedom joint module and a bionic leg-foot structure, which are used for bionic robots such as biped and quadruped robots.

Background technique

Legged robot research is increasingly pursuing high-speed and high-dynamic maneuverability under higher load capacity. However, this poses more stringent challenges to the design of robot action and drive systems. Under realistic size and weight constraints, Designing joint actuators that meet the requirements of high dynamic performance has become the pursuit of many robot designers, and has even become a rigid condition that limits and constrains the robot's capability boundary. The flexibility and reliability of the robot's motion posture are particularly prominent and important. The degree of freedom configuration of the robot's joints and the wiring method directly affect the flexibility and reliability of the robot. Therefore, it is urgent to solve the degree of freedom arrangement of the multi-degree-of-freedom joints, the wiring of the cable harness and the highly dynamic bionic legs of the bionic robot. structural design issues.

SUMMARY OF THE INVENTION

The present invention provides a cable-free three-degree-of-freedom joint module and a bionic leg-foot structure, and the technical problems to be solved are: (1) The three-degree-of-freedom joint knee motor cable of a bionic robot is externally placed, resulting in fatigue caused by long-term reciprocating motion To avoid the problems of reliability reduction such as cable breakage and poor contact, while ensuring the modularity of the system, the motion range of the robot's multi-degree-of-freedom joints and system reliability are improved. (2) Realize the ability of plantar perception.

In order to solve the above technical problems, the present invention provides a cableless three-degree-of-freedom joint module, which is characterized in that it includes a front swing joint, a knee joint, and a lateral joint; the tail of the knee joint is fixedly connected with the output end of the front swing joint, and the front The front swing joint motor of the swing joint is fixedly connected to the output end of the side extension motor through one side of the front swing motor support seat, and the other side is connected to the robot body through a rotating pin shaft. The knee joint and the front swing joint are arranged in the same direction, and the side extension joint is arranged in the same direction. The rotation axis is perpendicular to the axis of the front swing joint and the knee joint, the front swing joint is a hollow structure, and the power line and the control line of the knee joint module are led out from the tail of the front swing motor through the hollow shaft of the front swing motor.

The tail of the knee joint is connected to the output end of the front swing motor through the knee joint mounting flange. The knee joint mounting flange is located on the crossed roller bearing. The outer ring of the crossed roller bearing is installed in cooperation with the knee joint mounting flange. The ring is installed in cooperation with the support bracket of the front swing motor.

The knee joint mounting flange 104 is designed with a front swing joint output profile 1043 to form a profile fit with the front rocker joint output shaft, and the inner ring of the crossed roller bearing fits with the front rocker joint support seat boss surface 10213.

The knee joint cable is led out from the tail of the front swing joint through the cable groove 1044 on the knee joint installation flange 104 and then through the front swing joint hollow shaft 1022, and a cable support bearing 1023 is designed at the front swing joint hollow shaft.

A single joint is composed of an axial flux motor equipped with an integrated reducer, and the double stator windings of the axial flux motor are fixed on the structural parts of the motor.

A cableless three-degree-of-freedom joint module according to claim 5, characterized in that, part of the structure of the reducer is embedded in the inner diameter space of the axial flux motor, and the output end bearing of the joint motor adopts a crossed roller bearing.

The modular installation structure is adopted, and the entire installation interface is located on the installation end face of the side extension motor and the support end face of the front swing motor.

A leg-foot structure of a bionic robot, which is characterized in that it includes a foot thigh, a foot calf and a cable-free three-degree-of-freedom joint module, the foot thigh and the knee joint motor shell are fixedly installed, and the foot calf 3 and the foot thigh 2 are connected by a knee joint pin shaft 202 is connected to form a rotating pair, one end of the crank 11 is fixedly connected to the output shaft of the knee joint, and the other end is connected to the lower leg 3 through the connecting rod 12 to form a parallel four-bar linkage mechanism.

The lower end of the lower leg of the foot is fixedly connected with the flange connection plate, a force sensor is installed in the hole of the flange connection plate, and the bolt passes through the force sensor to connect the flange connection plate and the sole connection seat; the lower end of the flange connection plate 4 has a hexagonal convex shape. The platform 403 is slidably matched with the hexagonal cavity 601 on the sole connecting base 6, so that the robot can float along the direction of the legs when walking.

The upper part of the flange connection plate 4 is provided with a bolt hole 401 for connecting with the calf 3 of the foot; the upper end is provided with an O-ring groove and a cavity for installing the force sensor, and the O-ring 8 is installed in the O-ring groove 402, The force sensor 5 is installed in a cavity 404, and a hole for wiring is opened in the cavity.

Beneficial effects:

(1) While ensuring the modularity, it solves the reliability reduction problems such as cable breakage and poor contact caused by the long-term reciprocating fatigue of the traditional bionic robot multi-degree-of-freedom joints, especially the knee joint cables.

(2) High reliability, good modularity, easy disassembly and maintenance.

(3) Design a bionic leg-foot structure that can meet the requirements of walking in the field and have the ability to sense the ground. In the sequence of bionic robots such as hexapods and wheel feet.

Description of drawings

FIG. 1 is a cross-sectional view of a cableless three-degree-of-freedom joint of the present invention.

FIG. 2 is a schematic diagram of a three-degree-of-freedom motion rotating shaft of the present invention.

Figure 3 is a three-dimensional structural diagram of a knee joint mounting flange.

FIG. 4 is a three-dimensional structural view of a lateral extension joint support seat.

Figures 5(a) and (b) are sectional views of the three-dimensional structure and the internal structure of the leg-foot system of the present invention, respectively.

Figures 6(a)-(e) are respectively the structure diagram of the foot-ground sensing according to the present invention and the perspective view of each component thereof.

7 is a perspective view of the structure of the bionic leg and foot system of the present invention.

FIG. 8 is an integrated three-dimensional structural view of the bionic leg and foot machine of the present invention.

9 is a perspective view of a bionic leg and foot using a cableless three-degree-of-freedom joint according to the present invention.

Description of marks in the figure:

1-Three degrees of freedom joint, 101-Side joint, 1011-Side joint mounting flange, 102-Front swing joint, 1021-Front swing joint support seat, 10211-Support seat fixing square hole, 10212 Support seat fixing shaft hole , 10213-Front swing joint support seat boss, 1022-Front swing joint hollow shaft, 1023-Cable support bearing, 1024-Front swing joint reducer, 1025-Front swing joint motor, 103-Knee joint, 1031-Knee joint Output shaft, 1032-knee joint reducer, 1033-knee joint motor, 104-knee joint mounting flange, 1041-knee joint fixing hole, 1042-front swing motor fixing hole, 1043-front swing joint output profile, 1044-knee Joint wiring groove, 105-knee joint mounting flange support bearing, 106-front swing joint support seat mounting bearing, 2-foot thigh, 201-crank bearing seat, 202-knee joint pin, 203-knee joint lock nut , 204-knee joint thrust bearing, 205-knee joint copper sleeve, 206-knee joint steel sleeve, 3-foot calf, 301- connecting rod pin, 302- connecting rod elastic retaining ring, 303- connecting rod copper sleeve, 304 -Steel sleeve of connecting rod pin, 4-flange connection plate, 401-fastening screw hole, 402-O-ring installation groove, 403-hexagonal boss, 404-for installing pressure sensor cavity, 5-force Sensor, 501-Through Hole, 6- Foot Connector, 601- Hexagonal Recess, 602- Bolt Through Hole, 603- Fastening Screw Hole, 603- Hexagonal Recess, 7-Bolt, 8-O Ring, 9-protective cover, 10-foot end, 1001-fastening screw hole.

Detailed ways

In order to make the purpose, content and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below.

A cable-free three-degree-of-freedom joint module proposed by the present invention includes a lateral expansion joint 101, a front swing joint 102, a knee joint 103, and a knee joint installation flange 104;

The knee joint and the front swing joint are arranged in the same direction, the rotation axis of the lateral joint 101 is perpendicular to the axis of the front swing knee joint, the front swing joint is a hollow structure, and the power line and control line of the knee joint module pass through the front swing motor hollow shaft. lead out, so as to realize the cable-free design of the knee joint module.

The tail end of the knee joint is fixedly connected to the output end of the front swing joint, the front swing joint motor is fixedly connected to the output end of the side extension motor through one side of the front swing motor support seat, and the other side can be connected to the robot body by rotating the pin, so that the three The DOF joint module forms a simply supported beam structure.

Preferably, the lateral extension joint 101, the front swing joint 102, the knee joint 103, and the knee joint mounting flange 104 form a three-degree-of-freedom joint of the leg-foot system, the knee joint 103 and the front swing joint 102 are arranged in the same direction, and the tail of the knee joint 103 and The fixing hole 1041 of the knee joint installation flange 104 is fixedly connected, and the knee joint installation flange 104 is fixedly connected to the output shaft of the front swing joint 102 through the fixing hole 1042. In order to avoid shear stress on the fixing screw or pin, the knee joint installation flange The front swing joint output profile 1043 is designed on the 104 to form a profile fit with the front swing joint output shaft. At the same time, the knee joint mounting flange is matched with the outer ring of the crossed roller bearing 105, and the inner ring of the crossed roller bearing and the front swing joint support seat. The boss surface 10213 is matched to ensure the output stiffness and rotation accuracy of the knee joint cantilever structure. The knee joint cable passes through the wire slot 1044 and then passes through the front swing joint hollow shaft 1022 and is led out from the tail of the front swing joint. In order to reduce the wear of the cable fixed position caused by the knee joint cable rotating with the knee joint as a whole, the hollow shaft is designed with a The cable support bearing 1023 can ensure the free rotation of the cable. The rotation axis of the lateral joint 101 and the front swing joint 102 are arranged orthogonally, and the output shaft of the lateral joint 101 is fixedly connected with the support seat fixing square hole 10211 of the front swing joint support seat. So far, a three-degree-of-freedom joint is formed, and the knee joint cable is built in by The tail outlet of the front swing joint forms a design without flying wires.

A single joint consists of an axial flux motor equipped with an integrated reducer; the double stator windings of the axial flux motor are fixed on the structural parts of the motor, and at the same time provide installation and fixation and heat conduction and heat dissipation paths for the motor. In order to shorten the axial dimension of the joint module, part of the structure of the reducer is embedded in the inner diameter space of the axial flux motor, and the output bearing of the joint motor adopts the crossed roller bearing to realize the axial and radial loads of the cantilever structure.

A bionic robot leg-foot structure, comprising three-degree-of-freedom joints, a foot thigh 2, a foot calf 3, a flange connection plate 4, a force sensor 5, a sole connection seat 6, a bolt 7, an O-ring 8, a protective cover 9, Foot end 10. In cooperation with the above-mentioned three-degree-of-freedom joints, the foot thigh 2 is fixedly connected with the outer shell of the knee joint 103, the foot calf 3 and the foot thigh 2 are connected by the knee joint pin shaft 202 to form a rotating pair, and the knee joint copper sleeve is installed on the knee joint pin shaft 202 and the foot. In the gap formed by the calf 3, the self-lubricating performance of the copper sleeve can ensure the normal rotation of the calf of the foot. The knee joint steel sleeve 206 is installed in the gap formed by the knee joint pin 202 and the foot thigh 2, and the locking nut 203 is used to fix the knee joint pin. 202, needle roller bearings 204 are symmetrically arranged between the thigh 2 and the thigh 3 to ensure the axial rigidity and rotation accuracy of the lower leg and avoid friction, noise and other problems between the thigh 2 and the lower leg 3. One end of the crank 11 is fixedly connected with the output shaft of the knee joint, and the other end forms a rotating pair with the connecting rod 12, thereby forming a parallel four-bar linkage mechanism. 303 is installed in the gap between the connecting rod pin 301 and the connecting rod 12 to ensure the self-lubricating rotation between the connecting rod and the pin. Wear resistance, the axial movement of the connecting rod pin 301 is limited by the elastic retaining rings 302 symmetrically arranged at both ends.

Further, bolt holes 401 are opened on the flange connection plate 4 for connecting with the lower leg 3 of the foot. The O-ring 8 is installed in the groove 402, and the O-ring can provide corresponding friction force and can provide auxiliary assistance during assembly. The force sensor 5 is installed in a cavity 404, and a hole for wiring is opened in the cavity. The hexagonal boss 403 at the lower end of the flange connecting plate 4 is slidingly matched with the hexagonal concave cavity 601 on the sole connecting base 6 to ensure that the quadruped robot can float in the direction of the legs while walking, and can prevent the feet from rotating. The middle of the force sensor 5 is a through hole 501 through which the bolt can be fastened. The sole connection seat 6 is fastened together with the flange connection plate 4 and the force sensor 5 by bolts 7 . The hexagonal concave cavity 601 on the sole connecting seat 6 is slidingly matched with the hexagonal boss 403 of the flange connecting plate 4, and there is a certain floating gap between them. When the rubber sole 10 is in contact, the force is transmitted to the foot. When the base connecting seat 6 floats upward, the foot connecting seat 6 directly transmits the force to the force sensor 5, which can not only detect the landing state of the foot, but also read the force on the foot, in order to control the motion of the quadruped robot. Gestures help. The bolts fix the foot base, the flange connection and the force sensor together.

Further, the bolts 7 will fix the sole connecting seat 6, the flange connecting plate 4 and the force sensor 5 together. The O-ring 8 is installed in the groove 402, and the protective cover 9 adopts a symmetrical design and is fixed at the ankle joint of the calf 3 by bolts to complete the smooth transition from the calf to the end of the foot, thereby avoiding the steps and branches in the field of excitement. The stumbling caused by etc. will affect the movement of the robot. The foot end 10 is made of a flexible material. The inner concave structure and the outer convex structure of the sole connecting seat 6 are completely attached, and are fixed on the sole connecting seat 6 by the fastening screw holes 1001 .

Further, for the bionic leg and foot structure formed above, the form of modular assembly can be adopted. The installation bearing 106 of the pendulum joint support seat forms a simply supported beam structure of the leg and foot, so that the installation and fixation of the leg and foot system can be realized.

The power lines and signal lines of the side extension, front swing, and knee joint motors need to be drawn out for motor control. Since the output of the knee joint rotates, it must also rotate with the output shaft of the front swing joint. Rotation and rotation lead to fatigue and other problems. The signal line and power line of the knee joint motor are drawn from the tail of the knee joint. The mounting flange of the knee joint motor and the front swing joint are designed as hollow structures, and the cables are led out from the tail of the front swing joint motor through the hollow shaft. , The cable support bearing structure is designed at the position at the tail of the front swing motor to avoid the friction between the cable rotation and the casing, which will cause the cable to break and fail.

The bionic leg-foot structure realizes three-degree-of-freedom motion, the crank, the connecting rod, the calf and the thigh form a parallel four-link mechanism, and the motion of the knee joint is transformed into the flexion and extension motion of the calf through the four-link.

The flange connection plate in the middle of the bionic leg and foot is fixed on the lower leg of the foot by screws, and the upper end is provided with a groove for installing an O-ring and a cavity for installing a force sensor. There are through holes in the middle for bolt tightening. The hexagonal boss structure at the lower end is slidably matched with the hexagonal concave cavity structure on the foot bottom connecting seat to ensure that the quadruped robot can float along the direction of the legs when walking, and can prevent the feet from rotating.

The rubber sole is made of rubber material, which has a cushioning effect on the sole of the foot.

The cable-free three-degree-of-freedom joint of the present invention realizes the built-in structure of the knee joint cable, and the power and signal cables of the knee joint module are protected and wired through the front swing joint hollow shaft connected in series with it, which reduces the need for the bionic robot to avoid the The interference and reliability problems caused by the external cables of the knee joints, after the whole machine is integrated, there are no external cables, which can greatly improve the reliability and safety of the system. The bionic leg-foot structure integrates a cableless joint module and a foot-ground sensing unit, thereby realizing a modular single-leg module of a bionic robot that is modular, highly reliable, and easy to install and disassemble. The legs and feet of the bionic robot and the cableless bionic joints have a high degree of modularity, and have good reliability and stability, which solves the problem of cable wiring and routing of the current multi-degree-of-freedom bionic robot. It can be widely used in bionic robots such as bipeds, quadrupeds, hexapods and wheel feet.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principle of the present invention, several improvements and modifications can also be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (10)

1. A cable-free three-degree-of-freedom joint module, characterized in that it includes a front swing joint, a knee joint, and a lateral joint; One side of the front swing motor support base is fixedly connected to the output end of the side extension motor, and the other side is connected to the robot body through a rotating pin. The axis of the joint is vertical, the front swing joint is a hollow structure, and the power line and control line of the knee joint module are led out from the tail of the front swing motor through the hollow shaft of the front swing motor. 2. A cableless three-degree-of-freedom joint module according to claim 1, wherein the knee joint tail is connected to the output end of the front swing motor through a knee joint mounting flange, and the knee joint mounting flange is located on the cross roller. On the sub-bearing, the outer ring of the crossed roller bearing is installed in cooperation with the knee joint mounting flange, and the inner ring of the crossed roller bearing is installed in cooperation with the support bracket of the front swing motor. 3. A cableless three-degree-of-freedom joint module according to claim 2, wherein the knee joint mounting flange 104 is designed with a front swing joint output profile 1043 to form a profile fit with the front swing joint output shaft , the inner ring of the crossed roller bearing is matched with the boss surface 10213 of the front swing joint support seat. 4 . The cableless three-degree-of-freedom joint module according to claim 2 , wherein the knee joint cable passes through the front swing joint hollow shaft 1022 after passing through the cable routing slot 1044 on the knee joint installation flange 104 . Leaded out from the tail of the front swing joint, a cable support bearing 1023 is designed at the hollow shaft of the front swing joint. 5. A cableless three-degree-of-freedom joint module according to claim 1, wherein a single joint is composed of an axial flux motor with an integrated reducer, and the double stator windings of the axial flux motor are fixed on the on the structural parts of the motor. 6. A cableless three-degree-of-freedom joint module according to claim 5, characterized in that part of the structure of the reducer is embedded in the inner diameter space of the axial flux motor, and the output end bearing of the joint motor adopts crossed rollers bearing. 7 . The cableless three-degree-of-freedom joint module according to claim 1 , wherein a modular installation structure is adopted, and the entire installation interface is on the side-spreading motor installation end face and the front-swing motor support end face. 8 . 8. A bionic robot leg-foot structure, characterized in that it comprises a foot thigh, a foot calf and the cableless three-degree-of-freedom joint module according to any one of claims 1-7, and the foot thigh and the knee joint motor casing are fixed After installation, the lower leg 3 and the upper leg 2 are connected by the knee joint pin shaft 202 to form a rotating pair, one end of the crank 11 is fixedly connected with the output shaft of the knee joint, and the other end is connected with the lower leg 3 through the connecting rod 12 to form a parallel four-bar linkage mechanism. 9. The leg-foot structure of a bionic robot according to claim 8, wherein the lower end of the lower leg of the foot is fixedly connected with the flange connection plate, a force sensor is installed in the cavity of the flange connection plate, and the bolt passes through the force sensor to The flange connection plate is connected with the sole connection seat; the hexagonal boss 403 at the lower end of the flange connection plate 4 is slidably matched with the hexagonal cavity 601 on the sole connection seat 6, so that the robot can float along the leg direction when walking. 10. The leg-foot structure of a bionic robot according to claim 9, wherein the upper part of the flange connecting plate 4 is provided with a bolt hole 401 for connecting with the foot calf 3; In the cavity for installing the force sensor, the O-ring 8 is installed in the O-ring groove 402 , the force sensor 5 is installed in the cavity 404 , and holes for wiring are opened in the cavity.

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