A multi-degree-of-freedom bionic mechanical leg combining active and passive motions

Abstract

The present invention discloses a multi-degree-of-freedom bionic mechanical leg combining active and passive components, which includes a first straight arm segment, a second straight arm segment, a third straight arm segment, a fourth straight arm segment, and a bionic foot sole; the first straight arm segment, the second straight arm segment, the third straight arm segment, the fourth straight arm segment, and the bionic foot sole are connected to form a structure with four self-rotation control activities and two controlled activities; among them, the first driving mechanism, the second driving mechanism, the third driving mechanism, and the fourth driving mechanism for active control are all structures jointly driven by a DC brushless frameless torque motor and a harmonic reducer; with this cooperation, it not only makes up for the shortcoming of low load of the servo motor, but also enables the mechanical leg to have the advantages of small volume, large reduction ratio, and large torque output, and more solves the problems of bulky joints and non-bionic appearance of traditional industrial robots.

Description

Technical Field

[0001] The invention relates to the technical field of bionic robots, and in particular to an active and passive combined multi-degree-of-freedom bionic mechanical leg. Background Art

[0002] In the field of bionic robots, the traditional driving methods of crawling robot arms mainly include hydraulic, pneumatic, and motor drives. Among them, hydraulic drive can provide high-power driving force, which is conducive to achieving high loads, but it is limited by complex pipeline design and hydraulic pump power source, and is not suitable for small robots; pneumatic can provide high-speed and high-load driving force, and is resistant to impact and vibration, but most pneumatic systems are switch control and cannot achieve precise speed, position and torque control; motor drive has the above characteristics and is widely used as a robot power source.

[0003] Traditional small robotic arms use servos as driving force. On the one hand, the driving force of the servo mechanical arm is small and cannot achieve a high load state. On the other hand, the servo cannot perform torque control and cannot achieve smooth control of the robotic arm. Brushless motors have the characteristics of high speed, high output power, small size, light weight, simple control, and easy to achieve speed, position and torque control. At present, most bionic robot dog robotic arms use brushless reduction motors plus planetary gear reducers as joint power modules to achieve bionic crawling motion. Industrial robotic arms have fast response speed and strong load capacity, but their disadvantages are large size, bloated joints, and inability to achieve bionic concealment in appearance.

[0004] First of all, from the implementation method point of view, the traditional mechanical dog-like quadruped robot has only three joint motors and three degrees of freedom on each foot, and the leg moves within one plane, which is different from the crawling method of animals such as lizards and crocodiles. At the same time, the foot end of the robot dog is usually replaced by a spherical structure, which has a simple structure but cannot achieve passive shock absorption, and ignores the structural design of the flippers, which is different from the actual appearance of reptiles.

[0005] Secondly, the size and weight of the robot arm. Usually, the design of robot dog bionic foot places the joint power module inside the body, while the industrial robot arm places the joint power module at the joint position, without considering the bionic appearance, and the size is large and the joints are bloated. Due to the limited reduction ratio of planetary gears, the planetary reducer with a large reduction ratio has a large diameter and heavy weight, and the volume of reptile legs is limited. This structure is not conducive to the design of the appearance of the robot leg.

[0006] Furthermore, the control system of the robot arm. Although the traditional industrial robot arm is small and light, it usually needs to be equipped with an external servo motor driver. The more joints it has, the more complex the motor structure is, and the more complex the drive control system required is, which is not suitable for use as a reptile-like robot leg.

[0007] In summary, the prior art has the problem of poor bionic degree in the crawling of animals such as lizards and crocodiles. Therefore, a technical solution to solve this problem is urgently needed. Summary of the Invention

[0008] The purpose of the present invention is to provide a multi-degree-of-freedom bionic mechanical leg combining active and passive movements to solve the problem of poor bionic degree in the crawling of animals such as lizards and crocodiles in the prior art.

[0009] To solve the above technical problems, the present invention provides a multi-degree-of-freedom bionic mechanical leg combining active and passive movements, including a first straight arm segment, a second straight arm segment, a third straight arm segment, a fourth straight arm segment, and a bionic foot sole; one end of the first straight arm segment is provided with a first driving mechanism for driving the first straight arm segment to rotate axially, and the other end of the first straight arm segment is rotatably connected to the second straight arm segment; a second driving mechanism is provided at the rotational connection between the second straight arm segment and the first straight arm segment for driving the second straight arm segment to swing around its rotational connection; the third straight arm segment is connected with a third driving mechanism disposed within the second straight arm segment for driving the third straight arm segment to rotate; one end of the fourth straight arm segment is rotatably connected to the third straight arm segment, and a fourth driving mechanism is provided within the fourth straight arm segment and connected to the third straight arm segment for driving the fourth straight arm segment to swing around its rotational connection; the bionic foot sole is connected to the other end of the fourth straight arm segment in a manner that it can rotate passively under force, and the bionic foot sole is a structure that can turn over passively under force; and the first driving mechanism, the second driving mechanism, the third driving mechanism, and the fourth driving mechanism are all structures jointly driven by a DC brushless frameless torque motor and a harmonic reducer.

[0010] In one embodiment, the first driving mechanism includes a first encoder driver, a first DC brushless frameless torque motor, a first harmonic reducer, and a first power output flange; the power supply end of the first encoder driver is connected to the power receiving end of the first DC brushless frameless torque motor; the power output end of the first DC brushless frameless torque motor is connected to the power input end of the first harmonic reducer; the power output end of the first harmonic reducer is connected to the first power output flange; the first power output flange is fixedly connected to the end of the first straight arm segment, and the rotation center of the first power output flange is coaxially arranged with the axial center of the first straight arm segment.

[0011] In one embodiment, the second driving mechanism includes a second encoder driver, a second DC brushless frameless torque motor, a second harmonic reducer, and a second power output flange; the power supply end of the second encoder driver is connected to the power receiving end of the second DC brushless frameless torque motor; the power output end of the second DC brushless frameless torque motor is connected to the power input end of the second harmonic reducer; the power output end of the second harmonic reducer is connected to the second power output flange; the second power output flange is fixedly connected to the end of the second straight arm segment, and the rotation center of the second power output flange is perpendicular to the axial center of the second straight arm segment.

[0012] In one embodiment, the third driving mechanism includes a third encoder driver, a third DC brushless frameless torque motor, a third harmonic reducer, and a bending-resistant flange shaft; the power supply end of the third encoder driver is connected to the power receiving end of the third DC brushless frameless torque motor; the power output end of the third DC brushless frameless torque motor is connected to the power input end of the third harmonic reducer; the power output end of the third harmonic reducer is connected to the third straight arm segment, and the rotation center of the power output end of the third harmonic reducer is coaxially arranged with the axial center of the third straight arm segment; the bending-resistant flange shaft penetrates through the third encoder driver, the third DC brushless frameless torque motor, the third harmonic reducer, and the third straight arm segment.

[0013] In one embodiment, the fourth driving mechanism is disposed within the fourth straight arm segment. The fourth driving mechanism includes an output flange shaft, a fourth encoder driver, a fourth DC brushless frameless torque motor, a fourth harmonic reducer, and an input flange shaft; the output flange shaft is fixedly connected to the end of the third straight arm segment, the axis of the output flange shaft is perpendicular to the axis of the third straight arm segment, and a conical output gear is fixedly sleeved on the output flange shaft; the power supply end of the fourth encoder driver is connected to the power receiving end of the fourth DC brushless frameless torque motor; the power output end of the fourth DC brushless frameless torque motor is connected to the power input end of the fourth harmonic reducer; the power output end of the fourth harmonic reducer is connected to the input flange shaft; a conical input gear is fixedly sleeved on the input flange shaft, and the conical input gear meshes with the conical output gear.

[0014] In one embodiment, the bionic foot sole includes a self-rotating shaft, an ankle joint, and a foot web; one end of the self-rotating shaft is rotatably connected to the end of the fourth straight arm segment, the axis of the self-rotating shaft is the same as the axis of the fourth straight arm segment, and the other end of the self-rotating shaft is fixedly connected to the ankle joint; the ankle joint is a structure that can be self-flipped under passive force; the foot web is fixedly connected to the ankle joint.

[0015] In one embodiment, mounting holes are provided in the end cap of the fourth straight arm segment; one end of the self-rotating shaft passes through the mounting holes and is placed inside the fourth straight arm segment. A flange is provided on the peripheral wall of this end of the self-rotating shaft, and a snap ring is sleeved on this end of the self-rotating shaft. The snap ring is placed between the flange and the mounting holes, and the radial dimension of the snap ring is larger than the diameter of the mounting holes.

[0016] In one embodiment, a shock-absorbing spring is sleeved outside the self-rotating shaft, and the shock-absorbing spring is compressed between the end cap of the fourth straight arm segment and the ankle joint.

[0017] In one embodiment, the ankle joint includes a first hinge joint, a second hinge joint, a rotation shaft, and a torsion spring; the first hinge joint is fixedly connected to the self-rotating shaft, the second hinge joint is fixedly connected to the flipper, and the first hinge joint is rotatably connected to the second hinge joint; the rotation shaft is the rotation shaft of the first hinge joint and the second hinge joint; the torsion spring is sleeved outside the rotation shaft, and the two force-applying parts of the torsion spring are elastically abutted against the first hinge joint and the second hinge joint respectively.

[0018] In one embodiment, the first straight arm segment, the second straight arm segment, the third straight arm segment, the fourth straight arm segment, and the bionic foot sole are all wrapped with skin.

[0019] The beneficial effects of the present invention are as follows:

[0020] Since the first drive mechanism, the second drive mechanism, the third drive mechanism, and the fourth drive mechanism are all structures jointly driven by a DC brushless frameless torque motor and a harmonic reducer, with the mutual cooperation of the DC brushless frameless torque motor and the harmonic reducer, it not only makes up for the shortcomings of the low load of the servo motor, but also enables the mechanical leg to have the advantages of small volume, large reduction ratio, and large torque output. It also solves the problems of the bloated joints and non-bionic appearance of traditional industrial robots. It makes up for the shortcomings of the few degrees of freedom of traditional bionic mechanical legs and solves the problem of the flexibility of the bionic feet of reptiles. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 is a schematic structural diagram provided by an embodiment of the present invention;

[0023] Figure 2 is Figure 1Schematic diagram of the first driving mechanism structure;

[0024] Figure 3 is Figure 1 Schematic diagram of the second driving mechanism structure;

[0025] Figure 4 is Figure 1 Schematic diagram of the second arm segment and the third straight arm segment structure;

[0026] Figure 5 is Figure 4 Schematic diagram of the disassembled structure;

[0027] Figure 6 is Figure 5 Schematic diagram of the third driving mechanism structure;

[0028] Figure 7 is Figure 4 Schematic diagram of the sectional structure;

[0029] Figure 8 is Figure 1 Schematic diagram of the fourth straight arm segment structure;

[0030] Figure 9 is Figure 8 Schematic diagram of the disassembled structure;

[0031] Figure 10 is Figure 1 Schematic diagram of the linkage structure between the third straight arm segment and the fourth straight arm segment;

[0032] Figure 11 is Figure 9 Schematic diagram of the local structure;

[0033] Figure 12 is Figure 11 Schematic diagram of the enlarged semi-sectional structure of part A;

[0034] The reference signs are as follows:

[0035] 11. First straight arm segment; 12. Second straight arm segment; 13. Third straight arm segment; 131. Side plate flange; 132. Intermediate flange; 14. Fourth straight arm segment; 141. Mounting hole;

[0036] 20. Bionic foot sole; 21. Self-rotating shaft; 211. Flange; 22. Ankle joint; 221. First hinge joint; 222. Second hinge joint; 223. Rotating shaft; 224. Torsion spring; 23. Fin; 24. Snap ring; 25. Shock-absorbing spring;

[0037] 31. First driving mechanism; 311. First coded driver; 312. First DC brushless frameless torque motor; 313. First harmonic reducer; 314. First power output flange;

[0038] 32. Second driving mechanism; 321. Second coding driver; 322. Second DC brushless frameless torque motor; 323. Second harmonic reducer; 324. Second power output flange;

[0039] 33. Third driving mechanism; 331. Third coding driver; 332. Third DC brushless frameless torque motor; 333. Third harmonic reducer; 334. Bending-resistant flange shaft;

[0040] 34. Fourth driving mechanism; 341. Output flange shaft; 342. Fourth coding driver; 343. Fourth DC brushless frameless torque motor; 344. Fourth harmonic reducer; 345. Input flange shaft; 346. Tapered output gear; 347. Tapered input gear;

[0041] 41. First rotating shaft; 42. Second rotating shaft; 43. Third rotating shaft; 44. Fourth rotating shaft. Detailed implementation mode

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0043] The present invention provides a multi-degree-of-freedom bionic mechanical leg combining active and passive movements. As shown in Figures 1 to 10 , it includes a first straight arm segment 11, a second straight arm segment 12, a third straight arm segment 13, a fourth straight arm segment 14, and a bionic foot sole 20. One end of the first straight arm segment 11 is provided with a first driving mechanism 31, and the first driving mechanism 31 is used to drive the first straight arm segment 11 to rotate axially. The other end of the first straight arm segment 11 is rotatably connected to the second straight arm segment 12. A second driving mechanism 32 is provided at the rotational connection between the second straight arm segment 12 and the first straight arm segment 11, and the second driving mechanism 32 is used to drive the second straight arm segment 12 to swing around its rotational connection. The third straight arm segment 13 is connected to a third driving mechanism 33, and the third driving mechanism 33 is arranged inside the second straight arm segment 12. The third driving mechanism 33 is used to drive the third straight arm segment 13 to rotate. One end of the fourth straight arm segment 14 is rotatably connected to the third straight arm segment 13. A fourth driving mechanism 34 is arranged inside the fourth straight arm segment 14. The fourth driving mechanism 34 is connected to the third straight arm segment 13, and the fourth driving mechanism 34 is used to drive the fourth straight arm segment 14 to swing around its rotational connection. The bionic foot sole 20 is connected to the other end of the fourth straight arm segment 14 in a manner that can rotate passively under force, and the bionic foot sole 20 is a structure that can turn over passively under force. Moreover, the first driving mechanism 31, the second driving mechanism 32, the third driving mechanism 33, and the fourth driving mechanism 34 are all structures jointly driven by a DC brushless frameless torque motor and a harmonic reducer.

[0044] Regarding the above-mentioned brushless DC frameless torque motor, it should be noted that the brushless DC frameless torque motor is a special type of permanent magnet brushless synchronous motor. Its load is directly connected to the rotor without transmission components, so the torque motor is a direct drive technology. Moreover, the brushless DC frameless torque motor has no housing, bearings or measurement system, and other components are selected by technicians according to the required applications.

[0045] Different from traditional motors, the specifications of brushless DC frameless torque motors are mainly composed of torque and speed, rather than power. Moreover, the peak torque determines the torque that the motor can actually generate, the continuous torque determines the torque that the motor can continuously provide, and the load cycle of the application determines the degree of dependence on torque or continuous torque.

[0046] The brushless DC frameless torque motor adopts the design of a constant reluctance brushless motor. The motor consists of a circular stator and a rotor. The stator does not adopt a toothed lamination design, but is composed of smooth cylindrical laminations. The rotor consists of multi-pole rare earth permanent magnet poles and a ring-shaped hollow shaft. The characteristic of this structure is to ensure a large air gap, and the magnetic reluctance is uniform throughout the working air gap. Therefore, the motor has the advantage of no cogging torque, such as:

[0047] · The harmonic content of the sinusoidal back electromotive force is low. The typical design value of the harmonic content is about 2.5% for the third harmonic and 0.3% for the fifth harmonic.

[0048] · There is no cogging torque fluctuation.

[0049] · The torque / current linear range is wide and the linearity is high.

[0050] · The torque density is high.

[0051] · The inductance and electrical time constant are small, and the dynamic response is fast.

[0052] · The requirement for the coaxiality of the stator and rotor installation is low.

[0053] The above advantages make this series of torque motors operate smoothly and noiselessly. With the cooperation of appropriate sensors and drivers, high positioning accuracy and speed servo operation can be achieved. The split-ring ultra-thin structure adopted by the motor is especially suitable for application occasions with strict requirements for space size and weight. This series of motors can meet the usage environment requirements from -50 degrees to +85 degrees.

[0054] Regarding the above-mentioned harmonic reducer, it should be noted that the harmonic reducer mainly consists of four basic components: a wave generator, a flexible gear, a flexible bearing, and a rigid gear. It is a gear drive that relies on the wave generator assembled with a flexible bearing to make the flexible gear produce controllable elastic deformation and mesh with the rigid gear to transmit motion and power. Its advantages are as follows:

[0055] · High transmission speed ratio. The speed ratio range of a single-stage harmonic gear drive is 70 - 320, and it can reach 1000 in some devices. For multi-stage drives, the speed ratio can exceed 30,000. It can be used not only for speed reduction but also for speed increase.

[0056] · High load-carrying capacity. This is because in harmonic gear drives, the number of simultaneously meshing teeth is large. In a double-wave drive, the number of simultaneously meshing teeth can reach more than 30% of the total number of teeth. Moreover, the flexspline is made of high-strength materials, and the tooth-to-tooth contact is a surface contact.

[0057] · High transmission accuracy. This is because in harmonic gear drives, the number of simultaneously meshing teeth is large, and the errors are averaged out, that is, the multi-tooth meshing compensates for the errors with each other, so the transmission accuracy is high. Under the same gear accuracy grade, the transmission error is only about 1 / 4 of that of ordinary cylindrical gear drives. At the same time, the radius of the wave generator can be slightly changed to increase the deformation of the flexspline to make the backlash very small, and even backlash-free meshing can be achieved. Therefore, the harmonic gear reducer has a small backlash in transmission and is suitable for reverse rotation.

[0058] · High transmission efficiency and smooth motion. Since the flexspline teeth make uniform radial movements during transmission, even when the input speed is very high, the relative sliding speed of the teeth is still extremely low (so it is 1% of that of ordinary involute gear drives). Therefore, the tooth wear is small and the efficiency is high (up to 69% - 96%). Also, since both sides of the gear are involved in the work during engagement and disengagement, there is no impact phenomenon and the motion is smooth.

[0059] · Simple structure, few parts, and convenient installation. There are only three basic components, and the input and output shafts are coaxial, so the structure is simple and the installation is convenient.

[0060] · Small volume and light weight. Compared with general speed reducers, when the output torque is the same, the volume of the harmonic gear reducer can be reduced by 2 / 3 and the weight can be reduced by 1 / 2.

[0061] · It can transmit motion to an enclosed space. Utilizing the flexible characteristics of the flexspline, this valuable advantage of the gear drive is incomparable to other existing drives.

[0062] Therefore, this embodiment uses a DC brushless frameless torque motor, combined with a harmonic reducer, to achieve a small volume, a large reduction ratio, and a large torque output, which not only makes up for the shortcomings of low load of the servo motor but also solves the problems of the bloated joints of traditional industrial robots and the non-bionic appearance.

[0063] When in application, the first driving mechanism 31 can control the first straight arm segment 11 to rotate around the first rotating shaft 41, the second driving mechanism 32 can control the second straight arm segment 12 to swing around the second rotating shaft 42, the third driving mechanism 33 can control the third straight arm segment 13 to rotate around the third rotating shaft 43, and the fourth driving mechanism 34 can control the fourth straight arm segment 14 to swing around the fourth rotating shaft 44. The bionic foot sole 20 can achieve passive rotation and passive flipping, that is, it also enables the multi-degree-of-freedom bionic mechanical leg to have four active degrees of freedom and two passive degrees of freedom, and the motion posture will become more realistic.

[0064] To achieve the driving function of the first driving mechanism 31, this embodiment is preferably set as Figure 2 As shown, at this time, the first driving mechanism 31 includes a first encoder driver 311, a first DC brushless frameless torque motor 312, a first harmonic reducer 313, and a first power output flange 314; the power supply end of the first encoder driver 311 is connected to the power receiving end of the first DC brushless frameless torque motor 312; the power output end of the first DC brushless frameless torque motor 312 is connected to the power input end of the first harmonic reducer 313; the power output end of the first harmonic reducer 313 is connected to the first power output flange 314; the first power output flange 314 is fixedly connected to the end of the first straight arm segment 11, and the rotation center of the first power output flange 314 is coaxially arranged with the axial center of the first straight arm segment 11.

[0065] At this time, the first encoder driver 311, the first DC brushless frameless torque motor 312, the first harmonic reducer 313, and the first power output flange 314 are all disk-shaped, so they can be sequentially connected into a cylindrical shape, which can not only reduce the occupied space of the first driving mechanism 31, but also match the shape of the cylindrical first straight arm segment 11, thus improving the bionic degree.

[0066] When the first driving mechanism 31 is working, the first encoder driver 311 is used to achieve the encoding and driving functions to control the first DC brushless frameless torque motor 312 to operate. The high-speed rotation of the first DC brushless frameless torque motor 312 will be changed into low-speed rotation by the first harmonic reducer 313, and thus drive the first power output flange 314 and the first straight arm segment 11 to achieve synchronous rotation.

[0067] To achieve the driving function of the second driving mechanism 32, this embodiment is preferably set as Figures 2 to 4As shown, at this time, the second driving mechanism 32 includes a second coding driver 321, a second DC brushless frameless torque motor 322, a second harmonic reducer 323, and a second power output flange 324; the power supply end of the second coding driver 321 is connected to the power receiving end of the second DC brushless frameless torque motor 322; the power output end of the second DC brushless frameless torque motor 322 is connected to the power input end of the second harmonic reducer 323; the power output end of the second harmonic reducer 323 is connected to the second power output flange 324; the second power output flange 324 is fixedly connected to the end of the second straight arm segment 12, and the rotation center of the second power output flange 324 is perpendicular to the axial center of the second straight arm segment 12.

[0068] At this time, the second coding driver 321, the second DC brushless frameless torque motor 322, the second harmonic reducer 323, and the second power output flange 324 are all disc-shaped, so they can be sequentially connected into a cylindrical shape, which not only reduces the occupied space of the second driving mechanism 32, but also matches the smooth joint shape, thus improving the bionic degree.

[0069] It should be noted that the second power output flange 324 is connected to the end face of the cylindrical second straight arm segment 12 by its side, and their axes are perpendicular to each other, so that when the second driving mechanism 32 operates, it can drive the second straight arm segment 12 to swing around the central axis of the second power output flange 324.

[0070] When the second driving mechanism 32 is working, the second coding driver 321 is used to realize the coding and driving functions to control the operation of the second DC brushless frameless torque motor 322. The high-speed rotation of the second DC brushless frameless torque motor 322 will be changed into low-speed rotation by the second harmonic reducer 323, and this is used to drive the second power output flange 324 and the second straight arm segment 12 to achieve synchronous motion (that is, the self-rotation of the second power output flange 324 and the swing of the second straight arm segment 12).

[0071] To realize the driving function of the third driving mechanism 33, this embodiment is preferably set as Figures 4 to 7As shown, at this time, the third driving mechanism 33 includes a third coding driver 331, a third DC brushless frameless torque motor 332, a third harmonic reducer 333, and a bending-resistant flange shaft 334; the power supply end of the third coding driver 331 is connected to the power receiving end of the third DC brushless frameless torque motor 332; the power output end of the third DC brushless frameless torque motor 332 is connected to the power input end of the third harmonic reducer 333; the power output end of the third harmonic reducer 333 is connected to the third straight arm segment 13, and the rotation center of the power output end of the third harmonic reducer 333 is coaxially arranged with the axial center of the third straight arm segment 13; the bending-resistant flange shaft 334 is inserted through the third coding driver 331, the third DC brushless frameless torque motor 332, the third harmonic reducer 333, and the third straight arm segment 13.

[0072] At this time, the third coding driver 331, the third DC brushless frameless torque motor 332, and the third harmonic reducer 333 are all disc-shaped, so they can be sequentially connected into a cylindrical shape. This not only reduces the occupied space of the third driving mechanism 33, but also facilitates storage in the cylindrical second straight arm segment 12, thereby improving the structural compactness and avoiding the problem of bloated structure.

[0073] When the third driving mechanism 33 is working, the third coding driver 331 is used to realize the coding and driving functions, so as to control the operation of the third DC brushless frameless torque motor 332. The high-speed rotation of the third DC brushless frameless torque motor 332 will be changed into low-speed rotation by the third harmonic reducer 333, and the third straight arm segment 13 is driven to rotate self.

[0074] It should be noted that at this time, since the bending-resistant flange shaft 334 is inserted through the third coding driver 331, the third DC brushless frameless torque motor 332, the third harmonic reducer 333, and the third straight arm segment 13, the bending moment of the arm segment will be transmitted to the outer shell of the arm segment, effectively increasing the load of the robotic arm, preventing the third driving mechanism 33 from being overloaded, and improving the structural stability.

[0075] In order to realize the driving function of the fourth driving mechanism 34, this embodiment is preferably set as Figures 8 to 10As shown in the figure, at this time, the fourth driving mechanism 34 is arranged inside the fourth straight arm section 14. The fourth driving mechanism 34 includes an output flange shaft 341, a fourth encoder driver 342, a fourth DC brushless frameless torque motor 343, a fourth harmonic reducer 344, and an input flange shaft 345. The output flange shaft 341 is fixedly connected to the end of the third straight arm section 13. The axial direction of the output flange shaft 341 is perpendicular to the axial direction of the third straight arm section 13, and a conical output gear 346 is fixedly inserted through the output flange shaft 341. The power supply end of the fourth encoder driver 342 is connected to the power receiving end of the fourth DC brushless frameless torque motor 343. The power output end of the fourth DC brushless frameless torque motor 343 is connected to the power input end of the fourth harmonic reducer 344. The power output end of the fourth harmonic reducer 344 is connected to the input flange shaft 345. A conical input gear 347 is fixedly inserted through the input flange shaft 345, and the conical input gear 347 meshes with the conical output gear 346.

[0076] At this time, the fourth encoder driver 342, the fourth DC brushless frameless torque motor 343, and the fourth harmonic reducer 344 are all disk-shaped, so they can be sequentially connected into a cylindrical shape. This can not only reduce the occupied space of the fourth driving mechanism 34, but also facilitate storage inside the cylindrical fourth straight arm section 14, thereby improving the structural compactness and avoiding the problem of bloated structure.

[0077] When the fourth driving mechanism 34 is working, the fourth encoder driver 342 is used to realize the encoding and driving functions to control the operation of the fourth DC brushless frameless torque motor 343. The high-speed rotation of the fourth DC brushless frameless torque motor 343 will be changed into low-speed rotation by the fourth harmonic reducer 344, and this drives the input flange shaft 345 and the conical input gear 347 to rotate synchronously. The output flange shaft 341 and the conical output gear 346 are set in a coaxial fixed connection state. When installed, both ends of the output shaft flange 341 are fixedly connected to the side plate flanges 131 of the third straight arm section 13, and bearings are installed at both ends of the output shaft flange 341 so that it can only rotate around its own axial direction. During operation, the power is transmitted from the conical input gear 347 to the conical output gear 346, and then drives the output shaft flange 341 to rotate. Since the output shaft flange is fixedly connected to the side plate flanges 131 of the third straight arm section 13, conversely, the fourth straight arm section 14 rotates around the axial direction of the output shaft flange 341, thereby realizing the swing between the fourth straight arm section 14 and the third straight arm section 13.

[0078] It should be noted that the third straight arm section 13 includes two parallel and opposite side plate flanges 131 and an intermediate flange 132 connected between the two side plate flanges 131, so that the outer shape of the third straight arm section 13 is in a U shape. At this time, the output flange shaft 341 will pass through the fourth straight arm section 14 and be fixedly connected between the two side plate flanges 131, thereby realizing the rotational connection and installation between the third straight arm section 13 and the fourth straight arm section 14.

[0079] To achieve the movement function of the bionic foot sole 20, this embodiment is preferably arranged as Figure 1 , Figure 11 and Figure 12 As shown, at this time, the bionic foot sole 20 includes a self-rotating shaft 21, an ankle joint 22 and a foot web 23; one end of the self-rotating shaft 21 is rotatably connected to the end of the fourth straight arm segment 14, the axial direction of the self-rotating shaft 21 is the same as that of the fourth straight arm segment 14, and the other end of the self-rotating shaft 21 is fixedly connected to the ankle joint 22; the ankle joint 22 is a structure that can be self-inverted under passive force; the foot web 23 is fixedly connected to the ankle joint 22.

[0080] After adopting this setting method, the bionic foot sole 20 will be able to achieve passive self-rotation and bending and flipping functions, thereby making the bionic degree of the multi-degree-of-freedom bionic mechanical leg higher.

[0081] Specifically, this embodiment sets an installation hole 141 on the end cover of the fourth straight arm segment 14, and a self-lubricating copper sleeve can be installed in the installation hole 141; one end of the self-rotating shaft 21 passes through the installation hole 141 and is placed inside the fourth straight arm segment 14. A flange 211 is provided on the peripheral wall of this end of the self-rotating shaft 21. A snap ring 24 is sleeved on this end of the self-rotating shaft 21. The snap ring 24 is placed between the flange 211 and the installation hole 141, and the radial dimension of the snap ring 24 is larger than the diameter of the installation hole 141.

[0082] Therefore, the self-rotating shaft 21 is installed in the installation hole 141 in a self-rotating and movable manner, and anti-disengagement is achieved by using the snap ring 24. At this time, if the bionic foot sole 20 is subjected to an external force impact, it will rotate by itself without the need for manual active force application, thereby making the structure of the multi-degree-of-freedom bionic mechanical leg more concise.

[0083] Moreover, at this time, a shock-absorbing spring 25 is sleeved outside the self-rotating shaft 21. The self-rotating shaft 21 can axially slide along the installation hole 141. Limited by the snap ring 24 and the boss, the shock-absorbing spring 25 is compressed between the end cover of the fourth straight arm segment 14 and the ankle joint 22, which also enables the bionic foot sole 20 to have a shock-absorbing function.

[0084] In addition, this embodiment also sets the ankle joint 22 to include a first hinge joint 221, a second hinge joint 222, a turning shaft 223 and a torsion spring 224; the first hinge joint 221 is fixedly connected to the self-rotating shaft 21, the second hinge joint 222 is fixedly connected to the foot web 23, and the first hinge joint 221 is rotatably connected to the second hinge joint 222; the turning shaft 223 is the rotation axis of the first hinge joint 221 and the second hinge joint 222; the torsion spring 224 is sleeved outside the turning shaft 223, and the two force-applying parts of the torsion spring 224 are elastically abutted against the first hinge joint 221 and the second hinge joint 222 respectively.

[0085] At this time, both the first hinge joint 221 and the second hinge joint 222 are substantially in a U shape, facilitating the installation of the rotation shaft 223 and the torsion spring 224 in the hinge space between the two. After adopting this structure, if the bionic foot sole 20 is not subjected to an external force, the torsion spring 224 can make the bionic foot sole 20 in an extended state. If the bionic foot sole 20 contacts the ground, the bionic foot sole 20 will automatically flip to a matching angle, making the flipping posture of the bionic foot sole 20 more realistic.

[0086] Furthermore, in this embodiment, a skin (not shown) can be wrapped around the first straight arm segment 11, the second straight arm segment 12, the third straight arm segment 13, the fourth straight arm segment 14, and the bionic foot sole 20, making the multi-degree-of-freedom bionic mechanical leg more realistic in terms of posture and appearance.

[0087] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A multi - degree - of - freedom bionic mechanical leg combining active and passive movements, characterized in that it includes a first straight - arm segment, a second straight - arm segment, a third straight - arm segment, a fourth straight - arm segment and a bionic foot sole; One end of the first straight - arm segment is provided with a first driving mechanism, which is used to drive the first straight - arm segment to rotate axially, and the other end of the first straight - arm segment is rotatably connected to the second straight - arm segment; A second driving mechanism is provided at the rotational connection between the second straight - arm segment and the first straight - arm segment, and the second driving mechanism is used to drive the second straight - arm segment to swing around its rotational connection; The third straight - arm segment is connected with a third driving mechanism, and the third driving mechanism is arranged inside the second straight - arm segment. The third driving mechanism is used to drive the third straight - arm segment to rotate; One end of the fourth straight - arm segment is rotatably connected to the third straight - arm segment. A fourth driving mechanism is arranged inside the fourth straight - arm segment. The fourth driving mechanism is connected to the third straight - arm segment, and the fourth driving mechanism is used to drive the fourth straight - arm segment to swing around its rotational connection; The bionic foot sole is connected to the other end of the fourth straight - arm segment in a way that it can rotate passively under force, and the bionic foot sole is a structure that can turn over passively under force; And the first driving mechanism, the second driving mechanism, the third driving mechanism and the fourth driving mechanism are all structures jointly driven by a direct - current brushless frameless torque motor and a harmonic reducer.

2. The multi - degree - of - freedom bionic mechanical leg according to claim 1, characterized in that The first driving mechanism includes a first encoder driver, a first direct - current brushless frameless torque motor, a first harmonic reducer and a first power output flange; The power supply end of the first encoder driver is connected to the energy receiving end of the first direct - current brushless frameless torque motor; The power output end of the first direct - current brushless frameless torque motor is connected to the power input end of the first harmonic reducer; The power output end of the first harmonic reducer is connected to the first power output flange; The first power output flange is fixedly connected to the end of the first straight - arm segment, and the rotation center of the first power output flange is coaxially arranged with the axial center of the first straight - arm segment.

3. The multi - degree - of - freedom bionic mechanical leg according to claim 1, characterized in that The second driving mechanism includes a second encoder driver, a second direct - current brushless frameless torque motor, a second harmonic reducer and a second power output flange; The power supply end of the second encoder driver is connected to the energy receiving end of the second direct - current brushless frameless torque motor; The power output end of the second direct - current brushless frameless torque motor is connected to the power input end of the second harmonic reducer; The power output end of the second harmonic reducer is connected to the second power output flange; The second power output flange is fixedly connected to the end of the second straight - arm segment, and the rotation center of the second power output flange is perpendicular to the axial center of the second straight - arm segment.

4. The multi - degree - of - freedom bionic mechanical leg according to claim 1, characterized in that The third driving mechanism includes a third encoder driver, a third direct - current brushless frameless torque motor, a third harmonic reducer and a bending - resistant flange shaft; The energy supply end of the third coding driver is connected to the energy receiving end of the third DC brushless frameless torque motor; The power output end of the third DC brushless frameless torque motor is connected to the power input end of the third harmonic reducer; The power output end of the third harmonic reducer is connected to the third straight arm segment, and the rotation center of the power output end of the third harmonic reducer is coaxially arranged with the axial center of the third straight arm segment; The bending-resistant flange shaft penetrates through the third coding driver, the third DC brushless frameless torque motor, the third harmonic reducer, and the third straight arm segment.

5. The multi-degree-of-freedom bionic mechanical leg according to claim 1, characterized in that The fourth driving mechanism is arranged in the fourth straight arm segment, and the fourth driving mechanism includes an output flange shaft, a fourth coding driver, a fourth DC brushless frameless torque motor, a fourth harmonic reducer, and an input flange shaft; The output flange shaft is fixedly connected to the end of the third straight arm segment, the axis of the output flange shaft is perpendicular to the axis of the third straight arm segment, and a conical output gear is fixedly sleeved on the output flange shaft; The energy supply end of the fourth coding driver is connected to the energy receiving end of the fourth DC brushless frameless torque motor; The power output end of the fourth DC brushless frameless torque motor is connected to the power input end of the fourth harmonic reducer; The power output end of the fourth harmonic reducer is connected to the input flange shaft; A conical input gear is fixedly sleeved on the input flange shaft, and the conical input gear meshes with the conical output gear.

6. The multi-degree-of-freedom bionic mechanical leg according to claim 1, characterized in that The bionic foot sole includes a self-rotating shaft, an ankle joint, and a foot web; One end of the self-rotating shaft is rotatably connected to the end of the fourth straight arm segment, the axis of the self-rotating shaft is the same as the axis of the fourth straight arm segment, and the other end of the self-rotating shaft is fixedly connected to the ankle joint; The ankle joint is a structure that can be self-flipped under passive force; The foot web is fixedly connected to the ankle joint.

7. The multi-degree-of-freedom bionic mechanical leg according to claim 6, characterized in that An installation hole is provided on the end cover of the fourth straight arm segment; One end of the self-rotating shaft passes through the installation hole and is placed inside the fourth straight arm segment. A flange is provided on the peripheral wall of this end of the self-rotating shaft, and a snap ring is sleeved on this end of the self-rotating shaft. The snap ring is placed between the flange and the installation hole, and the radial dimension of the snap ring is larger than the diameter of the installation hole.

8. The multi-degree-of-freedom bionic mechanical leg according to claim 7, characterized in that, A shock-absorbing spring is sleeved on the self-rotating shaft, and the shock-absorbing spring is compressed between the end cover of the fourth straight arm segment and the ankle joint.

9. The multi-degree-of-freedom bionic mechanical leg according to claim 6, characterized in that The ankle joint includes a first hinge joint, a second hinge joint, a flipping shaft, and a torsion spring; The first hinge joint is fixedly connected to the self-rotating shaft, the second hinge joint is fixedly connected to the foot web, and the first hinge joint is rotatably connected to the second hinge joint; The flipping shaft is the rotation shaft of the first hinge joint and the second hinge joint; The torsion spring is sleeved outside the turning shaft, and two force-applying portions of the torsion spring are elastically abutted against the first hinge joint and the second hinge joint respectively.

10. The multi-degree-of-freedom bionic mechanical leg according to any one of claims 1 to 9, characterized in that, The first straight arm segment, the second straight arm segment, the third straight arm segment, the fourth straight arm segment and the bionic foot sole are all wrapped with skins.

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