Parallel straight-knee biped robot driven by artificial muscles

Abstract

The invention discloses a parallel straight-knee biped robot driven by artificial muscles, and relates to the technical field of bionic biped robots. The problems that an existing biped robot is bloated in structure, large in weight and insufficient in driving force are solved. The robot comprises a hip part (1) driven by a rotational joint motor, a leg part (2) driven by artificial muscles and a foot part (3). And the two rotational joint motors are respectively connected with one leg and the hip. Each leg is composed of two four-branch-chain 2R1T three-degree-of-freedom parallel mechanisms sharing the static platform, each 2R1T parallel mechanism is driven by four artificial muscles, and each leg is totally provided with eight artificial muscles serving as driving elements. The two 2R1T parallel mechanism movable platforms are connected with the hip and the feet of the robot respectively. The robot foot is a large rigid flat plate and is used for stabilizing the robot. The size is small, the weight is light, and the robot motion inertia is reduced. The method is used for occasions of man-machine interaction or collaborative operation with human beings.

Description

Technical Field

[0001] The present invention relates to the technical field of bionic biped robots, and particularly to a parallel straight-knee biped robot driven by artificial muscles. Background Art

[0002] Legged robots can achieve the ability to walk on most complex terrains by imitating the leg structures of organisms in nature. Compared with traditional wheeled or tracked robots, they have better adaptability and passability, and can complete more complex operation tasks in complex environments. Classified by the number of legs, legged robots are divided into biped robots, hexapod robots, etc. Compared with other types of robots, humanoid biped robots have the following characteristics and advantages: 1. Humanoid biped robots have better adaptability to complex environments, with smaller movement blind spots, stronger obstacle avoidance capabilities, and can achieve more flexible and diverse movements, and can be directly applied to the living and working environments of humans; 2. While retaining the basic movement capabilities of the lower limbs, humanoid biped robots can use the upper limbs to operate tools and complete corresponding operations; 3. Humanoid biped robots are similar in appearance to humans, are easily accepted psychologically by people, and are more suitable for occasions of human-computer interaction or cooperation with humans. Generally speaking, humanoid biped robots not only have the dexterous operation capabilities of traditional industrial robots, but also have better movement capabilities and higher intelligent levels, with huge market potential, and can be widely applied to many fields such as entertainment, education, personal and household services, medical care, special operations, etc.

[0003] The mechanical legs of traditional biped robots are relatively simple in mechanical structure, and most of them are in a series structure form, with drive motors installed at each joint of the legs. Just because of this, most current scholars study the drive control and bionic intelligence of mechanical legs to enable the robot to achieve flexible gaits.

[0004] For biped robots, the series multi-joint mechanical legs have insurmountable disadvantages in structure: the drive motors at each joint result in low speed and load-bearing capacity of the mechanical legs, and only by selecting motors and reducers with small mass, small volume, and large torque can the performance be improved, but this leads to a sharp increase in cost.

[0005] Existing mechanical legs that adopt artificial muscle drive (for example, the invention patent with the publication number CN105172931A and the patent name of a biped robot based on pneumatic artificial muscles) or underactuated methods such as cable drive usually adopt a relatively simple antagonistic control method, where a pair of traction cables control one joint. Such a robot drive design does not fully utilize the drive characteristics of the cable-driven robot, wastes the performance of the drive components, and makes the structure bloated and the driving force insufficient. In terms of the mechanism form, almost all existing biped mechanical legs try to imitate the shape, function, and gait of human legs as much as possible. However, due to the fundamental differences in the drive methods and structural compositions between biped robots and organisms, the shape and movement mode of humans in nature may not necessarily be the optimal solution for the structural scheme of biped robots.

[0006] In summary, there are problems with the existing biped robots, such as bloated structure, large weight, and insufficient driving force. Summary of the Invention

[0007] The purpose of the present invention is to solve the problems of the existing biped robots, such as bloated structure, large weight, and insufficient driving force.

[0008] The technical solution of the present invention is as follows:

[0009] An artificial muscle-driven parallel straight-knee biped robot includes a hip, two legs, and feet. The legs are artificial muscle-driven legs. The hip is installed on the upper parts of the two legs and drives one leg to rotate respectively. A foot is installed at the lower end of each leg; each leg includes an upper static platform, a lower static platform, a lower end moving platform, an upper end moving platform, eight artificial muscle driving components, and two three-degree-of-freedom parallel mechanisms. The upper static platform and the lower static platform are arranged parallel to each other up and down. The two three-degree-of-freedom parallel mechanisms are respectively installed on the upper part of the upper static platform and the lower part of the lower static platform. The lower end moving platform is located below the three-degree-of-freedom parallel mechanism on the side close to the foot and is connected to the foot. The upper end moving platform is installed on the upper part of the three-degree-of-freedom parallel mechanism on the side close to the hip and is connected to the hip; every four artificial muscle driving components are grouped together and connected to a three-degree-of-freedom parallel mechanism. Under the drive of the four artificial muscle driving components and the coordinated action of the lower end moving platform and the upper end moving platform, the pitching and yawing movements of the entire leg are realized.

[0010] Furthermore, the hip includes two rotary joint motors and a hip connecting member. The hip connecting member is a long strip-shaped connecting member. The two rotary joint motors are symmetrically installed on the hip connecting member, and the output shaft of each rotary joint motor passes through the hip connecting member and is respectively connected to the upper end of one leg.

[0011] Furthermore, the three-degree-of-freedom parallel mechanism includes an extension rod connecting member and extension rods. One extension rod connecting member is installed at each of the four end parts on the lower end moving platform or the upper end moving platform. One extension rod is inserted into each extension rod connecting member. Among the four extension rods, two groups of extension rods arranged oppositely are respectively the extension rod and the retraction rod. Both the extension rod and the retraction rod pass through the upper static platform or the lower static platform and then extend to the other side and are connected to four artificial muscle driving members.

[0012] Furthermore, the structures of the lower end moving platform and the upper end moving platform are the same. The lower end moving platform includes an end passive rotating joint, a Hooke's joint, a first moving platform, and a second moving platform. The first moving platform is rotationally installed on the second moving platform through the end passive rotating joint. One Hooke's joint is installed at each of the two ends of the first moving platform and the second moving platform, and the Hooke's joint rotates along the normal direction of the corresponding first moving platform and second moving platform. The extension rod connecting member is installed on the Hooke's joint, and the Hooke's joint has two degrees of rotational freedom.

[0013] Furthermore, the lower end moving platform further includes a short connecting rod. One end of the short connecting rod is rotationally connected to the Hooke's joint, and the other end of the short connecting rod is rotationally connected to the lower part of the extension rod connecting member.

[0014] Furthermore, the three-degree-of-freedom parallel mechanism further includes two limiting rings and a plurality of linear bearings. Linear bearings are sleeved on the extension rods located on the upper static platform or the lower static platform and the extension rods located on the limiting rings.

[0015] Furthermore, each group of artificial muscle driving members includes two first artificial muscles and two second artificial muscles. One end of the first artificial muscle is connected to the upper static platform or the lower static platform, and the other end of the first artificial muscle is parallel to the extension rod and is connected to the end of the extension rod located on the upper static platform or the lower static platform near the other side through a connecting block to realize the extension drive of the extension rod. One end of the second artificial muscle is connected to the retraction rod through a connecting member located on the extension rod connecting member, and the other end of the second artificial muscle passes through the upper static platform or the lower static platform and is connected to the upper static platform or the lower static platform near the other side to realize the retraction drive of the retraction rod.

[0016] Preferably, the second artificial muscle includes an artificial muscle and a traction rope, and the artificial muscle and the traction rope are connected in sequence.

[0017] Furthermore, the leg further includes a plurality of support rods, and the limiting ring is connected to the upper static platform or the lower static platform through the plurality of support rods.

[0018] Furthermore, the foot is a rigid flat plate and is rotationally connected to the lower end moving platform.

[0019] The present invention has the following effects compared with the prior art:

[0020] 1. The knee - bending part of the present invention is omitted, and artificial muscles are adopted in the legs. It can not only play a driving role, but also simplify the structural complexity of the whole robot, making the structure of the present invention simple, with a smaller volume and lighter weight, thus reducing the moment of inertia of the robot.

[0021] 2. The driving joints of the present invention are artificial muscles, which are flexible, shock - resistant, and have a large output force.

[0022] 3. The present invention has all the movement capabilities of a bionic lower limb and has a high degree of flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the overall schematic diagram of the parallel - knee - straight - leg biped robot driven by artificial muscles of the present invention;

[0024] Figure 2 is the schematic diagram of the biped robot of the present invention taking a step forward;

[0025] Figure 3 is the schematic diagram of the biped robot of the present invention taking a step to the side;

[0026] Figure 4 is the schematic diagram of the biped robot of the present invention standing on one leg;

[0027] Figure 5 is the schematic diagram of the four - link 2R1T three - degree - of - freedom parallel mechanism of the present invention;

[0028] Figure 6 is the schematic diagram of the driving scheme of the 2R1T parallel mechanism of the leg of the present invention.

[0029] DESCRIPTION OF THE REFERENCE NUMERALS:

[0030] 1. Hip, 1 - 1. Rotating joint motor, 1 - 2. Hip connecting piece;

[0031] 2. Leg, 2 - 1. Towing rope, 2 - 2. Extension rod connecting piece, 2 - 3. End passive rotating joint, 2 - 4. Short connecting rod, 2 - 5. Lower end moving platform, 2 - 6. Artificial muscle, 2 - 7. Extension rod, 2 - 8. Linear bearing, 2 - 9. Lower static platform, 2 - 10. Limit ring, 2 - 11. Hook hinge, 2 - 12. Upper static platform, 2 - 13. Support rod, 2 - 14. Upper end moving platform, 2 - 15. Connecting block;

[0032] 3. Foot. DETAILED DESCRIPTION OF THE INVENTION

[0033] DETAILED DESCRIPTION OF THE INVENTION I: In combination with Figures 1 to 6This embodiment includes a hip 1, two legs 2, and feet 3. The legs 2 are legs driven by artificial muscles. The hip 1 is installed on the upper parts of the two legs 2 and drives one leg 2 to rotate respectively. A foot 3 is installed at the lower end of each leg 2.

[0034] Each leg 2 includes an upper static platform 2-12, a lower static platform 2-9, a lower end moving platform 2-5, an upper end moving platform 2-14, eight artificial muscle driving members, and two three-degree-of-freedom parallel mechanisms. The upper static platform 2-12 and the lower static platform 2-9 are arranged parallel to each other up and down. The two three-degree-of-freedom parallel mechanisms are respectively installed on the upper part of the upper static platform 2-12 and the lower part of the lower static platform 2-9. The lower end moving platform 2-5 is located below the three-degree-of-freedom parallel mechanism on the side close to the foot 3 and is connected to the foot 3. The upper end moving platform 2-14 is installed on the upper part of the three-degree-of-freedom parallel mechanism on the side close to the hip 1 and is connected to the hip 1. Every four artificial muscle driving members are grouped together and connected to a three-degree-of-freedom parallel mechanism. And under the drive of the four artificial muscle driving members and the synergistic effect of the lower end moving platform 2-5 and the upper end moving platform 2-14, the pitching and yawing motions of the entire leg 2 are realized.

[0035] The artificial muscle driving member in this embodiment uses a pneumatic artificial muscle, which has multiple unique advantages compared with other forms of drivers. For example: the power / mass ratio is large. Among them, the self-weight of the artificial muscle per unit length is at most 1000g to 1150g, but it can provide a pulling force of 6000N, far exceeding the electric drive components. It can better simulate the movement of human muscles, can be directly used for joint drive without a transmission device, has a higher energy conversion efficiency, and has high reliability and a long service life. It is an ideal bionic driver.

[0036] Specific embodiment two: Combined Figures 1 to 6 This embodiment of the hip 1 includes two rotary joint motors 1-1 and a hip connecting member 1-2. The hip connecting member 1-2 is a long connecting member. The two rotary joint motors 1-1 are symmetrically installed on the hip connecting member 1-2, and the output shaft of each rotary joint motor 1-1 passes through the hip connecting member 1-2 and is respectively connected to the upper end of one leg 2.

[0037] With such a setting, the two rotary joint motors 1-1 drive one leg 2 respectively to achieve rotations at different angles, and the hip connecting member 1-2 plays a role of connection and transition. The other components are the same as those in the first specific embodiment.

[0038] The two ends of the hip connecting member 1-2 in the length direction of this embodiment are arc-shaped, which can reduce the weight of the entire robot and is convenient for production and processing.

[0039] Specific Embodiment 3: In combination with Figures 1 to 6 This embodiment will be described. The three-degree-of-freedom parallel mechanism of this embodiment includes an extension rod connecting member 2-2 and an extension rod 2-7. Four end parts on the lower end moving platform 2-5 or the upper end moving platform 2-14 are respectively provided with an extension rod connecting member 2-2, and an extension rod 2-7 is inserted on each extension rod connecting member 2-2. Two groups of extension rods 2-7 arranged oppositely among the four extension rods 2-7 are respectively an extension rod and a contraction rod. The extension rod and the contraction rod both pass through the upper static platform 2-12 or the lower static platform 2-9 and then extend to the other side and are connected to four artificial muscle driving members.

[0040] With such a setting, the action realized by the three-degree-of-freedom parallel mechanism in this embodiment is provided with driving power by the artificial muscle driving member, and this power drives the extension rod 2-7 to realize the movement of the leg on the lower end moving platform 2-5 or the upper end moving platform 2-14 with multiple degrees of freedom at the same time. Other compositions and connection relationships are the same as those in Specific Embodiment 1 or 2.

[0041] Specific Embodiment 4: In combination with Figures 1 to 6 This embodiment will be described. The structures of the lower end moving platform 2-5 and the upper end moving platform 2-14 in this embodiment are the same;

[0042] The lower end moving platform 2-5 includes an end passive rotating joint 2-3, a Hooke's joint 2-11, a first moving platform 2-5-1 and a second moving platform 2-5-2. The first moving platform 2-5-1 is rotationally installed on the second moving platform 2-5-2 through the end passive rotating joint 2-3. Hooke's joints 2-11 are respectively installed at both ends of the first moving platform 2-5-1 and the second moving platform 2-5-2, and the Hooke's joint 2-11 rotates along the normal direction of the corresponding first moving platform 2-5-1 and second moving platform 2-5-2. The extension rod connecting member 2-2 is installed on the Hooke's joint 2-11, and the Hooke's joint 2-11 has two rotational degrees of freedom.

[0043] With such a setting, the structure is simple and the movement process is smooth. Other compositions and connection relationships are the same as any one of Specific Embodiments 1 to 3.

[0044] Specific Embodiment 5: In combination with Figures 1 to 6 This embodiment will be described. The lower end moving platform 2-5 of this embodiment further includes a short connecting rod 2-4. One end of the short connecting rod 2-4 is rotationally connected to the Hooke's joint 2-11, and the other end of the short connecting rod 2-4 is rotationally connected to the lower part of the extension rod connecting member 2-2.

[0045] With such a setting, the short connecting rod 2-4 and the Hooke joint 2-11 cooperate to prevent the legs from jamming during the execution of actions, making the movement easier and more flexible. The other components and connection relationships are the same as any one of the first to fourth specific embodiments.

[0046] Specific embodiment six: Combining Figures 1 to 6 To illustrate this embodiment, the three-degree-of-freedom parallel mechanism of this embodiment further includes two limit rings 2-10 and a plurality of linear bearings 2-8. The protruding rods 2-7 located on the upper static platform 2-12 or the lower static platform 2-9 and the protruding rods 2-7 located on the limit rings 2-10 are all sleeved with linear bearings 2-8.

[0047] With such a setting, the linear bearings 2-8 facilitate ensuring the straightness of the carbon fiber rods, preventing their displacement changes, and thus improving the leg movement accuracy. The other components and connection relationships are the same as any one of the first to fifth specific embodiments.

[0048] Specific embodiment seven: Combining Figures 1 to 6 To illustrate this embodiment, each group of artificial muscle driving components of this embodiment includes two first artificial muscles and two second artificial muscles.

[0049] One end of the first artificial muscle is connected to the upper static platform 2-12 or the lower static platform 2-9, and the other end of the first artificial muscle is parallel to the protruding rod and is connected to the end of the protruding rod of the upper static platform 2-12 or the lower static platform 2-9 located near the other side through a connecting block 2-15 to realize the extension drive of the protruding rod.

[0050] One end of the second artificial muscle is connected to the retracting rod through a connecting piece located on the protruding rod connecting piece 2-2, and the other end of the second artificial muscle passes through the upper static platform 2-12 or the lower static platform 2-9 and is connected to the upper static platform 2-12 or the lower static platform 2-9 near the other side to realize the retraction drive of the retracting rod.

[0051] With such a setting, it is convenient for the artificial muscle driving components located in the middle part of the legs to provide auxiliary support, ensuring the flexibility and extensibility of the actions. Among them, the first artificial muscle drives the carbon fiber rod to achieve the extension action, and the second artificial muscle drives the carbon fiber rod to achieve the contraction action. The other components and connection relationships are the same as any one of the first to sixth specific embodiments.

[0052] In addition, the second artificial muscle driving component in the present invention is only for artificial muscles, which plays a role of connection and drive, and the installation positions of the second artificial muscle driving components are also arranged relatively and are staggered with the long driving components, facilitating the realization of other actions.

[0053] Specific embodiment eight: Combining Figures 1 to 6Describing this embodiment, the second artificial muscle of this embodiment includes an artificial muscle 2-6 and a traction rope 2-1, and the artificial muscle 2-6 and the traction rope 2-1 are connected in sequence.

[0054] With such a setting, when all the artificial muscles of the mechanism do not contract, the artificial muscles in their original lengths will be squeezed against each other under the action of the mechanism. By connecting the contraction rod through the traction rope, the natural flexibility of the traction rope can offset the internal structural stress generated when all the artificial muscles do not contract, avoiding damage to the artificial muscles caused by the deformation of the artificial muscles due to the internal structural stress. The other components and connection relationships are the same as any one of the first to seventh specific embodiments.

[0055] Specific Embodiment Nine: Combining Figures 1 to 6 Describing this embodiment, the leg 2 of this embodiment further includes a plurality of support rods 2-13, and the limiting ring 2-10 and the upper static platform 2-12 or the lower static platform 2-9 are connected by a plurality of support rods 2-13. With such a setting, it is convenient to ensure the connection strength of the entire leg. The other components and connection relationships are the same as any one of the first to eighth specific embodiments.

[0056] Specific Embodiment Ten: Combining Figures 1 to 6 Describing this embodiment, the foot 3 of this embodiment is a rigid flat plate and is rotatably connected to the lower end moving platform 2-5.

[0057] With such a setting, the structure is simple and the stability is better. The other components and connection relationships are the same as any one of the first to ninth specific embodiments.

[0058] Combining Figures 1 to 6 Describing the embodiments of the present invention:

[0059] As Figure 1 Shown is a parallel direct-knee biped robot driven by artificial muscles of the present invention. The present invention includes a hip 1 driven by a rotational joint motor, legs 2 driven by artificial muscles, and a foot 3. Two rotational joint motors are respectively connected to one leg and the hip. Each leg is composed of a 4-link 2R1T three-degree-of-freedom parallel mechanism 2PRU-R-2PRU sharing a static platform. Each 2R1T parallel mechanism is driven by 4 artificial muscles, and each leg has a total of 8 artificial muscles as driving elements. The moving platforms of the two 2R1T parallel mechanisms are respectively connected to the hip and the foot of the robot. The foot of the robot is a relatively large rigid flat plate for stabilizing the robot.

[0060] Figure 2 , Figure 3 And Figure 4 Are respectively schematic diagrams of the robot of the present invention taking a step forward, taking a step to the side, and standing on one foot.

[0061] As Figure 5Schematic diagram of the 4-link 2R1T three-degree-of-freedom parallel mechanism 2PRU-R-2PRU for the leg of the biped robot described in the present invention. This mechanism is composed of four PRU links. Each link consists of a telescopic rod, a first passive rotating joint fixed at the end of the telescopic rod, a short connecting rod, and a Hooke joint. The telescopic rod is connected to the static platform through a linear bearing. Every two links in the diagonal position form a closed-loop mechanism, and the moving platforms of the two closed-loop mechanisms are hinged through a terminal passive rotating joint. This mechanism realizes the movement of the moving platform of the mechanism along the direction of the telescopic rod and the two-dimensional rotation around any axis in the plane perpendicular to the direction of the telescopic rod by controlling the elongation of the four telescopic rods. The leg of the robot is composed of two identical above-mentioned 2R1T parallel mechanisms, which meet the motion requirements of the biped robot for stepping forward, stepping sideward, and lifting the leg.

[0062] As Figure 6 Control method for the telescopic rod of the 4-link 2R1T three-degree-of-freedom parallel mechanism for the leg of the biped robot described in the present invention. There are two ways to drive the telescopic rod by artificial muscles in the figure. Way 1: One end of the artificial muscle is fixed on the side of the static platform far from the moving platform, so that the other end is close to the moving platform. The end of the artificial muscle is connected to a traction rope, and the other end of the traction rope is connected to the side of the telescopic rod close to the moving platform. At this time, when the artificial muscle contracts, it pulls the telescopic rod to move towards the static platform. Way 2: One end of the artificial muscle is fixed on the side of the static platform close to the moving platform, so that the other end of the artificial muscle is far from the moving platform of the robot. The end of the artificial muscle is directly fixedly connected to the end of the telescopic rod far from the moving platform. At this time, when the artificial muscle contracts, it pulls the telescopic rod to move towards the moving platform. The movement directions of the two movement methods are opposite, antagonistic and coupled to each other, realizing the movement control of the 2R1T parallel mechanism.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An artificial muscle driven parallel straight knee biped robot, comprising a hip (1), two legs (2) and a foot (3), characterized in that: The legs (2) are artificial muscle-driven legs, the hips (1) are mounted on the upper parts of the two legs (2) and drive one leg (2) to rotate respectively, and a foot (3) is mounted on the lower end of each leg (2); Each leg (2) comprises an upper static platform (2-12), a lower static platform (2-9), a lower terminal dynamic platform (2-5), an upper terminal dynamic platform (2-14), eight artificial muscle drive components and two three-degree-of-freedom parallel mechanisms. The upper static platform (2-12) and the lower static platform (2-9) are arranged in parallel up and down, and two three-degree-of-freedom parallel mechanisms are respectively installed on the upper part of the upper static platform (2-12) and the lower part of the lower static platform (2-9), the lower terminal moving platform (2-5) is located at the lower part of the three-degree-of-freedom parallel mechanism close to the foot (3) and connected to the foot (3), and the upper terminal moving platform (2-14) is installed at the upper part of the three-degree-of-freedom parallel mechanism close to the hip (1) and connected to the hip (1); Every four artificial muscle driving components form a group and are connected to a three-degree-of-freedom parallel mechanism, and under the drive of the four artificial muscle driving components and the coordinated action of the lower end moving platform (2-5) and the upper end moving platform (2-14), the pitch and yaw movements of the entire leg (2) are realized.

2. The artificial muscle driven parallel straight knee biped robot according to claim 1, characterized in that: The hip (1) comprises two rotary joint motors (1-1) and a hip connecting piece (1-2); the hip connecting piece (1-2) is a long strip connecting piece; the two rotary joint motors (1-1) are symmetrically mounted on the hip connecting piece (1-2); and the output shaft of each rotary joint motor (1-1) passes through the hip connecting piece (1-2) and is respectively connected to the upper end of a leg (2).

3. The artificial muscle driven parallel straight knee biped robot according to claim 2, characterized in that: The three-degree-of-freedom parallel mechanism comprises an extension rod connecting member (2-2) and an extension rod (2-7). The four ends of the lower end moving platform (2-5) or the upper end moving platform (2-14) are respectively installed with an extension rod connecting piece (2-2), and each extension rod connecting piece (2-2) is inserted with an extension rod (2-7). Two groups of extension rods (2-7) arranged opposite to each other among the four extension rods (2-7) are extension rods and retraction rods, respectively. The extension rods and retraction rods pass through the upper static platform (2-12) or the lower static platform (2-9), extend to the other side, and are connected to four artificial muscle driving parts.

4. The artificial muscle driven parallel straight knee biped robot according to claim 3, characterized in that: The lower end moving platform (2-5) and the upper end moving platform (2-14) have the same structure; The lower terminal moving platform (2-5) includes a terminal passive rotating joint (2-3), a Hooke's joint (2-11), a first moving platform (2-5-1) and a second moving platform (2-5-2). The first moving platform (2-5-1) is rotatably mounted on the second moving platform (2-5-2) via a terminal passive rotation joint (2-3); a Hooke's joint (2-11) is respectively mounted at both ends of the first moving platform (2-5-1) and the second moving platform (2-5-2); and the Hooke's joint (2-11) rotates along the normal direction of the corresponding first moving platform (2-5-1) and the second moving platform (2-5-2); and the Hooke's joint (2-11) has two rotational degrees of freedom.

5. The artificial muscle driven parallel straight knee biped robot according to claim 4, characterized in that: The lower end movable platform (2-5) also includes a short connecting rod (2-4), one end of which is rotatably connected to a Hooke's hinge (2-11), and the other end of which is rotatably connected to the lower part of the extension rod connecting member (2-2).

6. The artificial muscle driven parallel straight knee biped robot according to claim 5, characterized in that: The three-degree-of-freedom parallel mechanism also includes two limit rings (2-10) and a plurality of linear bearings (2-8), and the extension rod (2-7) located on the upper static platform (2-12) or the lower static platform (2-9) and the extension rod (2-7) located on the limit ring (2-10) are both equipped with linear bearings (2-8).

7. The artificial muscle driven parallel straight knee biped robot according to claim 6, characterized in that: Each set of artificial muscle driving elements includes two first artificial muscles and two second artificial muscles. One end of the first artificial muscle is connected to the upper static platform (2-12) or the lower static platform (2-9), and the other end of the first artificial muscle is parallel to the extension rod and is connected to the end of the extension rod of the upper static platform (2-12) or the lower static platform (2-9) located near the other side through a connecting block (2-15) to achieve extension drive of the extension rod; One end of the second artificial muscle is connected to the contraction rod via a connector located on the extension rod connector (2-2), and the other end of the second artificial muscle passes through an upper static platform (2-12) or a lower static platform (2-9) and is connected to the upper static platform (2-12) or the lower static platform (2-9) close to the other side, thereby realizing contraction drive of the contraction rod.

8. The artificial muscle driven parallel straight knee biped robot according to claim 7, characterized in that: The second artificial muscle comprises an artificial muscle (2-6) and a traction rope (2-1), and the artificial muscle (2-6) and the traction rope (2-1) are connected in sequence.

9. The artificial muscle driven parallel straight knee biped robot according to claim 8, characterized in that: The leg part (2) further comprises a plurality of support rods (2-13), and the limiting ring (2-10) and the upper static platform (2-12) or the lower static platform (2-9) are connected via the plurality of support rods (2-13).

10. The artificial muscle driven parallel straight knee biped robot according to claim 1, characterized in that: The foot (3) is a rigid flat plate and is rotatably connected to the lower end moving platform (2-5).

Images