Walking robot and its walking method

Abstract

A walking robot and its walking method are provided. The walking robot includes a walking gear, a first rack, a second rack, and a plurality of grippers. The first rack meshes with the walking gear and extends along the walking direction of the walking robot. The second rack meshes with the walking gear and is parallel to the first rack. During the rotation of the walking gear, the first rack and the second rack can move toward opposite sides along the walking direction. The grippers are used to grip or release a target object. One of the plurality of grippers is fixed to the first rack, and another of the plurality of grippers is fixed to the second rack. In this way, the walking robot can have a shorter walking time and has higher driving efficiency and stability.

Description

Technical Field

[0001] The present application relates to the field of robots, and more specifically to a walking robot and a walking method thereof. Background Art

[0002] The construction of intelligent mines is directly related to the progress of the intelligentization of my country's national economy and society. The construction of intelligent mines is the core technical support for the high-quality development of the coal industry. The construction of intelligent mines deeply integrates artificial intelligence, industrial Internet of Things, cloud computing, big data, robots, intelligent equipment, etc. with coal mining and utilization, forming an intelligent system with comprehensive perception, real-time interconnection, analysis and decision-making, autonomous learning, dynamic prediction, and collaborative control, realizing the intelligent operation of the entire process of mining, transportation, washing, etc. This is of great significance to improving the level of mine safety production and ensuring the stable supply of underground resources.

[0003] In the whole process of coal resource development, detailed exploration of geological conditions is the basic link. Identifying and reconstructing transparent geological conditions for coal mining is the basic guarantee for accurate mining and clean utilization. In the current 3D modeling process of coal mining working faces, static modeling information is mainly used from the acquired coal mining working face data to construct a 3D static model of the working face. There is insufficient attention to the information on the dynamic changes of coal seams during mining, and most of the geological data is obtained through scanning instruments at fixed working points. This method has low flexibility and insufficient data integrity, and cannot meet the requirements of accurate mining. Summary of the invention

[0004] This application is made in view of the above-mentioned state of the prior art. The purpose of this application is to provide a walking robot that can overcome at least one of the disadvantages described in the above-mentioned background technology.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions.

[0006] The present application provides a walking robot as follows, which includes: a walking gear; a first rack meshing with the walking gear, the first rack extending along the walking direction of the walking robot; a second rack meshing with the walking gear, the second rack being parallel to the first rack, and during the rotation of the walking gear, the first rack and the second rack can move toward opposite sides along the walking direction; and a plurality of jaws, the jaws being used to clamp or release a target object, one of the plurality of jaws being fixed to the first rack, and another of the plurality of jaws being fixed to the second rack.

[0007] In an alternative embodiment, the jaw includes a first four-bar mechanism, a second four-bar mechanism, a first clamping body, a second clamping body, and a jaw motor. The first four-bar mechanism includes a first driving rod and a first connecting rod. The first driving rod is torsionally connected to the jaw motor, and the first clamping body is fixed to the first connecting rod. The second four-bar mechanism includes a second driving rod and a second connecting rod. The second driving rod is torsionally connected to the jaw motor, and the second clamping body is fixed to the second connecting rod.

[0008] In another alternative embodiment, the first clamping body has a first clamping surface, which is a cylindrical surface. The straight generatrix of the first clamping surface is parallel to the traveling direction. The second clamping body has a second clamping surface, which is a cylindrical surface. The straight generatrix of the second clamping surface is parallel to the traveling direction. The first clamping surface and the second clamping surface face each other.

[0009] In another alternative embodiment, the length of the first clamping surface in the traveling direction is different from the length of the second clamping surface in the traveling direction. The first clamping body of one jaw and the second clamping body of the other jaw clamp the target object from one side, and the second clamping body of one jaw and the first clamping body of the other jaw clamp the target object from the other side opposite to the one side.

[0010] In another alternative embodiment, an anti-slip pad is further included, and the anti-slip pad adheres to the first clamping surface and the second clamping surface.

[0011] In another alternative embodiment, the jaw further includes a guide body, which extends in the vertical direction of the traveling direction. The frames of the first four-bar mechanism and the second four-bar mechanism are slidably connected to the guide body.

[0012] In another alternative embodiment, the jaw further includes a driving gear and a driven gear. The driving gear is torsionally connected to the first driving rod, and the driven gear is torsionally connected to the second driving rod. The driving gear meshes with the driven gear.

[0013] In another alternative embodiment, a base body, a supporting jaw, and a supporting wheel are further included. The traveling gear is pivotally connected to the base body. The first rack and the second rack are slidably connected to the base body. The supporting jaw defines a space for accommodating a part of the target object, and the supporting jaw is disposed on the base body. The supporting wheel is pivotally connected to the base body, and the supporting wheel abuts against the target object. The rotation axis of the supporting wheel is perpendicular to the traveling direction.

[0014] In another alternative solution, it further includes a first guide rail, a first slider, a second guide rail, and a second slider. The first slider is slidably connected to the first guide rail, the first rack is fixed to the first slider, the second slider is slidably connected to the second guide rail, the second rack is fixed to the second slider, and the first guide rail is parallel to and fixedly opposed to the second guide rail.

[0015] The present application also provides a walking method for the above-mentioned walking robot, and the walking method includes: making one gripper in a released state and the other gripper in a clamped state; making the one gripper walk a first distance along the walking direction away from the other gripper; making the one gripper in a clamped state and the other gripper in a released state; making the other gripper walk a second distance along the walking direction towards the one gripper; and making the other gripper in a clamped state.

[0016] In an alternative solution, the first distance is the same as the second distance.

[0017] In another alternative solution, making the one gripper walk the first distance includes making the walking gear located at one end of the first rack and the other end of the second rack, and / or making the other gripper walk the second distance includes making the walking gear located at the other end of the first rack and one end of the second rack.

[0018] By adopting the above technical solution, the walking gear can move along the walking direction, enabling one gripper and the other gripper to quickly move away from and close to each other, thereby saving the movement time of the walking robot. In addition, the gear-rack transmission structure can reduce the number of motors and electrical components of the walking robot, enabling the walking robot to have high driving efficiency and stability. Description of the Drawings

[0019] Figure 1 Shows a schematic diagram of a walking robot according to an embodiment of the present application.

[0020] Description of the Reference Numerals

[0021] 1 Walking assembly; 11 Base body; 12 First guide rail; 13 First slider; 14 First walking bracket; 15 First rack; 16 Second guide rail; 17 Second walking bracket; 18 Second rack; 19 Walking gear;

[0022] 2 clamping jaws; 21 guide body; 22 clamping jaw bracket; 23 driving gear; 24 first driving rod; 25 first connecting rod; 26 first driven rod; 27 first clamping body; 28 driven gear; 29 second driving rod; 2a second connecting rod; 2b second driven rod; 2c second clamping body; 2d anti-slip pad; 2e first clamping jaw; 2f second clamping jaw;

[0023] 3 anti-falling component; 31 first arm; 32 second arm; 33 supporting claw; 331 first supporting body; 332 second supporting body; 34 supporting wheel;

[0024] A walking direction. Specific embodiments

[0025] The exemplary embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not used to exhaust all feasible ways of the present application, nor to limit the scope of the present application.

[0026] In the present application, unless otherwise specified, "the first driving rod 24", "the first driven rod 26", "the second driving rod 29" and "the second driven rod 2b" refer to the connecting rods in the four-bar mechanism, and "the first connecting rod 25" and "the second connecting rod 2a" refer to the connecting rods in the four-bar mechanism. Among them, "the first driving rod 24" and "the second driving rod 29" are driving parts, and "the first connecting rod 25", "the second connecting rod 2a", "the first driven rod 26" and "the second driven rod 2b" are driven parts. "Torsion-resistant connection" means a connection that can transmit torque.

[0027] Figure 1 A walking robot according to an embodiment of the present application is shown, and in particular, a walking robot suitable for three-dimensional modeling of a coal mining face is shown. For example, in this embodiment, multiple coal shearer guardrails (examples of target objects) can be joined together to form a track, and the walking robot can carry a laser scanner and walk along the coal shearer guardrail. The walking robot may include a walking assembly 1, a clamping jaw 2, an anti-falling component 3, and a control component.

[0028] The walking assembly 1 may include a base body 11, a first guide rail 12, a first slider 13, a first walking bracket 14, a first rack 15, a second guide rail 16, a second slider, a second walking bracket 17, a second rack 18, a walking gear 19, and a walking motor (not shown in the figure). Specifically, the first guide rail 12 may be fixed to the base body 11 and linearly extend in the walking direction A of the walking robot. Two first sliders 13 may be mounted on the first guide rail 12. The first walking bracket 14 may be fixed to the first slider 13. The first rack 15 may be fixed to the first walking bracket 14 and linearly extend along the walking direction A, such that the first walking bracket 14 and the first rack 15 can integrally slide along the first guide rail 12. Correspondingly, the second guide rail 16, the second slider, the second walking bracket 17, and the second rack 18 may adopt a similar arrangement. Among them, the second guide rail 16 may be parallel to and fixed to the first guide rail 12. The tooth portions of the first rack 15 and the second rack 18 may be arranged facing each other. The walking gear 19 may be pivotally connected to the base body 11. The first rack 15 and the second rack 18 may both be engaged with the walking gear 19. The walking motor may be mounted on the base body 11 and torsionally connected to the walking gear 19. When the walking motor drives the walking gear 19 to rotate, the first walking bracket 14 and the second walking bracket 17 may slide toward opposite sides.

[0029] The jaw 2 may include a guide body 21, a jaw bracket 22, a driving gear 23, a first driving rod 24, a first connecting rod 25, a first driven rod 26, a first clamping body 27, a driven gear 28, a second driving rod 29, a second connecting rod 2a, a second driven rod 2b, a second clamping body 2c, an anti-slip pad 2d, a bracket motor (not shown in the figure), and a jaw motor (not shown in the figure). In this embodiment, one of the two jaws 2 (the first jaw 2e) may be fixed to the first walking bracket 14, and the other of the two jaws 2 (the second jaw 2f) may be fixed to the second walking bracket 17. The first jaw 2e and the second jaw 2f may have the same structure and both have a first clamping body 27 and a second clamping body 2c facing each other. The structure of the jaw 2 will be described below taking the first jaw 2e as an example.

[0030] Specifically, the guiding body 21 can be columnar and fixed to the first traveling bracket 14. The two guiding bodies 21 can extend in the vertical direction perpendicular to the traveling direction A and are arranged side by side. The jaw bracket 22 can be mounted on the guiding body 21, and the bracket motor can drive the jaw bracket 22 to slide along the guiding body 21. When the adjacent shearer guardrails are not aligned, the first clamping body 27 and the second clamping body 2c can slide along the guiding body 21 to align the shearer guardrails. The driving gear 23 can be pivotally connected to the jaw bracket 22. The first driving rod 24, the first connecting rod 25, the first driven rod 26, and the jaw bracket 22 can form a first four-bar mechanism, and the two first four-bar mechanisms can be located on both sides of the driving gear 23 respectively. The jaw bracket 22 can serve as the frame of the first four-bar mechanism, and the first driving rod 24 can be torsionally connected to the driving gear 23. The first clamping body 27 can be fixed to the free ends of the two first connecting rods 25. The first clamping body 27 can have a first clamping surface. The first clamping surface can be a cylindrical surface, and the straight generatrix of the first clamping surface can be parallel to the traveling direction A. The anti-slip pad 2d can be attached to the first clamping surface.

[0031] The driven gear 28 can be pivotally connected to the jaw bracket 22 and meshed with the driving gear 23. The second driving rod 29, the second connecting rod 2a, the second driven rod 2b, and the jaw bracket 22 can form a second four-bar mechanism. Among them, the jaw bracket 22 can serve as the frame of the second four-bar mechanism, and the second driving rod 29 can be torsionally connected to the driven gear 28. The second clamping body 2c can be fixed to the free end of the second connecting rod 2a. The second clamping body 2c can have a second clamping surface. The second clamping surface can be a cylindrical surface, and the straight generatrix of the second clamping surface can be parallel to the traveling direction A. The anti-slip pad 2d can be attached to the second clamping surface.

[0032] The jaw motor can be torsionally connected to the driving gear 23. When the jaw motor drives the driving gear 23 to rotate forward, the first clamping body 27 can approach the jaw bracket 22 while moving away from the second clamping body 2c. The driven gear 28 can be driven by the driving gear 23, so that the second clamping body 2c can approach the jaw bracket 22 while moving away from the first clamping body 27. In this way, the first jaw 2e completes the loosening action.

[0033] When the jaw motor drives the driving gear 23 to rotate in the reverse direction (the direction opposite to the forward direction), the first clamping body 27 can move away from the jaw bracket 22 while approaching the second clamping body 2c. The driven gear 28 can be driven by the driving gear 23, so that the second clamping body 2c can move away from the jaw bracket 22 while approaching the first clamping body 27. In this way, the first jaw 2e completes the clamping action. When the first jaw 2e is in the clamping state, the first clamping surface can be arranged facing the second clamping surface and enclose a substantially columnar space.

[0034] Further, the length of the first clamping body 27 in the traveling direction A can be greater than the length of the second clamping body 2c in the traveling direction A. The first clamping body 27 of the first jaw 2e and the second clamping body 2c of the second jaw 2f can clamp the shearer guardrail from one side ( Figure 1 the upper side in Figure 1 ), and the second clamping body 2c of the first jaw 2e and the first clamping body 27 of the second jaw 2f can clamp the shearer guardrail from the other side (

[0035] the lower side in

[0036] ). In this way, by making the two jaws 2 adopt a "positive and negative grip" clamping method, that is, the first jaw 2e adopts a clamping method similar to the positive grip of a human hand, while the second jaw 2f adopts a clamping method similar to the reverse grip of a human hand, the walking robot can stably clamp the shearer guardrail.

[0037] The anti-falling component 3 can include a first arm 31, a second arm 32, a support claw 33, and a support wheel 34. Specifically, one end of the first arm 31 can be fixed to the base body 11, and a support claw 33 can be provided at the other end of the first arm 31. The two first arms 31 can be arranged at intervals such that the two jaws 2 are located between the two support claws 33. The support claw 33 can include a first support body 331 and a second support body 332. The first support body 331 can be generally U-shaped, and the second support body 332 can be generally T-shaped. The first support body 331 can be fixed to the free end of the first arm 31, and the two second support bodies 332 can be pivotally connected to the first support body 331. The user can rotate the second support body 332 so that the first support body 331 and the second support body 332 enclose a space for accommodating a part of the shearer guardrail. By locking the second support body 332, a part of the shearer guardrail can be restricted in the above space. The user can rotate the second support body 332 to open the support claw 33, so that the support claw 33 can be easily installed on the shearer guardrail, or the support claw 33 can be easily separated from the shearer guardrail. When the walking robot is walking normally, the support claw 33 can be spaced apart from the shearer guardrail or there is only less contact, so that the walking robot has a smaller walking resistance. In addition, the ends of the two second support bodies 332 can be spaced apart from each other, so that the support claw 33 will not interfere with the shearer guardrail. When the jaw 2 fails, the support claw 33 can be hooked on the shearer guardrail to prevent the walking robot from falling.One end of the second arm 32 can be fixed to the base body 11, and the other end of the second arm 32 can be pivotally connected to the support wheel 34. The rotation axis of the support wheel 34 can be perpendicular to the traveling direction A, and the support wheel 34 can abut against the side wall surface of the shearer guardrail. When the walking robot travels, the support wheel 34 can roll on the side wall surface of the shearer guardrail. In this way, the support wheel 34 can cooperate with the clamping jaw 2, so that the walking robot has multiple points of contact with the shearer guardrail, and the support wheel 34 can support the walking robot to prevent the walking robot from tipping over. In addition, when there is a discontinuity in the shearer guardrail, the support wheel 34 can roll over the discontinuity, enabling the walking robot to pass through the discontinuity smoothly.

[0038] The control component can include a power supply and a controller. Among them, the power supply can supply power to the entire walking robot. The controller can be electrically connected to the walking motor, the bracket motor, and the clamping jaw motor, and the user can communicate with the controller through the host computer to control the walking robot. The control component can meet the requirements of explosion-proof, dust-proof, waterproof, and anti-collision in the mine. For example, the control component can meet the national standard of the People's Republic of China with the standard number GB / T3836.1-2021.

[0039] The following introduces the walking method of the walking robot, which generally can include:

[0040] Make the first clamping jaw 2e in the open state and the second clamping jaw 2f in the clamping state;

[0041] Make the first clamping jaw 2e walk a first distance along the traveling direction A in a manner away from the second clamping jaw 2f;

[0042] Make the first clamping jaw 2e in the clamping state and the second clamping jaw 2f in the open state;

[0043] Make the second clamping jaw 2f walk a second distance along the traveling direction A in a manner close to the first clamping jaw 2e; and

[0044] Make the second clamping jaw 2f in the clamping state.

[0045] Specifically, the user can pre-clamp the shearer guardrail with the first clamping jaw 2e and the second clamping jaw 2f. After that, the first clamping jaw 2e can be made in the open state. The walking gear 19 can rotate forward ( Figure 1 the clockwise direction in Figure 1 ), so that the first rack 15 and the walking gear 19 move Figure 1 to the right in

[0046] ), so that the first clamping jaw 2e moves away from the second clamping jaw 2f in the traveling direction A and walks a first distance. After the first clamping jaw 2e reaches the target position, the first clamping jaw 2e can be made in the clamping state.

[0046] After that, the second clamping jaw 2f can be made in the open state. The walking gear 19 can rotate in the reverse direction ( Figure 1Rotate counterclockwise (in the counterclockwise direction in the figure), so that the second rack 18 and the traveling gear 19 move towards the Figure 1 right side in the figure), so that the second jaw 2f approaches the first jaw 2e in the traveling direction A and travels a second distance. After the second jaw 2f reaches the target position, the second jaw 2f can be in a clamping state.

[0047] In this way, the walking robot advances one step. By repeating the above actions, the walking robot can advance a specified distance. During walking, the traveling gear 19 can move along the traveling direction A, so that the first jaw 2e and the second jaw 2f can quickly move away from and close to each other, thus saving the movement time of the walking robot. In addition, the rack and pinion transmission structure can reduce the number of motors and electrical components of the walking robot, enabling the walking robot to have higher driving efficiency and stability.

[0048] Furthermore, the first distance and the second distance can be the same. After the first jaw 2e travels the first distance, the traveling gear 19 can be located at one end of the first rack 15 ( Figure 1 the left end in the figure) and the other end of the second rack 18 ( Figure 1 the right end in the figure), so that the first jaw 2e can be as far away from the second jaw 2f as possible. After the second jaw 2f travels the second distance, the traveling gear 19 can be located at the other end of the first rack 15 ( Figure 1 the right end in the figure) and one end of the second rack 18 ( Figure 1 the left end in the figure), so that the second jaw 2f can be as close to the first jaw 2e as possible. Of course, this is not necessary.

[0049] This application has at least the following advantages:

[0050] (i) The traveling gear 19 can move along the traveling direction A, so that the first jaw 2e and the second jaw 2f can quickly move away from and close to each other, thus saving the movement time of the walking robot. In addition, the rack and pinion transmission structure can reduce the number of motors and electrical components of the walking robot, enabling the walking robot to have higher driving efficiency and stability.

[0051] (ii) The two jaws 2 adopt a "positive and negative grip" clamping method, enabling the walking robot to stably hold the coal shearer guardrail.

[0052] (iii) The jaws 2 can slide along the guide body 21 to accurately grip the coal shearer guardrail.

[0053] (iv) When the jaws 2 fail, the support claws 33 can be hooked on the coal shearer guardrail to prevent the walking robot from falling. When there is a break in the coal shearer guardrail, the support wheels 34 can roll over the break, enabling the walking robot to pass through the break smoothly.

[0054] It should be understood that the above embodiments are merely exemplary and are not used to limit the present application. Those skilled in the art can make various modifications and changes to the above embodiments under the teaching of the present application without departing from the scope of the present application.

[0055] It should be understood that the walking robot is not limited to clamping the guardrail of the coal shearer. For example, the walking robot can be used to climb a relatively high building.

[0056] It should be understood that the first rack 15 is not limited to being guided by the first guide rail 12, and the second rack 18 is not limited to being guided by the second guide rail 16. For example, the base body 11 can be provided with a first guide hole for mating with the first rack 15 and a second guide hole for mating with the second rack 18. Or the base body 11 can be provided with a first linear bearing for mating with the first rack 15 and a second linear bearing for mating with the second rack 18.

[0057] It should be understood that the jaw 2 is not limited to the above embodiments. For example, the first clamping body 27 and the second clamping body 2c can be flexible and formed as one body. The first clamping body 27 and the second clamping body 2c can be driven by different motors. The number of jaws 2 is not limited to two, and it can also be three or more.

Claims

1. A walking robot, characterized in that, it includes: a walking gear (19); a first rack (15) that meshes with the walking gear (19), and the first rack (15) extends along the walking direction (A) of the walking robot; a second rack (18) that meshes with the walking gear (19), the second rack (18) is parallel to the first rack (15), and during the rotation of the walking gear (19), the first rack (15) and the second rack (18) can move towards opposite sides along the walking direction (A); a plurality of jaws (2), the jaws (2) are used for clamping or releasing a target object, one of the plurality of jaws (2) is fixed to the first rack (15), and another one of the plurality of jaws (2) is fixed to the second rack (18); and a base body (11), the walking gear (19) is pivotally connected to the base body (11), and the first rack (15) and the second rack (18) are slidably connected to the base body (11), the jaw (2) includes a first four-bar mechanism, a second four-bar mechanism, a first clamping body (27), a second clamping body (2c), and a jaw motor. The first four-bar mechanism includes a first driving rod (24) and a first connecting rod (25). The first driving rod (24) is anti-torsionally connected to the jaw motor, and the first clamping body (27) is fixed to the first connecting rod (25). The second four-bar mechanism includes a second driving rod (29) and a second connecting rod (2a). The second driving rod (29) is anti-torsionally connected to the jaw motor, and the second clamping body (2c) is fixed to the second connecting rod (2a), the first clamping body (27) has a first clamping surface, the first clamping surface is a cylindrical surface, and the straight generatrix of the first clamping surface is parallel to the walking direction (A). The second clamping body (2c) has a second clamping surface, the second clamping surface is a cylindrical surface, and the straight generatrix of the second clamping surface is parallel to the walking direction (A). The first clamping surface and the second clamping surface face each other, the length of the first clamping surface in the walking direction (A) is different from the length of the second clamping surface in the walking direction (A). The first clamping body (27) of one jaw (2) and the second clamping body (2c) of the other jaw (2) clamp the target object from one side, and the second clamping body (2c) of one jaw (2) and the first clamping body (27) of the other jaw (2) clamp the target object from the other side opposite to the one side, The walking robot further includes a first guide rail (12), a first slider (13), a second guide rail (16) and a second slider. The first slider (13) is slidably connected to the first guide rail (12). The first rack (15) is fixed to the first slider (13). The second slider is slidably connected to the second guide rail (16). The second rack (18) is fixed to the second slider. The first guide rail (12) and the second guide rail (16) are parallel and relatively fixed to each other.

2. The walking robot according to claim 1, wherein, it further includes an anti-slip pad (2d), and the anti-slip pad (2d) is attached to the first clamping surface and the second clamping surface.

3. The walking robot according to claim 1, wherein, the jaw (2) further includes a guide body (21). The guide body (21) extends in the vertical direction perpendicular to the walking direction (A). The frame of the first four-bar mechanism and the frame of the second four-bar mechanism are slidably connected to the guide body (21).

4. The walking robot according to claim 1, wherein, the jaw (2) further includes a driving gear (23) and a driven gear (28). The driving gear (23) is torsionally connected to the first driving rod (24). The driven gear (28) is torsionally connected to the second driving rod (29). The driving gear (23) meshes with the driven gear (28).

5. The walking robot according to any one of claims 1 to 4, wherein, it further includes a supporting jaw (33) and a supporting wheel (34), the supporting jaw (33) defines a space for accommodating a part of the target object. The supporting jaw (33) is arranged on the base body (11), the supporting wheel (34) is pivotally connected to the base body (11). The supporting wheel (34) abuts against the target object. The rotation axis of the supporting wheel (34) is perpendicular to the walking direction (A).

6. A walking method of the walking robot according to any one of claims 1 to 5, wherein, it includes: keeping one jaw (2) in a released state and the other jaw (2) in a clamped state; moving one jaw (2) a first distance along the walking direction (A) away from the other jaw (2); keeping one jaw (2) in a clamped state and the other jaw (2) in a released state; moving the other jaw (2) a second distance along the walking direction (A) towards the one jaw (2); and keeping the other jaw (2) in a clamped state.

7. The walking method according to claim 6, wherein, the first distance is the same as the second distance.

8. The walking method according to claim 6, wherein, moving one jaw (2) the first distance includes making the walking gear (19) located at one end of the first rack (15) and the other end of the second rack (18), and / or Moving the other jaw (2) a second distance includes positioning the travel gear (19) at the other end of the first rack (15) and at one end of the second rack (18).

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