CN113119090B

CN113119090B - Rigid-flexible coupling large-stroke high-load actuator and driving method thereof

Info

Publication number: CN113119090B
Application number: CN202110468316.3A
Authority: CN
Inventors: 许明; 王旭; 孙启民; 胡润泽
Original assignee: Hangzhou Dianzi University
Current assignee: Hangzhou Dianzi University
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2022-05-13
Anticipated expiration: 2041-04-28
Also published as: CN113119090A

Abstract

The invention discloses a rigid-flexible coupling large-stroke high-load actuator and a driving method thereof. The actuator includes a system frame and a plurality of actuator cells. And all the actuator units arranged side by side are arranged on the system frame. The actuator unit comprises a pneumatic artificial muscle, a ratchet strip, a damping system, a first one-way locking mechanism and a second one-way locking mechanism. The pneumatic artificial muscle can stretch and contract. The first one-way locking mechanism and the second one-way locking mechanism are respectively arranged at two ends of the pneumatic artificial muscle. The pneumatic artificial muscle and the pawl rack are both provided with a central channel. The ratchet bar is connected with the pneumatic artificial muscle and the central channels of the two ratchet rack in a sliding way. The first one-way locking mechanism and the second one-way locking mechanism are identical in structure and respectively comprise a pawl rack, a limiting spring, a pawl sliding block, a sliding block platform and an execution air bag. The ratchet bar lifting device can accumulate the stroke of each ratchet bar lifting, and the total stroke length is only related to the length of the ratchet bar, so the ratchet bar lifting device has the characteristic of long stroke.

Description

Rigid-flexible coupling large-stroke high-load actuator and driving method thereof

Technical Field

The invention belongs to the field of actuators, relates to a rigid-flexible coupling artificial muscle actuator for realizing a large stroke, and particularly relates to a pneumatic artificial muscle integrated with a ratchet bar, which can realize high load and stroke accumulation of the actuator.

Background

With the wide application of pneumatic artificial muscles and the innovation and development of related flexible actuators. In the future, flexible actuators such as artificial muscles are increasingly used in practical engineering practice. However, the artificial muscle has project limitation between the stroke length and the load at present; the operation space is unreliable, and the like. In addition, the artificial muscle has compliance, i.e. it is difficult to suppress when there is disturbance force acting externally, and thus a series of problems such as control and precision occur. Therefore, the rigid-flexible coupling large-stroke high-load actuating system is designed to overcome the defects of the traditional linear actuating system, the traditional linear actuator and the like.

Disclosure of Invention

The invention aims to provide a rigid-flexible coupling large-stroke high-load actuator and a driving method thereof.

The invention relates to a rigid-flexible coupling large-stroke high-load actuator which comprises a system frame and a plurality of actuator units. And all the actuator units arranged side by side are arranged on the system frame. The actuator monomer comprises a pneumatic artificial muscle, a ratchet, a damping system, a first one-way locking mechanism and a second one-way locking mechanism. The pneumatic artificial muscle can stretch and contract. The first one-way locking mechanism and the second one-way locking mechanism are respectively arranged at two ends of the pneumatic artificial muscle. A pawl rack in the first one-way locking mechanism is fixed with the system rack. And a pawl rack in the second one-way locking mechanism is connected with the system rack in a sliding manner. The pneumatic artificial muscle and the pawl rack are both provided with a central channel. The ratchet bar is connected with the pneumatic artificial muscle and the central channels of the two ratchet rack in a sliding way.

The first one-way locking mechanism and the second one-way locking mechanism are identical in structure and respectively comprise a pawl rack, a limiting spring, a pawl sliding block, a sliding block platform and an execution air bag. The sliding block platform is fixed in the pawl rack. The pawl slide block is in sliding fit with the slide block platform. And a limiting spring is arranged between the pawl sliding block and the pawl rack. The tip of slider platform is provided with the limiting plate. The limiting plate is positioned between the ratchet bar and the pawl slide block. The execution air bag is installed on the sliding block platform and is located between the pawl sliding block and the limiting plate. The pawl is installed on the pawl slider and is matched with the ratchet.

And a damping system is arranged on the first one-way locking mechanism. When the pawl in the first one-way locking mechanism is separated from the ratchet bar, the damping system is pressed against the ratchet bar to generate friction resistance to the sliding ratchet bar.

Preferably, the damping system comprises a U-shaped pipe, a U-shaped spring, a damping rod and a damping friction block. The U-shaped pipe is fixed on a pawl rack of the first one-way locking mechanism. The openings at the two ends of the U-shaped pipe face the ratchet bars. The damping rod is arranged on the side part of the sliding block platform and is in sliding connection with the sliding block platform. The inner end of the damping rod is close to one end of the U-shaped pipe. The outer end of the damping rod is fixed with the damping friction block. The damping friction block is aligned with the sliding key on the side of the ratchet bar. The damping friction block is used for carrying out friction deceleration on the ratchet strip when the pawl in the first one-way locking mechanism is separated from the ratchet strip. The U-shaped spring is arranged to penetrate through the U-shaped pipe. One end of the U-shaped spring is fixed with the inner end of the damping rod. The other end of the U-shaped spring is fixed with the corresponding pawl slide block.

Preferably, the actuator unit further comprises a safety lock mechanism. The safety lock mechanism is arranged at the outer end of the first one-way locking mechanism. The safety lock mechanism comprises a safety lock rack, a speed gear, a steering gear set and a centrifugal lock wheel. The safety lock frame is cylindrical, and a first cylindrical shaft and a second cylindrical shaft which are parallel to each other are supported in the safety lock frame. The speed gear is mounted on a first cylindrical shaft. The teeth of the speed gear are engaged with the ratchet teeth of the ratchet bar. The steering gear set comprises two steering gears which are respectively arranged on the first cylindrical shaft and the second cylindrical shaft. The two steering gears mesh. The centrifugal locking wheel comprises a locking claw and an oval disc. The elliptical disk is fixed on the second cylindrical shaft. The inner ends of one or more locking claws are rotatably connected with the edge position of the elliptic disc, and the outer ends of the one or more locking claws are outwards overturned to form limit positions. When the locking claw is turned outwards to the limit position, the outer end of the locking claw can hook the ratchet on the ratchet strip.

Preferably, the elliptic disc is provided with bosses corresponding to the number of the locking claws. The boss is provided with a limiting hole. The outer end of the locking claw is provided with a waist-shaped hole. An elastic limiting pin is arranged between the locking claw and the corresponding boss. One end of the elastic limiting pin is provided with a pin column; the pin column extends into the kidney-shaped hole corresponding to the locking claw, and the other end of the pin column is in sliding connection with the limiting hole on the corresponding boss. The end part of the pin column far away from the locking claw is limited with the boss through a shaft shoulder.

Preferably, a torsion spring is arranged between the locking claw and the oval plate. The torsion spring applies an elastic force to the locking claw to turn the outer end of the locking claw inwards.

Preferably, the number of the actuator units is three. The three actuator units are arranged in a regular triangle.

Preferably, the pneumatic artificial muscle adopts Mckiben muscle thorn strips made of elastic materials.

Preferably, one end of the pawl is hinged with the outer side face of the pawl sliding block, and the other end of the pawl is matched with the ratchet on the ratchet strip. A torsion spring is arranged between the pawl and the pawl sliding block.

Preferably, one side surface of the pawl is a concave smooth curved surface, and the other side surface is formed by connecting a convex curved surface and a plane.

The driving method of the rigid-flexible coupling large-stroke high-load actuator comprises the following specific steps:

step one, installing a working platform at the tail end of each ratchet. A weight is loaded on the work platform.

And step two, the pneumatic artificial muscle is driven to shorten, so that the second one-way locking mechanism rises, and the pawl in the second one-way locking mechanism drives the ratchet strip to rise.

And step three, driving the pneumatic artificial muscle to extend, so that the second one-way locking mechanism is lowered, and the pawl is kept static under the support of the first one-way locking mechanism.

And step four, realizing the large-amplitude controllable lifting of the heavy object by repeating the step two and the step three.

When the lifting of the heavy object needs to be relieved, the execution air bags in the first one-way locking mechanism and the second one-way locking mechanism are pressurized. The pawl slide block is pushed to move in the direction away from the ratchet strip, and the pawl is separated from the ratchet of the ratchet strip and is not contacted. Therefore, the ratchet starts to move vertically downward by the weight of the weight. At this time, the damping system performs friction deceleration on the ratchets.

The invention has the beneficial effects that:

1. the invention can accumulate the stroke of each time of lifting the ratchet bar, and the total stroke length is only related to the length of the ratchet bar, thereby having the characteristic of long stroke.

2. The load force of the invention in each lifting process of the ratchet bar and the heavy object is not changed, and the change of the load force cannot be influenced by the stroke, so the load force of the heavy object lifted by the invention is irrelevant to the stroke length.

3. The invention is designed into a rigid-flexible coupling mechanism, can effectively resist mechanical interference and simultaneously comprises flexibility.

4. The damping system and the safety lock mechanism are designed, and can play a reliable protection role when a heavy object is released or the load force of the heavy object exceeds the rated force.

5. The invention comprises a plurality of actuator units, wherein the plurality of actuator units can bear larger load force together, and can drive the working platform to tilt and the like in an asynchronous motion mode of each actuator unit.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a schematic structural view of an actuator unit according to the present invention.

Fig. 3 is an internal schematic view of an actuator cell in the present invention.

FIG. 4 is a first internal schematic view of the second one-way locking mechanism of the present invention.

FIG. 5 is a second internal view of the second unidirectional locking mechanism of the present invention.

Fig. 6 is a schematic view of the combination of the first one-way locking mechanism and the damping system of the present invention.

FIG. 7 is a schematic view of the safety lock mechanism of the present invention when the ratchet bar is unlocked (for clarity of illustration, the safety lock housing is shown separately from the rest of the structure).

FIG. 8 is a schematic view of the present invention with the security lock mechanism locking the ratchet bar (for clarity of illustration, the security lock housing is shown separately from the other structures).

Fig. 9 is a schematic structural view of the centrifugal locking wheel of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Example 1

As shown in fig. 1, a rigid-flexible coupling large-stroke high-load actuator comprises a system frame 2 and a plurality of actuator units 1. The system frame 2 is cylindrical. The actuator units 1 are elongated and in this embodiment are three in number. The three actuator units 1 are arranged in a regular triangle.

As shown in fig. 2, 3 and 4, the actuator unit 1 comprises a pneumatic artificial muscle 6, a ratchet 3, a safety lock mechanism 4, a damping system 9, a first one-way locking mechanism 5 and a second one-way locking mechanism 7. The first one-way locking mechanism 5 and the second one-way locking mechanism 7 are respectively arranged at two ends of the pneumatic artificial muscle 6. The pawl frame 5-1 in the first one-way locking mechanism 5 is fixed with the inner side wall of the system frame 2. The pawl frame 5-1 in the second one-way locking mechanism 7 and the inner side wall of the system frame 2 form a sliding pair. When the pneumatic artificial muscle 6 stretches, the second one-way locking mechanism can be driven to slide along the length direction of the system frame 2. The pneumatic artificial muscle 6 adopts Mckiben muscle which is powered by an external air pressure source, and the Mckiben muscle naturally extends under the pressure relief state and shortens under the pressure charging state. The pneumatic artificial muscle 6 and the two pawl frames 5-1 are both cylindrical. The ratchet bar 3 passes through the central cavity of the pneumatic artificial muscle 6 and the two ratchet rack 5-1 and is matched with the two one-way locking mechanisms to move. The sliding key 3-1 arranged at the side part of the ratchet bar 3 and the sliding groove on the inner side wall of the pawl rack 5-1 form a sliding pair. The ratchet strip 3 is made of elastic material.

As shown in figures 4, 5 and 6, the first one-way locking mechanism and the second one-way locking mechanism are identical in structure and respectively comprise a pawl rack 5-1, a limiting spring 5-2, a pawl 5-5, a pawl sliding block 5-4, a sliding block platform 5-3 and an execution air bag 5-7. The sliding block platform 5-3 is fixed in the pawl rack 5-1. The pawl slide block 5-4 and the slide groove 5-6 on the slide block platform 5-3 form a slide pair. The sliding direction of the sliding block platform 5-3 is vertical to the length direction of the ratchet strip 3. A limiting spring 5-2 is arranged between the pawl slide block 5-4 and the inner side wall of the pawl rack 5-1. The end part of the sliding block platform 5-3 is provided with a limiting plate. The limiting plate is positioned between the ratchet bar 3 and the pawl slide block 5-4. The execution air bag 5-7 is installed on the sliding block platform 5-3 and is positioned between the pawl sliding block 5-4 and the limiting plate. The side part of the sliding block platform 5-3 is provided with a through hole for leading out the air bag vent pipeline 5-8. One end of the pawl 5-5 is hinged with the outer side surface of the pawl sliding block 5-4, and the other end is matched with the ratchet 3-2 on the ratchet bar 3. A torsion spring is arranged between the pawl 5-5 and the pawl sliding block 5-4. The torsion spring provides the pawl 5-5 with a spring force against the ratchet 3. When the actuating air bag 5-7 is not pressurized, the pawl 5-5 is engaged with the ratchet 3 so that the ratchet 3 can only slide in one direction. When the pressurized inflation of the air bag 5-7 is performed, the slider platform 5-3 is pushed away from the ratchet 3, so that the pawl 5-5 is separated from the ratchet 3. One side surface of the pawl 5-5 is a concave smooth curved surface, and the other side surface is formed by connecting a convex curved surface with a plane.

The damping system 9 is mounted within the first one-way locking mechanism 5. The damping system 9 comprises a U-shaped pipe 9-2, a U-shaped spring 9-5, a connecting rod 9-1, a damping rod 9-3 and a damping friction block 9-4. The U-shaped pipe 9-2 is fixed on a pawl rack 5-1 of the first one-way locking mechanism. The two ends of the U-shaped pipe 9-2 are opened towards the sliding key 3-1 at the side part of the ratchet bar 3. The bent part of the U-shaped pipe 9-2 is far away from the ratchet strip 3. The damping rod 9-3 is arranged on the side part of the sliding block platform 5-3 and is connected with the sliding block platform 5-3 in a sliding way. The inner end of the damping rod 9-3 is close to one of the ends of the U-shaped tube 9-2. The outer end of the damping rod 9-3 is fixed with a damping friction block 9-4. The damping friction block 9-4 is aligned with the sliding key 3-1 at the side of the ratchet 3. A cuboid friction material at the outer end of the damping friction block 9-4. The U-shaped spring 9-5 is arranged to penetrate through the U-shaped pipe 9-2. One end of the U-shaped spring 9-5 is fixed with the inner end of the damping rod 9-3. The other end of the U-shaped spring 9-5 is fixed with the corresponding pawl slide block 5-4 through a connecting rod 9-1. When the pawl slide block 5-4 slides to the direction far away from the ratchet strip 3, the U-shaped spring 9-5 is driven to move. The U-shaped spring 9-5 pushes the damping rod 9-3 to move towards the ratchet 3 after being guided by the U-shaped pipe 9-2, so that the damping friction block 9-4 is in contact with the sliding key 3-1, the ratchet 3 is decelerated, and the phenomenon that the ratchet 3 moves too fast when the ratchet loses the restraint of the pawl 5-5 is avoided.

As shown in fig. 7 and 8, the safety lock mechanism 4 is mounted at the outer end of the first unidirectional locking mechanism 5. The safety lock mechanism 4 comprises a safety lock frame 4-1, a speed gear 4-2, a steering gear set 4-3 and a centrifugal lock wheel 8. The safety lock frame 4-1 is a hollow cylinder without an upper bottom surface and a lower bottom surface, and a first cylindrical shaft and a second cylindrical shaft which are parallel to each other are arranged inside the safety lock frame. The inner hole of the speed gear 4-2 is coaxially matched with a first cylindrical shaft in the safety lock rack 4-1. The teeth of the speed gear 4-2 are in contact with the ratchet teeth 3-2 of the ratchet bar 3. The steering gear set 4-3 includes two steering gears mounted on the first cylindrical shaft and the second cylindrical shaft, respectively. The two steering gears mesh.

As shown in fig. 9, the centrifugal locking wheel 8 includes a locking claw 8-1, an oval disk 8-2, and an elastic restricting pin 8-3. The central hole of the elliptic disc 8-2 is coaxially connected with the second cylindrical shaft. The outer end of an oval disc 8-2 of the centrifugal lock wheel is provided with two bosses, and the bosses are provided with two limiting holes 8-4. Two shaft holes 8-5 are arranged at the outer end of the oval plate 8-2 of the centrifugal lock wheel. The elastic limiting pin 8-3 of the centrifugal lock wheel 8 is a T-shaped pin rod made of elastic materials, and the diameter of a cylinder at the end part is larger. The inner ends of the two locking claws 8-1 are respectively and rotatably connected with two shaft holes 8-5 on the elliptic disc 8-2. The outer ends of the two locking claws 8-1 are provided with waist-shaped holes. One end of the elastic limiting pin 8-3 is provided with a pin column; the pin column extends into the kidney-shaped hole corresponding to the locking claw 8-1, and the other end of the pin column is in sliding connection with the limiting hole 8-4 on the corresponding boss. The end part of the pin column far away from the locking claw 8-1 is limited with the lug boss through a shaft shoulder. A torsion spring is arranged between the locking claw 8-1 and the elliptic disc 8-2. The torsion spring applies an elastic force to the locking claw 8-1 to turn the outer end of the locking claw 8-1 inward. The locking pawl 8-1 is aligned with the ratchet 3-1 on the ratchet bar 3. When the ratchet 3 slides downwards, the speed poking gear 4-2 rotates, so that the centrifugal lock wheel 8 is driven to rotate. When the centrifugal lock wheel 8 rotates, the outer end of the lock claw 8-1 is turned outwards under the centrifugal action, and when the lock claw 8-1 is turned over to exceed the preset degree, the lock claw 8-1 catches on the falling ratchet 3, so that the ratchet 3 stops falling rapidly, and the falling speed of the ratchet 3 is reduced in an extreme case.

Each actuator unit 1 corresponds to three control air pressure tubes, and the three control air pressure tubes are respectively communicated with the pneumatic artificial muscle and the execution air bags in the two one-way locking mechanisms, so that the stretching of the pneumatic artificial muscle and the direct switching between locking and unlocking of the two one-way locking mechanisms are realized.

step one, mounting a working platform at the tail ends of the three ratchet strips 3; the tail ends of the three ratchets 3 are compositely connected with the working platform through a sliding-spherical hinge, namely the ratchets 3 and the spherical hinge seat form a spherical pair, and the spherical hinge seat and the working platform form a sliding pair. A weight is loaded on the work platform. In the first one-way locking mechanism 5 and the second one-way locking mechanism 7, the pawl slide block 5-4 is subjected to the thrust action of the limiting spring 5-2, and the pawl slide block 5-4 is close to the ratchet bar 3, so the ratchet 3-2 on the ratchet bar 3 is in forced engagement with the pawl 5-5 of the first one-way locking mechanism 5 and the second one-way locking mechanism 7, the two pawls are subjected to downward load force together, and the pawl slide block 5-4 supports the pawl 5-5 to keep unchanged as the pawl 5-5 is contacted with the pawl slide block 5-4. The whole position of the ratchet 3 is at the bottom.

And step two, an external air pressure source pressurizes the pneumatic artificial muscle 6, and the pneumatic artificial muscle 6 contracts and shortens. Therefore, the position of the first one-way locking mechanism 5 is not changed, the second one-way locking mechanism 7 is lifted, and the pawl 5-5 in the second one-way locking mechanism 7 lifts the ratchet 3. At this time, only the pawl 5-5 in the second one-way locking mechanism receives the load force of the weight and the acceleration force of lifting the weight through the forced engagement with the ratchet 3-2. As the ratchet 3 rises and the first one-way locking mechanism 5 keeps unchanged in position, the ratchet 3-2 in the ratchet 3 is in contact with the curved surface of the pawl 5-5 in the first one-way locking mechanism 6, and the vertical upward acting force acts on the pawl 5-5 of the first one-way locking mechanism 5, and as the cylindrical rod at one end of the pawl 5-5 of the first one-way locking mechanism is coaxially connected with the connecting hole at the upper end of the pawl sliding block 5-4, the pawl 5-5 rotates by taking the axis of the cylindrical rod as the axis until the pawl is separated from the currently contacted ratchet 3-2.

And step three, releasing the pressure of the pneumatic artificial muscle 6 by an external air pressure source, and recovering and lengthening the pneumatic artificial muscle 6. Therefore, the first one-way lock mechanism 5 remains in position and the second one-way lock mechanism 7 descends. At this time, only the pawl 5-5 and the ratchet 3-2 in the first one-way locking mechanism 5 are forced to be engaged and are subjected to the load force of the heavy object, and the ratchet 3 keeps the whole position unchanged. As the second one-way locking mechanism 7 descends and the integral position of the ratchet bar 3 is kept unchanged, the ratchet 3-2 in the ratchet bar 3 is in curved surface contact with the pawl 5-5 in the second one-way locking mechanism 7, and the acting force in the vertical direction acts on the second one-way locking mechanism 7, and as the cylindrical rod at one end of the pawl 5-5 of the second one-way locking mechanism 7 is coaxially connected with the connecting hole at the upper end of the pawl sliding block 5-4, the pawl 5-5 rotates by taking the axis of the cylindrical rod as the axis until the pawl is separated from the currently contacted ratchet 3-2.

And step four, controlling an external air pressure source to continuously release pressure and charge pressure for the pneumatic artificial muscle 6 through an air pressure pipe of the pneumatic artificial muscle 6, and realizing the periodic motion of the step two and the step three, thereby realizing the continuous accumulation of the stroke.

When the lifting of the heavy object needs to be relieved, the external air pressure source pressurizes the execution air bags 5-7 in the first one-way locking mechanism 5 and the second one-way locking mechanism 7. Therefore, the execution air bag 5-7 is pressed to expand to be larger, the pawl slide block 5-4 is pushed to move away from the ratchet 3, and the pawl 5-5 is separated from the ratchet 3-2 of the ratchet 3 and is not contacted. Therefore, the ratchet 3 starts to move vertically downward by the weight of the weight.

At the moment, the connecting rod 9-1 in the damping system 9 moves together with the pawl sliding block 5-4 and is far away from the ratchet bar 3 to drive the U-shaped spring 9-5 to move along the U-shaped pipe 9-2, so that the damping friction block 9-4 slides to contact the ratchet bar 3 and applies pressure to the ratchet bar 3, and the ratchet bar 3 is rubbed by the damping friction block 9-4, so that the ratchet bar 3 is prevented from being rapidly lowered.

When the ratchet moves down too fast and there is a safety hazard, the safety lock mechanism 4 starts to work. Since the teeth of the speed gear 4-2 are in contact with the ratchet teeth 3-2, the ratchet bar 3 is driven to rotate the two gears of the steering gear set 4-3 through the speed gear 4-2 when descending, and thus the centrifugal lock gear 8 rotates. If the speed is too high, the locking claw 8-1 is far away from the axis of the elliptic disc 8-2 by centrifugal acting force, at the moment, the end part of the locking claw 8-1 is in contact with the ratchet 3-2 to bear force, and the ratchet 3 stops descending.

Example 2

The present example differs from example 1 in that: and a spring for providing a resetting force for the ratchet strip is arranged between each ratchet strip and the system frame 2.

Claims

1. A rigid-flexible coupling large-stroke high-load actuator comprises a system frame (2) and a plurality of actuator units (1); the method is characterized in that: each actuator single body (1) arranged side by side is arranged on the system frame (2); the actuator single body (1) comprises a pneumatic artificial muscle (6), a ratchet bar (3), a damping system (9), a first one-way locking mechanism (5) and a second one-way locking mechanism (7); the pneumatic artificial muscle (6) can stretch; the first one-way locking mechanism (5) and the second one-way locking mechanism (7) are respectively arranged at two ends of the pneumatic artificial muscle (6); a pawl rack (5-1) in the first one-way locking mechanism (5) is fixed with the system rack (2); a pawl rack (5-1) in the second one-way locking mechanism (7) is connected with the system rack (2) in a sliding way; the pneumatic artificial muscle (6) and the pawl rack (5-1) are both provided with a central channel; the ratchet bar (3) is connected with the pneumatic artificial muscle (6) and the central channels of the two ratchet rack (5-1) in a sliding way;

the first one-way locking mechanism (5) and the second one-way locking mechanism (7) are identical in structure and respectively comprise a pawl rack (5-1), a limiting spring (5-2), a pawl (5-5), a pawl sliding block (5-4), a sliding block platform (5-3) and an execution air bag (5-7); the sliding block platform (5-3) is fixed in the pawl rack (5-1); the pawl slide block (5-4) is in sliding fit with the slide block platform (5-3); a limiting spring (5-2) is arranged between the pawl sliding block (5-4) and the pawl rack (5-1); a limiting plate is arranged at the end part of the sliding block platform (5-3); the limiting plate is positioned between the ratchet bar (3) and the pawl sliding block (5-4); the execution air bag (5-7) is arranged on the sliding block platform (5-3) and is positioned between the pawl sliding block (5-4) and the limiting plate; the pawl (5-5) is arranged on the pawl sliding block (5-4) and is matched with the ratchet (3-2); one end of the pawl (5-5) is hinged with the outer side surface of the pawl sliding block (5-4), and the other end of the pawl is matched with the ratchet (3-2) on the ratchet bar (3); a torsion spring is arranged between the pawl (5-5) and the pawl sliding block (5-4); one side surface of the pawl (5-5) is an inwards concave smooth curved surface, and the other side surface is formed by connecting an outwards convex curved surface with a plane;

a damping system (9) is arranged on the first one-way locking mechanism (5); when the pawl (5-5) in the first one-way locking mechanism (5) is separated from the ratchet bar (3), the damping system (9) is abutted against the ratchet bar to generate friction resistance on the sliding ratchet bar.

2. A rigid-flexible coupled large stroke high load actuator according to claim 1, wherein: the damping system (9) comprises a U-shaped pipe (9-2), a U-shaped spring (9-5), a damping rod (9-3) and a damping friction block (9-4); the U-shaped pipe (9-2) is fixed on a pawl rack (5-1) of the first one-way locking mechanism; openings at two ends of the U-shaped pipe (9-2) face the ratchet strips (3); the damping rod (9-3) is arranged on the side part of the sliding block platform (5-3) and is in sliding connection with the sliding block platform (5-3); the inner end of the damping rod (9-3) is close to one end of the U-shaped pipe (9-2); the outer end of the damping rod (9-3) is fixed with the damping friction block (9-4); the damping friction block (9-4) is aligned with the sliding key (3-1) at the side part of the ratchet bar (3); the damping friction block (9-4) is used for performing friction deceleration on the ratchet bar (3) when the pawl (5-5) in the first one-way locking mechanism (5) is separated from the ratchet bar (3); the U-shaped spring (9-5) is arranged to penetrate through the U-shaped pipe (9-2); one end of the U-shaped spring (9-5) is fixed with the inner end of the damping rod (9-3); the other end of the U-shaped spring (9-5) is fixed with the corresponding pawl slide block (5-4).

3. A rigid-flexible coupled large stroke high load actuator according to claim 1, wherein: the actuator single body (1) further comprises a safety lock mechanism (4); the safety lock mechanism (4) is arranged at the outer end of the first one-way locking mechanism (5); the safety lock mechanism (4) comprises a safety lock rack (4-1), a speed gear (4-2), a steering gear set (4-3) and a centrifugal lock wheel (8); the safety lock frame (4-1) is cylindrical, and a first cylindrical shaft and a second cylindrical shaft which are parallel to each other are supported inside the safety lock frame; the speed gear (4-2) is arranged on the first cylindrical shaft; the gear teeth of the speed gear (4-2) are meshed with the ratchets (3-2) of the ratchet bar (3); the steering gear set (4-3) comprises two steering gears which are respectively arranged on the first cylindrical shaft and the second cylindrical shaft; two steering gears are meshed; the centrifugal locking wheel (8) comprises a locking claw (8-1) and an oval disc (8-2); the elliptic disc (8-2) is fixed on the second cylindrical shaft; the inner ends of one or more locking claws (8-1) are rotatably connected with the edge position of the elliptic disc (8-2), and the outer ends are outwards turned to form limit positions; when the locking claw (8-1) is turned outwards to the limit position, the outer end of the locking claw (8-1) can hook the ratchet on the ratchet strip (3).

4. A rigid-flexible coupled large stroke high load actuator according to claim 3, wherein: the elliptic disc (8-2) is provided with bosses corresponding to the number of the locking claws; the boss is provided with a limiting hole (8-4); the outer end of the locking claw (8-1) is provided with a waist-shaped hole; an elastic limiting pin (8-3) is arranged between the locking claw (8-1) and the corresponding boss; one end of the elastic limiting pin (8-3) is provided with a pin column; the pin column extends into the kidney-shaped hole of the corresponding locking claw (8-1), and the other end of the pin column is in sliding connection with the limiting hole (8-4) on the corresponding boss; the end part of the pin column far away from the locking claw (8-1) is limited with the lug boss through a shaft shoulder.

5. A rigid-flexible coupled large stroke high load actuator according to claim 3, wherein: a torsion spring is arranged between the locking claw (8-1) and the elliptic disc (8-2); the torsion spring applies elasticity to the locking claw (8-1) to enable the outer end of the locking claw (8-1) to turn inwards.

6. A rigid-flexible coupled large stroke high load actuator according to claim 1, wherein: the number of the actuator units (1) is three; the three actuator single bodies (1) are arranged in a regular triangle.

7. A rigid-flexible coupled large stroke high load actuator according to claim 1, wherein: the pneumatic artificial muscle (6) is wheat basic muscle, and the thorn strips (3) are made of elastic materials.

8. A method of driving a rigid-flex coupled large-stroke high-load actuator as claimed in claim 1, wherein: step one, installing a working platform at the tail end of each ratchet (3); loading a heavy object on the working platform;

step two, the pneumatic artificial muscle (6) is driven to shorten, so that the second one-way locking mechanism (7) rises, and the pawl (5-5) in the second one-way locking mechanism (7) drives the ratchet bar (3) to rise;

driving the pneumatic artificial muscle (6) to extend to enable the second one-way locking mechanism (7) to be lowered, and enabling the pawl (5-5) to be kept static under the support of the first one-way locking mechanism (5);

step four, realizing the large-amplitude controllable lifting of the heavy object by repeating the step two and the step three;

when the lifting of the heavy object needs to be relieved, the execution air bags (5-7) in the first one-way locking mechanism (5) and the second one-way locking mechanism (7) are pressurized; the pawl sliding block (5-4) is pushed to move towards the direction far away from the ratchet strip (3), and the pawl (5-5) is separated from the ratchet (3-2) of the ratchet strip (3) and is not contacted; therefore, the ratchet (3) starts to move vertically downwards under the action of the gravity of the weight; at the moment, the damping system (9) performs friction deceleration on the ratchet (3).