CN113829328B - A Flexible Manipulator with Positive Angle Compensation - Google Patents

Abstract

The invention discloses a flexible mechanical arm with forward angle compensation. The flexible mechanical arm is linearly stacked through the segmented flexible units, and the length of the whole flexible mechanical arm can be controlled by selecting the number of stacked segments according to actual needs when the flexible mechanical arm is used, so that the length adjustment design is very simple; through designing each section flexible unit to be become the flexible module of annular arrangement by a plurality of and constitute, all articulate between each flexible module and between four isosceles trapezoid pieces of constituteing each flexible module to can design many haulage ropes as required, when using the haulage rope control flexible arm to shorten, can realize flexible arm's different positions flexible length difference through the work between the different haulage ropes of control, thereby make flexible arm can be crooked to different directions, and not be limited to the flexible of linear direction.

Description

A Flexible Manipulator with Positive Angle Compensation

technical field

The invention relates to the technical field of design of flexible mechanical arms, in particular to a flexible mechanical arm with forward angle compensation.

Background technique

The origami robot is a kind of robot prepared through origami technology research. The origami robot is inspired by the Japanese origami technology. Initially, scientists changed the shape of the paper by studying the way of origami, while using the flexibility and toughness of the paper. , complete target actions and specified tasks, and more and more scientists have devoted themselves to the field of origami robots. However, due to the low stiffness of the origami mechanism, it is difficult to withstand relatively large forces and moments. Therefore, origami robots are difficult for practical application. At the same time, the kinematics model and dynamics model of the origami robot are extremely complex, and because the precision of the origami robot is limited, it is difficult to guarantee the precise control of the robot.

For example, the invention application with publication number CN110394795A discloses a self-folding pneumatic soft manipulator with high storage rate based on origami theory, including a soft driver, upper and lower end cover plates and an inflation system. The soft driver is a cylindrical shell with two The end and the upper and lower end cover plates are sealed and fixed, the inner cavity can be inflated, and the shell is a multi-layer soft laminated structure, which is an airtight layer, an elastic layer, a restrictive layer and a thermal protection layer from the inside to the outside. The topological form of the software driver shell is designed based on the origami theory, which can realize the axial large-stroke telescopic drive, and the inner cavity is inflated through the inflation system to drive and unfold, and the elastic potential energy of the elastic layer is released after the inner cavity is exhausted. Self-folding. The device may also include restraint cables to enable bending actuation.

For another example, the invention application with publication number CN112223259A discloses a high-capacity aerodynamic soft worm robot based on origami theory, including flexible drives, front and rear end cover plates, pneumatic feet and an inflation system. The two ends of the flexible driver are respectively bonded to the front and rear end cover plates, and the flexible driver is stretched by inflating the flexible driver through the inflation system, driving the front exhaust dynamic foot to move forward; Shrink, drive the rear exhaust dynamic foot to move forward, so as to realize the axial large-stroke bionic crawling. The pneumatic foot adjusts the angle between the hinge joint and the ground through the expansion and contraction of the air bag, thereby changing the friction form with the ground to realize unidirectional movement.

In the above-mentioned prior art, the origami structure is controlled by pneumatics, which can only be simply extended and shortened, and cannot actively control the direction of motion; and the design length of the origami structure is fixed and cannot be adjusted according to needs.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a flexible mechanical arm with forward angle compensation based on origami theory.

A flexible mechanical arm with positive angle compensation, including several linearly stacked flexible units, and a drive mechanism for driving each flexible unit to expand and contract;

Each flexible unit includes a plurality of telescopic modules arranged in a ring, each telescopic module includes four isosceles trapezoidal pieces, and the sides of the four isosceles trapezoidal pieces are hinged in turn to form a telescopic module with a quadrangular pyramid structure. When the two telescopic modules are arranged in a ring, the top surface of the truncated pyramid structure faces the inner center of the ring, and the bottom surface of the truncated pyramid structure deviates from the inner center of the ring;

The isosceles trapezoidal sheets used in the telescopic modules in each flexible unit are all of the same size and shape, and the adjacent telescopic modules in each flexible unit are hinged by the upper bottom sides of the two isosceles trapezoidal sheets that are attached to each other; The height of the waist trapezoidal sheet is expressed as h, the upper base is a, and the lower base is b, and each flexible unit includes n telescopic modules, then it satisfies:

The driving mechanism includes: sequentially passing through at least part of the isosceles trapezoidal sheet in each section of the flexible unit, a traction rope that is folded and shortened on at least one side for pulling the flexible unit, and the outer side of the flexible unit at the end, The retractable unit for retracting the traction rope.

The positive angle compensation method provides positive angle compensation for the flexible manipulator. When the flexible manipulator is in the minimum compression state, the angle projected by the telescopic module to the horizontal plane is the smallest. When the flexible manipulator is in the maximum stretch state, the telescopic module projects to the horizontal plane. The angle of the horizontal plane is the largest, and the angle compensation gradually increases during the transition of the flexible manipulator from the maximum tension state to the minimum compression state, providing angle compensation. In order to meet the requirements of maximum stretching and minimum compensation, when the flexible manipulator is in the state of maximum stretching, the angle compensation is set to 0. At this time, each telescopic module is closely attached to each other, and the isosceles trapezoidal piece is determined according to the state at this time. size relationship. When the shape of the isosceles trapezoidal sheet satisfies the above formula, the flexible unit can be stretched to the maximum length. If the relationship deviates from this formula, the flexible unit cannot be stretched to the maximum length when it is folded and stretched. .

Preferably, each flexible unit includes at least 3 telescopic modules. More preferably, each flexible unit includes 3, 4, 6 or 8 telescopic modules.

Preferably, a mounting plate is provided on the outer side of a section of the flexible unit at the end, and the retractable unit is provided on the side of the mounting plate away from the flexible unit, and each traction rope is correspondingly provided with a group of retractable units. The release unit includes a wire take-up reel, and a motor that drives the wire take-up reel to rotate, and the mounting plate is provided with an avoidance hole for the traction rope to pass through.

Preferably, all the telescopic modules of all the flexible units are grouped, and the telescopic modules arranged on the same straight line between adjacent flexible units are grouped and controlled by a traction rope.

Preferably, each flexible unit includes an even number of telescopic modules,

Group all the telescopic modules of all flexible units, and divide the telescopic modules of the same flexible unit into a group.

Each group arranged on the same straight line between adjacent flexible units is divided into a large group, and is controlled by a traction rope.

The flexible mechanical arm of the present invention folds each isosceles trapezoidal sheet in the telescopic module through the traction of the traction rope, and after folding, the traction rope needs to be released to keep the flexible unit in a stretched state, so as to restore the shape of the flexible mechanical arm. In the case of a corresponding recovery drive structure, the flexible manipulator can be used vertically to recover by gravity.

Preferably, the two isosceles trapezoidal sheets are hinged in a hinge structure. More preferably, a torsion spring for keeping the flexible unit in a stretched state is also provided in the hinge structure. The hinge structure includes a hinged hole column located on the side of the isosceles trapezoidal sheet and a shaft core passing through the hinged hole column. A self-recovering torsion spring can be set on the shaft core to achieve the purpose of keeping the flexible unit in a stretched state. During the stretching process of the rope, as long as the torsion force of the torsion spring is overcome, the flexible unit can be folded and compressed, and after the traction rope is released, the torsion spring can provide recovery power to make the flexible mechanical arm stretch and straighten. When the hinge structure is used, the isosceles trapezoidal piece and the corresponding hinged hole column can be integrally formed by 3D printing.

The flexible manipulator of the present invention is linearly stacked through segmented flexible units. When in use, the number of stacked segments can be selected according to actual needs to control the length of the entire flexible manipulator. The length adjustment design is very simple; It is designed to be composed of multiple telescopic modules arranged in a ring, and the telescopic modules and the four isosceles trapezoidal pieces that make up each telescopic module are hinged, so that multiple traction ropes can be designed according to the needs. When using the traction rope When controlling the shortening of the flexible manipulator, different stretching lengths of different parts of the flexible manipulator can be achieved by controlling the work between different traction ropes, so that the flexible manipulator can bend in different directions, not limited to linear expansion and contraction.

Description of drawings

Fig. 1 is a side view structural schematic diagram of the flexible robot arm of the present invention.

Fig. 2 is a three-dimensional structural schematic diagram of the flexible robotic arm of the present invention without a traction rope.

Fig. 3 is a top structural schematic diagram of the flexible robotic arm of the present invention.

Fig. 4 is a perspective view of the flexible robotic arm of the present invention without a traction rope.

Fig. 5 is a three-dimensional structural schematic diagram of linearly stacked flexible units.

Fig. 6 is a schematic diagram of a three-dimensional structure of a single flexible unit.

Fig. 7 is a schematic diagram of the three-dimensional structure of the telescopic module.

Fig. 8 is a schematic perspective view of the telescopic module in a folded state.

Fig. 9 is a schematic structural view of the first use state of the flexible robotic arm of the present invention.

Fig. 10 is a schematic structural diagram of the second use state of the flexible robotic arm of the present invention.

Figure 11 is a geometric diagram.

Detailed ways

As shown in Figures 1 to 5, a flexible manipulator with positive angle compensation based on origami theory includes several flexible units 1 stacked linearly, and a driving mechanism for driving each flexible unit 1 to expand and contract. In the structure shown in the figure, the flexible unit 1 has 5 sections. When in use, the number of stacked sections can be selected according to actual needs to control the length of the entire flexible robotic arm, and the length adjustment design is very simple.

As shown in Figures 6 to 8, each flexible unit 1 includes a plurality of telescopic modules 2 arranged in a ring, and each telescopic module 2 includes four isosceles trapezoidal pieces 3, and the sides of the four isosceles trapezoidal pieces 3 are hinged in sequence to form four For the telescopic modules 2 of the truncated pyramid structure, when the multiple telescopic modules 2 of each flexible unit 1 are arranged in a circle, the top surface of the truncated pyramid structure faces the inner center of the ring, and the bottom surface of the truncated pyramid structure deviates from the inner center of the ring. That is, the two waists of the isosceles trapezoidal sheet 3 are hinged with the waists of two adjacent isosceles trapezoidal sheets 3, and the four isosceles trapezoidal sheets 3 enclose a circle. Since the upper and lower bases of such a quadrangular truncated pyramid structure are hollow, the quadrangular pyramid truncated structure deforms after being squeezed in the side direction, and the cross section changes from a square to a rhombus, so that the size in the direction of the force is changed. Compression shortens.

The number of telescopic modules 2 in each flexible unit 1 can be selected according to actual needs. The smaller the number, the rougher the control accuracy of the entire flexible manipulator, and the more the number, the finer the control accuracy of the entire flexible manipulator. Generally, at least 3 telescopic modules 2 are included, for example, each flexible unit 1 may include 3, 4, 6 or 8 telescopic modules 2 .

The adjacent telescopic modules 2 in each section of the flexible unit 1 are hinged by the upper bottom sides of the two isosceles trapezoidal pieces 3 abutted against each other. Generally speaking, the isosceles trapezoidal sheets 3 used by the telescopic modules 2 in each section of the flexible unit 1 are all of the same size and shape, which is more convenient for production and easier to control. Denote the height of the isosceles trapezoidal sheet 3 as h, the upper base as a, and the lower base as b, and each flexible unit 1 includes n telescopic modules, then it satisfies:

When the shape of the isosceles trapezoidal sheet 3 satisfies the above formula, the flexible unit 1 can be stretched to the maximum thickness. If it deviates from the relationship of this formula, when the flexible unit 1 is stretched, it cannot be stretched. to the maximum thickness.

The driving mechanism includes: sequentially passing through at least part of the isosceles trapezoidal sheet 3 in each section of the flexible unit 1, a traction rope 6 that is folded and shortened on at least one side of the flexible unit 1, and a section of the flexible unit 1 that is located at the end. The outer side is a retractable unit for retracting the traction rope 6 . The isosceles trapezoidal sheet 3 is correspondingly provided with a traction hole 11 through which the traction rope 6 passes. A mounting plate 7 is provided on the outer side of a section of the flexible unit 1 located at the rearmost end. The side of the mounting plate 7 facing away from the flexible unit 1 is provided with a retractable unit. Each traction rope 6 is correspondingly provided with a group of retractable units. The retractable unit It includes a take-up reel 8 and a motor 9 for driving the take-up reel 8 to rotate. The mounting plate 7 is provided with an avoidance hole 10 for the traction rope 6 to pass through.

In one embodiment, all the telescopic modules 2 of all flexible units 1 are grouped, and the telescopic modules 2 arranged on the same straight line between adjacent flexible units 1 are grouped and controlled by a traction rope 6 .

In another embodiment, each flexible unit 1 includes an even number of telescopic modules 2, all the telescopic modules 2 of all flexible units 1 are grouped, and the telescopic modules 2 of the same flexible unit 1 are divided into two groups. Each subgroup arranged on the same straight line between the adjacent flexible units 1 is divided into a large group, and is controlled by a traction rope 6 . The structure shown in the figure is such an embodiment. Each flexible unit 1 in the figure includes 8 telescopic modules 2, which are divided into 4 large groups and controlled by 4 traction ropes 6. And, each traction rope 6 passes through adjacent two of the four isosceles trapezoidal sheets 3 of each telescopic module 2 in turn, and when the traction rope 6 passes through two telescopic modules 2 located in the same section of the flexible unit 1, each other After the adjacent isosceles trapezoidal sheet 3, one end passes through the isosceles trapezoidal sheet 3 on one side of the retractable unit in one of the telescopic modules 2, and the other end passes through the other telescopic module 2 away from the retractable unit. The isosceles trapezoidal piece 3 on one side, and then the traction rope passes through the isosceles trapezoidal piece 3 that is adjacent to each other in the two telescopic modules 2 of the two adjacent flexible units 1, and the traction rope 6 as a whole presents a broken line type.

The flexible mechanical arm of the present invention folds each isosceles trapezoidal sheet 3 in the telescopic module 2 through the traction of the traction rope 6, and after folding, the traction rope 6 needs to be released to keep the flexible unit 1 in a stretched state, so as to restore the flexible mechanical arm. Shape, in the case of not setting the corresponding recovery driving structure, the flexible manipulator can be used vertically, relying on gravity to recover.

In a preferred embodiment, as shown in the figure, two isosceles trapezoidal pieces 3 are hinged in a hinge structure, and the hinge structure includes a hinge hole column 4 positioned on the side of the isosceles trapezoidal piece 3 and a hinge hole through the hinge hole. The shaft core 5 of the column 4. In one embodiment, a torsion spring for keeping the flexible unit 1 in a stretched state is also provided in the hinge structure (the torsion spring is not used in the embodiment in the figure), and an automatic recovery torsion spring can be set on the shaft core 5 to Realize the purpose of keeping the flexible unit 1 stretched, like this, in the process of drawing the traction rope 6, as long as the torsional force of the torsion spring is overcome, the flexible unit 1 can be folded and compressed, and after the traction rope 6 is released, the torsion spring will Restoration power can be provided to extend and straighten the flexible robotic arm. When the hinge structure is used, the isosceles trapezoidal sheet 3 and the corresponding hinged hole post 4 can be integrally formed by 3D printing.

When in use, a mounting plate can also be provided on the outer side of a section of flexible unit 1 located at the foremost end (the lower end in FIG. functions, such as some structures for item grabbing, etc.

The calculation and proof of satisfying the formula required for stretching to the maximum thickness is carried out below, taking the vertical arrangement of the flexible unit 1 shown in the figure as an example.

为等腰梯形片与水平面的夹角。θ为伸缩模块2在水平方向上的投影角度。ψ表示竖直方向的等腰梯形片绕中心轴的旋转角度。可以表示为如下表达式：As shown in Figure 11, the projection of the telescopic module 2 in the vertical direction, wherein, I and II represent two horizontal and vertical isosceles trapezoidal sheets; h is the height of the isosceles trapezoidal sheet 3, and a is the isosceles trapezoidal sheet 3 The upper end of the trapezoidal sheet 3, b is the lower end of the isosceles trapezoidal sheet 3. d is the projection of the height of the isosceles trapezoidal plate on the vertical plane. h' is the projection of the height of the isosceles trapezoidal plate on the horizontal plane.

is the angle between the isosceles trapezoid and the horizontal plane. θ is the projection angle of the telescopic module 2 in the horizontal direction. ψ represents the rotation angle of the isosceles trapezoidal sheet in the vertical direction around the central axis. Can be expressed as the following expression:

According to Fig. 11(b), the projection angle of telescopic module 2 in the horizontal direction can be expressed as:

As shown in Figure 11(d), the height of the isosceles trapezoid in the vertical direction is mainly determined by the rotation angle ψ:

Integrating the above formula, we can get the specific expression of the projection angle θ of the telescopic module 2 in the vertical direction as:

As shown in the above formula, θ changes continuously with the change of the rotation angle. The key of the telescopic mechanism 2 in the process of continuous telescopic transformation is to ensure that a section of flexible unit 1 composed of n telescopic modules 2 can be rotated on the circumference in any twisting stage. A circle is formed on , i.e. the sum of the angles is always equal to 360° with respect to the space of the main axis of the flexible manipulator. In order to compensate the angle loss in different torsion stages, it is necessary to design an angle compensation mechanism to compensate the angle.

For the angle compensation mechanism, since the adjacent telescopic modules 2 in each flexible unit 1 are hinged by the upper bottom sides of the two isosceles trapezoidal pieces 3 that are attached to each other, and the upper bottom sides are located inside the entire flexible mechanical arm, so The angle compensation mechanism is an outwardly open compensation mechanism, that is, the angle compensation provided is positive compensation.

The angle change is shown in the following formula, where θ _adaptive is the compensation angle:

nθ+θ _adaptive = 360°

When the telescopic unit is fully stretched (ψ=0°), θ reaches the maximum value. Due to the angle compensation that is open to the outside, the angle can only be compensated positively. At this time, the isosceles trapezoidal sheet located The compensation angle that can be provided by the upper end of the upper end is 0. Therefore, the size of the isosceles trapezoidal tablet should be determined according to the geometric relationship at this time.

Available:

As shown in Figures 9 and 10, the flexible manipulator of the present invention is designed by designing each flexible unit 1 to be composed of a plurality of telescopic modules 2 arranged in a ring, between each telescopic module 2 and the four blocks forming each telescopic module 2 The isosceles trapezoidal pieces 3 are all hinged, so that a plurality of traction ropes 6 can be designed according to the needs. When the traction rope 6 is used to control the shortening of the flexible mechanical arm, the different flexible mechanical arms can be realized by controlling the work between different traction ropes 6. The stretching lengths of the parts are different, so that the flexible robotic arm can bend in different directions, not limited to the stretching in the linear direction.

Claims (8)

1. A flexible mechanical arm with positive angle compensation, characterized in that it includes a number of linearly stacked flexible units, and a drive mechanism for driving each flexible unit to expand and contract; Each flexible unit includes a plurality of telescopic modules arranged in a ring, each telescopic module includes four isosceles trapezoidal pieces, and the sides of the four isosceles trapezoidal pieces are hinged in turn to form a telescopic module with a quadrangular pyramid structure. When the two telescopic modules are arranged in a ring, the top surface of the truncated pyramid structure faces the inner center of the ring, and the bottom surface of the truncated pyramid structure deviates from the inner center of the ring; The isosceles trapezoidal sheets used in the telescopic modules in each flexible unit are all of the same size and shape, and the adjacent telescopic modules in each flexible unit are hinged by the upper bottom sides of the two isosceles trapezoidal sheets that are attached to each other; The height of the waist trapezoidal sheet is expressed as h, the upper base is a, and the lower base is b, and each flexible unit includes n telescopic modules, then it satisfies:

The driving mechanism includes: sequentially passing through at least part of the isosceles trapezoidal sheet in each section of the flexible unit, a traction rope that is folded and shortened on at least one side for pulling the flexible unit, and the outer side of the flexible unit at the end, The retractable unit for retracting the traction rope. 2. The flexible robotic arm according to claim 1, wherein each flexible unit comprises at least 3 telescopic modules. 3. The flexible robotic arm according to claim 2, wherein each flexible unit includes 3, 4, 6 or 8 telescopic modules. 4. The flexible robot arm according to claim 1, characterized in that, a mounting plate is provided on the outer side of a flexible unit located at the rearmost end, and the retractable unit is provided on the side of the mounting plate facing away from the flexible unit, each Each traction rope is correspondingly provided with a set of retractable units, the retractable unit includes a take-up reel, and a motor that drives the take-up reel to rotate, and the mounting plate is provided with an avoidance hole for the traction rope to pass through. 5. The flexible robot arm according to claim 1, wherein all flexible modules of all flexible units are grouped, each flexible module arranged on the same straight line between adjacent flexible units is divided into one group, and is divided into groups by Controlled by a tow rope. 6. The flexible robotic arm according to claim 1, wherein each flexible unit includes an even number of telescopic modules, Group all the telescopic modules of all flexible units, and divide the telescopic modules of the same flexible unit into a group. Each group arranged on the same straight line between adjacent flexible units is divided into a large group, and is controlled by a traction rope. 7. The flexible robotic arm according to claim 1, wherein the two isosceles trapezoidal pieces are hinged in a hinge structure. 8 . The flexible robotic arm according to claim 7 , wherein a torsion spring for keeping the flexible unit in a stretched state is further provided in the hinge structure.

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