Under-actuated metamorphic manipulator integrating grabbing and pressing operations

Abstract

The invention discloses an under-actuated metamorphic manipulator integrating grasping and pressing operations, which comprises a palm bracket, at least two under-actuated grasping fingers, a rigid pressing single finger and a driving mechanism, and is characterized in that the under-actuated grasping fingers and the rigid pressing single finger are arranged on the palm bracket. The main functions of the manipulator include self-adaptive enveloping and grabbing of objects in different shapes and execution of operations such as switch and button pressing, the enveloping and grabbing function is mainly completed by the under-actuated grabbing finger, and the rigid pressing single finger can also play a role in auxiliary clamping; in the pressing function, force is output by a mechanical arm connected with the manipulator, and pressure is applied to a target through a rigid pressing single finger. The under-actuated metamorphic manipulator integrating grabbing and pressing operation is used for fine operation in the flammable and explosive environment, the grabbing adaptability and the structural rigidity are both considered, multiple kinds of grabbing and pressing operation can be conducted, and the under-actuated metamorphic manipulator has the advantages of being light in weight, high in integration level and large in output force.

Description

Technical Field

[0001] The present invention belongs to the technical field of robotics, and particularly relates to an underactuated metamorphic manipulator integrating grasping and pressing operations. Background Art

[0002] Equipment operating in flammable and explosive places such as hazardous chemical product production plants and underground spaces needs to meet certain explosion-proof requirements. Existing explosion-proof designs generally isolate internal circuits and mechanical components prone to friction by using protective enclosures, or reduce the voltage so that the possible generated electric sparks are not sufficient to ignite. As production safety is a key point in the industrial production process, the requirements for the explosion-proof design of robots are constantly increasing, while there is relatively little research on existing explosion-proof manipulators, and there is still a large room for development.

[0003] The adaptive grasping of a manipulator for objects with complex contours is one of the popular research directions in the field of robotics. Manipulators designed through bionic design can often improve dexterity and adaptability. However, more anthropomorphic manipulators will increase the number of joints, and drive sources need to be added at each joint, resulting in an increase in overall mass, a more complex structure, and a reduction in the output ability, execution accuracy, and reliability of the manipulator.

[0004] The manipulator designed based on the principle of metamorphic cells adopts an underactuated driving strategy, which reduces the mass of the manipulator while ensuring grasping adaptability, and has a compact structure and high reliability. However, there are also certain problems with the underactuated mechanism. For example, there is chaotic motion, the motion trajectory of the mechanism is uncertain, it is easy to generate motion singularities, and the stability is insufficient; the variable stiffness structure can only provide stiffness in the grasping direction and cannot perform operations such as pressing. For example, in the patent with the patent number CN109807915A and the patent name "An Underactuated Bionic Manipulator with Variable Stiffness Based on the Principle of Metamorphic Cells", an underactuated manipulator composed of metamorphic finger mechanisms with the same structure is disclosed. A single finger is composed of a planar six-bar mechanism and a rocker-slider mechanism in series, with 2 degrees of freedom. When the finger bends to grasp, the middle link is fixed after contacting the object, and the degree of freedom of the mechanism is reduced to 1, so as to adapt to the grasping of objects with different shapes. The power is transmitted to the slider part through a lead screw, and then the link is driven to move. However, in this scheme, the underactuated structure has redundant degrees of freedom and insufficient self-rigidity, and can only output force in a specific direction and cannot perform operations such as pressing. Another example is the manipulator disclosed in the patent with the patent number CN115070813A and the patent name "A New Type of Intelligent Dexterous Hand with a Planar Eight-Bar Metamorphic Mechanism". This manipulator is composed of three fingers with the same structure arranged in a triangle. Among them, a single finger is composed of a planar six-bar mechanism and a slide rail mechanism in series, with a total of 2 degrees of freedom. Each finger is driven by two independent drivers. The motor at the finger root drives the bending of the six-bar mechanism on the finger, and the linear motor on the palm drives the displacement of the whole finger on the slide rail. However, in this scheme, each mechanical finger requires two driving components to control the translation and bending of the finger respectively, resulting in an increase in the mass of the manipulator, a complex structure, and a large control difficulty. Another example is the mechanical finger based on the metamorphic mechanism disclosed in the patent with the patent number CN115625726A and the patent name "A Metamorphic Mechanism, Mechanical Finger and Mechanical Dexterous Hand". Its characteristic is that the linear motor of the driving rod is an equivalent cam mechanism. When the finger root does not contact the grasped object, there is no relative displacement between the fingertip and the finger root, and they rotate together around the hinge at the finger root; after the finger root contacts the object, the driving force of the motor is transmitted to the hinge at the fingertip, driving the rotation of the fingertip part. However, in this scheme, the mechanical finger adopts an equivalent cam design, and the connection part wears seriously, and there may be impacts, which cannot meet the requirements of explosion-proof design.

[0005] Therefore, how to provide an explosion-proof manipulator that can take into account grasping adaptability and structural rigidity and perform various operations such as grasping and pressing is a problem to be solved. Summary of the Invention

[0006] The main purpose of the present invention is to provide an underactuated metamorphic manipulator that integrates grasping and pressing operations, so as to overcome the deficiencies of the prior art.

[0007] To achieve the aforementioned invention objectives, the technical solutions adopted by the present invention include: An underactuated metamorphic manipulator integrating grasping and pressing operations, comprising:

[0008] A palm frame, which includes at least one finger fixing part and a thumb fixing part;

[0009] At least two underactuated grasping fingers, whose ends are hinged to the finger fixing parts;

[0010] A rigid pressing single finger, whose end is hinged to the thumb fixing part;

[0011] A driving mechanism, which includes a driving connection component. The underactuated grasping fingers are connected to a distal driving source through the driving connection component, and the rigid pressing single finger is output with force by a robotic arm connected to the manipulator;

[0012] The underactuated grasping fingers perform adaptive enveloping grasping on the target under the driving action of the driving connection component. At the same time, the rigid pressing single finger assists the underactuated grasping fingers to clamp the target under the driving of the output force of the robotic arm; and the rigid pressing single finger performs rigid pressing on the target under the driving of the output force of the robotic arm.

[0013] In a preferred embodiment, the palm frame includes a first finger fixing part and a second finger fixing part. The manipulator includes a first underactuated grasping finger and a second underactuated grasping finger with the same structure. The ends of the first underactuated grasping finger and the second underactuated grasping finger are respectively hinged to the first finger fixing part and the second finger fixing part.

[0014] In a preferred embodiment, the underactuated grasping finger has two degrees of freedom and includes a finger mechanism composed of multiple hinged connecting rods, a flexible fingertip, and a flexible finger pad. The flexible fingertip is arranged at the top of the finger mechanism, and the flexible finger pad is arranged on the inner side of the finger mechanism near the end.

[0015] In a preferred embodiment, the finger mechanism includes a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a fifth connecting rod, and a sixth connecting rod. One end of the first connecting rod is connected to the flexible fingertip, and the other end is hinged to one end of the third connecting rod. One end of the second connecting rod is hinged to the middle of the first connecting rod, and the other end is hinged to one end of the fifth connecting rod. The other end of the third connecting rod is hinged to one end of the sixth connecting rod. One end of the fourth connecting rod is hinged to the middle of the second connecting rod, and the other end is hinged to the finger fixing part. Moreover, the fourth connecting rod is connected to the driving connection assembly and serves as the driving rod of the finger mechanism. The other end of the fifth connecting rod is hinged to the middle of the sixth connecting rod, and the other end of the sixth connecting rod is hinged to the finger fixing part. The flexible finger pad is arranged inside the sixth connecting rod.

[0016] In a preferred embodiment, when the underactuated grasping finger envelopes the grasping target, the whole finger mechanism bends around the hinge joint with the finger fixing part until the flexible finger pad contacts the target. The sixth connecting rod is fixed and the finger mechanism undergoes metamorphosis, and the degree of freedom is reduced to 1. The fourth connecting rod transmits torque to the first connecting rod through the second connecting rod, causing the first connecting rod to rotate and drive the flexible fingertip to bend towards the target until the main target is enveloped and grasped.

[0017] In a preferred embodiment, a torsion spring is further arranged at the hinge joint between the second connecting rod and the fifth connecting rod.

[0018] In a preferred embodiment, the driving connection assembly includes a driving rope connected to the driving source and at least one set of pulleys arranged on the palm bracket. The driving rope bypasses the pulley and the hinge joint between the fourth connecting rod and the finger fixing part.

[0019] In a preferred embodiment, the rigid pressing single finger is an integrally formed rigid body. One end of it is hinged to the thumb fixing part of the palm bracket, and the other end forms a pressing end in the shape of a thumb fingertip.

[0020] In a preferred embodiment, when the rigid pressing single finger performs a pressing operation, after the rigid pressing single finger is fully extended, self-locking is generated through the slope of the contact surface with the palm bracket, and the pressure generated by the pressing is directly transmitted to the palm frame through the rigid pressing single finger and offset by the output force of the robotic arm.

[0021] In a preferred embodiment, the driving sources of the underactuated grasping finger and the rigid pressing single finger are both arranged inside the robotic arm, and respectively transmit motion to the underactuated grasping finger and the rigid pressing single finger through the driving rope.

[0022] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0023] 1. The present invention provides a multi-functional manipulator structure integrating grasping and pressing functions, which can simultaneously meet the requirements of high adaptability and high stiffness output of the manipulator, has a high level of integration, good grasping adaptability, high motion stability, and strong output ability, and can be used as an industrial manipulator; moreover, the manipulator of the present invention adopts a remote drive method with rope drive, and the drive motor can be sealed and stored in a remote safe environment, which can meet the explosion-proof requirements in flammable and explosive dangerous environments and is used for risk removal operations in special environments such as factories and underground.

[0024] 2. The present invention sets a torsion spring at the hinge between the connecting rods, which can solve the problem of chaotic motion (i.e., the irregular motion of the underactuated link) generated by the underactuation of the existing manipulator. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 is a three-dimensional schematic diagram of the underactuated metamorphic manipulator integrating grasping and pressing operations of the present invention;

[0027] Figure 2a is a three-dimensional structural schematic diagram of the underactuated grasping finger of the present invention;

[0028] Figure 2b is a front view structural schematic diagram of the underactuated grasping finger of the present invention;

[0029] Figure 3 is a schematic diagram of the metamorphic principle of the underactuated grasping finger of the present invention;

[0030] Figure 4 is a schematic diagram of the initial state of the grasping action of the manipulator of the present invention;

[0031] Figure 5 is a schematic diagram of the mechanism metamorphosis after the finger belly of the manipulator contacts an object;

[0032] Figure 6 is a schematic diagram of the state of the manipulator after completely grasping an object;

[0033] Figure 7 is a structural schematic diagram of the rigid pressing single finger of the present invention;

[0034] Figure 8 is a schematic diagram of the principle of the underactuated metamorphic manipulator of the present invention.

[0035] Reference numerals:

[0036] 1. Palm bracket, 11. Thumb fixing part, 12. First finger fixing part, 13. Second finger fixing part, 2. First underactuated grasping finger, 201. Flexible fingertip, 202. First connecting rod, 203. Second connecting rod, 2031. First bending part, 204. Third connecting rod, 205. Fourth connecting rod, 206. Fifth connecting rod, 207. Torsion spring, 208. Flexible finger belly, 209. Sixth connecting rod, 2091. Second bending part, 3. Second underactuated grasping finger, 4. Rigid pressing single finger, 5. Pulley, 6. Driving rope. Detailed implementation manners

[0037] The present invention will be more fully understood by the following detailed implementation manners which should be read in conjunction with the accompanying drawings. Specific embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely exemplary of the present invention, and the present invention can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but only as a basis for the claims and as a representative basis for teaching those skilled in the art to employ the present invention in any appropriate detailed embodiment in different ways.

[0038] As Figures 1 to 6 shown, an underactuated metamorphic manipulator integrating grasping and pressing operations disclosed by the present invention mainly includes a palm bracket 1, at least one underactuated grasping finger, a rigid pressing single finger 4 and a driving mechanism, wherein the underactuated grasping finger and the rigid pressing single finger 4 are arranged on the palm bracket 1. The main functions of the manipulator are divided into adaptive envelope grasping of objects with different shapes and performing operations such as pressing switches and buttons. Among them, the envelope grasping function is mainly completed by the underactuated grasping finger, and the rigid pressing single finger 4 can also play an auxiliary clamping role; the pressing function outputs force by a robotic arm (not shown in the figure) connected to the manipulator, and applies pressure to the target through the rigid pressing single finger 4.

[0039] Among them, the palm bracket 1 is shaped like a human palm, and it includes a thumb fixing part 11 for connecting the rigid pressing single finger 4 and at least one finger fixing part for connecting the underactuated grasping finger. In this embodiment, a thumb fixing part 11 and two finger fixing parts are arranged on the palm bracket 1. For the convenience of description, the two finger fixing parts are respectively defined as a first finger fixing part 12 and a second finger fixing part 13.

[0040] The underactuated grasping finger is shaped like a human finger, with its end hinged to the palm bracket 1 and connected to the driving mechanism. Under the power transmission of the driving mechanism, it performs an enveloping grasp on the target. Specifically, in this embodiment, two underactuated grasping fingers with the same structure are provided, corresponding to the two finger fixing parts, and are respectively defined as the first underactuated grasping finger 2 and the second underactuated grasping finger 3. The ends of both are respectively hinged to the first finger fixing part 12 and the second finger fixing part 13. In other extended embodiments, it can also be extended to provide one or more than three underactuated grasping fingers with the same structure, and the present invention does not limit this.

[0041] In this embodiment, each underactuated grasping finger is specifically a planar seven-bar mechanism based on the metamorphic principle with two degrees of freedom, which can achieve an adaptive enveloping grasp on objects of different shapes. It includes a finger mechanism composed of multiple hinged connecting rods, a flexible fingertip 201, and a flexible finger pad 208. Among them, the flexible fingertip 201 is arranged at the top of the finger mechanism, and the flexible finger pad 208 is arranged on the inner side of the finger mechanism near the end. In this embodiment, the fingertip and the finger pad are preferably set to be flexible, so as to better protect the target product. Of course, in other embodiments, the fingertip and the finger pad can also be rigid, and / or, the finger pad is not necessary, that is, the finger pad can be not provided, etc., and the present invention does not limit this.

[0042] In this embodiment, in combination with Figure 2a and Figure 2b 、 Figures 3 to 6As shown in the figure, the finger mechanism is composed of six articulated connecting rods. These six connecting rods and the palm bracket 1 form a planar seven-bar driving mechanism. The six connecting rods are respectively defined as the first connecting rod 202, the second connecting rod 203, the third connecting rod 204, the fourth connecting rod 205, the fifth connecting rod 206, and the sixth connecting rod 209. Among them, one end of the first connecting rod 202 is connected to the flexible fingertip 201, and the other end is articulated with one end of the third connecting rod 204; one end of the second connecting rod 203 is articulated with the middle part of the first connecting rod 202, and the other end is articulated with one end of the fifth connecting rod 206. Specifically, in this embodiment, the second connecting rod 203 has a first bending part 2031; the other end of the third connecting rod 204 is articulated with one end of the sixth connecting rod 209; one end of the fourth connecting rod 205 is articulated with the middle part of the second connecting rod 203 (specifically, with the first bending part 2031 of the second connecting rod 203), and the other end is articulated with the finger fixing part; the other end of the fifth connecting rod 206 is articulated with the middle part of the sixth connecting rod 209; the other end of the sixth connecting rod 209 is articulated with the finger fixing part. Specifically, in this embodiment, the sixth connecting rod 209 has a second bending part 2091, and the other end of the fifth connecting rod 206 is specifically articulated with this second bending part 2091 of the sixth connecting rod 209. In addition, in this embodiment, the flexible finger pad 208 is specifically arranged on the inner side of the sixth connecting rod 209. And the fourth connecting rod 205 of the finger mechanism is connected to the driving connection component and serves as the driving rod of the entire finger mechanism. The present invention designs a metamorphic mechanism composed of 6 connecting rods and a frame, and its configuration can be approximately regarded as two 5-bar mechanisms in series, among which 3 rods are common rods. The schematic diagram is as shown in Figure 8 shown. Compared with the existing metamorphic mechanism, there are more common rods. And the present invention improves the stability of the underactuated mechanism by increasing the coincidence degree between the two connecting rod groups.

[0043] The movement of the underactuated grasping finger is divided into two stages. The first stage is that under the drive of the driving mechanism, the entire underactuated grasping finger bends around the articulated part articulated with the palm bracket 1 until the flexible finger pad 208 contacts and fits with the object to be grasped (not shown in the figure). After that, the sixth connecting rod 209 is fixed, and the finger mechanism undergoes metamorphosis, and the degree of freedom is reduced to 1, as shown in Figure 4 shown; the second stage is that the fourth connecting rod 205 transmits torque through the second connecting rod 203, causing the first connecting rod 202 to make a rotational movement, driving the flexible fingertip 201 to continuously bend and finally contact and envelope the object to be grasped, as shown in Figure 5 and Figure 6 shown.

[0044] In addition, preferably, in order to prevent chaotic motion of the mechanism in the underactuated state in the first stage, that is, the irregular motion of the underactuated connecting rod, the present invention further provides a torsion spring 207 at the hinge joint between the second connecting rod 203 and the fifth connecting rod 206, which can play a stabilizing role when the finger mechanism is displaced. It should be noted that even if the actuator is locked in the underactuated mechanism, there will still be free movement of the connecting rod, so during the movement of the manipulator, the mechanical finger will uncontrollably extend or contract, which is called chaotic motion. If the mechanism is caused to fall into a singular position, the normal motion will fail. In the present invention, the underactuated situation occurs in the first stage of the movement, that is, in the 5-bar mechanism composed of the fourth connecting rod 205, the second connecting rod 203, the fifth connecting rod 206, the sixth connecting rod 209, and the palm bracket 1, and the number of degrees of freedom lacking is 1. Therefore, only one torsion spring can be arranged at the hinge joint between the above-mentioned connecting rods. Since the sixth connecting rod 209 is the output rod and the fourth connecting rod 205 is the driving rod, it cannot be arranged at the connection with the palm bracket 1; during the movement process, the relative rotation stroke between the fourth connecting rod 205 and the second connecting rod 203 is small. If a torsion spring is arranged at the first bending portion 2031, the chaotic motion problem cannot be completely solved. The hinge joint between the fifth connecting rod 206 and the sixth connecting rod 209 can also be used as an alternative installation point. The specific selection is affected by the lengths of each rod. In the embodiment given in the present invention, the rotation stroke between the second connecting rod 203 and the fifth connecting rod 206 includes a pole point, which may cause motion singularity. Arranging a torsion spring here can automatically reset the hinge of the first bending portion 2031 when the manipulator opens, preventing the mechanism from stagnating in the singular position.

[0045] The end of the rigid pressing single finger 4 is hinged to the above-mentioned thumb fixing portion 11, and its output force is provided by the robotic arm connected to the manipulator. In this embodiment, in combination with Figure 7 As shown, the rigid pressing single finger 4 is an integrally formed rigid body, one end of which is hinged to the thumb fixing portion 11 of the palm bracket 1, and the other end forms a pressing end in the shape of a thumb fingertip. The rigid pressing single finger 4 is hinged at the corresponding position of the palm bracket 1. When assisting in grasping, the driving force is transmitted by the driving rope. When a pressing action needs to be performed, it is pulled to the open state by the driving rope, and then the pressing driving force is directly provided by the manipulator. The contact surface between the bottom of the finger and the frame is not completely perpendicular to the pressure direction, forming self-locking. Compared with the existing manipulator with redundant degrees of freedom, insufficient self-rigidity, and only being able to output forces in a specific direction and unable to perform operations such as pressing, the present invention uses a rigid pressing single finger to apply a rigid pressure to the target, realizing operations such as pressing switches and buttons on the target object. When the rigid pressing single finger 4 performs a pressing operation, after the rigid pressing single finger 4 is fully extended, self-locking is generated through the slope of the contact surface with the palm bracket. The pressure generated by the pressing is directly transmitted to the palm frame 1 by the rigid pressing single finger 4 and offset by the output force of the robotic arm, avoiding the burden on the driving rope.

[0046] The driving mechanism specifically includes a driving connection component. The underactuated grasping finger is connected to a driving source (not shown in the figure) at the distal end through this driving connection component. In this embodiment, the driving connection component specifically includes a driving rope 6 connected to the driving source and at least one set of pulleys 5 arranged on the palm bracket 1. Preferably, multiple sets of pulleys 5 are arranged to guide the driving rope 6 and reduce the wear of the driving rope 6. The driving rope 6 bypasses the pulleys 5 and the hinge points of the fourth connecting rod 5 and the finger fixing part. Considering the requirements of explosion-proof design, the driving sources of the underactuated grasping finger and the rigid pressing single finger 4 in the present invention are both designed inside the distal manipulator. Compared with the driving mechanism of the existing manipulator directly arranged on the manipulator, the driving source of the manipulator in the present invention is arranged at the distal end, and a distal driving method using rope drive is specifically adopted. The driving source (such as a driving motor) can be sealed and stored in a safe environment at the distal end (such as inside the manipulator arm), which can meet the explosion-proof requirements in flammable and explosive dangerous environments and is used for danger elimination operations in special environments such as factories and underground. Moreover, the weight of the manipulator is reduced, and the manipulator has the advantages of simple structure, light weight, and strong load capacity.

[0047] The underactuated metamorphic manipulator integrating grasping and pressing operations provided by the embodiment of the present invention has the following advantages: 1. The present invention provides a multifunctional manipulator structure integrating grasping and pressing functions, which can simultaneously meet the requirements of high adaptability and high stiffness output of the manipulator, has a high integration level, good grasping adaptability, high motion stability, and strong output ability, and can be used as an industrial manipulator; moreover, the manipulator of the present invention adopts a distal driving method using rope drive, and the driving motor can be sealed and stored in a safe environment at the distal end, which can meet the explosion-proof requirements in flammable and explosive dangerous environments and is used for danger elimination operations in special environments such as factories and underground. 2. The present invention sets torsion springs at the hinge points between the connecting rods, which can solve the problem of chaotic motion (i.e., the irregular motion of the underactuated connecting rod) generated by the underactuation of the existing manipulator.

[0048] All aspects, embodiments, features, and examples of the present invention should be considered illustrative in all respects and are not intended to limit the present invention. The scope of the present invention is only defined by the claims. Without departing from the spirit and scope of the claimed present invention, those skilled in the art will understand other embodiments, modifications, and uses.

[0049] In the present invention, the use of titles and chapters does not mean limiting the present invention; each chapter can be applied to any aspect, embodiment, or feature of the present invention.

Claims

1. An underactuated metamorphic manipulator integrating grasping and pressing operations, characterized in that: The manipulator comprises: A palm frame including at least one finger fixing portion and a thumb fixing portion; at least two underactuated gripping fingers, distal ends of which are hinged to the finger fixing portion; A rigid pressing single finger, the distal end of which is hinged to the thumb fixing portion; A driving mechanism, comprising a driving connection assembly, through which the underactuated grasping finger is connected to a driving source at a remote end, and the rigid pressing single finger outputs force from a mechanical arm connected to the mechanical hand; The underactuated grasping finger performs adaptive envelope grasping on the target under the driving action of the driving connection component, and the rigid pressing finger assists the underactuated grasping finger in clamping the target under the driving force of the robotic arm output; and the rigid pressing finger rigidly presses the target under the driving force of the robotic arm output.

2. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 1, characterized in that: The palm frame includes a first finger fixing portion and a second finger fixing portion, and the manipulator includes a first under-actuated grasping finger and a second under-actuated grasping finger with the same structure, and the ends of the first under-actuated grasping finger and the second under-actuated grasping finger are respectively hinged to the first finger fixing portion and the second finger fixing portion.

3. An underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 1 or 2, characterized in that: The underactuated grasping finger has two degrees of freedom, and includes a finger mechanism composed of multiple hinged connecting rods, a flexible fingertip and a flexible finger pulp. The flexible fingertip is arranged at the top of the finger mechanism, and the flexible finger pulp is arranged on the inner side of the finger mechanism near the end.

4. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 3, characterized in that: The finger mechanism includes a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a fifth connecting rod and a sixth connecting rod, one end of the first connecting rod is connected to the flexible fingertip, and the other end is hinged to one end of the third connecting rod, one end of the second connecting rod is hinged to the middle part of the first connecting rod, and the other end is hinged to one end of the fifth connecting rod, the other end of the third connecting rod is hinged to one end of the sixth connecting rod, one end of the fourth connecting rod is hinged to the middle part of the second connecting rod, and the other end is hinged to the finger fixing part, and the fourth connecting rod is connected to the driving connection assembly as a driving rod of the finger mechanism, the other end of the fifth connecting rod is hinged to the middle part of the sixth connecting rod, and the other end of the sixth connecting rod is hinged to the finger fixing part, and the flexible fingertip is arranged on the inner side of the sixth connecting rod.

5. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 4, characterized in that: When the under-actuated grasping finger envelopes and grasps the target, the finger mechanism as a whole bends around the hinge with the finger fixing part until the flexible fingertip contacts the target, the sixth connecting rod is fixed and the finger mechanism undergoes cell deformation, the degree of freedom is reduced to 1, and the fourth connecting rod transmits torque to the first connecting rod through the second connecting rod, so that the first connecting rod rotates and drives the flexible fingertip to bend in the direction close to the target until it envelopes and grasps the main target.

6. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 4, characterized in that: A torsion spring is also provided at the hinge between the second connecting rod and the fifth connecting rod.

7. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 1, characterized in that: The drive connection assembly includes a drive rope connected to a drive source and at least one group of pulleys arranged on the palm support, and the drive rope passes around the pulleys and the hinge between the fourth connecting rod and the finger fixing part.

8. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 1, characterized in that: The rigid pressing single finger is an integrally formed rigid body, one end of which is hinged to the thumb fixing portion of the palm support, and the other end forms a pressing end in the shape of a thumb tip.

9. An underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 1 or 8, characterized in that: When the rigid pressing single finger performs a pressing operation, the rigid pressing single finger is fully extended and self-locked by the slope of the contact surface with the palm support. The pressure generated by the pressing is directly transmitted to the palm frame along with the rigid pressing single finger and is offset by the output force of the mechanical arm.

10. The underactuated metamorphic manipulator with integrated grasping and pressing operations according to claim 1, characterized in that: The driving source of the underactuated grasping finger and the driving source of the rigid pressing single finger are both arranged in the robot arm, and both transmit motion to the underactuated grasping finger and the rigid pressing single finger respectively through the driving rope.

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