CN113733153B - A seven-degree-of-freedom flexible manipulator based on offset cross-axis articulation - Google Patents

Abstract

A seven-degree-of-freedom flexible manipulator based on offset cross-axis articulation. It includes a driving mechanism, an arm segment mechanism, a first connecting rod and a first guide rail; the arm segment mechanism includes first to third joint units; each joint unit has two degrees of freedom in bending, and the entire mechanism has one degree of freedom in movement and six degrees of freedom in movement. bending freedom. Advantages of the present invention: The present invention uses an offset cross joint axis to realize the connection between each joint connecting rod, strengthens the anti-torsion stiffness of the mechanical arm, improves the movement accuracy, and at the same time has a smaller outer diameter, so that the mechanical arm can be well adapted to various Inspection and operation tasks in narrow spaces. A force sensor is used to connect the driving rope, and by sensing the size of the pre-tightening force, the elongation of the driving rope is changed, thereby controlling the bending degree of the flexible manipulator. One drive motor drives two symmetrical drive ropes to achieve a bending degree of freedom of the robotic arm, reducing the number of drive motors and making the flexible robotic arm more compact.

Description

A seven-degree-of-freedom flexible manipulator based on offset cross-axis articulation

Technical field

The invention belongs to the field of robot technology, and in particular relates to a seven-degree-of-freedom flexible manipulator based on an offset cross-axis hinge.

Background technique

Flexible robotic arms are different from traditional rigid-jointed robotic arms. They are usually composed of multiple flexible joints connected in series. They have the advantages of multiple degrees of freedom and flexible movement. They are especially suitable for applications in narrow space environments, such as pipeline inspection and inspection in complex boxes. , aircraft engine on-wing inspection and maintenance, etc.

At present, the joints of flexible manipulators generally use cross universal hinges, spherical hinge structures or purely flexible material support structures. There are problems such as complex joint structures, large outer diameters, and low torsional stiffness, which greatly limits its application scope. In addition, rope-driven flexible manipulators generally use one drive motor to drive a rope, which requires many drive motors and makes the drive mechanism more complex.

Contents of the invention

In order to solve the above problems, the object of the present invention is to provide a seven-degree-of-freedom flexible manipulator based on offset cross-axis articulation.

In order to achieve the above object, the invention provides a seven-degree-of-freedom flexible manipulator based on an offset cross-axis hinge, including a driving mechanism, an arm segment mechanism, a first guide rail and a first link;

Wherein, the first guide rail includes a slide rail, a first slide block, a second screw, a first drive motor, a second coupling and a support frame; the first drive motor is fixedly installed on one end of the support frame, and the output shaft passes through The second coupling is connected to one end of the second screw, and the other end of the second screw is rotatably installed on the other end of the support frame; the slide rail is installed on the support frame parallel to the second screw. ;The first slide block is set on the second screw and the bottom surface is installed on the slide rail, so it can reciprocate along the slide rail driven by the first drive motor;

The arm segment mechanism includes a first joint unit, a second joint unit and a third joint unit with identical structures and arranged in sequence; each joint unit includes a head end link, multiple joint links, and multiple offsets. The cross joint shaft, an elastic support rod and four driving ropes; the entire first end connecting rod is a cylindrical structure, with a first center hole formed through the axis center, and a symmetrical depression along the radial direction on the outer part of the rear end surface. There are two first connecting grooves, and the axes of the two first connecting grooves are located in a straight line, and a plurality of symmetrically distributed first guide holes are formed through the parts located outside the first central hole in the axial direction; the joint connecting rod as a whole is The cylindrical structure has a second central hole formed through the center of the axis, and two second connecting grooves are symmetrically recessed on the outer parts of the two end surfaces, and the axes of the two second connecting grooves are located in a straight line, outside the second central hole. A plurality of symmetrically distributed second guide holes are formed through the parts of The joint axis includes an offset central axis and four joint axes; a third central hole is formed through the axis of the offset central axis, and two symmetrically installed parts on both ends of the offset central axis located outside the third central hole The joint axes, and the axes of the two joint axes are located in a straight line, and the axes of the joint axes on the two end faces are perpendicular to each other; the outer parts of the two joint axes on each end face are respectively embedded in the two first connections on the first end connecting rod. groove or two second connecting grooves on the same end face of the joint connecting rod, thereby using the offset cross joint axis to connect the two joint connecting rods or the head end link and the joint connecting rod to each other and forming two axes that are perpendicular to each other. the first rotating pair, and the third center hole is aligned with the first center hole on the head-end link and the second center hole on the joint link, and each first guide hole on the head-end link is aligned with all joints A second guide hole on the connecting rod is aligned; the elastic support rod is disposed through the first center hole of the head end connecting rod, the second center hole of each joint connecting rod and the third center hole of the offset cross joint shaft; four One end of the drive rope is connected to the first link at equal intervals. The two opposite drive ropes form a pair. The other end passes through all the guide holes at the same position on this joint unit and all joint units located on the rear side of this joint unit. Connected to the drive mechanism;

The driving mechanism includes three driving units respectively connected to one joint unit, a first connecting plate, a second connecting plate, a third connecting plate, a circular cone, a second connecting rod, a fourth connecting plate, connecting parts and a central connection. parts; the first connecting plate, the second connecting plate and the third connecting plate are arranged in parallel at intervals and the middle parts are connected to each other using a central connecting piece; the bottom surface of the circular cone is installed in the middle of the top surface of the third connecting disk, and the top surface of the circular cone passes through multiple The second connecting rod is connected to the fourth connecting plate; one end of the connecting component is connected to the side of the central connecting piece, and the other end extends to the outside of the driving mechanism and is fixedly connected to the first slide block on the first guide rail; each drive The unit includes two second drive motors, two first couplings, four first pulleys, two first screws, at least two guide rods, two first force sensors, two second force sensors, Two second slide blocks, four second pulleys and four third pulleys; two second drive motors are symmetrically installed on the bottom edge of the first connecting plate, and the output shaft runs through the first connecting plate; the first coupling Located between the first connecting plate and the second connecting plate; two first screws are arranged symmetrically, one end of each first screw is rotatably installed on the outer part of the third connecting plate, and the other end penetrates the second connecting plate The rear of the disk is connected to the output end of a second drive motor through a first coupling; at least one guide rod is installed near each first screw, and the two ends of the guide rod are respectively installed on the second connecting disk and on the third connecting plate; each second slide block is simultaneously mounted on a first screw and at least one nearby guide rod, so that it can move back and forth along the guide rod; each first force sensor and second force sensor At the same time, they are installed on the bottom and top surfaces of a second slide block; four first pulleys are symmetrically installed on the central connecting piece between the first connecting plate and the second connecting plate; four second pulleys are symmetrically installed on On the circumferential surface of the circular platform; four third pulleys are symmetrically installed on the top edge of the circular platform, and each first pulley is aligned vertically with the installation position of a second pulley and a third pulley respectively; in the arm segment mechanism One driving rope in each pair of driving ropes on each joint unit first passes through the fourth connecting plate, then goes around a third pulley and a second pulley, then passes through the third connecting plate and is connected to a connecting plate of a driving unit. On the second force sensor, another driving rope first passes through the fourth connecting plate, then goes around a third pulley and a second pulley, then passes through the third connecting plate and the second connecting plate, and then goes around a third pulley. One pulley laterally penetrates the central connecting piece, and finally bypasses another symmetrically arranged first pulley and is connected to the first force sensor;

One end of the first connecting rod is connected to the middle part of the top surface of the fourth connecting plate in the driving mechanism, and the other end is connected to the rear end surface of the joint connecting rod at the rear end of the first joint unit in the arm segment mechanism.

The first connecting rod is an elongated hollow rod.

Two symmetrical U-shaped grooves are recessed inward on the middle circumferential surface of the head end connecting rod, and a plurality of first reducers are formed axially through the portion between the first center hole and the first guide hole. Heavy holes to reduce the overall weight of the first link.

A plurality of second weight-reducing holes are formed on the joint connecting rod between the second center hole and the second guide hole in the axial direction, and the middle portions of the two end faces are recessed inward to reduce the weight of the joint connecting rod. Overall weight.

The central connecting piece is a hollow cylindrical structure.

The seven-degree-of-freedom flexible manipulator based on offset cross-axis hinge provided by the present invention has the following advantages:

1. The offset cross joint axis is used to realize the connection between each joint link, which strengthens the anti-torsion stiffness of the flexible robotic arm and improves the movement accuracy of the flexible robotic arm. At the same time, the outer diameter of the flexible robotic arm is smaller, making This flexible robotic arm can be well adapted to various inspection and operation tasks in narrow spaces.

2. A force sensor is used to connect the driving rope, and by sensing the size of the pre-tightening force, the elongation of the driving rope is changed, thereby controlling the bending degree of the flexible robotic arm.

3. One drive motor drives two symmetrical drive ropes to achieve a bending freedom of the robotic arm, reducing the number of drive motors and making the flexible robotic arm more compact.

Description of the drawings

Figure 1 is a schematic structural diagram of a seven-degree-of-freedom flexible manipulator based on an offset cross-axis hinge according to the present invention.

Figure 2 is a schematic structural diagram of a joint unit of the arm segment mechanism of the present invention.

Figure 3 is a schematic structural diagram of the first end link of the middle arm segment mechanism of the present invention.

Figure 4 is a schematic structural diagram of the joint connecting rod of the arm segment mechanism of the present invention.

Figure 5 is a schematic structural diagram of the offset cross joint axis of the middle arm segment mechanism of the present invention.

Figure 6 is a schematic structural diagram of the driving mechanism in the present invention.

Figure 7 is a schematic structural diagram of the first guide rail in the present invention.

Figure 8 is a schematic longitudinal cross-sectional view of the driving mechanism in the present invention.

Detailed ways

The seven-degree-of-freedom flexible manipulator based on the offset cross-axis hinge provided by the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figures 1 to 8, the seven-degree-of-freedom flexible manipulator based on offset cross-axis hinge provided by the present invention includes a driving mechanism 1, an arm segment mechanism 2, a first link 4 and a first guide rail 3;

The first guide rail 3 includes a slide rail 31, a first slide block 32, a second screw 311, a first drive motor 33, a second coupling 34 and a support frame 35; the first drive motor 33 is fixedly installed on At one end of the support frame 35, the output shaft is connected to one end of the second screw 311 through the second coupling 34, and the other end of the second screw 311 is rotatably installed on the other end of the support frame 35; the slide rail 31 It is installed on the support frame 35 in a parallel manner with the second screw 311; the first slider 32 is set on the second screw 311 and the bottom surface is installed on the slide rail 31, so it can be driven along the first drive motor 33. The slide rail 31 moves back and forth;

The arm segment mechanism 2 includes a first joint unit I, a second joint unit II and a third joint unit III which are identical in structure and arranged in sequence; each joint unit includes a head end link 21 and a plurality of joint links. 22. Multiple offset cross joint shafts 23, an elastic support rod 25 and four driving ropes 24; the entire head end link 21 is a cylindrical structure, with a first central hole 212 formed through the axis center. Two first connecting grooves 213 are formed symmetrically in the outer part of the rear end surface along the radial direction, and the axes of the two first connecting grooves 213 are located in a straight line. The part located outside the first central hole 212 is formed with a plurality of axially penetrating grooves 213 . symmetrically distributed first guide holes 211; the joint connecting rod 22 is a cylindrical structure as a whole, with a second central hole 222 formed through the axis, and two second connecting grooves 223 formed symmetrically in the outer parts of both end surfaces, and The axes of the two second connecting grooves 223 are located in a straight line, and a plurality of symmetrically distributed second guide holes 221 are formed through the portion located outside the second central hole 222 in the axial direction; the head end link 21 and the joint link 22 and An offset cross joint shaft 23 is provided between two adjacent joint links 22; each offset cross joint shaft 23 includes an offset central shaft 232 and four joint shafts 231; the axis center of the offset central shaft 232 is A third central hole 233 is formed through it. Two joint shafts 231 are symmetrically installed on both ends of the offset central shaft 232 outside the third central hole 233, and the axes of the two joint shafts 231 are located in a straight line. The axes of the joint shafts 231 on the end faces are perpendicular to each other; the outer parts of the two joint shafts 231 on each end face are respectively embedded in the two first connecting grooves 213 on the head end connecting rod 21 or the two first connecting grooves 213 on the same end face of the joint connecting rod 22. In the second connecting groove 223, the offset cross joint shaft 23 is used to connect the two joint links 22 or the head end link 21 and the joint link 22 to each other and form a first rotating pair 26 with two axes perpendicular to each other. And the third center hole 233 is aligned with the first center hole 212 on the head end link 21 and the second center hole 222 on the joint link 22. At the same time, each first guide hole 211 on the head end link 21 is aligned with A second guide hole 221 on all joint links 22 is aligned; the elastic support rod 25 penetrates the first center hole 212 of the head end link 21, the second center hole 222 of each joint link 22 and the offset cross joint In the third center hole 233 of the shaft 23; one end of the four driving ropes 24 is connected to the first link 21 at equal intervals. The two opposite driving ropes 24 form a pair, and the other end passes through the joint unit and is located on the joint unit. All guide holes at the same position on all joint units on the rear side are connected to the driving mechanism 1;

The driving mechanism 1 includes three driving units respectively connected to one joint unit, a first connecting plate 102, a second connecting plate 104, a third connecting plate 109, a circular cone 110, a second connecting rod 113, and a fourth connecting plate. 114. The connecting part 117 and the central connecting piece 118; the first connecting plate 102, the second connecting plate 104 and the third connecting plate 109 are arranged in parallel at a distance and the middle parts are connected to each other by the central connecting piece 118; the bottom surface of the circular cone 110 is installed on the third connecting plate. The middle part of the top surface of the connecting plate 109 and the top surface of the circular cone 110 are connected to the fourth connecting plate 114 through a plurality of second connecting rods 113; one end of the connecting part 117 is connected to the side of the central connecting piece 118, and the other end extends to the drive The outside of the mechanism 1 is fixedly connected to the first slider 32 on the first guide rail 3; each drive unit includes two second drive motors 101, two first couplings 103, four first pulleys 115, two A first screw 105, at least two guide rods 106, two first force sensors 107, two second force sensors 108, two second sliders 116, four second pulleys 111 and four third pulleys 112; Two second drive motors 101 are symmetrically installed on the bottom edge of the first connection plate 102, and the output shaft penetrates the first connection plate 102; the first coupling 103 is located between the first connection plate 102 and the second connection plate 104. two first screws 105 are arranged symmetrically. One end of each first screw 105 is rotatably installed on the outer part of the third connecting plate 109, and the other end penetrates the second connecting plate 104 and passes through a first connection. The shaft device 103 is connected to the output end of a second drive motor 101; at least one guide rod 106 is installed near each first screw 105, and the two ends of the guide rod 106 are respectively installed on the second connecting plate 104 and the second connecting plate 104. On the three connecting plates 109; each second slider 116 is simultaneously mounted on a first screw 105 and at least one nearby guide rod 106, so that it can move back and forth along the guide rod 106; each first force sensor 107 and the second force sensor 108 are installed on the bottom and top surfaces of a second slide block 116 at the same time; four first pulleys 115 are symmetrically installed on the central connecting piece 118 and are located between the first connection plate 102 and the second connection plate 104 position; four second pulleys 111 are symmetrically installed on the circumferential surface of the circular platform 110; four third pulleys 112 are symmetrically installed on the top edge of the circular platform 110, and each first pulley 115 is connected to a second pulley 111 respectively. It is aligned up and down with the installation position of a third pulley 112; one driving rope 24 of each pair of driving ropes 24 on each joint unit in the arm segment mechanism 2 first passes through the fourth connecting plate 114, and then bypasses a third The pulley 112 and a second pulley 111 then pass through the third connecting plate 109 and are connected to a second force sensor 108 of a driving unit. The other driving rope 24 first passes through the fourth connecting plate 114 and then bypasses a The third pulley 112 and a second pulley 111 then pass through the third connecting plate 109 and the second connecting plate 104 one after another, then bypass a first pulley 115 and laterally penetrate the central connecting member 118, and finally bypass another symmetrically arranged The first pulley 115 is connected to the first force sensor 107;

One end of the first link 4 is connected to the middle of the top surface of the fourth connecting plate 114 in the drive mechanism 1, and the other end is connected to the rear end surface of the joint link 22 at the rear end of the first joint unit I in the arm segment mechanism 2.

The first connecting rod 4 is an elongated hollow rod.

The middle circumferential surface of the head end connecting rod 21 is recessed inward to form two symmetrical U-shaped grooves 214. At the same time, the portion between the first central hole 212 and the first guide hole 211 is formed with multiple grooves axially penetrating through it. A first weight reduction hole 215 is provided to reduce the overall weight of the first connecting rod 21.

A plurality of second weight-reducing holes 224 are formed on the joint connecting rod 22 between the second central hole 222 and the second guide hole 221 along the axial direction. At the same time, the middle portions of the two end surfaces are recessed inward to reduce weight. The overall weight of the joint link 22.

The central connecting piece 118 is a hollow cylindrical structure.

The working principle of the seven-degree-of-freedom flexible manipulator based on the offset cross-axis hinge provided by the present invention is: each second drive motor 101 on the drive mechanism 1 drives the first screw 105 to rotate through the first coupling 103 respectively. , thereby causing the second slider 116 to reciprocate along the guide rod 106, thereby driving two symmetrical drive ropes 24 to achieve a bending freedom of a joint unit; one end of a drive rope 24 is connected to the joint unit in the arm segment mechanism 2 on the first end connecting rod 21, the other end is connected to the first force sensor 107 of the driving unit in the driving mechanism 1, one end of the other symmetrical driving rope 24 is connected to the second force sensor 108 of the driving unit, and the other end is connected to to the first link 21 of the joint unit in the arm segment structure 2; the preload force can be sensed through the force sensor, thereby changing the elongation of the drive rope 24 to drive the bending degree of the flexible robotic arm; each drive unit only needs Driven by two second drive motors 101, the six degrees of freedom of bending of the arm segment mechanism 2 are finally realized through the six second drive motors 101, thereby achieving the purpose of controlling the end position of the flexible manipulator; in addition, the first drive motor can be used to 33 drives the driving mechanism 1 and the arm segment mechanism 2 to slide on the first guide rail 3 to realize the freedom of movement of the entire flexible robotic arm; the flexible robotic arm has a total of six degrees of freedom in bending and one degree of freedom in movement, for a total of seven degrees of freedom. ; This robotic arm has the advantages of flexible movement, high compliance, small outer diameter, less drive required, and high torsional rigidity, and can be well adapted to various inspection and operation tasks in narrow spaces.

Claims (5)

1. A seven-degree-of-freedom flexible manipulator based on an offset cross-axis hinge, characterized in that: the seven-degree-of-freedom flexible manipulator based on an offset cross-axis hinge includes a drive mechanism (1) and an arm segment mechanism (2) , the first guide rail (3) and the first connecting rod (4); Wherein, the first guide rail (3) includes a slide rail (31), a first slide block (32), a second screw (311), a first drive motor (33), a second coupling (34) and Support frame (35); the first drive motor (33) is fixedly installed on one end of the support frame (35), and the output shaft is connected to one end of the second screw (311) through the second coupling (34). The other end of the screw (311) is rotatably installed on the other end of the support frame (35); the slide rail (31) is installed on the support frame (35) in a parallel manner with the second screw (311); A slide block (32) is sleeved on the second lead screw (311) and the bottom surface is installed on the slide rail (31), so it can reciprocate along the slide rail (31) driven by the first drive motor (33); The arm segment mechanism (2) includes a first joint unit (Ⅰ), a second joint unit (Ⅱ) and a third joint unit (Ⅲ) with the same structure and arranged in sequence; each joint unit includes a head-end link. Rod (21), multiple joint connecting rods (22), multiple offset cross joint shafts (23), an elastic support rod (25) and four driving ropes (24); the head end connecting rod (21) The whole body is a cylindrical structure, with a first central hole (212) formed through the axis, and two first connecting grooves (213) formed radially symmetrically on the outer part of the rear end surface, and the two first connecting grooves The axis of (213) is located in a straight line, and a plurality of symmetrically distributed first guide holes (211) are formed through the portion located outside the first central hole (212) in the axial direction; the joint connecting rod (22) as a whole is cylindrical. structure, a second central hole (222) is formed through the axis, two second connecting grooves (223) are formed symmetrically in the outer parts of both end faces, and the axes of the two second connecting grooves (223) are located in a straight line , a plurality of symmetrically distributed second guide holes (221) are formed in the outer part of the second central hole (222) along the axial direction; the head end link (21) and the joint link (22) and the two adjacent An offset cross joint axis (23) is provided between the joint connecting rods (22); each offset cross joint axis (23) includes an offset center axis (232) and four joint axes (231); the offset center A third central hole (233) is formed through the axis center of the shaft (232), and two joint shafts (231) are symmetrically installed on the two end surfaces of the offset central shaft (232) outside the third central hole (233). ), and the axes of the two joint shafts (231) are located in a straight line, and the axes of the joint shafts (231) on the two end faces are perpendicular to each other; the outer parts of the two joint shafts (231) on each end face are respectively embedded in the head end connection into the two first connecting grooves (213) on the rod (21) or the two second connecting grooves (223) on the same end face of the joint connecting rod (22), thereby using the offset cross joint shaft (23) to connect the two A joint connecting rod (22) or a first end connecting rod (21) and the joint connecting rod (22) are connected to each other and form a first rotating pair (26) with two axes perpendicular to each other, and the third center hole (233) is connected to the above-mentioned The first center hole (212) on the head end link (21) and the second center hole (222) on the joint link (22) are aligned, and each first guide hole on the head end link (21) (211) is aligned with a second guide hole (221) on all joint links (22); the elastic support rod (25) penetrates the first center hole (212) of the head end link (21), each joint In the second center hole (222) of the connecting rod (22) and the third center hole (233) of the offset cross joint shaft (23); one end of the four driving ropes (24) is connected to the first end connecting rod (21) at equal intervals. ), two opposite driving ropes (24) form a pair, and the other end is connected to the driving mechanism (1) after passing through all the guide holes at the same position on this joint unit and all joint units located on the rear side of this joint unit. ; The driving mechanism (1) includes three driving units respectively connected to one joint unit, a first connecting plate (102), a second connecting plate (104), a third connecting plate (109), a circular cone (110), The second connecting rod (113), the fourth connecting plate (114), the connecting part (117) and the central connecting piece (118); the first connecting plate (102), the second connecting plate (104) and the third connecting plate ( 109) are arranged in parallel at intervals and the middle parts are connected to each other using the central connector (118); the bottom surface of the circular cone (110) is installed in the middle of the top surface of the third connecting plate (109), and the top surface of the circular cone (110) passes through multiple second The connecting rod (113) is connected to the fourth connecting plate (114); one end of the connecting component (117) is connected to the side of the central connecting piece (118), and the other end extends to the outside of the driving mechanism (1) and is connected with the first The first slide block (32) on the guide rail (3) is fixedly connected; each drive unit includes two second drive motors (101), two first couplings (103), and four first pulleys (115) , two first screws (105), at least two guide rods (106), two first force sensors (107), two second force sensors (108), two second sliders (116), Four second pulleys (111) and four third pulleys (112); two second drive motors (101) are symmetrically installed on the bottom edge of the first connecting plate (102), and the output shaft passes through the first connecting plate (102). 102); the first coupling (103) is located between the first connecting plate (102) and the second connecting plate (104); the two first screws (105) are symmetrically arranged, each first screw (105) ) is rotatably installed on the outer part of the third connecting plate (109), and the other end penetrates the second connecting plate (104) and connects to a second driving motor (101) through a first coupling (103) ) is connected to the output end of each first screw (105); at least one guide rod (106) is installed near each first screw (105), and the two ends of the guide rod (106) are installed on the second connection plate (104) and the third connection plate respectively. on the plate (109); each second slider (116) is simultaneously mounted on a first screw (105) and at least one nearby guide rod (106), and therefore can move reciprocally along the guide rod (106) ; Each first force sensor (107) and second force sensor (108) are installed on the bottom and top surfaces of a second slide block (116) at the same time; four first pulleys (115) are symmetrically installed on the central connector (118) is located between the first connecting plate (102) and the second connecting plate (104); four second pulleys (111) are symmetrically installed on the circumferential surface of the circular platform (110); four third pulleys (112) is symmetrically installed on the top edge of the circular cone (110), and each first pulley (115) is aligned vertically with the installation position of a second pulley (111) and a third pulley (112) respectively; One driving rope (24) of each pair of driving ropes (24) on each joint unit in the arm segment mechanism (2) first passes through the fourth connecting plate (114), and then bypasses a third pulley (112) and a The second pulley (111) then passes through the third connecting plate (109) and is connected to a second force sensor (108) of a driving unit. The other driving rope (24) first passes through the fourth connecting plate (114). ), then bypass a third pulley (112) and a second pulley (111), then pass through the third connecting plate (109) and the second connecting plate (104), and then bypass a first pulley (115 ) laterally passes through the central connecting member (118), and finally bypasses another symmetrically arranged first pulley (115) and is connected to the first force sensor (107); One end of the first connecting rod (4) is connected to the middle part of the top surface of the fourth connecting plate (114) in the driving mechanism (1), and the other end is connected to the joint at the rear end of the first joint unit (I) in the arm segment mechanism (2). On the rear end surface of connecting rod (22). 2. The seven-degree-of-freedom flexible manipulator based on the offset cross-axis hinge according to claim 1, characterized in that: the first connecting rod (4) is an elongated hollow rod. 3. The seven-degree-of-freedom flexible manipulator based on the offset cross-axis hinge according to claim 1, characterized in that: the middle circumferential surface of the head end link (21) is recessed inward to form two symmetrical U-shaped groove (214), and a plurality of first weight-reducing holes (215) are formed axially through the portion between the first central hole (212) and the first guide hole (211) to reduce the weight of the head-end connection. The overall weight of the rod (21). 4. The seven-degree-of-freedom flexible manipulator based on the offset cross-axis hinge according to claim 1, characterized in that: the joint connecting rod (22) is located on the second center hole (222) and the second guide hole (222). A plurality of second weight-reducing holes (224) are formed in the portion between 221) along the axial direction, and the middle portions of the two end faces are recessed inward to reduce the overall weight of the joint connecting rod (22). 5. The seven-degree-of-freedom flexible manipulator based on offset cross-axis hinge according to claim 1, characterized in that: the central connecting piece (118) is a hollow cylindrical structure.