Multi-loop spherical robot based on Bricard mechanism derivation

Abstract

The invention relates to a mobile robot technology, in particular to a multi-loop spherical robot derived based on a Bricard mechanism, which comprises a first spherical shell, a second spherical shell, a third spherical shell and a fourth spherical shell, a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a fifth connecting rod, a sixth connecting rod, a seventh connecting rod and an eighth connecting rod; a first connecting seat, a second connecting seat, a third connecting seat, a fourth connecting seat, a fifth connecting seat and a sixth connecting seat; the single-degree-of-freedom driven spherical robot is composed of a spherical shell and a driving motor, multiple loops are derived through a Bricard mechanism to be combined with the spherical shell, a new structure of the single-degree-of-freedom driven spherical robot is obtained, and the single-degree-of-freedom driven spherical robot has the movement ability of a rolling gait, a creeping gait and a

Description

TECHNICAL FIELD

[0001] The application relates to mobile robot technology, in particular to a multi-loop spherical robot derived from a Bricard mechanism, which can drive the spherical shell to autonomously fold and unfold to realize the motion function of the spherical robot. BACKGROUND

[0002] The spherical robot can realize rapid ground rolling by using a spherical shell, while ensuring stability during motion, and the spherical shell is in point contact with the ground during motion, which can effectively reduce the motion resistance. The Bricard mechanism is composed of six rotating pairs of rigid connecting rods, forming a spatial closed loop chain. Its core feature is over-constrained but movable, meeting the constraint condition of single degree of freedom motion, and can realize flexible spatial motion. By using its characteristics, it can be used as a folding and unfolding driving mechanism of the spherical robot, the external rod is shaped as a special-shaped ball, and a new configuration of a single degree of freedom driving spherical robot is obtained by combining the Bricard mechanism derived multi-loop with the spherical shell, and has the motion ability of rolling gait, peristaltic gait and self-rotation gait.

[0003] Chinese patent CN105690375B discloses a single degree of freedom four-bar mobile robot and a control method thereof, which realizes the straight movement and the deterministic turning movement of the single degree of freedom robot on a plane. SUMMARY

[0004] A multi-loop spherical robot derived from a Bricard mechanism is composed of a first spherical shell, a second spherical shell, a third spherical shell, a fourth spherical shell, a first connecting seat, a second connecting seat, a third connecting seat, a fourth connecting seat, a fifth connecting seat, a sixth connecting seat, a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a fifth connecting rod, a sixth connecting rod, a seventh connecting rod, an eighth connecting rod and a driving motor.

[0005] The connection mode of the parts constituting the mechanism is as follows:

[0006] The single-hole surface and the double-hole surface at the first end of the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod, the sixth connecting rod and the seventh connecting rod are connected through rotating pairs, that is, the single-hole surface at the first end of the first connecting rod is connected to the double-hole surface at the first end of the second connecting rod through a rotating pair, the single-hole surface at the first end of the second connecting rod is connected to the double-hole surface at the first end of the seventh connecting rod through a rotating pair, the single-hole surface at the first end of the seventh connecting rod is connected to the double-hole surface at the first end of the sixth connecting rod through a rotating pair, the single-hole surface at the first end of the sixth connecting rod is connected to the double-hole surface at the first end of the third connecting rod through a rotating pair, the single-hole surface at the first end of the third connecting rod is connected to the double-hole surface at the first end of the fourth connecting rod through a rotating pair, and the single-hole surface at the first end of the fourth connecting rod is connected to the double-hole surface at the first end of the first connecting rod through a rotating pair, forming a Bricard closed loop structure.

[0007] The tail end of the first connecting rod is connected with the first connecting seat through a rotary pair, the tail end of the second connecting rod is connected with the second connecting seat through a rotary pair, the tail end of the third connecting rod is connected with the fourth connecting seat through a rotary pair, the tail end of the fourth connecting rod is connected with the fifth connecting rod through a rotary pair, one end of the fifth connecting rod is connected with the third connecting seat through a rotary pair, the tail end of the sixth connecting rod is connected with the sixth connecting seat through a rotary pair, the tail end of the seventh connecting rod is connected with one end of the eighth connecting rod through a rotary pair, and one end of the eighth connecting rod is connected with the fifth connecting seat through a rotary pair.

[0008] The first spherical shell is fixedly connected with the first connecting seat through bolt holes, the second spherical shell is fixedly connected with the second connecting seat through bolt holes, the third spherical shell is fixedly connected with the third connecting seat and the fourth connecting seat through bolt holes, and the fourth spherical shell is fixedly connected with the fifth connecting seat and the sixth connecting seat through bolt holes, thereby forming a Bennett loop special-shaped structure.

[0009] The body of the driving motor is fixedly connected with the first spherical shell through bolt holes on both sides, and the rotating shaft of the driving motor is fixedly connected with the second spherical shell through bolt holes on both sides.

[0010] The driving motor drives the connected first spherical shell and second spherical shell to move through a rotary pair, the first spherical shell drives the fixedly connected first connecting seat to move, and the second spherical shell drives the fixedly connected second connecting seat to move. The first connecting seat drives the first connecting rod to move through a rotary pair, the second connecting seat drives the second connecting rod to move through a rotary pair, the first connecting rod drives the fourth connecting rod to move through a rotary pair, and the second connecting rod drives the seventh connecting rod to move through a rotary pair. The fourth connecting rod drives the third connecting rod and the fifth connecting rod to move through a rotary pair, the seventh connecting rod drives the sixth connecting rod and the eighth connecting rod to move through a rotary pair. The third connecting rod drives the fourth connecting seat to move through a rotary pair, the fifth connecting rod drives the third connecting seat to move through a rotary pair, the sixth connecting rod drives the sixth connecting seat to move through a rotary pair, and the eighth connecting rod drives the fifth connecting seat to move through a rotary pair. The third connecting seat and the fourth connecting seat drive the fixedly connected third spherical shell to move, and the fifth connecting seat and the sixth connecting seat drive the fixedly connected fourth spherical shell to move.

[0011] The structure of the parts of the mechanism is as follows:

[0012] The first spherical shell has a quarter-spherical shape. Two bolt holes are arranged on the surface of the first spherical shell for fixed connection with the first connecting seat, three through holes are arranged on the surface of the first spherical shell for fixed connection with the front surface of the body of the driving motor, and four through holes are arranged on the surface of the first spherical shell for fixed connection with the back surface of the body of the driving motor.

[0013] The second spherical shell is a quarter of a sphere. Two bolt holes are arranged on the surface of the second spherical shell for fixed connection with the second connecting seat. Five through holes are arranged on the surface of the second spherical shell for fixed connection with one side of the rotating shaft of the driving motor. Five through holes are arranged on the surface of the second spherical shell for fixed connection with the other side of the rotating shaft of the driving motor.

[0014] The third spherical shell is a quarter of a sphere. Two bolt holes are arranged on the surface of the third spherical shell for fixed connection with the third connecting seat. Two bolt holes are arranged on the surface of the third spherical shell for fixed connection with the fourth connecting seat.

[0015] The fourth spherical shell is a quarter of a sphere. Two bolt holes are arranged on the surface of the fourth spherical shell for fixed connection with the fifth connecting seat. Two bolt holes are arranged on the surface of the fourth spherical shell for fixed connection with the sixth connecting seat.

[0016] The first connecting rod is a T-shaped rod. The tail end of the first connecting rod is connected to the first connecting seat through a rotating pair. The head end of the first connecting rod is divided into a single-hole surface and a double-hole surface.

[0017] The second connecting rod is a T-shaped rod. The tail end of the second connecting rod is connected to the second connecting seat through a rotating pair. The head end of the second connecting rod is divided into a single-hole surface and a double-hole surface.

[0018] The third connecting rod is a T-shaped rod. The tail end of the third connecting rod is connected to the fourth connecting seat through a rotating pair. The head end of the third connecting rod is divided into a single-hole surface and a double-hole surface. The seventh connecting rod has the same structure and size as the third connecting rod.

[0019] The fourth connecting rod is a T-shaped rod. The tail end of the fourth connecting rod is connected to the fifth connecting rod through a rotating pair. The head end of the fourth connecting rod is divided into a single-hole surface and a double-hole surface. The sixth connecting rod has the same structure and size as the fourth connecting rod.

[0020] The fifth connecting rod is a long straight rod. One end of the fifth connecting rod is connected to the third connecting seat through a rotating pair. The other end of the fifth connecting rod is connected to the tail end of the fourth connecting rod through a rotating pair. The eighth connecting rod has the same structure and size as the fifth connecting rod.

[0021] The lengths of the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod, the fifth connecting rod, the sixth connecting rod, the seventh connecting rod, and the eighth connecting rod should not exceed the diameter of the spherical shell.

[0022] The first connecting seat, the second connecting seat, the third connecting seat, the fourth connecting seat, the fifth connecting seat, and the sixth connecting seat have the same shape. A large through hole is arranged on the top of each connecting seat for connection with each connecting rod through a rotating pair. Two small through holes are arranged on the bottom of each connecting seat for fixed connection with each spherical shell.

[0023] The multi-loop spherical robot based on the Bricard mechanism is combined with the Bricard mechanism and the Bennett mechanism through the bar and the special-shaped ball shell, compared with the single-loop spherical robot based on the Bennett mechanism, the motion space is expanded, and the folding and unfolding step is larger; compared with the three-loop spherical robot based on the Bennett mechanism, the number of driving motors is reduced, the control is simple, the reliability is high, and the mass of the whole machine is also reduced.

[0024] The multi-loop spherical robot based on the Bricard mechanism has the advantages that the folding and unfolding characteristics of the spatial over-constrained mechanism and the flexible motion performance of the spherical robot are combined, the passive rolling, peristalsis and self-rotation three motion gaits are obtained by changing the folding and unfolding positions and the landing areas, the passive rolling gait can utilize the rolling motion of the spherical shell, has good flexibility, and can realize rapid movement on a flat road, the peristalsis gait has better ground stability, and can realize small-step precise linear motion, and the self-rotation gait can utilize the rotation motion around the central axis to realize the angle change of the motion direction, and the three motion gaits can be switched according to different working requirements to realize the traversal motion of the working area. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Assembly view of the multi-loop spherical robot based on the Bricard mechanism

[0026] Figure 2 Structure views of the first spherical shell, the second spherical shell, the third spherical shell and the fourth spherical shell, wherein (a) is a structure view of the first spherical shell, (b) is a structure view of the second spherical shell, (c) is a structure view of the third spherical shell, and (d) is a structure view of the fourth spherical shell

[0027] Figure 3 Structure views of the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod and the fifth connecting rod, wherein (a) is a structure view of the first connecting rod, (b) is a structure view of the second connecting rod, (c) is a structure view of the third connecting rod, (d) is a structure view of the fourth connecting rod, and (e) is a structure view of the fifth connecting rod

[0028] Figure 4 Structure view of the first connecting seat

[0029] Figure 5 Schematic view of folding and unfolding deformation of the multi-loop spherical robot based on the Bricard mechanism, wherein (a) is a completely folded state, and (b) is a maximum unfolded state

[0030] Figure 6 Schematic view of passive rolling gait of the multi-loop spherical robot based on the Bricard mechanism, wherein (a) is a completely folded state, (b) is an initial unfolded state, (c) is a deformation and dumping position, and (d) is a passive rolling state

[0031] Figure 7 Schematic diagram of the peristaltic gait of the multi-loop spherical robot derived from the Bricard mechanism, wherein (a) is a fully folded state, (b) is a peristaltic expansion, and (c) is a peristaltic contraction

[0032] Figure 8 Schematic diagram of the spinning gait of the multi-loop spherical robot derived from the Bricard mechanism, wherein (a) is a fully folded state, (b) is a spinning expansion, and (c) is a spinning contraction DETAILED DESCRIPTION

[0033] The application will be further described in detail below with reference to the accompanying drawings.

[0034] As shown in the drawings, Figure 1 A multi-loop spherical robot derived from the Bricard mechanism comprises a first spherical shell (1), a second spherical shell (2), a third spherical shell (3), a fourth spherical shell (4), a first connecting rod (5), a second connecting rod (6), a third connecting rod (7), a fourth connecting rod (8), a fifth connecting rod (9), a sixth connecting rod (10), a seventh connecting rod (11), an eighth connecting rod (12), a first connecting seat (13), a second connecting seat (14), a third connecting seat (15), a fourth connecting seat (16), a fifth connecting seat (17), a sixth connecting seat (18), and a driving motor (19).

[0035] Connection mode of parts constituting the mechanism:

[0036] The single-hole surface at the first end of the first connecting rod (5), the second connecting rod (6), the third connecting rod (7), the fourth connecting rod (8), the sixth connecting rod (10), and the seventh connecting rod (11) is connected to the double-hole surface at the first end of the second connecting rod (6) through a revolute pair, i.e., the single-hole surface (5-1) at the first end of the first connecting rod (5) is connected to the double-hole surface (6-1), (6-2) at the first end of the second connecting rod (6) through a revolute pair, the single-hole surface (6-3) at the first end of the second connecting rod (6) is connected to the double-hole surface (11-2), (11-3) at the first end of the seventh connecting rod (11) through a revolute pair, the single-hole surface (11-1) at the first end of the seventh connecting rod (11) is connected to the double-hole surface (10-1), (10-2) at the first end of the sixth connecting rod (10) through a revolute pair, the single-hole surface (10-3) at the first end of the sixth connecting rod (10) is connected to the double-hole surface (7-2), (7-3) at the first end of the third connecting rod (7) through a revolute pair, the single-hole surface (7-1) at the first end of the third connecting rod (7) is connected to the double-hole surface (8-1), (8-2) at the first end of the fourth connecting rod (8) through a revolute pair, and the single-hole surface (8-3) at the first end of the fourth connecting rod (8) is connected to the double-hole surface (5-2), (5-3) at the first end of the first connecting rod (5) through a revolute pair, thereby forming a Bricard closed-loop structure.

[0037] The tail end (5-4), (5-5) of the first connecting rod (5) is connected with the first connecting seat (13) through a rotary pair, the tail end (6-4), (6-5) of the second connecting rod (6) is connected with the second connecting seat (14) through a rotary pair, the tail end (7-4) of the third connecting rod (7) is connected with the fourth connecting seat (16) through a rotary pair, the tail end (8-4) of the fourth connecting rod (8) is connected with one end (9-3) of the fifth connecting rod (9) through a rotary pair, one end (9-1), (9-2) of the fifth connecting rod (9) is connected with the third connecting seat (15) through a rotary pair, the tail end (10-4) of the sixth connecting rod (10) is connected with the sixth connecting seat (18) through a rotary pair, the tail end (11-4) of the seventh connecting rod (11) is connected with one end (12-3) of the eighth connecting rod (12) through a rotary pair, one end (12-1), (12-2) of the eighth connecting rod (12) is connected with the fifth connecting seat (17) through a rotary pair.

[0038] The first spherical shell (1) is fixedly connected with the first connecting seat (13) through bolt holes (1-8), (1-9), the second spherical shell (2) is fixedly connected with the second connecting seat (14) through bolt holes (2-1), (2-2), the third spherical shell (3) is fixedly connected with the third connecting seat (15) and the fourth connecting seat (16) through bolt holes (3-3), (3-4), (3-1), (3-2), and the fourth spherical shell (4) is fixedly connected with the fifth connecting seat (17) and the sixth connecting seat (18) through bolt holes (4-1), (4-2), (4-3), (4-4).

[0039] The body of the driving motor (19) is fixedly connected with the first spherical shell (1) through bolt holes on both sides, and the rotating shaft of the driving motor (19) is fixedly connected with the second spherical shell (2) through bolt holes on both sides.

[0040] The driving motor (19) drives the first spherical shell (1) and the second spherical shell (2) to move through the rotary pair, the first spherical shell (1) drives the fixedly connected first connecting seat (13) to move, and the second spherical shell (2) drives the fixedly connected second connecting seat (14) to move. The first connecting seat (13) drives the first connecting rod (5) to move through the rotary pair, the second connecting seat (14) drives the second connecting rod (6) to move through the rotary pair, the first connecting rod (5) drives the fourth connecting rod (8) to move through the rotary pair, and the second connecting rod (6) drives the seventh connecting rod (11) to move through the rotary pair. The fourth connecting rod (8) drives the third connecting rod (7) and the fifth connecting rod (9) to move through the rotary pair, and the seventh connecting rod (11) drives the sixth connecting rod (10) and the eighth connecting rod (12) to move through the rotary pair. The third connecting rod (7) drives the fourth connecting seat (16) to move through the rotary pair, the fifth connecting rod (9) drives the third connecting seat (15) to move through the rotary pair, the sixth connecting rod (10) drives the sixth connecting seat (18) to move through the rotary pair, and the eighth connecting rod (12) drives the fifth connecting seat (17) to move through the rotary pair. The third connecting seat (15) and the fourth connecting seat (16) drive the fixedly connected third spherical shell (3) to move, and the fifth connecting seat (17) and the sixth connecting seat (18) drive the fixedly connected fourth spherical shell (4) to move.

[0041] The part structure of the mechanism is as follows:

[0042] As shown in Figure 2 a), the first spherical shell (1) is in the shape of a quarter of a sphere. The surface is provided with two bolt holes (1-8), (1-9) for fixedly connecting with the first connecting seat (13), and is provided with three through holes (1-1), (1-1), (1-3) for fixedly connecting with the front face of the body of the driving motor (19), and is further provided with four through holes (1-4), (1-5), (1-6), (1-7) for fixedly connecting with the back face of the body of the driving motor (19).

[0043] As shown in Figure 2 b), the second spherical shell (2) is in the shape of a quarter of a sphere. The surface is provided with two bolt holes (2-1), (2-2) for fixedly connecting with the second connecting seat (14), and is provided with five through holes (2-3), (2-4), (2-5), (2-6), (2-7) for fixedly connecting with one face of the rotating shaft of the driving motor (19), and is further provided with five through holes (2-8), (2-9), (2-10), (2-11), (2-12) for fixedly connecting with the other face of the rotating shaft of the driving motor (19).

[0044] As shown in Figure 2c) The third spherical shell (3) is shown as a quarter of a sphere. Its surface is provided with two bolt holes (3-3), (3-4) for fixed connection with the third connecting seat (15), and two bolt holes (3-1), (3-2) for fixed connection with the fourth connecting seat (16).

[0045] As shown in Figure 2 d) The fourth spherical shell (4) is shown as a quarter of a sphere. Its surface is provided with two bolt holes (4-1), (4-2) for fixed connection with the fifth connecting seat (17), and two bolt holes (4-3), (4-4) for fixed connection with the sixth connecting seat (18).

[0046] As shown in Figure 3 a) The first connecting rod (5) is shown as a T-shaped rod. Its tail end (5-4), (5-5) is connected with the first connecting seat (5) through a rotary pair, and its head end is divided into a single-hole surface (5-1) and a double-hole surface (5-2), (5-3).

[0047] As shown in Figure 3 b) The second connecting rod (6) is shown as a T-shaped rod. Its tail end (6-4), (6-5) is connected with the second connecting seat (6) through a rotary pair, and its head end is divided into a single-hole surface (6-3) and a double-hole surface (6-1), (6-2).

[0048] As shown in Figure 3 c) The third connecting rod (7) is shown as a T-shaped rod. Its tail end (7-4) is connected with the fourth connecting seat (8) through a rotary pair, and its head end is divided into a single-hole surface (7-1) and a double-hole surface (7-2), (7-3). The seventh connecting rod (11) has the same structure and size as the third connecting rod (7).

[0049] As shown in Figure 3 d) The fourth connecting rod (8) is shown as a T-shaped rod. Its tail end (8-4) is connected with the fifth connecting rod (9) through a rotary pair, and its head end is divided into a single-hole surface (8-3) and a double-hole surface (8-1), (8-2). The sixth connecting rod (10) has the same structure and size as the fourth connecting rod (8).

[0050] As shown in Figure 3 e) The fifth connecting rod (9) is a long straight rod. One end (9-1), (9-2) is connected with the third connecting seat (15) through a rotary pair, and the other end (9-3) is connected with the tail end (8-4) of the fourth connecting rod (8) through a rotary pair. The eighth connecting rod (12) has the same structure and size as the fifth connecting rod (9).

[0051] The first connecting rod (5), the second connecting rod (6), the third connecting rod (7), the fourth connecting rod (8), the fifth connecting rod (9), the sixth connecting rod (10), the seventh connecting rod (11), and the eighth connecting rod (12) should not exceed the diameter of the spherical shell.

[0052] As shown in Figure 4 The first connecting seat (13) is provided with a large hole (13-1) at the top for connecting with each connecting rod through a rotating pair, and is provided with two small holes (13-2) and (13-3) at the bottom for fixedly connecting with each spherical shell. The second connecting seat (14), the third connecting seat (15), the fourth connecting seat (16), the fifth connecting seat (17), and the sixth connecting seat (18) have the same shape as the first connecting seat (13).

[0053] Specific use method:

[0054] A multi-loop spherical robot derived from a Bricard mechanism can complete single-degree-of-freedom driving folding and unfolding deformation, as shown in Figure 5 The two states of the spherical robot are shown. Figure 5 a) is the completely folded state of the spherical robot, in which the four spherical shells of the mechanism are completely folded, and the overall shape is spherical. The driving motor (19) drives the first spherical shell (1), the second spherical shell (2), the third spherical shell (3), and the fourth spherical shell (4) to separate, and after complete unfolding, the four spherical shells are separated from each other, as shown in Figure 5 b).

[0055] A multi-loop spherical robot derived from a Bricard mechanism can complete passive rolling, including rolling straight and rolling steering. As shown in Figure 6 The action of the spherical robot completing one cycle of passive rolling is shown. Figure 6 a) is the completely folded state of the spherical robot, in which the four spherical shells of the mechanism are completely folded, and the overall shape is spherical. The driving motor (19) drives the first spherical shell (1), the second spherical shell (2), the third spherical shell (3), and the fourth spherical shell (4) to separate, and after complete unfolding, the four spherical shells are separated from each other, as shown in Figure 6 b), when the centroid projection position exceeds the support area, and the forward tipping occurs, as shown in Figure 6 c). Figure 6d) is shown, so as to achieve rolling straight by the spherical profile and the dumping kinetic energy. The principle of rolling steering is similar to that of rolling straight. When the spherical robot reaches the steering critical position during the rolling straight, the opening and closing speed of the spherical shell is changed by adjusting the rotating speed of the driving motor (19), and the steering trend is formed by the contact between the spherical shell and the ground during the opening and closing, so as to achieve steering.

[0056] A multi-loop spherical robot derived from the Bricard mechanism can complete peristalsis. As shown in Figure 7 the action of completing a cycle of peristalsis of the spherical robot is shown. Figure 7 a) is the completely folded state of the spherical robot. In this state, the four spherical shells of the mechanism are completely folded, and the overall shape is spherical. The driving motor (19) is forward rotated to drive the first spherical shell (1), the second spherical shell (2) and the third spherical shell (3), the fourth spherical shell (4) to separate, and the third spherical shell (3), the fourth spherical shell (4) is lifted forward, as shown in Figure 7 b) is shown, and then the third spherical shell (3), the fourth spherical shell (4) is tilted forward and contacted with the ground. At this time, the driving motor (19) is reversed, so that the first spherical shell (1), the second spherical shell (2) is folded inward, as shown in Figure 7 c) is shown, so that the whole mechanism peristalsis forward.

[0057] A multi-loop spherical robot derived from the Bricard mechanism can complete spinning. As shown in Figure 8 the action of completing a cycle of spinning of the spherical robot is shown. Figure 8 a) is the completely folded state of the spherical robot. In this state, the four spherical shells of the mechanism are completely folded, and the overall shape is spherical. The driving motor (19) is forward rotated to drive the first spherical shell (1), the second spherical shell (2) and the third spherical shell (3), the fourth spherical shell (4) to separate Figure 7 b), and the driving motor (19) is reversed to close the spherical shell to achieve spinning, as shown in Figure 8 b) - c) is shown.

Claims

1. A multi-loop spherical robot derived from Bricard mechanism, characterized in that: A kind of multi-loop spherical robot based on Bricard mechanism derivation, which is composed of first spherical shell, second spherical shell, third spherical shell, fourth spherical shell, first connecting seat, second connecting seat, third connecting seat, fourth connecting seat, fifth connecting seat, sixth connecting seat, first connecting rod, second connecting rod, third connecting rod, fourth connecting rod, fifth connecting rod, sixth connecting rod, seventh connecting rod, eighth connecting rod, drive motor.

2. The multi-loop spherical robot based on Bricard mechanism derivation according to claim 1, wherein: the single-hole surface at the first end of the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod, the sixth connecting rod and the seventh connecting rod is connected to the double-hole surface at the first end of the first connecting rod through a revolute joint, i.e., the single-hole surface at the first end of the first connecting rod is connected to the double-hole surface at the first end of the second connecting rod through a revolute joint, the single-hole surface at the first end of the second connecting rod is connected to the double-hole surface at the first end of the seventh connecting rod through a revolute joint, the single-hole surface at the first end of the seventh connecting rod is connected to the double-hole surface at the first end of the sixth connecting rod through a revolute joint, the single-hole surface at the first end of the sixth connecting rod is connected to the double-hole surface at the first end of the third connecting rod through a revolute joint, the single-hole surface at the first end of the third connecting rod is connected to the double-hole surface at the first end of the fourth connecting rod through a revolute joint, the single-hole surface at the first end of the fourth connecting rod is connected to the double-hole surface at the first end of the first connecting rod through a revolute joint, forming a Bricard closed-loop structure; the tail end of the first connecting rod is connected to the first connecting seat through a revolute joint, the tail end of the second connecting rod is connected to the second connecting seat through a revolute joint, the tail end of the third connecting rod is connected to the fourth connecting seat through a revolute joint, the tail end of the fourth connecting rod is connected to the fifth connecting rod through a revolute joint, one end of the fifth connecting rod is connected to the third connecting seat through a revolute joint, the tail end of the sixth connecting rod is connected to the sixth connecting seat through a revolute joint, the tail end of the seventh connecting rod is connected to one end of the eighth connecting rod through a revolute joint, and one end of the eighth connecting rod is connected to the fifth connecting seat through a revolute joint; the first spherical shell is fixedly connected to the first connecting seat through a bolt hole, the second spherical shell is fixedly connected to the second connecting seat through a bolt hole, the third spherical shell is fixedly connected to the third connecting seat and the fourth connecting seat through a bolt hole, and the fourth spherical shell is fixedly connected to the fifth connecting seat and the sixth connecting seat through a bolt hole, forming a Bennett loop special-shaped structure; the body of the drive motor is fixedly connected to the first spherical shell through bolt holes on both sides, and the shaft of the drive motor is fixedly connected to the second spherical shell through bolt holes on both sides. The driving motor drives the first spherical shell and the second spherical shell to move through the rotary pair, the first spherical shell drives the fixedly connected first connecting seat to move, and the second spherical shell drives the fixedly connected second connecting seat to move; the first connecting seat drives the first connecting rod to move through the rotary pair, the second connecting seat drives the second connecting rod to move through the rotary pair, the first connecting rod drives the fourth connecting rod to move through the rotary pair, and the second connecting rod drives the seventh connecting rod to move through the rotary pair; the fourth connecting rod drives the third connecting rod and the fifth connecting rod to move through the rotary pair, the seventh connecting rod drives the sixth connecting rod and the eighth connecting rod to move through the rotary pair; the third connecting rod drives the fourth connecting seat to move through the rotary pair, the fifth connecting rod drives the third connecting seat to move through the rotary pair, the sixth connecting rod drives the sixth connecting seat to move through the rotary pair, and the eighth connecting rod drives the fifth connecting seat to move through the rotary pair; the third connecting seat and the fourth connecting seat drive the fixedly connected third spherical shell to move, and the fifth connecting seat and the sixth connecting seat drive the fixedly connected fourth spherical shell to move.

3. The multi-loop spherical robot derived from the Bricard mechanism according to claim 1, wherein: the first spherical shell is in the shape of a quarter of a sphere, has two bolt holes on the surface for fixedly connecting with the first connecting seat, has three through holes for fixedly connecting with the front face of the body of the driving motor, and has four through holes for fixedly connecting with the back face of the body of the driving motor; the second spherical shell is in the shape of a quarter of a sphere, has two bolt holes on the surface for fixedly connecting with the second connecting seat, has five through holes for fixedly connecting with one face of the rotating shaft of the driving motor, and has five through holes for fixedly connecting with the other face of the rotating shaft of the driving motor; the third spherical shell is in the shape of a quarter of a sphere, has two bolt holes on the surface for fixedly connecting with the third connecting seat, and has two bolt holes for fixedly connecting with the fourth connecting seat; the fourth spherical shell is in the shape of a quarter of a sphere, has two bolt holes on the surface for fixedly connecting with the fifth connecting seat, and has two bolt holes for fixedly connecting with the sixth connecting seat; the first connecting rod is in the shape of a T-like shape, has a single-hole face and a double-hole face at the head end, and is connected with the first connecting seat through a rotary pair at the tail end; the second connecting rod is in the shape of a T-like shape, has a single-hole face and a double-hole face at the head end, and is connected with the second connecting seat through a rotary pair at the tail end; the third connecting rod is in the shape of a T-like shape, has a single-hole face and a double-hole face at the head end, and is connected with the fourth connecting seat through a rotary pair at the tail end; the seventh connecting rod has the same structure and size as the third connecting rod; the fourth connecting rod is in the shape of a T-like shape, has a single-hole face and a double-hole face at the head end, and is connected with the fifth connecting rod through a rotary pair at the tail end; the sixth connecting rod has the same structure and size as the fourth connecting rod; the fifth connecting rod is a long straight rod, has one end connected with the third connecting seat through a rotary pair and the other end connected with the tail end of the fourth connecting rod through a rotary pair; and the eighth connecting rod has the same structure and size as the fifth connecting rod. The lengths of the first connecting rod, the second connecting rod, the third connecting rod, the fourth connecting rod, the fifth connecting rod, the sixth connecting rod, the seventh connecting rod and the eighth connecting rod should not exceed the diameter of the spherical shell; The first connecting seat, the second connecting seat, the third connecting seat, the fourth connecting seat, the fifth connecting seat and the sixth connecting seat are all identical in shape, are provided with large through holes at the top for being connected with the connecting rods through rotating pairs, and are provided with two small through holes at the bottom for being fixedly connected with the spherical shells. 4.The multi-loop spherical robot based on Bricard mechanism according to claim 1, characterized in that: The combination of the bar and the spherical shell with special shapes combines the Bricard mechanism and the Bennett mechanism, expands the motion space, and has a larger folding and unfolding step length compared with the single-power steerable spherical robot based on the Bennett mechanism; compared with the three-loop spherical robot based on the Bennett mechanism, the number of driving motors is reduced, the control is simple, the reliability is high, and the mass of the whole machine is also reduced. 5.The multi-loop spherical robot based on Bricard mechanism according to claim 1, characterized in that: The combination of the folding and unfolding characteristics of the spatial over-constrained mechanism and the flexible motion performance of the spherical robot has three motion gaits of passive rolling, peristalsis and self-rotation by changing the folding and unfolding positions and the landing areas, wherein the passive rolling gait can utilize the rolling motion of the spherical shell, has good flexibility, and can realize fast movement on a flat road; the peristalsis gait has better ground stability, and can realize small-step precise linear motion; the self-rotation gait can utilize the rotation motion around the central axis to realize the change of the motion direction angle, and the three motion gaits can be switched according to different working requirements to realize the traversal motion of the working area.

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