A single-actuated steerable spherical robot based on a Bennett mechanism

Abstract

A single power steering spherical robot based on Bennett mechanism, which is a spatial single closed chain mechanism. The single power steering spherical robot based on Bennett mechanism is composed of a first connecting rod (1), a second connecting rod (2), a third connecting rod (3), a fourth connecting rod (4), a first spherical mechanism (9), a second spherical mechanism (8), a third spherical mechanism (5), a fourth spherical mechanism (6) and a driving motor (7). By controlling the forward and reverse rotation of the motor, the robot can realize straight motion and steering motion, and will be well applied in the fields of education, entertainment and military.

Description

TECHNICAL FIELD

[0001] The application relates to a single-power steerable spherical robot based on a Bennett mechanism, in particular to a single-power steerable spherical robot based on a spatial four-bar Bennett mechanism, which drives the robot to move straight and steer by controlling the forward and reverse rotation of a motor and the rotation time. BACKGROUND

[0002] The Bennett mechanism is a single-degree-of-freedom spatial linkage mechanism composed of four rotating pairs and specially arranged, and the mechanism is simple and compact. The spherical body can be divided into four parts and combined with the mechanism by utilizing the characteristics, a new configuration spherical robot is obtained by changing the configuration of the spherical body, and the spherical robot has the abilities of straight movement and steering movement.

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

[0004] The application aims to solve the technical problem that the spherical robot generally has poor motion stability and the single-degree-of-freedom mechanism generally does not have the ability to switch the motion mode.

[0005] A single-power steerable spherical robot based on a Bennett mechanism comprises a first connecting rod, a second connecting rod, a third connecting rod, a fourth connecting rod, a first spherical mechanism, a second spherical mechanism, a third spherical mechanism and a fourth spherical mechanism, and a driving motor.

[0006] The structure of the parts of the mechanism is as follows:

[0007] The first connecting rod is in the shape of an elongated rod, one end of the first connecting rod is connected with the second connecting rod through a rotating pair, and the other end of the first connecting rod is connected with the fourth connecting rod through a rotating pair. Two bolt holes are arranged on the plane of the rotating pair connected with the fourth connecting rod, the bolt holes are countersunk, and the head of the bolt is not higher than the surface of the first connecting rod. The distance between the two holes is the same as the distance between the two holes of the first spherical mechanism. The first connecting rod is fixedly connected with the first spherical mechanism through a bolt; the third connecting rod has the same structure and size as the first connecting rod, and the connection mode of the third connecting rod and the third spherical mechanism is the same as the connection mode of the first connecting rod and the first spherical mechanism.

[0008] The second connecting rod is in the shape of an elongated rod, one end of which is connected to the first connecting rod through a rotating joint, and the other end is connected to the third connecting rod through a rotating joint. The plane where the rotating joint of the third connecting rod is located is provided with two bolt holes, which are countersunk, and the head of the bolt should not be higher than the surface of the second connecting rod. The distance between the two holes is the same as that between the two holes of the second spherical mechanism, and they are fixedly connected through a bolt and the second spherical mechanism; the fourth connecting rod has the same structure and size as the second connecting rod, and the connection mode of the fourth connecting rod and the fourth spherical mechanism is the same as that of the second connecting rod and the second spherical mechanism.

[0009] The first spherical mechanism is in the shape of a quarter sphere. Its surface is provided with two bolt holes for fixed connection with the first connecting rod; the second spherical mechanism is in the shape of a quarter sphere. Its surface is provided with two bolt holes for fixed connection with the second connecting rod; the third spherical mechanism is in the shape of a quarter sphere. Its surface is provided with two bolt holes for fixed connection with the third connecting rod; the fourth spherical mechanism is in the shape of a quarter sphere. Its surface is provided with two bolt holes for fixed connection with the fourth connecting rod.

[0010] The first spherical mechanism, the second spherical mechanism, the third spherical mechanism, and the fourth spherical mechanism are all externally provided with three grooves for reducing the weight of the spherical mechanism, achieving lightweight design, and increasing the friction with the ground.

[0011] The driving motor is installed at the rotating joint where the third connecting rod and the fourth connecting rod are connected. One side of the driving motor is connected to the third connecting rod, and the other side is connected to the fourth connecting rod.

[0012] The connection mode of the parts constituting the mechanism is as follows:

[0013] One end of the first connecting rod is connected to one end of the second connecting rod through a rotating joint, and the other end of the first connecting rod is connected to one end of the fourth connecting rod through a rotating joint. The other end of the second connecting rod is connected to one end of the third connecting rod through a rotating joint. The other end of the third connecting rod is connected to the other end of the fourth connecting rod through a rotating joint.

[0014] The first spherical mechanism is fixedly connected to the first connecting rod through a bolt, the second spherical mechanism is fixedly connected to the second connecting rod through a bolt, the third spherical mechanism is fixedly connected to the third connecting rod through a bolt, and the fourth spherical mechanism is fixedly connected to the fourth connecting rod through a bolt.

[0015] The driving motor is installed at the rotating joint where the third connecting rod and the fourth connecting rod are connected. One side of the driving motor is connected to the third connecting rod, and the other side is connected to the fourth connecting rod.

[0016] The length of the first connecting rod, the second connecting rod, the third connecting rod, and the fourth connecting rod should not exceed the smaller diameter of the spherical mechanism.

[0017] The driving motor drives the connected third connecting rod and fourth connecting rod to move through the rotating pair, the third connecting rod drives the first connecting rod to move through the rotating pair, and the fourth connecting rod drives the second connecting rod to move through the rotating pair, and each connecting rod drives the fixedly connected spherical mechanism to move.

[0018] The single-power steerable spherical robot based on the Bennett mechanism has the advantages that the single-power steerable spherical robot based on the Bennett mechanism is a single-degree-of-freedom mechanism, the movement can be controlled through a single driving motor, the spherical mechanism and the single-closed-chain mechanism are combined, the structure is simple, the driving motor is reversed and the rotation time is utilized to drive the mechanism to move straight and steer, and the single-power steerable spherical robot based on the Bennett mechanism is easy to manufacture and process. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A single-power steerable spherical robot based on a Bennett mechanism

[0020] Figure 2 Structure diagram of the first connecting rod and the third connecting rod

[0021] Figure 3 Structure diagram of the second connecting rod and the fourth connecting rod

[0022] Figure 4 Structure diagram of the first spherical mechanism, the second spherical mechanism, the third spherical mechanism and the fourth spherical mechanism

[0023] Figure 5 Rolling straight gait schematic diagram of the mechanism

[0024] Figure 6 Creeping straight gait schematic diagram of the mechanism

[0025] Figure 7 Steering gait schematic diagram of the mechanism DETAILED DESCRIPTION

[0026] The application will be further described in detail below with reference to the drawings.

[0027] As shown in Figure 1 a single-power steerable spherical robot based on a Bennett mechanism comprises a first connecting rod (1), a second connecting rod (2), a third connecting rod (3), a fourth connecting rod (4), a first spherical mechanism (9), a second spherical mechanism (8), a third spherical mechanism (5), a fourth spherical mechanism (6), and a driving motor (7).

[0028] As shown in Figure 2As shown, the first connecting rod (1) is an elongated rod, one end (1-3) is connected with the second connecting rod (2) through a rotating pair, the other end (1-4) is connected with the fourth connecting rod (4) through a rotating pair. The plane where the rotating pair is connected with the fourth connecting rod is provided with bolt holes (1-1) and (1-2), which are countersunk structures, and the head of the bolt should not be higher than the surface of the first connecting rod (1). The distance between the two holes is the same as that of the first spherical mechanism (9). It is fixedly connected through a bolt and the first spherical mechanism (9); the structure and size of the third connecting rod (3) are the same as those of the first connecting rod (1), and the connection mode of the third spherical mechanism (5) is the same as that of the first connecting rod (1) and the first spherical mechanism (9).

[0029] As shown in Figure 3 , the second connecting rod (2) is an elongated rod, one end (2-3) is connected with the first connecting rod (1) through a rotating pair, the other end (2-4) is connected with the third connecting rod (3) through a rotating pair. The plane where the rotating pair is connected with the third connecting rod is provided with bolt holes (2-1) and (2-2), which are countersunk structures, and the head of the bolt should not be higher than the surface of the second connecting rod (2). The distance between the two holes is the same as that of the second spherical mechanism (8). It is fixedly connected through a bolt and the second spherical mechanism (8); the structure and size of the fourth connecting rod (4) are the same as those of the second connecting rod (2), and the connection mode of the fourth spherical mechanism (6) is the same as that of the second connecting rod (2) and the second spherical mechanism (8).

[0030] As shown in Figure 4 a, the first spherical mechanism (9) is a quarter of a sphere. Its surface is provided with bolt holes (9-1) and (9-2) for connecting with the first connecting rod (1). The second spherical mechanism (8) has the same structure and size as the first spherical mechanism (9). Its surface is provided with two bolt holes for fixedly connecting with the second connecting rod (2); the third spherical mechanism (5) has the same structure and size as the first spherical mechanism (9). Its surface is provided with two bolt holes for fixedly connecting with the third connecting rod (3); the fourth spherical mechanism (6) has the same structure and size as the first spherical mechanism (9). Its surface is provided with two bolt holes for fixedly connecting with the fourth connecting rod (4).

[0031] As shown in Figure 4 b, the first spherical mechanism (9) is provided with three grooves (9-1), (9-2) and (9-3) outside, which are used to reduce the weight of the spherical mechanism and realize lightweight design, and can also increase the friction force with the ground; the second spherical mechanism (8), the third spherical mechanism (5) and the fourth spherical mechanism (6) have the same structure and size as the first spherical mechanism (9).

[0032] The driving motor (7) is installed at the rotary pair connected by the third connecting rod (3) and the fourth connecting rod (4). One side of the driving motor (7) is connected with the third connecting rod (3), and the other side is connected with the fourth connecting rod (4).

[0033] The connecting mode of the parts constituting the mechanism is as follows:

[0034] The first connecting rod one end (1-3) is rotatably connected with the second connecting rod one end (2-3) through a rotary pair, and the first connecting rod other end (1-4) is rotatably connected with the fourth connecting rod one end through a rotary pair. The second connecting rod other end (2-4) is rotatably connected with the third connecting rod one end through a rotary pair. The third connecting rod other end is rotatably connected with the fourth connecting rod other end through a rotary pair.

[0035] The first spherical mechanism (9) is fixedly connected with the first connecting rod (1) through bolt holes (9-1) and (9-2), the second spherical mechanism (8) is fixedly connected with the second connecting rod (2) through a bolt, the third spherical mechanism (5) is fixedly connected with the third connecting rod (3) through a bolt, and the fourth spherical mechanism (6) is fixedly connected with the fourth connecting rod (4) through a bolt.

[0036] The driving motor (7) is installed at the rotary pair connected by the third connecting rod (3) and the fourth connecting rod (4). One side of the driving motor (7) is connected with the third connecting rod (3), and the other side is connected with the fourth connecting rod (4).

[0037] The lengths of the first connecting rod (1), the second connecting rod (2), the third connecting rod (3), and the fourth connecting rod (4) should not exceed the smaller diameter of the spherical mechanism.

[0038] The driving motor drives the third connecting rod (3) and the fourth connecting rod (4) to move through a rotary pair, the third connecting rod (3) drives the first connecting rod (1) to move through a rotary pair, and the fourth connecting rod (4) drives the second connecting rod (2) to move through a rotary pair. Each connecting rod drives the fixedly connected spherical mechanism to move.

[0039] Specific use method:

[0040] The single-power steerable spherical robot based on the Bennett mechanism can realize two kinds of straight walking gaits, one of which is a rolling straight walking gait, and the other of which is a peristaltic straight walking gait.

[0041] In the rolling straight walking gait, first, the single-power steerable spherical robot based on the Bennett mechanism is located at the starting pose of the rolling straight walking gait shown in a, and the mechanism is completely retracted, and the shape is spherical. Figure 5 When straight walking is required, the driving motor (7) is forward rotated to drive the third connecting rod (3) and the fourth connecting rod (4) to move through a rotary pair, so as to drive the entire spherical mechanism to move, thereby realizing the action of the gravity center offset of the whole mechanism, that is, as shown in b. Figure 5b, when the projection of the center of the mechanism on the ground exceeds the support area due to inertia, i.e. the roll is achieved, as shown in Figure 5 c. At this time the drive motor (7) is reversed, bringing the third link (3) and the fourth link (4) to rotate, thus bringing the entire mechanism to fold, as shown in Figure 5 d. At this time the center of the mechanism on the ground exceeds the support area due to inertia due to the shift of the center of gravity of the mechanism, thus bringing the entire mechanism to roll forward, as shown in Figure 5 e. After rolling 3 / 4 of a turn, it can return to the initial pose, i.e. the end of the rolling straight walking gait, as shown in Figure 5 f. Thus a complete rolling straight walking gait of the robot is achieved, Figure 5 a, Figure 5 b, Figure 5 c, Figure 5 d, Figure 5 e, Figure 6 f is a schematic diagram of the rolling straight walking gait of the mechanism.

[0042] In the peristaltic straight walking gait, first the single-actuated steerable spherical robot based on the Bennett mechanism is in the initial pose of the peristaltic straight walking gait, as shown in Figure 6 a. The mechanism is completely folded, with a spherical shape. When it is time to walk straight, the drive motor (7) is turned on to bring the third link (3) and the fourth link (4) to move, thus bringing the entire spherical mechanism to move, through the unfolding of the spherical mechanism, the center of the mechanism on the ground exceeds the support area due to inertia, to achieve the shift of the center of gravity of the mechanism, i.e. the pose shown in Figure 6 b. Then the drive motor (7) is reversed to make the spherical mechanism fold, i.e. the pose shown in Figure 6 c. At this time the center of gravity of the mechanism shifts, due to the effect of inertia and at the same time the drive motor (7) is reversed to make the mechanism roll and at the same time constantly fold, i.e. the pose shown in Figure 6 d. Then the drive motor (7) is turned on to control the angle of opening of the spherical mechanism by controlling the rotation time of the motor, i.e. to start the peristaltic straight walking gait, as shown in Figure 6 e-f. Then the drive motor (7) is reversed to make the entire mechanism fold, as shown in g. At this time the drive motor (7) is turned on, due to the change in the position of the center of the mechanism, the mechanism rolls slightly, and after the mechanism unfolds it returns to the initial pose of the peristaltic forward walking gait, as shown in f. Thus a complete peristaltic forward walking gait of the robot is achieved, Figure 6 a, Figure 6 b, Figure 6 c, Figure 6 d, Figure 6 e, Figure 6 f, Figure 7 g, Figure 7 h is a schematic diagram of the peristaltic straight walking gait of the mechanism.

[0043] Single-actuated steering spherical robot based on Bennett mechanism can realize steering gait. First, the mechanism is in the initial pose of steering gait as shown in Figure 7 a, the mechanism is fully retracted, the shape of the mechanism is spherical, when steering, the driving motor (7) is forward rotated to make the mechanism expand, by controlling the rotation time of the motor, the angle of the mechanism opening is controlled, thus steering is realized, due to the shift of the overall center of gravity of the mechanism, the mechanism is in the pose as shown in Figure 7 b. Then the driving motor (7) is reversed to make the spherical mechanism retract, as shown in Figure 7 c. The fully retracted state of the robot is shown in Figure 7 d. Due to the effect of inertia, the center of gravity of the mechanism changes, the mechanism realizes rolling motion for one cycle, as shown in Figure 7 e. The end action pose of the mechanism steering gait is shown in Figure 7 f. Thus a complete steering gait of the robot is realized, Figure 7 a, Figure 7 b, Figure 7 c, Figure 7 d, ​ e, ​ f is the schematic diagram of the mechanism steering gait.

Claims

1. A single-actuated steerable spherical robot based on Bennett mechanism, characterized by: A single-actuated steering spherical robot based on Bennett mechanism is a single closed chain structure, comprising a first connecting rod (1), a second connecting rod (2), a third connecting rod (3), a fourth connecting rod (4), a first spherical mechanism (9), a second spherical mechanism (8), a third spherical mechanism (5), and a fourth spherical mechanism (6); and a driving motor (7); The first connecting rod (1) is in the shape of an elongated rod, one end (1-3) of which is connected to the second connecting rod (2) through a rotating joint, and the other end is connected to the fourth connecting rod (4) through a rotating joint; the first connecting rod (1) is provided with bolt holes 1-1 and 1-2 on the plane where the rotating joint with the fourth connecting rod is located, the bolt holes 1-1 and 1-2 are countersunk structures, the head of the bolt is not higher than the surface of the first connecting rod (1), the distance between the two holes is the same as that between the two holes of the first spherical mechanism (9), and the first connecting rod (1) is fixedly connected to the first spherical mechanism (9) through a bolt; the third connecting rod (3) has the same structure and size as the first connecting rod (1), and is connected to the third spherical mechanism (5) in the same way as the first connecting rod (1) is connected to the first spherical mechanism (9); The second connecting rod (2) is in the shape of an elongated rod, one end (2-3) of which is connected to the first connecting rod (1) through a rotating joint, and the other end (2-4) is connected to the third connecting rod (3) through a rotating joint; the second connecting rod (2) is provided with bolt holes 2-1 and 2-2 on the plane where the rotating joint with the third connecting rod is located, the bolt holes 2-1 and 2-2 are countersunk structures, the head of the bolt is not higher than the surface of the second connecting rod (2), the distance between the two holes is the same as that between the two holes of the second spherical mechanism (8), and the second connecting rod (2) is fixedly connected to the second spherical mechanism (8) through a bolt; the fourth connecting rod (4) has the same structure and size as the second connecting rod (2), and is connected to the fourth spherical mechanism (6) in the same way as the second connecting rod (2) is connected to the second spherical mechanism (8); The first spherical mechanism (9) is in the shape of a quarter sphere, and is provided with bolt holes 9-1 and 9-2 on the surface thereof for connection with the first connecting rod (1); the second spherical mechanism (8) has the same structure and size as the first spherical mechanism (9), and is provided with two bolt holes on the surface thereof for fixed connection with the second connecting rod (2); the third spherical mechanism (5) has the same structure and size as the first spherical mechanism (9), and is provided with two bolt holes on the surface thereof for fixed connection with the third connecting rod (3); and the fourth spherical mechanism (6) has the same structure and size as the first spherical mechanism (9), and is provided with two bolt holes on the surface thereof for fixed connection with the fourth connecting rod (4); The first spherical mechanism (9) is externally provided with three grooves for reducing the weight of the spherical mechanism; the second spherical mechanism (8), the third spherical mechanism (5), and the fourth spherical mechanism (6) have the same structure and size as the first spherical mechanism; The driving motor (7) is installed at the rotating joint where the third connecting rod (3) and the fourth connecting rod (4) are connected, one side of the driving motor (7) is the third connecting rod (3), and the other side is the fourth connecting rod (4). The first spherical mechanism (9) is fixedly connected with the first connecting rod (1) through bolt holes 9-1 and 9-2, the second spherical mechanism (8) is fixedly connected with the second connecting rod (2) through a bolt, the third spherical mechanism (5) is fixedly connected with the third connecting rod (3) through a bolt, and the fourth spherical mechanism (6) is fixedly connected with the fourth connecting rod (4) through a bolt.

2. A single-actuated steerable spherical robot based on Bennett mechanism as claimed in claim 1 characterized in that: The Bennett mechanism, i.e., the first connecting rod (1), the second connecting rod (2), the third connecting rod (3), and the fourth connecting rod (4), has a length not more than the diameter of the spherical mechanism.

3. A single-actuated steerable spherical robot based on Bennett mechanism as claimed in claim 1, wherein: The driving motor drives the third connecting rod (3) to move through the rotary pair connected with the fourth connecting rod (4), the third connecting rod (3) drives the first connecting rod (1) to move through the rotary pair connected therewith, and the fourth connecting rod (4) drives the second connecting rod (2) to move through the rotary pair connected therewith, while the rotary pairs of the first connecting rod (1) and the second connecting rod (2) can also move, each connecting rod drives the fixedly connected spherical mechanism to move, the pose is transformed, the center of gravity is constantly changed, and the robot moves, the forward and reverse rotation of the motor and the rotation time are controlled to realize the straight movement and steering movement of the robot.

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