Parallel type three-finger paw driven by moving pair

Abstract

The invention relates to an automatic manipulator, in particular to a parallel type three-finger gripper driven by a sliding pair. The parallel type three-finger paw driven by the moving pair has the function of flexibly grabbing large objects and has the advantages of being high in stability and wide in application range. According to the technical scheme, the parallel type three-finger gripper driven by the sliding pair is characterized in that each finger comprises a palm fixing platform and three finger branches arranged on the palm fixing platform; each finger branch comprises a first joint, a second joint and a third joint which are sequentially connected from bottom to top from the palm fixed platform.

Description

Technical Field

[0001] The invention relates to an automated manipulator, in particular to a parallel three-finger gripper driven by a mobile pair. Background Art

[0002] As a key component of the robot's end effector, the robot gripper is designed for grabbing target workpieces and is widely used in automated production, material handling, logistics warehousing and other fields. Existing robot grippers generally use a serial structure design in pursuit of cost-effectiveness and control convenience. However, serial robot grippers have problems such as limited accuracy, limited load-bearing capacity, high maintenance costs and limited movement speed in actual applications.

[0003] Compared with the traditional serial mechanism design, the parallel mechanism is composed of a fixed platform, a moving platform and several motion branches in parallel. It has the advantages of compact structure, high precision and good rigidity, and has been widely used in complex application scenarios such as heavy-load environment and high-speed motion. However, the current parallel robot gripper still has problems such as small working space and poor flexibility, and has certain limitations in application.

[0004] CN113858238A discloses a robot bionic hand and its grasping method and system, but the bionic hand has insufficient workpiece clamping stability and its claws are easily damaged when facing heavy workpieces or high-speed working environments. CN218911553U discloses a hydraulic two-claw manipulator for collecting large-size gravel, but its design is targeted at specific working environments, has a narrow scope of application, and lacks flexibility. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the above-mentioned background technology and to provide a parallel three-finger gripper driven by a mobile sub-drive, which should have the function of flexibly grasping larger objects and have the advantages of strong stability and a wide range of applications.

[0006] The technical solution of the present invention is:

[0007] A parallel three-finger gripper driven by a mobile pair, characterized in that: the finger comprises a palm fixing platform and three finger branches arranged on the palm fixing platform;

[0008] The finger branch includes a first joint, a second joint and a third joint which are sequentially connected from bottom to top from a palm fixed platform.

[0009] The first joint includes a fixed platform mounted on the palm fixed platform and two first branches and a second branch at the bottom end respectively connected to three vertex positions on the fixed platform;

[0010] The second joint comprises a first movable platform whose three vertices at the bottom are respectively connected to the top of the first branch and the top of the second branch, and three third branches whose bottoms are respectively connected to the three vertices of the first movable platform;

[0011] The third joint comprises three top corners at the bottom end respectively connected to the second moving platform at the top of the three third branches and a seventh connecting rod installed at the center of the upper surface of the second moving platform;

[0012] The first branch includes a first Hooke's joint, a first translation pair and a first rotation pair connected in sequence from the fixed platform;

[0013] The second branch includes a first ball joint, a second translation pair, and a second rotation pair connected in sequence from the fixed platform;

[0014] The third branch includes a third rotation pair, a third translation pair and a fourth rotation pair sequentially connected from the first moving platform;

[0015] The palm fixed platform, the fixed platform, the first movable platform and the second movable platform are all regular triangle flat plates.

[0016] The rotation axis of the first rotation pair is perpendicular to one side of the equilateral triangle and perpendicular to the rotation axis of the second rotation pair.

[0017] The rotation axes of the third rotation pair and the fourth rotation pair are both parallel to the rotation axis of the second rotation pair.

[0018] The first moving pair, the second moving pair and the third moving pair are all driving pairs equipped with cylinders.

[0019] The axis of the seventh connecting rod maintains an inclined angle with the plane of the second moving platform.

[0020] The projection of the seventh connecting rod axis on the second moving platform is perpendicular to the rotation axis of the fourth rotating pair and an edge of the second moving platform.

[0021] The first moving pair includes a first connecting rod and a second connecting rod slidingly matched with the first connecting rod;

[0022] The second moving pair includes a third connecting rod and a fourth connecting rod slidably matched with the third connecting rod;

[0023] The third moving pair includes a fifth connecting rod and a sixth connecting rod slidingly matched with the fifth connecting rod.

[0024] The upper end of the seventh connecting rod is provided with a rubber protective sleeve.

[0025] The fixing platforms of the three finger branches connected to the palm fixing platform are arranged symmetrically to the center of the palm fixing platform.

[0026] In the three finger branches connected to the palm fixed platform; in the first finger branch, the vertex angle of the first ball joint is installed on the fixed platform, which coincides with a vertex angle of the palm fixed platform; the vertex angles of the first ball joint are installed on the fixed platforms in the other two finger branches, and are set back to the grasping target.

[0027] The beneficial effects of the present invention are:

[0028] 1. The present invention adopts a parallel connection method, and the external load on the moving platform is jointly borne by multiple independent kinematic chains, so its overall structural rigidity is greater, the structure is more stable, and the bearing capacity is stronger;

[0029] 2. The moving pair in the present invention is a driving pair, which is driven by a cylinder, and the cylinder has the advantages of fast response speed, high production efficiency, strong adaptability to the working environment, etc.;

[0030] 3. The present invention simulates human hands grasping objects, and each finger branch can be independently controlled, which has the advantages of high accuracy, high stability, and good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is one of the three-dimensional structural schematic diagrams of an embodiment of the present invention (first use state).

[0032] Figure 2 It is a schematic diagram of the three-dimensional structure of the finger branch of the present invention.

[0033] Figure 3 It is a schematic diagram of the three-dimensional structure of the first joint of the present invention.

[0034] Figure 4 It is a schematic diagram of the three-dimensional structure of the second joint of the present invention.

[0035] Figure 5 It is a schematic diagram of the three-dimensional structure of the third joint of the present invention.

[0036] Figure 6 This is the second schematic diagram of the three-dimensional structure of the embodiment of the present invention (the second use state).

[0037] Reference numerals:

[0038] Palm fixed platform 1, finger branch 11, first joint 2, fixed platform 21, first branch 22, first Hooke's joint 23, first connecting rod 24, first moving pair 25, second connecting rod 26, first rotating pair 27, second branch 28, first ball joint 29, third connecting rod 210, second moving pair 211, fourth connecting rod 212, second rotating pair 213, first Hooke's joint base 214, cross coupling 215, first rotating pair base 216, second rotating pair base 217, second joint 3, first moving platform 31, third branch 32, third rotating pair 33, fifth connecting rod 34, third moving pair 35, sixth connecting rod 36, fourth rotating pair 37, third rotating pair base 38, fourth rotating pair base 39, third joint 4, second moving platform 41, seventh connecting rod 42. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] Example:

[0041] like Figure 1 As shown, a parallel three-finger gripper driven by a mobile pair includes a palm fixing platform 1 and three finger branches 11 connected to the palm fixing platform in parallel at the bottom. The palm fixing platform is an equilateral triangular plate; the three finger branches connected to the palm fixing platform are installed at the three top corners of the palm fixing platform, and can cooperate to complete the action of retracting and releasing objects. Each finger branch can be independently controlled to simulate human hands grasping objects, which improves the accuracy, stability and flexibility of the gripper when working.

[0042] like Figure 2 As shown, the finger branch includes a first joint 2, a second joint 3, and a third joint 4 connected in sequence from bottom to top. The bottom end of the first joint can be positioned on the palm fixed platform with multiple degrees of freedom, the bottom end of the second joint can be positioned at the top of the first joint with multiple degrees of freedom, and the bottom end of the third joint is positioned at the top of the second joint. Each joint on the finger branch adopts a parallel connection method, and the external load of each moving platform is shared by multiple independent motion chains. Therefore, the overall structural rigidity of the device is greater, the structure is more stable, and the load-bearing capacity is stronger.

[0043] like Figure 3As shown, the first joint includes a fixed platform 21 mounted on the palm fixed platform and two first branches 22 and a second branch 28 connected in parallel to the fixed platform at one end. The fixed platform is an equilateral triangular plate, the bottom ends of the two first branches and one second branch are respectively mounted on the three vertex positions on the upper surface of the fixed platform, and the top ends are connected in parallel to the lower surface of the first movable platform 31 of the second joint; the three branches are arranged symmetrically about the central axis of the fixed platform.

[0044] The first branch includes a first Hooke's joint 23, a first moving pair 25, and a first rotating pair 27 which are connected in sequence starting from the fixed platform. The first Hooke's joint is installed on the upper surface of the fixed platform; the first Hooke's joint includes a first Hooke's joint base 214 installed on the fixed platform and the first moving pair, and a cross coupling 215 installed on the first Hooke's joint base. The first moving pair includes a first connecting rod 24 with a slide groove at one end (the slide groove is coaxially arranged on the first connecting rod) and the other end connected to the first Hooke's joint, and a second connecting rod 26 with one end movably positioned in the slide groove of the first connecting rod. The two ends of the first rotating pair are respectively connected to the other end of the second connecting rod and the lower surface of the first moving platform of the second joint, and the first rotating pair base 216 of the first rotating pair is installed on the lower surface of the second joint.

[0045] The second branch includes a first ball joint 29, a second movable pair 211, and a second rotation pair 213 which are connected in sequence starting from the fixed platform, and the first ball joint is installed on the upper surface of the fixed platform. The second movable pair includes a third connecting rod 210 with a slide groove at one end (the slide groove is coaxially arranged on the third connecting rod) and the other end connected to the first ball joint, and a fourth connecting rod 212 with one end movably positioned in the slide groove of the third connecting rod. The two ends of the second rotation pair are respectively connected to the other end of the fourth connecting rod and the lower surface of the first movable platform of the second joint, and the second rotation pair base 217 of the second rotation pair is installed on the lower surface of the second joint. The rotation axes of the two first rotation pairs are parallel to each other and perpendicular to the rotation axis of the second rotation pair.

[0046] It can be seen from the figure that in the first joint, the rotation axes of the two first rotation pairs are perpendicular to one side of the fixed platform (one side of the equilateral triangle), and at the same time perpendicular to one side of the first movable platform of the second joint (one side of the equilateral triangle).

[0047] And: when the two first branches and one second branch are of equal length and the top end is connected in parallel to the first moving platform of the second branch, the three branches are parallel to each other, and the fixed platform of the first joint is parallel to the first moving platform of the second joint.

[0048] like Figure 4As shown, the second joint includes a first moving platform and three third branches 32 connected in parallel to the first moving platform at one end; the first moving platform is an equilateral triangular plate, the bottom ends of the three third branches are respectively installed at the three vertex positions on the upper surface of the first moving platform, and the top ends are connected in parallel to the second moving platform of the third joint. The three third branches are arranged with the central axis of the first moving platform as the symmetrical center. The three vertex positions on the lower surface of the first moving platform are respectively connected to the first branch and the second branch.

[0049] The third branch includes a third rotation pair 33, a third moving pair 35, and a fourth rotation pair 37 connected in sequence starting from the second moving platform. The third moving pair includes a fifth connecting rod 34 with a slide groove at one end (the slide groove is coaxially arranged on the fifth connecting rod) and the other end connected to the third rotation pair, and a sixth connecting rod 36 with one end movably positioned in the slide groove of the fifth connecting rod and the other end connected to the fourth rotation pair 37; the third rotation pair connects the upper surface of the first moving platform and the other end of the fifth connecting rod, and the third rotation pair base 38 of the third rotation pair is installed on the upper surface of the first moving platform; the fourth rotation pair connects the other end of the sixth connecting rod and the second moving platform of the third joint, and the fourth rotation pair base 39 of the fourth rotation pair is installed on the lower surface of the second moving platform of the third joint. The rotation axes of the third rotation pair and the fourth rotation pair are parallel to each other. The rotation axis of the third rotation pair is parallel to the rotation axis of the second rotation pair and perpendicular to the rotation axis of the first rotation pair.

[0050] It can be seen from the figure that: in the second joint, the rotation axes of the three fourth rotation pairs are parallel to each other and perpendicular to one side of the second moving platform (one side of the equilateral triangle), and the rotation axes of the three third rotation pairs are parallel to each other and perpendicular to the rotation axes of the two first rotation pairs of the first joint.

[0051] In this way, when the three branches of the first joint are of equal length and the three branches of the second joint are of equal length, the fixed platform, the first movable platform, and the second movable platform can correspond to each other up and down.

[0052] And: when the three third branches are of equal length and are connected in parallel to the second moving platforms of the third branches, the three branches are parallel to each other, and the first moving platform of the second joint and the second moving platform of the third joint are parallel to each other.

[0053] like Figure 5 As shown, the third joint includes a second moving platform 41 and a seventh connecting rod 42 whose bottom end is connected to the upper surface of the second moving platform. The second moving platform is an equilateral triangular plate. The seventh connecting rod is installed at the center of the second moving platform, and an inclination angle (preferably 45 degrees) is maintained between the axis of the seventh connecting rod and the upper surface of the second moving platform. In addition, the projection of the axis of the seventh connecting rod on the second moving platform is perpendicular to the axis of rotation of the fourth rotating pair, that is, perpendicular to an edge of the second moving platform (one side of the equilateral triangle).

[0054] like Figure 1 As shown, the three seventh connecting rods are facing the grasped object together, which is convenient for grasping the object; the upper end of the seventh connecting rod is set as a sphere and is installed with a rubber sleeve protective cover to increase the friction during grasping.

[0055] The first moving pair, the second moving pair and the third moving pair are all equipped with cylinders (cylinders are omitted in the figure) as driving pairs, and the purpose of flexibly grasping objects is achieved through the coordinated movement of the first moving pair, the second moving pair and the third moving pair.

[0056] When the present invention is used, it can be divided into the following two types according to different working objectives:

[0057] 1. The target to be grabbed is a block or a sphere (see Figure 1 )

[0058] At this time, the fixing platforms of the three finger branches connected to the palm fixing platform are arranged symmetrically with the center of the palm fixing platform, that is, the top angle of the first ball joint 29 installed on the fixing platform of each finger branch coincides with a top angle of the palm fixing platform; at this time, the seventh connecting rod is tilted toward the grasped target, and the three finger branches can cooperate to complete the operation of retracting and releasing block or spherical objects.

[0059] 2. The grasping target is long or cylindrical (see Figure 6 )

[0060] At this time, the fixing platforms of the three finger branches connected to the palm fixing platform are set at different positions on the palm fixing platform; in the first finger branch, the top angle of the first ball joint 29 installed on the fixing platform coincides with a top angle of the palm fixing platform, so that the seventh connecting rod is tilted toward the center of the palm fixing platform; in the other two finger branches, after the fixing platform is installed on the palm fixing platform, the top angle of the first ball joint 29 is installed on the fixing platform, which is set back to the grasping target (that is, the top angles of the first ball joints are respectively installed on the two fixing platforms, both facing back to the fixed platform in the first finger branch); the three finger branches can cooperate to complete the operation of retracting and releasing long or cylindrical objects.

[0061] The parallel three-finger gripper driven by the mobile sub-drive can achieve the goal of grasping objects more flexibly and accurately. The three independent finger branches are driven by the cylinder to simulate the action of human hands grasping objects. When starting to grasp an object, the parallel three-finger gripper driven by the mobile sub-drive can not only ensure the accuracy of the movement, but also can closely fit the surface of the object through the independent finger branches to ensure the stability of the movement, so as to meet the requirements of industrial production applications.

Claims

1. A parallel three-finger gripper driven by a mobile pair, characterized in that: The finger comprises a palm fixing platform (1) and three finger branches (11) arranged on the palm fixing platform; The finger branch (11) comprises a first joint (2), a second joint (3) and a third joint (4) which are sequentially connected from bottom to top to the palm fixed platform (1); The first joint (2) comprises a fixed platform (21) mounted on the palm fixed platform (1), and two first branches (22) and a second branch (28) whose bottom ends are respectively connected to three top corners of the fixed platform (21); The second joint (3) comprises a first movable platform (31) whose three top corners at the bottom are respectively connected to the top of the first branch (22) and the top of the second branch (28), and three third branches (32) whose bottoms are respectively connected to the three top corners of the first movable platform (31); The third joint (4) comprises a second movable platform (41) whose three top corners at the bottom are respectively connected to the tops of the three third branches (32) and a seventh connecting rod (42) installed at the center of the upper surface of the second movable platform (41); The first branch (22) comprises a first Hooke's joint (23), a first moving pair (25) and a first rotating pair (27) which are sequentially connected starting from the fixed platform (21); The second branch (28) comprises a first ball joint (29), a second moving pair (211) and a second rotating pair (213) which are sequentially connected starting from the fixed platform (21); The third branch (32) comprises a third rotation pair (33), a third movement pair (35) and a fourth rotation pair (37) which are sequentially connected from the first moving platform (31); The palm fixed platform, the fixed platform, the first movable platform and the second movable platform are all regular triangle flat plates.

2. The parallel three-finger gripper driven by a movable pair according to claim 1, characterized in that: The rotation axis of the first rotation pair (27) is perpendicular to one side of the equilateral triangle and perpendicular to the rotation axis of the second rotation pair (213).

3. The parallel three-finger gripper driven by a movable pair according to claim 2 is characterized in that: The rotation axes of the third rotation pair (33) and the fourth rotation pair (37) are both parallel to the rotation axis of the second rotation pair (213).

4. The parallel three-finger gripper driven by a movable pair according to claim 3 is characterized in that: The first moving pair (25), the second moving pair (211) and the third moving pair (35) are all drive pairs equipped with cylinders.

5. The parallel three-finger gripper driven by a movable pair according to claim 4 is characterized in that: The axis of the seventh connecting rod (42) maintains an inclined angle with the plane of the second moving platform (41).

6. The parallel three-finger gripper driven by a movable pair according to claim 5, characterized in that: The projection of the axis of the seventh connecting rod (42) on the second movable platform (41) is perpendicular to the rotation axis of the fourth rotating pair (37) and an edge of the second movable platform (41).

7. The parallel three-finger gripper driven by a movable pair according to claim 6, characterized in that: The first movable pair (25) comprises a first connecting rod (24) and a second connecting rod (26) slidably matched with the first connecting rod (24); The second movable pair (211) comprises a third connecting rod (210) and a fourth connecting rod (212) slidably matched with the third connecting rod (210); The third movable pair (35) comprises a fifth connecting rod (34) and a sixth connecting rod (36) slidably matched with the fifth connecting rod (34).

8. The parallel three-finger gripper driven by a moving pair according to claim 7, characterized in that: The upper end of the seventh connecting rod (42) is provided with a rubber protective sleeve.

9. The parallel three-finger gripper driven by a movable pair according to claim 8, characterized in that: The fixing platform (21) connecting the three finger branches (11) of the palm fixing platform (1) is arranged symmetrically to the center of the palm fixing platform (1).

10. The parallel three-finger gripper driven by a movable pair according to claim 9, characterized in that: In the three finger branches (11) connected to the palm fixed platform (1), in the first finger branch (11), the top angle of the first ball joint (29) installed on the fixed platform (21) coincides with a top angle of the palm fixed platform (1); the top angles of the first ball joint (29) installed on the fixed platforms (21) in the other two finger branches (11) are arranged to face away from the grasping target; The first movable pair (25) comprises a first connecting rod (24) with a slide groove at one end and a second connecting rod (26) with one end movably positioned in the slide groove and the other end connected to the first rotating pair (27); The second movable pair (211) comprises a third connecting rod (210) with a slide groove at one end and a fourth connecting rod (212) with one end movably positioned in the slide groove and the other end connected to the second rotating pair (213); The third movable pair (35) comprises a fifth connecting rod (34) with a sliding groove at one end and a sixth connecting rod (36) with one end movably positioned in the sliding groove and the other end connected to the fourth rotating pair (37).

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