Parallel robots

Abstract

The present invention provides a new type of parallel robot, including two bases, two branch chains and a moving platform, each branch chain includes a lead screw, a spline shaft, a moving seat, a joint and a connecting rod mechanism, the spline shaft and the lead screw in the lead screw are rotatably supported between the two bases, the joint keyway is fitted on the spline shaft, the moving seat is fitted on the spline shaft and is fixedly connected to the nut in the lead screw, the connecting rod mechanism is hinged on the moving seat and connected to the joint, the end of the connecting rod mechanism is hinged with a horizontally arranged connecting seat, a rotating shaft is vertically arranged on the connecting seat, and the moving platform is hinged on the rotating shaft on the connecting seat of the two branch chains. This parallel robot has a four-degree-of-freedom motion capability of three-dimensional translation and one-dimensional rotation through two branch chains, its structure is simple and low-cost, does not contain a complex transmission device, the moving parts are light in weight, the inertia of the movement is small, it is easy to achieve high-speed and high-acceleration dynamic performance, and the movement accuracy and stability are high.

Description

Technical Field

[0001] The invention belongs to the field of robots, and in particular relates to a parallel robot. Background Art

[0002] High-speed parallel robots have been successfully applied to automated production lines in light industry, medicine, food, logistics, electronics and other industries, and are used for high-speed handling, packaging, sorting, etc. of various light, small and scattered materials. Compared with traditional serial robots, high-speed parallel robots can achieve high-speed and high-acceleration motion that serial robots cannot match because the drive device can be arranged on the frame and the master and slave arms can be made of light rods made of carbon fiber, making them the preferred equipment for automated production lines in the above industries. At present, the most widely used robot is the Delta robot that can achieve three degrees of freedom. The traditional Delta robot contains three identical R-(SS)2 branches, which can only achieve three-dimensional translation in space. If the end effector is to rotate around the normal of the moving platform, it is necessary to add a UPU branch between the moving and static platforms of the robot. However, since the UPU branch is severely worn when working at the edge of the workspace for a long time, it is bound to affect the life of the above-mentioned manipulator.

[0003] In addition to the above-mentioned Delta robot, existing four-DOF high-speed parallel robots also contain four branches, and most of them require the relative movement between the dual-motion platforms to realize the rotation of the end effector around the normal direction of the moving platform. However, the limitations of the above-mentioned mechanism are: the four branches are complex in structure and costly, and the relative movement of the dual-motion platform at the end needs to be realized by a complex transmission device, resulting in a high mass of the end moving parts, which is not conducive to improving the dynamic performance of the robot. Summary of the invention

[0004] The present invention is based on the above practical needs and provides a new type of parallel robot.

[0005] The technical solution of the parallel robot is implemented as follows:

[0006] A parallel robot comprises two bases, two branch chains symmetrically arranged in parallel between the two bases, and a moving platform connected to the ends of the two branch chains, each branch chain comprises a lead screw, a spline shaft, a moving seat, a joint and a connecting rod mechanism, the spline shaft and the lead screw in the lead screw are all supported to rotate in the same direction between the two bases, the joint keyway is fitted on the spline shaft, the moving seat is clearance-fitted on the spline shaft and is fixedly connected to the nut in the lead screw, the connecting rod mechanism is a parallelogram rod group structure, which is hinged on the moving seat and connected to the joint, a horizontally arranged connecting seat is hinged at the end of the connecting rod mechanism, a rotating shaft is arranged on the connecting seat in the vertical direction, and the moving platform is hinged on the rotating shafts on the connecting seats of the two branch chains.

[0007] Preferably, the connecting rod mechanism comprises a driving unit of a parallelogram rod group structure, the driving unit comprises a driving arm and a linkage arm, the head end of the driving arm is fixedly connected to the joint, and the head end of the linkage arm is hinged on the moving seat.

[0008] Preferably, the connecting rod mechanism also includes a driven unit of a parallelogram rod group structure, an elbow bracket is arranged between the driving unit and the driven unit, the driven unit includes a main driven rod and a secondary driven rod, the end of the driving arm, the end of the linkage arm, the head end of the main driven rod, and the head end of the secondary driven rod are all hinged on the elbow bracket, and the end of the main driven rod and the end of the secondary driven rod are both hinged on the connecting seat.

[0009] Preferably, the auxiliary driven rod comprises a first auxiliary driven rod and a second auxiliary driven rod, and a connecting rod is provided between the first auxiliary driven rod and the second auxiliary driven rod.

[0010] Preferably, a bearing is arranged in the through hole of the movable seat sleeve passing through the spline shaft, and the joint is arranged in the bearing.

[0011] Preferably, the screw rod in each branch chain is arranged directly above the spline shaft.

[0012] Preferably, a first motor connected to the screw shaft and a second motor connected to the spline shaft are arranged on the base.

[0013] The parallel robot is provided with two parallel branches, each of which is provided with a connecting rod mechanism of a parallelogram rod group structure. The parallel robot drives the screw and spline shaft on the two branches to rotate through an external motor. With the external motor speed and steering configuration, the parallel robot can have four-degree-of-freedom motion ability and achieve the technical effects of three-dimensional translation and one-dimensional rotation in space. The parallel robot is a single-platform form with a simple structure and low cost. It does not contain a complex transmission device, the moving parts are light in weight, the inertia of the movement is small, it is easy to achieve high-speed and high-acceleration dynamic performance, and the movement accuracy and stability are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 This is a schematic diagram of the structure of the parallel robot;

[0016] Figure 2 This is a schematic diagram of the branch chain structure of the parallel robot.

[0017] Description of reference numerals:

[0018] In the figure: 1. base, 2. first motor, 3. second motor, 4. lead screw, 5. spline shaft, 6. moving seat, 7. driving unit, 71. driving arm, 72. linkage arm, 8. elbow bracket, 9. driven unit, 91. main driven rod, 92. first secondary driven rod, 93. second secondary driven rod, 94. connecting rod, 10. connecting seat, 11. rotating shaft, 12. moving platform, 13. joint. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0020] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0021] The parallel robot, such as Figure 1 , 2 As shown, it includes two bases 1, two branch chains symmetrically arranged in parallel between the two bases 1, and a moving platform 12 connected to the ends of the two branch chains. The actuator is arranged on the moving platform 12, and different actuators can be replaced according to actual needs. Each branch chain includes a screw, a spline shaft 5, a moving seat 6, a joint 13 and a connecting rod mechanism. The spline shaft 5 and the screw 4 in the screw are all supported to rotate in the same direction between the two bases 1. The keyway of the joint 13 is sleeved on the spline shaft 5. The joint 13 can slide along the axis of the spline shaft 5 and rotate synchronously with the spline shaft 5. The moving seat 6 is sleeved on the spline shaft 5 with a clearance fit and is fixedly connected to the nut in the screw. The connecting rod mechanism is a parallelogram rod group structure, which is hinged on the moving seat 6 and connected to the joint 13. A horizontally arranged connecting seat 10 is hinged at the end of the connecting rod mechanism. A rotating shaft 11 is arranged on the connecting seat 10 in the vertical direction. The moving platform 12 is hinged on the rotating shaft 11 on the connecting seats 10 of the two branch chains.

[0022] The parallel robot is provided with two parallel branches, and the branches are provided with a connecting rod mechanism of a parallelogram rod group structure. During operation, the external motor drives the screws 4 on the two branches to rotate synchronously, so that the moving seats 6 on the two parallel branches keep moving synchronously. The moving seat 6 moves along the axis of the screw 4 driven by the nut, and the connecting rod mechanism moves synchronously therewith, driving the moving platform 12 to achieve a translational freedom in the same direction as the axis of the screw 4. During the above movement process, since the connecting rod mechanism is also connected to the joint 13 at the same time, the joint 13 also moves synchronously therewith under rigid linkage. During operation, the external motor drives the spline shafts 5 on the two branches to rotate in coordination, and the joint 13 rotates accordingly, and the joint 13 drives the connecting rod mechanism to rotate. Under the joint action of the connecting rod mechanism on the two branches, the moving platform 12 can also achieve a translational freedom perpendicular to the axis of the screw 4 in the horizontal plane, and a translational freedom perpendicular to the axis of the screw 4 in the vertical plane. During operation, the external motor drives the screw rods 4 on the two branches to rotate asynchronously, so that the moving seats 6 on the two parallel branches can keep moving asynchronously, and then the moving platform 12 connected between the two branches can also achieve a degree of rotational freedom around the vertical direction. That is, by driving the screw rods 4 and spline shafts 5 on the two branches to rotate through the external motor, combined with the external motor speed and steering configuration, the parallel robot can have four-degree-of-freedom motion capability and achieve the technical effects of three-dimensional translation and one-dimensional rotation in space.

[0023] The parallel robot is a single-platform robot with a simple structure and low cost. It does not contain a complex transmission device. The moving parts are lightweight and have small inertia. It is easy to achieve high-speed and high-acceleration dynamic performance, and has high motion accuracy and stability.

[0024] In the parallel robot, the specific structure of the connecting rod mechanism is as follows: Figure 2 As shown, the driving unit 7 includes a parallelogram rod group structure, and the driving unit 7 includes a driving arm 71 and a linkage arm 72. The front end of the driving arm 71 is fixedly connected to the joint 13, and the front end of the linkage arm 72 is hinged on the moving seat 6.

[0025] Furthermore, the connecting rod mechanism also includes a driven unit 9 of a parallelogram rod group structure, an elbow bracket 8 is arranged between the driving unit 7 and the driven unit 9, the driven unit 9 includes a main driven rod 91 and a secondary driven rod, the end of the driving arm 71, the end of the linkage arm 72, the head end of the main driven rod 91, and the head end of the secondary driven rod are all hinged on the elbow bracket 8, and the end of the main driven rod 91 and the end of the secondary driven rod are both hinged on the connecting seat 10.

[0026] In order to achieve a stable connection to the connection base 10, the secondary driven rod in the driven unit 9 includes a first secondary driven rod 92 and a second secondary driven rod 93, and a connecting rod 94 is arranged between the first secondary driven rod 92 and the second secondary driven rod 93. The connection base 10 is connected to the driven unit 9 through three hinge points, and the stability is more excellent.

[0027] In this parallel robot, the joint 13 and the moving seat 6 are kept moving synchronously only through the rigid linkage of the connecting rod mechanism, and the stability and accuracy are not good. In order to increase the tightness of the connection between the joint 13 and the moving seat 6, increase stability and improve the movement accuracy, a bearing is provided in the through hole of the moving seat 6 through the spline shaft 5, and the joint 13 is arranged in the bearing. The outer ring of the bearing is fixedly connected to the moving seat 6, and the inner ring of the bearing is fixedly connected to the joint 13. The keyway of the joint 13 is fitted on the spline shaft 5. In order to facilitate the connection between the joint 13 and the connecting rod mechanism, the joint 13 includes two parts, one part is located in the through hole of the moving seat 6 and is connected to the inner ring of the bearing, and the other part is located outside the moving seat 6 and is connected to the connecting rod mechanism.

[0028] In the present parallel robot, in the specific arrangement, two parallel branches are arranged side by side between two bases 1, and the screw rod 4 in each branch is arranged directly above the spline shaft 5, which can increase the compactness of the structure of the parallel robot and reduce the equipment footprint.

[0029] In the parallel robot, the base 1 is provided with a first motor 2 axially coupled to the screw rod 4 and a second motor 3 axially coupled to the spline shaft 5. The second motor 3 can be a motor with a self-contained speed reduction mechanism. The first motor 2 and the second motor 3 are both arranged on the base 1. The drive motor is fixedly arranged and will not move with the moving parts, thereby reducing the mass of the moving parts and improving the dynamic performance of the manipulator.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A parallel robot, characterized in that: The invention comprises two bases (1), two branch chains symmetrically arranged in parallel between the two bases (1), and a moving platform (12) connected to the ends of the two branch chains. Each branch chain comprises a lead screw, a spline shaft (5), a moving seat (6), a joint (13) and a connecting rod mechanism. The spline shaft (5) and the lead screw (4) in the lead screw are supported to rotate in the same direction between the two bases (1). The moving seat (6) is sleeved on the spline shaft (5) with clearance fit and is fixedly connected to a nut in the lead screw. A bearing is arranged in a through hole of the moving seat (6) which is sleeved through the spline shaft (5). The joint (13) is arranged in the bearing. The outer ring of the bearing is fixedly connected to the moving seat (6). The bearing inner ring is fixedly connected to the joint (13), the keyway of the joint (13) is sleeved on the spline shaft (5), the connecting rod mechanism is a parallelogram rod group structure, which is hinged on the moving seat (6) and connected to the joint (13), the end of the connecting rod mechanism is hinged with a horizontally arranged connecting seat (10), a rotating shaft (11) is arranged on the connecting seat (10) in the vertical direction, the moving platform (12) is hinged on the rotating shaft (11) on the two branch chain connecting seats (10), and the base (1) is provided with a first motor (2) axially connected to the screw rod (4) and a second motor (3) axially connected to the spline shaft (5).

2. The parallel robot according to claim 1, characterized in that: The connecting rod mechanism comprises a driving unit (7) of a parallelogram rod group structure, the driving unit (7) comprising a driving arm (71) and a linkage arm (72), the front end of the driving arm (71) is fixedly connected to the joint (13), and the front end of the linkage arm (72) is hinged on the moving seat (6).

3. The parallel robot according to claim 2, characterized in that: The connecting rod mechanism also includes a driven unit (9) of a parallelogram rod group structure, a toggle bracket (8) is arranged between the driving unit (7) and the driven unit (9), the driven unit (9) includes a main driven rod (91) and a secondary driven rod, the end of the driving arm (71), the end of the linkage arm (72), the head end of the main driven rod (91), and the head end of the secondary driven rod are all hinged on the toggle bracket (8), and the end of the main driven rod (91) and the end of the secondary driven rod are all hinged on the connecting seat (10).

4. The parallel robot according to claim 3, characterized in that: The auxiliary driven rod comprises a first auxiliary driven rod (92) and a second auxiliary driven rod (93), and a connecting rod (94) is arranged between the first auxiliary driven rod (92) and the second auxiliary driven rod (93).

5. The parallel robot according to claim 1, characterized in that: The screw rod (4) in each branch chain is arranged directly above the spline shaft (5).

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