CN113459071A

CN113459071A - Three-degree-of-freedom parallel robot

Info

Publication number: CN113459071A
Application number: CN202110791047.4A
Authority: CN
Inventors: 万俊; 葛敏; 张兰春
Original assignee: Jiangsu University of Technology
Current assignee: Jiangsu University of Technology
Priority date: 2021-07-13
Filing date: 2021-07-13
Publication date: 2021-10-01

Abstract

The invention provides a three-degree-of-freedom parallel robot which comprises a fixed platform, a movable platform and three groups of transmission rod assemblies, wherein each group of transmission rod assemblies is correspondingly provided with a driving assembly, each driving assembly comprises a ball screw, a screw nut is arranged on the ball screw, each transmission rod assembly comprises a driving arm, an L-shaped transmission arm and a connecting piece, one end of each driving arm is hinged to the outer wall surface of the screw nut, the other end of each driving arm is hinged to the upper end of the corresponding L-shaped transmission arm, the L-shaped corner of each L-shaped transmission arm is hinged to the fixed platform, the driving arms are parallel to the axis of the hinged point on the corresponding L-shaped transmission arm, the upper end of each connecting piece is in universal connection with the lower end of the corresponding L-shaped transmission arm, and the lower end of each connecting piece is in universal connection with the movable platform. According to the three-degree-of-freedom parallel robot, the ball screw, the screw nut, the driving arm and the L-shaped transmission arm are matched to form the crank-link mechanism driving moving platform, and the ball screw is high in precision, reversibility and efficiency, so that the running reliability and precision of the parallel robot can be guaranteed.

Description

Three-degree-of-freedom parallel robot

Technical Field

The invention relates to the technical field of robots, in particular to a three-degree-of-freedom parallel robot.

Background

The DELTA parallel robot is also called a triangular robot and mainly comprises a driving motor, a main mechanical arm, an auxiliary mechanical arm, a fixed platform, a movable platform, a claw tool and the like, and the whole appearance of the DELTA parallel robot is similar to three inverted triangles, so the DELTA parallel robot is named. The DELTA robot is a typical spatial three-degree-of-freedom mechanical arm mechanism, and has the characteristics of compact structure, light weight, high positioning precision, high movement speed and the like because the driving groups are uniformly distributed on the fixed frame, so that the DELTA robot is suitable for occasions such as carrying, processing and assembling light objects such as food, medicines, electronic products and the like.

Because the parallel robot has no accumulated error, the precision is high. The parallel robot can place the driver on the static platform, thus not only reducing the weight of the moving part, but also improving the running speed. The parallel robot mechanism is relatively compact in structure, good in rigidity and large in bearing capacity. At present, because the output torque of a motor is smaller, the running requirements of a robot can be met only by reducing the rotating speed and improving the output torque of a common serial robot and a common parallel robot by using a speed reducer, but the gear of the speed reducer is easy to wear or damage, the overall motion precision is reduced, and finally the position and posture precision of a movable platform is difficult to guarantee.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects that in the prior art, a speed reducer is utilized to reduce the rotating speed and improve the output torque of a parallel robot, but gears of the speed reducer are easy to wear or damage, so that the movement precision is reduced, and finally the position and posture precision of a movable platform is difficult to guarantee, the invention provides the three-degree-of-freedom parallel robot.

The technical scheme adopted for solving the technical problems is as follows: a three-degree-of-freedom parallel robot comprises a fixed platform, a movable platform and at least three groups of transmission rod assemblies, wherein each group of transmission rod assemblies is correspondingly provided with a driving assembly, each driving assembly comprises a ball screw rotationally connected with the fixed platform, the ball screw is in threaded connection with a screw nut, each ball screw is symmetrical along the center of the fixed platform, each transmission rod assembly comprises a driving arm, an L-shaped transmission arm and a connecting piece, one end of each driving arm is hinged to the outer wall surface of the screw nut, the other end of each driving arm is hinged to the upper end of the L-shaped transmission arm, the L-shaped corner of each L-shaped transmission arm is hinged to the fixed platform, the axes of hinged points of the driving arms and the L-shaped transmission arms are parallel, the upper end of each connecting piece is in universal connection with the lower end of the L-shaped transmission arm, and the lower end of each connecting piece is in universal connection with the movable platform, and each ball screw rotates along the axis to drive the movable platform to move along the directions of an X axis, a Y axis and a Z axis.

The ball screw, the screw nut, the driving arm and the L-shaped transmission arm are matched to form a crank-link mechanism, the ball screw rotates to drive the screw nut to do reciprocating linear motion to drive the driving arm, and the driving arm drives the L-shaped transmission arm to do rotary motion; the ball screw, the screw nut, the driving arm, the L-shaped transmission arm and the connecting piece form a driving branched chain, and the plurality of groups of driving branched chains are matched with each other to drive the movable platform, so that the precise work of the movable platform is realized.

Furthermore, the connecting piece includes two linking arms that are parallel to each other, two the linking arm symmetry is located L shape transmission arm both sides, the linking arm upper end with L shape transmission arm ball pivot is connected, the linking arm lower extreme with move the platform ball pivot and connect. The two connecting arms, the L-shaped transmission arm and the movable platform form a parallelogram structure, and the joints are connected through spherical hinges, so that the robot has better flexibility and higher rigidity, can realize large-angle deflection, and can be widely applied to the field of serial-parallel mechanical arms.

Furthermore, a plurality of springs are connected between the two connecting arms of the connecting piece. The clearance of the spherical hinge connection at the joint is eliminated through the spring.

Furthermore, the ball screw is in transmission connection with a servo motor. Each ball screw is controlled by one servo motor independently, and the servo motors are matched with each other, so that the moving platform can move accurately in the directions of an X axis, a Y axis and a Z axis.

Further, one or more kidney-shaped holes are formed in the driving arm and the L-shaped transmission arm. Therefore, the weight of the moving part can be reduced, the running speed can be improved, and the running reliability and precision of the parallel robot can be ensured.

The invention has the beneficial effects that: according to the three-degree-of-freedom parallel robot, the ball screw, the screw nut, the driving arm and the L-shaped transmission arm are matched to form the crank-link mechanism driving movable platform, a driving mode that the motor reducer drives the movable platform to work is replaced, and the ball screw is high in precision, reversibility and efficiency, so that the running reliability and precision of the parallel robot can be guaranteed.

Drawings

The invention is further illustrated by the following figures and examples.

FIG. 1 is a schematic structural diagram of a preferred embodiment of the present invention;

FIG. 2 is an enlarged schematic view of A of FIG. 1;

FIG. 3 is a top view of the preferred embodiment of the present invention;

fig. 4 is a schematic view of the connection between the movable platform and the connecting piece.

In the figure: 1. the device comprises a fixed platform, a movable platform, a ball screw, a screw nut, a driving arm, a servo motor, a connecting arm, a spring, a servo motor, a synchronous belt and a synchronous belt.

Detailed Description

The present invention will now be described in detail with reference to the accompanying drawings. This figure is a simplified schematic diagram, and merely illustrates the basic structure of the present invention in a schematic manner, and therefore it shows only the constitution related to the present invention.

As shown in fig. 1-4, the three-degree-of-freedom parallel robot of the present invention includes a fixed platform 1, a movable platform 2 and three sets of transmission rod assemblies, each set of transmission rod assembly is correspondingly provided with a driving assembly, the driving assembly includes a ball screw 3 rotatably connected with the fixed platform 1, the ball screw 3 is screwed with a screw nut 4, each ball screw 3 is symmetrical along the center of the fixed platform 1, the transmission rod assembly includes a driving arm 5, an L-shaped transmission arm 6 and a connecting piece 7, one end of the driving arm 5 is hinged with the outer wall surface of the screw nut 4, the other end of the driving arm 5 is hinged with the upper end of the L-shaped transmission arm 6, the L-shaped corner of the L-shaped transmission arm 6 is hinged with the fixed platform 1, the axes of the hinged points of the driving arm 5 and the L-shaped transmission arm 6 are parallel, the upper end of the connecting piece 7 is connected with the lower end of the L-shaped transmission arm 6 in a universal manner, the lower end of the connecting piece 7 is connected with the movable platform 2 in a universal mode, and each ball screw 3 rotates along the axis to drive the movable platform 2 to move along the directions of an X axis, a Y axis and a Z axis.

The connecting piece 7 comprises two connecting arms 701 which are parallel to each other, the two connecting arms 701 are symmetrically arranged on two sides of the L-shaped transmission arm 6, the upper end of each connecting arm 701 is connected with the corresponding L-shaped transmission arm 6 through a spherical hinge, and the lower end of each connecting arm 701 is connected with the corresponding movable platform 2 through a spherical hinge.

A plurality of springs 8 are connected between the two connecting arms 701 of the connecting piece 7.

The ball screw 3 is in transmission connection with a servo motor 9. A synchronous belt 10 is connected between the output end of the servo motor 9 and the input end of the ball screw 3.

One or more kidney-shaped holes are arranged on the driving arm 5 and the L-shaped transmission arm 6.

The working process is as follows:

the servo motor 9 drives the ball screw 3 to rotate, the ball screw 3 drives the screw nut 4 to do reciprocating linear motion, the screw nut 4 drives the driving arm 5 to move, the driving arm 5 drives the L-shaped driving arm 6 to rotate along a hinge joint between the L-shaped driving arm 6 and the static platform, the L-shaped driving arm 6 drives the two connecting arms 701, and finally the driving platform 2 is driven to move;

three servo motors 9 of group are respectively corotation or reversal certain number of turns, through the position of the lead screw nut 4 on controlling each ball 3, finally accurate control brake platform 2's spatial position.

Directions and references (e.g., up, down, left, right, etc.) may be used in the present disclosure only to aid in the description of features in the figures. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the claimed subject matter is defined only by the appended claims and equivalents thereof.

In light of the foregoing description of preferred embodiments in accordance with the invention, it is to be understood that numerous changes and modifications may be made by those skilled in the art without departing from the scope of the invention. The technical scope of the present invention is not limited to the contents of the specification, and must be determined according to the scope of the claims.

Claims

1. A three-degree-of-freedom parallel robot is characterized in that: the device comprises a fixed platform (1), a movable platform (2) and at least three groups of transmission rod assemblies, wherein each group of transmission rod assemblies is correspondingly provided with a driving assembly, each driving assembly comprises a ball screw (3) rotationally connected with the fixed platform (1), the ball screw (3) is in threaded connection with a screw nut (4), each ball screw (3) is symmetrical along the center of the fixed platform (1), each transmission rod assembly comprises a driving arm (5), an L-shaped transmission arm (6) and a connecting piece (7), one end of each driving arm (5) is hinged with the outer wall surface of the corresponding screw nut (4), the other end of each driving arm (5) is hinged with the upper end of the corresponding L-shaped transmission arm (6), the L-shaped corner of each L-shaped transmission arm (6) is hinged with the fixed platform (1), and the driving arms (5) and the hinge points on the corresponding L-shaped transmission arms (6) are parallel in axis, the upper end of the connecting piece (7) is in universal connection with the lower end of the L-shaped transmission arm (6), the lower end of the connecting piece (7) is in universal connection with the movable platform (2), and the ball screws (3) rotate along the axis to drive the movable platform (2) to move along the X-axis direction, the Y-axis direction and the Z-axis direction.

2. The three-degree-of-freedom parallel robot of claim 1, wherein: connecting piece (7) include two linking arms (701) that are parallel to each other, two linking arm (701) symmetry is located L shape transmission arm (6) both sides, linking arm (701) upper end with L shape transmission arm (6) ball pivot is connected, linking arm (701) lower extreme with move platform (2) ball pivot and connect.

3. The three-degree-of-freedom parallel robot of claim 2, wherein: a plurality of springs (8) are connected between the two connecting arms (701) of the connecting piece (7).

4. The three-degree-of-freedom parallel robot of claim 1, wherein: the ball screw (3) is in transmission connection with a servo motor (9).

5. The three-degree-of-freedom parallel robot of claim 1, wherein: one or more kidney-shaped holes are arranged on the driving arm (5) and the L-shaped transmission arm (6).