CN103737207A - Parallel-serial welding robot mechanism with six degrees of freedom - Google Patents

Abstract

The invention relates to a six-degree-of-freedom hybrid welding robot mechanism, including a waist rotation mechanism, a shoulder swing mechanism, an elbow rotation mechanism, a forearm rotation mechanism, a wrist rotation mechanism, a welding torch holder rotation mechanism, a machine base and a rotation platform; The swing mechanism and the elbow rotation mechanism form a parallel mechanism to realize the two-dimensional translation of the plane, and deliver the forearm executive end welding torch holder to the predetermined area; the full circle rotation of the rotating platform realizes the position adjustment of the executive end within the space range, and obtains better Large working space; the forearm torsion mechanism, the wrist rotation mechanism and the torch holder rotation mechanism form a series mechanism, and the three-dimensional rotation realizes the adjustment of the welding torch posture. The invention can flexibly and simply send the welding torch to work at different points in the space, obtain better dynamic performance, reduce the bearing load of the shoulder joint, and achieve high precision, high reliability and excellent characteristics of easy maintenance.

Description

A six-degree-of-freedom hybrid welding robot mechanism

technical field

The invention relates to the field of industrial robots, in particular to a six-degree-of-freedom hybrid welding robot mechanism.

Background technique

Industrial robots are multi-joint manipulators or robots with multiple degrees of freedom for the industrial field. An industrial robot is a machine device that performs work automatically, and is a machine that realizes various functions by its own power and control capabilities. China will become the world's largest consumer of industrial robots by 2014. According to experts, in 2011, China's industrial robot sales increased by 51% year-on-year. In the next three years, the compound growth rate of China's industrial robot market will reach 30%. China may become the world's largest robot demand market. Due to the rapid development of modern computer technology and the continuous maturity of multi-axis motion control technology, the cost of industrial robots has gradually decreased, and has now entered a stage of explosive growth. As a kind of industrial robot, welding robot occupies a large proportion. The welding robots in the world are basically articulated robots, and most of them have six axes, three of which will send the end-mounting tools to the space accessible position, and the other three axes will realize the spatial attitude adjustment of the end-end welding tools . The traditional articulated welding robot installs the motor at the joint, which makes the robot arm appear cumbersome, and has disadvantages such as large moment of inertia, poor stiffness, and large cumulative error. The dynamic performance of the mechanism is poor, and it is difficult to meet the increasingly high-speed and high-precision requirements. The series mechanism has better kinematic performance in terms of mechanism design, but the dynamic performance is lower; compared with the series robot, the parallel mechanism has no cumulative error and high precision, and the driving device can be placed on or close to the fixed platform. The position of the moving part is light, the speed is high, the dynamic response is good, the structure is compact, the rigidity is high, and the carrying capacity is large. The space is often small, and it is generally used in driving simulation platforms, radar antenna bases, CNC lathes and other fields, and it is difficult to apply to welding robots and other fields that require a large working space. Moreover, the waist joints of existing robots not only support the weight of the entire robot, but also bear the impact brought by the movement of the entire robot, which has a high failure rate, poor reliability, short trouble-free running time, and is easy to cause large joint errors. The accuracy of the robot is greatly affected. Due to these shortcomings, the existing robot structure is difficult to take into account the characteristics of operating flexibility and high precision, and it is difficult to meet the operating requirements of large working space, high precision, and high reliability. a bottleneck. Therefore, how to meet the structural requirements of large-scale robots under the premise of ensuring the flexibility, high precision and high reliability of robot operations has become an important issue discussed by many scholars and institutions.

Contents of the invention

The purpose of the present invention is to provide a welding robot mechanism of a hybrid mechanism in order to overcome the problems existing in the prior art, which integrates the respective advantages of the serial mechanism and the parallel mechanism to ensure the flexibility, high precision and high reliability of the robot operation, Under the premise of giving full play to the advantages of the series-parallel mechanism, the motor should be placed on the machine base as much as possible or the motor should be reasonably arranged near the rotation axis of the entire circumference, that is, the rotation radius of the motor can be reduced as much as possible, and the shoulder of the robot can be greatly improved. The reliability of the joints reduces maintenance costs and achieves better dynamic performance of the robot.

The present invention realizes the above object through the following technical solutions:

A six-degree-of-freedom hybrid welding robot mechanism, including a waist rotation mechanism, a shoulder swing mechanism, an elbow rotation mechanism, a forearm rotation mechanism, a wrist rotation mechanism, a welding torch holder rotation mechanism, a machine base and a rotation platform;

The waist turning mechanism is installed on the machine base by the first rotating pair through the rotating platform, and the first rotating pair is driven by the first servo motor;

The shoulder swing mechanism includes a rotating platform, a first active rod, a first connecting rod and a second connecting rod. The rotating platform and the first active rod are connected by a second rotating pair, and the first active rod and the first connecting rod are connected by a third connecting rod. The rotating pair is connected, the first connecting rod and the second connecting rod are connected by the fourth rotating pair, the second connecting rod and the rotating platform are connected by the fifth rotating pair, and the first active rod is driven by the second servo motor;

The toggle mechanism includes a second active rod, a third connecting rod and a fourth connecting rod, the second active rod and the second connecting rod are connected by the sixth rotating pair, and the second active rod and the third connecting rod are connected by the seventh rotating pair. Secondary connection, the third connecting rod and the fourth connecting rod are connected by the eighth rotating pair, the fourth connecting rod and the second connecting rod are connected by the ninth rotating pair; the second active rod is driven by the third servo motor;

The forearm twisting mechanism, the wrist turning mechanism and the welding torch seat turning mechanism form a three-dimensional turning mechanism. The forearm twisting mechanism is connected by the forearm and the fourth connecting rod through the tenth rotating pair, and is driven by the fourth servo motor installed on the fourth connecting rod. The wrist rotation mechanism is connected by the forearm and the wrist through the eleventh rotation pair, driven by the fifth servo motor installed on the forearm; the welding torch holder rotation mechanism is connected by the wrist and the welding torch holder through the twelfth rotation pair, and is installed Driven by a sixth servo motor on the wrist.

The axis of the first rotary pair is perpendicular to the machine base, the second rotary pair, the third rotary pair, the fourth rotary pair, the fifth rotary pair, the sixth rotary pair, the seventh rotary pair, the eighth rotary pair and the ninth rotary pair The axes of the rotating pairs are parallel to each other, the fifth rotating pair is coaxial with the sixth rotating pair, the axes of the tenth rotating pair and the ninth rotating pair are perpendicular to each other, the axes of the eleventh rotating pair and the ninth rotating pair are perpendicular to each other, and the axes of the twelfth rotating pair The axes of the auxiliary and the eleventh rotating auxiliary are perpendicular to each other.

The invention realizes the whole circle rotation of the waist through the waist rotation mechanism; the two-degree-of-freedom parallel mechanism composed of the shoulder swing mechanism and the elbow rotation mechanism realizes two-dimensional translation, which are respectively driven by motors installed on the rotation platform; The three mutually orthogonal rotation axes connected by the rotary mechanism and the rotary mechanism of the welding torch holder are independently driven by three motors, which realizes the three-degree-of-freedom attitude adjustment of the welding torch at the execution end. Compared with the prior art, the present invention has the following outstanding advantages:

1. The hybrid mechanism is adopted, which has the advantages of high rigidity of the parallel mechanism and large working space of the series mechanism. The driving device is placed on the machine base as much as possible, which reduces the load of the arm rod and the moment of inertia of the whole machine. Light weight, small cumulative error, and good dynamic performance. The support point of the boom is led out through a small parallelogram mechanism and driven by a motor alone, which reduces the load capacity of the motor shaft and is conducive to the improvement of precision;

2. An additional load-bearing hinge point is added through the parallelogram mechanism, which improves the shortcomings of the traditional mechanism, such as poor load-carrying capacity, low precision, inconvenient maintenance, and low reliability because all loads are applied to the same shoulder motor shaft. ;

3. Reasonably arrange the driving device of the series part of the mechanism, improve the balance performance of the overall mechanism, and further improve the dynamic performance of the mechanism;

4. The structure is simple, which is convenient for the solution of forward and reverse kinematics, trajectory planning, error compensation, and convenient and precise control. In addition, different devices installed at the end can realize different industrial uses, such as palletizing, cutting, assembling, spraying and handling, etc.

Description of drawings

Fig. 1 is a structural schematic diagram of the hybrid welding robot mechanism.

Fig. 2 is a schematic diagram of the shoulder swing mechanism of the hybrid welding robot mechanism.

Fig. 3 is a schematic diagram of the elbow turning mechanism of the hybrid welding robot mechanism.

Fig. 4 is a schematic diagram of the forearm twisting mechanism, the wrist turning mechanism and the welding torch holder turning mechanism of the hybrid welding robot mechanism.

Fig. 5 is a schematic diagram of the first working state of the hybrid welding robot mechanism.

Fig. 6 is a schematic diagram of the second working state of the hybrid welding robot mechanism.

Fig. 7 is a schematic diagram of the third working state of the hybrid welding robot mechanism.

Fig. 8 is a schematic diagram of the fourth working state of the hybrid welding robot mechanism.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Referring to Figures 1, 2, 3 and 4, a six-degree-of-freedom hybrid welding robot mechanism consists of a waist rotation mechanism, a shoulder swing mechanism, an elbow rotation mechanism, a forearm rotation mechanism, a wrist rotation mechanism, a welding torch holder rotation mechanism, and a machine base. 1 and a rotary platform 2 constitute.

Referring to Fig. 1, the waist turning mechanism of the mechanism is connected to the machine base 1 by the first rotating pair 12 through the rotating platform 2, and is driven by the first servo motor to realize the full-circle turning motion.

1 and 2, the shoulder swing mechanism is formed by connecting the rotating platform 2, the first active rod 3, the first connecting rod 4 and the second connecting rod 5. The first active rod 3 is connected with the rotating platform 2 through the second rotating pair 13, and the second rotating pair 13 is connected with the motor shaft of the second servo motor installed on the rotating platform 2, and the first active rod 3 is connected with the first connecting rod 4 The third connecting rod 4 is connected with the second connecting rod 5 through the fourth rotating pair 15 , and the second connecting rod 5 is connected with the rotating platform 2 through the fifth rotating pair 16 .

Referring to Figs. 1 and 3, the toggle mechanism is composed of a second active rod 6, a third connecting rod 7 and a fourth connecting rod 8. The second active rod 6 is connected with the rotary platform 2 by the sixth rotary pair 17, and the sixth rotary pair 17 is connected with the motor shaft of the third servo motor installed on the rotary platform 2, thereby driving the second active rod 6; The rod 7 is connected with the second active rod 6 through the seventh rotating pair 18, the other end of the third connecting rod 7 is connected with the fourth connecting rod 8 through the eighth rotating pair 19, and the fourth connecting rod 8 is connected with the second connecting rod 5 through A ninth revolute joint 20 is connected.

1 and 4, the forearm torsion mechanism, the wrist rotation mechanism and the welding torch seat rotation mechanism form a three-dimensional rotation mechanism. 8. Driven by the fourth servo motor on the front end, the installation position of the fourth servo motor is conducive to balancing the load on the front end of the forearm 9 to ensure good dynamic performance; the wrist rotation mechanism is composed of the forearm 9 and the wrist 10 through the eleventh rotation 22 connection, driven by the fifth servo motor installed on the forearm 9; the welding torch holder rotary mechanism is connected by the wrist 10 and the welding torch holder 11 through the twelfth rotating pair 23, driven by the sixth servo motor installed on the wrist , to realize the rotation of the welding torch.

The forearm torsion mechanism, the wrist rotation mechanism and the welding torch holder rotation mechanism are driven independently by three servo motors, which realize three-dimensional rotation, and then realize the adjustment of the welding torch posture.

Referring to Figures 1, 5, 6, 7, and 8, a six-degree-of-freedom hybrid welding robot mechanism realizes two-dimensional translation of the plane through a mechanism composed of a shoulder swing mechanism and an elbow rotation mechanism, and the forearm executes the terminal welding torch holder Delivery to the predetermined area; the full circle rotation of the rotating platform realizes the position adjustment of the execution end within the space range, and obtains a larger working space; the three-dimensional rotation of the forearm twisting mechanism, the wrist turning mechanism and the welding torch holder turning mechanism realizes the welding torch posture adjustment. The above mechanism characteristics realize various positions and postures of the mechanism as shown in Figure 5-Figure 8, flexibly and simply send the welding torch to work at different points in space, and obtain better dynamic performance, reduce the bearing load of the shoulder joint, and achieve Excellent characteristics of high precision, high reliability and easy maintenance.

Claims (2)

1. A six-degree-of-freedom hybrid welding robot mechanism, comprising a waist rotation mechanism, a shoulder swing mechanism, an elbow rotation mechanism, a forearm rotation mechanism, a wrist rotation mechanism, a welding torch holder rotation mechanism, a machine base and a rotary platform; it is characterized in that: The waist turning mechanism is installed on the machine base by the first rotating pair through the rotating platform, and the first rotating pair is driven by the first servo motor; The shoulder swing mechanism includes a rotating platform, a first active rod, a first connecting rod and a second connecting rod. The rotating platform and the first active rod are connected by a second rotating pair, and the first active rod and the first connecting rod are connected by a third connecting rod. The rotating pair is connected, the first connecting rod and the second connecting rod are connected by the fourth rotating pair, the second connecting rod and the rotating platform are connected by the fifth rotating pair, and the first active rod is driven by the second servo motor; The toggle mechanism includes a second active rod, a third connecting rod and a fourth connecting rod, the second active rod and the second connecting rod are connected by the sixth rotating pair, and the second active rod and the third connecting rod are connected by the seventh rotating pair. Secondary connection, the third connecting rod and the fourth connecting rod are connected by the eighth rotating pair, the fourth connecting rod and the second connecting rod are connected by the ninth rotating pair; the second active rod is driven by the third servo motor; The forearm twisting mechanism, the wrist turning mechanism and the welding torch seat turning mechanism form a three-dimensional turning mechanism. The forearm twisting mechanism is connected by the forearm and the fourth connecting rod through the tenth rotating pair, and is driven by the fourth servo motor installed on the fourth connecting rod. The wrist rotation mechanism is connected by the forearm and the wrist through the eleventh rotation pair, driven by the fifth servo motor installed on the forearm; the welding torch holder rotation mechanism is connected by the wrist and the welding torch holder through the twelfth rotation pair, and is installed Driven by a sixth servo motor on the wrist. 2. The hybrid welding robot mechanism according to claim 1, wherein the axis of the first rotating pair is perpendicular to the base, and the second rotating pair, the third rotating pair, the fourth rotating pair, and the fifth rotating pair The axes of the first, sixth, seventh, eighth and ninth revolving pairs are parallel to each other, the fifth and sixth revolving pairs are coaxial, and the axes of the tenth and ninth revolving pairs are perpendicular to each other , the axes of the eleventh revolving pair and the ninth revolving pair are perpendicular to each other, and the axes of the twelfth revolving pair and the eleventh revolving pair are perpendicular to each other.

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