CN104029212B - Three Degree Of Freedom is external turns heart rotating machinery wrist - Google Patents

Abstract

A kind of Three Degree Of Freedom of Industrial Robot Technology field is external turns heart rotating machinery wrist, comprise: upper moving platform, roll with upper moving platform the lower moving platform that is connected and rolling the pedestal be connected with lower moving platform, the side of upper moving platform is provided with the one-level track contacted with lower moving platform, and on lower moving platform, corresponding described one-level track is provided with driving mechanism; The side of lower moving platform is provided with the driving mechanism of secondary track and the corresponding secondary track contacted with pedestal, makes moving platform realize the rotation of Three Degree Of Freedom; Apparatus of the present invention turn the barycenter place that the heart is positioned at held workpiece, there is the rotational freedom in three directions.

Description

Three-degree-of-freedom external-center rotating mechanical wrist

technical field

The invention relates to a mechanism in the technical field of industrial robots, in particular to a mechanism for grabbing a workpiece and rotating around the center of mass of the workpiece in a large range, and can cooperate with a mechanical arm to grab the workpiece and adjust its pose. A three-degree-of-freedom mechanical wrist that rotates the heart outside the body.

Background technique

The three-degree-of-freedom rotating mechanism is widely used in various fields. At present, the spherical three-degree-of-freedom parallel mechanism and the ordinary parallel mechanism are widely used. In the prior art, there is a three-degree-of-freedom spherical parallel mechanism bionic eye, which connects the end with a fixed platform through three branches, and can move in a conical space with a half-cone angle of 45 degrees. But the turning range is small. There is also a three-degree-of-freedom rotating mechanism, which connects the dynamic platform and the static platform through three branch chains to realize the movement in a 60-degree semi-cone. The center of rotation of this mechanism is located on the inner side of the mechanism. Based on the above, the center of rotation of the current three-degree-of-freedom rotating mechanism is mostly located inside the mechanism, and the rotation range is small, which is difficult to meet the needs of the industry.

After searching the prior art, it was found that Chinese Patent Document No. CN103753522A was published (announced) on 2014.04.30, which disclosed a two-degree-of-freedom rotating manipulator, including: an upper moving platform, a lower moving platform and a fixed Platform, wherein: between the upper and lower moving platforms and between the lower moving platform and the fixed platform are rollingly connected by two sets of arc-shaped constrained roller sets; in addition, the lower moving platform and the upper moving platform are connected by a link mechanism The moving platform is connected with the fixed platform through a screw nut. However, there are too many rollers in the load-bearing parts of this technology, which requires high installation accuracy to work, and it is difficult to meet the needs of industrial development at this stage.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention proposes a three-degree-of-freedom external center-rotating mechanical wrist, whose center of rotation is located at the center of mass of the workpiece held, and has rotational degrees of freedom in three directions.

The present invention is realized through the following technical proposals. The present invention includes: an upper moving platform, a lower moving platform rollingly connected with the upper moving platform, and a base rollingly connected with the upper moving platform, wherein: one side of the upper moving platform is provided with The primary track in contact with the base is provided with a driving mechanism corresponding to the primary track; one side of the lower moving platform is provided with a secondary track in contact with the upper moving platform and a driving mechanism corresponding to the secondary track, so that the lower The moving platform realizes the rotation of three degrees of freedom.

The drive mechanism may be, but not limited to, a motor-gear combination or a screw-nut combination.

The base is connected with the mechanical arm to realize a complete revolution, which is the first of three revolutions.

The rolling directions of the primary track and the secondary track are perpendicular to each other, and the virtual centers of the two coincide.

The other side of the lower moving platform is connected to the workpiece, and its relative position to the workpiece remains unchanged during the movement, so that the virtual center of the primary track and the secondary track is located in the workpiece and coincides with the center of mass of the workpiece.

When the driving mechanism corresponding to the first-level track adopts a screw nut combination, the nut in the screw nut combination and the upper moving platform form a revolving pair, and the screw mounting frame in the screw nut combination is also connected to the base. A revolving pair is formed. When the lead screw pushes the nut to move, the nut and the upper moving platform rotate around the virtual center of the circle, and the relative rotation between the lead screw mounting bracket and the base changes the pose of the lead screw.

technical effect

Compared with the prior art, the rotation center of the present invention is on the outside of the manipulator, which is located at the center of mass of the workpiece, so the moment of inertia is small and the requirements for the motor are reduced;

When working, when it is necessary to rotate around the first virtual axis, the motor on the gear mechanism is locked, the motor on the lead screw rotates, and the nut is pushed to move, while the lead screw automatically adjusts its posture, and the lead screw mounting bracket rotates relative to the base; When needing to rotate around the second virtual axis, the motor on the leading screw is locked, and at this moment, the upper moving platform and the base have no relative motion, and the upper motor of the gear mechanism rotates to push the lower moving platform and the workpiece to rotate.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the invention;

Fig. 2 is a partially enlarged schematic diagram of Fig. 1;

In the figure: 1 base, 2 upper moving platform track, 3 lower moving platform track, 4 slider installation position, 5 first virtual axis, 6 second virtual axis, 7 upper moving platform, 8 gear mechanism, 9 lower moving platform , 10 workpieces, 11 lower moving platform slider installation position, 12 lead screw mounting frame, 13 nuts, 14 lead screws.

detailed description

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

As shown in Figure 1, this embodiment includes: a lower moving platform 9, an upper moving platform 7 and a base 1, wherein the lower moving platform 9 and the upper moving platform 7 are connected by a track 3 and a slider 4 as passive constraints, and are connected by a gear The mechanism 8 is used as the drive; the upper moving platform 7 and the base 1 are connected by the track 2 and the slider 11 as passive constraints, and the screw and nut mechanism is used as the drive.

Described lead screw and nut mechanism is as shown in Figure 2, and lead screw installation frame 12 and lead screw 14 are connected and fixed on the base 1 by rotating pair, nut 13 and upper moving platform 7 are connected by rotating pair, pass lead screw The rotation of 14 pushes the nut 13 to rotate around the 5 first imaginary axis

The rolling directions of the two tracks 2 and 3 are perpendicular to each other and their virtual centers coincide.

There is a gripping mechanism on the lower moving platform 9 for grabbing the workpiece 10 , and the virtual center of circle is located in the workpiece 10 and coincides with the center of mass of the workpiece 10 .

The base 1 is fixedly connected with the mechanical arm, and the rotation of the arm drives the manipulator to realize a full-circle rotary motion.

During work, the base 1 is fixed, and when it needs to rotate around the above-mentioned first virtual axis 5, the motor on the gear 8 is locked, the motor on the lead screw 14 rotates, and the lead screw 14 pushes the nut 13 to move forward, but due to the track 2 and Due to the constraints of the slider 11, the upper moving platform 7 can only rotate along the first virtual axis 5.

When needing to rotate along the second virtual shaft 6, the motor on the leading screw 14 is locked, the motor on the gear mechanism 8 rotates, a rack is arranged on the moving platform 9, and the gear 8 and the rack on the lower moving platform 9 cooperate to move, but Under the constraints of the track 3 and the slider 4, the lower moving platform 9 makes a rotary motion around the second virtual axis 6, driving the workpiece 10 to rotate.

This device designs the center of rotation on the outside of the manipulator, that is, at the center of mass of the workpiece, so that the overall moment of inertia is small, and the requirements for the motor are greatly reduced; the arc track is used as a passive constraint, and the gear mechanism in the body is used at the same time. A large turning range is obtained in a small size.

Claims (3)

1. A three-degree-of-freedom external rotating mechanical wrist, characterized in that it comprises: an upper moving platform, a lower moving platform rollingly connected with the upper moving platform, and a base rollingly connected with the lower moving platform, wherein: the upper moving platform One side of the lower moving platform is provided with a first-level track that is in contact with the lower moving platform, and a drive mechanism is provided on the lower moving platform corresponding to the first-level track; the base is connected with the mechanical arm to achieve a full circle of rotation, that is, one degree of freedom ; One side of the lower moving platform is provided with a secondary track in contact with the base and a driving mechanism corresponding to the secondary track, so that the upper moving platform can achieve three-degree-of-freedom rotation; the rolling directions of the first-level track and the second-level track are perpendicular to each other And the virtual centers of the two coincide; The rotation center of the three degrees of freedom is located outside the mechanical wrist; The other side of the upper moving platform is connected to the workpiece, and its relative position to the workpiece remains unchanged during the movement, so that the virtual center of the primary track and the secondary track is located in the workpiece and coincides with the center of mass of the workpiece. 2. The three-degree-of-freedom external-center rotating mechanical wrist according to claim 1, wherein the drive mechanism adopts a motor-gear combination or a screw-nut combination. 3. The three-degree-of-freedom external-center rotating mechanical wrist according to claim 2, characterized in that, when the driving mechanism corresponding to the secondary track adopts a combination of screw and nut, the nut in the combination of screw and nut is connected with the lower The rotating pair is formed between the moving platforms, and the screw mounting bracket in the screw nut combination is connected with the base to form a rotating pair. When the screw pushes the nut to move, the nut and the lower moving platform rotate around the virtual center of the circle, and the screw is installed The relative rotation between the frame and the base changes the pose of the lead screw.