CN216505095U - Three-degree-of-freedom parallel main shaft head containing over-constrained redundant drive - Google Patents

Abstract

The invention relates to a three-degree-of-freedom parallel spindle head with over-constrained redundant drive, comprising a first moving platform, a second moving platform, a static platform, a first branch, a second branch, a third branch, a fourth Branch chain, the two ends of the first moving platform are connected with the static platform through the second branch chain and the fourth branch chain, the two ends of the second moving platform are connected with the static platform through the first branch chain and the third branch chain, and the first moving platform is connected with the second branch chain and the fourth branch chain. The middle part of the second moving platform is connected by the platform rotating pair, and finally a parallel mechanism with space two rotation and one translation motion capability is formed; the structure of each branch is exactly the same, including the rotating pair, the moving pair and the Hooke hinge, and the rotating pair is fixedly installed In the frame, the rotating pair is sleeved on the moving pair and is connected with the sliding part of the moving pair. One end of the Hook hinge is fixedly installed on one end of the fixed part of the moving pair, and the other end of the Hook hinge is connected and fixed with the corresponding moving platform. The design has a single kinematic branch type, no ball joints, with over constraints, redundant drives and a high degree of modularity.

Description

Three-DOF Parallel Spindle Head with Overconstrained Redundant Drive

technical field

The invention relates to a three-degree-of-freedom parallel spindle head with over-constrained redundant drive.

Background technique

In recent years, parallel robots have become a major research focus in the field of robotics due to their simple structure, easy control, and high stiffness, especially the three-degree-of-freedom parallel mechanism with two rotations and one translation (2R1T). With the 2R1T parallel mechanism as the main body, a large number of hybrid designs have emerged in series with x-y mobile platforms with two degrees of freedom. Among these parallel mechanisms with two rotations and one translation, compared with non-redundant driven parallel mechanisms, redundant driven parallel mechanisms have the advantages of eliminating singular points and improving mechanism rigidity and dexterity. Generally speaking, the parallel mechanism has two types of redundant drives: (1) adding a drive input to the passive joint that just drives the parallel operating head, so that the passive joint becomes the active joint; (2) adding one or more active motion branches To just drive the parallel operating head, but do not change the original degree of freedom of the mechanism. From the point of view of improving the stiffness performance of the mechanism, this kind of redundant drive parallel mechanism can not only meet the required motion form, but also improve the performance of the mechanism, so researchers have invested a lot of effort. Among the existing mechanisms, patent CN106965153 proposes a parallel machine tool body with redundant drive, and patent CN107127738A proposes a reconfigurable redundant drive generalized parallel mechanism with rigid-flexible hybrid line decoupling and variable stiffness. Among these types of mechanisms, the mechanism is more complex, and the number of moving components is large, the maintenance cost is high, and the operation is complicated and cumbersome.

SUMMARY OF THE INVENTION

The invention proposes a three-degree-of-freedom parallel spindle head with over-constrained redundant drive.

The solution adopted by the present invention to solve the technical problem is a three-degree-of-freedom parallel spindle head with over-constrained redundant drive, including a first moving platform, a second moving platform, a static platform, a first branch chain, and a second branch. chain, the third branch chain and the fourth branch chain, the two ends of the first moving platform and the static platform are connected by the second branch chain and the fourth branch chain, and the two ends of the second moving platform and the static platform are connected by the first branch chain and the third branch chain chain connection, the first moving platform and the middle part of the second moving platform are connected by the platform rotation pair, and finally form a parallel mechanism with the ability of two rotations and one translation in space;

The structure of each branch is exactly the same, including the rotating pair, the moving pair and the Hooke hinge. The rotating pair is fixed on the frame, and the rotating pair is sleeved on the moving pair and connected with the sliding part of the moving pair. It is fixedly installed on one end of the fixed part of the moving pair, and the other end of the hook hinge is connected and fixed with the corresponding moving platform.

Further, each branch chain is arranged evenly around the circumference of the same axis.

Further, the Hooke hinge of each branch includes a first rotation axis and a second rotation axis, the first rotation axis and the second rotation axis intersect perpendicularly, the rotation axis of the rotation pair and the second rotation axis are parallel to each other, and the movement of the mobile pair The axis is perpendicular to the rotation axis of the rotating pair.

Further, the first rotation axis of the Hooke hinge of the first branch coincides with the first rotation axis of the Hooke hinge of the third branch, and the rotation axis of the rotating pair of the first branch and the rotating pair of the third branch are coincident. The rotation axes of the Hook hinges of the second branch are parallel to each other, the first rotation axis of the Hooke hinge of the second branch coincides with the first rotation axis of the Hooke hinge of the fourth branch, and the rotation axis of the rotating pair of the second branch is the same as that of the fourth branch. The rotation axes of the rotating pairs are parallel to each other, and the rotating axis of the platform rotating pair intersects vertically with the first rotating axis of the Hooke hinge of the first branch chain.

Compared with the prior art, the present invention has the following beneficial effects: the structure is simple, the design is reasonable, the operation is efficient, the motion output of the first moving platform and the second moving platform relative to the static platform 2R1T three degrees of freedom is realized, and it has a single motion branch type. , no ball joints, over-constrained, redundant drive and high modularity structural features, large working space, strong bearing capacity, high rigidity and high precision can not only be used as an independent motion module to achieve three freedoms of two rotations and one translation in space It can also use 2R1T three-degree-of-freedom parallel spindle head as the main body, which has broad application prospects in the fields of high-speed, precision and high-rigidity machining.

Description of drawings

The patent of the present invention is further described below in conjunction with the accompanying drawings.

FIG. 1 is a first structural schematic diagram of an embodiment of the present invention.

FIG. 2 is a second structural schematic diagram of an embodiment of the present invention (without a static platform).

FIG. 3 is a schematic structural diagram of a branched chain in an embodiment of the present invention.

FIG. 4 is a schematic structural diagram of the connection between the first moving platform and the second moving platform and the rotating pair in the embodiment of the present invention.

In the figure: 1- the first moving platform, 2- the second moving platform, 3- static platform, 4- the first branch, 5- the second branch, 6- the third branch, 7- the fourth branch; P-moving pair, R-rotating pair, U-Hook hinge; R5-platform turning pair;

SP1-the moving secondary axis of the first branch, SR1-the rotation axis of the first branch, SU11-the first rotation axis of the Hooke hinge of the first branch, SU12-the second rotation of the Hooke hinge of the first branch Axis, SP2 - the moving secondary axis of the second branch, SR2 - the rotation axis of the second branch, SU21 - the first rotation axis of the Hooke hinge of the second branch, SU22 - the second branch of the Hooke hinge Two rotation axes, SP3 - the moving secondary axis of the third branch, SR3 - the rotation axis of the third branch, SU31 - the first rotation axis of the Hooke hinge of the third branch, SU32 - the Hooke of the third branch The second rotation axis of the hinge, SP4-the moving secondary axis of the fourth branch, SR4-the rotation axis of the fourth branch, SU41-the first rotation axis of the Hooke hinge of the fourth branch, SU42-the fourth branch Hook hinge second rotation axis, SR5-platform rotation axis;

101-servo motor, 102-connecting rod, 103-guide rail, 104-lead screw pair, 105-slider, 106-moving frame.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

As shown in Figure 1-4, a three-degree-of-freedom parallel spindle head with over-constrained redundant drive includes a first moving platform, a second moving platform, a static platform, a first branch, a second branch, and a third Three branches and a fourth branch, the two ends of the first moving platform and the static platform are connected by the second branch and the fourth branch, and the two ends of the second moving platform and the static platform are connected by the first branch and the third branch, The first moving platform and the middle part of the second moving platform are connected by the platform rotation pair, and finally form a parallel mechanism with the ability of two rotations and one translation in space;

The structure of each branch is exactly the same, including the rotating pair, the moving pair and the Hooke hinge. The moving pair is the active moving pair of the mechanism. The sliding parts are connected, one end of the Hook hinge is fixedly installed on one end of the fixed part of the moving pair, and the other end of the Hook hinge is connected and fixed with the corresponding moving platform.

In this embodiment, the moving pair can use a linear motion mechanism driven by a linear motor, hydraulic pressure, pneumatic push rod, etc., or a lead screw slide table driven by a servo motor. Preferably, the moving pair adopts a lead screw slide table driven by a servo motor. combined organization.

The moving pair includes a slider 105, a screw pair 104, a linear guide 103 matched with the slider, a connecting rod 102, and a servo motor 101 that drives the screw pair. The slider is used as a guide for the moving pair, and the slider is installed On the moving frame 106, the linear guide rail is slidably matched, the moving frame is threaded with the screw pair, the moving frame is fixedly connected to the rotating pair, the linear guide rail is used as the moving part of the moving pair, and is fixedly connected to the connecting rod, the servo motor and Hooke The hinges are respectively installed on both ends of the connecting rod; the servo motor works, because the first rotating pair is connected with the static platform, the first sliding block cannot move relative to the static platform, and the first lead screw drives the first connecting rod. The rod moves relative to the first sliding block, so that the first branch chain moves relative to the static platform.

In this embodiment, the rotating pair can be hinged with a pin shaft and a bearing, and the platform rotating pair can be matched with a bearing and a shaft, but it is not limited to this.

In this embodiment, each branch chain is arranged evenly around the circumference of the same axis.

In this embodiment, the Hooke hinge of each branch chain includes a first rotation axis and a second rotation axis, the first rotation axis and the second rotation axis intersect perpendicularly, and the rotation axis of the rotation pair and the second rotation axis are parallel to each other. The moving axis of the pair is perpendicular to the rotation axis of the rotating pair.

In this embodiment, the first rotation axis of the Hooke hinge of the first branch is coincident with the first rotation axis of the Hooke hinge of the third branch, and the rotation axis of the rotating pair of the first branch is the same as that of the third branch. The rotation axes of the rotation pairs of the second chain are parallel to each other, the first rotation axis of the Hooke hinge of the second branch coincides with the first rotation axis of the Hooke hinge of the fourth chain, and the rotation axis of the rotation pair of the second chain coincides with the first rotation axis of the Hook hinge of the fourth chain. The rotation axes of the rotation pairs of the four branches are parallel to each other, and the rotation axes of the platform rotation pairs intersect perpendicularly with the first rotation axis of the Hooke hinge of the first branch chain.

In this embodiment, the design uses the static platform as the mechanism frame, the first moving platform and the second moving platform as the output components, and the moving pair of each branch chain as the active moving pair of the mechanism, so as to realize the first moving platform and the second moving platform. The moving platform relative to the static platform has two rotations and one translational motion output in the directions of rotation angle q, nutation angle w and height z.

In the embodiment of the present invention, the plane shape formed by the center of the Hooke hinge of each branch chain is not limited; the plane shape formed by the center of the rotating pair of each branch chain is not limited; The center of the Hook hinge is distributed on the first moving platform and the second moving platform in a square with the center of the platform rotating pair as the center, and the center of the rotating pair of each branch chain is distributed on the static platform in a square. 110 mm <d1< 290mm, 110 mm <d2<290mm, 110 mm <d3< 290mm, 110 mm <d4< 290mm, a= 300mm, b=195mm, where a represents the center of the rotation pair of each branch chain The diameter of the circumcircle of the square formed; b represents the distance from the center of the Hooke hinge of the second branch to the center of the Hooke hinge of the fourth branch; d1 represents the center of the rotation pair of the first branch to the first branch The distance from the center of the Hooke hinge of the chain; d2 represents the distance from the center of the rotating pair of the second branch to the center of the Hooke hinge of the second branch; d3 represents the center of the rotating pair of the third branch to the third branch The distance from the center of the Hooke hinge of the chain; d4 represents the distance from the center of the rotation pair of the fourth branch to the center of the Hooke hinge of the fourth branch.

The height z represents the distance between the center of the circumscribed circle formed by the center of the rotating pair of each branch chain to the center of the Hooke hinge of the second branch and the center point of the connecting line of the center of the Hooke hinge of the fourth branch. distance.

For example: take q=0°, w=0°, z=110mm as the initial pose of the mechanism, at this time d1, d2, d3, d4 are 121.9mm, 121.9mm, 121.9mm, 121.9mm respectively.

(1) If the attitude q=10°, w=15°, z=130mm as the target attitude, according to the inverse kinematics of the mechanism, d'1, d'2, d'3, d'4 can be obtained as 124.8 respectively mm, 165.0mm, 157.1mm, 118.7mm, from this, the moving amount Δ of the moving pair of the first branch, the moving pair of the second branch, the moving pair of the third branch and the moving pair of the fourth branch can be obtained. d1=2.9mm, ∆d2=43.1mm, ∆d3=35.2mm, ∆d4=-3.2mm.

(2) If the attitude q=-15°, w=-30°, z=160mm is used as the target attitude, according to the inverse kinematics of the mechanism, d'1, d'2, d'3, d'4 can be obtained respectively. are 197.2mm, 129.1mm, 143.0mm, and 218.8mm, from which the movement of the moving pair of the first branch, the moving pair of the second branch, the moving pair of the third branch and the moving pair of the fourth branch can be obtained. Quantities Δd1=75.3mm, Δd2=7.2mm, Δd3=21.1mm, Δd4=96.9mm.

(3) If the attitude q=10°, w=-25°, z=200mm as the target attitude, according to the inverse kinematics of the mechanism, d'1, d'2, d'3, d'4 can be obtained as 189.3mm, 170.3mm, 225.3mm, 249.0mm, from this, the moving amount of the moving pair of the first branch, the moving pair of the second branch, the moving pair of the third branch and the moving pair of the fourth branch can be obtained. ∆d1=67.4mm, ∆d2=48.4mm, ∆d3=103.4mm, ∆d4=127.1mm.

If this patent discloses or involves parts or structural parts that are fixedly connected to each other, then, unless otherwise stated, fixed connection can be understood as: detachable fixed connection (for example, using bolts or screws), can also be understood as: Non-removable fixed connections (such as riveting, welding), of course, mutual fixed connections can also be replaced by a one-piece structure (for example, integrally formed using a casting process) (except that it is obviously impossible to use a one-piece forming process).

In the description of this patent, it should be understood that the terms "portrait", "horizontal", "upper", "lower", "front", "rear", "left", "right", "vertical", The orientation or positional relationship indicated by "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this patent, rather than indicating or It is implied that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of this patent.

The above preferred embodiments further describe the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principle of the present invention, any modifications, equivalent replacements, improvements, etc. made should be included within the protection scope of the present invention.

Claims (4)

1. The utility model provides a three degree of freedom parallel spindle heads that contain redundant drive of overconstraint which characterized in that: the device comprises a first movable platform, a second movable platform, a static platform, a first branched chain, a second branched chain and a third branched chain, wherein two ends of the first movable platform are connected with the static platform through the second branched chain and the fourth branched chain;

the structure of each branched chain is completely the same, and all include revolute pair, sliding pair and hooke's hinge, revolute pair fixed mounting is in the frame, and the revolute pair cover is established on the sliding pair and is connected with the sliding part of sliding pair, and hooke's hinge one end fixed mounting is in the fixed part one end of sliding pair, and the other end of hooke's hinge is connected fixedly with the movable platform that corresponds.

2. The three-degree-of-freedom parallel spindle head with the overconstrained redundant drive of claim 1, wherein: all the branched chains are circumferentially and uniformly distributed relative to the same axis.

3. The three-degree-of-freedom parallel spindle head with the overconstrained redundant drive of claim 1, wherein: the Hooke joint of each branched chain comprises a first rotating axis and a second rotating axis, the first rotating axis is perpendicularly intersected with the second rotating axis, the rotating axis of the revolute pair is parallel to the second rotating axis, and the moving axis of the revolute pair is perpendicular to the rotating axis of the revolute pair.

4. The three-degree-of-freedom parallel spindle head with the overconstrained redundant drive of claim 3, wherein: the first rotating axis of the Hooke joint of the first branched chain is superposed with the first rotating axis of the Hooke joint of the third branched chain, the rotating axis of the revolute pair of the first branched chain is parallel to the rotating axis of the revolute pair of the third branched chain, the first rotating axis of the Hooke joint of the second branched chain is superposed with the first rotating axis of the Hooke joint of the fourth branched chain, the rotating axis of the revolute pair of the second branched chain is parallel to the rotating axis of the revolute pair of the fourth branched chain, and the rotating axis of the platform revolute pair is vertically crossed with the first rotating axis of the Hooke joint of the first branched chain.

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