CN111844075B

CN111844075B - Coordinate measuring self-driven joint arm

Info

Publication number: CN111844075B
Application number: CN202010732693.9A
Authority: CN
Inventors: 杨洪涛; 沈梅; 胡毅; 范禄源; 胡婷婷
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2022-02-11
Anticipated expiration: 2040-07-27
Also published as: CN111844075A

Abstract

The invention discloses a coordinate measurement self-driven joint arm which comprises a base, wherein a shoulder swing base is arranged on the base, a shoulder swing arm in rotary connection is arranged on one side of the shoulder swing base, a large arm is arranged on the shoulder swing arm, an elbow swing base is arranged at the top end of the large arm, an elbow swing arm is arranged on the elbow swing base, a small arm is arranged on the elbow swing arm, a wrist swing base is arranged at the top end of the small arm, a wrist swing head is arranged on the wrist swing base, a hand swing base is arranged on the wrist swing head, a hand swing head in rotary connection is arranged on the hand swing base, a measuring head fixing barrel is arranged on the hand swing head, a measurer is arranged on the measuring head fixing barrel, and a probe is arranged at the top end of the measurer. The invention ensures the compact structure of the wrist, eliminates the error caused by the flexible deformation of the connecting rod, and utilizes the circular grating measuring system to realize the high-precision positioning measurement of the workpiece by the articulated arm measuring machine so as to complete the on-line automatic measurement of the workpiece parameters.

Description

Coordinate measuring self-driven joint arm

Technical Field

The invention relates to the field of industrial robots, in particular to a coordinate measurement self-driven articulated arm.

Background

The design of the existing industrial robot manipulator is mainly based on binocular vision or machine vision technology, the design target of the existing industrial robot manipulator is mainly biased to technical application, for example, the robot manipulator is controlled by a computer to carry out positioning and grabbing, workpiece carrying and sorting and packaging, the design target of the self-driven articulated arm coordinate measuring machine is to carry out workpiece parameter measurement, high-precision automatic measurement in online processing is realized through a self-driven control system, the robot manipulator is not applied to robot technology, and the technical requirement of the self-driven articulated arm coordinate measuring machine is higher than that of the industrial robot manipulator. The design of the industrial mechanical arm only requires repeated positioning precision so as to complete accurate positioning of a product and moving and conveying of a target point, and has the characteristics of high load and low precision, so the positioning precision level is lower, the self-driven articulated arm coordinate measuring machine belongs to low-load high-precision measuring equipment, the design requirements not only comprise the repeated positioning precision of a workpiece measuring point, but also provide the technical requirement of absolute measuring precision for the measuring work of the measuring machine, the repeated positioning precision and the absolute measuring precision are within 0.05mm, both the design precisions are higher than the design precision of the industrial mechanical arm, the design of the self-driven articulated arm coordinate measuring machine is an innovative structure which is improved and designed based on the structural design of the traditional articulated arm coordinate measuring machine, the measurement driving mode is greatly different from that of the traditional articulated arm coordinate measuring machine, and the traditional manual articulated arm coordinate measuring machine mainly depends on manual operation of a worker to carry out off-line measurement in the measuring process, but the measurement pose is random, so that the stability of the measurement result is poor;

because the tasks of the industrial robot and the mechanical arm are mainly to complete the actions of carrying, grabbing and the like, the load is heavy, and the industrial robot and the mechanical arm are concentrated on an end effector, when the industrial robot and the mechanical arm execute the tasks, the starting point and the target point are clearly known, the trajectory planning mainly comprises point-to-point motion, and generally, polynomial curves, spline curves and other curves are adopted to interpolate the trajectory, so that the motion trajectory research between the two points is realized. In the existing trajectory research of the mechanical arm, many point-to-point trajectory planning is adopted. Then, selecting a track function from a series of functions such as a polynomial function, a B spline function and the like according to the situation, and constraining the track function in the aspects of position, speed, acceleration and the like, wherein when constraining the termination point, the constraint of zero speed is usually selected; the self-driven articulated arm coordinate measuring machine mainly aims at carrying out high-precision positioning and measuring work, and needs to move according to a fixed track until the measurement is finished after reaching a specified point, aiming at the situation, a self-driven articulated arm for coordinate measurement is provided, according to the self-gravity of the load borne by the self-driven articulated arm, when the self-driven articulated arm for coordinate measurement carries out positioning measurement, the approximate space position is estimated according to a measured model, the speed of the measuring machine is not zero when the self-driven articulated arm is close to the measurement point, when a measuring head touches a surface to be measured, the measuring head is triggered to stop moving, the accurate position positioning and the workpiece measurement are finished, in the measuring process of the self-driven articulated arm, when the self-driven articulated arm runs to the vicinity of the surface of an object to be measured, because a small distance is arranged away from the measurement point, the self-driven articulated arm does not stop at the position of the termination point, the speed movement can be continuously kept until the constant-force triggering measuring head touches the surface of the object to be measured, this is done.

Disclosure of Invention

The invention aims to provide a coordinate measurement self-driven articulated arm which is designed into a 6-degree-of-freedom structure, a servo control system and a circular grating measuring system are added into 6 rotating joints of a self-driven articulated arm coordinate measuring machine according to the requirement of low-load high-precision measuring equipment of the self-driven articulated arm coordinate measuring machine and in combination with the high-precision design requirement of the repeated positioning precision and the absolute measuring precision of the self-driven articulated arm coordinate measuring machine, the structure design simultaneously considers the error influence of the repeated positioning error and the absolute measuring error of the added servo control system and the circular grating measuring system on the articulated arm coordinate measuring machine, the self-driven articulated arm coordinate measuring machine is structurally optimized, the self-driven articulated arm coordinate measuring machine is subjected to the motion process of three stages of acceleration, uniform speed and deceleration when the measuring machine measures a workpiece through autonomous path planning, the measurement stability of measurement is guaranteed, the servo control system is used for enabling the articulated arm coordinate measuring machine to achieve on-line automatic measurement, the circular grating measuring system is used for enabling the articulated arm coordinate measuring machine to achieve high-precision positioning measurement of workpieces, and on-line automatic measurement of workpiece parameters is completed.

The purpose of the invention can be realized by the following technical scheme:

the utility model provides a coordinate measurement self-driven articulated arm, which comprises a base, the base is equipped with shoulder swing base on the base, shoulder swing base one side is equipped with the shoulder swing arm of rotation connection, be equipped with big arm in the shoulder swing arm, big arm top is equipped with elbow swing base, be equipped with the elbow swing arm on the elbow swing base, be equipped with the forearm in the elbow swing arm, the forearm top is equipped with wrist swing base, be equipped with the wrist yaw on the wrist swing base, be equipped with the hand swing base on the wrist swing base of rotation connection, be equipped with the fixed section of thick bamboo of gauge head on the hand swing, be equipped with the caliber on the fixed section of thick bamboo of gauge head, the caliber top is equipped with the probe.

Further, be equipped with first integration joint module in the base, shoulder swing base rotates through first integration joint module and base to be connected, is equipped with second integration joint module between shoulder swing base and the shoulder swing arm, is equipped with third integration joint module between elbow swing base and the elbow swing arm, is equipped with fourth integration joint module between elbow swing arm and the wrist swing base, is equipped with fifth integration joint module between wrist swing base and the wrist yaw, is equipped with sixth integration joint module between hand swing base and the hand yaw.

Further, the total arm length of the coordinate measurement self-driven articulated arm is designed to be 1m, 0.4m is distributed from the shoulder to the large arm of the elbow, 0.25m is distributed from the elbow to the small arm of the wrist, the length of the wrist is 0.2m, and 0.15m is distributed to the measuring head;

the large arm and the small arm are made of aluminum alloy, wherein the outer diameter of the large arm is 72mm, the wall thickness is 5mm, and the arm length is 120 mm;

the outer diameter of the small arm is 72mm, the wall thickness is 5mm, and the arm length is 110 mm.

Further, the coordinate measurement self-driven articulated arm adopts ANSYS and Adams analysis software to perform simulation analysis on parts of the measuring machine and the whole measuring machine, the designed parts and the model selection equipment are optimized and perfected according to simulation result feedback, and the movement process of the measuring machine in three stages of acceleration, constant speed and deceleration is realized through autonomous path planning when the measuring machine measures the workpiece.

The invention has the beneficial effects that:

1. the measuring process of the coordinate measuring self-driven joint arm is different from the traditional joint arm measuring machine, an industrial mechanical arm and a robot, when the joint arm measures a workpiece, the joint arm sets different speeds and accelerations for each joint to perform dynamic simulation through the motion process of three stages of acceleration, uniform speed and deceleration, a path planning model of the self-driven joint arm coordinate measuring machine is established, the stability of touch measurement during on-line measurement of the measuring machine is improved, and the positioning precision and the measuring precision of the measuring machine are guaranteed;

2. according to the invention, a motor control system is added in each joint, the high-precision requirements of a self-driven articulated arm coordinate measuring machine on repeated positioning and absolute measurement are combined, according to the structural characteristics of the measuring machine, the measurement errors and the positioning errors caused by each error source in the dynamic measurement working process of the measuring machine are fully considered in the aspect of the control system, a simulation experiment is utilized to carry out path planning modeling on the self-driven articulated arm coordinate measuring machine, and the circuit of the measuring machine control system is innovatively designed based on a path planning model;

3. the invention ensures the compact structure of the wrist part and eliminates the error caused by the flexible deformation of the connecting rod;

4. according to the automatic measurement characteristics of the coordinate measurement of the self-driven articulated arm, a drive component design is added into each joint of the measuring machine, wherein the drive component design comprises a motor, a reducer, an encoder and the like, the simulation analysis is carried out on the parts of the measuring machine and the whole measuring machine by adopting analysis software such as ANSYS, Adams and the like, and the designed parts and the model selection equipment are optimized and perfected according to the feedback of the simulation result.

Drawings

The invention will be further described with reference to the accompanying drawings.

FIG. 1 is a schematic view of the construction of a coordinate measuring self-driven articulated arm according to the invention;

FIG. 2 is a schematic view of the construction of the coordinate measuring self-driven articulated arm of the present invention;

FIG. 3 is a schematic view of the arm portion of the coordinate measuring self-actuated joint of the present invention;

FIG. 4 is a schematic view of the construction of the shoulder swing base of the present invention;

FIG. 5 is a schematic view of a shoulder swing arm configuration of the present invention;

FIG. 6 is a schematic view of an elbow swing arm configuration of the present invention;

FIG. 7 is a schematic view of an elbow swing arm configuration of the present invention;

FIG. 8 is a schematic structural view of a first integrated joint module according to the present invention;

FIG. 9 is a schematic illustration of the elbow swing base of the present invention;

figure 10 is a schematic view of the elbow swing base of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "opening," "upper," "lower," "thickness," "top," "middle," "length," "inner," "peripheral," and the like are used in an orientation or positional relationship that is merely for convenience in describing and simplifying the description, and do not indicate or imply that the referenced component or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered as limiting the present invention.

The utility model provides a coordinate measurement self-driven articulated arm, which comprises a base 1, as shown in figure 1, figure 2, as shown in figure 3, base 1, be equipped with shoulder swing base 2 on the base 1, 2 one side of shoulder swing base is equipped with the shoulder swing arm 3 of rotation connection, be equipped with big arm 4 on the

shoulder swing arm

3, 4 tops of big arm are equipped with elbow swing base 5, be equipped with elbow swing arm 6 on the elbow swing base 5, be equipped with forearm 7 on the elbow swing arm 6, 7 tops of forearm are equipped with wrist swing base 8, be equipped with wrist yaw 9 on the wrist swing base 8, be equipped with hand swing base 10 on the wrist yaw 9, be equipped with the hand yaw 11 of rotation connection on the hand swing base 10, be equipped with the fixed section of thick bamboo 12 of gauge head on the hand yaw 11, be equipped with caliber 13 on the fixed section of gauge head 12, caliber 13 tops of gauge head are equipped with probe 14.

Be equipped with first integration joint module 15 in the base 1, as shown in fig. 1, fig. 2, fig. 3, shoulder swing base 2 rotates with base 1 through first integration joint module 15 to be connected, be equipped with second integration joint module 16 between shoulder swing base 2 and the shoulder swing arm 3, be equipped with third integration joint module 17 between elbow swing base 5 and the elbow swing arm 6, be equipped with fourth integration joint module 18 between elbow swing arm 6 and wrist swing base 8, be equipped with fifth integration joint module 19 between wrist swing base 8 and wrist balance 9, be equipped with sixth integration joint module 20 between hand swing base 10 and hand balance 11.

The joint structure layout (rotation-pitching-rotation-pitching) is different from that of the traditional articulated arm coordinate measuring machine, wherein the shoulder joint part is designed to have 2 degrees of freedom (a rotation joint and a pitching joint); because the elbow stress is concentrated and the moment of inertia is large, in order to reduce the flexible deformation of the joint, the elbow joint part is designed into 1 degree of freedom (pitching joint); considering that when the articulated arm measures a complex curved surface, the wrist is required to have higher flexibility, the wrist is positioned at the foremost end of the measuring machine and has smaller stress, and the wrist joint part is designed to have 3 degrees of freedom (a pitching joint, a rotating joint and a rotating joint);

the

joints

4, 5 and 6 are directly butted end to end, so that the wrist structure is compact, and errors caused by flexible deformation of the connecting rod are eliminated.

In order to avoid the pivot to take place great torsional deformation, servo drive device adopts the integrated joint module to replace the axle system structure before, and the flexible executor QDD series that INNFOS independently researched and developed is selected to the integrated joint module, and this integrated joint module mainly includes: servo motor, harmonic speed reducer ware, pivot, cross bearing.

According to the joint distribution condition of the newly designed joint arm, the shoulder part is provided with a pair of rotary joints and pitching joints, the elbow part is provided with a pitching joint, the wrist part is provided with a pitching joint and two rotary joints, in order to balance the contradiction between the overall structural strength and the rotational inertia of the joint arm, the main body is made of high-strength aluminum alloy, the joints and the base part are made of alloy steel,

the total arm length of the articulated arm is designed to be 1m, 0.4m is allocated to the large arm from the shoulder to the elbow, 0.25m is allocated to the small arm from the elbow to the wrist, the length of the wrist is 0.2m, and 0.15m is allocated to the measuring head. The large arm and the small arm are made of aluminum alloy, wherein the outer diameter of the large arm is 72mm, the wall thickness is 5mm, and the arm length is 120 mm; the outer diameter of the small arm is 72mm, the wall thickness is 5mm, and the arm length is 110 mm.

The measuring head part mainly comprises a measuring head base and a measuring head. The design adopts a trigger type measuring head, wherein the measuring head adopts a TP200 measuring head in Renysha, the measuring head designed by the design is mainly used for measuring, the bearing is small, and the quality of the measuring head part has great influence on a subsequent joint, so that the measuring head connecting rod is designed into a hollow thin-wall structure, and the torsional deformation and the joint torque of the subsequent joint can be reduced.

According to the automatic measurement characteristics of the self-driven articulated arm coordinate measurement, a driving part design is added in each joint of the measuring machine, and comprises a motor, a reducer, an encoder and the like, therefore, in the aspect of structural design, the base, the joint base connecting piece, the joint swing arm connecting piece, the measuring rod and other parts of the self-driven articulated arm coordinate measuring machine need to be designed by combining the type and the structural size of the added control driving part, in the structural design process, the influence of measurement errors and positioning errors caused by various error sources when the measuring machine works in dynamic measurement needs to be considered, the influence comprises dynamic errors caused by the installation position of a motor and dynamic deformation under the action of driving force and inertia force, analysis software such as ANSYS, Adams and the like is adopted to carry out simulation analysis on parts of the measuring machine and the whole measuring machine, and the designed parts and the selected equipment are optimized and perfected according to the feedback of a simulation result.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed.

Claims

1. A coordinate measurement self-driven joint arm comprises a base (1) and is characterized in that the base (1) is provided with a shoulder swing base (2) on the base (1), one side of the shoulder swing base (2) is provided with a shoulder swing arm (3) connected in a rotating manner, a large arm (4) is arranged on the shoulder swing arm (3), the top end of the large arm (4) is provided with an elbow swing base (5), the elbow swing base (5) is provided with an elbow swing arm (6), the elbow swing arm (6) is provided with a small arm (7), the top end of the small arm (7) is provided with a wrist swing base (8), the wrist swing base (8) is provided with a wrist swing head (9), the wrist swing head (9) is provided with a hand swing base (10), the hand swing base (10) is provided with a hand swing head (11) connected in a rotating manner, the hand swing head (11) is provided with a measuring head fixing barrel (12), the measuring device (13) is arranged on the measuring head fixing barrel (12), the top end of the measurer (13) is provided with a probe (14);

a first integrated joint module (15) is arranged in the base (1), the shoulder swing base (2) is rotatably connected with the base (1) through the first integrated joint module (15), a second integrated joint module (16) is arranged between the shoulder swing base (2) and the shoulder swing arm (3), a third integrated joint module (17) is arranged between the elbow swing base (5) and the elbow swing arm (6), a fourth integrated joint module (18) is arranged between the elbow swing arm (6) and the wrist swing base (8), a fifth integrated joint module (19) is arranged between the wrist swing base (8) and the wrist swing head (9), and a sixth integrated joint module (20) is arranged between the hand swing base (10) and the hand swing head (11);

the joint structure of the articulated arm is arranged as follows: rotation + pitch + rotation + pitch, wherein the shoulder joint part is designed to have 2 degrees of freedom, namely a rotation joint + pitch joint; the elbow joint part is designed to have 1 degree of freedom, namely a pitching joint; the wrist joint part is designed to have 3 degrees of freedom, namely a pitching joint, a rotating joint and a pitching joint;

the joint arm main body is made of high-strength aluminum alloy, and the joint and the base part are made of alloy steel;

the large arm and the small arm are made of aluminum alloy;

first integration joint module (15), second integration joint module (16), third integration joint module (17), fourth integration joint module (18), fifth integration joint module (19) and sixth integration joint module (20) all are the flexible executor QDD series integration joint module who selects INNFOS independently to research and develop, and this integration joint module mainly includes: the device comprises a servo motor, a harmonic reducer, a rotating shaft and a cross bearing;

the coordinate measurement self-driven articulated arm adopts ANSYS and Adams analysis software to carry out simulation analysis on parts of the measuring machine and the whole measuring machine, optimizes and perfects designed parts and selected equipment according to simulation result feedback, and realizes the motion process of three stages of acceleration, constant speed and deceleration when the measuring machine measures a workpiece through autonomous path planning.

2. A coordinate measurement self-driven articulated arm according to claim 1, wherein the total arm length of the arm is designed to be 1m, 0.4m is assigned to the large arm from shoulder to elbow, 0.25m is assigned to the small arm from elbow to wrist, 0.2m is assigned to wrist length, 0.15m is assigned to the stylus;

wherein the outer diameter of the large arm is 72mm, the wall thickness is 5mm, and the arm length is 120 mm;