TW201509615A - Robot arm rotation axis measurement system and measurement method applying the same - Google Patents

Abstract

This invention relates to a robot arm rotation axis measurement system and a measurement method applying the same, more particularly to a measurement system for measuring the rotation axis error and backlash of a robot arm. Before the measurement system performs rotation axis positioning error measurement, an angle sensor and a positioning indexer are mounted at the tail end of the robot arm under test, and measurement parameters, measurement range, measurement gap and the backlash are set in conjunction with the built-in program of a computer. After the rotation axis of each joint of the robot arm is rotated to a fixed angle, the angle sensor is rotated along with the positioning indexer by the same angle reversely. Accordingly, deviation value is caught according to gravity balance. In addition, after the measurement stroke, the measurement system analyzes all error results to determine angle positioning error of each rotation axis under test of the robot arm. The analysis results can establish a compensation parameter table for the robot arm to perform calibration. Furthermore, this system can be installed easily without needing complicated optical lens set, thereby greatly reducing the installation time.

Description

Mechanical arm rotating shaft measuring system and its application measuring method

The invention relates to the technical field of measuring the rotating shaft of a mechanical arm, in particular to a measuring system and a method for measuring the rotating shaft of a mechanical arm which can complete more than one rotating shaft error, so as to achieve convenient erection and multiple joints can be completed The rotation axis is measured to effectively improve the calibration efficiency.

According to the requirement that the mechanical arm is used for industrial automation production, the positioning accuracy is higher and higher. The movement positioning of the six-axis vertical joint type mechanical arm is performed by six joint rotation axes, and the problem of the rotation axis errors of the joints becomes variable. It is very important that the general six-axis vertical joint type robot arm has the following types of error: if the rotation error of the joint rotation axis is generated by the length of the robot arm, the position error of the enlarged end point is generated; and the drive unit of the joint rotation axis The backlash error also causes the error of the rotation angle of the joint rotation axis; in addition, the installation of the eccentricity problem will produce a periodic angle error; in addition, the long-term wear will also affect the rotation accuracy of the joint rotation axis of the robot arm.

Therefore, it is necessary to periodically check the error of the rotation axis of each joint of the robot arm, and the error measurement of the rotation axis of the joint of the robot arm is mainly based on the positioning error, but the error of the rotation axis of each joint cannot be separated, and the joint rotation should be measured independently. The rotation error of the rotating shaft requires the use of a laser interferometer, but it is difficult to set up and it needs to be re-erected once every joint axis is measured. The measurement is extremely time consuming and inconvenient.

Furthermore, the high-precision angle sensors commonly used in the market mostly use laser light as a measurement medium, such as an automatic collimator, a laser interferometer, etc., although such systems are non-contact measurement systems, have sensitivity and stability. The advantage of high sex. However, it has the following shortcomings: First, the measurement accuracy is susceptible to temperature, air pressure and humidity. Before the measurement, it is necessary to warm up the machine. When measuring, the light path cannot be blocked, and the use has the limitation of angle and space. Furthermore, when measuring the joint rotation axis error, the optical path mirror must be re-calibrated, and the measurement procedure is quite cumbersome. Eccentric alignment is not easy with laser alignment.

In other words, the error measurement of the joint rotation axis of the existing robot arm has the problems of inconvenient erection, measurement efficiency, and inability to quickly measure the multi-axis rotation axis, which not only increases the measurement time and cost, but also cannot effectively improve the measurement accuracy, so how Solving this problem is an important issue in the industry in measuring the error of the rotation axes of the joints of the robot arm.

The reason is that the inventor of the present invention has in-depth discussion on the error measurement requirements of the joint rotation axis of the aforementioned mechanical arm, and actively seeks solutions through years of experience in related industries and research and development, and has been successfully developed through continuous efforts and trials. A mechanical arm rotating shaft measuring system and a measuring method thereof are applied.

The object of the present invention is to provide a mechanical arm rotation axis The measuring system can simplify the assembly, is easy to set up, and does not require a complicated optical lens set, thereby greatly reducing the erection time and effectively improving the measurement accuracy.

A second object of the present invention is to provide a mechanical arm rotating shaft measuring system and a measuring method thereof, which can complete the error measurement of more than one rotating shaft and improve the measuring efficiency.

The robot arm rotating shaft measuring system capable of achieving the above object includes: a positioning indexer and an angle sensor, and the angle sensor and the positioning indexer are connected to a computer capable of capturing and calculating, in the computer And the built-in software for analyzing error; wherein: the positioning indexer is disposed on a tail end of one of the mechanical arm rotation axes, and the positioning indexer has an adapter plate coupled with the joint rotation axis of the mechanical arm tail end, The system is configured to simultaneously rotate the equal angles of the plurality of ranging points in the reverse direction; the angle sensor is fixed on the positioning indexer, and has a standard zero point, according to the plurality of angle data output by the angle sensor The angle error is analyzed successively with the standard zero point, and then multiple angular offset values of the plurality of ranging points are successively obtained, and used as the positioning error measurement of the joint rotation axis.

Thereby, through the specific implementation of the foregoing technical means of the present invention, the invention can complete the measurement of the plurality of joint rotation axes of the entire six-axis robot arm, and analyze the use of the computer, thereby knowing the angular positioning error and performing the error value. After the analysis, the compensation report is output, so that the joint rotation axis can get the correct compensation before processing, and the six-axis robot arm can be measured twice after being set up. The joint rotation axis, and compared with the conventional optical measurement system, the lightning detector and the mirror have a dead angle, and the measurement system of the invention has no such problem, and the measurement angle range is large.

1‧‧‧ Positioning indexer

11‧‧‧Adapter plate

2‧‧‧ Angle Sensor

21‧‧‧ housing

22‧‧‧ pedestal

23‧‧‧attenuation

24‧‧‧Separation slot

25‧‧‧Adjustment Department

26‧‧‧Adjusting bolts

5‧‧‧ Six-axis robot

55‧‧‧ Joint rotation axis

6‧‧‧ computer

1 is a schematic diagram of a simple structure of a rotating shaft measuring system for a mechanical arm of the present invention; FIG. 2 is a schematic view showing the arrangement of a positioning indexer and an angle sensor in a rotating shaft measuring system of the mechanical arm of the present invention; FIG. 3 is a rotating shaft of the mechanical arm of the present invention; A schematic diagram of a schematic structure of an angle sensor in a measurement system; FIG. 4 is a schematic diagram of a bottom surface of an angle sensor in a robotic arm rotation axis measuring system of the present invention.

Figures 6-1 to 10-3 are schematic views of the actual measurement of the mechanical arm applied to the rotation axes of different joints according to the present invention.

Referring to FIG. 1 , the mechanical arm rotating shaft measuring system of the present invention is used for measuring the error of each joint rotating shaft 55 of the six-axis robot arm 5 , and the measuring system includes a positioning indexer 1 and a sense of angle. The detector 2 is composed, and the angle sensor 2 and the positioning indexer 1 are connected to a computer 6 which can be retrieved and operated (as shown in FIG. 2), and the software 6 has built-in software for analyzing errors; The positioning indexer 1 is disposed on the joint rotation shaft 55, and the positioning indexer 1 has an adapter plate 11 coupled to the joint rotation shaft 55 of the robot arm tail end, which is connected to the parameter while rotating in reverse The equal angles of the ranging points are used to output a plurality of angle data of the plurality of ranging points, and the high-precision positioning indexer 1 has a minimum rotation degree of 5 degrees, and the 360 degree rotation thereof can be positioned, and the positioning accuracy of the indexing device 1 is positioned. ±5μm/m (±1 second), which has a relatively small amount of change, and uses RS-232 wired transmission interface as a standard for rotation, which can be used for verification of rotational axis positioning error measurement; As shown in FIG. 1 and FIG. 2, the detector 2 is fixed on the positioning indexer 1 and has a standard zero point. According to the angle data output by the angle sensor 2, the standard and the standard are successively and standard. The zero point analyzes the angle error to successively obtain a plurality of angular offset values of the plurality of ranging points. The angle sensor 2 is fixed to the rotating end of the positioning and indexing device 1 by a casing 21, and the positioning indexer 1 and the sense of angle The detector 2 can be connected to the computer 6, The angular offset values for the angle sensor 2 are measured and transmitted to the computer 6 to determine the angular deviation values of the plurality of ranging points of the joint rotation axes 55. Furthermore, as shown in FIG. 3, the housing 21 of the angle sensor 2 has a base 22 for selectively locking the positioning indexer 1, and a taper portion 23 is formed on the base 22. The partitioning groove 24 is configured to form the adjusting portion 25 of the base 22 which can be finely adjusted at one end by using the dividing groove 24, and the base 22 is provided with at least one adjusting bolt 26 (shown in FIG. 4) for connecting the base 22 for The adjusting bolt 25 is used to finely adjust the position of the adjusting portion 25, and the base 22 is covered with a casing 21 to protect the base 22 Upper angle sensor 2; moreover, the angle sensor 2 can be measured to a horizontal angle of 0 ± .00035 degrees (± 1.26 seconds), which has a relatively small amount of change, and uses RS-485 wired transmission Interface, with the multi-point transmission function of the same protocol, the angle sensor 2 as the joint rotation axis 55 positioning error measurement equipment; another computer 6 built-in soft system using Microsoft Visual C#, in line with the .NET Framework specification, can be The related platform runs, and the built-in software is integrated into a set of analysis system for precise measurement of the rotating axis of the robot arm by using hardware devices; thereby, the group constitutes a simple and measurable multi-axis mechanical arm rotating shaft measuring system By.

As for the measuring method of the measuring system of the present invention, please refer to FIG. 1 and FIG. 5, wherein the measuring process includes a step of installing the positioning indexer, an angle detecting step of the angle sensor 2, and a setting joint. The measuring point step of the rotating shaft 55, the measuring point step of setting the positioning indexer 1, the forward rotation step of the joint rotation axis 55, the angle determining step of the angle sensor 2, and the reverse sequential rotation step of the positioning indexer 1 The angle sensor 2 obtains an angle offset value step, a stroke determination step, and an analysis error value step to obtain compensation values of the joint rotation axes 55; wherein: step 1, the positioning and positioning indexer 1 step, The positioning indexer 1 is directly mounted on the end of the joint rotation shaft 55 to be measured by the robot arm, and the positioning indexer 1 is coupled to the joint rotation shaft 55 of the robot arm through the adapter plate 11, and the angle sensor is 2 is installed on the positioning indexer 1; Step 2, the angle sensor 2 origin returning to the zero step, after completing the positioning of the positioning indexer 1, manually using the angle sensor 2 as a standard zero point [or a reference horizontal plane] as a positioning indexer 1 correction reference; Step 3: The step of setting the distance measuring point of the joint rotation axis 55, after completing the angle adjustment, manually setting the stroke parameters of the plurality of angles of the plurality of ranging points of the joint rotation axis to the computer 6; Step 4 The step of setting the distance measuring point of the positioning indexer 1 is completed, and after setting the stroke parameters of the plurality of angles of the joint rotating shaft 55, the reverse rotation angle of the plurality of measuring points of the positioning indexing device 1 is manually set for the computer 6 to prepare. Start recording the offset value of each rotation angle of the plurality of ranging points; in step 5, the joint rotation axis 55 is in the forward rotation step, as shown in FIG. 6-1 to FIG. 6-3 [other joint rotation axes 55 are diagrams 7-1 to 7-3, 8-1 to 8-3, 9-1 to 9-3, and 10-1 to 10-3, the procedure for completing the aforementioned manual installation is completed. After that, the output parameters are automatically executed by the computer 6 to the joint rotation axes 55, so that the robot arm The rotation axis 55 performs a plurality of distance measurement points for a forward rotation angle according to the set stroke; and in step 6, the angle sensor 2 range determination step determines whether the angle sensor 2 exceeds the measurement range for the computer 6, if not If the measurement range is exceeded, the process of step 6 is re-executed. Otherwise, if the measurement range has been exceeded, step 7 is performed; in step 7, the positioning indexer 1 reverses the sequential rotation step, and after the computer 6 determines that the angle sensor 2 exceeds the measurement range, the positioning indexer is made. 1 according to the angle of the reverse rotation angle of the plurality of distance measuring points, thereby outputting a plurality of angle data of the plurality of distance measuring points; in step 8, the angle sensor 2 obtains the angle offset value step, and completing the positioning indexer 1 After the reverse rotation angle, according to the plurality of angle data output by the angle sensor 2, the angle error is analyzed successively with the standard zero point, and multiple angle offset values of the plurality of distance measurement points are successively obtained, thereby indicating the The angular difference relationship between the joint rotation axis 55 and the positioning indexer 1 is continued; then, returning to step 5, the joint rotation axis 55 performs the forward rotation angle of the next distance measurement point; for example, the entire rotation point of the joint rotation axis 55 is rotated. Then, step 9 is performed; step 9, the stroke judging step, after the angle sensor 2 obtains the angle offset value step, whether to complete the stroke is completed, and if the measurement stroke has not been completed, return to the joint rotation axis 55 for the positive sequence Rotate the steps and perform the aforementioned measurement process in sequence. If the measurement stroke has been completed, proceed to step 10; step 10, the analysis error value step, after completing the entire measurement stroke, sequentially obtain a plurality of angular offset value outputs of the plurality of ranging points, when the mechanical arm joint The rotating shaft 55 rotates clockwise [forward] by a fixed angle, and the angle sensor 2 mounted on the positioning indexer 1 reverses a fixed angle and captures a horizontal error value; wherein steps 1 to 4 are Manually install the program, and steps 5~9 are used to automatically execute the measurement program for the computer 6 output parameter program. Finally, the computer 6 is used to analyze the error value and then manually output the compensation report, and Steps 5 to 9 are performed cyclically one by one when correspondingly measuring the joint rotation axes 55, so that the measurement system of the present invention can be erected at one time, and more than one joint rotation axis 55 of the six-axis robot arm 5 can be completed. Error measurement.

Through the foregoing design, the present invention can complete the measurement of the joint rotation axis 55 of the entire six-axis robot arm 5, and use the computer 6 for analysis, thereby knowing the angular positioning error, so that the offset value can be calculated by the computer 6 to generate compensation. Therefore, the joint rotation shaft 55 can obtain correct compensation before processing, and since the invention can overcome the environmental interference of the conventional optical system by using the angle sensor 2, the installation is fast, the volume is small, and the carrying is convenient; The heart and warm-up measurement requires only 1/3 of the conventional optical measurement time. The five joint rotation axes 55 of the six-axis robot arm 5 can be measured twice, and compared with the conventional optical measurement system, the lightning detector and the mirror There is a measurement dead angle, and the measuring system of the invention has no such problem, and the measuring angle range is large, thereby improving the measuring quality and accuracy, so as to improve the precision of the subsequent processing.

The detailed description of the preferred embodiments of the present invention is intended to be limited to the scope of the invention, and is not intended to limit the scope of the invention. The patent scope of this case.

In summary, this case is not only innovative in terms of space type, but also can enhance the above-mentioned multiple functions compared with conventional articles. It should fully comply with the statutory invention patent requirements of novelty and progressiveness, and apply for it according to law. Approved this invention patent application, in order to invent invention, to the sense of virtue.

1‧‧‧ Positioning indexer

11‧‧‧Adapter plate

2‧‧‧ Angle Sensor

5‧‧‧ Six-axis robot

55‧‧‧ Joint rotation axis

Claims (8)

The utility model relates to a mechanical arm rotating shaft measuring system, which comprises a positioning indexing device and an angle sensor, and the angle sensor and the positioning indexing device are connected to a computer capable of capturing and calculating, and the computer has built-in analysis error. The soft body; wherein: the positioning indexer is disposed on a tail end of one of the mechanical arm rotation axes, and the positioning indexer has an adapter plate coupled with the joint rotation axis of the mechanical arm tail end, which is tied to the parameter Reversely rotating the equal angles of the plurality of ranging points; the angle sensor is fixed on the positioning indexer, and has a standard zero point, according to the plurality of angle data output by the angle sensor, successively and standard zero point analysis Angle error, and then obtain multiple angular offset values of multiple ranging points and use them as positioning error measurement of joint rotation axis; thereby, the group constitutes a simple and multi-axis measurement robot arm rotation axis quantity Test system. The robot arm rotating shaft measuring system according to claim 1, wherein the positioning indexer has a minimum rotation degree of 5 degrees, and the 360 degree rotation is performed, and the positioning accuracy of the positioning indexer is ±5 μm/m. It has a fairly small amount of variation. The robot arm rotating shaft measuring system according to claim 1, wherein the positioning indexing device adopts a wired transmission interface of RS-232. The robot arm rotation axis measuring system described in claim 1 The angle sensor is fixed to the rotating end of the positioning indexer by a casing, and the housing of the angle sensor has a base for selectively locking the positioning indexer, and is formed on the base There is a dividing groove of the tapered portion, so that the adjusting groove is formed at one end by the dividing groove, and at least one adjusting bolt connecting the base is provided on the base for finely adjusting the adjusting portion by using the adjusting bolt The housing is further covered with a housing to protect the angle sensor on the base. The robot arm rotating shaft measuring system according to claim 1, wherein the angle sensor is capable of measuring a horizontal angle of 0±.00035 degrees. The robot arm rotating shaft measuring system according to claim 1 or 5, wherein the angle sensor adopts an RS-485 wired transmission interface, and has a multi-point transmission function. A measuring method for measuring a rotating shaft measuring system of a mechanical arm, which is used for measuring an error of a rotating shaft of each joint of a six-axis robot arm, comprising: step 1, a step of installing a positioning indexer, directly connecting the positioning indexer It is mounted on the tail end of the joint rotation shaft to be measured by the robot arm, and the positioning indexer is coupled to the joint rotation shaft through the adapter plate, and the angle sensor is mounted on the positioning indexer; Step 2, an angle sensor In the zero return step of the origin, the angle sensor is used as the calibration index of the positioning indexer; and in step 3, the step of setting the distance of the joint rotation axis is performed on the computer. The stroke parameter setting of the plurality of angles of the plurality of ranging points of the joint rotation axis; step 4, setting the distance measuring point of the positioning indexer, setting the reverse rotation angle of the plurality of ranging points of the positioning indexer for the computer to prepare to start Recording the offset value of each rotation angle of the plurality of ranging points; in step 5, the step of rotating the joint rotation axis in the forward direction, automatically executing the output parameters to the joint rotation axes through the computer, so that the joints of the robot arm rotate The axis performs a plurality of ranging points for the forward rotation angle according to the set stroke; in step 6, the angle sensor range determining step, the computer determines whether the angle sensor exceeds the measurement range, and if the measurement range is not exceeded, Perform step 6 to judge the process again. Otherwise, if the measurement range has been exceeded, perform the following step 7; in step 7, a positioning indexer reverses the sequential rotation step, and after the computer determines that the angle sensor exceeds the measurement range, the positioning indexer is made. Reversely rotating the angles of the plurality of ranging points according to the stroke, thereby outputting a plurality of angle data of the plurality of ranging points; and step 8, the angle shifting of the angle sensor a value step, according to the plurality of angle data output by the positioning indexer, sequentially analyzing the angle error with the standard zero point, and sequentially obtaining a plurality of angular offset values of the plurality of ranging points, thereby indicating the joint rotation axis and the positioning indexer The angle difference relationship; continue, return to step 5 to make the joint rotation axis perform the next rotation point for the positive rotation angle; if the joint rotation axis completes the rotation point, the following step 9 is performed; Step 9, a stroke determining step, after the angle sensor obtains the angle offset value step, whether to complete the stroke, if the measurement stroke has not been completed, return to the joint rotation axis forward sequential rotation step, and sequentially perform the foregoing The measurement process, if the measurement stroke has been completed, proceeds to the following step 10; step 10, an analysis error value step, after completing the entire measurement stroke, successively obtains multiple angular offset value outputs of the plurality of ranging points. When the mechanical arm joint rotation axis rotates clockwise by a fixed angle, the angle sensor mounted on the positioning indexer can capture the horizontal error value by the angle sensor by inverting a fixed angle through the positioning indexer, and Complete the error measurement of more than one joint rotation axis of the six-axis robot. The measuring method of the mechanical arm rotating shaft measuring system according to the seventh aspect of the invention, wherein the angle sensor of the angle sensor returning to the zero point uses a reference horizontal plane as a positioning indexing device correction reference.