Method for quickly calibrating zero point of ABB robot on assembly line

Abstract

The invention relates to an assembly line ABB robot zero point rapid calibration method, and belongs to the technical field of industrial robots. According to the method, the problems of low efficiency, high cost, high difficulty, high error rate and the like in robot zero calibration work are solved by manufacturing tooling'adjustable mechanical stop blocks and stop columns' and optimizing the working processes of'pre-calibration preparation, rapid zero calibration, verification and fine adjustment ', the working time is shortened to be within 30 minutes from 2 hours, the quality is guaranteed to be 100%, and the working efficiency is greatly improved. The method is provided for high-efficiency, high-quality, low-cost and safe robot zero point rapid calibration.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial robots, and relates to a kind of assembly production line ABB robot zero point rapid calibration method. BACKGROUND

[0002] The electromagnetic valve automatic production line undertakes the assembly task of the electromagnetic valve assembly of liquid rocket engine, undertakes the batch production of attitude control direct acting electromagnetic valve, and the electromagnetic valve automatic assembly production line combines automation, digitization and special equipment, improves assembly efficiency and product quality consistency.ABB (Asea Brown Boveri) robot as the core execution unit in the electromagnetic valve automatic production line, its positioning accuracy directly affects the product assembly quality, the zero point position will be offset after long time operation or accidental power failure of the robot, resulting in assembly misplacement, equipment collision and other problems, the following problems exist in the traditional zero point calibration process:

[0003] (1) Low efficiency: time-consuming up to 2-4 hours;

[0004] (2) High cost: automatic production line needs to be operated;

[0005] (3) High error rate: robot shaft I~shaft VI, the bottom plate and the rotating disc can rotate a whole circle, the rotation angle is often added by 360° in the calibration process, and the cable and air pipe are easy to twist and even break. SUMMARY

[0006] The technical problem solved by the application is to overcome the shortcomings of the prior art, and the application provides a kind of assembly production line ABB robot zero point rapid calibration method.

[0007] The technical solution of the application is: a kind of assembly production line ABB robot zero point rapid calibration method, including the following steps:

[0008] Robot pre-calibration preparation;

[0009] Install assembly tooling at the robot joint, including adjustable mechanical stop block and stop column;

[0010] Reset the position feedback encoder signal of the robot;

[0011] Manually rotate to align the zero point lines of the rotating disc and the bottom plate at the robot axis to be calibrated;

[0012] Set the robot teach pendant control board to "manual mode", select "update tachometer counter", check the axis to be calibrated, issue "zero point calibration" instruction through calibration software, and write the current pose into zero point parameter table for data locking;

[0013] Verify the torque eligibility of each axis of the robot;

[0014] Check the robot motion point deviation, and adjust the zero point offset of each axis when the deviation does not meet the requirements.

[0015] Trial operation, monitor positioning accuracy and torque fluctuation, and complete calibration work when there is no abnormality.

[0016] Further, the adjustable mechanical stop block is installed on the chassis of each axis of the robot capable of 360° rotation; the stop column is installed on the rotating disc; the adjustable mechanical stop block and the stop column cooperate to limit the chassis and the rotating disc at the joint of the robot from rotating a full circle.

[0017] Further, the material of the adjustable mechanical stop block is quenched and tempered steel; the material of the stop column is quenched and tempered steel.

[0018] Further, the adjustable mechanical stop block comprises a base, a left end structure and a right end structure, the left end structure and the right end structure are symmetrically arranged at both ends of the base and are connected perpendicularly thereto; the base is fixed on the chassis; the outer sides of the left end structure and the right end structure are designed with circular arc grooves.

[0019] Further, the stop column is of a T-shaped structure, comprising a crossbeam and a column, which are connected perpendicularly; the crossbeam is fixed on the rotating disc.

[0020] Further, the column and the left end structure and the right end structure of the adjustable mechanical stop block are matched in size with the circular arc grooves on the outer sides thereof, and cooperate to realize stroke limiting.

[0021] Further, the robot pre-calibration preparation comprises cable and air pipe inspection and robot preheating; the cable and air pipe inspection is used to make the cables and air pipes fixed on each axis of the robot in an expanded state; the robot preheating is used to eliminate the influence of thermal deformation on the zero point accuracy of the equipment.

[0022] Further, the process of resetting the position feedback encoder signal of the robot is that the position feedback encoder values of each axis are cleared by calling the robot zero point calibration instruction.

[0023] Further, the check of the robot motion point deviation is ≤0.02mm.

[0024] Further, the adjustment of the zero point offset of each axis is realized by calling the fine adjustment instruction in the robot calibration software.

[0025] The beneficial effects of the present application compared with the prior art are:

[0026] (1) The present application proposes a kind of assembly production line ABB robot zero point fast calibration method, improves calibration efficiency by mechanical and software coordination calibration, and the time used for calibration is 20-30 min.

[0027] (2) The present invention does not require stopping the work of other parts of the automatic production line during calibration. The calibration work can be completed before the robot is used. The downtime cost is reduced by about 5,000 yuan per calibration.

[0028] (3) The present invention designs adjustable mechanical blocks and stops to be installed at the robot's axes I to VI; the adjustable mechanical blocks are installed on the chassis at the robot's 360° rotatable axis, and the stops are installed on the rotating disk. The two restrict the robot's joints from rotating a full circle between the chassis and the rotating disk; through mechanical and software coordinated calibration, the superposition of 360° rotation angles during the calibration process is avoided, thus preventing damage to the equipment. Attached Figure Description

[0029] Figure 1 A schematic diagram of each axis of the robot;

[0030] Figure 2 This is a structural diagram of the adjustable mechanical stop block of the present invention;

[0031] Figure 3 This is a structural diagram of the retaining column of the present invention;

[0032] Figure 4 This is a schematic diagram of the tooling installation of the present invention. Detailed Implementation

[0033] The present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments.

[0034] Example 1:

[0035] ABB robots consist of a base, rotary joints, links, end effectors, cable management system, teach pendant, controller, servo drive system, sensors, and position feedback encoders.

[0036] like Figure 1 The diagram shows the axes of the ABB robot's rotary joints, from axis I1 to axis VI6.

[0037] The zero-point calibration steps are as follows: After the machine is warmed up, install the assembly fixture, use the ZeroCalib Quick command in RobotStudio (the robot's factory-installed calibration software) to clear the speed counter value, then set the robot to manual mode, enter the calibration interface, select the manual calibration method, select the robot, select the axis to be calibrated, align the zero-point scale lines of each axis, and execute the update.

[0038] A method for rapid zero-point calibration of an ABB robot on an assembly line includes:

[0039] (1) Design and make assembly tooling, including adjustable mechanical stop 9 and stop column 8;

[0040] As shown in Figure 2 Adjustable mechanical stop 9, including base and left and right end structure, left and right end structure and base perpendicular to each other, the base is provided with threaded hole, fixed on the chassis 10 through screw; The outer side of the left and right end structure is designed with a circular arc groove, so that it is in contact with the column surface of the stop column 8.

[0041] As shown in Figure 3 Stop column 8 is T-shaped structure, including beam and column, perpendicular connection; The beam is provided with threaded hole, fixed on the rotating disc 7 through screw; The column is matched with the size of the circular arc groove of the adjustable mechanical stop 9, and the two are matched to realize the stroke limiting.

[0042] The materials of adjustable mechanical stop 9 and stop column 8 are both quenched and tempered steel 2Cr13, which is quenched and tempered.

[0043] Purpose: To prevent the rotation of shaft I1 and VI6, and avoid the superposition of 360° rotation angle in the calibration process.

[0044] (2) Pre-calibration preparation

[0045] Check the cable and air pipe, so that the cable and air pipe fixed on the robot shaft are in a relaxed state.

[0046] As shown in Figure 4 Adjustable mechanical stop 9 and stop column 8 are installed on the robot shaft I1 to VI6. Among them, the adjustable mechanical stop 9 is installed on the chassis 10 of the robot shaft I1 which can rotate 360°, and the stop column 8 is installed on the rotating disc 7, which limits the whole rotation between the chassis 10 and the rotating disc 7 of the joint of the robot, avoiding the superposition of 360° rotation angle in the calibration process.

[0047] The robot is preheated for 10 minutes to make the temperature of each shaft stable at the normal working temperature of 25±2℃, so as to eliminate the influence of thermal deformation on the zero point accuracy of the equipment.

[0048] Through pre-calibration preparation, the cable and air pipe of the robot are kept in good working condition and the service life is prolonged.

[0049] (3) Optimization of quick zero calibration process

[0050] Step 1: Encoder signal reset, clear the encoder value of each shaft by calling the instruction ZeroCalib Quick (robot zero calibration instruction) in ABB RobotStudio (robot simulation and programming software).

[0051] Step 2: two disc alignment, manual mode rotation robot, so that the axis I1 rotation disc 7 mark line with the bottom disc 10 mark line alignment.

[0052] Step 3: data locking, the key knob on the teach pendant control board is turned to manual mode, the "calibration" option is entered, the "manual zero calibration" mode is selected, the "update tachometer counter" is selected, the axis I1 is checked, the "re-calibration" is clicked, and the current pose is written into the zero point parameter table.

[0053] Step 4: repeat steps 2-3 to calibrate axis II2-VI6.

[0054] Step 5: check the torque eligibility of each axis.

[0055] Step 6: run the robot motion point deviation, adjust the zero point offset of each axis by calling FineTune (fine tuning instruction).

[0056] Step 7: trial run, run the product assembly program, monitor the positioning accuracy (≤0.02mm) and torque fluctuation, ensure no abnormality, complete the calibration work.

[0057] Verify the debugging by laser ranging auxiliary, use portable laser range finder (Leica DISTO) to inspect the relative position between tool center point and assembly tool ≤0.02mm, when the deviation >0.02mm, adjust the zero point offset of each axis by FineTune program.

[0058] Compared with the prior art, the calibration efficiency is improved, and the calibration time is now 20-30min; the calibration does not need to stop the work of other parts of the automatic production line, and the calibration work can be completed before the robot single machine is used; mechanical and calibration coordinate calibration, combined with mechanical block physical limit calibration software instruction reset, avoiding the possible rotation angle superposition 360° of traditional method; through pre-calibration preparation, the robot cable and air pipe are kept in good working condition and the service life is prolonged; improve safety, prevent program errors or other abnormal conditions from causing continuous 360° rotation of the equipment, causing personal and equipment damage; single calibration reduces downtime cost by about 5000 yuan.

[0059] The application is suitable for IRB 6700, IRB 2600 and other series of robots, and has been tested and implemented in automatic assembly production line of storage box, automatic assembly production line of thrust chamber and other ABB robot zero point fast calibration.

[0060] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications to the technical solutions of the present application using the disclosed methods and technical contents without departing from the spirit and scope of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application shall fall within the protection scope of the technical solutions of the present application.

Claims

1. A method for rapid zero-point calibration of an ABB robot on an assembly line, characterized in that, Includes the following steps: Robot pre-calibration preparation; Install assembly fixtures at the robot joints, including adjustable mechanical stops (9) and stops (8); Reset the robot position feedback encoder signal; Manually rotate the rotating disk (7) at the axis to be calibrated of the robot to align with the zero mark line of the chassis (10); Set the robot teach pendant control board to "manual mode", select "update speed counter", check the axis to be calibrated, issue the "zero point calibration" command through the calibration software, write the current pose into the zero point parameter table, and lock the data; Verify the torque of each axis of the robot to ensure it meets the requirements; Check the deviation of the robot's motion points, and adjust the zero-point offset of each axis if the deviation does not meet the requirements; During trial operation, monitor positioning accuracy and torque fluctuations. If no abnormalities are found, complete the calibration process.

2. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 1, characterized in that, The adjustable mechanical stop (9) is installed on the chassis (10) at each axis of the robot that can rotate 360°; the stop (8) is installed on the rotating disk (7); the adjustable mechanical stop (9) and the stop (8) work together to prevent the robot's joint chassis (10) from rotating a full circle with the rotating disk (7).

3. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 2, characterized in that, The adjustable mechanical stop (9) is made of tempered steel; the stop post (8) is made of tempered steel.

4. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 2, characterized in that, The adjustable mechanical stop (9) includes a base, a left end structure, and a right end structure. The left end structure and the right end structure are symmetrically arranged at both ends of the base and are vertically connected to it. The base is fixed on the chassis (10). The outer sides of the left end structure and the right end structure are both designed with arc grooves.

5. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 4, characterized in that, The aforementioned retaining post (8) is a T-shaped structure, including a crossbeam and a column, which are vertically connected; the crossbeam is fixed on the rotating disk (7).

6. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 5, characterized in that, The dimensions of the arc grooves on the outer sides of the left and right ends of the column and the adjustable mechanical stop (9) are matched, and the two work together to achieve stroke limit.

7. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 1, characterized in that, The robot pre-calibration preparation includes cable and air pipe inspection and robot preheating; cable and air pipe inspection is used to ensure that the externally fixed cables and air pipes on each axis of the robot are in a stretched state; robot preheating is used to eliminate the influence of thermal deformation on the zero-point accuracy of the equipment.

8. The method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 1, characterized in that, The process of resetting the robot position feedback encoder signal is as follows: by calling the robot zero-point calibration command, the values ​​of the position feedback encoders of each axis are cleared.

9. A method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 1, characterized in that, The deviation of the movement point of the inspection robot is ≤0.02mm.

10. A method for rapid zero-point calibration of an ABB robot on an assembly line according to claim 1, characterized in that, The adjustment of the zero-point offset of each axis is achieved by calling the fine-tuning command in the robot calibration software.

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