Zero calibration method for seven-axis robot

Abstract

The invention relates to the field of household kitchens, and discloses a zero calibration method for a seven-axis robot, which comprises the following specific steps: step 1, mechanical zero calibration: firstly, moving each joint of the robot to a mechanical zero position, and ensuring that the joints of the robot are at initial positions and a mechanical structure is not interfered or deformed by the outside; step 2, calibrating a joint angle; step 3, calibrating the tool end, calibrating the position and the posture of the tool end, and moving the tool end to a known position; step 4, calibrating a base coordinate system; 5, calibrating and verifying; and step 6, adjusting and optimizing. The positioning and posture precision of the robot can be improved by calibrating a mechanical structure, a joint angle and a tool end posture, so that the accuracy in the production process is improved, the accuracy and the stability of an operation space of the robot are ensured by calibrating a base coordinate system, and motion instability and working errors caused by posture deviation are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of robots, and in particular to a zero position calibration method for a seven-axis robot. Background Art

[0002] A seven-axis robot is an industrial robot with seven degrees of freedom (axes) that can perform various tasks in a more flexible way in three-dimensional space. These degrees of freedom are usually composed of seven joints, enabling the robot to achieve more complex movements and operations, such as more flexible posture control, wider workspace coverage, and more complex path planning and execution capabilities. Seven-axis robots are often used in applications that require high precision and flexibility, such as automated assembly, precision machining, material handling, and complex operating tasks. The zero calibration method is a process used to calibrate the position and posture of a robot or other automated system. It aims to ensure that the robot can accurately position and control its posture when performing tasks, thereby improving work accuracy and stability.

[0003] However, certain errors are inevitable in the manufacturing and assembly process of existing mechanical structures, such as joint clearance, looseness of the transmission system, etc. These errors will cause positioning deviation and posture error in the robot during movement. Therefore, a zero-position calibration method for a seven-axis robot is proposed. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a zero-position calibration method for a seven-axis robot, which solves the problem of certain errors existing in the manufacturing and assembly processes of the existing mechanical structures.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A zero position calibration method for a seven-axis robot comprises the following specific steps:

[0006] Step 1: Mechanical zero position calibration: First, move each joint of the robot to the mechanical zero position to ensure that the joints of the robot are in the initial position and the mechanical structure is not disturbed or deformed by external factors.

[0007] Step 2: Joint angle calibration: Use the robot control system and related software tools to calibrate the angle of each joint, set the position of each joint driver to zero, and record the current joint angle of the robot;

[0008] Step 3: Tool end calibration: To calibrate the position and posture of the tool end, the tool end needs to be moved to a known position and its position and posture are measured by sensors or external measuring equipment.

[0009] Step 4: Base coordinate system calibration: determine the base coordinate system of the robot, that is, the origin and coordinate axis direction of the robot's operating space, move the robot end effector to a known position, and set the origin and direction of the base coordinate system;

[0010] Step 5, calibration verification: After the robot is calibrated, verification is required to ensure the accuracy and reliability of the calibration, which includes moving the robot to different positions and postures, and using measurement tools and sensors to verify that the robot's movement is consistent with expectations;

[0011] Step 6, Adjustment and Optimization: Based on the verification results, adjust and optimize the robot's calibration parameters. This may involve recalibrating certain joints or tool ends, or adjusting the settings of the base coordinate system to ensure that the robot's motion and posture meet the requirements.

[0012] Preferably, in the step 2, before performing the joint angle calibration, it is necessary to ensure that the robot is in a safe state and has been powered off or in an emergency stop state. At the same time, check whether the mechanical structure of the robot is intact and whether the joint sensors are working properly. Start the control system of the robot, select or enter the joint angle calibration mode in the control system, set the zero position: calibrate each joint in turn, first, set the driver position of the selected joint to the zero position, when performing this operation, the power of the robot should be in the off state, and it is necessary to operate according to the operating steps provided by the robot manufacturer, record the angle value: after setting the joint driver position to the zero position, record the current joint angle value of the robot, and implement it through the monitoring interface and related software tools in the control system, Ensure that the recorded angle values ​​are accurate and consistent with the actual physical state of the robot. Verify the calibration results: After completing the angle calibration of all joints, verify the calibration results, which includes moving the robot to different positions and postures, and observing whether the joint angles are consistent with expectations. If any abnormalities or unexpected situations are found, it is necessary to recheck the calibration process and make adjustments. Save the calibration parameters: After confirming that the calibration results are correct, save the parameters of the joint angle calibration. Saving the calibration parameters can ensure that the previous calibration state can be maintained when the robot is restarted or recalibrated. Exit calibration mode: After completing all calibration steps and saving the parameters, exit the joint angle calibration mode, ensure that the robot returns to normal operation, and perform necessary safety checks and tests.

[0013] Preferably, in step three, before calibrating the tool end, ensure that the robot and the tool end are in a safe state and have been powered off, and check whether the mechanical structure of the tool end is intact and whether the sensor is working properly. Determine a known, easily measurable reference point as a reference for tool end calibration, use the robot control system to move the tool end to the known reference point position, use the sensor to measure the position and posture of the tool end, which includes the coordinate position and posture of the tool end, and input the measured tool end position and posture parameters into the robot control system. The purpose of calibrating the tool end parameters is to align the coordinate system of the robot control system with the actual position and posture of the tool end. After completing the calibration of the tool end parameters, move the tool end to other positions and observe whether its position and posture are as expected, ensuring that the tool end can be accurately positioned and operated when performing tasks. After confirming that the calibration results are correct, save the tool end calibration parameters. Saving the calibration parameters can ensure that the previous calibration state can be maintained when the robot is restarted or recalibrated. After completing the tool end calibration and saving the parameters, exit the calibration mode to ensure that the robot returns to normal operating state, and perform necessary safety checks and tests.

[0014] Preferably, in step 4, before performing the base coordinate system calibration, ensure that the robot is in a safe state and has been powered off. At the same time, confirm that the robot control system can receive and process calibration instructions and that the actuator is in normal working condition. Determine a known and easily identifiable reference point as the origin of the base coordinate system. Use the robot control system to move the end effector to the known reference point position, determine the direction of the coordinate axis in the robot operation space, use the right-hand coordinate system to determine the positive direction and direction of the X, Y, and Z axes to ensure the consistency of subsequent operations. At the reference point, set the origin of the base coordinate system in the robot control system to the current position of the end effector. Determine the direction of the coordinate axis according to actual needs and working scenarios. For some applications, it is necessary to point the Z axis to the direction of gravity, while for other applications, it may be necessary to determine different coordinate axis directions based on operational convenience. After confirming that the base coordinate system is set correctly, save the base coordinate system parameters. Saving the base coordinate system parameters can ensure that the previously set reference state can be maintained when the robot is restarted or recalibrated. Move the end effector to other positions and observe whether its position in the robot operation space is as expected to ensure that the robot can accurately locate and perform tasks.

[0015] Preferably, in step five, a series of verification points are determined, and these points should cover different positions and postures in the robot's operating space. These points can be pre-defined fixed positions or positions that need to be reached in actual work tasks. The robot control system is used to move the robot to the predetermined position and posture of each verification point, ensuring that the robot stops after reaching each verification point, and that the end effector position and posture are consistent with expectations. A suitable measuring tool or sensor is used at each verification point to verify the robot's position and posture. The tool uses a laser rangefinder, a camera system, and an encoder to record the actual position and posture of each verification point, as well as the expected position and posture, and compares the actual results with the expected results to determine the difference or deviation between them.

[0016] Preferably, in step six, first, carefully analyze the previous verification results, determine the deviations or errors of the robot in different positions and postures, and determine the aspects that need to be adjusted and optimized. According to the verification results, determine the calibration parameters that need to be adjusted and optimized. The verification results show that there are deviations in the robot joints or tool ends, and these parts need to be recalibrated. If the verification results show that the robot's base coordinate system is incorrectly set, it is necessary to adjust the setting of the base coordinate system, which involves relocating the origin of the robot's base coordinate system, adjusting the direction and rotation angle of the base coordinate system, and performing actual adjustment operations on the robot according to the determined adjustment parameters. After the adjustment is completed, verify again to ensure that the adjustment effect meets the requirements, move the robot to different positions and postures, and use measuring tools or sensors to verify whether the robot's motion and posture are consistent with expectations. If the verification results still do not meet the requirements, it is necessary to continue to optimize the calibration parameters and repeat the above steps until the robot's motion and posture meet the requirements.

[0017] The present invention provides a zero position calibration method for a seven-axis robot. It has the following beneficial effects:

[0018] The present invention can improve the positioning and posture accuracy of the robot by calibrating the mechanical structure, joint angles and tool end posture, thereby improving the accuracy in the production process. By calibrating the base coordinate system, the accuracy and stability of the robot's operating space can be ensured, and the motion instability and working errors caused by posture deviation can be reduced. Optimizing the robot's operating parameters and posture calibration can reduce the adjustment and correction time in the production process, thereby improving production efficiency and output effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Embodiment 1:

[0022] like Figure 1 As shown, an embodiment of the present invention provides a zero position calibration method for a seven-axis robot, comprising the following steps:

[0023] Step 1: Mechanical zero position calibration: First, move each joint of the robot to the mechanical zero position to ensure that the joints of the robot are in the initial position and the mechanical structure is not disturbed or deformed by external factors.

[0024] Step 2: Joint angle calibration: Use the robot control system and related software tools to calibrate the angle of each joint, set the position of each joint driver to zero, and record the current joint angle of the robot;

[0025] Step 3: Tool end calibration: To calibrate the position and posture of the tool end, the tool end needs to be moved to a known position and its position and posture are measured by sensors or external measuring equipment.

[0026] Step 4: Base coordinate system calibration: determine the base coordinate system of the robot, that is, the origin and coordinate axis direction of the robot's operating space, move the robot end effector to a known position, and set the origin and direction of the base coordinate system;

[0027] Step 5, calibration verification: After the robot is calibrated, verification is required to ensure the accuracy and reliability of the calibration, which includes moving the robot to different positions and postures, and using measurement tools and sensors to verify that the robot's movement is consistent with expectations;

[0028] Step 6, Adjustment and Optimization: Based on the verification results, adjust and optimize the robot's calibration parameters. This may involve recalibrating certain joints or tool ends, or adjusting the settings of the base coordinate system to ensure that the robot's motion and posture meet the requirements.

[0029] In step 2, before calibrating the joint angles, you need to ensure that the robot is in a safe state and has been powered off or in an emergency stop state. At the same time, check whether the robot's mechanical structure is intact and whether the joint sensors are working properly. Start the robot's control system, select or enter the joint angle calibration mode in the control system, and set the zero position: calibrate each joint in turn. First, set the drive position of the selected joint to zero. When performing this operation, the robot's power should be turned off, and you need to follow the operating steps provided by the robot manufacturer. Record the angle value: After setting the joint drive position to zero, record the robot's current joint angle value. This is achieved through the monitoring interface and related software tools in the control system to ensure that the angle value is recorded. The recorded angle values ​​are accurate and consistent with the actual physical state of the robot. Verify the calibration results: After completing the angle calibration of all joints, verify the calibration results, which includes moving the robot to different positions and postures, and observing whether the joint angles are consistent with expectations. If any abnormalities or unexpected situations are found, it is necessary to recheck the calibration process and make adjustments. Save the calibration parameters: After confirming that the calibration results are correct, save the parameters of the joint angle calibration. Saving the calibration parameters can ensure that the previous calibration state can be maintained when the robot is restarted or recalibrated. Exit calibration mode: After completing all calibration steps and saving parameters, exit the joint angle calibration mode, ensure that the robot returns to normal operation, and perform necessary safety checks and tests.

[0030] In step three, before calibrating the tool end, ensure that the robot and the tool end are in a safe state and the power is off. At the same time, check whether the mechanical structure of the tool end is intact and whether the sensor is working properly. Determine a known, easy-to-measure reference point as the reference for tool end calibration. Use the robot control system to move the tool end to the known reference point position. Use the sensor to measure the position and posture of the tool end, which includes the coordinate position and posture of the tool end. Input the measured tool end position and posture parameters into the robot control system. The purpose of calibrating the tool end parameters is to align the coordinate system of the robot control system with the actual position and posture of the tool end. After completing the calibration of the tool end parameters, move the tool end to other positions and observe whether its position and posture are as expected, ensuring that the tool end can be accurately positioned and operated when performing tasks. After confirming that the calibration results are correct, save the tool end calibration parameters. Saving the calibration parameters can ensure that the previous calibration state can be maintained when the robot is restarted or recalibrated. After completing the tool end calibration and saving the parameters, exit the calibration mode to ensure that the robot returns to normal operation and perform necessary safety checks and tests.

[0031] In step 4, before calibrating the base coordinate system, ensure that the robot is in a safe state and has been powered off. At the same time, confirm that the robot control system can receive and process calibration instructions and that the actuator is in normal working condition. Determine a known and easily identifiable reference point as the origin of the base coordinate system. Use the robot control system to move the end effector to the known reference point position, determine the direction of the coordinate axis in the robot operation space, use the right-hand coordinate system, determine the positive direction and direction of the X, Y, and Z axes to ensure the consistency of subsequent operations. At the reference point, set the origin of the base coordinate system in the robot control system to the position of the current end effector. Determine the direction of the coordinate axis according to actual needs and work scenarios. For some applications, the Z axis needs to point to the direction of gravity, while for other applications, different coordinate axis directions may need to be determined based on operational convenience. After confirming that the base coordinate system is set correctly, save the base coordinate system parameters. Saving the base coordinate system parameters can ensure that the previously set reference state can be maintained when the robot is restarted or recalibrated. Move the end effector to other positions and observe whether its position in the robot operation space is as expected to ensure that the robot can accurately locate and perform tasks.

[0032] In step five, determine a series of verification points, which should cover different positions and postures in the robot's operating space. These points can be pre-defined fixed positions or positions that need to be reached in actual work tasks. Use the robot control system to move the robot to the predetermined position and posture of each verification point, ensure that the robot stops after reaching each verification point, and that the end effector position and posture are consistent with expectations. Use appropriate measurement tools or sensors at each verification point to verify the robot's position and posture. The tools use laser rangefinders, camera systems, and encoders to record the actual position and posture of each verification point, as well as the expected position and posture. Compare the actual results with the expected results to determine the differences or deviations between them.

[0033] In step six, first, carefully analyze the previous verification results, determine the deviation or error of the robot in different positions and postures, and determine the aspects that need to be adjusted and optimized. According to the verification results, determine the calibration parameters that need to be adjusted and optimized. The verification results show that there are deviations in the robot joints or tool ends, and these parts need to be recalibrated. If the verification results show that the robot's base coordinate system is not set correctly, the base coordinate system settings need to be adjusted, which involves relocating the robot's base coordinate system origin, adjusting the direction and rotation angle of the base coordinate system, and performing actual adjustment operations on the robot according to the determined adjustment parameters. After the adjustment is completed, verify again to ensure that the adjustment effect meets the requirements, move the robot to different positions and postures, and use measuring tools or sensors to verify whether the robot's motion and posture are consistent with expectations. If the verification results still do not meet the requirements, it is necessary to continue to optimize the calibration parameters and repeat the above steps until the robot's motion and posture meet the requirements.

[0034] Table 1: Method flow chart

[0035]

[0036]

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A zero position calibration method for a seven-axis robot, characterized in that: The specific steps include: Step 1: Mechanical zero position calibration: First, move each joint of the robot to the mechanical zero position to ensure that the joints of the robot are in the initial position and the mechanical structure is not disturbed or deformed by external factors. Step 2: Joint angle calibration: Use the robot control system and related software tools to calibrate the angle of each joint, set the position of each joint driver to zero, and record the current joint angle of the robot; Step 3: Tool end calibration: To calibrate the position and posture of the tool end, the tool end needs to be moved to a known position and its position and posture are measured by sensors or external measuring equipment. Step 4: Base coordinate system calibration: determine the base coordinate system of the robot, that is, the origin and coordinate axis direction of the robot's operating space, move the robot end effector to a known position, and set the origin and direction of the base coordinate system; Step 5, calibration verification: After the robot is calibrated, verification is required to ensure the accuracy and reliability of the calibration, which includes moving the robot to different positions and postures, and using measurement tools and sensors to verify that the robot's movement is consistent with expectations; Step 6, Adjustment and Optimization: Based on the verification results, adjust and optimize the robot's calibration parameters. This may involve recalibrating certain joints or tool ends, or adjusting the settings of the base coordinate system to ensure that the robot's motion and posture meet the requirements.

2. A zero position calibration method for a seven-axis robot according to claim 1, characterized in that: In the step 2, before performing joint angle calibration, it is necessary to ensure that the robot is in a safe state and has been powered off or in an emergency stop state. At the same time, check whether the robot's mechanical structure is intact and whether the joint sensors are working properly. Start the robot's control system, select or enter the joint angle calibration mode in the control system, and set the zero position: calibrate each joint in turn. First, set the driver position of the selected joint to zero. When performing this operation, the power of the robot should be turned off, and it is necessary to follow the operating steps provided by the robot manufacturer. Record the angle value: After setting the joint driver position to zero, record the robot's current joint angle value, and implement it through the monitoring interface and related software tools in the control system to ensure The recorded angle values ​​are accurate and consistent with the actual physical state of the robot. Verify the calibration results: After completing the angle calibration of all joints, verify the calibration results, which includes moving the robot to different positions and postures, and observing whether the joint angles are consistent with expectations. If any abnormalities or unexpected situations are found, it is necessary to recheck the calibration process and make adjustments. Save the calibration parameters: After confirming that the calibration results are correct, save the parameters of the joint angle calibration. Saving the calibration parameters can ensure that the previous calibration state can be maintained when the robot is restarted or recalibrated. Exit calibration mode: After completing all calibration steps and saving parameters, exit the joint angle calibration mode, ensure that the robot returns to normal operation, and perform necessary safety checks and tests.

3. The zero position calibration method of a seven-axis robot according to claim 1, characterized in that: In the step three, before calibrating the tool end, ensure that the robot and the tool end are in a safe state and have been powered off. At the same time, check whether the mechanical structure of the tool end is intact and whether the sensor is working properly. Determine a known, easily measurable reference point as a reference for tool end calibration. Use the robot control system to move the tool end to the known reference point position. Use the sensor to measure the position and posture of the tool end, which includes the coordinate position and posture of the tool end. Input the measured tool end position and posture parameters into the robot control system. The purpose of calibrating the tool end parameters is to align the coordinate system of the robot control system with the actual position and posture of the tool end. After completing the calibration of the tool end parameters, move the tool end to other positions and observe whether its position and posture are as expected, ensuring that the tool end can be accurately positioned and operated when performing tasks. After confirming that the calibration results are correct, save the tool end calibration parameters. Saving the calibration parameters can ensure that the previous calibration state can be maintained when the robot is restarted or recalibrated. After completing the tool end calibration and saving the parameters, exit the calibration mode to ensure that the robot returns to normal operation, and perform necessary safety checks and tests.

4. The zero position calibration method of a seven-axis robot according to claim 1, characterized in that: In the step 4, before performing the base coordinate system calibration, ensure that the robot is in a safe state and has been powered off. At the same time, confirm that the robot control system can receive and process calibration instructions and that the actuator is in normal working condition. Determine a known and easily identifiable reference point as the origin of the base coordinate system. Use the robot control system to move the end effector to the known reference point position, determine the direction of the coordinate axis in the robot operation space, use the right-hand coordinate system to determine the positive direction and direction of the X, Y, and Z axes to ensure the consistency of subsequent operations. At the reference point, set the origin of the base coordinate system in the robot control system to the current position of the end effector. Determine the direction of the coordinate axis according to actual needs and work scenarios. For some applications, the Z axis needs to point to the direction of gravity, while for other applications, different coordinate axis directions may need to be determined based on operational convenience. After confirming that the base coordinate system is set correctly, save the base coordinate system parameters. Saving the base coordinate system parameters can ensure that the previously set reference state can be maintained when the robot is restarted or recalibrated. Move the end effector to other positions and observe whether its position in the robot operation space is as expected to ensure that the robot can accurately locate and perform tasks.

5. The zero position calibration method of a seven-axis robot according to claim 1, characterized in that: In the step five, a series of verification points are determined, and these points should cover different positions and postures in the robot's operating space. These points can be pre-defined fixed positions or positions that need to be reached in actual work tasks. The robot control system is used to move the robot to the predetermined position and posture of each verification point, ensuring that the robot stops after reaching each verification point, and that the end effector position and posture are consistent with expectations. At each verification point, a suitable measuring tool or sensor is used to verify the robot's position and posture. The tool uses a laser rangefinder, a camera system, and an encoder to record the actual position and posture of each verification point, as well as the expected position and posture, and compares the actual results with the expected results to determine the difference or deviation between them.

6. A zero position calibration method for a seven-axis robot according to claim 1, characterized in that: In the step six, first, carefully analyze the previous verification results, determine the deviations or errors of the robot in different positions and postures, and determine the aspects that need to be adjusted and optimized. According to the verification results, determine the calibration parameters that need to be adjusted and optimized. The verification results show that there are deviations in the robot joints or tool ends, and these parts need to be recalibrated. If the verification results show that the robot's base coordinate system is not set correctly, it is necessary to adjust the settings of the base coordinate system, which involves relocating the origin of the robot's base coordinate system, adjusting the direction and rotation angle of the base coordinate system, and performing actual adjustment operations on the robot according to the determined adjustment parameters. After the adjustment is completed, verify again to ensure that the adjustment effect meets the requirements, move the robot to different positions and postures, and use measuring tools or sensors to verify whether the robot's motion and posture are consistent with expectations. If the verification results still do not meet the requirements, it is necessary to continue to optimize the calibration parameters and repeat the above steps until the robot's motion and posture meet the requirements.

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