CN117532618A - Calibration method of end load of robot arm and electronic equipment - Google Patents

Calibration method of end load of robot arm and electronic equipment Download PDF

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Publication number
CN117532618A
CN117532618A CN202311760706.3A CN202311760706A CN117532618A CN 117532618 A CN117532618 A CN 117532618A CN 202311760706 A CN202311760706 A CN 202311760706A CN 117532618 A CN117532618 A CN 117532618A
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China
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load
target
robot arm
motor
joint module
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CN202311760706.3A
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Chinese (zh)
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王延玉
倪健
林建雄
周嘉铨
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Changguangxi Intelligent Manufacturing Wuxi Co ltd
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Changguangxi Intelligent Manufacturing Wuxi Co ltd
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Priority to CN202311760706.3A priority Critical patent/CN117532618A/en
Publication of CN117532618A publication Critical patent/CN117532618A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J9/00—Programme-controlled manipulators
    • B25J9/16—Programme controls
    • B25J9/1679—Programme controls characterised by the tasks executed
    • B25J9/1692—Calibration of manipulator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
    • B25J19/0095—Means or methods for testing manipulators

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  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Manipulator (AREA)

Abstract

The embodiment of the application provides a calibration method of a tail end load of a robot arm and electronic equipment, wherein the method comprises the following steps: acquiring a target torque variation of the robot arm; determining the mass and centroid position of the load based on the target torque variation through a moment relation model; the target torque variation is the motor torque variation of the target joint module under the target posture before and after the robot arm is connected with the load; the moment relation model characterizes the association relation between the target torque variation and the heavy moment of the load. Therefore, the motion process of the robot arm can be simplified, the data processing capacity can be reduced, and the mass and mass center position of the load can be accurately calibrated.

Description

Calibration method of end load of robot arm and electronic equipment
Technical Field
The application relates to the technical field of robot arms, in particular to a calibration method of a terminal load of a robot arm and electronic equipment.
Background
With the advancement of industrial automation and intelligent processes, the application of the robot arm is more and more. In different application scenarios, the end-to-end tools of the robotic arm may not be the same, resulting in different mass and centroid positions of the end-load of the robotic arm. When the robot arm is actually used, the mass and the mass center of the load at the tail end of the robot arm are required to be calibrated, so that the moment of the load at the tail end of the robot arm is compensated, and the movement process of the robot arm can be accurately controlled.
In the conventional technology, two main methods for measuring the mass and the mass center position of a load are available. One is to construct a load model based on design parameters of the load, and determine the mass and centroid location of the load based on the load model. The method is complex in operation and high in cost. And the constructed load model is easy to have errors with the actual load, so that the measured mass and centroid position of the load has deviation with the mass and centroid position of the actual load. The other is to design an identification track and determine the mass and mass center position of the load by adopting a dynamic identification experiment, but the method is relatively complex in the process of designing the track, more track parameters need to be optimized, redundancy can occur in the identification process, and all parameters cannot be identified.
Disclosure of Invention
In view of the above problems in the prior art, the present application provides a calibration method for a tail end load of a robot arm and an electronic device, and a technical scheme adopted in an embodiment of the present application is as follows.
The first aspect of the application provides a calibration method for a terminal load of a robot arm, comprising the following steps:
acquiring a target torque variation of the robot arm;
determining the mass and centroid position of the load based on the target torque variation through a moment relation model;
The target torque variation is the motor torque variation of the target joint module under the target posture before and after the robot arm is connected with the load; the target joint module is any one of the joint modules of the robot arm;
the target gesture comprises a first gesture, a second gesture and a third gesture; when the robot arm is in a first posture, a first coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular; when the robot arm is in a second posture, a second coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular; in a third posture of the robot arm, a third coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are positioned on the same horizontal plane and are mutually perpendicular;
the moment relation model characterizes the association relation between the target torque variation and the heavy moment of the load; the centroid position comprises a first offset of the centroid on a first coordinate axis, a second offset of the centroid on a second coordinate axis and a third offset of the centroid on a third coordinate axis.
In some embodiments, obtaining the target torque variation for the robotic arm includes:
acquiring motor load torque of a target joint module when a robot arm connected with a load is in a target posture;
acquiring a motor no-load torque of a target joint module when the robot arm with no load is in a target attitude;
the target torque variation amount is determined based on the motor load torque and the motor no-load torque.
In some embodiments, obtaining the motor load torque of the target joint module with the load-connected robotic arm in the target pose comprises:
controlling a target joint module of a robot arm connected with a load to independently rotate through a target gesture, and determining the motor load current of the target joint module when the robot arm is in the target gesture;
and determining the motor load torque of the target joint module based on the motor load current.
In some embodiments, controlling a target joint module of a robot arm to which a load is connected to individually rotate through a target pose and determining a motor load current of the target joint module when the robot arm is in the target pose, comprises:
the method comprises the steps of controlling a target joint module connected with a loaded robot arm to independently rotate at a uniform speed along a clockwise direction to pass through a target gesture, and obtaining forward load current of a motor of the target joint module when the robot arm is in the target gesture;
The method comprises the steps of controlling a target joint module connected with a loaded robot arm to independently rotate at a constant speed along a counterclockwise direction to pass through a target gesture, and obtaining negative load current of a motor of the target joint module when the robot arm is in the target gesture;
the motor load current is determined based on an average of the motor positive load current and the motor negative load current.
In some embodiments, controlling the target joint module of the robot arm connected with the load to individually rotate at a uniform speed along the clockwise direction through the target gesture, and acquiring the motor forward load current of the target joint module when the robot arm is in the target gesture comprises:
the method comprises the steps of controlling a target joint module of a robot arm connected with a load to independently rotate at a uniform speed in a clockwise direction, acquiring first current data of a motor of the target joint module when the target joint module rotates to a target range, and determining the forward load current based on the first current data;
correspondingly, controlling the target joint module connected with the loaded robot arm to independently rotate at a constant speed along the anticlockwise direction to pass through the target gesture, and acquiring the negative load current of the motor of the target joint module when the robot arm is in the target gesture, comprising:
The method comprises the steps of controlling a target joint module of a robot arm connected with a load to independently rotate at a constant speed along a counterclockwise direction, acquiring second current data of a motor of the target joint module when the target joint module rotates to a target range, and determining the negative load current based on the second current data;
when the target joint module rotates to a target joint angle, the robot arm is in a target posture, and the target joint angle is a middle value of the target range.
In some embodiments, obtaining the motor no-load torque of the target joint module with the non-load connected robotic arm in the target pose comprises:
and determining the motor idle torque of the target joint module when the robot arm with the unconnected load is in the target posture through a dynamic model.
In some embodiments, obtaining the target torque variation for the robotic arm includes:
acquiring a first torque variation, a second torque variation, a third torque variation, a fourth torque variation and a fifth torque variation;
the first torque variation comprises motor torque variation of the first joint module under a first posture before and after the robot arm is connected with a load; the second torque variation comprises motor torque variation of the first joint module under the other first posture before and after the robot arm is connected with a load; under the first gesture and the second gesture, the gesture of the end load of the robot arm is different, and the first coordinate axis of the load coordinate system and the motor axis of the first joint module are positioned on the same horizontal plane and are mutually perpendicular;
The third torque variation comprises motor torque variation of the second joint module under a first posture before and after the robot arm is connected with a load, and in the first posture, a first coordinate axis of a load coordinate system and a motor axis of the second joint module are positioned on the same horizontal plane and are mutually perpendicular;
the fourth torque variation comprises motor torque variation of the third joint module under the second posture before and after the robot arm is connected with the load; in the second posture, the second coordinate axis of the load coordinate system and the motor axis of the third joint module are positioned on the same horizontal plane and are mutually perpendicular;
the fifth torque variation comprises motor torque variation of the fourth joint module in a third posture before and after the robot arm is connected with the load, and in the third posture, a third coordinate axis of the load coordinate system and a motor axis of the fourth joint module are positioned on the same horizontal plane and are mutually perpendicular.
In some embodiments, determining the mass and centroid position of the load based on the target torque variation through a moment relation model comprises:
determining a mass of the load based on the first torque variation and the second torque variation through the torque relationship model;
Determining the first offset based on the third torque variation and the mass of the load by the torque relationship model;
determining the second offset based on the fourth torque variation and the mass of the load by the torque relationship model;
and determining the third offset based on the fifth torque variation and the mass of the load through the torque shutdown model.
In some embodiments, the moment relation model is expressed by the following formula:
Δτ＝mg(l+Δl)
wherein Δτ represents the target torque variation; m represents the mass of the load; g represents a gravitational constant; l represents the vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the target joint module; Δl represents the first offset amount, the second offset amount, or the third offset amount.
A second aspect of the present application provides an electronic device, at least comprising a memory and a processor, the memory having a program stored thereon, the processor implementing a method according to any of the embodiments above when executing the program on the memory.
According to the calibration method of the robot arm load, the target torque variation of the target robot arm is obtained, and the mass centroid position of the load can be determined based on the target torque variation through the moment relation model. Therefore, the motion process of the robot arm can be simplified, the data processing capacity can be reduced, and the mass and mass center position of the load can be accurately calibrated.
Drawings
Fig. 1 is a flowchart of a calibration method of a robot arm load according to an embodiment of the present application.
Fig. 2 to 6 are schematic structural views of the robotic arm according to the embodiments of the present application in different postures.
Fig. 7 is a block diagram of an electronic device according to an embodiment of the present application.
DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION
The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
The embodiment of the application provides a calibration method of the load at the tail end of a robot arm, which is used for calibrating the load at the tail end of the robot arm. Specifically, the calibration method of the end load of the robot arm can calibrate the mass and the mass center position of the load, wherein the mass center position comprises the offset of the mass center on each coordinate axis of a load coordinate system. The robotic arm may include various multi-joint robotic arms, such as a four-joint robotic arm, a five-joint robotic arm, a six-joint robotic arm, and the like.
Fig. 1 is a flowchart of a calibration method of an end load of an robot arm according to an embodiment of the present application, and referring to fig. 1, the calibration method of an end load of an robot arm according to an embodiment of the present application may specifically include the following steps.
S110, acquiring the target torque variation of the robot arm.
S120, determining the mass and the mass center position of the load based on the target torque variation through a moment relation model.
The target torque variation is a motor torque variation of the target joint module under the target posture before and after the robot arm is connected with the load. The target poses include a first pose, a second pose, and a third pose. And under the condition that the robot arm is in a first posture, a first coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular. And under the condition that the robot arm is in the second posture, a second coordinate axis of the load coordinate system and the motor axis of the target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular. And under the condition that the robot arm is in a third posture, a third coordinate axis of a load coordinate system and the motor axis of the target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular.
The moment relation model characterizes the association relation between the target torque variation and the heavy moment of the load. The centroid position comprises a first offset of the centroid on a first coordinate axis, a second offset of the centroid on a second coordinate axis and a third offset of the centroid on a third coordinate axis.
For example, the first coordinate axis may be an X-axis, the second coordinate axis may be a Y-axis, and the third coordinate axis may be a Z-axis. And under the first posture of the robot arm, the X axis of the load coordinate system and the motor axis of the target joint module are positioned on the same horizontal plane and are mutually perpendicular. And under the second posture of the first robot arm, the Y axis of the load coordinate system and the motor axis of the target joint module are positioned on the same horizontal plane and are mutually perpendicular. And under the third posture of the robot arm, the Z axis of the load coordinate system and the motor axis of the target joint module are positioned on the same horizontal plane and are mutually perpendicular. The first offset is the offset of the centroid on the X axis, the second offset is the offset of the centroid on the Y axis, and the third offset is the offset of the centroid on the Z axis. Of course, the correspondence between each coordinate axis and the X, Y, and Z axes described above is merely exemplary, and should not be construed as being limited to the correspondence described above.
The target joint module is any one of the joint modules of the robot arm. When the robot arm is in the first posture, the second posture and the third posture respectively, the motor torque variation of the same joint module of the robot arm can be obtained, and the motor torque variation of different joint modules of the robot arm can also be obtained respectively.
Taking the robot arm as a six-joint robot arm 20 as an example, as shown in fig. 2, the six-joint robot arm 20 may include a primary joint module 21, a secondary joint module 22, a tertiary joint module 23, a quaternary joint module 24, a penta-joint module 25 and a hexa-joint module 26 sequentially disposed from a base of the robot arm to an end of the robot arm. When the robot arm is in the first posture, the motor torque variation of the three-stage joint module 23 can be obtained. The motor torque variation of the tertiary joint module 23 can also be obtained when the robot arm is in the second posture. In the third posture of the robot arm, the motor torque variation of the five-stage joint module 25 can be obtained.
It should be noted that, none of the first posture, the second posture, and the third posture is a fixed single posture. In practice, the robot arm generally has a plurality of postures, so that the first coordinate axis of the load coordinate system and the motor axis of a certain joint module of the robot arm are in the same horizontal plane and are mutually perpendicular. The robot arm also has a plurality of postures, so that the second coordinate axis of the load coordinate system and the motor axis of one joint module of the robot arm are in the same horizontal plane and are mutually perpendicular. Similarly, the robot arm generally has a plurality of postures, so that the third coordinate axis of the load coordinate system and the motor axis of one joint module of the robot arm are in the same horizontal plane and are perpendicular to each other.
It can be appreciated that, since the target pose includes a first pose, a second pose, and a third pose, the target torque variation includes at least a motor torque variation of the target joint module when the robot arm is in the first pose, a motor torque variation of the target joint module when the robot arm is in the second pose, and a motor torque variation of the target joint module when the robot arm is in the third pose.
The target torque variation is the motor torque variation of the target joint module under the target posture before and after the robot arm is connected with the load, and one coordinate axis of the load coordinate system and the motor axis of the target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular when the robot arm is in the target posture. Before and after the robot arm is connected with a load in a target posture, the motor torque variation of the target joint module is mainly generated by the gravity moment of the load. The motor torque variation of the target joint module is equal to the weight of the load multiplied by the arm of the load.
The coordinate axis of the load coordinate system and the motor axis of the target joint module of the robot arm, which are in the same horizontal plane and are perpendicular to each other, can be defined as the target coordinate axis. On the basis, the moment arm of the load is equal to the offset of the mass center of the load on the target coordinate axis, and the sum of the vertical distance between the coordinate origin of the load coordinate system and the motor axis of the target joint module. On this basis, the correlation between the target torque variation and the gravitational moment of the load can be expressed by the following formula.
Δτ＝mg(l+Δl) (1)
Wherein Δτ represents the target torque variation; m represents the mass of the load; g represents a gravitational constant; l represents the vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the target joint module; Δl represents the first offset amount, the second offset amount, or the third offset amount. Specifically, Δl represents the first offset amount when the first coordinate axis is the target coordinate axis. When the second coordinate axis is the target coordinate axis, Δl represents the second offset amount. When the third coordinate axis is the target coordinate axis, Δl represents the third offset amount.
Optionally, under the condition that the target torque variation is obtained, the target torque variation can be imported into the moment relation model to construct a target equation set. And determining the mass, the first offset, the second offset and the third offset of the load by solving a target equation set.
Alternatively, the moment relation model may be expressed by the following formula:
wherein m represents the mass of the load; g represents a gravitational constant; Δl X Representing a first offset; Δl Y Representing a second offset; Δl Z Representing a third offset.
Δτ 1 And the first torque variation is represented and comprises the motor torque variation of the first joint module under a first posture before and after the robot arm is connected with a load. At the one part In the first posture, a first coordinate axis of the load coordinate system and the motor axis of the first joint module are positioned on the same horizontal plane and are mutually perpendicular. l (L) 1 And the first vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the first joint module is represented when the robot arm is in the first posture.
Δτ 2 And representing a second torque variation, wherein the second torque variation comprises the motor torque variation of the first joint module under the other first posture before and after the robot arm is connected with a load. In the other first posture, the first coordinate axis of the load coordinate system and the motor axis of the first joint module are located on the same horizontal plane and are perpendicular to each other. l (L) 2 And the second vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the first joint module is represented when the robot arm is in the other first posture.
Δτ 3 And representing a third torque variation, wherein the third torque variation comprises the motor torque variation of the second joint module under the first posture before and after the robot arm is connected with a load. In the first posture, the first coordinate axis of the load coordinate system and the motor axis of the second joint module are located on the same horizontal plane and are perpendicular to each other. l (L) 3 And the third vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the second joint module is represented when the robot arm is in the first posture. It is to be understood that the one first posture and the other posture are different postures, and the further one first posture may be the same as one of the one first posture and the other posture or may be different from the one first posture and the other posture.
Δτ 4 And the fourth torque variation is represented and comprises the motor torque variation of the third joint module under the second posture before and after the robot arm is connected with the load. In the second posture, the second coordinate axis of the load coordinate system and the motor axis of the third joint module are positioned on the same horizontal plane and are mutually perpendicular. l (L) 4 A motor for indicating the origin of coordinates of the load coordinate system and the third joint module in the second posture of the robot armA fourth vertical distance between the axes.
Δτ 5 And expressing a fifth torque variation, wherein the fifth torque variation comprises the motor torque variation of the fourth joint module under the third posture before and after the robot arm is connected with the load. In the third posture, the third coordinate axis of the load coordinate system and the motor axis of the fourth joint module are positioned on the same horizontal plane and are mutually perpendicular. l (L) 5 And the fifth vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the fourth joint module is shown when the robot arm is in the third posture.
On the basis, the first torque variation delta tau can be obtained 1 Second torque variation Δτ 2 Third torque variation Δτ 3 Fourth torque variation Δτ 4 And a fifth torque variation Δτ 5 . And respectively determine the first vertical distance l 1 Second vertical distance l 2 Third vertical distance l 3 Fourth vertical distance l 4 And a fifth vertical distance l 5 . Specifically, l may be determined based on the pose of the robotic arm and DH parameters 1 、l 2 、l 3 、l 4 And l 5 . For example, l 1 Is actually equal to the sum of the length of the three-level link and the length of the five-level link of the six-joint robot arm.
May be based on the first torque variation Δτ 1 The second torque variation delta tau 2 First vertical distance l 1 And a second vertical distance l 2 A mass m of the load is determined. Based on the third torque variation Δτ 3 Third vertical distance l 3 And the mass m of the load, determining the first offset Deltal X . Based on the fourth torque variation Δτ 4 Fourth vertical distance l 4 And the mass m of the load, determining the second offset Deltal Y . Based on the fifth torque variation Δτ 5 Fifth torque variation Δτ 5 And the mass m of the load, determining the third offset Deltal Z 。
Taking the robot arm as a six-joint robot arm 20 as an example, as shown in fig. 2, the six-joint robot arm 20 may include a primary joint module 21, a secondary joint module 22, a tertiary joint module 23, a quaternary joint module 24, a penta-joint module 25, and a hexa-joint module 26 sequentially disposed from a base of the six-joint robot arm 20 to an end of the six-joint robot arm 20. The end center point of the six-joint robot arm 20 may be defined as the origin O of coordinates of the load coordinate system, the X-axis of the load coordinate system may be defined as a first coordinate axis, the Y-axis of the load coordinate system may be defined as a second coordinate axis, and the Y-axis of the load coordinate system may be defined as a third coordinate axis.
On this basis, the posture when the joint angle sequence of the six-joint robot arm 20 is (0, 90,0,0,0) can be regarded as the one first posture, as shown in fig. 2. It can be seen that the X-axis of the load coordinate system and the motor axis of the three-stage joint module 23 are located in the same horizontal plane and are perpendicular to each other. The motor torque variation of the three-stage joint module 23 of the six-joint robot arm 20 may be acquired as the first torque variation. The vertical distance from the center point of the end of the six-joint robot arm 20 to the motor axis of the three-stage joint module 23 is set as the first vertical distance.
The pose of the six-joint robot arm 20 at the joint angle sequence of (0, 90, 180,0,0) may be taken as the other first pose, as shown in fig. 3. It can be seen that the X-axis of the load coordinate system and the motor axis of the three-stage joint module 23 are located in the same horizontal plane and are perpendicular to each other. The motor torque variation of the three-stage joint module 23 of the six-joint robot arm 20 may be acquired as the second torque variation. The vertical distance from the center point of the end of the six-joint robot arm 20 to the motor axis of the three-stage joint module 23 is set as the second vertical distance.
The pose of the six-joint robot arm 20 at the joint angle sequence of (0, 90,0,0,0) may be regarded as the further first pose, as shown in fig. 4. It can be seen that the X-axis of the load coordinate system and the motor axis of the three-stage joint module 23 are located in the same horizontal plane and are perpendicular to each other. The motor torque variation of the three-stage joint module 23 of the six-joint robot arm 20 may be acquired as the third torque variation. The vertical distance from the center point of the end of the six-joint robot arm 20 to the motor axis of the three-stage joint module 23 is set as the third vertical distance.
The posture at the time of the joint angle sequence of (0, 90,0,0, 90) of the six-joint robot arm 20 may be taken as the second posture, as shown in fig. 5. It can be seen that the Y-axis of the load coordinate system and the motor axes of the four-stage joint module 24 are located in the same horizontal plane and are perpendicular to each other. The motor torque variation of the four-stage joint module 24 of the six-joint robot arm 20 may be obtained as the fourth torque variation. The vertical distance from the center point of the end of the six-joint robot 20 to the motor axis of the four-stage joint module 24 is set as the fourth vertical distance.
The posture at the time of the joint angle sequence of the six-joint robot arm 20 (0, 90,0,0,0) may be regarded as the third posture, as shown in fig. 6. It can be seen that the Z-axis of the load coordinate system and the motor axis of the five-stage joint module 25 are located in the same horizontal plane and are perpendicular to each other. The motor torque variation of the five-stage joint module 25 of the six-joint robot arm 20 may be acquired as the fifth torque variation. The vertical distance between the center point of the end of the six-joint robot 20 and the motor axis of the five-stage joint module 25 is set as a fifth vertical distance.
On the basis of the obtained data, the mass of the load, the first offset amount, the second offset amount, and the third offset amount may be calculated based on formula (2).
It should be noted that, in practical application, the moment relation model is not limited to be represented by the formula (1) and the formula (2), and the adaptive change can be performed according to the structural change of the robot arm and the selection of the target gesture, so long as the association relation between the target torque variation and the heavy moment of the load can be represented.
It is to be noted that, as is apparent from the above-described joint angle sequence, the same posture is actually illustrated in fig. 2, 4 and 6, and the first torque variation and the third torque variation are actually the same torque variation. In practical application, the target torque variation is not limited to include four sets of motor torque variation, as long as the moment relation model can be satisfied to calculate the mass, the first offset, the second offset and the third offset of the load.
According to the calibration method of the robot arm load, the target torque variation of the target robot arm is obtained, and the mass centroid position of the load can be determined based on the target torque variation through the moment relation model. Therefore, the motion process of the robot arm can be simplified, the data processing capacity can be reduced, and the mass and mass center position of the load can be accurately calibrated.
In some embodiments, step S110, obtaining the target torque variation of the robotic arm may include the following steps.
S111, acquiring motor load torque of the target joint module when the robot arm connected with the load is in the target posture.
S112, acquiring the motor idle torque of the target joint module when the robot arm with no load connected is in the target posture.
S113 of determining the target torque variation amount based on the motor load torque and the motor no-load torque.
Alternatively, the target torque variation amount may be calculated by the following formula on the basis of the motor load torque and the motor no-load torque of the target joint module.
Δτ＝τ Load(s) -τ No-load (3)
Wherein Δτ represents the target torque variation; τ Load(s) Representing motor load torque; τ No-load Indicating the motor no-load torque. After the motor load torque and the motor no-load torque are obtained, the motor load torque can be used for subtracting the motor no-load torque, and then the target torque variation can be obtained.
In some embodiments, step S111, obtaining the motor load torque of the target joint module when the robot arm to which the load is connected is in the target pose may include the following steps.
S1111, controlling a target joint module of the robot arm connected with the load to independently rotate through a target posture, and determining a motor load current of the target joint module when the robot arm is in the target posture.
S1112, determining the motor load torque of the target joint module based on the motor load current.
The motor load current and the motor load torque generally have positive correlation, and the motor load torque of the target joint module can be accurately calculated by detecting the motor load current. Of course, in practical application, the motor load torque may be determined by other methods, not limited to the method of detecting the motor current.
In some embodiments, step S1111, controlling the target joint module of the robot arm to which the load is connected to individually rotate through the target pose and determining the motor load current of the target joint module when the robot arm is in the target pose may include the following steps.
And controlling the target joint module connected with the loaded robot arm to independently rotate at a uniform speed along the clockwise direction to pass through the target gesture, and acquiring the forward load current of the motor of the target joint module when the robot arm is in the target gesture.
And controlling the target joint module connected with the loaded robot arm to independently rotate at a constant speed along the anticlockwise direction to pass through the target gesture, and acquiring negative load current of a motor of the target joint module when the robot arm is in the target gesture.
The motor load current is determined based on an average of the motor positive load current and the motor negative load current.
The kinetic model of the joint module of the robot arm can be expressed by the following formula.
Wherein τ mo A motor torque representing the joint module; θ represents the joint angle sequence of the robotic arm;the rotating speed of the joint module is represented; />Indicating the acceleration of the joint module; m (θ) moment of inertia; />Representing coriolis force and centrifugal torque; g (θ) represents a gravitational moment; />Representing the friction torque.
As can be seen from the formula (4), the motor torque is not only affected by the gravity moment but also overcomes the inertia moment, the coriolis force, the centrifugal moment and the friction moment during practical application. In order to avoid the influence of inertia moment, coriolis force, centrifugal moment and friction moment on the calibration result of the load, a section of constant-speed track can be designed, the influence of the inertia moment, the coriolis force and the centrifugal moment can be effectively eliminated through single joint positive and negative rotation, the load current of the motor can be obtained by averaging the positive load current and the negative load current, the influence of the friction moment can be eliminated, and the accurate calibration of the calibration result can be improved.
Optionally, the target joint module of the robot arm connected with the load can be controlled to rotate at a constant speed along a clockwise direction, when the target joint module rotates to a target range, first current data of a motor of the target joint module is obtained, and the forward load current is determined based on the first current data. And the target joint module of the robot arm connected with the load can be controlled to independently rotate at a constant speed along the anticlockwise direction, when the target joint module rotates to a target range, second current data of a motor of the target joint module is obtained, and the negative load current is determined based on the second current data. When the target joint module rotates to a target joint angle, the robot arm is in a target posture, and the target joint angle is a middle value of the target range.
Optionally, an angle range of plus or minus 1 ° of the target joint angle may be used as the target range, and a current value of the target joint angle sequence rotated to the range of plus or minus 1 ° of the target joint angle may be collected as the first current data and the second current data, respectively. The first current data and the second current data each include a set of current values. The average value of the first current data can be used as the positive load current, the average value of the second current data can be used as the negative load current, and the motor load current can be obtained by calculating the average value of the positive load current and the negative load current. Therefore, the influence of current on the torque can be eliminated, the influence of friction torque on the motor torque can be eliminated more accurately, and the accuracy of the calibration result can be further improved.
Obviously, in practical application, not only the angle range of plus or minus 1 ° of the target joint angle but also the angle range of plus or minus 1.5 °, 2 ° or 2.5 ° of the target joint angle may be used as the target range.
Still taking the six-joint robot arm 20 as an example, the three-stage joint module 23 of the six-joint robot arm 20 can be controlled to rotate from the (0, 86,0,0,0) joint angle sequence to the (0, 94,0,0,0) joint angle sequence at a constant speed, then rotate from the (0, 94,0,0,0) joint angle sequence to the (0, 86,0,0,0) joint angle sequence, and collect current data of 1 degree near (0, 90,0,0,0) in the tracks at two ends. Based on the two sets of current data, positive load current and negative load current are calculated respectively, and based on the average value of the positive load current and the negative load current, the motor load motor is determined, and then the motor load torque of the three-stage joint module 23 is determined. The first torque variation and the third torque variation can be determined based on the motor load torque and the motor no-load torque.
The three-stage joint module 23 of the six-joint robot arm 20 can be controlled to rotate from the (0, 86, 180,0,0) joint angle sequence to the (0, 94, 180,0,0) joint angle sequence at a constant speed, then rotate from the (0, 94, 180,0,0) joint angle sequence to the (0, 86, 180,0,0) joint angle sequence, collect current data of 1 degree near (0, 90, 180,0,0) in the tracks at two ends, and further determine the second torque variation.
The four-stage joint module 24 of the six-joint robot arm 20 can be controlled to rotate from the (0, 90, -4,0, 90) joint angle sequence to the (0, 90,4,0, 90) joint angle sequence at a constant speed, then rotate from the (0, 90,4,0, 90) joint angle sequence to the (0, 90, -4,0, 90) joint angle sequence, collect current data of 1 degree near (0, 90,0,0, 90) in the tracks at two ends, and further determine the fourth torque variation.
The five-stage joint module 25 of the six-joint robot arm 20 can be controlled to rotate from the (0, 90,0, -4, 0) joint angle sequence to the (0, 90,0,4,0) joint angle sequence at a constant speed, then rotate from the (0, 90,0,4,0) joint angle sequence to the (0, 90,0, -4, 0) joint angle sequence, collect current data of 1 degree near (0, 90,0,0,0) in the tracks at two ends, and further determine a fifth torque variation.
In some embodiments, step S1112, obtaining the motor idle torque of the target joint module when the robot arm to which the load is not connected is in the target pose, may include the following steps.
And determining the motor idle torque of the target joint module when the robot arm with the unconnected load is in the target posture through a dynamic model.
Therefore, the process that the robot arm moves to each target gesture under the idle state can be omitted, the calibration process is simplified, and the calibration efficiency is improved.
Taking the six-joint robot arm 20 as an example, the motor idle torque of the corresponding target joint module may be calculated based on (0, 90,0,0,0), (0, 90, 180,0,0), (0, 90,0,0, 90), and (0, 90,0,0,0) using equation (4), so as to determine the first torque variation, the second torque variation, the third torque variation, the fourth torque variation, and the fifth torque variation.
Of course, if the motor is under load, the robot arm which is not connected with the load is controlled to move to each target gesture respectively, and the motor current of the target joint module is collected, so that the motor no-load torque of the target joint module is determined.
It should be further noted that, although the above examples take six-joint robot arms as examples to describe the steps and principles of the present application, it should not be understood that the calibration method of the end load of the robot arm is only applicable to six-joint robot arms, and the calibration method of the end load of the robot arm in the embodiments of the present application is also applicable to multi-joint robot arms such as three-joint robot arms, four-joint robot arms, and five-joint robot arms.
Referring to fig. 7, an embodiment of the present application further provides an electronic device, which at least includes a memory 301 and a processor 302, where the memory 301 stores a program, and the processor 302 implements the method described in any of the embodiments above when executing the program on the memory 301.
Embodiments of the present application also provide a computer-readable storage medium having stored therein computer-executable instructions that when executed implement a method as in any of the embodiments above.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, an electronic device, a computer-readable storage medium, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media having computer-usable program code embodied therein. When implemented in software, these functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium.
The processor may be a general purpose processor, a digital signal processor, an application-specific integrated circuit (ASIC), a programmable logic device (programmable logic device, PLD), or a combination thereof. The PLD may be a complex programmable logic device (complex programmable logic device, CPLD), a field-programmable gate array (field-programmable gate array, FPGA), general-purpose array logic (generic array logic, GAL) or any combination thereof. The general purpose processor may be a microprocessor or any conventional processor or the like.
The memory may include volatile memory in a computer-readable medium, random Access Memory (RAM) and/or nonvolatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium.
The readable storage medium may be a magnetic disk, an optical disk, a DVD, a USB, a read-only memory (ROM), a random-access memory (RAM), etc., and the specific storage medium form is not limited in this application.
The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application, the scope of which is defined by the claims. Various modifications and equivalent arrangements may be made to the present application by those skilled in the art, which modifications and equivalents are also considered to be within the scope of the present application.

Claims (10)

1. A method for calibrating an end load of a robotic arm, comprising:
acquiring a target torque variation of the robot arm;
determining the mass and centroid position of the load based on the target torque variation through a moment relation model;
the target torque variation is the motor torque variation of the target joint module under the target posture before and after the robot arm is connected with the load; the target joint module is any one of the joint modules of the robot arm;
the target gesture comprises a first gesture, a second gesture and a third gesture; when the robot arm is in a first posture, a first coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular; when the robot arm is in a second posture, a second coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are in the same horizontal plane and are mutually perpendicular; in a third posture of the robot arm, a third coordinate axis of a load coordinate system and a motor axis of a target joint module of the robot arm are positioned on the same horizontal plane and are mutually perpendicular;
the moment relation model characterizes the association relation between the target torque variation and the heavy moment of the load; the centroid position comprises a first offset of the centroid on a first coordinate axis, a second offset of the centroid on a second coordinate axis and a third offset of the centroid on a third coordinate axis.
2. The method of claim 1, wherein obtaining a target torque variation for the robotic arm comprises:
acquiring motor load torque of a target joint module when a robot arm connected with a load is in a target posture;
acquiring a motor no-load torque of a target joint module when the robot arm with no load is in a target attitude;
the target torque variation amount is determined based on the motor load torque and the motor no-load torque.
3. The method of claim 2, wherein obtaining the motor load torque of the target joint module with the load-connected robotic arm in the target pose comprises:
controlling a target joint module of a robot arm connected with a load to independently rotate through a target gesture, and determining the motor load current of the target joint module when the robot arm is in the target gesture;
and determining the motor load torque of the target joint module based on the motor load current.
4. A method according to claim 3, wherein controlling the target joint modules of the robot arm to which the load is connected to individually rotate through the target pose and determining the motor load current of the target joint modules when the robot arm is in the target pose comprises:
The method comprises the steps of controlling a target joint module connected with a loaded robot arm to independently rotate at a uniform speed along a clockwise direction to pass through a target gesture, and obtaining forward load current of a motor of the target joint module when the robot arm is in the target gesture;
the method comprises the steps of controlling a target joint module connected with a loaded robot arm to independently rotate at a constant speed along a counterclockwise direction to pass through a target gesture, and obtaining negative load current of a motor of the target joint module when the robot arm is in the target gesture;
the motor load current is determined based on an average of the motor positive load current and the motor negative load current.
5. The method of claim 4, wherein controlling the target joint module of the robot arm to which the load is connected to individually rotate clockwise through the target pose at a constant speed and obtain the motor forward load current of the target joint module when the robot arm is in the target pose comprises:
the method comprises the steps of controlling a target joint module of a robot arm connected with a load to independently rotate at a uniform speed in a clockwise direction, acquiring first current data of a motor of the target joint module when the target joint module rotates to a target range, and determining the forward load current based on the first current data;
Correspondingly, controlling the target joint module connected with the loaded robot arm to independently rotate at a constant speed along the anticlockwise direction to pass through the target gesture, and acquiring the negative load current of the motor of the target joint module when the robot arm is in the target gesture, comprising:
the method comprises the steps of controlling a target joint module of a robot arm connected with a load to independently rotate at a constant speed along a counterclockwise direction, acquiring second current data of a motor of the target joint module when the target joint module rotates to a target range, and determining the negative load current based on the second current data;
when the target joint module rotates to a target joint angle, the robot arm is in a target posture, and the target joint angle is a middle value of the target range.
6. The method of claim 2, wherein obtaining the motor no-load torque of the target joint module with the non-load connected robotic arm in the target pose comprises:
and determining the motor idle torque of the target joint module when the robot arm with the unconnected load is in the target posture through a dynamic model.
7. The method of claim 2, wherein obtaining a target torque variation for the robotic arm comprises:
Acquiring a first torque variation, a second torque variation, a third torque variation, a fourth torque variation and a fifth torque variation;
the first torque variation comprises motor torque variation of the first joint module under a first posture before and after the robot arm is connected with a load; the second torque variation comprises motor torque variation of the first joint module under the other first posture before and after the robot arm is connected with a load; under the first gesture and the second gesture, the gesture of the end load of the robot arm is different, and the first coordinate axis of the load coordinate system and the motor axis of the first joint module are positioned on the same horizontal plane and are mutually perpendicular;
the third torque variation comprises motor torque variation of the second joint module under a first posture before and after the robot arm is connected with a load, and in the first posture, a first coordinate axis of a load coordinate system and a motor axis of the second joint module are positioned on the same horizontal plane and are mutually perpendicular;
the fourth torque variation comprises motor torque variation of the third joint module under the second posture before and after the robot arm is connected with the load; in the second posture, the second coordinate axis of the load coordinate system and the motor axis of the third joint module are positioned on the same horizontal plane and are mutually perpendicular;
The fifth torque variation comprises motor torque variation of the fourth joint module in a third posture before and after the robot arm is connected with the load, and in the third posture, a third coordinate axis of the load coordinate system and a motor axis of the fourth joint module are positioned on the same horizontal plane and are mutually perpendicular.
8. The method of claim 7, wherein determining the mass and centroid location of the load based on the target torque variation through a moment relation model comprises:
determining a mass of the load based on the first torque variation and the second torque variation through the torque relationship model;
determining the first offset based on the third torque variation and the mass of the load by the torque relationship model;
determining the second offset based on the fourth torque variation and the mass of the load by the torque relationship model;
and determining the third offset based on the fifth torque variation and the mass of the load through the torque shutdown model.
9. The method of claim 1, wherein the moment relation model is represented by the formula:
Δτ＝mg(l+Δl)
wherein Δτ represents the target torque variation; m represents the mass of the load; g represents a gravitational constant; l represents the vertical distance between the origin of coordinates of the load coordinate system and the motor axis of the target joint module; Δl represents the first offset amount, the second offset amount, or the third offset amount.
10. An electronic device comprising at least a memory and a processor, the memory having a program stored thereon, characterized in that the processor, when executing the program on the memory, implements the method of any of claims 1-9.
CN202311760706.3A 2023-12-19 2023-12-19 Calibration method of end load of robot arm and electronic equipment Pending CN117532618A (en)

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