Industrial robot virtual debugging and simulation method based on digital twinning

Abstract

The invention provides an industrial robot virtual debugging and simulation method based on digital twinning. The method comprises the following steps: S1, establishing a digital twinning model of an industrial robot; s2, establishing a kinematics model of the industrial robot, and performing forward kinematics analysis and inverse kinematics analysis on the established kinematics model; s3, associating the digital twin model established in the step S1 with an industrial robot signal, and performing virtual debugging and digital twin virtual-real mapping; and S4, realizing digital twinborn visualization by the industrial robot, namely establishing a digital twinborn model highly consistent with the actual robot and the working environment thereof in the virtual environment, and establishing real-time communication between the digital twinborn model and the actual robot, thereby realizing comprehensive debugging on the actual robot and peripheral equipment thereof in the virtual environment. Meanwhile, the state of the actual robot is mapped into the digital twinborn model, comprehensive simulation of the actual robot and the running state of the actual robot is achieved, and the simulation precision and adaptability of the industrial robot are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial robot commissioning and simulation, and particularly to a virtual commissioning and simulation method for industrial robots based on digital twin. Background Art

[0002] The integration of new-generation information technology and manufacturing industry has made intelligent automation one of the mainstream trends in the current manufacturing industry. Industrial robots are more cost-effective in terms of flexibility, repeatability, and support for new functions, and can effectively improve production efficiency and product quality. Industrial robots have become a symbol of automation and intelligence in the manufacturing industry.

[0003] Currently, there are two programming modes for robot programming: online mode and offline mode. Online programming occupies the actual working time of the robot and requires manual teaching by staff, resulting in low overall efficiency and poor accuracy. Therefore, the online programming method is no longer applicable to the current manufacturing industry. The offline programming method constructs a three-dimensional model of the robot and its working scenario in a virtual environment, establishes a simulation environment and generates a program in offline simulation, and transfers it to the physical system. The offline programming method separates the real robot system environment from the programming environment, avoiding potential safety hazards in some dangerous scenarios; compared with the online programming method, the offline programming method does not occupy production resources and also saves labor costs.

[0004] However, due to the independence of information between the real space and the virtual space, the relevant information of the actual robot cannot be real-time fed back to the virtual simulation system. Similarly, if the relevant data of the robot is modified in the virtual environment, it cannot be quickly synchronized to the actual scenario. Moreover, if the production line changes, the cost of re-planning the work process is relatively high. Summary of the Invention

[0005] A virtual commissioning and simulation method for industrial robots based on digital twin disclosed by the present invention solves the problem that the information between the real space and the virtual space is independent during offline programming, resulting in the relevant information of the actual robot not being able to be real-time fed back to the virtual simulation system; and the relevant data of the robot modified in the virtual space cannot be quickly synchronized to the actual robot. A digital twin model that is highly consistent with the actual robot and its working environment is established in the virtual environment, and real-time communication is established between the two, so as to realize comprehensive commissioning of the actual robot and its peripheral equipment in the virtual environment, and at the same time map the state of the actual robot to the digital twin model, realizing comprehensive simulation of the actual robot and its operating state, effectively improving the accuracy and adaptability of industrial robot simulation.

[0006] To achieve the above object, the technical solution of the present invention is specifically implemented as follows:

[0007] The present invention discloses a virtual commissioning and simulation method for industrial robots based on digital twin, including the following

[0008] steps:

[0009] S1: Establish a digital twin model of the industrial robot;

[0010] S2: Establish a kinematic model of the industrial robot, and perform forward kinematic analysis and inverse kinematic analysis on the established kinematic model;

[0011] S3: Associate the digital twin model of the industrial robot established in step S1 with the industrial robot signals, and perform virtual commissioning and digital twin virtual-real mapping;

[0012] S4: Realize digital twin visualization of the industrial robot.

[0013] Furthermore, the specific implementation of step S1 is as follows:

[0014] Directly select and import according to the model of the industrial robot or establish a model according to the actual geometric dimensions of the industrial robot;

[0015] Set the same material, color, shape and structural relationship as the industrial robot for the geometric model, so that the generated digital twin model has a visual and structural twin relationship with the industrial robot.

[0016] Furthermore, the specific implementation of the forward kinematic analysis in step S2 is as follows:

[0017] The forward kinematic analysis is to determine the pose of the end effector when the joint angles, link lengths and combination methods of the robot are determined. The pose of the end effector is represented by a homogeneous transformation matrix and the specific expression is:

[0018]

[0019] where represents the pose of the 6 joint coordinate systems relative to the base coordinate system; represents the relative relationship between the i-th joint and the (i-1)-th joint coordinate system; (n x ,n y ,n z ) represents the x-axis direction of the end effector coordinate system; (o x ,o y ,o z ) represents the y-axis direction of the end effector coordinate system; (a x ,a y ,a z ) represents the z-axis direction of the end effector coordinate system; (p x ,p y ,pz ) represents the position of the end effector;

[0020] Using the link length a i , the link twist angle α i , the link offset d i , and the joint rotation angle θ i Four parameters to describe the relative relationship between two adjacent links. Specifically: d i is the distance measured along the Z i-1 axis from the origin of the (i - 1)-th coordinate system to the intersection of the Z i axis and the X i-1 axis; a i is the length of the common normal of the axis of joint i and the axis of joint i + 1; α i is the angle between the axis of joint i and the axis of joint i + 1 in the plane formed by the axis of joint i and a i ; θ i is the joint angle of rotation about the Z i-1 axis from the X i-1 axis to the X i axis, where i = 1, 2,..., 6; the initial values represent the angles of each joint in the initial state of the industrial robot;

[0021] The transformation relationship is represented by the matrix as follows:

[0022]

[0023] Among them, Trans(X, l) represents a translation transformation, that is, a translation of l units in the positive X-axis direction; Rot(X, θ) represents a rotation transformation, that is, a rotation of θ angles in the positive X-axis direction;

[0024] Combining Equation (1) and Equation (2) to obtain the pose matrix of the end effector at the key point

[0025] Furthermore, the inverse kinematic analysis in step S2 is specifically implemented as follows:

[0026] Inverse kinematics refers to solving for each joint angle θ in reverse through the pose matrix of the end effector i (i = 1, 2,..., 6);

[0027] Separate the expressions for the position and orientation of the industrial robot. Specifically:

[0028] Multiply the transformation matrices of the first three joint coordinate systems in Equation (1) to the left side of the equation:

[0029]

[0030] Taking the equality of the matrices on both sides of equation (3) in a block - by - block manner, the following system of equations is obtained:

[0031]

[0032] where s i =sinθ i , c i =cosθ i , s ij =sin(θ i +θ j ), c ij =cos(θ i +θ j )(i = 1, 2, …, 6)(j = 1, 2, …, 6);

[0033] Introduce the arctan2(y / x) function to solve for θ in equation (4), obtaining all 8 sets of solutions for the six joint angles:

[0034] Since the equalities in equation (4) can all be represented by the following formula:

[0035] asinθ i +bcosθ i =c (5)

[0036] If a, b, c are continuous in this formula, and the equation has solutions only when the inequality a 2 +b 2 >c 2 holds:

[0037]

[0038] Combining equations (4), (5), and (6), all 8 sets of solutions are obtained.

[0039] Furthermore, the principle for obtaining the optimal solution among the 8 sets of solutions obtained is:

[0040]

[0041] where θ ij represents the j - th set of solutions for the i - th joint, and θ i ′ represents the angle of the i - th joint at the previous position.

[0042] Furthermore, the specific implementation of step S3 includes:

[0043] Using the process simulation method, endow the digital twin model with process attributes, so that each process action of the industrial robot digital twin model has corresponding motion process logic;

[0044] Use a timing editor to perform timing simulation on the process attributes of an industrial robot, and plan the timing relationship of each process according to the timing table of the action process;

[0045] Realize the synchronous mapping between the industrial robot and its digital twin model:

[0046] Establish real-time communication between the industrial robot and its digital twin model;

[0047] When the control unit of the industrial robot is a communication server, realize virtual reality: the industrial robot transmits its joint data to its digital twin model in real time, and the digital twin model receives the joint data transmitted by the industrial robot and applies steps S1 and S2 to achieve synchronous movement;

[0048] When the control unit of the digital twin model is a communication server, realize virtual control of reality: the digital twin model sends control instructions to the control unit of the industrial robot, and the industrial robot receives and executes the control instructions.

[0049] Furthermore, the timing simulation of the industrial robot is time-based simulation.

[0050] Beneficial technical effects:

[0051] The present invention discloses a virtual commissioning and simulation method for an industrial robot based on digital twin, which specifically includes the following steps: S1: Establish a digital twin model of the industrial robot; S2: Establish a kinematic model of the industrial robot, and perform forward kinematic analysis and inverse kinematic analysis on the established kinematic model; S3: Associate the digital twin model of the industrial robot established in step S1 with the industrial robot signal, and perform virtual commissioning and digital twin virtual-real mapping; S4: The industrial robot realizes digital twin visualization, that is, a digital twin model highly consistent with the actual robot and its working environment is established in a virtual environment, and real-time communication is established between the two, so as to realize comprehensive commissioning of the actual robot and its peripheral equipment in the virtual environment, and at the same time map the state of the actual robot to the digital twin model, realizing a comprehensive simulation of the actual robot and its operating state, effectively improving the accuracy and adaptability of industrial robot simulation. Description of the Drawings

[0052] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for description in the embodiments will be briefly introduced below.

[0053] Figure 1 It is a specific step flowchart of a virtual commissioning and simulation method for an industrial robot based on digital twin according to the present invention;

[0054] Figure 2 It is a spatial structure diagram of a six-degree-of-freedom industrial robot;

[0055] Figure 3 This is the relationship diagram of the link joint axes of the industrial robot in the embodiment of the present invention;

[0056] Figure 4 This is the software cross-sectional view of the Home point setting of the industrial robot in the embodiment of the present invention;

[0057] Figure 5 This is the action process timing chart of the industrial robot in the embodiment of the present invention;

[0058] Figure 6 This is the signal connection flow chart of the industrial robot in the embodiment of the present invention. Detailed implementation manners

[0059] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0060] The embodiments of the present invention will be described in detail below in conjunction with the drawings.

[0061] It should be noted that the working environment composed of the components, control units, and systems related to the digital twin model in the present invention is a virtual environment.

[0062] The present invention discloses a method for running a distributed data acquisition system. Refer to Figure 1 , which specifically includes the following steps:

[0063] S1: Establish a digital twin model of the industrial robot;

[0064] Specifically, there are usually two ways to perform geometric modeling of the digital twin model of the industrial robot, that is, directly select and import according to the model of the industrial robot or establish a model (including the workpiece and production line model) according to the actual geometric dimensions of the industrial robot, and then endow the digital twin model with the same material as the actual industrial robot to ensure that the digital twin model is highly consistent with the actual industrial robot in terms of geometric dimensions, material properties, color, shape, etc., having a visual "twin", and at the same time can truly reflect the assembly relationship, origin position, subordinate relationship, etc. of the actual working environment of the industrial robot, having a structural "twin".

[0065] S2: Establish a kinematic model of the industrial robot, and perform forward kinematic analysis and inverse kinematic analysis on the established kinematic model;

[0066] Specifically, the industrial robot model should have the ability of motion simulation, that is, the translational or rotational changes between the connecting rods (depending on the type of the robot joint axis). Then, parameters such as the positive direction of the connecting rod movement, the selection rule of the reference coordinate system, and its offset in the virtual environment are consistent with the actual situation. The trajectory planning process of the robot should satisfy the kinematic constraints, which are manifested as the angle and speed interpolation in the joint space or the pose interpolation of the end effector in the Cartesian space.

[0067] To determine the angles of each joint when the end effector is in the key pose, the kinematic expression of the robot is analyzed, including the kinematic modeling process, the forward kinematics solution, and the inverse kinematics solution process. The forward kinematics solution is to calculate the homogeneous transformation matrix of the end effector coordinate system relative to the base coordinate system through the combination relationship (rotation angle) of each joint and connecting rod, so as to grasp the running state of the robot in real time; while the inverse kinematics solution is the process of converting the position points in the Cartesian space into the angles in the joint space; since the robot often needs to plan the path according to the pose in the Cartesian coordinate system when performing tasks in the industrial field, the inverse kinematics solution occupies an important position in the trajectory planning process.

[0068] It should be noted that in this embodiment, a six-degree-of-freedom industrial robot is taken as an example. Refer to Figure 2 to specifically describe the method disclosed in the present invention.

[0069] The inverse kinematics solution methods of six-axis robots mainly include numerical methods and analytical methods. Among them, the numerical method needs to be realized through iterative calculation. Since the calculation amount is large, the solution speed is usually slower than that of the analytical method. For a six-axis serial robot, as long as the Pieper criterion is satisfied, there is an analytical solution that meets the conditions. The classical D-H parameter method is used to establish the forward kinematics model of the robot and the inverse kinematics solution process.

[0070] The specific solution is as follows:

[0071] The forward kinematics analysis is specifically realized as:

[0072] The forward kinematics analysis is to determine the pose of the end effector when the joint angles, connecting rod lengths, and combination methods of the robot are determined. The pose of the end effector is represented by the homogeneous transformation matrix and the specific expression is:

[0073]

[0074] Among them, represents the pose of the 6 joint coordinate systems relative to the base coordinate system; represents the relative relationship between the i-th joint and the (i - 1)-th joint coordinate system; (n x ,n y ,n z) represents the x-axis direction of the end effector coordinate system; (o x ,o y ,o z ) represents the y-axis direction of the end effector coordinate system; (a x ,a y ,a z ) represents the z-axis direction of the end effector coordinate system; n, o, a are three orthogonal unit vectors describing the attitude of the end effector, and these three vectors together form the rotation matrix part of the end effector; (p x ,p y ,p z ) represents the position of the end effector;

[0075] Using the link length a i , the link twist angle α i , the link offset d i , and the joint rotation angle θ i Four parameters to describe the relative relationship between two adjacent links, see Figure 3 , specifically: d i is the distance measured along the Z i-1 axis from the origin of the (i - 1)-th coordinate system to the intersection of the Z i axis and the X i-1 axis; a i is the length of the common normal of the axis of joint i and the axis of joint i + 1; α i is the angle between the axis of joint i and the axis of joint i + 1 in the plane formed by the axis of joint i and a i ; θ i is the joint angle of rotation around the Z i-1 axis from the X i-1 axis to the X i axis, where i = 1, 2,..., 6; the initial values represent the angles of each joint in the initial state of the industrial robot;

[0076] The transformation relationship is represented by the matrix as follows:

[0077]

[0078] Among them, Trans(X, l) represents a translation transformation, that is, a translation of l units along the positive X-axis direction; Rot(X, θ) represents a rotation transformation, that is, a rotation of θ angles around the positive X-axis direction;

[0079] Combining Equation (1) and Equation (2) to obtain the pose matrix of the end effector at the key point

[0080] The specific implementation of inverse kinematics analysis is:

[0081] Inverse kinematics refers to obtaining through the pose matrix of the end effector Inverse solution of each joint angle θ i (i = 1, 2, …, 6);

[0082] Separate the expressions of the position and attitude of the industrial robot. Specifically:

[0083] Multiply the left side of the equation by the transformation matrices of the first three joint coordinate systems in Equation (1):

[0084]

[0085] Perform blockwise equality on the matrices on both sides of Equation (3) to obtain a system of equations:

[0086]

[0087] where s i = sinθ i , c i = cosθ i , s ij = sin(θ i + θ j ) c ij = cos(θ i + θ j )(i = 1, 2, …, 6)(j = 1, 2, …, 6);

[0088] Introduce the arctan2(y / x) function to solve θ in Equation (4) and obtain all 8 sets of solutions for the six joint angles:

[0089] Since the equalities in Equation (4) can all be expressed by the following formula:

[0090] asinθ i + bcosθ i = c (5)

[0091] If a, b, and c are continuous in this formula, and only when the inequality a 2 + b 2 > c 2 holds, the equation has a solution:

[0092]

[0093] Combine Equations (4), (5), and (6) to obtain all 8 sets of solutions.

[0094] Since the deviation of the first three joint angles has a greater impact on the end effector, it is necessary to ensure that the difference between the current angles of the first three joint angles and the angles at the previous key point is minimized. The least squares method is used to select a set of solutions that meet the conditions as the optimal solution to achieve the purpose of saving operation time and energy. All key point poses can be converted into the angles of each joint through the above method.

[0095] The principle for obtaining the optimal solution among the 8 sets of solutions obtained is:

[0096]

[0097] Among them, θ ij represents the j-th set of solutions of the i-th joint, and θ i ' represents the angle of the i-th joint at the previous point.

[0098] S3: Associate the digital twin model of the industrial robot established in step S1 with the industrial robot signal for virtual commissioning and digital twin virtual-real mapping;

[0099] Specifically, it includes:

[0100] S31: Using the process simulation method, endow the digital twin model with process attributes so that each process action of the industrial robot digital twin model has corresponding motion process logic;

[0101] Specifically, using the process simulation method, endow the industrial robot with process attributes, such as the opening and closing of the fixture when the industrial robot grasps parts and the path of clamping, as well as the angle and angular velocity when the turntable rotates, so that each process action of the industrial robot has corresponding motion process logic.

[0102] From the inverse kinematics of the robot, the mapping from the end position of the robot to the joint position is very complex. Especially for robots with multiple degrees of freedom, there may sometimes be no analytical solution. Therefore, to prevent the generation of singular solutions, when defining the robot process, appropriate transition points can be added.

[0103] For example, taking Figure 4 as an example, set the following points during the movement process of the industrial robot:

[0104] The Home point is defined to prevent the robot from encountering singularities during movement. To change the initial posture of the robot, the new posture is the Home point of the robot; Transition point 1: A transition point is established between the Home point of the industrial robot and the robot's grasping position point to prevent the robot from encountering collision points or limit points during movement; Here, the robot is rotated 60° along the Z-axis; Transition point 2: Generally set directly above the grasping point, this point is to align with the workpiece grasping position point; Grasping point: This point is where the robot grasps the workpiece; Via_5 point: This point is where the robot prevents collision with the machining center.

[0105] Therefore, the process setting of the industrial robot is to move from the "Home point" to the "Transition point 1", then to the "Transition point 2", and finally to the "Grasping point"; After the workpiece is grasped, it moves from the "Grasping point" to the "Transition point 2", then to the "Transition point 1", and finally to the "Home point", ensuring the smooth path of the robot through the process.

[0106] S32: Use the timing editor to perform timing simulation on the process attributes of the industrial robot, and plan the timing relationship of each process according to the timing table of the action process;

[0107] Specifically, after the process attributes of the robot are defined, use the timing editor to perform timing simulation. Plan the timing relationship of each process according to the timing table of the action process, and verify the rationality of the production process through process timing simulation. Preferably, the process timing simulation is a time-based simulation, see Figure 5 。

[0108] S33: Realize the synchronous mapping between the industrial robot and its digital twin model:

[0109] Establish real-time communication between the industrial robot and its digital twin model;

[0110] Specifically, the communication between the industrial robot and the virtual environment uses the TCP / IP protocol, and uses the network programming interface Socket to transmit the real-time joint data of the robot. Applying Steps 1 and 2 in the virtual model can realize the synchronous movement of the digital twin model, and bind the virtual digital twin model to the real data;

[0111] When the control unit of the industrial robot is the communication server, realize virtual-to-real mapping: The industrial robot transmits its joint data to its digital twin model in real time, and its digital twin model receives the joint data transmitted by the industrial robot and applies Steps S1 and S2 to realize synchronous movement;

[0112] When the control unit of the digital twin model is the communication server, realize virtual control of the real: The digital twin model sends control instructions to the control unit of the industrial robot, and the industrial robot receives and executes the control instructions;

[0113] Preferably, the real-time data collection is divided into two categories: real-time position data and real-time signal data. The real-time position data includes, but is not limited to, the real-time joint angles, joint speeds, end poses, etc. during the movement of the industrial robot; the real-time signal data includes, but is not limited to, PLC signals, etc.; the signal configuration mainly includes signal name, type, address, serial number, controlled model ID, IEC format, etc.; the signal connection process is mainly divided into creating a new signal, signal parameter configuration, signal type definition, setting model resources, setting signal address, logical linkage, and digital twin. See Figure 6 .

[0114] S4: The industrial robot realizes digital twin visualization.

[0115] Specifically, after the kinematic definition, process simulation, machining timing simulation, and data signal connection of the industrial robot model, through the digital twin scene publishing, the scene with behavioral logic attributes and capable of being driven by actual real-time data signals is published as a digital twin scene, realizing the digital twin effect of real-time dynamic mapping of the action state of the industrial robot.

[0116] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0117] The above embodiments are only descriptions of the preferred implementation manners of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A virtual debugging and simulation method for industrial robots based on digital twins, characterized in that: The following steps are involved: S1: Establish a digital twin model of industrial robots; S2: Establish a kinematic model of the industrial robot and perform forward kinematics analysis and inverse kinematics analysis on the established kinematic model; S3: Associating the digital twin model of the industrial robot established in step S1 with the industrial robot signal to perform virtual debugging and digital twin virtual-real mapping; S4: Industrial robots realize digital twin visualization.

2. The method for virtual debugging and simulation of an industrial robot based on digital twin according to claim 1, characterized in that: The specific implementation of step S1 is: Directly import the industrial robot model or build the model based on the actual geometric dimensions of the industrial robot; The geometric model is set to have the same material, color, shape and structural relationship as the industrial robot, so that the generated digital twin model has a visual and structural twin relationship with the industrial robot.

3. The method for virtual debugging and simulation of an industrial robot based on digital twin according to claim 1, characterized in that: The forward kinematics analysis in step S2 is specifically implemented as follows: Forward kinematics analysis is to determine the position and posture of the end effector when the joint angle, link length and combination of the robot are determined. The position and posture of the end effector is determined by the homogeneous transformation matrix The specific expression is: in, Represents the position and posture of the 6 joint coordinate systems relative to the base coordinate system; Represents the relative relationship between the i-th joint and the i-1 joint coordinate system; (n x ,n y ,n z ) represents the x-axis direction of the end effector coordinate system; (o x ,o y ,o z ) represents the y-axis direction of the end effector coordinate system; (a x ,a y ,a z ) represents the z-axis direction of the end effector coordinate system; (p x ,p y ,p z ) represents the position of the end effector; Connecting rod length a i , connecting rod torsion angle α i , connecting rod offset d i 、Joint angle θ i Four parameters are used to describe the relative relationship between two adjacent rods, specifically: d i is the distance from the origin of the i-1th coordinate system to Z i-1 Axis and X i The intersection of the axes along the Z i-1 The distance measured by the axis; a i is the length of the common normal line between the axis of joint i and the axis of joint i+1; α i The axis of joint i and the axis of joint i+1 are at the intersection of the axis of joint i and a i The angle on the plane; θ i For Z i-1 Axis from X i-1 Axis steering X i The joint angle of the axis, where i = 1, 2, ..., 6; the initial value represents the angle of each joint in the initial state of the industrial robot; Through the above definition, the transformation relationship is expressed as a matrix express: Among them, Trans(X,l) represents translation transformation, that is, translation l units along the positive direction of the X axis; Rot(X,θ) represents rotation transformation, that is, rotation angle θ around the positive direction of the X axis; Combine equation (1) and equation (2) to obtain the pose matrix of the end effector at the key point:

4. The method for virtual debugging and simulation of an industrial robot based on digital twin according to claim 3 is characterized in that: The inverse kinematics analysis in step S2 is specifically implemented as follows: Inverse kinematics refers to the pose matrix of the end effector Reverse solution for each joint angle θ i (i=1,2,…,6); Separate the expressions of the position and posture of the industrial robot, specifically: Multiply the first three joint coordinate system transformation matrices in equation (1) to the left side of the equation: By taking the matrices on both sides of equation (3) in blocks, we can obtain the equation system: among them, s i =sinθ i ,c i =cosθ i ,s ij =sin(θ i +θ j )c ij =cos(θ i +θ j )(i=1,2,…,6)(j=1,2,…,6); The arctan2(y / x) function is introduced to solve θ in equation (4) to obtain all 8 sets of solutions for the six joint angles: Since the equations in formula (4) can be expressed by the following equation: asinθ i +bcosθ i =c (5) If a, b, c are continuous in this formula, and only if inequality a 2 +b 2 >c 2 When this is true, the equation has a solution: Combining equations (4), (5), and (6), we obtain all eight groups of solutions.

5. The method for virtual debugging and simulation of an industrial robot based on digital twin according to claim 4, characterized in that: The principle of obtaining the optimal solution among the 8 sets of solutions is: Among them, θ ij represents the jth group solution of the ith joint, θ i ′ represents the angle of the i-th joint at the previous point.

6. The method for virtual debugging and simulation of an industrial robot based on digital twin according to claim 1, characterized in that: The specific implementation of step S3 includes: By using process simulation, the digital twin model is given process attributes, so that each process action of the digital twin model of the industrial robot has corresponding motion process logic; Use the timing editor to perform timing simulation on the process attributes of the industrial robot and plan the timing relationship of each process according to the timing table of the action process; Realize the synchronous mapping of industrial robots and their digital twin models: Establish real-time communication between industrial robots and their digital twins; When the control unit of the industrial robot is the communication server, virtual-to-real is realized: the industrial robot transmits its joint data to its digital twin model in real time, and its digital twin model receives the joint data transmitted by the industrial robot and applies steps S1 and S2 to realize synchronous motion; When the control unit of the digital twin model is used as the communication server, virtual control of the real is achieved: the digital twin model sends control instructions to the control unit of the industrial robot, and the industrial robot receives and executes the control instructions.

7. The method for virtual debugging and simulation of an industrial robot based on digital twin according to claim 6, characterized in that: Timing simulation of industrial robots is a time-based simulation.

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