Zero-motor fixed-point control method and equipment for tail end arm of spot welding robot

Abstract

The invention provides a spot welding robot tail end arm zero motor fixed point control method and equipment. The method comprises the following steps: constructing a kinetic model of the spot welding robot, and converting the kinetic model into a second-order control model; the second-order control model is converted into a first-order controllable model through the intermediate parameters, and the path constraint condition of movement of the tail end arm of the spot welding robot is determined according to the first-order controllable model; determining a first joint controller and a second joint controller of the spot welding robot by adopting the path constraint condition and a first-order controllable model; and a first joint controller and a second joint controller are adopted to control the kinetic model, and it is ensured that the tail end arm of the spot welding robot moves to a preset point position. Dependence of the spot welding robot on an execution motor can be reduced, the production cost of industrial products machined by the spot welding robot is reduced, and the market competitiveness of the industrial products is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of industrial manipulators, and in particular to a method and device for zero-motor fixed-point control of an end arm of a spot welding robot. Background Art

[0002] At present, spot welding robots are widely used in industrial production and processing. Traditional spot welding robots use a single arm and a single joint to be controlled by a single motor to perform spot welding on the corresponding parts of industrial products, which has the advantages of simple control and easy deployment. However, when it is necessary to expand the spot welding range, it is necessary to add two robotic arms and two controlled joints accordingly. The relevant technologies currently use three controlled motors to control and execute the three controlled joints respectively. Although the spot welding robot can be effectively controlled to the corresponding position for spot welding, due to the addition of two controlled motors and the large number of spot welding robots used in large-scale industrial production, the large number of additional motors will greatly increase the equipment cost, thereby raising the product price and reducing the market competitiveness of the product. Therefore, the development of a zero-motor fixed-point control method and equipment for the end arm of a spot welding robot can effectively overcome the defects in the above-mentioned related technologies, which has become a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0003] In view of the above problems existing in the prior art, an embodiment of the present invention provides a method and device for zero-motor fixed-point control of an end arm of a spot welding robot.

[0004] In the first aspect, an embodiment of the present invention provides a zero-motor fixed-point control method for the end arm of a spot welding robot, comprising: constructing a dynamic model of the spot welding robot, and converting the dynamic model into a second-order control model; using intermediate parameters to convert the second-order control model into a first-order controllable model, and determining the path constraint conditions for the movement of the end arm of the spot welding robot according to the first-order controllable model; using the path constraint conditions and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot; using the first joint controller and the second joint controller to control the dynamic model to ensure that the end arm of the spot welding robot moves to a predetermined position.

[0005] Based on the content of the above method embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, the construction of the dynamic model of the spot welding robot includes:

[0006]

[0007]

[0008] Among them, m f is the mass of the first end arm; m s is the mass of the middle arm; m tis the mass of the end arm; x t is the horizontal coordinate of the end joint; y t is the ordinate of the end joint; is the angle between the end arm and the horizontal axis; sec is the symbol of the secant function; tan is the symbol of the tangent function; d is the distance from the center of gravity of the end arm to the end joint; F f is the first end joint torque; F s is the mid-joint torque; J t is the moment of inertia of the end arm around the end joint; ● is the derivative with respect to time.

[0009] Based on the content of the above method embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, wherein the dynamic model is converted into a second-order control model, comprises:

[0010] Second-order control model:

[0011]

[0012] Among them, n f is the first conversion variable; n s is the second conversion variable; n t is the third conversion variable; c f is the first conversion control variable; c s is the second conversion control variable; cos is the sign of the cosine function; sin is the sign of the sine function.

[0013] Based on the content of the above method embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, wherein the intermediate parameters are used to convert the second-order control model into a first-order controllable model, comprises:

[0014] First-order controllable model:

[0015]

[0016] Among them, u 1 is the first intermediate parameter; u 2 is the second intermediate parameter; s 1 is the first intermediate variable; s 2 is the second intermediate variable; s 3 is the third intermediate variable; w is the fourth intermediate variable.

[0017] Based on the content of the above method embodiment, the zero motor fixed point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, the path constraint conditions of the end arm movement of the spot welding robot are determined according to the first-order controllable model, including: satisfying n f >0,-u1 -k 1 n f ≤0 or n f <0,-u 1 -k 1 n f ≥0; where k 1 is the first control coefficient.

[0018] Based on the content of the above method embodiment, the zero motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention adopts the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot, including: if the path constraint condition is met, then

[0019]

[0020] Among them, k 2 is the second control coefficient; σ is a non-zero constant; δ 1 is the first adjustment factor.

[0021] Based on the content of the above method embodiment, the zero motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention adopts the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot, and also includes: if the path constraint condition is not met, then

[0022]

[0023] Among them, δ 2 is the second adjustment coefficient; δ 3 is the third adjustment coefficient; and δ 1 , δ 2 and δ 3 make sure is the Hurwitz matrix.

[0024] In the second aspect, an embodiment of the present invention provides a zero-motor fixed-point control device for the end arm of a spot welding robot, comprising: a first main module, used to realize the construction of a dynamic model of the spot welding robot and convert the dynamic model into a second-order control model; a second main module, used to realize the conversion of the second-order control model into a first-order controllable model using intermediate parameters, and determine the path constraint conditions for the movement of the end arm of the spot welding robot according to the first-order controllable model; a third main module, used to realize the use of the path constraint conditions and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot; a fourth main module, used to realize the use of the first joint controller and the second joint controller to control the dynamic model to ensure that the end arm of the spot welding robot moves to a predetermined position.

[0025] In a third aspect, an embodiment of the present invention provides an electronic device, including:

[0026] At least one processor, at least one memory and a communication interface; wherein,

[0027] The processor, memory and communication interface communicate with each other;

[0028] The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the zero-motor fixed-point control method for the end arm of a spot welding robot provided by any one of the various implementations of the first aspect.

[0029] In a fourth aspect, an embodiment of the present invention provides a non-transitory computer-readable storage medium, which stores computer instructions, and the computer instructions enable a computer to execute a zero-motor fixed-point control method for an end arm of a spot welding robot provided in any one of the various implementation methods of the first aspect.

[0030] The zero-motor fixed-point control method and device for the end arm of a spot welding robot provided in an embodiment of the present invention convert the dynamic model of the spot welding robot into a first-order controllable model and determine the path constraints for the movement of the end arm of the spot welding robot. On this basis, a first joint controller and a second joint controller are constructed, and a dual controller is used to ensure that the end arm of the spot welding robot moves to a predetermined position. This can reduce the dependence of the spot welding robot on the actuator motor, reduce the production cost of industrial products processed by the spot welding robot, and improve the market competitiveness of industrial products. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic flow chart of a zero-motor fixed-point control method for a spot welding robot end arm provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of a zero-motor fixed-point control device for the end arm of a spot welding robot provided in an embodiment of the present invention;

[0034] Figure 3 A schematic diagram of the physical structure of an electronic device provided by an embodiment of the present invention;

[0035] Figure 4 A schematic diagram of the control effect of the end joint provided by an embodiment of the present invention;

[0036] Figure 5 Schematic diagram of the control torque applied by the head end joint and the middle end joint provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme in the embodiment of the present invention will be clearly and completely described in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention can be combined with each other arbitrarily to form a feasible technical solution. This combination is not subject to the constraints of the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that the combination of such technical solutions does not exist and is not within the scope of protection required by the present invention. If there are step numbers in the following embodiments, they are only set for the convenience of explanation, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0038] The embodiment of the present invention provides a method for controlling the zero motor fixed point of the end arm of a spot welding robot, see Figure 1 The method includes: constructing a dynamic model of a spot welding robot and converting the dynamic model into a second-order control model; using intermediate parameters to convert the second-order control model into a first-order controllable model, and determining the path constraint conditions of the movement of the end arm of the spot welding robot according to the first-order controllable model; using the path constraint conditions and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot; using the first joint controller and the second joint controller to control the dynamic model to ensure that the end arm of the spot welding robot moves to a predetermined position.

[0039] Based on the content of the above method embodiment, as an optional embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, the construction of the dynamic model of the spot welding robot includes:

[0040]

[0041] Among them, m f is the mass of the first end arm; m s is the mass of the middle arm; m t is the mass of the end arm; x t is the horizontal coordinate of the end joint; y tis the ordinate of the end joint; is the angle between the end arm and the horizontal axis; sec is the symbol of the secant function; tan is the symbol of the tangent function; d is the distance from the center of gravity of the end arm to the end joint; F f is the first end joint torque; F s is the mid-joint torque; J t is the moment of inertia of the end arm around the end joint; ● is the derivative with respect to time. It should be noted that, from the dynamic model of the spot welding robot, it can be seen that the spot welding robot is linear and uncontrollable, so the following model transformation is required to convert it into a linear controllable model, and then design the relevant linear controller. It should be noted that since the spot welding robot targeted by this technical solution is placed horizontally, there is no need to consider the influence of gravity on the torque of the head arm, the middle arm and the end arm, and try to lubricate each joint as much as possible, so that the influence of friction can be ignored during modeling.

[0042] Based on the content of the above method embodiment, as an optional embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, wherein the dynamic model is converted into a second-order control model, comprises:

[0043] Second-order control model:

[0044]

[0045]

[0046] Among them, n f is the first conversion variable; n s is the second conversion variable; n t is the third conversion variable; c f is the first conversion control variable; c s is the second conversion control variable; cos is the sign of the cosine function; sin is the sign of the sine function.

[0047] Based on the content of the above method embodiment, as an optional embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, wherein the intermediate parameters are used to convert the second-order control model into a first-order controllable model, comprises:

[0048] First-order controllable model:

[0049]

[0050] Among them, u 1 is the first intermediate parameter; u 2 is the second intermediate parameter; s 1 is the first intermediate variable; s2 is the second intermediate variable; s 3 is the third intermediate variable; w is the fourth intermediate variable. Specifically, according to the first-order controllable model, the first conversion control variable c can be designed by the linear design method. f and the second conversion control variable c s , and control the head end joint and the middle end joint accordingly.

[0051] Based on the content of the above method embodiment, as an optional embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention, the path constraint conditions of the end arm movement of the spot welding robot are determined according to the first-order controllable model, including: satisfying n f >0,-u 1 -k 1 n f ≤0 or n f <0,-u 1 -k 1 n f ≥0; where k 1 is the first control coefficient. It should be noted that the path constraint condition limits the movement of the end arm to a relatively ideal situation, which excludes n f =0, which makes it easier to design a linear controller.

[0052] Based on the content of the above method embodiment, as an optional embodiment, the zero-motor fixed-point control method of the end arm of the spot welding robot provided in the embodiment of the present invention adopts the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot, including: if the path constraint condition is met, then

[0053]

[0054] Among them, k 2 is the second control coefficient; σ is a non-zero constant; δ 1 is the first adjustment factor.

[0055] Based on the content of the above method embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed-point control method provided in the embodiment of the present invention adopts the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot, and also includes: if the path constraint condition is not met, then there is

[0056]

[0057] Among them, δ 2 is the second adjustment coefficient; δ 3 is the third adjustment coefficient; and δ1 , δ 2 and δ 3 make sure is the Hurwitz matrix.

[0058] The zero-motor fixed-point control method for the end arm of a spot welding robot provided in an embodiment of the present invention converts the dynamic model of the spot welding robot into a first-order controllable model and determines the path constraints for the movement of the end arm of the spot welding robot. On this basis, a first joint controller and a second joint controller are constructed, and a dual controller is used to ensure that the end arm of the spot welding robot moves to a predetermined position. This can reduce the dependence of the spot welding robot on the actuator motor, reduce the production cost of industrial products processed by the spot welding robot, and improve the market competitiveness of industrial products.

[0059] The control effect of the zero motor fixed point control method for the end arm of the spot welding robot provided by the embodiment of the present invention can be seen in Figure 4 and Figure 5 When simulating the system, set m f =m s =m t =1,d=1,k 1 =1, k 2 =2, Hurwitz matrix The eigenvalues ​​are set to (-1, -2, -3), σ = 0.6, and the angles between the horizontal and vertical coordinates of the end joint and the direction of the horizontal coordinate axis of the end arm in the initial state are x t =0,y t =0, Equivalent to n in the first-order controllable model f =-2.8, n s =0.3, n t =-0.5. By adopting the first conversion control variable c in the technical solution of the present invention f and the second conversion control variable c s After controlling the head joint and the middle joint, the horizontal and vertical coordinates of the terminal joint and the angle between the terminal arm and the horizontal axis are stabilized at x t =2,y t =2, First end joint torque F f And mid-end joint torque F s It also stabilized from the initial 13 and 8 Newtons to zero Newton (that is, after the control is in place, the motor output torque is no longer needed).

[0060] The implementation basis of each embodiment of the present invention is to implement programmed processing through a device with a processor function. Therefore, in engineering practice, the technical solutions and functions of each embodiment of the present invention can be encapsulated into various modules. Based on this reality, on the basis of the above embodiments, an embodiment of the present invention provides a zero-motor fixed-point control device for the end arm of a spot welding robot, which is used to execute the zero-motor fixed-point control method for the end arm of a spot welding robot in the above method embodiment. Figure 2 The device includes: a first main module, which is used to build a dynamic model of the spot welding robot and convert the dynamic model into a second-order control model; a second main module, which is used to convert the second-order control model into a first-order controllable model using intermediate parameters, and determine the path constraint conditions of the movement of the end arm of the spot welding robot according to the first-order controllable model; a third main module, which is used to determine the first joint controller and the second joint controller of the spot welding robot using the path constraint conditions and the first-order controllable model; and a fourth main module, which is used to control the dynamic model using the first joint controller and the second joint controller to ensure that the end arm of the spot welding robot moves to a predetermined position.

[0061] The zero-motor fixed-point control device for the end arm of a spot welding robot provided by the embodiment of the present invention adopts Figure 2 Several modules in it, by converting the dynamic model of the spot welding robot into a first-order controllable model and determining the path constraints of the movement of the end arm of the spot welding robot, on this basis, constructing the first joint controller and the second joint controller, and using dual controllers to ensure that the end arm of the spot welding robot moves to the predetermined point, can reduce the spot welding robot's dependence on the actuator motor, reduce the production cost of industrial products processed by the spot welding robot, and improve the market competitiveness of industrial products.

[0062] It should be noted that the device in the device embodiment provided by the present invention can be used to implement the method in the above method embodiment as well as the method in other method embodiments provided by the present invention. The only difference is that the corresponding functional modules are set, and the principle is basically the same as the principle of the above device embodiment provided by the present invention. As long as the technical personnel in the field refer to the specific technical solutions in other method embodiments on the basis of the above device embodiment, obtain the corresponding technical means and the technical solutions composed of these technical means by combining technical features, the device in the above device embodiment can be improved on the premise of ensuring the practicality of the technical solution, thereby obtaining the corresponding device class embodiment, which is used to implement the methods in other method class embodiments. For example:

[0063] Based on the content of the above device embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed-point control device provided in the embodiment of the present invention further includes: a first submodule, which is used to implement the construction of the dynamic model of the spot welding robot, including:

[0064]

[0065] Among them, m f is the mass of the first end arm; m s is the mass of the middle arm; m t is the mass of the end arm; x t is the horizontal coordinate of the end joint; y t is the ordinate of the end joint; is the angle between the end arm and the horizontal axis; sec is the symbol of the secant function; tan is the symbol of the tangent function; d is the distance from the center of gravity of the end arm to the end joint; F f is the first end joint torque; F s is the mid-joint torque; J t is the moment of inertia of the end arm around the end joint; ● is the derivative with respect to time.

[0066] Based on the content of the above device embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed-point control device provided in the embodiment of the present invention further includes: a second submodule for realizing the conversion of the dynamic model into a second-order control model, including:

[0067] Second-order control model:

[0068]

[0069]

[0070] Among them, n f is the first conversion variable; n s is the second conversion variable; n t is the third conversion variable; c f is the first conversion control variable; c s is the second conversion control variable; cos is the sign of the cosine function; sin is the sign of the sine function.

[0071] Based on the content of the above device embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed-point control device provided in the embodiment of the present invention further includes: a third submodule, which is used to realize the conversion of the second-order control model into a first-order controllable model using intermediate parameters, including:

[0072] First-order controllable model:

[0073]

[0074] Among them, u 1 is the first intermediate parameter; u 2 is the second intermediate parameter; s 1 is the first intermediate variable; s 2 is the second intermediate variable; s 3 is the third intermediate variable; w is the fourth intermediate variable.

[0075] Based on the content of the above device embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed point control device provided in the embodiment of the present invention also includes: a fourth submodule, which is used to implement the path constraint conditions for the movement of the spot welding robot end arm determined according to the first-order controllable model, including: satisfying n f >0,-u 1 -k 1 n f ≤0 or n f <0,-u 1 -k 1 n f ≥0; where k 1 is the first control coefficient.

[0076] Based on the content of the above device embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed-point control device provided in the embodiment of the present invention also includes: a fifth submodule, which is used to implement the use of the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot, including: if the path constraint condition is met, then

[0077]

[0078] Among them, k 2 is the second control coefficient; σ is a non-zero constant; δ 1 is the first adjustment factor.

[0079] Based on the content of the above device embodiment, as an optional embodiment, the spot welding robot end arm zero motor fixed-point control device provided in the embodiment of the present invention also includes: a sixth submodule, which is used to implement the use of the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot, and also includes: if the path constraint condition is not met, then there is

[0080]

[0081] Among them, δ 2 is the second adjustment coefficient; δ 3 is the third adjustment coefficient; and δ1 , δ 2 and δ 3 make sure is the Hurwitz matrix.

[0082] The method of the embodiment of the present invention is implemented by relying on electronic devices, so it is necessary to introduce the relevant electronic devices. Based on this purpose, the embodiment of the present invention provides an electronic device, such as Figure 3 As shown, the electronic device includes: at least one processor, a communication interface, at least one memory, and a communication bus, wherein at least one processor, the communication interface, and at least one memory communicate with each other through the communication bus. At least one processor can call the logic instructions in at least one memory to execute all or part of the steps of the method provided by the aforementioned various method embodiments.

[0083] In addition, the logic instructions in the at least one memory mentioned above can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on this understanding, the technical solution of the present invention can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each method embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0084] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0085] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiment.

[0086] The flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. Based on this understanding, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and sometimes in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of the boxes in the block diagram and / or the flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0087] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "includes..." do not exclude the existence of other identical elements in the process, method, article or device including the elements. Any "predetermined threshold", "preset threshold" and other similar expressions that do not indicate specific values ​​can be determined by a person of ordinary skill in the art through simple experiments or corresponding debugging.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the zero motor fixed point of a spot welding robot end arm, characterized in that: include: Construct the dynamic model of the spot welding robot and convert the dynamic model into a second-order control model; The second-order control model is converted into a first-order controllable model by using intermediate parameters, and the path constraint conditions of the movement of the end arm of the spot welding robot are determined according to the first-order controllable model; the first joint controller and the second joint controller of the spot welding robot are determined by using the path constraint conditions and the first-order controllable model; the first joint controller and the second joint controller are used to control the dynamic model to ensure that the end arm of the spot welding robot moves to a predetermined position.

2. The spot welding robot end arm zero motor fixed point control method according to claim 1, characterized in that: The construction of the dynamic model of the spot welding robot includes: Among them, m f is the mass of the first end arm; m s is the mass of the middle arm; m t is the mass of the end arm; x t is the horizontal coordinate of the end joint; y t is the ordinate of the end joint; is the angle between the end arm and the horizontal axis; sec is the symbol of the secant function; tan is the symbol of the tangent function; d is the distance from the center of gravity of the end arm to the end joint; F f is the first end joint torque; F s is the mid-joint torque; J t is the moment of inertia of the end arm around the end joint; ● is the derivative with respect to time.

3. The spot welding robot end arm zero motor fixed point control method according to claim 2, characterized in that: The converting of the dynamic model into a second-order control model comprises: Second-order control model: Among them, n f is the first conversion variable; n s is the second conversion variable; n t is the third conversion variable; c f is the first conversion control variable; c s is the second conversion control variable; cos is the sign of the cosine function; sin is the sign of the sine function.

4. The spot welding robot end arm zero motor fixed point control method according to claim 3, characterized in that: The method of converting the second-order control model into a first-order controllable model by using intermediate parameters includes: First-order controllable model: Among them, u1 is the first intermediate parameter; u2 is the second intermediate parameter; s1 is the first intermediate variable; s2 is the second intermediate variable; s3 is the third intermediate variable; w is the fourth intermediate variable.

5. The spot welding robot end arm zero motor fixed point control method according to claim 4, characterized in that: The path constraint conditions for the movement of the end arm of the spot welding robot are determined according to the first-order controllable model, including: satisfying n f >0,-u1-k1n f ≤0 or n f <0,-u1-k1n f ≥0; where k1 is the first control coefficient.

6. The method for controlling the zero motor fixed point of the end arm of a spot welding robot according to claim 5, characterized in that: The method of using the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot includes: if the path constraint condition is met, then Wherein, k2 is the second control coefficient; σ is a non-zero constant; δ1 is the first adjustment coefficient.

7. The method for controlling the zero motor fixed point of the end arm of a spot welding robot according to claim 6, characterized in that: The method of using the path constraint condition and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot also includes: if the path constraint condition is not met, then Among them, δ2 is the second adjustment coefficient; δ3 is the third adjustment coefficient; and δ1, δ2 and δ3 ensure is the Hurwitz matrix.

8. A spot welding robot end arm zero motor fixed point control device, characterized in that: include: The first main module is used to realize the construction of the dynamic model of the spot welding robot and convert the dynamic model into a second-order control model; The second main module is used to convert the second-order control model into a first-order controllable model by using intermediate parameters, and determine the path constraint conditions of the end arm movement of the spot welding robot according to the first-order controllable model; The third main module is used to implement the path constraint conditions and the first-order controllable model to determine the first joint controller and the second joint controller of the spot welding robot; the fourth main module is used to implement the first joint controller and the second joint controller to control the dynamic model to ensure that the end arm of the spot welding robot moves to a predetermined point.

9. An electronic device, characterized in that: include: At least one processor, at least one memory and a communication interface; wherein, The processor, memory and communication interface communicate with each other; The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium, characterized in that: The non-transitory computer-readable storage medium stores computer instructions, which cause a computer to execute the method of any one of claims 1 to 7.

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