Contact detection method, device and medium for human-machine collaborative grinding

Abstract

The present invention discloses a contact detection method, device and medium for human-machine collaborative grinding, which belongs to the field of target detection and classification. The method includes: obtaining original force data; obtaining force data of a preset time length from the original force data in combination with the current timestamp; calculating a continuous score based on the obtained force data; if the continuous score is higher than the first standard score, calculating an amplitude score based on the obtained force data; if the continuous score is lower than the first standard score, determining that the grinder has not contacted the workpiece; if the amplitude score is higher than the second standard score, determining that the grinder has contacted the workpiece; if the amplitude score is lower than the second standard score, determining that the grinder has not contacted the workpiece. The present invention provides a method for realizing contact detection based on original force data, which is not only simple and convenient, but also has accurate and reliable detection results; in addition, no additional hardware costs are required.

Description

Technical Field

[0001] The present invention relates to the field of target detection and classification, and in particular to a contact detection method, device and medium for human-machine collaborative grinding. Background Art

[0002] Grinding is a machining process that removes excess surface material from a workpiece through the rotation of a grinding machine. It is primarily used during the finishing phase. Early grinding processes relied heavily on manual labor. With the continuous advancement of computer and robotics technology, robotic grinding has emerged. Robots offer the advantages of high precision, long operating times, and minimal fatigue. Therefore, compared to manual grinding, robotic grinding can reduce costs and improve efficiency. However, robots typically move along preset trajectories, limiting their flexibility. Different programs are often required for different scenarios and workpieces, making them suitable for grinding a small number of parts in large batches. Human workers, on the other hand, tend to have greater flexibility and can grind different workpiece types based on processing requirements and their own experience. Therefore, robotic grinding is suitable for grinding a wide variety of parts in small batches.

[0003] To combine the advantages of both robot-based and human-based grinding, improving production efficiency while providing the flexibility to adapt to different scenarios and workpieces, collaborative grinding has emerged. In this method, a grinder and force sensor are mounted on the end of the robot. The robot bears the weight of the grinder and the grinding force of the grinding process. The worker applies external force to the robot to move the end of the robot, thereby moving the grinder to the area to be processed for grinding. In collaborative grinding, the key technology is detecting whether the grinder is in contact with the workpiece, thereby providing a basis for changing the robot's motion pattern. Through simple contact detection methods, the cost of collaborative grinding can be significantly reduced, which is beneficial for enterprises to reduce costs and increase efficiency.

[0004] Currently, there are two main methods for contact and collision detection. The first involves using a pre-set model of the robot and its environment to perform real-time calculations on a computer to determine whether the robot is in contact with the environment. However, this method requires pre-defined models of the robot, operator, and environment, making it difficult to apply to the complex and ever-changing scenarios of collaborative grinding. Furthermore, the modeling process increases the workload, thereby increasing processing costs and reducing efficiency. The second method involves adding additional sensing equipment to enable contact and collision detection. This method does not require modeling of the robot, operator, or environment, offering greater flexibility and applicability. However, the need for additional sensing equipment leads to higher costs. Applying this method to collaborative grinding significantly increases processing costs and reduces corporate profits.

[0005] Therefore, for human-machine collaborative grinding scenarios, there is an urgent need for a simple and reliable contact detection method that can achieve effective and reliable detection of contact between the robot and the workpiece while using low-cost equipment and simple methods. Summary of the Invention

[0006] In order to solve at least one of the technical problems existing in the prior art to a certain extent, the object of the present invention is to provide a contact detection method, device and medium for human-machine collaborative grinding.

[0007] The technical solution adopted in the present invention is:

[0008] A contact detection method for human-machine collaborative grinding comprises the following steps:

[0009] Get raw force data;

[0010] Combined with the current timestamp, force data of a preset time length is obtained from the original force data;

[0011] A continuous score was calculated based on the force data obtained;

[0012] If the continuous score is higher than the first standard score, the amplitude score is calculated based on the obtained force data; if the continuous score is lower than the first standard score, it is determined that the grinder is not in contact with the workpiece;

[0013] If the amplitude score is higher than the second standard score, it is determined that the grinder has contacted the workpiece; if the amplitude score is lower than the second standard score, it is determined that the grinder has not contacted the workpiece.

[0014] Furthermore, the original force data is collected and obtained by a force sensor installed at the end of the robot, and the grinder is connected to the force sensor via a connecting piece.

[0015] Furthermore, the continuous score is calculated in the following way:

[0016] The time period t N -T to t N The force data in the rising section is divided into rising section and falling section, T is the preset time length; the force data of the rising section is expressed as a piecewise function The force data of the descending section is expressed as a piecewise function Each segment of the function is a one-way continuous function and does not cross each other;

[0017] Define the amplitude of a continuous function with a finite independent variable as F r [f(·)]=|f(t0)-f(t n )|, where t0 and t n are the minimum and maximum values ​​of the independent variables respectively, then the evaluation function is designed as:

[0018]

[0019] The continuous score is calculated by this evaluation function; where a is a small positive number close to 0.

[0020] Furthermore, the amplitude score is calculated in the following way:

[0021] G2=|f(t N )-f(t N -T)|

[0022] The larger the score G2 is, the more obvious the characteristics of a significant drop / increase in force data are.

[0023] Another technical solution adopted in the present invention is:

[0024] A contact detection device for human-machine collaborative grinding, comprising:

[0025] at least one processor;

[0026] at least one memory for storing at least one program;

[0027] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0028] Another technical solution adopted in the present invention is:

[0029] A storage medium stores processor-executable instructions, which are used to execute the method described above when executed by a processor.

[0030] The beneficial effects of the present invention are as follows: the present invention provides a method for realizing contact detection based on original force data, which is not only simple and convenient, but also has accurate and reliable detection results; in addition, no additional hardware costs are required. 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, the following introduction is made to the drawings of the embodiments of the present invention or the related technical solutions in the prior art. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative work.

[0032] Figure 1 is a flow chart of a contact detection method for human-machine collaborative grinding according to an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of a human-machine collaborative grinding device according to an embodiment of the present invention;

[0034] Figure 3 This is a typical force data diagram of the grinding machine contacting the workpiece during human-machine collaborative grinding in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention. The step numbers in the following embodiments are provided for ease of explanation only and do not limit the order of the steps. The order of execution of the steps in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0036] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0037] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0038] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0039] In response to the above problems, the present invention determines whether the grinder is in contact with the workpiece based on the contact force data obtained by the force sensor. In human-machine collaborative grinding, it is often necessary to install a force sensor on the end of the robot. In order to save production costs, a force sensor can be used to read all force information, including the gravity of the grinder and its connecting parts, the operator's drag force, the vibration force of the grinder, and the contact force between the grinder and the workpiece during grinding. Since the read force data contains multiple force information, there are certain difficulties in its processing and analysis. The present invention analyzes the characteristics of the force data when the grinder is in contact with the workpiece, and proposes a contact judgment method based on force data.

[0040] like Figure 1As shown, this embodiment provides a contact detection method for human-machine collaborative grinding, comprising the following steps:

[0041] S1. Obtain original force data;

[0042] S2. Based on the original force data, obtain force data for a preset time length forward based on the current timestamp;

[0043] S3, calculate the continuous score based on the obtained force data;

[0044] S4. If the continuous score is higher than the first standard score, the amplitude score is calculated based on the obtained force data; if the continuous score is lower than the first standard score, it is determined that the grinder does not contact the workpiece;

[0045] S5. If the amplitude score is higher than the second standard score, it is determined that the grinder has contacted the workpiece; if the amplitude score is lower than the second standard score, it is determined that the grinder has not contacted the workpiece.

[0046] As an optional implementation, see Figure 2 ,The original force data is collected by a force sensor installed at the end of the robot, and the grinder is connected to the force sensor through a connecting piece.

[0047] The following is a detailed explanation of the duration score and amplitude score.

[0048] First, determine the time length T of the force data used for analysis. If the current time is t N , then t N -T to t N Force data within a time period is used for analysis. Within a certain range, a longer T value increases the accuracy of the judgment result, but reduces real-time performance. Conversely, a shorter T value improves real-time performance but reduces judgment accuracy. In actual production, the appropriate T value must be selected based on different scenarios.

[0049] Analysis of the vibration state of human-robot collaborative grinding equipment reveals that the force data generated when the grinder contacts the workpiece exhibits two characteristics: 1) a continuous increase or decrease; and 2) a large increase or decrease. To address these two characteristics, two evaluation metrics were designed: the "continuity index" and the "amplitude index."

[0050] (1) Continuous indicators

[0051] The time period t N -T to t N The force data in the inner part is divided into ascending section and descending section. The force data in the ascending section can be expressed as a piecewise function The force data of the descending section can be expressed as a piecewise function Each segment of the function is a one-way continuous function and does not cross each other. The amplitude of a continuous function with a finite independent variable is defined as Fr [f(·)]=|f(t0)-f(t n )|, where t0 and t n are the minimum and maximum values ​​of the independent variables respectively. Then the evaluation function of the sustainability index can be designed as:

[0052]

[0053] Here, max(x, y) and min(x, y) represent the larger and smaller of x and y, respectively, and the constant a is a small positive number close to 0. It's easy to see that a larger G1 score indicates better persistence; conversely, a smaller G1 score indicates worse persistence. The persistence score can be calculated using the above function formula.

[0054] (2) Amplitude index

[0055] Because each segment function is a one-way continuous function, for the time period t N -T to t N The force data within the scope of the design is:

[0056] G2=|f(t N )-f(t N -T)| (1)

[0057] Obviously, the larger the score G2 is, the more obvious the characteristics of a sharp drop / increase in the force data are; conversely, the smaller the score G2 is, the weaker the characteristics of the force data fluctuations are.

[0058] Contact detection can be achieved by combining the scores calculated from the force data with the pre-set standard scores using formulas (1) and (2). The standard scores can be adjusted for different processing scenarios and workpieces. If and only if the scores for both the duration and amplitude indicators exceed their respective standard scores, the current state can be considered to be the grinder contacting the workpiece state, and the robot's operating mode can be adjusted accordingly.

[0059] like Figure 2 As shown, a force sensor is mounted on the end of the robot, connected to the grinder via a connector. During operation, the grinder is turned on and the operator drags it to grind the workpiece. Since the entire system in this embodiment uses only one force sensor, the force data it reads includes the weight of the grinder and its connectors, the operator's drag force, the grinder's vibration force, and the pressure between the grinder and the workpiece. This is relatively complex and requires specialized analysis. Figure 3The figure shows typical force data when the operator drags the grinder to contact the workpiece. The dashed box shows the force data during contact. It is not difficult to see that when the grinder contacts the workpiece, the force data has two characteristics: (1) continuous rise / fall and (2) large rise / fall. Therefore, an evaluation method can be designed based on these characteristics to determine whether the grinder contacts the workpiece.

[0060] This embodiment further provides a contact detection device for human-machine collaborative grinding, comprising:

[0061] at least one processor;

[0062] at least one memory for storing at least one program;

[0063] When the at least one program is executed by the at least one processor, the at least one processor implements the following Figure 1 The method shown.

[0064] A contact detection device for human-machine collaborative grinding in this embodiment can execute a contact detection method for human-machine collaborative grinding provided by the method embodiment of the present invention, can execute any combination of implementation steps of the method embodiment, and has the corresponding functions and beneficial effects of the method.

[0065] The present application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device performs Figure 1 The method shown.

[0066] This embodiment also provides a storage medium storing instructions or programs that can execute a contact detection method for human-machine collaborative grinding provided by an embodiment of the method of the present invention. When the instructions or program are run, any combination of implementation steps of the method embodiment can be executed, and the corresponding functions and beneficial effects of the method can be obtained.

[0067] In some optional embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiment presented and described in the flow chart of the present invention is provided in an exemplary manner for the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operation and logic flow presented herein. Optional embodiments are contemplated in which the order of the various operations is changed and the sub-operations described as a part of a larger operation are performed independently.

[0068] Furthermore, although the present invention is described in the context of functional modules, it should be understood that, unless otherwise indicated, one or more of the functions and / or features described may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It will also be understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present invention. More specifically, given the properties, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the module will be understood within the ordinary skill of an engineer. Therefore, a person skilled in the art using ordinary skill will be able to implement the present invention set forth in the claims without undue experimentation. It will also be understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present invention, which is determined by the full scope of the appended claims and their equivalents.

[0069] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each 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.

[0070] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0071] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0072] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0073] In the above description of this specification, reference to the terms "one embodiment / example," "another embodiment / example," or "certain embodiments / examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0074] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

[0075] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A contact detection method for human-machine collaborative grinding, characterized in that: The following steps are involved: Get raw force data; Combined with the current timestamp, force data of a preset time length is obtained from the original force data; A continuous score was calculated based on the force data obtained; If the continuous score is higher than the first standard score, the amplitude score is calculated based on the obtained force data; if the continuous score is lower than the first standard score, it is determined that the grinder is not in contact with the workpiece; If the amplitude score is higher than the second standard score, it is determined that the grinder has contacted the workpiece; if the amplitude score is lower than the second standard score, it is determined that the grinder has not contacted the workpiece; The continuous score is calculated as follows: The time period t N -T to t N The force data in the rising section is divided into rising section and falling section, T is the preset time length; the force data of the rising section is expressed as a piecewise function The force data of the descending section is expressed as a piecewise function Each segment of the function is a one-way continuous function and does not cross each other; Define the amplitude of a continuous function with a finite independent variable as F r [f(·)]=|f(t0)-f(t n )|, where t0 and t n are the minimum and maximum values ​​of the independent variables respectively, then the evaluation function is designed as: Calculate the continuous score through the evaluation function; Where a is a small positive number close to 0.

2. A contact detection method for human-machine collaborative grinding according to claim 1, characterized in that: The original force data is collected and obtained by a force sensor installed at the end of the robot, and the grinder is connected to the force sensor via a connecting piece.

3. The contact detection method for human-machine collaborative grinding according to claim 1, characterized in that: The magnitude score is calculated as follows: G2=|f(t N )-f(t N -T)| The larger G2 is, the more obvious the characteristics of a significant drop / increase in force data are.

4. A contact detection device for human-machine collaborative grinding, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 3.

5. A computer code automatic generation device, characterized in that: The method comprises a memory and a processor, wherein the memory is used to store at least one program, and the processor is used to load the at least one program to execute the method according to any one of claims 1 to 3.

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