Safety control method and system for preventing industrial robot from falling due to misoperation

Abstract

The invention discloses a robot system with a misoperation falling prevention protection function and a use method of the robot system. The method comprises the steps that by rewriting a bottom layer parameter file of a robot control system, an output signal related to clamping jaw control is configured to be in a read-only mode, so that manual forced output or key false triggering is forbidden; a position verification function module is developed, a target coordinate X is input, a current actual coordinate Y of the robot is obtained, and a difference value Z of the X and the Y in translation, posture and external axis dimensions is calculated; a verification logic is integrated in a claw loosening or releasing control program, and only when a difference value Z is within a preset tolerance range N (such as 0.1 mm), an action signal is allowed to be output; and packaging the control logic into an encrypted function module. Starting from the two aspects of bottom layer authority and spatial position accurate verification, the workpiece or clamp falling accident caused by manual misoperation is fundamentally eradicated, zero-falling protection is achieved, no sensor needs to be additionally arranged, and system safety and operation convenience are both considered.

Description

Technical Field

[0001] This invention belongs to the field of industrial robot technology, and specifically discloses a safety control method and system for preventing industrial robots from falling due to misoperation. Background Technology

[0002] Today, industrial robots are widely used in various fields of modern industrial production and manufacturing, undertaking heavy and complex tasks such as handling, assembly, and welding. In practical applications of industrial robots, the end effector is usually equipped with grippers or tool-side quick-change discs for grasping and placing various parts.

[0003] However, safety issues are becoming increasingly prominent during the daily teaching, program debugging, and manual intervention of robots. One of the most significant safety hazards is that operators are highly susceptible to misoperation due to fatigue, obstructed vision, or accidental button presses when using the robot teach pendant. This can cause the robot to unexpectedly execute "release gripper" or "disengage quick-change plate" commands from outside the intended position. Such misoperation can directly cause parts or tools on the gripper to fall, resulting in workpiece scrap, gripper damage, and damage to surrounding equipment, or even serious personal injury or death. The danger and destructiveness of such falls increase exponentially, especially when the robot is handling heavy workpieces weighing hundreds of kilograms or even tons.

[0004] To reduce the risk of falls caused by the aforementioned misoperations, the automation industry currently mainly uses the following two conventional safety protection methods, but both have obvious limitations and shortcomings: The first existing method is to use the "safe zone restriction method".

[0005] This method establishes a three-dimensional safety zone for each device the robot needs to serve in a background program and determines in real time whether the robot is currently within that safety zone. The system only allows the operator to execute release or detach commands when the robot is within the safety zone. However, this method has several vulnerabilities in practical applications: Protection vacuum period: In the early stage of project commissioning, when the safety zone has not been set up or the protection program has not been fully activated, the system lacks protection mechanism and accidental fall may still occur at any time.

[0006] Limited number of safe zones: Due to the limitations of the underlying settings of the robot control system, only a limited number (e.g., 8) of safe zones can usually be set, while the actual number of devices on the production line often far exceeds this limit, resulting in some workstations not being protected.

[0007] Insufficient protection precision: To accommodate the physical boundaries of the equipment, the defined safety zone is usually much larger than the actual receiving size of the equipment itself. Therefore, even if the robot's end effector is within the safety zone, if it is not at the precise placement point, misoperation can still cause the workpiece to fall from a height within the safety zone, making it impossible to achieve "zero falls".

[0008] The second existing method is to use the "PLC stripping control method".

[0009] This method severs the robot's direct control over the gripper at the system level. When gripper operation is required, the robot only sends a request signal to the external PLC. Subsequently, an operator must perform secondary confirmation and manual operation on the PLC's touchscreen interface to release the gripper or detach the quick-change tray. While this method increases the operational threshold to some extent, thereby reducing errors, it also introduces new problems: Accidental touches cannot be completely eliminated: Touchscreen interfaces still have a small probability of accidental touches, and the possibility of misoperation cannot be fundamentally eliminated.

[0010] The process is cumbersome and introduces new risks: On-site teaching and debugging becomes extremely complicated, usually requiring two operators (one operating the PLC touchscreen next to the control cabinet, and the other operating the robot with a teach pendant). Due to blind spots between the two operators, they often cannot see each other, which can easily lead to communication problems or improper timing of operations, causing the robot's gripper to squeeze or collide with the operator holding the teach pendant, thus introducing new personal safety hazards.

[0011] Existing robot gripper control technology cannot fundamentally eliminate safety hazards caused by human error, and also seriously affects the convenience of on-site debugging and operation. Therefore, the industry urgently needs a robot safety control solution that can completely prevent workpieces from falling off due to misoperation, achieving "zero drop" protection, without adding complex hardware or affecting operational convenience. Summary of the Invention

[0012] The purpose of this invention is to address the safety hazard in existing technologies where, during the teaching or debugging process of industrial robots, operators may accidentally touch shortcut keys or force output signals on the teach pendant, leading to the accidental drop of the robot's end effector gripper or workpiece. This invention provides a safety control method and system to prevent accidental drops by industrial robots. Specifically, this invention aims to solve the following technical problems: 1. How to completely eliminate the permission for manual triggering of gripper actions via shortcut keys or the I / O interface at the system level; 2. How to achieve accurate verification of the spatial position of the robot when performing gripper actions without adding external sensors; 3. How to balance operational convenience and system logic versatility while ensuring safety.

[0013] To address the aforementioned technical problems, this invention proposes a safety control method to prevent industrial robots from accidentally falling, characterized by the following steps: S1. Low-level signal permission restriction: By rewriting the low-level parameter file of the output signals (such as release signal and release signal) related to gripper control in the robot control system, the attribute of the output signal is configured to read-only (RO) mode, so that the signal cannot be triggered by manual forced output or teach pendant shortcut key, but can only be triggered by the preset control program block logic.

[0014] S2. Develop a position verification function module: Write a program block with position comparison function, input the target point coordinates X and the preset tolerance range N; when the program runs, it automatically obtains the reference coordinate system F corresponding to the target point coordinates X, and obtains the robot's actual coordinates Y under the reference coordinate system F in real time.

[0015] S3. Perform precise difference calculation: Calculate the difference Z between the target point coordinate X and the actual coordinate Y in six dimensions (X, Y, Z axis translation and A, B, C rotation angles) and the external axis (E1, E2, E3), and determine whether the absolute value of each element in the difference Z is within the tolerance range N.

[0016] S4. Action Execution Interlock: The position verification logic is integrated into the control command set of the gripper or quick-change disc. The system only allows the execution of the corresponding gripper release or disengagement program command when the difference Z is within the tolerance range N; if the difference exceeds the tolerance range, the system intercepts the output signal and triggers an alarm to prevent the drop from occurring at the wrong position.

[0017] S5. Encapsulation and Encryption of Control Logic: The above position verification and action execution logic is encapsulated into a reusable function module, and the module is encrypted to prevent unauthorized tampering.

[0018] The present invention also provides a safety control system for performing the above method, comprising: Parameter configuration module: Used to modify the robot's underlying I / O parameters and prevent manual intervention in the output of specific signals; Position calculation unit: used to acquire and calculate the deviation between the target position and the actual position in real time; Logic verification unit: used for performing tolerance comparison and interlock control of execution permissions; Encryption encapsulation module: Used for modular encapsulation and encryption protection of security control logic.

[0019] Compared with existing technologies, this invention has the following significant advantages: 1. Extremely high security ("zero drop"): This invention fundamentally eliminates drop accidents caused by human error or accidental button presses on the teach pendant through dual protection of low-level access control and high-precision position verification (e.g., 0.1mm level), solving the drawback of the excessively large protection range of the traditional "safe zone" method. 2. Ease of operation and safety coexist: Unlike traditional methods, it does not rely on two people or external PLC operation. A single person can safely complete the debugging work on the teach pendant, and the program automatically performs position verification, which improves efficiency and eliminates the hidden dangers of blind spots in collaboration. 3. Low system integration cost: This solution is entirely based on the internal program logic and parameter settings of the robot system, without the need for additional physical sensors or external hardware devices, reducing the complexity and maintenance cost of the system. 4. Good versatility and stability: Adopting a modular design, it can be easily ported to industrial robot systems of different brands and models. Encryption processing effectively improves the robustness of the system and prevents logical failures caused by arbitrary program tampering. 5. Suitable for high-precision scenarios: It is particularly suitable for applications with extremely high safety and precision requirements, such as heavy workpiece handling and aerospace assembly, and has extremely high promotion value and economic benefits. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments disclosed in this invention, the accompanying drawings of the embodiments will be briefly described below. These drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0021] Figure 1 This is a schematic diagram of the state of the KUKA robot after the underlying parameters of the output signal have been rewritten in an embodiment of the present invention, showing the effect of setting the output signal to RO (read-only) mode; Figure 2 This is a flowchart of the position verification function block in an embodiment of the present invention, showing the logical steps from inputting the target point to outputting the verification result; Figure 3 This is an example code diagram illustrating position verification and execution of disengagement commands in the robot's operating program, as described in this embodiment of the invention. Figure 4 This is a schematic diagram of the interface of the KUKA robot teach pendant in an embodiment of the present invention. The diagram shows the location of the gripper control shortcut button whose control permissions have been revoked. Figure 5 This is a call example diagram of the encapsulated gripper-specific control program block (Grip_Open / Grip_Close) in an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] This embodiment uses the common KUKA industrial robot as an example for description, but those skilled in the art should understand that the method and logic of the present invention are also applicable to robot control systems of other brands such as ABB, FANUC, and Yaskawa, simply by calling their corresponding system variables and syntax.

[0024] This invention proposes a robot system and its safety control method with protection against accidental falls. The core idea is to replace the traditional "safety zone method," which has blind spots, with a multi-layered protection mechanism of "access restrictions + high-precision position verification + program block interlocking." The specific implementation steps are as follows: S1: Redefinition of underlying output permissions In traditional robot configurations, operators can manually force the output signal to go up or down via the teach pendant's I / O monitoring interface. To eliminate this potential hazard, this embodiment first rewrites the underlying parameter file of the robot control system.

[0025] like Figure 1 As shown, modify the access attribute of the output signals related to gripper opening and closing and tool quick-change disc disengagement to RO (Read-Only). After rewriting, as shown... Figure 1 As shown in the status bar, these signals are now read-only. At this point, even if the operator attempts to manually click the signal to force output via the teach pendant interface, the system will intercept the command. This ensures that gripper action signals can only be triggered through preset logic programs, eliminating the risk of accidental interface touches at the source.

[0026] S2: Develop a location verification function module This invention develops a standardized location verification function package. Its workflow is as follows: Figure 2 As shown, the specific logic is as follows: 1. Parameter Input: Set two input parameters for the function block: target coordinate point X and tolerance range N (in this embodiment, N is 0.1mm). 2. Coordinate System Matching: After the program runs, it will automatically obtain the target coordinate point. The bound reference coordinate system (including tool coordinate system) and workpiece coordinate system 3. Obtain real-time position: The system reads the robot's end effector's position in the current reference coordinate system in real time. The actual spatial coordinates below 4. Calculate the difference: Calculate and Deviation values ​​in nine dimensions ,Right now ,in For attitude Euler angles, These are the external axis coordinates of the robot.

[0027] Develop a position verification function package to implement the following functions: (1) Input a coordinate X and a position tolerance range N, and the program will automatically obtain the reference coordinate system F{Toolx,Basex} of coordinate X. The reference coordinate system F includes the tool coordinate system Toolx and the workpiece coordinate system Basex; (2) Calculate the current coordinate Y of the robot in the reference coordinate system F{Toolx,Basex}; (3) Calculate the difference Z{x,y,z,a,b,c,E1,E2,E3} between coordinates X and Y; (4) Compare the absolute value of each element in the tolerance range N with the absolute value of each element in the difference Z{x,y,z,a,b,c,E1,E2,E3}. When N is less than or equal to the absolute value of each element in Z, the program block returns TRUE, otherwise it returns FALSE. That is, the following conditions must be met: |Zx|<=N; |Zy|<=N; |Zz|<=N; |Za|<=N; |Zb|<=N; |Zc|<=N; |Z.E1|<=N; |Z.E2|<=N; |Z.E3|<=N; In practical applications, N is typically set to 0.1 mm, meaning that when the robot executes the gripper release and release commands, the position must not deviate from the program-defined position by more than 0.1 mm. S3: Precise Position Verification and Logic Interlocking Before executing the release or disengagement command, the system performs the following comparison and judgment: [Judgment] Are the absolute values ​​of each element in the set all less than or equal to the tolerance? That is, the following must be satisfied simultaneously: ; ; ; ; ; ; ; ; Verification Passed: If all the above conditions are met, the function returns TRUE, and the system allows subsequent gripper release or disengagement physical actions to be executed. Verification Failed: If the deviation in any dimension exceeds 0.1mm, the function returns FALSE. At this time, the system immediately triggers an alarm, displays a "Position Deviation Too Large" message, and executes the HALT command to forcibly terminate the current program.

[0028] The control commands for releasing or disengaging the gripper are grouped into independent program blocks, named GripOpen and ToolUnLock respectively. These two blocks then call the position verification program block developed in the preceding steps. When the robot executes the release or disengagement program block, the program first verifies whether the current robot position matches the position set in the program, with an allowable deviation not exceeding the set tolerance N. If the verification passes, the corresponding release or disengagement command is executed; if the verification fails, an alarm is triggered and program execution is terminated. This ensures that even if the operator executes the release or disengagement command in an incorrect position, the robot program will self-protect.

[0029] like Figure 3 As shown, this is the program PutGrip1 for the robot to release the gripper. The coordinate point XGrip1Put is the correct release point for the robot. In other words, in the program PutGrip1, only the coordinate point XGrip1Put is the correct release point. Releasing the gripper at any other position is extremely dangerous.

[0030] When the robot reaches the coordinate point XGrip1Put, the ToolUnLock block will be executed. The coordinate variable input to the ToolUnLock block is XGrip1Put. The program will first verify whether the current robot position in the FGrip1Put coordinate system matches the XGrip1Put position. Only if the position verification matches and does not exceed the tolerance range N will the release command be executed to ensure safety.

[0031] If multiple motion subroutines require the execution of the gripper release or release command, simply change the input coordinates after the GripOpen or ToolUnLock block. For example, the gripper release command in the Grip2Put program is ToolUnLock(XGrip2Put, FGrip2Put). During program execution, the program will automatically detect whether the robot's current coordinate position matches the XGrip2Put coordinate.

[0032] S4: Modification of the teach pendant interface like Figure 4 As shown, in traditional operation, the shortcut buttons (shortcut keys) on the side of the teach pendant are often defined as gripper controls, which can easily lead to accidental activation. In this embodiment, the associated permissions of these shortcut buttons are canceled through system settings.

[0033] Instead, new additions such as Figure 5The "gripper-specific control program block" is shown. When the operator needs to manually open the gripper during the teaching process, the Grip_Open block must be called in the program. This program block contains the position verification logic from step S2. The operator must first confirm and input the current safe position coordinates to the program, and only after the program verifies and approves the coordinates can the operation proceed. This "confirm position before acting" mechanism replaces dangerous physical button operations with convenient, programmed operation.

[0034] S5: Modular packaging and encryption protection To prevent unauthorized personnel from modifying the safety logic on the production floor, this invention encapsulates the aforementioned control logic into reusable function modules and encrypts it using encryption tools provided by the robot manufacturer.

[0035] The advantages of this approach are: Tamper-proof: The protection logic is invisible and unalterable to ordinary users, ensuring the long-term effectiveness of the protection function. Easy to deploy: When debugging new projects or new equipment, simply import the encryption module and configure the target point coordinates to quickly deploy the anti-fall protection system, significantly shortening the debugging cycle.

[0036] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A safety control method for preventing industrial robots from falling due to misoperation, characterized in that, Includes the following steps: S1. By rewriting the underlying parameter file related to the gripper's action in the robot control system, the action signal of the gripper is prevented from being directly triggered by external physical buttons or interface shortcut keys, so that the action signal of the gripper can only be triggered and output through a preset control program. S2. When a gripper action command containing target coordinate X is received, the reference coordinate system F corresponding to the target coordinate X is obtained, and the actual coordinate Y of the robot under the reference coordinate system F is calculated. S3. Calculate the difference Z between the target coordinate X and the actual coordinate Y, and determine whether the difference Z is within the preset tolerance range N; S4. If the difference Z is within the tolerance range N, the verification passes and the control program is allowed to output the corresponding gripper action signal; if the difference Z exceeds the tolerance range N, the verification fails, the gripper action signal is intercepted and the program execution is terminated.

2. The safety control method according to claim 1, characterized in that, In step S1, the output attributes related to the release signal and / or disengagement signal in the robot system's underlying parameter file are modified to read-only mode to block the direct control permissions of the corresponding gripper control shortcut buttons on the robot teach pendant.

3. The safety control method according to claim 1, characterized in that, In step S2: The reference coordinate system F includes at least the tool coordinate system Toolx and the workpiece coordinate system Basex; The coordinates (X, Y) and the difference Z contain spatial position data and attitude data, specifically including: translation coordinate values ​​of the X-axis, Y-axis, and Z-axis, Euler angle rotation values ​​of A, B, and C, and coordinate values ​​of external axes E1, E2, and E3.

4. The safety control method according to claim 3, characterized in that, In step S3, the specific judgment logic for determining whether the difference Z is within the preset tolerance range N is as follows: Calculate the absolute value of each element (x, y, z, a, b, c, E1, E2, E3) in the difference Z; Compare the tolerance range N with the absolute value of each element; If and only if the following conditions are met: |Zx|≤N and |Zy|≤N and |Zz|≤N and |Za|≤N and |Zb|≤N and |Zc|≤N and |Z.E1|≤N and |Z.E2|≤N and |Z.E3|≤N, the difference Z is determined to be within the preset tolerance range N, and a verification pass signal is returned; otherwise, a verification fail signal is returned.

5. The safety control method according to any one of claims 1 to 4, characterized in that, It also includes step S5: Encapsulation and Encryption: The coordinate acquisition, position verification, and conditional execution logic in steps S2 to S4 are encapsulated into independent function blocks. The function block is called in the gripper release or release program segment of the robot control gripper; Encrypt the encapsulated function blocks to prevent unauthorized tampering.

6. The safety control method according to claim 1, characterized in that, The preset tolerance range N is 0.1 mm.

7. A safety control system for preventing industrial robots from falling due to misoperation, characterized in that, The system is applied to perform the security control method as described in any one of claims 1-6, the system comprising: Low-level permission restriction module: used to rewrite the low-level parameter file related to gripper action in the robot control system, prohibiting the direct triggering of gripper action signals through external physical buttons or interface shortcut keys, so that the action signals can only be triggered and output through the preset control program; Position acquisition module: When a gripper action command containing target coordinate X is received, the module acquires the reference coordinate system F corresponding to the target coordinate X and calculates the robot's actual coordinate Y in the reference coordinate system F. Position verification module: used to calculate the difference Z between the target coordinate X and the actual coordinate Y, and to determine whether the absolute values ​​of each parameter of the difference Z are all less than or equal to the preset tolerance range N; Action execution module: Used to respond to the judgment result of the position verification module. If the judgment is within the tolerance range N, the corresponding gripper action signal is output to control the gripper action; if the judgment is outside the tolerance range N, the signal is intercepted, the program is terminated and an alarm is triggered.

8. An industrial robot, characterized in that, include: Robotic arm and grippers or quick-change discs mounted at the end of the robotic arm; A controller, comprising a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the safety control method for preventing industrial robots from falling due to misoperation as described in any one of claims 1-6; The teach pendant is communicatively connected to the controller. The quick control button for directly forcing the output of gripper action signals has been removed from the interface of the teach pendant. Instead, an interactive interface that calls the preset gripper control program has been installed.

9. A computer-readable storage medium, characterized in that, It stores a computer program, which, when executed by a processor, implements the steps of the safety control method for preventing industrial robots from falling due to misoperation as described in any one of claims 1-6.

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