Robot collision detection control method and apparatus for performing same

Abstract

The present invention relates to a robot collision detection control method and an apparatus for performing same. The method comprises the steps of: calculating a risk level in case of a body collision by using a predicted force or a predicted pressure in the case of the collision with respect to an operation of a robot and a preset force limit value or a preset pressure limit value; and adjusting a collision detection threshold value for detecting the collision of the robot on the basis of the calculated risk level in the case of the body collision.

Description

Robot collision detection control method and device performing the same

[0001] The present invention relates to a method for setting a threshold for detecting a collision of a robot.

[0002] A robot is a machine that automatically processes or operates a given task using its own abilities. The application fields of robots can be classified into industrial, service, medical, space, and underwater.

[0003] Among them, an industrial robot is applied to industrial automation, and refers to a robot that is automatically controlled and reprogrammable, a multipurpose manipulator that can be programmed in three or more axes, and that can be fixed or moved, and may include hand-guided robots, manipulator parts of mobile robots, and collaborative robots.

[0004] Meanwhile, an industrial robot system can be configured, including an industrial robot as described above, an end device, and all machines, equipment, devices, additional axes, or sensors required for the robot to perform tasks.

[0005] Industrial robot systems are already widely used in machine-processing industries such as automobile manufacturing to perform repetitive movements equivalent to those performed by human arms, and their use has been increasing recently due to factors such as rising labor costs.

[0006] However, there are cases where death or serious injury occurs due to unintended contact with workers during the operation of industrial robots, and safety requirements for industrial robot systems and working environments are being established accordingly.

[0007] Additionally, to ensure the safety of industrial robot systems and their working environments, it is necessary to detect collisions between robots and stop their operations or generate warning signals.

[0008] The technical problem to be solved by the present invention is to provide a method for efficiently controlling collision detection of a robot to prevent physical damage, etc. caused by the operation of the robot, and a device for performing the same.

[0009] A robot collision detection control method according to an embodiment of the present invention for solving the above-described problem includes a step of calculating a risk level in case of a body collision using a predicted force or predicted pressure and a preset force limit value or pressure limit value for the operation of the robot; and a step of adjusting a collision detection threshold for detecting a collision of the robot based on the calculated risk level in case of a body collision.

[0010] The above robot is capable of power and force limiting (PFL) cooperative driving, and the collision detection threshold can be changed depending on the operation of the robot.

[0011] The above collision detection threshold can be adjusted to decrease as the calculated risk of body collision increases and to increase as the calculated risk of body collision decreases.

[0012] In the above threshold value adjustment step, the collision detection threshold value can be calculated based on the difference between the maximum torque value calculated using the preset force limit value or pressure limit value and the predicted torque value calculated by simulating the operation of the robot.

[0013] Additionally, if the difference between the torque value of the joint calculated according to the motion of the robot and the torque value measured at the joint exceeds the adjusted collision detection threshold, the motion of the robot may be stopped.

[0014] At least some of the above robot collision detection control methods can be implemented as a computer-readable recording medium recording a program for execution on a computer, and can be provided as a program itself.

[0015] Meanwhile, the robot collision detection control method can be performed by a robot according to an embodiment of the present invention.

[0016] A robot collision detection control device according to an embodiment of the present invention is a device for controlling collision detection of a robot capable of power and force limited (PFL) cooperative driving, comprising: a risk calculation unit for calculating a risk level in case of a body collision using a predicted force or predicted pressure and a preset force limit value or pressure limit value in case of a collision with respect to the operation of the robot; and a threshold adjustment unit for adjusting a collision detection threshold value for detecting a collision of the robot based on the calculated risk level in case of a body collision.

[0017] According to an embodiment of the present invention, by adjusting the collision detection threshold of the robot based on the risk of body collision calculated using the predicted force or predicted pressure and the preset force limit value or pressure limit value in case of a collision of the robot, the continuity of robot operation can be improved within a range that prevents death or serious injury from occurring due to unintentional contact with a worker during operation of the robot.

[0018] FIG. 1 is a perspective view showing the configuration of a robot according to one embodiment of the present invention.

[0019] Figure 2 is a table showing an example of allowable limits in power and force limit (PFL) driving mode.

[0020] Figure 3 is a drawing showing an example of a screen provided by a robot motion simulator.

[0021] Figure 4 is a block diagram showing the configuration of a robot motion simulation device according to one embodiment of the present invention.

[0022] FIG. 5 is a flowchart illustrating a method for setting collision information for robot motion simulation according to one embodiment of the present invention.

[0023] FIGS. 6 to 15 are drawings for explaining embodiments of a method for setting area information for a workspace of a robot.

[0024] Figures 16 to 23 are drawings for explaining embodiments of a method for setting tool information for a checkpoint for determining collision risk.

[0025] Fig. 24 is a block diagram showing the configuration of a robot collision detection control device according to one embodiment of the present invention.

[0026] Figure 25 is a flowchart showing a robot collision detection control method according to one embodiment of the present invention.

[0027] FIGS. 26 to 28 are drawings for explaining embodiments of a method for setting a collision detection threshold value of a robot.

[0028] The following merely exemplifies the principles of the present invention. Therefore, those skilled in the art will be able to implement the principles of the present invention and invent various devices within the scope and spirit of the present invention, even if not explicitly described or illustrated herein. Furthermore, all conditional terms and embodiments listed herein are expressly intended, in principle, to facilitate understanding of the present invention, and should be understood as being in no way limiting to the specifically enumerated embodiments and conditions.

[0029] Furthermore, all detailed descriptions of the principles, aspects, and embodiments of the present invention, as well as specific embodiments, should be understood to encompass structural and functional equivalents thereof. Furthermore, such equivalents should be understood to encompass not only currently known equivalents but also equivalents developed in the future, i.e., all devices invented to perform the same function, regardless of structure.

[0030] Thus, for example, the block diagrams herein should be understood as representing conceptual views of exemplary circuits embodying the principles of the present invention. Similarly, all flowcharts, state transition diagrams, pseudocode, and the like, which may be substantially represented on a computer-readable medium, should be understood as representing various processes performed by a computer or processor, regardless of whether a computer or processor is explicitly depicted.

[0031] The functions of various components depicted in the drawings, including functional blocks represented by processors or similar concepts, may be provided using dedicated hardware as well as hardware capable of executing software in conjunction with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, a single shared processor, or multiple individual processors, some of which may be shared.

[0032] Furthermore, any explicit use of terms such as processor, controller, or similar concepts should not be construed as exclusively referring to hardware capable of executing software, but should be understood to implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM), random access memory (RAM), and non-volatile memory for storing software. Other commonly used hardware may also be included.

[0033] In the claims of this specification, a component expressed as a means for performing a function described in the detailed description is intended to include any method for performing the function, including, for example, a combination of circuit elements performing the function, or any form of software including firmware / microcode, combined with appropriate circuitry for executing said software to perform the function. The invention defined by these claims should be understood to be equivalent to any means found in this specification for providing the functions provided by the various enumerated means, as long as they are combined and combined in the manner required by the claims.

[0034] The above-described purposes, features, and advantages will become more apparent through the following detailed description, taken in conjunction with the accompanying drawings. Accordingly, those skilled in the art will be able to readily implement the technical concepts of the present invention. Furthermore, in describing the present invention, detailed descriptions of known technologies related to the present invention will be omitted if they are deemed to unnecessarily obscure the gist of the invention.

[0035] Hereinafter, embodiments of the present invention will be described using a collaborative robot as an example, but the present invention is not limited thereto and can be applied to various robots including industrial robots.

[0036] A collaborative robot is a robot designed to interact directly with humans within a defined collaborative workspace, while collaborative operation can refer to the working state of a robot system and operator intentionally designed within a collaborative workspace.

[0037] Additionally, a collaborative workspace is a work area within a safeguarded space where robots and humans perform work simultaneously during production operations. It can mean an area within a work area where a robot system (including workpieces) and humans can perform work simultaneously during production operations.

[0038] FIG. 1 illustrates the configuration of a robot according to one embodiment of the present invention. The robot (100) may be configured to include a base (Base, 110), a plurality of joints (120 to 128), and a tool flange (Tool Flange, 150).

[0039] Referring to FIG. 1, the base (110) is a part for fixing the robot (100), and a cable connection connector between the robot (100) and the control box can be formed on the base (110).

[0040] The tool flange (150) is a part for mounting a gripper or tool on the robot (100), and input / output ports for controlling the gripper or tool and buttons for direct teaching can be arranged at locations adjacent to the tool flange (150).

[0041] Meanwhile, between the base (110) and the tool flange (150), a base joint (120), a shoulder joint (122), an elbow joint (124), a first wrist joint (126), a second wrist joint (127), and a third wrist joint (128) are provided, so that six-axis joint motions of the robot (100) can be possible.

[0042] A robot (100) having a structure as described with reference to FIG. 1 is capable of cooperative operation, and the cooperative operation may include one or more of the following methods: safe monitored stop, hand guiding, speed and position monitoring, and power and force limiting (PFL).

[0043] In the safety rated monitored stop method, the safety rated monitored stop function is used to stop the robot's motion before the operator enters the collaborative work area to interact with the robot system and complete a task.

[0044] If there is no driver in the collaborative work area, the robot (100) operates non-cooperatively. When the robot system is present in the collaborative work area, the safety rating monitoring function is activated and the robot's movement has stopped, allowing the driver to enter the collaborative work area. Meanwhile, after the driver exits the collaborative work area, the robot system's movement can resume without further intervention.

[0045] In the hand-guiding method, the operator uses a hand-operated device to transmit motion commands to the robot system, and the robot (100) must complete a safety-rated guard stop before the operator is permitted to enter the collaborative work area and perform the hand-guiding task.

[0046] This task is performed by manually operating guiding devices located at or near the robot's end-effector, and the robot system used for hand guiding must have additional features such as force output, virtual safety zones or tracking technology.

[0047] In the speed and position monitoring method, the robot system and the driver are allowed to move simultaneously in the collaborative work area, and risk reduction can be achieved by maintaining a minimum protective separation distance between the driver and the robot (100).

[0048] In this case, while the robot (100) is in operation, the distance between the robot system and the operator should never be closer than the protective separation distance, and the robot system stops when the separation distance decreases to a value smaller than the protective separation distance. Meanwhile, when the operator moves away from the robot system, the robot system can automatically resume operation while maintaining the minimum protective separation distance, and when the robot system slows down, the protective separation distance can be decreased simultaneously.

[0049] In driving modes with power and force limited (PFL) methods, physical contact between the robot system (including the workpiece) and the operator can occur intentionally or unintentionally, and power and force limited collaborative driving requires a robot system designed for this specific type of driving.

[0050] In this case, the risk can be reduced by managing the risk sources associated with the robot system below the allowable limit determined in the risk assessment process through a robot or safety-rated control system that includes fundamental safety measures, and the allowable limit can be set to the maximum allowable pressure and maximum allowable force that each human body part can withstand.

[0051] For example, the allowable limits in the power and force limited (PFL) driving mode may be set to the maximum allowable pressure and maximum allowable force per body part defined in the international standard (ISO TS 15066) as shown in Fig. 2, but the present invention is not limited thereto and may be changed depending on the level of risk to be managed.

[0052] Meanwhile, during collaborative driving using the power and force limitations (PFL) described above, contact between a body part of the collaborative robot and the operator may occur as a contact situation intended as part of the work process, an incidental contact situation resulting from non-compliance with the work sequence, or a failure type that causes a contact situation.

[0053] And the possible contact between the moving parts of the robot system and the human body can be divided into quasi-static contact and transient contact.

[0054] Quasi-static contact is contact between an operator and a robotic system component that occurs between a moving part of the robotic system and a fixed or moving part of another robot, where a part of the operator's body may become clamped, and the robotic system may apply pressure and force to the clamped part of the body for a significant period of time before the situation is relieved.

[0055] Meanwhile, dynamic contact is a contact between an operator and a robot system part that occurs where the operator's body part is not clamped to the moving part of the robot system, but can move away from or in a way that causes the operator to shrink, and the actual contact may be brief and can be defined by the inertia of the robot, the inertia of the body part, and the relative velocity of the two.

[0056] The risk of potential contact between a robot and a driver as described above can be reduced by considering how possible contact between the driver and the robotic system does not result in injury to the driver.

[0057] For example, risk can be reduced by identifying the conditions under which contact occurs, assessing the potential risk of contact, designing the robot system and workspace so that contact occurs less frequently or can be avoided, and applying risk reduction measures to keep contact situations below thresholds.

[0058] Here, for risk assessment, it must be assumed that the driver is not protected from potential contact by risk reduction measures such as personal protective equipment, and criteria such as the driver's exposed body parts, the initiation of the contact event, the probability or frequency of occurrence, the type of contact event, the contact area, speed, force, pressure, momentum, mechanical power, energy, and other quantitative items that can characterize the physical contact event may be considered.

[0059] Meanwhile, in order to reduce the risk assessed as above, a passive method related to the mechanical design of the robot system or an active method related to the control design of the robot system can be performed.

[0060] For example, passive safety design measures may include increasing the contact surface area, absorbing energy, extending energy transfer time or reducing impact force, or limiting moving mass.

[0061] Specifically, circular edges and corners, smooth surfaces or flexible surfaces may be used to increase the contact surface area, or fillers, cushioning materials, deformable components, complex joints or links may be used to absorb energy, extend energy transfer time or reduce impact force.

[0062] Active safety design measures may include, but are not limited to, limiting forces and torques, limiting the speed of moving parts, limiting momentum as a function of mass and speed, limiting mechanical power or energy, utilizing safety-rated flexible axes and space limitation functions, utilizing safety-rated monitored stop functions, utilizing detection to anticipate or recognize contact, etc.

[0063] Meanwhile, if the risk is not sufficiently reduced by a combination of passive or active risk reduction methods as described above, other risk reduction methods, including firewalls or safety devices, may be required.

[0064] As described above, the robot system is designed so that the risk to the operator is reduced below the threshold value by not exceeding the applicable threshold value for quasi-static contact and dynamic contact determined by the risk assessment.

[0065] A robot with cooperative driving capabilities in power and force limiting (PFL) mode may include the ability to set allowable thresholds for force, torque, speed, momentum, mechanical power, axis range, or spatial range.

[0066] For example, eliminating hazards associated with dynamic contact may include speed limits for moving parts (robots, work tools, workpieces, etc.) and appropriate design of physical characteristics such as the surface area of ​​the moving parts that come into contact with the operator.

[0067] Additionally, risk reduction associated with quasi-static contacts may include speed limits and physical characteristics similar to those for dynamic contacts, in addition to design characteristics of components of the robotic system that have the potential to grab or press on the operator or part of the operator's body.

[0068] In the above, a robot (100) and a robot system according to an embodiment of the present invention have been described with reference to FIGS. 1 and 2, but the present invention is not limited thereto, and the present invention can be applied to various robots based on international standards related to robots and robot systems (ISO 10218-1, ISO 10218-2, ISO TS 15066, ISO 12100, ISO 13850, ISO 13855, IEC 60204-1).

[0069] According to the present invention, in order to ensure safety for the robot system and the working environment, a robot operation simulation can be performed to simulate the operation of the robot (100) to check the possibility or risk of collision with a worker or surrounding objects.

[0070] For example, in the case of a robot having a cooperative driving function in power and force limitation (PFL) mode, if robot-related information, information about the tool to be mounted, information about check points for collision areas, and information about the robot's operation are input, information about the expected force and pressure in the event of a collision during the robot's operation can be calculated and displayed in the simulator.

[0071] Figure 3 illustrates an example of a screen provided by a robot motion simulator. Using information about the area where the robot is installed and information about the tool mounted on the robot, the predicted collision force and pressure during robot motion are calculated and displayed in graphs on the left side of the screen, and the corresponding robot motion can be sequentially displayed on the right side of the screen.

[0072] Meanwhile, the Pressure Force Index (PFI) indicating the risk of robot operation is calculated based on the predicted collision force and pressure as above, and the calculated risk PFI can be displayed together on the graph on the left side of the screen, and as shown in Fig. 3, when the PFI exceeds a limit value (e.g., 1), the risk assessment result can be displayed on the graph together with the corresponding operation of the robot.

[0073] Additionally, for the robot's operation in which the risk PFI exceeds the limit value as described above, the robot's operating speed (e.g., maximum operating speed) to reduce the PFI to below the limit value can be calculated and provided.

[0074] A simulator that performs the robot motion simulation as described above may be included in a robot or robot system and may store information related to the robot's motion in advance, or may exist outside the robot or robot system and receive information related to the robot's motion.

[0075] The robot motion simulator as described above may be implemented with software and / or hardware resources necessary to implement the technical idea of ​​the present invention, and does not necessarily mean a single physical component or a single device.

[0076] That is, the robot motion simulator may mean a logical combination of software and / or hardware provided to implement the technical idea of ​​the present invention, and, if necessary, may be implemented as a set of logical configurations for implementing the technical idea of ​​the present invention by installing them in devices spaced apart from each other and performing each function.

[0077] FIG. 4 is a block diagram illustrating the configuration of a robot motion simulation device according to an embodiment of the present invention. The illustrated robot motion simulation device (400) is a device for simulating the motion of a robot capable of power and force limitation (PFL) cooperative driving.

[0078] Referring to FIG. 4, the robot motion simulation device (400) can be configured to include an information acquisition module (410), a checkpoint setting module (420), and an information output module (430).

[0079] The information acquisition module (410) acquires robot installation information, risk area information, and collision-prone body part information for each risk area regarding the robot's workspace.

[0080] For example, the information acquisition module (410) can acquire an image of the robot's workspace, set the scale of the acquired image, and set the installation angle and installation position of the robot.

[0081] Here, one or more risk areas are set on the acquired image, and a body part with a high probability of collision can be set for each of the set risk areas.

[0082] The checkpoint setting module (420) sets a checkpoint for determining the risk of collision for the robot.

[0083] For example, the checkpoint setting module (420) can acquire an image of a tool mounted on a robot and set the checkpoint on the acquired image.

[0084] Here, the checkpoint setting module (420) can calculate the similarity between a plurality of representative shapes using information about the surrounding points of the checkpoint, and determine the shape of the checkpoint as one of the plurality of representative shapes based on the calculated similarity.

[0085] The information production module (430) produces coordinate information and shape information for the check point based on at least some of the acquired information and the set check point.

[0086] As used herein, the term "module" may refer to a functional and structural combination of hardware for implementing the technical concepts of the present invention and software for operating the hardware. For example, a module may refer to a logical unit of a given piece of code and the hardware resources required to execute that code. It does not necessarily refer to physically connected code or a single type of hardware.

[0087] According to the embodiment of the present invention as described above, by calculating coordinate information and shape information for checkpoints based on robot installation information, risk area information, and collision-prone body part information for each risk area set for the robot's workspace, and checkpoints for determining collision risk set for the robot and tool, it is possible to easily set collision information for simulating the operation of a robot capable of power and force limited (PFL) cooperative driving.

[0088] FIG. 5 is a flowchart illustrating a collision information setting method for robot motion simulation according to one embodiment of the present invention, and will be described as an example of what is performed by a robot motion simulation device (400) as described with reference to FIG. 4.

[0089] The simulation device (400) obtains robot installation information, risk area information, and collision-prone body part information for each risk area for the robot's workspace (step S500).

[0090] In step S500, an image of the robot's workspace can be acquired, a scale of the acquired image can be set, and at least one of the robot's installation angle and installation position can be set.

[0091] In addition, one or more risk areas are set on the acquired image, and for each of the set risk areas, a body part corresponding to at least one of the skull and forehead, face, neck, back and shoulder, chest, abdomen, pelvis, upper arms and elbow joints, lower arms and wrist joints, hands and fingers, thighs and knees, and lower legs can be set.

[0092] Referring to FIGS. 6 to 15, embodiments of a method for setting area information for a robot's workspace in step S500 will be described in more detail.

[0093] Referring to FIG. 6, a 2D image representing the workspace of the robot may be input, but the present invention is not limited thereto, and a 3D image representing the workspace of the robot in three dimensions may also be input.

[0094] Referring to FIG. 7, a workspace (710) of a robot may be displayed on a screen of a simulation device (400), and a user interface (720 to 728) for setting area information for the workspace (710) may be provided.

[0095] As shown in Fig. 8, the user can select the “Scaling line” button (720) on the screen of the simulation device (400) and then use the scaling bar (730) to set the actual size of the workspace (710) displayed on the screen.

[0096] Next, the user can input the angle at which the robot is installed in the “Orignin rotation ang” input field (721) as shown in FIG. 9, select the “Robot orignin” button (722) as shown in FIG. 10, and then use the cursor (732) to set the position at which the robot is installed on the screen.

[0097] Then, when the user selects a body part that may collide in the "Collision par" selection window (723) as shown in FIG. 11, and then selects the "Rectangle" button (724) as shown in FIG. 12 and sets a risk area (734), a body part (hand, HAND) that may collide in the risk area (734) is displayed together with the risk area (734) on the screen.

[0098] Additionally, as illustrated in FIGS. 12 and 13, the user can set the risk areas (735, 736) and the collision-prone body parts for each of the risk areas (735, 736) using the method described above.

[0099] As described above, when the area information setting for the robot's workspace (400) is completed, the user can select the "Save Area info" button (727) as shown in FIG. 15 to save the set area information.

[0100] The simulation device (400) sets a check point for determining the risk of collision for the robot (step S510), and, based on at least some of the information acquired in step S500 and the check point set in step S510, calculates coordinate information and shape information for the check point (step S520).

[0101] In step S510, an image of a tool mounted on a robot is acquired, and checkpoints can be set on the acquired image.

[0102] Meanwhile, checkpoints for determining the risk of collision can be set in the main body of the robot rather than in the tool, and checkpoint information for the main body of the robot can already be stored in the simulation device (400).

[0103] Referring to FIGS. 16 to 23, embodiments of a method for setting a check point and calculating coordinate information and shape information for the check point will be described in more detail.

[0104] Referring to FIG. 16, a 3D image representing a tool mounted on a robot may be input, but the present invention is not limited thereto, and may also be a 2D image obtained by photographing a tool mounted on a robot.

[0105] Referring to FIG. 17, a tool (810) mounted on a robot may be displayed on the screen of the simulation device (400), and a user interface (812 to 815, 821 to 829) for setting a check point for the tool (810) may be provided.

[0106] In step S520, shape information about the checkpoint can be derived using information about the surrounding points of the checkpoint.

[0107] For example, similarity between multiple representative shapes can be calculated using information about surrounding points of a checkpoint, and the shape of the checkpoint can be determined as one of the multiple representative shapes based on the calculated similarity.

[0108] Here, the plurality of representative shapes may include at least one of a half sphere, a corner, a cylinder, and a flat, but the present invention is not limited thereto.

[0109] Meanwhile, using the shape information produced as described above, a normal vector for the check point can be produced.

[0110] For example, when setting a check point for a tool having a shape as shown in (a) of Fig. 18, the user can select a desired check point on a 3D image as shown in (b) of Fig. 18.

[0111] In this case, points located around the checkpoint selected by the user are set, and information about the surrounding points (e.g., location and vector information, etc.) is used to fit each of a plurality of representative shapes, so that the similarity with the representative shape can be calculated.

[0112] As illustrated in (c) of Fig. 18, a representative shape having the highest similarity among a plurality of representative shapes is determined, and information on the determined representative shape can be stored as shape information for the check point.

[0113] Here, the representative shape may be a half sphere, and the radius of the hemisphere with the highest similarity can be obtained as shape information for the check point using information about the surrounding points of the check point.

[0114] As illustrated in FIG. 19, when a user selects a check point (830) on a 3D image of a tool displayed on the screen of a simulation device (400), check point identification information is entered into a check point identification window (826), the location of the check point is automatically entered into a “Collision point xyz” display window (827), and a perpendicular vector to the check point can be automatically entered into a “Normal vector xyz” display window (828).

[0115] Additionally, according to the check point shape information calculated as described above, the radius of a hemisphere similar to the check point can be automatically entered in the “Collision radius” display window (829).

[0116] And as shown in FIGS. 20 to 22, the user can additionally set check points (831, 832, 833) using the method described above, and each additional setting can produce the location, vertical vector, and shape information (radius) of each check point and be automatically input.

[0117] According to another embodiment of the present invention, while photographing an actual tool using a device such as a tablet PC, a check point can be selected directly on the image of the tool displayed on the screen.

[0118] Referring to FIG. 23, an image (910) of a tool being photographed is displayed on the screen (900) of a tablet PC, and when a user presses the "Add" button (920) and then touches a desired check point (911), location information (925) for the touched check point (911) can be displayed on the screen.

[0119] Additionally, on the screen (900) of the tablet PC illustrated in FIG. 23, the vertical vector and shape information for the check point (911) described above may be calculated and additionally displayed.

[0120] In the above, the collision information setting method for robot motion simulation according to one embodiment of the present invention was described as being performed by a robot motion simulation device, but the present invention is not limited thereto, and may be performed on a personal computer (PC), laptop, tablet, etc., may be performed on a teaching pendant, which is a teaching box provided in a robot system, or may be performed on a control station for controlling the robot or on the robot itself.

[0121] According to another embodiment of the present invention, by simulating the operation of the robot according to the collision information set as described above, and calculating and providing the risk level in case of collision of the robot for each operation, it is possible to prevent death or serious injury from occurring due to unintentional contact with a worker during the operation of the robot.

[0122] For example, when area information and checkpoint information are set for the workspace of the robot according to the collision information setting method described with reference to FIGS. 4 to 23, and position, vertical vector, and shape information for the checkpoint are calculated, the risk level in case of a body collision can be calculated for each movement according to the set and calculated information.

[0123] The risk level for each movement can be calculated using the Pressure Force Index (PFI) as shown in the mathematical formula 1 below.

[0124]

[0125] In mathematical expression 1, “f_est” is a force value that occurs during a collision predicted through simulation of robot movement, and can be calculated as in mathematical expression 2 below.

[0126]

[0127] In Equation 2, v rel is the relative velocity of the robot and the human, μ is the composite mass of the robot and the human, and k is the composite stiffness of the robot and the human.

[0128] In addition, in mathematical expression 1, “p_est” is a pressure value that occurs during a collision predicted through simulation of robot movement, and can be calculated as in mathematical expression 3 below.

[0129]

[0130] In mathematical expression 3, E * is the effective elastic modulus at the time of collision, and R Sis the contact radius at the time of collision.

[0131] And in mathematical expression 1, “f_max” is a force limit value for each human body part, and “p_max” is a pressure limit value for each human body part, and each may have values ​​as described with reference to FIG. 2, but the present invention is not limited thereto, and may be set to values ​​required by the standard.

[0132] As described above, when the PFI indicating the risk in case of a body collision is calculated, if the PFI value exceeds 100, the force or pressure predicted by the simulation in case of a collision goes beyond the range of the limit value, and if the checkpoint during the corresponding operation of the robot collides with a person, it can be judged to be dangerous enough to cause serious damage to the body.

[0133] Accordingly, for operations where the PFI value exceeds 100 as described above, a risk reduction method may be additionally provided to lower the PFI value to 100 or less.

[0134] For example, for an operation in which the risk of a body collision exceeds the standard, the operation speed required to reduce the risk to below the standard is calculated and applied, thereby reducing the risk of collision with a worker's body part during power and force limit (PFL) cooperative driving.

[0135] According to another embodiment of the present invention, by adjusting a collision detection threshold for detecting a collision of a robot based on the risk level of a body collision calculated as described above, the continuity of robot operation can be improved within a range that prevents death or serious injury from occurring due to unintentional contact with a worker during operation of the robot.

[0136] FIG. 24 is a block diagram illustrating the configuration of a robot collision detection control device according to an embodiment of the present invention. The illustrated robot collision detection control device (1000) may be configured to include a risk calculation unit (1010) and a threshold value adjustment unit (1020).

[0137] Descriptions of the configuration and operations of the robot collision detection control device (1000) illustrated in Fig. 24 that are identical to those described above with reference to Figs. 1 to 23 will be omitted.

[0138] Referring to FIG. 24, the risk calculation unit (1010) calculates the risk in case of a body collision using the predicted force or predicted pressure and the preset force limit value or pressure limit value for the robot's movement.

[0139] The threshold value adjustment unit (1020) adjusts the collision detection threshold for detecting collision of the robot based on the risk of body collision calculated by the risk calculation unit (1010).

[0140] For example, the risk calculation unit (1010) calculates the risk of body collision for each movement of the robot based on the speed, shape of the collision site, and body part that may collide according to the movement of the robot, and the threshold value adjustment unit (1020) can change the collision detection threshold for each movement of the robot based on the risk of body collision calculated for each movement.

[0141] Here, the collision detection threshold is used to detect collisions between the robot and surrounding objects. If a collision exceeding the collision detection threshold is detected, the robot is judged to have collided with the surrounding objects and the robot's movement may be stopped.

[0142] As the collision detection threshold is reduced, the robot's sensitivity to detect collisions can increase, and the robot's insensitivity to detect collisions can decrease.

[0143] Conversely, as the collision detection threshold increases, the robot's sensitivity to detect collisions may decrease, and the robot's insensitivity to detect collisions may increase.

[0144] The threshold value adjustment unit (1020) can adjust the collision detection threshold value to decrease as the risk of a body collision calculated by the risk calculation unit (1010) increases, and can adjust the collision detection threshold value to increase as the risk of a body collision decreases.

[0145] For this purpose, the threshold value adjustment unit (1020) can calculate and adjust the collision detection threshold value based on the difference between the maximum torque value calculated using a preset force limit value or pressure limit value and the predicted torque value calculated by simulating the motion of the robot.

[0146] The robot collision detection control device (1000) as described above is for controlling collision detection of a robot capable of power and force limitation (PFL) cooperative driving, and may be built into the robot or implemented as a separate device external to the robot.

[0147] A robot according to an embodiment of the present invention has a collision detection function to prevent danger to humans, and can stop operation and generate a warning signal when a collision is detected.

[0148] The collision detection function as described above can determine that a collision has occurred in the robot when a collision exceeding a collision detection threshold is detected.

[0149] For example, as in the mathematical expression 4 below, the torque value (τ) of the joint calculated according to the robot's movement req ) and the torque value measured at the joint (τ mea ) is the collision detection threshold (τ th ) is exceeded, a collision detection of the robot may occur and the robot's movement may be stopped.

[0150]

[0151] In mathematical expression 4, the torque value of the joint (τ req ) is the calculated value of the torque required at each joint according to the posture of the robot manipulator, and the torque value (τ) measured at the joint mea ) is the torque value measured at each joint of the corresponding posture, and the collision detection threshold (τ th ) may be a threshold of torque that serves as a criterion for collision detection.

[0152] Accordingly, for the robot's motion, the torque calculation value of the joint (τ req ) and measured values ​​(τ mea ) is the collision detection threshold (τ th ) is greater than, collision detection of the robot may occur.

[0153] Collision detection threshold (τ th ) is set lower, the higher the collision detection sensitivity (collision detection insensitivity is lower), so that collision detection may occur even with small impacts, which may cause the robot to stop moving frequently.

[0154] Conversely, the collision detection threshold (τ th ) is set higher, the collision detection sensitivity decreases (collision detection insensitivity increases), so that even if a collision occurs with a worker, collision detection may not occur and the robot may continue to operate.

[0155] Meanwhile, when a collision is detected as described above, the robot may immediately pause its trajectory movement, or move slightly in a direction to avoid an external force and then pause its trajectory movement. After being paused, the robot may remain stopped until a predetermined motion resumption input is received from the operator.

[0156] Additionally, when a collision is detected, the robot's motion program and threads are paused, and the program may be terminated at the operator's option.

[0157] Figure 25 is a flowchart illustrating a robot collision detection control method according to one embodiment of the present invention.

[0158] Referring to Fig. 25, for the robot's motion, the risk level in case of a body collision is calculated using the predicted force or predicted pressure and the preset force limit value or pressure limit value in case of a collision (step S1100).

[0159] Afterwards, based on the risk level of body collision calculated in step S1100, the collision detection threshold for detecting collision of the robot is adjusted (step S1110).

[0160] A robot to which the collision detection control method described above is applied is a robot capable of power and force limiting (PFL) cooperative driving, and may have a protective stop function and a separate emergency stop function to stop operation when a collision is detected.

[0161] At step S1100, the risk of body collision can be calculated for each robot movement based on the speed, shape of the collision site, and body part that may collide according to the robot's movement.

[0162] Here, if the risk level in case of a body collision exceeds the standard value, the speed of the robot's corresponding movement can be adjusted so that the risk level in case of a body collision is controlled to be below the standard value.

[0163] Meanwhile, the risk level in case of a body collision can be calculated as the PFI (Pressure Force Index) as described above, but the present invention is not limited thereto, and can be calculated as a value indicating the risk or safety level that may be inflicted on a worker when a body part that can be collided in a specific movement of the robot is collided.

[0164] In this case, at step S1110, the collision detection threshold may change depending on the robot's motion as the robot moves.

[0165] That is, for each movement of the robot, the risk of body collision is calculated and the collision detection threshold is adjusted, so that the collision detection threshold can change in real time as the robot moves.

[0166] As another example, the collision detection threshold may be adjusted over a period of time, for a segment of a series of actions, or for the entire action program.

[0167] Meanwhile, the collision detection threshold can be adjusted to decrease as the risk of a body collision increases and to increase as the risk of a body collision decreases.

[0168] For example, the maximum torque value (τ) calculated using a preset force limit value or pressure limit value, as in the mathematical expression 5 below max ) and the predicted torque value (τ') calculated by simulating the robot's movements. est ), a new collision detection threshold (τ') is developed based on the difference between th ) can be produced.

[0169]

[0170] In mathematical expression 5, the maximum torque value (τ max ) can be calculated using the maximum allowable pressure or maximum allowable force for each body part defined in the international standard (ISO TS 15066) as shown in Fig. 2, but the present invention is not limited thereto.

[0171] And the predicted torque value (τ' est ) is the torque value estimated by simulating the robot's movement, and the maximum torque value (τ max ) in the predicted torque value (τ') est ) is the collision detection threshold (τ') th ) can be determined.

[0172] That is, the predicted torque value (τ') is estimated by simulating the robot's motion. est), based on the maximum torque value (τ max ) is larger, the collision detection threshold (τ') is increased accordingly. th ) can be adjusted to make the robot more insensitive to collision detection, and the maximum torque value (τ max ) is smaller, the collision detection threshold (τ') is smaller. th ) can be adjusted to make the robot more sensitive to collision detection.

[0173] More specifically, the maximum torque value (τ max ), the maximum allowable force (F ) set according to the collision-prone body part is calculated as in Equation 6 below. max ) and maximum allowable pressure (P max ) according to the maximum allowable force (f(P) max )) is the maximum allowable force (f') max ) can be obtained.

[0174] Here, the maximum allowable force (F max ) and maximum allowable pressure (P max ) can have force limit values ​​and pressure limit values ​​for each body part as shown in Fig. 2.

[0175]

[0176] Meanwhile, the maximum allowable pressure (P) set according to the body part that can be collided max ) according to the second maximum allowable force (f(P max )) can be calculated as in mathematical equation 7 below, assuming contact between spheres.

[0177]

[0178] And using the mathematical expression 8 below, the maximum allowable force (f') obtained as mentioned above max ) from the maximum torque value (τ max ) can be produced.

[0179]

[0180] In mathematical expression 8, J T is the transpose of the Jacobian matrix used for transformation from the space of linear motion to the space of rotational motion, and is the maximum torque value (τ max ) is the maximum allowable force (f') max ) can be obtained by multiplying the transpose matrix of the Jacobian matrix representing the kinematic characteristics of the robot.

[0181] And the predicted torque value (τ' est ), the force (F) generated during a collision is predicted through simulation of robot motion, as shown in mathematical expression 9 below. est ) can be obtained.

[0182]

[0183] In Equation 9, v rel is the relative velocity of the robot and the human, μ is the composite mass of the robot and the human, and k is the composite stiffness of the robot and the human.

[0184] And as shown in the mathematical expression 10 below, the predicted power (f est ) in the transpose matrix of the Jacobian matrix (J T ) is multiplied to obtain the predicted torque value (τ') est ) can be obtained.

[0185]

[0186] Accordingly, a new collision detection threshold (τ' th ) can be calculated as shown in mathematical formula 11 below.

[0187]

[0188] As mentioned above, the collision detection threshold is a new collision detection threshold (τ' th ), the torque value (τ') of the joint calculated according to the robot's movement as in the mathematical expression 12 below req ) and the torque value (τ) measured at the corresponding joint mea ) is the adjusted collision detection threshold (τ').th ) is exceeded, collision detection may occur and the robot's movement may stop.

[0189]

[0190] Hereinafter, with reference to FIGS. 26 to 28, embodiments of a method for setting a collision detection threshold of a robot will be described.

[0191] Referring to FIG. 26, an interface (1200) for setting a collision detection threshold may be provided via a robot or robot collision detection control device (1000).

[0192] The collision detection threshold can be expressed as a desensitivity, and the collision detection threshold can be adjusted in proportion to the desensitivity that is set.

[0193] Meanwhile, if the user does not select manual or automatic settings, the collision detection insensitivity may be set to a preset initial value (e.g., 50%).

[0194] If the user selects manual setting, the user can directly adjust the collision detection insensitivity by moving the icon (1210) displayed on the interface (1200), as shown in FIG. 27.

[0195] And, as shown in Fig. 28, when the user selects automatic setting, the robot collision detection control method according to the embodiment of the present invention as described above is performed, so that the collision detection insensitivity can be automatically adjusted according to the risk level in case of a body collision.

[0196] The robot collision detection control method as described above can be performed by a robot according to an embodiment of the present invention, but the present invention is not limited thereto, and can also be performed through a separate control device.

[0197] The methods according to the present invention described above can be produced as a program to be executed on a computer and stored in a computer-readable recording medium. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc.

[0198] Computer-readable recording media can be distributed across network-connected computer systems, allowing computer-readable code to be stored and executed in a distributed manner. Furthermore, functional programs, codes, and code segments for implementing the above method can be readily inferred by programmers skilled in the art to which the present invention pertains.

[0199] Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. Furthermore, such modifications should not be understood individually from the technical idea or prospect of the present invention.

Claims

In a method for controlling collision detection of a robot, A step of calculating the risk level in case of a body collision using the predicted force or predicted pressure and the preset force limit value or pressure limit value in case of collision with respect to the operation of the above robot; and A robot collision detection control method, characterized in that it comprises a step of adjusting a collision detection threshold for detecting a collision of the robot based on the calculated risk level in case of a body collision. In the first paragraph, A robot collision detection control method characterized in that the above robot is capable of power and force limiting (PFL) cooperative driving. In the first paragraph, the risk calculation step A robot collision detection control method, characterized by comprising a step of calculating the risk level in case of a body collision for each movement of the robot based on the speed, shape of the collision site, and collision-prone body part according to the movement of the robot. In the third paragraph, A robot collision detection control method characterized in that the collision detection threshold can be changed according to the operation of the robot as the robot moves. In the first paragraph, the collision detection threshold is A robot collision detection control method characterized in that the calculated risk of body collision is adjusted to decrease as the calculated risk of body collision increases, and to increase as the calculated risk of body collision decreases. In the first paragraph, the threshold value adjustment step A robot collision detection control method, characterized in that it comprises a step of calculating the collision detection threshold value based on the difference between the maximum torque value calculated using the preset force limit value or pressure limit value and the predicted torque value calculated by simulating the operation of the robot. In the first paragraph, A robot collision detection control method, characterized in that it further includes a step of stopping the operation of the robot when the difference between the torque value of the joint calculated according to the operation of the robot and the torque value measured at the joint exceeds the adjusted collision detection threshold value. In the first paragraph, A robot collision detection control method, characterized in that it further includes a step of adjusting the operating speed of the robot when the calculated risk level in case of a body collision exceeds a standard value. A computer program stored on a computer-readable recording medium for executing any one of the methods of claims 1 to 8 in combination with hardware. A robot performing any one of the methods of claims 1 to 8. In a device for controlling collision detection of a robot capable of power and force limitation (PFL) cooperative driving, Regarding the operation of the above robot, a risk calculation unit that calculates the risk in case of a body collision using the predicted force or predicted pressure and the preset force limit value or pressure limit value in case of a collision; and A robot collision detection control device characterized by including a threshold adjustment unit that adjusts a collision detection threshold for detecting a collision of the robot based on the calculated risk level in case of a body collision. In the 11th paragraph, the risk calculation unit Based on the speed, collision site shape, and collision-prone body part according to the robot's movement, the risk level in case of a body collision is calculated for each movement of the robot, A robot collision detection control device characterized in that the collision detection threshold can be changed for each movement of the robot according to the calculated risk level in case of a body collision. In the 11th paragraph, the collision detection threshold is A robot collision detection control device characterized in that it is adjusted so that the calculated risk of body collision increases as it decreases, and increases as the calculated risk of body collision decreases. In the 11th paragraph, the threshold value adjustment unit A robot collision detection control device characterized in that the collision detection threshold is calculated based on the difference between the maximum torque value calculated using the preset force limit value or pressure limit value and the predicted torque value calculated by simulating the operation of the robot.

Images