Seven-degree-of-freedom mechanical arm obstacle avoidance path planning method in limited space and related device

Abstract

The invention provides a seven-degree-of-freedom mechanical arm obstacle avoidance path planning method in a limited space and a related device, and relates to the field of robot control. Wherein the electronic equipment simplifies an obstacle in a working space of the mechanical arm into a simplified graph wrapping the obstacle; a plurality of tail end poses of the mechanical arm are obtained; then, for each tail end pose, according to an inverse kinematics solution corresponding to the tail end pose, determining a shoulder-elbow connecting line and an elbow-wrist connecting line corresponding to the inverse kinematics solution; wherein the shoulder-elbow connecting line represents a connecting line between the shoulder part and the elbow part of the mechanical arm, and the elbow-wrist connecting line represents a connecting line between the elbow part and the wrist part of the mechanical arm. And finally, collision detection is conducted on the simplified graph, the shoulder-elbow connecting line and the elbow-wrist connecting line, and the arm angle range of the mechanical arm for avoiding the obstacle is obtained. In this way, the obstacle is simplified, the collision detection efficiency is improved, and therefore the feasible arm angle range of the mechanical arm can be rapidly obtained.

Description

Technical Field

[0001] The present application relates to the field of robot control, and more specifically, to a method and related device for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space. Background Art

[0002] Compared with the six-DOF robot arm, the seven-DOF robot arm has higher flexibility and is therefore widely used in human-machine collaboration, medical and aerospace fields. When performing tasks in Cartesian space, the redundant degrees of freedom of the seven-DOF robot arm give it unique self-motion characteristics. However, the path planning of the seven-DOF robot arm still mostly follows the method of the six-DOF robot arm, mainly focusing on joint space planning.

[0003] However, the seven-DOF manipulator has a unique local self-motion characteristic, and its elbow can move in a circle around the straight line formed by the shoulder and wrist while keeping the end position unchanged. However, most current path planning methods are limited to the joint space, and the generated path is usually unique and difficult to further optimize. This has led to the failure to effectively utilize the self-motion characteristics of the seven-DOF manipulator, thus limiting its potential advantages in tasks such as obstacle avoidance. Therefore, how to efficiently determine the arm angle range of the seven-DOF manipulator to fully utilize its self-motion characteristics has become an urgent problem to be solved. Summary of the invention

[0004] In order to overcome at least one of the deficiencies in the prior art, the present application provides a seven-degree-of-freedom robot arm obstacle avoidance path planning method and related devices in a confined space, specifically including: In a first aspect, the present application provides a method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space, the method comprising: Simplifying obstacles in the working space of the robot arm into simplified graphics that enclose the obstacles; Acquire multiple end positions of the robotic arm; For each of the terminal postures, according to the inverse kinematics solution corresponding to the terminal posture, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematics solution, wherein the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the manipulator, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the manipulator; The simplified graph is subjected to collision detection with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robotic arm to avoid the obstacle.

[0005] In a second aspect, the present application further provides a seven-degree-of-freedom robot arm obstacle avoidance path planning device in a confined space, the device comprising: An object simplification module, used to simplify obstacles in the working space of the robot arm into simplified graphics that wrap the obstacles; An end position module, used to obtain multiple end positions of the robotic arm; An arm angle range module, for determining, for each of the end postures, a shoulder-elbow connection line and an elbow-wrist connection line corresponding to the inverse kinematics solution corresponding to the end posture, wherein the shoulder-elbow connection line represents a connection line between the shoulder and the elbow of the manipulator, and the elbow-wrist connection line represents a connection line between the elbow and the wrist of the manipulator; The arm angle range module is also used to perform collision detection on the simplified graph with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robotic arm to avoid the obstacle.

[0006] In a third aspect, the present application also provides a storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the seven-degree-of-freedom robotic arm obstacle avoidance path planning method in a confined space.

[0007] In a fourth aspect, the present application also provides an electronic device, comprising a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it implements any one of the methods for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space.

[0008] Compared with the prior art, this application has the following beneficial effects: The present application provides a seven-degree-of-freedom robot obstacle avoidance path planning method and related devices in a confined space. Among them, the electronic device simplifies the obstacles in the robot's working space into a simplified graphic that wraps the obstacles; and obtains multiple end postures of the robot; then, for each end posture, according to the inverse kinematics solution corresponding to the end posture, the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematics solution are determined; wherein the shoulder-elbow connection line represents the connection between the shoulder and elbow of the robot, and the elbow-wrist connection line represents the connection between the elbow and wrist of the robot. Finally, the simplified graphic is subjected to collision detection with the shoulder-elbow connection line and the elbow-wrist connection line to obtain the arm angle range for the robot to avoid obstacles.

[0009] In this way, the efficiency of collision detection is improved by simplifying the obstacles, so that the feasible arm angle range of the robot arm can be quickly obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1A flow chart of a method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space provided in an embodiment of the present application; Figure 2A A schematic diagram of a cube provided for an embodiment of the present application; Figure 2B A schematic diagram of a first simplified diagram provided in an embodiment of the present application; Figure 2C A schematic diagram of the dimensions of a first simplified graphic provided in an embodiment of the present application; Figure 3A A schematic diagram of a cylinder provided in an embodiment of the present application; Figure 3B A schematic diagram of a second simplified diagram provided in an embodiment of the present application; Figure 3C A schematic diagram of the dimensions of a second simplified graphic provided in an embodiment of the present application; Figure 4 A schematic diagram of the principle of the node to be evaluated provided in the embodiment of the present application; Figure 5 A schematic diagram of the arm angle of the robotic arm provided in an embodiment of the present application; Figure 6 A schematic diagram of a technical effect verification scenario provided by an embodiment of the present application; Figure 7 A technical effect verification conclusion diagram provided for the embodiments of the present application; Figure 8 A schematic diagram of the structure of a seven-degree-of-freedom robot arm obstacle avoidance path planning device in a confined space provided in an embodiment of the present application; Fig. 9 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0013] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0014] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0015] In the description of the present application, it should be noted that the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In addition, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0016] Based on the above statement, as introduced in the background technology, most of the current path planning methods are limited to the joint space, and the generated path is usually unique and difficult to further optimize. This leads to the failure to effectively utilize the self-motion characteristics of the seven-degree-of-freedom manipulator, thereby limiting its potential advantages in tasks such as obstacle avoidance. Therefore, how to efficiently determine the arm angle range of the seven-degree-of-freedom manipulator to fully utilize its self-motion characteristics has become an urgent problem to be solved.

[0017] Based on the discovery of the above technical problems, the inventors have proposed the following technical solutions to solve or improve the above problems through creative work. It should be noted that the defects in the solutions in the above prior art are the results obtained by the inventors after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed in the embodiments of the present application for the above problems below should all be the contributions made by the inventors to the present application in the process of invention and creation, and should not be understood as technical contents known to those skilled in the art.

[0018] In view of the discovery of the above problems, an embodiment of the present application (hereinafter referred to as the present embodiment) provides a method for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space. Figure 1 As shown, the method includes: S1,simplifies the obstacles in the robot's working space into a simplified graph that wraps the obstacles.

[0019] S2, obtain multiple end positions of the robot arm.

[0020] S3, for each end position, according to the inverse kinematics solution corresponding to the end position, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematics solution.

[0021] Among them, the shoulder-elbow line represents the line between the shoulder and elbow of the robot arm, and the elbow-wrist line represents the line between the elbow and wrist of the robot arm.

[0022] S4, performing collision detection on the simplified graph, the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range for the robot arm to avoid obstacles.

[0023] In this way, the efficiency of collision detection is improved by simplifying the obstacles, so that the feasible arm angle range of the robot arm can be quickly obtained. In this embodiment, the electronic device implementing the seven-degree-of-freedom robot obstacle avoidance path planning method in a confined space can be, but is not limited to, a robot controller, or a host computer that is communicatively connected to the robot controller. The host computer can be, but is not limited to, a tablet computer, a laptop computer, a desktop computer, etc.

[0024] To make the solution provided by this embodiment clearer, the host computer is used as an electronic device to implement the seven-degree-of-freedom robot arm obstacle avoidance path planning method in a confined space. Figure 1 Each step in the method shown in the flowchart is described in detail. However, it should be understood that the operations of the flowchart may not be implemented in order, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art may add one or more other operations to the flowchart, or remove one or more operations from the flowchart under the guidance of the content of this application. Figure 1 As shown, the method includes: S1,simplifies the obstacles in the robot's working space into a simplified graph that wraps the obstacles.

[0025] In this regard, this embodiment provides a plurality of candidate shapes for matching with the shape of the obstacle, and selects the target shape with the closest shape from them to simplify the obstacle. Therefore, as an optional implementation provided by this embodiment, step S1 may include: S1-1, according to the shape of the obstacle, determining a target shape that is closest to the shape of the obstacle from multiple candidate shapes.

[0026] S1-2, generating a basic graphic that wraps the obstacle according to the target shape, wherein the shape of the basic graphic is consistent with the target shape.

[0027] S1-3, expand the basic graph into a simplified graph.

[0028] The shape of the basic figure is a cube, a cylinder or a sphere, and the simplified figure is a first simplified figure, a second simplified figure or a third simplified figure. At this time, step S1-3 may include: S1-3-1A, if the shape of the basic figure is a cube, the basic figure is expanded to a first size in a direction away from the center position to obtain a first simplified figure.

[0029] The edges of the basic figure expand into 1 / 4 of a cylinder with the first size as the radius, and the vertices of the basic figure expand into 1 / 8 of a sphere with the first size as the radius.

[0030] For example, see Figure 2A The basic figure shown is a cube; after expansion, it is obtained as follows Figure 2B The first simplified figure is shown. It is not difficult to see that each edge of the basic figure expands into 1 / 4 of a cylinder with the first size as the radius, and the vertex of the basic figure expands into 1 / 8 of a sphere with the first size as the radius. Figure 2C Shows Figure 2A The size relationship of the basic figure before and after expansion is shown, where: They are the basic graphics before expansion. The minimum and maximum values ​​in the axis direction, are the minimum and maximum values ​​of the first simplified figure after expansion in the X, Y and Z directions respectively.

[0031] S1-3-1B, if the shape of the basic figure is a cylinder, the basic figure is expanded by a second dimension in a direction away from the axis to obtain an expanded cylinder; and half spheres are generated at both ends of the expanded cylinder to obtain a second simplified figure.

[0032] For example, see Figure 3A The basic shape shown is a cylinder with a radius of After expansion, we get Figure 3B The second simplified figure shown. Assume that the base figure expands the second dimension away from the axis , and obtain the expanded cylinder; and generate half spheres at both ends of the expanded cylinder, the radius of the sphere is . Figure 3C Shows Figure 3A The size relationship of the basic figure before and after expansion is shown. Figure 3A The base radius of the basic figure shown is The length of the central axis is The intersection points of the central axis and the upper and lower surfaces are and ,point is a point in the working space, and is parallel to the central axis. The foot of .

[0033] S1-3-1C, if the shape of the basic figure is a sphere, the basic figure is expanded by a third dimension in a direction away from the center of the sphere to obtain a third simplified figure.

[0034] For example, assuming that the base shape is a radius The third dimension of the sphere is , then the radius of the third simplified figure is .

[0035] In this way, the obstacles in the working space can be simplified into one of the first simplified graph, the second simplified graph and the third simplified graph, so as to facilitate subsequent collision detection.

[0036] Based on the above implementation, the simplified graphics of the wrapped obstacle are introduced. Figure 1 , the method further comprises: S2, obtain multiple end positions of the robot arm.

[0037] Each end position includes a path point and a posture. The path point represents the three-dimensional coordinates of the end of the robot in Cartesian space; the posture represents the rotation state of the end of the robot in the operating space, which is usually described by mathematical tools such as rotation matrix, Euler angle or quaternion. These parameters define the direction of the end effector relative to the reference coordinate system, ensuring that the robot can maintain the correct direction and angle when performing precise operations.

[0038] For multiple path points at the end of the robot arm, currently mature algorithms can be used for planning. For example, the sampling-based RRT (Rapidly-exploring Random Trees) algorithm, PRM (Probabilistic Roadmap Method) algorithm, genetic algorithm, etc. These algorithms can generate a collision-free path based on the structural characteristics and workspace limitations of the robot arm, ensuring that the robot arm moves safely and effectively from the initial position to the target position. In this embodiment, step S2 can plan the path of the end of the robot arm through a derivative algorithm of RRT. As an optional implementation method, step S2 includes: S2-1, generate random nodes.

[0039] For example, assume that a random node is represented as , then the coordinates of the random node can be calculated by the expression:

[0040] In the formula, The robot arm working space is The minimum and maximum values ​​in the axis direction, yes This example is only an optional implementation provided by this embodiment, and of course other methods can be selected to obtain random nodes located in the working space.

[0041] Based on the introduction of random nodes in the above embodiment, Figure 1 Step S1 in the embodiment further comprises: S2-2, determine the target node closest to the random node from the historical point set.

[0042] The historical point set includes the path exploration points generated for the end of the robot arm. Figure 4 As shown in the figure, multiple path exploration points 11 in the historical point set are shown, including the starting point of the end of the robot arm and the end point of the robot arm. The multiple path exploration points 11 are connected to form a random tree of the end exploration path. In this embodiment, the starting point is represented as , and the end point is represented as , the generated random nodes are represented as As can be seen from the figure, the distance The nearest path exploration point 11 is used as the target node, which is expressed as .

[0043] Based on the introduction of the target node in the above embodiment, Figure 1 Step S1 in the embodiment further comprises: S2-3, determine the node to be evaluated based on the target node, the end point of the robot arm and the random node.

[0044] For example, see Figure 4 For the target node, random node and end point in the graph, the coordinates of the three points are calculated as follows to obtain the node to be evaluated. The node table to be evaluated is represented as :

[0045] In the formula, and represents the preset weight, Indicates the preset growth step size.

[0046] S2-4, determine whether the line between the target node and the node to be evaluated collides with an obstacle. If so, return to step S2-1; if so, execute S2-5.

[0047] Among them, when judging whether the line between the target node and the node to be evaluated does not collide with the obstacle, the currently mature collision detection algorithm can be adopted. However, it is found in practice that the current collision detection algorithm is inefficient, especially when the shape of the obstacle is not constant, and a large amount of computing resources are required. In this embodiment, in order to improve the efficiency of collision detection, the obstacle is simplified into a simplified graphic that wraps the obstacle, and an efficient collision detection algorithm that matches the shape of the simplified graphic is used to detect whether the line between the target node and the node to be evaluated collides with the obstacle. Among them, the same collision detection algorithm is adopted to judge whether the line between the target node and the node to be evaluated collides with the obstacle and to judge whether the simplified graphic collides with the shoulder-elbow line and the elbow-wrist line.

[0048] S2-5, determine whether the node to be evaluated is within the preset range of the end point. If not, execute step S2-6. Otherwise, execute S2-7.

[0049] S2-6, adding the node to be evaluated to the historical point set. Then, returning to step S2-1.

[0050] S2-7, traverse a plurality of path points that can connect from the starting point to the end point of the robot arm from the historical point set, and obtain a plurality of end position poses according to the plurality of path points.

[0051] In this way, after multiple rounds of iterations through the above implementation, multiple path points that can connect from the starting point to the end point of the robot arm can be iterated; then, according to the posture of the end of the robot arm at the starting point and the end point, the posture of each path point can be obtained by interpolation.

[0052] For example, since the multiple path points in the Cartesian space obtained by the above implementation only contain position information, it is also necessary to assign corresponding posture information to each path point. In this example, according to the posture constraints of the starting point and the end point of the end of the robot arm, the posture of the intermediate point is obtained by linear Euler interpolation. The expression of linear Euler interpolation is:

[0053] In the formula, is the Euler angle of the starting point of the end of the robot arm, is the Euler angle of the end point of the robot arm, for The value between .

[0054] Based on the introduction of the terminal posture in the above embodiment, continue to refer to Figure 1 , the method further comprises: S3, for each end position, according to the inverse kinematics solution corresponding to the end position, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematics solution.

[0055] Among them, the shoulder-elbow line represents the line between the shoulder and elbow of the robot arm, and the elbow-wrist line represents the line between the elbow and wrist of the robot arm. Figure 5 The figure shows a seven-DOF manipulator of SRS configuration. The shoulder and wrist of the manipulator are composed of three intersecting axis revolute pairs, which can be regarded as a ball joint. The elbow is composed of a revolute pair. The connecting rods SE and EW can rotate around the straight line SW. Point E v is the starting reference position of connecting rods SE and EW. When connecting rods SE and EW rotate to point E, E v The angle between O and EO is defined as the arm angle ψ The arm angle is used to represent the redundant degrees of freedom of the seven-degree-of-freedom robot. When the tool at the end of the robot arm maintains its original posture, the control arm angle ψ The size of can control the robot's links SE and EW to avoid obstacles in Cartesian space.

[0056] It should be understood that, in Cartesian space, after obtaining a collision-free path from the start point to the end point containing position and posture information, each joint angle can be obtained by inversely solving the position and posture of the end of the robot arm given the arm angle value. Among them, the inverse kinematics solution of the robot arm is a mature technology in the field of robot control, and this embodiment will not be repeated.

[0057] Based on the introduction of the shoulder-elbow connection line and the elbow-wrist connection line in the above embodiment, continue to refer to Figure 1 , the method further comprises: S4, performing collision detection on the simplified graph, the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range for the robot arm to avoid obstacles.

[0058] Since the obstacle is simplified as follows in this embodiment Figure 2B The first simplified diagram shown and Figure 3B The second simplified graph is shown, and efficient collision detection algorithms are provided for these simplified graphs. These collision detection algorithms are described in detail below.

[0059] for Figure 2B The first simplified graph shown can be used to detect whether an obstacle collides with the shoulder-elbow line and the elbow-wrist line by the following judgment method: For any discrete point on the shoulder-elbow line and the elbow-wrist line , if the coordinates of the discrete points satisfy: , , , , or

[0060] In the formula, Indicates that the first simplified graph is The minimum and maximum values ​​in the axis direction; if the conditions in the above expression are met, it means that the discrete point is outside the bounding box of the first simplified figure. Therefore, it can be determined that the discrete point will not collide with the first simplified figure.

[0061] If the coordinates of the discrete points satisfy:

[0062] In the formula, Indicates that the corresponding basic graphics are The minimum and maximum values ​​in the axis direction; if the conditions in the above expression are met, it means that the discrete point is located inside the basic figure, so it can be determined that the discrete point will collide with the first simplified figure.

[0063] If the discrete point is located in the bounding box of any 1 / 4 cylinder, and the distance between the discrete point and the edge of the corresponding basic figure of the 1 / 4 cylinder is greater than the first size, it is determined that the discrete point will not collide with the first simplified figure.

[0064] For example, Figure 2C As shown, taking the 1 / 4 cylinder shown in the upper left corner of the figure as an example, assuming that the 1 / 4 cylinder shown in the upper left corner is The minimum and maximum values ​​in the axis direction are , then the cubic area formed by these minimum and maximum values ​​is the bounding box of the 1 / 4 cylinder. If the coordinates of the discrete points satisfy:

[0065]

[0066] It can be determined that the discrete point is within the bounding box of the 1 / 4 cylinder, but will not collide with the first simplified figure, where represents the first dimension, which is 1 / 4 the radius of the cylinder. Similarly, Figure 2B There are 11 1 / 4 cylinders remaining in the first simplified figure shown, which can be judged by the same method and will not be described in detail in this embodiment.

[0067] In addition, if the discrete point is located in the bounding box of any 1 / 8 sphere, and the distance between the discrete point and the vertex of the corresponding basic figure of the 1 / 8 sphere is greater than the first size, it is determined that the discrete point will not collide with the first simplified figure.

[0068] For example, Figure 2B Take any 1 / 8 sphere in as an example, and assume that the 1 / 8 sphere is The minimum and maximum values ​​in the axis direction are , then the cubic area formed by these minimum and maximum values ​​is the bounding box of the 1 / 8 sphere. If the coordinates of the discrete points satisfy:

[0069]

[0070] It can be determined that the discrete point is within the bounding box of the 1 / 8 sphere, but will not collide with the first simplified figure. Figure 2B There are still 7 1 / 8 spheres remaining in the first simplified figure shown, which can be judged by the same method and will not be described in detail in this embodiment.

[0071] Finally, the host computer can obtain the arm angle range of the robot arm to avoid obstacles based on the collision detection results of each discrete point.

[0072] for Figure 3B The first simplified graph shown can be used to detect whether an obstacle collides with the shoulder-elbow line and the elbow-wrist line by the following judgment method: For any discrete point on the shoulder-elbow line and the elbow-wrist line , if you hang your feet Located between the endpoints of the basic figure axis, and the foot of the perpendicular between the discrete point and the axis of the basic figure satisfy:

[0073] It is determined that the discrete points will not collide with obstacles, where Indicates the radius of the basic shape, Indicates the second size; If you hang your feet Located on the extension line of the basic figure axis, and the foot of the perpendicular between the discrete point and the axis of the basic figure satisfy:

[0074] It is determined that the discrete points will not collide with obstacles, where Indicates the second size, Represents the coordinates of any endpoint of the basic figure axis; According to the collision detection results of each discrete point, the arm angle range of the robot arm to avoid obstacles is obtained.

[0075] For the third simplified graph, the following judgment method can be used to detect whether the obstacle collides with the shoulder-elbow line and the elbow-wrist line: Assume that the radius of the third simplified figure is , the coordinates of the center of the sphere are , if it satisfies:

[0076] It is determined that the robotic arm will not collide with the spherical obstacle.

[0077] In order to verify the effectiveness of the present invention, the technical effect of the obstacle avoidance path planning method of the seven-degree-of-freedom manipulator in a confined space provided by this embodiment is also verified. Due to its self-motion characteristics, the seven-degree-of-freedom manipulator is particularly suitable for use in work scenarios with limited space, such as assembly production lines and CNC machining. Figure 6 Taking the working scene shown as an example, the robotic arm is arranged on the side of the working scene, which not only saves the space in front of the scene, but also makes the structure of the working area more compact.

[0078] Figure 7 The figure shows the arm angle value range corresponding to each path point under the condition of self-motion obstacle avoidance. It can be seen from the figure that the arm angle value range is It is not difficult to see that the seven-DOF manipulator can achieve the task goal through a variety of arm angle configurations under the same end position, which provides a theoretical basis for its flexibility. When the position of the tool at the end of the manipulator is determined, there are 8 sets of inverse kinematic solutions for the seven-DOF manipulator, which correspond to Figure 7 There are 8 groups of arm angle ranges in the figure. The arm angle value range of each figure is composed of the feasible arm angle range of 54 path points. The arm angle value can be selected arbitrarily within the feasible arm angle range. After selecting a group of arm angles from the starting point to the end point, a group of collision-free paths from the starting point to the end point are obtained through inverse solution. This shows that by analyzing the arm angle value range at different path points, the redundant characteristics of the seven-degree-of-freedom robot can be revealed, and a reference can be provided for subsequent path optimization.

[0079] In summary, this embodiment simplifies the collision model of the robot arm to improve the efficiency of collision detection, thereby speeding up the path planning. On this basis, the present invention further proposes an obstacle avoidance path planning method that utilizes the self-motion characteristics of a seven-degree-of-freedom robot arm, based on the initial path in Cartesian space, to give full play to the redundant characteristics of the robot arm. Further optimization can be carried out later, by selecting the optimal arm angle to achieve the goal of minimizing the movement time during the operation of the robot arm, thereby improving the efficiency of task execution.

[0080] Based on the same inventive concept as the method for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space provided in this embodiment, this embodiment also provides a seven-degree-of-freedom manipulator in a confined space obstacle avoidance path planning device, which includes at least one software function module that can be stored in a memory or fixed in an electronic device in the form of software. The processor in the electronic device is used to execute the executable module stored in the memory 31. For example, the software function module and computer program included in the device. Please refer to Figure 8, functionally speaking, the device may include: An object simplification module 21, used to simplify obstacles in the robot arm working space into simplified graphics that wrap the obstacles; The end position module 22 is used to obtain multiple end positions of the robot arm; An arm angle range module 23 is used to determine, for each end position, a shoulder-elbow connection line and an elbow-wrist connection line corresponding to the inverse kinematics solution corresponding to the end position, wherein the shoulder-elbow connection line represents a connection line between the shoulder and the elbow of the manipulator, and the elbow-wrist connection line represents a connection line between the elbow and the wrist of the manipulator; The arm angle range module 23 is also used to perform collision detection between the simplified graph and the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robot arm to avoid obstacles.

[0081] In this embodiment, the object simplification module 21 is used to implement Figure 1 In step S1, the end posture module 22 is used to implement Figure 1 In step S2, the arm angle range module 23 is used to implement Figure 1 Therefore, for the detailed description of the above modules, please refer to the specific implementation of the corresponding steps.

[0082] In addition, it should be understood that, since the method for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space has the same inventive concept, the device for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space can also implement other steps or sub-steps of the method through the above modules. For example: Optionally, the object simplification module 21 is further specifically configured to: According to the shape of the obstacle, a target shape closest to the shape of the obstacle is determined from multiple candidate shapes; Generate a basic figure that wraps the obstacle according to the target shape, wherein the shape of the basic figure is consistent with the target shape; Inflate a base shape into a simplified shape.

[0083] Optionally, the shape of the basic figure is a cube, a cylinder or a sphere, and the simplified figure is a first simplified figure, a second simplified figure or a third simplified figure; the object simplification module is further specifically used for: If the shape of the basic figure is a cube, the basic figure is expanded by a first size in a direction away from the center position to obtain a first simplified figure, wherein the edges of the basic figure are expanded to 1 / 4 of a cylinder with the first size as a radius, and the vertices of the basic figure are expanded to 1 / 8 of a sphere with the first size as a radius; If the shape of the basic figure is a cylinder, the basic figure is expanded by a second dimension in a direction away from the axis to obtain an expanded cylinder; and half spheres are generated at both ends of the expanded cylinder to obtain a second simplified figure; If the shape of the basic figure is a sphere, the basic figure is expanded by a third dimension in a direction away from the center of the sphere to obtain a third simplified figure.

[0084] Optionally, the arm angle range module 23 is used to perform collision detection on the first simplified graph with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robot arm to avoid obstacles, specifically including: For any discrete point on the shoulder-elbow line and the elbow-wrist line , if the coordinates of the discrete points satisfy: , , , , or

[0085] It is determined that the discrete points will not collide with the first simplified graph, where Indicates that the first simplified graph is Minimum and maximum values ​​in the axis direction; If the coordinates of the discrete points satisfy:

[0086] Then it is determined that the discrete point collides with the first simplified graph, where Indicates that the corresponding basic graphics are Minimum and maximum values ​​in the axis direction; If the discrete point is located in the bounding box of any quarter cylinder, and the distance between the discrete point and the edge of the corresponding basic figure of the quarter cylinder is greater than the first size, it is determined that the discrete point will not collide with the first simplified figure; If the discrete point is located in the bounding box of any 1 / 8 sphere, and the distance between the discrete point and the vertex of the corresponding basic figure of the 1 / 8 sphere is greater than the first size, it is determined that the discrete point and the first simplified figure will not collide; According to the collision detection results of each discrete point, the arm angle range of the robot arm to avoid obstacles is obtained.

[0087] Optionally, the arm angle range module 23 is used to perform collision detection on the second simplified graph with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robot arm to avoid obstacles, specifically including: For any discrete point on the shoulder-elbow line and the elbow-wrist line , if you hang your feet Located between the endpoints of the basic figure axis, and the foot of the perpendicular between the discrete point and the axis of the basic figure satisfy:

[0088] It is determined that the discrete points will not collide with obstacles, where Indicates the radius of the basic shape, Indicates the second size; If you hang your feet Located on the extension line of the basic figure axis, and the foot of the perpendicular between the discrete point and the axis of the basic figure satisfy:

[0089] It is determined that the discrete points will not collide with obstacles, where Indicates the second size, Represents the coordinates of any endpoint of the basic figure axis; According to the collision detection results of each discrete point, the arm angle range of the robot arm to avoid obstacles is obtained.

[0090] Optionally, the end position module 22 is further specifically used for: Generate random nodes; Determine a target node that is closest to the random node from a historical point set, wherein the historical point set includes path exploration points that have been generated for the end of the robotic arm; Determine the node to be evaluated based on the target node, the end point of the robot arm, and the random node; If the line between the target node and the node to be evaluated does not collide with an obstacle, and the node to be evaluated is not within the preset range of the end point, then the node to be evaluated is added to the historical point set, and the process returns to the step of generating random nodes, until a node to be evaluated is obtained within the preset range of the end point and added to the historical point set; If the line between the target node and the node to be evaluated collides with an obstacle, return to the step of generating a random node; A plurality of path points that can connect the starting point of the robot arm to the end point are traversed from the historical point set, and a plurality of end position poses are obtained according to the plurality of path points.

[0091] Optionally, the relationship between the target node, the end point, and the node to be evaluated is:

[0092] In the formula, and represents the preset weight, represents the target node, represents a random node, Indicates the preset growth step size.

[0093] In addition, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0094] It should also be understood that if the above implementation is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, 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, which is stored in a storage medium and includes a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application.

[0095] Therefore, this embodiment further provides a storage medium, which is a computer-readable storage medium. The storage medium stores a computer program, and when the computer program is executed by the processor, the seven-degree-of-freedom manipulator obstacle avoidance path planning method in a confined space provided by this embodiment is implemented. Among them, the storage medium can be a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, etc., which can store program codes.

[0096] This embodiment provides an electronic device for implementing a method for planning a seven-degree-of-freedom robot obstacle avoidance path in a confined space. Fig. 9 As shown, the electronic device may include a processor 32 and a memory 31. In addition, the memory 31 stores a computer program, and the processor implements the seven-degree-of-freedom manipulator obstacle avoidance path planning method in a confined space provided in this embodiment by reading and executing the computer program corresponding to the above implementation in the memory 31.

[0097] Continue to see Fig. 9 The electronic device further includes a communication unit 33. The memory 31, the processor 32 and the communication unit 33 are electrically connected to each other directly or indirectly through a system bus 34 to achieve data transmission or interaction.

[0098] The memory 31 may be an information recording device based on any electronic, magnetic, optical or other physical principle, used to record execution instructions, data, etc. In some embodiments, the memory 31 may be, but is not limited to, a volatile memory, a non-volatile memory, a storage drive, etc.

[0099] In some embodiments, the volatile memory may be a random access memory (RAM); in some embodiments, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), a flash memory, etc.; in some embodiments, the storage drive may be a disk drive, a solid-state drive, any type of storage disk (such as a CD, a DVD, etc.), or a similar storage medium, or a combination thereof, etc.

[0100] The communication unit 33 is used to send and receive data through a network. In some embodiments, the network may include a wired network, a wireless network, a fiber optic network, a telecommunication network, an intranet, the Internet, a local area network (LAN), a wide area network (WAN), a wireless local area network (WLAN), a metropolitan area network (MAN), a wide area network (WAN), a public switched telephone network (PSTN), a Bluetooth network, a ZigBee network, or a near field communication (NFC) network, or any combination thereof. In some embodiments, the network may include one or more network access points. For example, the network may include a wired or wireless network access point, such as a base station and / or a network switching node, and one or more components of the service request processing system may be connected to the network through the access point to exchange data and / or information.

[0101] The processor 32 may be an integrated circuit chip with signal processing capability, and the processor may include one or more processing cores (e.g., a single-core processor or a multi-core processor). By way of example only, the processor may include a central processing unit (CPU), an application specific integrated circuit (ASIC), an application specific instruction set processor (ASIP), a graphics processing unit (GPU), a physical processing unit (PPU), a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a controller, a microcontroller unit, a reduced instruction set computer (RISC), or a microprocessor, or any combination thereof.

[0102] Understandably, Fig. 9 The structure shown is for illustration only. The electronic device may also have Fig. 9 More or fewer components than shown, or with Fig. 9 Different configurations shown. Fig. 9 The components shown may be implemented in hardware, software or a combination thereof.

[0103] It should be understood that the apparatus and method disclosed in the above-mentioned embodiments can also be implemented in other ways. The apparatus embodiments described above are merely schematic. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the apparatus, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, a program segment or a part of a code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of boxes in the block diagram and / or the flowchart can be implemented with a dedicated hardware-based system that performs a specified function or action, or can be implemented with a combination of dedicated hardware and computer instructions.

[0104] The above are only various implementations of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A seven-degree-of-freedom robot obstacle avoidance path planning method in a confined space, characterized in that: The method comprises: Simplifying obstacles in the working space of the robot arm into simplified graphics that enclose the obstacles; Acquire multiple end positions of the robotic arm; For each of the terminal postures, according to the inverse kinematics solution corresponding to the terminal posture, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematics solution, wherein the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the manipulator, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the manipulator; The simplified graph is subjected to collision detection with the elbow-wrist line and the elbow-wrist line to obtain the arm angle range of the robotic arm to avoid the obstacle.

2. The method for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space according to claim 1, characterized in that: Simplifying the obstacles in the working space of the robot arm into a simplified graphic that encloses the obstacles, including: According to the shape of the obstacle, determining a target shape that is closest to the shape of the obstacle from a plurality of candidate shapes; Generating a basic figure that wraps the obstacle according to the target shape, wherein the shape of the basic figure is consistent with the target shape; The base shape is expanded into the simplified shape.

3. The obstacle avoidance path planning method for a seven-degree-of-freedom manipulator in a confined space according to claim 2, characterized in that: The shape of the basic figure is a cube, a cylinder or a sphere, and the simplified figure is a first simplified figure, a second simplified figure or a third simplified figure; Expanding the basic graph into the simplified graph includes: If the shape of the basic figure is the cube, the basic figure is expanded by a first size in a direction away from the center position to obtain the first simplified figure, wherein the edges of the basic figure are expanded to 1 / 4 of a cylinder with the first size as a radius, and the vertices of the basic figure are expanded to 1 / 8 of a sphere with the first size as a radius; If the shape of the basic figure is the cylinder, the basic figure is expanded by a second dimension in a direction away from the axis to obtain an expanded cylinder; and half spheres are generated at both ends of the expanded cylinder to obtain the second simplified figure; If the shape of the basic figure is the sphere, the basic figure is expanded by a third size in a direction away from the center of the sphere to obtain the third simplified figure.

4. The method for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space according to claim 3, characterized in that: The first simplified graph is subjected to collision detection with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robot arm to avoid the obstacle, including: For any discrete point on the shoulder-elbow line and the elbow-wrist line , if the coordinates of the discrete points satisfy: , , , , or It is determined that the discrete point will not collide with the first simplified graph, wherein, The first simplified graph is represented by Minimum and maximum values ​​in the axis direction; If the coordinates of the discrete points satisfy: It is determined that the discrete point collides with the first simplified graph, wherein, Indicates that the corresponding basic graphics are Minimum and maximum values ​​in the axis direction; If the discrete point is located in the bounding box of any of the 1 / 4 cylinders, and the distance between the discrete point and the edge of the corresponding basic figure of the 1 / 4 cylinder is greater than the first size, it is determined that the discrete point will not collide with the first simplified figure; If the discrete point is located in the bounding box of any of the 1 / 8 spheres, and the distance between the discrete point and the vertex of the corresponding basic figure of the 1 / 8 sphere is greater than the first size, it is determined that the discrete point will not collide with the first simplified figure; According to the collision detection result of each of the discrete points, the arm angle range of the robot arm to avoid the obstacle is obtained.

5. The obstacle avoidance path planning method for a seven-degree-of-freedom manipulator in a confined space according to claim 3, characterized in that: The second simplified graph is subjected to collision detection with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robot arm to avoid the obstacle, including: For any discrete point on the shoulder-elbow line and the elbow-wrist line , if you hang your feet Located between the endpoints of the axis of the basic figure, and the foot of the perpendicular between the discrete point and the axis of the basic figure satisfy: It is determined that the discrete point will not collide with the obstacle, wherein, represents the radius of the basic figure, represents the second dimension; If the vertical foot Located on the extension line of the axis of the basic figure, and the foot of the perpendicular between the discrete point and the axis of the basic figure satisfy: It is determined that the discrete point will not collide with the obstacle, wherein, represents the second dimension, Represents the coordinates of any endpoint of the axis of the basic figure; According to the collision detection result of each of the discrete points, the arm angle range of the robot arm to avoid the obstacle is obtained.

6. The obstacle avoidance path planning method for a seven-degree-of-freedom manipulator in a confined space according to claim 1, characterized in that: Acquire multiple end positions of the robotic arm, including: Generate random nodes; Determine a target node that is closest to the random node from a historical point set, wherein the historical point set includes a path exploration point that has been generated for the end of the robotic arm; Determine a node to be evaluated according to the target node, the end point of the end of the robotic arm, and the random node; If the line between the target node and the node to be evaluated does not collide with the obstacle, and the node to be evaluated is not within the preset range of the end point, then the node to be evaluated is added to the historical point set, and the process returns to the step of generating a random node, until a node to be evaluated is within the preset range of the end point and is added to the historical point set; If the line between the target node and the node to be evaluated collides with the obstacle, returning to the step of generating a random node; A plurality of path points that can be connected from the starting point of the robot arm to the end point are traversed from the historical point set, and the plurality of end position poses are obtained according to the plurality of path points.

7. The method for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space according to claim 6, characterized in that: The relationship between the target node, the end point and the node to be evaluated is: In the formula, and represents the preset weight, represents the target node, represents a random node, Indicates the preset growth step size.

8. A seven-degree-of-freedom robot arm obstacle avoidance path planning device in a confined space, characterized in that: The device comprises: An object simplification module, used to simplify obstacles in the working space of the robot arm into simplified graphics that wrap the obstacles; An end position module, used to obtain multiple end positions of the robotic arm; An arm angle range module, for determining, for each of the end postures, a shoulder-elbow connection line and an elbow-wrist connection line corresponding to the inverse kinematics solution corresponding to the end posture, wherein the shoulder-elbow connection line represents a connection line between the shoulder and the elbow of the manipulator, and the elbow-wrist connection line represents a connection line between the elbow and the wrist of the manipulator; The arm angle range module is also used to perform collision detection on the simplified graph with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range of the robotic arm to avoid the obstacle.

9. A storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by the processor, the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space as described in any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: The electronic device includes a processor and a memory, the memory stores a computer program, and when the computer program is executed by the processor, the seven-degree-of-freedom robotic arm obstacle avoidance path planning method in a confined space as described in any one of claims 1-7 is implemented.

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