Method and related device for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space

Abstract

The present application provides a method and related device for obstacle avoidance path planning of a seven-degree-of-freedom manipulator in a confined space, which relates to the field of robot control. Among them, the electronic device simplifies the obstacles in the working space of the manipulator into a simplified graph that wraps the obstacles; and obtains multiple end poses of the manipulator; then, for each end pose, according to the inverse kinematic solution corresponding to the end pose, determines the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution; where 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. Finally, collision detection is performed on the simplified graph, the shoulder-elbow connection line, and the elbow-wrist connection line to obtain the arm angle range for the manipulator to avoid obstacles. In this way, the efficiency of collision detection is improved by simplifying the obstacles, so that the feasible arm angle range of the manipulator can be quickly obtained.

Description

Technical Field

[0001] The present application relates to the field of robot control, and more particularly, 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 a six-degree-of-freedom robotic arm, a seven-degree-of-freedom robotic arm has higher flexibility and is thus widely used in fields such as human-robot collaboration, medical treatment, and aerospace. When performing tasks in Cartesian space, the redundant degrees of freedom of a seven-degree-of-freedom robotic arm endow it with unique self-motion characteristics. However, currently, the path planning of a seven-degree-of-freedom robotic arm still mostly follows the method of a six-degree-of-freedom robotic arm, mainly focusing on joint space planning.

[0003] However, a seven-degree-of-freedom robotic arm has unique local self-motion characteristics. Its elbow can perform circular motion around the straight line formed by the shoulder and the wrist while maintaining the end pose unchanged. However, most current path planning methods are limited to joint space, and the generated paths are usually unique and difficult to further optimize. This results in the ineffective utilization of the self-motion characteristics of a seven-degree-of-freedom robotic arm, thus limiting its potential advantages in tasks such as obstacle avoidance. Therefore, how to efficiently determine the arm angle range of a seven-degree-of-freedom robotic arm to fully utilize its self-motion characteristics has become an urgent problem to be solved. Summary of the Invention

[0004] To overcome at least one deficiency in the prior art, the present application provides a method and related device for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space, specifically including:

[0005] 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 including:

[0006] Simplify the obstacles in the working space of the robotic arm into a simplified graph that encloses the obstacles;

[0007] Obtain multiple end poses of the robotic arm;

[0008] For each of the end poses, according to the inverse kinematic solution corresponding to the end pose, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution, where the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the robotic arm, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the robotic arm;

[0009] Perform collision detection on the simplified graph, the shoulder-elbow connection line, and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid the obstacles.

[0010] In a second aspect, the present application further provides a device for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space, the device including:

[0011] An object simplification module, configured to simplify an obstacle in the working space of the robotic arm into a simplified graph that encloses the obstacle;

[0012] A terminal pose module, configured to obtain multiple terminal poses of the robotic arm;

[0013] An arm angle range module, for each of the terminal poses, according to the inverse kinematic solution corresponding to the terminal pose, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution, wherein the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the robotic arm, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the robotic arm;

[0014] The arm angle range module is further configured to perform a collision detection on the simplified graph, the shoulder-elbow connection line, and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid the obstacle.

[0015] In a third aspect, the present application further provides a storage medium storing a computer program, which when executed by a processor, implements the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space as described above.

[0016] In a fourth aspect, the present application further provides an electronic device, which includes a processor and a memory, the memory stores a computer program, and when the computer program is executed by the processor, it implements the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space according to any one of the above.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The present application provides a method and related device for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space. Among them, the electronic device simplifies an obstacle in the working space of the robotic arm into a simplified graph that encloses the obstacle; and obtains multiple terminal poses of the robotic arm; then, for each terminal pose, according to the inverse kinematic solution corresponding to the terminal pose, determines the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution; wherein, the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the robotic arm, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the robotic arm. Finally, a collision detection is performed on the simplified graph, the shoulder-elbow connection line, and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid the obstacle.

[0019] In this way, the efficiency of collision detection is improved by simplifying the obstacle, so that the feasible arm angle range of the robotic arm can be quickly obtained. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 It is a flowchart of the obstacle avoidance path planning method for a seven-degree-of-freedom robotic arm in a confined space provided by the embodiments of the present application;

[0022] Figure 2A It is a schematic diagram of a cube provided by the embodiments of the present application;

[0023] Figure 2B It is a schematic diagram of the first simplified graph provided by the embodiments of the present application;

[0024] Figure 2C It is a size schematic diagram of the first simplified graph provided by the embodiments of the present application;

[0025] Figure 3A It is a schematic diagram of a cylinder provided by the embodiments of the present application;

[0026] Figure 3B It is a schematic diagram of the second simplified graph provided by the embodiments of the present application;

[0027] Figure 3C It is a size schematic diagram of the second simplified graph provided by the embodiments of the present application;

[0028] Figure 4 It is a principle schematic diagram of the node to be evaluated provided by the embodiments of the present application;

[0029] Figure 5 It is a schematic diagram of the arm angle of the robotic arm provided by the embodiments of the present application;

[0030] Figure 6 It is a schematic diagram of the technical effect verification scenario provided by the embodiments of the present application;

[0031] Figure 7 It is a technical effect verification conclusion graph provided by the embodiments of the present application;

[0032] Figure 8 It is a structural schematic diagram of the obstacle avoidance path planning device for a seven-degree-of-freedom robotic arm in a confined space provided by the embodiments of the present application;

[0033] Figure 9 It is a structural schematic diagram of the electronic device provided by the embodiments of the present application. Detailed implementation manners

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. Components of the embodiments of this application described and illustrated in the accompanying drawings here can be arranged and designed in a variety of different configurations.

[0035] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts fall within the scope of protection of this application.

[0036] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0037] In the description of this application, it should be noted that the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance. In addition, the terms "include", "comprise", or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or device including a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article, or device including the said element.

[0038] Based on the above statement, as introduced in the background art, most current path planning methods are limited to the joint space, and the generated paths are usually unique and difficult to further optimize. This results in the ineffective utilization of the self-motion characteristics of the seven-degree-of-freedom robotic arm, thereby limiting its potential advantages in tasks such as obstacle avoidance. Therefore, how to efficiently determine the range of arm angles of the seven-degree-of-freedom robotic arm to fully utilize its self-motion characteristics has become an urgent problem to be solved.

[0039] Based on the discovery of the above technical problems, the inventors have put forward the following technical solutions through creative labor to solve or improve the above problems. It should be noted that the defects existing in the above solutions in the prior art are the results obtained by the inventors through practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed in the embodiments of the present application below for the above problems should be the contributions made by the inventors to the present application during the invention creation process, rather than being understood as the technical content known to those skilled in the art.

[0040] In view of the discovery of the above problems, an embodiment of the present application (hereinafter simply referred to as this embodiment) provides a method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space. As Figure 1 shown, the method includes:

[0041] S1, simplifying the obstacles in the working space of the robotic arm into a simplified graph that encloses the obstacles.

[0042] S2, obtaining multiple end poses of the robotic arm.

[0043] S3, for each end pose, according to the inverse kinematic solution corresponding to the end pose, determining the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution.

[0044] Among them, the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the robotic arm, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the robotic arm.

[0045] S4, performing collision detection on the simplified graph, the shoulder-elbow connection line, and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid obstacles.

[0046] In this way, the efficiency of collision detection is improved by simplifying the obstacles, so that the feasible arm angle range of the robotic arm can be obtained quickly.

[0047] In this embodiment, the electronic device for implementing the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space may be, but is not limited to, the controller of the robotic arm, and the host computer communicatively connected to the controller of the robotic arm. The host computer may be, but is not limited to, a tablet computer, a laptop computer, a desktop computer, etc.

[0048] To make the solution provided in this embodiment clearer, the following takes the host computer as the electronic device for implementing the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a confined space, and Figure 1 elaborates on each step in the method shown in detail. However, it should be understood that the operations in the flowchart may not be implemented in sequence, and the steps without logical context relationships may be reversed or implemented simultaneously. In addition, those skilled in the art can 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 the present application. AsFigure 1 As shown, the method includes:

[0049] S1. Simplify the obstacles in the working space of the robotic arm into simplified figures that enclose the obstacles.

[0050] In this regard, this embodiment provides multiple candidate shapes for matching with the shape of the obstacle, and selects the target shape with the closest shape therefrom for simplifying the obstacle. Therefore, as an alternative implementation provided by this embodiment, step S1 may include:

[0051] S1-1. Determine the target shape that is closest to the shape of the obstacle from multiple candidate shapes according to the shape of the obstacle.

[0052] S1-2. Generate a basic figure that encloses the obstacle according to the target shape, wherein the shape of the basic figure is the same as the target shape.

[0053] S1-3. Expand the basic figure into a simplified figure.

[0054] Wherein, 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:

[0055] S1-3-1A. If the shape of the basic figure is a cube, expand the basic figure in a direction away from the central position by a first dimension to obtain a first simplified figure.

[0056] Wherein, the edge line of the basic figure is expanded into a 1 / 4 cylinder with the first dimension as the radius, and the vertex of the basic figure is expanded into an 1 / 8 sphere with the first dimension as the radius.

[0057] Exemplarily, referring to Figure 2A the shown basic figure is a cube; after expansion, a first simplified figure as shown in Figure 2B is obtained. It is not difficult to see that each edge line of the basic figure is expanded into a 1 / 4 cylinder with the first dimension as the radius, and the vertex of the basic figure is expanded into an 1 / 8 sphere with the first dimension as the radius. Figure 2C shows Figure 2A the dimensional relationship before and after the expansion of the shown basic figure, wherein, are respectively the minimum and maximum values of the basic figure before expansion in the axis direction, are respectively the minimum and maximum values of the first simplified figure after expansion in the X, Y and Z directions.

[0058] S1-3-1B, if the shape of the basic figure is a cylinder, expand the basic figure in a direction away from the axis by a second dimension to obtain an expanded cylinder; and generate half spheres at both ends of the expanded cylinder to obtain a second simplified figure.

[0059] Exemplarily, referring to Figure 3A the basic figure shown is a cylinder with a radius of ; after expansion, a second simplified figure as shown in Figure 3B is obtained. Assuming that the basic figure is expanded in a direction away from the axis by a second dimension to obtain an expanded cylinder; and generate half spheres at both ends of the expanded cylinder, and the radius of the sphere is . Figure 3C shows Figure 3A the dimensional relationship before and after the expansion of the basic figure shown. Figure 3A The bottom radius of the basic figure shown is , the central axis length is , the intersections of the central axis with the upper and lower surfaces are respectively and , point is one point in the working space, and the foot of the perpendicular to the central axis is .

[0060] S1-3-1C, if the shape of the basic figure is a sphere, expand the basic figure in a direction away from the center of the sphere by a third dimension to obtain a third simplified figure.

[0061] Exemplarily, assume that the basic figure is a sphere with a radius of , and the third dimension is , then the radius of the third simplified figure is .

[0062] In this way, the obstacles in the working space can be simplified into one of the above-mentioned first simplified figure, second simplified figure, and third simplified figure, so as to facilitate subsequent collision detection.

[0063] Based on the above introduction of the simplified figures of the wrapped obstacles, continue to refer to Figure 1 , this method further includes:

[0064] S2, obtain multiple end poses of the robotic arm.

[0065] Among them, each end pose includes a path point and an attitude. The path point represents the three-dimensional coordinates of the end of the robotic arm in the Cartesian space; the attitude represents the rotational state of the end of the robotic arm in the operating space, which is usually described by mathematical tools such as rotation matrices, Euler angles, or quaternions. These parameters define the orientation of the end effector relative to the reference coordinate system, ensuring that the robotic arm can maintain the correct orientation and angle during precise operations.

[0066] For multiple path points at the end of the robotic arm, currently mature algorithms can be used for planning. For example, sampling-based RRT (Rapidly-exploring Random Trees) algorithm, PRM (Probabilistic Roadmap Method) algorithm, genetic algorithm, etc. These algorithms can generate a collision-free path according to the structural characteristics of the robotic arm and the working space limitations, ensuring that the robotic arm moves safely and effectively from the initial pose to the target pose. In this embodiment, step S2 can plan the path of the end of the robotic arm through a derivative algorithm of RRT. As an alternative implementation, step S2 includes:

[0067] S2-1, generating a random node.

[0068] Exemplarily, assuming that the random node is represented as , then the coordinates of this random node can be calculated through the expression:

[0069]

[0070] In the formula, are respectively the minimum and maximum values of the working space of the robotic arm in the axis direction, and is a random point within the range of . This example is only an alternative implementation provided by this embodiment. Of course, other methods can also be selected to obtain random nodes located in the working space.

[0071] Based on the introduction of random nodes in the above embodiment, Figure 1 step S1 in

[0072] also includes:

[0073] S2-2, determining the target node closest to the random node from the historical point set. Figure 4 Among them, the historical point set includes path exploration points that have been generated for the end of the robotic arm. Exemplarily, as , represent the end point as , represent the generated random node as . As can be seen from the figure, for the distance , the path exploration point 11 closest to it is used as the target node, represented as .

[0074] Based on the introduction of the target node in the above embodiment, Figure 1 Step S1 in

[0075] S2-3. Determine the node to be evaluated according to the target node, the end point of the robotic arm, and the random node.

[0076] Exemplarily, continue to refer to Figure 4 , for the target node, random node, and end point in the figure, perform the following operations on the coordinates of the three points to obtain the node to be evaluated, and represent the node to be evaluated as :

[0077]

[0078] In the formula, and represent preset weights, represents the preset growth step.

[0079] S2-4. Determine whether the connection line between the target node and the node to be evaluated collides with an obstacle. If so, return to step S2-1; if not, execute S2-5.

[0080] Among them, when determining whether the connection line between the target node and the node to be evaluated does not collide with an obstacle, a currently mature collision detection algorithm can be adopted. However, it is found in the practical process that the current collision detection algorithm has low efficiency, especially when the shape of the obstacle is irregular, a large amount of computing resources are required. In this embodiment, in order to improve the collision detection efficiency, the obstacle is simplified into a simplified graph enclosing the obstacle, and an efficient collision detection algorithm adapted to the shape of the simplified graph is used to detect whether the connection line between the target node and the node to be evaluated collides with the obstacle. Among them, when determining whether the connection line between the target node and the node to be evaluated collides with the obstacle, the same collision detection algorithm is adopted as when determining whether the simplified graph collides with the shoulder-elbow connection line and the elbow-wrist connection line.

[0081] 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.

[0082] S2-6. Add the node to be evaluated to the historical point set. Then, return to execute step S2-1.

[0083] S2-7. Traverse multiple path points from the historical point set that can connect the starting point of the robotic arm to the ending point, and obtain multiple end poses based on the multiple path points.

[0084] In this way, after multiple rounds of iteration through the above-described embodiments, multiple path points that can connect the starting point of the robotic arm to the ending point can be iterated out; then, based on the poses of the robotic arm end at the starting point and the ending point, the pose of each path point can be obtained through interpolation.

[0085] Exemplarily, since the multiple path points obtained in the Cartesian space through the above-described embodiments only contain position information, it is necessary to assign corresponding pose information to each path point. In this example, based on the pose constraints of the starting point and the ending point of the robotic arm end, the pose of the intermediate point is obtained through linear Euler interpolation. The expression of linear Euler interpolation is:

[0086]

[0087] In the formula, is the Euler angle of the starting point of the robotic arm end, is the Euler angle of the ending point of the robotic arm end, is the value between.

[0088] Based on the introduction of the end pose in the above embodiment, continue to refer to Figure 1 , the method further includes:

[0089] S3. For each end pose, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution according to the inverse kinematic solution corresponding to the end pose.

[0090] Among them, the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the robotic arm, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the robotic arm. For the above shoulder-elbow connection line and elbow-wrist connection line, the following is an example in combination with Figure 5 . The figure shows a seven-degree-of-freedom robotic arm in an S-R-S configuration. The shoulder and wrist of the robotic arm are respectively composed of three intersecting-axis revolute pairs and can be regarded as a spherical hinge. The elbow is composed of a revolute pair. The connecting rods SE and EW can rotate around the straight line SW. The point E v is the starting reference position of the connecting rods SE and EW. When the connecting rods SE and EW rotate to the point E, the angle between E v O and EO is defined as the arm angle ψ . The redundant degrees of freedom of the seven-degree-of-freedom robotic arm are represented by the arm angle. When the pose of the end tool of the robotic arm remains unchanged, controlling the size of the arm angle ψ can control the connecting rods SE and EW of the robotic arm to avoid obstacles in the Cartesian space.

[0091] It should be understood that in the Cartesian space, after obtaining a collision-free path from the starting point to the ending point containing position and pose information, by giving the arm angle value, the inverse solution of the pose of the end of the robotic arm can be used to obtain the joint angles. Among them, the inverse kinematic solution of the robotic arm is a mature technology in the field of robot control, and this embodiment will not elaborate on it anymore.

[0092] Based on the introduction of the shoulder-elbow line and the elbow-wrist line in the above embodiment, continue to refer to Figure 1 , the method further includes:

[0093] S4. Perform collision detection on the simplified graph with the shoulder-elbow line and the elbow-wrist line to obtain the arm angle range for the robotic arm to avoid obstacles.

[0094] Since in this embodiment, the obstacle is simplified into the first simplified graph as shown in Figure 2B and the second simplified graph as shown in Figure 3B , and an efficient collision detection algorithm is provided for these simplified graphs, the following will elaborate on these collision detection algorithms in detail.

[0095] For Figure 2B the first simplified graph shown, the following judgment method can be adopted to detect whether the obstacle collides with the shoulder-elbow line and the elbow-wrist line:

[0096] For any discrete point on the shoulder-elbow line and the elbow-wrist line, if the coordinates of the discrete point satisfy:

[0097] , , , , or

[0098] where represents the minimum and maximum values of the first simplified graph in the axis direction; if the conditions in the above expression are satisfied, it means that the discrete point is outside the bounding box of the first simplified graph. Therefore, it can be determined that the discrete point will not collide with the first simplified graph.

[0099] If the coordinates of the discrete point satisfy:

[0100]

[0101] where represents the minimum and maximum values of the corresponding basic graph in the axis direction; if the conditions in the above expression are satisfied, it means that the discrete point is inside the basic graph. Therefore, it can be determined that the discrete point will collide with the first simplified graph.

[0102] If a discrete point is within the bounding box of any quarter cylinder and the distance between the discrete point and the edge of the basic graph corresponding to the quarter cylinder is greater than the first dimension, it is determined that there is no collision between the discrete point and the first simplified graph.

[0103] Exemplarily, as Figure 2C shown, taking the quarter cylinder shown in the upper left corner of the figure as an example, assuming that the minimum and maximum values of the quarter cylinder shown in the upper left corner in the axis direction are , then the cubic region formed by these minimum and maximum values is the bounding box of the quarter cylinder. If the coordinates of the discrete point satisfy:

[0104]

[0105]

[0106] then it can be determined that the discrete point is within the bounding box of the quarter cylinder but there is no collision with the first simplified graph, where represents the first dimension, that is, the radius of the quarter cylinder. Similarly, Figure 2B the first simplified graph shown in

[0107] also has 11 remaining quarter cylinders, and the same method can be used for judgment, which will not be elaborated in this embodiment.

[0108] In addition, if a discrete point is within the bounding box of any eighth sphere and the distance between the discrete point and the vertex of the basic graph corresponding to the eighth sphere is greater than the first dimension, it is determined that there is no collision between the discrete point and the first simplified graph. Figure 2B Exemplarily, taking any one of the eighth spheres in as an example, and assuming that the minimum and maximum values of the eighth sphere in the axis direction are

[0109]

[0110]

[0111] then it can be determined that the discrete point is within the bounding box of the eighth sphere but there is no collision with the first simplified graph. Similarly, Figure 2B the first simplified graph shown in

[0112] finally, the host computer can obtain the arm angle range for the robotic arm to avoid obstacles based on the collision detection results of each discrete point.

[0113] For Figure 3B the first simplified figure shown, the following judgment method can be adopted to detect whether the obstacle collides with the shoulder-elbow line and the elbow-wrist line:

[0114] For any discrete point on the shoulder-elbow line and the elbow-wrist line , if the foot of the perpendicular is 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 satisfies:

[0115]

[0116] then it is determined that the discrete point will not collide with the obstacle, where represents the radius of the basic figure, represents the second dimension;

[0117] If the foot of the perpendicular is 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 satisfies:

[0118]

[0119] then it is determined that the discrete point will not collide with the obstacle, where represents the second dimension, represents the coordinate of any endpoint of the axis of the basic figure;

[0120] According to the collision detection results of each discrete point, the arm angle range for the robotic arm to avoid obstacles is obtained.

[0121] For the third simplified figure, the following judgment method can be adopted to detect whether the obstacle collides with the shoulder-elbow line and the elbow-wrist line:

[0122] Assume that the radius of the third simplified figure is , and the center coordinate of the sphere is . If the following conditions are satisfied:

[0123]

[0124] then it is determined that the robotic arm will not collide with the spherical obstacle.

[0125] To verify the effectiveness of the present invention, a technical effect verification was also carried out on the obstacle avoidance path planning method for the seven-degree-of-freedom robotic arm in a restricted space provided in this embodiment. Due to its self-motion characteristics, the seven-degree-of-freedom robotic arm is particularly suitable for working scenarios with restricted space, such as assembly production lines and numerical control machining. Taking Figure 6Taking 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.

[0126] 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.

[0127] 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.

[0128] 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:

[0129] An object simplification module 21, used to simplify obstacles in the robot arm working space into simplified graphics that wrap the obstacles;

[0130] The end position module 22 is used to obtain multiple end positions of the robot arm;

[0131] The arm angle range module 23 is configured to, for each end pose, determine the shoulder-elbow connection line and the elbow-wrist connection line corresponding to the inverse kinematic solution according to the inverse kinematic solution corresponding to the end pose, where the shoulder-elbow connection line represents the connection line between the shoulder and the elbow of the robotic arm, and the elbow-wrist connection line represents the connection line between the elbow and the wrist of the robotic arm;

[0132] The arm angle range module 23 is further configured to perform collision detection on the simplified graph with the shoulder-elbow connection line and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid obstacles.

[0133] In this embodiment, the object simplification module 21 is configured to implement Figure 1 step S1 in Figure 1 the arm angle range module 23 is configured to implement Figure 1 steps S3 and S4 in. Therefore, for the detailed descriptions of the above modules, reference may be made to the specific embodiments of the corresponding steps.

[0134] In addition, it should be further understood that since the obstacle avoidance path planning device for a seven-degree-of-freedom robotic arm in a restricted space has the same inventive concept as the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space, the obstacle avoidance path planning device for a seven-degree-of-freedom robotic arm in a restricted space can also implement other steps or sub-steps of the method through the above modules. For example:

[0135] Optionally, the object simplification module 21 is further specifically configured to:

[0136] Determine the target shape that is closest to the shape of the obstacle from multiple candidate shapes according to the shape of the obstacle;

[0137] Generate a basic graph that wraps the obstacle according to the target shape, where the shape of the basic graph is the same as the target shape;

[0138] Inflate the basic graph into a simplified graph.

[0139] Optionally, the shape of the basic graph is a cube, a cylinder, or a sphere, and the simplified graph is a first simplified graph, a second simplified graph, or a third simplified graph; the object simplification module is further specifically configured to:

[0140] If the shape of the basic graph is a cube, inflate the basic graph in a direction away from the center position by a first dimension to obtain a first simplified graph, where the edges of the basic graph are inflated into 1 / 4 cylinders with the first dimension as the radius, and the vertices of the basic graph are inflated into 1 / 8 spheres with the first dimension as the radius;

[0141] If the shape of the basic graph is a cylinder, inflate the basic graph in a direction away from the axis by a second dimension to obtain an inflated cylinder; and generate half spheres at both ends of the inflated cylinder to obtain a second simplified graph;

[0142] If the shape of the basic figure is a sphere, the basic figure is expanded in a direction away from the center of the sphere by a third dimension to obtain a third simplified figure.

[0143] Optionally, the arm angle range module 23 is used to perform collision detection on the first simplified figure with the shoulder-elbow connection line and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid obstacles, specifically including:

[0144] For any discrete point on the shoulder-elbow connection line and the elbow-wrist connection line , if the coordinates of the discrete point satisfy:

[0145] , , , , or

[0146] then it is determined that the discrete point will not collide with the first simplified figure, where, represents the minimum and maximum values of the first simplified figure in the axis direction;

[0147] If the coordinates of the discrete point satisfy:

[0148]

[0149] then it is determined that the discrete point collides with the first simplified figure, where, represents the minimum and maximum values of the corresponding basic figure in the axis direction;

[0150] If the discrete point is within the bounding box of any 1 / 4 cylinder, and the distance between the discrete point and the edge of the 1 / 4 cylinder corresponding to the basic figure is greater than the first dimension, then it is determined that the discrete point will not collide with the first simplified figure;

[0151] If the discrete point is within the bounding box of any 1 / 8 sphere, and the distance between the discrete point and the vertex of the 1 / 8 sphere corresponding to the basic figure is greater than the first dimension, then it is determined that the discrete point will not collide with the first simplified figure;

[0152] According to the collision detection results of each discrete point, the arm angle range for the robotic arm to avoid obstacles is obtained.

[0153] Optionally, the arm angle range module 23 is used to perform collision detection on the second simplified figure with the shoulder-elbow connection line and the elbow-wrist connection line to obtain the arm angle range for the robotic arm to avoid obstacles, specifically including:

[0154] For any discrete point on the shoulder-elbow connection line and the elbow-wrist connection line , if the foot of the perpendicular 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:

[0155]

[0156] Then it is determined that there will be no collision between the discrete point and the obstacle, where Represents the radius of the basic figure Represents the second dimension;

[0157] If the foot of the perpendicular Is 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:

[0158]

[0159] Then it is determined that there will be no collision between the discrete point and the obstacle, where Represents the second dimension Represents the coordinates of any one endpoint of the axis of the basic figure;

[0160] According to the collision detection results of each discrete point, the arm angle range for the robotic arm to avoid obstacles is obtained.

[0161] Optionally, the end pose module 22 is further specifically configured to:

[0162] Generate random nodes;

[0163] Determine the target node closest to the random node from the historical point set, where the historical point set includes the path exploration points already generated for the end of the robotic arm;

[0164] Determine the node to be evaluated according to the target node, the end point of the robotic arm end, and the random node;

[0165] If the connection 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 add the node to be evaluated to the historical point set and return to the step of generating random nodes until a node to be evaluated within the preset range of the end point is obtained and added to the historical point set;

[0166] If the connection line between the target node and the node to be evaluated collides with the obstacle, then return to the step of generating random nodes;

[0167] Traverse multiple path points that can connect from the starting point of the robotic arm to the end point from the historical point set, and obtain multiple end poses according to the multiple path points.

[0168] Optionally, the relationship between the target node, the end point, and the node to be evaluated is:

[0169]

[0170] In the formula, and represent preset weights, represents the target node, represents the random node, represents the preset growth step.

[0171] In addition, in each embodiment of the present application, the functional modules can be integrated together to form an independent part, or each module can exist alone, or two or more modules can be integrated to form an independent part.

[0172] It should also be understood that if the above implementation manner is implemented in the form of a software functional 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, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application.

[0173] Therefore, this embodiment also provides a storage medium, which is a computer-readable storage medium. This storage medium stores a computer program, and when the computer program is executed by a processor, it implements the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space provided in this embodiment. Among them, the storage medium can be various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk, or an optical disc that can store program codes.

[0174] An electronic device for implementing the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space provided in this embodiment. As Figure 9 shown, the electronic device may include a processor 32 and a memory 31. And, the memory 31 stores a computer program, and the processor reads and executes the computer program corresponding to the above implementation manner in the memory 31 to implement the method for obstacle avoidance path planning of a seven-degree-of-freedom robotic arm in a restricted space provided in this embodiment.

[0175] Continue to refer to Figure 9, the electronic device further includes a communication unit 33. Each of the memory 31, the processor 32, and the communication unit 33 is directly or indirectly electrically connected to each other through a system bus 34 to achieve data transmission or interaction.

[0176] Among them, the memory 31 can be an information recording device based on any electronic, magnetic, optical, or other physical principles for recording execution instructions, data, etc. In some embodiments, the memory 31 can be, but is not limited to, a volatile memory, a non-volatile memory, a storage drive, etc.

[0177] In some embodiments, the volatile memory can be a random access memory (RAM); in some embodiments, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, etc.; in some embodiments, the storage drive can be a disk drive, a solid-state drive, any type of storage disk (such as an optical disk, a DVD, etc.), or a similar storage medium, or a combination thereof, etc.

[0178] The communication unit 33 is used to transmit and receive data via a network. In some embodiments, the network may include a wired network, a wireless network, an optical fiber 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, etc., 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 via the access point to exchange data and / or information.

[0179] The processor 32 may be an integrated circuit chip with signal processing capabilities, 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 above-mentioned 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 physics 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 computing (RISC), or a microprocessor, etc., or any combination thereof.

[0180] It can be understood that Figure 9The structure shown is only illustrative. The electronic device may also have more or fewer components than Figure 9 shown, or have a different configuration from Figure 9 shown. Figure 9 Each of the components shown may be implemented by hardware, software, or a combination thereof.

[0181] It should be understood that the devices and methods disclosed in the above embodiments may also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the drawings show the possible architectures, functions, and operations of devices, methods, and computer program products according to multiple embodiments of the present application. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of 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 blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system for performing the specified functions or actions, or may be implemented by a combination of dedicated hardware and computer instructions.

[0182] As described above, these are only various embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to 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 the obstacles in the working space of the robot arm into a simplified graphic that encloses the obstacles, specifically 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; 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, 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 specifically 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 dimension in a direction away from the center of the sphere to obtain the third simplified figure; 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: 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.

3. The obstacle avoidance path planning method for a seven-degree-of-freedom manipulator in a confined space according to claim 1, 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.

4. 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: 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.

5. The obstacle avoidance path planning method for a seven-degree-of-freedom manipulator in a confined space according to claim 4, 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.

6. A seven-degree-of-freedom robot arm obstacle avoidance path planning device in a confined space, characterized in that: The device comprises: The object simplification module is used to simplify the obstacles in the working space of the robot arm into a simplified graphic that wraps the obstacles, specifically 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; 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, 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 specifically 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 dimension in a direction away from the center of the sphere to obtain the third simplified figure; 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.

7. 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 5 is implemented.

8. 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 1-5 is implemented.

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