Arm shape planning method and arm shape planning device for segmented linkage mechanical arm

Abstract

The present application proposes an arm shape planning method and an arm shape planning device, an electronic device, and a non-transient computer-readable storage medium for a segmented linkage robotic arm. The segmented linkage robotic arm includes a plurality of robotic arm segments. The arm shape planning method includes: presetting a robotic arm segment weight for each robotic arm segment of the segmented linkage robotic arm; determining the rotation angle of each of the plurality of robotic arm segments according to the end posture of the segmented linkage robotic arm and the preset bending weight, so as to minimize the arm shape bending degree of the segmented linkage robotic arm. According to an embodiment of the present application, by uniformly describing the arm shape bending degree, an optimal joint angle that meets the requirements is obtained according to the arm shape planning problem of the segmented linkage robotic arm, thereby improving the arm shape planning efficiency of the segmented linkage robotic arm in a non-structural task environment and reducing the engineering application difficulty of the segmented linkage robotic arm.

Description

Technical Field

[0001] The present application relates to the field of segmented linkage robotic arms, and in particular, to an arm shape planning method and arm shape planning device, electronic equipment, and non-transitory computer-readable storage medium of a segmented linkage robotic arm. Background Art

[0002] Rope-driven (referred to as rope-driven) manipulators with good bending characteristics play an increasingly important role in the daily monitoring and maintenance of equipment such as spacecraft, aircraft and nuclear facilities. Thanks to the design concept of separating the drive control device from the actuator, the rope-driven manipulator can achieve remote power transmission, and its drive control unit can effectively isolate the influence of the external environment such as high and low temperatures, nuclear pollution, etc.

[0003] In order to further improve the end load capacity of the rope-driven manipulator, the rope-driven segmented linkage manipulator came into being. Through the combination of intra-segment linkage and inter-segment freedom, the rope-driven manipulator improves the stiffness of the entire arm while maintaining flexibility, thereby improving its end load capacity; in addition, the linkage design also reduces the complexity of the drive device, enhancing its adaptability and operating efficiency in non-structural environments.

[0004] In order to give full play to the design potential of segmented linkage manipulators, it is necessary to describe the whole arm shape to reveal its own geometric characteristics and its interaction with the working environment. At the same time, in order to complete specific tasks, such as narrow space exploration and complex space target grasping, efficient arm shape planning methods are also needed to provide necessary references for the design of joint drive control laws. However, the current arm shape planning methods have the following main drawbacks:

[0005] (1) There is currently no method described to reveal the overall arm geometry of a robotic arm.

[0006] The shape of the entire robotic arm cannot be described by using joint angles or the bending angles of each segment. They only describe the partial shape of the robotic arm and it is difficult to intuitively describe the unfolded shape of the entire arm in the workspace.

[0007] (2) Direct planning of joint angles is inefficient, which greatly limits the engineering implementation of the planning algorithm.

[0008] The joint angles are directly mapped to the positions of the joints and the end effector in the workspace of the robot, without considering the linkage characteristics of the linked robot. This implementation results in a lot of useless overhead of computing resources, and the engineering implementation of the whole-arm arm shape planning algorithm in a complex obstacle environment is difficult.

[0009] (3) The arm shape planning method of segmented linkage robotic arms varies from arm to arm, and there is no unified description method. The whole arm shape planning problem urgently needs a universal description framework to increase the process and feasibility of arm shape planning.

[0010] In view of the above problems, the present invention proposes a series of segment bending indices, inter-segment bending indices and whole-arm bending indices to describe the bending characteristics of the segmented linkage robotic arm based on the relevant theories of curve theory, revealing the geometric essence of the whole arm shape of the robotic arm; and proposes an arm shape planning method based on curve bending optimization, which unifies the mathematical description of the arm shape planning problem from the perspective of optimization, and provides a theoretical basis and engineering implementation solution for efficient arm shape planning of the segmented linkage robotic arm in a non-structural task environment. Summary of the invention

[0011] The present invention aims to provide an arm shape planning method and arm shape planning device, electronic equipment and non-transitory computer-readable storage medium for a segmented linkage robotic arm, so as to solve at least one of the problems mentioned above.

[0012] According to one aspect of the present application, a method for arm shape planning of a segmented linkage robotic arm is proposed, wherein the segmented linkage robotic arm includes multiple robotic arm segments, and the arm shape planning method includes: presetting a robotic arm segment weight for each robotic arm segment of the segmented linkage robotic arm; determining a rotation angle of each of the multiple robotic arm segments according to the end posture of the segmented linkage robotic arm and the preset bending weight, so as to minimize the degree of arm shape bending of the segmented linkage robotic arm.

[0013] According to some embodiments, the arm bending degree of the segmented linkage mechanical arm is described by an arm bending index, and the arm bending index is determined by an arm curvature index and an arm torsion index.

[0014] According to some embodiments, the arm bending index is represented by the following formula:

[0015]

[0016] in, represents the arm curvature index of the segmented linkage robotic arm, It represents the arm torsion index of the segmented linkage robot arm.

[0017] According to some embodiments, the arm segment weight includes an arm bending weight value, an arm curvature weight, and an arm torsion weight, and the arm curvature index is determined by the following formula:

[0018] ;

[0019] The arm torsion index is determined by the following formula:

[0020] ;

[0021] in, , , , , , , For the i The curvature index of each robot segment, For the i The torsion index of each robot segment, m is the total number of robot segments in the segmented linkage robot, is the preset arm bending weight value, For the i The arm curvature weight of each robot segment, No. i The arm torsion weight of each robot segment.

[0022] According to some embodiments, the coordinate system in which each of the robotic arm segments is located includes a first coordinate axis, a second coordinate axis and a third coordinate axis, and the first coordinate axis, the second coordinate axis and the third coordinate axis are perpendicular to each other, the first coordinate axis is parallel to the elongation direction of the robotic arm segment, and the rotation angle of each of the robotic arm segments includes a first rotation angle and a second rotation angle, wherein determining the rotation angle of each of the multiple robotic arm segments includes: rotating each of the robotic arm segments from an initial coordinate system around a direction indicated by the third coordinate axis to obtain a first temporary coordinate system and the first rotation angle; rotating each of the robotic arm segments from the first temporary coordinate system around a direction indicated by the second coordinate axis to obtain the second rotation angle.

[0023] According to some embodiments, each robot arm segment includes a plurality of sections, and the curvature index of each of the robot arm segments is as follows:

[0024] or ,

[0025] in, is the curvature index of the i-th robot segment, r i For the i The radius of the plane circle where the robot arm segments are located, , l i For the i The length of each robot segment, , For the i The first rotation angle of each robot segment, For the i The second rotation angle of each robot segment.

[0026] According to some embodiments, the torsion index of each of the robot arm segments is as follows:

[0027] ,

[0028] in, is the torsion index of each of the robot arm segments, For the i The normal vector of the plane on which the robot segment lies, For the i+1 Normal vector of the plane on which the robot segment lies.

[0029] According to some embodiments, i The normal vector of the plane where each robot segment is located is shown as follows:

[0030] or

[0031]

[0032] in, For the i The normal vector of the plane on which the robot segment lies, For the i The first rotation angle of each robot segment, For the i The second rotation angle of the robot arm segment.

[0033] According to some embodiments, when the arm bending degree of the segmented linkage robotic arm is the smallest, the satisfied constraints include: the end posture and the rotation angle of each robotic arm segment satisfy the robotic arm kinematic constraints; the segmented linkage robotic arm operates in a preset workspace; the first rotation angle is within a preset threshold range; and / or the second rotation angle is within a preset threshold range.

[0034] According to one aspect of the present application, an arm shape planning device for a segmented linkage robot arm is proposed, comprising: a segment weight preset unit, used to preset a robot arm segment weight for each robot arm segment of the segmented linkage robot arm; an arm shape planning calculation unit, used to determine the rotation angle of each robot arm segment among the multiple robot arm segments according to the end posture of the segmented linkage robot arm and the preset bending weight, so as to minimize the arm shape bending degree of the segmented linkage robot arm.

[0035] According to one aspect of the present application, an electronic device is proposed, comprising: a processing unit; and a storage unit storing a computer program, wherein when the computer program is executed by the processing unit, the processing unit executes the arm shape planning method as described in any of the preceding items.

[0036] According to one aspect of the present application, a non-transitory computer-readable storage medium is provided, on which computer-readable instructions are stored. When the instructions are executed by a processor, the processor executes the arm shape planning method as described in any of the preceding items.

[0037] According to the embodiments of the present application, by uniformly describing the degree of arm bending, the optimal joint angle that meets the needs is obtained according to the arm planning problem of the segmented linkage robotic arm, thereby improving the arm planning efficiency of the segmented linkage robotic arm in a non-structural task environment and reducing the difficulty of engineering application of the segmented linkage robotic arm.

[0038] It is to be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. By describing the exemplary embodiments in detail with reference to the drawings, the above and other objectives, features and advantages of the present invention will become more apparent.

[0040] Figure 1 A flow chart of an arm shape planning method for a segmented linkage robotic arm according to an example embodiment of the present application is shown.

[0041] Figure 2 A schematic diagram of a segmented linkage robotic arm including a plurality of robotic arm segments according to an exemplary embodiment of the present application is shown.

[0042] Figure 3 A flow chart of a process for calculating the degree of arm bending according to an exemplary embodiment of the present application is shown.

[0043] Figure 4 A schematic diagram of a reference coordinate system of a segmented linkage robot arm according to an exemplary embodiment of the present application is shown.

[0044] Figure 5 A schematic diagram of a segment coordinate system of each robot arm segment in a segmented linkage robot arm according to an exemplary embodiment of the present application is shown.

[0045] Figure 6 A schematic diagram of a section coordinate system of each section in a robotic arm segment according to an exemplary embodiment of the present application is shown.

[0046] Figure 7 A schematic diagram of the rotation angle of a robot arm segment according to an exemplary embodiment of the present application is shown.

[0047] Figure 8 A schematic diagram of a plane where a robot arm segment is located and a corresponding normal vector according to an exemplary embodiment of the present application is shown.

[0048] Figure 9a A schematic diagram of a robot arm type planning result according to an example embodiment of the present application is shown.

[0049] Figure 9b A schematic diagram of another robot arm type planning result according to an exemplary embodiment of the present application is shown.

[0050] Fig.9c A schematic diagram of another robot arm type planning result according to an exemplary embodiment of the present application is shown.

[0051] Figure 9d A schematic diagram of another robot arm type planning result according to an exemplary embodiment of the present application is shown.

[0052] Fig.10a A schematic diagram of an arm shape planning method according to an example embodiment of the present application is shown for optimizing the effect of a T-shaped working area.

[0053] Fig.10b A schematic diagram of the process of optimizing the effect of applying another arm-type planning method to a T-shaped working area according to an exemplary embodiment of the present application is shown.

[0054] Fig.10c A schematic diagram of the process of optimizing the effect of applying another arm-type planning method to a T-shaped working area according to an exemplary embodiment of the present application is shown.

[0055] Fig.10d A schematic diagram of the process of optimizing the effect of applying another arm-type planning method to a T-shaped working area according to an exemplary embodiment of the present application is shown.

[0056] Fig.11 A block diagram of an arm type planning device for a segmented linkage robotic arm according to an exemplary embodiment of the present application is shown.

[0057] Fig.12 An electronic device according to an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0058] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same figures in the drawings represent the same or similar parts, and thus their repeated description will be omitted.

[0059] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other modes, components, materials, devices or operations may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0060] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps can be decomposed, and some operations / steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0061] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0062] The specific embodiments according to the present invention are described in detail below with reference to the accompanying drawings.

[0063] Figure 1 A flow chart of an arm type planning method for a segmented linkage mechanical arm according to an exemplary embodiment of the present application is shown. Figure 1 The arm shape planning method shown includes steps S101, S103 and S105. Figure 1 Taking as an example, a method for planning the arm type of a segmented linkage robot arm according to an exemplary embodiment of the present application is described in detail.

[0064] According to an embodiment of the present application, the segmented linkage robot arm includes a plurality of robot arm segments, and each robot arm segment includes a plurality of sections. Figure 2As shown, a segmented linkage robot includes multiple robot arm segments. A group of connecting rods and joints that move at equal angles or with equal curvatures in the segmented linkage robot is called a segment, and each connecting rod in the segment is called a section. Among them, one end of the robot arm on which the actuator is installed is called the end, and the other end is called the root. The ends of the segment and the section close to the root of the robot arm are called the root of the segment and the root of the section, respectively, and the sides of the segment and the section close to the end of the robot arm are called the end of the segment and the end of the section, respectively. Definition: In this embodiment, the numbering of the segments and sections is gradually increased from the root to the end, and the direction extending from the root to the end is called the elongation direction of the robot arm, segment, and section.

[0065] like Figure 1 As shown, in step S101, a robot segment weight is preset for each robot segment of the segmented linkage robot arm.

[0066] In the embodiment of the present application, the weight of the robot arm segment measures the degree of bending within each robot arm segment and the degree of twisting between segments. In a specific embodiment, the weight value of the robot arm segment can be set as needed, and is not specifically limited here. For example, when a certain segment of the robot arm needs to bend more, a smaller weight value can be set, and when a certain segment of the robot arm needs to bend less, a larger weight value can be set for the segment.

[0067] In step S103, according to the end posture of the segmented linkage robot arm and the preset bending weight, the rotation angle of each robot arm segment in the plurality of robot arm segments is determined to minimize the arm bending degree of the segmented linkage robot arm.

[0068] From the perspective of arm shape planning and kinematic planning, when the entire arm shape is bent as little as possible while completing the task, the control of the arm is easier and the control energy consumption is lower. Therefore, the index function of arm shape planning can be selected as arm shape bending. According to the embodiment of the present application, formula (1) is used to describe the minimum arm shape bending degree of the segmented linkage robot.

[0069] (1)

[0070] According to an embodiment of the present application, the optimization variable The kinematic constraints of the robot arm should be met, that is, the end position With joint angle The relationship is shown in formula (2).

[0071] (2)

[0072] in , the functional relationship It can be described by a homogeneous matrix described by the DH (Denavit–Hartenberg) parameters of the manipulator.

[0073] It should be noted that in the field of mechanics, the joint angle refers to the rotation angle of the previous section of each linkage robot arm relative to the next section. Since in the embodiment, each section of each linkage robot arm moves at the same angle or with the same curvature, in this application, the joint angle is used to describe the rotation angle of the previous linkage robot arm segment relative to the next linkage robot arm segment.

[0074] In a specific embodiment, for a specific task, the segmented linkage robotic arm must also meet the constraints of its working environment, such as: the robotic arm must work in a preset working space, and a certain section must be in a fixed plane; at the same time, the robotic arm's own rotation angle must be within a preset threshold range.

[0075] In practice, according to formula (2), multiple end-effector postures can be obtained: Corresponding joint angle According to this embodiment, according to formula (1) and the constraints when satisfying a specific task, multiple positions and postures of the end actuator can be obtained. Corresponding joint angle Determine the optimal joint angle .

[0076] According to an embodiment of the present application, the arm bending degree of the segmented linkage robotic arm is described by an arm bending index, and the arm bending index is determined by an arm curvature index and an arm torsion index.

[0077] It should be noted that the arm bending degree can be characterized by any combination of arm curvature index and arm torsion index, such as power, polynomial or exponential combination, etc. This application does not specifically limit this.

[0078] In some specific embodiments, the arm bending degree of the segmented linkage robot arm is the sum of the arm curvature index and the arm torsion index, and the robot arm segment weight includes the arm bending weight value, the arm curvature weight and the arm torsion weight, as shown in formula (3).

[0079] (3)

[0080] in, is the arm curvature index of the segmented linkage robot arm, is the arm torsion index of the segmented linkage robot arm, , , , , , , , , For the i The curvature index of each robot segment, For thei The torsion index of each robot segment, m is the total number of robot segments in the segmented linkage robot, is the preset arm bending weight value, For the i The arm curvature weight of each robot segment, No. i The arm torsion weight of each robot segment.

[0081] According to an embodiment of the present application, and The degree of bending within the entire robot arm segment and the degree of twisting between segments were measured respectively. and The differences in curvature and torsion between segments of the entire robotic arm were measured respectively. and The smaller it is, the closer the entire robot arm shape is to a straight line. and The smaller it is, the closer the whole robot arm shape is to the segmented cylindrical helix. When the value is small, the linkage section will have a greater degree of bending, and the linkage section will be more "soft". On the contrary, when the design weight of a section is When the value is larger, the linkage section bends less and appears "hard". Therefore, by using the preset arm bending weight value, arm curvature weight and / or arm torsion weight, according to the embodiment of the present application, a mechanical arm shape that meets the task objectives can be obtained.

[0082] according to Figure 1 The embodiment shown, by uniformly describing the degree of arm bending, obtains the optimal joint angle that meets the needs according to the arm planning problem of the segmented linkage robotic arm, thereby improving the arm planning efficiency of the segmented linkage robotic arm in non-structural task environments and reducing the difficulty of engineering applications of the segmented linkage robotic arm.

[0083] In order to quantify the degree of arm bending in the embodiment of the present application, the arm type and index of the mechanical arm are defined in the present embodiment. Figure 3 Taking the flowchart shown as an example, the calculation process of the arm bending degree according to the exemplary embodiment of the present application is described in detail. For the convenience of description, the segmented linkage mechanical arm is replaced by a mechanical arm.

[0084] According to an embodiment of the present application, the coordinate system in which each robotic arm segment is located includes a first coordinate axis, a second coordinate axis, and a third coordinate axis, and the first coordinate axis, the second coordinate axis, and the third coordinate axis are perpendicular to each other, the first coordinate axis is parallel to the elongation direction of the robotic arm segment, and the rotation angle of each robotic arm segment includes a first rotation angle and a second rotation angle. In a specific embodiment, when determining the rotation angle of each robotic arm segment in a plurality of robotic arm segments, first, each robotic arm segment is rotated from an initial coordinate system in a direction indicated by the third coordinate axis to obtain a first temporary coordinate system and a first rotation angle; then, each robotic arm segment is rotated from the first temporary coordinate system in a direction indicated by the second coordinate axis to obtain a second rotation angle.

[0085] In order to have a more intuitive understanding of the rotation angle, before describing in detail the calculation process of the arm bending degree, firstly perform step S301 to define the coordinate system of the segmented linkage robot arm.

[0086] In step S301, the coordinate system of the segmented linkage robot is defined.

[0087] In this embodiment, the coordinate system of the segmented linkage robot is first defined, then the coordinate system of each robot segment in the segmented linkage robot is defined, and finally, the coordinate system of each section in each robot segment is defined.

[0088] like Figure 4 FIG. 1 is a schematic diagram of a reference coordinate system of a segmented linkage mechanical arm according to an exemplary embodiment of the present application. Figure 4 As shown in the figure, the cylinder on the left represents the robot drive control box. The different segments of the robot are distinguished by the gaps in the middle of the line segments. The state shown in the figure is the zero position state of each universal joint, each joint angle is zero, and the robot is extended along a straight line. The origin O is taken as the intersection of the two rotation axes of the universal joint connecting the root of the robot and the robot drive control box. The direction is along the extension direction of the arm when each joint of the robot is in zero position, that is, the extension direction from the root to the end, pointing to the end of the robot arm. The OY0 axis and the OZ0 axis are both perpendicular to OX0, forming a right-handed rectangular coordinate system. For convenience, the OY0 axis and the OZ0 axis can be taken as two orthogonal rotation axes of the universal joint, representing the pitch [P] and yaw [Y] directions respectively.

[0089] In this embodiment, it is assumed that the segmented linkage robot arm includes m robot arm segments, and the jth segment includes n j Section, that is, the total number of sections of the robot arm is m, and the total number of sections of the jth section is n j , so the total number of robot arms is . Assume that the lengths of the sections in the same segment are equal, and the length of each section in the i-th segment is l i In this embodiment, it is not limited whether the lengths of different segments are the same.

[0090] Figure 5 A schematic diagram of a segment coordinate system of each robot arm segment in a segmented linkage robot arm according to an exemplary embodiment of the present application is shown. Figure 5 As shown in the figure, different colors distinguish different segments, line segments represent joints, and points between line segments represent universal joints. Each universal joint has two degrees of freedom: pitch and yaw. i Robot segments, origin O i Take the first i The last section of the robot arm segment i+1 The segment connects the intersection of the two rotation axes of the universal joint. i=m When, origin o m Take the first m The connection point between the last section of the paragraph and the end actuator; i Robot arm segment o i x i Axis i The last section of the robot arm is pointing to the i The extension direction of the robot arm segment, o i y i Axis and o i z i The axis is taken as i The directions of the two rotation axes when the universal joint angle of the last segment of the robot arm connecting the last segment and the previous segment is 0; i=0 , the coordinate system o0x0y0z0 coincides with the reference coordinate system OX0Y0Z0.

[0091] Figure 6 A schematic diagram of a section coordinate system of each section in a robot arm segment according to an exemplary embodiment of the present application is shown. Figure 6 As shown, i Robot arm segment j Nodal Coordinate System o i,j x i,j y i,y z i, origin o i,j Defined at the end of each section, o i,j x i,j Axis i Section jThe node points to the direction of elongation of the node. o i,j y i,j Axis and o i,j z i,j The axis direction is defined as the direction of the rotation axis when the universal joint angle at the root of the node is 0. It can be seen that the node coordinate system With segment coordinate system Coincident. Section coordinate system o i,j x i,j y i,y z i,j origin o i,j The universal joint is called the first ( i, j ) joints, the universal joint where the origin O of the reference coordinate system OX0Y0Z0 is located is called the 0th joint.

[0092] According to the above coordinate system definition, i The curvature of a segment can be determined by the segment coordinate system o i x i y i z i Relative to segment coordinate system o i-1 x i-1 y i-1 z i-1 The pose description of the end effector of the robot arm is given by the segment coordinate system o m x m y m z m or node coordinate system Relative to the reference coordinate system Description of the pose.

[0093] In step S303, the arm curvature index of each segment is calculated according to the rotation angle of each robot arm segment.

[0094] According to the mechanical design of the segmented linkage robot arm, the universal joints in each segment of the robot arm are allocated with PY-YP-PY-... (i.e., pitch-yaw-yaw-pitch-pitch-yaw-...) or YP-PY-YP-... (i.e., yaw-pitch-pitch-yaw-yaw-pitch-...) degrees of freedom in turn to ensure that the links in the segment move at equal angles and are in the same plane. To this end, first determine the plane normal vector of each segment link and the angle of each joint in the segment relative to the normal vector. In this embodiment, for the first segment of the robot arm, i The direction of the first link can be determined by the two rotation angles of the universal joint. The following takes the YP rotation as an example to give a method for determining the rotation vector and rotation angle of each segment.

[0095] Figure 7 A schematic diagram of the rotation angle of a robot arm segment according to an exemplary embodiment of the present application is shown. o i-1 x i-1 y i-1 z i-1 In i The direction of the first section of a segment is determined by the segment coordinate system o i-1 x i-1 The axis first o i-1 z i-1 Axis rotation first rotation angle , then around Axis rotation second rotation angle Get, such as Figure 7 As shown. Among them, the segment coordinate system o i-1 x i-1 y i-1 z i-1 Around o i-1 z i-1 Axis rotation The temporary coordinate system obtained is , temporary coordinate system Around Axis rotation Available i Section 1 Coordinate System According to the segmented linkage design, i The sections should fall under o i-1 xi-1 Axis and In the plane spanned by the axis, the plane normal vector is recorded as ,like Figure 8 As shown, Normal vector around axis Rotate to The angle of the axis is recorded as angle .

[0096] Figure 8 FIG. 4 shows a schematic diagram of a plane where a robot arm segment is located and a corresponding normal vector according to an exemplary embodiment of the present application, such as Figure 8 As shown, three adjacent linked robotic arm segments are shown, each linked robotic arm segment includes four connecting rods of equal length, and the sections of different robotic arm segments fall on different circles.

[0097] No. i The center of the circle where the segment is located is recorded as c i , the radius of the circle is r i Among them, i The normal vector of the plane where the segment is located is perpendicular to the paper surface and points downward. As mentioned above, since each robot segment consists of 4 sections, i-1 The coordinate system of the robot arm segment x Normal vector around axis Rotate to i The coordinate system of the robot arm segment x Axis Angle , according to the segmented linkage design, Figure 8 Middle i The arc spanned by the segment linkage segment is .

[0098] In this embodiment, using i The radius of the circle where the segment universal joint is located r i The reciprocal of represents the bending degree of the linkage robot segment, that is, r i The smaller the value, the greater the curvature of the segment. i The arc angle spanned by a segment can also describe the curvature of the segment, that is, The larger it is, the greater the curvature of the segment.

[0099] According to the embodiment of the present application, for describing i The curvature index of the bending degree of the segment robot arm is shown in formula (4) or (5).

[0100] (4)

[0101] (5)

[0102] in, For the i The curvature index of each robot segment, r i For the i The radius of the plane circle on which the robot arm segments are located.

[0103] According to the three cosine theorem, the angle The value is shown in formula (6).

[0104] (6)

[0105] According to the relationship between the exterior angle of a regular polygon and the central angle of a circle, we can know that i The radius of the circle on which the universal joints of the robot arm segments are located r i As shown in formula (7).

[0106] (7)

[0107] in, l i For the i The length of the middle section of the robot arm segment.

[0108] In step S305, the normal vector of the plane where each robot arm segment is located is calculated.

[0109] In the segment coordinate system In the coordinate axis vector go through Figure 7 Shown Y P After rotation, that is, the robot arm i Segment rotation angle , and then rotate the angle , and its direction is shown in formula (8).

[0110] (8)

[0111] in, Indicates the rotation angle around the z axis , Indicates the rotation angle around the y axis Thus, the normal vector is calculated As shown in formula (9).

[0112] (9)

[0113] in, Vector modulus operation.

[0114] Similarly, the robot arm i Passage , After rotation, the normal vector As shown in formula (10).

[0115] (10)

[0116] In step S307, the torsion index of each robot arm segment is calculated according to the calculated normal vector of the plane where each robot arm segment is located.

[0117] According to the embodiments of the present application, i+1 Section 1 i The degree of the plane where the segment lies is given by the torsion index given by formula (11): describe.

[0118] (11)

[0119] according to Figure 3 In the embodiment shown, the bending degree within the segment of the segmented linkage robot arm can be determined by the curvature index shown in formula (4) or formula (5), and the bending degree between segments can be determined by the torsion index shown in formula (11). The above two indexes jointly measure the arm shape of the robot arm in space.

[0120] In a specific embodiment, for a specific task, other constraints on the robot arm, such as the robot arm needs to work in a small space, a certain section is in a fixed plane, etc., can be uniformly described as an equality constraint as shown in formula (12) or an inequality constraint as shown in formula (13).

[0121] (12)

[0122] (13)

[0123] in, Ceq Represents the equation, Cie Represents an inequality.

[0124] Therefore, the robot arm type planning problem can be described as an optimization problem in the standard form as shown in formula (14):

[0125] (14)

[0126] in, Respectively The maximum and minimum values ​​obtained, Respectively The maximum and minimum values ​​obtained.

[0127] In some embodiments, the optimization problem described in formula (14) can be solved by a variety of methods, including but not limited to solving it by using a genetic algorithm or using an optimization algorithm such as sequential quadratic programming.

[0128] According to the embodiments of the present application, the proposed optimization framework for arm shape planning of a segmented linkage robotic arm is utilized to provide standardized prevention measures for solving the arm shape planning problem of the segmented linkage robotic arm, thereby providing feasibility for the engineering application of the segmented linkage robotic arm in different application environments.

[0129] In order to verify the rationality and effectiveness of the arm shape planning method of the present application, in this embodiment, a segmented linkage robot arm is used to perform arm shape planning simulation. In this simulation, the segmented linkage robot arm has 8 segments, each with 4 sections, each section is 0.1m long, and the rotation angle constraints in both directions of the universal joint are 60deg. The homogeneous matrix of the robot reference coordinate system relative to the world coordinate system is as shown in formula (15).

[0130] (15)

[0131] First, verify the arm bending formula (3) It plays an important role in optimizing the local and overall arm shape. Consider the end position of the robot arm as , the end of the robot is oriented in the direction of the x-axis of the world system, ignoring the constraints of formula (12) and formula (13), the parameters in formula (3) are set as: , Take respectively:

[0132] (a) ;

[0133] (b) ;

[0134] (c) ;

[0135] (d) .

[0136] The corresponding robot arm type planning results are as follows Figure 9a , 9b , 9c and 9d, the circles in the figure represent the universal joints between the connecting rods, the line segments between the circles represent the connecting rods, different colors distinguish different segments, and the five-pointed star represents the installation location of the actuator at the end of the robot arm.

[0137] Depend on Figure 9a , 9b , 9c and 9d, it can be seen that when a certain design weight When the value is small, the linkage section will have a greater degree of bending, and the linkage section will be more "soft". On the contrary, when the design weight of a section is When the value is larger, the linkage section bends less and appears "hard". Therefore, by using the preset arm bending weight value, arm curvature weight and / or arm torsion weight, according to the embodiment of the present application, a mechanical arm shape that meets the task objectives can be obtained.

[0138] Fig.10a , 10b 10c and 10d show schematic diagrams of an arm type planning method applied to a T-shaped working area effect optimization process according to an exemplary embodiment of the present application. Given the T-shaped working scene shown in FIG10 , the robot arm needs to pass through the slit to detect the space inside the T-shaped area. Fig.10b , 10c and 10d are the arm shape optimization results obtained according to the embodiment of the present application. The obstacle constraints of the scene in the figure are described by formula (12) and formula (13). If the 4th, 5th and 6th sections of the robot arm need to be kept in the XY plane of the world system, then the value of formula (12) can be designed as shown in formula (16).

[0139] (16)

[0140] in, Respectively represent the normal vectors of the planes where the 4th, 5th and 6th segments of the robot are located, represents the normal vector of the XY plane of the world system. Formula (13) can be designed as

[0141]

[0142] In the formula, Indicates the position of each joint of the robot arm in the world system, Indicates the T-shaped workspace boundary.

[0143] It can be seen that the arm shape planning results given in this application meet the strict environmental constraints. After passing through the slit, the arm shape is smooth, and the detection of the internal space of the T-shaped area is completed without the entire arm touching the surrounding obstacles.

[0144] It should be noted that formula (16) is only an example and cannot be understood as a limitation of the present application. Those skilled in the art can determine the specific expressions of formulas (12) and (13) according to the constraints.

[0145] The above mainly introduces the embodiments of the present application from the perspective of the method. Those skilled in the art should easily appreciate that, in combination with the operations or steps of each example described in the embodiments disclosed herein, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Those skilled in the art can use different ways to implement the described functions for each specific operation or method, and such implementation should not be considered to be beyond the scope of the present application.

[0146] The following describes the device embodiments of the present application. For details not described in the device embodiments of the present application, reference can be made to the method embodiments of the present application.

[0147] Fig.11 A block diagram of an arm type planning device for a segmented linkage mechanical arm according to an exemplary embodiment of the present application is shown. Fig.11 The arm shape planning device shown includes a segmentation unit 1101 and an arm shape bending degree calculation unit 1103. The segment weight preset unit 1101 is used to preset the arm shape segment weight for each arm shape segment of the segmented linkage manipulator; the arm shape bending degree calculation unit 1103 is used to determine the rotation angle of each arm shape segment of the plurality of arm shapes according to the end posture of the segmented linkage manipulator and the preset bending weight, so as to minimize the arm shape bending degree of the segmented linkage manipulator.

[0148] Fig.12 An electronic device according to an exemplary embodiment of the present application is shown. Fig.12 The electronic device 200 according to this embodiment of the present application is described. Fig.12 The electronic device 200 shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0149] like Fig.12 As shown, the electronic device 200 is in the form of a general computing device. The components of the electronic device 200 may include, but are not limited to: at least one processing unit 210, at least one storage unit 220, a bus 230 connecting different system components (including the storage unit 220 and the processing unit 210), a display unit 240, etc.

[0150] The storage unit stores program codes, which can be executed by the processing unit 210, so that the processing unit 210 executes the methods described in this specification according to various exemplary embodiments of the present application. For example, the processing unit 210 can execute the following: Figure 1 The method shown in .

[0151] The storage unit 220 may include a readable medium in the form of a volatile storage unit, such as a random access storage unit (RAM) 2201 and / or a cache storage unit 2202 , and may further include a read-only storage unit (ROM) 2203 .

[0152] The storage unit 220 may also include a program / utility 2204 having a set (at least one) of program modules 2205, such program modules 2205 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0153] Bus 230 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, an accelerated graphics port, a processing unit, or a local bus using any of a variety of bus architectures.

[0154] The electronic device 200 may also communicate with one or more external devices 300 (e.g., keyboards, pointing devices, Bluetooth devices, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 200, and / or may communicate with any device that enables the electronic device 200 to communicate with one or more other computing devices (e.g., routers, modems, etc.). Such communication may be performed via an input / output (I / O) interface 250. In addition, the electronic device 200 may also communicate with one or more networks (e.g., a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) via a network adapter 260. The network adapter 260 may communicate with other modules of the electronic device 200 via a bus 230. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 200, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0155] Through the description of the above implementation methods, it is easy for those skilled in the art to understand that the example implementation methods described here can be implemented by software, or by combining software with necessary hardware. The technical solution according to the implementation method of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, including several instructions to enable a computing device (which can be a personal computer, a server, or a network device, etc.) to execute the above method according to the implementation method of the present application.

[0156] The software product can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can be, for example, but not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0157] Computer readable storage media may include data signals propagated in baseband or as part of a carrier wave, wherein readable program codes are carried. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, device, or device. The program codes contained on the readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0158] Program code for performing the operations of the present application may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, as a separate software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0159] The computer-readable medium carries one or more programs. When the one or more programs are executed by a device, the computer-readable medium implements the aforementioned functions.

[0160] Those skilled in the art will appreciate that the above modules can be distributed in the device according to the description of the embodiment, or can be changed accordingly and only used in one or more devices different from the embodiment. The modules of the above embodiments can be combined into one module, or further divided into multiple sub-modules.

[0161] According to an embodiment of the present application, a computer program is provided, including a computer program or an instruction. When the computer program or the instruction is executed by a processor, the method described above can be executed.

[0162] The embodiments of the present application are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and its core idea of ​​the present application. At the same time, changes or deformations made by those skilled in the art based on the ideas of the present application, the specific implementation methods and the scope of application of the present application, all belong to the scope of protection of the present application. In summary, the content of this specification should not be construed as a limitation on the present application.

Claims

1. A method for arm shape planning of a segmented linkage robot arm, characterized in that: The segmented linkage mechanical arm includes a plurality of mechanical arm segments, and the arm shape planning method includes: Presetting a robot segment weight for each robot segment of the segmented linkage robot arm; Determining the rotation angle of each of the plurality of robot arm segments according to the end posture of the segmented linkage robot arm and a preset bending weight, so as to minimize the arm bending degree of the segmented linkage robot arm; The arm bending degree of the segmented linkage mechanical arm is determined by an arm bending index, and the arm bending index is determined by an arm curvature index and an arm torsion index; the arm bending index is expressed by the following formula: in, represents the arm curvature index of the segmented linkage robotic arm, Represents the arm type torsion index of the segmented linkage mechanical arm; The arm segment weight includes an arm bending weight value, an arm curvature weight, and an arm torsion weight. The arm curvature index is determined by the following formula: ； The arm torsion index is determined by the following formula: ； in, and They are used to measure the degree of bending within the entire robot arm segment and the degree of distortion between segments. and They are used to measure the differences in curvature and torsion between segments of the entire robotic arm. , , , , , , For the i The curvature index of each robot segment, For the i The torsion index of each robot segment, m is the total number of robot segments in the segmented linkage robot, is the preset arm bending weight value, For the i The arm curvature weight of each robot segment, No. i The arm torsion weight of each robot segment.

2. The arm shape planning method according to claim 1, characterized in that: The coordinate system of each of the robotic arm segments includes a first coordinate axis, a second coordinate axis, and a third coordinate axis, and the first coordinate axis, the second coordinate axis, and the third coordinate axis are perpendicular to each other, the first coordinate axis is parallel to the elongation direction of the robotic arm segment, and the rotation angle of each of the robotic arm segments includes a first rotation angle and a second rotation angle, wherein determining the rotation angle of each of the plurality of robotic arm segments includes: Rotate each of the robot arm segments from the initial coordinate system around the direction indicated by the third coordinate axis to obtain a first temporary coordinate system and the first rotation angle; Each of the robot arm segments is rotated from the first temporary coordinate system around the direction indicated by the second coordinate axis to obtain the second rotation angle.

3. The arm shape planning method according to claim 2, characterized in that: Each robotic arm segment includes a plurality of sections, and the curvature index of each robotic arm segment is as follows: ,or ， in, For the i The curvature index of each robot segment, r i For the i The radius of the plane circle where the robot arm segments are located, , l i For the i The length of the middle section of the robot arm segment, For the i-1 The coordinate system of the robot arm segment x Axis around i The normal vector of the plane where the first robot segment is located is rotated to the i The coordinate system of the first segment of the robot arm segment x The angle of the axis, , For the i The first rotation angle of each robot segment, For the i The second rotation angle of each robot segment.

4. The arm shape planning method according to claim 3, characterized in that: The torsion index of each of the robotic arm segments is as follows: ， in, is the torsion index of each of the robot arm segments, For the i The normal vector of the plane on which the robot segment lies, For the i+1 The normal vector of the plane on which the robot segment lies.

5. The arm shape planning method according to claim 4, characterized in that: No. i The normal vector of the plane where each robot segment is located is shown as follows: or in, For the i The normal vector of the plane on which the robot segment lies, For the i The first rotation angle of each robot segment, For the i The second rotation angle of each robot segment.

6. The arm shape planning method according to claim 5, characterized in that: When the arm bending index of the segmented linkage mechanical arm is the smallest, the constraints satisfied include: The end position and the rotation angle of each robot arm segment satisfy the robot arm kinematic constraints; The segmented linkage mechanical arm works in a preset working space; The first rotation angle is within a preset threshold range; and / or The second rotation angle is within a preset threshold range.

7. An arm type planning device for a segmented linkage mechanical arm, characterized in that: Used to execute the arm shape planning method according to any one of claims 1 to 6, the arm shape planning device comprises: A segment weight preset unit, used for presetting a robot arm segment weight for each robot arm segment of the segmented linkage robot arm; The arm shape planning calculation unit is used to determine the rotation angle of each of the multiple arm segments according to the end posture of the segmented linkage robot arm and the preset bending weight, so as to minimize the arm shape bending degree of the segmented linkage robot arm.

8. An electronic device comprising: processor; as well as A memory storing a computer program, which, when executed by the processor, enables the processor to execute the arm shape planning method as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having computer-readable instructions stored thereon, which, when executed by a processor, causes the processor to execute the arm shape planning method as described in any one of claims 1-6.

Images