Robot joint space angle acquisition method and path planning method and device

Abstract

The application provides a robot joint space angle acquisition method and a path planning method and device, wherein a plurality of sets of robot external shaft joint space angles are obtained according to prior joint movement ranges of the robot external shaft, then the plurality of sets of robot external shaft joint space angles are substituted into forward kinematics of the robot external shaft, a pose of a base of a robot mechanical arm in a world coordinate system corresponding to each set of joint space angles is obtained, then a plurality of sets of poses of a robot mechanical arm end in a robot base coordinate system are obtained according to prior poses of the robot mechanical arm end in the world coordinate system, the plurality of sets of poses of the robot mechanical arm end in the robot base coordinate system are substituted into inverse kinematics of the robot mechanical arm, and the plurality of sets of corresponding robot joint space angles are obtained in combination with corresponding robot mechanical arm joint space angles and robot external shaft joint space angles. The application solves the problems that the prior art cannot fully utilize the redundancy characteristics of a redundant robot, and the success rate of path planning is low.

Description

Technical Field

[0001] This invention relates to the field of robot control, and in particular to a method and device for obtaining robot joint spatial angles and for path planning. Background Technology

[0002] There are two common strategies for motion planning in existing welding robots with overhead and ground tracks. One strategy treats the ground and overhead tracks as one set of kinematic models, and the 6-axis manipulator at the end effector as another set of kinematic models, with each set of kinematic models performing motion planning separately. The other strategy treats the ground track, overhead track, and 6-axis manipulator as a robot with joint redundancy, i.e., a robot with joint space degrees of freedom greater than task space degrees of freedom, and then uses theories related to redundant robots for motion planning.

[0003] However, when planning the ground track, overhead track, and robotic arm separately, it is difficult to determine the values ​​of the overhead track and the ground track. When treating the ground track, overhead track, and robotic arm as a robot with joint redundancy and using the numerical solution of inverse kinematics related to redundant robots to solve the joint space angles and planning, it will be affected by problems such as initial values, joint constraints, and singular configurations, resulting in a low planning success rate.

[0004] Therefore, how to improve the existing technology's inability to fully utilize the redundancy characteristics of redundant robots and the low success rate of path planning are technical problems that urgently need to be solved in this field. Summary of the Invention

[0005] Based on this, the purpose of this application is to provide a method and device for obtaining the spatial angle of a robot joint with a ceiling track and a ground track, and to plan the path, so as to solve at least one of the technical problems mentioned in the background art.

[0006] In a first aspect, this application provides a method for obtaining the spatial angles of a robot joint with a ceiling track and a ground track, including:

[0007] S1: Based on the prior joint movement range of the robot's external axis, the joint movement range of the robot's external axis is discretized to obtain several sets of robot external axis joint spatial angles.

[0008] S2: Substitute several sets of robot external axis joint spatial angles into the robot external axis positive kinematics to obtain the pose of the robot external axis end in the world coordinate system corresponding to each set of robot external axis joint spatial angles. This is regarded as the pose of the robot arm base in the world coordinate system corresponding to each set of joint spatial angles.

[0009] S3: Based on the poses of the base of several robot arms in the world coordinate system and the prior poses of the robot arm end effector in the world coordinate system, obtain the poses of several robot arm end effectors in the robot base coordinate system.

[0010] S4: Substitute the poses of each group of robot arm ends in the robot base coordinate system into the robot arm inverse kinematics to obtain several groups of robot arm joint space angles corresponding to the poses of each group of robot arm ends in the robot base coordinate system. Combine the corresponding robot arm joint space angles with the robot external axis joint space angles to obtain several sets of corresponding robot joint space angles.

[0011] Furthermore, the positive kinematics of the robot's external axis are:

[0012]

[0013] in, This represents the pose of the robot's external axis end effector in the world coordinate system. Let be the transformation matrix between the x-th joint and the (x-1)-th joint of the robot's external axis, where represents the spatial angle of the x-th joint of the robot's external axis, and 1 <x<m。

[0014] Furthermore, the steps of obtaining several sets of robot arm end-effector poses in the robot base coordinate system also include:

[0015] When a welding torch is attached to the end effector of the robotic arm, the end effector of the welding torch is the actual end effector of the robotic arm:

[0016]

[0017] in, This represents the pose of the robot's welding torch tip in the world coordinate system. This represents the transformation matrix from the end of the welding torch to the end flange of the robot arm. This represents the pose of the robot arm's end effector in the world coordinate system.

[0018] Furthermore, by combining the joint space angles of the corresponding robotic arm and the joint space angles of the robot's external axis, several specific steps are taken to obtain the robot's joint space angles, including:

[0019] Iterate through the pose of the first joint of each group of robot arm joint space angles and the end pose of the robot's external axis, and determine whether the poses are the same. If they are the same, combine the corresponding robot arm joint space angles and the robot's external axis joint space angles, and iterate until all complete robot joint space angles are obtained.

[0020] Furthermore, after obtaining several sets of corresponding joint space angles for the robotic arm, the process also includes:

[0021] S44: Determine whether the angle of each joint of the robotic arm is greater than the operable angle range of the corresponding joint. If it is greater, then discard the spatial angle of that group of joints; if it is not greater, then proceed to step S45.

[0022] S45: Determine whether the robotic arm collides with obstacles in the environment when it is at each set of joint space angles. If so, discard that set of angles. If not, obtain the appropriate joint space angle.

[0023] Secondly, this application provides a path planning method for a robot, including:

[0024] P1: Install a welding torch and several identification sensors at the end of the welding robot;

[0025] P2: Control the robotic arm to move to the prior weld position, obtain the pose of the robotic arm end in the world coordinate system when the end of the robotic arm is located at the current weld start coordinate, and obtain several sets of joint space angles corresponding to the current weld start according to any of the above methods.

[0026] P3: Obtain the joint space angles when the end of the robotic arm is in a safe position. Based on several sets of joint space angles corresponding to the current weld start point, obtain several corresponding joint space paths between the safe position and the current weld start point, and obtain the optimal joint space path based on preset conditions.

[0027] P4: Obtain the prior weld direction, control the end of the robotic arm to run along the current weld start point and weld end point, obtain the pose of the current weld start point in the world coordinate system and several sampled path points between the current weld start point and weld end point, and obtain the joint space path between the current weld start point and weld end point.

[0028] P5: Based on the prior weld position, determine whether there are welds without a planned path. If yes, proceed to step P6; otherwise, complete the path planning.

[0029] P6: Based on the prior weld position, obtain the sampling path point between the current weld start point and the next weld start point to obtain the joint space path between the two points, and take the next weld start point as the current weld start point, then return to step P5.

[0030] Furthermore, the step of obtaining the optimal joint space path based on preset conditions includes:

[0031] Obtain the robot's maneuverability and joint movement corresponding to each joint spatial path;

[0032] The path with the smallest weighted combination of robot maneuverability and joint movement among several sets of spatial joint paths is considered the final determined joint spatial path.

[0033] Furthermore, the pose of the current weld start point in the world coordinate system and several sampled path points between the current weld start point and the weld end point are obtained to obtain the joint space path between the current weld start point and the weld end point, including:

[0034] The robotic arm is controlled to move along the direction of the prior weld seam. The weld seam is sampled at set sampling intervals by the identification sensor to obtain the pose of the current weld seam starting point in the world coordinate system and several sampling path points between the current weld seam starting point and the weld seam ending point.

[0035] Substitute the pose of the current weld start point in the world coordinate system into any of the above methods to obtain several sets of joint space angles corresponding to the current weld start point.

[0036] The path with the smallest weighted combination of robot maneuverability and joint movement among several sets of spatial joint paths is considered the final determined joint spatial path.

[0037] Furthermore, the method is characterized by further comprising:

[0038] Obtain the current joint space angle of the robot at any position;

[0039] Based on the current joint space angle of the robot at any position and the joint space angle of the robot arm end in a safe position, several corresponding joint space paths are obtained between the safe position and the initial weld start point.

[0040] The path with the smallest weighted combination of robot maneuverability and joint movement among several sets of spatial joint paths is considered the final determined joint spatial path.

[0041] Thirdly, this application also provides a terminal device, including a memory and a processor; the memory stores program code that can be executed by the processor; the program code is used to execute the robot joint space angle acquisition method with ceiling and ground tracks described in the first aspect and / or the robot path planning method described in the second aspect. Attached Figure Description

[0042] Figure 1 This is a flowchart of a method for obtaining the joint spatial angle of a robot with overhead and ground tracks according to an embodiment of the present invention.

[0043] Figure 2 This is a flowchart of a robot path planning method according to an embodiment of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that if the embodiments of the present invention involve directional indications, such as up, down, left, right, front, back, etc., these directional indications are only used to explain the relative positional relationships and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly. Furthermore, if the embodiments of the present invention involve descriptions such as "first," "second," "S1," "S2," "step one," "step two," etc., these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance, or implicitly indicating the number of technical features indicated or the order of method execution. Those skilled in the art will understand that anything that does not violate the inventive concept and is within the scope of the present invention should be included in the protection scope of the present invention.

[0046] like Figure 1 As shown, this invention provides a method for obtaining the spatial angle of a robot joint with a ceiling track and a ground track, comprising:

[0047] S1: Based on the prior joint movement range of the robot's external axis, the joint movement range of the robot's external axis is discretized to obtain several sets of robot external axis joint spatial angles.

[0048] Specifically, the a priori range of motion of the joints can be obtained directly from the robot's technical specifications or the robot control software, or it can be obtained by a person skilled in the art by manually controlling the robot's external axes in advance and recording their range of motion.

[0049] More specifically, the movement range of each joint of the robot's external axis can be discretized based on the prior joint movement range of the robot's external axis, and the movement range of each joint of the robot's external axis can be divided into several parts to obtain several sets of corresponding robot external axis joint spatial angles; the specific number of sets of robot external axis joint spatial angles can be selected, but is not limited to, arbitrarily determined by those skilled in the art; preferably, the movement range of each joint of the robot's external axis is divided based on the minimum accuracy of the robot's external axis joint motor.

[0050] Further preferred, but not limited to, setting the number of external axes of the robot to m and the number of joints of the robot arm to n, the joint spatial angles of the robot can be expressed as Equation 1-1:

[0051] q = [q0,...,q m-1,q m ,...,q m+n-1 ]1-1

[0052] Where q is the joint space angle of the robot, q i Let be the joint space angle of the i-th joint of the robot, 0 < i <m+n。

[0053] For example, optionally but not limited to dividing the range of motion of each joint on the robot's external axis into h equal parts based on the prior range of motion of the joints on the robot's external axis. j To obtain h j Candidate angle values ​​for the range of motion, (where j = 0 ~ m-1, h j (This represents the number of divisions into which the range of motion of each joint on the robot's external axis is divided), thus obtaining... Candidate angle values ​​for the robot's external axis, i.e. The joint space angles of the robot's external axes; preset constraints, including joint limits, collision detection, maximum speed and maximum acceleration, etc.; it is worth noting that the preset constraints can be selected, but are not limited to, being read directly from the robot's specifications, joint sensors, collision detection devices, controllers, and other components.

[0054] S2: Substitute several sets of robot external axis joint spatial angles into the robot external axis positive kinematics to obtain the pose of the robot external axis end in the world coordinate system corresponding to each set of robot external axis joint spatial angles. This is regarded as the pose of the robot arm base in the world coordinate system corresponding to each set of joint spatial angles.

[0055] Specifically, but not limited to, substituting the spatial angles of several sets of robot external axis joints obtained in step S1 into the positive kinematics of the robot external axis, we can obtain the pose of the robot external axis end in the world coordinate system corresponding to each set of robot external axis joint spatial angles. Since the robot external axis end is connected to the base of the robot arm, we can also obtain the pose of the robot arm base in the world coordinate system corresponding to each set of joint spatial angles.

[0056] For example, optionally but not limited to, substituting the spatial angles of each group of robot external axis joints into the positive kinematics of the robot's external axis, one can obtain the pose of the robot's external axis end effector in the world coordinate system corresponding to the spatial angles of each group of robot external axis joints. Since the end of the robot's external axis is connected to the base of the robot arm, the poses of several sets of robot arm bases in the world coordinate system are obtained. in,

[0057] Preferably, the positive kinematics of the robot's external axis can be, but is not limited to, represented as 2-1:

[0058]

[0059] in, This refers to the pose of the robot's external axis end effector in the world coordinate system (equivalent to the pose of the robot arm's base in the world coordinate system). Let be the transformation matrix between the x-th joint and the (x-1)-th joint of the robot's external axis, where represents the spatial angle of the x-th joint of the robot's external axis, and 1 <x<m。

[0060] S3: Based on the poses of the robot arm base in the world coordinate system and the prior poses of the robot arm end effector in the world coordinate system, obtain the poses of the robot arm end effector in the robot base coordinate system; the prior poses can be obtained from the robot CAD model, but are not limited to those obtained from the robot CAD model.

[0061] Specifically, the prior pose of the robot arm's end effector in the world coordinate system can be obtained, but is not limited to, from the robot's CAD model. Then combine the results obtained in step S2 The pose of the robot arm's base in the world coordinate system corresponding to the joint space angles. The pose of the robot arm's end effector in the robot's base coordinate system can then be calculated. in

[0062] More preferably, when a welding torch is mounted on the end effector of the robotic arm, the end effector of the welding torch is the actual end effector of the robotic arm. Therefore, the pose of the welding torch end effector in the world coordinate system can be calculated according to Equation 3-1:

[0063]

[0064] in, This represents the pose of the robot's welding torch tip in the world coordinate system. This represents the transformation matrix from the end of the welding torch to the end flange of the robot arm. This represents the pose of the robot arm's end effector in the world coordinate system.

[0065] S4: Substitute the poses of each group of robot arm ends in the robot base coordinate system into the inverse kinematics of the robot arm to obtain the joint space angles of several groups of robot arms corresponding to the poses of each group of robot arm ends in the robot base coordinate system. Combine the joint space angles of the corresponding robot arms with the joint space angles of the robot's external axis joints to obtain several sets of corresponding robot joint space angles.

[0066] Specifically, but not limited to, substituting the poses of each set of robot arm end caps in the robot base coordinate system obtained in step S3 into the robot inverse kinematics, several sets of corresponding robot arm joint space angles can be obtained. Since the pose of the robot arm base is the pose of the robot's external axis end caps, combining the joint space angles of each set of robot arm end caps with the corresponding robot external axis joint space angles can yield several complete sets of robot joint space angles.

[0067] Preferably, by combining the joint space angles of the corresponding robot arm and the joint space angles of the robot's external axis, several sets of corresponding robot joint space angles are obtained, which may include, but are not limited to:

[0068] S41: Iterate through the pose of the first joint of each group of robot arm joint space angles and the end pose of the robot's external axis, and determine whether the poses are the same. If they are, combine the corresponding robot arm joint space angles and the robot's external axis joint space angles, and iterate until all complete robot joint space angles are obtained.

[0069] For example, as shown in step S3, a set of joint angles of the robot's external axes can yield the pose of the robot's external axis end in the world coordinate system. Since the end of the robot's external axis is connected to the robot's base, the pose of the robot arm's base in the world coordinate system is obtained. Based on the pose of the robot arm's base in the world coordinate system Given the prior pose of the robot arm's end effector in the world coordinate system, the pose of the robot arm's end effector in the robot's base coordinate system can be calculated. Then the pose of the robot arm's end effector in the robot's base coordinate system can be determined. Substituting the inverse kinematics of the robotic arm yields k solutions, i.e., k sets of joint space angles for the robotic arm. When k is not zero, it can be considered that several valid sets of joint space angles for the robotic arm have been obtained. Combining these sets of joint space angles with the joint angles of the robot's external axes from the first step yields several complete sets of robot joint angles. Repeating the above steps until the joint angles of all robot external axes have been calculated yields all complete robot joint space angles. Further preferably, after obtaining several sets of corresponding robot joint space angles, optional, but not limited to, further steps include:

[0070] S45: Determine whether the angle of each joint of the robotic arm is greater than the operable angle range of the corresponding joint. If it is greater, then discard the spatial angle of that group of joints; if it is not greater, then proceed to step S46.

[0071] Specifically, the operable angle range of each joint of the robot arm can be obtained, but is not limited to, through the robot's technical specifications and / or the robot control system. All obtained joint spatial angles of the robot arm are compared with their corresponding operable angle ranges. If a joint spatial angle of the robot arm is greater than its corresponding operable angle range, it means that the joint spatial angle of the robot arm only exists in theory and cannot be realized in actual operation; therefore, this joint spatial angle needs to be discarded. If the joint spatial angle of the robot arm is not greater than its corresponding operable angle range, it means that the joint spatial angle of the robot arm can be realized in actual operation, and this joint spatial angle can be further tested.

[0072] S46: Determine whether the robotic arm collides with obstacles in the environment when it is at each set of joint space angles. If so, discard that set of angles. If not, obtain the appropriate joint space angle.

[0073] Specifically, but not limited to, based on the robot's 3D model, the robot's motion trajectory at each set of joint space angles is simulated to determine whether the robot collides with obstacles in the surrounding environment and / or the working environment, and whether the robot's various components interfere with each other. If a collision or interference is detected, it means that the set of joint space angles cannot be realized and needs to be removed. Then, several sets of robot joint space angles can be obtained.

[0074] This embodiment presents a method for obtaining the joint spatial angles of a robot with overhead and ground tracks. By discretizing the joint movement range of the robot's external axes based on their prior joint ranges, several sets of joint spatial angles are obtained. This allows the robot's overhead and ground tracks to be considered as part of its joints, thus incorporating them into the robot's motion planning process. This enables the robot to fully utilize the redundancy of the overhead and ground tracks during motion planning, improving the robot's degrees of freedom during operation. Then, these sets of joint spatial angles are substituted into the forward kinematics of the robot's external axes to obtain the pose of the robot's external axis end effector in the world coordinate system corresponding to each set of joint spatial angles. This pose is considered as the pose of the robot arm's base in the world coordinate system corresponding to each set of joint spatial angles. Finally, based on these poses of the robot arm's base in the world coordinate system... Based on the prior poses of the robot arm's end effector in the world coordinate system, several sets of poses of the robot arm's end effector in the robot's base coordinate system are obtained. Finally, these poses are substituted into the inverse kinematics of the robot arm to obtain several sets of joint space angles corresponding to the poses of the robot arm's end effector in the robot's base coordinate system. Combining these joint space angles with the joint space angles of the robot's external axis, several sets of corresponding robot joint space angles are obtained. Several possible sets of joint space angles for both the robot arm and the robot's external axis are then obtained. Finally, these achievable sets of joint space angles are combined to obtain several complete sets of achievable robot joint space angles. All joint space angles that cannot be achieved due to joint limitations or collisions are eliminated, improving the success rate of path planning. This solves the problems of existing technologies failing to fully utilize the redundancy characteristics of redundant robots and having low path planning success rates.

[0075] like Figure 2 As shown, the present invention provides a path planning method for a robot, comprising:

[0076] P1: Install a welding torch and several identification sensors at the end of the welding robot;

[0077] Specifically, the welding robot may include, but is not limited to, a multi-axis robotic arm with overhead and ground rails, preferably with the overhead and ground rails considered as the robot's external axes; the identification sensors may include, but are not limited to, 2D cameras, laser rangefinders, lidar, laser trackers, coordinate measuring machines, and other measuring devices commonly used to measure and sense the position of objects; it is worth noting that the installation position must allow the identification sensors to clearly identify the workpiece surface, while maintaining a set safe distance between the robot and the workpiece surface to avoid collisions between the welding torch and the workpiece surface that could cause damage; the safe distance may be set arbitrarily by those skilled in the art.

[0078] Preferably, the identification sensor consists of a 2D camera and a laser rangefinder. The 2D camera acquires the relative position of the weld seam and the robot end effector on the same plane, while the laser rangefinder acquires the relative distance between the plane where the weld seam is located and the end effector of the welding torch.

[0079] P2: Control the robotic arm to move to the prior weld position, obtain the pose of the robotic arm end in the world coordinate system when it is located at the current weld start coordinate, and obtain several sets of joint space angles corresponding to the current weld start according to any of the above methods; the prior weld position is pre-marked by a person skilled in the art or obtained according to the workpiece model or pre-set by a person skilled in the art.

[0080] Specifically, since the welding robot needs to replenish welding wire during the welding process, it is preferable to set a safe position so that the welding robot can replenish welding wire at will. This can be selected, but not limited to, obtaining the prior weld position. Any weld start point can be selected as the current weld start point. The robotic arm is controlled to move to the prior weld position, and the pose of the current weld start point coordinates in the world coordinate system is obtained. The pose of the current weld start point coordinates in the world coordinate system is then substituted into the joint space angle acquisition method to obtain several sets of joint space angles corresponding to the current weld start point.

[0081] P3: Obtain the joint space angles when the end of the robotic arm is in a safe position. Based on several sets of joint space angles corresponding to the current weld start point, obtain several corresponding joint space paths between the safe position and the current weld start point, and obtain the optimal joint space path based on preset conditions.

[0082] Specifically, it is optional, but not limited to, obtaining the joint space angle when the end of the robot arm is in a safe position. Preferably, it is to obtain a smooth joint space angle trajectory between the joint space angle when the end of the robot arm is in a safe position and several sets of joint space angles corresponding to the current weld start point according to the joint space planning method. This will yield several corresponding joint space paths between the safe position and the initial weld start point. Finally, the optimal joint space path among all joint space paths is obtained according to preset conditions.

[0083] Preferably, the step of obtaining the optimal joint space path based on preset conditions may include, but is not limited to, the following:

[0084] P31: Obtain the robot's operability and joint movement corresponding to each joint spatial path;

[0085] Specifically, the robot's maneuverability corresponding to each joint spatial path can be obtained using kinematic maneuverability analysis methods, but is not limited to this. Then, the joint movement corresponding to each joint spatial path can be obtained using joint movement analysis methods, but is not limited to this. Kinematic maneuverability analysis methods can include, but are not limited to, commonly used calculation methods such as condition number-based methods, characteristic ellipsoid volume-based methods, minimum singular value-based methods, weighted condition number-based methods, and task-based maneuverability methods. Joint movement analysis methods can include, but are not limited to, commonly used joint movement analysis methods such as cumulative angle method, maximum joint spatial angle method, weighted angle method, Euclidean norm method, and maximum joint velocity method.

[0086] P32: Among several sets of spatial joint paths, the path with the smallest weighted combination of robot operability and joint movement is considered the final determined joint spatial path.

[0087] Specifically, the sorting can be, but is not limited to, sorting by the degree of robot operability and / or the amount of joint movement and / or a weighted combination of both, to obtain the joint space path with the maximum operability and / or the minimum amount of joint movement, i.e., the optimal joint space path; preferably, the specific sorting method can be arbitrarily set by those skilled in the art based on the site environment and production process and other conditions.

[0088] P4: Obtain the prior weld direction, control the end effector of the robotic arm to run along the current weld start point and weld end point, obtain several sampling path points between the current weld start point and weld end point, and obtain the joint space path between the current weld start point and weld end point; the prior weld direction is pre-marked by a person skilled in the art or obtained according to the workpiece model or pre-set by a person skilled in the art.

[0089] Specifically, the robot arm can be moved along the direction of the prior weld by means of a sensor that samples the weld at set intervals to obtain several sampling path points between the current weld start point and the weld end point. The pose of the current weld start point in the world coordinate system is substituted into the joint space angle acquisition method to obtain k sets of corresponding joint space angles. Then, the k sets of joint space angles are used as initial values ​​to perform parallel calculations on the subsequent weld path points to obtain k sets of spatial joint paths. Preferably, the k sets of spatial joint paths are sorted according to a weighted combination of robot operability and joint movement to obtain the corresponding optimal joint space path. The sampling interval can be set arbitrarily by those skilled in the art.

[0090] Preferably, the relative position of the weld and the robot end effector on the same plane is obtained by a 2D camera, and sampling is performed in the weld area at set intervals until the end of the weld. At the same time, the distance between the end of the weld and the robot arm is obtained by a laser rangefinder, and the specific coordinates of each weld path point in the world coordinate system and the pose of the current weld start point in the world coordinate system are obtained.

[0091] P5: Based on the prior weld position, determine whether there are welds without a planned path. If yes, proceed to step P6; otherwise, complete the path planning.

[0092] P6: Based on the prior weld position, obtain the sampling path point between the current weld start point and the next weld start point to obtain the joint space path between the two points, and take the next weld start point as the current weld start point, and return to step P5;

[0093] Specifically, based on the prior weld position, it is determined whether there are welds that have not been scanned and have their paths planned. If so, based on the prior weld position, the robotic arm is controlled to obtain the sampling path points between the current weld start point and the next weld start point, and the joint space path between the two points is obtained according to the joint space path planning method. The next weld start point is taken as the current weld start point, and the determination of whether there are welds with unplanned paths is continued until the path planning of all welds is completed.

[0094] Preferably, since the welding wire carried by the robot during the welding process may be insufficient to support the robot in completing the welding work of the current weld, the path planning method of the welding robot further includes:

[0095] P7: Obtain the current joint angle of the robot at any position, and get the optimal joint space path from any position to a safe position.

[0096] Specifically, the current joint space angle of the robot at any position can be obtained by using the motors carried by the robot itself. According to the joint space planning method, a smooth joint space angle trajectory between the joint space angle of the robot arm end in a safe position and the current joint space angle of the robot at any position can be obtained. Several corresponding joint space paths can be obtained between the safe position and the initial weld start point. Finally, the path with the smallest weighted combination of robot operability and joint movement among several sets of spatial joint paths is regarded as the final determined joint space path.

[0097] On the other hand, the present invention also provides a computer storage medium storing executable program code; the executable program code is used to execute any of the above-mentioned methods for obtaining the spatial angles of robot joints with overhead and ground tracks or for robot path planning.

[0098] On the other hand, the present invention also provides a terminal device, including a memory and a processor; the memory stores program code that can be executed by the processor; the program code is used to execute any of the above-mentioned methods for obtaining the spatial angles of robot joints with overhead and ground tracks or for robot path planning.

[0099] For example, the program code can be divided into one or more modules / units, which are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the program code in the terminal device.

[0100] The terminal device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the terminal device may also include input / output devices, network access devices, buses, etc.

[0101] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0102] The memory can be an internal storage unit of the terminal device, such as a hard drive or RAM. The memory can also be an external storage device of the terminal device, such as a plug-in hard drive, SmartMedia Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory can include both internal and external storage units of the terminal device. The memory is used to store the program code and other programs and data required by the terminal device. The memory can also be used to temporarily store data that has been output or will be output.

[0103] The aforementioned terminal device is created based on the above-mentioned method for obtaining the spatial angle of robot joints with overhead and ground tracks and the path planning method. Its technical function and beneficial effects will not be elaborated here. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for obtaining the spatial angle of a robot joint with a ceiling track and a ground track, characterized in that, include: S1: Based on the prior joint movement range of the robot's external axis, the joint movement range of the robot's external axis is discretized to obtain several sets of robot external axis joint spatial angles. S2: Substitute several sets of robot external axis joint spatial angles into the robot external axis positive kinematics to obtain the pose of the robot external axis end in the world coordinate system corresponding to each set of robot external axis joint spatial angles. This is regarded as the pose of the robot arm base in the world coordinate system corresponding to each set of joint spatial angles. S3: Based on the poses of the base of several robot arms in the world coordinate system and the prior poses of the robot arm end effector in the world coordinate system, obtain the poses of several robot arm end effectors in the robot base coordinate system. S4: Substitute the poses of the end effectors of each group of robot arms in the robot base coordinate system into the inverse kinematics of the robot arm to obtain the joint space angles of several groups of robot arms corresponding to the poses of the end effectors of each group of robot arms in the robot base coordinate system. Combine the joint space angles of the corresponding robot arms with the joint space angles of the robot's external axis to obtain several groups of robot joint space angles.

2. The method according to claim 1, characterized in that, The robot's external axis positive kinematics are: in, This represents the pose of the robot's external axis end effector in the world coordinate system. Let be the transformation matrix between the x-th joint and the (x-1)-th joint of the robot's external axis, where represents the spatial angle of the x-th joint of the robot's external axis, and 1 <x<m。 3. The method according to claim 1, characterized in that, The steps for obtaining several sets of robot arm end-effector poses in the robot base coordinate system also include: When a welding torch is attached to the end effector of the robotic arm, the end effector of the welding torch is the actual end effector of the robotic arm: in, This represents the pose of the robot's welding torch tip in the world coordinate system. This represents the transformation matrix from the end of the welding torch to the end flange of the robot arm. This represents the pose of the robot arm's end effector in the world coordinate system.

4. The method according to claim 1, characterized in that, The specific steps for obtaining several sets of robot joint space angles by combining the joint space angles of the corresponding robot arm and the robot's external axis joint space angles include: Iterate through the pose of the first joint of each group of robot arm joint space angles and the end pose of the robot's external axis, and determine whether the poses are the same. If they are the same, combine the corresponding robot arm joint space angles and the robot's external axis joint space angles, and iterate until all complete robot joint space angles are obtained.

5. The method according to claim 4, characterized in that, After obtaining several sets of corresponding joint space angles for the robotic arm, the following is also included: S45: Determine whether the angle of each joint of the robotic arm is greater than the operable angle range of the corresponding joint. If it is greater, then discard the spatial angle of that group of joints; if it is not greater, then proceed to step S46. S46: Determine whether the robotic arm collides with obstacles in the environment when it is at each set of joint space angles. If so, discard that set of angles. If not, obtain the appropriate joint space angle.

6. A path planning method for a robot, characterized in that, include: P1: Install a welding torch and several identification sensors at the end of the welding robot; P2: Control the robotic arm to move to the prior weld position, obtain the pose of the robotic arm end in the world coordinate system when the end of the robotic arm is located at the current weld start coordinate, and obtain several sets of joint space angles corresponding to the current weld start according to any of the above methods. P3: Obtain the joint space angles when the end of the robotic arm is in a safe position. Based on several sets of joint space angles corresponding to the current weld start point, obtain several corresponding joint space paths between the safe position and the current weld start point, and obtain the optimal joint space path based on preset conditions. P4: Obtain the prior weld direction, control the end of the robotic arm to run along the current weld start point and weld end point, obtain the pose of the current weld start point in the world coordinate system and several sampled path points between the current weld start point and weld end point, and obtain the joint space path between the current weld start point and weld end point. P5: Based on the prior weld position, determine whether there are welds without a planned path. If yes, proceed to step P6; otherwise, complete the path planning. P6: Based on the prior weld position, obtain the sampling path point between the current weld start point and the next weld start point to obtain the joint space path between the two points, and take the next weld start point as the current weld start point, then return to step P5.

7. The method according to claim 6, characterized in that, The steps for obtaining the optimal joint space path based on preset conditions include: Obtain the robot's maneuverability and joint movement corresponding to each joint spatial path; The path with the smallest weighted combination of robot maneuverability and joint movement among several sets of spatial joint paths is considered the final determined joint spatial path.

8. The method according to claim 6, characterized in that, Obtain the pose of the current weld start point in the world coordinate system and several sampled path points between the current weld start point and the weld end point to obtain the joint space path between the current weld start point and the weld end point, including: The robotic arm is controlled to move along the direction of the prior weld seam. The weld seam is sampled at set sampling intervals by the identification sensor to obtain the pose of the current weld seam starting point in the world coordinate system and several sampling path points between the current weld seam starting point and the weld seam ending point. Substitute the pose of the current weld start point in the world coordinate system into any of the above methods to obtain several sets of joint space angles corresponding to the current weld start point. The path with the smallest weighted combination of robot maneuverability and joint movement among several sets of spatial joint paths is considered the final determined joint spatial path.

9. The method according to claim 6, characterized in that, The method further includes: Obtain the current joint space angle of the robot at any position; Based on the current joint space angle of the robot at any position and the joint space angle of the robot arm end effector at a safe position, several corresponding joint space paths are obtained between the safe position and the initial weld start point. The path with the smallest weighted combination of robot maneuverability and joint movement among several sets of spatial joint paths is considered the final determined joint spatial path.

10. A terminal device, characterized in that, It includes a memory and a processor; the memory stores program code that can be executed by the processor; the program code is used to execute the method for obtaining the joint space angle of a robot with a ceiling track and a ground track as described in any one of claims 1-5 or the path planning method of a robot as described in any one of claims 6-9.

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