CN116619381A - Obstacle avoidance path planning method for industrial robot - Google Patents
Obstacle avoidance path planning method for industrial robot Download PDFInfo
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- 238000005070 sampling Methods 0.000 claims abstract description 83
- 238000013519 translation Methods 0.000 claims abstract description 82
- 238000003466 welding Methods 0.000 claims abstract description 53
- 230000008569 process Effects 0.000 claims abstract description 10
- 238000003860 storage Methods 0.000 claims description 14
- 238000001514 detection method Methods 0.000 claims description 13
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1656—Programme controls characterised by programming, planning systems for manipulators
- B25J9/1664—Programme controls characterised by programming, planning systems for manipulators characterised by motion, path, trajectory planning
- B25J9/1666—Avoiding collision or forbidden zones
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K37/00—Auxiliary devices or processes, not specially adapted to a procedure covered by only one of the preceding main groups
- B23K37/02—Carriages for supporting the welding or cutting element
- B23K37/0258—Electric supply or control circuits therefor
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1679—Programme controls characterised by the tasks executed
- B25J9/1682—Dual arm manipulator; Coordination of several manipulators
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
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Abstract
The invention relates to the technical field of industrial robots, in particular to an obstacle avoidance path planning method of an industrial robot, which comprises the following steps: determining a configuration space of a welding task; determining a starting point and an ending point of a path planning task; according to the first external translation axis parameter and the second external translation axis parameter of the starting point and the ending point, combining a preset expansion amount, and determining sampling ranges of the first external translation axis parameter and the second external translation axis parameter of the sampling point in the path planning process; and respectively constructing node trees by taking the starting point and the ending point as root nodes, and expanding the two node trees by performing point searching until the two node trees meet. The method can realize path planning of the double-welding robot with the portal frame external device in high-dimensional freedom degree, and has good planning efficiency and stability.
Description
Technical Field
The embodiment of the invention relates to the technical field of industrial robots, in particular to an obstacle avoidance path planning method for an industrial robot.
Background
The robot path planning problem refers to finding a collision-free path of an industrial robot from a given initial state (or starting point) to a target state (or ending point) in a configuration space that satisfies constraints. In general, the shorter the path length, the shorter the planning time is, which means that the better the path planning method is, and the method is more suitable for engineering application.
At present, an industrial robot path planning task for welding is mainly completed through manual teaching, programming efficiency is low in a scene of flexibly placing workpieces, quality cannot be guaranteed, and particularly for a welding robot additionally provided with an external device, the difficulty of teaching programming is further improved due to the improvement of the degree of freedom.
Disclosure of Invention
Based on the problem of low programming efficiency in high-dimensional degree-of-freedom industrial robot path planning teaching, the embodiment of the invention provides an industrial robot obstacle avoidance path planning method, electronic equipment and a storage medium, which can automatically realize high-dimensional degree-of-freedom double-welded robot path planning with a portal frame external device and have good planning efficiency and stability.
In a first aspect, an embodiment of the present invention provides a method for planning an obstacle avoidance path of an industrial robot, including:
the double-welder robot is suitable for a double-welder robot with a portal frame external device; the double-welding robot comprises two mechanical arms provided with welding guns respectively, and the portal frame external device comprises a first external translation shaft, a second external translation shaft and an external rotation shaft, wherein the first external translation shaft and the second external translation shaft respectively move along the x direction and the y direction in a horizontal plane, and the external rotation shaft rotates around the z axis in the vertical direction; the double-welding robot is arranged on the external device of the portal frame, can change the overall pose under the drive of the external device of the portal frame, and can independently change the poses of all joints of the two mechanical arms;
the method comprises the following steps:
determining a configuration space of a welding task;
determining a starting point and an ending point of a path planning task; the starting point and the ending point comprise a plurality of parameters which are used for representing the joint postures of the two mechanical arms and the current state of the external device of the portal frame;
according to the first external translation axis parameter and the second external translation axis parameter of the starting point and the ending point, combining a preset expansion amount, and determining sampling ranges of the first external translation axis parameter and the second external translation axis parameter of the sampling point in the path planning process;
respectively constructing node trees by taking the starting point and the ending point as root nodes, and expanding the two node trees by performing point searching until the two node trees meet;
wherein, for any node tree, performing the point search includes:
determining a root node and a target point;
generating and determining sampling points for indicating the expansion direction according to the configuration space of the welding task and the determined sampling range;
based on the determined sampling point and the preset expansion step length, a new node x is expanded for the current node tree new And for the new node x new Performing collision detection, if passing, continuing to execute subsequent steps, and if not, deleting the new node x new Returning to the step of determining the sampling point;
based on new node x new And a preset first radius R 1 Determining a new node x new Is a set of neighboring points; the nodes in the adjacent point set are taken from the current node tree and are combined with the new node x new Not exceeding the first radius R 1 ；
Based on new node x new And a preset second radius R 2 Judging whether a new node x exists in the adjacent point set new Not exceeding the second radius R 2 If not, continuing to execute the subsequent steps, if so, dividing the new node x new Returning to the step of determining the sampling point; the second radius R 2 Smaller than the first radius R 1 ；
New node x new Adding the current node tree, and performing reselection parent node and rerouting operations on the new nodePerforming; the method comprises the steps of carrying out a first treatment on the surface of the
Performing collision detection again, if the current node tree passes, updating the current node tree, and if the current node tree does not pass, deleting a new node x from the current node tree new And then returning to the step of determining the sampling point.
Optionally, the generating and determining the sampling point for indicating the extension direction includes:
randomly generating N sampling points according to a preset target deflection probability; n is a positive integer not less than 3;
and respectively calculating the offset degree of each sampling point relative to the connecting line of the root node and the target point aiming at the two dimensions of the first external translation axis parameter and the second external translation axis parameter, and selecting the sampling point with the minimum offset degree.
Optionally, calculating the offset degree of the sampling point relative to the connection line between the root node and the target point, by adopting the following method:
calculating a sampling point x for two dimensions of the first external translation axis parameter and the second external translation axis parameter rand The corresponding Cos value is expressed as:
wherein e 1,s And e 2,s 、e 1,e And e 2,e E 1,r And e 2,r Respectively represent a root node, a target point and a sampling point x rand The first external translation axis parameter and the second external translation axis parameter of (2) are used for representing norm calculation;
the selecting the sampling point with the minimum offset degree comprises the following steps:
and selecting the sampling point with the maximum corresponding Cos value.
Optionally, the determining the configuration space of the welding task includes:
determining a working space which can be reached by welding based on the portal frame external device and the working parameters of the double-welding robot;
establishing an obstacle model and determining an obstacle space; the obstacle model includes a double welding robot model and a welding workpiece model.
Optionally, the preset expansion amount is determined according to the height of the welding workpiece.
Optionally, the mechanical arm is a six-axis mechanical arm.
Alternatively, two nodes x a And x b The distance between them is calculated by the following formula:
wherein θ i,a And theta i,b Respectively represent node x a And node x b I=1,..6 represents the joint numbers of one arm in the double-welded robot, i=7,..12 represents the joint numbers of the other arm, e,) 1,a And e 1,b 、e 2,a And e 2,b E 3,a And e 3,b Respectively represent node x a And node x b Is used to calculate the absolute value.
Optionally, the second radius R 2 For the first radius R 1 1/5 to 1/4 of the total weight of the product.
In a second aspect, an embodiment of the present invention further provides an electronic device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the method described in any embodiment of the present specification is implemented.
In a third aspect, embodiments of the present invention further provide a computer readable storage medium having stored thereon a computer program which, when executed in a computer, causes the computer to perform a method according to any of the embodiments of the present specification.
The embodiment of the invention provides an obstacle avoidance path planning method, electronic equipment and a storage medium for an industrial robot, which limit the sampling range of external axis parameters in sampling points according to the characteristics of a portal frame external device and the starting point and the ending point of path planning so as to improve the path planning quality and shorten the processing time. The invention can automatically realize the path planning of the double-welding robot with the portal frame external device in high-dimensional freedom degree, and has better planning efficiency and stability.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for planning obstacle avoidance paths of an industrial robot according to an embodiment of the present invention;
FIG. 2 is a schematic diagram illustrating a determination method for limiting a nearest node according to an embodiment of the invention;
FIG. 3 (a) is a node tree diagram that does not limit the nearest nodes;
FIG. 3 (b) is a node tree diagram limiting the nearest nodes;
fig. 4 (a) shows a top view of scenario 1 for a welding test;
fig. 4 (b) shows a top view of scenario 2 for a welding test;
FIG. 5 (a) shows path length results for 20 independent runs of multiple path planning methods in scenario 1;
FIG. 5 (b) shows the path length results obtained by running multiple path planning methods independently 20 times in scenario 2;
FIG. 6 (a) shows the time results taken for multiple path planning methods to run independently 20 times in scenario 1;
fig. 6 (b) shows the time results taken for the various path planning methods to run independently 20 times in scenario 2.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present invention are within the scope of protection of the present invention.
As described above, the path planning task of the industrial robot for welding is mainly completed through manual teaching, in a scene where workpieces are flexibly placed, the programming efficiency is low, the quality cannot be ensured, and particularly for a welding robot with an external device, the difficulty of teaching programming is further improved due to the improvement of the degree of freedom. For the double-welding robot with the portal frame external device, if the mechanical arm with the welding gun has six-dimensional degrees of freedom, the whole double-welding robot with the portal frame external device can reach fifteen-dimensional degrees of freedom, and at the moment, a teaching programming or conventional path planning method is used, so that a high-quality path is difficult to quickly search. In view of this, the present invention provides an improved bidirectional RRT method for implementing obstacle avoidance path planning for an industrial robot, where the present invention extends from two directions of a start point and an end point simultaneously, limits a sampling range according to a gantry system structure, improves path quality, reduces unnecessary path searching, optimizes searching time by limiting a nearest node policy, improves searching efficiency, and finally implements welding robot path planning with high-dimensional degree of freedom.
Specific implementations of the above concepts are described below.
Referring to fig. 1, an embodiment of the present invention provides an industrial robot obstacle avoidance path planning method, which is applicable to a double welder robot with a portal frame external device;
the double-welding robot comprises two mechanical arms provided with welding guns respectively, and the portal frame external device comprises a first external translation shaft, a second external translation shaft and an external rotation shaft, wherein the first external translation shaft and the second external translation shaft respectively move along the x direction and the y direction in a horizontal plane, and the external rotation shaft rotates around the z axis in the vertical direction; the nesting relationship of the three external shafts (namely, a first external translation shaft, a second external translation shaft and an external rotation shaft) can be that the first external translation shaft is movably arranged on the portal frame and can move along the x direction relative to the portal frame, the second external translation shaft is movably arranged on the first external translation shaft and can move along the y direction relative to the first external translation shaft, and the external rotation shaft is rotatably arranged on the second external translation shaft and can rotate relative to the second external translation shaft; in other embodiments, other nesting methods may be used to ensure that the gantry external device can provide three additional degrees of freedom for the dual welder robot;
the double-welding robot is arranged on the external device of the portal frame, can change the overall pose under the drive of the external device of the portal frame, and can independently change the poses of all joints of the two mechanical arms; the single mechanical arm is preferably a six-axis mechanical arm, and at the moment, the two mechanical arms of the double-welder robot share twelve-dimensional degrees of freedom, and the two mechanical arms can reach fifteen-dimensional degrees of freedom in addition to the external device of the portal frame.
The obstacle avoidance path planning method of the industrial robot comprises the following steps:
step 100, determining a configuration space of a welding task;
102, determining a starting point and an ending point of a path planning task; the starting point and the ending point comprise a plurality of parameters which are used for representing the joint postures of the two mechanical arms and the current state (namely three external shaft parameters) of the external device of the portal frame;
104, determining sampling ranges of the first external translation axis parameter and the second external translation axis parameter of the sampling point in the path planning process according to the first external translation axis parameter and the second external translation axis parameter of the starting point and the ending point and in combination with a preset expansion amount;
the first external translation axis parameter and the second external translation axis parameter with initial points are respectively e 1,i And e 2,i The first external translation axis parameter and the second external translation axis parameter of the termination point are respectively e 1,t And e 2,t The preset expansion amount comprises the x directionThe expansion amount ex and the y-direction expansion amount ey, the sampling range of the first external translation axis of the sampling point in the path planning process is min (e 1,i ，e 1,t ) Ex to max (e 1,i ，e 1,t ) +ex, the sampling range of the second external translation axis of the sampling point is min (e 2,i ，e 2,t ) -ey to max (e 2,i ，e 2,t )+ey；
Step 106, respectively constructing node trees by taking the starting point and the ending point as root nodes, and expanding the two node trees by performing point searching until the two node trees meet;
wherein, for any node tree, performing the point search includes:
106-0, determining a root node and a target point;
for the node tree constructed by taking the starting point as a root node, the target point is the ending point, and for the node tree constructed by taking the ending point as a root node, the target point is the starting point; the starting point and the ending point are expanded simultaneously, so that the duration of searching a path is shortened;
step 106-2, generating and determining sampling points for indicating the expansion direction according to the configuration space of the welding task and the determined sampling range;
step 106-4, expanding a new node x for the current node tree based on the determined sampling point and the preset expansion step length new And for the new node x new Performing collision detection, if passing, continuing to execute subsequent steps, and if not, deleting the new node x new Returning to the step of determining the sampling point, namely returning to the step 106-2 to obtain a new sampling point;
step 106-6, based on the new node x new And a preset first radius R 1 Determining a new node x new Is a set of neighboring points; the nodes in the adjacent point set are taken from the current node tree, and the nodes in the adjacent point set are connected with the new node x new Not exceeding the first radius R 1 ；
Step 106-8, based on the new node x new And a preset second radius R 2 Judgment of the instituteIn the set of neighboring points, whether there is a new node x new Not exceeding the second radius R 2 If not, continuing to execute the subsequent steps, if so, dividing the new node x new Returning to the step of determining the sampling point, namely returning to the step 106-2 to obtain a new sampling point; the second radius R 2 Smaller than the first radius R 1 ；
Step 106-10, new node x new Adding the current node tree, and executing the operations of parent node reselection and rerouting on the new node; the method comprises the steps of carrying out a first treatment on the surface of the
The specific process of this part can refer to RRT method, and will not be further described herein;
step 106-12, collision detection is performed again, if the current node tree passes, the current node tree is updated, and if the current node tree does not pass, a new node x is deleted from the current node tree new Thereafter, the step of determining the sampling point is returned, i.e., step 106-2, to obtain a new sampling point.
The embodiment of the invention considers that the external device (or the portal frame system structure) of the portal frame is provided with three external shafts, wherein the movement range of two translation shafts (namely a first external translation shaft and a second external translation shaft) is larger, if sampling is carried out in all strokes, the path quality is poor, so that the sampling range of external shaft parameters in sampling points is limited, the path planning quality is improved, and the processing time is shortened.
Meanwhile, considering that the double-welding robot with a portal frame external device has high degree of freedom, more parameters of each path point, larger configuration space of welding tasks and unstable obstacle environment, in order to reduce the burden of sampling and collision detection in a sparse obstacle environment and improve the processing efficiency, as shown in fig. 2, the invention introduces the limit of the nearest node, when a new node x is new When the distance from the node in the current node tree is too small (i.e., there is a node, new node x new From which the distance d is smaller than the second radius R 2 ) Then the new node x new Deleting and searching new nodes again, so that the node distribution in the node tree is more uniform, and the exploration of unknown space in the sparse barrier environment is facilitated, therebyCollision detection of the similar areas is avoided, and calculation time is saved. Fig. 3 (a) and 3 (b) show the use of RRT method from root node x start To target point x end Without limiting the nearest nodes and the node tree schematic obtained by limiting the nearest nodes, the black boxes in fig. 3 (a) and 3 (b) represent obstacles, and it can be seen that by limiting the nearest nodes, a more sparse node tree can be obtained. Second radius R 2 Too small a setting, possibly with less effect on making the nodes evenly distributed, with limited effect on improving the path, a second radius R 2 Setting too large may result in difficulty in searching for a suitable new node, more preferably the second radius R 2 For the first radius R 1 1/5 to 1/4 of the total weight of the product.
Optionally, for step 100, further comprising:
determining a working space which can be reached by welding based on the portal frame external device and the working parameters of the double-welding robot;
establishing an obstacle model and determining an obstacle space; the obstacle model includes a double welding robot model and a welding workpiece model. If other obstacles are present, the model thereof is also determined at this step.
After determining the working space where the weld is available, the obstacle space is removed and the remaining space can be considered free space.
Optionally, for step 104, a preset expansion amount is determined according to the height of the welded workpiece.
Step 104 expands a certain range outwards based on the first external translation axis parameter and the second external translation axis parameter of the starting point and the ending point, which considers that the blocking of the welding workpiece in the height direction may cause the reduction of the success rate of path planning, so as to effectively bypass the welding workpiece and enable a feasible welding path. Preferably, the expansion amount is not less than 1 time of the height of the welding workpiece.
Optionally, in step 106-2, determining the sampling point further includes:
106-2-0, randomly generating N sampling points according to a preset target deflection probability;
wherein N is a positive integer not less than 3; n is preferably 3 to 5;
the sampling points comprise a plurality of parameters which are used for representing the joint postures of the two mechanical arms and the current state of the external device of the portal frame, wherein the parameters of the first external translation axis and the parameters of the second external translation axis do not exceed the determined sampling range;
specifically, the target deflection probability is set as P, a random number P epsilon (0, 1) is generated, if P is less than or equal to P, the target point is a generated sampling point, if P is more than P, the random point generated randomly is a sampling point, and the P is preferably 0.1;
step 106-2-2, calculating the offset degree of each sampling point relative to the connection line between the root node and the target point for the two dimensions of the first external translation axis parameter and the second external translation axis parameter, and selecting the sampling point with the minimum offset degree.
In consideration of the structural characteristics of a portal frame external device, the movement range of two translation axes is larger, the influence is larger, and in order to reduce the length of an integral welding path, the invention adopts a mode of sampling for a plurality of times in one search aiming at parameters corresponding to the two translation axes, and selects a sampling point with shorter translation axis movement to indicate an expansion direction, so that a search path is projected on a horizontal plane formed by connecting lines of the starting point and the ending point in the x direction and the y direction as much as possible, and the planned path has a trend of approaching the connecting lines of the starting point and the ending point, thereby effectively avoiding the problems of detour of a robot in a free space, overlarge offset and the like.
Further, in step 106-2-2, the offset degree of the sampling point with respect to the connection line between the root node and the target point is calculated by the following method:
calculating a sampling point x for two dimensions of the first external translation axis parameter and the second external translation axis parameter rand A corresponding Cos value; sampling point x rand The corresponding Cos value expression is:
wherein e 1,s And e 2,s 、e 1,e And e 2,e E 1,r And e 2,r Respectively represent a root node, a target point and a sampling point x rand A first external translation axis parameter and a second external translation axis parameter, e 1,s And e 2,s A first external translation axis parameter and a second external translation axis parameter, e, respectively representing the root node of the node tree 1,r And e 2,r Respectively represent sampling points x rand A first external translation axis parameter and a second external translation axis parameter, e 1,e And e 2,e A first external translation axis parameter and a second external translation axis parameter respectively representing target points of the node tree, (e) 1,e -e 1,s ,e 2,e -e 2,s ) Representing two-dimensional vectors formed by connecting the root node with the target point aiming at two dimensions of the first external translation axis parameter and the second external translation axis parameter, wherein the I represents norm calculation;
the selecting the sampling point with the minimum offset degree comprises the following steps:
and selecting the sampling point with the maximum corresponding Cos value.
The greater the Cos value, which means that the sampling point is closer to the connection line between the root node and the target point (i.e., the connection line between the start point and the end point), the above embodiment can rapidly screen out the sampling points closer to the connection line between the root node and the target point from among the plurality of sampling points by calculating the Cos value corresponding to the sampling point only in two dimensions of the first external translation axis parameter and the second external translation axis parameter. For gantry external devices, this approach minimizes movement of the first and second external translation axes that move in the x and y directions, respectively, in the horizontal plane.
Optionally, in step 106, two nodes x a And x b The distance between them can be calculated by the following formula:
wherein θ i,a And theta i,b Respectively represent node x a And node x b I=1,..6 represents the joint numbers of one arm in the double-welded robot, i=7,..12 represents the joint numbers of the other arm, e,) 1,a And e 1,b 、e 2,a And e 2,b E 3,a And e 3,b Respectively represent node x a And node x b Is used to calculate the absolute value.
The above embodiment provides how to calculate two nodes x for the case where the robot is a six-axis robot a And x b In other embodiments, if the mechanical arm is a four-axis mechanical arm, the corresponding calculation formula should be adjusted, the value range and the specific corresponding meaning of i should be changed, for the four-axis mechanical arm, i is greater than or equal to 1 and less than or equal to 8,i =1.
Step 106, performing collision detection after expanding the new node and adding the new node into the node tree to ensure that the searched path can realize collision-free welding. Preferably, the double-welder robot and the welding workpiece are processed by a hierarchical bounding box method, so that more efficient collision detection can be realized, for example, the mechanical arm joints are respectively segmented into 1, 2 and 3 level bounding boxes, and the detection process is executed in a synchronous descending mode for the hierarchical bounding boxes constructed by the two binary trees. In other embodiments, collision detection may be accomplished in other ways, which are not further defined herein.
The invention also selects four existing robot obstacle avoidance path planning methods of RRT, RRT-connect and IB-RRT as comparison, tests are carried out by using a scene 1 shown in fig. 4 (a) and a scene 2 shown in fig. 4 (b) to verify the comprehensive performance of the industrial robot obstacle avoidance path planning method (the method is short) provided by the invention, fig. 5 (a) shows the maximum value (max), the minimum value (min) and the average value (avg) of the path lengths obtained by independently running the method in the scene 1 for 20 times, fig. 5 (b) shows the maximum value, the minimum value and the average value of the path lengths obtained by independently running the method in the scene 2 for 20 times, fig. 6 (a) shows the maximum value, the minimum value and the average value of the path lengths obtained by independently running the method in the scene 2, and fig. 6 (a) shows the maximum value, the maximum value and the average value (RRT) respectively shown in the scene 1, the maximum value (min) and the average value (avg) respectively in the scene 1, the maximum value (RRT) and the average value (average value) shown in the scene 6 (b) respectively, and the average value (RRT) respectively shown in the scene 6 (5, and the average value (5) respectively). As can be seen from fig. 5 (a) to fig. 6 (b), in the paths obtained by the method provided by the invention, the average value, the maximum value and the minimum value of the path length are all optimal, and meanwhile, the time consumption is also shortest, so that the path planning method passing through the method provided by the invention has higher searching efficiency and stable searching quality, and is beneficial to practical engineering application.
The embodiment of the invention also provides electronic equipment, which comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method for planning the obstacle avoidance path of the industrial robot in any embodiment of the invention is realized.
The embodiment of the invention also provides a computer readable storage medium, and the computer readable storage medium is stored with a computer program, when the computer program is executed by a processor, the processor is caused to execute the obstacle avoidance path planning method of the industrial robot in any embodiment of the invention.
Specifically, a system or apparatus provided with a storage medium on which a software program code realizing the functions of any of the above embodiments is stored, and a computer (or CPU or MPU) of the system or apparatus may be caused to read out and execute the program code stored in the storage medium.
In this case, the program code itself read from the storage medium may realize the functions of any of the above-described embodiments, and thus the program code and the storage medium storing the program code form part of the present invention.
Examples of the storage medium for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (e.g., CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a nonvolatile memory card, and a ROM. Alternatively, the program code may be downloaded from a server computer by a communication network.
Further, it should be apparent that the functions of any of the above-described embodiments may be implemented not only by executing the program code read out by the computer, but also by causing an operating system or the like operating on the computer to perform part or all of the actual operations based on the instructions of the program code.
Further, it is understood that the program code read out by the storage medium is written into a memory provided in an expansion board inserted into a computer or into a memory provided in an expansion module connected to the computer, and then a CPU or the like mounted on the expansion board or the expansion module is caused to perform part and all of actual operations based on instructions of the program code, thereby realizing the functions of any of the above embodiments.
The embodiments of the invention have at least the following beneficial effects:
1. in one embodiment of the invention, an obstacle avoidance path planning method for an industrial robot is provided, the method limits the sampling range of nodes by analyzing a portal frame system, improves the planning quality, limits the nearest nodes in the sampling process, achieves the purpose of sparse sampling, and further reduces the planning time; the method has good pertinence to the portal frame system, can effectively solve the problem of path planning in the sparse environment of the obstacle, effectively shortens the time consumption of searching, and solves the problem of path planning of the portal frame robot system with high-dimensional freedom degree, thereby reducing the labor cost, improving the automation and intelligent degree of the production process, and being more suitable for engineering application;
2. in one embodiment of the invention, an obstacle avoidance path planning method for an industrial robot is provided, the method utilizes a sampling pool mechanism to sample for a plurality of times in one search, selects nodes with shorter external translation axis movement, shortens the path length, improves the path quality, and has better adaptability according to the selection basis, wherein the selection basis can be correspondingly adjusted according to scenes;
3. in one embodiment of the invention, an obstacle avoidance path planning method for an industrial robot is provided, and the method carries out a hierarchical bounding box method on a robot joint and a workpiece, so that a more efficient collision detection flow is realized through processing.
It is noted that relational terms such as first and second, and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above method embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, where the program, when executed, performs steps including the above method embodiments; and the aforementioned storage medium includes: various media in which program code may be stored, such as ROM, RAM, magnetic or optical disks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The obstacle avoidance path planning method for the industrial robot is characterized by being suitable for a double-welder robot with a portal frame external device; the double-welding robot comprises two mechanical arms provided with welding guns respectively, and the portal frame external device comprises a first external translation shaft, a second external translation shaft and an external rotation shaft, wherein the first external translation shaft and the second external translation shaft respectively move along the x direction and the y direction in a horizontal plane, and the external rotation shaft rotates around the z axis in the vertical direction; the double-welding robot is arranged on the external device of the portal frame, can change the overall pose under the drive of the external device of the portal frame, and can independently change the poses of all joints of the two mechanical arms;
the method comprises the following steps:
determining a configuration space of a welding task;
determining a starting point and an ending point of a path planning task; the starting point and the ending point comprise a plurality of parameters which are used for representing the joint postures of the two mechanical arms and the current state of the external device of the portal frame;
according to the first external translation axis parameter and the second external translation axis parameter of the starting point and the ending point, combining a preset expansion amount, and determining sampling ranges of the first external translation axis parameter and the second external translation axis parameter of the sampling point in the path planning process;
respectively constructing node trees by taking the starting point and the ending point as root nodes, and expanding the two node trees by performing point searching until the two node trees meet;
wherein, for any node tree, performing the point search includes:
determining a root node and a target point;
generating and determining sampling points for indicating the expansion direction according to the configuration space of the welding task and the determined sampling range;
based on the determined sampling point and the preset expansion step length, a new node x is expanded for the current node tree new And for the new node x new Performing collision detection, if passing, continuing to execute subsequent steps, and if not, deleting the new node x new Returning to the step of determining the sampling point;
based on new node x new And a preset first radius R 1 Determining a new node x new Is a set of neighboring points; the nodes in the adjacent point set are taken from the current node tree and are combined with the new node x new Not exceeding the first radius R 1 ；
Based on new node x new And a preset second radius R 2 Judging whether a new node x exists in the adjacent point set new Not exceeding the second radius R 2 If not, continuing to execute the subsequent steps, if so, dividing the new node x new Returning to the step of determining the sampling point; the second radius R 2 Smaller than the first radius R 1 ；
New node x new Adding the current node tree, and executing the operations of parent node reselection and rerouting on the new node; the method comprises the steps of carrying out a first treatment on the surface of the
Performing collision detection again, if the current node tree passes, updating the current node tree, and if the current node tree does not pass, deleting a new node x from the current node tree new And then returning to the step of determining the sampling point.
2. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the generating and determining the sampling point for indicating the expansion direction comprises the following steps:
randomly generating N sampling points according to a preset target deflection probability; n is a positive integer not less than 3;
and respectively calculating the offset degree of each sampling point relative to the connecting line of the root node and the target point aiming at the two dimensions of the first external translation axis parameter and the second external translation axis parameter, and selecting the sampling point with the minimum offset degree.
3. The method of claim 2, wherein the step of determining the position of the substrate comprises,
calculating the offset degree of the sampling point relative to the connecting line of the root node and the target point by adopting the following mode:
calculating a sampling point x for two dimensions of the first external translation axis parameter and the second external translation axis parameter rand Corresponding CosThe value, expression is:
wherein e 1,s And e 2,s 、e 1,e And e 2,e E 1,r And e 2,r Respectively represent a root node, a target point and a sampling point x rand The first external translation axis parameter and the second external translation axis parameter of (2) are used for representing norm calculation;
the selecting the sampling point with the minimum offset degree comprises the following steps:
and selecting the sampling point with the maximum corresponding Cos value.
4. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the determining the configuration space of the welding task comprises the following steps:
determining a working space which can be reached by welding based on the portal frame external device and the working parameters of the double-welding robot;
establishing an obstacle model and determining an obstacle space; the obstacle model includes a double welding robot model and a welding workpiece model.
5. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the preset expansion amount is determined according to the height of the welding workpiece.
6. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the mechanical arm is a six-axis mechanical arm.
7. The method of claim 6, wherein the step of providing the first layer comprises,
two nodes x a And x b The distance between them is calculated by the following formula:
wherein θ i,a And theta i,b Respectively represent node x a And node x b I=1,..6 represents the joint numbers of one arm in the double-welded robot, i=7,..12 represents the joint numbers of the other arm, e,) 1,a And e 1,b 、e 2,a And e 2,b E 3,a And e 3,b Respectively represent node x a And node x b Is used to calculate the absolute value.
8. The method of claim 1, wherein the step of determining the position of the substrate comprises,
the second radius R 2 For the first radius R 1 1/5 to 1/4 of the total weight of the product.
9. An electronic device comprising a memory and a processor, the memory having stored therein a computer program, characterized in that the processor, when executing the computer program, implements the method according to any of claims 1-8.
10. A storage medium having stored thereon a computer program, which, when executed in a computer, causes the computer to perform the method of any of claims 1-8.
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| CN116749150B (en) * | 2023-08-21 | 2023-12-12 | 南京埃斯顿自动化股份有限公司 | Motion planning method for multi-axis robot system, electronic equipment and medium |
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