CN112060093B - Path planning method for overhead line maintenance mechanical arm - Google Patents
Path planning method for overhead line maintenance mechanical arm Download PDFInfo
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- CN112060093B CN112060093B CN202010944366.XA CN202010944366A CN112060093B CN 112060093 B CN112060093 B CN 112060093B CN 202010944366 A CN202010944366 A CN 202010944366A CN 112060093 B CN112060093 B CN 112060093B
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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
Abstract
The invention discloses a path planning method for an overhead line maintenance mechanical arm, which comprises the steps of firstly obtaining obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and end point position information of the tail end of the mechanical arm, carrying out non-collision path planning aiming at the tail end position of the mechanical arm in a Cartesian space according to the obstacle information, the operation degree threshold value, the initial position information of the tail end of the mechanical arm and the end point position information of the tail end of the mechanical arm, giving a feasible path of the tail end of the mechanical arm, avoiding generating a large number of invalid sampling points, reducing calculated amount, then carrying out secondary path planning until the feasible paths are connected, and completing the whole path planning of the tail end of the mechanical arm.
Description
Technical Field
The invention relates to the field of electric power, in particular to a path planning method for an overhead line maintenance mechanical arm.
Background
In order to ensure the safe operation of an electric power system, a plurality of overhead transmission line robots are present, and meanwhile, in order to improve the operation capacity of the robots and promote the unmanned development direction of defect detection and fault repair of the transmission lines, mechanical arms with overhaul capacity are generally required to be installed on the body structure of the overhead transmission line inspection robot, so that the development of the research on the aspect of path planning of the overhead line overhaul mechanical arms is of great significance for ensuring the risk-free operation of the overhead transmission lines.
Because the number of overhead transmission line robots with the overhauling mechanical arms is relatively small, and corresponding motion paths are preset according to specific overhead transmission line scenes in an off-line state, the overhead transmission line robots can easily collide with a transmission line, a shockproof hammer, a hydraulic wire clamp or other parts on a body structure in an operation space in the actual operation process.
At present, a path method for overhauling a mechanical arm of an overhead line mainly comprises a sampling-based method in a joint space and an inverse kinematics solution-based method in a Cartesian space, wherein a sampling planning method can well consider all joint states of the mechanical arm, but generates a large amount of useless bit shapes to increase the calculation cost, and the inverse kinematics solution-based method can quickly provide an ideal track of the tail end of the mechanical arm, but cannot ensure that all joints can meet corresponding constraints.
Therefore, how to design a path planning method for the overhead line maintenance mechanical arm, which has small calculation amount and can ensure that all joints of the mechanical arm meet corresponding constraints, becomes a problem to be solved urgently.
Disclosure of Invention
The invention provides a path planning method for an overhead line maintenance mechanical arm, which aims to solve the problems that the existing method is large in calculation amount and cannot ensure that all joints of the mechanical arm meet corresponding constraints.
The invention provides a path planning method for an overhead line maintenance mechanical arm, which comprises the following steps:
s1: acquiring obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and terminal position information of the tail end of the mechanical arm;
s2: according to the obstacle information, the operation degree threshold value, the initial position information of the tail end of the mechanical arm and the terminal position information of the tail end of the mechanical arm, planning a non-collision path of the tail end of the mechanical arm in a Cartesian space;
s3: judging whether the non-collision path planning of the tail end position of the mechanical arm is successful, if so, finishing the path planning; otherwise, performing secondary path planning.
Optionally, the planning a non-collision path of the end position of the mechanical arm in the cartesian space according to the obstacle information, the threshold of the degree of operation, the initial position information of the end of the mechanical arm, and the end position information of the end of the mechanical arm includes:
s21: planning a non-collision path from the initial position of the tail end of the mechanical arm to the end position in a Cartesian space according to the initial position information of the tail end of the mechanical arm and the end position information of the tail end of the mechanical arm to obtain a position point in the non-collision path;
s22: and performing inverse kinematics solution on all the position points to obtain inverse solution values.
Optionally, judging whether the path planning is successful, if so, ending the path planning; otherwise, the performing the secondary path planning includes:
judging whether all the inverse solution values exist and are greater than an operation degree threshold value, and finishing path planning if all the inverse solution values exist and are greater than the operation degree threshold value; otherwise, performing secondary path planning.
Optionally, the secondary path planning includes:
s31: deleting the position points without inverse solution values, and storing the deleted position points as a plurality of feasible path segments;
s32: acquiring end points of all feasible path sections, sequencing all the end points according to the direction from the initial position to the end position of the tail end of the mechanical arm, and constructing a position point sequence;
s33: constructing a plurality of sphere spaces by taking points positioned at odd number positions and points at the right end adjacent to even number positions in the position point sequence as diameter end points;
s34: randomly sampling a collision-free mechanical arm shape, performing positive kinematic solution to obtain a positive solution, judging whether the positive solution is positioned in a sphere space, if so, keeping and performing the next step, otherwise, re-sampling;
s35: acquiring a preset radius, and connecting all positive solutions in the same sphere space by taking the preset radius as a connecting range;
s36: judging whether all the points at the odd number position in the position point sequence are connected with the points at the right end adjacent to the even number position, and finishing path planning if the connection is successful; otherwise, the process goes to S34.
Alternatively, in the connecting all the positive solutions located in the same sphere space, the two connected sampling collision-free arm-shaped positive solutions are located in the same sphere space.
Optionally, the euclidean distance between two of said positive solutions is less than a predetermined radius.
The invention provides a path planning method for an overhead line maintenance mechanical arm, which comprises the following steps: acquiring obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and terminal position information of the tail end of the mechanical arm; according to the obstacle information, the operation degree threshold value, the initial position information of the tail end of the mechanical arm and the terminal position information of the tail end of the mechanical arm, planning a non-collision path of the tail end of the mechanical arm in a Cartesian space; judging whether the non-collision path planning of the tail end position of the mechanical arm is successful, if so, finishing the path planning; otherwise, performing secondary path planning. According to the method, the non-collision path planning is carried out aiming at the tail end position of the mechanical arm in the Cartesian space, a feasible path of the tail end of the mechanical arm is provided, a large number of invalid sampling points can be avoided, the calculated amount is reduced, then secondary path planning is carried out until the feasible paths are connected, and the whole path planning of the tail end of the mechanical arm is completed.
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In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without any inventive exercise.
Fig. 1 is a flowchart of a path planning method for an overhead line maintenance robot according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings in the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described, and it will be appreciated by those skilled in the art that the present invention may be embodied without departing from the spirit and scope of the invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
Referring to fig. 1, the present invention provides a path planning method for an overhead line service robot arm, the method comprising:
s1: acquiring obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and terminal position information of the tail end of the mechanical arm;
the sensing system carried by the platform where the overhead line maintenance mechanical arm is located acquires obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and end point position information of the tail end of the mechanical arm, and the sensing system is a sensing element or a camera or a video camera or a laser radar and the like, so long as space object geometric information can be provided.
S2: according to the obstacle information, the operation degree threshold value, the initial position information of the tail end of the mechanical arm and the terminal position information of the tail end of the mechanical arm, planning a non-collision path of the tail end of the mechanical arm in a Cartesian space;
s3: judging whether the non-collision path planning of the tail end position of the mechanical arm is successful, if so, finishing the path planning; otherwise, performing secondary path planning.
Optionally, the planning a non-collision path of the end position of the mechanical arm in the cartesian space according to the obstacle information, the threshold of the degree of operation, the initial position information of the end of the mechanical arm, and the end position information of the end of the mechanical arm includes:
s21: planning a non-collision path from the initial position of the tail end of the mechanical arm to the end position in a Cartesian space according to the initial position information of the tail end of the mechanical arm and the end position information of the tail end of the mechanical arm to obtain a position point in the non-collision path;
in a Cartesian space, the states of all joints of the mechanical arm do not need to be considered, and only a non-collision path from an initial position to a terminal position needs to be planned at the tail end of the mechanical arm.
S22: and performing inverse kinematics solution on all the position points to obtain inverse solution values.
Optionally, judging whether the path planning is successful, if so, ending the path planning; otherwise, the performing the secondary path planning includes:
judging whether all the inverse solution values exist and are greater than an operation degree threshold value, and finishing path planning if all the inverse solution values exist and are greater than the operation degree threshold value; otherwise, performing secondary path planning.
Optionally, the secondary path planning includes:
s31: deleting the position points without inverse solution values, and storing the deleted position points as a plurality of feasible path segments;
s32: acquiring end points of all feasible path sections, sequencing all the end points according to the direction from the initial position to the end position of the tail end of the mechanical arm, and constructing a position point sequence;
s33: constructing a plurality of sphere spaces by taking points positioned at odd number positions and points at the right end adjacent to even number positions in the position point sequence as diameter end points;
s34: randomly sampling a collision-free mechanical arm shape, performing positive kinematic solution to obtain a positive solution, judging whether the positive solution is positioned in a sphere space, if so, keeping and performing the next step, otherwise, re-sampling;
s35: acquiring a preset radius, and connecting all positive solutions in the same sphere space by taking the preset radius as a connecting range;
s36: judging whether all the points at the odd number position in the position point sequence are connected with the points at the right end adjacent to the even number position, and finishing path planning if the connection is successful; otherwise, the process goes to S34.
Aiming at the actual operation space or the simulation operation space of the overhead line maintenance mechanical arm, firstly providing obstacle information of the environment around the overhead line maintenance mechanical arm, an initial position and a terminal position of the mechanical arm end by a sensing system carried by a platform where the overhead line maintenance mechanical arm is located, and setting a preset radius; secondly, in a Cartesian space, the states of all joints of the mechanical arm are not considered, only a non-collision path from an initial position to a terminal position is planned at the tail end of the mechanical arm, and inverse kinematics solution is carried out on all position points in the path;
if the inverse solution exists and meets the requirements that the operability is not zero and the obstacle does not collide, the path planning process is completed, otherwise, the following second planning process is required:
firstly, deleting the position points without inverse solution values, and storing the deleted position points as a plurality of feasible path segments; secondly, numbering the feasible path segments (1,2, …, i, i +1, …), wherein the serial number of the feasible path segment close to the initial position is smaller than that of the feasible path segment close to the end position, and for convenience of description, the end point close to the initial position in the ith path segment is a near point of the ith feasible path segment, and the end point close to the end position is a far point of the ith feasible path segment; then, planning between a far point of the ith feasible path segment and a near point of the (i + 1) th feasible path segment, wherein due to the fact that an obstacle exists between the ith path segment and the (i + 1) th path segment, and the obstacle is caused by a mechanical arm joint instead of a tail end, planning needs to be carried out in a mechanical arm joint space, and the following steps are specifically carried out:
randomly sampling a collision-free mechanical arm configuration in a joint space, performing positive kinematics solution to obtain a corresponding mechanical arm tail end position, if the tail end position is in a sphere space between a far point of an ith feasible path section and a near point of an (i + 1) th feasible path section, reserving the mechanical arm configuration, and otherwise, sampling again; if the position of the sampled mechanical arm is reserved, connecting the sampled mechanical arm with the reserved sampling points, and in order to ensure the validity of connection, two points of requirements are required to be met, namely positive solutions of two connected sampling points are located in the same sphere space, and the Euclidean distance between the two positive solutions is smaller than a preset radius, otherwise, re-sampling and re-connection are required; according to the above process, the path planning process is completed until the end points of all the feasible path segments are connected.
Alternatively, in the connecting all the positive solutions located in the same sphere space, the two connected sampling collision-free arm-shaped positive solutions are located in the same sphere space.
Optionally, the euclidean distance between two of said positive solutions is less than a predetermined radius.
The method provided by the invention firstly plans in the operation space of the mechanical arm, can quickly provide a mechanical arm path, and can avoid generating a large number of invalid sampling points compared with the method that planning in the joint space is adopted at first; however, related constraints such as non-collision and high operability can be simply and intuitively considered in the planning in the joint space, and the problem of difficult inverse kinematics solution caused by the fact that too many constraints need to be considered in the planning in the operation space can be avoided; therefore, the method provided by the patent can reduce the calculation cost, improve the planning efficiency and ensure the real-time operation requirement of the path planning of the overhead line maintenance mechanical arm.
The invention provides a path planning method for an overhead line maintenance mechanical arm, which comprises the following steps: acquiring obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and terminal position information of the tail end of the mechanical arm; according to the obstacle information, the operation degree threshold value, the initial position information of the tail end of the mechanical arm and the terminal position information of the tail end of the mechanical arm, planning a non-collision path of the tail end of the mechanical arm in a Cartesian space; judging whether the non-collision path planning of the tail end position of the mechanical arm is successful, if so, finishing the path planning; otherwise, performing secondary path planning. According to the method, the non-collision path planning is carried out aiming at the tail end position of the mechanical arm in the Cartesian space, a feasible path of the tail end of the mechanical arm is provided, a large number of invalid sampling points can be avoided, the calculated amount is reduced, then secondary path planning is carried out until the feasible paths are connected, and the whole path planning of the tail end of the mechanical arm is completed.
The foregoing is merely a detailed description of the invention, and it should be noted that modifications and adaptations by those skilled in the art may be made without departing from the principles of the invention, and should be considered as within the scope of the invention.
Claims (3)
1. A path planning method for an overhead line maintenance mechanical arm, the method comprising:
s1: acquiring obstacle information, an operation degree threshold value, initial position information of the tail end of the mechanical arm and terminal position information of the tail end of the mechanical arm;
s2: according to the obstacle information, the operation degree threshold value, the initial position information of the tail end of the mechanical arm and the terminal position information of the tail end of the mechanical arm, planning a non-collision path of the tail end of the mechanical arm in a Cartesian space;
the non-collision path planning of the tail end position of the mechanical arm in the Cartesian space according to the obstacle information, the operation degree threshold, the initial position information of the tail end of the mechanical arm and the end position information of the tail end of the mechanical arm comprises the following steps:
s21: planning a non-collision path from the initial position of the tail end of the mechanical arm to the end position in a Cartesian space according to the initial position information of the tail end of the mechanical arm and the end position information of the tail end of the mechanical arm to obtain a position point in the non-collision path;
s22: performing inverse kinematics solution on all the position points to obtain inverse solution values;
s3: judging whether the non-collision path planning of the tail end position of the mechanical arm is successful, if so, finishing the path planning; otherwise, performing secondary path planning;
judging whether the path planning is successful or not, if so, finishing the path planning; otherwise, the performing the secondary path planning includes:
judging whether all the inverse solution values exist and are greater than an operation degree threshold value, and finishing path planning if all the inverse solution values exist and are greater than the operation degree threshold value; otherwise, performing secondary path planning;
the secondary path planning comprises:
s31: deleting the position points without inverse solution values, and storing the deleted position points as a plurality of feasible path segments;
s32: acquiring end points of all feasible path sections, sequencing all the end points according to the direction from the initial position to the end position of the tail end of the mechanical arm, and constructing a position point sequence;
s33: constructing a plurality of sphere spaces by taking points positioned at odd number positions and points at the right end adjacent to even number positions in the position point sequence as diameter end points;
s34: randomly sampling a collision-free mechanical arm shape, performing positive kinematic solution to obtain a positive solution, judging whether the positive solution is positioned in a sphere space, if so, keeping and performing the next step, otherwise, re-sampling;
s35: acquiring a preset radius, and connecting all positive solutions in the same sphere space by taking the preset radius as a connecting range;
s36: judging whether all the points at the odd number position in the position point sequence are connected with the points at the right end adjacent to the even number position, and finishing path planning if the connection is successful; otherwise, the process goes to S34.
2. A path planning method for an overhead line service robot as claimed in claim 1, wherein in connecting all positive solutions located in the same sphere space, the positive solutions of the two sampled collision-free robot arms that are connected are located in the same sphere space.
3. A path planning method for an overhead line servicing robot as claimed in claim 1, wherein the euclidean distance between the two positive solutions is less than a preset radius.
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