CN111538415B - Method and system for judging maintenance accessibility - Google Patents
Method and system for judging maintenance accessibility Download PDFInfo
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- CN111538415B CN111538415B CN202010348359.3A CN202010348359A CN111538415B CN 111538415 B CN111538415 B CN 111538415B CN 202010348359 A CN202010348359 A CN 202010348359A CN 111538415 B CN111538415 B CN 111538415B
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Abstract
The invention discloses a method and a system for judging maintenance accessibility. The method comprises the following steps: calculating all the postures of the free movement of the arms when the palm position is fixed to form an arm posture initial solution set; reconstructing a three-dimensional model of a product; carrying out intersection detection on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result; and determining the maintenance accessibility according to the detection result. The method and the system for judging the maintenance accessibility can screen all accessible postures, and break the limitation of the prior art.
Description
Technical Field
The invention relates to the technical field of maintenance, in particular to a method and a system for judging maintenance accessibility.
Background
With the development of the technology, various products are developed towards high integration, automation and intellectualization, the maintenance difficulty is increased, and in order to ensure that the products have better use reliability and lower full life cycle cost, maintainability design and analysis become indispensable researches in the whole design process.
The accessibility for maintenance is an important factor in the design and evaluation of maintainability, and the good accessibility design can enable maintenance personnel to quickly and conveniently approach a maintenance part, thereby reducing the maintenance time and improving the working efficiency.
The existing maintenance accessibility analysis is mainly based on methods such as physical prototypes, virtual prototypes and geometric analysis. However, these methods still have some drawbacks. For example, methods based on geometric analysis have limitations that can only yield a limited set of reachable solutions.
Disclosure of Invention
Therefore, there is a need to provide a method and a system for determining a reachable maintenance, which overcome the limitation of the existing analysis method.
In order to achieve the purpose, the invention provides the following scheme:
a method for judging whether maintenance can be achieved comprises the following steps:
calculating all the postures of the free movement of the arms when the palm position is fixed to form an arm posture initial solution set;
reconstructing a three-dimensional model of a product;
carrying out intersection detection on each arm form determined by the arm posture initial solution set and a product three-dimensional model to obtain a detection result;
and determining the maintenance accessibility according to the detection result.
Optionally, calculating all postures of the arm in free movement when the palm position is fixed, forming an arm posture initial solution set, specifically including:
representing the front arm and the rear arm as connecting rods, establishing an arm model by taking a wrist joint coordinate system as a reference coordinate system and taking the palm position as a condition;
the positions of all joints are formed by setting the degrees of freedom of a wrist joint, an elbow joint and a shoulder joint;
connecting and fitting each elbow joint position and each wrist joint position into a cylinder with a radius of a first length to form all forearm postures, and connecting and fitting each elbow joint position and each shoulder joint position into a cylinder with a radius of a second length to form all hind arm postures;
and screening all the forearm postures and all the arm postures which can be formed by the rear arm postures by utilizing permutation and combination to obtain the initial solution set of the arm postures.
Optionally, the reconstructing a three-dimensional model of a product specifically includes:
on the basis of an original product model, taking the first length as an expansion thickness, and expanding all surfaces of the original product model outwards to obtain a forearm intersection detection model;
on the basis of the original product model, with the second length as an expansion thickness, expanding all surfaces of the original product model outwards to obtain a rear arm intersection detection model;
dividing the forearm intersection detection model and the rear arm intersection detection model into a plurality of regular patterns;
and simplifying the cylinders of the front arm postures and the cylinders of the rear arm postures into axis line segments of the cylinders to obtain a plurality of front arm line segments and a plurality of rear arm line segments.
Optionally, the intersecting detection is performed on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result, and the method specifically includes:
judging whether each forearm line segment intersects with a plurality of divided regular graphs of the forearm intersection detection model to obtain a first judgment result;
if the first judgment result is yes, marking the forearm line segment with the first judgment result of yes as an unreachable forearm line segment;
if the first judgment result is negative, marking the forearm line segment with the negative first judgment result as a reachable forearm line segment;
judging whether each rear arm line segment corresponding to each reachable front arm line segment is intersected with a plurality of divided regular graphs of the rear arm intersection detection model or not to obtain a second judgment result;
if the second judgment result is yes, marking the rear arm line segment with the second judgment result of yes as an unreachable rear arm line segment;
if the second judgment result is negative, marking the rear arm line segment with the negative second judgment result as a reachable rear arm line segment;
and determining the attitude formed by the reachable rear arm line segment and the reachable front arm line segment corresponding to the reachable rear arm line segment as the maintenance reachable attitude.
Optionally, the determining the maintenance accessibility according to the detection result specifically includes:
and calculating the percentage of the number of the maintenance reachable postures to the number of the arm postures in the initial solution set of the arm postures to obtain the maintenance reachable degree.
The invention also discloses a maintenance reachable judgment system, which comprises:
the arm posture determining module is used for calculating all the postures of the free movement of the arm when the palm position is fixed to form an arm posture initial solution set;
the product model reconstruction module is used for reconstructing a three-dimensional model of a product;
the intersection detection module is used for carrying out intersection detection on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result;
and the maintenance accessibility determining module is used for determining the maintenance accessibility according to the detection result.
Optionally, the arm posture determining module includes:
the arm model establishing unit is used for representing the front arm and the rear arm as connecting rods, establishing an arm model by taking a wrist joint coordinate system as a reference coordinate system and taking the palm position as a fixed condition;
the joint position calculation unit is used for forming the positions of all joints by setting the degrees of freedom of the wrist joint, the elbow joint and the shoulder joint;
the cylinder front and rear arm construction unit is used for connecting and fitting each elbow joint position and each wrist joint position into a cylinder with a first length as a radius to form all forearm postures, and connecting and fitting each elbow joint position and each shoulder joint position into a cylinder with a second length as a radius to form all rear arm postures;
and the arm posture forming unit is used for screening all the forearm postures and all the arm postures which can be formed by the rear arm postures by utilizing permutation and combination to obtain the initial solution set of the arm postures.
Optionally, the product model reconstruction module includes:
the first expansion unit is used for expanding all surfaces of the original product model outwards by taking the first length as an expansion thickness on the basis of the original product model to obtain a forearm intersection detection model;
the second expansion unit is used for expanding all the surfaces of the original product model outwards by taking the second length as an expansion thickness on the basis of the original product model to obtain a rear arm intersection detection model;
a regular pattern division unit configured to divide the front arm intersection detection model and the rear arm intersection detection model into a plurality of regular patterns;
and the front-rear arm simplifying unit is used for simplifying the cylinders of the front arm postures and the cylinders of the rear arm postures into axis line segments of the cylinders to obtain a plurality of front arm line segments and a plurality of rear arm line segments.
Optionally, the intersection detecting module includes:
the first judgment unit is used for judging whether each forearm line segment intersects with a plurality of divided regular graphs of the forearm intersection detection model to obtain a first judgment result;
an unreachable forearm line segment marking unit, configured to mark, if the first determination result is yes, a forearm line segment whose first determination result is yes as an unreachable forearm line segment;
a reachable forearm line segment marking unit, configured to mark, if the first determination result is negative, a forearm line segment for which the first determination result is negative as a reachable forearm line segment;
the second judgment unit is used for judging whether each rear arm line segment corresponding to each reachable front arm line segment is intersected with a plurality of divided regular graphs of the rear arm intersection detection model or not to obtain a second judgment result;
an unreachable rear arm line segment marking unit, configured to mark, if the second determination result is yes, the rear arm line segment whose second determination result is yes as an unreachable rear arm line segment;
a reachable rear arm line segment marking unit, configured to mark, if the second determination result is negative, a rear arm line segment for which the second determination result is negative as a reachable rear arm line segment;
and the maintenance reachable posture screening unit is used for determining the posture formed by the reachable rear arm line segment and the reachable front arm line segment corresponding to the reachable rear arm line segment as the maintenance reachable posture.
Optionally, the maintenance accessibility determining module includes:
and the proportion calculation unit is used for calculating the percentage of the number of the maintenance reachable postures to the number of the arm postures in the initial solution set of the arm postures to obtain the maintenance reachability.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a maintenance reachable judgment method and a maintenance reachable judgment system. The invention screens the reachable postures from all the postures of the free movement of the arm, thereby being capable of screening all the reachable postures and breaking the limitation of the prior art.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
FIG. 1 is a flowchart of a method for determining whether a repair is available in embodiment 1 of the present invention;
FIG. 2 is a schematic view of a coordinate system of a human arm;
FIG. 3 is a diagram of an original scene for intersection detection;
FIG. 4 is a schematic diagram of an initial solution set of arm poses;
fig. 5 is a schematic diagram of an intersection detection scenario 1 in embodiment 2;
fig. 6 is a schematic diagram of an intersection detection scenario 2 in embodiment 2;
fig. 7 is a system configuration diagram of a repair-reachable determination system according to embodiment 3.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of 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 order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
The invention provides a method and a system for judging whether maintenance can be achieved. Whether the maintenance part can be touched when the maintenance can be achieved or not is a primary condition for maintaining the product, so that whether the product can be maintained or not needs to be judged. The invention starts from a global arm posture initial solution set, mainly considers the spatial position of an arm joint point and the constraint of the degree of freedom of the arm joint, realizes the quantitative analysis and characterization of the maintenance accessibility through the generation, optimization and screening of the arm posture initial solution set, can reduce the influence of human subjective factors on the maintenance accessibility analysis, realizes the automatic judgment of the maintenance accessibility, and breaks through the limitation of the existing maintenance accessibility analysis.
The basic principle of the invention is as follows: when the palm is fixed, all postures of the arm which can freely move are solved, the space position of the joint point and the constraint of the freedom degree of the arm joint are considered, a maintenance scene three-dimensional model is constructed, all postures of the arm are intersected with products in the three-dimensional scene, and whether a reachable solution exists is judged.
The specific embodiment of the invention is as follows:
example 1:
fig. 1 is a flowchart of a method for determining whether a repair is available in embodiment 1 of the present invention.
Referring to fig. 1, the method for determining the availability of the maintenance includes:
step 101: and calculating all the postures of the free movement of the arms when the palm positions are fixed to form an arm posture initial solution set.
This step 101 includes two processes, model creation and solution of the initial solution set of arm poses.
The essence of the model creation process is to solve the position expression of each joint of the arm in the global space when the palm position is fixed: establishing a model reflecting the motion of the human arm in space, determining a reference coordinate system of arm joint posture data, obtaining an expression form of each joint space position under the reference coordinate system, and representing the arm space posture.
The model creating process comprises the following steps: and representing the front arm and the rear arm as connecting rods, taking a wrist joint coordinate system as a reference coordinate system, and establishing an arm model under the condition that the palm position is fixed.
One specific embodiment of the model creation process is as follows:
and establishing a connecting rod model to represent the arm. Establishing a coordinate system at the end of each rod member, as shown in FIG. 2, wherein l is the length of the forearm, h is the length of the hind arm, the three nodes from bottom to top are the wrist joint, elbow joint and shoulder joint, and 0 (x) coordinate system0-y0-z0) Is a base coordinate system, 1-7 coordinate system (x)1-y1-z1、x2-y2-z2、…、x7-y7-z7) The coordinate system is respectively established at a first degree of freedom (namely the left-right swing angle of the wrist joint), a forearm rotating degree of freedom around an axis, a second degree of freedom (namely the up-down swing angle of the wrist joint), an elbow joint degree of freedom and a first degree, a second degree and a third degree of freedom (namely the up-down, left-right and front-back swing angles of the shoulder joint).
Two adjacent coordinate systems are then linked by a homogeneous coordinate transformation matrix. The coordinate transformation matrix from the i coordinate system to the i-1 coordinate system is:
in the formula: r3*3Is a rotation matrix;
P3*1is a position matrix;
O1*3is a perspective matrix;
I1*1is a proportional matrix;
aiindicating the vertical distance (e.g. a) between two adjacent joint axes (z-axis)1I.e. z1And z0The vertical distance therebetween);
αirepresenting the angle (e.g. alpha) between two adjacent joint axes (z-axis)1I.e. z1And z0The included angle therebetween);
dithe distance (e.g. d) between perpendicular lines (x-axis) representing the axes of two adjacent joints1I.e. x1And x0The distance therebetween);
θithe angle (e.g. theta) between perpendicular lines (x-axis) representing the axes of two adjacent joints1I.e. x1And x0The angle therebetween).
And transforming the elbow joint and shoulder joint coordinates to a wrist joint coordinate system through a plurality of homogeneous coordinate transformation matrixes to obtain a position expression of the elbow joint and the shoulder joint and represent the arm space posture. The variable in the position expression is the angle theta of each joint degree of freedom1～θ4Wherein the elbow joint position expression is:
the position expression of the shoulder joint is
Wherein l is the length of the front arm, h is the length of the rear arm, s represents sin, c represents cos, 1-4 represents theta1～θ4The first degree of freedom (namely the left-right swing angle of the wrist joint), the rotation degree of freedom of the forearm around the axis, the second degree of freedom (namely the up-down swing angle of the wrist joint) and the elbow joint degree of freedom are respectively provided. Values of l and h and θ1～θ4The value range of (a) can be set according to different people.
The principle of the solution process of the initial solution set of the arm postures is as follows:
determining an angle as joint change graduation, and obtaining an initial solution set containing a plurality of groups of arm postures under the constraint of a change range on a joint position expression in the model establishing process, wherein the initial solution set can be used as the generation of the initial solution set when the palm is fixed and the arm can freely move. And selecting a proper joint change angle to generate an initial solution space with a proper scale, namely optimizing the initial solution space.
The solving process of the arm posture initial solution set is as follows:
the positions of all joints are formed by setting the degrees of freedom of a wrist joint, an elbow joint and a shoulder joint; connecting and fitting each elbow joint position and each wrist joint position into a cylinder with a radius of a first length to form all forearm postures, and connecting and fitting each elbow joint position and each shoulder joint position into a cylinder with a radius of a second length to form all hind arm postures; and screening all the forearm postures and all the arm postures which can be formed by the rear arm postures by utilizing permutation and combination to obtain the initial solution set of the arm postures.
One specific implementation of the solution process for the initial solution set of arm poses is as follows:
according to the position expression form of each joint under the wrist joint coordinate system in the model establishing process, different postures of the human arm, namely the positions of each joint, can be obtained by setting the degree of freedom angle of each joint.
In the expression of the positions of the elbow joint and the shoulder joint in the model establishing process, the angle change graduation of the joint is set to be n degrees, 4 angles are respectively taken once every n degrees from the value lower limit, and 4 sets containing a plurality of angle values are obtained, wherein the 4 sets are values of 4 degrees of freedom.
And then values are taken from the 4 sets respectively to obtain a set containing 4 angle values. And traversing all the possible values to obtain different value sets. And substituting the value sets into the elbow joint and shoulder joint position expressions respectively to obtain the elbow joint and shoulder joint positions corresponding to the value sets. Connecting all the wrist joint positions and all the elbow joint positions into a cylinder to represent the forearm, and connecting all the elbow joint positions and all the shoulder joint positions into another cylinder to represent the hind arm, namely representing the posture of the arm of the human body. In this way, the original continuous initial solution space of the arm postures can be discretized, and the discretized solutions can be expressed as all postures of the human arm which can freely move in the barrier-free space when the palm is fixed.
Step 102: and reconstructing a three-dimensional model of the product.
The principle of this step 102 is: constructing a virtual environment supporting computational analysis, and reconstructing a three-dimensional model of a product according to the original three-dimensional model of the product and computational requirements so as to simplify the process and improve the efficiency; and then representing the model in a parameter form according to the self characteristics of the reconstructed model.
Step 102 specifically includes:
on the basis of an original product model, taking the first length as an expansion thickness, and expanding all surfaces of the original product model outwards to obtain a forearm intersection detection model;
on the basis of the original product model, with the second length as an expansion thickness, expanding all surfaces of the original product model outwards to obtain a rear arm intersection detection model;
dividing the forearm intersection detection model and the rear arm intersection detection model into a plurality of regular patterns;
and simplifying the cylinders of the front arm postures and the cylinders of the rear arm postures into axis line segments of the cylinders to obtain a plurality of front arm line segments and a plurality of rear arm line segments.
One embodiment of step 102 is as follows:
in order to simplify the judgment of the spatial relationship in the subsequent steps, the front arm and the rear arm which are originally regarded as cylinders in the step 101 are respectively processed into line segments (represented by central axes of the corresponding cylinders respectively), the radius of the cylinders is superposed on the three-dimensional models of the products, so that the surfaces of the three-dimensional models of the products are expanded outwards by the same thickness, and the product models are reconstructed. Because the judgment of the relationship between the arm and the space needs to consider the forearm and the rear arm at the same time, and the thicknesses of the forearm and the rear arm are different, two scenes for calculation need to be constructed: the thickness of the front arm and the thickness of the rear arm are respectively recorded as r1 (first length) and r2 (second length), and the surfaces are expanded outwards by the thickness of r1 to obtain a scene 1 (front arm intersection detection model) for intersection detection with the front arm; the surfaces are expanded outward by r2 thickness to obtain scene 2 (posterior arm intersection detection model) for intersection detection with the posterior arm.
After the three-dimensional model of the product is reconstructed, if the model is regular, the three-dimensional model is represented by a bounding sphere, a bounding box, a cylinder, a capsule body and the like; if the model is irregular, the model is subjected to meshing and represented by a triangular patch. Geometric feature data of each product is then obtained.
Wherein, each type of product data is shown in table 1:
TABLE 1 product geometry characteristic data type Table
Step 103: and carrying out intersection detection on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result.
Step 103 comprises:
judging whether each forearm line segment intersects with a plurality of divided regular graphs of the forearm intersection detection model to obtain a first judgment result;
if the first judgment result is yes, marking the forearm line segment with the first judgment result of yes as an unreachable forearm line segment;
if the first judgment result is negative, marking the forearm line segment with the negative first judgment result as a reachable forearm line segment;
judging whether each rear arm line segment corresponding to each reachable front arm line segment is intersected with a plurality of divided regular graphs of the rear arm intersection detection model or not to obtain a second judgment result;
if the second judgment result is yes, marking the rear arm line segment with the second judgment result of yes as an unreachable rear arm line segment;
if the second judgment result is negative, marking the rear arm line segment with the negative second judgment result as a reachable rear arm line segment;
and determining the attitude formed by the reachable rear arm line segment and the reachable front arm line segment corresponding to the reachable rear arm line segment as the maintenance reachable attitude.
One embodiment of step 103 is as follows:
intersection detection is performed on the forearm and the model of the scene 1 in step 102, and the spatial relationship between the forearm line segment and the model represented by a regular graph such as a bounding sphere is determined.
Wherein:
when the forearm line segment and the enclosing ball O are judged, the distance d from the center of the ball to the forearm line segment is solved and is compared with the radius R of the enclosing ball O, if d is larger than R, the forearm line segment does not intersect with the enclosing ball O, and if d is not larger than R, the forearm line segment intersects with the ball O;
when the forearm line segment and the cylinder C are judged, respectively solving the intersection points of a straight line where the forearm line segment is located, a plane where the upper bottom surface of the cylinder C is located, a plane where the lower bottom surface of the cylinder C is located and a curved surface where the side surface of the cylinder C is located, if the intersection points are located in the forearm line segment, the upper bottom surface of the cylinder C, the lower bottom surface of the cylinder C or the side surface of the cylinder C, the forearm line segment is intersected with the cylinder C, and;
when the forearm line segment and the capsule body D are judged, solving the shortest distance D between the forearm line segment and the axis of the capsule body, comparing the shortest distance D with the radius R of the capsule body D, if D is larger than R, the line segment is not intersected with the capsule body D, and if D is not larger than R, the line segment is intersected with the capsule body D;
when the forearm line segment and the bounding box E are judged, 6 axes, namely 3 surface normals of the bounding box E and a cross product vector of the 3 surface normals and the forearm line segment direction vector, are selected for judgment, and as long as one axis is a separation axis, namely the axis is used as a hyperplane, the forearm line segment and the bounding box E can be respectively positioned at two sides of the hyperplane, the forearm line segment and the bounding box E are not intersected, otherwise, the forearm line segment and the bounding box E are intersected;
and when the forearm line segment and the triangular patch F are judged, solving the intersection point of the straight line of the forearm line segment and the plane of the triangular patch F, if the intersection point is not in the forearm line segment but in the triangular patch F, intersecting the forearm line segment and the triangular patch F, and otherwise, not intersecting.
When the spatial relation is judged, the surrounding ball, the cylinder, the capsule body, the surrounding box and the triangular patch are sequentially judged, if the intersection point exists, the posture cannot be reached, and the corresponding rear arm line segment does not need to be detected.
And judging the spatial relationship between the rear arm line segments corresponding to the non-intersected front arm line segments and the model of the scene 2 in the same intersection detection sequence, wherein the logic is the same. If the rear arm line segments do not intersect, the group of arm postures is the reachable posture. If there is no gesture that meets the condition, the position is not reachable.
Step 104: and determining the maintenance accessibility according to the detection result.
The step 104 specifically includes:
and calculating the percentage of the number of the maintenance reachable postures to the number of the arm postures in the initial solution set of the arm postures to obtain the maintenance reachable degree. This step may allow for a quantification of achievable maintenance.
Example 2:
this example 2 is a specific example of example 1.
The method for determining the accessibility of the maintenance according to the present invention will be specifically described with reference to fig. 3.
Model creation process of step 101:
1) establishing a multi-link mechanism, and characterizing the arm, as shown in the attached figure 2;
2) connecting adjacent coordinate systems through a D-H matrix, wherein the D-H matrix is as follows:
3) converting the elbow joint and the shoulder joint into a wrist joint coordinate system respectively through a plurality of times of conversion;
4) obtaining the coordinate expressions of the elbow joint and the shoulder joint, wherein the coordinate expressions are respectively as follows:
the solution process of the initial solution set of the arm postures in the step 101:
1) determining the respective angle change ranges of the arm length and the joint, wherein the length l of the front arm is 267mm, the length h of the rear arm is 339mm, and the angle ranges in the coordinate expression are respectively as follows: theta is less than or equal to minus 45 degrees1≤45°，0°≤θ2≤160°，-85°≤θ3≤100°，0°≤θ4≤142°；
2) Setting the angle change graduation of the freedom degrees of each joint to be 10 degrees to obtain each angle set;
3) obtaining coordinate points of the wrist joint, the elbow joint and the shoulder joint under different angle combinations, as shown in figure 4, wherein the origin is the wrist joint, and the inner layer and the outer layer respectively represent the elbow joint and the shoulder joint;
4) in fig. 4, the wrist joint and the elbow joint, and the elbow joint and the corresponding shoulder joint are connected into segments to form two cylinders, which can represent the forearm and the hind arm.
Step 102:
1) fig. 3 is an original scene of intersection detection, which includes 3 cuboids, 1 sphere, 1 cylinder, and 1 line segment. The line segments represent the palm position and the other shapes represent the products in the scene.
2) And (3) respectively expanding the shape surfaces in the scene by 30mm outwards to form a scene 1 and expanding the shape surfaces in the scene by 50mm outwards to form a scene 2. Wherein, the scene 1 is the scene used for the intersection detection calculation with the forearm as shown in fig. 5; scene 2 is the scene used in the intersection detection calculation with the trailing arm, as shown in fig. 6.
3) In scenes 1 and 2, the ball is represented by the center position and radius; a cuboid (bounding box) is represented by a central coordinate, a range vector (half of the length of three sides) and a local coordinate axis (vector of three sides); the cylinder is represented by axis endpoint coordinates, radius. The geometric features of the objects in scene 1 and scene 2 are shown in tables 2 and 3, respectively:
table 2 table of geometric characteristics of objects in scene 1
Table 3 table of geometric characteristics of objects in scene 2
Step 103:
1) and (4) detecting the intersection of the forearm processed into the line segment in the step 102 and the product in the scene 1, and detecting the forearm, the cylinder and the cuboid in sequence. If the front arm has an intersection point with the ball, the cylinder and the cuboid, the posture of the group can not be reached, and the corresponding rear arm does not need to be detected.
2) And (3) detecting the intersection of the rear arm posture corresponding to the front arm posture which is not intersected with the product and the product in the scene 2, and detecting in the order of a ball, a cylinder and a cuboid in the same way, wherein the logic is the same as that of 1).
3) If scene 2 is not intersected in the rear arm poses, the set of poses is an reachable pose.
Step 104:
the initial solution set in step 101 contains 48450 free poses of human arms freely movable in an unobstructed space. In step 103, the reachable postures are determined to be 31898 groups, that is, 31898 groups of postures in step 103 are the postures reachable by maintenance, and the maintenance accessibility can be characterized by the ratio 31898/48450, that is, 0.658369.
Example 3:
this embodiment 3 provides a maintenance reachable determination system.
Fig. 7 is a system configuration diagram of a repair-reachable determination system according to embodiment 3.
Referring to fig. 7, the service availability determination system includes:
the arm posture determining module 301 is configured to calculate all postures of the arm moving freely when the palm position is fixed, and form an arm posture initial solution set;
a product model reconstruction module 302 for reconstructing a three-dimensional model of a product;
the intersection detection module 303 is configured to perform intersection detection on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result;
and a maintenance accessibility determining module 304, configured to determine a maintenance accessibility according to the detection result.
Optionally, the arm posture determining module 301 includes:
the arm model establishing unit is used for representing the front arm and the rear arm as connecting rods, establishing an arm model by taking a wrist joint coordinate system as a reference coordinate system and taking the palm position as a fixed condition;
the joint position calculation unit is used for forming the positions of all joints by setting the degrees of freedom of the wrist joint, the elbow joint and the shoulder joint;
the cylinder front and rear arm construction unit is used for connecting and fitting each elbow joint position and each wrist joint position into a cylinder with a first length as a radius to form all forearm postures, and connecting and fitting each elbow joint position and each shoulder joint position into a cylinder with a second length as a radius to form all rear arm postures;
and the arm posture forming unit is used for screening all the forearm postures and all the arm postures which can be formed by the rear arm postures by utilizing permutation and combination to obtain the initial solution set of the arm postures.
Optionally, the product model reconstruction module 302 includes:
the first expansion unit is used for expanding all surfaces of the original product model outwards by taking the first length as an expansion thickness on the basis of the original product model to obtain a forearm intersection detection model;
the second expansion unit is used for expanding all the surfaces of the original product model outwards by taking the second length as an expansion thickness on the basis of the original product model to obtain a rear arm intersection detection model;
a regular pattern division unit configured to divide the front arm intersection detection model and the rear arm intersection detection model into a plurality of regular patterns;
and the front-rear arm simplifying unit is used for simplifying the cylinders of the front arm postures and the cylinders of the rear arm postures into axis line segments of the cylinders to obtain a plurality of front arm line segments and a plurality of rear arm line segments.
Optionally, the intersection detecting module 303 includes:
the first judgment unit is used for judging whether each forearm line segment intersects with a plurality of divided regular graphs of the forearm intersection detection model to obtain a first judgment result;
an unreachable forearm line segment marking unit, configured to mark, if the first determination result is yes, a forearm line segment whose first determination result is yes as an unreachable forearm line segment;
a reachable forearm line segment marking unit, configured to mark, if the first determination result is negative, a forearm line segment for which the first determination result is negative as a reachable forearm line segment;
the second judgment unit is used for judging whether each rear arm line segment corresponding to each reachable front arm line segment is intersected with a plurality of divided regular graphs of the rear arm intersection detection model or not to obtain a second judgment result;
an unreachable rear arm line segment marking unit, configured to mark, if the second determination result is yes, the rear arm line segment whose second determination result is yes as an unreachable rear arm line segment;
a reachable rear arm line segment marking unit, configured to mark, if the second determination result is negative, a rear arm line segment for which the second determination result is negative as a reachable rear arm line segment;
and the maintenance reachable posture screening unit is used for determining the posture formed by the reachable rear arm line segment and the reachable front arm line segment corresponding to the reachable rear arm line segment as the maintenance reachable posture.
Optionally, the maintenance accessibility determining module 304 includes:
and the proportion calculation unit is used for calculating the percentage of the number of the maintenance reachable postures to the number of the arm postures in the initial solution set of the arm postures to obtain the maintenance reachability.
The technical scheme of the invention has the following technical effects:
a) the judgment method for the reachable maintenance has high automation degree, almost does not need human participation and is more objective;
b) the judgment method for the accessibility of the maintenance can obtain all the accessible postures of the arm from the whole situation.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.
Claims (4)
1. A method for judging whether maintenance can be achieved is characterized by comprising the following steps:
calculating all the postures of the free movement of the arms when the palm position is fixed to form an arm posture initial solution set;
reconstructing a three-dimensional model of a product;
carrying out intersection detection on each arm form determined by the arm posture initial solution set and a product three-dimensional model to obtain a detection result;
determining the maintenance accessibility according to the detection result;
calculating all postures of the arm in free movement when the palm position is fixed, and forming an arm posture initial solution set, wherein the method specifically comprises the following steps:
representing the front arm and the rear arm as connecting rods, establishing an arm model by taking a wrist joint coordinate system as a reference coordinate system and taking the palm position as a condition;
the positions of all joints are formed by setting the degrees of freedom of a wrist joint, an elbow joint and a shoulder joint;
connecting and fitting each elbow joint position and each wrist joint position into a cylinder with a radius of a first length to form all forearm postures, and connecting and fitting each elbow joint position and each shoulder joint position into a cylinder with a radius of a second length to form all hind arm postures;
screening all the arm postures which can be formed by all the front arm postures and all the rear arm postures by utilizing permutation and combination to obtain an initial solution set of the arm postures;
the three-dimensional model of the reconstructed product specifically comprises:
on the basis of an original product model, taking the first length as an expansion thickness, and expanding all surfaces of the original product model outwards to obtain a forearm intersection detection model;
on the basis of the original product model, with the second length as an expansion thickness, expanding all surfaces of the original product model outwards to obtain a rear arm intersection detection model;
dividing the forearm intersection detection model and the rear arm intersection detection model into a plurality of regular patterns;
simplifying the cylinders of the front arm postures and the cylinders of the rear arm postures into axis line segments of the cylinders to obtain a plurality of front arm line segments and a plurality of rear arm line segments;
the intersection detection is carried out on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result, and the method specifically comprises the following steps:
judging whether each forearm line segment intersects with a plurality of divided regular graphs of the forearm intersection detection model to obtain a first judgment result;
if the first judgment result is yes, marking the forearm line segment with the first judgment result of yes as an unreachable forearm line segment;
if the first judgment result is negative, marking the forearm line segment with the negative first judgment result as a reachable forearm line segment;
judging whether each rear arm line segment corresponding to each reachable front arm line segment is intersected with a plurality of divided regular graphs of the rear arm intersection detection model or not to obtain a second judgment result;
if the second judgment result is yes, marking the rear arm line segment with the second judgment result of yes as an unreachable rear arm line segment;
if the second judgment result is negative, marking the rear arm line segment with the negative second judgment result as a reachable rear arm line segment;
and determining the attitude formed by the reachable rear arm line segment and the reachable front arm line segment corresponding to the reachable rear arm line segment as the maintenance reachable attitude.
2. The method according to claim 1, wherein the determining the maintenance accessibility according to the detection result specifically includes:
and calculating the percentage of the number of the maintenance reachable postures to the number of the arm postures in the initial solution set of the arm postures to obtain the maintenance reachable degree.
3. A repair-reachable determination system, comprising:
the arm posture determining module is used for calculating all the postures of the free movement of the arm when the palm position is fixed to form an arm posture initial solution set;
the product model reconstruction module is used for reconstructing a three-dimensional model of a product;
the intersection detection module is used for carrying out intersection detection on each arm form determined by the arm posture initial solution set and the product three-dimensional model to obtain a detection result;
the maintenance accessibility determining module is used for determining the maintenance accessibility according to the detection result;
the arm pose determination module comprises:
the arm model establishing unit is used for representing the front arm and the rear arm as connecting rods, establishing an arm model by taking a wrist joint coordinate system as a reference coordinate system and taking the palm position as a fixed condition;
the joint position calculation unit is used for forming the positions of all joints by setting the degrees of freedom of the wrist joint, the elbow joint and the shoulder joint;
the cylinder front and rear arm construction unit is used for connecting and fitting each elbow joint position and each wrist joint position into a cylinder with a first length as a radius to form all forearm postures, and connecting and fitting each elbow joint position and each shoulder joint position into a cylinder with a second length as a radius to form all rear arm postures;
the arm posture forming unit is used for screening all the arm postures which can be formed by all the forearm postures and all the rear arm postures by utilizing permutation and combination to obtain an initial solution set of the arm postures;
the product model reconstruction module comprises:
the first expansion unit is used for expanding all surfaces of the original product model outwards by taking the first length as an expansion thickness on the basis of the original product model to obtain a forearm intersection detection model;
the second expansion unit is used for expanding all the surfaces of the original product model outwards by taking the second length as an expansion thickness on the basis of the original product model to obtain a rear arm intersection detection model;
a regular pattern division unit configured to divide the front arm intersection detection model and the rear arm intersection detection model into a plurality of regular patterns;
the front and rear arm simplifying unit is used for simplifying the cylinders of the front arm postures and the cylinders of the rear arm postures into axis line segments of the cylinders to obtain a plurality of front arm line segments and a plurality of rear arm line segments;
the intersection detection module includes:
the first judgment unit is used for judging whether each forearm line segment intersects with a plurality of divided regular graphs of the forearm intersection detection model to obtain a first judgment result;
an unreachable forearm line segment marking unit, configured to mark, if the first determination result is yes, a forearm line segment whose first determination result is yes as an unreachable forearm line segment;
a reachable forearm line segment marking unit, configured to mark, if the first determination result is negative, a forearm line segment for which the first determination result is negative as a reachable forearm line segment;
the second judgment unit is used for judging whether each rear arm line segment corresponding to each reachable front arm line segment is intersected with a plurality of divided regular graphs of the rear arm intersection detection model or not to obtain a second judgment result;
an unreachable rear arm line segment marking unit, configured to mark, if the second determination result is yes, the rear arm line segment whose second determination result is yes as an unreachable rear arm line segment;
a reachable rear arm line segment marking unit, configured to mark, if the second determination result is negative, a rear arm line segment for which the second determination result is negative as a reachable rear arm line segment;
and the maintenance reachable posture screening unit is used for determining the posture formed by the reachable rear arm line segment and the reachable front arm line segment corresponding to the reachable rear arm line segment as the maintenance reachable posture.
4. The system of claim 3, wherein the repair reachability determination module comprises:
and the proportion calculation unit is used for calculating the percentage of the number of the maintenance reachable postures to the number of the arm postures in the initial solution set of the arm postures to obtain the maintenance reachability.
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