Patent Application
20180143608
Embodiments of the present disclosure generally relates to computer numerical control (CNC) machining, and in particular relate to a numerical control machining path planning method, and numerical control machining system and method.
During a CNC machining process, the CNC system machines base on a machining program input by users. A speed will be specified as a target speed by the user in the machining program, but in general, speeds of endpoints of various machining sections are not specified. If one measure may not be taken to calculate the speeds of the endpoints, in general, a speed control strategy at the endpoints is to be machined with a speed specified by the system, or the speed is reduced to be zero at the endpoint of each section. For one corner (e.g. between a line and an arc) on a machining path, in a case where a large speed is maintained, it may fail to be transited to a next section within an allowed acceleration range for a lathe since a normal acceleration at the corner increases as the speed increases. Thus, an adverse impact will occur such as shock. If next section starts to be machined after the speed is reduced to be zero at the endpoint of the previous section, the machining quality can be ensured. However, it is not effective-cost, and when the speed is increased and then reduced frequently, the surface of a machining component will be not smooth. Even sympathetic vibration will occur, which has a server-adverse impact on the machining quality.
Thus, an arc-transition function is needed during the machining process to achieve a smooth transition between machining sections and reduce the impact on the lathe. In this way, machining efficiency and machining quality can be improved.
A numerical control machining path planning method and a numerical control machining system and method are provided for the main technical problem in present disclosure, in which arc transition can be performed between machining sections such that machining efficiency is increased, impacts on the lathe is also avoided, and machining quality is improved.
In accordance with a first aspect of the present application, a numerical control machining path planning method is provided, and the method comprising: acquiring data of a first track segment AB and a second track segment BC that are adjacent before planning, wherein the first track segment AB and the second track segment BC are intersected to form a corner; determining a position relationship between the first track segment AB and the second track segment BC according to the acquired data; calculating a distance L between circle centers based on the position relationship, a radius R2 of a transitional arc EF and a radius R of at least one of the first track segment AB and the second track segment BC; calculating a coordinate (xO2, yO2) of a circle center O2 of the transitional arc EF with the distance L and a coordinate of a circle center O of the at least one of the first track segment AB and the second track segment BC; calculating coordinates (xE, yE) and (xF, yF) of end-points E and F with the radius R2 and the coordinate of the circle center O2, thereby deriving data of a track segment of the transitional arc EF; and planning the corner as data for numerical control machining path by combining the data of the track segment of the transitional arc EF and the data of the first track segment AB and the second track segment BC.
In accordance with a second aspect of the present application, a numerical control machining system is provided, and the system includes a memory, a machining control module, a machining execution module, an interpolation section determination module and an arc transition module. The memory is configured to previously store a plurality of sets of numerical control machining data, wherein each set of numerical control machining data is configured to indicate a size of a component needed to be machined. The machining control module is configured to acquire numerical control machining data of the component from the memory, and generate a numerical control machining command according to the numerical control machining data. The machining execution module is configured to drive a lathe to execute a machining operation on the component in response to the numerical control machining command. The interpolation section determination module is configured to determine whether currently-executed program section data and un-executed program section data among the numerical control machining data are interpolation section data, and generate a first result to control the machining control module to obtain one program section data. The arc transition module, configured to add track data of an arc according to the first result and a second result whether a machining type described by currently-executed program section data is one of preset arc transitional types. The machining control module further configured to generate a control command according to the added track data of the arc to control the machining execution module to drive the lathe to perform corresponding machining operation on a transition section.
In accordance with a second aspect of the present application, a numerical control machining method is provided and the method includes: determining whether currently-executed program section data and un-executed program section data are interpolation section data, and generate a first result to control to obtain one program section data; add track data of an arc according to the first result and a second result whether a machining type described by currently-executed program section data is one of preset arc transitional types; and generate a control command according to the added track data of the arc to drive a lathe to perform corresponding machining operation on a transition section.
The subsequent advantages of the present disclosure may be achieved: different from the art, Whether the arc transition module is enabled is controlled by system parameters and machining commands, and arc transition data is added according to the arc transition type of the current section data and the lathe is controlled to perform machining on the transition arc when the arc transition module is enabled, increasing flexibility and improving machining efficiency.
In order to describe the technical solution, features, achieved objectives and effect, now the present disclosure will be described more clearly and completely with reference to the accompanying drawings.
As is shown in
The memory 14 is configured to previously store more than one sets of numerical control machining data. Each set of numerical control machining data is used for describing a size of one machining component.
When the CNC machining system 10 performs numerical control machining on one component after being initialized, the machining control module 13 obtains numerical control machining data needed for machining components from the memory 14, and then analyzes the numerical control machining data to generate numerical control machining commands, where the numerical control machining commands includes commands for controlling the lathe to start and stop working, a command for starting and stopping of a main shaft, a command for rotation direction and rotation speed conversion, a command for direction, speed and manner of feed movement, a command for cutter selection, a command for length and radius compensation, a command for cutter replacement, and a command for opening and closing of cooling liquid, etc.
The machining execution module 15 drive the lathe to perform a corresponding machining operation in response to one numerical control machining command generated by the machining control module 13.
Further, each set of numerical control machining data includes a plurality of program sections. Each program section may be a continuous string used as one unit to be processed, configured for directing the lathe to complete or perform one action. Based on a numerical control machining process currently executed by the machining control module 13, the interpolation section determination module 12 obtains a currently-executed program section (referred as current section hereinafter) from the memory 14, and determines whether the current section is an interpolation section and whether un-executed program sections of the numerical control machining data are interpolation sections. Hence, the machining control module 13 is controlled to obtain one program section according to determination results. The arc transition module 11 is enabled or disabled in response to the determination results of the interpolation section determination module 12.
In this embodiment, the interpolation section determination module 12 sets a flag according to the determination results. The flag indicates whether there is an interpolation section. Details will be described below.
When the current section is not an interpolation section, the interpolation section determination module 12 further determines whether there exists un-transmitted interpolation section among the numerical control machining data needed to machines components. And when there doesn't exist un-transmitted interpolation section, the interpolation section determination module 12 transmits the current section to the machining control module 13. The machining control module 13 sends a corresponding control command to the numerical control execution module 15 based on the current section, such that the numerical control execution module 15 drive the lathe to perform a corresponding machining operation. Meanwhile, the flag is not set by the interpolation section determination module 12. At this time, the arc transition module 11 is disabled.
When the current section is not an interpolation section, and there exists un-transmitted interpolation section of the numerical control machining data, the interpolation section determination module 12 transmits the current section to the machining control module 13, and meanwhile sets the flag as 0. At this time, the arc transition module 11 is enabled.
When the current section is an interpolation section, and there does not exist un-transmitted interpolation section of the numerical control machining data, the interpolation section determination module 12 transmits the current section to the machining control module 13, and meanwhile set the flag as 1. At this time, the arc transition module 11 is enabled.
When the current section is an interpolation section, and there exists un-transmitted interpolation section of the numerical control machining data, the interpolation section determination module 12 directly control the arc transition module 11 to be enabled. The arc transition module 11 determines whether a machining type described by the current section is one of preset arc transition types. In this embodiment, the preset arc transition types includes that a type in which a line track segment is exteriorly connected to the transitional arc, a type in which a line track segment inscribes the transitional arc, a type in which an arc track segment is exteriorly connected to the transitional arc, a type in which an arc track segment is interiorly connected to the transitional arc, and a first arc track segment and a second arc track segment is interiorly and exteriorly connected to the transitional arc, respectively.
When the machining type described by the current section isn't one of the preset arc transition types, the interpolation section determination module 12 stores the current section into a previous section, meaning that it omits the current section. When the machining type described by the current section is one of the preset arc transition types, the arc transition module 11 adds an arc track segment corresponding to the one of the preset arc transition types.
The arc track segment is stored into the memory 14 in advance. The arc transition module 11 obtains the arc track segment according to the determined arc transition types.
The machining control module 13 generates a control command based on the added arc track segment to call the machining execution module 15 to drive the lathe to perform a corresponding machining operation on the arc transitional section. As mentioned above, the CNC machining system 10 adds the arc track segment according to a machining type described by the current section, and then complete arc transition between any machining sections.
The principle for determining what the arc transition type it is and the algorithm for determining the track segment of an arc are described in accompanying with the preset arc transition types.
Referring to
When ∠ABO3>90°, the position relationship between the first track segment AB and the second track segment BC is that the first track segment AB is exteriorly connected to the second track segment BC.
Wherein (xA, yA) denotes a coordinate of point A and (xB, yB) denotes a coordinate of point B, which are known.
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (2):
L
32=√{square root over ((yO3−yO2)2+(xO3−xO2)2)}=R3+R2 (4)
(xO3, yO3) denotes coordinate of the circle center O3, R3 is a radius of the circle O3 and R2 is a radius of the circle O2, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate (xO2, yO2) of the circle center O2 is calculated by both formula (1) and formula (4).
As mentioned above, the calculated coordinate (xO2, yO2) of the circle center O2 has four sets of solutions. Furthermore, a screening condition is set to obtain a final value of the coordinate (xO2, yO2) from the four sets of solutions. The screening condition is that the direction from point B to point C of the arc BC is set as a positive direction after the circle centers O3 and O2 are connected, such that a solution which makes a value of ∠BO3O2 minimum is determined as what is needed, and thus the coordinate (xO2, yO2) of the circle center O2 is determined finally.
Then, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (3) and (4).
√{square root over ((yO3−yB)2+(xO3−xB)2)}=√{square root over ((yO3−yF)2+(xO3−xF)2)}=R3 (2)
√{square root over ((yO2−yE)2+(xO2−xE)2)}=√{square root over ((yO2−yF)2+(xO2−xF)2)}=R2 (3)
Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
Referring to
When ∠BO3<90°, the position relationship between the first track segment AB and the second track segment BC is that the first track segment AB circumscribes the second track segment BC.
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (5):
L
32=√{square root over ((yO3−yO2)2+(xO3−xO2)2)}=R3−R2 (5)
(xO3, yO3) denotes coordinate of the circle center O3, R3 is a radius of the circle O3 and R2 is a radius of the circle O2, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate (xO2, yO2) of the circle center O2 is then calculated by the formulas (1) and (5) together.
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has four sets of solutions. Furthermore, a screening condition is set to obtain a final value of the coordinate (xO2, yO2) from the four sets of solutions. The screening condition is that the direction from point B to point C of the arc BC is set as a positive direction after the circle centers O3 and O2 are connected, such that a solution which makes a value of ∠BO3O2 minimum is determined as what is needed, and thus the coordinate (xO2, yO2) of the circle center O2 is determined finally.
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has four sets of solutions. Furthermore, a screening condition is set to obtain a final value of the coordinate (xO2, yO2) from the four sets of solutions. The screening condition is that the direction from point B to point C of the arc BC is set as a positive direction after the circle centers O3 and O2 are connected, such that a solution which makes a value of ∠BO3O2 minimum is determined as what is needed, and thus the coordinate (xO2, yO2) of the circle center O2 is determined finally.
Then, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (2) and (3).
√{square root over ((yO3−yB)2+(xO3−xB)2)}=√{square root over ((yO3−yF)2+(xO3−xF)2)}=R3 (2)
√{square root over ((yO2−yE)2+(xO2−xE)2)}=√{square root over ((yO2−yF)2+(xO2−xF)2)}=R2 (3)
Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
Further, when following cases occurs, the needed transitional arc cannot be obtained using the afore-mentioned formulas.
Case 1: a length of line BE is larger than a length of line AB. In this case, the line AB is too short to draw a transitional radius between the line and the arc to form a transitional arc.
Case 2: central angle ∠BO1F is greater than central angel ∠BO1C corresponding to a given arc CF when obtaining the point F of the transitional arc EF. In this case, the given arc CF is too short to draw a transitional radius between the line and the arc to form a transitional arc.
Case 3: if height formed when the given arc CF is cut by the given straight line AB is twice smaller than a central radius of the transitional arc. In this case, no enough face is determined to form a transitional arc.
Referring to
As a selected direction vector gets through the first track segment AB and the second track segment BC, and the rotary direction of ∠O1BO3 is opposite to that of ∠ABC, it is determined that the rotary direction of the first track segment AB is same with that of the second track segment BC and the position relationship therebetween is that the first track segment AB is exteriorly connected to the second track segment BC.
A distance between the circle center O1 and the circle center O2 is calculated with a following formula (6):
L
12
=R
1
+R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (6).
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (7):
L
32
=R
2
+R
3=√{square root over ((xO2−xO3)2+(yO2−yO3)2)} (7),
(xO1, yO1) denotes coordinate of the circle center O1, R1 is a radius of the circle O1, R2 is a radius of the circle O2, (xO3, yO3) denotes coordinate of the circle center O3, and R3 is a radius of the circle O3, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate of the circle center O2 is calculated with the formulas (6) and (7).
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has two sets of solutions. A screening condition is set to finally determine the coordinate (xO2, yO2) of the circle center O2, which is that one solution which is nearer to the intersection point B is used as the coordinate (xO2, yO2) of the circle center O2.
Then, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (8)-(10).
√{square root over ((yO1−yE)2+(xO1−xE)2)}=R1 (8)
√{square root over ((yO3−yF)2+(xO3−xF)2)}=R3 (9)
√{square root over ((yO2−yF)2+(xO2−xF)2)}=√{square root over ((yO2−yE)2+(xO2−xE)2)}=R2 (10).
Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
Referring to
As a selected direction vector gets through the first track segment AB and the second track segment BC, and the rotary direction of ∠O1BO3 is same with that of ∠ABC, it is determined that the rotary direction of the first track segment AB is same with that of the second track segment BC and the position relationship therebetween is that the first track segment AB is interiorly connected to the second track segment BC.
A distance between the circle center O1 and the circle center O2 is calculated with a following formula (11):
L
12
=R
1
−R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (11)
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (12):
L
32
=R
3
−R
2=√{square root over ((xO3−xO2)2+(yO3−yO2)2)} (12)
(xO1, yO1) denotes coordinate of the circle center O1, R1 is a radius of the circle O1, (xO3, yO3) denotes coordinate of the circle center O3, and R3 is a radius of the circle O3, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate of the circle center O2 is calculated with the formulas (11) and (12).
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has two sets of solutions. A screening condition is set to finally determine the coordinate (xO2, yO2) of the circle center O2, which is that one solution which is nearer to the intersection point B is used as the coordinate (xO2, yO2) of the circle center O2.
Similarly, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (8)-(10). Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
Referring to
Whether a known arc is a top-arc or bottom-arc is determined according to a convex direction of a known arc (which is the first track segment AB or the second track segment BC). The top-arc is an arc which inscribes the transitional arc. The bottom-arc is an arc which is exteriorly connected to the transitional arc.
In specific, the convex direction is defined as follows. Taking arc BC as an example, any one point Mon the arc BC is selected except for end points, and point B is connected to points M and C respectively. If the position which BM is located may be obtained by rotating BC with θ(0˜90°) clockwise, the arc BC is called as a clockwise convex for the point B. In other word, the convex direction of the arc BC is clockwise for the point B. Obviously, in this case, the direction of the arc BC is same with that of the arc AB.
For the arc AB (of which circle center is O1 and radius is R1) and the arc BC (of which circle center is O3 and radius is R3) which are adjacent, the direction (i.e. rotary direction) of ∠O1BO3 formed by connecting the point B to O1 and O3 is same with the directions of the two arcs which are intersected at the point B, the arc AB is the bottom-arc of a transitional circle, and the arc BC is the top-arc. The relationships between distances L12 and L32 and a radius R2 of the transitional circle, the radiuses R1 and R3 are listed as follows.
L
12
=R
1
+R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (13)
L
32
=R
3
−R
2=√{square root over ((xO3−xO2)2+(yO3−yO2)2)} (14).
On the contrary, the relationships are listed as follows.
L
12
=R
1
−R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (15)
L
32
=R
3
+R
2=√{square root over ((xO3−xO2)2+(yO3−yO2)2)} (16).
Therefore, when the transitional arc EF inscribes the top-arc EC and is exteriorly connected to the bottom-arc AB, the coordinate of the circle center O2 is calculated with the formulas (13) and (14) or (15) and (16).
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has two sets of solutions. A screening condition is set to finally determine the coordinate (xO2, yO2) of the circle center O2, which is that one solution which is nearer to the intersection point B is used as the coordinate (xO2, yO2) of the circle center O2.
Similarly, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (8)-(10). Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
In addition, when a case occurs, the needed transitional arc cannot be obtained using the afore-mentioned formulas. In the case where the two arcs are interiorly connected or mixed to be connected, if the radius of the transitional circle is set too largely, a complex solution will occur, meaning there is no solutions and the radius of the transitional circle needs to be adjusted.
Referring to
In block S20: the interpolation section determination module 12 determines whether currently-executed program section data are interpolation section data when the CNC machining system 10 performs numerical control machining on a component after initiating. Block S21 will be executed when it is. Otherwise, block S25 will be executed.
In the block S21: the interpolation section determination module 12 determines whether un-executed program section data are interpolation section data. Block S22 will be executed when it is. Otherwise, block S28 will be executed.
In the block S22: the arc transition module 11 is enabled in response to a determination result of the interpolation section determination module 12, and determines whether a machining type described by currently-executed program section data is one of preset arc transitional types. Block S23 will be executed when it is. Otherwise, block S29 will be executed.
In this embodiment, the preset arc transition types includes that a type in which a line track segment is exteriorly connected to the transitional arc, a type in which a line track segment inscribes the transitional arc, a type in which an arc track segment is exteriorly connected to the transitional arc, a type in which an arc track segment is interiorly connected to the transitional arc, and a first arc track segment and a second arc track segment is interiorly and exteriorly connected to the transitional arc, respectively.
In the block S23: the arc transition module 11 adds data for an arc track segment corresponding to the one of the preset arc transition types into numerical control machining data.
The data for the arc track segment is stored into the memory 14 in advance. The arc transition module 11 obtains the arc track segment according to the determined arc transition types.
Referring to
In sub-block S230: data of a first track segment AB and a second track segment BC that are adjacent before planning are acquired, wherein the first track segment AB and the second track segment BC are intersected to form a corner.
Point B is the intersection point of the first track segment AB and the second track segment BC.
In sub-block S231: a position relationship between the first track segment AB and the second track segment BC is determined according to the acquired data.
The position relationship may be at least one of the following: the one that the first track segment AB is exteriorly connected to the second track segment BC, and the one that the first track segment AB inscribes the second track segment BC.
In specific, when the first track segment AB is a straight line and the second track segment BC is an arc, the position relationship between the first track segment AB is a straight line and the second track segment BC is determined as the one that the first track segment AB is exteriorly connected to the second track segment BC or the one that the first track segment AB inscribes the second track segment BC, by comparing the angle formed by the first track segment AB and the circle center O3 of the second track segment BC with a right angle.
When both the first track segment AB and the second track segment BC are arcs, it is determined whether the rotary direction of the first track segment AB is same with that of the second track segment BC and the position relationship therebetween is that the first track segment AB is exteriorly connected to or inscribes the second track segment BC, based on whether a selected direction vector gets through the first track segment AB and the second track segment BC, and whether the rotary direction of ∠O1BO3 formed by circle centers and point B is same with that of ∠ABC.
In sub-block S232: a distance L between circle centers is calculated based on the position relationship, a radius R2 of a transitional arc EF and a radius R of at least one of the first track segment AB and the second track segment BC.
When the first track segment AB is a straight line and the second track segment BC is an arc, distance L32 is calculated with the acquired position relationship, radius R2 of the transitional arc EF and the radius R3 of the second track segment BC. When both the first track segment AB and the second track segment BC are arcs, distances L12 and L32 are calculated with the acquired position relationship, radius R2 of the transitional arc EF, the radius R1 of the first track segment AB and the radius R3 of the second track segment BC.
In sub-block S233: a coordinate (xO2, yO2) of a circle center O2 of the transitional arc EF is calculated with the distance L and a coordinate of a circle center O.
In specific, When the first track segment AB is a straight line and the second track segment BC is an arc, distance L32 is calculated with the acquired position relationship, radius R2 of the transitional arc EF and the radius R3 of the second track segment BC, and then the coordinate (xO2, yO2) of a circle center O2 of the transitional arc EF is calculated with the distance L32 and the circle center O3 of the second track segment BC.
When both the first track segment AB and the second track segment BC are arcs, distances L12 and L32 are calculated with the acquired position relationship, radius R2 of the transitional arc EF, the radius R1 of the first track segment AB and the radius R3 of the second track segment BC, and then the coordinate (xO2, yO2) of a circle center O2 of the transitional arc EF is calculated with the distances L12 and L32, the circle center O2 of the first track segment AB and the circle center O3 of the second track segment BC.
In sub-block S234: coordinates (xE, yE) and (xF, yF) of end-points E and F are calculated with the radius R2 and the coordinate of the circle center O2, such that data of a track segment of the transitional arc EF is derived.
In sub-block S235: the corner is planned as data for numerical control machining path by combining the data of the track segment of the transitional arc EF and the data of the first track segment AB and the second track segment BC.
Further, the principle for determining what the arc transition type it is and the algorithm for determining the track segment of an arc are described in accompanying with the preset arc transition types.
As shown in
When ∠ABO3>90°, the position relationship between the first track segment AB and the second track segment BC is that the first track segment AB is exteriorly connected to the second track segment BC.
Wherein (xA, yA) denotes a coordinate of point A and (xB, yB) denotes a coordinate of point B, which are known.
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (2):
L
32=√{square root over ((yO3−yO2)2+(xO3−xO2)2)}=R3+R2 (4)
(xO3, yO3) denotes coordinate of the circle center O3, R3 is a radius of the circle O3 and R2 is a radius of the circle O2, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate (xO2, yO2) of the circle center O2 is calculated by both formula (1) and formula (4).
As mentioned above, the calculated coordinate (xO2, yO2) of the circle center O2 has four sets of solutions. Furthermore, a screening condition is set to obtain a final value of the coordinate (xO2, yO2) from the four sets of solutions. The screening condition is that the direction from B to C of the arc BC is set as a positive direction after the circle centers O3 and O2 are connected, such that a solution which makes a value of ∠BO3O2 minimum is determined as what is needed, and thus the coordinate (xO2, yO2) of the circle center O2 is determined finally.
As shown in
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (5):
L
32=√{square root over ((yO3−yO2)2+(xO3−xO2)2)}=R3−R2 (5)
(xO3, yO3) denotes coordinate of the circle center O3, R3 is a radius of the circle O3 and R2 is a radius of the circle O2, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate (xO2, yO2) of the circle center O2 is then calculated by the formulas (1) and (5) together.
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has four sets of solutions. Furthermore, a screening condition is set to obtain a final value of the coordinate (xO2, yO2) from the four sets of solutions. The screening condition is that the direction from B to C of the arc BC is set as a positive direction after the circle centers O3 and O2 are connected, such that a solution which makes a value of ∠BO3O2 minimum is determined as what is needed, and thus the coordinate (xO2, yO2) of the circle center O2 is determined finally.
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has four sets of solutions. Furthermore, a screening condition is set to obtain a final value of the coordinate (xO2, yO2) from the four sets of solutions. The screening condition is that the direction from point B to point C of the arc BC is set as a positive direction after the circle centers O3 and O2 are connected, such that a solution which makes a value of ∠BO3O2 minimum is determined as what is needed, and thus the coordinate (xO2 yO2) of the circle center O2 is determined finally.
Then, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (2) and (3).
√{square root over ((yO3−yB)2+(xO3−xB)2)}=√{square root over ((yO3−yF)2+(xO3−xF)2)}=R3 (2)
√{square root over ((yO2−yE)2+(xO2−xE)2)}=√{square root over ((yO2−yF)2+(xO2−xF)2)}=R2 (3)
Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
As shown in
As a selected direction vector gets through the first track segment AB and the second track segment BC, and the rotary direction of ∠O1BO3 is opposite to that of ∠ABC, it is determined that the rotary direction of the first track segment AB is same with that of the second track segment BC and the position relationship therebetween is that the first track segment AB is exteriorly connected to the second track segment BC.
A distance between the circle center O1 and the circle center O2 is calculated with a following formula (6):
L
12
=R
1
+R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (6)
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (7):
L
32
=R
2
+R
3=√{square root over ((xO2−xO3)2+(yO2−yO3)2)} (7)
(xO1, yO1) denotes coordinate of the circle center O1, R1 is a radius of the circle O1, R2 is a radius of the circle O2, (xO3, yO3) denotes coordinate of the circle center O3, and R3 is a radius of the circle O3, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate of the circle center O2 is calculated with the formulas (6) and (7).
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has two sets of solutions. A screening condition is set to finally determine the coordinate (xO2, yO2) of the circle center O2, which is that one solution which is nearer to the intersection point B is used as the coordinate (xO2, yO2) of the circle center O2.
Then, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (8)-(10).
√{square root over ((yO1−yE)2+(xO1−xE)2)}=R1 (8)
√{square root over ((yO3−yF)2+(xO3−xF)2)}=R3 (9)
√{square root over ((yO2−yF)2+(xO2−xF)2)}=√{square root over ((yO2−yE)2+(xO2−xE)2)}=R2 (10)
Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
As shown
As a selected direction vector gets through the first track segment AB and the second track segment BC, and the rotary direction of ∠O1BO3 is same with that of ∠ABC, it is determined that the rotary direction of the first track segment AB is same with that of the second track segment BC and the position relationship therebetween is that the first track segment AB is interiorly connected to the second track segment BC.
A distance between the circle center O1 and the circle center O2 is calculated with a following formula (11):
L
12
=R
1
−R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (11)
A distance between the circle center O2 and the circle center O3 is calculated with a following formula (12):
L
32
=R
3
−R
2=√{square root over ((xO3−xO2)2+(yO3−yO2)2)} (12)
(xO1, yO1) denotes coordinate of the circle center O1, R1 is a radius of the circle O1, (xO3, yO3) denotes coordinate of the circle center O3, and R3 is a radius of the circle O3, which are all known. (xO2, yO2) denotes the coordinate of the circle center O2, which is un-known.
The coordinate of the circle center O2 is calculated with the formulas (11) and (12).
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has two sets of solutions. A screening condition is set to finally determine the coordinate (xO2, yO2) of the circle center O2, which is that one solution which is nearer to the intersection point B is used as the coordinate (xO2, yO2) of the circle center O2.
Similarly, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (8)-(10). Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
As shown in
Whether a known arc is a top-arc or bottom-arc is determined according to a convex direction of the known arc (which is the first track segment AB or the second track segment BC). The top-arc is an arc which inscribes the transitional arc. The bottom-arc is an arc which is exteriorly connected to the transitional arc.
In specific, the convex direction is defined as follows. Taking arc BC as an example, any one point Mon the arc BC is selected except for end points, and point B is connected to points M and C respectively. If the position which BM is located may be obtained by rotating BC with θ(0˜90°) clockwise, the arc BC is called as a clockwise convex for the point B. In other word, the convex direction of the arc BC is clockwise for the point B. Obviously, in this case, the direction of the arc BC is same with that of the arc AB.
For the arc AB (of which circle center is O1 and radius is R1) and the arc BC (of which circle center is O3 and radius is R3) which are adjacent, the direction (i.e. rotary direction) of ∠O1BO3 formed by connecting the point B to O1 and O3 is same with the directions of the two arcs which are intersected at the point B, the arc AB is the bottom-arc of a transitional circle, and the arc BC is the top-arc. The relationships between distances L12 and L32 and a radius R2 of the transitional circle, the radiuses R1 and R3 are listed as follows.
L
12
=R
1
+R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (13); and
L
32
=R
3
−R
2=√{square root over ((xO3−xO2)2+(yO3−yO2)2)} (14).
On the contrary, the relationships are listed as follows.
L
12
=R
1
−R
2=√{square root over ((xO1−xO2)2+(yO1−yO2)2)} (15)
L
32
=R
3
+R
2=√{square root over ((xO3−xO2)2+(yO3−yO2)2)} (16).
Therefore, when the transitional arc EF inscribes the top-arc EC and is exteriorly connected to the bottom-arc AB, the coordinate of the circle center O2 is calculated with the formulas (13) and (14) or (15) and (16).
As afore-mentioned, the calculated coordinate (xO2, yO2) of the circle center O2 has two sets of solutions. A screening condition is set to finally determine the coordinate (xO2, yO2) of the circle center O2, which is that one solution which is nearer to the intersection point B is used as the coordinate (xO2, yO2) of the circle center O2.
Similarly, the coordinates (xE, yE) and (xF, yF) of the end-points E and F are calculated respectively based on the coordinate (xO2, yO2) of the circle center O2 and following formulas (8)-(10). Therefore, an arc with the circle center O2 and end points E and F is the needed transitional arc.
In block S24: the machining control module 13 generates a control command based on numerical control machining data to call the machining execution module 15 to drive the lathe to perform a corresponding machining operation on the arc transitional section. Then the process ends.
In block S25: the interpolation section determination module 12 determines whether there exists un-transmitted interpolation section data (which is data acquired by the machining control module 13) among the numerical control machining data needed to machine components. Block S26 will be executed when there exists. Otherwise, block S27 will be executed.
In the block S26: the interpolation section determination module 12 transmits the current section data to the machining control module 13, and meanwhile sets the flag as 0. At this time, the arc transition module 11 is enabled. Then the process goes back the block S24.
In block S27: the interpolation section determination module 12 transmits the current section data to the machining control module 13. Then the process goes back the block S24.
In the block S28: the interpolation section determination module 12 transmits the current section data to the machining control module 13, and meanwhile sets the flag as 1. At this time, the arc transition module 11 is enabled. Then the process goes back the block S24.
In the block S29: the interpolation section determination module 12 stores the current section data into the previous section data, which is to omit the current section data. Then the process ends.
In the present disclosure, a numerical control machining path planning method and a numerical control machining system and method are provided. A transitional arc between machining sections is completed by adding transition between an arc and a line, and an arc and an arc, avoiding impacts on the lathe, improving machining quality and meanwhile increasing machining efficiency.
In the present disclosure, a numerical control machining path planning method and a numerical control machining system and method are provided. Whether the arc transition module is enabled is controlled by system parameters and machining commands, and arc transition data is added according to the arc transition type of the current section data and the lathe is controlled to perform machining on the transition arc when the arc transition module is enabled, increasing flexibility and improving machining efficiency.
The above description depicts merely some exemplary embodiments of the present disclosure, but those skilled in the art may make various modifications to the present disclosure without departing from the spirit and scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201510072437.0 | Feb 2015 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2016/072553 | 1/28/2016 | WO | 00 |
