JP4059734B2 - Numerical controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a numerical control device that performs machining control including a rotation axis, and suppresses a difference between a cutting tool vibration and a command value that occur during machining at a joint of a command block having a large change angle in a traveling direction and an actual movement locus. The present invention relates to a numerical control device.
[0002]
[Prior art]
For example, when a workpiece is cut by a numerical control device (NC device), the workpiece and the tool are moved relative to each other based on the command to process the workpiece. For example, when the traveling direction of the tool changes (in other words, For example, in the case of corner-shaped machining), the degree of change in the advancing direction is determined as the tool moves (in other words, corner discrimination is performed). ) And processing as directed. That is, there is a case where it is necessary to perform a deceleration process in the corner portion in order to ensure high-precision machining so as to obtain a corner shape as instructed, and there is corner discrimination as a technique used in this deceleration process. For example, if the NC command is G91 (relative movement command of workpiece and tool), G01 (cutting linear movement),
G91 G01 X10.0 F10000.0 ・ ・ ・ Linear interpolation at 10m / min for 10mm in X direction with increment value
G01 X10.0 Y0.1 ・ ・ ・ Linear interpolation 10mm in X direction and 0.1mm in Y direction
G01 X-10.0 ・ ・ ・ Linear interpolation of −10mm in the X direction
That is, the machining program draws a locus as shown in FIG. In FIG. 9, the changing angle θ between the first block and the second block₁Is small (the corners are loose), so that the machined surface can be kept smooth even when machining with the feed rate specified in F10000.0 maintained without deceleration. The angle θ₂Is large (the corner is tight), so if you do not perform the process of decelerating to a speed smaller than F10000.0, approaching the corner, and exiting the corner while accelerating, the shape of the processed corner will bend. For this reason, it is necessary to perform a process of determining corner determination for the change in angle between the first block and the second block and the change in angle between the second block and the third block.
[0003]
FIG. 10 is a block diagram showing a schematic configuration of a numerical control device equipped with this corner discrimination processing. In FIG. 10, 1 is a storage device storing a machining program, 2 is reading a machining program stored in the storage device 1, and calculates the movement start point and movement end point of each block, corner determination, etc. The program analysis unit 3 performs interpolation processing based on the movement start point and the movement end point analyzed by the program analysis unit 2, and distributes the movement amount in each axis direction. And a movement command pulse distribution unit that calculates a movement amount per movement sampling period from the acceleration / deceleration information added by the corner determination unit and outputs a movement command pulse, 5 receives a command from the movement command pulse distribution unit 4, An acceleration / deceleration unit that executes acceleration / deceleration processing on the command pulse when the movement command is moved, and 6 is a command pulse output unit that inputs a signal from the acceleration / deceleration unit 5 and outputs a command pulse. 7 is a driving unit that controls the motor 8 to be controlled by entering the command pulses from the command pulse output section 6.
[0004]
Here, the program analysis unit 2 is composed of the following three parts. That is, 21 is a program reading unit that takes a machining program and converts it into information that can be easily calculated by the numerical control device, 22 is a path generation unit that calculates the movement start point and movement end point of each block, and 23 is a movement between blocks. It is a corner discriminating unit that adds information that clamps the speed near the corner to a sufficiently small value when the corner angle change is evaluated from the vector change amount and the corner has an angle change larger than a threshold value.
[0005]
Here, a corner discrimination process in the conventional corner discrimination unit 23 will be described with reference to FIGS. FIG. 11 shows a movement vector r when moving from the first block to the second block._n-1Move vector r_nThe machining program command indicates a change from G91 G01 X20 Y10 Z10 to G01 X10 Y20 Z30. Then, the conventional corner discrimination processing is performed by cos θ = r_n・ R_n-1/ (| R_n| ＊ | r_n-1The corner angle θ is calculated by applying the cosine theorem (here, a formula representing the inner product of vectors). In FIG. 11, in the equation of cos θ, the upper equation is a so-called second cosine theorem, and the lower equation is an inner product formula, but there is no substitute for calculating the angle θ. Also, in the expression_n| Is the movement vector r_n, "·" Is the inner product of vectors, r_nThe subscript "n" means the nth block.
[0006]
Specifically, in the program command “G91; G01 X20 Y10 Z10; G01 X10 Y20 Z30;”, the movement vector r_n-1, R_nIs expressed as a component, r_n-1= (20,10,10), r_n= (10, 20, 30), and the corner angle is cos θ = r from the component display formula_n・ R_n-1/ (| R_n| ＊ | r_n-1) = (20 * 10 + 10 * 20 + 10 * 30) / (sqrt (20²+10²+10²) * Sqrt (10²+20²+30²)) = 0.7637... Here, sqrt (X) represents the square root of X.
[0007]
As a result, the corner discrimination process includes a movement vector r immediately before the block joint as shown in FIG._n-1Is acquired (step S301), and then the movement vector r immediately after the block joint is obtained._n Is acquired (step S302). Thereafter, the corner angle θ is calculated by the cosine theorem (step S303).
[0008]
[Problems to be solved by the invention]
The above description is based on the premise of processing only with linear movement. That is, in a block in which a linear movement program command for a certain axis changes abruptly, the motor output of that shaft cannot follow the command, so the determination that the vehicle must decelerate is determined using the size of the corner angle. However, in processing, there is a case where a rotation axis is provided as a movement axis. In this case, in the conventional numerical control device, the same corner determination processing is performed without dividing the corner determination method between the case where the corner determination is performed only with the linear axis and the case where the linear axis includes the rotation axis.
[0009]
However, considering the relative trajectory between the workpiece and the cutting edge of the tool, the corner angle calculated in the conventional discrimination process has the following problems when the rotation axis is included in the movement axis: The angle is calculated.
[0010]
That is, for example, when the C axis is a rotation axis and the Z axis is a moving axis that is a linear axis, the calculated corner angle is cos θ = r in the program command “G91; G01 Z100 C90; G01 Z100 C-90;”_n・ R_n-1/ (| R_n| ＊ | r_n-1) = (100 * 100 + 90 * -90) / (sqrt (100²+90²) * Sqrt (100²+90²)) = 0.10497... Therefore, the corner angle calculated by the conventional corner discrimination process always performs the same corner discrimination regardless of the shape of the tool or workpiece when the movement amount of the shaft is the same.
[0011]
However, as shown in FIG. 13, it is obvious if two types of workpieces A and B having extremely different radii are assumed, but both workpiece A and workpiece B are “G91; G01 Z100 C90; G01 Z100 C”. -90; "is executed, and the relative trajectory between the cutting edge and the workpiece, that is, the trajectory in which cutting is performed, is indicated by the arrow" 1 ▼ "," G01 Z100 C-90; " The angle θ formed by the arrows (1) and (2) is larger than that of the work B having a smaller radius due to the difference in the peripheral speed related to the shaft rotation. The larger work A is sharper. As described above, in the conventional corner discrimination, correct corner discrimination cannot be performed when the rotation axis is included.
[0012]
As a conventional example of rotating shaft control, there is a technique described in Japanese Patent Laid-Open No. 4-340604. This technique (Japanese Patent Laid-Open No. 4-340604) is intended to determine speed control, and a corner angle between blocks. Further, when the rotation axis is in an arbitrary direction on three orthogonal axes (for example, (x, y, z) = (1,2,3) described later in the present invention) It does not deal with general vector conversion, including the case of turning around an axis having a directional vector.
[0013]
Furthermore, assuming that the above-described corner determination processing has been correctly performed, when performing acceleration / deceleration processing based on the angle formed by the movement vectors of adjacent blocks, conventionally, acceleration / deceleration processing according to the shaft configuration and the shaft operation is appropriately performed. Another problem is that it does not have a switching function. In other words, the switching work based on the understanding of the axis configuration of which rotating shaft rotates around which linear axis and the operating state of which axis is currently being moved can be used for acceleration / deceleration processing. It is indispensable to reflect efficiently.
[0014]
For example, in an NC machine tool having 5 axes of X, Y, Z, B, and C (see Fig. 4), the X axis and Z axis are swung while the X axis and B axis are moving simultaneously. Since the movement in the plane is performed, the movement of X by the B-axis rotation interferes with the movement of the X-axis command that exists from the beginning, and conversion by three-dimensional vector calculation is necessary. On the other hand, when the two axes of Z and C are moving, such interference does not occur, and movement on the X and Y planes by turning the C axis and movement by command of the Z axis are performed on independent planes. Therefore, conversion by a one-dimensional scalar calculation is sufficient. Here, the interference is, for example, when the C axis moves, the C axis rotates around the Z axis, so that the coordinate value of the Z axis is not affected by the rotation of the C axis, but the X axis and the Y axis The coordinate value is said to change due to the rotation of the C axis. When the rotation of one axis affects the coordinate value of another axis as described above, it is determined that the interference occurs.
[0015]
Thus, even if the linear axis and the rotary axis are moving simultaneously as described above, the conversion of the rotary axis movement must be calculated with a three-dimensional vector, and the one-dimensional calculation can be performed. There are two types. Then, if it is possible to perform a one-dimensional calculation that can correctly convert the influence of the rotation axis only by performing a scalar calculation, performing a corner determination process using a vector calculation is the number of calculation steps. This is wasteful, and in fact, the obtained corner angle is the same whether it is a three-dimensional vector operation or a one-dimensional scalar operation.
[0016]
Further, even in a machine equipped with a rotary shaft, when the machining is performed only with the linear shaft, conversion of the rotary shaft moving amount itself is completely unnecessary.
[0017]
Thus, for the purpose of preventing calculation waste, in the acceleration / deceleration processing according to the axis configuration and the axis operation, a processing mechanism for converting the rotational axis movement amount by one-dimensional scalar calculation, and which acceleration / deceleration A processing mechanism that determines whether it is appropriate to select a process (a processing mechanism that determines whether vector calculation is necessary, scalar calculation is sufficient, or conversion itself is not necessary) is required.
[0018]
The present invention has been made in view of the above. Even when the moving shaft includes a rotating shaft, correct corner discrimination is performed, and when the controlled shaft is only a linear shaft, the rotating shaft is included. An object of the present invention is to provide a numerical control device that performs appropriate corner acceleration / deceleration.
[0019]
[Means for Solving the Problems]
  In order to achieve the above object, a numerical control device according to the present invention is a numerical control device for controlling a machine tool including both a linear shaft and a rotary shaft.AndWhen corner acceleration / deceleration processing between two consecutive blocks is performed, means for converting the movement vector of the rotation axis of the continuous block into a movement vector in an orthogonal three-axis coordinate system, and an angle calculation operation for the converted vector And a corner acceleration / deceleration processing function including a means for obtaining a corner angle.
[0020]
  Further, according to the present invention, in the above invention, the movement vector of the continuous block is directly applied to the angle calculation calculation without converting the movement vector of the rotation axis of the continuous block into the movement vector in the orthogonal triaxial coordinate system. A second means for obtaining a corner angle; a judging means for judging whether or not the movement vector is accompanied by a movement of the rotation axis; and when the judgment means judges that the movement vector is accompanied by a movement of the rotation axis, Switching to processing for performing corner acceleration / deceleration processing, and processing for performing corner acceleration / deceleration processing based on the corner angle obtained by the second means when the determination means determines that the movement vector does not involve movement of the rotating shaft And a switching means for switching to.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. First, when performing correct corner determination processing, the inventor has focused on the following when the NC apparatus performs processing in which the angle θ of the workpieces A and B is different as shown in FIG. An angle θ measured by a person who sees the cutting trajectories of the workpieces A and B is an angle obtained by observing the cutting trajectory as a movement in an orthogonal three-axis space. The measurement work in this case does not consider how the linear axis and the rotary axis moved, but how the cutting locus changed in the orthogonal 3-axis space as a result of the movement of each axis. It measures that. Since the conventional corner discrimination process does not have a means for replacing "how it moves in the orthogonal 3-axis space" when the rotation axis and the linear axis move, as described in the explanation of FIG. In addition, the angle drawn by the relative trajectory of the workpiece and the blade in the workpieces A and B cannot be calculated correctly. In other words, in order to correctly obtain the corner angle θ, a pre-process for converting the movement amount due to the rotation of the rotation shaft into the movement amount on the three orthogonal axes may be performed. Therefore, if the influence of the movement due to the rotation of the rotation axis is converted into a movement on three orthogonal axes, the converted movement vector is converted into a conventional corner discrimination process (a process for obtaining a corner angle by substituting the movement vector into the cosine theorem). ). To this end, the inventor has determined that the cutting edge point position vector r, which is the position vector of the machining point at the block seam._tAnd angular movement vector Δθ_iThe concept of the outer product is introduced, and the effect of movement due to rotation of the rotating shaft is converted to movement on three orthogonal axes.
[0028]
Embodiment 1 FIG.
FIG. 1 is a flowchart in the numerical control apparatus according to the first embodiment of the present invention. In executing this flowchart, as a specific example, a program command “G91; G01 Z100. C90 .; G01 Z100. C-90 .;” is applied to a cylindrical workpiece having a radius of 100 [mm] and a length of 300 [mm]. The case of executing is described with reference to FIG. In FIG. 2, the angle θ obtained for determining whether or not corner acceleration / deceleration is necessary is an angle formed by the joint between the second block and the third block of the program._n-1And t_nIt is the angle formed by
[0029]
In this case, the cutting edge point position vector r, which is the position vector of the machining point at the block seam_tIs the point P at the block seam from the origin in FIG._tCorresponds to the vector going to. Here, assuming that the cutting edge was at (X, Y, Z, C) = (0, 100, 0, 0) before moving this block, the position of the cutting edge point at the block seam is r_t= (0, 100, 100, 90)
[0030]
On the other hand, the direction of the rotation axis (C axis in this program example) (the C rotation center axis, that is, the Z axis in the example program) has the direction of the vector, and the magnitude of the rotation speed (program In the example, 90 [deg / min] = π / 2 [rad / min])_iIt was. Where Δθ_i Assuming that the index number i is 1 for the A axis, 2 for the B axis, and 3 for the C axis, Δθ in the second block (G01 Z100. C90.) Of this program_ThreeBecomes (0, 0, π / 2), and the A and B axes are not commanded.₁And Δθ₂Becomes (0, 0, 0). Similarly, in the third block (G01 Z100. C-90.), Δθ₁And Δθ₂Becomes (0, 0, 0) and Δθ_ThreeBecomes (0, 0, -π / 2).
[0031]
In FIG. 1, the cutting edge point position vector r in step S101._tGet first. Next, in step S102, the angular movement vector Δθ_iAsk for. In step S103, the outer product r_d= Δθ_iXr_tiAsk for. Where r_tiIs one point P on the turning center axis (Z axis) of the rotation axis in FIG._i0To r_tIt is a vector which goes to the blade point shown by. Where P_i0Can be any point as long as it is on the turning center axis.₃₀To (0, 0, 0). In this case, r_t3= (0, 100, 100)
[0032]
Δθ_i, R_tiProduct (Δθ_iXr_ti), The amount of movement due to the rotation of the rotation axis i can be converted into the amount of movement in the orthogonal three-axis space of (X, Y, Z). In this example, Δθ in the second block_Three= (0, 0, π / 2), r_t3= (0, 100, 100), so Δθ_ThreeXr_t3= (− 100π / 2, 0, 0).
[0033]
For the A-axis, B-axis, and C-axis, the converted movement amount is added for i = 1 to 3, that is, r_d= Σ (Δθ_iXr_ti) Can be converted into a vector in the orthogonal three-axis space. In this example of FIG. 2, Δθ₁= Δθ₂= (0, 0, 0), so r_d= Δθ_ThreeXr_t3It becomes.
[0034]
Then, as shown in step S104, the conversion vector r_dAnd (X, Y, Z) translation vector r obtained directly from the program axis address_lSum of r_n= R_l+ R_dThus, even when the movement includes the rotation axis, it is possible to accurately determine how the relative locus of the cutting edge point and the workpiece changes in the (X, Y, Z) orthogonal three-axis space. FIG. 3 shows the state of this vector composition._tVector r drawn by the second block in the vicinity_nIs r by linear axis movement_lAnd conversion vector r by rotation axis movement_dIt will be expressed as the sum of
[0035]
In the second block of this program, r_l= (0, 0, 100), so the relative trajectory of the cutting edge point created by the movement of the second block and the workpiece at the joint between the second block and the third block is r_n= (− 100π / 2, 0, 100). Similarly, the relative trajectory on the third block side is r_n= (100π / 2, 0, 100). In order to make the identification easy to understand, the relative trajectory of the second block will be expressed as r._n-1, The relative trajectory of the third block is r_nAnd
[0036]
As a result, in step S105, the corner angle equation cos θ = r_n・ R_n-1/ (| R_n| ＊ | r_n-1) To calculate the corner angle. In this program example, cos θ = −0.3355... And a desired corner angle is calculated.
[0037]
As an example of calculating the corner angle according to the flowchart of FIG. 1, the simplest case where only the Z axis and the C axis move as described above has been described. However, this flowchart simultaneously includes five or more axes including two or more rotation axes. It can also be applied when moving. For example, as in the coordinate axis configuration shown in FIG. 4, the program command “G90 G01 X0. Y0. Z0. B0. C0 .; G01 X100. Y100. Z100. B-45” C90 .; G01 X-100. Y200. Z200. B30. C-90 .; ”, the movement vector in the orthogonal three-axis space of (X, Y, Z) Can be converted.
[0038]
A method for calculating the corner angle at the joint between the second block and the third block will be described below based on this program command. A feature of the coordinate system of FIG. 4 is that the B axis and the C axis are centered on the Y axis and the Z axis, respectively. That is, the feature is that the turning center of the rotation axis is an axis passing through the origin.
[0039]
First, the cutting edge point position vector r in step S101_tIs (X, Y, Z) = (100, 100, 100). In step S102, the angular movement vector Δθ on the second block side_iIs Δθ₁= (0, 0, 0), Δθ₂= (0, −π / 4, 0), Δθ_Three= (0, 0, π / 2). Similarly, Δθ on the third block side_iIs Δθ₁= (0, 0, 0), Δθ₂= (0, π / 6, 0), Δθ_Three= (0, 0, -π / 2). Further, in step S103, the vector r from the turning center axis toward the cutting edge point_tiIs P₂₀For (0, 100, 0)_t2= (100, 0, 100), P₃₀To (0, 0, 100)_t3= (100, 100, 0) r_t1For the second and third blocks, Δθ₁= 0 so there is no need to think about it. At this time, the outer product r on the second block side_dIs r from the component calculation formula by outer product_d= Σ (Δθ_iXr_ti) = (Δθ₂Xr_t2 + Δθ_ThreeXr_t3) = (− 300π / 4, 100π / 2, 100π / 4). Similarly, outer product r on the third block side_dIs r_d= (500π / 6, −100π / 2, 100π / 6). In step S104, the second block vector r_l R_l= (100, 100, 100), (−100, 200, 200) in the third block. The subsequent processing is the same regardless of the machining program._n= R_l+ R_dIn step S105, a corner angle is obtained. Thus, the present invention can also be applied to the case of simultaneous 5-axis control.
[0040]
Furthermore, as a general case, it passes through the turning center axis (x, y, z) = (10,20,30) of the rotating workpiece, and the direction of (x, y, z) = (1,2,3) Consider any axis of rotation. Assuming that this rotation axis is called the W axis, the program command "G90 G01 X0. Y0. Z50. W0 .; G01 X100. Y100. Z150. W-180 .; G01 X-100. Y200. Z250. W180 .;" The angle formed by the second block and the third block when executed is calculated. Here, if the tool being used has a length of 50 in the Z direction, the cutting edge point position vector r_t= (r_tx, r_ty, r_tz) = (0, 100, 100).
[0041]
In this case, the angular movement vector Δθ in step S102 of FIG._iIf the index number i for the W-axis is 1, Δθ in the second block in the W-axis direction₁= (− Π / sqrt (14), −2π / sqrt (14), −3π / sqrt (14)), Δθ₂= Δθ_Three= Δθ_Four= Δθ... = (0, 0, 0). Similarly, in the third block, Δθ₁= (π / sqrt (14), 2π / sqrt (14), 3π / sqrt (14)), Δθ₂= Δθ_Three= Δθ_Four= Δθ... = (0, 0, 0).
[0042]
P_TenIs (10, 20, 30), the vector from the swivel center axis to the cutting edge is r_t1= (90, 80, 70) At this time, the outer product r on the second block side_dIs r_d= Σ (Δθ_iXr_ti) = (Δθ₁Xr_t1) = (100π / sqrt (14), −200π / sqrt (14), 300π / sqrt (14)). Similarly, outer product r on the third block side_dIs r_d= (− 100π / sqrt (14), 200π / sqrt (14), −300π / sqrt (14)).
[0043]
In step S104, the second block r_l= (100, 100, 100), the third block is r_l= (−200, 100, 100) and sum r_n= R_l+ R_dAsk for. In step S105, a corner angle is obtained. Thus, it is possible to provide a corner angle calculation means that can correspond to an arbitrary axis configuration.
[0044]
Embodiment 2. FIG.
Next, a numerical controller having a corner acceleration / deceleration process for multiplying the moving amount of the rotary shaft by a magnification in the second embodiment will be described. In the first embodiment (numerical control device that performs corner acceleration / deceleration processing using vector conversion), the influence of the rotation axis on the change in the relative trajectory of the workpiece and the cutter is calculated using a three-dimensional vector. In general, a relative trajectory can be calculated for an NC device having any axis configuration. However, for example, in an NC consisting of one rotation axis (C axis) and two linear axes (X, Z axes), when the workpiece size (radius) is known when moving only with Z and C, In some cases, it is possible to appropriately calculate the influence of the rotation axis only by performing one-dimensional multiplication on the movement amount of the rotation axis. In this case, the change in the relative trajectory between the workpiece and the tool caused by moving the rotation axis (C axis) and the change in the relative trajectory caused by moving the Z axis are the change in the XY plane and the change in the Z axis. Separated into changes in Therefore, the amount of movement obtained by multiplying the amount of movement of the rotation axis by the radius of the workpiece matches the actual amount of change in the relative trajectory on the XY plane. In other words, since the influence of the rotation axis can be correctly converted simply by performing a scalar calculation of multiplying the movement amount of the rotation axis, the conventional cosine theorem can be used to calculate the movement amount multiplied by this radius and the Z-axis movement amount. By substituting in the calculation formula, it is possible to calculate the same angle as the result in the case of using the first embodiment (a numerical control device that performs corner acceleration / deceleration processing using vector conversion).
[0045]
FIG. 5 is a flowchart for realizing the second embodiment (a numerical control apparatus having a corner acceleration / deceleration process for multiplying the moving amount of the rotary shaft by a magnification). The program command “G91; G01 Z100. C90 .; G01 Z100. C-90 .;” will be described as an example. In FIG. 5, according to S1001, a certain magnification is applied to the movement amount of the rotation axis (C-axis in this program). In general, it is appropriate to use a value proportional to the radius of the workpiece. Here, it is assumed that the magnification is set to 3 as a result of measuring the workpiece in advance. At this time, the movement vector of the second block is r_n-1= (Z, C) = (100, 270), the third block is r_n= (Z, C) = (100, -270).
[0046]
Next, in step S1002, cos θ = r_n・ R_n-1/ (| R_n| ＊ | r_n-1) To calculate the corner angle. In this example, cos θ = −0.7587.
[0047]
Embodiment 3 FIG.
Next, a third embodiment of the present invention (numerical control device that switches the magnification of the rotational axis movement amount) will be described. In the second embodiment, the method of selecting the magnification to be multiplied by the movement of the rotating shaft is proportional to the radius of the workpiece. However, the influence of the delay in motor output and the difference in hardness depending on the workpiece direction is empirically determined. When grasping, it is possible to process with higher accuracy by using a specific magnification. For this reason, it is necessary to arbitrarily set the magnification by a parameter or a program. FIG. 6 is a corner acceleration / deceleration process when the magnification calculation part of the third embodiment is installed, and FIG. 7 is a flowchart of the magnification calculation part. Hereinafter, FIG. 7 will be described.
[0048]
In step S1201, it is determined whether or not it is in a mode in which the NC apparatus automatically calculates the magnification (referred to as a magnification automatic calculation mode), and the subsequent processing is divided. This mode ON / OFF can be realized by providing an NC internal variable as a flag, and for example, by adding a function such as incremental value / absolute value switching. Here, ON / OFF is controlled by a program.
[0049]
If the automatic magnification calculation mode is ON in step S1201, the magnification calculation shown in step S1202 is performed. Here, the distance between the cutting edge point and each rotation axis is calculated, and (distance × π / 180) is set as the magnification. For example, in the case of an NC machine tool that has 5 axes of X, Y, Z, B, and C and the tool rotates around the B axis, the distance corresponding to the B axis corresponds to the tool length and the C axis. The distance is sqrt (X²+ Y²(However, X, Y, and Z are the X, Y, and Z coordinates of the cutting edge, respectively). In this NC machine tool, when the program command “G91; G01 Z100. C90 .; G01 Z100. C-90 .;” is described, the cutting edge is set to (X, Y, Z, B at the start of the program. , C) = (30, 40, 0, 90, 0). At the joint between the second block and the third block of the program, the rotation axis that moves is only the C axis, and the distance between the C axis and the cutting edge is sqrt (30²+40²) = 50. Therefore, the magnification corresponding to the C axis is (distance × π / 180) = (50 × π / 180).
[0050]
If the automatic magnification calculation mode is OFF in step S1201, the condition judgment shown in step S1203 is performed. For example, when the code for designating the magnification is “M2001 P_Q_R_;”, and P, Q, and R are the magnifications corresponding to the A, B, and C axes, respectively, in the mode of M2001 in step S1203, The magnification setting shown in step S1204 is performed. In step S1204, the numerical values designated by the P, Q, and R addresses are set as the magnification of each rotation axis.
[0051]
If the program is not designated in step S1203, the magnification setting shown in step S1205 is performed. In this process, the magnification previously registered in the NC as a parameter is set as the magnification of each rotation axis.
[0052]
By the processes in steps S1201 to S1205 described above, the magnification with respect to the movement amount of the rotating shaft can be obtained.
[0053]
Embodiment 4 FIG.
Next, a numerical controller that can change the acceleration / deceleration processing used according to the axis configuration of the control target axis according to the fourth embodiment will be described. FIG. 8 is one of flowcharts for realizing the fourth embodiment. In FIG. 8, first, in step S1301, information regarding the control axis is acquired. The information here is information such as which axis is the rotation axis and which is the turning center axis corresponding to the rotation axis (for example, the axis corresponding to the C axis is the Z axis).
[0054]
In step S1302, the control axis information obtained in step S1301 is collated with information relating to the movement axis of the read machining program, and it is determined whether or not the rotary axis moves before and after the block joint of the machining program. Sort out. If there is no rotation axis in step S1302, the useless process of calculating the influence of the rotation axis is omitted, and the corner acceleration / deceleration process (3) in step S1306 is called. This acceleration / deceleration process {circle around (3)} is a conventional corner acceleration / deceleration process that does not consider the type of shaft, and for example, a method using the cosine theorem introduced in the prior art is applicable. On the other hand, when the rotation axis moves, the determination processing routine of step S1303 is called.
[0055]
In step S1303, it is determined whether or not the rotation axis movement command and the linear axis movement command interfere. As the combinations of the interfering axes, there are a combination of 1: A axis and Y, Z axis 2: B axis and Z, X axis 3: C axis and X, Y axis. Therefore, when an interfering axis is commanded in the same block, such as “G01 X100. C200.”, It is determined that the movement command is “interfering”.
[0056]
If the interference of the axis movement occurs in step S1303, the correct corner acceleration / deceleration cannot be performed unless the influence of the rotation axis movement is converted into the movement vector on the three orthogonal axes. Call the indicated corner acceleration / deceleration process (1). This corner acceleration / deceleration process (1) is a corner acceleration / deceleration process using vector conversion. If no interference occurs, the movement of the rotation axis can be treated as an independent linear axis, and the corner acceleration / deceleration process (2) shown in step S1305 is called. This corner acceleration / deceleration process {circle around (2)} is a corner acceleration / deceleration process for multiplying the moving amount of the rotary shaft by a magnification.
[0057]
In this way, through the corner acceleration / deceleration processing shown in steps S1304 to S1306, it is determined whether deceleration is necessary near the corner. Based on the determination result, the moving speed commanded to the motor is determined in step S1307.
[0058]
【The invention's effect】
As described above, according to the present invention, in a numerical control apparatus including a rotation axis as a movement control axis, when corner acceleration including movement of the rotation axis is performed, the movement vector of the rotation axis in the adjacent block is orthogonal. Even if the moving axis includes a rotation axis by having a corner acceleration / deceleration processing function including means for converting to a movement vector in three axes and means for obtaining a corner angle by applying the converted vector to an angle calculation calculation. The relative trajectory of the workpiece and the cutter, that is, the corner angle actually drawn by the machining point can be calculated, and correct corner discrimination can be performed.
[Brief description of the drawings]
FIG. 1 is a flowchart illustrating a processing procedure according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining handling of variables when converting a movement vector of a rotation axis into a movement vector of three orthogonal axes.
FIG. 3 is a diagram for explaining a state of vector synthesis;
FIG. 4 is a diagram for explaining how to take coordinate axes in a specific example;
FIG. 5 is a flowchart showing a processing procedure according to the second embodiment of the present invention.
6 is a flowchart showing a processing procedure when the third embodiment is installed in the flowchart of FIG. 5. FIG.
FIG. 7 is a flowchart illustrating a processing procedure according to the third embodiment.
FIG. 8 is a flowchart showing a processing procedure for realizing the fourth embodiment.
FIG. 9 is a diagram illustrating corner angles.
FIG. 10 is a block diagram showing a schematic configuration of a numerical controller (CNC) equipped with a corner acceleration / deceleration function.
FIG. 11 is a diagram for supplementing how to use the cosine theorem in a conventional corner acceleration / deceleration method.
FIG. 12 is a flowchart of a corner acceleration / deceleration method using a conventional cosine theorem.
FIG. 13 is a diagram for explaining a problem of a conventional corner acceleration / deceleration method.
[Explanation of symbols]
2 program analysis unit, 21 program reading unit, 22 path generation unit, 23 corner discrimination unit, r_n, R_n-1  Moving vector, r_t  Cutting edge point position vector, Δθ_i  Angular movement vector, r_d  Outer product.

Claims (2)

In a numerical control device for controlling a machine tool including both a linear axis and a rotary axis,
When corner acceleration / deceleration processing between two consecutive blocks is performed, means for converting the movement vector of the rotation axis of the continuous block into a movement vector in an orthogonal three-axis coordinate system, and an angle calculation operation for the converted vector And a corner acceleration / deceleration processing function including means for obtaining a corner angle by applying to the above. Second means for obtaining a corner angle by directly applying the movement vector of the continuous block to the angle calculation calculation without converting the movement vector of the rotation axis of the continuous block into a movement vector in an orthogonal three-axis coordinate system;
Determining means for determining whether or not the movement vector is accompanied by movement of the rotation axis;
When it is determined by the determination means that the movement vector is accompanied by the movement of the rotation axis, the processing is switched to the processing for performing the corner acceleration / deceleration processing, and the determination means is determined not to be accompanied by the movement of the rotation axis. Switching means for switching to processing for performing corner acceleration / deceleration processing based on the corner angle obtained by the second means;
The numerical control device according to claim 1, comprising:

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