JP5317532B2 - Numerical controller - Google Patents

Description

  The present invention relates to a numerical control apparatus for controlling the operation of a moving body by sequentially executing a plurality of operation commands instructed by an NC program, and in particular, when shifting from the current operation to the next operation, This is related to the in-position check control for starting the next operation when the positioning of the operation reaches a predetermined range with respect to the target position.

  In general, a numerical control device (NC device) controls a series of motions of a machine tool by sequentially executing the read NC program one block (row) at a time. For example, in a machine tool for machining parts, moving to a tool change position for tool change, tool change, tool rotation, positioning to a process start position (approach), start of cutting feed, machining a predetermined shape, Processing is performed by instructing the program to perform a series of operations (motion) such as returning, stopping the rotation of the tool, and returning to the original position, and sequentially executing each command.

  For example, consider a case where a series of operations are performed in accordance with a program composed of two blocks N1 and N2 as shown in FIG. Here, N1 and N2 are sequence numbers described for each block (row). In the first block N1, X100. Positioning operation (G0), the second block N2 has Y100. The positioning operation (G0) is commanded. This series of operations has a path shown in FIG. 19 on the XY plane, where the initial position is the origin. Here, the point P is the end point of the positioning operation commanded to the block N1.

  Here, at the point P, for example, as disclosed in the following document, if the positioning of the block N1 reaches a range of a predetermined required accuracy (allowable error = in-position width) with respect to the target position, Control such as starting the movement of the next N2 block is normally performed (see, for example, Patent Document 1).

  The speed waveform of this operation is shown in FIG. Here, the horizontal axis t is time, and Vx and Vy are speeds in the X-axis and Y-axis directions, respectively. In the figure, when the remaining distance to the end point P of the movement in the X-axis direction, which is the positioning operation of N1, falls within the predetermined required accuracy (L1) (time t1b), the next positioning operation of N2 A movement in a certain Y-axis direction is started. Before the actual operation of N1 is completely completed (time t1), the next operation is started to shorten the cycle time, and the motion error at that time is compared to the target position as shown in FIG. Thus, control is performed so as to be within the range of the required accuracy (L1).

Japanese Patent Laid-Open No. 11-58177

  However, in the conventional technique, when moving from a certain operation (referred to as operation 1) to the next operation (referred to as operation 2), the next movement (operation 2) starts based on the remaining distance of operation 1. Since the timing is determined, the range in which the timing can be adjusted is limited, and various start timings cannot be controlled. In particular, the conventional technique cannot perform control to sufficiently shorten the cycle time while maintaining a predetermined accuracy.

  The present invention has been made in view of the above, and enables a start timing control method with a higher degree of freedom than is possible with the conventional method of determining the start timing of the next operation based on the remaining distance of the current operation. An object of the present invention is to provide a numerical control device that enables various operations according to the purpose, and in particular, to provide a numerical control device that further shortens the cycle time while maintaining accuracy.

  In order to solve the above-described problems and achieve the object, a numerical control device according to the present invention is a numerical control device that controls the operation of a moving body by sequentially executing a plurality of operation commands instructed by a program. An analysis processing unit that analyzes an operation command instructed to generate analysis data, a timing control unit that determines an operation start timing of the next operation based on the analysis data and pre-stored interpolation / acceleration / deceleration parameters; Interpolation / acceleration / deceleration unit that generates position command to perform interpolation / acceleration / deceleration according to analysis data, interpolation / acceleration / deceleration parameters, and operation start timing, and servo control unit that servo-controls drive unit to follow position command The timing controller calculates the time when the current operation is completed or the time when the remaining distance to the target position of the current operation matches the end point allowable error. Distance next operation moves found in the calculated time, so that the less tolerance and obtains the operation start timing.

  According to the present invention, the timing control unit calculates the time when the current operation is completed or the time when the remaining distance to the target position of the current operation matches the end point allowable error, and the distance that the next operation moves is calculated. At this time, the operation start timing is obtained so as to be less than the allowable error, so that the start timing with a higher degree of freedom than the conventional method of determining the start timing of the next operation based on the remaining distance of the current operation is not possible. It enables a control method and various operations according to the purpose. In consideration of the movement of the next movement, the accuracy of the movement of the next movement can be limited to an allowable error or less, and the type of the next movement command (speed, movement distance, movement direction) Etc.), the accuracy can be maintained within an appropriate range. Moreover, even if it is a case where it is going to give an excessive precision, there exists an effect that cycle time does not become long.

  Embodiments of a numerical controller according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing the overall configuration of a numerical control apparatus according to an embodiment of the numerical control apparatus of the present invention. In FIG. 1, the numerical control apparatus 100 includes an analysis processing unit 102, an interpolation / acceleration / deceleration unit 104, a timing control unit 105, and a servo control unit 108. The analysis processing unit 102 reads an NC program (machining program, motion program) 101, analyzes an operation command (positioning, cutting feed, etc.) described in the read NC program 101, and generates analysis data 103 for each block. . The analysis data 103 is obtained as a result of interpreting the command of each block, movement mode for each block (distinguishing between positioning, cutting feed, etc.), movement distance, movement direction, interpolation mode (straight line, circular arc, non-interpolation, etc.) , Information about movement speed and other operations. When it is necessary for the timing control unit 105 described later to refer to the next movement information, the NC program 101 is prefetched and buffered by a necessary number of blocks.

  The interpolation / acceleration / deceleration unit 104 performs interpolation / acceleration / deceleration in accordance with the generated analysis data 103 and the interpolation / acceleration / deceleration parameter 110 set in the storage unit in advance, and outputs a position command 107. In addition, the timing control unit 105 determines an operation start timing (time) 106 for starting the operation of each block according to the analysis data 103, the interpolation / acceleration / deceleration parameter 110, the position command 107, and the actual position 109. This is sent to the acceleration / deceleration unit 104. The interpolation / acceleration / deceleration unit 104 starts interpolation / acceleration / deceleration of the next operation at the timing (time) when the next operation is started in accordance with the operation start timing 106 and generates a position command 107.

  The servo control unit 108 performs servo control so as to follow the generated position command 107, drives an actuator (drive unit) (not shown), and operates a machine (not shown), thereby Execute the operation. The servo control units 108 are provided as many as the number of axes provided in the machine, and the actual position (position detection value) 109 of each axis is detected by a position detector (not shown), and feedback control performed in the servo control unit 108 is performed. And is sent to the timing control unit 105.

  Next, the operation of the timing control unit 105 will be described with reference to FIG. FIG. 2 is a flowchart for explaining the operation of the timing control unit 105. FIG. 3 is a waveform diagram showing a velocity waveform when the start timing of the next movement is controlled by the procedure of the flowchart of FIG. FIG. 4 is an XY graph showing the locus in that case. Here, the operation of FIG. 18 described above will be described as an example. Assume that the numerical controller 100 is currently executing the block N1 in FIG. In FIG. 2, the timing control unit 105 first calculates the completion time t1 of the current block N1 using the analysis data 103 and the parameter 110 in step ST11. That is, in FIG. 3, the analysis data 103 (moving distance, moving direction, moving speed) of the current block and parameter 110 (acceleration / deceleration pattern type (shape) such as triangular wave, trapezoid, S-shape, acceleration / deceleration time constant, acceleration, The velocity waveform Vx (t) is determined using a known method according to the maximum velocity, the interpolation mode, and the like.

  For example, in the case of trapezoidal acceleration / deceleration, a moving average filter with a predetermined acceleration / deceleration time constant is applied to a stepped command speed waveform that keeps the speed constant at the command speed for the time divided by the command speed. Is determined by At this time, if the time obtained by dividing the travel distance by the command speed is shorter than the acceleration / deceleration time constant, the triangular wave speed waveform is determined by matching the acceleration / deceleration time constant to the time obtained by dividing the travel distance by the command speed. The Similarly, in the case of S-curve acceleration / deceleration, it is determined by applying a two-stage moving average filter to the above-described stepped command speed waveform. In any case, when the maximum allowable speed of each axis is exceeded, the command speed is limited so that the absolute value of the speed of each axis is not more than the maximum speed of each axis.

  When the acceleration / deceleration pattern is determined, the movement completion time is also uniquely determined. For example, in the case of trapezoidal acceleration / deceleration, the sum of the acceleration / deceleration time constant and the time obtained by dividing the movement distance by the command speed is the movement time. The movement completion time t1 is a time obtained by adding the movement time to the movement start time. Similarly, in the case of S-curve acceleration / deceleration, the sum of the acceleration / deceleration time constant of each stage and the time obtained by dividing the movement distance by the command speed is the movement time. In general, assuming that an arbitrary velocity waveform Vx (t) is given, an analysis is made of a value where the velocity Vx (t) is 0 or the absolute value of the velocity is equal to or less than a predetermined minute velocity reference value after the movement start time. It may be obtained manually or numerically, and this may be set as the movement completion time t1.

Next, in step ST12, in the next block (N2), an allowable error from the start of movement of the block (maximum moving distance that can be moved in advance of the next movement = starting point allowable error = allowable moving distance) is L2max. A time Δt2 until the travel is obtained (predicted). In order to obtain Δt2, first, the velocity waveform Vy (t) in the block N2 is determined in the same manner as the method for obtaining the velocity waveform of the block N1 described above. Further, a time Δt2 until the distance (integrated value of Vy (t)) from the movement start time t2 of the block N2 coincides with L2max is obtained. For example, if the trapezoidal acceleration / deceleration is advanced by L2max during acceleration, if the acceleration of the trapezoidal acceleration / deceleration (= command speed / acceleration / deceleration time constant) is A, the acceleration speed is Vy (t) = A × ( t-t1)
Therefore, when it is integrated, Y (t) = (1/2) × A × (t−t1) × (t−t1)
Get. Accordingly, the condition that the integrated value of the velocity waveform matches the allowable error L2max is as follows. L2max = (1/2) × A × Δt2 × Δt2
That is, Δt2 that satisfies the above equation may be obtained.
Δt2 = √ (2 × L2max / A)
Similarly, in the case of other velocity waveforms, the time at which the integrated value of the velocity waveform matches the allowable error L2max may be solved analytically or numerically. That is, assuming that a function obtained by integrating Vy (t) is Y (t), a time t at which the position Y (t) matches L2max is obtained by analytical or numerical calculation.

  Next, in step ST13, the movement start time t2 of the next block (N2) is calculated using the results of steps ST11 and ST12. The start time t2 is a time obtained by subtracting the above-described Δt2 from the current movement completion time t1. This means that the next block starts to move in advance without waiting for the completion of the movement of the current block, and the movement of the next block has advanced by an allowable error L2max when the movement of the current block is completed. .

  Further, in step ST14, the remaining distance to the target position of the current block after time t2 obtained in step ST13 is an allowable error (maximum remaining distance of current movement = end point allowable error = allowable remaining distance) L1max. If it is below, the movement of the next block (N1) is started. Here, the remaining distance is a distance between the position command 107 or the actual position 109 and the target position (end point). That is, the movement of the next block is started only when both of the following two conditions are satisfied.

i) The remaining distance of the current movement is less than the allowable error ii) The distance that the next movement moves before waiting for the completion of the current movement is less than the allowable error, or in other words,
-Time when the remaining distance of the current movement becomes an allowable error (t1b)
The time (t2) when the next movement starts because the next movement moves ahead by an allowable error when the current movement is completed
It can be said that the later time is selected.

  FIG. 3 shows a velocity waveform when the start timing of the next movement is controlled by the procedure from step ST11 to step ST14. In the example of FIG. 3, since the time at t2 is later at t1b and t2, the condition of the above ii) dominates the start timing of the next movement. Here, when viewing the trajectory of FIG. 4, it is certain that the trajectory is in contact with N2 (the trajectory is on the path commanded to the program (in this case, a straight line)) that the end point of the current movement N1 commanded to the program ( = Start point of the next movement N2 = point P) is a point separated by a distance L2max in the movement direction of N2. Further, the distance between the point where the locus is away from N1 and the point P is L1max or less. That is, by starting the movement of the next block (N2) so that both the conditions i) and ii) are satisfied in step ST14, the trajectory error near the joint (intersection) P between N1 and N2 becomes N1. It can be seen that both the direction and the N2 direction are controlled to be within an allowable error.

  FIG. 22 shows a velocity waveform according to the conventional method (a method of starting the next operation when the remaining distance of the current operation is equal to or smaller than an allowable error), and FIG. 24 shows a locus thereof. In the conventional method, after the next movement is started (time t2) and until the current movement is completed (time t1), the movement is performed by the shaded area (L2) of Vy in the figure. The movement distance L2 depends on the speed waveform of the next movement. For example, when the speed of the next movement is high as shown in FIG. 23, L2 increases. That is, in the trajectory shown in FIG. 24, the distance from the point where the trajectory touches N2 and the start point of N2 cannot be kept constant, and the speed waveform changes as the command speed, travel distance, and travel direction change. To do. This means that the next command given to the program may cause insufficient accuracy of the trajectory near the start point of the next command, variation, or conversely, the cycle time may become longer due to excessive accuracy. was there.

  On the other hand, according to the present embodiment, in consideration of the next movement, the accuracy in the next movement can be limited to an allowable error or less, and the type of the next instruction (speed, movement) Regardless of distance, direction of movement, etc., the accuracy can be maintained within a necessary range, and the cycle time does not become long in an attempt to obtain an excessive accuracy. Since the cycle time can be shortened, there is an effect that energy consumption per workpiece can be reduced.

  Also, during trial operation before mass production, if the program is commanded in the order of N1, N2, it is normally moved from N1 to N2 (forward operation), but in some cases the same route is reversed. There may be a case where the presence / absence of mechanical interference and the positioning accuracy are checked while performing a return operation (ie, returning from N2 to N1) (operation in the reverse direction). In such a case, with the conventional technique, the trajectory is not the same between the forward motion and the backward motion, so that the confirmation work becomes inaccurate, an error occurs in the confirmation judgment, or the beginning of the program There is a problem that it takes time to go back to the head and re-check the operation in the forward direction from the head.

  According to the present embodiment, the trajectory error in the vicinity of the joint (intersection) P is controlled within a predetermined accuracy range in both the return direction (N1 direction) and the forward direction (N2 direction) as viewed from P. Therefore, the trajectory of the forward motion and the backward motion are almost the same (both are within the specified accuracy range), and the confirmation work can be performed stably and accurately regardless of the motion direction, without having to return to the top of the program one by one. There is an advantage that the presence / absence of machine interference and accuracy can be confirmed in a short time.

  In step ST14, it is determined whether or not the remaining distance to the target position of the current block is equal to or smaller than the allowable error L1max. However, the remaining distance may be determined from the difference between the position command 107 and the target position.

  Further, the above-described allowable errors L1max and L2max may be specified by a program for each block, for example, may be commanded as E1.0 (allowable error = 1.0 mm) at the address E, and the axis Each parameter may be determined in advance and selected according to the moving direction of each block. Alternatively, when a plurality of axes move with one moving block, the smallest value among the parameters corresponding to the moving axis may be used.

Embodiment 2. FIG.
In the first embodiment, the timing for starting the next block is determined in consideration of the accuracy of both the current block and the next block. In the present embodiment, a method for further shortening the cycle time will be described while considering both the accuracy in the same manner.

  FIG. 5 is a flowchart for explaining the operation in the present embodiment. In FIG. 5, the operation of step ST21 is the same as the operation of step ST11 of FIG. 2, and the operation of step ST22 is the same as the operation of step ST12 of FIG. 2, so description of these two steps will be omitted. Hereinafter, a description will be given using the example of FIG.

In step ST23, in the current block (N1), a time Δt1 until the movement is completed after the remaining distance to the target position (end point) becomes L1max is calculated (predicted). In order to obtain Δt1, first, in block N1, the velocity waveform Vx (t) and the movement completion time t1 are obtained by the method described in the first embodiment. Next, a time t = Δt2 at which the distance from the movement start completion time t1 of the block N1 (the integrated value of Vx (t) from time t to t1) matches L1max is obtained. For example, when trapezoidal acceleration / deceleration is performed by L1max during deceleration, if the acceleration of trapezoidal acceleration / deceleration (= speed / acceleration / deceleration time constant) is A, the speed during deceleration is
Vx (t) = A * (t1-t)
Therefore, when it is integrated, X (t) = (1/2) × A × (t1−t) × (t1−t)
Get. Accordingly, the condition that the integrated value of the velocity waveform matches the allowable error L1max is as follows. L1max = (1/2) × A × Δt1 × Δt1
That is, Δt1 that satisfies the above equation may be obtained.
Δt1 = √ (2 × L1max / A)
Similarly, in the case of other velocity waveforms, the time at which the X-axis position X (t), which is the integrated value of the velocity waveform Vx (t), coincides with the allowable error L1max may be solved analytically or numerically.

Next, in step ST24, the start time t2 of the next block (N2) is the time Δt2 at which the next block obtained in step ST22 starts moving from the completion time t1 of the current block (N1) and the current block (N1). The time is calculated as a time obtained by subtracting the sum of the time Δt1 that the block considers to be moved early. That is,
t2 = t1−Δt1−Δt2

  Further, in step ST25, the movement of the next block is started at time t2. FIG. 6 shows the velocity waveform and FIG. 7 shows the trajectory when control is performed according to this procedure. In the example of FIG. 6, the next movement is started at t2, which is a time earlier by Δt1 and Δt2 than the completion time t1 of the original current block. Further, at a time point t2a advanced by Δt2 from t2, the distance advanced in the Y-axis direction matches L2max and the remaining distance in the X-axis direction matches L1max. When this is seen in the locus of FIG. 7, the locus is controlled so as to pass through a point Q that is returned by L1max in the N1 direction and advanced by L2max in the N2 direction with respect to the end point P of N1 commanded to the program. I understand. That is, it can be seen that the locus error near the joint (intersection) between N1 and N2 is controlled so that both the N1 direction and the N2 direction coincide with the respective allowable errors at one point (point Q) near the intersection.

  According to the present embodiment, the accuracy of the current movement and the next movement can be limited to an allowable error or less while the start of the next movement is further advanced as compared with the first embodiment. In addition to the effect of 1, the cycle time can be further shortened. In addition, since control is performed so that the point (point Q) determined by the specified tolerance is passed, the trajectory is completely the same by passing this point Q in both forward and reverse movements, and during trial operation This confirmation work can be performed more accurately and in a short time.

Embodiment 3 FIG.
In the first embodiment, the timing for starting the next block is determined in consideration of the accuracy of both the current block and the next block. However, when the accuracy of the next block is important, it is also possible to simplify the processing by focusing on only that and performing control. In this embodiment, a method for that purpose will be described.

  FIG. 8 is a flowchart for explaining the operation in the present embodiment. In FIG. 8, step ST31 is the same as step ST11, step ST32 is the same as step ST12, and step ST33 is the same as step ST13. Therefore, the description of these three steps is omitted. Hereinafter, a description will be given using the example of FIG.

In step ST34, if it is after time t2 calculated | required by step ST33, the movement of the following block (N1) will be started. That is, the next movement is started when only the following one condition is satisfied.
ii) The distance that the next movement moves ahead without waiting for the completion of the current movement is less than the allowable error

  FIG. 9 shows the velocity waveform and FIG. 10 shows the locus when this procedure is followed. As shown in FIG. 9, the start timing of the next operation (N2) is determined only from the distance that the next operation moves in advance without considering the remaining distance of the current operation. Therefore, as shown in FIG. 10, the distance in the N2 direction with respect to the point P is limited to an allowable error L2max or less, but the distance in the N1 direction is not limited.

  However, the acceleration / deceleration filter and servo system characteristics of each axis gradually decrease with time, such as first-order lag and second-order lag, or drop from the peak to almost zero from the rise time to the peak. If the movement speed is the same, if the trajectory is longer, the point where the trajectory is in contact with the next movement than the distance between the point where the trajectory is away from the current movement and the point P The distance from the point P becomes longer. In such a case, if the error in the next movement direction is limited, the error in the current movement direction is naturally limited to that or less, and this is sufficient for practical use. By performing such control, processing can be performed without using the data such as the position command 107 or the actual position 109 in FIG. 1, so that the processing is simplified and can be realized with a smaller amount of communication and calculation, and the cost of the controller Can be expected.

Embodiment 4 FIG.
In the first to third embodiments, the distance that the next movement (N2) advances in advance from the head is limited to a certain value or less before the current movement (N1) is completed. However, in the case where the next operation (N3) of the next movement is performed and the accuracy in the operation (N3) is strongly required, the point where the trajectory touches the next movement (N2) and the end point of N2 It may be preferable to manage the distance. This embodiment will describe the method.

  The simplest example will be described based on the example of the third embodiment. However, it is assumed that the program consists of three blocks N1 to N3 as shown in FIG. In the block N3, the Z-axis position is -50. It is a command to move to.

This will be described with reference to FIG. In the third embodiment, L2max is a value obtained by subtracting the allowable error L2max ′ from the length of the movement (N2).
L2max = D2−L2max ′
Here, D2 represents the moving distance of the block N2, and L2max ′ represents the minimum value (minimum remaining distance) of the remaining distance of N2, that is, the point where the locus is in contact with the command path (N2) commanded to the program in the movement of N2. It corresponds to the distance to R and its end point S.

  When the above L2max is applied to the third embodiment, the velocity waveform is as shown in FIG. 13, and at the time t1 when the current movement (N1) is completed, the next distance is set so that the remaining distance of the next movement matches L2max ′. Starts moving (N2). As a result, as shown in FIG. 12, the locus coincides with the command route at a point R returned by the distance L2max ′ designated from the end point of N2.

  According to the present embodiment, for example, when N2 is followed by an operation that requires more accurate positioning and accuracy, such as a cutting feed operation, a tool change operation, and a measurement operation, when viewed from N2, By completely eliminating the influence of the trajectory error due to the movement at the time point before the end point of N2 by the designated distance, the operation performed after N2 can be performed stably and accurately. As a basic procedure, there is no difference between specifying the distance from the start point of movement and specifying the distance from the end point, but from the viewpoint of the user, the distance from the end point is set to a certain parameter ( If it is specified by L2max ′), it is not necessary for the user to specify for each distance of movement, and the effect of improved usability can be obtained.

  As a special example, by setting L2max ′ to 0, as shown in FIG. 14, it is possible to perform control so that the completion timings of a plurality of operations coincide. In this case, if there is an order relationship that the next N3 operation is possible only after the operations of both N1 and N2 are completed, if the operation N2 is started as shown in FIG. At the start of the operation, the waiting time from the point of completion of N1 is zero. Further, even if the timing of N2 is further advanced, the cycle time is not shortened any more, and conversely, the completion of N1 is later than N2, and the order originally commanded to the program is changed. It will collapse extremely and may cause unnecessary mechanical interference. In that sense, as shown in FIG. 14, the method of determining the start timing of N2 so that the completion timings of a plurality of operations coincide with each other can be said to be a timing that is necessary and sufficient to shorten the cycle time to the maximum. .

  The method described in the present embodiment has been described based on the method described in the third embodiment. However, the method can be similarly applied to the methods described in the first and second embodiments.

Embodiment 5 FIG.
In the first to fourth embodiments, for ease of explanation, an example has been described in which only one axis movement command is issued to each of the blocks N1 and N2. On the other hand, a method for dealing with a case where a movement command for a plurality of axes is instructed in each block and movement of each axis is performed simultaneously will be described.

  As a most typical example, a case will be described in which the first embodiment is used as a basis and is extended to a parallel operation of a plurality of axes. For example, assume that a program as shown in FIG. 15 is given. Here, X, Y, Z, and C indicate axis names, respectively, and the subsequent numbers indicate the coordinate values of the target position of each axis.

  FIG. 16 is a flowchart showing an operation procedure in the present embodiment. In FIG. 16, first, in step ST51, as in step ST11, the completion time t1 of the movement of the X axis is obtained in the current block N1, and similarly, the completion time t1 'of the movement of the Z axis is obtained. Of the two, select the slower one and set it as T1. In this example, T1 = t1 '.

  Next, in step ST52, in the next block N2, as in step ST12, Δt2 is obtained by the time from the start of movement of the Y axis to the advance of L2max, and similarly, from the start of movement of the C axis to the advance of L2max. Δt2 ′ is obtained by time. The smaller of them is selected as ΔT2. In this example, ΔT2 = Δt2 ′.

In step ST53, the start time t2 of the next block is obtained. That is,
t2 = T1-ΔT2

  In step ST54, if it is after time t2 obtained in step ST53 and the remaining distances in the X-axis and Z-axis of the current block (N1) are each equal to or less than the allowable error (L1max), the next block (N2) Start moving.

  That is, the above procedure starts the next movement when the remaining distance of all the axes in the current block is less than the allowable error and the preceding moving distance of all the axes in the next block is less than the allowable error. .

FIG. 17 shows a velocity waveform when this procedure is applied. That is, the timing for starting the next operation N2 corresponds to selecting the latest time among the following four times.
T1b: time point when the remaining distance on the X axis of the current block is less than or equal to the allowable error (L1max) t1b ′: time point when the remaining distance on the Z axis of the current block is less than or equal to the allowable error (L1max) t2: current time When the movement of all axes of the block is completed,
When the distance that the Y axis of the next block advances is less than the tolerance (L2max) t2 ′: When the movement of all the axes of the current block is completed,
When the distance that the C axis of the next block advances is less than the tolerance (L2max)

  According to this embodiment, even if movement of a plurality of axes is commanded in each block, errors of all axes can be managed, and cycle time can be shortened while maintaining accuracy. Become.

  It should be noted that the method described in the present embodiment can be similarly applied when a plurality of operations are executed in parallel in a multi-system machine tool or the like in which a plurality of tools move simultaneously.

  In the above description, each axis operates independently (the operation completion time of each axis varies depending on the axis). However, the present invention can be similarly applied to a case where all axes operate synchronously (interpolation operation). . In this case, the times t1 and t1 'are the same time.

  The numerical control device of the present invention is suitable for being applied to a numerical control device that controls the motion of a machine tool, robot, industrial machine, etc., and while maintaining a predetermined accuracy, particularly in a positioning movement operation to a target position, It is optimal when you want to shorten the cycle time.

It is a whole lineblock diagram of an embodiment of a numerical control device of the present invention. It is a figure of the flowchart which shows the operation | movement of Embodiment 1 of this invention. It is a wave form diagram which shows the velocity waveform of Embodiment 1 of this invention. It is a figure which shows the XY graph which shows the locus | trajectory of Embodiment 1 of this invention. It is a figure of the flowchart which shows the operation | movement of Embodiment 2 of this invention. It is a wave form diagram which shows the speed waveform of Embodiment 2 of this invention. It is a figure which shows the XY graph which shows the locus | trajectory of Embodiment 2 of this invention. It is a figure of the flowchart which shows the operation | movement of Embodiment 3 of this invention. It is a wave form diagram which shows the speed waveform of Embodiment 3 of this invention. It is a figure which shows the XY graph which shows the locus | trajectory of Embodiment 3 of this invention. It is a figure which shows an example of NC program of Embodiment 4 of this invention. It is a figure which shows the XY graph which shows the locus | trajectory of Embodiment 4 of this invention. It is a wave form diagram which shows the velocity waveform of Embodiment 4 of this invention. It is a wave form diagram which shows the velocity waveform of Embodiment 4 of this invention. It is a figure which shows an example of NC program of Embodiment 5 of this invention. It is a figure of the flowchart which shows the operation | movement of Embodiment 5 of this invention. It is a wave form diagram which shows the velocity waveform of Embodiment 5 of this invention. It is a figure which shows an example of NC program. FIG. 19 is an XY graph diagram illustrating a command path of the NC program example of FIG. 18. It is a wave form diagram which shows the speed waveform of a prior art. It is a figure which shows the XY graph which shows the locus | trajectory of a prior art. It is a wave form diagram which shows the speed waveform of a prior art. It is a wave form diagram which shows the other speed waveform of a prior art. It is a figure which shows the XY graph which shows the locus | trajectory of a prior art.

Explanation of symbols

100 Numerical control device 101 NC program (program)
102 Analysis processing unit 103 Analysis data 104 Interpolation / acceleration / deceleration unit 105 Timing control unit 106 Operation start timing 107 Position command 108 Servo control unit 109 Actual position 110 Interpolation / acceleration / deceleration parameter (parameter)

Claims (1)

In a numerical control device that controls the operation of a moving body by sequentially executing a plurality of operation commands instructed by a program,
An analysis processing unit that analyzes operation commands instructed by the program and generates analysis data;
Based on the analysis data and pre-stored interpolation / acceleration / deceleration parameters, a timing control unit for obtaining an operation start timing of the next operation;
An interpolation / acceleration / deceleration unit that generates a position command for performing interpolation / acceleration according to the analysis data, the interpolation / acceleration / deceleration parameters, and the operation start timing;
A servo control unit that servo-controls the drive unit so as to follow the position command,
The timing controller is
Calculating a time when the remaining distance to the target position of the current operation matches the end point tolerances, the distance moved by the next operation, remaining distance until said target position of the current operation matches the end point tolerance The numerical control device characterized in that the operation start timing is obtained so as to coincide with a start point allowable error at a time.

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