control device

Abstract

Provided is a control device for a machine tool having three or more rotary axes that prevents interference between a workpiece and a tool and prevents variations in machining results even when an interrupt is made to a rotary axis during automatic operation. The control device controls a machine tool, the machine tool having three or more tool attitude control axes that control the attitude of the tool, the attitude of the tool including a tool axis direction, and the control device comprises: an interrupt control unit that interrupts an interrupt move command from the machine tool into each axis move command including a move command for at least any of the tool attitude control axes and generates a post-interrupt each axis move command; and a tool axis direction maintaining move generator that generates a tool axis direction maintaining move based on the post-interrupt each axis move command in order to maintain the tool axis direction with respect to the workpiece.

Description

[Technical Field]

[0001] The present disclosure relates to a control device. [Background technology]

[0002] Conventionally, manual handle interruption has been known as a means for a user to manually intervene in the automatic operation of a machine tool. The manual handle interruption shifts the movement path of the tool center point during automatic operation by the amount of interruption. Regarding such shifting of the movement path during automatic operation, a control device is known that can shift the movement path during automatic operation relative to any coordinate system on the machine configuration by applying an external pulse to a kinematic transformation (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7000634 Summary of the Invention [Problem to be solved by the invention]

[0004] When a manual handle interrupt is performed on a rotary axis during automatic operation, the axial direction of the tool relative to the workpiece will be different from the axial direction of the tool if no interruption is performed. Therefore, manual handle interruption may cause interference between the workpiece and the side of the tool. Also, when machining using the side of the tool, manual handle interruption may change the machining results.

[0005] Therefore, there is a demand for a control device that can avoid interference between the workpiece and the tool and prevent fluctuations in the machining results, even when an interrupt is made to a rotary axis during automatic operation, particularly in machine tools with three or more rotary axes. [Means for solving the problem]

[0006] One aspect of the present disclosure is a control device for controlling a machine tool, the machine tool having three or more tool attitude control axes that control the attitude of the tool relative to a workpiece, the attitude of the tool including a tool axis direction, the control device comprising: an interrupt control unit that interrupts an interrupt move command from the machine tool into each axis move command including a move command for at least any of the tool attitude control axes, and generates each axis move command after the interrupt; and a tool axis direction maintaining move generation unit that generates a tool axis direction maintaining move based on the each axis move command after the interrupt, in order to maintain the tool axis direction relative to the workpiece. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a functional block diagram of the control system according to the present embodiment. [Figure 2] 1 is a diagram showing an overview of a machine tool according to an embodiment of the present invention; [Figure 3] FIG. 2 is a functional block diagram of a CPU in the control device according to the present embodiment. [Figure 4] FIG. 10 is a diagram illustrating a manual handle interruption for a rotary axis of a machine tool. [Figure 5] FIG. 10 is a diagram illustrating a manual handle interruption for a rotary axis of a machine tool. [Figure 5A] FIG. 10 is a diagram illustrating an example of a tool phase angle. [Figure 6] FIG. 10 is a diagram illustrating a first example of processing by the control device. [Figure 7] FIG. 10 is a diagram illustrating a second example of processing by the control device. [Figure 8] FIG. 10 is a diagram illustrating a third example of processing by the control device. [Figure 9] FIG. 10 is a diagram illustrating a fourth example of processing by the control device. [Figure 10] FIG. 10 is a diagram illustrating a fifth example of processing by the control device. [Figure 11] FIG. 10 is a diagram illustrating a specific example of processing when a manual handle interruption is performed. [Figure 12] 10A and 10B are diagrams illustrating a first application example in which a process for maintaining a tool axis direction during automatic operation is applied. [Figure 13] 5A to 5C are diagrams schematically showing the operation of the machine tool in the first application example. [Figure 14] 10A and 10B are diagrams illustrating a second application example in which a process for maintaining the tool axis direction during automatic operation is applied. [Figure 15] 15 is a diagram showing a model of the A axis, B axis, and C axis in FIG. 14. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] A control system 1 according to an embodiment of the present disclosure will be described below with reference to the drawings. Fig. 1 is a functional block diagram of the control system 1 according to the present embodiment. The control system 1 includes a control device 10 and a machine tool 20.

[0009] The control device 10 is communicatively connected to the machine tool 20 and controls the machine tool 20. The control device 10 may be communicatively connected not only to the machine tool 20 but also to a robot (not shown) and control both the machine tool 20 and the robot. The control device 10 may also function as a numerical control device that controls the machine tool 20, or as a robot control device that controls the robot.

[0010] The control device 10 mainly comprises a CPU 11, a ROM 12, a RAM 13, a CMOS memory 14, interfaces 15, 18, and 19, a PMC (programmable machine controller) 16, an I / O unit 17, and axis control circuits 31, 32, 33, 34, 35, and 36.

[0011] The CPU 11 is a processor that performs overall control of the control device 10. The CPU 11 reads a system program stored in the ROM 12 via the bus 60, and controls the entire control device 10 in accordance with the system program.

[0012] The RAM 13 stores temporary calculation data, display data, and various data input by the operator via the display / MDI unit 70 .

[0013] The CMOS memory 14 is configured as a non-volatile memory that receives power from a battery (not shown) and retains its stored state even when the power to the control device 10 is turned off. The CMOS memory 14 stores machining programs loaded via the interface 15, machining programs input via the display / MDI unit 70, etc.

[0014] The ROM 12 is pre-written with various system programs for carrying out processes in an edit mode required for creating and editing a machining program and processes for automatic operation.

[0015] Various machining programs are input via the interface 15 and the display / MDI unit 70 and stored in the CMOS memory 14.

[0016] The interface 15 enables connection between the control device 10 and an external device (FCA) 72 such as an adapter. Machining programs, various parameters, etc. are read from the external device 72. In addition, machining programs edited within the control device 10 can be stored in external storage means via the external device 72.

[0017] PMC (Programmable Machine Controller) 16 uses a sequence program stored in control device 10 to output signals to auxiliary devices (for example, actuators such as a robot hand for tool replacement) of machine tool 20 via I / O unit 17, thereby controlling the auxiliary devices. PMC 16 also receives signals from various switches on an operation panel 71 provided on the main body of machine tool 20, performs the necessary signal processing, and then outputs the signals to CPU 11.

[0018] The display / MDI unit 70 is a manual data input device equipped with a display, keyboard, etc. The interface 18 receives commands and data from the keyboard of the display / MDI unit 70 and outputs them to the CPU 11. The interface 19 is connected to the operation panel 71.

[0019] The operation panel 71 is equipped with buttons, switches, etc., including mechanical buttons and switches. When a mechanical button or switch is pressed, the buttons and switches output a button signal or switch signal to the PMC 16 via the interface 19.

[0020] The operation panel 71 further includes a manual handle 711. The manual handle 711 moves one or more axes by manual operation. The manual handle 711 includes, for example, a handle unit, a pulse generating unit, and a driver. The handle unit is configured as a mechanical manual handle and is operated by the operator.

[0021] For example, when the handle is rotated in the positive or negative direction, the pulse generating unit outputs a pulse signal in accordance with the rotation. The pulse signal is a two-phase pulse for determining the direction of rotation, and is transmitted to CPU 11 via bus 60. CPU 11 then transmits movement commands for the axes of machine tool 20 to servo amplifiers 41, 42, 43, 44, 45, and 46 based on the pulse signal.

[0022] The axis control circuits 31, 32, 33, 34, 35, and 36 for the respective axes receive movement command amounts for the respective axes from the CPU 11 and output the commands for the respective axes to servo amplifiers 41, 42, 43, 44, 45, and 46. The servo amplifiers 41, 42, 43, 44, 45, and 46 receive the commands for the respective axes and drive servo motors 51, 52, 53, 54, 55, and 56 for the respective axes.

[0023] The servo motors 51, 52, 53, 54, 55, and 56 for the respective axes each have a built-in detector, such as a rotary encoder, that detects the position, speed, etc. The servo motors 51, 52, 53, 54, 55, and 56 feed back position and speed feedback signals from the detector to the axis control circuits 31, 32, 33, 34, 35, and 36, thereby performing feedback control of the position and speed.

[0024] It should be noted that feedback of position and velocity is omitted in Fig. 1. The configuration of the control device 10 shown in Fig. 1 is an example, and the control device 10 is not limited to this, and a general-purpose numerical control device may also be used.

[0025] 2 is a diagram showing an overview of a machine tool 20 according to this embodiment. The machine tool 20 is equipped with three or more tool attitude control axes that control the attitude of the tool, and a machining feed axis that moves the tool relative to the workpiece. In other words, the machine tool 20 is a machine tool with three or more rotation axes (i.e., three or more degrees of freedom), and therefore has redundant degrees of freedom for a tool axis direction command that requires two degrees of freedom.

[0026] The machine tool 20 shown in Figure 2 is a six-axis machining center. The machine tool 20 has a bed 21, a pair of column units 22 provided on the bed 21, and a rail unit 23 that connects the upper ends of the column units 22 and extends laterally. A tool head 24 is attached to the rail unit 23. The machine tool 20 has three linear axes: an X-axis that is in the plane direction of the bed 21 and along the length of the rail unit 23, a Y-axis that is in the plane direction of the bed 21 and perpendicular to the length of the rail unit 23, and a Z-axis that is perpendicular to the plane direction of the bed 21. The tool head 24 is provided so as to be linearly movable along each of these three axes: the X-axis, the Y-axis, and the Z-axis.

[0027] A tool 25, which is a movable shaft member, is provided at the lower end of the tool head 24. Specifically, a first rotating unit 26 that rotates the tool 25 so as to swing around an A-axis along the X-axis direction, and a second rotating unit 27 that rotates the first rotating unit 26 around a C-axis along the Z-axis direction are provided at the lower end of the tool head 24. The A-axis and C-axis of the machine tool 20 are disposed on the tool 25 side and are rotation axes that determine the tool direction, which is the orientation of the tool 25 relative to the workpiece W, through rotation. A table 28 is disposed on the bed 21, on which the workpiece W to be machined is placed. The table 28 is rotatably provided by a third rotating unit 29 that is inclined with respect to the surface direction of the bed 21.

[0028] 3 is a functional block diagram of the CPU 11 in the control device 10 according to this embodiment. The CPU 11 realizes various functions by executing system programs and application programs stored in storage devices such as the ROM 12, RAM 13, and CMOS memory 14.

[0029] Furthermore, the CPU 11 includes a command analysis unit 101, an interpolation unit 102, a pulse generation unit 103, a servo control unit 104, a kinematic conversion unit 105, an interrupt control unit 106, a tool axis direction maintaining movement generation unit 107, a constraint condition calculation unit 108, a constraint condition interrupt control unit 109, a machine configuration tree holding unit 110, a position management unit 111, a singular point distance calculation unit 112, a machine lock pulse generation unit 113, and a constraint condition setting unit 114.

[0030] The command analysis unit 101 analyzes commands including a machining program for machining a workpiece and converts the commands into an executable format. The command analysis unit 101 outputs the analysis results converted into the executable format to the interpolation unit 102. Here, the machining program is a program for automatically operating the machine tool 20. The analysis results also include program coordinate values. The program coordinate values ​​indicate one or more command values ​​commanded in the program, and the program coordinate system indicates the coordinate system of one or more command values ​​commanded in the program.

[0031] Interpolation unit 102 performs interpolation processing on the analysis results obtained by command analysis unit 101, and generates movement commands for each axis of machine tool 20. Interpolation unit 102 outputs the generated movement commands to pulse generation unit 103.

[0032] Specifically, the interpolation unit 102 interpolates the program coordinate values ​​(i.e., the start point and end point in the program coordinate system) included in the analysis result, outputs them to the kinematic conversion unit 105, and accepts the motor coordinate values ​​(i.e., the start point and end point in the motor coordinate system) converted by the kinematic conversion unit 105. Then, the interpolation unit 102 calculates the difference between the start point and end point of the motor coordinate values, and outputs a movement command including the difference to the pulse generation unit 103.

[0033] The pulse generating unit 103 generates drive pulses for driving each axis of the machine tool 20 based on the movement command generated by the interpolating unit 102. The pulse generating unit 103 outputs the generated drive pulses to the servo control unit 104.

[0034] Servo control unit 104 rotates servo motors 51, 52, 53, 54, 55, and 56 for each axis in accordance with the drive pulses sent from pulse generation unit 103. Servo control unit 104 refers to the servo control unit for each axis of machine tool 20. Details of the operations from kinematic conversion unit 105 to constraint condition setting unit 114 will be described later.

[0035] Figures 4 and 5 are diagrams showing manual handle interruption to the rotary axis of machine tool 20. Figure 5A is a diagram showing an example of a tool phase angle. Note that Figures 4 and 5 show a model of machine tool 20, which differs in structure, shape, etc. from the actual machine tool 20. Similarly, Figures 11, 13, and 15 also show a model of machine tool 20, which differs in structure, shape, etc. from the actual machine tool 20.

[0036] As shown in Fig. 5A, the tool phase direction is a direction that indicates the attitude of the tool 25, and the reference tool phase direction is a reference tool phase direction. In the example of Fig. 5A, the reference tool phase direction and the tool phase direction are set on the surface of the workpiece W, and the tool phase angle (φ) is the angle formed between the reference tool phase direction and the tool phase direction. A specific example of a constraint condition, which will be described later, is the tool phase angle (φ). Note that even if the tool phase angle fluctuates, the tool axis direction does not fluctuate, and has a degree of freedom that is independent of the tool axis phase.

[0037] 4 and 5, when the control device 10 performs an interruption with the manual handle 711 with respect to the C axis as a rotation axis, the tool axis direction with respect to the workpiece W becomes different from when no interruption is performed. Therefore, there is a possibility that interference occurs between the workpiece W and the side surface of the tool 25. Furthermore, when machining using the side surface of the tool 25, there is a possibility that the machining results will change due to the interruption.

[0038] Specifically, in the example shown in Figure 4, when the control device 10 interrupts the C axis as a rotation axis using the manual handle 711, only the tip point of the tool 25 follows the interrupt, and interference occurs between the workpiece W and the side of the tool 25.

[0039] Therefore, as shown in the example of Fig. 5, when an interrupt is performed by manual handle 711 in machine tool 20, control device 10 according to this embodiment controls the tool axis direction to follow the interrupt and maintain the tool axis direction. Here, machine tool 20 has three or more rotation axes (i.e., tool attitude control axes). Machine tool 20 has redundant degrees of freedom, and since the required degrees of freedom in the tool axis direction are two, one degree of freedom is redundant.

[0040] The control device 10 adds the movement pulses of the rotation axes generated by the manual handle interrupt to each axis movement command to generate each axis movement command after the interrupt. Then, the control device 10 maintains the tool axis direction relative to the workpiece W by generating tool axis direction maintaining movements (a+δa', b+δb', c+δc) based on the post-interrupt movement command (a, b, c+δc) as shown in the following equation.

number

[0041] Next, examples of processing by the control device 10 will be described with reference to Figures 6 to 10. Figure 6 is a diagram showing a first example of processing by the control device 10. As described above, the machine tool 20 is equipped with three or more tool attitude control axes that control the attitude of the tool, and a machining feed axis that moves the tool relative to the workpiece.

[0042] The three or more tool attitude control axes are, for example, the A-axis, B-axis, and C-axis in Fig. 2 described above. The machining feed axes are, for example, the X-axis, Y-axis, and Z-axis in Fig. 2 described above. The attitude of the tool 25 includes the tool axis direction (for example, the C-axis direction in Fig. 2).

[0043] 6, the interrupt control unit 106 interrupts each axis movement command (a, b, c) with an interrupt movement command (+δc), and generates each axis movement command (a, b, c+δc) after the interruption. Here, each axis movement command includes a movement command for any of the tool attitude control axes (i.e., A-axis, B-axis, and C-axis).

[0044] The tool axis direction maintaining movement generating unit 107 generates tool axis direction maintaining movements (a+δa', b+δb', c+δc) based on the post-interrupt axis movement commands (a, b, c+δc) in order to maintain the tool axis direction relative to the workpiece W.

[0045] As a result, even when a manual handle interrupt command is input to the rotation axis, the control device 10 can avoid interference between the workpiece W and the tool 25 by maintaining the tool axis direction relative to the workpiece W, and in the case of machining using the tool side, can avoid fluctuations in the machining results due to interruption.

[0046] Fig. 7 is a diagram showing a second example of the processing of the control device 10. As shown in Fig. 7, the constraint condition interrupt control unit 109 interrupts the constraint condition (φ) with a constraint condition interrupt command (+δφ), and generates a post-interrupt tool attitude command ((i, j, k), φ+δφ).

[0047] The kinematic conversion unit 105 generates each axis movement command (a, b, c) based on the tool attitude command ((i, j, k), φ) which includes the tool axis direction (i, j, k) and a constraint condition (φ) that constrains one or more degrees of freedom independent of the tool axis direction.

[0048] In particular, the kinematic conversion unit 105 generates each axis movement command (a, b, c) based on the post-interrupt tool attitude command ((i, j, k), φ+δφ) in order to maintain the tool axis direction relative to the workpiece W. Thereafter, similar to Fig. 6, the tool axis direction maintenance movement generation unit 107 generates tool axis direction maintenance movements (a+δa', b+δb', c+δc).

[0049] In the first example shown in Fig. 6, the tool axis direction maintaining movement generating unit 107 generates a movement that maintains the tool axis direction relative to the workpiece W. On the other hand, the second example shown in Fig. 7 differs from the first example shown in Fig. 6 in that the kinematic conversion unit 105 generates each axis movement command that maintains the tool axis direction relative to the workpiece W.

[0050] Fig. 8 is a diagram showing a third example of the processing of the control device 10. As shown in Fig. 8, the constraint condition calculation unit 108 generates a constraint condition interrupt command (+δφ) based on the tool axis direction maintenance movement (a+δa', b+δb', c+δc).

[0051] The constraint condition interrupt control unit 109 (tool phase direction interrupt control unit 1091) interrupts the tool phase interrupt command (+δφ) into the tool attitude command ((i, j, k), φ) to generate a post-interrupt tool attitude command ((i, j, k), φ+δφ). Thereafter, the kinematic conversion unit 105, the interrupt control unit 106, and the tool axis direction maintenance movement generation unit 107 perform the same processing as in FIG. 7.

[0052] In the first example shown in Fig. 6, the tool axis direction maintaining move generator 107 generates a tool axis direction maintaining move for the workpiece W in response to an interrupt move command. In contrast to the first example shown in Fig. 6, the third example shown in Fig. 8 differs in that the kinematic conversion unit 105 generates each axis move command that maintains the tool axis direction for the workpiece W in response to an interrupt move command. As a result, in the third example, the tool axis direction maintaining move generator 107 does not need to perform processing except during an interrupt move command, and therefore the calculation load can be reduced compared to the first example.

[0053] Fig. 9 is a diagram showing a fourth example of processing by the control device 10. As shown in Fig. 9, the interpolation unit 102 generates a post-interrupt tool posture pulse based on a post-interrupt tool posture command ((i, j, k), φ+δφ). The kinematic conversion unit 105 generates axis movement pulses (a, b, c) as each axis movement command based on the post-interrupt tool posture pulse.

[0054] The interrupt control unit 106 inserts an interrupt movement pulse (+δc) into the axis movement pulses (a, b, c) as an interrupt command, and generates post-interrupt axis movement pulses (a, b, c+δc) as post-interrupt axis movement commands. The tool axis direction maintenance movement generation unit 107 generates tool axis direction maintenance pulses (a+δa', b+δb', c+δc) as tool axis direction maintenance movements based on the post-interrupt axis movement pulses (a, b, c+δc).

[0055] The pulse generating unit 103 generates drive pulses for driving the tool attitude control axes (e.g., A-axis, B-axis, and C-axis) based on the tool axis direction maintaining pulses (a+δa', b+δb', c+δc) and outputs them to, for example, axis control circuits 34, 35, and 36.

[0056] 10 is a diagram showing a fifth example of processing by control device 10. Machine configuration tree holding unit 110 generates a machine configuration tree that represents the machine configuration of machine tool 20 using a tree structure, and holds this machine configuration tree. Based on the machine configuration tree held by machine configuration tree holding unit 110, kinematic conversion unit 105 converts the post-interrupt tool attitude command ((i, j, k),φ+δφ) into each axis movement command (a, b, c).

[0057] The machine configuration tree storage unit 110 generates a tree structure that represents the machine configuration of the machine tool 20. Specifically, the machine configuration tree storage unit 110 arranges, for example, an origin and multiple nodes. At this stage, there is no connection between the origin and the multiple nodes, and names of the origin and the nodes have not been set.

[0058] Next, the machine configuration tree holding unit 110 sets the machine tool 20 as the origin, and sets the axis name (axis type) of each axis of the machine tool 20, the name of each tool, the name of each workpiece, the name of each origin, and the physical axis number (axis type) of each axis to each node.

[0059] Next, the machine configuration tree storage unit 110 sets a parent node (axis type) for each axis, a parent node for each tool, and a parent node for each workpiece. Finally, the machine configuration tree storage unit 110 sets a cross offset (axis type) for each axis, a cross offset for each tool, and a cross offset for each workpiece. As a result, the machine configuration tree storage unit 110 can generate a tree structure representing the machine configuration of the machine tool 20. The generation of a machine configuration tree is described in detail, for example, in Japanese Patent No. 7000634.

[0060] Next, the above processing will be explained in detail using mathematical expressions. First, the control device 10 issues commands to the rotation axes A, B, and C. At this time, the control device 10 automatically generates the tool axis directions (i, j, k) and the tool phase angle (φ). The generation of such tool axis directions (i, j, k) and tool phase angles (φ) is a known technique. The tool axis directions (i, j, k), the tool phase angle (φ), and the rotation axis angles (a, b, c) have a relationship represented by the following equation (1).

number

[0061] Next, an interrupt is generated by the manual handle 711. When an interrupt is generated by the manual handle 711, the control device 10 generates an interrupt pulse (δc).

[0062] Next, the tool axis direction maintenance movement generating unit 107 of the control device 10 outputs movement pulses (δa', δb') using the following equation (2).

number

number

[0063] Next, the constraint condition calculation unit 108 of the control device 10 calculates the change (δφ) in the tool phase direction (φ) based on the obtained rotation axis angle (a+δa', b+δb', c+δc) and the following equation (3).

number

[0064] Next, the control device 10 shifts the tool phase direction φ by +δφ, so that the tool axis direction in the subsequent automatic operation is maintained regardless of whether or not a manual handle interruption occurs.

[0065] Fig. 11 is a diagram showing a specific example of processing when a manual handle interruption is performed. In state (1) of Fig. 11, when the manual handle is used to interrupt the C-axis by 90°, the command coordinate system transitions from state (1) to state (2). At this time, the change amount (δφ) in the tool phase direction (φ) is calculated by the constraint condition calculation unit 108 as shown in state (3).

[0066] As a result of states (2) and (3), as shown in state (4), the control device 10 shifts the tool phase direction (φ) by (+δ), and can intrude 90° into the C-axis while maintaining the tool axis direction relative to the workpiece W.

[0067] In addition, in state (4), the tool axis direction relative to the workpiece W is the same in state (1) and state (4), i.e., is maintained. Furthermore, the coordinate system in state (4) is rotated relative to the table 28, just like in state (2).

[0068] Fig. 12 is a diagram showing a first application example in which a process for maintaining the tool axis direction during automatic operation is applied. Fig. 13 is a diagram showing a schematic diagram of the operation of machine tool 20 in the first application example. In state (1-1) of Fig. 13, when a 90° interrupt occurs in the C-axis by the manual handle, an interrupt movement pulse (+δc) is generated.

[0069] The interrupt control unit 106 inserts an interrupt movement pulse (+δc) into the axis movement pulses (a, b, c) as an interrupt command, and generates post-interrupt movement pulses for each axis (a, b, c+δc) as post-interrupt movement commands for each axis. This causes the tool center point to follow the interrupt (state (1-2) in Figure 13).

[0070] In state (1-2) of Fig. 13, the tool axis direction maintaining movement generating unit 107 generates tool axis direction maintaining pulses (a+δa', b+δb', c+δc) for the axes other than the interrupted axis, i.e., the A axis and B axis, thereby maintaining the tool axis direction relative to the workpiece (state 1-3 of Fig. 13).

[0071] In state (1-3) of Figure 13, the constraint condition calculation unit 108 calculates the tool phase direction based on the tool axis direction maintenance pulse, and generates a tool phase interrupt pulse (+δφ) as the difference between when there is an interrupt and when there is no interrupt.

[0072] In state (1-4) of FIG. 13, the machine configuration tree holding unit 110 stores the tool phase information in the node indicating the tool in the machine configuration tree. The constraint condition interrupt control unit 109 corrects the tool phase direction by shifting the tool phase information in the machine configuration tree held by the machine configuration tree holding unit 110 based on the tool phase interrupt pulse (+δφ). The shift in the tool movement direction is described in detail in, for example, Japanese Patent No. 7000634. As a result, subsequent automatic operation is executed with the tool phase direction shifted compared to the automatic operation before the interrupt (1-5 of FIG. 13).

[0073] The tool phase direction (φ+δφ) after the interruption is calculated so that the following equation (4) is satisfied with the rotation axis angles (a+δa', b+δb', c+δc) after the interruption.

number

[0074] In the state (1-5) of Fig. 13, the tool axis direction as seen from the workpiece coordinate system of the original automatic operation (i.e., the X direction on the table 28) coincides with the tool axis direction as seen from the workpiece coordinate system of the automatic operation after the interruption. By this processing, the subsequent automatic operation is performed while maintaining the tool axis direction of the original automatic operation, as in the state (1-5) of Fig. 13.

[0075] Fig. 14 is a diagram showing a second application example in which a process for maintaining the tool axis direction in automatic operation is applied. Fig. 15 is a diagram showing a model of the A-axis, B-axis, and C-axis in Fig. 14. The operation of the control device 10 will be described using the following machining program as an example. N01 G00 Aa Bb Cc N02 Ii Jj Kk First, in block N01, the control device 10 issues commands for the A-axis, B-axis, and C-axis. Next, in block N02, the control device 10 issues a tool axis direction command (i, j, k). At this time, the control device 10 generates a tool attitude command ((i, j, k), b) by adding the coordinate value b of the B-axis, which is the command end point in block N01, to the tool axis direction command as a constraint condition.

[0076] 9 and 12. The kinematic conversion unit 105 generates axis movement pulses (a, b, c) as axis movement commands based on the post-interrupt tool attitude pulses including the tool axis direction (i, j, k) and the B-axis angle (b). The position management unit 111 outputs the current coordinate values ​​of each rotation axis to the singularity distance calculation unit 112 based on the axis movement pulses (a, b, c) output from the kinematic conversion unit 105.

[0077] The singularity distance calculation unit 112 receives the rotation axis directions, which are the rotation angles of each rotation axis after interpolation, and the tool directions from the interpolation unit 102, and calculates the singularity distance from the rotation axis directions and the tool directions. The singularity distance is found by taking the cross product of the rotation axis directions and the tool directions. The calculation of the singularity distance is described in detail in, for example, Japanese Patent No. 6985563.

[0078] When the singularity distance calculation unit 112 detects that the C-axis has moved near the singularity, it notifies the machine lock pulse generation unit 113. When the machine lock pulse generation unit 113 is notified that the C-axis has moved near the singularity, it generates an interrupt movement pulse (-c) that cancels the movement of the C-axis.

[0079] At this time, the tool direction and the direction of the rotation axis coincide, that is, the singularity distance is small, as shown in state (2-1) in Figure 15. In state (2-1), the A-axis and C-axis are used for contouring control, and the B-axis is fixed.

[0080] The interrupt control unit 106 inserts an interrupt movement pulse (-c) into the axis movement pulses (a, b, c) as an interrupt command, and generates post-interrupt axis movement pulses (a, b, 0) as post-interrupt axis movement commands. The tool axis direction maintenance movement generation unit 107 generates a tool axis direction maintenance pulse (a+δa, b+δb, 0) as a tool axis direction maintenance movement based on the post-interrupt axis movement pulses (a, b, 0).

[0081] At this time, as shown in state (2-2) in Figure 15, the C-axis stops due to machine lock, and the tool axis direction maintenance movement generating unit 107 generates a tool axis direction maintenance pulse (a + δa, b + δb, 0) to maintain the tool axis direction relative to the A-axis and B-axis.

[0082] The constraint condition calculation unit 108 generates the shift amount (δb) of the constraint condition (b) as a constraint condition interrupt pulse based on the tool axis direction maintaining pulse (a+δa, b+δb, 0).

[0083] The constraint condition setting unit 114 sets the constraint condition interrupt pulse (+δb) as shift information for the rotation axis B in the machine configuration tree held by the machine configuration tree holding unit 110 (for details of shift information, see Japanese Patent No. 7000634). As a result, as shown in the following equation (5), the kinematic conversion unit 105 corrects the fixed coordinate value of the B axis included in the tool attitude pulse from b to b+δb based on the shift information for the rotation axis B, and then generates each axis movement pulse.

number

number

[0084] In this way, in the second application example, the control device 10 performs machine locking while maintaining the tool axis direction for the rotation axis (C axis) whose singularity distance has become small, thereby allowing the other rotation axes (A axis and B axis) to pass through the singularity without decelerating.

[0085] As described above, according to this embodiment, in the control device 10 that controls the machine tool 20, the machine tool 20 has three or more tool attitude control axes that control the attitude of the tool 25, and the attitude of the tool 25 includes the tool axis direction. The control device 10 is equipped with an interrupt control unit 106 that interrupts an interrupt move command from the machine tool 20 into each axis move command including a move command for at least any of the tool attitude control axes, and generates each axis move command after the interrupt, and a tool axis direction maintaining move generation unit 107 that generates a tool axis direction maintaining move based on each axis move command after the interrupt, in order to maintain the tool axis direction with respect to the workpiece W.

[0086] By having such a configuration, the control device 10 can avoid interference between the workpiece W and the tool 25 by maintaining the tool axis direction relative to the workpiece W even when a manual handle interrupt command is input to a rotation axis (e.g., the C-axis), and can avoid fluctuations in the machining results due to interruption, for example, when machining using the side of the tool 25.

[0087] The control device 10 also includes a kinematic conversion unit 105 that generates each axis movement command based on a tool attitude command including a tool axis direction and a constraint condition that constrains one or more degrees of freedom independent of the tool axis direction, and a constraint condition interrupt control unit 109 that inserts a constraint condition interrupt command into the constraint condition and generates a post-interrupt tool attitude command. The kinematic conversion unit 105 generates each axis movement command based on the post-interrupt tool attitude command in order to maintain the tool axis direction with respect to the workpiece W.

[0088] By having such a configuration, when a manual handle interrupt command is input, the control device 10 can maintain the tool axis direction relative to the workpiece W using each axis movement command generated based on the post-interrupt tool attitude command.

[0089] The control device 10 further includes a constraint condition calculation unit 108 that generates a constraint condition interrupt command based on the tool axis direction maintaining movement. A constraint condition interrupt control unit 109 causes the constraint condition interrupt command to interrupt the tool attitude command, and generates a post-interrupt tool attitude command.

[0090] With this configuration, the control device 10 generates a post-interrupt tool attitude command that feeds back the tool axis direction maintenance movement, thereby enabling the control device 10 to generate each axis movement command from the post-interrupt tool attitude command using the kinematic conversion unit 105.

[0091] Therefore, the control device 10 can generate each axis movement command that maintains the tool axis direction relative to the workpiece using the kinematic conversion unit 105. Therefore, the control device 10 can reduce the calculation load compared to when the tool axis direction maintaining movement generation unit 107 generates the tool axis direction maintaining movement relative to the workpiece.

[0092] The control device 10 further includes an interpolation unit 102 that generates post-interrupt tool posture pulses based on a post-interrupt tool posture command, and a pulse generation unit 103 that generates drive pulses for driving tool posture control axes. A kinematic conversion unit 105 generates axis movement pulses as individual axis movement commands based on the post-interrupt tool posture pulses. An interrupt control unit 106 inserts the interrupt movement pulses into the axis movement pulses as the interrupt command, and generates post-interrupt individual axis movement pulses as post-interrupt individual axis movement commands. A tool axis direction maintaining movement generation unit 107 generates tool axis direction maintaining pulses as tool axis direction maintaining movements based on the post-interrupt individual axis movement pulses. The pulse generation unit 103 generates drive pulses based on the tool axis direction maintaining pulses.

[0093] With this configuration, the control device 10 can maintain the tool axis direction relative to the workpiece W by generating a drive pulse from a tool axis direction maintaining pulse as a tool axis direction maintaining movement.

[0094] The control device 10 also includes a machine configuration tree storage unit 110 that stores a machine configuration tree that represents the machine configuration of the machine tool 20 using a tree structure. The kinematic conversion unit 105 converts the post-interrupt tool attitude command into each axis movement command based on the machine configuration tree stored in the machine configuration tree storage unit 110. By including such a configuration, the control device 10 can shift the phase information of the tool 25 stored in the node representing the tool 25 in the machine configuration tree.

[0095] The above has described an embodiment of the present invention, but the above control system 1 can be realized by hardware, software, or a combination of these. Furthermore, the control method performed by the above control system 1 can also be realized by hardware, software, or a combination of these. Here, "realized by software" means that it is realized by a computer reading and executing a program.

[0096] The program can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (e.g., hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (Random Access Memory)).

[0097] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0098] The following additional notes are provided regarding the above-described embodiment and modifications. (Appendix 1) A control device (10) for controlling a machine tool (20), The machine tool (20) includes three or more tool attitude control axes for controlling the attitude of a tool, and the attitude of the tool includes a tool axis direction; The control device (10) an interrupt control unit (106) that interrupts an interrupt movement command from the machine tool into each axis movement command including a movement command for at least one of the tool attitude control axes, and generates each axis movement command after the interrupt; a tool axis direction maintaining movement generating unit (107) that generates a tool axis direction maintaining movement based on the post-interrupt each axis movement command in order to maintain the tool axis direction with respect to the workpiece; A control device (10) comprising: (Appendix 2) a kinematic conversion unit (105) that generates each axis movement command based on a tool attitude command including the tool axis direction and a constraint condition that constrains one or more degrees of freedom independent of the tool axis direction; a constraint condition interrupt control unit (109) that interrupts the constraint condition with a constraint condition interrupt command and generates a tool attitude command after the interrupt; Further provided with The kinematic conversion unit (105) generating each axis movement command based on the post-interrupt tool attitude command in order to maintain the tool axis direction relative to the workpiece; 2. The control device (10) according to claim 1. (Appendix 3) The control device (10) according to Supplementary Note 2, wherein the constraint condition is a tool phase direction. (Appendix 4) The control device (10) according to appendix 2, wherein the constraint condition is a command value for a tool attitude control axis. (Appendix 5) a tool phase direction constraint condition calculation unit (108) that generates the constraint condition interrupt command based on the tool axis direction maintaining movement, the constraint condition interrupt control unit (109) causes the constraint condition interrupt command to interrupt the tool attitude command, and generates a post-interrupt tool attitude command; 10. The control device (10) according to claim 2. (Appendix 6) an interpolation unit (102) that generates a post-interrupt tool posture pulse based on the post-interrupt tool posture command; a pulse generating unit (103) that generates a drive pulse for driving the tool attitude control axis; Further provided with The kinematic conversion unit (105) generates an axis movement pulse as each axis movement command based on the post-interrupt tool attitude pulse, The interrupt control unit (106) causes an interrupt movement pulse to be inserted into the axis movement pulse as the interrupt command, and generates post-interrupt movement pulses for each axis as the post-interrupt movement command for each axis; the tool axis direction maintaining movement generating unit (107) generates a tool axis direction maintaining pulse as the tool axis direction maintaining movement based on the post-interrupt each axis movement pulse; The pulse generating unit (103) generates the drive pulse based on the tool axis direction maintaining pulse. 4. The control device (10) according to claim 3. (Appendix 7) further comprising a machine configuration tree holding unit (110) for holding a machine configuration tree that represents the machine configuration of the machine tool (20) using a tree structure; the kinematic conversion unit (105) converts the post-interrupt tool attitude command into each axis movement command based on the machine configuration tree held by the machine configuration tree holding unit (110); 4. The control device (10) according to claim 3. [Explanation of symbols]

[0099] 1. Control System 10 Control device 20 Machine tools 11 CPU 12 ROM 13 RAM 14 CMOS memory 15, 18, 19 Interface 16 PMC 17 I / O units 31, 32, 33, 34, 35, 36 axis control circuit 41, 42, 43, 44, 45, 46 Servo amplifier 51, 52, 53, 54, 55, 56 Servo motors 60 Bus 70 Display / MDI unit 71 Control panel 711 Manual Handle 72 External equipment 101 Command analysis section 102 Interpolation section 103 Pulse generation unit 104 Servo control unit 105 Kinematic conversion unit 106 Interrupt control unit 107 Tool axis direction maintenance movement generation unit 108 Constraint Condition Calculation Unit 109 Constraint condition interrupt control unit 110 Mechanical configuration wood holding part 111 Location Management Department 112 Singularity distance calculation part 113 Machine lock pulse generator 114 Constraint Condition Setting Section double work

Claims

1. A control device for controlling a machine tool, the machine tool includes three or more tool attitude control axes that control the attitude of a tool relative to a workpiece machined by the machine tool, the attitude of the tool including a tool axis direction; The control device an interrupt control unit that interrupts an interrupt movement command from the machine tool into each axis movement command including a movement command for at least one of the tool attitude control axes, and generates each axis movement command after the interrupt; a tool axis direction maintaining movement generating unit that generates a tool axis direction maintaining movement based on the post-interrupt each axis movement command in order to maintain the tool axis direction with respect to the workpiece machined by the machine tool; A control device comprising:

2. a kinematic conversion unit that generates each axis movement command based on a tool attitude command including the tool axis direction and a constraint condition that constrains one or more degrees of freedom independent of the tool axis direction; a constraint condition interrupt control unit that generates a post-interrupt tool attitude command based on an interrupt command for the constraint condition; Further provided with The kinematic conversion unit is generating each axis movement command based on the post-interrupt tool attitude command in order to maintain the tool axis direction relative to the workpiece; The control device according to claim 1 .

3. The control device according to claim 2 , wherein the constraint condition is a tool phase direction.

4. The control device according to claim 2 , wherein the constraint condition is a command value for the tool attitude control axis.

5. a constraint condition calculation unit that generates the constraint condition interrupt command based on the tool axis direction maintaining movement, the constraint condition interrupt control unit interrupts the constraint condition interrupt command into the tool attitude command to generate a post-interrupt tool attitude command; The control device according to claim 2 .

6. an interpolation unit that generates a post-interrupt tool posture pulse based on the post-interrupt tool posture command; a pulse generating unit that generates a drive pulse for driving the tool attitude control axis; Further provided with the kinematic conversion unit generates an axis movement pulse as each axis movement command based on the post-interrupt tool attitude pulse; the interrupt control unit causes an interrupt movement pulse to be inserted into the axis movement pulse as the interrupt command, and generates post-interrupt each axis movement pulse as the post-interrupt each axis movement command; the tool axis direction maintaining movement generating unit generates a tool axis direction maintaining pulse as the tool axis direction maintaining movement based on the post-interrupt each axis movement pulse; the pulse generating unit generates the drive pulse based on the tool axis direction maintaining pulse. The control device according to claim 5 .

7. a machine configuration tree holding unit that holds a machine configuration tree that represents a machine configuration of the machine tool using a tree structure, the kinematic conversion unit converts the post-interrupt tool attitude command into each axis movement command based on the machine configuration tree held by the machine configuration tree holding unit. The control device according to claim 5 .

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