Control device and computer-readable recording medium

Abstract

A control device according to the present disclosure is provided with: an analysis unit that analyzes a command of a control program; a corner detection unit that detects, on the basis of the analysis result of the analysis unit, a corner part in which the direction of the movement path becomes discontinuous; a corner curvilinear processing unit for curvilinear the corner section by inserting a curve into the corner section, and adjusting the speed on the curvilinear movement path; and a velocity analysis unit for each direction that analyzes a velocity change in a direction component of a forward and backward movement path of the corner section when the corner section moves on the inserted curve, the velocity analysis unit for each direction issues a command to the corner curvification processing unit when a fluctuation in the velocity change during movement on the curve is detected as a result of the analysis, and the corner curvification processing unit performs curvification processing on the corner section when the fluctuation in the velocity change during movement on the curve is detected. A change in corner curve processing for eliminating fluctuations in speed changes on the curve is made.

Description

Technical Field

[0001] The present invention relates to a control device and a computer-readable recording medium. Background Art

[0002] In industrial machinery such as machine tools having multiple feed axes, when a tool is moved along a discontinuous path such as a right-angle corner at a processing point, the feed speed is reduced at the corner or the shape of the corner is rounded so that no impact is generated when passing the corner (for example, Patent Document 1, etc.).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 09-190211 Summary of the invention

[0006] Problems to be solved by the invention

[0007] As a way to round the shape of the corner, consider inserting a circular arc, a spline curve, a clothoid curve, etc. However, if the speed control at this time is not done well, the speed waveform of each feed axis becomes an undulating shape. Moreover, sometimes due to this reason, impact caused by the change of acceleration or reduction in processing accuracy occurs.

[0008] Therefore, it is important not only to round the shape of the corner portion but also to reduce the feed speed.

[0009] Means for solving problems

[0010] The control device disclosed in the present invention estimates the speed in each direction before the curve when the tool moves along the path after the corner is curved, and determines the passing speed of the corner in a manner that the rate of change of the speed in each direction changes monotonically. In this way, the smoothness of the speed change based on the curve and the reduction of the impact of each axis are taken into account to solve the above-mentioned problem.

[0011] Furthermore, one embodiment of the present invention is a control device that drives a feed axis of an industrial machine according to a control program, the control device comprising: an analysis unit that analyzes instructions of the control program; a corner detection unit that detects a corner portion where the direction of a moving path becomes discontinuous based on an analysis result of the analysis unit; a corner curve processing unit that curves the corner portion by inserting a curve into the corner portion and adjusts the speed on the curved moving path; and a speed analysis unit in each direction that analyzes speed changes of directional components of the moving path before and after the corner portion when moving on the inserted curve, wherein, when a fluctuation in speed change during movement on the curve is detected as a result of the analysis, the speed analysis unit in each direction issues an instruction to the corner curve processing unit to change the corner curve processing for eliminating the fluctuation in speed change on the curve.

[0012] Another aspect of the present disclosure is a computer-readable recording medium, which records a program that causes a computer to act as a control device that drives a feed axis of an industrial machine according to a control program, the program causing the computer to act as the following components: an analysis unit that analyzes instructions of the control program; a corner detection unit that detects a corner portion where the direction of a moving path becomes discontinuous based on an analysis result of the analysis unit; a corner curve processing unit that curves the corner portion by inserting a curve into the corner portion and adjusts the speed on the curved moving path; and a speed analysis unit in each direction that analyzes speed changes of directional components of the moving path before and after the corner portion when moving on the inserted curve, wherein, when a result of the analysis is that a fluctuation in speed change during movement on the curve is detected, the speed analysis unit in each direction issues an instruction to the corner curve processing unit to change the corner curve processing for eliminating the fluctuation in speed change on the curve.

[0013] Effects of the Invention

[0014] According to one embodiment of the present disclosure, when each moving object is moved along a path formed by curving the corner, the passing speed of the corner is determined in a manner that the rate of change of the speed in each direction changes monotonically, so that the behavior in each direction is stable and the impact on the machine can be suppressed. In addition, it is also expected that the processing accuracy of the corner can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic hardware configuration diagram of a control device according to one embodiment of the present invention.

[0016] Figure 2 This is a block diagram showing the schematic functions of a control device according to one embodiment of the present invention.

[0017] Figure 3This is a diagram illustrating a corner portion in a moving path.

[0018] Figure 4 This is a diagram illustrating an example of a movement path in which a curve is inserted.

[0019] Figure 5 This is a diagram illustrating changes in acceleration of each directional component when moving on a curve.

[0020] Figure 6 This is a diagram illustrating changes in the speed and the acceleration of a predetermined directional component when moving on a curve. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] Figure 1 1 is a schematic hardware structure diagram of the main part of the control device of one embodiment of the present invention. The control device 1 of the present invention can be installed as a control device for controlling industrial machinery such as a machine tool and a robot having a moving object that is moved by a motor. The following description takes the control device 1 of a machine tool that controls a workpiece by controlling the relative position of a tool and a workpiece as an example.

[0023] The CPU 11 included in the control device 1 of the present invention is a processor that controls the control device 1 as a whole. The CPU 11 reads a system program stored in the ROM 12 via the bus 22, and controls the control device 1 as a whole according to the system program. The RAM 13 temporarily stores temporary calculation data, display data, and various data input from the outside.

[0024] The nonvolatile memory 14 is composed of, for example, a memory backed up by a battery (not shown), an SSD (Solid State Drive), etc., and maintains the storage state even when the power supply of the control device 1 is turned off. The nonvolatile memory 14 stores control programs and data read from the external device 72 via the interface 15, data and control programs input via the input device 71, and various data obtained from the industrial machine 3. The control programs and data stored in the nonvolatile memory 14 can also be expanded in the RAM 13 when executed / used. In addition, various system programs such as well-known analysis programs are pre-written in the ROM 12.

[0025] The interface 15 is an interface for connecting the CPU 11 of the control device 1 to an external device 72 such as a USB device. For example, a control program, various parameters, etc. used for controlling the industrial machine 3 can be read from the external device 72 side. In addition, the control program, various parameters, etc. edited in the control device 1 can be stored in an external storage unit via the external device 72. The PLC (Programmable Logic Controller) 16 outputs signals to the industrial machine 3 and the peripheral devices of the industrial machine 3 (for example, tool changers, actuators such as robots, sensors installed on the industrial machine 3, etc.) through the timing program built into the control device 1 and controls it through the I / O unit 17. In addition, the PLC 16 receives signals from various switches and peripheral devices of the operating panel equipped on the main body of the industrial machine 3, and transmits them to the CPU 11 after necessary signal processing.

[0026] The display device 70 outputs and displays various data read into the memory, data obtained as a result of executing the control program, the system program, etc., via the interface 18. In addition, the input device 71 composed of a keyboard, a pointing device, etc. transmits instructions, data, etc. based on the operator's operation to the CPU 11 via the interface 19.

[0027] The axis control circuit 30 for controlling the axis of the industrial machine 3 receives the axis movement instruction from the CPU 11, and outputs the axis instruction to the servo amplifier 40. The servo amplifier 40 receives the instruction and drives the servo motor 50 that moves each moving object of the industrial machine 3 along the axis. The servo motor 50 of the axis has a built-in position / speed detector, and the position / speed feedback signal from the position / speed detector is fed back to the axis control circuit 30. The axis control circuit 30 performs feedback control of the position / speed of the servo motor 50. In addition, Figure 1 In the hardware structure diagram of FIG, one axis control circuit 30, one servo amplifier 40, and one servo motor 50 are shown, but in reality, the number of axes of the industrial machine 3 to be controlled is prepared. For example, when controlling a general machine tool with three linear axes, three sets of axis control circuits 30, servo amplifiers 40, and servo motors 50 are prepared to relatively move the spindle with the tool mounted thereon and the workpiece in the directions of the three linear axes (X-axis, Y-axis, and Z-axis).

[0028] The spindle control circuit 60 receives the spindle rotation command and outputs a spindle speed signal to the spindle amplifier 61. The spindle amplifier 61 receives the spindle speed signal and rotates the spindle motor 62 of the industrial machine 3 at the instructed rotation speed to drive the spindle. The spindle motor 62 is combined with a position encoder 63. The position encoder 63 outputs a feedback pulse in synchronization with the rotation of the spindle, and the feedback pulse is read by the CPU 11.

[0029] Figure 2This is a diagram showing the functions of a control device 1 according to an embodiment of the present invention as a schematic block diagram. The control device 1 according to this embodiment controls the relative position of a rotating tool and a workpiece, and cuts the workpiece by bringing the tool into contact with the workpiece. The functions of the control device 1 according to this embodiment are shown in FIG. Figure 1 This is achieved by the CPU 11 included in the control device 1 executing a system program to control the operation of each unit of the control device 1 .

[0030] The control device 1 of the present embodiment includes an analyzing unit 100, a corner detecting unit 110, a corner curve processing unit 120, a corner curve forming unit 122, a curve speed planning unit 124, a speed analysis unit 130 for each direction, an axis acceleration / deceleration unit 150, and a control unit 160. In addition, a control program 200 for controlling the industrial machine 3 is stored in advance in the RAM 13 or the nonvolatile memory 14 of the control device 1.

[0031] The analysis unit 100 reads out the program blocks of the control program 200 in sequence. Then, the instructions of the read program blocks are analyzed. The control program 200 includes instructions such as the movement amount, movement path, and movement speed of the feed axis. The analysis unit 100 analyzes these instructions and generates data related to the movement instructions for controlling the positions of the servo motors 50. In addition, when the control program 200 includes instructions for the rotation speed of the spindle, data related to the spindle rotation instructions for controlling the rotation of the spindle motor 62 are generated. Preferably, the analysis unit 100 pre-reads and analyzes the program blocks of the control program 200. The analysis unit 100 outputs the data related to the generated instructions to the corner detection unit 110.

[0032] The corner detection unit 110 detects a corner portion where the direction of the moving path becomes discontinuous based on the data related to the moving command input from the analysis unit 100. In this specification, in two continuous moving paths P1 and P2, the portion where the direction of the front moving path P1 and the direction of the rear moving path P2 are discontinuously connected is called a corner portion. Figure 3 Indicates an example of a corner. Figure 3 In the example of FIG. 1 , the direction of the moving path P1 before the corner portion is connected to the direction of the moving path P2 after the corner portion at a substantially right angle. Figure 3 In addition to the examples shown, the paths may be connected at a more acute angle or at a more obtuse angle. In addition, the movement paths P1 and P2 before and after the corner do not need to be straight lines, but may be curved lines. The corner detection unit 110 detects the connection point of each movement path based on the data related to the movement command input from the analysis unit 100. For example, the angle formed by the movement paths before and after the connection point is a predetermined angle θ determined in advance. th (θ th<180°), the connection point is detected as a corner.

[0033] The corner curve processing unit 120 curves the corner detected by the corner detection unit 110 and adjusts the speed on the curved moving path. The corner curve processing unit 120 includes a corner curve forming unit 122 and a curve speed planning unit 124 .

[0034] The corner curve forming unit 122 inserts a curve into the corner detected by the corner detecting unit 110 as a new movement path. Figure 4 2 shows an example of a curve that the corner curve forming unit 122 inserts into a corner portion. The corner curve forming unit 122 forms a curve P having a predetermined point Ps on the moving path before the corner portion as a starting point and a predetermined point Pe on the moving path after the corner portion as an end point. i The corner portion C is inserted. At this time, the inserted curve is such that the shortest distance from the connection point of the movement paths P1 and P2 is a predetermined allowable path error e p The following curve. Then, the moving path P1 before the corner is replaced by the moving path P1' whose end point is point Ps, and the moving path P2 after the corner is replaced by the moving path P2' whose starting point is point Pe, thereby generating a new moving path. The inserted curve only needs to be roughly continuous with the moving paths P1' and P2' before and after the corner in position, velocity, and acceleration at both ends. In addition, it is preferred that the inserted curve is a curve that can be differentiated by multiple orders of second order or higher. Such curve insertion processing is well known in, for example, Japanese Patent Publication No. 09-190211, Japanese Patent Publication No. 10-320026, etc., so the detailed description in this specification is omitted.

[0035] The curve speed planning unit 124 generates a speed plan when moving on the curve inserted by the corner curve forming unit 122. When generating the speed plan when initially moving on the curve, the curve speed planning unit 124 formulates a speed plan according to the acceleration and deceleration settings set in the control device 1. The curve speed planning unit 124 outputs the speed plan generated here to the speed analysis unit 130 in each direction.

[0036] The speed analysis unit 130 analyzes the speed plan when moving on the curve generated by the curve speed planning unit 124 for the moving path generated by the corner curve forming unit 122. At this time, the speed analysis unit 130 decomposes the speed plan when moving on the curve into the directional components of the moving path before and after the corner, and analyzes the speed change of each directional component. Figure 5 2 is a diagram illustrating the change in speed of the directional components of the moving path before and after the corner portion when moving on a curve. Figure 5As illustrated, on the curve, the speed in the direction of the moving path P1' decelerates as a whole (acceleration gradually approaches 0 from negative), and the speed in the direction of the moving path P2' accelerates as a whole (acceleration gradually increases from 0). However, as it approaches the midpoint of the curve, the deceleration degree of the speed in the direction of the moving path P1' (acceleration in the negative direction) that once weakened temporarily increases, and the acceleration degree of the speed in the direction of the moving path P1' (acceleration in the positive direction) temporarily increases. Such temporary changes in acceleration are affected by the acceleration generated by the shape of the curve (change in curvature), etc. In this way, the change in speed on the curve produces fluctuations, which appear as shocks when moving on the curve. The speed analysis unit 130 in each direction detects such fluctuations in speed changes on the curve (temporary changes in acceleration) as changes in the sign of the rate of change of acceleration (the presence of an extreme value in acceleration).

[0037] As a result of the analysis, if the speed analysis unit 130 does not detect the fluctuation of the speed change on the curve, it issues an instruction to the corner curve processing unit 120 to operate each axis based on the generated speed plan. On the other hand, if the speed analysis unit 130 detects the fluctuation of the speed change on the curve as a result of the analysis, it instructs the corner curve processing unit 120 to change the corner curve processing for eliminating the fluctuation of the speed change on the curve.

[0038] As an example of changing the corner curve processing to eliminate the fluctuation of speed change on the curve, there is changing the allowable path error e of the corner part. p In this method, the main method is to reduce the allowable path error e p The purpose is to bring the positions where the maximum point and the minimum point of acceleration occur close to each other. This can prevent the sign of the rate of change of acceleration from changing, and prevent the fluctuation of speed change.

[0039] As another example of changing the corner curve processing for eliminating the fluctuation of speed change on the curve, there is a method of changing the speed before and after the fluctuation of speed change occurs. In this method, the purpose is to eliminate the maximum point and the minimum point of acceleration by increasing the speed before and after the fluctuation of speed change occurs. Figure 6 This is a graph showing an example of the velocity on a curve and the acceleration of one direction component. If a fluctuation in velocity occurs while moving on a curve, Figure 6 As shown in the example, the change in acceleration has a maximum point and a minimum point. fs ~P fe In the case of, by increasing the speed in this range, the acceleration of each directional component in this range can be increased, and the maximum point and the minimum point can be eliminated. Thus, the fluctuation of speed change can be prevented.

[0040] As another example of changing the corner curve processing for eliminating the fluctuation of speed change on the curve, there is a method of changing the acceleration of the predetermined direction component before and after the fluctuation of speed change occurs. In this method, for example, the purpose is to eliminate the maximum point and the minimum point of acceleration by reducing the absolute value of the acceleration of the predetermined direction component before and after the fluctuation of speed change occurs. That is, by reducing Figure 6 The range P of the fluctuation in speed change is shown as follows: fs ~P fe The absolute value of the acceleration in the velocity can be reduced to near 0, which can eliminate the maximum and minimum points. This can prevent the fluctuation of the velocity change.

[0041] When the speed analysis unit 130 detects the fluctuation of the speed change on the curve, it instructs the corner curve processing unit 120 to change at least one of the above corner curve processing. The corner curve processing unit 120 receives the change instruction and determines whether the instruction is the allowable path error e p In the case of a change instruction, the corner curve forming unit 122 is instructed to perform a change to satisfy the allowable path error e after the change. p In addition, when the instruction is a speed or acceleration change instruction, an instruction is issued to the curve speed planning unit 124 to formulate a speed plan in which the speed or acceleration in the indicated range is changed. After that, the speed analysis unit 130 in each direction analyzes the speed plan generated again. This operation is repeated until the fluctuation of the speed change is no longer detected. Finally, when a moving path and a speed plan that do not generate fluctuations in the speed change are generated, the generated moving path and speed plan are output to the acceleration and deceleration unit 150 of each axis together with the data of the moving instruction.

[0042] The axis acceleration / deceleration unit 150 calculates the movement amount of each axis of the industrial machine 3 per control cycle based on the movement path and speed plan without fluctuation generated by the corner curve processing unit 120 , and performs acceleration / deceleration processing on the calculated movement amount.

[0043] The control unit 160 controls the motors of the industrial machine 3 based on the movement amount after the acceleration / deceleration processing by the axis acceleration / deceleration unit 150 and the data related to the spindle rotation command.

[0044] The control device 1 with the above structure determines the passing speed of the corner portion in a manner that the rate of change of the speed in each direction changes monotonically when each moving object moves along the path after the corner portion is curved, so the behavior in each direction is stable and the impact on the machine can be suppressed. In addition, it can also be expected that the processing accuracy of the corner portion will be improved.

[0045] As mentioned above, although embodiment of this invention was described, this invention is not limited only to the example of the said embodiment, It can implement in various forms by adding appropriate changes.

[0046] Description of Reference Numerals

[0047] 1. Control device

[0048] 3Industrial Machinery

[0049] 11 CPU

[0050] 12 ROM

[0051] 13 RAM

[0052] 14 Non-volatile memory

[0053] Interfaces 15, 18, and 19

[0054] 16 PLC

[0055] 17 I / O Units

[0056] 22 bus

[0057] 30-axis control circuit

[0058] 40 Servo Amplifier

[0059] 50 Servo motor

[0060] 60 spindle control circuit

[0061] 61 Spindle Amplifier

[0062] 62 Spindle motor

[0063] 63 position encoder

[0064] 70 Display device

[0065] 71 Input device

[0066] 72 External devices

[0067] 100 Analysis Department

[0068] 110 Corner Detection Unit

[0069] 120 Corner curve processing unit

[0070] 122 Corner Curve

[0071] 124 Curve Speed ​​Planning Department

[0072] 130 Speed ​​Analysis Department in Each Direction

[0073] 150 Each axis acceleration and deceleration unit

[0074] 160 Control Department

[0075] 200 control program.

Claims

1. A control device for driving a feed axis of an industrial machine according to a control program, characterized in that: The control device comprises: an analyzing unit that analyzes instructions of the control program; a corner detection unit that detects a corner portion where the direction of the moving path becomes discontinuous based on the analysis result of the analysis unit; a corner curve processing unit for performing curve forming by inserting a curve into the corner portion and adjusting a speed on the curved moving path; and a speed analysis unit for each direction that analyzes the speed change of the directional components of the moving path before and after the corner portion when moving on the inserted curve, When the analysis result shows that the speed analysis unit detects the fluctuation of the speed change in the movement on the curve, the speed analysis unit issues an instruction to the corner curve processing unit to change the corner curve processing for eliminating the fluctuation of the speed change on the curve.

2. The control device according to claim 1, characterized in that: The corner curve processing unit includes: a corner curve unit that generates a new movement path by inserting a curve into the corner portion; When the speed analysis unit detects a fluctuation in the speed change during movement on the curve as a result of the analysis, the speed analysis unit issues an instruction to the corner curve processing unit to reduce the allowable path error of the curve. The corner curve forming unit regenerates a curve that reduces an allowable path error based on the instruction.

3. The control device according to claim 1, characterized in that: The corner curve processing unit includes: a curve speed planning unit that generates a speed plan that determines the speed and acceleration transition when moving on the curve. When the analysis result shows that the speed analysis unit detects the fluctuation of the speed change in the movement on the curve, the unit issues an instruction to the corner curve processing unit so that the speed in the range of the fluctuation of the speed change when moving on the curve becomes larger. The curve speed planning unit regenerates a speed plan that increases a speed in a range where the fluctuation of the speed change occurs based on the instruction.

4. The control device according to claim 1, characterized in that: The corner curve processing unit includes: a curve speed planning unit that generates a speed plan that determines the speed and acceleration transition when moving on the curve. When the analysis result shows that the speed analysis unit detects the fluctuation of the speed change in the movement on the curve, the unit issues an instruction to the corner curve processing unit so that the absolute value of the acceleration in the range where the fluctuation of the speed change occurs when moving on the curve becomes smaller. The curve speed planning unit regenerates a speed plan based on the instruction so as to reduce the absolute value of acceleration in a range where the fluctuation of the speed change occurs.

5. A computer-readable recording medium having a program recorded thereon for causing a computer to operate as a control device for driving a feed axis of an industrial machine according to a control program, wherein: The program causes the computer to operate as the following components: an analysis unit that analyzes instructions of a control program; a corner detection unit that detects a corner portion where the direction of the moving path becomes discontinuous based on the analysis result of the analysis unit; a corner curve processing unit for performing curve forming by inserting a curve into the corner portion and adjusting a speed on the curved moving path; and a speed analysis unit for each direction that analyzes the speed change of the directional components of the moving path before and after the corner portion when moving on the inserted curve, When the analysis result shows that the speed analysis unit detects the fluctuation of the speed change in the movement on the curve, the speed analysis unit issues an instruction to the corner curve processing unit to change the corner curve processing for eliminating the fluctuation of the speed change on the curve.

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