Control device

Abstract

Provided is a technology capable of appropriately setting a waiting time for calculating a leading position, in a control device for an industrial machine that avoids collisions by simulation. A control device 10 is provided with: a drive unit 23 that drives and controls at least one movable part 12; a leading position calculation unit 22 that calculates a leading position of the movable part 12 that is a prescribed time ahead of the current position of the movable part 12; a collision checking unit 26 that checks whether or not the movable part 12 will collide with other objects using the leading position of the movable part 12; a state acquisition unit 24 that acquires the operating state of the movable part 12; and a leading speed change unit 25 that changes the relative change speed of the movable part 12 at the assumed leading position with respect to the movable part 12 at the current operating position using the operating state and / or the time required to accelerate or decelerate the movable part 12.

Description

Control device

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

[0002] Conventionally, control devices for controlling industrial machinery using machine tools and robots have been equipped with a function to prevent collisions between structures (tools, workpieces, jigs, etc.) as they have become more multi-axis, multi-system, and highly functional (e.g., Patent Documents 1 to 3).

[0003] Japanese Patent Application Laid-Open No. 2006-124499 (Patent Document 1) relates to a collision prevention device that performs a simulation to check for interference before executing a program command. In this patent document, the simulation is performed before the moving part moves, and the simulation is performed according to the feed rate specified in the execution data.

[0004] Patent Document 2 relates to a collision prevention device that includes a drive control means and an execution management means for a movable part, and that prevents collisions by performing an interference check in advance based on a command path. Patent Document 2 also performs a simulation in advance based on the current position of the movable part.

[0005] Patent Document 3 relates to a method for preventing collisions of a machine tool that is provided with a drive control means for a movable part and that prevents collisions of the machine tool by simulation prior to performing machining. In Patent Document 3, the feed movement state of the tool post of the machine tool is acquired, and a simulation is performed in advance of the current position of the movable part.

[0006] JP 2012-058976 A JP 2010-092161 A JP 2011-014029 A

[0007] When simulating the position of a moving part in advance, a wait time is required to set the advance position. Because the wait time is set uniformly, it may be redundant depending on the operation and situation. For example, since the wait time differs depending on the speed at which multiple axes are operated, it may be possible to shorten the wait time depending on the situation of the axes being operated.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a technology that can appropriately set a waiting time for calculating a preceding position in a control device of industrial machinery that avoids collisions through simulation.

[0009] The present disclosure relates to a control device comprising: a drive unit that drives and controls one or more movable parts; a preceding position calculation unit that calculates a preceding position of the movable part that is a predetermined time ahead of the current position of the movable part; a collision check unit that uses the preceding position of the movable part to check for a collision between the movable part and another object; a status acquisition unit that acquires the operating status of the movable part; and a preceding speed change unit that changes the relative speed of change of the movable part that becomes the virtual preceding position with respect to the actually operating movable part, based on the operating status and / or the time required for acceleration and deceleration of the movable part.

[0010] According to the present disclosure, it is possible to provide a technology that can appropriately set a waiting time for calculating a preceding position in a control device of an industrial machine that avoids collisions through simulation.

[0011] FIG. 1 is a functional block diagram of a control device according to a first embodiment. FIG. 1 is a diagram schematically showing the position of a virtual movable part preceding a movable part at a current position. FIG. 2 is a graph showing the relationship between the virtual preceding position of a movable part and the current position when the X-axis is moved after a cycle start. FIG. 3 is a graph showing the relationship between the virtual preceding position of a movable part and the current position when the Z-axis is moved after a cycle start. FIG. 4 is a diagram schematically showing an industrial machine performing a measurement operation. FIG. 5 is a graph showing the positional relationship between a movable part that actually moves during a measurement operation and a movable part at a virtual preceding position. FIG. 6 is a graph showing the relationship between the virtual preceding position of a movable part and the current position when the rate of change is not changed. FIG. 7 is a graph showing the relationship between the virtual preceding position of a movable part and the current position when the rate of change is changed.

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the second and subsequent embodiments, the same reference numerals will be used to designate components common to the first and second embodiments, and the description thereof will be omitted as appropriate.

[0013] First Embodiment FIG. 1 is a functional block diagram of a control device 10 according to a first embodiment.

[0014] The control device 10 is a computer including hardware such as a processor, a main memory device, an auxiliary memory device, etc. The control device 10 controls the operation of the industrial machine 2 based on input information that specifies the operation, such as a machining program and manual operation input values ​​by an operator.

[0015] The industrial machine 2 is, for example, a machine tool or a robot that operates based on the contents specified in a machining program or the contents input by manual operation. The industrial machine 2 has a movable part 12 that moves to perform machining on a workpiece.

[0016] The control device 10 of the first embodiment includes functional units that operate on a computer processor, such as a current position calculation unit 21, a preceding position calculation unit 22, a drive unit 23, a status acquisition unit 24, a preceding speed change unit 25, and a collision check unit 26.

[0017] The current position calculation unit 21 acquires the current position of the movable unit 12. The current position calculation unit 21 outputs the acquired information on the current position to the previous position calculation unit 22 and the drive unit 23.

[0018] The current position calculation unit 21 can acquire the current position from, for example, the position, velocity, acceleration, and jerk of each axis belonging to the movable part 12 of the industrial machine 2, as well as signals and sensor data associated with each. The associated signals are, for example, information related to operation, such as an in-position signal output upon detecting that the motor position has reached a designated position, a signal indicating whether the coolant is on or off, or a signal indicating whether the spindle rotation is on or off. The sensor data is, for example, information detected by an acceleration sensor. Alternatively, the current position calculation unit 21 may use input information input by a machining program or manual operation to calculate the current position.

[0019] The preceding position calculation unit 22 calculates the preceding position of the movable part 12 that is a predetermined time TA ahead of the current position of the movable part 12. The preceding position can be calculated from information acquired from the machining program or manual operation, information input from the current position calculation unit 21, etc.

[0020] 2 is a diagram schematically showing the position of the movable part 12 preceding the movable part 12 in the current position. In FIG. 2, the movable part 12 in the current position is shown by a solid line, and the movable part 12 in the preceding position is shown by a dashed line.

[0021] The predetermined preceding time TA can be expressed by the following formula (1): By maintaining the predetermined time TA as the preceding time, it is possible to reliably avoid a situation in which a collision occurs between the detection of a collision of the virtual movable part 12 at the preceding position and the stopping of the drive of the actually operating movable part 12.

[0022] T1: Time required to notify that a collision of the movable part 12 at the preceding position has been detected. T2: Time required to perform the process of stopping the movable part 12. T3: Maximum time required for the movable part 12 to stop after starting to decelerate. T4: Margin.

[0023] Note that T3 differs depending on conditions such as the drive shaft of the industrial machine 2, the feed speed, the type of feed (positioning, cutting feed), and the combination of these, and therefore the maximum value expected under each condition is adopted.

[0024] The preceding position calculation unit 22 of this embodiment outputs the calculated preceding position of the movable unit 12 to the collision check unit 26. The configuration of the collision check unit 26 will be described later.

[0025] The driving unit 23 drives and controls one or more movable units 12 included in the industrial machine 2. The driving unit 23 controls the operation of the movable units 12 based on, for example, a position command output from the current position calculation unit 21. The driving unit 23 may also feed back position information output from the movable units 12 to the current position calculation unit 21.

[0026] The state acquisition unit 24 acquires information indicating the operation state of the movable part 12. The state acquisition unit 24 of this embodiment distinguishes between the following three states as the operation state of the movable part 12 and acquires the information.

[0027] The first state is a state immediately after the movable part 12 starts operating. The second state is a state immediately after the movable part 12 completes an operation of detecting contact. The operation of detecting contact in the second state is, for example, an operation of measuring a workpiece using the probe 40. The third state is a state in which the preceding position and the current position are separated by a distance equivalent to the predetermined time. This third state is a state that occurs chronologically later than the first state or the second state.

[0028] The leading speed change unit 25 changes the speed (amount of change) at which the movable part 12 at the virtual leading position is moved based on the state acquired by the state acquisition unit 24 and the type of axis to be operated. The change in the speed of change by the leading speed change unit 25 is a relative change with respect to the speed (amount of change) of the movable part 12 at the current position to be actually operated.

[0029] When an operation to operate the industrial machine 2 is performed, such as pressing a cycle start switch, pressing a jog feed switch, or operating a manual handle, a virtual movable part 12 must be set to a leading position as a step before the movable part 12 actually operates, which causes a wait time. The wait time is determined by the time required for the axis of the movable part 12 to start decelerating and stop. However, the time required for this deceleration to stop varies for each axis.

[0030] The collision check unit 26 performs a collision check using the movable part 12 at the virtual preceding position calculated by the preceding position calculation unit 22 to check for the possibility of collision between the movable part 12 being operated and other objects such as fixed objects or movable objects.

[0031] Various methods such as known techniques can be used for the collision check. The collision check unit 26 stores, for example, the contour shapes of tools used in machining the industrial machine 2, the workpiece to be machined, and the contour shape of the industrial machine 2. The collision check unit 26 checks whether interference between the movable part 12 and another object will occur based on the preceding position calculated in consideration of the preceding time.

[0032] Next, with reference to FIGS. 3 and 4, the time required for the movable part 12 set for each axis of the movable part 12 to start deceleration and stop will be described.

[0033] 3 is a graph showing the relationship between the virtual preceding position and the current position of the movable part 12 when moving the X-axis after the cycle start. The graph also shows the X-axis speed that changes with time. In this example, when moving the X-axis after the cycle start, the time required for acceleration and deceleration is long, so the lower limit of the waiting time also becomes large.

[0034] 4 is a graph showing the relationship between the virtual preceding position and the current position of the movable part 12 when moving the Z axis after the cycle start. The graph also shows the Z axis speed that changes with time. In this example, when moving the Z axis after the cycle start, the time required for acceleration and deceleration is short, so the lower limit of the waiting time can also be made small.

[0035] In this example, when operating the Z axis in Figure 4, the lower limit of the waiting time can be made smaller than when operating the X axis in Figure 3, so operation can be started earlier. However, if the waiting time is set uniformly to the maximum value as in the prior art, there is room for shortening the waiting time when operating only the Z axis. In this regard, the leading speed change unit 25 of this embodiment automatically adjusts the changing speed of the virtual movable part 12 so as to shorten the waiting time depending on the state of the axis being used.

[0036] Next, the control for changing the rate of change will be described using as an example a configuration in which the industrial machine 2 executes a measurement operation by pressing the probe 40 against a workpiece.

[0037] First, the stage before changing the rate of change will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram schematically showing the industrial machine 2 performing a measurement operation. Fig. 6 is a graph showing the positional relationship between the movable part 12 that actually operates during the measurement operation and the movable part 12 at a virtual preceding position. Fig. 6 shows the relationship between the position of the movable part 12 on the X-axis and the Z-axis and the time.

[0038] As shown in FIG. 5, a measurement operation for detecting contact between structures, such as when the probe 40 is pressed against the workpiece to perform measurement, is premised on a collision.

[0039] First, when the state acquisition unit 24 determines that the virtual movable part 12 has started a detection operation to detect contact between structures, the leading speed change unit 25 sets the processing speed in the X-axis direction to 0 until the movable part 12 at the current position catches up with the movable part 12 at the virtual leading position. The timing for setting the processing speed to 0 is in the section N1 in Figures 5 and 6. When the processing speed becomes 0, the operation stage of the movable part 12 at the virtual leading position and the operation stage of the movable part 12 at the current position become the same.

[0040] The determination of whether or not the state has transitioned to the detection state may be triggered by, for example, detecting a command to start a measurement operation, or may be performed at the timing of a block switch in the program.

[0041] When the state acquisition unit 24 determines that the movable part 12 at the current position has caught up with the movable part 12 at the virtual preceding position, the preceding speed change unit 25 sets the processing speed in the X-axis direction of the movable part 12 at the preceding position to be the same as the processing speed in the X-axis direction of the actually operating movable part 12 until contact is detected (during measurement operation). The time for making the processing speeds the same is performed in the section N2 in Figures 5 and 6. Furthermore, in the section N2, the preceding position calculation unit 22 is controlled not to execute the collision check process.

[0042] When the state acquisition unit 24 detects contact between structures, such as when the probe 40 of the industrial machine 2 comes into contact with a workpiece, the state acquisition unit 24 causes the leading position calculation unit 22 to control the processing time in the Z-axis direction so that the virtual moving part 12 leads the moving part 12 at the current position. This control is performed in the section N3 in Figures 5 and 6.

[0043] Next, control for changing the rate of change will be described with reference to Figures 7 and 8. Figure 7 is a graph showing the relationship between the virtual preceding position and the current position of the movable part 12 when the rate of change is not changed. Figure 7 shows the virtual and actual movement of the X-axis of the movable part 12, for which the time T3 required from the start of deceleration to the stop is set.

[0044] 7, if the time T3 required from the start of deceleration to the stop of the X-axis to be operated is equal to the maximum time (T3) required from the start of deceleration to the stop of each axis, the change rate is not changed. That is, the virtual movable part 12 moves at a constant change rate in the X-axis direction from immediately after the start of operation to the end of the operation. In this example, the waiting time TA = T1 + T2 + T3 + T4, and the operation of the actual movable part 12 starts a predetermined time TA after the start of operation of the virtual movable part 12.

[0045] 8 is a graph showing the relationship between the virtual preceding position and the current position of the movable part 12 when the rate of change is changed. Fig. 8 shows the virtual and actual movements of the Z axis of the movable part 12, for which the time T3' required from the start of deceleration to the stop is set.

[0046] The leading speed change unit 25 changes the rate of change at which the position of the virtual movable part 12 is changed if changing the rate of change can shorten the waiting time. Whether the waiting time can be shortened depends on the operating state and the type of axis being operated. If the time T3' required from the start of deceleration of the Z-axis to its stop is shorter than the maximum time (T3) required from the start of deceleration of each axis to its stop, the rate of change is changed (T3'<T3).

[0047] 8, when the leading speed change unit 25 acquires that the movable part 12 (Z axis) is in a state immediately after the Z axis starts operating in the section N3 (first state) or that the movable part 12 (X axis) is in a state immediately after the movable part 12 (X axis) completes the operation of detecting contact in the section N2 (second state), the leading speed change unit 25 executes a process to change the change speed. Note that if the X axis is the axis that starts operating in the section N3, the change speed is not changed.

[0048] The leading speed change unit 25 executes a process of changing, from a set value, the rate of change at which the position of the virtual movable part 12 is changed. The set value before being changed by the leading speed change unit 25 is a value that is set as the rate of change when the movable part 12 is actually operated.

[0049] The leading speed change unit 25 changes the change speed in order to change the waiting time TA from when the virtual movable part 12 starts moving along the Z axis until when the actually moving movable part 12 starts moving along the Z axis to a waiting time TA' shown in the following formula (2). The leading speed change unit 25 of this embodiment increases the change speed by multiplying the change speed before the change by TA / TA'.

[0050] T1: Time required to notify that a collision of the movable part 12 at the preceding position has been detected. T2: Time required to perform the process of stopping the movable part 12. T3': Time required for the Z axis of the movable part 12 to start deceleration and stop. T4: Margin.

[0051] By changing the rate of change by the leading speed change unit 25, the waiting time from when the virtual movable part 12 starts to operate until when the actual movable part 12 starts to operate becomes shorter after the rate of change (see FIG. 8) than when the rate of change is not changed (see FIG. 7).

[0052] The operation control of the movable part 12 based on the changed change speed continues until the state acquisition unit 24 detects a state (third state) in which the virtual preceding position of the Z axis of the movable part 12 and the current position of the Z axis of the movable part 12 that is actually operated are separated by a distance corresponding to a predetermined time TA.

[0053] When the state acquisition unit 24 detects the third state, it returns the rate of change of the X-axis of the virtual movable part 12 to the rate of change before the change, thereby making the rate of change of the Z-axis of the virtual movable part 12 match the rate of change of the Z-axis of the actually operating movable part 12.

[0054] As described above, the control device 10 of this embodiment includes a drive unit 23 that drives and controls one or more movable parts 12, a leading position calculation unit 22 that calculates the leading position of the movable part 12 that is a predetermined time (TA, TA') ahead of the current position of the movable part 12, a collision check unit 26 that uses the leading position of the movable part 12 to check for collision between the movable part 12 and another object, a status acquisition unit 24 that acquires the operating status of the movable part 12, and a leading speed change unit 25 that changes the relative speed of change of the movable part 12 that is the virtual leading position with respect to the actually operating movable part 12, based on the operating status and / or the time (T3 or T3') required for acceleration and deceleration of the movable part 12.

[0055] As a result, when the movable part 12 actually starts to operate, the speed of change of the movable part 12 at the virtual preceding position is appropriately set in accordance with the time required for acceleration and deceleration of the axis to be operated. When a movable part 12 configuration that requires a short time for acceleration and deceleration is operated, the speed of change is large, so the time until the movable part 12 actually operates can be shortened. A collision check can be performed without unnecessarily delaying the operation of the actual machine relative to the machine operation.

[0056] Furthermore, in this embodiment, when the state acquisition unit 24 acquires the state immediately after the movable part 12 starts operating (first state) or the state immediately after the movable part 12 completes the operation of detecting contact (second state) as the operating state, the leading speed change unit 25 calculates the relative speed of change based on the time required for acceleration / deceleration of the movable part 12 (T3 or T3') and a predetermined time (TA).

[0057] This makes it possible to efficiently obtain the speed of change at the timing when the movement of the movable part 12 at the virtual preceding position starts, through simple processing.

[0058] In addition, in this embodiment, when the state acquisition unit 24 acquires as an operating state a state (third state) in which the movable part 12 at the virtual preceding position is separated from the movable part 12 that is actually operated by a distance equivalent to a predetermined time, the preceding speed change unit 25 makes the change speed of the movable part 12 at each of the preceding position and the current position the same.

[0059] This makes it possible to avoid a situation in which the lead time of the movable part 12 at the virtual lead position exceeds a predetermined time after the timing at which the movable part 12 actually operates, thereby enabling accurate collision checks to be performed.

[0060] The above describes an example in which the industrial machine 2 is controlled by one control device 10. However, the present invention is not limited to the configuration of the above embodiment.

[0061] [Second embodiment] Next, a control device 1 according to a second embodiment, which is different from the first embodiment, will be described. Note that in the configuration of the second embodiment, components common to or similar to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof may be omitted.

[0062] 9 is a functional block diagram of the control device 1 according to the second embodiment. As shown in FIG. 9, the control device 1 according to the second embodiment includes a numerical control device 27 and a collision check device 28.

[0063] The numerical control device 27 includes a current position calculation unit 21, a preceding position calculation unit 22, a drive unit 23, a status acquisition unit 24, and a preceding speed change unit 25. The numerical control device 27 of the second embodiment differs from the control device 10 of the first embodiment in that it does not include a collision check unit 26.

[0064] The collision check unit 26 is arranged in a collision check device 28 outside the numerical control device 27. When the collision check device 28 receives information indicating the leading position of the movable part 12 from the leading position calculation unit 22 of the numerical control device 27, the collision check unit 26 performs a collision check. The method of collision check is the same as in the first embodiment.

[0065] As described above, in the second embodiment, the collision check unit 26 that performs a collision check is disposed outside the numerical control device 27 that also contains the current position calculation unit 21, the preceding position calculation unit 22, the drive unit 23, the status acquisition unit 24, and the preceding speed change unit 25. The configuration of this second embodiment can also achieve the same effects as the first embodiment.

[0066] [Third embodiment] Next, an example of a control device configured with a plurality of numerical control devices and computers will be described. Fig. 10 is a functional block diagram of a control device 1A according to the third embodiment. As shown in Fig. 10, the control device 1A of the third embodiment is configured with a first numerical control device 10a, a second numerical control device 10b, and an information processing device 5.

[0067] The first numerical control device 10a, the second numerical control device 10b and the information processing device 5 are all computers equipped with hardware such as a processor, a main memory device and an auxiliary memory device, and are configured to be able to communicate with other computers.

[0068] The first numerical control device 10a is hardware that controls the industrial machine 2. In the processor of the first numerical control device 10a, a current position calculation unit 21 and a drive unit 23 are executed as functional units. The first numerical control device 10a can also be said to be a machine control system that controls the industrial machine 2 that actually operates.

[0069] The second numerical control device 10b is hardware that controls the virtual machine 3, which corresponds to the movable part 12 at the virtual leading position in the first embodiment. The second numerical control device 10b can also be said to be a leading check system that controls the operation of the virtual machine 3 that imitates the simulated industrial machine 2. In the processor of the second numerical control device 10b, a leading position calculation unit 22 and a collision check unit 30 are executed as functional units.

[0070] The collision check is performed by a collision check unit 30 that controls the virtual machine 3. The collision check method is the same as in the first embodiment.

[0071] The information processing device 5 is hardware that realizes the functions of the state acquisition unit 24 and the preceding speed change unit 25 in the first embodiment. The information processing device 5 may be configured to belong to either the first numerical control device 10a or the second numerical control device 10b.

[0072] The configuration of the third embodiment described above can also achieve the same effects as the first embodiment.

[0073] The present disclosure is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present disclosure are included in the present disclosure. For example, the control device of the above-described embodiment may be realized on a cloud computing system.

[0074] The following supplementary note is further disclosed regarding the above embodiment and modified examples: (Supplementary note 1) A control device (10, 1, 1A) comprising: a drive unit (23) that drives and controls one or more movable parts (12), a preceding position calculation unit (22) that calculates a preceding position of the movable part (12) that is a predetermined time (TA, TA') ahead of the current position of the movable part (12), a collision check unit (26) that checks for a collision between the movable part (12) and another object using the preceding position of the movable part (12), a status acquisition unit (24) that acquires the operating state of the movable part (12), and a preceding speed change unit (25) that changes the relative speed of change of the movable part (12) that becomes the virtual preceding position with respect to the actually operating movable part (12) based on the operating state and / or the time (T3, T3') required for accelerating and decelerating the movable part (12).

[0075] (Supplementary Note 2) In the above control device (10, 1, 1A), when the state acquisition unit (24) acquires the operating state as the state immediately after the movable part (12) starts operating or the state immediately after the movable part (12) completes the operation of detecting contact, the leading speed change unit (25) calculates the relative speed of change based on the time (T3, T3') required for accelerating and decelerating the movable part (12) and the predetermined time (TA, TA').

[0076] (Supplementary Note 3) In the above control device (10, 1, 1A), when the state acquisition unit (24) acquires as the operating state a state in which the movable part (12) at the virtual preceding position is separated from the movable part (12) to be actually operated by a distance equivalent to the predetermined time (TA, TA'), the preceding speed change unit (25) makes the change speed of the movable part at the preceding position and the current position the same.

[0077] 1, 1A, 10 Control device 2 Industrial machine 12 Moving part 21 Current position calculation part 22 Leading position calculation part 23 Driving part 24 Status acquisition part 25 Leading speed change part 26 Collision check part

Claims

1. A control device comprising: a drive unit that drives and controls one or more moving parts; a leading position calculation unit that calculates a leading position of the moving part that is a predetermined time ahead of the current position of the moving part; a collision check unit that uses the leading position of the moving part to check for the presence or absence of a collision between the moving part and another object; a status acquisition unit that acquires the operating status of the moving part; and a leading speed change unit that changes the relative change speed of the moving part that serves as the virtual leading position with respect to the actually operating moving part, based on the operating status and / or the time required for acceleration and deceleration of the moving part.

2. The control device described in claim 1, wherein when the state acquisition unit acquires as the operating state the state immediately after the movable part starts operating, or the state immediately after the movable part completes an operation to detect contact, the leading speed change unit calculates the relative change speed based on the time required for acceleration and deceleration of the movable part and the specified time.

3. The control device described in claim 1, wherein when the state acquisition unit acquires as the operating state a state in which the movable part at the virtual preceding position is separated from the movable part to be actually operated by a distance equivalent to the specified time, the preceding speed change unit makes the change speed of the movable part at each of the preceding position and the current position the same.

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