JP5958166B2 - Robot controller - Google Patents

Description

  The present invention relates to a robot control apparatus for controlling an articulated robot having a plurality of arms.

  An articulated robot having a plurality of arms is provided with a plurality of driving units corresponding to the respective axes. Each drive unit generally includes a motor for driving each shaft and a gear mechanism for transmitting the output of the motor to an arm connected to the output shaft side. This gear mechanism employs, for example, a well-known wave gear device, and the structure itself is generally designed in common, although there is a difference that the number of teeth is different for each axis. Since such a gear mechanism may cause the gear to be damaged when the lubricant is reduced, for example, Patent Document 1 proposes a countermeasure for sufficiently lubricating the operating gear. .

JP 2009-79627 A

Now, industrial devices such as robots are generally assumed to have a useful life in advance, and are designed to withstand the useful life. Specifically, in the case of an articulated robot having a plurality of drive units as described above, the lifespan of each drive unit is designed to be substantially the same.
However, when the robot is actually installed and a predetermined work cycle is repeatedly executed, among the drive units whose service lives should generally match as described above, a specific drive unit is in a shorter period than expected. A failure may result in a decrease in the useful life of the entire robot. In addition, it was difficult to think of a malfunction in the design of the robot, such as a different drive unit for each customer.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a robot control apparatus capable of presenting a drive unit that may fail early in an articulated robot including a plurality of drive units. Is to provide.

  As a result of investigating the failed robot, the inventor found that the drive units that failed in a shorter period than expected were concentrated on the drive units that were not operating during the work cycle. In the case of an articulated robot, there is a possibility of performing various operations, so that a plurality of drive units are provided in consideration of versatility, but there are also drive units that do not operate at all depending on the work contents. In this case, since the gear mechanism does not operate unless the drive unit operates, there is little possibility that the teeth of the gear mechanism will be worn or damaged. Generally speaking, the failure concentrates on the drive unit that is not operating. It is difficult to think about the situation. Therefore, as a result of further detailed analysis of the process in which a failure occurs in the drive unit, the inventor concentrates the failure in the drive unit that is not operating because the configuration of the movable shaft is redundant with respect to the work content. We found that this is a phenomenon unique to articulated robots.

  In an articulated robot, vibration due to the operation of another driving unit or movement of an arm is transmitted to a non-operating driving unit. Since the robot repeatedly executes a predetermined work cycle, vibrations are repeatedly transmitted to a non-operating drive unit. The vibration is also transmitted to the gear mechanism of the drive unit. Lubricating oil having a relatively high viscosity is generally used as a lubricant for the gear mechanism of the drive unit, and the lubricating oil has a property close to a solid in a situation where the gear mechanism is not operating. For this reason, when vibration is transmitted to the gear mechanism, the lubricating oil is partially lost by the vibration, and a missing region where no lubricating oil is present between the teeth of the gear mechanism is first generated in a relatively small range. This missing area gradually expands as the work cycle is repeatedly executed, that is, when vibration is repeatedly transmitted. At that time, the engaged teeth are in direct contact with each other, and further vibrations are repeatedly transmitted in this state. As a result, the directly contacted teeth are damaged, resulting in a failure of the drive unit.

  Therefore, in the invention described in claim 1, the execution instruction given to the robot is analyzed, and the analysis result of a series of execution instructions for executing a predetermined work cycle is stored as an operation history in the work cycle, Based on the motion history, it is determined whether or not there is a non-motion axis that is a drive unit that is not operating during the work cycle among the axes of the robot, and the user is notified that there is a non-motion axis.

  Thus, by actually installing the robot and tracing its operation, it can be shown to the user that there is a drive unit that does not operate during the work cycle. Therefore, it is possible to take measures such as adding an execution command for driving the non-operating axis during the work cycle to the drive unit that may cause a failure as described above. It is possible to suppress the occurrence of failures in In addition, although it is not easy for the user to determine whether or not there is a non-motion axis by visually observing the operation of the robot, it can be easily determined by presenting it.

  According to the second aspect of the present invention, the movement mode when moving the arm between preset teaching points is a movement operation that places importance on the movement trajectory of the arm and movement that places importance on the movement speed of the arm. It is determined which of the movements, and the period during which the arm is moving is presented as an operable period during which the non-motion axis can be moved. Note that the work movement is when the arm is moved smoothly between teaching points when performing a control that moves the arm smoothly with a relative emphasis on the movement trajectory to perform work such as gripping or assembling the work. This operation is generally called a CP (Continuous Path) operation. In addition, the moving operation is an operation when performing a control to move quickly between teaching points with a relative emphasis on the moving speed when moving the arm between teaching points, in other words, an operation that places little importance on the trajectory. In general, this is called a PTP (Point To Point) operation. Hereinafter, for convenience, the work operation is referred to as a CP operation, and the movement operation is referred to as a PTP operation.

  Although it is possible to take some measures against the drive unit that may fail by presenting the non-operation axis as described above, the user needs to reconsider when to operate the drive unit There is. At this time, for example, if the non-operating axis is moved every time one work cycle is completed, it takes time unnecessary for the original work to execute the next work cycle, which is necessary for performing the work. Time (hereinafter referred to as tact time) becomes longer. And if the tact time becomes longer, it takes more time to handle a predetermined amount of work. On the other hand, if the work time is determined in advance, the number of work cycles that can be executed decreases, and the production efficiency Decreases. For this reason, it is required to operate the target drive unit so as not to affect the tact time.

  Now, it is generally known that the CP operation and the PTP operation described above are included in the work cycle of the robot. Therefore, in order to operate the drive unit without affecting the tact time and without affecting the original work of the robot (without greatly affecting the trajectory of the arm), the operation is performed during the PTP operation. First of all, it can be considered. However, in order to spread the lubricant evenly, for example, if the operation of rotating the meshing position of the teeth of the gear mechanism is performed, the arm moves greatly, and no matter how much the trajectory is in the PTP operation However, there is a possibility that an arm, a hand, or a work held by the hand may collide with peripheral equipment. In other words, it is not a simple problem that when the drive unit should be operated during the PTP operation.

  Here, the analysis result by the inventor is effectively used. That is, the inventor has found that the missing region of the lubricant first occurs in a relatively small range as described above, and further, the missing region at the beginning of the occurrence has a size of less than one tooth. For this reason, in order to diffuse the lubricant into the missing region at the beginning of generation, it is only necessary to mesh with a portion where the lubricant is not missing, that is, if the meshing position of the gear mechanism teeth is moved by one or more teeth. It turned out to be good. In other words, it has become clear that it is not necessary to move the arm greatly in order to deal with the missing area at the beginning of the occurrence. Furthermore, if it is an operation | movement which moves a meshing position 1 or more teeth, it is thought that it can fully implement during PTP operation | movement.

  Based on the support of such an analysis result, the period during which the arm is moving is presented as an operable period during which the non-operating axis can be operated. As a result, the lubricant can be diffused in the missing area at the beginning of the occurrence, and the enlargement of the missing area can be suppressed, and the lubricant is diffused by operating the non-operation shaft. Generation itself can be suppressed. Further, as described above, the operation of the non-operation axis is an operation that can be performed during the PTP operation, and thus is completed during the PTP operation. Therefore, there is no influence such as an increase in tact time, and the possibility that the production efficiency is lowered can be suppressed.

  In the invention according to claim 3, the period in which it is determined that the workpiece is not transferred is preferentially presented. Since the robot operates based on the given command, it cannot normally grasp what kind of workpiece is the target. Therefore, even when a non-motion axis that is not supposed to operate in the original work cycle is operated by giving priority to the period during which the workpiece is not transferred, it is caused by the operation. There is no problem such as the work colliding with peripheral equipment.

  In the invention according to claim 4, when there are a plurality of operable periods in the work cycle, the operable period with the longest operating time is preferentially presented. If the operating time of the operable period is long, even if the non-operating axis is operated, it can be surely returned to its original position, and the trajectory of the arm is not greatly affected, and the non-operating within the operating time. The axis can be moved greatly, and the occurrence and expansion of missing areas can be further suppressed.

  In the invention according to claim 5, since an auxiliary execution command for operating the non-motion axis can be added during the operable period, it becomes possible to operate the robot with the auxiliary execution command added, and the non-operation It can be determined whether or not the axis can be moved.

The figure which shows schematically the structure of the robot made into object by 1st Embodiment of this invention. The figure which shows schematically the electric constitution of the robot system 1 The figure which shows the structure of a drive part roughly Diagram showing the electrical configuration of the teaching pendant The figure which shows an example of CP operation | movement and PTP operation | movement typically FIG. 6 is an enlarged view of the VI region in FIG. 3, schematically showing the transition of the lubricant missing region. Diagram showing the processing flow of the teaching pendant The figure which shows an example of the presentation screen of the teaching pendant The figure which shows schematically the structure of the robot made into object by 2nd Embodiment of this invention.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, a robot system 1 used for general industrial use includes an articulated robot 2, a controller 3 that controls the robot 2, and a teaching pendant 4 connected to the controller 3 (the robot in this embodiment). Equivalent to a control device).

  The robot 2 has a well-known configuration as a so-called 6-axis vertical articulated robot, and the shoulder 6 rotates on the base 5 in the horizontal direction via a first axis (J1) having an axis in the Z direction. Connected as possible. A lower end portion of a lower arm 7 extending upward is connected to the shoulder 6 via a second shaft (J2) having an axis in the Y direction so as to be rotatable in the vertical direction. A first upper arm 8 is connected to the tip of the lower arm 7 via a third axis (J3) having an axis in the Y direction so as to be rotatable in the vertical direction. The second upper arm 9 is connected to the tip of the first upper arm 8 via a fourth axis (J4) having an X-axis axis so as to be able to rotate. A wrist 10 is connected to the tip of the second upper arm 9 via a fifth axis (J5) having an axis in the Y direction so as to be rotatable in the vertical direction. A flange 11 is connected to the wrist 10 via a sixth shaft (J6) having an X-direction axis so as to be able to rotate.

  The base 5, the shoulder 6, the lower arm 7, the first upper arm 8, the second upper arm 9, the wrist 10 and the flange 11 function as the arm of the robot 2, and the illustration of the flange 11 which is the tip of the arm is omitted. However, a hand (also called an end effector) is attached. For example, the hand holds and transfers a workpiece (not shown) or a tool for processing the workpiece is attached. Each axis (J1 to J6) provided in the robot 2 is provided with a drive unit 23 (see FIG. 2) corresponding to each axis.

  As shown in FIG. 2, the controller 3 includes a CPU 12, a ROM 13 and a RAM 14, a drive circuit 15, a position detection circuit 16, and the like. The CPU 12 controls the entire controller 3 based on a program stored in the ROM 13 or the RAM 14 and outputs various commands for causing the robot 2 to repeatedly execute a predetermined work cycle as is well known. To do. The CPU 12 includes a command unit 17, a determination unit 18, and an auxiliary command unit 19. The command unit 17, the determination unit 18, and the auxiliary command unit 19 are configured in software by a program executed by the CPU 12 in this embodiment. Note that the command unit 17, the determination unit 18, and the auxiliary command unit 19 may be configured in hardware.

The command unit 17 individually outputs a drive command for operating the drive unit 23 of the robot 2, that is, an execution command for driving the motor 20 (see FIG. 2), to each drive unit 23. The command unit 17 constitutes command means described in the claims.
The determination unit 18 individually determines whether or not a drive command is output to the robot drive unit 23 during the work cycle, and the movement of the arm during the work cycle is a work operation (CP operation described above) or a movement. It is further determined whether the operation (the PTP operation described above) or whether the workpiece is held during the PTP operation. The determination part 18 comprises the determination means described in the claims. Hereinafter, the work operation is referred to as a CP operation, and the movement operation is referred to as a PTP operation.

  The auxiliary command unit 19 outputs an auxiliary drive command for driving the motor to the drive unit 23 determined not to output a drive command during the work cycle. In the present embodiment, as an auxiliary drive command, an auxiliary drive command that can move one or more teeth in a gear mechanism of a gear mechanism of the speed reducer 22 described later is output. The auxiliary command unit 19 constitutes auxiliary command means described in the claims.

  The drive circuit 15 is constituted by, for example, an inverter circuit that converts an instruction output from the CPU 12 into an electric signal for giving to the robot 2. The robot 2 includes a plurality of motors 20 for driving the first axis J1 to the sixth axis J6 and encoders 21 provided corresponding to the motors 20, respectively. The position detection circuit 16 receives a signal from the encoder 21 that detects the rotational position of the motor 20 and detects the rotational position of the motor 20. The CPU 12 feedback-controls the motor 20 based on the rotational position of the motor 20 detected by the position detection circuit 16.

  In the robot 2, the output of the motor 20 is transmitted to the arm via the speed reducer 22. The motor 20 and the speed reducer 22 constitute a drive unit 23. In FIG. 2, the shoulder 6, the lower arm 7, the first upper arm 8, the second upper arm 9, the wrist 10, and the flange 11 that are driven by the driving units 23 are indicated as arms for convenience. In the present embodiment, a so-called wave gear device is employed as the speed reducer 22.

  As shown in FIG. 3, the speed reducer 22 is provided with an annular rigid internal gear 31 having internal teeth 30 formed on the inner peripheral surface thereof, and is provided concentrically inside the rigid internal gear 31. A flexible external gear 33 having 32 is provided. Although not shown, the flexible external gear 33 is formed in a cup shape as a general shape as is well known, and an output shaft is attached to the cup-shaped bottom portion. Further, between the internal teeth 30 of the rigid internal gear 31 and the external teeth 32 of the flexible external gear 33, a lubricating oil W (see FIG. 5) as a lubricant is filled. This lubricating oil W generally has a relatively high viscosity. If the rigid internal gear 31 and the flexible external gear 33 are operating, the lubricating oil W diffuses between the gears and functions as a lubricant. If not, it will be almost solid. Note that the lubricant is not limited to oil, but may be other.

  A wave bearing 34 is disposed on the inner peripheral side of the outer teeth 32. The wave bearing 34 includes a flexible outer ring 35, a flexible inner ring 36, and a plurality of balls 37 arranged between the flexible outer ring 35 and the flexible inner ring 36. An elliptical rigid cam 38 is fixed on the inner side of the wave bearing 34, that is, on the inner periphery of the flexible inner ring 36. The rigid cam 38 is formed with a fitting hole 39 with a key groove for connecting the output shaft of the motor 20.

  In the speed reducer 22 having such a configuration, the flexible inner ring 36 and the flexible outer ring 35 of the wave bearing 34 are bent in an elliptical shape, and the flexible outer ring 35 is bent in an elliptical shape, whereby the external teeth 32. The forming part is bent into an oval shape. As a result, the external teeth 32 partially mesh with the internal teeth 30 of the rigid internal gear 31 at two locations on both ends in the major axis direction of the elliptically bent portion. When the rigid cam 38 is rotationally driven by the motor 20, the long diameter portion of the flexible external gear 33 bent in an elliptical shape moves in the circumferential direction, and the meshing position of the external teeth 32 with respect to the internal teeth 30. Moves in the circumferential direction. At this time, since the external teeth 32 are set to be, for example, two fewer than the internal teeth 30, the relative movement between the rigid internal gear 31 and the flexible external gear 33 is increased with the movement of the meshing position. Rotation occurs. Then, the speed reduction rotation of the motor 20 is taken out using the flexible external gear 33 as an output shaft.

  As shown in FIG. 1, the teaching pendant 4 as a robot control device is formed in, for example, a thin, substantially rectangular box shape, and is generally large enough to be carried or carried by a user. The teaching pendant 4 is provided with a display unit 4a for performing various displays and switches 4b as operation input units for receiving user operations. The switches 4b are configured by so-called touch panel switches provided on the screen of the display unit 4a, mechanical switches provided around the display unit 4a, and the like.

  As shown in FIG. 4, the teaching pendant 4 includes a CPU 40, a ROM 41, a RAM 42, and an input / output unit 43. The CPU 40 is connected to the display unit 4a and the switches 4b, and controls the teaching pendant 4 as a whole by displaying an operation screen of the teaching pendant 4 and receiving a user operation. The display unit 4a displays an execution screen or an execution result (trace result) of an application program (hereinafter simply referred to as an application) that traces the operation of the robot 2, as will be described later, and is presented to the user. The switches 4b are used to input a holding execution command (described later) to the robot 2. The display unit 4a constitutes the presenting means described in the claims, and the switches 4b constitute the operation input means described in the claims.

The teaching pendant 4 includes a command analysis unit 44, an operation history storage unit 45, a movement mode specifying unit 46, a non-operation axis determination unit 47, and an auxiliary command addition unit 48. In the present embodiment, these units 44 to 48 are realized by software by a program executed by the CPU 40. Each unit 44 to 48 may be realized by hardware.
The command analysis unit 44 analyzes an execution command given to the robot 2. The execution commands given to the robot 2 are roughly classified into operation commands given to the drive unit 23 for driving the arm and control commands such as determination of branch conditions. The instruction analysis unit 44 constitutes instruction analysis means described in the claims.
The operation history storage unit 45 stores an analysis result of a series of execution instructions for the robot 2 to execute a predetermined work cycle as an operation history of the robot 2 in the work cycle. The operation history storage unit 45 constitutes an operation history storage described in the claims.

When the movement mode specifying unit 46 moves the arm between preset teaching points during the work cycle, the movement mode of the arm relatively moves the movement trajectory of the arm (CP operation) or the The moving operation (PTP operation) in which the moving speed of the arm is relatively emphasized is specified. Further, the movement mode specifying unit 46 specifies whether or not the robot 2 is in a transfer state in which a work is held (transferred). The movement mode identification unit 46 constitutes a movement mode identification unit described in the claims.
Based on the motion history stored in the motion history storage unit 45, the non-motion axis determination unit 47 determines whether there is a non-motion axis that is not operating during the work cycle among the axes of the robot 2. The non-operation axis determination unit 47 constitutes non-operation axis determination means described in the claims.

  The auxiliary command adding unit 48 adds an auxiliary execution command (operation command) for operating the non-motion axis during the operable period. In this embodiment, an operation command for moving one or more teeth of the gear mechanism is output as the auxiliary execution command. In this case, in a robot with a general configuration, assuming that the gear ratio of the fourth axis (J4) = 100 and the distance from the center of the fifth axis (J5) to the tip of the hand = 200 mm, the motor rotates once (the motor output). By rotating the shaft once (not rotating the gear mechanism in FIG. 3 once), the tip of the hand moves only about 13 mm (2π ÷ 100 × 200 = 4π) at maximum. The auxiliary command adding unit 48 constitutes auxiliary command adding means described in the claims.

  The teaching pendant 4 may be a terminal device connected to the controller 3. Specifically, the teaching pendant 4 is provided with a display unit 4a and switches 4b. That is, the teaching pendant 4 has a display function and an operation input function, and the controller is used by a communication means such as a cable or wireless communication. 3, the CPU 12 of the controller 3 may execute the various processes described above instead of the CPU 40, and the operation screen and the execution result may be displayed on the teaching pendant 4 side. In that case, the above-described units 44 to 48 may be realized by software or by hardware by a program executed by the CPU 12 of the controller 3. That is, in this embodiment, the teaching pendant 4 alone constitutes the robot control device, but the controller 3 and the teaching pendant 4 may be combined to constitute the robot control device. Alternatively, the controller 3 may have a display function and an operation input function, and the robot controller may be configured by the controller 3 alone.

  The teaching pendant 4 having such a configuration is connected to the controller 3 via a cable, and can perform high-speed data transmission / reception with the controller 3 via the input / output unit 43. Therefore, information such as operation signals input by operating the switches 4b is transmitted from the teaching pendant 4 to the controller 3, and the robot 2 is taught. The teaching pendant 4 also receives data from the controller 3. Specifically, in this embodiment, the teaching pendant 4 receives from the controller 3 a program for executing a work cycle, that is, a series of execution instructions.

Here, a work cycle executed by the robot 2 will be described.
As shown in FIG. 5, the work cycle is a work of repeatedly transferring, for example, a workpiece through predetermined teaching points P1 to P4. For example, in FIG. 5, after moving to the teaching point P2 with the teaching point P1 as the initial position, the workpiece is picked up at the teaching point P3, passed through the teaching points P2 and P1 while holding the workpiece, and then the teaching point P4. A work cycle for placing a work is schematically shown. More specifically, the arm moves greatly in the horizontal direction between the teaching points P1 and P2, and the arm moves vertically between the teaching points P2 and P3 and between P1 and P4.

  In this case, when the arm moves horizontally, for example, the first axis (J1) operates, and when the arm moves vertically, for example, the second axis (J2), the third axis (J3), and the fifth axis (J5). ) Shall operate. In addition, between the teaching points P1 and P2 where the arm greatly moves in the horizontal direction, a movement operation (hereinafter referred to as a PTP operation) with an emphasis on the moving speed is performed, and between the teaching points P2 and P3 that pick up the workpiece from a predetermined position In addition, it is assumed that a work operation (hereinafter referred to as a CP operation) with an emphasis on the movement trajectory is performed between the teaching points P1 to P4 where the workpiece is placed at a predetermined position in order to increase positioning accuracy.

  In the work cycle shown in FIG. 5, since the operation of twisting the arm (the operation of driving the fourth axis (J4)) is not required, the fourth axis (J4) is not operating. In other words, an execution command (an operation command to be described later) for driving the motor 20 during the work cycle is not output to the drive unit 23 provided corresponding to the fourth axis (J4). Hereinafter, in the present embodiment, the drive unit 23 that does not operate during the work cycle, such as the drive unit 23 provided corresponding to the fourth axis (J4), is referred to as a non-operational axis for convenience, and the non-operational state is referred to. This is referred to as a non-operating state.

  Now, when the work cycle is repeatedly executed, the non-operating shaft is configured so that the internal teeth 30 of the rigid internal gear 31 and the external teeth of the flexible external gear 33 are shown in FIGS. 6 (a) to 6 (d). 32 may be in direct contact. Specifically, the lubricating oil W filled between the inner teeth 30 and the outer teeth 32 is normally diffused as shown in FIG. 6A, but the non-operating state continues. The lubricating oil W gradually becomes close to solid. When the work cycle is repeatedly executed in this state, that is, when vibration from the other drive unit 23 or the robot 2 itself is transmitted to the non-operation axis, as shown in FIG. Lubricating oil W is partially missing with a size of about a size, and a missing region R is formed. FIG. 6B shows the state of the missing region R at the beginning of the occurrence.

  When the work cycle is repeatedly executed in this state, the missing region R gradually expands as shown in FIG. When the missing region R becomes larger in this way, the inner teeth 30 and the outer teeth 32 come into direct contact. Then, when the work cycle is repeatedly executed and vibration is transmitted, the inner teeth 30 and the outer teeth 32 repeat contact, and as a result, as shown in FIG. Damaged sites K such as chipping are formed. In this state, since there is a damaged portion K, for example, when the work cycle is changed and the non-operating shaft is driven, it does not operate normally and a failure occurs.

As described above, in the articulated robot 2, the work cycle may be repeatedly executed in a state where the specific drive unit 23 does not operate at all, and since it is not operated, the useful life is not affected. In the driving unit 23 which is considered to be, a phenomenon that the service life is warped and decreases may occur. This phenomenon is a problem peculiar to the articulated robot 2 in which the drive shaft has a redundancy with respect to the work content.
Accordingly, the teaching pendant 4 traces the operation of the actual robot 2 and copes with the above-described problem by presenting a drive unit 23 that may fail, that is, a non-operation axis to the user in advance. .

Next, the operation of the teaching pendant 4 will be described together with the processing flow shown in FIG. In the present embodiment, since the fourth axis (J4) is assumed as the non-operation axis, the fourth axis (J4) (described as “fourth axis” in FIG. 7) will be described. The following processing is executed by each of the above-described units 44 to 48, but the teaching pendant 4 will be mainly described for simplification of description.
As shown in FIG. 7, the teaching pendant 4 determines whether or not its own operation mode is a check operation for tracing the operation of the robot 2 (S1), and when it is not a check operation (S1: NO), The process is terminated as it is.

  On the other hand, the teaching pendant 4 sets F to 0 when the operation mode is a check operation (S1: YES) (S2). Here, F is a flag indicating whether or not the non-operational axis (the fourth axis (J4) in the present embodiment) is operated, and is reset to 0 at the start of the check operation, and the fourth axis is operated. It is set to 1 when it is determined. Then, it is determined whether or not the execution instruction to be traced is an operation instruction (operation instruction for driving the drive unit 23) (S3). If the execution instruction is not an operation instruction (S3: NO), the process proceeds to step S7. . Then, it is determined whether or not one cycle (one work cycle) has been completed (S7). If it has not been completed, the next line (next execution instruction) is executed (S9), and the process proceeds to step S3. To do. That is, the teaching pendant 4 repeatedly analyzes the execution command in step S3 until the work cycle is completed.

  When the teaching pendant 4 determines in step S3 that the execution command is an operation command (S3: YES), the teaching pendant 4 determines whether or not the fourth axis operates (S4). (S4: YES), after setting F to 1 (S5), the process proceeds to step S6. This indicates that the fourth axis operates during this work cycle. On the other hand, when the fourth axis does not operate (S4: NO), step S5 is omitted, and it is determined whether or not the startup complement method in the operation is a PTP operation, that is, whether or not it is a PTP operation. (S6). If it is not the PTP operation (S6: NO), the process proceeds to step S7 to determine whether one cycle is completed as described above.

  On the other hand, when the activation complement method is PTP (S6: YES), the teaching pendant 4 calculates a trajectory (P) for moving the fourth axis in the PTP operation (S10). Here, the trajectory (P) is an operation of rotating the fourth axis in the + direction. Subsequently, the execution line of the program, the state of the end effector IO (indicates whether or not the work is held, indicates a state where IO = OFF is not held), the operation time of the PTP operation, and the rotation of the fourth axis The direction is stored in the PTP operation list (see M3 in FIG. 8 to be described later. Operation history of PTP operation in the work cycle).

As described above, the teaching pendant 4 repeats the process of storing the operation of the arm during the work cycle as the operation history together with the movement mode and operation time of the arm until one cycle is completed. Even if F = 1 in step S4, that is, when the fourth axis moves, if it is a PTP operation (S5: YES), the process proceeds to step S9 by measuring the operating time of the PTP operation in advance. This is for determining whether or not the PTP operation is the output target of the auxiliary execution instruction in the future work cycle.
When the teaching pendant 4 determines that one cycle has been completed (S7: YES), it determines whether F = 0 (S8). If F = 0 is not satisfied (S8: NO), the fourth axis is operating, and the process is terminated.

  On the other hand, if the teaching pendant 4 is F = 0 (S8: YES), since the fourth axis is not operating, the PTP operation list is rearranged in the longest order (S12), PTP The operation list is rearranged in the order of end effector IO = OFF (that is, the order in which the workpiece is not held) (S13), and the user is notified that the fourth axis is not operating (S14). Specifically, the teaching pendant 4 notifies (presents) the user by displaying a PTP operation list on the display unit 4a as shown in FIG. 8 (S15). As shown in FIG. 8, the display unit 4a displays, as a trace screen, a display area M1 that displays a model of the robot 2 to be simulated, a display area M2 that shows a non-motion axis, and a PTP action list. A display area M3 is provided. In the display area M1, an indication of the modeled appearance of the robot 2, the position of each axis, and the non-operating axis (in the case of FIG. 8, the fourth axis (J4) is displayed in reverse video, Indicating the motion axis). The display area M2 indicates that the non-operation axis is the fourth axis (J4).

  In the display area M3, the “movement mode” which is the movement mode of the arm, the “order” indicating which PTP operation is the PTP operation in the work cycle, and the operation time of the PTP operation in milliseconds “Operation time”, and “Work holding” indicating whether or not the work is held in the PTP operation (non-holding = not holding, holding = showing holding state) are shown. . In the display area M3, the operation history of the PTP operation is displayed in the order of the long operation time and the order of whether or not the workpiece is held among the plurality of PTP operations executed during the work cycle. Yes. More specifically, the PTP operation with the longest operation time is given priority and displayed at the top of the list, while the PTP operation that holds the work even if the same time is long (PTP operation of “order” = 3) Is displayed at a lower position in the list than a PTP operation that has a short operation time and does not hold a workpiece (PTP operation of “order” = 7).

  When the PTP operation list is displayed in this way, the teaching pendant 4 accepts an operation by the user from the switches 4b, and if there is an operation instruction for the fourth axis (S16: YES), specifically, as shown in FIG. If the PTP operation for operating the fourth axis is selected (in FIG. 8, the state in which the PTP operation of “order” = 4 is selected is schematically shown by hatching), the PTP of the designated row The operation is changed so that the fourth axis operates (S17). As a result, in the case of FIG. 8, the fourth axis (J4) operates in the PTP operation of “order” = 4. If no operation instruction is given by the user (S16: NO), the process ends.

  In this way, the teaching pendant 4 traces the execution command given to the robot 2 during the work cycle, stores the operation time and whether or not the workpiece is held for each PTP operation as an operation history. It is determined whether an auxiliary execution command can be output in the PTP operation, and the execution line of the PTP operation is changed in accordance with a user operation input (the auxiliary execution command is added to the execution command).

  In this way, a non-motion axis that does not operate in the original (that is, the user initially set) work cycle is presented, and an auxiliary execution command can be added according to the user's operation. It is possible to change the work cycle so as to operate the four axes (J4)), and the missing region R generated when vibration is transmitted in the non-operating state as described above is initially missing. Lubricating oil W can be replenished to region R, and the occurrence of missing region R itself can be suppressed by driving the non-operation shaft to diffuse lubricating oil W in advance.

According to this embodiment described above, the following effects can be obtained.
The teaching pendant 4 as a robot controller analyzes an execution command given to the robot 2 and stores a series of execution command analysis results for executing a predetermined work cycle as an operation history in the work cycle. Then, based on the motion history, it is determined whether or not there is a non-motion axis that is the drive unit 23 that is not operating during the work cycle among the axes of the robot, and presents to the user that there is a non-motion axis To do. Thus, when the robot 2 is actually installed, the operation is traced to indicate to the user that there is a drive unit 23 that does not operate during the work cycle. Therefore, it is possible to take measures such as adding an execution command for driving the non-operating axis to the drive unit 23 that may cause a failure as described above. Can be suppressed.

  In addition, since the robot 2 is actually installed and whether or not the non-operating axis exists is confirmed while checking the actual trajectory of the arm, the possibility of colliding with the peripheral equipment can be prevented. At this time, it is not easy for the user to determine whether or not there is a non-operating axis by visually observing the operation of the robot 2, but since the non-operating axis is displayed on the display unit 4a, the non-operating axis can be easily determined. It can be confirmed whether or not it exists.

  It is determined whether the movement mode when moving the arm between preset teaching points (P1 to P4) is the PTP operation or the CP operation, and the period during which the arm is performing the PTP operation is not operated. It is presented as an operable period during which the axis can be operated. At this time, the period in which the PTP operation is performed is set as the operable period based on the support of the analysis result of the inventor as described above. As a result, the lubricating oil W can be diffused into the missing region R at the beginning of the occurrence, the expansion of the missing region R can be suppressed, and the lubricating oil W can be diffused by operating the non-operation shaft. Therefore, the occurrence of the missing region R itself can be suppressed. In addition, as described above, since the operation of the non-operation axis is an operation that can be performed during the PTP operation, the operation is completed during the PTP operation, so that the tact time is not affected and the production efficiency is improved. The possibility of a decrease can be suppressed.

In addition, by presenting the operable period to the user, the user can immediately determine which PTP operation should operate the non-operation axis, so that convenience is improved.
When there are a plurality of PTP operations in the work cycle, the PTP operation with the longest operation time is presented with priority. If the operation time of the PTP operation is long, even if the non-operation axis is operated, it can be surely returned to its original position, so that it does not significantly affect the trajectory of the arm and is less active within the operation time. The axis can be moved greatly, and the generation and expansion of the missing region R can be further suppressed.
At this time, since the period in which it is determined that the workpiece is not transferred is preferentially presented, even if a non-motion axis that is not assumed in the original (initial) work cycle is operated, the operation This prevents the work from colliding with peripheral equipment.

(Second Embodiment)
In the first embodiment, a 6-axis vertical articulated robot is exemplified, but the present invention may be applied to a 4-axis horizontal articulated robot as shown in FIG. In addition, the same code | symbol is attached | subjected to the site | part substantially common with 1st Embodiment, and detailed description is abbreviate | omitted.

  As shown in FIG. 11, the robot 62 constituting the robot system 61 can rotate around a base 63 fixed to the installation surface and a first axis (J61) having an axis in the Z direction on the base 63. A first arm 64 coupled to the first arm 64, a second arm 65 coupled to the tip of the first arm 64 so as to be rotatable about a second axis (J62) having an axis in the Z direction, and a second arm A shaft 66 is provided at the tip end portion of the shaft 65 so as to be movable up and down (arrow A direction) and rotatable about a third axis (J63) having an axis center in the Z direction. A flange 67 for attaching a tool or the like is positioned and attached to the front end (lower end) of the shaft 66 so as to be detachable.

  Even in such a configuration, by performing the same processing as in FIG. 6 of the first embodiment, it is determined whether or not the drive unit 23 provided corresponding to the plurality of axes is a non-operation axis. By outputting the auxiliary execution instruction during the PTP operation during the work cycle, the same effect as in the first embodiment can be obtained, such as the expansion of the missing region R and the occurrence itself can be suppressed.

(Other embodiments)
The present invention is not limited to the above-described embodiments, and the following modifications or expansions are possible.
The robot control device may be constituted by the teaching pendant 4 alone or the combination of the controller 3 and the teaching pendant 4 as described above. However, the controller 3 has a display function and an operation input function, and the controller 3 alone is used. A robot control device may be configured. Further, the shape of the teaching pendant 4 is not limited to that exemplified in each embodiment. In each embodiment, the teaching pendant 4 is provided as a dedicated terminal. However, for example, a so-called laptop computer may be employed and teaching may be performed by executing a teaching application. . That is, the robot control device can employ a configuration other than that exemplified in each embodiment.

In each embodiment, the wave gear device is exemplified as the gear mechanism. However, the present invention can be applied to other configurations as long as a gear is used.
In the first embodiment, the fourth axis (J4) is the target. However, by performing the same processing as in FIG. 9 for the other axes, all of the plurality of driving units 23 provided in the robot 2 are processed. On the other hand, when it is determined that the axis is a non-motion axis, it can be operated, and the same effect as in the first embodiment can be obtained.

  Of course, the same processing as in FIG. 7 is performed individually for all axes, and auxiliary execution instructions are individually output to all the drive units 23 determined to be non-operating axes during the same work cycle. May be. In this case, when a plurality of non-motion axes are specified, an auxiliary execution command may be output during the same PTP operation, or an auxiliary execution command may be output in different PTP operations.

  In each embodiment, an auxiliary execution command for moving one or more teeth of the gear mechanism is output. However, the amount of movement is adjusted according to the operation time of the operable period for outputting the auxiliary execution command. You may do it. For example, the movement amount may be increased if the operation time of the operable period is long. This is because if the operation time is long, it can be returned to the original meshing position by the end of the operable period. In this way, the diffusion of the lubricating oil W can be further promoted and can be reliably prevented from the occurrence of the missing region R. In this case, in order to reduce the influence on the trajectory of the arm, it is desirable to select the PTP operation as the operable period.

  In each embodiment, the lubricating oil W is exemplified as having a property close to an individual in a non-operating state. However, the lubricating oil W may always have a liquid property. In this case, since it may be considered that the part where the amount of the lubricating oil W is reduced, that is, the part where the lubricating oil W is cut out corresponds to the missing region R, the same processing as in FIG. The effect of can be obtained.

In the first embodiment, a 6-axis robot is illustrated, and in the second embodiment, a 4-axis robot is exemplified. However, the present invention can also be applied to a robot having a different number of axes such as a 7-axis robot.
In the first embodiment, the trajectory (P) is calculated during the PTP operation, but a trajectory (Q) that rotates in reverse to the trajectory (P) may be calculated. This is a candidate for an operable period without colliding if it is rotated in the trajectory (Q), even if it is a PTP operation that does not reach the operable period by colliding with peripheral equipment when the arm is rotated in the trajectory (P). This is because there is a possibility of becoming. Further, both the trajectory (P) and the trajectory (Q) may be calculated. If a plurality of trajectories are calculated in this way, the options for the operable period can be increased.

  In the drawings, 2 is a robot, 3 is a controller (robot control device), 4 is a teaching pendant (robot control device), 4a is a display unit (presentation means), 4b is switches (operation input means), and 44 is a command analysis unit. (Command analysis means), 45 is an operation history storage section (operation history storage means), 46 is a movement mode specification section (movement mode specification means), 47 is a non-motion axis determination section (non-motion axis determination means), and 48 is auxiliary Command adding part (auxiliary command adding means), 6 shoulder (arm), 7 lower arm (arm), 8 first upper arm (arm), 9 second upper arm (arm), 10 wrist (arm) ), 61 is a robot system, 62 is a robot, 64 is a first arm (arm), 65 is a second arm (arm), 66 is a shaft (arm), and J1 to J6 and J61 to J64 are axes.

Claims (5)

A robot controller for controlling an articulated robot having a plurality of arms,
Command analysis means for analyzing an execution command given to the robot;
An operation history storage means for storing an analysis result of a series of the execution instructions for executing a predetermined work cycle as an operation history of the robot in the work cycle;
Non-operation axis determination means for determining whether or not there is a non-operation axis that is not operating during the work cycle among the axes of the robot based on the operation history;
Presenting means for presenting to the user that the non-motion axis exists;
A robot control device comprising: During the work cycle, when the arm is moved between preset teaching points, the movement mode of the arm is relative to the work movement or the movement speed of the arm with a relative emphasis on the movement trajectory of the arm. Further comprising a movement mode specifying means for specifying which of the movement movements emphasized on
The robot control apparatus according to claim 1, wherein the presenting unit further presents a period during which the moving operation is performed as an operable period during which the non-motion axis can be operated. The movement mode specifying means further specifies whether or not the robot is in a transfer state in which the workpiece is transferred by the robot,
The robot control apparatus according to claim 2, wherein the presenting unit further presents the period that is not in the transfer state as the operable period in the operable period.   4. The robot control apparatus according to claim 2, wherein the presenting means presents a priority in a long period when there are a plurality of the operable periods in the work cycle. An operation input means for inputting a user operation;
An auxiliary command adding means for adding an auxiliary execution command for operating the non-motion axis during the operable period in response to an operation by a user;
The robot control device according to claim 2, further comprising:

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