JP5983170B2 - Robot simulation device - Google Patents

Description

  The present invention relates to a robot simulation apparatus that models an articulated robot having a plurality of arms and simulates the operation of the robot.

  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 drive unit that may fail early when simulating an articulated robot including a plurality of drive units. The object is to provide a robot simulation device.

  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 not moving during the work cycle among the axes of the robot, and the user is notified that there is a non-motion axis.

  Thus, before the robot is actually installed and the work cycle is executed, 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

  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.

  According to the fifth aspect of the present invention, the work is performed in a state in which the movable range of the arm is set, a virtual object is arranged within the movable range, and an auxiliary execution command for operating the non-motion axis is added during the operable period. When the cycle is executed, it is determined whether or not the arm trajectory collides with the object, and the determination result is presented. The object corresponds to peripheral equipment in an actual work environment. Thereby, it is possible to confirm the operation when the auxiliary execution command is executed on the simulation device of the robot. In this case, if a hand (referred to as an end effector), a work held by the hand, or peripheral equipment is placed as an object, can the non-motion axis be moved while reproducing the actual operating environment? It can be determined whether or not.

The figure which shows schematically the structure of the robot made into object by 1st Embodiment of this invention. Diagram showing gear mechanism The figure which shows an example of CP operation | movement and PTP operation | movement typically FIG. 4 is an enlarged view of the IV region in FIG. 2, schematically showing the transition of the lubricant missing region. Diagram showing schematic configuration of simulation device A diagram schematically showing the electrical configuration of the simulation apparatus Figure 1 showing an example of a simulation screen of the simulation apparatus Figure 2 showing an example of the simulation screen of the simulation apparatus Diagram showing the processing flow of the simulation device The figure which shows an example of the presentation screen of a simulation apparatus 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.
First, the target robot and the mechanism of failure will be described with reference to FIGS. As shown in FIG. 1, a general industrial robot system 1 includes an articulated robot 2, a controller 3 for controlling the robot 2, and a teaching pendant 4 connected to the controller 3.

  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. Corresponding to each axis (J1 to J6) provided in the robot 2, a motor, an encoder for detecting the rotational position of the motor, a speed reducer 22 for reducing the output of the motor (see FIG. 2), etc. A configured drive unit is provided.

  The controller 3 includes a computer having a CPU (not shown), a drive circuit for operating the drive unit of the robot 2, and the like, and controls the robot 2 based on a computer program. Specifically, as is well known, the controller 3 drives the motor by outputting various commands for causing the robot 2 to repeatedly execute a predetermined work cycle, and the motor detected by the encoder. The robot 2 is controlled by performing feedback control based on the rotational position.

  As shown in FIG. 2, the speed reducer 22 constituting the drive unit of the robot 2 employs a so-called wave gear device in the present embodiment. The speed reducer 22 is an annular rigid internal gear 31 having internal teeth 30 formed on the inner peripheral surface thereof, a flexible external tooth having an external tooth 32 provided concentrically inside the rigid internal gear 31. A gear 33 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. 4) 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.

  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, 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 is determined. Move 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 flexible external gear 33 serves as an output shaft, and the reduced rotation of the motor is taken out.

  As shown in FIG. 1, the teaching pendant 4 is formed in, for example, a thin, substantially rectangular box shape, and is generally large enough to be carried or carried by the user. The teaching pendant 4 is provided with various key switches and a touch panel, and the user performs various input operations using the key switches and the touch panel. The teaching pendant 4 is connected to the controller 3 via a cable, and performs high-speed data transfer with the controller 3 via a communication interface. The teaching pendant 4 is input by operating a key switch or the like. Information such as operation signals is transmitted from the teaching pendant 4 to the controller 3.

Here, a work cycle executed by the robot 2 will be described.
As shown in FIG. 3, the work cycle is a work in which, for example, the transfer of a workpiece is repeatedly performed via predetermined teaching points P1 to P4. For example, in FIG. 3, 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. 3, 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 during the work cycle is not output to the drive unit provided corresponding to the fourth axis (j4). Hereinafter, in this embodiment, a drive unit that does not operate during a work cycle, such as a drive unit provided corresponding to the fourth axis (J4), is referred to as a non-operation axis for convenience, and a non-operation state is non-operation. This is called a 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. 4 (a) to 4 (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. 4 (a), 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 another drive unit or the robot 2 itself is transmitted to the non-operation shaft, as shown in FIG. Lubricating oil W is partially missing at a size of 3 to form a missing region R. FIG. 4B 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 a specific driving unit does not operate at all, and since it does not operate, originally there is no influence on the service life. In the drive part which is considered, the 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.
Therefore, at the stage of simulating the operation of the robot 2, that is, before installing the actual robot 2, the above-mentioned problem can be addressed by presenting a drive unit that may fail to the user in advance. Yes.

  As shown in FIG. 5, the simulation apparatus 40 includes a computer 41, a monitor 42, a keyboard 43, and a mouse 44. As shown in FIG. 6, the computer 41 includes a CPU 45, a ROM 46, a RAM 47, an HDD 48, and an input / output unit 49, and the entire simulation apparatus 40 is controlled by a program stored in the ROM 46, the HDD 48, or the like as storage means. Control. The HDD 48 also stores programs such as an application (hereinafter referred to as an application) for executing a simulation of the robot 2. The simulation apparatus 40 models the articulated robot 2 having a plurality of arms as described above, operates the modeled data in a virtual space, and simulates the operation of the robot 2.

  The monitor 42 employs, for example, a liquid crystal display, and displays an application execution screen, an execution result (simulation result), and the like. Specifically, as described later, the monitor 42 has a non-operating axis among the arms of the robot 2, whether the arm operation is a moving operation, and whether a work is held. App execution such as whether the arm collides with peripheral equipment (K1, K2, see FIGS. 7 and 8), and an operable period during which the arm can be operated during the work cycle The result is displayed (presented to the user). The monitor 42 constitutes the presenting means described in the claims. The keyboard 43 and the mouse 44 function as operation input means capable of inputting a user operation on the simulation apparatus 40 and the application.

  In addition, the simulation apparatus 40 includes a command analysis unit 50, an operation history storage unit 51, a movement mode identification unit 52, a non-motion axis determination unit 53, an auxiliary command addition unit 54, a movable range setting unit 55, a collision determination unit 56, an object arrangement A portion 57 is provided. In the present embodiment, these units 50 to 57 are realized by software by a program executed by the CPU 45. Each unit 50 to 57 may be realized by hardware.

The command analysis unit 50 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 for driving the arm and control commands for determining the branch condition. The instruction analysis unit 50 constitutes instruction analysis means described in the claims.
The operation history storage unit 51 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 51 constitutes the operation history storage described in the claims.

When the movement mode specifying unit 52 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 52 specifies whether or not the robot 2 is in a transfer state in which a work is held (transferred). The movement mode identification unit 52 constitutes a movement mode identification unit described in the claims.
Based on the motion history stored in the motion history storage unit 51, the non-motion axis determination unit 53 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 53 constitutes non-operation axis determination means described in the claims.

  The auxiliary command adding unit 54 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 the case of a robot having 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 is rotated once (the motor By rotating the output shaft once (not turning the gear mechanism of FIG. 2 once), the tip of the hand moves only about 13 mm (2π ÷ 100 × 200 = 4π) at maximum. The auxiliary command adding unit 54 constitutes auxiliary command adding means described in the claims.

The movable range setting unit 55 sets a movable range in which the arm can be operated in the virtual space. The movable range setting unit 55 constitutes a movable range setting means described in the claims.
The collision determination unit 56 determines whether or not the arm trajectory collides with an object to be described later when the simulation is executed with the auxiliary execution command added. The collision determination means constitutes the collision determination means described in the claims.

  The object placement unit 57 places a virtual object corresponding to, for example, peripheral equipment in an actual work environment within the movable range V (see FIGS. 7 and 8) set by the movable range setting unit 55. In addition, as an object to be arranged, not only an object such as a peripheral facility but also a range such as an entry prohibition area can be set. The object placement unit 57 constitutes object placement means described in the claims.

  As shown in FIGS. 7 and 8, the simulation device 40 having such a configuration sets peripheral facilities K1 and K2 as objects and a movable range V for the robot 2 modeled on the monitor 42. 7 shows an XY plan view in the virtual space, and FIG. 8 shows a YZ plan view in the virtual space. 7 and 8, the hand and the work are not shown, but the above-described collision determination unit 56 can determine not only the arm but also the collision between the hand and the work held by the hand and the object.

  Next, the operation of the simulation apparatus 40 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 (described as “fourth axis” in FIG. 9) will be described. In addition, the following processing is executed by each of the above-described units 50 to 57, but for simplification of description, the simulation device 40 will be mainly described.

The meanings of the variables used in the flowchart of FIG. 9 are as follows.
F: A flag indicating whether or not the fourth axis (J4) has operated. It is reset to 0 at the start of the work cycle, and is set to 1 when the fourth axis operates.
P: An operation locus that moves (rotates) the fourth axis to the + side.
Q: An operation locus for moving (rotating) the fourth axis to the-side.

  When the simulation of the work cycle is started as shown in FIG. 9 after the modeling of the robot 2 and the placement of the objects (K1, K2) are completed, the simulation apparatus 40 sets F to 0 (S1) and executes it. It is determined whether or not the command is an operation command (operation command for driving the drive unit) (S2). If the command is not an operation command (S2: NO), the process proceeds to step S6. Then, it is determined whether or not one cycle (one work cycle) is completed (S6). If not completed, the next line (next execution instruction) is executed (S8), and the process proceeds to step S2. . That is, the simulation device 40 repeatedly analyzes the execution instruction in step S2 until the work cycle is completed.

  When the simulation apparatus 40 determines in step S2 that the execution instruction is an operation instruction (S2: YES), it determines whether or not the fourth axis operates (S3). S3: YES), F is set to 1 (S4). This indicates that the fourth axis operates during this work cycle. On the other hand, if the fourth axis does not operate (S3: NO), step S4 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. (S5). If it is not a PTP operation (S5: NO), the process proceeds to step S6 to determine whether one cycle is completed as described above.

  On the other hand, when the startup complement method is PTP (S5: YES), the simulation apparatus 40 calculates a trajectory (P) for moving the fourth axis in the PTP operation (S9), and the trajectory (P ) To determine whether or not the calculated trajectory (P) collides with an obstacle (object) when the arm is moved when it is operated (when an operation command is added to move in the trajectory (P)). (S10). Here, the collision between the arm, the hand and the work and the object is determined. If it is determined that the trajectory (P) does not collide (S10: YES), the process proceeds to step S11. On the other hand, if it is determined that the trajectory (P) collides (S10: NO), a trajectory (Q) that moves the fourth axis in the opposite direction to the trajectory (P) is calculated (S12), and the trajectory (Q) is determined to be an obstacle. It is determined whether or not to operate (S13). If the trajectory (Q) does not collide with an obstacle (S13: YES), the process proceeds to step S11. If it is determined that both the trajectory (P) and the trajectory (Q) collide (S10: NO and S13 NO), if the arm is operated during the current operation, a collision occurs. Transition.

  Thus, the simulation apparatus 40 determines whether or not the fourth axis can be operated if the execution instruction is an operation instruction and the operation is a PTP operation. 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 simulation apparatus 40 determines that the fourth axis operation is possible in either the trajectory (P) or the trajectory (Q) (S10: YES or S13: YES), the execution line of the program, the end effector IO state (whether or not the workpiece is held, IO = OFF indicates that the workpiece is not held), the operation time of the PTP operation, and the rotation direction (trajectory (P) or trajectory (Q Is stored in the PTP operation list (see M3 in FIG. 10 described later. Operation history of PTP operation during work cycle). As described above, the simulation device 40 stores the movement of the arm during the work cycle as the movement history together with the movement mode and movement time of the arm.

If the simulation apparatus 40 determines in step S6 that one cycle has been completed (S6: YES), it determines whether F = 0 (S7). If F = 0 is not satisfied (S7: NO), the fourth axis is operating, and the process is terminated.
In contrast, when F = 0 (S7: YES), the fourth axis does not operate, so the PTP operation list is rearranged in the longest order (S14), 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) (S15), and the user is notified that the fourth axis is not operating (S16). Specifically, the simulation apparatus 40 notifies (presents) the user by displaying a PTP operation list on the monitor 42 as shown in FIG. 10 (S17).

  As shown in FIG. 10, the monitor 42 has a display area M1 for displaying the model of the robot 2 to be simulated, a display area M2 for indicating a non-operation axis, and a PTP operation as a display screen for the execution result of the application. A display area M3 for displaying a list is provided. In the display area M1, the modeled appearance of the robot 2, the position of each axis, and the non-operating axis are displayed (in the case of FIG. 10, 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” indicating, “work holding” indicating whether or not the workpiece is held in the PTP operation (non-holding = not holding, holding = showing holding state), and whether to collide “Collision” (○ indicates a state of no collision) is 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 simulation apparatus 40 accepts a user operation from the keyboard 43 or the mouse 44, and if there is an operation instruction for the fourth axis (S18: YES), specifically, FIG. As shown, if the PTP operation for operating the fourth axis is selected (in FIG. 10, the state in which the PTP operation of “order” = 4 is selected is schematically shown by hatching), the designated row The PTP operation is changed so that the fourth axis operates (S19). Thus, in the case of FIG. 10, the fourth axis (J4) operates in the PTP operation of “order” = 4. If no operation instruction is given by the user (S18: NO), the process is terminated.

  As described above, the simulation device 40 stores, as an operation history, the operation time and whether or not the workpiece is held for each PTP operation in the work cycle, and can output an auxiliary execution instruction at which PTP operation. And the execution line of the PTP operation is changed according to a user operation input (an auxiliary execution instruction is added to the execution instruction).

  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 execution instruction given to the robot 2 is analyzed, 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, and each of the robots is analyzed based on the operation history. It is determined whether or not there is a non-operating axis that is not operating during the work cycle, and the user is notified that there is a non-operating axis. Thereby, before actually installing the robot 2 and executing the work cycle, that is, at the stage of simulation for confirming the operation of the robot 2, it can be shown to the user. 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

  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 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 Therefore, there is no problem that the work collides with the peripheral equipment (K1, K2).

  A work cycle in which the arm movable range V is set, virtual objects (K1, K2) are arranged in the movable range V, and an auxiliary execution command for operating the non-motion axis is added during the operable period. Is executed, it is determined whether or not the arm trajectory (trajectory (P) or trajectory (Q)) collides with the object (K1, K2), and the determination result is presented as "Collision" in FIG. To do. Thereby, it is possible to confirm the operation when the auxiliary execution command is executed at the simulation stage of the robot 2. In addition, since peripheral equipment and the like are arranged as objects, it is possible to determine whether or not the motion of the non-motion axis is possible after reproducing the actual motion environment.

  In this embodiment, since an auxiliary execution command can be added, it is possible to take measures such as outputting an auxiliary execution command to the non-operation axis for each work cycle. Thereby, a drive part is driven for every work cycle, and lubricating oil W spreads. In this case, since the work cycle is generally considered to be about one minute, the non-operating shaft operates before the missing region R occurs, so that the occurrence of the missing region R can be prevented more reliably.

(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 driving unit provided corresponding to the plurality of axes is a non-operating axis. By outputting the auxiliary execution instruction during the PTP operation in the cycle, it is possible to obtain the same effect as that of the first embodiment, 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.
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 targeted. However, the same processing as in FIG. 9 is performed for the other axes, so that all of the plurality of driving units provided in the robot 2 are performed. If it is determined that the axis is a non-operation 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. 9 is performed individually for all axes, and auxiliary execution commands are individually output during the same work cycle to all drive units determined to be non-operating axes. Also good. 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 drawings, 2 is a robot, 6 is a shoulder (arm), 7 is a lower arm (arm), 8 is a first upper arm (arm), 9 is a second upper arm (arm), 10 is a wrist (arm), 40 Is a simulation device, 41 is a monitor (presentation means), 50 is a command analysis section (command analysis means), 51 is an operation history storage section (operation history storage means), 52 is a movement mode specification section (movement mode specification means), 53 Is a non-motion axis determination unit (non-motion axis determination unit), 54 is an auxiliary command addition unit (auxiliary command addition unit), 55 is a movable range setting unit (movable range setting unit), and 56 is a collision determination unit (collision determination unit). , 57 is an object placement unit (object placement means), 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), J1 to J6, J 1~J64 the axis, K1, K2 objects, V is showing a movable range.

Claims (5)

A robot simulation device that models an articulated robot having a plurality of arms and simulates the operation of the robot,
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 simulation apparatus 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
2. The robot simulation apparatus according to claim 1, wherein the presenting unit further presents a period during which the moving motion is performed as an operable period during which the non-motion axis can be moved. 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,
3. The robot simulation 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 simulation apparatus according to claim 2, wherein the presenting unit preferentially presents a long period when there are a plurality of operable periods in the work cycle. 5. A movable range setting means for setting a movable range of the arm;
Object placement means for placing a virtual object within the movable range;
An auxiliary command adding means for adding an auxiliary execution command for operating the non-motion axis during the operable period;
Collision determination means for determining whether or not the trajectory of the arm collides with the virtual object when the work cycle is executed with the auxiliary execution command added;
5. The robot simulation apparatus according to claim 2, wherein the presenting unit further presents a determination result by the collision determination unit.

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