JP2006099310A - Robot simulation apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that teaching data has to be corrected so as to obtain a set operating time since the operating time for operating an actual robot is sometimes different from the operating time prepared by simulating off-line teaching data. <P>SOLUTION: A servo simulation part considering servo calculation and robot dynamics is connected to a conventional simulator (motion simulation part), and then, a simulation control part performs controlling by synchronizing the whole simulation. The positioning completion signal of the servo simulation part is processed by the motion simulation part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a robot simulation apparatus, and more particularly, to a robot simulation apparatus and method for measuring operation verification and time required for operation by off-line teaching, and supporting robot mechanical design, electrical design, and control design.

In the manufacturing process of industrial products, production lines have been automated using industrial robots, and robots are used in processes such as welding, parts conveyance, cutting, and assembly. When operating a robot in the manufacturing process, it is first necessary to perform a teaching operation to teach the robot to operate. A simulator is often used when teaching, and a dedicated or general-purpose robot simulator is commercially available. By using a simulator, there is an advantage that teaching can be performed without moving an actual robot or line. However, in order to maintain production efficiency at an actual manufacturing site, work time (cycle time) in each process is set, and it is necessary to teach the operation of the robot so as to be within the cycle time. For this reason, the normal robot simulator has a function for measuring the operation time of the robot, and the operation time can be measured in an arbitrary operation section by performing a simulation based on the taught data. However, if the operation time measured in the simulation is significantly different from that when the actual robot is moved, the simulation is performed by correcting the teaching data so that the actual operation time of the robot falls within the set operation time. Again, it is necessary to evaluate the operation time and the cycle time of the entire process with an actual robot. Therefore, it is desirable for the robot simulator to calculate an accurate operation time.
The cause of the error in the operation time mainly includes a servo tracking delay with respect to the operation command, a processing time delay between peripheral devices, and the like. In particular, the servo follow-up delay is dealt with by providing a servo follow-up delay time estimation function in the simulator in the conventional robot simulation apparatus (see, for example, Patent Document 1).
FIG. 6 shows an example of a conventional robot simulation apparatus. 61 is teaching data generation means for creating teaching data. Reference numeral 62 denotes an operation command generation means for generating an operation command for each axis from the teaching data for each control cycle. The motion command generating means 62 simulates the motion command generating section of an actual robot controller, and the motion command generated here is sent to the servo tracking delay estimating means 63 to perform a simulation considering the tracking delay. The result is sent to the drawing means 64 to draw a three-dimensional model of the robot. Reference numeral 65 denotes an operation time measuring means for measuring the operation time in the simulation. As described above, the conventional robot simulation apparatus enables more accurate operation time measurement by the operation command generation means simulating an actual robot controller and the servo tracking delay estimation means 63.

Japanese Patent Laying-Open No. 2004-151976 (page 5-6, FIG. 2)

However, the servo tracking delay estimation means in the conventional robot simulation device is a simple filter that does not simulate the processing contents of the actual robot controller, and according to the characteristics and models of various servo control rules. It does not consider the characteristics of robot dynamics. This is to simplify the simulation software, but because the above characteristics are not taken into account, there is a problem that it is not possible to measure an accurate operation time that matches the actual operation of the robot. was there.
The present invention has been made in view of such problems, and an object of the present invention is to provide a robot simulation apparatus and method capable of measuring an accurate operation time without complicating simulation software.

In order to solve the above problem, the present invention is configured as follows.
According to a first aspect of the present invention, there is provided a robot simulation apparatus that performs teaching and motion simulation of a robot offline, generating a motion data and generating a motion command based on the teaching data, and the motion A servo simulation unit that performs a servo calculation in response to a command, and a simulation control unit that mediates data transmission / reception between the motion simulation unit and the servo simulation unit and synchronizes the processing of both are provided.
According to a second aspect of the present invention, the simulation control unit includes general communication processing means for communicating with the motion simulation unit and the servo simulation unit, and activation and simulation execution for the motion simulation unit and the servo simulation unit. A simulation control means for instructing start / stop and an operation means for performing a simulation operation are provided.
According to a third aspect of the present invention, the motion simulation unit transmits the operation command to the servo simulation unit through communication with the simulation control unit, and receives the result of the servo calculation by the servo simulation unit. A processing unit; an operation time measuring unit for simulating the operation of the robot based on the result of the servo calculation; and a drawing unit for performing graphic drawing of the robot based on the result of the servo calculation. It is characterized by comprising.
The invention according to claim 4, wherein the motion simulation unit is configured to enable communication with the simulation control unit and set whether to perform data transmission / reception with the servo simulation unit, Servo simulation switching means for switching validity / invalidity of the servo communication processing means according to the contents is provided.
According to a fifth aspect of the present invention, the servo simulation unit receives the operation command from the motion simulation unit and transmits the result of the servo calculation to the motion simulation unit through communication with the simulation control unit. Motion communication processing means for performing the above and dynamics simulation means for performing dynamics simulation calculation of the robot.
According to a sixth aspect of the present invention, the servo simulation unit enables communication with the simulation control unit and sets whether to perform data transmission / reception with the motion simulation unit, and setting And a motion simulation switching unit that switches between valid / invalid of the motion communication processing unit according to the contents.
According to a seventh aspect of the present invention, the servo simulation unit includes a positioning completion signal generated according to a difference between a command position and a feedback position of each joint axis of the robot in the result of the servo calculation. The simulation unit generates the operation command according to the positioning completion signal.
The servo simulation unit includes a feedback position of a secondary joint angle calculated by the dynamics simulation unit in a result of the servo calculation, and the motion simulation unit includes the drawing unit. The robot is graphically drawn according to the secondary joint angle.
The invention according to claim 9 is a robot simulation method for executing teaching and motion simulation of a robot off-line, wherein the first step of generating teaching data and generating an operation command based on the teaching data is provided. The second step of performing servo calculation in response to the operation command, and the third step of mediating data transmission / reception between the first step and the second step and synchronizing the processing of both. Features.

According to the first aspect of the present invention, it is possible to measure an accurate operation time without complicating the simulation software.
According to the second aspect of the present invention, the software for motion simulation and servo simulation can be integrated and simulated, and the software of the motion simulation unit and the servo simulation unit itself is not complicated.
According to the third aspect of the present invention, detailed servo simulation data is received and the cycle time is measured according to the result, so that a more accurate operation time can be obtained.
According to the invention described in claim 4, it is possible to select whether or not to perform a detailed servo simulation. As a result, the calculation load can be reduced when rough operation time measurement is sufficient, or when time measurement is unnecessary and only operation confirmation is required.
According to the fifth aspect of the present invention, simulation can be performed with operation command data simulating an actual controller, so that a more accurate servo control simulation can be performed.
According to the invention described in claim 6, it is possible to select whether or not to perform a detailed motion simulation. This makes it possible to verify servo control by the servo simulation unit alone.
According to the seventh aspect of the invention, more accurate operation time measurement can be performed.
According to the eighth aspect of the invention, more accurate robot operation can be confirmed by drawing.
According to the ninth aspect of the present invention, it is possible to measure an accurate operation time without complicating the simulation software.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of a robot simulation apparatus according to the present invention. In the figure, reference numeral 1 denotes a motion simulation unit, which corresponds to a conventional offline teaching robot simulator. Here, off-line teaching is mainly performed to generate operation commands for each joint axis of the robot in time series, and the execution result of the simulation is drawn with three-dimensional graphics. The part where the present invention is different from Patent Document 1 is a part in which a servo simulation unit 2 and a simulation control unit 3 are added thereto. In the servo simulation unit 2, the operation command of each joint axis generated by the motion simulation unit 1 is fetched, calculation such as proportional-integral control of the position and speed according to the robot dynamics is performed, and the result is sent to the motion simulation unit 1. At this time, the simulation supervision unit 3 activates the motion simulation unit 1 and the servo simulation unit 2, controls the start / stop of the simulation, and mediates the exchange of data synchronized with each other. With such a configuration, it is possible to perform a detailed simulation in consideration of the characteristics of the servo and the robot dynamics, and it is possible to draw an operation close to an actual robot and to accurately measure the operation time. At the same time, since the motion simulation unit 1 and the servo simulation unit 2 are distributed, the software does not become complicated and each can be used independently. Therefore, the motion simulation unit 1 and the servo simulation unit 2 can be used for multiple purposes.

FIG. 2 shows a detailed configuration of the motion simulation unit 1. In the motion simulation unit 1, teaching data is first created and stored by the teaching data generation unit 11 that performs offline teaching. The operation command generation means 12 calls the teaching data and generates an operation command according to the teaching position and the operation command described therein. This motion command generation means 12 is obtained by accurately simulating the command generation part software of an actual robot controller and simulating it. The acceleration / deceleration and trajectory according to the control parameters used in the actual controller, Cartesian coordinates A position command for each joint axis is generated based on conversion from the system to the joint coordinate system (inverse kinematic calculation).
In the conventional robot simulation apparatus, the operation command generated here is drawn through the servo follow-up delay estimating means 13, and the result is drawn by the drawing means 14, or the operation time is calculated by the operation time measuring means 15.
The portion where the present invention is different from the conventional one is provided with servo simulation setting means 16, servo simulation switching means 17, and servo communication processing means 18, and the contents to be drawn by the drawing means 14 change according to the operation of this means, The operation time measured by the operation time measuring means 15 is changed.

First, the servo simulation setting means 16 sets whether to use the conventional servo follow-up delay means 13 or to perform data transmission / reception with the servo simulation section 2 through the simulation control section. Then, according to the set value, the servo simulation switching unit 17 switches to which direction the operation command of the operation command generation unit 12 is sent. Further, the servo data is received from the switched one and sent to the drawing means 14 and the operation time measuring means 15.
When the servo simulation setting unit 16 is set to communicate with the servo simulation unit 2, the servo simulation communication processing unit 18 transmits an operation command to the simulation control unit 3, and the servo control data that is the servo simulation result from the simulation control unit 3. Receive. With this configuration, you can select whether to perform detailed servo simulation or conventional simple servo tracking delay estimation. If you select detailed servo simulation, proportional integration of the actual position speed It is possible to receive a position feedback signal that closely matches the actual robot motion in consideration of control and robot dynamics. For this reason, it is possible to measure the operation time more accurately and confirm it by drawing. On the other hand, in the case where rough operation time measurement is sufficient, or in the case where time measurement is unnecessary and only operation confirmation is required, a conventional method with a relatively small calculation load can be used.

  FIG. 3 shows a detailed configuration of the servo simulation unit 2. In the present embodiment, an example using a commercially available general-purpose control system simulator “MATLAB / Simulink” (registered trademark) will be described. Servo simulation calculation means 21 is a part that performs servo calculation in accordance with an input operation command, and feedforward control and feedback control calculation software used in an actual robot controller is transplanted for simulation and modularized. It is registered on the MATLAB / Simulink model as one simulation block. Similarly, the dynamics simulation means 22 is a module that performs the dynamics calculation of the robot based on the torque command output of the servo simulation calculation means 21, and the Newton Euler method, the Lagrange method, etc. are well known as the calculation method. Then, the motor position feedback value of each joint axis is returned to the servo simulation calculation means 21 in accordance with the resolution of the encoder that detects the position of the motor of each joint axis of the robot.

In the present invention, in order to perform accurate operation time measurement in the motion simulation unit 1, the following means are additionally configured. That is, a motion communication processing unit 23 that receives an operation command from the motion simulation unit 1 through the simulation control unit 3 and performs communication for returning servo calculation data (for example, a position feedback value) of the servo simulation result to the motion simulation unit 1; Motion simulation setting means 24 for setting whether to perform data transmission / reception with the unit 1, whether to send an operation command from the motion simulation unit 1 to the servo simulation calculation unit 21 according to the value set by the motion simulation setting unit 24 Motion simulation switching means 25 for switching whether or not is provided.
If the motion simulation setting unit 24 is set to perform data transmission / reception with the motion simulation unit 1, the motion simulation communication processing unit 23 receives an operation command from the simulation control unit 3, performs servo simulation calculation, and sends the simulation command to the simulation control unit 3. Send servo calculation data.
With this configuration, the motion simulation unit 1 can obtain an accurate servo simulation result. Furthermore, it is possible to select whether to perform detailed motion simulation or to generate a command by creating a command generation block 26 on MATLAB / Simulink. When a detailed motion simulation is selected, it is generated by an actual robot controller. The same operation command as can be received. This makes it possible to perform simulations more in line with actual robot controllers, and is useful for mechanical design, electrical design, and control design of robots. When the command generation block 26 is selected, the servo control simulation can be verified by the servo simulation unit 2 alone without using the motion simulation unit 1 or the simulation control unit 3.

Here, the servo simulation calculation means 21 is a module in which the software of feedforward control and feedback control calculated by an actual robot controller is ported for simulation, but is prepared by MATLAB / Simulink. A simple simulation model in which simulation blocks are connected may be used.
Further, in the case of an industrial robot, a reduction gear is disposed between the motor and the robot arm, and a torsion angle is generally generated in the motor and the arm due to the spring characteristics of the reduction gear. Accordingly, although the motor angle (primary side angle) and the arm angle (secondary side angle) are different, the secondary side angle is set to the motion simulation unit in order to perform drawing by the drawing means 14 of the motion simulation unit 1 in FIG. It is desirable to transmit to 1. When the secondary angle is transmitted, the secondary angle data of the calculation process of the dynamics simulation means 22 is transmitted. By doing so, an operation close to that of an actual robot is drawn.
Further, in order to enable the motion simulation unit 1 to measure an accurate operation time, a positioning completion signal set in the servo simulation calculation means 21 is sent to the motion simulation unit 1 through the simulation control unit 3. The positioning completion signal is a signal that is turned on when the difference between the rotation command position of the motor of each joint axis and the feedback position is equal to or less than a set value. By detecting this signal by the operation command generation unit 12 of the motion simulation unit 1 and generating a position command, the operation time measurement unit 15 can measure the operation time more accurately.

  Here, an example is shown in which a commercially available general-purpose control system simulator “MATLAB / Simulink” is used for the servo simulation unit 1. However, the present invention is not limited to this and is configured as described above even if it is not a commercially available simulator. It only has to be.

FIG. 4 shows a detailed configuration of the simulation control unit 3. The simulation control unit controls the motion simulation unit 1 and the servo simulation unit 2 described with reference to FIGS. 2 and 3 and controls the operation unit 31 that is a man-machine interface and the simulation control unit that controls the entire simulation apparatus. 32, a general communication processing unit 33 that transmits and receives data between the motion simulation unit 1 and the servo simulation unit 2.
The simulation control unit 32 activates the motion simulation unit 1 and the servo simulation unit 2 and starts and stops simulation execution. When executing the simulation, the processing is executed at a timing synchronized with the set cycle of the operations of the motion simulation unit 1 and the servo simulation unit 2.
The general communication processing unit 33 sends commands and setting data issued by the simulation control unit 32 to the motion simulation unit 1 and the servo simulation unit 2 and receives response data and status. To the motion simulation unit, a command for reading teaching data to be executed, a command for starting the execution, a command for executing one cycle, and the like are transmitted, and data such as a target position command at the time of executing one cycle is received. In addition, a simulation start instruction, a target position command, and the like are transmitted to the servo simulation unit 2 and servo calculation data such as a position feedback value by servo simulation calculation and dynamics simulation is received.
In addition, as a method for transmitting / receiving data to / from the motion simulation unit 1 and the servo simulation unit 2 in the overall communication processing unit 33, a method using a shared memory, a method using a socket, a method using OLE (Object Linking and Embedding), etc. Various methods are conceivable. In any case, this method is well known as a method for realizing transmission / reception of data between programs executed in different processes, and an optimal method may be selected in accordance with an environment in which simulation is executed.

Next, FIG. 5 shows a data flow of an operation example of the robot simulation apparatus of the present invention. In this operation example, a shared memory is used for data transmission / reception with the servo simulation unit 2. A shared memory is a technique often used for high-speed communication between different processes on the same CPU. Here, an example is shown in which teaching data taught offline in advance is executed.
First, the simulation supervision unit 3 issues a teaching data execution instruction (S0-S1). Although not shown, the motion simulation unit 1 performs initialization when a teaching data execution instruction is received, and reads parameters, reads specified teaching data, and the like. At this time, the simulation supervision unit 3 acquires the current joint angle (current value) of the robot from the motion simulation unit 1 (S2). This current value is set in the shared memory (S3), and the servo simulation unit 2 is instructed to start simulation (S4). When receiving a simulation start instruction, the servo simulation unit 2 performs initialization such as parameter reading (not shown) and setting of the current value (S5-S7). When the servo simulation initialization is completed, the preparation for simulation execution is completed (S8), and the process proceeds to periodic execution processing.

  In the periodic execution process, first, the simulation supervision unit 3 issues a one-cycle execution instruction to the motion simulation unit 1 (S9). As a response to this instruction, the motion simulation unit 1 returns a target position command after one cycle (S10). Next, the simulation control unit 3 sets the target position command in the shared memory in order to pass the target position command to the servo simulation unit 2 (S11). The servo simulation unit 2 acquires a target position command from the shared memory (S12-S13) and performs servo simulation calculation. The resulting secondary joint angle is set in the shared memory (S14), and the simulation supervisor 3 acquires the data (S15-S16). When data is exchanged using such a shared memory, data is not read or written at the same time using a semaphore. Thereafter, the simulation supervision unit 3 sends the secondary side joint angle to the motion simulation unit together with a drawing update instruction (S17), and the robot joint 3D graphics data is read according to the secondary side joint angle data read by the motion simulation unit 1. Update. The above is the process for one period of the period execution process, and the execution is repeated until the end of the teaching data (after S18).

  In the present invention, since the motion simulation unit and the servo simulation unit are connected by the simulation control unit, the simulation can be performed in a form closer to an actual robot system, so that not only the off-line teaching evaluation but also the mechanical design, electrical design, and control design can be performed. It can also be applied for verification purposes.

Schematic diagram of a robot simulation apparatus showing an embodiment of the present invention Detailed view of the motion simulation unit of the present invention Detailed view of servo simulation unit of the present invention Detailed view of the simulation control section of the present invention Data flow diagram of the robot simulation apparatus of the present invention Schematic diagram of a conventional robot simulation device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motion simulation part 2 Servo simulation part 3 Simulation supervision part 11 Teaching data generation means 12 Operation command generation means 13 Servo tracking delay estimation means 14 Drawing means 15 Operation time measurement means 16 Servo simulation setting means 17 Servo simulation switching means 18 Servo communication processing Means 21 Servo simulation calculation means 22 Dynamics simulation means 23 Motion communication processing means 24 Motion simulation setting means 25 Motion simulation switching means 26 Command generation block 31 Operation means 32 Simulation control means 33 General communication processing means 61 Teaching data generation means 62 Operation command generation Means 63 Servo tracking delay estimation means 64 Drawing means 65 Operating time measurement means

Claims (9)

In a robot simulation device that performs robot teaching and motion simulation offline,
A motion simulation unit that generates teaching data and generates an operation command based on the teaching data;
A servo simulation unit that performs servo calculation in accordance with the operation command;
A robot simulation apparatus comprising a simulation control unit that mediates data transmission / reception between the motion simulation unit and the servo simulation unit and synchronizes the processing of both. The simulation control unit is a general communication processing means for performing communication with the motion simulation unit and the servo simulation unit;
Simulation control means for instructing the motion simulation unit and the servo simulation unit to start and stop simulation execution;
2. The robot simulation apparatus according to claim 1, further comprising operation means for performing a simulation operation. The motion simulation unit transmits the operation command to the servo simulation unit by communication with the simulation control unit, and receives a result of the servo calculation by the servo simulation unit;
An operation time measuring means for simulating the operation of the robot based on the result of the servo calculation and measuring the required time;
The robot simulation apparatus according to claim 1, further comprising a drawing unit that performs graphic drawing of the robot based on a result of the servo calculation. The motion simulation unit enables communication with the simulation control unit and sets whether to perform data transmission / reception with the servo simulation unit;
4. The robot simulation apparatus according to claim 3, further comprising: a servo simulation switching unit that switches between valid / invalid of the servo communication processing unit according to the set contents. The servo simulation unit receives motion command from the motion simulation unit through communication with the simulation control unit, and transmits a result of the servo calculation to the motion simulation unit,
The robot simulation apparatus according to claim 1, further comprising a dynamics simulation unit that performs a dynamics simulation calculation of the robot. The servo simulation unit enables communication with the simulation control unit, and sets whether to perform data transmission / reception with the motion simulation unit, motion simulation setting means,
6. The robot simulation apparatus according to claim 5, further comprising a motion simulation switching unit that switches between valid / invalid of the motion communication processing unit according to the set contents. The servo simulation unit includes a positioning completion signal generated according to a difference between a command position and a feedback position of each joint axis of the robot in the result of the servo calculation,
The robot simulation apparatus according to claim 1, wherein the motion simulation unit generates the operation command according to the positioning completion signal. The servo simulation unit includes the feedback position of the secondary joint angle calculated by the dynamics simulation means in the result of the servo calculation,
The robot simulation apparatus according to claim 1, wherein the motion simulation unit draws a graphic of the robot according to the secondary joint angle in the drawing unit. In a robot simulation method for performing offline robot teaching and motion simulation,
A first step of generating teaching data and generating an operation command based on the teaching data;
A second step of performing servo calculation in response to the operation command;
A robot simulation method comprising a third step of mediating data transmission / reception between the first step and the second step and synchronizing the processing of both.

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