JP2013000823A - Method for generating speed command profile of industrial robot - Google Patents

Abstract

In order to generate a speed command profile that can shorten the work time of an articulated robot, a method for determining acceleration / deceleration characteristics that can flexibly cope with a wide range of motion sections and easily grasp the tendency of change. Is needed.
A first acceleration / deceleration characteristic indicating a relationship between an acceleration / deceleration time and a command speed, and a relationship between an acceleration / deceleration time and a command speed, which is increased when the command speed is the same as that of the first acceleration / deceleration characteristic. A second acceleration / deceleration characteristic with a short deceleration time is used. When it is determined that the operation section distance is a long section, the speed command profile is obtained using the first acceleration / deceleration characteristics. If it is determined to be a short section, a new acceleration / deceleration characteristic indicating the relationship between the acceleration / deceleration time and the command speed is calculated using the second acceleration / deceleration characteristics and a predetermined arithmetic expression, and the long section is determined. Using a different acceleration command profile from that in the case of using a low-pass filter, a speed command profile for a short section is generated.
[Selection] Figure 1

Description

  The present invention relates to a method for generating a speed command profile for an industrial robot such as an articulated robot.

  As a user's need for an articulated robot, which is an example of an industrial robot, it is important to shorten the work time of the articulated robot. In order to shorten the work time of an articulated robot, the relationship between the acceleration / deceleration time (acceleration time and deceleration time) that can reach a given command speed as soon as possible and the command speed (hereinafter referred to as acceleration / deceleration characteristics) ) Need to be determined. However, the determination of the optimum acceleration / deceleration characteristics is greatly affected by the motion section (movement distance) when the articulated robot performs work.

  The longer the operation section (movement distance), the longer the operation time (movement time), and the maximum speed of the speed command profile, which is the time change of the command speed, can reach the given command speed. Therefore, after considering the saturation and vibration characteristics of the motor torque, the acceleration / deceleration characteristics are focused on focusing on how much time it takes to reach the maximum speed, that is, how much the acceleration / deceleration time (acceleration time) can be shortened. Will be adjusted.

  Conversely, if the operation section (movement distance) is short, the operation time (movement time) becomes short. Therefore, it becomes difficult to reach a given command speed during the section operation time of the articulated robot. If the motion section is short and the acceleration / deceleration characteristics for the long motion section are used as they are, it is difficult to shorten the work time.

  Therefore, in order to shorten the work time, different acceleration / deceleration characteristics are required when the operation section is short and when the operation section is short and when the operation section is short. Thus, the method for determining the acceleration / deceleration characteristics varies depending on the length of the motion section. Therefore, it is difficult to determine the acceleration / deceleration characteristics that can uniquely reduce the work time in all the motion sections of the articulated robot that performs a wide variety of motions.

  Against such a background, as a conventional method, a table in which acceleration / deceleration characteristics prepared in advance are associated with operation intervals is used to optimize a predetermined operation interval based on the operation interval. There have been proposed a method using an appropriate acceleration / deceleration characteristic (for example, refer to Patent Document 1), and a method for using the acceleration / deceleration characteristic and a function together to cope with all operation sections (for example, refer to Patent Document 2).

  FIG. 8 shows an example of a method of using the optimum acceleration / deceleration characteristics for a limited operation section prepared in advance using a table in which the acceleration / deceleration characteristics and the operation sections are associated with each other. For example, for the motion section L1, the joint axis 1 uses the acceleration / deceleration characteristic A1, the joint axis 2 uses the acceleration / deceleration characteristic A2, and the joint axis 3 uses the acceleration / deceleration characteristic A3. In this method, an optimum acceleration / deceleration characteristic determined in advance according to the operation section is selected based on the information on the acceleration / deceleration characteristic and the operation section, and a speed command profile that can shorten the working time is generated.

  FIG. 9 shows an example of a technique for trying to deal with all the operation sections by using the acceleration / deceleration characteristics and the function together. By applying a specific function to a speed command profile 38 having an operation time 37 given by the acceleration / deceleration characteristics as a base, a speed command profile 40 having an ideal operation time 39 for a given operation section is generated. It shows that This method calculates the ideal operating time that can shorten the working time for a given operating section, and applies the function to the base acceleration / deceleration characteristics to obtain the ideal operating time. Generate a speed command profile with

JP-A-62-003311 Japanese Patent Laid-Open No. 2-144705

  With respect to the two methods shown in the background art, the method using only the table of the acceleration / deceleration characteristics and the operation interval described with reference to FIG. 8 can deal only with a specific operation interval in the table, and the effective range of the table Is limited, and the effect is limited.

  Further, in the method of using the acceleration / deceleration characteristics and functions described with reference to FIG. 9, the function to be used is restricted, and depending on the complexity, it is difficult to grasp the change tendency of the acceleration / deceleration characteristics, and the vibration characteristics can be controlled. It becomes difficult.

  From the above, in order to generate a speed command profile that can shorten the work time, there is a method for determining the acceleration / deceleration characteristics that can flexibly cope with a wide range of operation sections and easily grasp the tendency of change. Needed.

  In order to solve these problems, in the present invention, a method is used in which the operation sections are not subdivided, but are roughly divided within a certain range, and each operation section has an optimum acceleration / deceleration characteristic. By roughly classifying the operation sections, the number of acceleration / deceleration characteristics to be used can be minimized, and a wide range of operation sections can be handled.

  In addition, most of the multi-joint robot work movements are short-distance movements (short-distance movements) in which many axes rotate small, rather than long-distance movements (long-distance movements) in which one axis makes a large turn. Occupy. For this reason, a short section should be included in one of the roughly divided operation sections.

  Furthermore, in order to shorten the work time, it is considered that fine adjustment of acceleration / deceleration characteristics in a short section is necessary. This adjustment is performed by a function, and the function needs to be a simple arithmetic expression so that a robot operator or the like can easily grasp the change in acceleration / deceleration characteristics. Further, it is desirable to use a value that takes into consideration both the command speed and the motion section for the determination of the motion section.

  It is an object of the present invention to provide a method for generating a speed command profile for an industrial robot such as an articulated robot, which includes a procedure for determining acceleration / deceleration characteristics as described above.

  In order to solve the above-described problem, the industrial robot speed command profile generation method according to the present invention includes a rotating arm having a plurality of rotating shafts driven by a motor, and operates according to a program taught in advance. Of the first acceleration / deceleration characteristic indicating the relationship between the acceleration / deceleration time and the command speed, and the relationship between the acceleration / deceleration time and the command speed, which is compared with the first acceleration / deceleration characteristic. A second acceleration / deceleration characteristic with a short acceleration / deceleration time when the command speed is the same, with an increasing slope toward the commanded command speed until the commanded command speed is reached from a point when the speed is zero A first time which is a time required for the first time, a second time which is a time required to move the predetermined section without acceleration / deceleration at the command speed, and the first time Comparing the second time with the second time, obtaining a speed command profile based on the first characteristic if the first time is greater than the second time, and the second time And a step of obtaining a speed command profile based on the second characteristic when the time is equal to or shorter than the first time.

  In addition to the above, the method for generating a speed command profile for an industrial robot of the present invention is characterized in that the first acceleration / deceleration characteristic is that the section distance that is the distance of the section in which the articulated robot moves is the first section distance. The second acceleration / deceleration characteristic is used when the section distance is the second section distance, and the first section distance is longer than the second section distance.

  In addition to the above, the method for generating the speed command profile of the industrial robot of the present invention is not limited to the above, and when the section distance is less than the second section distance, a predetermined calculation using the second acceleration / deceleration characteristics is performed. A new acceleration / deceleration characteristic indicating the relationship between the new acceleration / deceleration time and the command speed is calculated by the equation, and the acceleration command profile different from the acceleration command profile used when the distance is the first section distance and the new acceleration / deceleration A speed command profile is obtained from the characteristics, and a speed command profile is obtained by applying a low-pass filter to the obtained speed command profile.

  As described above, according to the present invention, the working time of the industrial robot is reduced for a wide range of motion sections by using two acceleration / deceleration characteristics and a simple arithmetic expression for which the tendency of change is easily grasped. A speed command profile that can be generated can be generated.

The block diagram which shows from the setting of the command speed in the embodiment of this invention and the setting of an operation area to the production | generation of a speed command profile The figure which shows the step which determines the basic acceleration / deceleration characteristic in the long section operation | movement in embodiment of this invention The figure which shows the step which determines the basic acceleration / deceleration characteristic in the short section operation | movement in embodiment of this invention (A) The figure which shows the speed command profile in long section operation and short section operation in case step S4 in embodiment of this invention is the same (b) Long section operation in case step S4 in embodiment of this invention is the same, and Diagram showing motor torque waveform in short section operation The figure which shows the acceleration / deceleration characteristic in long section operation | movement and short section operation | movement in embodiment of this invention The figure which shows the acceleration command profile in long section operation | movement and short section operation | movement in embodiment of this invention (A) The figure which shows the outline | summary of the speed command profile production | generation at the time of determining with the short section operation | movement in embodiment of this invention (b) The speed command profile at the time of determining with the short section operation in embodiment of this invention Diagram showing generation overview Explanatory drawing of the method of using the most suitable acceleration / deceleration characteristic for the limited operation section using the table which matched the conventional acceleration / deceleration characteristic and the operation section Explanatory drawing of the method that tries to cope with all operation sections by using the conventional acceleration / deceleration characteristics and function together

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

  FIG. 1 shows a process from setting a command speed for operating an articulated robot, which is an example of an industrial robot, and setting an operation section to generating a speed command profile for operating the articulated robot. It is a block diagram for demonstrating.

  The block diagram of FIG. 1 includes a command speed setting unit 1 for setting a command speed, an operation interval setting unit 2 for setting an operation interval, and a command in which the set operation interval is set without acceleration / deceleration. An operation time calculation unit 3 that calculates an operation time required for moving at a speed, a long section acceleration / deceleration time determination unit 4 that determines an acceleration / deceleration time based on basic acceleration / deceleration characteristics in a long section, and a determination of use acceleration / deceleration characteristics 5, a switch 6 that operates based on the determination result of the use acceleration / deceleration characteristic determination unit 5, a long section speed command profile generation section 7 that generates a speed command profile in a long section, and a basic acceleration / deceleration characteristic in a short section A short section acceleration / deceleration time determination unit 8 that determines acceleration / deceleration time based on the above, a correction calculation unit 9 that calculates a correction amount of the basic acceleration / deceleration characteristics of the short section by an arithmetic expression, and an acceleration command processor that is a time change of acceleration. The acceleration command profile changing unit 10 for determining the file, the short zone speed command profile generating unit 11 for generating the speed command profile in the short zone, and the speed command profile generated by the short zone speed command profile generating unit 11 by the low pass filter are smoothed. The speed command profile smoothing unit 12 is described.

  Note that these components are provided in the robot control device among, for example, the manipulator and the robot control device that constitute the articulated robot.

  Although the details of the long section and the short section will be described later, a case where the motion section (movement distance) of the articulated robot is long is referred to as a long section, and a case where it is short is referred to as a short section.

  A process for generating a speed command profile according to the block diagram configured as described above will be described. The speed command profile indicates a change over time in the command speed for operating the articulated robot.

The command speed setting unit 1 is for setting the command speed in the work performed by the articulated robot. The motion section setting unit 2 is for setting a motion section (movement distance) between two points taught by the articulated robot. The operation time calculation unit 3 inputs the output of the command speed setting unit 1 and the output of the operation interval setting unit 2, and moves at the command speed without acceleration / deceleration from the set operation interval and the set command speed. The operation time required for the calculation is calculated. That is, the operation time is calculated by dividing the operation section (movement distance) by the command speed. The long section acceleration / deceleration time determination unit 4 determines the acceleration / deceleration time from the basic acceleration / deceleration characteristics of the long section and the command speed set by the command speed setting unit 1. Note that the basic acceleration / deceleration characteristics of the long section are obtained in advance as described later, and are stored in the long section acceleration / deceleration time determination unit 4. The use acceleration / deceleration characteristic determination unit 5 performs the operation of the articulated robot from the operation time determined by the operation time calculation unit 3 and the acceleration / deceleration time determined by the long interval acceleration / deceleration time determination unit 4 to the long interval. It is determined whether the operation is an operation or a short interval operation. Further, the switch 6 is for switching the connection destination according to the determination result of the use acceleration / deceleration characteristic determination unit 5. Here, the determination of the length of the motion section by the use acceleration / deceleration characteristic determination unit 5 will be described. The determination of the long interval motion and the short interval motion performed by the use acceleration / deceleration characteristic determination unit 5 is based on the operation time T _mov calculated by the operation time calculation unit 3, the command speed, and the basic acceleration / deceleration characteristics of the long interval. This is performed by comparison with the acceleration / deceleration time Tα _L in the long-section operation determined by the section acceleration / deceleration time determination unit 4. The operation time calculation unit 3 calculates the operation time required to move the operation interval set by the operation interval setting unit 2 at the command speed set by the command speed setting unit 1 without acceleration / deceleration. In addition, when following Formula 1 is satisfy | filled, it determines with a short interval operation | movement. On the other hand, when the following formula 1 is not satisfied, it is determined that the motion is a long interval operation.

  Here, the generation of the speed command profile when the use acceleration / deceleration characteristic determination unit 5 determines that the operation is the long section operation will be described with reference to FIG.

  When it is determined that the long section operation is performed, the switch 6 is connected to the long section speed command profile generation unit 7. That is, the use acceleration / deceleration characteristic determination unit 5 and the long section speed command profile generation unit 7 are connected. When it is determined that the motion is a long section motion, the long section speed command profile generation unit 7 sets the command speed determined by the command speed setting unit 1 and the acceleration / deceleration time determined by the long section acceleration / deceleration time determination unit 4. Based on this, a speed command profile is generated. Details of the determination of the acceleration / deceleration characteristics when it is determined to be a long section will be described later with reference to FIG.

  Next, generation of a speed command profile when the use acceleration / deceleration characteristic determination unit 5 determines that the motion is in the short section will be described with reference to FIG.

  When it is determined that the movement is in the short section, the switch 6 is connected to the short section acceleration / deceleration time determination unit 8. That is, the use acceleration / deceleration characteristic determination unit 5 and the short section acceleration / deceleration time determination unit 8 are connected. When it is determined that the movement is a short-section motion, the short-section acceleration / deceleration time determination unit 8 determines the basic acceleration / deceleration characteristics of the short section when the short-section operation is determined and the command speed set by the command speed setting unit 1. Determine the acceleration / deceleration time. The basic acceleration / deceleration characteristics of the short section are obtained in advance as described later, and are stored in the short section acceleration / deceleration time determination unit 8. The correction calculation unit 9 calculates the basic acceleration / deceleration characteristics of the short section by an arithmetic expression that receives the operation time determined by the operation time calculation section 3 and the acceleration / deceleration time determined by the short section acceleration / deceleration time determination section 8. Correction calculation for correction is performed, and a new acceleration / deceleration time is determined from the basic acceleration / deceleration characteristics of the short section. The acceleration command profile changing unit 10 stores a basic acceleration command profile for a long section and a basic acceleration command profile for a short section. When it is determined that the movement is a short section operation, the acceleration command profile changing unit 10 stores the acceleration command profile. The basic acceleration command profile for a short section, which is an acceleration command profile for preventing motor torque saturation. The short section speed command profile generation unit 11 converts the command speed determined by the command speed setting unit 1, the acceleration / deceleration time determined by the correction calculation unit 9, and the acceleration command profile changed by the acceleration command profile change unit 10. Based on this, a speed command profile is generated. The speed command profile smoothing unit 12 applies a low-pass filter to the speed command profile generated by the speed command profile generation unit 11 in a short section, thereby smoothing the waveform of the speed command profile and generating a new speed command profile. To do. The determination of the basic acceleration / deceleration characteristics of the short section when it is determined as the short section will be described later with reference to FIG.

  Next, the determination of the basic acceleration / deceleration characteristics of the long section when it is determined as the long section will be described with reference to FIG. FIG. 2 shows a flowchart for determining the basic acceleration / deceleration characteristics of the long section when it is determined as the long section. The basic acceleration / deceleration characteristics of the long section are determined by the following steps. The following steps are performed using, for example, a computing device such as a personal computer, and are performed in advance before operating the articulated robot.

First, in step S1, the command speed is set to the maximum speed of 100%. For example, when the command speed is 170 deg / sec, it is set to 170 deg / sec, which is 100%. Next, in step S2, an acceleration / deceleration time is determined based on a predetermined adjustment acceleration / deceleration characteristic prepared in advance and a command speed, and the acceleration changes with time using the determined acceleration / deceleration time. Generate an acceleration command profile. Next, in step S3, the generated acceleration command profile is applied to a robot friction model to calculate an estimated peak value τ _peak of the motor torque. Next, in step S4, the estimated peak value τ _{peak of} the motor torque is compared with the saturation limit value τ _limit of the motor torque prepared in advance, and the steps S3 to S5 are repeated until τ _peak ≦ τ _limit. Adjust the deceleration time. Next, in step S6, the acceleration / deceleration time obtained in steps S3 to S5 is recorded. Next, in steps S7 and S8, steps S2 to S6 are repeated while the command speed is decreased by 10% until the command speed reaches 10% of the maximum speed. As described above, by repeating Step S2 to Step S6, a plurality of sets of acceleration / deceleration times with respect to the command speed (%) can be obtained. Then, using each command speed and each acceleration / deceleration time determined by the steps shown in FIG. 2, the basic acceleration / deceleration characteristic of the long section when it is determined as the long section is obtained. That is, the basic acceleration / deceleration characteristics in a long section with the horizontal axis as the command speed (%) and the vertical axis as the acceleration / deceleration time can be obtained.

  Next, the determination of the basic acceleration / deceleration characteristics of the short section when it is determined as the short section will be described with reference to FIG. FIG. 3 shows a flowchart for determining the basic acceleration / deceleration characteristics of the short section when it is determined as the short section. Similar to FIG. 2, the steps shown in FIG. 3 are performed in advance prior to the operation of the articulated robot using, for example, a computing device such as a personal computer. 3 is different from the step shown in FIG. 2 only in step S4, and only this different step S4 will be described below.

According to step S4 of FIG. 3, a value obtained by multiplying the estimated peak value τ _peak of the motor torque by an arbitrary constant α is compared with a saturation limit value τ _limit of the motor torque prepared in advance, and α × τ _peak = τ _limit Steps S3 to S5 are repeated until the acceleration / deceleration time is adjusted. Here, the arbitrary constant α is a value of 1.0 or more that is determined empirically. By doing so, the basic acceleration / deceleration characteristics of the short section when it is determined as the short section are obtained as in the case of FIG. That is, the basic acceleration / deceleration characteristics of a short section with the horizontal axis as the command speed (%) and the vertical axis as the acceleration / deceleration time can be obtained.

  Here, the reason why the conditions of step S4 in FIG. 2 and FIG. 3 are different between the short interval operation and the long interval operation will be described with reference to FIG. FIG. 4A shows a speed command profile that is a time change of the command speed, and FIG. 4B shows a time change of the motor torque.

  In FIG. 4A, the speed command profile 13 is a speed command profile in the long section operation generated by the basic acceleration / deceleration characteristics of the long section determined according to the steps shown in FIG. The speed command profile 14 is a speed command profile in the short section operation generated by the basic acceleration / deceleration characteristics of the long section determined according to the steps shown in FIG. In other words, the speed command profile in the short section operation is an example generated based on the basic acceleration / deceleration characteristics of the long section, not the basic acceleration / deceleration characteristics of the short section.

  In FIG. 4B, a motor torque waveform 15 is a motor torque waveform in the case of the speed command profile 13. The motor torque waveform 16 is a motor torque waveform in the case of the speed command profile 14.

  When the basic command acceleration / deceleration characteristics of the long section determined according to the steps shown in FIG. 2 for determining the basic acceleration / deceleration characteristics of the long section when it is determined to be the long section, As shown in (b), the peak value of the motor torque is smaller than the peak value of the motor torque in the long section operation. This is due to the fact that the maximum speed of the speed command profile when it is determined to be a short section motion does not reach the given command speed. In consideration of this point, it is necessary to determine the acceleration / deceleration characteristics that can increase the peak value of the motor torque and reduce the working time even in the short section operation by setting step S4 as shown in FIG. Further, in the case where the command speed is reached, motor torque saturation is prevented by an acceleration command profile changing unit 10 and a low-pass filter described later.

Equation 2 below shows an arithmetic expression using the acceleration / deceleration time and the operation time as inputs when the short section is determined. In _Equation 2, the operation time T _mov is the operation time required for moving the operation section at the command speed and without acceleration / deceleration, and the acceleration / deceleration time Tα _S is the short section when the short section operation is determined. This is the acceleration / deceleration time determined based on the basic acceleration / deceleration characteristics and the command speed. The acceleration / deceleration time T′α _S in Equation 2 is an acceleration / deceleration time newly determined based on the operation time T _mov and the acceleration / deceleration time Tα _{S. Equation} 2 needs to be a function of the operation time T _mov and the acceleration / deceleration time Tα _S. Further, in order to maintain ease of grasping the change in the acceleration / deceleration time T′α _{S by} a robot operator or the like, it is desirable to keep the maximum order of the arithmetic expression as low as the second order. An example of the arithmetic expression is shown in the following formula 3 and the following formula 4. These arithmetic expressions are derived by a theoretical or empirical method. Note that these arithmetic expressions are provided in the correction calculation unit 9.

  Next, the acceleration / deceleration characteristics that are the relationship between the acceleration / deceleration time and the command speed will be described with reference to FIG. In FIG. 5, the horizontal axis represents the command speed (%), and the vertical axis represents the acceleration / deceleration time. FIG. 5 is a diagram showing acceleration / deceleration characteristics in the long interval operation and the short interval operation.

  In FIG. 5, an acceleration / deceleration characteristic 17 is a basic acceleration / deceleration characteristic of a long section when it is determined as a long section. In the acceleration / deceleration characteristic 17, the acceleration / deceleration time 18 is the acceleration / deceleration time when the command speed is 100% of the maximum speed, and the acceleration / deceleration time 19 is the acceleration / deceleration time when the command speed is 50% of the maximum speed. Time 20 is an acceleration / deceleration time when the command speed is 10% of the maximum speed.

  The acceleration / deceleration characteristic 21 which is the basic acceleration / deceleration characteristic in the short section is the basic acceleration / deceleration characteristic in the short section when it is determined as the short section. In the acceleration / deceleration characteristics 21, the acceleration / deceleration time 22 is the acceleration / deceleration time when the command speed is 100% of the maximum speed, and the acceleration / deceleration time 23 is the acceleration / deceleration time when the command speed is 50% of the maximum speed. Time 24 is an acceleration / deceleration time when the command speed is 10% of the maximum speed.

Further, the acceleration / deceleration characteristic 25 is obtained by an acceleration / deceleration characteristic 21 which is a basic acceleration / deceleration characteristic in a short section and Equation 2 (specifically, Equations 3 and 4) at an arbitrary value having an operation time T _mov. This is an acceleration / deceleration characteristic in a short section. In the acceleration / deceleration characteristics 25, the acceleration / deceleration time 26 is the acceleration / deceleration time when the command speed is 100% of the maximum speed, and the acceleration / deceleration time 27 is the acceleration / deceleration time when the command speed is 50% of the maximum speed. Time 28 is an acceleration / deceleration time when the command speed is 10% of the maximum speed.

  Next, an acceleration command profile that is a time change of the maximum acceleration will be described with reference to FIG. FIG. 6 is a diagram showing acceleration command profiles in the long section motion and the short section motion.

  In FIG. 6, an acceleration command profile 29 indicates an acceleration command profile during a long section operation, and an acceleration command profile 30 indicates an acceleration command profile during a short section operation. By setting the acceleration command profile to the acceleration command profile 30, the peak value of the acceleration is less likely to rise than the acceleration command profile 29, and the maximum speed of the speed command profile reaches the command speed in the short section operation described above. Prevents motor torque saturation during sudden acceleration / deceleration.

  Next, a speed command profile that is a time change of the command speed will be described with reference to FIG. FIG. 7A and FIG. 7B are diagrams for explaining the outline of speed command profile generation when it is determined that the motion is in the short section.

Under the situation where the command speed and the motion section are set, the motion time 31 shown in FIG. 7A indicates the motion time required for moving the motion section at the command speed without acceleration / deceleration. The acceleration / deceleration time 32 in FIG. 7A is an acceleration / deceleration time when it is determined that the long section operation is performed. The acceleration / deceleration time 33 in FIG. 7B is an acceleration / deceleration time newly determined by Equation 2 with the operation time 31 as the operation time T _mov and the acceleration / deceleration time 32 as the operation time Tα _S.

  The speed command profile 34 in FIG. 7A is a speed command profile in the case where the operation section is moved at the command speed without acceleration / deceleration. A speed command profile 35 in FIG. 7B is a speed command profile generated based on the acceleration command profile 30 shown in FIG. 6 and the acceleration / deceleration time 33. The speed command profile 36 in FIG. 7B is a speed command profile newly generated by applying a low-pass filter to the speed command profile 35 in FIG.

  The process will be described below. When the speed command profile 34 having the operation time 31 shown in FIG. 7A is generated from the set command speed and the set operation section, the operation time 31 shown in FIG. The acceleration / deceleration time 32 is compared. When the operation time 31 is less than or equal to the acceleration / deceleration time 32, it is determined that the operation is in the short section. If it is determined that the motion is in the short section, the acceleration command profile 30 shown in FIG. 6 that prevents the motor torque from being saturated, the acceleration / deceleration characteristics 25 that are the acceleration / deceleration characteristics in the short section shown in FIG. A speed command profile 35 based on the acceleration / deceleration time 33 shown in FIG. 7B is newly generated. Further, a low-pass filter is applied to the speed command profile 35 to generate a new speed command profile 36 shown in FIG. The operation of the industrial robot is controlled based on the newly generated speed command profile.

  The cut-off frequency of the low-pass filter is, for example, about 10 Hz, which is near the resonance frequency when a medium-sized articulated robot with a portable weight of 5 kg to 10 kg is targeted. In addition, due to the characteristics of the low-pass filter, the waveform after filtering becomes smoother as the speed command profile suddenly accelerates / decelerates. Therefore, when the maximum speed of the speed command profile reaches the command speed in the short interval operation described above, the acceleration Along with the change of the command profile, saturation of the motor torque is prevented.

  The speed command profile 36 has a rapid acceleration / deceleration so that the peak value of the motor torque is close to the saturation limit value of the motor torque, can realize a short working time, and is smoothed by a low-pass filter. The vibration of can also be suppressed low.

  As described above, according to the speed command profile generation method of the present embodiment, a wide range of operation sections can be obtained for a wide range of operation sections by using two basic acceleration / deceleration characteristics and a simple arithmetic expression for which the tendency of change is easily grasped. A speed command profile that can shorten the work time of the articulated robot can be generated.

  Note that this embodiment can also be applied to servo devices that require acceleration / deceleration control other than articulated robots.

  The speed command profile generation method of the present invention is a speed at which the working time of an industrial robot can be shortened over a wide range of motion sections by means of two acceleration / deceleration characteristics and a simple calculation formula that make it easy to grasp the change tendency. A command profile can be generated, which is industrially useful as a method for generating a speed command profile for an industrial robot.

DESCRIPTION OF SYMBOLS 1 Command speed setting part 2 Operation | movement area setting part 3 Operation | movement time calculation part 4 Long section acceleration / deceleration time determination part 5 Use acceleration / deceleration characteristic determination part 6 Switch 7 Long section speed command profile generation part 8 Short section acceleration / deceleration time determination part 9 Correction Calculation unit 10 Acceleration command profile change unit 11 Short section speed command profile generation unit 12 Speed command profile smoothing unit 13 Speed command profile 14 Speed command profile 15 Motor torque waveform 16 Motor torque waveform 17 Acceleration / deceleration characteristics 18 Acceleration / deceleration time (command speed) At 100% of maximum speed)
19 Acceleration / deceleration time (when command speed is 50% of maximum speed)
20 Acceleration / deceleration time (when command speed is 10% of maximum speed)
21 Acceleration / deceleration characteristics 22 Acceleration / deceleration time (when command speed is 100% of maximum speed)
23 Acceleration / deceleration time (when command speed is 50% of maximum speed)
24 Acceleration / deceleration time (when command speed is 10% of maximum speed)
25 Acceleration / deceleration characteristics 26 Acceleration / deceleration time (when command speed is 100% of maximum speed)
27 Acceleration / deceleration time (when command speed is 50% of maximum speed)
28 Acceleration / deceleration time (when command speed is 10% of maximum speed)
29 Acceleration command profile 30 Acceleration command profile 31 Operation time 32 Acceleration / deceleration time 33 Acceleration / deceleration time 34 Speed command profile 35 Speed command profile 36 Speed command profile 37 Operation time 38 Speed command profile 39 Operation time 40 Speed command profile

Claims (3)

A method for generating a speed command profile of an industrial robot having a rotating arm having a plurality of rotating shafts driven by a motor and operating according to a program taught in advance.
The first acceleration / deceleration characteristic indicating the relationship between the acceleration / deceleration time and the command speed, and the relationship between the acceleration / deceleration time and the command speed are shown. The acceleration / deceleration time is the same when the command speed is the same as the first acceleration / deceleration characteristic. A short second acceleration / deceleration characteristic;
Obtaining a first time, which is the time from the time when the speed is zero to the time when the commanded command speed is reached, with an increasing slope toward the commanded command speed;
Obtaining a second time which is a time required for moving in a predetermined section without acceleration / deceleration at the command speed;
Comparing the first time and the second time;
Obtaining a speed command profile based on the first characteristic if the first time is greater than the second time;
Obtaining a speed command profile based on the second characteristic if the second time is less than or equal to the first time;
Of generating a speed command profile for an industrial robot equipped with The first acceleration / deceleration characteristic is used when a section distance that is a distance of a section in which the articulated robot moves is a first section distance,
The second acceleration / deceleration characteristic is used when the section distance is the second section distance,
The method for generating a speed command profile for an industrial robot according to claim 1, wherein the first section distance is longer than the second section distance. When the section distance is less than the second section distance, a new acceleration / deceleration characteristic indicating the relationship between the new acceleration / deceleration time and the command speed is calculated by a predetermined arithmetic expression using the second acceleration / deceleration characteristic. A speed command profile is obtained from an acceleration command profile different from the acceleration command profile used in the case of the first section distance and the new acceleration / deceleration characteristics, and a speed is applied by applying a low-pass filter to the obtained speed command profile. The method for generating a speed command profile for an industrial robot according to claim 2, wherein the command profile is obtained.

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