JP5118821B2 - Robot control device - Google Patents

Description

  The present invention has a work tool provided in a robot and a sensor that is arranged on the work tool and detects the shape of a work object, operates the work tool along a preset main trajectory, and The present invention relates to a robot control device that corrects the operation of the work tool by the output of a sensor.

  Conventionally, there has been known a robot control device in which a laser sensor for detecting the shape of a workpiece on the traveling direction side is mounted on a work tool of a welding robot so that the welding robot performs an accurate work when performing welding. (For example, refer to Patent Document 1). In such a robot control device, prior to the welding operation, the feature point of the groove of the workpiece is detected by a laser sensor, and the target position and orientation of the work tool are calculated by connecting them three-dimensionally. is doing. Then, the work tool is operated along a preset main trajectory, and the operation position and posture of the work tool are corrected in accordance with the detection results sequentially obtained from the laser sensors.

  With reference to FIG. 14, the control which the above control apparatuses perform is demonstrated. The control device 101 includes a robot control unit 111 that controls a welding robot and a sensor control unit 121 that controls a laser sensor. The robot control unit 111 includes a main trajectory interpolation point calculation processing unit 112 that calculates a main trajectory interpolation point from input teaching data, a copying correction processing unit 113 that performs copying correction based on the target position and orientation of the work tool, and A current position calculation processing unit 114 that calculates the current position and orientation of the work tool.

The main trajectory interpolation point calculation processing unit 112 calculates interpolation points (hereinafter referred to as main trajectory interpolation points) on a plurality of main trajectories indicating the position and orientation of the work tool from the teaching data prior to the movement of the work tool. . The calculated main trajectory interpolation points are sequentially output to the scanning correction processing unit 113 and sent to the current position calculation processing unit 114. The current position calculation processing unit 114 calculates the current position and orientation of the work tool, and transmits the current position and orientation to the sensor control unit 121. The sensor control unit 121 compares the current position and posture with the shape detection result of the workpiece by the laser sensor, sets the target position and posture of the work tool, and copies the target position and posture to the correction processing unit 113. Send back. The scanning correction processing unit 113 replaces the main trajectory interpolation point with the received target position and orientation. By performing such feedback control, the control device 101 corrects the target position and orientation of the work tool so as to cause the welding robot to perform accurate work.
JP-A-9-76065

  By the way, in the control apparatus 101 as described above, it takes time until the scanning correction processing unit 113 receives the target position and orientation after the current position calculation processing unit 114 calculates the current position and orientation. End up. Therefore, during this time, the main trajectory interpolation point calculation processing unit 112 continues to output the main trajectory interpolation point, and the set target position and orientation are corrected with respect to the previous main trajectory interpolation point. A situation like this can occur. For example, correction is performed so as to replace the target position and orientation set for the main trajectory interpolation point T1 with the main trajectory interpolation point Tn newly output by the main trajectory interpolation point calculation processing unit 112. When the target position and orientation are replaced with respect to the previous main trajectory interpolation point in this way, correction is performed so as to pull back with respect to the traveling direction of the work tool, so that a position error occurs in the traveling direction. . Since these position errors are sequentially accumulated, a phenomenon may occur in which the actual weld length by the scanning correction becomes shorter than a preset weld length. The cumulative position error tends to increase as the welding length increases and the number of curved portions in the welded portion increases. Therefore, depending on the welding conditions, the influence of this position error may not be negligible.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to detect a position error that occurs in the traveling direction of the work tool when the operation of the work tool is corrected by copying a sensor that detects the shape of the work object. It is an object of the present invention to provide a robot control device that can suppress the above-described problem.

To achieve the above object, a robot control apparatus according to the present invention includes a work tool provided in the robot, and a sensor that is mounted on the work tool and detects the shape of a work object prior to the work. The work tool is operated along a plurality of main trajectory interpolation points on the preset main trajectory and indicating the position and orientation of the work tool, and the main trajectory interpolation point is corrected by the output of the sensor. a control apparatus for a robot, the main and the current position calculating means for calculating a current position and orientation of the work tool corresponding to the trajectory interpolation point, the current position and orientation the calculated, the corresponding main track interpolation points Storage means for storing together with the serial number assigned to the work tool, the work tool set based on the calculated current position and orientation and the output of the sensor. The target position and orientation, the target position setting means for setting together with the serial number assigned to the main track interpolation points the corresponding, and the target position and orientation which is pre-Symbol set, and the target position and orientation which are those the setting Calculate the amount of deviation from the current position and orientation stored in the storage means in association with each other by the serial number, and based on the amount of deviation , corresponds to the serial number used to calculate the amount of deviation Correction means for correcting the main trajectory interpolation point to be corrected based on the shift amount .

According to this configuration, the robot control device calculates the current position and posture of the work tool, stores the calculated current position and posture, and the work target detected by the calculated current position and posture and the sensor. The target position and posture of the work tool are set from the shape of the object. Then, a deviation amount between the set target position and posture and the stored current position and posture is calculated, and the current position and posture of the work tool are copied and corrected based on the deviation amount.

  As described above, when the current position and orientation of the work tool are stored and the amount of deviation between the stored current position and orientation and the set target position and orientation is calculated, the target position and orientation can be set. The target position and posture with respect to the used current position and posture can be grasped. For this reason, the robot control device can manage the target position and orientation for a preset interpolation point on the main trajectory (main trajectory interpolation point) for each main trajectory interpolation point.

  Therefore, even if the previous main trajectory interpolation point is already output at the time of setting the target position and orientation, the target position and orientation are not replaced with respect to the previous main trajectory interpolation point. It is possible to prevent a position error from occurring in the traveling direction of the work tool due to the replacement of the target position and posture. As a result, it is possible to avoid as much as possible the situation where the actual trajectory length due to the scanning correction becomes shorter than the preset trajectory length of the work tool.

  In the above configuration, the correction unit may calculate a corrected shift amount obtained by removing the component in the main trajectory direction from the shift amount, and correct the operation of the work tool based on the corrected shift amount. Good.

  When correcting the operation of the work tool by copying, if the work tool moves at a predetermined speed and the target positions are set in a predetermined cycle, the distance between the target positions is maintained at a predetermined distance. For this reason, when the target position is set at a position shifted from the main track, the main track direction component between the target positions becomes shorter than the distance between the target positions. As a result, position errors in the main trajectory direction may accumulate, and the length in the main trajectory direction generated by the scanning correction may be shortened with respect to the preset length of the main trajectory. In addition, there may be a detection accuracy error of the sensor, a trajectory error of the welding robot, and the like, and these errors may also occur in the main trajectory direction.

  In this regard, according to the configuration, the robot control device calculates a correction deviation amount obtained by removing the component in the main trajectory direction from the deviation amount obtained from the current position and posture, the target position and the posture, and the correction deviation. Since the operation of the work tool is corrected based on the amount, occurrence of a position error in the main trajectory direction can be suppressed. For this reason, it is possible to prevent position errors from accumulating in the main trajectory direction and prevent the length of the main trajectory direction generated by copying correction from being shortened with respect to the preset main trajectory length. it can.

  Further, in the above configuration, an adaptive function for changing a work condition including at least a moving speed of the work tool according to a shape of a work target detected by the sensor during work of the work tool, and the adaptive function When the moving speed of the work tool is changed by the above, the number of main trajectory interpolation points set on the main trajectory is changed based on the moving speed before the operation of the work tool, and a new main tool is changed. Interpolation point recalculation means for calculating the trajectory interpolation point may be further provided.

  According to this configuration, the robot control device has an adaptive function for changing the work condition including at least the moving speed of the work tool according to the shape of the work object detected by the sensor during the work of the work tool. . Then, when the moving speed of the work tool is changed by the adaptive function, the main trajectory interpolation point set on the main trajectory prior to the operation of the work tool, that is, the main trajectory interpolation that becomes the operation target after the work tool. The number of points is changed based on the moving speed, and a new main trajectory interpolation point is calculated. For this reason, even when the distance between the main trajectory interpolation points changes due to the change in the movement speed of the work tool, the number of main trajectory interpolation points is changed based on the movement speed, so that the preset work tool It is possible to suppress the actual track length from changing with respect to the track length. That is, when the moving speed becomes slower than the preset speed, the number of main trajectory interpolation points is increased, and when the moving speed becomes faster than the preset speed, the main trajectory interpolation point By reducing the number, the actual track length of the work tool can be adjusted to a preset track length.

  Further, in the above configuration, during the work of the work tool, moving means for moving at least one of the work object and the robot along preset movement data, and a moving speed of the work tool by the adaptive function Corresponding interpolation point calculation means for newly calculating an interpolation point of the movement data corresponding to a new main trajectory interpolation point calculated by the interpolation point recalculation means. May be.

  According to this configuration, the robot control apparatus moves at least one of the work object and the robot along the movement data set in advance during the work of the work tool, and determines the relative position between the work object and the robot. It has a moving means to change. Then, when the moving speed of the work tool is changed by the adaptive function, an interpolation point of the movement data is newly calculated corresponding to the new main trajectory interpolation point calculated by the interpolation point recalculation means. For this reason, it is possible to prevent the movement means from continuing to move along the preset movement data even though the movement speed of the work tool is changed. Can be changed synchronously. Therefore, the relative position between the work object and the robot can be prevented from deviating from the preset relative position. The deviation of the posture with respect to the object can be suppressed. Thereby, a change in the track length of the work tool due to a shift in the main track direction, a work defect due to a shift in posture, and the like can be suitably suppressed.

Further, in the above configuration, a positioner that moves the work object in one axial direction with respect to the work tool, and correction for the movement direction of the positioner based on the output of the sensor is ignored, and the work tool and the positioner are ignored. and control means for controlling the operation, may be further provided with.

  According to this configuration, the robot control device includes the positioner that moves the work object in one axial direction with respect to the work tool, and determines the robot's shape based on the shape of the work object detected by the sensor disposed on the work tool. When the movement is corrected by copying, the movement of the work tool and the positioner is controlled ignoring the correction with respect to the movement direction of the positioner. For this reason, it is possible to suppress a displacement in the moving direction of the positioner caused by the scanning correction, that is, a position error, and the actual working track length by the scanning correction becomes shorter than the working track length of the working tool set in advance. Such a situation can be avoided.

In the configuration of the robot control device described above, the sensor may be a scanning laser sensor that measures a distance to a work object by emitting and receiving light of a laser.
According to this configuration, the sensor that detects the shape of the work object is a scanning laser sensor that measures the distance to the work object by laser emission and reception. For this reason, even if such a non-contact type sensor causes a detection accuracy error to some extent, the position error in the advancing direction of the work tool is controlled by the control of the robot controller. Or generation | occurrence | production of the position error of the moving direction of a positioner can be suppressed. Therefore, it is possible to suppress the actual track length from being shortened by the scanning correction from the preset track length of the work tool.

(First embodiment)
Hereinafter, a first embodiment in which a robot control device according to the present invention is applied to a welding robot control device will be described with reference to FIGS.

  FIG. 1 is a block diagram illustrating a configuration of a control apparatus 1 for a welding robot. The welding robot control apparatus 1 controls the workpiece (work object) W so as to automatically perform arc welding, and includes a manipulator 11 that performs a welding operation, and a robot control unit 21 that controls the manipulator 11. A laser sensor 31 serving as a sensor for detecting the shape of the workpiece W and a sensor control unit 41 for controlling the laser sensor 31 are provided.

  The manipulator 11 includes a base member 12 fixed to a floor or the like, and a plurality of arms 13 connected via a plurality of shafts. A welding torch 14 as a work tool is provided at the distal end portion of the arm 13 located on the most distal side. The welding torch 14 includes a wire 15 as a filler material, generates an arc between the tip of the wire 15 fed by a feeding device (not shown) and the workpiece W, and welds the wire 15 with the heat. To weld the workpiece W. A plurality of motors are disposed between the arms 13, and the welding torch 14 can be freely moved back and forth and left and right by driving the motors.

  The robot control unit 21 controls the motor to drive the welding torch 14 along a main track of preset teaching data. Further, the robot control unit 21 outputs welding conditions such as a welding current and a welding voltage to the welding power source 51, and causes the welding operation to be performed by electric power supplied from the welding power source 51 through the power cable 52.

  The laser sensor 31 is a scanning type laser sensor that measures the distance to the workpiece W by emitting and receiving laser light, and is mounted on the welding torch 14. FIG. 2 shows a schematic configuration of the laser sensor 31. The laser sensor 31 includes a light emitting unit 32 that emits a laser beam toward the workpiece W, a light receiving unit 33 that receives a laser beam reflected by the workpiece W, and a mirror scanner 34 that reflects the emitted and received laser beam. The laser emitted by the light emitting unit 32 is reflected by the mirror scanner 34 and is irradiated onto the workpiece W. The laser diffusely reflected by the workpiece W is reflected by the mirror scanner 34 and guided to the light receiving unit 33. The light receiving unit 33 is composed of a CCD line sensor, and measures the distance from the center of gravity of the received light amount distribution to the workpiece W. Further, the mirror scanner 34 is configured to be rotatable by a predetermined angle around the rotation axis 34a, and measures the distance while scanning the range from the position A to the position B of the workpiece W, for example, by the rotation of the mirror scanner 34.

  The sensor control unit 41 drives and controls the laser sensor 31 and detects the groove shape of the workpiece W from the measured distance information. When the workpiece W to be measured is a lap joint as shown in FIG. 2, the mirror scanner 34 is rotated and the distance is measured for each sampling point while scanning a predetermined range. Data is obtained. The sensor control unit 41 creates a groove shape Wf of the workpiece W from a plurality of sampling points C, and acquires a feature point D of the workpiece W from the groove shape Wf. The sensor control unit 41 acquires the feature point D of the workpiece W by measuring the distance by the same method even at the position where the welding torch 14 has moved.

  Then, as shown in FIG. 4, the three-dimensional trajectory E of the feature points is generated by connecting the acquired feature points D together. The sensor control unit 41 sets the target position and orientation of the welding torch 14 from the three-dimensional trajectory E thus obtained. In other words, the target position is set with the tangent vector of the three-dimensional trajectory E as the traveling direction vector v, and the target posture is set by giving a predetermined target relative angle α to the normal line of the workpiece W.

  Note that when setting the target position and orientation, only the position and orientation relative to the sensor coordinate system based on the laser sensor 31 can be calculated from only the groove information detected by the laser sensor 31. For this reason, the sensor control unit 41 acquires the current position and orientation of the welding torch 14 from the robot control unit 21, and changes from the sensor coordinate system based on the laser sensor 31 to the reference coordinate system of the robot based on the manipulator 11. Is converted as appropriate. That is, the sensor control unit 41 uses the current position and orientation acquired from the robot control unit 21, the homogeneous transformation matrix from the sensor coordinate system stored in advance in the sensor control unit 41 to the reference coordinate system, and the laser sensor 31. The target position and orientation in the reference coordinate system are calculated from the detected groove information.

  Next, control performed by the robot control unit 21 and the sensor control unit 41 when a welding operation is performed by the manipulator 11 will be described. Before the welding operation is performed, the robot controller 21 receives teaching data indicating the operation of the manipulator 11 when welding is performed, welding conditions, and the like. FIG. 5 shows a block diagram of the robot control unit 21 and the sensor control unit 41.

The robot control unit 21 includes a main trajectory interpolation point calculation processing unit 22 that calculates the main trajectory interpolation point of the welding torch 14 from the teaching data, and a scanning correction processing unit 23 that performs copying correction based on the target position and orientation of the welding torch 14. A main trajectory interpolation point buffer 24 that temporarily stores main trajectory interpolation points, and a current position calculation processing unit 25 that calculates the current position and orientation of the welding torch 14. In addition, the robot control unit 21 responds to the first buffer 26 that temporarily stores a serial ID assigned by assigning a serial number to the main trajectory interpolation point, and the current position and posture calculated by the current position calculation processing unit 25. together with the serial number assigned to the main track interpolation points and a second buffer 27 as a storage means for temporarily storing.

  The main trajectory interpolation point calculation processing unit 22 calculates a plurality of main trajectory interpolation points indicating the position and orientation of the welding torch 14 from the teaching data prior to the movement of the welding torch 14. The calculated main trajectory interpolation points are sequentially output to the scanning correction processing unit 23. Then, the main trajectory interpolation point is sent from the scanning correction processing unit 23 to the current position calculation processing unit 25 via the main trajectory interpolation point buffer 24.

A current position calculation processing unit 25 as current position calculation means calculates the current position and orientation of the welding torch 14 based on the position detection value read from an encoder or the like built in the manipulator 11. The calculated current position and orientation are transmitted to the sensor control unit 41 and stored in the second buffer 27 together with the serial number assigned to the corresponding main trajectory interpolation point based on the serial ID of the first buffer 26. Is done. For example, when the calculated current position and orientation are those of the main trajectory interpolation point Tr1 , the calculated current position and orientation and the main trajectory interpolation point Tr1 are stored in association with each other in the second buffer 27. The

  The sensor control unit 41 as the target position setting means acquires the current position and posture from the current position calculation processing unit 25 and compares the result of detection of the shape of the workpiece W by the laser sensor 31 with the target position and posture of the welding torch 14. Set. The set target position and orientation are transmitted to the copying correction processing unit 23.

  The scanning correction processing unit 23 as a correction unit acquires the target position and orientation from the sensor control unit 41, and refers to the current position and orientation used when setting the target position and orientation with reference to the serial number. Call from buffer 27. Then, the acquired target position and posture are compared with the called current position and posture, and the deviation amount is calculated. The position shift amount d1 at the main trajectory interpolation point Tr1 is obtained from the current position Pp1 and the target position Pt1 as shown in the following expression (1).

但し、

However,

とする。

And

  In this way, the target position and posture and the current position and posture are managed by the serial ID assigned to each main trajectory interpolation point. That is, by assigning a serial number to each main trajectory interpolation point, the history of the position and orientation of the main trajectory interpolation point is managed. Therefore, the main trajectory interpolation point calculation processing unit 22 performs the main trajectory interpolation point between the time when the current position calculation processing unit 25 calculates the current position and posture and the time when the scanning correction processing unit 23 receives the target position and posture. Even if there is an output of ## EQU3 ##, the copy correction that sets the target position and orientation for the newly output main trajectory interpolation point is not performed. Accordingly, the correction that pulls back the welding torch 14 in the traveling direction is not performed, and the position error that occurs in the traveling direction can be suppressed.

  The scanning correction processing unit 23 further performs the following control in order to suppress a position error that occurs in the traveling direction of the welding torch 14. The above-described scanning correction is performed in a state where the welding torch 14 is moving at a predetermined traveling speed set by the teaching data. For this reason, when the main trajectory interpolation point is output by the main trajectory interpolation point calculation processing unit 22 in a predetermined cycle, the distance between the main trajectory interpolation points is kept constant. Thereby, when an interpolation point is set at a position deviated from the main trajectory by scanning correction, the main trajectory direction component between the main trajectory interpolation points becomes slightly shorter than the distance between the main trajectory interpolation points.

  FIG. 6 shows the position of the main trajectory interpolation point when the main trajectory is a straight line. FIG. 6A shows the positions of the main trajectory interpolation points generated by the main trajectory interpolation point calculation processing unit 22, and the main trajectory interpolation points are located on the main trajectory with a constant interval G. FIG. 6B shows the positions of the main trajectory interpolation points when the main trajectory interpolation points are corrected at positions shifted from the main trajectory by scanning correction. The intervals between the main trajectory interpolation points are shown in FIG. The interval G is the same as in the case of a).

  When the main trajectory interpolation points are corrected as shown in FIG. 6B, a slight position error occurs in the main trajectory direction at each main trajectory interpolation point, with respect to a preset main trajectory length H. The length in the main trajectory direction generated by the scanning correction is shortened by the error I. Such a position error becomes larger as the welding length becomes longer and the stability of measurement by the laser sensor 31 becomes worse. Further, when the main trajectory is a curve, the position error is larger than when the main trajectory is a straight line. Therefore, the scanning correction processing unit 23 performs control for removing the error I as shown in FIG.

  FIG. 7 shows the deviation d1 when the main trajectory interpolation point is the origin O in the reference coordinate system S1. The scanning correction processing unit 23 generates a main trajectory coordinate system S2 based on a preset main trajectory direction. The main trajectory coordinate system S2 uses the Y2 axis formed in the main trajectory direction and the X2 axis and the Z2 axis formed orthogonal to each other in a plane orthogonal to the Y2 axis and passing through the origin O as coordinate axes. . The scanning correction processing unit 23 converts the shift amount d1 from the reference coordinate system S1 to the main trajectory coordinate system S2. The homogeneous transformation matrix F1 from the reference coordinate system S1 to the main orbit coordinate system S2 at this time is expressed as follows.

但し、

However,

である。

It is.

  Here, vectors e, f, and g represent normalized vectors of the X1, Y1, and Z1 axes viewed from the main orbit coordinate system S2, respectively. The scanning correction processing unit 23 converts the deviation amount d1 into the main trajectory coordinate system S2, and then removes the component in the Y2 axis direction, which is the main trajectory direction, to create a corrected deviation amount d′ 1. That is, when the shift amount d1 is expressed as (du1, dv1, dw1) in the main trajectory coordinate system, the corrected shift amount d′ 1 is (du1, 0, dw1). For this reason, as shown in FIG. 7, the corrected shift amount d′ 1 is represented as a vector in which the shift amount d1 is projected onto a plane formed by the X2 axis and the Z2 axis.

  Then, the scanning correction processing unit 23 converts the correction deviation amount d′ 1 from the main trajectory coordinate system S2 to the reference coordinate system S1. The homogeneous transformation matrix F2 from the main orbit coordinate system S2 to the reference coordinate system S1 at this time is expressed as follows.

但し、

However,

である。

It is.

  Here, the vectors h, i, and j represent normalized vectors of the X2, Y2, and Z2 axes as viewed from the reference coordinate system S1, respectively. The scanning correction processing unit 23 scans and corrects the position and orientation at the main trajectory interpolation point based on the correction deviation amount d′ 1 calculated as described above. That is, as shown in the following formula (12), the corrected deviation d′ 1 is added to the main trajectory interpolation point Tr1, and the corrected target main trajectory interpolation point T′r1 is obtained.

このように目標主軌道補間点を求めると、レーザセンサ３１が算出したずれ量ｄ１のうち、主軌道方向以外の方向に対してのみ倣い補正を行うことになるため、溶接トーチ１４の主軌道方向距離に影響を与えないようにすることができる。このため、溶接トーチ１４が教示データにより設定された所定の進行速度で移動しているときに、主軌道方向の位置誤差の発生をなくすことができる。

When the target main trajectory interpolation point is obtained in this manner, the correction correction is performed only in a direction other than the main trajectory direction out of the deviation d1 calculated by the laser sensor 31, and therefore the main trajectory direction of the welding torch 14 is determined. It is possible to avoid affecting the distance. For this reason, when the welding torch 14 is moving at a predetermined traveling speed set by the teaching data, it is possible to eliminate the occurrence of a position error in the main track direction.

  FIG. 8 shows the position of the main trajectory interpolation point when the scanning correction is performed on the groove of the same workpiece W as in FIG. FIG. 8A shows the position of the main trajectory interpolation point generated by the main trajectory interpolation point calculation processing unit 22 as in FIG. 6A, and FIG. The position of the target main trajectory interpolation point corrected based on the deviation amount is shown. When the main trajectory interpolation point is corrected based on the correction deviation amount, as shown in FIG. 8B, the scanning correction is performed in the direction in the vertical plane with respect to the main trajectory, but the correction is performed in the main trajectory direction. Not done. Therefore, since the gap G in the main trajectory direction between the main trajectory interpolation points does not change even by correction, the error I with respect to the length H of the main trajectory as shown in FIG. 6B can be removed.

  The corrected target main trajectory interpolation point is sent to the current position calculation processing unit 25 via the main trajectory interpolation point buffer 24. Then, the copy correction is repeated by the same procedure. The robot control unit 21 and the sensor control unit 41 of the control device 1 control the operation of the welding torch 14 by performing such feedback control, and suppress the position error generated in the traveling direction of the welding torch 14.

According to the welding robot control apparatus 1 of the first embodiment, the following effects can be obtained.
(1) In the first embodiment, the control device 1 uses the target position and posture set by the sensor control unit 41 and the current position and posture used when setting the target position and posture for each main trajectory. Management is based on the serial ID assigned to the interpolation point. Then, the scanning correction processing unit 23 of the robot control unit 21 calculates a deviation amount between the target position and posture and the current position and posture, and performs a scanning correction on the operation of the welding torch 14 based on the deviation amount. Therefore, the main trajectory interpolation point calculation processing unit 22 performs the main trajectory interpolation point between the time when the current position calculation processing unit 25 calculates the current position and posture and the time when the scanning correction processing unit 23 receives the target position and posture. , The scanning correction processing unit 23 does not perform scanning correction that sets the target position and orientation for the newly output main trajectory interpolation point. Accordingly, the correction that pulls back the welding torch 14 in the traveling direction is not performed, and the position error that occurs in the traveling direction can be suppressed. Thereby, the situation where the actual welding length by scanning correction becomes shorter than the welding length set beforehand can be avoided as much as possible.

  (2) In the first embodiment, the control device 1 calculates a corrected deviation amount obtained by removing the component in the main trajectory direction from the deviation amount obtained from the current position and posture, the target position and the posture, and the corrected deviation amount. Based on this, the position and orientation at the main trajectory interpolation point are copied and corrected. For this reason, it is possible to suppress the occurrence of a position error in the main trajectory direction, and the main trajectory direction generated by scanning correction for the length of the main trajectory set in advance due to the accumulation of the position errors. Can be prevented from becoming shorter.

(Second Embodiment)
Next, a second embodiment in which the robot control device according to the present invention is applied to a welding robot control device will be described with reference to FIGS. In the control device of the second embodiment, the configuration of the robot control unit 21, the laser sensor 31, the sensor control unit 41, the welding power source 51, and the control of the scanning correction of the welding torch 14 are the same as those of the first embodiment. However, the point which has a mechanism which moves the manipulator 11 and the workpiece | work W, and the point provided with an adaptive welding function differ from 1st Embodiment. In the embodiments described below, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions thereof are omitted or simplified.

  FIG. 9 is a block diagram illustrating a configuration of the control device 2 of the welding robot according to the second embodiment. The control device 2 includes a positioner 71 that moves the workpiece W and a slider 72 that moves the manipulator 11. The positioner 71 is configured to hold the workpiece W and rotate and slide the workpiece W by driving a motor or the like so that the workpiece W can take an arbitrary posture with respect to the welding torch 14 of the manipulator 11. The operation of the positioner 71 is driven and controlled by the robot controller 21. The slider 72 is configured to be able to slide the manipulator 11 in one axial direction (SL direction in FIG. 9) by driving a motor or the like. The slider 72 allows the welding torch 14 to always face the workpiece W even when the workpiece W is relatively large. The operation of the slider 72 is driven and controlled by the robot control unit 21. Here, the positioner 71 and the slider 72 correspond to moving means for moving at least one of the workpiece W and the manipulator 11 along preset teaching data.

  The robot controller 21 simultaneously controls the change of the posture of the workpiece W by the positioner 71, the movement of the manipulator 11 by the slider 72, and the movement of the welding torch 14, thereby controlling the synchro motion of the positioner 71, the slider 72 and the welding torch 14. I do. Such synchro motion control is performed based on preset teaching data, whereby the relative position between the welding torch 14 and the workpiece W is positioned. The control device 2 performs control such that the welding torch 14 is always arranged toward the positioner 71 (downward) so that a good welding operation is performed. Further, the relative speed of the workpiece W with respect to the welding torch 14 is controlled to be a constant speed designated by the synchro motion control.

  Moreover, the control apparatus 2 is provided with the adaptive welding function as an adaptive function. The adaptive welding function changes welding conditions such as the welding speed, welding current, and welding voltage in real time based on the gap amount and groove area measurement values at the groove of the workpiece W by the laser sensor 31, and causes the welding failure. It is a function to reduce For example, when it is detected that the gap amount at the groove of the workpiece W is large, the moving speed of the welding torch 14 is lowered to suppress the occurrence of poor welding at that location. The sensor control unit 41 has a conversion table in which welding conditions such as a welding speed corresponding to a measured value such as a gap amount are stored in advance. When a measurement value is input from the laser sensor 31, the sensor control unit 41 calculates welding conditions such as a welding speed by the conversion table. The calculated welding conditions are transmitted to the robot control unit 21 together with the target position and posture of the welding torch 14 set by the sensor control unit 41. The robot controller 21 controls the operation of the welding torch 14 in real time based on the received welding conditions.

  Control when the moving speed of the welding torch 14 is changed by the adaptive welding function will be described. The robot control unit 21 has an adaptive speed Va for setting the moving speed of the welding torch 14 and performs control so that the moving speed of the welding torch 14 becomes the adaptive speed Va. Assuming that the teaching speed of the welding torch 14 based on preset teaching data is Vs, the adaptive speed Va is as follows at the start of welding.

溶接が開始された後、センサ制御部４１は、ギャップ量等の計測値に基づいて溶接トーチ１４の目標速度Ｖｔを適宜算出し、その結果をロボット制御部２１に送信する。ロボット制御部２１は、センサ制御部４１から目標位置及び姿勢とともに目標速度Ｖｔを受信すると、アダプティブ速度Ｖａを以下のように設定する。

After the welding is started, the sensor control unit 41 appropriately calculates the target speed Vt of the welding torch 14 based on the measured value such as the gap amount and transmits the result to the robot control unit 21. When the robot controller 21 receives the target speed Vt together with the target position and orientation from the sensor controller 41, the robot controller 21 sets the adaptive speed Va as follows.

ここで、主軌道補間点に対する補間周期をＴｉとすると、１補間点当たりの主軌道上の移動距離、すなわち主軌道補間点間距離Ｄｐ_{（ｎ＿ｎ＋１）}は、以下のようになる。

Here, _assuming that the interpolation cycle for the main trajectory interpolation point is Ti, the movement distance on the main trajectory per interpolation point, that is, the distance Dp _{(n_n + 1)} between the main trajectory interpolation points is as follows.

また、主軌道上の累積移動距離をＤｆ_（ｎ）とすると、累積移動距離Ｄｆ_（ｎ）は以下のようにして更新されていく。

If the cumulative travel distance on the main track is Df _(n) , the cumulative travel distance Df _(n) is updated as follows.

このようにアダプティブ溶接機能が作用すると、アダプティブ速度Ｖａのみが変更されてしまうため、主軌道補間点間距離Ｄｐは教示データから生成されたものと異なる値になる。主軌道補間点の数は教示データから求められた数に固定されているため、主軌道補間点間距離Ｄｐが変化すると、累積移動距離Ｄｆに誤差が生じ、実際の溶接長が予め設定された溶接長に対して変化してしまうおそれがある。また、溶接トーチ１４の移動速度の変更に伴って、溶接トーチ１４とポジショナ７１及びスライダ７２との動作の同期が正確に行われなくなると、ワークＷに対する溶接トーチ１４の姿勢が不適切となる場合や、予め設定された溶接長を守ることができなくなる場合がある。

When the adaptive welding function operates in this way, only the adaptive speed Va is changed, so that the distance Dp between the main trajectory interpolation points is different from that generated from the teaching data. Since the number of main trajectory interpolation points is fixed to the number obtained from the teaching data, if the distance Dp between the main trajectory interpolation points changes, an error occurs in the cumulative movement distance Df, and the actual welding length is preset. There is a possibility of changing with respect to the welding length. Further, when the operation of the welding torch 14 and the positioner 71 and the slider 72 is not accurately synchronized with the change in the moving speed of the welding torch 14, the posture of the welding torch 14 with respect to the workpiece W becomes inappropriate. Or, it may become impossible to keep the preset welding length.

  As an example, the case where welding is performed on the workpiece W as shown in FIG. 10 will be described. The welding torch 14 performs welding in a section from the position WA to the position WE of the workpiece W. Welding torch 14 and positioner 71 operate based on preset teaching data. As teaching data of the welding torch 14 and the positioner 71, in addition to the position WA as the start point and the position WE as the end point, a position WB where the main track changes from a straight line to an arc, a position WC which is the midpoint of the arc, Five positions WD where the main trajectory changes from an arc to a straight line are given as teaching points.

  When performing the welding process in the section from the position WA to the position WE of the workpiece W, the robot control unit 21 sets the welding torch 14 in a state where the welding torch 14 is at the position WA as shown in FIG. Start linear movement. Then, when the welding torch 14 reaches the position WB, the rotational motion of the positioner 71 is started, and as shown in FIG. 10B, the welding torch 14 passes through the position WC which is the rotation midpoint, and FIG. When the position WD is reached as shown in (c), the rotational movement of the positioner 71 is terminated. That is, when the welding torch 14 moves from the position WB to the position WD, the welding torch 14 and the positioner 71 operate together, and synchro motion control is performed. When the welding torch 14 reaches the position WE, the linear movement of the welding torch 14 is terminated, and the welding process of the workpiece W is terminated.

  FIG. 11 shows a state when the adaptive welding function is activated in the welding process set as shown in FIG. It is assumed that the adaptive welding function acts during the period from the position WA to the position WB, and the moving speed of the welding torch 14 decreases in a predetermined section. In this case, when the moving speed of the welding torch 14 decreases, the distance between the main trajectory interpolation points set in advance is shortened, so that the robot control unit 21 moves the position WB as shown in FIG. It is determined that the welding torch 14 has reached the position WB at the position WB ′ before the position. Then, the rotary motion of the positioner 71 is started in a state where the welding torch 14 is at the position WB ′. Therefore, as shown in FIG. 11B, when the robot control unit 21 recognizes that the welding torch 14 has reached the position WC that is the midpoint of rotation of the positioner 71, the welding torch 14 is positioned at the position WC. It is in a state where it has reached only the position WC ′ immediately before. At this time, the welding torch 14 faces the workpiece W with a receding angle β as shown in FIG. When the welding torch 14 has a receding angle, the shield gas supplied from the welding torch 14 is ejected in the direction opposite to the traveling direction, so that the possibility of poor welding is increased.

  Then, as shown in FIG. 11C, the robot controller 21 ends the rotational movement of the positioner 71 when the welding torch 14 reaches a position WD ′ before the position WD. The state where the welding torch 14 has the receding angle continues until the welding torch 14 reaches the position WD where the arc portion of the workpiece W ends from the position WB '. Then, when the welding torch 14 reaches the position WE ′ before the position WE, the robot controller 21 ends the linear movement of the welding torch 14 and ends the work W welding process. Thus, since the welding process is completed when the welding torch 14 is at the position WE ', the actual welding length is shorter than the preset welding length.

  Therefore, the control device 2 of the present embodiment suppresses a position error in the traveling direction of the welding torch 14 generated by the adaptive welding function, and the welding torch 14 as shown in FIG. Control for eliminating the state where the welding length is shortened as shown in FIG. Below, the control which the control apparatus 2 performs is demonstrated.

  FIG. 12 is a block diagram of the robot control unit 21 and the sensor control unit 41 of the control device 2. In addition to the configuration of the control device 1 according to the first embodiment, the control device 2 includes a main trajectory interpolation point number calculation processing unit 28 that recalculates the number of main trajectory interpolation points when the adaptive welding function is activated. The main trajectory interpolation point calculation processor 28 calculates the main trajectory from the teaching point distance Dt (for example, the distance from the position WA to the position WB shown in FIG. 10) when the adaptive welding function is applied and the adaptive speed Va is changed. The digestibility Rp is calculated. The main trajectory digestion rate Rp represents the degree of progress of the interpolation operation between the teaching points, and is expressed as follows by the distance Dt between the teaching points and the current cumulative movement distance Df.

ここで、Ｒｐが１未満の場合は、教示点間の補間動作が完了していないため、主軌道補間点数算出処理部２８は、アダプティブ速度Ｖａが変更された後の教示点間の残存距離Ｄｒを以下のように求める。

Here, when Rp is less than 1, since the interpolation operation between the teaching points is not completed, the main trajectory interpolation point number calculation processing unit 28 determines the remaining distance Dr between the teaching points after the adaptive speed Va is changed. Is obtained as follows.

そして、教示点間の残存距離Ｄｒとアダプティブ速度Ｖａとから、残存距離Ｄｒ中に設定されている主軌道補間点の数を計算し直す。すなわち、溶接トーチ１４の教示点間の移動距離を教示点間距離Ｄｔに一致させるために、予め教示データから求められている残存距離Ｄｒ中の主軌道補間点の数を、残存距離Ｄｒとアダプティブ速度Ｖａとに応じて変更する。残存距離Ｄｒ中の主軌道補間点数ｎｒは、補間周期Ｔｉを用いて以下のように求められる。

Then, the number of main trajectory interpolation points set in the remaining distance Dr is recalculated from the remaining distance Dr between the teaching points and the adaptive speed Va. That is, in order to make the movement distance between the teaching points of the welding torch 14 coincide with the teaching point distance Dt, the number of main trajectory interpolation points in the remaining distance Dr previously obtained from the teaching data is set to the remaining distance Dr and the adaptive distance. It changes according to speed Va. The number nr of main trajectory interpolation points in the remaining distance Dr is obtained as follows using the interpolation cycle Ti.

これにより、アダプティブ速度Ｖａが変更されて主軌道補間点間距離Ｄｐが変化する場合においても、残存距離Ｄｒ中の主軌道補間点数ｎｒを変更することで、溶接トーチ１４の教示点間の移動距離と教示点間距離Ｄｔとを一致させることができる。すなわち、アダプティブ速度Ｖａが低下する場合には、主軌道補間点数ｎｒを増加させ、アダプティブ速度Ｖａが上昇する場合には、主軌道補間点数ｎｒを減少させることにより、実際の溶接トーチ１４の教示点間の移動距離を教示点間距離Ｄｔに合わせることができる。

Thereby, even when the adaptive speed Va is changed and the distance Dp between the main trajectory interpolation points changes, the moving distance between the teaching points of the welding torch 14 is changed by changing the number nr of main trajectory interpolation points in the remaining distance Dr. And the teaching point distance Dt can be made to coincide with each other. That is, when the adaptive speed Va decreases, the main trajectory interpolation point number nr is increased, and when the adaptive speed Va increases, the main trajectory interpolation point number nr is decreased to thereby reduce the teaching point of the actual welding torch 14. The moving distance between them can be matched with the distance Dt between teaching points.

When the main trajectory interpolation point calculation processing unit 28 obtains the main trajectory interpolation point number nr in the remaining distance Dr, the main trajectory interpolation point calculation processing unit 22 of the robot control unit 21 calculates a new main trajectory interpolation point from the main trajectory interpolation point nr. Calculate points. Here, the main trajectory interpolation point calculation processing unit 28 and the main trajectory interpolation point calculation processing unit 22 correspond to interpolation point recalculation means. Then, based on the new main trajectory interpolation point, the scanning correction is performed in the same procedure as in the first embodiment. Incidentally, the adaptive speed Va, together with the current position and orientation of the main track interpolation point, based on the serial ID of the first buffer 26, together with the serial number assigned to the corresponding main track interpolation point, temporarily in the second buffer 2 7 Remembered.

  Further, when Rp is equal to or greater than 1 in Expression (17), the interpolation operation between the teaching points is completed, and therefore the robot control unit 21 performs the processing of the interpolation operation between the next teaching points. The change in the number of main trajectory interpolation points nr as described above is performed every time the adaptive speed Va is changed.

  Next, control of the positioner 71 and the slider 72 performed by the robot control unit 21 will be described. The robot control unit 21 performs the same control as the control on the welding torch 14 for the positioner 71 and the slider 72 when the adaptive welding function is applied and the adaptive speed Va is changed. That is, the robot control unit 21 presets the interpolation points of the positioner 71 and the slider 72 corresponding to the main trajectory interpolation points of the welding torch 14 from the teaching data (movement data). When the adaptive speed Va is changed, the positioner 71 and the slider are calculated from the product of the total movement amount such as the total movement distance or the total movement angle between the teaching points and the main trajectory digestion rate Rp obtained by the equation (17). The remaining movement amount between the 72 teaching points is calculated. Next, the number of interpolation points in the remaining movement amount is obtained by the same method as equation (19), and a new interpolation point is calculated. As described above, the robot control unit 21 serving as the corresponding interpolation point calculating means corresponds to the newly calculated main trajectory interpolation point of the welding torch 14 when the adaptive speed Va is changed, and the positioner 71 and the slider 72. Are newly calculated. As described above, since the main track digestion rate Rp of the welding torch 14 and the main track digestion rate of the positioner 71 and the slider 72 are equal, the positioner 71 and the slider 72 are connected to the welding torch 14 while performing adaptive speed control. The operation can be performed with the synchronized motion control synchronized with the teaching distance, and the relative posture between the welding torch 14 and the workpiece W can be maintained in accordance with the teaching posture.

  The operation of the welding torch 14 and the positioner 71 when welding is performed on the same workpiece W as in FIG. 10 by the above control will be described. The welding torch 14 starts moving from the position WA as shown in FIG. When the welding torch 14 moves, the scanning correction of the welding torch 14 is performed based on the detection result of the laser sensor 31, but the control device 2 determines that the main trajectory interpolation point is based on the correction deviation amount as shown in the first embodiment. Therefore, the position error in the main trajectory direction can be suppressed. Even if the moving speed of the welding torch 14 changes due to the action of the adaptive welding function, the number nr of the main trajectory interpolation points is changed by the equation (19), so the moving distance between the teaching points of the welding torch 14 Can be matched with the distance Dt between teaching points. For this reason, when the welding torch 14 reaches the position WB advanced by the teaching distance, the rotational motion of the positioner 71 is started.

  Then, when the welding torch 14 moves from the position WB to the position WD, the welding torch 14 and the positioner 71 operate together, and synchro motion control is performed. At this time, even if the adaptive welding function acts and the moving speed of the welding torch 14 may change, the main track digestion rate of the positioner 71 and the main track digestion rate of the welding torch 14 become equal. It operates in synchronization with the teaching distance of the welding torch 14. For this reason, as shown in FIG. 10B, even when the welding torch 14 faces the position WC in the middle of rotation of the positioner 71, the receding angle of the welding torch 14 can be set to 0 °. Therefore, it is possible to prevent the occurrence of poor welding due to the welding torch 14 having a receding angle which is not given by teaching.

  Then, as shown in FIG. 10C, when the welding torch 14 reaches the position WE, the linear movement of the welding torch 14 is finished, and the work W welding process is finished. In this way, the welding length as set in the teaching can always be realized even if adaptive speed control is performed. The control device 2 controls the operation of the welding torch 14 and the positioner 71 in this way, thereby suppressing the position error generated in the traveling direction of the welding torch 14 and synchronizing the positioner 71 with the teaching distance of the welding torch 14. Make it work. Of course, it goes without saying that the slider 72 is operating synchronously at this time.

According to the welding robot control device 2 of the second embodiment, the following effects can be obtained.
(3) In the second embodiment, when the adaptive welding function is activated and the adaptive speed Va is changed, the control device 2 calculates the main track digestion rate Rp from the teaching point distance Dt, and between the teaching points. The remaining distance Dr is obtained. Then, the number of main trajectory interpolation points nr in the remaining distance Dr is recalculated from the remaining distance Dr between the teaching points and the adaptive speed Va to calculate a new main trajectory interpolation point. For this reason, even when the adaptive speed Va is changed and the distance Dp between the main trajectory interpolation points is changed, the moving distance between the teaching points of the welding torch 14 is changed by changing the number nr of main trajectory interpolation points in the remaining distance Dr. And the distance Dt between teaching points can be matched, and the actual welding length can be adjusted to a preset welding length.

  (4) In the second embodiment, the control device 2 uses the interpolation points of the positioner 71 and the slider 72 corresponding to the newly calculated main trajectory interpolation point of the welding torch 14 when the adaptive speed Va is changed. Is newly calculated. For this reason, it is possible to prevent the positioner 71 and the slider 72 from continuing to move in accordance with preset teaching data even though the moving speed of the welding torch 14 is changed. In addition, the synchronized motion can be controlled by synchronizing the operation with the slider 72. Accordingly, it is possible to prevent the relative position and posture between the welding torch 14 and the workpiece W from deviating from the preset relative position and posture. The deviation of the attitude of the welding torch 14 relative to the workpiece W can be suppressed. Thereby, it is possible to prevent the occurrence of poor welding due to the fact that the actual welding length does not coincide with the preset welding length due to the deviation in the main track direction and the welding torch 14 has a receding angle not given by the teaching.

(Third embodiment)
Next, a third embodiment in which the robot control device according to the present invention is applied to a welding robot control device will be described with reference to FIG. In the control device of the third embodiment, the configuration of the manipulator 11, the robot control unit 21, the laser sensor 31, the sensor control unit 41, and the welding power source 51 is the same as that of the first embodiment, and the control device uses the work W as one axis. The point which is provided with the positioner moved to a direction differs from a 1st embodiment. In the embodiments described below, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions thereof are omitted or simplified.

FIG. 13 is a block diagram showing the configuration of the control device 3 for the welding robot according to the third embodiment. The control device 3 includes a positioner 61 that moves the workpiece W. The positioner 61 rotates the workpiece W around the rotation shaft 62 to move the workpiece W in one axial direction (traveling direction R) with respect to the welding torch 14. The rotating shaft 62 is driven by a motor (not shown). The robot controller 21 of the control device 3 controls the movement of the positioner 61 by performing drive control of the motor. Further, the welding torch 14 of the manipulator 11 is disposed at the apex of the workpiece W, and the operation thereof is controlled by the robot control unit 21.

  The robot control unit 21 moves the workpiece W in the traveling direction R by the positioner 61 and moves the welding torch 14 in a plane (groove plane) perpendicular to the traveling direction R, so that the positioner 61 and the welding torch 14 are moved. Synchro motion control is performed and the workpiece W is positioned. Such synchro motion control is performed based on preset teaching data.

  The scanning correction by the control device 3 is performed in the same procedure as that of the control device 1 of the first embodiment. That is, the current position calculation processing unit 25 of the robot control unit 21 calculates the current position and posture of the welding torch 14 and transmits the calculated current position and posture to the sensor control unit 41. The sensor control unit 41 sets the target position and posture of the welding torch 14 by comparing the current position and posture with the shape detection result of the workpiece W by the laser sensor 31. The scanning correction processing unit 23 performs scanning correction based on the target position and posture.

  At this time, the scanning correction processing unit 23 does not perform scanning correction in the traveling direction R, but only performs scanning correction in the groove plane. That is, the scanning correction processing unit 23 performs only correction for the movement of the welding torch 14 in the groove plane, and ignores the correction for the movement of the welding torch 14 in the traveling direction R and the correction of the movement of the positioner 61. For this reason, even when the correction value for the traveling direction R is calculated, the robot control unit 21 serving as a control unit prohibits the movement of the welding torch 14 in the traveling direction R and the preset welding torch 14. Control is performed to rotate the positioner 61 in synchronization with the teaching distance. As described above, if only the scanning correction in the groove plane is performed without performing the scanning correction in the traveling direction R, the position error in the traveling direction R generated by the scanning correction can be suppressed.

According to the welding robot control device 3 of the third embodiment, the following effects can be obtained.
(5) In the third embodiment, the control device 3 controls the movement of the welding torch 14 and the positioner 61 while ignoring the scanning correction in the traveling direction R when performing scanning correction. For this reason, it is possible to suppress the deviation in the traveling direction R caused by the scanning correction, that is, the position error, and the actual working track length by the scanning correction becomes shorter than the preset working track length of the welding torch 14. Such a situation can be avoided.

In addition, you may change the said embodiment as follows.
In the first to third embodiments, as the sensor for detecting the shape of the workpiece W, the scanning type laser sensor 31 that measures the distance to the workpiece W by light emission and light reception of the laser is used. A contact type sensor may be used, or a contact type sensor may be used. In addition, this sensor may not be a distance sensor that measures the distance to the workpiece W as long as the shape of the workpiece W can be detected.

  In the first to third embodiments, control in the control devices 1, 2, and 3 is performed by the robot control unit 21 and the sensor control unit 41, but one control unit collectively Control may be performed, or control may be performed in a different manner.

  In the first to third embodiments, the robot control device according to the present invention is applied to the welding robot. However, any robot other than the welding robot can be used as long as the robot executes the work after detecting the shape of the workpiece W. You may apply to an industrial robot.

  In the first embodiment, the robot control unit 21 corrects the position and orientation of the welding torch 14 based on the correction deviation amount, but the error I as shown in FIG. 6B is minimal. When it is determined that the amount of deviation is not converted from the deviation amount to the corrected deviation amount, the copying correction may be performed based on the deviation amount.

  In the second embodiment, the positioner 71 and the slider 72 are used as moving means for moving at least one of the workpiece W and the manipulator 11 along preset teaching data, but either the positioner 71 or the slider 72 is used. Only one of them may be used.

  In the second embodiment, when the adaptive speed Va is changed, the number of main trajectory interpolation points nr is changed so that the movement distance between the teaching points of the welding torch 14 matches the distance Dt between the teaching points. However, the interpolation cycle Ti may be changed without changing the number of main trajectory interpolation points nr so that the movement distance between the teaching points of the welding torch 14 matches the distance Dt between the teaching points.

The block diagram which shows the structure of the control apparatus of the welding robot which concerns on 1st Embodiment. The schematic block diagram of a laser sensor. Two-dimensional data of the workpiece measured by the laser sensor. Schematic which shows the three-dimensional track | orbit produced | generated from the feature point of a workpiece | work. The block diagram of a robot control part and a sensor control part. (A) is a figure which shows the position of the main trajectory interpolation point produced | generated by the main trajectory interpolation point calculation process part, (b) is a figure which shows the position of the main trajectory interpolation point when scanning correction is carried out. The figure which shows the deviation | shift amount calculated by a scanning correction process part in a reference | standard coordinate system and a main orbit coordinate system. (A) is a figure which shows the position of the main trajectory interpolation point produced | generated by the main trajectory interpolation point calculation process part, (b) is a figure which shows the position of the main trajectory interpolation point when copying is corrected based on the amount of correction deviation. . The block diagram which shows the structure of the control apparatus of the welding robot which concerns on 2nd Embodiment. (A), (b), (c) is a schematic diagram showing a welding process. (A), (b), (c) is a comparison figure which shows an example of the welding state in the welding process of FIG. The block diagram of a robot control part and a sensor control part. The block diagram which shows the structure of the control apparatus of the welding robot which concerns on 3rd Embodiment. The block diagram which shows the structure of the control apparatus of the welding robot in a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2, 3 ... Control apparatus, 11 ... Manipulator, 14 ... Welding torch, 21 ... Robot control part, 22 ... Main track interpolation point calculation process part, 23 ... Copying correction process part, 25 ... Current position calculation process part, 26 DESCRIPTION OF SYMBOLS 1st buffer, 27 ... 2nd buffer, 28 ... Main orbit interpolation point number calculation process part, 31 ... Laser sensor, 41 ... Sensor control part, 51 ... Welding power supply, 61, 71 ... Positioner, 72 ... Slider.

Claims (6)

A work tool provided in the robot, and a sensor mounted on the work tool and detecting the shape of the work object prior to the work, the position of the work tool on a preset main trajectory, and A robot control device that operates the work tool along a plurality of main trajectory interpolation points indicating a posture, and corrects the main trajectory interpolation points based on an output of the sensor,
Current position calculating means for calculating the current position and orientation of the work tool corresponding to the main trajectory interpolation point;
Storage means for storing the calculated current position and orientation together with a serial number assigned to the corresponding main trajectory interpolation point;
Target position setting means for setting the target position and posture of the work tool set based on the calculated current position and posture and the output of the sensor together with the serial number assigned to the corresponding main trajectory interpolation point When,
Before Symbol set target position and orientation, to calculate the amount of deviation between those the set target position and orientation between the current position and orientation stored in the storage means associated with each other by the serial number, A robot control comprising: a correction unit that corrects , based on the deviation amount, a main trajectory interpolation point corresponding to a serial number used in calculating the deviation amount based on the deviation amount. apparatus.   The correction means calculates a correction deviation amount obtained by removing a component in the main trajectory direction from the deviation amount, and corrects the operation of the work tool based on the correction deviation amount. Robot control device. An adaptive function for changing work conditions including at least the moving speed of the work tool according to the shape of the work object detected by the sensor during work of the work tool;
When the moving speed of the work tool is changed by the adaptive function, the number of main trajectory interpolation points set on the main trajectory prior to the operation of the work tool is changed based on the moving speed, The robot control apparatus according to claim 1, further comprising: an interpolation point recalculation unit that calculates a new main trajectory interpolation point. Moving means for moving at least one of the work object and the robot along movement data set in advance during work of the work tool;
Corresponding interpolation for newly calculating the interpolation point of the movement data corresponding to the new main trajectory interpolation point calculated by the interpolation point recalculation means when the moving speed of the work tool is changed by the adaptive function The robot control device according to claim 3, further comprising point calculation means. A positioner for moving the work object in one axial direction with respect to the work tool;
5. The apparatus according to claim 1, further comprising: a control unit that controls the operation of the work tool and the positioner while ignoring correction with respect to the movement direction of the positioner based on the output of the sensor. The robot control device according to the item.   The robot control apparatus according to claim 1, wherein the sensor is a scanning laser sensor that measures a distance to a work object by emitting and receiving light of a laser.

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