JP2011110688A - Robot teaching device and robot control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot teaching device and a robot control device, which reduce a burden of teaching work by a worker, by eliminating the initial setting work of the worker within the operation range of a robot and the allowable range of force-sensitive sensor output required for each kind of part. <P>SOLUTION: A passage teaching system 127 allows a robot hand 102 to perform an extraction operation of an installation work 140, while searching the positional attitude of the robot hand 102 which does not apply an excessive force working on the installation work 140, by allowing the robot hand 102 to grip the installation work 140 installed to an installation object work 150. The passage teaching system 127 acquires the extracting moving passage of the robot hand 102 in its extraction operation. The passage teaching system 127 generates a passage of following the acquired extracting moving passage in time series inverse order as an installation work passage, and teaches its generated installation work passage to an operation control part 121. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a robot teaching apparatus having a function of acquiring a work path (working trajectory) of an articulated robot whose position and orientation can be changed, and a robot control apparatus.

  In general, in order to make a robot having a robot hand perform a desired work, the position / posture (position, height, and position) in a scene where the behavior of the robot changes such as the start posture, intermediate posture, and end posture of the work path. Teaching to define (tilt) is required. In particular, in assembling work involving contact between workpieces, it is necessary to accurately teach the position and orientation in each scene in order to reduce insertion errors.

  Here, a general robot teaching operation will be described. First, an operator moves the robot hand to a desired position and orientation using a teaching box connected to the control device, and stores data indicating the position and orientation on the robot program. Then, it causes the control device to calculate operation commands to a plurality of servo motors that satisfy a path (orbit) that connects these positions and orientations.

  For example, in a general work definition for assembly work, an operator uses a teaching box to teach the assembly start position and assembly end position, and the robot hand appropriately defines instructions to move between teaching points. By doing so, a robot program relating to the assembly work is defined. For the movement of the robot hand from the assembly start position to the assembly end position, a movement command is generally defined so that the finger part (or assembly work) of the robot hand draws a straight line. When assembling the assembled work to the work to be assembled while changing the posture of the assembled work in the middle of the assembling work, set a via point between the assembling start position and the assembling end position and posture as appropriate. Need to add.

  In the robot teaching work as described above, the visual teaching work by the worker is a time-consuming and difficult task, and the worker often cannot secure a good field of view. Therefore, the control device detects the contact state between the robot and the component via a force sensor (force detection means) attached to the wrist or joint of the robot, or a component jig, etc. A technique for performing control according to a contact state is known.

  As an example of such a technique, in the conventional robot teaching apparatus as shown in Patent Document 1, after the operator has taught the position and orientation at the start of assembly work as preliminary teaching relatively coarsely, The robot controller performs automatic operation by force control. During this automatic operation, the robot controller stores information on the position and orientation of the robot hand at the start and end of assembly when the assembly operation is successful. Used in place of the information defined by.

  As a technique other than the conventional apparatus shown in Patent Document 1, for example, there is an automatic teaching method and apparatus for an assembly robot as shown in Patent Document 2. In this device, the driving device moves the robot to the vicinity of the assembly start position using geometric data such as CAD and a signal from the non-contact sensor. Thereafter, the drive device performs final adjustment of the assembly start position in accordance with a signal from the contact sensor. The teaching point determination means stores the position when the final adjustment is completed as the teaching point.

JP-A-8-194521 JP-A-9-146624

  In the conventional device as shown in Patent Document 1 above, in order to realize the assembly work by force control, sensor calibration (force sensor adaptation work), operation range for moving the robot safely, force Initial setting work such as setting the permissible range of the sensor output is required. In particular, during robot force control, if the amount of movement or posture change of the robot in a direction other than the assembly direction is relatively large, the posture (work It is difficult to perform the initial setting work for the robot movement range for prohibiting a posture that cannot be expected to be successful or a posture that may cause a risk of interference with other devices.

  Also, in assembly work that requires the workpiece to be pushed in, a large reaction force is generated on the workpiece even during normal assembly operation, resulting in abnormal assembly conditions and abnormalities such as biting. It is difficult to set an allowable range of the force sensor output for distinguishing from the assembled state.

  Therefore, in the conventional device as shown in Patent Document 1, it is necessary to accurately set the robot operation range and the force sensor output allowable range at the initial setting stage. The parts that depended on the experience of the workers were large. That is, the initial setting work has a problem that the number of workers is limited and a worker who has experience is restricted for a long time.

  The present invention has been made to solve the above-described problems, and omits the initial setting work of the operator regarding the robot operation range and the allowable range of the force sensor output required for each component type. An object of the present invention is to provide a robot teaching device and a robot control device that can reduce the burden of teaching work by an operator.

  The robot teaching device of the present invention can detect the position and orientation of the robot hand, insert the assembly work into an insertion portion provided in the assembly work, and place the assembly work on the assembly work. A path teaching unit that teaches an operation control unit that controls an operation of the robot hand, an assembly work path that is a movement path of the robot hand at the time of assembly; Causing the robot hand holding the assembly work assembled to the attachment work in advance to perform a drawing operation of the assembly work in a preset drawing direction, and the robot hand A pull-out movement path that minimizes the reaction force generated in the assembled workpiece by gripping the workpiece is searched using a signal from the force detection means for detecting the reaction force generated in the assembled workpiece. Is intended to teach the operation controller time series reverse order of the searched the drawing movement path as the assembling work path.

  According to the robot teaching apparatus of the present invention, the path teaching unit acquires the assembly work path from the pulling movement path searched during the pulling operation by the robot hand and teaches it to the operation control unit. The robot hand does not take a posture that causes the assembly work to fail, and the completion of the assembly work is not judged based on the reaction force of the assembly work in the pulling direction. The operator's initial setting work regarding the permissible range of the sense sensor output can be omitted, and the burden of teaching work by the worker can be reduced.

It is a block diagram which shows the robot by Embodiment 1 of this invention. It is explanatory drawing for demonstrating the detection axis | shaft of the force sensor of FIG. It is a block diagram which shows the control apparatus main body of FIG. 1 more concretely. It is a flowchart which shows the teaching process of the path | route teaching system of FIG. It is sectional drawing which shows the initial state of the robot hand in extraction operation | movement. It is sectional drawing which shows the holding state of the robot hand in extraction operation | movement. It is sectional drawing which shows the to-be-assembled work jig | tool and force sensor by Embodiment 2 of this invention. It is a block diagram which shows the control apparatus of the robot by Embodiment 3 of this invention. It is sectional drawing which shows an example of the assembly | attachment state of the assembly work by Embodiment 3 of this invention, and a to-be-assembled work. It is a graph which shows the change of the output of the force sensor by Embodiment 3 of this invention. It is sectional drawing which shows the other example of the assembly | attachment state of the assembly | attachment workpiece | work and to-be-assembled workpiece | work by Embodiment 3 of this invention. It is a block diagram which shows the control apparatus of the robot by Embodiment 4 of this invention. It is explanatory drawing for demonstrating the coordinate system used with the offline programming apparatus of FIG. It is a flowchart which shows the teaching process of the path | route teaching system by Embodiment 5 of this invention. It is a graph which shows the change of the output of the force sensor by Embodiment 5 of this invention. It is a block diagram which shows the control apparatus of the robot by Embodiment 6 of this invention. It is a graph which shows the change of the output of the force sensor by Embodiment 6 of this invention. It is explanatory drawing for demonstrating an example of the display state of the display information which the control apparatus of the robot by Embodiment 7 of this invention produced | generated.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
1 is a block diagram showing a robot according to a first embodiment of the present invention.
In FIG. 1, a robot 100 is a vertical articulated robot. In addition, the robot 100 performs the assembly work of the assembly work 140 and the work to be assembled 150. As shown in FIG. 2, the assembling work is an operation of inserting the assembling work 140 into the inserted portion 150 a provided in the assembling work 150 and assembling the assembling work 140 into the assembling work 150. It is.

  The robot 100 has a robot arm 101 and a robot hand 102. The robot hand 102 is provided on the wrist portion of the robot arm 101. The robot hand 102 has a pair of finger portions arranged to face each other. In addition, the robot hand 102 can grip (hold / grip) the assembled workpiece 140 by the pair of finger portions sandwiching the assembled workpiece 140 from the side thereof.

  A servo motor for changing the position and orientation of the robot arm 101 and an encoder for detecting the drive amount of the servo motor are attached to each of the plurality of joints of the robot arm 101 (all are not shown). ) A force sensor 110 as a force detection means is attached to the wrist of the robot arm 101. The force sensor 110 is a sensor for detecting a reaction force (stress / strain) generated on an object in contact with the robot hand 102.

  Specifically, as shown in FIG. 2, the force sensor 110 includes a force component (X axis, Y axis, Z axis) in the three translational directions and a moment component (Rx, Ry, Rz), that is, a signal of 6-axis component values is generated. Note that the coordinate system shown in FIG. 2 is a coordinate system associated (fixed) with the work space in which the robot 100 is provided. Moreover, in the example of FIG. 2, the upper direction of FIG. 2 is the drawing direction, and the Z axis along the drawing direction is the first translation axis. The X axis orthogonal to the Z axis is the second translation axis, and the Y axis orthogonal to both the X axis and the Z axis is the third translation axis.

  The operation of the robot 100 is controlled by the control device main body 120. The control device main body 120 detects a reaction force generated on an object in contact with the robot hand 102 via the force sensor 110. Further, the control device main body 120 can detect the position and orientation of the robot hand 102 by monitoring the position and orientation (position, height, and tilt) of the robot hand 102 via the encoder of the robot arm 101.

  Further, the control device main body 120 can be configured by hardware (not shown) having an arithmetic processing unit (CPU), a storage unit (ROM, RAM, hard disk, etc.) and a signal input / output unit. The control device main body 120 receives a robot program defining a predetermined operation from, for example, a general-purpose computer (not shown) and stores it in advance.

  Furthermore, the control device main body 120 controls the operation of the robot 100 based on a robot program stored in advance. In addition, the control device main body 120 controls the operation of the robot 100 in accordance with a movement command from an operator input via the teaching box (manual operation panel) 130.

  Here, the robot program stored in the control device main body 120 will be described. This robot program is a list of specific coordinate values indicating the position and orientation of the robot hand 102 (hand). The control device main body 120 temporarily stores the robot program received from the general-purpose computer in the storage unit, and then reads out the coordinate values of the robot program in order from the top. Then, after reading the coordinate values in order, the control device main body 120 drives the servo motor of the robot arm 101 so that the robot hand 102 reaches the coordinate values in order, and a plurality of links that form the robot arm 101. Rotate.

  Such a robot program is described in a structured programming grammar using conditional branches, repetitions, subroutines, functions, procedures, and the like, and a robot language in which command words for operating the robot 100 are combined. Can be used.

  Further, the control device main body 120 acquires information on the six-axis component values (hereinafter also referred to as “output of the force sensor 110”) from the force sensor 110, and the six-axis component values are constant, for example. The coordinate value of the robot hand 102 is calculated, and the coordinate value of the next movement destination of the robot hand 102 is generated. Thereby, the control device main body 120 acquires the six-axis component value from the force sensor 110, calculates the movement amount of the robot hand 102 based on a predetermined calculation using the acquired six-axis component value, and moves the robot hand 102. A series of control loops (that is, a series of operations of the route teaching system 127) of generating the previous coordinate values and moving the robot hand 102 can be executed.

  Next, FIG. 3 is a block diagram showing the control device main body 120 of FIG. 1 more specifically. In FIG. 3, the control device main body 120 automatically generates an assembly work path by defining an assembly start position, an assembly end position, and a posture change position during the assembly work as necessary. Further, in the control device main body 120, information on the pulling direction of the assembly work 140 and information on the target position regarding the pulling operation of the robot hand 102 are set in advance. The control device main body 120 includes an operation control unit 121, a position / orientation search unit 122, a drawing position / orientation generation unit 123, a target position arrival determination unit 124, a force sensor output determination unit 125, and a work path generation unit 126. Yes.

  The position / orientation search unit 122, the extraction position / orientation generation unit 123, the target position arrival determination unit 124, the force sensor output determination unit 125, and the work route generation unit 126 constitute a route teaching system 127 as a route teaching unit. The route teaching system 127 teaches to the operation control unit 121 an assembly work route that is a movement route of the robot hand 102 when the assembly workpiece 140 is assembled to the assembly workpiece 150. Further, when teaching the assembly work route to the operation control unit 121, the route teaching system 127 sends an operation command to the operation control unit 121 to change the position and orientation of the robot hand 102.

  The operation control unit 121 has a function related to operation control of the robot 100 in the control device main body 120. The position / orientation search unit 122 can execute a search process for the drawing start position / orientation (optimum position / orientation) of the robot hand 102. The pulling start position / posture means that the position of the assembled work 140 in the pulling direction does not change and other than the pulling direction of the assembled work 140 (directions other than the Z direction in FIG. 2, ie, X, Y, Rx, Ry, and Rz) The position and orientation at which the output of the force sensor 110 in each direction is minimized (sufficiently small). This drawing start position / posture is the starting point of the drawing movement path and the end point of the assembly work path.

  The drawing position / posture generation unit 123 calculates the position / posture (position, height, and angle) of the robot hand 102 for moving the assembly work 140 by a certain amount only in the Z direction (drawing direction), and the calculated coordinates. The robot hand 102 is moved toward the value. The target position arrival determination unit 124 determines whether or not the robot hand 102 has reached a drawing end position as a preset target position during the drawing operation of the robot hand 102. Further, when it is confirmed that the robot hand 102 has arrived, the target position arrival determination unit 124 stores the position and orientation of the robot hand 102 at that time as the drawing end position and orientation. This drawing end position / posture is the end point of the drawing movement path and the starting point of the assembly work path.

  The force sensor output determination unit 125 sets the output (initial value) of the force sensor 110 in an initial state (a state in which the robot hand 102 is opened) as a reference value (= 0) when the robot hand 102 is pulled out. Set. Further, the force sensor output determination unit 125 monitors the absolute value of the output of the force sensor 110 during the pulling operation of the robot hand 102, that is, the relative value from the reference value set in the initial state. Based on the absolute value of the output of the force sensor 110, it is determined whether or not to change the posture of the robot hand 102 during the extraction operation.

  Further, when the force sensor output determination unit 125 determines to change the posture of the robot hand 102 during the pulling-out operation, the force sensor output determination unit 125 causes the position / orientation search unit 122 to execute a search process. The work route generation unit 126 connects the positions and orientations of the robot hand 102 stored by the position and orientation search unit 122 and the target position arrival determination unit 124 in reverse order in time series, and generates an assembly work route for the robot hand 102.

  Next, an example of the assembly position / posture search process by the position / posture search unit 122 will be described. First, the position / orientation search unit 122 moves the robot hand 102 by a minute amount dx in the X-axis direction, and acquires the change amount ΔF of the output of the force sensor 110 as a five-dimensional vector other than the Z-axis direction. That is, the amount of change ΔF is the amount of change ΔFx, ΔFy in the output of the force sensor 110 in the X and Y axis directions and the amount of change ΔMx, ΔMy, in the output of the force sensor 110 for the rotation Rx, Ry, Rz of each axis. It is determined by five elements, ΔMz.

  Then, the position / orientation search unit 122 calculates a vector ΔF / dx obtained by dividing each element of the variation ΔF by dx. Similarly, the position / orientation search unit 122 moves the robot hand 102 by the minute amounts dy, dRx, dRy, and dRz in the Y, Rx, Ry, and Rz directions, respectively, to obtain vectors ΔF / dy, ΔF. / DRx, ΔF / dRy, and ΔF / dRz are calculated.

  That is, the position / orientation search unit 122 translates along the X axis and the Y axis orthogonal to the Z axis along the pull-out direction and to the X axis, the Y axis, and the Z axis. The robot hand 102 holding the assembly work 140 is caused to execute this rotational movement. Here, if the movement amount of the robot hand 102 is relatively small, ΔF / d * (where * = x, y, Rx, Ry, Rz) has a linear characteristic. As a result, the position / orientation search unit 122 calculates the movement amount of the robot hand 102 in which the outputs other than the Z direction among the outputs of the current force sensor 110 are 0 by solving the simultaneous equations of five variables.

  Subsequently, the position / orientation search unit 122 moves the robot hand 102 by the calculated movement amount of the robot hand 102. Then, the position / orientation search unit 122 determines whether the output of the force sensor 110 is the minimum value (≈0) or the absolute value of the output of the force sensor 110 is the position / orientation of the robot hand 102 after the movement. When it is confirmed that it has not increased from the reference value (it is sufficiently small), the current position / posture of the robot hand 102 is stored as the drawing start position / posture.

  Accordingly, the position / orientation search unit 122 sets the output of the force sensor 110 as a reference value in a state where the robot hand 102 is opened (in a state where the assembly work 140 is not gripped) as a previous stage of the search process. Then, the position / orientation search unit 122 is based on the absolute value of the output of the force sensor 110 (the absolute value of the output of each axis other than the Z-axis direction) in a state where the robot hand 102 is holding the assembly workpiece 140. The robot hand 102 holding the assembly work 140 is moved in each direction so as to be equal to the value (so as to be sufficiently small). The position / orientation search unit 122 stores the position / orientation of the robot hand 102 at which the output of the force sensor 110 is minimized as the extraction start position / orientation.

  Next, a series of operations of the teaching process of the route teaching system 127 will be described. FIG. 4 is a flowchart showing the teaching process of the route teaching system 127 of FIG. FIG. 5 is a cross-sectional view showing an initial state of the robot hand 102 in the pulling-out operation. FIG. 6 is a cross-sectional view showing a gripping state (clamping state) of the robot hand 102 in the pulling-out operation.

  First, as shown in FIG. 5, a situation in which the assembly work 140 is assembled to the work to be assembled 150 (a situation in which a desired assembly work between the works has been completed) is prepared in advance by an operator. Then, the robot hand 102 is moved to a position where the assembly work 140 can be gripped by manual operation of the teaching box 130 of the operator or the like. The position and orientation of the robot 100 at this time is the teaching start position and orientation. In this state, the robot hand 102 and the assembly work 140 do not have to face each other.

  Subsequently, the robot hand 102 is closed as shown in FIG. 6 by a manual operation or the like by an operator, and grips the assembly work 140. At this time, the force sensor 110 generates a signal corresponding to the reaction force generated in the assembly work 140. In the state shown in FIG. 6, the posture of the robot hand 102 and the assembly work 140 is not opposed to each other. Therefore, the assembly is performed as compared with the case where the posture of the robot hand 102 and the assembly work 140 is opposed. The reaction force generated in the workpiece 140 increases, and the absolute value of the output of the force sensor 110 changes from the reference value in an increasing direction.

  In FIG. 4, the position / orientation search unit 122 detects that the absolute value of the output of the force sensor 110 has changed from the reference value in the increasing direction (step S101). Thereafter, the position / orientation search unit 122 causes the robot hand 102 to execute translational motion and rotational motion (step S102).

  At this time, the position / orientation search unit 122 monitors fluctuations in the output of the force sensor 110 other than the Z direction accompanying the translational motion and the rotational motion of the robot hand 102, and the absolute value of the output of the force sensor 110 is minimized. The position and orientation of the robot hand 102 is searched (step S103). Then, when the position and orientation search unit 122 detects the position and orientation of the robot hand 102 whose relative value from the reference value (= 0) is sufficiently small with respect to the absolute value of the output of the force sensor 110, the position and orientation of the robot hand 102 is detected. Is stored as the drawing start position / posture P0 (step S104).

  After the position / orientation search unit 122 searches and stores the drawing start position / posture P0, the drawing position / posture generation unit 123 calculates the position / posture of the robot hand 102 for moving the assembly work 140 by a certain amount only in the Z direction. Then, a movement command is sent to the operation control unit 121 to move the robot hand 102 by a certain amount only in the Z direction (step S105).

  Here, in the above description, the Z direction of the coordinate system shown in FIG. 2 is defined as the pulling direction of the assembly work 140, but the robot hand 102 accurately holds the assembly work 140 (assembly work 140). The coordinate direction between the coordinate system of the robot hand 102 and the coordinate system of the robot hand 102 is always constant), and the drawing direction of the assembly work 140 can be defined based on the coordinate system of the robot hand 102.

  In the following description, it is assumed that the robot hand 102 accurately holds the assembly work 140 after the search for the drawing start position / posture P0 is completed, and the coordinate system of the assembly work 140 and the coordinate system of the robot hand 102 are assumed. The coordinate transformation between and is always constant. However, the pulling direction of the assembling work 140 is not necessarily defined in the work coordinate system, for example, when pulling out in a certain direction while changing the posture of the assembling work 140. In this case, the drawing direction of the assembled work 140 is not a fixed direction based on the coordinate system of the assembled work 140 or the coordinate system of the robot hand 102.

  When the drawing position / posture generation unit 123 moves the robot hand 102 in the Z direction, the target position arrival determination unit 124 monitors the position / posture of the robot hand 102 and determines whether the robot hand 102 has reached the target position. Is determined (step S106). This determination is made based on, for example, whether or not the robot hand 102 has reached a height sufficient to pull out the assembly workpiece 140. In other words, the target position arrival determination unit 124, with the robot hand 102 gripping the assembly work 140, from the upper surface of the assembly work 150, is set to a preset height (the height dimension of the assembly work 140 or higher). Judgment is made based on whether the height is reached.

  When the target position arrival determination unit 124 determines that the target position has not been reached (NO direction in step S106), the force sensor output determination unit 125 outputs the output of the force sensor 110 other than the Z direction. It is determined whether or not the absolute value has increased from the reference value (or whether or not the absolute value of the sensor output is sufficiently small) (step S107). When the force sensor output determination unit 125 confirms that the output of the force sensor 110 is equal to the reference value (NO direction in step S107), the drawing position / posture generation unit 123 again moves the robot hand in the Z direction. 102 is moved (step S105). At the same time, the target position arrival determination unit 124 determines whether or not the robot hand 102 has reached the target position (step S106).

  On the other hand, when the force sensor output determination unit 125 confirms that the absolute value of the output of the force sensor 110 other than the Z direction has increased from the reference value (or that the absolute value of the sensor output is not sufficiently small). (YES direction in step S107), the position / orientation search unit 122 makes the absolute value of the output of the force sensor 110 (the reaction force generated in the assembled workpiece 140) the minimum at the position of the robot hand 102 at that time. Is searched for (step S108). The position / orientation search process of the position / orientation search unit 122 at this time is the same as the search process for the extraction start position / orientation P0.

  If the position / orientation search unit 122 detects the position / orientation of the robot hand 102 at which the absolute value of the output of the force sensor 110 is minimized at the position of the robot hand 102 at this time, the position / orientation search unit 122 determines that the position / orientation / interval The posture is stored as P1 (step S109). Thereafter, the position / posture search unit 122 changes the position / posture of the robot hand 102 to the intermediate position / posture P1, and the extraction position / posture generation unit 123 moves the robot hand 102 in the Z direction again (step S105). Then, the target position arrival determination unit 124 determines again whether or not the robot hand 102 has reached the target position (step S106).

  Thereafter, until the target position arrival determination unit 124 determines that the target position has been reached, the position / posture search unit 122 searches for the intermediate position / posture, and the searched positions / postures are determined as P2, P3, P4,. -2, Pk-1 is stored (repetition of steps S105 to S109). Then, the drawing position / posture generation unit 123 repeats the movement of the robot hand 102 in the Z direction.

  Thereafter, when the target position arrival determination unit 124 determines that the robot hand 102 has reached the target position (YES direction in step S106), the position / posture of the robot hand 102 at that time is set as the extraction completion position / posture Pk. Store (step S110). Then, the work route generation unit 126 connects the pulling movement routes that are the routes connecting the positions and orientations of the robot hand 102 stored in the position and orientation search unit 122 and the target position arrival determination unit 124, that is, a route that connects the pulling movement routes in reverse order in time series, that is, Pk → A path along which the robot hand 102 moves, such as Pk-1 → Pk-2 →... → P2 → P1 → P0, is stored as an assembly work path (step S111). Thereafter, the work route generation unit 126 teaches the assembly work route to the operation control unit 121 and ends the teaching process of the route teaching system 127.

  Therefore, the path teaching system 127 causes the robot hand 102 to grip the assembly work 140 in a state where the assembly to the assembly work 150 is completed, and the robot hand 102 does not have excessive force acting on the assembly work 140. The robot hand 102 is caused to perform the extraction operation of the assembly work 140, and the extraction movement path of the robot hand 102 is acquired during the extraction operation. Then, the route teaching system 127 generates a route that follows the acquired drawing movement route in time series reverse order as an assembly work route, and teaches the generated assembly work route to the operation control unit 121.

  In order to cause the robot 100 to perform the assembling work of the assembling work 140, a method of causing the robot 100 to operate on the acquired assembling work path (teaching playback) may be employed. Alternatively, an assembling operation by force control such as compliance control may be employed based on the acquired assembling work path.

  According to the robot teaching apparatus of the first embodiment as described above, the path teaching system 127 acquires the assembly work path from the pulling movement path searched during the pulling operation by the robot hand 102. Then, the route teaching system 127 teaches the acquired assembly work route to the operation control unit 121. With this configuration, the robot hand 102 does not take a posture in which the assembling work fails during the pulling operation, and the completion of the assembling work is determined based on the reaction force of the assembling work 140 in the pulling direction. do not do. As a result, the operator's initial setting work regarding the operable range of the robot 100 and the allowable output range of the force sensor 110 can be omitted, and the burden of teaching work by the worker can be reduced.

  In addition to this, it is possible to simplify the creation of the robot program and speed up the start-up of the production line, and it is not necessary to adapt the force sensor 110 to the robot 100. The workability of the work can be further improved.

  If the operator sets the drawing direction and drawing completion position (target position) of the assembly work 140 and moves the robot hand 102 to the vicinity of the assembly position of the assembly work 140, the route teaching system 127 An assembly work path is automatically generated based on the output of the force sensor 110. With this configuration, it is possible to obtain an assembly work path for the robot hand 102 in which unnecessary force is not applied to the assembly work 140 as compared with the conventional visual teaching by the operator.

  Furthermore, when force control is used during the assembly work of the robot 100, a space with the obtained work path as the central axis is set as an operable range of the robot 100, so An operable range can be set.

Here, in the conventional apparatus as shown in Patent Document 2, the adjustment of the posture and the posture change during the assembling operation are not taken into consideration. For this reason, there has been a problem that the conventional device as shown in Patent Document 2 cannot be applied to posture adjustment or assembly work involving posture change during assembly.
In contrast, according to the robot teaching apparatus of the first embodiment as described above, the path teaching system 127 indicates that the absolute value of the output of the force sensor 110 has increased during the extraction operation of the robot hand 102. If detected, the intermediate position / posture of the robot hand 102 is searched and stored, and the drawing operation of the robot hand 102 is continued at the stored intermediate position / posture. With this configuration, the route teaching system 127 searches for the optimum position and orientation after the posture change even when the robot hand 102 is pulled out with the posture change. For this reason, even in the case of assembly work that involves posture adjustment or posture change during assembly, the position and posture after the change can be automatically detected and taught to the operation control unit 121. The teaching work about the intermediate position and posture (via point) by the can be made unnecessary.

  In addition to this, since the route teaching system 127 stores only the position and orientation necessary for the posture change, compared with the method of defining the operation route by the position and orientation of the robot hand 102 per unit time, Necessary storage area can be reduced. When the posture change (re-search process) is not necessary during work such as when the insertion direction of the assembly workpiece 140 to the workpiece 150 can be assembled straight, the position and orientation search is performed for the first time (P0). ), The generation of the work route is completed in a short time, and the necessary storage area is suppressed.

  Note that the extraction start position / posture and intermediate position / posture search method according to the first embodiment is an example of an optimum position / posture search method. For the extraction start position / posture and intermediate position / posture search method, the force sensor 110 may be used. However, the present invention is not limited to the search method according to the first embodiment.

Embodiment 2. FIG.
In the first embodiment, the force sensor 110 is attached to the wrist (tip) of the robot arm 101 of the robot 100. On the other hand, in the second embodiment, the force sensor 210 is attached to the bottom of the assembly work jig 200 on which the assembly work 150 is placed.

  FIG. 7 is a cross-sectional view showing an assembly work jig 200 and a force sensor 210 according to Embodiment 2 of the present invention. In FIG. 7, in the second embodiment, the path teaching system 127 operates in the same manner as in the first embodiment if the rattling by the assembled work jig 200 is small, and the drawing movement path and the assembling work path. Can be obtained. That is, the route teaching system 127 can search for the drawing movement route of the robot hand 102 by obtaining the initial value of the output of the force sensor 210 in the drawing operation of the robot hand 102 as a reference value. Thereby, the adaptation operation | work to the robot hand 102 of the force sensor 210 is unnecessary.

Here, as in the first embodiment, when the force sensor 110 is attached to the robot 100 side, the sensor cable of the force sensor 110 is rubbed or moved to the movable part of the robot 100 while the robot 100 is in operation. Interference and handling of the sensor cable, such as a sensor cable being pinched, may be a problem.
In contrast, according to the robot teaching apparatus of the second embodiment as described above, since the force sensor 210 is attached to the assembly work jig 200 side, the sensor cable is separated from the robot hand 102. By doing so, the problem of sensor cable interference and handling due to operation of the robot 100 can be solved.

  Further, the force sensor 210 can be easily removed or replaced as compared with the case where the force sensor 110 is attached to the wrist of the robot arm 101. Furthermore, it is possible to reduce the possibility that the force sensor 210 is damaged by an unexpected operation such as a collision of the robot 100.

  In the first embodiment, the force sensor 110 is attached to the wrist of the robot arm 101, and in the second embodiment, the force sensor 110 is attached to the bottom of the work jig 200 to be assembled. However, the force sensor 110 may be attached to both the wrist portion of the robot arm 101 and the work jig 200 to be assembled.

Embodiment 3 FIG.
In the third embodiment, the force sensor output determination unit 125 monitors the change in the output of the force sensor 110 in the Z direction while causing the robot hand 102 to perform the pulling operation. It is possible to detect whether or not the absolute value of the output in the Z direction has changed in the decreasing direction. When the force sensor output determination unit 125 detects that the absolute value of the output of the force sensor 110 in the Z direction has changed in the decreasing direction, a part or the whole of the assembly work 140 is inserted into the inserted portion 150a. It is determined that it has moved through the inner wall (where the outer surfaces of the workpiece are in contact with each other) and moved to the tapered portion 150b, and the center position searching portion 128 searches for the center position on the opening surface of the tapered portion 150b.

  FIG. 8 is a block diagram showing a robot control apparatus according to Embodiment 3 of the present invention. In FIG. 8, the force sensor output determination unit 125 according to the third embodiment acquires an output in the Z direction of the force sensor 110 during the pulling operation of the robot hand 102, and stores it as a friction handling level. Further, the force sensor output determination unit 125 determines whether or not the absolute value of the output of the force sensor 110 in the Z direction is smaller than the friction corresponding level, that is, whether or not the friction corresponding level has changed in the decreasing direction. To monitor.

  The route teaching system 127 according to the third embodiment further includes a center position search unit 128. When the force sensor output determination unit 125 detects that the absolute value of the output of the force sensor 110 in the Z direction has changed from the friction-corresponding level to the decreasing direction, the center position search unit 128 determines whether the force sensor output determination unit 125 in the inserted portion 150a. An insertion center position (optimum insertion position) that is the center position of the orthogonal surface (opening surface) with respect to the drawing direction is searched, and information on the insertion center position is stored.

  The insertion center position is the same in the Z-direction position and posture (moment about the axis in the translation direction) of the robot hand 102, and the assembly work is obtained when the robot hand 102 is moved along the X-axis and the Y-axis. This is the position of the robot hand 102 that has the longest moving distance until 140 and the work to be assembled 150 come into contact with each other.

  FIG. 9 is a cross-sectional view showing an example of the assembled state of the assembled work 140 and the assembled work 150 according to Embodiment 3 of the present invention. In FIG. 9, a tapered portion (notch) 150 b for facilitating assembly with the assembly workpiece 140 is provided at the opening peripheral portion of the inserted portion 150 a in the assembly workpiece 150 according to the third embodiment. Yes. Here, in the third embodiment, the outer surface of the assembly work 140 is assembled to the inner wall of the inserted portion 150a of the assembly work 150 in a close contact state (a tight fit). Other configurations are the same as those in the first and second embodiments.

  Next, the insertion center position searching process by the center position searching unit 128 will be described. When the extraction position / posture generation unit 123 continues the extraction operation of the robot hand 102 and the tip of the assembly work 140 (the lower end in FIG. 8) reaches the tapered portion 150b of the insertion portion 150a, the assembly work 140 and the assembly work are assembled. Friction due to contact with the workpiece 150 is eliminated, and the output of the force sensor 110 in the Z direction is about the weight of the assembled workpiece 140. That is, as shown in FIG. 10, the absolute value of the output in the Z direction of the force sensor 110 is reduced below the friction corresponding level.

  Then, the force sensor output determination unit 125 indicates that the absolute value of the output in the Z direction of the force sensor 110 has changed from the friction-corresponding level to the decreasing direction (the reaction force in the pulling direction generated in the entire assembled workpiece 140 is reduced). When the change in the decreasing direction: falling) is detected, and thereafter the change in the output direction of the force sensor 110 in the decreasing direction disappears, the center position search unit 128 detects the insertion center position. The search process is started. Accordingly, when the force sensor output determination unit 125 determines that the reaction force in the pulling direction generated in the assembly work 140 changes in the decreasing direction and the force due to friction disappears, the center position search unit 128 determines that the insertion center position The search process is started.

  First, the center position search unit 128 moves the robot hand 102 in the positive direction of the X axis until it detects contact between the outer surface of the assembled workpiece 140 and the inner wall of the inserted portion 150a via the force sensor 110. Let When the center position searching unit 128 detects contact between the outer surface of the assembly work 140 and the inner wall of the inserted portion 150a, the center position searching unit 128 stops the movement of the robot hand 102, and the position of the robot hand 102 at this time is determined as the position PX +. Remember as.

  Subsequently, the center position search unit 128 moves the robot hand 102 in the negative direction of the X axis until it detects contact between the outer surface of the assembly workpiece 140 and the inner wall of the inserted portion 150a via the force sensor 110. Move. When the center position search unit 128 detects contact between the outer surface of the assembly work 140 and the inner wall of the inserted portion 150a, the center position search unit 128 stops the movement of the robot hand 102, and the position of the robot hand 102 at this time is determined as the position PX. Store as-. Thereafter, the center position search unit 128 moves the robot hand 102 to an intermediate point between the position PX + and the position PX−.

  Similarly to the operation on the X-axis, the center position search unit 128 increases the Y-axis until it detects contact between the outer surface of the assembly work 140 and the inner wall of the inserted portion 150a via the force sensor 110. The robot hand 102 is moved in the respective directions of the negative side and the negative side. Then, when the center position search unit 128 detects contact between the outer surface of the assembly work 140 and the inner wall of the inserted portion 150a, the center position search unit 128 stops the movement of the robot hand 102, and determines the position of the robot hand 102 at that time. Store as position PY + and position PY-.

  Finally, the center position search unit 128 stores an intermediate point between the position PX + and the position PX− and an intermediate point between the position PY + and the position PY− as an insertion center position. Thereby, the search process of the insertion center position by the center position search unit 128 ends.

  After the insertion center position searching process by the center position searching section 128, the force sensor output determining section 125 is forced until the target position arrival determining section 124 determines that the target position has been reached, as in the first embodiment. While confirming that the absolute value of the output from the sense sensor 110 is sufficiently small, the extraction position / posture generation unit 123 causes the robot hand 102 to repeatedly perform the extraction operation. At this time, when the force sensor output determination unit 125 determines that the absolute value of the output of the force sensor 110 is large, it is determined that the assembly work 140 has not been pulled out to the taper portion 150b, and the position and orientation search unit 122 executes the insertion center position search process again.

  When the target position arrival determination unit 124 determines that the target position has been reached, the work path generation unit 126 stores each position and orientation of the robot hand 102 stored in the position and orientation search unit 122 and the target position arrival determination unit 124. To obtain the pulling movement route. Subsequently, the work route generation unit 126 adjusts (corrects) the position in the extraction movement route based on the insertion center position stored by the center position search unit 128. Specifically, the work route generation unit 126 includes the translation amount of the robot hand 102 on the XY plane to the insertion center position stored by the center position search unit 128 in a part stored by the position / posture search unit 122 or Add and adjust all positions and orientations.

  Next, as shown in FIG. 11, insertion by the center position search unit 128 when the assembled work 140 is assembled to the inserted part 150 a of the assembled work 150 in a loosely fitted state (a loosely fitted state). The center position search process will be described. Here, as shown in FIG. 10, the force sensor output determination unit 125 according to the third embodiment includes a Z axis direction of the force sensor 110 in a state where the robot hand 102 is holding the assembly work 140 in the air. (The level of the signal from the force sensor 110) is preset as a weight-corresponding level. The weight corresponding level is an output in the Z-axis direction of the force sensor 110 corresponding to the weight of the assembled work 140.

  The force sensor output determination unit 125 monitors whether the absolute value of the output of the force sensor 110 in the Z-axis direction is equal to the weight-corresponding level when the robot hand 102 is performing the pulling-out operation. When the force sensor output determination unit 125 detects that the output of the force sensor 110 in the Z-axis direction is equivalent to the weight-corresponding level, the center position search unit 128 executes the insertion center position search process. The search process in this case is the same as the search process in the case shown in FIG.

  According to the robot teaching apparatus of the third embodiment as described above, when the robot hand 102 is performing the extraction operation, the path teaching system 127 has a reaction force in the extraction direction generated in the assembly work 140. When it is determined that the frictional force has disappeared by changing in the decreasing direction, the insertion center position is searched and stored. Then, the route teaching system 127 adjusts the drawing movement route based on the insertion center position. With this configuration, when the assembly work 140 and the work to be assembled 150 are assembled by the robot 100, the assembly work path based on the adjusted pulling movement path is used, and the inserted portion of the work to be assembled 150 is inserted. The assembly work 140 is moved to the center (taper center) of the opening surface at 150a to start the assembly operation. As a result, the assembly work 140 is attracted to the tapered portion 150b, and the retraction of the assembly work 140 and the work to be assembled 150 is strengthened, and the success rate of the assembly work can be improved.

  Further, when the path teaching system 127 detects that the output of the force sensor 110 in the pulling direction is equivalent to the weight-corresponding level, the robot 100 detects the center (parts) of the inserted portion 150a of the workpiece 150 to be assembled. Assembly is performed by moving the assembly workpiece 140 to the center of tolerance. With this configuration, even when the fitting between the workpieces is loose, the assembled workpiece 140 and the assembled workpiece 150 are drawn more strongly on the opening surface of the inserted portion 150a, and the work success rate can be improved.

  In the search process of the example shown in FIG. 9 in the third embodiment, the absolute value of the output in the Z direction of the force sensor 110 has changed from the friction corresponding level to the decreasing direction, and thereafter the force sensor 110 The starting condition was that the change in the output direction was constant. However, as in the search process of the example shown in FIG. 11, the start condition may be that the reaction force in the pulling direction generated in the assembled work 140 is equal to the weight-corresponding level.

Embodiment 4 FIG.
In the first to third embodiments, the operator performs initial settings relating to the drawing direction of the assembly workpiece 140 and the target position of the extraction operation, and the initial operation of moving the robot hand 102 to the assembly completion position (teaching start position). Was supposed to do. On the other hand, in the fourth embodiment, the off-line programming device 300 automatically provides the route teaching system 127 with initial setting information including the drawing direction and the drawing start position of the assembly work 140 by the robot hand 102.

  FIG. 12 is a block diagram showing a robot control apparatus according to Embodiment 4 of the present invention. In FIG. 12, an offline programming device 300 is connected to the control device main body 120 of the fourth embodiment. The off-line programming apparatus 300 stores CAD data as three-dimensional shape information relating to the three-dimensional shapes of the assembly work 140, the work to be assembled 150, the robot hand 102, and the installation environment of the robot 100 in advance. Yes.

  Further, the offline programming apparatus 300 uses the CAD for initial setting information including the drawing direction / assembly direction of the assembly work 140, the extraction start position of the robot hand 102, and the target position during the extraction operation of the robot hand 102. Performs arithmetic processing based on data. Further, the off-line programming apparatus 300 gives initial setting information, which is a calculation processing result based on CAD data, to the route teaching system 127 (position and orientation search unit 122). The route teaching system 127 according to the fourth embodiment uses the initial setting information given by the off-line programming device 300 to search for the assembly work route of the robot hand 102. Other configurations are the same as those in the first to third embodiments.

  Next, the arithmetic processing based on CAD data by the offline programming device 300 will be described more specifically. First, in the first to third embodiments, the coordinate system as illustrated in FIG. 2 is described in which the drawing direction of the assembly work 140 is the Z axis. In the fourth embodiment, the world coordinate system (Xs, Ys, Zs) is used. ), The workpiece coordinate system (Xw, Yw, Zw), and the robot coordinate system (Xr, Yr, Zr) are defined and described as shown in FIG. In FIG. 13, the rotation around each axis is omitted.

  The world coordinate system in FIG. 13 is a coordinate system associated (fixed) with the work space in which the robot 100 is provided. The workpiece coordinate system is a coordinate system associated with the posture of the assembled workpiece 140. Further, the robot coordinate system is a coordinate system associated with the posture of the robot hand 102. In these coordinate systems, if the posture of the assembly work 140 is changed, the relationship between the world coordinate system and the work coordinate system changes, and if the position and posture of the robot hand 102 changes, the world coordinate system and the robot coordinate system are changed. The relationship changes.

  The world coordinate system can also be handled as a coordinate system associated with the posture of the work to be assembled 150 or the work jig 200 to be assembled. For simplicity of explanation, when the assembly work 140 is gripped (held) by the robot hand 102, the relationship between the work coordinate system and the robot coordinate system is that the unit vector of the coordinate axes is the same and the origin is Be different. Further, an example in which the Z direction is the drawing direction / assembly direction will be described below.

  Here, the assembly method of the assembly work 140 is roughly classified into two types, that is, a first assembly method based on the workpiece coordinate system and a second assembly method based on the world coordinate system. Therefore, the offline programming apparatus 300 performs the definition suitable for each assembling method of the assembling work 140, so that the assembling direction of the assembling work 140 is not related to the posture of the assembling work 140. Whether it is the Zw direction or the Zs direction of the world coordinate system is determined by analyzing the assembly work from the CAD data.

  The first assembling method is a method in which the assembling direction of the assembling work 140 is the Zw direction of the work coordinate system, and the assembling progress surface of the assembling work 140 is always constant. Specifically, a simple assembling operation for assembling so as to draw a straight line in the world coordinate system without changing the posture of the assembling work 140, or as the moving direction of the assembling work 140 changes, the traveling direction of the assembling work 140 changes. It is an assembly work that changes based on the world coordinate system.

  Generally, in order to accurately define the drawing direction for the first assembling method, it is necessary to cause the drawing position / posture generation unit 123 to recognize the workpiece coordinate system by using an external sensor or the like. On the other hand, when the path teaching system 127 causes the robot hand 102 to perform the pulling-out operation, the assembly work 140 and the robot hand 102 are facing each other, so the Zr direction of the robot coordinate system is set to the assembly work 140. (The robot coordinate system can be normally acquired from the motion control unit 121 or the like). That is, it is not necessary for the drawing position / posture generation unit 123 to recognize the workpiece coordinate system.

  Then, the off-line programming apparatus 300 designates the target position with the coordinate value of Zr in the robot coordinate system. For example, the length L of the assembly work 140 and an appropriate offset amount l are set to Zr in the robot coordinate system at the work gripping position P0-1 as the drawing start position (position before the drawing start position / posture P0 is searched). A value added to the direction is designated as the target position. That is, the off-line programming apparatus 300 sets the target position based on the drawing amount of the assembled work 140 (height dimension of the assembled work 140 + offset amount l).

  Next, in the second assembling method, the assembling direction of the assembling work 140 is the Zs direction of the world coordinate system, and the assembling work 140 with respect to the assembling work 150 and the assembling work jig 200 is used. This is a method of changing the posture of the assembly work 140, although the assembly direction is constant. Regarding the second assembling method, the off-line programming apparatus 300 designates the target position by the coordinate value of Zs in the world coordinate system. For example, a value obtained by adding the length L of the assembled workpiece 140 and an appropriate offset amount l to the workpiece gripping position P0-1 in the Zs direction of the world coordinate system is designated as the target position.

  According to the robot teaching apparatus of the fourth embodiment as described above, the initial setting information such as moving the robot hand 102 to the pulling direction, target position, and workpiece gripping position of the assembly work 140 is automatically generated by the offline programming apparatus 300. Is given to the route teaching system 127. With this configuration, the burden on the worker can be further reduced, and the teaching work efficiency of the worker can be further improved.

Here, in general, based on the three-dimensional shape and normal direction of the assembly work, the work to be assembled, the robot hand, and the jig, the grip position of the assembly work in the robot hand and the assembly in the robot hand There is known a method of generating an approach direction until an attached workpiece is gripped, an assembly position of an assembly workpiece, an assembly route, and the like on an off-line (simulation). However, with such a method, it is difficult to realize work with high required accuracy such as assembly work in the position and orientation generated off-line due to the difference between the real environment and the offline environment, and adjustment in the real environment is necessary. Met.
On the other hand, in the robot teaching apparatus according to the fourth embodiment, the position and orientation at which the robot hand 102 first grips the assembly workpiece 140 during the pulling out operation is combined with the robot hand 102 by the position and orientation search unit 122. The position and orientation are adjusted so that the attached workpiece 140 is almost directly facing, and stored as a drawing start position and orientation P0. Accordingly, the workpiece gripping position P0-1 given in advance is sufficient if the robot hand 102 can grip the assembled workpiece 140 even if it is incomplete, and there is almost no shift in the gripping position due to the difference between the actual environment and the offline environment. It doesn't matter.

Embodiment 5 FIG.
In the first to fourth embodiments so far, the pulling direction of the assembly work 140 is always constant regardless of the difference in the coordinate system. On the other hand, in the fifth embodiment, the pulling direction of the assembly work 140 is changed during the pulling operation of the robot hand 102. In other words, the direction of the assembly work 140 is changed in the drawing direction / assembly direction.

  In the fifth embodiment, the drawing direction of the assembly work 140 at the start of the drawing operation of the robot hand 102 (the drawing direction before the change) is the first drawing direction, and the drawing direction of the assembly work 140 after the change is the second drawing direction. This will be described as a direction. This first pulling direction corresponds to the assembling direction of the subsequent process among the assembling processes of the assembling work 140 having two stages. On the other hand, the second pulling direction corresponds to the assembling direction of the previous stroke among the assembling strokes of the assembling work 140 composed of two stages. Further, regarding the pulling operation of the robot hand 102, the pulling operation in the first pulling direction is referred to as a first pulling operation, and the pulling operation in the second pulling direction is described as a second pulling operation.

  As shown in FIG. 15, the force sensor output determination unit 125 of the fifth embodiment, when the absolute value of the output in the first extraction direction (Z direction) among the outputs of the force sensor 110 changes in the increasing direction ( It is determined that the robot hand 102 has reached the position where the pulling direction is changed when the amount is sufficiently larger than the amount generated by the friction between the assembled workpiece 140 and the workpiece 150.

  Here, the reaction force of the assembly workpiece 140 due to friction depends on the drawing movement speed of the robot hand 102. Therefore, if the pulling movement speed of the robot hand 102 is constant, the reaction force of the assembly work 140 is also substantially constant. On the other hand, the reaction force (pressing force) generated in the assembly work 140 when the direction is changed is the movement distance of the robot hand 102 in the first pulling direction after the assembly work 140 hits the inner wall of the inserted portion 150a. Proportional.

  When the assembled work 140 is pressed against the inner wall of the inserted portion 150a, the rate of increase and the amount of increase in the reaction force of the assembled work 140 due to the pressing are the reaction force due to friction with the inner wall of the inserted portion 150a. It is larger than the rate of increase and amount of increase. By using the difference between the increase rate and the increase amount of the reaction force, the force sensor output determination unit 125 determines that the robot hand 102 has reached the position where the extraction direction is changed during the extraction operation of the robot hand 102. judge.

  For example, after pulling out a certain amount (for example, after performing the pulling operation once or twice), the force sensor output determination unit 125 detects the rising of the force in the first pulling direction or the absolute amount of the reaction force is By detecting whether or not the predetermined amount has been reached, it is possible to determine that the robot hand 102 has reached a position where the drawing direction of the assembly work 140 is changed. In general work assembly work, the reaction force due to friction is 1 N or less, and the reaction force due to pressing is 5 N or more. From this, it is possible to distinguish and detect the reaction force caused by friction and the reaction force caused by pressing.

  Next, after the force sensor output determination unit 125 determines that the robot hand 102 has reached the pulling direction change position, the pulling position / posture generation unit 123 sets the pulling direction of the assembly workpiece 140 to the current position. The second drawing direction is changed to a direction different from the one drawing direction.

  The drawing direction after this change, that is, the second drawing direction may be given in advance by the operator in the world coordinate system or the work coordinate system, or automatically by the arithmetic processing based on the CAD data of the offline programming device 300 in the fourth embodiment. It may be set. When the pull-out direction is changed, the position / posture search unit 122 is a position where the absolute value of the output of the force sensor 110 other than the second pull-out direction is minimized around the position / posture in which the pull-out direction is to be changed. The posture is searched, and the searched position / posture is stored as a direction change position / posture.

  Therefore, the position and orientation when the assembly work 140 is pressed against the inner wall of the inserted portion 150a in the first extraction direction in the first extraction operation of the robot hand 102 is excluded from the extraction movement route and the assembly operation route. Other configurations are the same as the configurations of the first to fourth embodiments.

  Next, the operation will be described. Here, the individual operations of the functional blocks 122 to 126 and 128 in the route teaching system 127 will be described collectively as the operation of the route teaching system 127. FIG. 14 is a flowchart showing the teaching process of the route teaching system 127 according to the fifth embodiment of the present invention.

  The operations in steps S201 and S206 shown in FIG. 14 are the same as the series of operations in steps S101 to S104 shown in FIG. 4 in the first embodiment. Further, the operations in steps S204 and S210 shown in FIG. 14 are the same as the series of operations in steps S108 and S109 shown in FIG. 4 in the first embodiment.

  In FIG. 14, the route teaching system 127 searches for the drawing start position / posture P0 and stores the drawing start position / posture P0 (step S201). Then, the route teaching system 127 moves the robot hand 102 in the first pulling direction (step S202). While the robot hand 102 is moving, the route teaching system 127 checks whether or not the absolute value of the output of the force sensor 110 in the direction other than the first pulling direction has increased (step S203).

  At this time, when the path teaching system 127 confirms that the absolute value of the output of the force sensor 110 in the direction other than the first extraction direction has increased (YES direction in step S203), the path teaching system 127 is the intermediate in the first extraction operation. The first intermediate position / posture P1, which is the position / posture, is searched, and the first intermediate position / posture P1 is stored (step S204). Then, the route teaching system 127 again moves the robot hand 102 in the first pulling direction (step S202).

  In addition, when the path teaching system 127 confirms that the absolute value of the output of the force sensor 110 in the direction other than the first pulling direction has not increased (NO direction in step S203), the path teaching system 127 moves to the first pulling direction. It is confirmed whether or not the absolute value of the output of the force sensor 110 has increased (step S205). At this time, if the path teaching system 127 confirms that the absolute value of the output of the force sensor 110 in the first pulling direction has not increased, the robot hand 102 continues to move in the first pulling direction. (Step S202).

  Further, when the path teaching system 127 confirms that the absolute value of the output of the force sensor 110 in the first pulling direction has increased (YES direction in step S205), it searches for the direction change position / posture Pn, The direction change position / posture Pn is stored (step S206). Here, when searching for the direction change position / posture Pn, the path teaching system 127 includes fifth and sixth translation axes orthogonal to the fourth translation axis along the second pull-out direction and orthogonal to each other (both shown in the figure). (Not shown), the robot hand 102 is caused to execute a translational motion along each of the four translational axes, a fourth translational axis, a fifth translational axis, and a sixth translational axis.

  Then, the route teaching system 127 changes the position / posture of the robot hand 102 to the direction change position / posture Pn, moves the robot hand 102 in the second pulling direction (step S207), and has the robot hand 102 reached the target position? It is confirmed whether or not (step S208).

  At this time, when the route teaching system 127 confirms that the robot hand 102 has not reached the target position (NO direction in step S208), the output of the force sensor 110 in a direction other than the second pulling direction is output. It is confirmed whether or not the absolute value has increased (step S209). At this time, when the path teaching system 127 confirms that the absolute value of the output of the force sensor 110 in the direction other than the second pulling direction has not increased (NO direction in step S209), the second instruction is again made. The robot hand 102 is moved in the drawing direction (step S207).

  Further, when the path teaching system 127 confirms that the absolute value of the output of the force sensor 110 in the direction other than the second pulling direction has increased (YES direction in step S209), the intermediate position / posture in the first pulling operation is determined. The second intermediate position / posture PN1 is searched, and the second intermediate position / posture PN1 is stored (step S210). Then, the route teaching system 127 again moves the robot hand 102 in the second drawing direction (step S207).

  Furthermore, when it is confirmed that the robot hand 102 has reached the target position (YES direction in step S208), the path teaching system 127 stores the position and orientation of the robot hand 102 at that time as the drawing-out completed position and orientation Pk. (Step S211). Then, the path teaching system 127 is a path that connects the drawing movement paths, which are paths that connect the stored positions and orientations of the robot hand 102, in a time series reverse order, that is, Pk → Pk−1 → Pk-2 →... Pn2 → Pn1. The path along which the robot hand 102 moves, such as → Pn →... → P2 → P1 → P0, is stored as an assembly work path (step S212). Thereafter, the route teaching system 127 teaches the assembly control route to the operation control unit 121 and ends the series of teaching processes.

According to the robot teaching apparatus of the fifth embodiment as described above, the path teaching system 127 changes the extraction direction from the first extraction direction to the second extraction direction during the extraction operation of the robot hand 102. With this configuration, an assembly work route for the work can be automatically generated even in an assembly work involving a change in the assembly direction of the assembly work 140.
For example, the shape of the assembled work 140 is L-shaped, and the assembled work 140 is inserted into the inserted portion 150a from the L-shaped short side, and the tip of the L-shaped short side of the assembled work 140 is inserted. Even if the assembly work is to be fitted in a groove provided at the bottom of the inserted portion 150a, the assembly work path of the work can be automatically generated.

  Further, the path teaching system 127 searches and stores the direction change position / posture when the pulling direction is changed from the first pulling direction to the second pulling direction, and the direction changing position / posture is extracted by the drawing movement path of the robot hand 102. Include in With this configuration, it is possible to obtain an assembly work path of the robot hand 102 that does not apply unnecessary force to the assembly work 140.

  In the fifth embodiment, two types of drawing directions, the first drawing direction and the second drawing direction, are set in advance. However, this drawing direction may be three or more types. When adding the drawing direction in this way, for example, a series of operations in steps S202 to S206 in FIG. 14 may be added to the overall operation in FIG. 14 in association with the drawing direction to be added. Therefore, the assembly work route can be automatically generated even if the assembly process of the assembly work 140 has three or more stages.

  In addition, when any one of Rx, Ry, and Rz as shown in FIG. 2 is the first or second drawing direction, the assembly work 140 can be rotated in those drawing directions. The present invention can also be applied to assembly work of an assembly work that involves screwing operation.

Embodiment 6 FIG.
In the sixth embodiment, in order to handle the output of the force sensor 110 more accurately, the force output adjustment unit 129 outputs the output of the force sensor 110 with the posture in which the assembly work 140 and the robot hand 102 face each other ( Signal level).

  Here, the posture of the force sensor 110, the position and weight of the center of gravity of the robot hand 102, etc. are unknown information. For this reason, it is difficult to calculate the force applied to the assembly work 140 from the absolute output of the force sensor 110. In the prior art, the absolute output of the force sensor at an appropriate time is set as a reference value, and the relative amount of the output of the force sensor from the reference value is used as the output of the force sensor.

  In order to accurately detect the force applied to the assembly workpiece 140 during the extraction operation of the robot hand 102, a force sensor in a state where the assembly workpiece 140 is gripped in the air with the posture of the robot hand 102 during the extraction operation. It is necessary to adjust the output of the force sensor 110 with an offset amount (adjustment value corresponding to opening / closing and adjustment value corresponding to weight) for removing the absolute output 110.

  In the present specification, “correcting the offset amount” refers to adjusting the output of the force sensor 110 with an offset amount that removes (cancels) the absolute output of the force sensor 110 at that time. . That is, the route teaching system 127 according to the sixth embodiment corrects the offset amount, thereby removing the relative amount between the absolute value of the output of the force sensor 110 and the reference value, and the force sensor after the correction. The signal level of output 110 is treated as “0”.

  FIG. 16 is a block diagram showing a robot control apparatus according to Embodiment 6 of the present invention. In FIG. 16, the route teaching system 127 further includes a force sense output adjustment unit 129. The haptic output adjustment unit 129 acquires an offset amount and corrects the offset amount when executing the drawing operation of the robot hand 102. That is, the route teaching system 127 adjusts the output of the force sensor 110 by the offset amount, and monitors the reaction force generated on the assembly workpiece 140 by gripping the robot hand 102. Other configurations are the same as those of the first to fifth embodiments.

  Next, offset amount acquisition / correction processing by the haptic output adjustment unit 129 will be described. First, as shown in FIG. 17, the force output adjustment unit 129 searches for the drawing start position / posture P0 by the position / posture search unit 122, and then the robot hand 102 holds the assembly workpiece 140 at the drawing start position / posture P0. In this case, an offset amount for removing the output of the force sensor 110 is calculated to obtain the offset amount. Then, the force sense output adjustment unit 129 opens the robot hand 102 (opens the robot hand 102 and releases the assembly work 140). In this state, the force output adjustment unit 129 corrects the offset amount when the output of the force sensor 110 is not equal to the reference value (= 0).

  Thereafter, the force output adjustment unit 129 closes the robot hand 102 (holds the assembly work 140), and confirms that the output of the force sensor 110 is equal to the reference value (sufficiently small). Then, the position / posture search unit 122 is again searched for the drawing start position / posture P0, and the drawing start position / posture P0 is overwritten with the newly searched position / posture. The force output adjustment unit 129 then opens / closes the robot hand 102 and sets a more optimal extraction start position / posture P0 until the output of the force sensor 110 becomes constant regardless of whether the robot hand 102 is opened / closed. The position / orientation search unit 122 repeatedly executes the search.

  When the position / posture search unit 122 acquires the drawing start position / posture P0 at which the output of the force sensor 110 is constant regardless of whether the robot hand 102 is opened or closed, the force sense output adjustment unit 129 opens the robot hand 102, The robot hand 102 is moved from the current drawing start position / posture P0 of the robot hand 102 to an appropriate position / posture of the same posture (different positions) in the world coordinate system. The force output adjustment unit 129 causes the robot hand 102 to grip the assembly workpiece 140 in the air, and if the output of the force sensor 110 is not equal to the reference value in this state, the offset amount is set in this state. Correct it.

  Here, in order to cause the robot hand 102 to grip the assembly workpiece 140 in the air, the operator may cause the robot hand 102 to grip the assembly workpiece 140 after moving the robot hand 102 from the assembly completion position. . Alternatively, when the operation control unit 121 defines a gripping / lifting operation of the assembly workpiece 140 in advance, the operation control unit 121 may execute the gripping / lifting operation. Since the assembly operation from the gripping / lifting operation in the robot hand 102 is a series of operations, there is no problem in the continuous operation, and the robot hand 102 is opened and closed near the assembly start position (extraction end position). However, since it is common to take a posture in which the output of the force sensor 110 is constant, problems such as collision do not occur.

  After correcting the offset amount with the robot hand 102 holding the assembly work 140 in the air, the haptic output adjustment unit 129 opens the robot hand 102 to release the assembly work 140. The robot hand 102 is moved to the position of the drawing start position / posture P0. Thereby, the offset amount acquisition / correction processing by the force sense output adjustment unit 129 of the force sense output adjustment unit 129 ends. Thereafter, the route teaching system 127 searches for the drawing operation route and the assembly work route, as in the first to fifth embodiments.

  Therefore, after the offset amount is corrected, the influence of the movement of the center of gravity of the robot hand 102 due to the change in position and orientation and the influence of the weight of the assembly work 140 are removed from the output of the force sensor 110.

  According to the robot teaching apparatus of the sixth embodiment as described above, the path teaching system 127 adjusts the output of the force sensor 110 with the offset amount, and the reaction generated on the assembly work 140 by gripping the robot hand 102. Monitor power. With this configuration, the influence of the weight of the robot hand 102 and the weight of the assembly work 140 can be removed from the output of the force sensor 110, and assembly with higher accuracy (less force applied to the assembly work 140). A work route can be obtained.

  In the sixth embodiment, the offset amount includes both the opening / closing adjustment value and the weight correspondence adjustment value, and the output of the force sensor 110 is adjusted by both the opening / closing adjustment value and the weight correspondence adjustment value. However, the present invention is not limited to this example, and the output of the force sensor 110 may be adjusted by either the opening / closing adjustment value or the weight adjustment value.

Embodiment 7 FIG.
The control device main body 120 in the robot control device according to the seventh embodiment includes the output status of the force sensor 110 and the pulling direction of the assembly work 140 when, for example, searching for the pulling movement route of the robot hand 102. Display information for displaying at least one of the above is generated. Then, the control device main body 120 sends the generated display information to the teaching box 130 and causes the display unit (display device) of the teaching box 130 to display an image (graph) as shown in FIG. Other configurations are the same as those in the first to sixth embodiments.

  According to the robot teaching device of the seventh embodiment as described above, the operation process of the robot hand 102 and the control device main body 120 and any error state can be displayed to the worker, thereby improving the workability. be able to.

  In the image of FIG. 18 of the seventh embodiment, either one of the output state (vertical axis) of the force sensor 110 and the pulling direction (horizontal axis) of the assembly work 140 is omitted, and the other is numerically displayed. May be.

  Moreover, although Embodiment 1-7 demonstrated the vertical articulated robot, this invention is applicable also to a horizontal articulated robot. Further, in the first to seventh embodiments, teaching of a finger member type (clamping type) robot hand has been described. However, the present invention relates to teaching of a vacuum or magnetic force gripping type robot hand (suction gripping type robot hand). Can also be applied.

  In the first to seventh embodiments, the function blocks 122 to 126, 128, and 129 in the route teaching system 127 are incorporated in the control device main body 120. However, hardware independent of the control device main body 120 may be used as the route teaching system 127. For example, the route teaching system 127 may be incorporated in the teaching box 130 as one function thereof.

  Furthermore, functionally independent hardware or software may be used for the functional blocks 121 to 126, 128, and 129 of the route teaching system 127, or hardware that combines some or all of the functional blocks, or Software may be used. Here, when software is used for at least one of the function blocks 122 to 126, 128, and 129 in the route teaching system 127, design of a mechanical device becomes unnecessary, so that system construction is facilitated. Can do.

  DESCRIPTION OF SYMBOLS 100 Robot, 102 Robot hand, 110,210 Force sensor (force detection means), 120 Control apparatus main body, 121 Motion control part, 122 Position / posture search part, 123 Extraction position / posture generation part, 124 Target position arrival determination part, 125 Force sensor output determination unit, 126 Work route generation unit, 127 Route teaching system (route teaching unit), 128 Center position search unit, 129 Force output adjustment unit, 130 Teaching box, 140 Assembly work, 150 Assembly Workpiece, 150a insertion section, 150b taper section, 200 assembly work jig, 300 offline programming device.

Claims (14)

The position and orientation of the robot hand can be detected. The movement path of the robot hand when the assembly work is inserted into the insertion portion provided in the assembly work and the assembly work is assembled to the assembly work. A robot teaching device comprising a path teaching unit that teaches an assembly work path to an operation control unit that controls the operation of the robot hand,
The route teaching unit includes:
Causing the robot hand holding the assembly workpiece assembled to the assembly workpiece to perform a pulling operation of the assembly workpiece in a preset extraction direction;
During the pulling operation, a pulling movement path that minimizes the reaction force generated on the assembly work by gripping the robot hand is provided from a force detection means for detecting the reaction force generated on the assembly work. Search using the signal of
The robot teaching apparatus, wherein the operation control unit is instructed as the assembling work path of the searched time series reverse order of the drawing movement path. When the route teaching unit causes the robot hand to execute the pulling-out operation,
Translational motion along each of the second and third translational axes perpendicular to and perpendicular to the first translational axis along the pulling direction, the first translational axis, the second translational axis, and the third translational axis The robot hand in a state of gripping the assembly work, and
The position and orientation of the robot hand that minimizes the reaction force generated in the assembly work by these translational and rotational motions is searched, and the searched position and orientation is the starting point of the extraction movement path and the assembly work. The robot teaching device according to claim 1, wherein the robot teaching device stores the drawing start position / posture as an end point of the route. The route teaching unit includes:
When detecting that the reaction force generated in the assembly work has increased from the start time of the extraction operation when the robot hand is performing the extraction operation,
The translational motion along each of the second and third translational axes and the rotational motion around the respective axes from the first translational axis to the third translational axis are in the state of gripping the assembly work. Let the robot hand execute,
The position and orientation of the robot hand that minimizes the reaction force generated in the assembly work by these translational motion and rotational motion are searched, and the searched position and orientation are stored as an intermediate position and posture. The robot teaching apparatus according to claim 2, wherein the drawing operation of the robot hand is continued. The route teaching unit includes:
Monitoring whether or not the robot hand has reached a preset target position when the robot hand is performing the pull-out operation;
When it is detected that the robot hand has arrived at the target position, the position and orientation of the robot hand at that time are the end position and orientation of the withdrawal end that is the end point of the withdrawal movement route and the starting point of the assembly work route. The robot teaching device according to any one of claims 1 to 3, wherein the robot teaching device is stored. The route teaching unit includes:
When it is detected via the force detection means that the reaction force in the pulling direction generated in the assembly work is changed in a decreasing direction when the robot hand is performing the pulling operation. Search for the insertion center position of the orthogonal plane with respect to the drawing direction in the inserted portion, and store information on the insertion center position,
5. The robot teaching apparatus according to claim 1, wherein the drawing movement path is adjusted based on the stored information on the insertion center position. 6. The path teaching unit is a signal level of the force sense detecting means for the pulling direction, and a weight corresponding level corresponding to the weight of the assembled work is preset,
The route teaching unit includes:
When the robot hand is performing the pulling operation, it is detected via the force sense detecting means that the level of the signal of the force sense detecting means in the pulling direction is the level corresponding to the weight. In this case, search for the insertion center position of the orthogonal plane with respect to the drawing direction in the inserted portion, and store the information of the insertion center position.
5. The robot teaching apparatus according to claim 1, wherein the drawing movement path is adjusted based on the stored information on the insertion center position. 6. The route teaching unit includes:
When the robot hand is executing the first extraction operation as the extraction operation, the reaction force in the first extraction direction as the extraction direction among the reaction forces generated in the assembly work has changed in an increasing direction. When the fact is detected via the force sense detecting means, the first pulling operation is stopped by the robot hand,
The robot hand is caused to execute a second pulling operation which is a direction different from the first pulling direction and is a pulling operation toward a preset second pulling direction. The robot teaching apparatus according to any one of the above. When the path teaching unit causes the robot hand to execute the second extraction operation,
Translational motion along each of the fifth and sixth translational axes orthogonal to and perpendicular to the fourth translational axis along the second pulling direction, the fourth translational axis, the fifth translational axis, and the sixth Rotational movement around the axis with respect to each of the translation axes is executed by the robot hand holding the assembly work,
The position and orientation of the robot hand that minimizes the reaction force generated in the assembly work by these translational and rotational motions is searched, the searched position and orientation are stored as the direction change position and orientation, and the direction change position and orientation are stored. The robot teaching device according to claim 7, wherein the robot teaching device is included in the drawing movement path. The route teaching unit includes:
The robot hand in the pulling-out posture is repeatedly executed to hold and release the assembled work, and the robot hand in the pulling-out posture grips the assembled work at the starting point of the pulling movement path. Obtaining an opening / closing correspondence adjustment value for removing the signal level of the force sense detecting means in both the state where the grip is released and the state where the grip is released,
9. The reaction force generated in the assembly work is monitored by adjusting a signal level of the force sense detection means with the adjustment value corresponding to the opening / closing. 9. Robot teaching device. The route teaching unit includes:
When the robot hand in the pulling-out posture is gripping the assembly work in the air, obtain a weight-related adjustment value for removing the signal level of the force detection means at that time,
9. The reaction force generated in the assembly work is monitored by adjusting a signal level of the force sense detection means with the weight-related adjustment value. 9. Robot teaching device. Calculation based on the three-dimensional shape information of the off-line programming device that stores in advance three-dimensional shape information on the three-dimensional shapes of the assembly work, the work to be assembled, and the robot hand in the path teaching unit. By the processing, initial setting information including a drawing direction of the assembly work and a drawing start position of the robot hand is given,
The path teaching unit moves the robot hand to the extraction start position based on the initial setting information, and then causes the robot hand to grip the assembly work assembled to the assembly work. The robot teaching apparatus according to any one of claims 1 to 10, wherein the robot hand is caused to perform the extraction operation in the extraction direction. The path teaching unit generates display information for displaying on the display device at least one of the signal of the force sense detecting unit and the pulling direction when generating the movement path of the robot hand. The robot teaching apparatus according to claim 1, wherein the robot teaching apparatus is a robot. The path teaching unit includes the assembly work through the force detection means attached to at least one of the assembly work jig on which the assembly work is placed and the robot hand. The robot teaching device according to claim 1, wherein a reaction force generated in the robot is monitored. An operation control unit for controlling the operation of the robot hand;
14. A robot control device comprising: a route teaching unit of the robot teaching device according to any one of claims 1 to 13.

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