JP2011224696A - Robot teaching replaying device and teaching replaying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow even a teacher having no knowledge about force control to simply teach and replay contacting work of fitting or the like by an intuitive operation with a high successful rate, by preventing excessive force and increase of tact time.SOLUTION: The robot teaching replaying device includes a force control setting means, a force control manual operation means, a force control state display means and a work state preserving means in a teaching pendant. The force control setting means includes an operation mode selecting means for the respective axial directions of the coordinate system, and the force control manual operation means corrects the operation by increasing/decreasing the positional or force command by superposing it on the operation of the operation program, according to the operation mode during replaying the operation program in a test operation. By the superposed correction operation, the robot work is led to success by the decision of an operator by appropriate force controlling. The data of this time are registered again as the corrected operation program data of the robot. The re-registered operation program is the data appropriately induced by the operator, and therefore, serves as the teaching data with a high success probability.

Description

  The present invention relates to an apparatus for teaching and reproducing a contact operation such as fitting using an industrial robot, and a method for teaching and reproducing.

When performing contact work such as fitting with an industrial robot, a technology is widely known in which a force sensor is provided on the end effector or wrist of the robot manipulator, and a force control mechanism is configured using information obtained from the force sensor. Yes. Industrial robots are based on the teaching and reproduction method, but are basically intended for position control. Therefore, it is necessary to construct a new teaching and reproduction mechanism in the case of contact work by force control. Examples of techniques related to teaching and reproduction of contact work are disclosed in Patent Documents 1 to 8.
Japanese Patent No. 3484675 JP 2002-52485 A JP-A-6-262563 JP 2007-136588 A Japanese Patent No. 3304251 JP 2004-167651 A JP-A-9-91026 Japanese Patent No. 3577124

  In general, in teaching work especially with contact, teaching is performed while paying attention to the position information as well as the position information as a state quantity to teach in order not to generate an excessive force on the workpiece and the robot during the reproduction operation. There is a need to. For this reason, it is difficult to generate optimal teaching data in a single teaching operation, and teaching, reproduction, and correction of teaching are repeatedly performed to generate optimal teaching data. Thus, it takes a very long time to create teaching data because trial and error are repeated.

  In addition, when creating teaching data, there is a case where teaching data is created using a simulator in order to create a robot program offline without guiding an actual robot. However, in offline teaching using a simulator, it is difficult to teach fine operations such as contact work. It is convenient if the position information of the workpiece is taught using a simulator and fine teaching such as contact work can be adjusted in a later test operation.

  The present invention has been made in view of the above-described problems, and in a contact method such as a fitting operation, a simple method can be used without generating excessive force on the workpiece and the robot during teaching and replaying operations. Provided is a robot teaching reproduction apparatus for efficiently correcting teaching data for robot operation.

  According to one aspect of the present invention, a robot teaching and reproducing apparatus is provided. The robot teaching / reproducing apparatus includes a controller that controls the movement of the robot, and a teaching pendant connected to the controller for an operator to teach the robot to operate. The controller can add the teaching from the teaching pendant by the operator to the teaching data being reproduced while the robot is performing a reproduction operation based on the teaching data stored in advance in the controller.

  In one embodiment, the controller can store the teaching data including the teaching added via the teaching pendant during the reproduction operation of the robot as new teaching data in the controller.

  In one embodiment, the teaching pendant can generate a single motion consisting of a plurality of robot motions, and can add a single motion to the teaching data being played. One collective motion here refers to a motion in which the motion speed or motion direction of the robot changes.

  In one embodiment, the controller, during the reproduction operation, based on at least one of information obtained from a sensor attached to the robot end effector and information obtained from an internal sensor of the robot, The state value is calculated, and the evaluation value is calculated using the difference between the state value of the robot end effector stored when the teaching data corresponding to the calculated state value is created and the calculated state value, By comparing the evaluation value with a predetermined value, it is possible to determine whether the operation of the robot is performed as taught.

  In one embodiment, the controller, during the reproduction operation, based on at least one of information obtained from a sensor attached to the robot end effector and information obtained from an internal sensor of the robot, A plurality of state values are stored, and a difference between each of the plurality of state values of the robot end effector stored when the teaching data corresponding to the calculated state value is created and each of the plurality of state values calculated is calculated. The second evaluation value is used to calculate, and by comparing the second evaluation value with a predetermined value, it can be determined whether the robot operation has been successful as taught.

  In one embodiment, the calculation of the state value of the end effector of the robot is performed at a predetermined frequency. Preferably, the frequency is relatively high when the operation speed of the robot is high, and is relatively low when the operation speed of the robot is low.

  According to one aspect of the present invention, a robot teaching method is provided. This method includes a step of replaying a robot based on pre-prepared preliminary teaching data, and a further teaching in addition to the preliminary teaching to the robot that is performing the replaying operation when the robot is replaying according to the preliminary teaching data. Providing in a superimposed manner.

  According to one aspect of the present invention, a robot teaching data creation method is provided. This method includes a step of replaying a robot based on preliminary teaching data created in advance, and a robot that is performing a replaying operation of additional teaching data in the preliminary teaching data when the robot is replaying according to the preliminary teaching data. Adding to the preliminary teaching data.

It is a block diagram of the teaching reproduction | regeneration apparatus of the robot in one Embodiment of this invention. It is a flowchart of the teaching reproduction | regeneration method of the robot in one Embodiment of this invention. It is a figure explaining the teaching of the movement operation to a fitting approach point, (a) represents the state of a robot, and (b) represents an operation program. It is a figure explaining the manual operation procedure of force control in a non-contact state, (a) represents the state of a robot, and (b) represents the state of a teaching pendant. It is a figure explaining the teaching procedure of a contact state, (a) represents the state of a robot, (b) represents the state of a teaching pendant. It is a figure explaining the procedure of search operation, (a) represents the state of a robot, (b) represents the state of a teaching pendant. It is a figure explaining the teaching procedure of a fitting state, (a) represents the state of a robot, (b) represents the state of a teaching pendant. It is a figure explaining the procedure of insertion operation, (a) represents the state of a robot, (b) represents the state of a teaching pendant. It is a figure explaining the procedure of clogging elimination operation, (a) represents the state of a robot, (b) represents the state of a teaching pendant. It is a figure explaining the teaching procedure of an insertion completion state, (a) represents the state of a robot, (b) represents the state of a teaching pendant. It is a figure showing the operation | movement program converted from teaching data. 6 is a flowchart illustrating a robot re-teaching method according to an embodiment of the present invention; It is a figure explaining the comparison of the state of the robot at the time of teaching and reproduction | regeneration, (a) represents position information, (b) represents torque information. It is a figure showing information presentation to an operator by a teaching pendant. It is a figure showing the connection of a general robot system and peripheral devices. It is a block diagram of a general industrial robot. It is a block diagram of impedance control. It is a figure which shows the state classification | category of a fitting insertion work, and is a figure which shows (a) contact state (b) fitting state (c) insertion completion state.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a general industrial robot and a system configuration of force control (both known techniques) will be described, and then an embodiment of teaching data creation using a teaching pendant and reproduction of the robot based on the teaching data will be described. Subsequently, correction of teaching data and determination of robot operation error according to the present invention will be described.

General industrial robot and system configuration of force control FIG. 15 is a configuration diagram of a general industrial robot. In FIG. 15, a robot 101 is a manipulator having a plurality of joint axes and links. Each joint shaft has a built-in drive motor with an encoder, and each joint can be driven independently. The robot 101 is connected to a controller 102, and the controller 102 constitutes feedback control (position control system) based on the encoder signal of each joint axis drive motor together with the robot 101 to control the movement of the robot 101. The controller 102 is connected to a teaching pendant 103 that is an interface for a teacher to manually (JOG) operate the robot and to create and edit an operation program. The teaching pendant 103 mainly includes an operation button group 103a and a display screen 103b. The robot 101 includes an end effector 104 provided on the wrist. Various tools can be attached as end effectors depending on the application. In the case of FIGS. 15 and 16, a hand (gripper) for gripping a component is attached.

  FIG. 16 shows a configuration diagram of an industrial robot subjected to force control. The robot 101 includes a six-axis force sensor 105 attached to the wrist, and can measure the forces in the XYZ axial directions and the moments around the respective axes. The controller 102 includes an internal force control means 106, and the force control means 106 constitutes a feedback control system (force control system) based on signals from the force sensor 105 and each axis encoder. The force control unit 106 outputs a torque command or a current command for each drive motor, and the actuator drive amplifier unit 107 supplies power to each drive motor based on the torque (or current) command value. The controller 102 includes an operation program storage unit 108 that stores an operation program created (teached) by the teaching pendant inside the controller. The controller 102 includes operation program execution means 109 that interprets and executes the operation program stored in the operation program storage unit 108 and gives an operation command to the force control unit 106. The end effector 104 can grip the fitting part 110a, and the fitting part 110a is fitted to the fitting part 110b. By placing the robot 101 in the force control state, it is possible to allow the fitting component 110a to be fitted to the fitting component 110b while allowing a position and orientation error.

  As a specific force control method, impedance control is generally used. FIG. 17 shows a control block diagram of general impedance control. In FIG. 17, reference numeral 106 a denotes a position control system that outputs torque (or current command) of each drive motor to the actuator drive amplifier unit 107 based on the position command of each joint axis and the current position (feedback). Fref is a force moment command (force moment target value), and Ffb is a force moment feedback value. θref is a position command (joint coordinate system) sent from the operation program execution unit 109, and δθ is a position correction amount calculated by the impedance control calculation unit 106b. First, the impedance control calculation unit 106b calculates the position correction amount δP in the orthogonal coordinate system based on Fref and Ffb according to the following equation (106c).

δP = (Ms ² + Ds + K) ⁻¹ (Fref−Ffb)
Here, M, D, and K are an inertia matrix, a viscosity coefficient matrix, and a stiffness matrix (spring constant), respectively. Normally, these are set as diagonal matrices, and independent impedance characteristics are set in the respective axial directions. Moreover, s is a Laplace operator and corresponds to the first derivative with respect to time.

The position correction amount δP in the orthogonal coordinate system is decomposed into the position correction amount δθ in the joint coordinate system using the Jacobian matrix J (θ) by the following equation (106d).
δθ = J (θ) ^-1 δP
By giving the position control system 106 a a position command θref ′ obtained by adding δθ to θref, the robot is operated while maintaining the characteristics specified by M, D, and K with respect to external force and moment. For example, the robot operates like a spring against an external force due to K, and at that time, M and D are reduced to operate lightly and smoothly.

Creation of teaching data using a teaching pendant Next, a system configuration for creating teaching data using a teaching pendant and an embodiment of a teaching data creation method will be described. FIG. 1 is a block diagram of a robot teaching and reproducing apparatus according to one embodiment. In FIG. 1, elements (101 to 110) having the same reference numerals as those in FIG.

  The teaching pendant 103 includes a force control setting unit 111, a force control manual operation unit 112, a force control state display unit 113, and a work state storage unit 114. The force control setting unit 111, the force control state display unit 113, and the work state storage unit 114 are displayed on the display screen 103b of the teaching pendant 103. The display screen 103b is of a liquid crystal touch panel type, and the teacher touches the software key displayed on the display screen 103b, whereby each of the force control setting means 111, the force control state display means 113, and the work state storage means 114 is displayed. The means can be operated.

  The force control manual operation means 112 of the teaching pendant 103 includes an operation button group 103a corresponding to each operation. In FIG. 1, the force control manual operation means 112 is realized as the operation button group 103a, but may be replaced with a software key. Further, when the instructor operates the software keys displayed on the operation button group 103a and the display screen 103b of the teaching pendant 103, various screens other than the screen shown in FIG. 1 are displayed on the display screen 103b. You may be able to do that.

The force control setting unit 111 includes a first coordinate system selection unit 111a, a force control start / end unit 111b, and an operation mode selection unit 111c.
First, by touching the first coordinate system selection unit 111a, it is possible to select which coordinate system is used to execute force control. For example, the coordinate system can be switched in order of robot coordinate system → tool coordinate system → user coordinate system → robot coordinate system →.

  An example of the robot coordinate system and the tool coordinate system is shown in FIG. As shown in FIG. 15, the robot coordinate system is generally defined as an orthogonal coordinate system with the base of the robot as the origin. The tool coordinate system is generally defined as an orthogonal coordinate system having an origin at or near the end effector. The user coordinate system is a coordinate system that can be arbitrarily determined by a teacher in addition to the robot coordinate system and the tool coordinate system.

  When the coordinate system is selected and the force control start / end means 111b is touched, the robot 101 at the time of teaching can be operated in the impedance control state. If the force control start / end means 111b is touched in the impedance control state, the impedance control can be ended and the normal position control can be restored.

  The operation mode selection unit 111c touches each of the X, Y, and Z buttons, thereby “position”, “constant force”, “vibration force” for each axis direction of the coordinate system selected by the first coordinate system selection unit 111a. ”Can be selected. Taking the Z button as an example, each time the button is touched, it is switched in the order of “Z: position” → “Z: constant force” → “Z: vibration force” → “Z: position” →. Can be.

  The robot operation in each mode is as follows. When the “Z +” or “Z−” button of the force control manual operation means 112 is pressed while the Z direction is set to “Z: position”, the Z component of the position command Pref (FIG. 17) is changed according to the button operation. The robot can be operated manually by increasing or decreasing the value. That is, the same operation as a normal JOG operation is performed. When the “Z +” or “Z−” button of the force control manual operation means 112 is pressed with the Z direction set to “Z: constant force”, a force command Fref ( The value of the Z component in FIG. 17) increases or decreases, and the robot can be manually operated. When the “Z +” or “Z−” button of the force control manual operation means 112 is pressed with the Z direction set to “Z: vibration force”, the Z component of the force command Fref (FIG. 17) to the force control means 106 Changes along a waveform having a constant amplitude and period (frequency), and the robot can be manually operated. Change amount per hour (speed) (mm / s) when manually manipulating the position command to the robot by button operation, change amount per hour (N / s), amplitude (when manipulating the force command manually) N) and frequency (Hz) are selected by touching each display location of the operation mode selection means 111c, and the values are increased or decreased by pressing the “high” and “low” buttons of the force control manual operation means 112. Can be adjusted. The usage of the “Previous” button and “Next” button of the operation mode selection unit 111c will be described later.

  The force control state display means 113 can display the change in the position and force of the robot 101 in the impedance control state in real time with a figure or a numerical value. For example, as shown in FIG. 1, force command Fref, force feedback (force FB) Ffb, position command Pref, and position feedback (position FB) Pfb are displayed as bar graphs and numerical values. The force control state display unit 113 includes a second coordinate system selection unit 113a and an axis selection unit 113b. By touching the second coordinate system selection unit 113a, changes in position and force can be displayed based on a desired coordinate system in the same manner as the first coordinate system selection unit 111a. Normally, the same coordinate system as that selected by the first coordinate system selection means 111a will be selected. When the axis selection unit 113b is touched, the axes can be switched in order of X axis → Y axis → Z axis → X axis →. Of the axes of the coordinate system designated by the second coordinate system selection means 113a, the position and force information related to the axial direction selected by the axis selection means 113b is displayed by one or both of a graph and a numerical value.

  The teacher uses the force control setting unit 111 and the force control manual operation unit 112 while confirming the position and force state displayed on the force control state display unit 113, so that the component held by the hand can be detected. The contact state, that is, the work state can be changed by an intuitive operation. The teacher determines and selects what work state the part is in, and performs an explicit operation (for example, the teacher touches the “save” button in the work state storage unit 114) at an appropriate time. Thus, the work state storage unit 114 stores the force command Fref, force feedback Ffb, position command Pref, position feedback Pfb, and the like at that time together with the type of work state in the teaching data storage unit 115 in the controller 102 as teaching data. Can be remembered.

  As shown in FIG. 16, in the case of the fitting insertion work in which the fitting part 110a gripped by the end effector 104 is fitted into the hole of the fitting part 110b and inserted to the bottom of the hole, the working state is shown in FIGS. As shown in (c), three states of “contact state”, “fitting state”, and “insertion completion state” are defined, and when the teaching data is stored in the work state storage unit 114, which one of the three states is stored. It can be specified together. Specifically, by setting the “contact”, “fitting”, and “insertion completion” buttons in the work state storage unit 114, it is clearly indicated in which work state the robot is in when the teacher touches each button. Can be specified. These three buttons are alternatives. Further, when the “conversion” button of the work state storage unit 114 is pressed after completion of the teaching of a series of work states, the teaching data conversion unit 116 in the controller 102 is activated, and each work state stored in the teaching data storage unit 115 is related. The position and force data is converted into an operation program and stored in the operation program storage unit 108. Details of the conversion of the teaching data into the operation program will be described later.

  In the above description, the teacher explicitly specifies which work state the teaching data should be stored by touching the button of the working state storage unit 114, but in most cases, "contact" "fitting" Since the teaching work proceeds in the order of “insertion completed”, the work state may be automatically switched in order each time the teacher touches the “save” button. When teaching the contact state, the instructor touches the force control start / end unit 111 in advance to shift to the force control state, and at that time, automatically touches the “contact” button of the work state storage unit 114. It should be in a state.

  When the conversion to the operation program is completed, the robot mode is changed from the teaching mode to the reproduction operation mode as is conventionally done, and the converted operation program is reproduced, so that “contact”, “fitting”, “ The operation of “Insert complete” is reproduced.

  As described above, the robot teaching / reproducing apparatus according to the above-described embodiment has the force control setting unit 111, the force control manual operation unit 112, the force control state display unit 113, and the work state storage unit on the display screen 103b of the teaching pendant 103. 114 is provided, and the instructor is skilled in teaching by force control by performing teaching while appropriately changing the operation mode by the force control setting unit 111 while visually checking the data on the force and position by the force control state display unit 113. Even if it is not, it is possible to teach the fitting and insertion work without operating the force control manual operation means 112 intuitively and applying excessive force to the workpiece and the robot.

  Next, a teaching method in the robot teaching / reproducing apparatus shown in FIG. 1 will be described. FIG. 2 is a flowchart of a robot teaching method and reproducing method according to an embodiment. Hereinafter, according to FIGS. 2 to 11, the teaching of the fitting insertion work will be described in detail. First, as shown in FIG. 3, the tool coordinate system 301 of the end effector (hand) 104 is set by the teaching pendant 103, and the hand 104 gripping the fitting part 110a is approached to the hole of the fitting part 110b (see FIG. 3). After the movement to POOO) of 3 (a), the movement instruction “MOV POOO V = 10” up to the approach point is registered in the operation program as shown in FIG. 3B (S201). In FIG. 3B, the operation program is displayed by switching the display content of the display screen 103b. Here, MOV is a movement command for the robot, and designates the target hand position of the robot in POOO. V = 10 specifies the moving speed to the target position (POOO). In this embodiment, the tool coordinate system 301 is set so that the origin is located at the tip of the fitting part 110a held by the hand as shown in FIG. Although the Y axis of the tool coordinate system is not described, the tool coordinate system is an orthogonal coordinate system, and the Y axis is defined in a direction orthogonal to the paper surface. When setting the tool coordinate system, it is common to make one of the axes coincide with the axis of the fitting part 110a so that the teacher can intuitively operate the robot based on the tool coordinate system. In FIG. 3A, the axis of the fitting part 110a is the Z axis of the tool coordinate system, but this may be the X axis or the Y axis. Further, the position command and position feedback indicate the position of the origin of the tool coordinate system 301.

  Subsequently, as shown in FIG. 4B, the screen display of the teaching pendant 103 is switched, the “tool coordinate system” is selected by the force control setting means 111, and the state is further shifted to the force control (impedance control) state (S202). ). The coordinate system of the force control state display means 113 is set in advance to the “tool coordinate system” and the axis is set to “Z axis”. 4B, the force control setting unit 111 sets the operation mode in the Z-axis direction (part fitting direction) of the tool coordinate system to “Z: position”, and the bar graph of the force control state display unit 113. While confirming the display, the "Z +" button of the force control manual operation means 112 (operation button group 103b) is pressed to move the arm in the Z direction of the tool coordinate system. The state of the robot at this time is shown in FIG. The movement speed at this time is to touch the “mm / s” button next to “Z: position” of the force control setting means 111 and press the “high” and “low” buttons of the force control manual operation means 112. (S203).

  When the fitting part 110a comes into contact with the part to be fitted 110b, the force feedback value of the force control state display means 113 changes from zero as shown in FIG. 5B, so the teacher determines the contact between the parts. be able to. When the teacher determines that the contact is made, the “Z +” button of the force control manual operation means 112 is released. In the “Position” operation mode, the contact state is maintained even if the corresponding component (in this case, the Z component) of the spring constant K for impedance control according to Equation (1) is set to non-zero and the “Z +” button is released. ing. As shown in FIG. 5A, while the contact state is maintained, the “contact” button of the work state storage unit 114 is touched to select “contact state”, and the “save” button is touched to teach the contact state. Is stored in the teaching data storage unit 115. A force feedback value (butting force) and a position feedback value (contact position) are stored as teaching data of the contact state (S204).

  Next, the state is changed from the contact state in FIG. 5A to the fitted state in FIG. 7A by manual operation (probing operation). The search operation will be described with reference to FIG. As shown in FIG. 5A or 6A, it is assumed that the fitting part 110a is displaced in the X direction of the tool coordinate system with respect to the hole of the fitting part 110b. First, the operation mode in the X direction of the force control setting unit 111 is switched to “vibration force”. When switching to "vibration force", buttons of amplitude "N" and frequency "Hz" appear next to it. The amplitude of the vibration force can be adjusted by touching (selecting) the “N” button and pressing the “high” or “low” button of the force control manual operation means 112. Similarly, the frequency of the vibration force can be adjusted by touching (selecting) the “Hz” button and pressing the “high” and “low” buttons. This state is shown in FIG. In FIG. 6B, “10N” on the right side of “X: vibration force” of the operation mode selection unit 111c represents the amplitude of the vibration force, and “10 Hz” represents the frequency. By pressing the “X +” or “X−” button of the force control manual operation means 112 in the state of switching to “vibration force”, while the button is being pressed, the force command value Fref to the force control means 106 is changed. A vibration force is applied to the X component, and the gripping fitting part 110a can be reciprocated in the X-axis direction in a state where the fitting part 110a is in contact with the fitting part 110b. When the “X +” button is pressed, it reciprocates with the X + direction as the initial direction. When the “X-” button is pressed, the robot reciprocates with the X-direction as the initial direction. Further, not only in the X-axis direction but also in the Y-axis direction, the operation mode selection unit 111c of the force control setting unit 111 switches the operation mode to the “vibration force” mode, and the “X−” button and “Y +” or “Y” By simultaneously pressing the “-” button, it can be reciprocated in any direction on the XY plane. Further, by pressing the “high” and “low” buttons while pressing the “X-” button, the amplitude (or frequency) can be increased or decreased while actually reciprocating. Therefore, if you do not know how much amplitude you want to set, set the amplitude to zero (ON), and while pressing the “X-” button, press the “High” button to gradually increase the amplitude. Just make it larger. Since the abutting force in the Z direction (see FIG. 5) is maintained in a reciprocating motion (probing operation), when the center axes of the fitting part 110a and the fitting part 110b coincide, as shown in FIG. On the other hand, the fitting part 110a is in a state of being slightly fitted in the hole of the fitting part 110b.

  Since the force in the Z direction of the tool coordinate system suddenly decreases and the position feedback value increases simultaneously at the moment of transition from the contact state to the mating state (the moment when the mating part 110a fits into the hole) It can be determined whether or not the component 110a is fitted in the hole. When the teacher determines the mating, release the “X-” button to stop the search operation. Since the Z component of the spring constant K for impedance control is non-zero, the fitted state is maintained (S205).

  When the fitting state as shown in FIG. 7A is reached, the “fitting state” is touched by touching the “fitting” button of the work state storage means 114 as shown in FIG. 7B while maintaining the state. And the “save” button is touched to store the teaching data in the fitted state in the teaching data storage unit 115. As teaching data of the fitting state, the position feedback value (fitting position) in the fitting state and the amplitude and frequency at the time of the search operation (FIG. 6) are stored (S206).

  Subsequently, as shown in FIG. 8B, the operation mode in the Z direction is switched to “constant force” by the force control setting means 111. When switching to “constant force”, the Z component of the spring constant K for impedance control is automatically set to zero. In this state, the “Z +” button is pressed again as shown in FIG. When the operation mode is “constant force”, the Z component of the force command Fref to the impedance control (force control means 106) continues to increase while the “Z +” button is pressed. Conversely, the Z component of the force command Fref continues to decrease while the “Z-” button is pressed. The rate of change of the increase / decrease is adjusted by touching (selecting) the “N / s” button next to “Z: constant force” and then pressing the “high” and “low” buttons of the force control manual operation means 112. be able to. Moreover, since the force command value currently applied is displayed on the force control state display means 113 together with the force feedback value, the teacher can always operate the button while visually grasping the force state. When the force command Fref in the Z + direction is gradually increased and Fref exceeds the frictional force between the parts, the fitting part 110a starts moving toward the hole bottom of the part to be fitted 110b (S207). This is shown in FIG. The teacher can release the “Z +” button at this stage. Note that the force feedback value (absolute value) during movement is smaller than the force command value (absolute value). If there is an error in the fitting direction (the smaller the fitting tolerance is, the smaller the allowable error is), a “clogging” may occur in which the fitting part 110a gets caught in the hole of the fitting part 110b during insertion. However, in that case, the operation to eliminate the clogging as described below is performed manually. Whether or not clogging has occurred can be confirmed by the difference between the position command and the position feedback in the bar graph display or numerical display of the force control state display means 113. It can also be confirmed by the teacher visually observing the position of the fitting part 110a or listening to the sound generated by the interference between the fitting part 110a and the hole of the fitting part 110b.

  The clogging eliminating operation will be described with reference to FIG. Assume a case where clogging occurs because the fitting part 110a is tilted around the Y axis of the tool coordinate system as shown in FIG. As shown in FIG. 9B, the teacher first changes the screen from the translation motion axis (XYZ axis) to the rotation motion axis (RxRyRz axis) by touching the “next” button of the operation mode selection means 111c. The operation mode in the Ry axis (rotation around the Y axis) direction of the force control setting unit 111 is switched to “vibration force”. Whether the operation mode selection unit 111c selects the operation mode for each axis direction (XYZ) of the coordinate system selected by the first coordinate system selection unit 111a by touching each button of the “Previous” and “Next” buttons. It is possible to switch whether to select the operation mode for each axis (RxRyRz). As in the search operation (see FIG. 6), the amplitude of the vibration force (moment “Nm” instead of force “N” in the case of rotational operation) and the frequency are adjusted, and “Ry +” of the force control manual operation means 112 is adjusted. Alternatively, the “Ry−” button is pressed to apply moment vibration to the gripped fitting part 110a. Since the force in the Z direction remains maintained, the insertion operation resumes (starts moving again in the Z direction) when clogging (catch) is eliminated by moderate moment vibration. If you do not know how much amplitude vibration should be set to zero, set the amplitude to zero (ONm) and press the “High” button while holding down the “Ry +” button to gradually increase the amplitude. Just make it larger. Also, clogging may be eliminated by applying vibration (translational force) in the X-axis direction in the same manner as the search operation instead of moment vibration. When the movement is stopped after the insertion is completed, the force command value and the force feedback value are balanced. In addition, the force control state display means 113 shows a state where the hole bottom has been reached (insertion completion state) by observing the difference between the position command value (the position in the fitted state) and the position feedback value (the amount of movement from the fitted state). ).

  When the insertion is completed as shown in FIG. 10 (a), the teacher saves the work state while maintaining the insertion completion state (while the force command value is applied in the Z + direction) as shown in FIG. 10 (b). The “insertion completion” button of the means 114 is touched to select the insertion completion state, and the “save” button is touched to store the teaching data in the insertion completion state in the teaching data storage unit 115. As teaching data in the insertion completion state, a force command value (insertion force) and a position feedback value (insertion completion position) in the insertion completion state are stored. Further, the amplitude and frequency set during the clogging operation are also stored (S208).

  When a series of teachings from contact to insertion is completed and the instructor touches the “conversion” button of the work state storage unit 114, the teaching data conversion unit 116 in the controller 102 operates and is stored in the teaching data storage unit 115. The teaching data is converted into the operation program shown in FIG. 11 and stored in the operation program storage unit 108 (S209). FIG. 11 shows a state in which the operation program is displayed as shown in FIG. In the above description, the state buttons “contact”, “fitting”, and “insertion completion” of the work state storage unit 114 are explicitly touched to select a state, and then the “save” button is touched. However, each time the “save” button is touched, the state may automatically change from “contact” to “fitting” and “insertion completion”. Although the “conversion” button is explicitly touched, the teaching data may be automatically converted into an operation program when “save” is pressed in the “insertion completed” state.

  As shown in FIG. 11, the operation program converted based on the teaching data by touching the “convert” button is a force control start command “IMPON” for shifting from the position control state to the force control state. Abutment operation command “TSUKIATE” for shifting to the contact state, a search operation command “SAGURI” for shifting to the mating state by searching for the hole position while maintaining the contact state, and an insertion operation command for shifting from the mating state to the insertion completion state It consists of “INSERT” and a force control end command “IMPOFF” for returning from the force control state to the position control state. In the “TSUKIATE” command, V, Dir, F, and L are specified as parameters. In the “SAGURI” command, F, L, Fv, and Tv are specified as parameters. In the “INSERT” command, F, L, Mv, and Tv are specified as parameters. These parameters are automatically determined based on the values stored in the teaching data storage unit 115 as teaching data in each state. Details will be described later.

Reproduction operation of robot based on teaching data The above is the teaching procedure of the mating insertion work in the teaching mode. Next, a case where the robot is operated according to an operation program created by teaching during the reproduction operation will be described. When switching from the teaching mode to the reproduction operation mode and reproducing the converted operation program (S210), the robot first holds the fitting part 110a by the end effector 104 and moves to the approach point POOO by position control (S211). . Next, a force control start command (IMPON command in FIG. 11) is executed to shift to a force control state (S212).

  After the transition to the force control state, an abutting operation command (TSUKIATE command in FIG. 11) is subsequently executed (S213). In the abutting operation command of FIG. 11, the tool moves in the Z + direction of the tool coordinate system specified by “Dir” at the speed Vap specified by “V”, and when contact is detected, specify “F” in the Z + direction. The applied force command value Fpush is added, and after the contact detection, if it moves by the movement amount Lpush designated by “L”, it is determined that the fitting state is reached, and the process proceeds to the next step. The contact detection is automatically determined by comparing the force feedback value detected during the reproduction operation with a preset threshold value (contact force). In addition, in the force command value Fpush after contact detection, the abutting force of the contact state teaching data in S204 is automatically set at the time of teaching, and it is not necessary for the teacher to input a numerical value. Further, in the determination of the fitting state, the Z direction difference value between the position feedback value (fitting position) of the fitting state teaching data and the position feedback value (contact position) of the contact state teaching data stored in S204 is the movement amount. It is automatically set as the threshold value Lpush, and there is no need for the teacher to input the threshold value numerically. For the speed Vap designated by “V”, a value preset in the controller is used, and is automatically assigned at the time of operation program conversion. It is also possible to change if the moving speed is unsuitable after actually performing the butting operation.

  If the movement amount does not reach the threshold value Lpush within a predetermined time from the execution of the hit operation command, it is determined that the hit operation command has failed, and the search operation command (SAGURI command in FIG. 11) is executed (S214). If the hit operation command is successful, the search operation command is skipped. The search motion command maintains the abutting force Fpush in the Z + direction specified by “F”, and the vibration force of the amplitude Fvib specified by “Fv” and the period Tvib specified by “Tv” is z It is monitored whether the amount of movement in the Z + direction reaches the threshold value Lpush while being applied in the vertical direction of the axis. If the threshold value Lpush is exceeded within a predetermined time, the process is terminated as success, and if it does not reach Lpush, the process is terminated as a failure and the force control is terminated by a force control end command (IMPOFF command in FIG. 11) (S216). The amplitude Fvib and period Tvib of the search operation command are adjusted during the search operation during teaching (see FIG. 6), and the vibration force amplitude and frequency reciprocal stored in the teaching data storage unit 115 in S206 are automatically set. The teacher is not required to input numerical values.

  If the hit operation command or the search operation command is successful, an insert operation command (INSERT command in FIG. 11) is executed (S215). In the insertion operation command, the force command value Fins designated by “F” is added in the Z + direction, and when the movement amount after contact detection becomes Lins designated by “L”, it is determined that the insertion is completed, and the process ends. For the force command value Fins, the Z direction force command value (insertion force) of the teaching data in the insertion completion state stored in the teaching data storage unit 115 in S208 at the time of teaching is automatically set, and the teacher needs to input a numerical value. There is no. As for the insertion amount threshold value Lins, the position feedback value (contact position) of the contact state teaching data stored in the teaching data storage unit 115 in S204 at the time of teaching, and the position of the insertion completion state teaching data stored in S208. The Z-direction difference value with respect to the feedback value (insertion completion position) is automatically set, and there is no need for the teacher to input a numerical value. If it stops in the middle of insertion (before the movement amount reaches Lins), it is judged that clogging has occurred, and the moment vibration of the amplitude Mvib specified by “Mv” and the period Tvib specified by “Tv” is applied. Execute clogging clearing operation. The amplitude Mvib and period Tvib of the clogging elimination operation are adjusted during the clogging elimination operation at the time of teaching (see FIG. 9), and the amplitude of the vibration force stored in the teaching data storage unit 115 in S208 and the reciprocal of the frequency are respectively set. It is automatically set and the teacher does not need to input numerical values.

  When the insertion operation command is completed, a force control end command (IMPOFF command in FIG. 11) is executed, and a transition is made from the force control state to the position control state (S216). Thereafter, the end effector 104 is opened and the fitting part 110a is released to complete the fitting insertion work. As described above, according to the present embodiment, it is possible to easily teach a fitting / inserting operation by an intuitive operation, and teaching data obtained in each state of “contact”, “fitting”, “insertion completion” at the teaching stage is an operation program. Because it is automatically converted to this parameter, the time required for the teacher to input numerical values for the parameter can be saved and the teaching work time can be shortened.

  As described above, the teaching in the force control state using the teaching pendant and the reproduction of the robot have been described, but the teaching relating to the contact work is performed while paying attention to both position and force information as the teaching state quantity. Since this is a complicated operation, the teaching data may not be optimal in one teaching. Therefore, it is convenient that the created teaching data can be easily corrected later. Therefore, the present invention makes it possible to correct teaching data by a simple method as described below, and to efficiently create a robot operation program.

Correction of teaching data In the following description of embodiments of the present invention, it is assumed that teaching data has been created in advance. Such teaching data may be referred to as preliminary teaching data in this specification.

  A robot teaching and reproducing apparatus according to an embodiment of the present invention has a function of adding teaching from an instruction pendant by an operator to the teaching data being reproduced when reproducing the robot based on preliminary teaching data. Prepare. Such a function can be realized by the controller 102 and the teaching pendant 103. As one embodiment, the controller 102 and the teaching pendant are programmed so as to realize the preliminary teaching data correction method described below.

A method for correcting preliminary teaching data according to an embodiment of the present invention will be described with reference to FIG.
In step S301, preliminary teaching data of the robot 101 is created. In the present invention, a method for creating preliminary teaching data is arbitrary. As described above, the teaching data may be created using the teaching pendant 103, or the preliminary teaching data may be created by another method. For example, the preliminary teaching data may be created offline using a simulator. Further, the preliminary teaching data corrected according to the present invention is not necessarily the teaching data of the contact work such as the fitting work as described above.

  In step S302, the test operation of the robot 101 is started. That is, the robot 101 is reproduced according to the preliminary teaching data. It is desirable that the operating speed of the robot 101 can be changed so that the operator can modify the preliminary teaching data with a margin. Therefore, it is desirable that the controller 102 and the teaching pendant 103 are programmed so that the operation speed of the robot can be changed. Further, it is desirable that the operation of the robot 101 can be stopped by a small step movement by inching such as inching, and can be operated again by an instruction operation by the operator. Therefore, the controller 102 and the teaching pendant 103 are preferably programmed so that the robot can perform an inching operation or the like.

  Next, in step S303, the operator can correct the operation of the robot 101 (also referred to as re-teaching) using the JOG key (for example, the operation button group 103a) of the teaching pendant 103 during the test operation of the robot 101. The operator determines whether correction is necessary. The necessity of correction may be determined by visually observing the robot work process, or may be determined from the state amount of the robot 101 displayed on the force control state display unit 113 of the teaching pendant 103 or the like. The method of re-teaching during the test operation of the robot can be performed using the teaching pendant 103 in the same manner as the preliminary teaching described above. That is, the operator operates the operation button group 103a of the teaching pendant 103 while confirming the display of the force control state display unit 113 of the teaching pendant 103, and in addition to the operation of the robot during the test operation in a superimposed manner. It is programmed by the controller 102 so that the robot can be moved.

  It is desirable to have a function that supports these operations when clogging occurs during a mating operation during the test operation, such as when the clogging is eliminated. Therefore, it is desirable that the teaching pendant 103 can teach a plurality of robot operations as one united operation. One collective motion here refers to a motion in which the motion speed or motion direction of the robot changes. Therefore, the motion that is not a single motion refers to a constant velocity linear motion or a constant angular velocity motion of the robot. In the above-described system, teaching of constant velocity linear motion can be performed by the buttons “X +”, “X-”, “Y +”, “Y-”, “Z +”, and “Z-” of the manual operation means 112 of the teaching pendant 103. The teaching of the equiangular velocity motion can be performed by the buttons “Rx +”, “Rx−”, “Ry +”, “Ry−”, “Rz +”, and “Rz−” of the manual operation means 112 of the teaching pendant 103. On the other hand, as an example of teaching one collective action, for example, it is possible to assign a vibration action of a robot to a button or the like of the teach pendant 103 in advance so that the vibration can be taught as one unit action. Can be programmed. As a specific control, the vibration operation of the robot can be realized by adding a sinusoidal force command to the position command during the test operation. It is desirable to be able to change the amplitude and frequency of the sine wave because the frequency of the vibration and the magnitude of the force are often related to the resolution of the clogging. In the system described above, the vibration operation can be taught as a single operation by selecting “vibration force” in the operation mode in the force control setting with the teaching pendant 103. Or, when inserting a fitting part into a part to be fitted in a fitting operation, etc., when the insertion angle does not match and cannot be inserted, etc., a repetitive sine wave operation in one of a plurality of directions You may enable it to perform the teaching which gives. Of course, in other systems, other operations may be set and taught as one collective operation, and the present invention is not limited to the above examples.

  In this way, by teaching a single movement corresponding to the button operation of the robot, the clogging that occurs during insertion and the guidance of the robot can be facilitated, and smooth work execution can be continued.

  In step S303, the teaching given by the operator via the teaching pendant during the test operation is stored in the controller 102 together with the preliminary teaching data. For example, the correction data of the teaching when the robot work has been correctly performed by the operation added in step S303 is stored in a memory area different from the memory area storing the original preliminary teaching. The memory medium itself as hardware may be the same.

  In step S304, the operation of the operation program based on the preliminary teaching is completed. Note that if the robot operation cannot be led to success even if the teaching is given in step S303, the operation may be interrupted and the operation may be started again from step S301 or S302.

  When the final step of the operation is reached while adjusting with the button operation, in step 305, the preliminary teaching data is corrected based on the re-teaching of the operator in step S303. For smooth regeneration operation, it is desirable that the data accompanying the correction is data with a certain degree of continuity, such as a position and force itinerary over time and a position and force iterative over time. . Thus, in the present embodiment, an operation program for the robot 101 can be created based on the teaching data corrected in step S303. The creation of the robot operation program from the corrected teaching data may be executed as described above when the robot operation program is created from the preliminary teaching data. Of course, the robot motion program may be created from the teaching data by other methods, and the format of the motion program is arbitrary.

  As described above, in the present embodiment, even when the robot does not operate as intended by the operator during the test operation of the robot, it is possible to finely correct the movement so that the operator intervenes during the robot operation and the work is successful. it can. Therefore, even when the robot is actually operated, an operation program with a high probability of success can be generated. In addition, since the robot operation program is not generated from a state in which there is no original program, it is easy to lead the robot work to success only by button operation.

Robot operation error determination According to one aspect of the present invention, a function is provided for determining whether a robot has operated as taught during a robot replay operation. Such a function is realized by the controller 102, the teaching pendant 103, and the like. In one embodiment, controller 102 and teach pendant 103 are programmed to implement the method described below.

  In the following description, a determination method according to an embodiment of the present invention will be described on the assumption that the robot is operated based on re-teaching modified from the preliminary teaching. However, the determination function of the present invention can be applied not only when the robot is operated based on the re-teaching, but also when the re-teaching is not performed.

In step S306 of FIG. 12, the robot is replayed based on the operation program created by re-teaching.
In step S307, it is determined whether the current robot work process is the final step of the motion program. If it is not the final step, it is determined in step S308 whether the current work process is correctly performed. The determination in step S308 is performed as follows.

  First, the state quantity (position information, force information, etc.) of the robot when it is re-taught in step S303 (when pre-teaching is not performed) is stored in the controller 102. As an example, FIG. 13 shows the robot tip position acquired during re-teaching and the robot torque acquired during re-teaching in a solid line. Here, it is assumed that these data are acquired as continuous data during re-teaching. Note that the term “continuous” here does not mean mathematically strictly continuous, but means data acquired at a sampling frequency necessary for the determination function of the present invention. Yes. For example, it is possible to set a sampling frequency of about several ms for generating a motion command for each joint axis when generating a motion of the robot. Alternatively, the sampling frequency may be changed according to the operation speed of the robot. For example, the sampling frequency can be increased when the robot operating speed is high, and the sampling frequency can be decreased when the robot operating speed is low. Alternatively, after sampling at a constant sampling frequency, data may be thinned out according to the operation speed of the robot. In this way, excessive memory consumption can be avoided while maintaining sufficient accuracy.

  Since the robot reproduction operation is performed based on the re-teaching data, during the robot reproduction operation, the position command value (that is, the tip position of the robot acquired at the time of re-teaching) and the torque command value (that is, acquired at the time of re-teaching). The torque of the robot), position information from an encoder, etc. and a force detection value from a force sensor are obtained. Therefore, it is determined whether or not the robot is operating properly by comparing the command value related to position and force with the actual measurement value. FIG. 13 shows, as an example, position information and torque information acquired from the robot by broken lines. In an ideal state, the teaching data (that is, the command value) and the reproducing data should match. However, these values are usually different values. The cause is mainly that individual work differences and positions where the work is set differ from work to work.

Whether or not the robot work is appropriately performed can be determined by evaluating the difference between the command value at a certain time and the actually measured value. For example, the following evaluation function can be used.

Here, H1: evaluation value, Fref: force command value, F: force measurement value, Xref: position command value, X: position measurement value, k1, k2: weighting coefficient. The weighting factor can be changed according to the nature of the work. For example, k1 may be relatively increased in a work process in which force control is important, and k2 may be relatively increased in a work process in which position control is important. Either k1 or k2 may be zero. Since the evaluation criteria are generally evaluated with respect to six degrees of freedom of the robot tip, it is assumed that a calculation for matching the coordinate system is performed separately for each command value and each actual measurement value.

  After the calculation of the evaluation value, if the evaluation value H1 is greater than or equal to the reference value, it is assumed that the robot movement or action force has deviated significantly from the command value, and a robot emergency stop or a signal to peripheral devices is issued (S312). . Further, as shown in FIG. 14, the notification means 118 of the teaching pendant 103 may notify the operator that there is an abnormality (S312). When the robot work is not performed correctly, the process may be repeated from step S301 or S302 in the flowchart of FIG.

  In this way, it is possible to determine whether work is being performed correctly at any time during the replaying operation of the robot by sequentially comparing the amount of work performed during the replaying operation with the state amount stored during teaching. Even during the work, by changing or interrupting the work of the robot and peripheral devices, it is possible to avoid a fatal abnormal state such as damage to the robot or the work.

  The evaluation using the above equation (1) can be performed at an arbitrary time during the reproduction operation of the robot. For example, it is possible to periodically determine whether the robot is correctly operated by performing the evaluation using the formula (1) at regular time intervals. Alternatively, the evaluation using the equation (1) may be performed when the robot moves by a fixed distance, that is, not by a fixed time interval, that is, by a fixed movement distance interval of the robot. Or you may change the time interval which evaluates according to the operation speed of a robot.

The above-described determinations in steps S307 to S309 are for determining whether or not there is an abnormality during the operation of the robot, but it is determined as follows whether the operation has been correctly completed within the reference throughout the entire operation process of the robot. be able to. For example, whether or not the command and the actual measurement value from the work start to the end represented by the following expression (2) are within the reference value can be used as a determination criterion.

Here, H2 is an evaluation value, k3 and k4 are weighting coefficients, and Σ is a total sum of evaluation values in parts.
Here again, if an abnormality is detected in the determination, it is necessary to stop the progress to the subsequent steps, so that an emergency stop of the robot and a signal to peripheral devices are issued (S312). Further, as shown in FIG. 14, the notification means 118 of the teaching pendant 103 may notify the operator that there is an abnormality. When the robot work is not performed correctly, the process may be repeated from step S301 or S302 in the flowchart of FIG.

  In this way, it is possible to evaluate success / failure in robot work during playback by comparing the transition of the state quantity of the successful case at the time of teaching acquired by trial and error with the transition of the entire state quantity during the playback operation. Therefore, it is possible to provide a framework in which the operator can automatically perform the success / failure determination of the reliable work execution without special awareness.

  As mentioned above, although this invention was demonstrated along embodiment, this invention is not limited to the above-mentioned embodiment. Further, various features of the above-described embodiments can be separated or combined as long as they do not contradict each other. For example, in the above-described embodiment, the case where the robot operation error determination function is operated based on the teaching data corrected by the present invention has been described. However, the robot operation error determination function is corrected by the present invention. This is not applicable only when the robot is operated based on the taught data. For example, even when the robot is operated based on the preliminary teaching data without correction, the robot operation error determination function can be executed. Such a configuration will be apparent to those skilled in the art from the above description.

101 Robot 102 Controller 103 Teaching Pendant 103a Operation Button Group 103b Display Screen 104 End Effector 105 Force Sensor 106 Force Control Unit 106a Position Control System 106b Impedance Control Operation Unit 106c Impedance Model 106d Speed Decomposition Operation Unit 107 Actuator Drive Amplifier Unit 108 Operation Program Storage Unit 109 operation program execution unit 110a fitting component 110b mated component 111 force control setting unit 112 force control manual operation unit 113 force control state display unit 114 work state storage unit 115 teaching data storage unit 116 teaching data conversion unit 117 Peripheral device 118 Work condition confirmation area

Claims (9)

A robot teaching and reproducing device,
A controller for controlling the movement of the robot;
A teaching pendant connected to the controller for the operator to teach the robot to move,
The controller can add the teaching from the teaching pendant by the operator to the teaching data being reproduced when the robot is performing a reproduction operation based on the teaching data stored in the controller in advance. Playback device.   The teaching reproduction apparatus according to claim 1, wherein the controller stores teaching data including teaching added via a teaching pendant during a reproduction operation of the robot as new teaching data in the controller. Teaching playback device. The teaching reproduction apparatus according to claim 1 or 2,
The teaching reproduction apparatus, wherein the teaching pendant is capable of generating a single motion consisting of a plurality of motions of a robot and adding the single motion to the teaching data being played back. The teaching reproduction device according to any one of claims 1 to 3,
In the playback operation, the controller
Based on at least one of information obtained from a sensor attached to the end effector of the robot and information obtained from an internal sensor of the robot, the state value of the end effector of the robot is calculated,
The evaluation value is calculated using the difference between the state value of the robot end effector stored when the teaching data corresponding to the calculated state value is created and the calculated state value,
A teaching reproduction apparatus that determines whether or not the robot operation is being performed as taught by comparing the evaluation value with a predetermined value. The teaching reproduction device according to claim 4, wherein
In the playback operation, the controller
Storing a plurality of state values of the end effector of the robot based on at least one of information obtained from a sensor attached to the end effector of the robot and information obtained from an internal sensor of the robot;
The second evaluation value is obtained by using the difference between the plurality of state values of the robot end effector stored when the teaching data corresponding to the calculated state value is created and the calculated state values. Operate,
A teaching reproduction device that determines whether or not the robot operation has succeeded as taught by comparing the second evaluation value with a predetermined value. The teaching reproduction apparatus according to claim 4 or 5, wherein
A teaching and reproducing apparatus in which the state value of the end effector of the robot is calculated at a predetermined frequency.   7. The teaching reproduction apparatus according to claim 6, wherein the frequency is relatively large when the operation speed of the robot is large, and is relatively small when the operation speed of the robot is small. Teaching playback device. A robot teaching method,
A step of replaying the robot based on preliminary teaching data created in advance;
And a step of superimposing a further teaching in addition to the preliminary teaching to the robot during the reproducing operation when the robot is performing the reproducing operation according to the preliminary teaching data. A method for creating teaching data for a robot,
A step of replaying the robot based on preliminary teaching data created in advance;
And a step of adding further teaching data to the preliminary teaching data of the robot that is performing the reproducing operation when the robot is performing the reproducing operation according to the preliminary teaching data.