Robot control device and processing system

Abstract

The invention provides a robot control device which can easily teach an operation sequence of supplying a workpiece to a fixing mechanism by a robot, the robot control device controls the robot for supplying and taking out the workpiece to and from the fixing mechanism of a machine tool, and the robot control device comprises a communication part and a control part, the receiving and transmitting unit is used for receiving and transmitting signals for indicating or confirming the action state of the fixing mechanism; a storage unit that stores the specifications of the signals transmitted and received by the communication unit; and a teaching unit that sets the signal transmitted and received by the communication unit.

Description

Technical Field

[0001] The invention relates to a robot control device and a processing system. Background Art

[0002] In the past, robots were used to supply workpieces to industrial machines such as machine tools. In this case, the robot holds the workpiece and supplies the held workpiece to the fixing mechanism of the main spindle of the machine tool. The fixing mechanism for fixing the workpiece uses, for example, a chuck with 2 to 4 claws, or a mechanism that sucks the workpiece by air (see, for example, Patent Document 1). In this system, it is necessary to set a teaching of an operating program, which gradually determines the action sequence of the robot and the fixing mechanism, that is, gradually determines the posture and action speed of the robot, the action of the hand holding the workpiece, the action of the fixing mechanism, etc.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-59069 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In order to obtain sufficient machining accuracy on a machine tool, the center position of the workpiece must be aligned with the center position formed by each claw, and the workpiece must be fed in a direction parallel to the direction of the claw. In order to achieve such an action with a robot, a teaching operation is required to align the center position and posture of the workpiece with the fixing mechanism. In order to correctly teach, even an experienced person needs a lot of time and effort, and it is a very difficult operation for an operator who is not familiar with robots.

[0008] Therefore, a technology that can easily teach the operation sequence for supplying a workpiece to a fixing mechanism using a robot is desired.

[0009] Means for solving problems

[0010] A robot control device of one embodiment of the present invention controls a robot that supplies and removes a workpiece to a fixing mechanism of a machine tool, and the robot control device includes: a communication unit that sends and receives signals for indicating or confirming the operation status of the fixing mechanism; a storage unit that stores specifications of the signals sent and received by the communication unit; and a teaching unit that sets the signals sent and received by the communication unit.

[0011] Effects of the Invention

[0012] According to the present invention, it is possible to easily teach the operation sequence for supplying a workpiece to a fixing mechanism using a robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a block diagram showing the structure of a processing system according to one embodiment of the present disclosure.

[0014] Figure 2 is an example Figure 2 Figure 2 is a diagram of the setting screen for the operation sequence of the machining system.

[0015] Figure 3 is an example Figure 2 Figure 2 is a diagram of a setting screen for the action sequence of workpiece supply of a machining system.

[0016] Figure 4A It is a diagram showing the operation when a workpiece is fixed to the fixing mechanism according to the present embodiment.

[0017] Figure 4B It is a diagram showing the operation when a workpiece is fixed to the fixing mechanism according to the present embodiment.

[0018] Figure 5A It is a diagram showing the operation of correcting the posture error of the workpiece.

[0019] Figure 5B It is a diagram showing the operation of correcting the posture error of the workpiece.

[0020] Figure 5C It is a diagram showing the operation of correcting the posture error of the workpiece.

[0021] Fig. 6A This is a diagram showing an operation of correcting a position error of a workpiece.

[0022] Figure 6B This is a diagram showing an operation of correcting a position error of a workpiece. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 1 is a block diagram showing the structure of a machining system 1 according to an embodiment of the present disclosure. The machining system 1 according to the present embodiment includes a machine tool 10, a numerical controller 20, a robot 30, and a robot controller 40. The machining system 1 supplies and removes a workpiece W to and from the machine tool 10 using the robot 30.

[0024] The machine tool 10 has a fixing mechanism 11 for holding a workpiece W. The fixing mechanism 11 of the present embodiment is a chuck having a base member 111 that rotates together with the spindle, and three gripping claws 112, and the gripping claws 112 are arranged at equal intervals in the circumferential direction on the end surface of the base member 111, and grip the workpiece W by moving (opening and closing) in the radial direction. In addition, the fixing mechanism is not limited to the structure shown in the figure, for example, it may be a structure having more than four gripping claws, and it may also be a structure that holds the workpiece W by suction by vacuum force or magnetic force.

[0025] The numerical controller 20 is a well-known controller for controlling the machine tool 10. The numerical controller 20 outputs a signal indicating the state of the fixing mechanism 11 to the robot controller 40, and operates the fixing mechanism 11 according to a signal instructing the opening and closing of the fixing mechanism 11 received from the robot controller 40.

[0026] The robot 30 is controlled by a robot control device 40 to supply and remove the workpiece W. As the robot 30, a vertical multi-joint robot can be typically used, but other forms of robots can also be used. The robot 30 of this embodiment has: an arm 31, which has a plurality of joints; a gripping mechanism 32, which is provided at the front end of the arm 31 to grip the workpiece W; and a force sense value detector 33, which detects a force sense value, and the force sense value reflects the force acting on the gripping mechanism 32 through interaction with the workpiece W.

[0027] The gripping mechanism 32 has a plurality of gripping fingers 321 for gripping the workpiece W. The force value detector 33 may be a sensor for detecting, for example, force, bending moment, strain, etc., acting on the gripping fingers 321 or the main body of the gripping mechanism 32, or may be configured to detect the current value, torque, etc. of the motor of the drive shaft of the arm 31. That is, the force value detector 33 may be a part of the arm 31. Furthermore, as the force value detector 33, a strain gauge type, electrostatic capacitance type, magnetic type, optical type, or other three-axis or six-axis force sensor may be used.

[0028] The robot control device 40 itself is an embodiment of the robot control device of the present disclosure. The robot control device 40 of this embodiment has a communication unit 41, a storage unit 42, a teaching unit 43, an execution control unit 44, a force sense value acquisition unit 45, an error correction unit 46 and a simulation unit 47. The robot control device 40 can be implemented by one or more computer devices that have, for example, a memory, a processor, an input / output interface, etc., and execute an appropriate control program. Each component of the robot control device 40 is a component that classifies the functions of the robot control device 40, and may not be a component that is clearly distinguished in terms of physical structure and program structure. In addition, in order to realize a user interface, a display device 51 such as a display panel and an input device 52 such as a keyboard and a mouse are connected to the robot control device 40. The display device 51 and the input device 52 may also be provided integrally with the robot control device 40, and the display device 51 and the input device 52 may also be devices provided integrally, such as a touch panel.

[0029] The communication unit 41 transmits and receives signals for indicating or confirming the operation state of the fixing mechanism 11. Specifically, the communication unit 41 receives the following signals from the numerical controller 20: a signal that one of the states of closing the gripping claw 112 of the fixing mechanism 11 and opening the gripping claw 112 is turned on (ON) and the other state is turned off (OFF). In addition, the communication unit 41 sends a signal to the numerical controller 20 requesting the gripping claw 112 of the fixing mechanism 11 to be closed or opened. The specifications of these signals, that is, the form of the signal and the address of the input / output interface used to transmit and receive the signal, may differ depending on the type of the fixing mechanism 11. As an example, depending on the type of the fixing mechanism 11, when the gripping claw 112 is closed, some outputs are turned on (ON) and some outputs are turned off (OFF). In addition, the signal transmitted and received by the communication unit 41 is not limited to an open / close signal, and may also be an analog signal or a signal that conveys information by changing the opening / closing state over time.

[0030] The storage unit 42 stores the specifications of the signals transmitted and received according to the types of the fixing mechanism 11. The types of the fixing mechanism 11 can be determined according to the model thereof, but can also be determined according to a symbol used by the user to identify the fixing mechanism 11, or can also be determined based on a group set according to the signal specifications. In other words, each of the plurality of fixing mechanisms 11 can be handled as a separate type, or a group (group) including the fixing mechanisms 11 of a plurality of models can be handled as one type.

[0031] As an example, Figure 2As shown, the teaching unit 43 may be configured to arrange icons representing the action sequence of each unit action, such as the supply action of the workpiece W and the removal action of the workpiece W, in the order to be executed on the space (execution line) set on the display device 51, thereby automatically setting various parameters, which determine the action sequence of the robot 30 that realizes the unit action shown by each icon, that is, providing a user interface that can easily teach the action of the robot 30. As parameters for determining the action sequence, the coordinates of the reference point of the robot 30, the position and speed of each drive axis (especially the speed of approaching the fixing mechanism 11), the state of the gripping finger 321, etc. can be cited. In addition, the teaching unit 43 may also be configured to switch the screen displayed on the display device 51 to a setting screen for allowing the user to input the minimum information required to set the action sequence of the unit action when the icon representing the unit action is configured or the icon representing the unit action is selected, as needed.

[0032] When setting the action sequence of supplying or removing the workpiece W, the teaching unit 43 refers to the storage unit 42 and sets the signal sent and received by the communication unit 41 according to the type of the fixing mechanism 11. In addition, the teaching unit 43 accepts the user's input and sets the action sequence of supplying or removing the workpiece W by the fixing mechanism 11 and the robot 30 based on the accepted input. Therefore, when the icon representing the supply or removal of the workpiece W is arranged on the execution line, the teaching unit 43 displays a setting screen that prompts the user to input the minimum required amount. Figure 3 , a setting screen 1000 for setting the supply operation of the workpiece W displayed on the display device 51 by the teaching unit 43 is illustrated. The teaching unit 43 is configured to set the operation sequence of the supply operation of the workpiece W on a single setting screen 1000 .

[0033] The supply action of the workpiece W includes the following steps: causing the numerical control device 20 to open the gripping claw 112 of the fixing mechanism 11; positioning the front end of the robot 30 to a supply start position, wherein the supply start position is set to place the workpiece on the rotating axis of the spindle of the machine tool 10; causing the robot 30 to move the workpiece W in the axial direction of the fixing mechanism 11 by more than the minimum insertion length and insert it into the fixing mechanism 11; and causing the numerical control device 20 to close the gripping claw 112 of the fixing mechanism 11.

[0034] The teaching unit 43 automatically sets the method of signals sent and received by the communication unit 41 and the address of the input / output interface according to the type of the fixing mechanism 11 in the process of opening the gripping claw 112 and the process of closing the gripping claw 112. Although the teaching unit 43 may be configured to obtain the type of the fixing mechanism 11 from the numerical controller 20, in order to use the existing numerical controller 20, the teaching unit 43 is configured to determine the type of the fixing mechanism 11 by accepting the input of the user. Figure 3The setting screen 1000 displays a drop-down menu 1001 for the user to input the fixing mechanism.

[0035] The teaching unit 43 is used to teach the process of positioning the robot 30 at the supply start position, that is, to set the operation parameters required by the execution control unit 44. Figure 3 The setting screen 1000 of the teaching unit 43 displays a drop-down menu 1002, which allows the user to select from a plurality of default values ​​of the supply start position, specifically, to select the number of the preset coordinates. In addition, the setting screen 1000 displayed by the teaching unit 43 includes a button 1003, which causes a pop-up window for correcting the default value (coordinates) of the supply start position. The pop-up window by operating the button 1003 may include a plurality of text boxes, which respectively display the (X, Y, Z, W, P, R) values ​​that determine the position and direction of the front end reference point of the robot 30 in an editable manner.

[0036] The teaching unit 43 displays a text box 1004 on the setting screen 1000 , and the text box 1004 allows the user to input the minimum insertion length in the process of inserting the workpiece W into the fixing mechanism 11 .

[0037] In addition, the teaching unit 43 displays a test execution button 1005 and a button 1006 on the setting screen 1000. The test execution button 1005 starts the following process: the action sequence is executed by the execution control unit 44, and the action sequence is optimized based on the force sense value by the error correction unit 46. Figure 3 As shown, a window for adjusting parameters such as speed and judgment threshold when optimizing the action sequence based on the force sense value is popped up and displayed.

[0038] The execution control unit 44 causes the fixing mechanism 11 and the robot 30 to execute the operation sequence according to the sequence taught by the teaching unit 43. The execution control unit 44 is preferably configured to immediately reflect the operation sequence corrected by the error correction unit 46 and cause the fixing mechanism 11 and the robot 30 to operate.

[0039] The force sense value acquisition unit 45 acquires the force sense value reflecting the force generated by the interaction between the workpiece W and the robot 30 from the force sense value detector 33 when executing the action sequence. That is, the force sense value acquisition unit 45 acquires the magnitude and direction of the force that causes the workpiece W to push back the gripping mechanism 32 of the robot 30 due to the contact of the workpiece W with the fixing mechanism 11.

[0040] The error correction unit 46 corrects the errors in the position and posture of the robot in the operation sequence based on the force sense value acquired by the force sense value acquisition unit, and optimizes the operation sequence. The error correction by the error correction unit 46 will be described in detail below.

[0041] Figure 4A and Figure 4B 1 is a diagram showing the operation when the workpiece W of the present embodiment is supplied to the fixing mechanism 11 and fixed. When the robot 30 supplies the workpiece W to the fixing mechanism 11, it moves in the direction L of supplying the workpiece W to the fixing mechanism 11. Then, when the cylindrical workpiece W is supplied to the vicinity of the center position of the gripping claw 112 by the robot 30 and the gripping claw 112 is closed by the machine tool 10, the workpiece W is fixed to the center position of the base member 111.

[0042] If the workpiece W can be supplied to the base member 111 of the fixing mechanism 11 in a correct position and posture, when the gripping claws 112 are closed, as shown in FIG. Figure 4A As shown, the base member 111 coincides with the central axis of the workpiece W. In this case, the machine tool 10 can obtain good machining accuracy.

[0043] However, when the workpiece W is fed, if the error in the position and posture of the workpiece W relative to the base member 111 is large, when the grip claws 112 are closed, as shown in FIG. Figure 4B As shown, the base member 111 may be fixed in a state where the center axis of the workpiece W is offset from that of the workpiece W. In this case, the machine tool 10 cannot obtain good machining accuracy.

[0044] Therefore, the error correction unit 46 performs a process (force sense value control) of correcting the error between the position and posture of the workpiece W and the fixing mechanism 11 as described below.

[0045] Figure 5A , Figure 5B and Figure 5C : is a diagram showing the action of correcting the posture error of the workpiece W. Figure 5A As shown, the robot control device 40 controls the robot 30 to position the workpiece W on the base member 111. Figure 5A In the example shown, the workpiece W has a posture error with respect to the base member 111. Then, the error correction unit 46 of the robot control device 40 executes force sense value control for correcting parameters of the operation sequence based on the force sense value.

[0046] Specifically, the error correction unit 46 controls the robot 30 to push the workpiece W to any one of the gripping claws 112 during the force sense value control. That is, the error correction unit 46 controls the robot 30 to push the workpiece W to the fixing mechanism 11 in a direction substantially orthogonal to the direction in which the workpiece W is supplied to the fixing mechanism 11 during the force sense value control.

[0047] Figure 5B 1 is a diagram showing the action of correcting the posture of the workpiece W when the workpiece W is pushed against the gripping claw 112. Figure 5BAs shown in FIG. 1 , when the robot 30 pushes the workpiece W to the gripping claw 112, a moment M1 is generated around the center (rotation center C) of the contact surface between the workpiece W and the gripping claw 112. Here, the reaction force to the force that pushes the workpiece W to the gripping claw 112 is set as force F, and the distance from the rotation center C of the workpiece W to the position where the force F acts is set as distance r2, and the moment M1 is expressed as [M1=r2×F].

[0048] When the force sense detector 33 detects the torque M1, the error correction unit 46 performs force sense control so that the torque of pressing the workpiece W to the fixing mechanism 11 becomes 0. That is, when the force sense detector 33 detects the torque M1, the error correction unit 46 rotates the workpiece W around the rotation center C through the robot 30 to correct the posture of the workpiece W. Figure 5C As shown, the workpiece W rotates in a direction in which the moment M1 decreases, and the error in the posture of the workpiece W is corrected.

[0049] Fig. 6A and Figure 6B : is a diagram showing the action of correcting the position error of the workpiece W. Fig. 6A As shown, the robot control device 40 controls the robot 30 to position the workpiece W on the end surface of the base member 111. Fig. 6A In the example shown, a position error occurs in the workpiece W relative to the base member 111. Then, the error correction unit 46 performs force sense value control.

[0050] Specifically, the error correction unit 46 uses the communication unit 41 to send a control signal to the numerical controller 20 during the force sense value control, so that the machine tool 10 performs the action of closing the gripping claws 112 of the fixing mechanism 11. That is, the numerical controller 20 operates the fixing mechanism 11 in conjunction with the force sense value control of the robot 30 and the robot controller 40.

[0051] When the holding claw 112 is closed, Figure 6B As shown, the workpiece W is subjected to a force F1 in a direction substantially orthogonal to the direction in which the workpiece W is supplied to the fixing mechanism 11 by the gripping claws 112. Then, when the force sense value detector 33 detects the force F1, the error correction unit 46 corrects the position of the workpiece W by moving the workpiece W in a direction in which the force F1 becomes smaller through the action of the force sense value control.

[0052] Thus, in the force sense value control, when a position error occurs in the workpiece W when the grip claws 112 are closed, the workpiece W moves in a direction to eliminate the position error due to the force sense value control. In addition, the force sense value control adopts, for example, impedance control, damping control, etc., but is not limited thereto.

[0053] In addition, the machine tool 10 may repeat the operation of the fixing mechanism 11 a preset number of times. The error correction unit 46 causes the fixing mechanism 11 to repeat the opening and closing of the gripping claw 112 a predetermined number of times during the execution of the force sense value control. Thus, the error of the position and posture of the workpiece W is corrected every time the gripping claw 112 is opened and closed. In addition, when the fixing mechanism 11 is an adsorption mechanism, the machine tool 10 causes the adsorption and release of the workpiece W to repeat a predetermined number of times during the execution of the force sense value control. Thus, the error of the position and posture of the workpiece W is corrected every time the adsorption and release are performed.

[0054] In addition, the robot 30 or the machine tool 10 may also include a movement amount detector for detecting the movement amount of the workpiece W. When the fixing mechanism 11 is actuated, the error correction unit 46 repeats the force sense value control until the movement amount of the workpiece W becomes less than a predetermined distance or a predetermined angle.

[0055] Furthermore, when an excessive force or moment is generated during the operation of the fixing mechanism 11, the machine tool 10 may release the workpiece W through the fixing mechanism 11 and then operate the fixing mechanism 11 again to fix the workpiece W through the fixing mechanism 11. That is, when the detection value of the force sense value detector 33 is greater than a predetermined value indicating an excessive force or moment during the operation of the fixing mechanism 11, the machine tool 10 may interrupt the operation of the fixing mechanism 11, release the workpiece W through the fixing mechanism 11, and then operate the fixing mechanism 11 again to fix the workpiece W through the fixing mechanism 11.

[0056] Furthermore, although the method of closing the fixing mechanism 11 after pressing the workpiece W against the fixing mechanism 11 has been described, the workpiece W may be pressed after closing the fixing mechanism 11 .

[0057] The simulation unit 47 performs a simulation of the action sequence and displays the simulation result. The simulation unit 47 preferably displays the calculated force sense value together with the simulation result. For example, it can also be configured so that in addition to displaying the force sense value, the parameters such as the speed and contact threshold in the simulation can also be displayed together with the simulation result. The display of the simulation result of the simulation unit 47 is preferably performed as a part of the setting screen 1000. That is, it is preferably configured so that the space that can be used to display the simulation result is ensured by the teaching unit 43. The simulation unit 47 can also be configured so that when a problem occurs in the simulation, the parameter that becomes an abnormal value among the displayed parameters can be displayed so that it can be identified, for example, by highlighting. In this way, the user can easily grasp the parameter that may be the cause of the problem.

[0058] The embodiments of the present disclosure are described above, but the present invention is not limited to the embodiments described above. In addition, the effects described in the embodiments described above are only preferred effects produced by the present invention, but the effects of the present invention are not limited to the effects described in the embodiments described above.

[0059] As an example, the robot control device of the present invention may be configured so that the operation sequence for taking out a workpiece is similarly set.

[0060] Explanation of symbols

[0061] 1. Processing system

[0062] 10Machine Tools

[0063] 11Fixed mechanism

[0064] 111 base parts

[0065] 112 grip claw

[0066] 20 Numerical control device

[0067] 30 Robots

[0068] 31 arms

[0069] 32 Holding mechanism

[0070] 321 holding finger

[0071] 33 Force sense detector

[0072] 40Robot control device

[0073] 41 Ministry of Communications

[0074] 42 Storage

[0075] 43 Teaching Department

[0076] 44Execution Control Unit

[0077] 45 Force Sense Acquisition Department

[0078] 46 Error Correction Unit

[0079] 47 Simulation Department

[0080] W workpiece.

Claims

1. A robot control device for controlling a robot for supplying and removing a workpiece to a fixing mechanism of a machine tool, characterized in that: The robot control device comprises: a communication unit for transmitting and receiving a signal for indicating or confirming the operation status of the fixing mechanism; a storage unit storing specifications of the signal transmitted and received by the communication unit; and A teaching unit is configured to set the signal transmitted and received by the communication unit.

2. The robot control device according to claim 1, characterized in that: The teaching unit receives input from a user, and sets an operation sequence of the fixing mechanism and the robot for supplying or removing the workpiece based on the received input.

3. The robot control device according to claim 2, characterized in that: The robot control device comprises: an execution control unit, which enables the fixing mechanism and the robot to execute the action sequence; a force sense value acquisition unit that acquires a force sense value when executing the action sequence, the force sense value reflecting a force generated by the interaction between the workpiece and the robot; as well as An error correction unit corrects errors in the position and posture of the robot in the operation sequence based on the force sense value acquired by the force sense value acquisition unit.

4. The robot control device according to claim 3, characterized in that: The teaching unit determines the type of the fixing mechanism based on the received input.

5. The robot control device according to claim 4, characterized in that: The execution control unit sets parameters based on the type of the fixing mechanism.

6. The robot control device according to any one of claims 2 to 5, characterized in that: The robot control device includes a simulation unit that executes a simulation of the operation sequence and displays a result of the simulation.

7. The robot control device according to any one of claims 2 to 6, characterized in that: The teaching unit is configured to be able to set the operation sequence on a single setting screen.

8. The robot control device according to claim 7, characterized in that: The teaching unit is configured to set the motion parameters of the robot to preset default values, and the setting screen includes a button for causing a pop-up window for modifying the default values ​​to be displayed.

9. A processing system, characterized in that: have: The robot control device according to any one of claims 1 to 8; A machine tool having the fixing mechanism; and The robot is controlled by the robot control device to supply and remove the workpiece to the fixing mechanism.

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