JP2023135856A - remote control system - Google Patents

Abstract

To provide a remote control system that enables a worker to work appropriately through remote control.SOLUTION: A work system 1 comprises a remote control part 31 that enables a worker to perform welding work to a work-piece by remotely controlling a torch 14, and a control device 4 that makes the remote control part 31 output force according to a position of the torch 14. The control device 4 makes the remote control part 31 output restoring force that gradually becomes larger as a tip of the torch 14 separates from a central plane to be welded.SELECTED DRAWING: Figure 4

Description

The present invention relates to a remote control system.

2. Description of the Related Art Conventionally, remote control systems have been known in which a worker remotely operates a work robot to perform work such as welding.
In the remote control system described in Patent Document 1, a collision between the working robot and the obstacle is avoided by making the worker perceive a reaction force when the robot arm approaches the obstacle.

Japanese Patent Application Publication No. 2012-11498

However, while the reaction force generated when a work robot approaches an obstacle is effective in avoiding collision with the obstacle, it is not effective when, for example, you want to move the robot arm along a predetermined reference line. It may not function properly and you may not be able to work properly.
The present invention has been made in view of the above circumstances, and an object of the present invention is to enable a remote worker to perform work suitably.

The remote control system according to the present invention includes:
a remote control means for remotely controlling a torch to perform welding work on a workpiece;
force sense control means for causing the remote control means to output a force according to the position of the torch;
Equipped with
The force sense control means causes the remote control means to output a first force that gradually increases as the tip of the torch moves away from a predetermined reference position.

According to the present invention, a remote worker can suitably perform work.

1 is a conceptual diagram showing a work system according to an embodiment. FIG. 1 is a perspective view of a welding vehicle according to an embodiment. FIG. 3 is a diagram showing the vicinity of the tip of the torch according to the embodiment. FIG. 1 is a block diagram showing a schematic control configuration of a work system according to an embodiment. It is a flowchart which shows the flow of operation support processing concerning an embodiment. FIG. 3 is a diagram for explaining operation support processing according to the embodiment. FIG. 3 is a diagram for explaining operation support processing according to the embodiment. (a) A calculation model for calculating the distribution of reaction force and restoring force in the X direction, and (b) The calculation result showing an example of the distribution of reaction force, restoring force, and their resultant force in the X direction. It is a graph. FIG. 7 is a diagram for explaining a modification of the restoring force reference position.

Embodiments of the present invention will be described in detail below with reference to the drawings.

[Work system configuration]
FIG. 1 is a conceptual diagram showing a work system 1 according to this embodiment.
As shown in this figure, a work system 1 is an example of a remote control system according to the present invention, and is used to cause a welding vehicle 10 to perform welding work by remote control by a worker (operator) WK. Specifically, the work system 1 includes a welding vehicle 10, a remote control device 3, and a control device 4.

FIG. 2 is a perspective view of the welding vehicle 10.
As shown in this figure, a welding vehicle 10 is a welding robot that welds workpieces to be welded, that is, plate materials 20 together, while moving in the direction of an arrow α on an iron plate (steel plate) 20 installed horizontally. It is. After welding, this plate material 20 is used, for example, as a floor.
In addition, in the following, each direction of XYZ that is orthogonal to each other is set as shown in each figure. As an example, the XY plane is horizontal and the Z direction is vertical. Further, the moving direction (α direction) of the welding vehicle 10 is the -Y direction. However, the moving direction of welding vehicle 10 is not limited to the -Y direction, and may be, for example, the opposite direction (+Y direction).

The welding vehicle 10 of this embodiment performs V-shaped groove butt welding on two plate materials 20 by arc welding. In other words, two plates (steel plates) 20 whose ends are cut diagonally and have a groove surface (side surface 20a) are butted together to form a joint with a V-shaped groove 21, and welding is performed to fill this groove (groove) 21. (See Figure 7). A ceramic backing material 25 is placed at the bottom of the groove 21 (not shown in FIG. 2), and the surface of the backing material 25 serves as the bottom surface 25a of the groove 21. The groove 21 has a total length of 5 m or more, a width of about 5 mm, and a depth of about 10 mm, depending on the use of the plate material 20, for example. Further, in this embodiment, the longitudinal direction of the groove 21 is parallel to the Y direction, the width direction of the groove 21 is parallel to the X direction, and the depth direction of the groove 21 is parallel to the Z direction.
The welding vehicle 10 welds the plate materials 20 together by melting a wire (filler material: not shown) with a torch 14, which will be described later, and filling the grooves 21 with the melted material.
In addition, below, the surface of a workpiece|work, ie, the side surface 20a and bottom surface 25a of the groove|channel 21, and the upper surface 20b of the board|plate material 20, may be called "work surface Sw."

Specifically, the welding vehicle 10 includes a vehicle body 11, a welding device 12, four wheels 18, and a drive unit 16 that rotationally drives each wheel 18.

The vehicle body 11 has a rotation support portion (support portion) 13 that rotatably supports each wheel 18 (wheel body).
Furthermore, a drive section 16 is fixed to the outside of each rotation support section 13. The drive unit 16 is composed of, for example, a geared motor, and is connected to the wheels 18 . Then, by operating the drive unit 16, the wheels 18 can be rotated. This rotation allows the welding vehicle 10 to run, for example, using the upper surface 20b (front surface) of the plate material 20 as a running surface.
In addition, although the number of wheels 18 arranged is four in this embodiment, it is not limited to this.

A welding device 12 is mounted on the vehicle body 11. The welding device 12 includes a torch (welding torch) 14 and a displacement mechanism 15 that supports the torch 14 in a movable manner.
The torch 14 is a working unit that performs welding work on the plate material 20. The torch 14 of this embodiment is configured to perform arc welding by arc discharge. This arc welding allows the plate materials 20 to be easily and firmly welded together.

The displacement mechanism 15 includes a first movement mechanism 151 , a second movement mechanism 152 , a third movement mechanism 153 , and a rotation mechanism (angle adjustment mechanism) 154 .
The first moving mechanism 151 is a mechanism that moves the torch 14 with respect to the vehicle body 11 in a direction parallel to the arrow α direction (Y direction).

A second moving mechanism 152 is connected to the first moving mechanism 151 . The second moving mechanism 152 is a mechanism that moves the torch 14 relative to the vehicle body 11 in a direction (X direction) orthogonal to the direction of arrow α.
A third moving mechanism 153 is connected to the second moving mechanism 152 . The third moving mechanism 153 is a mechanism that moves the torch 14 in the vertical direction (Z direction) with respect to the vehicle body 11.

A rotating mechanism 154 is connected to the third moving mechanism 153 . The rotation mechanism 154 is connected to the torch 14 via a connecting portion 155. This rotation mechanism 154 is a mechanism for rotating the torch 14 around a horizontal axis with respect to the vehicle body 11.
With the displacement mechanism 15 having such a configuration, the position and attitude of the torch 14 with respect to the joint between the plate materials 20 can be changed as appropriate, and welding can be easily performed.

FIG. 3 is a diagram showing the vicinity of the tip of the torch 14.
As shown in this figure, an imaging section 17 is connected and supported by the torch 14 via a connecting member 171. The imaging unit 17 is configured with, for example, a CMOS camera or a CCD camera, and images an object to be photographed including the torch 14 and the plate material 20 (groove 21), and obtains image information thereof. The acquired image information is transmitted to the control device 4. The imaging unit 17 of this embodiment photographs the welding part around the torch 14 from diagonally above on the traveling direction (-Y direction) side of the welding vehicle 10.
Further, the torch 14 also supports a laser beam irradiation section 19 . The laser beam irradiation unit 19 irradiates the plate material 20 including the grooves 21 with a laser beam LB. The laser beam irradiation unit 19 of this embodiment is arranged at the same position as the torch 14 in the X direction and adjacent to the torch 14 in the Y direction. Thereby, the laser beam LB from the laser beam irradiation unit 19 is irradiated with its center at the same position as the torch 14 in the X direction. Moreover, the laser light irradiation unit 19 of this embodiment is configured to irradiate line laser light along the X direction as the laser light LB. This allows the imaging unit 17 to accurately detect the shape of the work surface Sw.

FIG. 4 is a block diagram showing a schematic control configuration of the work system 1. As shown in FIG.
As shown in this figure, the remote control device 3 is a device that allows a worker WK to remotely control the welding vehicle 10 in a separate room or the like apart from the welding vehicle 10. Therefore, the work system 1 is a leader-follower system in which the welding vehicle 10 follows the operations of the worker WK without delay.
The remote control device 3 includes a remote control section 31 that can be held by the worker WK and apply force in a desired direction.

The worker WK can move the torch 14 in the Y direction via the first moving mechanism 151 of the displacement mechanism 15 by applying force in the Y direction (direction corresponding to the Y direction) and operating the remote control unit 31. can.
Similarly, if the worker WK applies force in the X direction (corresponding direction) and operates the remote control unit 31, the torch 14 is moved in the can be done.
Further, if the worker WK applies force in the Z direction (direction corresponding to) and operates the remote control unit 31, the torch 14 is moved in the Z direction via the third moving mechanism 153 of the displacement mechanism 15. be able to.
The remote control unit 31 can operate the displacement mechanism 15 to perform remote control to move the torch 14 in the X direction, the Y direction, and the Z direction. Further, the remote control section 31 is a force sense presentation device that feeds back a reaction force according to the distance between the torch 14 and the workpiece, as described later. The form of the remote control section 31 is not particularly limited, and for example, a joystick or the like can be used.

The control device 4 is composed of, for example, a personal computer. The control device 4 is electrically connected to the welding vehicle 10, the remote control device 3, and the welding vehicle 10, and centrally controls the operation of each part of the work system 1. Further, the control device 4 is an example of a force sense control means according to the present invention, and causes the remote control section 31 to output a force according to the position of the torch 14. Note that the "electrical connection" may be either a wireless connection or a wired connection.
Specifically, the control device 4 includes a CPU 41 , a storage section 42 , a communication section 43 , an input section 44 , a display section 45 , and an audio output section 46 .

The CPU 41 operates each part of the control device 4 based on the operation contents of the input unit 44, develops a program stored in advance in the storage unit 42, and executes various processes in cooperation with the developed program. I do things.
The storage unit 42 is a memory configured with a RAM (Random Access Memory), a ROM (Read Only Memory), etc., and stores various programs and data, and also functions as a work area for the CPU 41.

The communication unit 43 is a communication device that can transmit and receive various information between the remote control device 3 and the welding vehicle 10. Specifically, the communication unit 43 receives an input signal, that is, a command, from the remote control device 3 and transmits the input signal to the communication unit 101 of the welding vehicle 10.
The input unit 44 is an operation means through which the worker WK performs various operations to operate the control device 4, and includes, for example, a pointing device such as a mouse and a keyboard.

The display section 45 is composed of, for example, a liquid crystal display, an organic EL display, or other display, and displays various information based on display signals from the CPU 41. The display unit 45 of this embodiment displays images captured by the imaging unit 17 and the like. The worker WK can perform remote control while visually checking the image displayed on the display unit 45. Note that the display section 45 may be a touch panel that also serves as a part of the input section 44.
The audio output unit 46 is composed of, for example, a speaker, and outputs various sounds based on the audio output signal from the CPU 41.

Welding vehicle 10 has a communication section 101 and a control section 102 in addition to the above configuration.
The communication unit 101 is a communication device that can send and receive various information to and from the communication unit 43 of the control device 4 . Specifically, the communication unit 101 receives input signals from the remote control device 3 transmitted from the communication unit 43 of the control device 4, and transmits image information etc. acquired by the imaging unit 17 to the communication unit of the control device 4. 43.
Control unit 102 controls the operation of each part of welding vehicle 10 based on the input signal from remote control device 3 that communication unit 101 receives. Thereby, welding vehicle 10 is remotely controlled according to the input signal.

[Operation support processing]
Next, operation support processing executed during welding work by the work system 1 will be described.
FIG. 5 is a flowchart showing the flow of the operation support process, and FIGS. 6 and 7 are diagrams for explaining the operation support process.
The operation support process is a process that assists the worker WK in the welding work performed by remotely controlling the welding vehicle 10 by facilitating the worker WK's understanding of the work situation. This operation support process is executed, for example, by the CPU 41 of the control device 4 reading out and developing the corresponding program from the storage unit 42 based on an input operation by the worker WK.

As shown in FIG. 5, when the operation support process is executed, the CPU 41 of the control device 4 first starts groove welding of the workpiece by remote control by the worker WK (step S1).
In this welding work, the CPU 41 transmits to the welding vehicle 10 an input signal corresponding to the operation content of the remote control unit 31 by the worker WK. Control section 102 of welding vehicle 10 operates each section based on the received input signal. Thereby, the welding vehicle 10 moves along the groove 21 while supplying the wire downward from the tip (lower end) of the torch 14 and melts the wire to weld the plate materials 20 together.
Also, at this time, the CPU 41 causes the display unit 45 to display in real time an image of the welding area around the torch 14 taken by the imaging unit 17 of the welding vehicle 10. The photographed image (video) of this welding section shows the wire and workpiece (groove 21) supplied from the tip of the torch 14, the arc generated between them, and the molten pool (front molten pool) in which the wire was melted by the arc. included. The worker WK operates the remote control unit 31 while visually checking the photographed image displayed on the display unit 45 and confirming the welding situation and state.
In this specification, unless otherwise specified, the term "torch 14" includes a wire supplied from its tip. That is, the "tip of the torch 14" refers to the tip of the wire when the wire is being supplied, and the "collision between the torch 14 and the workpiece" includes the collision between the wire and the workpiece.

ここで、P_iは、個数がN_ROIであるＲＯＩ内のｉ番目の点の位置ベクトルであり、P_rは、トーチ１４先端の位置ベクトルである。また、式（１）の係数Ｋは対角行列K＝diag(kx,ky,kz)であり、kx，ky，kzの値の選び方によって力ベクトルの各成分に異方性を生じさせられるようにしている。kx，ky，kzの値は、例えば、ワークとの距離を同一にして、トーチ１４先端を開先中心と開先面の中心にそれぞれ置いたときの力の大きさが同じになるように定める。この値は作業者ＷＫが随時変更できる。
なお、上記式（１）では、反力Ｆｂがトーチ１４先端位置とワークとの距離（P_r－P_i）に反比例（－１乗）することとしたが、この指数は－１以下の実数（例えば－１．５乗、－２乗、－３乗等）としてもよい。例えば、この指数を－２乗や－３乗にすると、トーチ１４先端が開先面に近づくに連れて、反力Ｆｂがより急峻に強くなる。 Next, the CPU 41 calculates a reaction force Fb that gradually increases as the tip of the torch 14 approaches the workpiece, and causes the remote control unit 31 to output the reaction force Fb (step S2). The reaction force Fb is an example of the second force according to the present invention.
Specifically, as shown in FIG. 6, a region of interest (ROI) centered on the nearest point to the tip of the torch 14 is extracted from the point cloud data, and the ROI is calculated as a weighted sum of vectors directed from each point toward the tip of the torch 14. Find the force Fb. Point cloud data on the work surface Sw is acquired by the laser beam irradiation unit 19 at any time. However, point cloud data obtained in advance using the laser beam irradiation unit 19 (or a CAD model of the workpiece) may be used. The ROI is formed into a square shape by extracting a predetermined number of points in each of the X and Y directions, centering on the point closest to the tip of the torch 14 from among the point group. Then, it is assumed that each point of the ROI exerts a force on the tip of the torch 14 whose magnitude is inversely proportional to the distance from itself to the tip of the torch 14, and the reaction force Fb is determined as the resultant force using the following equation (1).

Here, P _i is the position vector of the i-th point in the ROI whose number is N _ROI , and P _r is the position vector of the tip of the torch 14. In addition, the coefficient K in equation (1) is a diagonal matrix K=diag(kx,ky,kz), and it is possible to create anisotropy in each component of the force vector by selecting the values of kx, ky, and kz. I have to. For example, the values of kx, ky, and kz are determined so that the magnitude of the force is the same when the tip of the torch 14 is placed at the center of the groove and the center of the groove surface, respectively, with the distance from the workpiece being the same. . This value can be changed by the worker WK at any time.
Note that in the above equation (1), the reaction force Fb is inversely proportional (to the -1 power) to the distance (P _r - _{P i} ) between the tip position of the torch 14 and the workpiece, but this exponent is a real number less than -1. (For example, it may be set to the -1.5 power, -2 power, -3 power, etc.). For example, when this index is raised to the -2 or -3 power, the reaction force Fb becomes steeper and stronger as the tip of the torch 14 approaches the groove surface.

In this way, the reaction force Fb output from the remote control unit 31 is inversely proportional to the distance between the tip of the torch 14 and the work surface Sw. Therefore, the worker WK who operates the remote control unit 31 feels a stronger reaction force Fb as the tip of the torch 14 approaches the workpiece. That is, the worker WK can sense the distance between the torch 14 and the workpiece by the reaction force Fb fed back to the remote control unit 31. The torch 14 never comes closer to the work surface Sw than the collision avoidance surface Sc located at a predetermined distance from the work surface Sw (see FIG. 7(b)). Thereby, the worker WK is made aware of the approach of the torch 14 to the work surface Sw, and a collision between the torch 14 and the work can be suitably prevented.

ここで、P_rは、トーチ１４先端のＸ方向位置であり、Pcは、溶接中心面Ｃ（開先中心）のＸ方向位置である。また、ｋは任意の係数である。この値は作業者ＷＫが随時変更できる。 Next, as shown in FIG. 5, the CPU 41 calculates a restoring force Fc that gradually increases as the tip of the torch 14 moves away from the welding center plane C, and causes the remote control unit 31 to output it (step S3). Here, the welding center plane C is a reference plane along the welding direction (Y direction), as shown in FIGS. It is a plane that passes through and is parallel to the YZ plane. Further, the restoring force Fc is an example of the first force according to the present invention.
Specifically, the CPU 41 calculates the restoring force Fc using the following equation (2).

Here, _Pr is the position in the X direction of the tip of the torch 14, and Pc is the position in the X direction of the welding center plane C (groove center). Further, k is an arbitrary coefficient. This value can be changed by the worker WK at any time.

In this way, the restoring force Fc output from the remote control unit 31 is proportional to the distance between the tip of the torch 14 and the welding center plane C. Therefore, the worker WK who operates the remote control unit 31 feels a stronger restoring force Fc as the tip of the torch 14 moves away from the welding center plane C. That is, the worker WK can sense the distance between the torch 14 and the welding center plane C by the restoring force Fc fed back to the remote control unit 31. Thereby, the torch 14 can be suitably held near the welding center plane C.

Here, a calculation example will be shown in which the distribution in the X direction (the width direction of the groove 21) is obtained for each of the reaction force Fb and the restoring force Fc.
FIG. 8(a) is a diagram showing the calculation model. As shown in this figure, this calculation uses a simplified model in which the tapered side surface 20a is a plane perpendicular to the X direction (double-dashed line in the figure), and both the reaction force Fb and the restoring force Fc are It is assumed that this depends only on the position in the X direction.

FIG. 8(b) is a graph showing an example of the distribution of the reaction force Fb, the restoring force Fc, and the resultant force F in the X direction, which is the calculation result.
As shown in this figure, the reaction force Fb remains small until the torch 14 approaches the side surface 20a of the groove 21 considerably, and then rapidly increases when the torch 14 approaches the side surface 20a. Therefore, although it is effective in preventing collision between the torch 14 and the side surface 20a, it does not function very effectively in keeping the torch 14 near the welding center plane C (X=0).
In this regard, since the restoring force Fc increases in proportion to the distance between the tip of the torch 14 and the welding center plane C, it functions effectively to hold the torch 14 near the welding center plane C.
Therefore, by making the worker WK perceive the resultant force F of the reaction force Fb from the workpiece surface Sw (side surface 20a) and the restoring force Fc to the welding center surface C, the worker WK can avoid the collision between the torch 14 and the workpiece. The torch 14 can be held in the vicinity of the welding center plane C while avoiding this.

Next, as shown in FIG. 5, the CPU 41 determines whether or not to end the operation support process (step S4), and if it is determined not to end (step S4; No), the process proceeds to step S1 described above. Transfer processing and continue welding work.
If it is determined that the operation support process is to be ended, for example due to the end of the welding work (step S4; Yes), the CPU 41 ends the operation support process.

[Technical effects of this embodiment]
As described above, according to the present embodiment, the restoring force Fc that gradually increases as the tip of the torch 14 moves away from the welding center plane C (groove center) is output to the remote control unit 31.
Thereby, the worker WK who operates the remote control unit 31 can hold the torch 14 near the welding center plane C by sensing the restoring force Fc. Therefore, the worker WK can move the torch 14 along a desired trajectory to suitably perform welding work. In addition to improving welding quality, it can also be effectively used as a training tool for learning welding skills.

Further, according to the present embodiment, in addition to the restoring force Fc, a reaction force Fb that gradually increases as the tip of the torch 14 approaches the workpiece is output to the remote control unit 31.
The reaction force Fb effectively functions to prevent collision between the torch 14 and the workpiece. Therefore, by sensing the resultant force F of the restoring force Fc and the reaction force Fb, the worker WK can hold the torch 14 near the welding center plane C while avoiding collision between the torch 14 and the workpiece.

[others]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.
For example, the restoring force Fc may be a force that gradually increases as the tip of the torch 14 moves away from a predetermined reference position, and this reference position is not limited to the welding center plane C. Moreover, it is preferable that this reference position is configured to be changeable.
Specifically, the reference position may not be the center of the groove, but may be a position shifted left and right (in the X direction) from there. Alternatively, as shown in FIG. 9, the reference position (reference line) C1 may be set in which the torch 14 is swung left and right with respect to the welding direction. Thereby, weaving welding can be suitably performed.
Further, the reference position may be linear rather than planar as in the above embodiment. For example, when the reference position is a line along the Y direction, the Z direction position in addition to the X direction position becomes a parameter of the restoring force Fc.

Further, it is preferable that the outputs of the reaction force Fb and the restoring force Fc can be individually set to be turned on or off based on a user's operation or the like. Furthermore, it is preferable that the magnitudes of the outputs of the reaction force Fb and the restoring force Fc can be individually changed and adjusted based on user operations and the like.

Further, in the above embodiment, the object to be operated by the remote control device 3 is the welding vehicle 10, but the object to be operated by the remote control means according to the present invention is one having a working part that performs work on a workpiece. If so, there are no particular limitations. For example, it may be a stationary robot arm, a linear slider, an actuator, or the like.
Moreover, the remote control device 3 and the control device 4 may be configured integrally (for example, as an integrated remote control device).

Further, in the embodiment described above, welding work is performed by the work system 1. However, the work (type) according to the present invention is not limited to welding, and may be any work that can be performed on the workpiece by remotely controlling the work unit, and includes, for example, surface processing work such as polishing and painting.
In addition, the details shown in the above embodiments can be changed as appropriate without departing from the spirit of the invention.

1 Work system (remote control system)
3 Remote control device 4 Control device (force sense control means)
10 Welding vehicle 14 Torch 20 Plate material 20a Side surface 20b Top surface 21 Groove 25a Bottom surface 31 Remote control unit (remote control means)
41 CPU
C Welding center plane (reference position)
C1 Reference position (reference line)
Fb Reaction force Fc Restoring force F Resultant force Sc Collision avoidance surface Sw Work surface WK Operator

Claims (6)

a remote control means for remotely controlling a torch to perform welding work on a workpiece;
force sense control means for causing the remote control means to output a force according to the position of the torch;
Equipped with
The force sense control means causes the remote control means to output a first force that gradually increases as the tip of the torch moves away from a predetermined reference position.
Remote control system. The reference position is a welding center plane along the welding direction,
The remote control system according to claim 1. The force sense control means causes the remote control means to output, in addition to the first force, a second force that gradually increases as the tip of the torch approaches the workpiece.
The remote control system according to claim 1 or claim 2. The force sense control means is capable of individually setting output on/off switching of the first force and the second force.
The remote control system according to claim 3. The force sense control means is capable of individually changing the magnitude of the first force and the second force.
The remote control system according to claim 3 or claim 4. The force sense control means is configured to be able to change the reference position.
The remote control system according to any one of claims 1 to 5.

Images