JP7172466B2 - Tool center point setting method and setting device - Google Patents

Description

The present invention relates to a tool center point setting method and setting device.

Generally, when a robot performs various tasks, a tool center point (TCP), which is a reference point for controlling the robot, is set at the tip of the robot arm (the tip of the end effector).

In Patent Document 1 below, a jig having a jig coordinate system that is fixed at a fixed position from a TCP is fixed to an end effector, and when the TCP is displaced due to a collision or the like, the TCP is adjusted using the jig coordinate system. is disclosed.

Japanese Patent No. 4020994

By the way, when working with a robot in a dangerous place where people cannot enter, such as a disaster area, or in a special environment, it is often necessary to work on unknown objects, so TCP is set for unknown objects. It may be easier to do various tasks if you do. However, the conventional method assumes the use of an end effector with a jig coordinate system that does not change its positional relationship with the TCP. Can not do it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for setting a tool center point that can set a TCP on an unknown object.

One aspect of the present invention is a method for setting a tool center point (TCP) in a manipulator, wherein a virtual marker is superimposed on captured images captured by a plurality of imaging devices whose installation positions are known, and displayed on a display device. a display step of displaying on a display screen; and a processing device calculating a positional relationship between a known position of the manipulator and a position of the marker in the world coordinate system obtained based on the installation position of the marker. and a setting step of setting a position as the tool center point (TCP).

One aspect of the present invention is the above-described setting method, which includes an alignment step of aligning the position of the marker and the position to be set as the tool center point (TCP) on the display screen, wherein the setting step includes: , is performed after the registration step.

An aspect of the present invention is the above-described setting method, wherein in the setting step, the processing device sets a tool coordinate system based on the position of the tip of the manipulator and a marker coordinate system based on the position of the marker. The positional relationship is calculated by calculating a coordinate transformation matrix between and based on the position of the marker and the position of the tip of the manipulator in the world coordinate system.

An aspect of the present invention is the above-described setting method, wherein the setting step calculates a first coordinate transformation matrix for coordinate transformation from the world coordinate system to the tool coordinate system based on the position of the tip of the manipulator. a second computation step of computing a second coordinate transformation matrix for coordinate transformation from the world coordinate system to the marker coordinate system based on the position of the marker; and the first coordinate transformation and a third computing step of computing a third coordinate transformation matrix between the tool coordinate system and the marker coordinate system based on the matrix and the second coordinate transformation matrix.

One aspect of the present invention is a setting device for setting a tool center point (TCP) in a manipulator, comprising: a plurality of imaging devices whose installation positions are known; A display control unit that superimposes markers and displays them on a display screen of a display device, and calculates a positional relationship between a known position of the manipulator and a position of the marker in the world coordinate system obtained based on the installation position. a setting unit that sets the position of the marker as the tool center point (TCP) by doing so.

One aspect of the present invention is the setting device described above, which includes an operation unit that can arbitrarily change the position of the marker on the display screen.

As described above, according to the present invention, TCP can be set for an unknown object.

1 is a diagram showing an example of a schematic configuration of a robot system A to which a tool center point setting method according to an embodiment of the present invention is applied; FIG. It is a figure which shows an example of the display screen of the display apparatus 9 which concerns on one Embodiment of this invention. FIG. 4 is a diagram illustrating a TCP setting method according to an embodiment of the present invention; FIG. 4 is a diagram illustrating the flow of a TCP setting method according to an embodiment of the present invention; It is a figure explaining the effect which concerns on one Embodiment of this invention.

Hereinafter, a tool center point setting method and a tool center point setting device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of a schematic configuration of a robot system A to which a tool center point setting method according to an embodiment of the present invention is applied.

The robot system A is a system that includes a robot 1 and is capable of controlling the motion of the robot 1 to perform a predetermined work. Here, in this embodiment, the robot system A is a system capable of remotely controlling the robot 1 . That is, the robot system A is a system in which the operator can remotely control the operation of the robot 1 to perform a predetermined work.

For example, in the robot system A, the robot 1 is remotely controlled to grip a door knob to open the door or grip a tool in a dangerous place where people cannot enter, such as a disaster area, or in a special environment. It is possible to work with However, the robot system of the present invention is not limited to a system that remotely controls the robot 1 . Furthermore, as the prescribed work, the work of opening the door by grasping the knob of the door, the work of grasping the tool and processing the target object with the tool (cutting, grinding, etc.), welding, painting, finishing (deburring, Chamfering, rounding, polishing, etc.) and other work such as work.

Here, it is necessary to set a tool center point (hereinafter referred to as "TCP") as a reference point for controlling the robot 1, and control the robot 1 based on this TCP. Therefore, conventionally, a TCP is set at the tip of the end effector, and the operation of the robot 1 is controlled based on this TCP. However, in dangerous places where people cannot enter, such as disaster areas, or in special environments, it is better to set TCP to unknown objects instead of end effectors, as work is often performed on unknown objects. It can be easier to work. However, conventional methods can only set TCPs on known objects (eg, end effectors). Therefore, one of the features of the present invention is that it is possible to set a TCP for an unknown object in carrying out the above work.

An example of the configuration of the robot system A according to one embodiment of the present invention will be described below. FIG. 1 is a schematic configuration diagram of a robot system A according to one embodiment of the present invention.

A robot system A includes a robot 1 , a remote control device 2 , a robot control device 3 and a setting device 4 .

The robot 1 is, for example, a working robot, and can hold a door knob to open the door or hold a tool to work. The robot 1 is an example of the "manipulator" of the present invention.

The remote control device 2 can communicate with the robot control device 3 wirelessly or by wire. This remote control device 2 can be operated by an operator (user) and remotely controls the motion of the robot 1 via a robot control device 3 .

The robot control device 3 acquires a remote control command from the remote control device 2 by communicating with the remote control device 2 wirelessly or by wire. The robot control device 3 then controls the operation of the robot arm 5 based on the acquired remote control command, thereby moving the tip of the robot arm 5, that is, the processing tool 7, to a desired position. The robot control device 3 may be configured by a microprocessor such as a CPU or MPU, a microcontroller such as an MCU, or the like.

The setting device 4 is a device for setting TCP, which is a reference point for controlling the robot 1 .

A schematic configuration of the robot 1 according to one embodiment of the present invention will be described below.
The robot 1 comprises a robot arm 5 , a hand section 6 and a processing tool 7 .

The robot arm 5 has multiple articulated mechanisms. Each joint of the robot arm 5 is provided with a motor for driving each joint. The robot arm 5 can move, for example, in a three-dimensional space by driving the motor by the robot control device 3 . Each joint is provided with an encoder for detecting the rotation angle of the motor.

The hand unit 6 detachably connects the processing tool 7 to the robot arm 5 .

The processing tool 7 is an end effector attached to the tip of the robot arm 5 by the hand section 6 .
The processing tool 7 can move its position and orientation within a three-dimensional space by being driven by the robot arm 5 . In this embodiment, the processing tool 7 is a gripping part that grips an object, such as a gripper or a suction pad. However, the present invention is not so limited and the type of processing tool 7 is not particularly limited. For example, the processing tool 7 may be a tool changer for changing end effectors.

A force sensor that detects the external force F acting on the processing tool 7 may be attached between the three-dimensionally movable robot arm 5 and the processing tool 7 .

Next, a schematic configuration of the setting device 4 according to one embodiment of the present invention will be described.
A setting device 4 according to one embodiment of the present invention includes a plurality of imaging devices 8 , a display device 9 , an operation section 10 and a processing device 11 . Note that the display device 9 and the operation unit 10 may be configured integrally with the remote control device 2 . Further, in this embodiment, the setting device 4 has two imaging devices 8. However, the present invention is not limited to this. Well, if it is two or more, the number is not particularly limited. In addition, as the imaging device 8, for example, an imaging device that acquires a three-dimensional point group using a TOF (Time of Flight) camera or a laser sensor using reflection time and displays the measured values in three dimensions can also be used. In these cases, the functions of two or more imaging devices are substantially used in one device.

Each imaging device 8 is, for example, a stereo camera equipped with an imaging device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor) that converts condensed light into an electrical signal. However, each imaging device 8 is not limited to a stereo camera, and may be another camera capable of imaging a three-dimensional image such as a light field camera. The captured image of each imaging device 8 is transmitted to the processing device 11 in real time.

The position of each imaging device 8 in the three-dimensional world coordinate system is known and stored in the processing device 11 in advance. For example, this world coordinate system is set with the base on which the robot 1 is installed as a reference position. Therefore, the position of each imaging device 8, the position of the robot 1, and the positional relationship between each imaging device 8 and the robot 1 are known and may be stored in the processing device 11 in advance.

The display device 9 is a display device whose display is controlled by the processing device 11, and is a 3D monitor capable of stereoscopically displaying the captured images captured by the imaging devices 8 in this embodiment. For example, the display device 9 may be a display device such as a monitor for a personal computer, a display device of a mobile device such as a mobile phone, or a head mounted display.

The operation unit 10 can be operated by a user (for example, an operator) and is connected to the processing device 11 wirelessly or by wire. The operation unit 10 is operated when TCP is set, and transmits an operation signal to the processing device 11 when operated by a user.

A processing device 11 according to this embodiment includes a display control unit 12 and a TCP setting unit 13 . The processing device 11 may be configured by a microprocessor such as a CPU or MPU, a microcontroller such as an MCU, or the like.

The display control unit 12 stereoscopically displays each captured image captured by each imaging device 8 on the display screen of the display device 9, and superimposes a certain virtual marker BM on the captured image and displays it on the display screen. FIG. 2 is a diagram showing an example of the display screen of the display device 9 according to this embodiment.

As shown in FIG. 2, for example, the marker BM is a three-dimensional orthogonal coordinate system (hereinafter referred to as "marker coordinate system") _HM with the target point BP as the origin. The marker BM according to this embodiment is fixed and displayed at a predetermined position on the display screen of the display device 9 . This target point BP designates the position of the TCP. Therefore, in this embodiment, when the TCP is to be set at an arbitrary position of an unknown object (the grasped object shown in FIG. 2), the operator remotely controls the robot 1 to move the arbitrary position to the target point BP. need to align. The position of the target point BP in the three-dimensional world coordinate system (that is, the origin position of the marker coordinate system _HM ) is preset and stored in the TCP setting section 13 . For example, the position of the target point BP in the three-dimensional world coordinate system can be uniquely determined from the position (world coordinate system) of each imaging device 8 and the coordinate system of each imaging device 8. For example, TCP setting It may be calculated by the unit 13 . That is, since the position of each imaging device 8 in the world coordinate system is known, the TCP setting unit 13 can perform coordinate conversion between the coordinate system of each imaging device 8 and the world coordinate system. Therefore, the TCP setting unit 13 converts the position of the target point BP in the coordinate system of each imaging device 8 into the world coordinate system using the position of each imaging device 8 in the world coordinate system. It is possible to compute the position of the target point BP at .

When the TCP setting unit 13 acquires the operation signal from the operation unit 10, the tip position of the processing tool 7 in the three-dimensional world coordinate system (known and stored in advance in the processing device 11, for example) and the target By calculating the positional relationship with the position of the point BP, the position of the target point BP can be set in the TCP. For example, the tip position of the processing tool 7 can be uniquely obtained from each coordinate system fixed to each link of the robot arm 5 using the angle of each joint. may be computed.

A TCP setting method according to the present embodiment will be described below with reference to FIGS. 3 and 4. FIG. In the following description, a case where TCP is set to the tip of an unknown gripped object gripped by the processing tool 7 will be described as an example. However, the present invention is not limited to this, and TCP can also be set for known objects other than the grip.

First, the operator operates the remote control device 2 or the like to shift the robot system A to a TCP setting mode for setting TCP.

After shifting to the TCP setting mode, the processing device 11 acquires a captured image from each imaging device 8 at regular intervals. Then, the processing device 11 superimposes the marker BM indicating the marker coordinate system with the target point BP as the origin on the acquired captured image, and executes the display step of displaying the image on the display screen of the display device 9 ( step S101).

Next, the operator remotely controls the operation of the robot arm 5 via the remote control device 2 while confirming the display screen of the display device 9 (FIG. 3A), and on the display screen of the display device 9, , the tip of the gripped object for which TCP is to be set is aligned with the target point BP. Then, when the positioning of the tip of the gripped object with respect to the target point BP is completed, the operator operates the operation unit 10 (for example, presses down the operation unit 10) to confirm the above-described positioning (positioning step). . When operated by the operator, the operation unit 10 transmits an operation signal to the processing device 11 wirelessly or by wire.

When the TCP setting unit 13 acquires the operation signal (step S102), the position of the tip T of the processing tool 7, which is a known position in the robot 1, and the position of the marker BM obtained based on the installation position of each imaging device 8. The position of the marker BM (the position of the target point BP) is set as TCP by calculating the positional relationship with the position in the world coordinate system (the position of the target point BP) (step S103).

Specifically, as shown in FIG. 3B, when the TCP setting unit 13 acquires the operation signal, the TCP setting unit 13 sets the processing tool 7 in the world coordinate system stored in the storage unit (not shown) of the processing device 11. read the position of the tip T of the tip T, and convert the position of the tip T from the world coordinate system to the tool coordinate system _HT (for example, a homogeneous conversion matrix) _{TW → T} (first coordinate conversion matrix) Calculate. This tool coordinate system _HT is a three-dimensional orthogonal coordinate system based on the tip T of the processing tool 7 (first calculation step). In this first calculation step, the TCP setting unit 13 calculates the position of the tip T of the processing tool 7 in the world coordinate system from each coordinate system fixed to each link of the robot arm 5, and the angle of each joint. You may acquire by calculating using.

Further, upon acquiring the operation signal, the TCP setting unit 13 reads out the position of the target point BP in the world coordinate system, which is stored in the storage unit (not shown) of the processing device 11, and sets the position of the target point BP to the world coordinate system. A coordinate transformation matrix (for example, homogeneous transformation matrix) _TW→M (second coordinate transformation matrix) for transforming from the coordinate system to the marker coordinate system _HM is computed (second computation step). In this second calculation step, the TCP setting unit 13 may acquire the position of the target point BP in the world coordinate system by calculating from the installation position of the imaging device 8 or the like.

Then _{, the} TCP setting unit 13 uses a coordinate transformation matrix (for example _{, a} homogeneous transformation matrix ) T _T→M (third coordinate transformation matrix) is calculated (third calculation step). This coordinate conversion matrix TT _→M indicates the relative positional relationship between the position of the tip T of the processing tool 7 and the position of the target point BP. Therefore, the TCP setting unit 13 can set the position of the target point BP as TCP by obtaining the coordinate transformation matrix _TT→M .

Thus, the TCP setting unit 13 converts the coordinate transformation matrix _TT→M between the tool coordinate system _HT and the marker coordinate system _HM to the target point BP in the world coordinate system and the processing tool 7 in the world coordinate system. By calculating based on the position of the tip T, the position of the target point BP can be set as TCP. Therefore, it becomes possible to set the TCP for an unknown object. For example, by setting the TCP to the tip of the gripped object, it becomes possible to rotate the gripped object based on the tip by jogging, which improves operability. Improvement is expected.

Next, the effects of this embodiment will be described with reference to FIG.
For example, as shown in FIG. 5, consider a case where the robot 1 is remotely controlled and the processing tool 7 of the robot 1 grips the doorknob dn to open the door D. FIG. The door D can be opened and closed by rotating the hinge portion G as a center.
Here, when the TCP is set at the tip of the processing tool 7, the door D must be opened while combining the translational motion and the rotational motion around the point of the hand, and the work of opening the door D is very difficult. . However, if the TCP is set on the rotational axis R of the door D, the door D can be opened and closed only by rotational movement about the TCP, and the operation can be performed intuitively. Therefore, by using the TCP setting method according to the present embodiment, it is possible to set the TCP on the rotation axis R of the door D, which is an unknown object, and it is expected that work efficiency will be improved.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design and the like are included within the scope of the gist of the present invention.

(Modification 1) In the above-described embodiment, the TCP setting unit 13 calculates the coordinate transformation matrix _TT→M between the tool coordinate system _HT and the marker coordinate system _HM , so that the tip T of the processing tool 7 and the position of the marker BP in the world coordinate system (the position of the target point BP), but the present invention is not limited to this. It can be any known position on the manipulator.

(Modification 2) In the above embodiment, the position of the tip T of the processing tool 7 and the position of the marker BP in the world coordinate system (the position of the target point BP) are calculated by calculating the coordinate transformation matrix _TT→M. Although the relationship was computed, the invention is not so limited. That is, the present invention only needs to be able to calculate the positional relationship, and the calculation method is not particularly limited.

(Modification 3) In the above embodiment, the operator remotely controls the operation of the robot arm 5 and aligns the tip of the gripped object for which TCP is to be set with the target point BP on the display screen of the display device 9. However, the invention is not so limited. For example, on the display screen of the display device 9, the setting device 4 may be provided with a marker operation section capable of arbitrarily changing the position of the marker BP. By operating the marker operation unit, the operator moves the position of the target point BP, remotely controls the operation of the robot arm 5, and operates the marker operation unit to control the TCP. The position to be set may be aligned with the position of the target point BP. Note that this marker operating section may be configured integrally with the operating section 10 .

(Modification 4) In the above embodiment, the case where the setting positions of the imaging devices 8 are fixed has been described, but the present invention is not limited to this, and the setting device 4 adjusts the positions of the imaging devices 8. An adjuster may be provided. For example, the adjustment unit is operated by the operator, and the operator can operate the adjustment unit to capture an image from a desired position. However, if the setting device 4 has the adjusting unit, it is necessary to include a measuring unit that measures the position of each imaging device 8 in the world coordinate system after the position of each imaging device 8 is adjusted. Then, the measurement result of the measurement unit is transmitted to the processing device 11 by wire or wirelessly. Note that this adjustment section may be configured integrally with the operation section 10 .

As described above, in the method for setting the tool center point (TCP) in the robot 1 that is a manipulator, the processing device 11 adds a virtual a display step of superimposing such markers and displaying them on the display screen of the display device; and a setting step of setting the position of the marker BP as the tool center point (TCP) by calculating the positional relationship between the position of the marker BP and the position in the world coordinate system. is the setting method.

With such a configuration, a tool center point (TCP) can be set for an unknown object. Therefore, if a tool center point (TCP) is set at the tip of the gripped object, for example, it becomes possible to rotate the gripped object with reference to the tip by jogging, which is expected to improve operability.

The method of setting the tool center point (TCP) may include a positioning step of matching the position of the marker BP and the position to be set as the tool center point (TCP) on the display screen of the display device 9 . Then, the processing device 11 may perform the setting step after the alignment step.

According to such a configuration, an operator such as a pilot can intuitively and easily set the TCP while checking the display screen.

In the method of setting the tool center point (TCP), in the setting step, the processing device 11 establishes a tool coordinate system based on the position of the tip of the robot 1 and a marker coordinate system based on the position of the marker BP. A coordinate transformation matrix _TT→M may be calculated based on the position of the marker BP and the position of the tip of the robot 1 .

According to such a configuration, obtaining the coordinate transformation matrix _TT→M is equivalent to obtaining the positional relationship between the known position of the tip of the robot 1 and the position of the marker BP. A tool center point (TCP) can be set for the

A robot system 1 robot (manipulator)
2 Remote control device 3 Robot control device 4 Setting device 8 Imaging device 9 Display device 10 Operation unit 11 Processing unit 12 Display control unit 13 TCP setting unit (setting unit)

Claims (6)

A method for setting a tool center point (TCP) in a manipulator, comprising:
a display step of superimposing a virtual marker on an image captured by a plurality of imaging devices whose installation positions are known and displaying the image on a display screen of a display device;
A processing device determines the position of the marker as the tool center point (TCP) by calculating the positional relationship between the known position of the manipulator and the position of the marker in the world coordinate system obtained based on the installation position. a configuration step that sets as
A method for setting a tool center point (TCP), comprising: an alignment step of aligning the position of the marker and the position to be set as the tool center point (TCP) on the display screen;
2. The method of setting a tool center point (TCP) according to claim 1, wherein said setting step is performed after said alignment step. In the setting step, the processing device converts the coordinate transformation matrix between the tool coordinate system based on the position of the tip of the manipulator and the marker coordinate system based on the position of the marker to the world coordinate system. 3. The tool center point (TCP) setting method according to claim 1, wherein the positional relationship is calculated by calculating based on the position of the marker and the position of the tip of the manipulator. The setting step includes:
a first computing step of computing a first coordinate transformation matrix for coordinate transformation from the world coordinate system to the tool coordinate system based on the position of the tip of the manipulator;
a second calculation step of calculating a second coordinate transformation matrix for coordinate transformation from the world coordinate system to the marker coordinate system based on the position of the marker;
a third computing step of computing a third coordinate transformation matrix between the tool coordinate system and the marker coordinate system based on the first coordinate transformation matrix and the second coordinate transformation matrix;
The tool center point (TCP) setting method according to claim 3, characterized by comprising: A setting device for setting a tool center point (TCP) in a manipulator,
a plurality of imaging devices whose installation positions are known;
a display control unit that superimposes a virtual marker on the captured image captured by each of the imaging devices and displays it on the display screen of the display device;
The position of the marker is set as the tool center point (TCP) by calculating the positional relationship between the known position of the manipulator and the position of the marker in the world coordinate system obtained based on the installation position. a setting unit;
A setting device comprising: 6. The setting device according to claim 5, further comprising an operation unit capable of arbitrarily changing the position of the marker on the display screen.

Images