JP2002292582A - Working robot device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a work robot device capable of easily performing a work when a robot coordinate system is different from a work coordinate system to be worked. An operation in which a robot main body having a tool unit for performing a predetermined operation on an operation target member attached to an end of an arm unit is operated on an operation panel via a control unit. The robot device 1 includes a work object detection unit 14 for detecting the shape of the work target member via the distance sensor 8 and a work coordinate system (cylindrical coordinate system) corresponding to the shape of the work target member. The control parameter values (r, θ, L, α, β, γ) are controlled on a robot coordinate system (orthogonal coordinate system) that determines the position and orientation of the tool unit 7 as viewed from the robot body 4. Parameter values (X, Y, Z,
a, b, c) is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working robot device.

[0002]

2. Description of the Related Art In recent years, robot apparatuses have been used for many tasks. Since this type of robot apparatus is specialized for each task, parameters for operating the robot, that is, driving coordinates for driving the robot, are used. The system is usually
A rectangular coordinate system is used. For example, a robot device for inspecting an inner wall surface of a road tunnel or the like is mounted on a work vehicle, and a work tool unit provided at a tip of a robot arm is based on XYZ coordinates. Being driven.

[0003]

As described above, the coordinate system for driving the inspection tool in the inspection robot apparatus is an orthogonal coordinate system, whereas the inner wall surface of the tunnel to be operated is a cylinder. There is a problem that it is difficult for the operator to work the inspection tool along the inner wall surface of the tunnel because of the surface.

Accordingly, an object of the present invention is to provide a work robot apparatus which can easily perform a work when the robot coordinate system is different from the work coordinate system to be worked.

[0005]

According to a first aspect of the present invention, there is provided a working robot apparatus according to the first aspect of the present invention, wherein a tool for performing a predetermined work on a work target portion is attached to a tip of an arm. A robot main body, which is operated by an operation panel via a control device, wherein the control device has control parameter values on a work coordinate system corresponding to the shape of a work target part. Is converted into a control parameter value on a robot coordinate system that determines the position and orientation of the tool unit as viewed from the robot body.

According to a second aspect of the present invention, there is provided a working robot apparatus, wherein the control device in the robot apparatus according to the first aspect includes a distance sensor provided at a tip end of an arm portion at a plurality of working target parts. After measuring the distances to the planes and obtaining a plurality of local plane equations based on the measured distances, the least squares method is applied to the equations of each plane to determine the coefficients of the plane equations. In this way, there is provided a work target part detecting means for obtaining the surface shape of the work target part.

Further, a working robot device according to a third aspect of the present invention is the working robot device according to the first or second aspect, wherein the working coordinate system is a cylindrical coordinate system and the robot coordinate system is a rectangular coordinate system. It is.

According to the configuration of the working robot device,
Since the control device for controlling the robot body is provided with parameter conversion means for converting a control parameter value on the work coordinate system according to the shape of the work target part into a control parameter value on the robot coordinate system, Even when the coordinate system is different from the robot coordinate system, the work can be easily performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A working robot apparatus according to an embodiment of the present invention will be described below with reference to FIGS.

A working robot device according to the present embodiment will be described as a robot device for inspecting, for example, the presence or absence of a scratch on the inner wall surface of a tunnel on an automobile road.

That is, as shown in FIGS. 1 and 2,
The working robot device 1 includes a robot body 4 disposed on a traveling body that can travel in the tunnel 2, for example, a traveling vehicle 3, a control device 5 for controlling the robot body 4, and the control device 4. And an operation panel 6 for operating the robot. The robot body 4 includes, for example, a base robot unit and an articulated (puma-type) arm robot unit supported by the base robot unit, and is driven by the base robot unit. Although the working range is expanded and control is facilitated, the arm robot unit will be described below as the robot main body 4. Of course, an end effector provided at the tip of the arm robot unit (hereinafter referred to as a tool unit)
An inspection tool is attached to 7 as a work tool.

By the way, the gist of the present invention is to facilitate work such as inspection in a working robot apparatus, that is, to change a driving coordinate system (hereinafter also referred to as a robot coordinate system) {R} in the robot body 4 into a work target member ( The operation is performed in the work coordinate system {L} corresponding to the tunnel inner wall surface 2a which is the work target part). Therefore, in the present embodiment, the robot body 4 is controlled in the rectangular coordinate system. Since the work target member is the semi-cylindrical tunnel inner wall surface 2a, a case where a cylindrical coordinate system is used as the work coordinate system will be described.

As shown in FIG. 3, an orthogonal coordinate system (X, Y, Z) is used as a robot coordinate system {R} which is a drive coordinate system of the robot body 4, and for example, the X axis is a tunnel axis. In the direction along f, the Y axis is set in the horizontal direction orthogonal to the tunnel axis f, and the Z axis is set in the height direction.

[0014] On the other hand, a cylindrical coordinate system is a task coordinate system {L} (r, θ, y) but is used, y-axis is coincident to the tunnel axis f, theta is as y-axis the origin O _L The angle of inclination in an orthogonal vertical plane and from the vertical axis (also the Z axis), r
Represents the radial distance from the origin O _L.

Here, a control device 5 for controlling the robot body 4 and an operation panel 6 for instructing the control device 5 to issue an operation command and the like, and a robot from the work coordinate system {L} performed by the control device 5 The procedure for converting the control parameters into the coordinate system {R} will be described.

First, as shown in FIG.
Input means for inputting and instructing an operation command relating to the position and orientation of the tool unit 7 of the robot body 4, for example, an input key 6 a is provided, and a conversion mode and coordinates for converting a coordinate system for controlling the robot body 4. A mode switching switch 6b is provided as mode switching means for switching between a non-conversion mode in which conversion is not performed and a measurement mode for detecting a work target member.

The control device 5 receives an operation command from the operation panel 6 in the conversion mode of the mode changeover switch 6b to convert the control parameters of the working coordinate system {L} into the control parameters of the robot coordinate system {R}. A parameter conversion unit (an example of a parameter conversion unit, specifically formed of a coordinate conversion program), a control parameter in the robot coordinate system converted by the parameter conversion unit 11, and the mode changeover switch In the non-conversion mode 6b, a robot reverse conversion unit 12 for directly inputting an operation command from the operation panel 6 to calculate drive parameters (θ _{1 to} θ ₆ ) of the robot body 4, and a calculation by the robot reverse conversion unit 12 A drive control unit 13 for controlling the robot main body 4 based on the set driving parameters, and an arm 4a of the robot main body 4
A work object detection unit (an example of work object part detection means) which inputs a measurement signal from a distance sensor 8 provided on a tool unit 7 attached to the tip of the work and detects the shape of the tunnel inner wall surface 2a as a work object member. (Specifically, it is constituted by a program, the contents of which will be described later.)
Are provided.

Since the robot main body 4 is normally moved from the tunnel axis f toward the inspection wall surface, that is, at a position close to the tunnel inner wall surface 2a, in the conversion procedure of this description, as shown in FIG. , The working coordinate system {L} is once transformed into an intermediate coordinate system {C} using the same orthogonal coordinate system as the robot coordinate system at the center position of the tunnel 2, and then the intermediate coordinate system {C} is tunneled. Is converted to a robot coordinate system {R} separated by a predetermined distance W from the center position of the robot. Of course, the origin O _C of the intermediate coordinate system {C} is the intersection of the X-Z plane and the tunnel axis f of the robot coordinate system {R}. In FIG. 3, in order to make the intermediate coordinate system {C} and the working coordinate system {L} easy to understand, the origins O _{C of} both of them are shown.
They are drawn offset from each other to each other to and O _L. Also,
As shown in FIG. 1, the height in the Z-axis direction of the origin O _R of the robot coordinate system {R} has been slightly higher with respect to the origin O _C of the intermediate coordinate system {C}, the following description In the following, a description will be given assuming that the heights are the same (of course, the height is actually considered).

The procedure for converting the control parameters will be described below. First, in the measurement mode, the shape of the inner wall surface of the tunnel, that is, the tool coordinate system {T}, which is the coordinate system of the workpiece, is measured by a distance sensor (also called a displacement sensor). Specifically, a laser beam or an ultrasonic wave is used). In addition, the cylindrical coordinate system is used to represent the position of the working coordinate system {L}, and the radius of the tool part {T} is set to the reference axis (Z axis) in order to simplify the expression. It is represented by the coincident Euler angles (α, β, γ).

In this embodiment, the Euler angles are α, β, and γ in the order of Z-axis-Y-axis.
(Rad) is used. Thus, the reference axis of the Euler angle is set to the origin O of the tool part {T}.
Since the position of the tool coordinate system {T} is changed for each angle θ of the radius r because the vector is set to coincide with the vector indicating _R (radius r direction), the instantaneous coordinate system {U} Also called.

As shown in FIG. 4, first, at least three or more measurement points during one rotation of the arm 4a to which the distance sensor 8 is attached, for example, at the tunnel inner wall 2a.
Until seek distance d to the origin O _R of the distance the robot coordinate system on the basis of 'the distance d with measuring the' d {R} of, and (a curved surface) in the tunnel wall in the measurement point by using the distance d Is approximately detected as a plane using the least squares method.

Here, a method of obtaining the above-mentioned approximate plane by the least square method will be described. First, the arm unit 4a of the robot body 4 is rotated once around its axis by the distance sensor 8 attached to the tool unit 7, and at least 3
In areas more points to determine the distance d of the working robot apparatus 1 of the origin i.e. robot coordinate system from the origin O _R of {R} to the tunnel inner wall surface 2a.

Each distance d obtained by this measurement is substituted into the following equation (1), and equations are created by the number of measurement points. lx + my + nz = d (1) where l, m and n represent the direction cosine to the plane.

For ease of calculation, a description will be given based on the following equation (2) obtained by dividing (normalized) equation (1) by d. ax + by + cz = 1 (2) Here, the position of the measurement point measured by the distance sensor 8 is represented by S _{i.
(X i, y i, z} i) When the error delta _i in (2)
Is represented by the following equation (3).

Δ _i = ax _i + by _i + cz _i −1 (3) where i in the equation (3) represents a measurement point, and 1 <
i ≦ n (where n is the number of measurement points and n ≧ 3 in order to obtain an approximate expression of a plane).

The least-squares method obtains an optimal approximate solution by minimizing the sum of squares of the equation (3). Naturally, if the number of measurement points is increased, a highly accurate plane equation can be obtained. .

The sum of squares of the error at each measurement point is expressed by the following equation (4).

[0028]

(Equation 1) The necessary conditions of a, b, and c that minimize the above equation (4) are expressed by the following equation (5).

[0029]

(Equation 2) From the above equations (4) and (5), a ternary simultaneous equation shown in the following equation (6) is obtained.

[0030]

(Equation 3) By solving the simultaneous equations of the above equation (6), a plane equation is obtained.

Therefore, the shape of the inner wall surface 2a of the tunnel to be worked can be detected, whereby the basic posture (the posture of the tool frame {T}) to be taken by the tool unit 7 can be known.

That is, if the equation of the wall surface (inner wall surface) is obtained, the normal vector on the wall surface is obtained. At this time, the normal vector is set to the X axis (in this embodiment, the X axis of the tool frame is set to the front direction of the inspection tool), and the other axes (Y axis,
A coordinate system appropriately arranged so as to form a right-handed system on the plane on which the (Z axis) is obtained is defined as a wall surface frame. If the target value of the tool frame (inspection tool itself) at this time is defined on the wall surface frame, relative positioning with respect to the wall surface becomes easy. For example, if the target value of the tool frame in the wall frame is (−10, 0, 0, 0, 0, 0),
The inspection tool is perpendicular to the wall surface and is located 10 mm before.

Hereinafter, the basic posture of the tool unit 7 at each work position is referred to as an instantaneous coordinate system {U}. Next, a procedure for converting the operation data based on the work coordinate system {L} input from the operation panel 6 into a drive command for the robot body 4 driven by the robot coordinate system {R}, that is, a parameter in the conversion mode The conversion procedure in the conversion unit 11 will be described.

In the parameter conversion unit 11, as described above, the working coordinate system {L}, which is a cylindrical coordinate system, is temporarily converted to an intermediate coordinate system {C}, which is an orthogonal coordinate system located on the center of the cylinder. After that, the intermediate coordinate system {C} is converted into a robot coordinate system {R} which is a rectangular coordinate system.

First, a procedure for converting the working coordinate system {L}, which is a cylindrical coordinate system, to the intermediate coordinate system {C}, which is a rectangular coordinate system, will be described with reference to FIGS. FIG.
Indicates the relationship between the coordinate axes in the working coordinate system {L}, which is a cylindrical coordinate system, and the coordinate axes in the intermediate coordinate system {C}, which is a rectangular coordinate system.

A point P ^L (r ^L , θ ^L , y ^L ) indicating the origin position of the tool section 7 in the work coordinate system {L} (note that the right shoulder of each parameter shown in the text of this specification) The symbol is originally attached to the left shoulder as shown in the mathematical formula of the specification. It is only attached to the right shoulder due to data recording restrictions.) The coordinate conversion to the point P ^C (X ^C , Y ^C , Z ^C ) is performed based on the following equation (7).

[0037]

(Equation 4) Then, a point P ^R (X ^R , Y ^R , Z) on the robot coordinate system {R} from a point P ^C (r ^C , θ ^C , y ^C ) indicating the position of the tool unit 7 in the intermediate coordinate system {C}. ^R ) is represented by the following equation (8).

[0038]

(Equation 5) However, (8) where homogeneous transformation matrix T ^R _C showing the relationship between the robot coordinate system {R} intermediate coordinate system {C} is known,
It is required in advance.

Next, the posture conversion of the tool unit 7 will be described. Generally, Euler angles are used for the posture of the robot coordinate system based on the rectangular coordinate system, and in the working coordinate system (cylindrical coordinate system) {L} according to the present embodiment, as described above, Euler angles shall be used.
Therefore, first, it is necessary to determine the reference rotation axis. In the present embodiment, the Euler angle is defined based on the normal vector of the cylindrical surface that is the tunnel inner wall surface 2a. By defining in this way, even when the tool section 7 is moved to an arbitrary position, the relative attitude relationship with the tunnel inner wall surface 2a does not change, so that the operation can be easily performed.

Hereinafter, the posture of the tool unit 7, which is the posture of the tip arm 4a of the robot body 4, will be described with reference to FIG. The posture (rotation matrix) of the tool coordinate system {T} (coordinate system whose origin is TCP) in the working coordinate system {L} can be represented using an instantaneous coordinate system {U}.

That is, the rotation matrix R ^R _T for the posture (transformation) of the tool coordinate system {T} from the working coordinate system {L} to the robot coordinate system {R} is represented by the tool coordinate system in the instantaneous coordinate system {U}. Rotation matrix R ^U _T to {T}, intermediate coordinate system {C}
With the rotation matrix R ^R _C to the intermediate coordinate system {C} in the rotation matrix R ^C _U to the instantaneous coordinate system {U}, and the robot coordinate system {R}, is expressed as follows (9) You.

[0042]

(Equation 6) For the rotation matrix R ^U _T, Euler angles is a parameter representing the angular specified in the work coordinate system {L} (α,
β, γ) itself.

Incidentally, the rotation matrix R ^U _T, Specifically demonstrated using Euler angles, is as follows. Rotation matrix R
Is defined as the following equation (10):

[0044]

(Equation 7) The Euler angles (α, β, γ) are represented by the following equation (11).

[0045]

(Equation 8) Therefore, the rotation matrix R is calculated as Euler angles (α, β, γ)
When expressed by the following equation (12) is obtained.

[0046]

(Equation 9) As for the rotation matrix R ^C _U, it is expressed as follows.

That is, the unit vector of each coordinate axis in the instantaneous coordinate system {U} with the normal vector to the tunnel inner wall surface 2a at a certain position viewed from the intermediate coordinate system {C} as the reference axis is given by the following equation (13). Is represented by

[0048]

(Equation 10) Thus, from the intermediate coordinate system {C} to the instantaneous reference coordinate system {U}
The rotation matrix R ^C _U to is expressed by the following equation (14).

[0049]

[Equation 11] As for the rotation matrix R ^R _C, as described in the first part, for simultaneous conversion matrix T ^R _C is known, the rotation matrix R ^R _C is also known.

Thus, each of the rotation matrices R ^U _T , R ^C _U , R ^R _C
Thus, the posture in the work coordinate system {L} can be converted into the posture in the robot coordinate system {R}. As described above, the vector P ^L (r, θ, y, α, β, γ) representing the position and orientation in the cylindrical coordinate system {L} is a vector representing the position and orientation in the robot coordinate system {R}. P ^R (X,
Y, Z, a, b, c).

That is, the operator operates the operation panel 6 to set predetermined parameters, that is, the position y in the tunnel axis direction,
When the inclination angle θ from the vertical axis and the radial distance r from the tunnel axis are input, the parameter conversion unit 11 converts the data into the coordinate data of the intermediate coordinate system {C}, and then immediately converts the robot coordinate system { It is converted into coordinate data on R #.

Then, based on the coordinate data, the rotation angle θ of each arm is calculated by the robot inverse transform unit 12, and the tool unit 7 is moved to a predetermined position. Hereinafter, a brief operation of the working robot device will be briefly described.

At the start of the operation, first, the tunnel center f
And set between, ie the transformation matrix T ^R _C between the robot coordinate system {R} intermediate coordinate system {C} with the robot body 4. Next, an operation command is input as a numerical value from the operation panel 6 using the input keys 6a.

Then, after the coordinates in the work coordinate system {L} are calculated, the coordinates are converted into the robot coordinate system {R} via the intermediate coordinate system {C}. Then, based on the obtained coordinate values, a robot inverse transformation is performed, and rotation angles θ _{1 to} θ ₆ on the respective robot axes are obtained and output to the respective driving servomotors. This conversion loop has a short period (for example, 10 m
(s cycle).

[0055] In the above description, when the transformation matrix T ^R _C of the robot coordinate system {R} intermediate coordinate system to the {C} has been described as being known in advance, not known, work By using the method of detecting the surface shape of the target member and determining the center coordinates of the intermediate coordinate system {C},
We are determined the homogeneous transformation matrix T ^R _C. For example, when obtaining the center axis of the tunnel, the approximate plane is detected at a plurality of locations, the normal vectors of the plurality of planes are obtained, and the intersection of the plurality of normal vectors is obtained. The position of the axis can be determined.

As described above, the control device 5 for controlling the robot body 4 detects the shape of the work object, for example, the shape of the inner wall surface 2a of the tunnel using the distance sensor 8 attached to the tool portion 7. A work object detection unit 14 to be obtained and a parameter conversion unit 11 for converting an operation command from the work coordinate system {L} to a robot coordinate system {R} using the shape data detected by the work object detection unit 14 are provided. Therefore, the workability of the robot can be improved.

When the control of the robot body is performed using the rectangular coordinate system, the mode changeover switch 6b is used to set the non-conversion mode, and the operation key is directly input to the rectangular coordinate system {R} from the input key 6a. Should be input.

By the way, in the above-described embodiment, the case where the present invention is applied to the robot apparatus for inspecting the inner wall surface of the tunnel has been described. However, the present invention is not limited to such a work. The present invention can be applied to any work as long as the coordinate system advantageous for the work is different.

In the above embodiment, the conversion between the rectangular coordinate system and the cylindrical coordinate system has been described.
In addition, the present invention can be applied to conversion between an orthogonal coordinate system and a spherical coordinate system or between a cylindrical coordinate system and a spherical coordinate system.

[0060]

As described above, according to the configuration of the working robot apparatus of the present invention, the control device for controlling the robot main body transmits the control parameter values on the working coordinate system corresponding to the shape of the work target part to the robot. Since a parameter conversion means for converting into a control parameter value on the coordinate system is provided, even when the work target coordinate system is a coordinate system different from the robot coordinate system, the work can be easily performed.

Further, since the control device for controlling the robot main body is provided with work target part detection means capable of detecting the surface shape of the work target part using the distance sensor, the work target part can be automatically detected. Therefore, workability can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic front view showing a working state of a working robot device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of the working robot device.

FIG. 3 is a perspective view for explaining coordinate conversion in the working robot device.

FIG. 4 is a main part side view for explaining coordinate conversion in the working robot device.

FIG. 5 is a schematic diagram for explaining coordinate conversion in the working robot device.

FIG. 6 is a schematic diagram for explaining coordinate conversion in the working robot device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Working robot device 2 Tunnel 2a Tunnel inner wall surface 3 Running vehicle 4 Robot main body 5 Control device 6 Operation panel 6b Mode switch 7 Tool unit 8 Distance sensor 11 Parameter conversion unit 12 Robot reverse conversion unit 13 Drive control unit 14 Work target detection Department

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kunio Miyawaki 1-7-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka Inside Hitachi Zosen Corporation (72) Inventor Shosuke Kawachi 1 Minami-Kohoku, Suminoe-ku, Osaka-shi, Osaka No. 7-89 F-term in Hitachi Zosen Corporation (reference) QQ09

Claims (3)

[Claims] 1. A work robot apparatus in which a tool body for performing a predetermined work on a work target part is attached to a tip end of an arm part via a control device via an operation panel. In the control device, the control parameter value on the work coordinate system according to the shape of the work target part, the control parameter on the robot coordinate system to determine the position and orientation of the tool unit viewed from the robot body A work robot device comprising a parameter conversion means for converting a value into a value. The control device measures distances to a work target site at a plurality of positions by using a distance sensor provided at a tip of an arm portion, and calculates a local plane equation at the work target site based on the measured distances. After obtaining several
2. A work target part detection means for obtaining a surface shape of a work target part by determining a coefficient of a plane equation by applying a least square method to each of the plane equations. Work robot device. 3. The working robot device according to claim 1, wherein the working coordinate system is a cylindrical coordinate system, and the robot coordinate system is a rectangular coordinate system.