JPH08118277A - Force control robot - Google Patents

Abstract

PURPOSE: To obviate the necessity of changing the designation of the pushing direction of an end effector from the first to the last of the work, even in the work in which changing the pushing direction of the defector according to the shape of a working objective substance is necessary during the work, such as in the polishing work for a curved surface or in the chamfering work for the uneven end part of the periphery of the work objective substance. CONSTITUTION: A force control robot for shifting an end effector along the surface 15 of a working objective substance W1, carrying out control so that the end effector 5 is pushed onto the surface 15 by a target pushing force is equipped with a direction setting means 10 which sets the pushing direction for the end effector 5 in a prescribed pushing direction which is prescribed according to the selected direction N1 which is selected in the desired direction in the operation space and the shift direction V1 of the end effector 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force control robot,
In particular, the present invention relates to a force control robot that moves an end effector along a surface of a work object while controlling the end effector to press the surface of the work object with a target pressing force.

[0002]

2. Description of the Related Art A force control robot controls an end effector so that the end effector is pressed against a surface of a work target with a target pressing force, and moves the end effector along the surface of the work target to perform work.

As a method of designating the direction and magnitude of the target pushing force in the force control robot, a method of directly designating the magnitude and direction of the target pushing force within the force control program is mainly used. For example, the magnitude of the pressing force is specified by numerical values such as 2.0 kgf and 3.0 kgf, and the pressing direction is fixed on the world coordinate system, the robot base coordinate system fixed to the robot base, or the work target work. It is designated by the coordinate system and the coordinate axis direction such as the X + direction or the Y- direction of the Cartesian coordinate system in the created work coordinate system.

These methods of designating the magnitude and direction of the target pressing force are convenient when the pressing direction of the end effector does not change from the beginning to the end of the work, such as polishing work on a flat surface.

[0005]

However, such as polishing work of a curved surface or chamfering of an uneven end portion around the work object, the end effector is pressed according to the shape change of the work object during the work. In the case of a work in which the direction needs to be changed, it is necessary to change the designation of the pressing direction of the end effector according to the shape change of the work target.
Therefore, there is a problem that the generation of the operation program of the force control robot is very complicated.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to perform work such as polishing of a curved surface or chamfering of an edge portion having irregularities around the work object during work. It is an object of the present invention to provide a force control robot that can easily specify the pressing direction of the end effector even in the case where the pressing direction of the end effector needs to be changed according to the shape change.

[0007]

In order to achieve the above object, the force control robot according to the present invention controls the end effector so that the end effector is pressed against the surface of a work object with a target pressing force. A force control robot for moving an end effector, comprising direction setting means for setting a pressing direction of the end effector to a predetermined pressing direction defined by a selection direction desired in a work space and a moving direction of the end effector. It is characterized by

Preferably, the predetermined pressing direction is a direction orthogonal to the selecting direction and the moving direction of the end effector.

Also, preferably, the selection direction is a surface normal direction of the work object.

[0010]

In consideration of the shape characteristics of the work object and the characteristics of the work performed on the work object, a suitable selection direction is selected for the work space. For example, the surface normal direction of the work target is selected as the selection direction. The end effector moves along the surface of the work object according to the operation program. The moving direction of the end effector can be known from the position coordinate data of the end effector or the data about the moving direction described in the operation program. The predetermined pressing direction in which the end effector presses the surface of the work target is a direction defined by the selected selection direction and the moving direction of the end effector, for example, a direction orthogonal to both directions.

Once the selection direction is specified, the direction in which the end effector is pressed against the surface of the work object can be automatically specified in a fixed relationship with the moving direction of the end effector.

As a result, it is necessary to change the pressing direction of the end effector according to the shape of the work object during the work, such as the work of polishing a curved surface or the chamfering work of the irregular end portion around the work object. Even in the case of a certain work, it is not necessary to change the designation of the pressing direction of the end effector from the beginning to the end of the work, and the operation program can be generated very easily.

[0013]

Embodiments of the force control robot according to the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of the force control robot of this embodiment. In FIG. 1, the force control robot includes a robot body 1, a controller 2 of the robot body 1, and an operation pendant 3. The robot body 1 is a 6-axis cylindrical coordinate type robot, and a 6-axis force sensor 4 and a disc grinder as an end effector 5 are provided at the hand of the robot body 1.
The end effector 5 uses the target pressing force to work the work W.
Work is performed by moving along this surface while controlling the force so as to press it against the surface.

The controller 2 includes an end effector 5
The direction setting means 10 for setting the direction in which the work object W is pressed as the predetermined pressing direction is provided. The direction setting means 10 includes data for specifying the selection direction input from the operation pendant 3, and the end effector 5.
The predetermined pressing direction is calculated when the end effector 5 moves by referring to the data regarding the moving direction obtained from the position coordinate data of 1. As the data regarding the moving direction of the end effector 5, the data regarding the moving direction of the end effector 5 described in the operation program based on the work plan may be referred to.

Referring to FIGS. 2 and 3, the first aspect of the present invention is described.
An example will be described. The robot body 1 includes a cylindrical rotary grinder as the end effector 5. The work object W1 includes a curved surface 15 having a wavy undulation in the longitudinal direction and a flat surface 1 parallel to each other in the lateral direction.
6 and 17. Further, the normal direction of the curved surface 15 and the normal direction of the flat surface 16 are orthogonal to each other. The cylindrical side surface of the end effector 5 is force-controlled so as to be pressed against the curved surface 15 with the target pressing force, and is moved in the direction of the moving direction vector V1 shown in FIG. 2 to perform the polishing work.

In this embodiment, the selected direction in the working space is the direction of the surface normal direction vector N1 of the flat surface 16. The direction of the surface normal direction vector N1 is the flat surface 1
Since 6 is a plane, it is a constant direction regardless of the moving direction of the end effector 5. The direction selecting means 10 sets the predetermined pressing direction of the end effector 5 to the direction of the pressing direction vector F1 represented by the equation (1). The pressing direction vector F1 is given by F1 = V1 × N1 (1) as an outer product of the vector V1 and the vector N1.

FIG. 3 is a view of the flat surface 16 looking toward the surface normal direction vector N1. The pressing direction vector F1 at each position A, B, C when the end effector 5 moves at each position A, B, C on the curved surface 15 is shown. In FIG. 3, even when the end effector 5 moves on the curved surface 15 having a wavy undulation, the movement direction vector V1 is always in the direction along the curved plane by force control or a pre-created operation program. Since it is set, as a result, at each position A, B, C, it is recognized that the position is always pressed toward the direction close to the normal line direction of the curved surface 15.

As described above, according to the configuration of this embodiment, since the direction setting means 10 is provided, the pressing direction of the end effector 5 can be changed according to the surface shape of the curved surface 15 of the work W1 during the work. In the polishing work that needs to be changed, the end effector 5 is used from the beginning to the end of the work.
It is not necessary to change the designation of the pressing direction of, and the operation program can be generated very easily.

Next, a second embodiment of the present invention will be described with reference to FIGS. The robot body 1 includes a conical cutter as the end effector 5. The work object W2 has a flat surface 18 and a curved surface 19, and a work end 20 is formed as a line of intersection between the flat surface 18 and the curved surface 19. The workpiece end 20 forms a coplanar curve. Also, the normal direction of the flat surface 18 and the curved surface 1
It has a relationship orthogonal to the normal direction of 9. The conical surface of the conical cutter 5 is force-controlled so as to be pressed to the work end 20 with a target pressing force, and the moving direction vector V2
And the chamfering work of the work end portion 20 is performed.

In this embodiment, the selected direction in the working space is the direction of the surface normal direction vector N2 of the flat surface 18. The direction selecting means 10 sets the predetermined pressing direction of the end effector 5 to the direction of the pressing direction vector F2 represented by the equation (2). Pressing direction vector F
2 is given by F2 = V2 × N2 (2) as an outer product of the vector V2 and the vector N2.

FIG. 5 is a view of the flat surface 18 looking toward the surface normal vector N2. The pressing direction vector F2 at each position A, B, C when the end effector 5 moves each position A, B, C on the work end 20 is shown. In FIG. 5, the end effector 5 is
Even when moving on the curved work end 20,
Since the movement direction vector V2 is always set in the direction along the curved work end portion by the force control or the operation program created in advance, as a result, each position A,
It is recognized that B and C are always pressed in the direction normal to the curved surface 19.

As described above, according to the configuration of this embodiment, since the direction setting means 10 is provided, the pressing direction of the end effector 5 according to the curved shape of the work end 20 of the work W2 during work. In the chamfering work that needs to be changed, it is not necessary to change the designation of the pressing direction of the end effector 5 from the beginning to the end of the work, and the operation program can be generated very easily.

In the above description of the embodiment, the case where the selection direction is the surface normal direction of the work object has been described as an example, but the present invention is not limited to this, and the selection direction is the end effector 5. It suffices to be fixed regardless of the moving direction, and may be appropriately selected according to the shape of the work object. Further, although the selection direction is shown as an example in which the direction is orthogonal to the moving direction of the end effector 5, the selection direction is not necessarily limited to this, and may be selected according to the shape of the work target.

Also, an example has been shown in which the predetermined pressing direction is a direction orthogonal to both the selection direction and the movement direction of the end effector 5, but the present invention is not limited to this, and the selection direction and the movement direction of the end effector 5 are not limited to this. Depending on the shape of the work object, it is possible to set the direction at an angle other than 90 degrees with respect to the plane to be determined.

Further, the axis configuration of the robot body 1 does not have to be a 6-axis cylindrical coordinate type, and may be any configuration such as an articulated type, a polar coordinate type or a rectangular coordinate type. Further, the force sensor of the hand portion is not limited to the 6-axis force sensor 4 and may have another configuration as long as it can detect the force acting on the end effector 5.

[0026]

As described above, according to the structure of the present invention, since the direction setting means is provided, it is possible to perform the polishing work on a curved surface or the chamfering work on the uneven end around the work object. Even when the work requires changing the pushing direction of the end effector according to the shape of the work object during work, it is not necessary to change the designation of the pushing direction of the end effector from the beginning to the end of the work. The generation can be done very easily.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of an embodiment of a force control robot according to the present invention.

FIG. 2 is a diagram for explaining a polishing operation for a curved surface in the first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a relationship among a movement direction vector V1 of an end effector, a selection direction vector N1 selected in a work space, and a pressing direction vector F1 in the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a chamfering work of a work end portion according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a relationship between a traveling direction V2 of the end effector, a selection direction vector N2 selected in the work space, and a pressing direction vector F2 in the second embodiment of the present invention.

[Explanation of symbols]

1 Robot Main Body 4 6-axis Force Sensor 5 End Effector (Rotary Grinder, Cone Cutter) 10 Direction Setting Means W, W1, W2 Work Object 15, 19 Curved Surface 16, 17, 18 Flat Surface 20 Work End N1, N2 selection direction vector V1, V2 moving direction vector F1, F2 predetermined direction pressing direction vector

Front page continuation (72) Fumio Ozaki Inventor Fumio Ozaki 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Shintaro Nagataki 2068-3 Ooka, Numazu-shi, Shizuoka Toshiba Machine Stock company Numazu Office

Claims (3)

[Claims] 1. A force control robot that moves an end effector along a surface of a work object while controlling the end effector so as to press the surface of a work object with a target pressing force. A force control robot comprising: direction setting means for setting a pressing direction of the end effector in a predetermined pressing direction defined by a moving direction of the end effector. 2. The force control robot according to claim 1, wherein the predetermined pressing direction is a direction orthogonal to the selecting direction and the moving direction of the end effector. 3. The force control robot according to claim 1, wherein the selection direction is a surface normal direction of the work object.