JPH079304A - Correcting method for correctingly positioning elastic deformation of mechanical structure - Google Patents

Abstract

PURPOSE:To improve the positioning accuracy by detecting an elastic deformation generated to a frame by the function of an external force with a displacement sensor, giving the resultant output to a thrust actuator controller so as to generate a correcting thrust, and controlling to make an appearant force operating to the frame zero. CONSTITUTION:When an external force operates to the upper piece 1b of a frame 1, an elastic deformation is generated to the frame 1 by a compliance of the frame 1. This elastic deformation is detected by a displacement sensor 7 installed to a column 1a. The detected output is feedbacked to the controller 4 of a thrust device A. A thrust actuator 3 generates a thrust F proportional to the input signal input from the controller 4 through a driver 5, and the thrust F is applied to the upper piece 1b of the frame 1 so as to deny the external force L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of correcting elastic deformation of a frame, which is caused by an external force acting on a mechanical structure, by using a thrust device and a displacement detector.

[0002]

2. Description of the Related Art When a C-shaped frame of a conventional mechanical structure is subjected to an external force, it is elastically deformed. Therefore, in order to eliminate elastic deformation, there are generally unavoidable gate-shaped structures.

It is also known to use a robot which holds a tool unit and cuts a workpiece.

[0004]

In the former case of the above-mentioned prior art, it is difficult and difficult to make a frame-shaped frame in order to prevent elastic deformation, and there is a defect in workability in use.

Further, in the latter case, there is a problem that the allowable deformation is limited and a large rigidity is required, and accordingly, it becomes large.

[0006]

In order to solve the above-mentioned problems, the present invention detects the elastic displacement generated in the frame part by an external force by a displacement detection sensor, and outputs this output to a thrust actuator control part to correct thrust. The present invention provides a correction method in which the correction force is generated so that the apparent force acting on the frame becomes zero, and the correction positioning is performed so that the deformation of the frame is corrected.

[0007]

The operation will be described with reference to the servo system block diagram of FIG. A displacement detection sensor 7 provided in the frame 1 detects a displacement δ generated in the frame due to the compliance C (flexibility) of the frame 1 on which the external force L acts, and this output is composed of a control unit 4, a driver 5, and an actuator 3. Thrust device A
The actuator 3 is fed back to the controller 4 to generate a corrected thrust F so as to cancel the external force L, and the actuator 3 is controlled so that the apparent force acting on the frame becomes zero, so that the deformation of the frame is corrected.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings are embodiments of a method for correcting elastic deformation of a mechanical structure of the present invention, which will be described in detail below.

FIG. 1 shows an example of elastic deformation correction in the case of a C-shaped frame, and 1 is a frame in which an upper piece 1b and a lower piece 1c are integrally provided in the horizontal direction above and below a column portion 1a. Reference numeral 2 denotes a mounting stand to which the thrust actuator 3 of the thrust device A including the control unit 4, the driver 5, and the thrust actuator 3 is mounted, and is provided outside the frame 1. The mounting stand 2 is bent in the upper lateral direction, and the thrust actuator 3 is attached to the lower surface of the bending piece 2a, and the mover 6 of the thrust actuator 3 is coupled to the upper surface of the upper piece 1b of the frame 1.

FIG. 2 is a block diagram of the servo system shown in FIG.
The upper piece 1 of the frame 1 for explaining FIG. 1 by this diagram
An external force L acts on b, and the compliance C of the frame 1 causes elastic deformation δ of the frame 1. The elastic deformation δ is detected by the displacement sensor 7 attached to the column portion 1a, and the output detected by the displacement sensor 7 is fed back to the control unit 4 of the thrust device A. The thrust actuator 3 generates a thrust F proportional to the input signal from the control unit 4 via the driver 5, and the thrust F cancels the external force L.

The force acting on the frame 1 is apparently zero, and the deformation of the frame 1 is corrected.

The mounting stand 2 is deformed by the reaction force of the thrust force F as shown by the dotted line, but only the force is transmitted and has nothing to do with the deformation correction function.

In FIG. 3, the workpiece W is mounted on the base 11 in the correction method using the vertical surface grinder.
A column 12 stands up at one end of the column 12, and a whetstone head 13 having a whetstone 13a provided downward is attached to the column 12. The grindstone head 13 is moved downward along the column 12 so that the workpiece W is cut and fed.

A mounting stand 15 for mounting the thrust actuator 14 is provided on the back surface of the column 12, and one end of the thrust actuator 14 is mounted on the mounting stand 15.
Then, the movable element 16 at the other end is coupled to the column 12.

A displacement detecting sensor 17 is provided on the column 12.

The output of the displacement detection sensor 17 is fed back to the control unit 18 of the thrust device including the control unit 18, the driver 19 and the thrust actuator 14. This feedback is sent to the actuator 1 via the driver 19.
4 applies a correction thrust F proportional to the displacement (processing reaction force) L to the column 12 and controls so that the displacement of the column 12 becomes zero.

Next, a third embodiment shown in FIG. 4 corrects the displacement of the arm of a robot that cuts a workpiece placed on a base by using a general-purpose robot to correct the workpiece W placed on the base 21. The power tool unit 22 is held by the hand portion H of the machining robot R, and the workpiece W is cut by the power tool unit 22 along the movement program path.

The processing reaction force L at the time of cutting acts on the arm 23 of the processing robot R, and the arm 23 is elastically deformed. This elastic deformation is detected by the displacement detecting sensor 24 provided on the arm 23.

In the machining robot R, a correction robot Ra is arranged at an opposing position with the workpiece W in between. The hand Ha of the correction robot Ra is the thrust actuator 2
5, the operation of the correction robot Ra is programmed so that one end of the thrust actuator 25 is located above the hand H of the processing robot R.

The output of the displacement detection sensor 24 for detecting the displacement of the arm 23 of the processing robot R is fed back to the control unit 26 of the thrust actuator 25 of the thrust device including the thrust actuator 25, the control unit 26 and the driver 27. Servo system is driver 27, actuator 2
A correction thrust F proportional to the displacement (processing reaction force L) is generated via 5, and the correction robot Ra presses the hand H of the processing robot R downward to set F = L. That is, the displacement of the arm 23 of the processing robot is controlled to be zero.

The deformation of the arm 23 of the machining robot R is corrected, and the tool unit 22 is positioned at a position according to the program to prevent machining error from occurring.

FIG. 5 is a fourth embodiment showing the correction of the load force of the sliding table, which is a guideway 32 provided on the base 31.
One end of the sliding table 33 which is slidably fitted into and slides on is screwed with the feed screw shaft 34, and the other end of the feed screw shaft 34 is rotatably supported by a support bracket 35 and is rotated by a motor 36 attached to the support bracket 35. Has been.

The other end of the sliding table 33 is the base 31.
It is connected to the mover 38 of the thrust actuator 37 provided above.

A displacement sensor 39 for detecting elastic deformation of the bracket 35 is provided on the support bracket 35 on which the screw shaft 34 is supported, and the displacement output detected by the displacement sensor 39 controls the thrust actuator 37. I give feedback to 40.

This correction is performed by rotating the feed screw shaft 34 by the feed motor 36 by θ ° to move the sliding table 33 leftward. When moved by θ / 360 (P = pitch), the load force L acts on the sliding table 33. The force is transmitted to the base 31, the sliding table 33, the feed screw shaft 34, the support bracket 35, and the base 31, and the screw shaft support bracket 35 elastically deforms δ as shown by the dotted line by the load force. The sliding table 33 (target movement value is P.θ
/ 360-moves only bracket displacement δ).

The displacement of the support bracket 35 is detected, and the detected output is fed back to the control section 40 of the actuator 37, and the servo system drives the driver 41 and the actuator 3.
The corrected thrust F is generated via 7 and is applied to the sliding table 33.
In addition, control is performed so that F = L. That is, δ is set to zero.

FIG. 6 shows a fourth embodiment for correcting the position of a workpiece supported by both centers. The workpiece W comprises a headstock 42 on a traverse table 41 and a spindle center 42a of a tailstock 43. Both centers 42a, between the tailstock shaft centers 43a,
The grinding wheel 44 is supported by 43a and is moved left and right with respect to the grinding wheel 44, and is ground by the rotation of the grinding wheel 44 driven by the motor 45.

A thrust actuator 46 is provided outside the traverse table 41 in correspondence with the grinding wheel 44, and a mover 47 of this thrust actuator 46 is provided in contact with the workpiece W.

The point of action of the grinding force L exerted on the workpiece W moves as the traverse traverses the left-right movement, and the elastic deformation amount of the workpiece W and the elastic deformation amount of the supporting portion change. Like this, the cylindricity of the workpiece W is adversely affected.

Force detection sensors 48 and 48a are provided on the headstock 42 and tailstock 43 to detect the supporting reaction forces Ll and Lr of the grinding force L.

The detection output Ll + Lr = L is fed back to the control section 49 of the actuator 46.

The servo system generates a correction force F through the driver 50 and the actuator 46, and controls the control unit 49 so that F = L.

When F = L, the force acting on the spindle center 42a and the tailstock shaft center 43a becomes zero, and the deformation and displacement of the workpiece W become zero.

Therefore, a high cylindricity is assured even when grinding a slender and flexible work piece.

[0035]

EFFECTS OF THE INVENTION When elastically deformed by a processing reaction force, it is ground obliquely and the parallelism accuracy is poor. Further, in the case of the machining robot, the deformation of the arm is corrected to prevent the positioning machining error from occurring in the position of the tool as programmed. Further, even if a large load force is applied to the table, accurate positioning can be performed by applying the corrected thrust force using the actuator.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a correction method of a first embodiment using a C-shaped frame as a correction method for elastic deformation of a mechanical structure.

FIG. 2 is a block diagram of a servo system.

FIG. 3 is an explanatory view of a second embodiment using a vertical surface grinder.

FIG. 4 is an explanatory diagram of a third embodiment by cutting using a general-purpose robot.

FIG. 5 is an explanatory diagram of a fourth embodiment of correcting the load force of the sliding table.

FIG. 6: Fifth position correction of the workpiece supported by both centers
It is explanatory drawing of an Example.

[Explanation of symbols]

 1 frame 1a, 12 column part 1b upper piece 1c lower piece 2,15 mounting stand 2a bending piece 3,14,25,37,46 thrust actuator 4,18,26,40,49 control section 5,19,27,41 , 50 driver 6,16,38,47 mover 7,17,24,39 displacement sensor 11,21,31 base 13 grinding wheel head 13a, 44 grinding wheel 22 tool unit 23 arm 32 guideway 33 sliding table 34 feed screw Axis 35 Support bracket 36,45 Motor 41 Traverse table 42 Headstock 42a Spindle center 43 Tailstock 43a Tailstock shaft center 48,48a Force detection sensor L External force R, Ra Robot W Workpiece F Correcting force

Front Page Continuation (72) Inventor Akira Kanai 3-50-1, Minamimachi, Higashiyamato-shi, Tokyo 2-105 Maruyamadai (72) Inventor Seisho Daito 1-18-27 Izumi 1-chome, Hamamatsu City, Shizuoka Prefecture

Claims (1)

[Claims] 1. An elastic force is deformed by compliance due to the action of an external force, the elastic deformation is detected by a displacement detection sensor, and the detection output is fed back to the control unit of a thrust device including a control unit, a driver, and a thrust actuator for control. The thrust device and displacement detector are characterized by generating a corrected thrust force through the actuator, driver, and thrust actuator, and applying this corrected thrust force to the external force so that the sum of the corrected thrust force and the external force becomes zero. Method for elastic deformation of mechanical structures that have been used.