JP2007185743A - Robot device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a robot device which can precisely detect distortions of arms thereof, and correctly stops the arms at set locations irrespective of the distortions of the arms. <P>SOLUTION: The robot device is formed of the arms 21, 31 which are operated for gripping, taking out, attaching, or conveying a workpiece, an operation control means 61 for controlling operations of the arms 21, 31, and distortion gauges 41A, 41B, 51A, 51B arranged on both sides of the arms 21, 31, respectively. Then the operation control means 61 adjusts the operations of the arms 21, 31, based on the distortions of the arms 21, 31 detected by the distortion gauges 41A, 41B, 51A, 51B, and thus the arms can be correctly stopped at the set locations irrespective of the distortions of the arms 21, 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a robot apparatus in which a strain gauge is provided on an arm.

  2. Description of the Related Art Conventionally, a robot apparatus including an arm is frequently used in various fields such as gripping, assembling, taking out, and conveying a workpiece such as a part.

  However, in the robot apparatus, the arm may go out of the set stop position due to a temperature change. For example, if the arm stop position is controlled and set based on the length and shape of the arm at the start of work when the work place temperature is low, and the work place temperature rises in the afternoon, the length and shape of the arm However, since the arm is different from the state at the start of work, the arm stops at a position out of place from the stop position set at the start of work, and the target work, for example, gripping of the work may fail.

  It has been proposed that a strain gauge is provided on one side of the arm to detect the strain of the arm, and the operation of the arm is adjusted according to the amount of strain. In many cases, the arm does not extend or contract, so that the distortion of the arm cannot be detected accurately and the arm cannot be stopped at the set stop position.

JP-A-8-118284

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a robot apparatus capable of accurately detecting arm distortion and stopping the arm correctly at a set position.

  The present invention comprises an arm, an operation control means for controlling the operation of the arm, and a strain gauge provided in the arm, and the operation of the arm is controlled based on the strain of the arm detected by the strain gauge. In the robot apparatus adjusted by the control means, the strain gauges are provided on both sides of the arm, and the operation of the arm is adjusted based on the arm strain detected by the strain gauges on both sides.

  According to the present invention, since the arm stop position is adjusted based on the arm strain detected by the strain gauges provided on both sides of the arm, the arm stop position accuracy is higher than when the strain gauge is provided on one side of the arm. Can be increased. In particular, when arm distortion is uneven on both sides of the arm and the arm bends to one side, the arm stop position is adjusted by accurately detecting the arm distortion using strain gauges provided on both sides of the arm. Therefore, the arm stop position accuracy can be further improved.

  Embodiments of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing a robot apparatus according to an embodiment of the present invention.

  The robot apparatus 10 shown in FIG. 1 includes a column 11, a first arm 21, a second arm 31, a gripping device 35, first arm strain gauges 41A and 41B, second arm strain gauges 51A and 51B, and an operation control means 61. Is provided.

  The support 11 is erected on a base (not shown) to hold the first arm 21 and the second arm 31 via the first arm 21.

  The first arm 21 is attached to the column 11 at one end and is held in a substantially horizontal direction. The first arm 21 has a required length and has a strength capable of holding the second arm 31.

  The second arm 31 is held by the first arm 21 so as to be in a direction B substantially perpendicular to the length direction A of the first arm 21. Further, the second arm 31 is movable along the length direction A of the first arm 21 by the first motor M1, and is substantially the same as the length direction of the first arm by the second motor M2. It is possible to move along the orthogonal direction B. The operation (movement) of the second arm 31 by the first motor M1 can be performed by an appropriate driving method. As an example, the second arm 31 is driven by a chain drive. In addition, the operation (movement) of the second arm 31 by the second motor M2 can be performed by an appropriate driving method, and an example is a rack and pinion mechanism.

  The gripping device 35 is a chuck device capable of gripping a workpiece such as a component, and is provided at the tip of the second arm 31.

  The first arm strain gauges 41 </ b> A and 41 </ b> B are provided on both sides of the first arm 21 and detect the strain of the first arm 21. Both sides of the first arm 21 provided with the first arm strain gauges 41A and 41B are both sides in a direction in which the first arm deforms due to a temperature change. Further, the positions of the first arm strain gauges 41A and 41B on both sides of the first arm 21 are set to appropriate positions. However, the strain of the first arm 21, particularly the bending of the first arm 21, is further increased. In order to be able to detect correctly, it is preferable to provide in a symmetrical position as shown in FIG. When the first arm strain gauges 41A and 41B are provided on both sides of the first arm 21 so as to be in the symmetrical position, for example, the side on which the first arm strain gauge 41A is provided and the second arm use When the strain amount of the first arm 21 is different from the side where the strain gauge 41B is provided, the strain on both sides of the first arm 21 can be detected correctly, and the first arm 21 can be detected on either side. It is possible to accurately detect how much is bent.

  The second arm strain gauges 51 </ b> A and 51 </ b> B are provided on both sides of the second arm 31 and detect the strain of the second arm 31. The positions of the second arm strain gauges 51A and 51B on both sides of the second arm 31 are set to appropriate positions, but are provided at symmetrical positions for the same reason as the first arm strain gauges 41A and 41B. It is preferred that As the first arm strain gauges 41A and 41B and the second arm strain gauges 42A and 42B, known ones can be used.

  The operation control means 61 controls the operation of the first motor M1, the second motor M2, and the gripping device 35, and the first arm strain gauges 41A, 41B and the second arm strain gauges 51A, Based on the distortion detection by 51B, the operation of the first motor M1 and the second motor M2 is adjusted, and the gripping device 35 at the tip of the second arm 31 is controlled to move to a preset stop position. The operation control means 61 includes a control circuit 62, a controller 63, and AMPs 64, 65 and 66.

  The control circuit 62 includes a CPU, and the tip position of the second arm 31, that is, the stop position of the gripping device 35 is set in advance, and the state of the first arm 21 and the second arm 31 at a predetermined temperature is set. The operation amounts of the first motor M1 and the second motor M2 are set according to the stop position of the gripping device 35 with reference to the reference. The control circuit 62 is connected to the first arm strain gauges 41A and 41B and the second arm strain gauges 51A and 51B, and the first arm strain gauges 41A and 41B and the second arm strain gauges. Based on the distortion detection signals input from 51A and 51B, the positions of the first arm 21 and the second arm 31 are calculated. Based on the calculated value, the operations of the first motor M1 and the second motor M2 are adjusted in order to correctly move the tip of the second arm 31, that is, the gripping device 35 to the set stop position. Is output to the controller 63. The position calculation of the first arm 21 and the second arm 31 by detecting the strain of the strain gauge is performed by, for example, calculating the strain detection amount by one side strain gauge as A (plus in the case of extension deformation, and positive in the case of contraction deformation). Minus), the strain detection amount by the strain gauge on the other side is B (plus in the case of expansion deformation, minus in the case of contraction deformation), the reference position of the arm is C, the position correction amount of the arm is D, and after the correction Assuming that the arm position is E and the experimentally obtained correction coefficient is a, the corrected arm position E can be obtained by E = C + D and D = (A−B) × a. The control circuit 62 also outputs a control signal for the gripping device 35 to the controller 63.

  The controller 63 is connected to the first motor M1, the second motor M2, and the gripping device 35 via AMPs 64, 65, and 66, respectively, and according to a control signal from the control circuit 62, the first motor M1, The operation of the second motor M2 and the gripping device 35 is controlled.

  In the above-described embodiment, an example in which the second arm can be moved (advanced / retracted) along the first arm and moved in a direction substantially orthogonal to the first arm (advanced / retracted) has been shown. In the present invention, at least one of the first arm or the second arm may rotate. Moreover, in the said embodiment, although the example provided with two arms of a 1st arm and a 2nd arm was shown, this invention is applicable also when the number of arms is one, or when it is three or more. it can. Furthermore, in the embodiment, one strain gauge, that is, one set of strain gauges, is provided on each side of the arm, but at least one set may be provided. For example, two or more sets of strain gauges may be provided, or the number of strain gauges may be different on one side and the other side of the arm. Furthermore, in the above-described embodiment, an example is shown in which strain gauges are provided only on one side of the arm (both sides in the horizontal direction), but strain gauges may be provided on both sides in the other direction (both sides in the vertical direction). Moreover, although the example which provided the holding apparatus in the front-end | tip of an arm was shown in the said embodiment, this invention is not restricted to a holding apparatus, A drill and another apparatus may be sufficient.

It is a schematic block diagram which shows the robot apparatus in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Support | pillar 21 1st arm 31 2nd arm 35 Gripping device 41A, 41B 1st arm strain gauge 51A, 51B 2nd arm strain gauge M1 1st motor M2 2nd motor

Claims (1)

An arm, an operation control means for controlling the operation of the arm, and a strain gauge provided on the arm, and adjusting the operation of the arm by the operation control means based on the strain of the arm detected by the strain gauge. In the robot device that
A robot apparatus, wherein the strain gauges are provided on both sides of the arm, respectively, and the operation of the arm is adjusted based on the arm strain detected by the strain gauges on both sides.

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