JP4096305B2 - Method and apparatus for automatic assembly of parts by robot - Google Patents

Description

となる。ただし、係数ｋ、Ｂ、Ｃ、Ｎは以下の関係を満足する。
【００２８】
【数２】

予め設定された螺旋軌道の接線方向の周速度をＶとするとΔｔ秒後の角度増分量Δθは
【数３】

となる。時刻Δｔ＊ｎまでの総回転角度Ａｎｇｌｅ（ｎ）は
Angle(n)＝Angle(n-1)＋Δθ(n) ・・・（式３）
となり、時刻Δｔ＊ｎの螺旋軌道上の位置（Ｓｘ（ｎ），Ｓｙ（ｎ））は
【数４】

となる。
【００２９】
変換行列
【数５】

がワールド座標系Ｗに基づく作業座標系Ｓを表すとすると、ワールド座標系Ｗを基準座標とした場合の、時刻Δｔ＊ｎの位置（Ｘ（ｎ），Ｙ（ｎ），Ｚ（ｎ））は、
【数６】

となり、時刻Δｔ＊ｎでの移動量と移動方向を示すベクトル（ΔＸ（ｎ），ΔＹ（ｎ），ΔＺ（ｎ））は
【数７】

と求まる。（式１）から（式７）までの生成を
Ｒ（ｎ−１）＞ＭａｘＸ …（式８）
になるまで繰り返し行い、デジタルサーボ回路３ｃへの移動指令として（ΔＸ（ｎ），ΔＹ（ｎ），ΔＺ（ｎ））を入力する。
【００３０】
【発明の効果】
以上述べたように、請求項１記載の発明に係る部品自動組立方法によれば、視覚センサなどが不要であるため、センサ配置問題を考慮する必要が無く、さらにセンサと部品間の干渉も考慮する必要が無いため、狭奥部でもスムーズに作業ができる。また、位置信頼度の高い点から徐々に探索範囲を広げていくため、最短の時間で軸芯探索を行うことができる。
また位置決め精度の範囲内で、軸芯を探索することができるため、不必要な範囲の探索をすることが無く、最短の探索時間で確実な軸芯探索を行うことができる。
また位置決め精度の範囲内で、基準軸に基づいて嵌合可能な軸芯を探索することができるため、最短の探索時間で確実な軸芯探索を行うことができる。
【００３１】
また両方向に回転させて複数軸芯合わせを行うため、必要十分な軸芯探索が可能である。
請求項２記載の発明に係る部品自動組立装置によれば、視覚センサなどが不要であるため、センサ配置問題を考慮する必要が無く、さらにセンサと部品間の干渉も考慮する必要が無いため、狭奥部でもスムーズに作業ができる。
【図面の簡単な説明】
【図１】 本発明の実施例に係る部品自動組立方法および装置の基本構成を示す図である。
【図２】 本発明の実施例で用いる組立対象部品の斜視図である。
【図３】 本発明の実施例で用いる組立対象部品及びその位置決めまたは部品供給を示す断面図である。
【図４】 本発明の実施例の押圧工程Ｓ２が完了した直後の第１部品５と第２部品４の位置関係を示す図である。
【図５】 本発明の実施例の押圧工程Ｓ２が完了した直後の第１部品５の穴５ａと第２部品４の軸４ａの関係を示す図（図４のＺＡ部の拡大図）である。
【図６】 本発明の実施例の基準軸探索工程Ｓ３の動作パターンを示す模式図である。
【図７】 （ａ）は作業座標系Ｓを参照座標として生成された螺旋軌道の斜視図、（ｂ）は作業座標系ＳのＸＹ平面図である。
【図８】 本発明の実施例の複数軸芯合わせ工程Ｓ４の基準軸の採用方法を示す模式図である。
【図９】 本発明の実施例の複数軸芯合わせ工程Ｓ４の基準軸周りの探索動作を示す斜視図である。
【図１０】 本発明の実施例の複数軸芯合わせ工程Ｓ４の基準軸周りの探索動作を示す、ＸＹ平面図である。
【図１１】 従来の実施例示す全体構成図である。
【図１２】 従来の実施例における軸芯合わせを示す図である。
【図１３】 従来の実施例に処理フローを示す図である。
【図１４】 他の従来例の基本構成を示す図である。
【図１５】 他の従来例における第１の部品と第２の部品を示す斜視図である。
【符号の説明】
１ チャック機構
２ ロボット
３ 制御装置
３ａ 記憶装置
３ｂ ＣＰＵ
３ｃ デジタルサーボ回路
４ 第２の部品
４ａ，４ｂ，４ｃ，４ｄ 軸部
５ 第１の部品
５ａ，５ｂ，５ｃ，５ｄ 穴部
６ 位置決め機構
７ 部品供給機構[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for automatically assembling parts by a robot, and more particularly, to an automatic part assembling method and an automatic part assembling apparatus for automatically fitting and inserting parts that require alignment of a plurality of axes.
[0002]
[Prior art]
Conventionally, in a method of automatically assembling a part that cannot be assembled unless a plurality of axes are aligned, a dedicated tool is installed at the end of the robot and each axis is aligned in advance by a visual sensor such as a CCD camera. There was a method of assembling in.
Among them, WO 98-17444 republished publication (Patent Document 1) describes an assembling method in which the shaft cores between parts are aligned in advance by a visual sensor, and then fitting and insertion are sequentially performed. Hereinafter, this assembly method will be briefly described with reference to the drawings.
[0003]
FIG. 11 is a diagram showing the overall configuration, and FIG. 12 is a conceptual diagram showing detection of the position and orientation of the convex portion of the fitting work and detection of the position and posture of the concave portion of the fitting work. In FIG. 11, E1 is a robot, E2 is a hand part of the robot E1, E3 is a force sensor provided at the tip of the hand part E2, and detects the magnitude of external force, E4 is a robot hand provided with a gripping claw E41 at the tip, E5 is a robot controller, E7 is a fitting workpiece, E71 is a convex portion of the fitting workpiece E7, E8 is a workpiece to be fitted, E81 is a concave portion of the workpiece E8 to be fitted, E9 is a positioning device, and ESU is a structure light unit. Show.
In this apparatus, a force sensor E3 attached to the hand E2 of the robot E1 detects forces in six axes for force control and sends them to the robot controller E5. The structure light unit ESU and the robot determine the position and posture of the convex portion E71 of the fitting workpiece E7 gripped by the gripping claws E41 of the robot hand E4 and the position and posture of the concave portion E81 of the workpiece E8 to be fitted positioned by the positioning device E9. Detection is performed by a three-dimensional visual sensor including an image processing unit in the control device E5, and the insertion start position of the robot is corrected. And the convex part E71 is inserted in the recessed part E81 by force control. After the insertion operation is completed, it is determined whether or not the insertion state of the fitting workpiece E7 and the fitting workpiece E8 is appropriate.
[0004]
If the sequence for one work cycle is shown in the flowchart, it will be as shown in FIG. The main points of steps S101 to S115 in this flowchart are as follows.
Step S101: The robot E1 is moved from the standby position to the taught gripping position EPH for positioning.
Step S102: The fitting work E7 is gripped by the closing operation of the claw E41 of the hand E4.
Step S103: Position the robot E1 by moving it to the taught gripping state detection position EPd.
Step S104: The position and orientation of the convex part E71 of the fitting work E7 gripped by the robot E1 are detected.
Step S105: The position and orientation of the recess E81 of the work E8 to be fitted are detected.
Step S106: The robot E1 is moved and positioned to the corrected approach position EPa ′ corrected based on the detected approach position EPa based on the detection results of steps S104 and S105.
[0005]
Step S107: The insertion operation by force control is started. Note that the details of the insertion operation by force control are generally known matters, and thus the details are omitted, but here, the impedance control of the robot E1 is executed at the above-described points. Thereby, the robot E1 is controlled to converge to a state of outputting the target force Fz set in the Y-axis direction while moving in the Y-axis direction.
Step S108: Waiting for detection of either the movement of the distance L or the elapse of the time t0 with the approach operation start as a reference.
Step S109: The robot E1 is stopped and the force control is released.
Step S110: The fitting work E7 is released by the opening operation of the claw E41 of the hand E4.
Step S111: The robot E1 is retracted to the taught retract position.
[0006]
Step S112: The position and orientation of the bottom surface E72 of the fitting work E7 gripped by the robot E1 are detected.
Step S113: It is determined whether or not the insertion state of the convex portion E71 into the concave portion E81 is satisfactory.
Step S114: If the insertion state is good, a signal indicating the good insertion state is output. Thereby, for example, “insertion good” is displayed on the attached display of the robot controller E5.
Step S115: If the insertion state is defective, an alarm signal indicating the insertion state failure is output. Thereby, for example, “insertion failure” is displayed on the attached display of the robot control apparatus E5, an alarm is sounded, and the system is urgently stopped.
[0007]
On the other hand, Japanese Patent Laid-Open No. 2002-254257 (Patent Document 2) discloses an automatic component assembly method as shown in FIGS. In FIG. 14, 1 is a chuck mechanism for gripping a second part 4 (see FIG. 15) that is a part to be assembled, and 2 is a degree of translational freedom in three directions of X, Y, and Z and around the Z-axis direction axis. A robot 3 having a rotational degree of freedom is a controller for operating the robot 2, and includes a storage device 3a, a CPU 3b, and a digital servo circuit 3c. The digital servo circuit 3c controls position and force based on a command from the CPU 3b. FIG. 15 is a perspective view showing a part to be assembled. 5 is a first part having a square hole 5a, and 4 is a first part having a shaft part 4a having a square chamfered portion into which the square hole 5a is fitted. 2 parts.
[0008]
Next, the operation of the apparatus described in Patent Document 2 will be described according to the following steps.
S201: Positioning and gripping process The robot 2 is operated based on a command of the CPU 3b, the chuck mechanism 1 grips the second component 4 supplied from the component supply mechanism (not shown), and the robot 2 is moved to move the chuck mechanism. The second part gripped by 1 is positioned above the first part 5 positioned by a positioning mechanism (not shown).
S202: The wrist of the pressing process robot 2 is lowered and the second part 4 is pressed against the first part 5 with a preset force. Then, in the process of lowering the second component 4, the second component 4 is normally slightly misaligned with respect to the first component 5. A part of the chamfered portion contacts the upper end of the hole of the first component 5.
[0009]
S203: Revolution trajectory calculation process The position of the contact point between the first component 5 and the second component 4 is known in advance because the range of deviation of the axis is known from the repeat accuracy of the robot 2, the accuracy of the positioning mechanism, and the accuracy of the component supply mechanism. The movement direction and the movement amount of the spiral trajectory type are generated with respect to the center and stored in the storage device 3a.
S204: Rotation trajectory calculation process Since the range of the rotation error of the second component 4 relative to the first component 5 is known in advance, a periodic rotation amount of forward and reverse rotation is generated and stored in the storage device 3a.
[0010]
S205: Fitting process By taking out the operation amount from the storage device 3a based on the generation results of the revolution trajectory generation step S203 and the rotation trajectory generation step S204, and operating the robot 2 while maintaining the pressing pressure in the pressing step S202. The control point of the second part 4 is moved.
S206: Insertion process When the amount of pushing movement in the fitting insertion direction calculated from the feedback position is greater than or equal to the set value during the fitting process S205, it is determined that the phase matches the axis, and the robot 2 is temporarily stopped. It is inserted and moved by a preset movement amount. When the insertion step S206 is completed, the operation of the robot 2 is stopped.
Through the above steps, the shaft core and alignment associated with the fitting and insertion of components can be performed at high speed and with high accuracy.
[0011]
[Patent Document 1]
WO98-17444 republished publication [Patent Document 2]
JP 2002-254257 A [0012]
[Problems to be solved by the invention]
However, the automatic assembly method for parts by the conventional robot described in Patent Document 1 above automatically inserts and inserts a part having a plurality of assembly axes in a narrow part that cannot be sensed by a three-dimensional visual sensor. When performing, it cannot be applied because the sensing itself is impossible due to interference between the sensor body and the part or light shielding by the part. Furthermore, even if it can be detected, there is a possibility that the three-dimensional visual sensor of the type that irradiates the laser erroneously detects due to specular reflection on the surface of the component. Further, in order to improve the actual detection accuracy, it is necessary to solve a sensor arrangement problem such as installing a sensor in advance at a position convenient for sensing. On the other hand, parts flowing through actual production lines are becoming smaller year by year in order to meet market needs, and there is an increasing demand for assembly automation in narrow spaces.
Further, in the component automatic assembly method described in Patent Document 2, it is assumed that there is a single assembly axis, and is applied when fitting and inserting a component having a plurality of assembly axes is performed automatically. There is a problem that you can not.
[0013]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to automatically and quickly and reliably perform fitting and insertion work of a part having a plurality of assembly axes by a robot without using an external sensor such as a visual sensor. It is an object of the present invention to provide an automatic parts assembly method and apparatus using a robot.
[0014]
[Means for Solving the Problems]
To solve the above problem,
The component automatic assembly method by the robot according to claim 1 is:
By a robot having a chuck mechanism, and a second component which have at least three shaft portions for mating with said plurality of holes and the first component having at least three holes which is placed on the positioning mechanism In the automatic parts assembly method,
A positioning and gripping step of positioning the second part gripped by the robot by the chuck mechanism at a reference position of the first part positioned by the positioning mechanism ;
A pressing step in which the robot presses the second component against the first component in a fitting insertion direction;
One of the plurality of shaft portions of the second part is set as a reference axis, and the maximum position deviation range estimated from the accuracy of the positioning mechanism around the contact point between the reference axis and the first part. A spiral trajectory having a maximum radius is generated, and the contact point is moved along the spiral trajectory while the robot presses the second part against the first part, and the second part is moved during the movement. reference axis searching step in which the pushing movement of the fitting insertion direction of the parts to stop moving as the axis is matched with the reference axis and the hole of the first component when it becomes more than a set value When,
The robot sequentially rotates the second part around each of the plurality of shaft parts of the second part, and the shaft part having the smallest difference between the command rotation amount and the feedback rotation amount is the reference part. Re-set as an axis, generate a periodic amount of forward / reverse rotation around the reference axis of the second part, and rotate the robot while pressing the second part against the first part by the robot When the movement amount and the posture change of the second part in the fitting insertion direction during the movement become equal to or larger than a set value during the movement, the axis other than the reference axis and the first part A multi-axis alignment process for stopping the movement when the axial centers of the holes match each other ;
And an insertion step of moving the second component relative to the first component in the fitting insertion direction .
[0019]
An automatic component assembly apparatus using a robot according to claim 2 , comprising: a robot having a chuck mechanism at a tip thereof; and a control device for controlling the operation of the chuck mechanism and the robot, and at least three mounted on a positioning mechanism In a component automatic assembly apparatus that automatically assembles a first component having a hole and a second component having at least three shaft portions that fit into the plurality of holes,
The control device includes a positioning and gripping step of positioning the second component gripped by the robot by the chuck mechanism at a reference position of the first component positioned by the positioning mechanism ;
A pressing step in which the robot presses the second component against the first component in a fitting insertion direction;
One of the plurality of shaft portions of the second part is set as a reference axis, and the maximum position deviation range estimated from the accuracy of the positioning mechanism around the contact point between the reference axis and the first part. A spiral trajectory having a maximum radius is generated, and the contact point is moved along the spiral trajectory while the robot presses the second part against the first part, and the second part is moved during the movement. reference axis searching step in which the pushing movement of the fitting insertion direction of the parts to stop moving as the axis is matched with the reference axis and the hole of the first component when it becomes more than a set value When,
The robot sequentially rotates the second part around each of the plurality of shaft parts of the second part, and the shaft part having the smallest difference between the command rotation amount and the feedback rotation amount is the reference part. Re-set as an axis, generate a periodic amount of forward / reverse rotation around the reference axis of the second part, and rotate the robot while pressing the second part against the first part by the robot When the movement amount and the posture change of the second part in the fitting insertion direction during the movement become equal to or larger than a set value during the movement, the axis other than the reference axis and the first part A multi-axis alignment process for stopping the movement when the axial centers of the holes match each other ;
And a function of executing an insertion step of moving the second component relative to the first component in a fitting insertion direction .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a basic configuration of a component automatic assembling method and apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view of components to be assembled used in the embodiment of the present invention.
In FIG. 1, 1 is a chuck mechanism for gripping a second part 4 that is an assembly target part, 2 is a translational freedom degree in three directions of X, Y, and Z, and rotations about the respective axes of X, Y, and Z A robot 3 having a degree of freedom is a control device for operating the robot 2, and includes a storage device 3a, a CPU 3b, and a digital servo circuit 3c. The storage device 3a stores operating conditions used in a reference axis search step S3 and a multi-axis alignment step S4 described later. The digital servo circuit 3c controls position and force based on a command from the CPU 3b.
[0021]
FIG. 2 is a perspective view showing parts to be assembled. Reference numeral 5 denotes a first part having holes 5a, 5b, 5c and 5d, and 4 denotes a shaft part 4a into which the holes 5a, 5b, 5c and 5d are respectively fitted. , 4b, 4c, 4d. Note that the tip of each shaft portion of the second component 4 is chamfered.
FIG. 3 is a cross-sectional view showing components to be assembled and their positioning or component supply. 6 is a positioning mechanism for positioning the first component 5, and 7 is a component supplying mechanism for supplying the second component 4 to the apparatus. is there.
[0022]
Next, the operation of the above embodiment will be described using the flowchart shown in FIG.
S1: Positioning and gripping process First, the robot 2 is operated based on a command from the CPU 3b, and the chuck mechanism 1 grips the second component 4 supplied by the component supply mechanism 7. Then, as shown in FIG. 3, the robot 2 is moved to position the second component 4 gripped by the chuck mechanism 1 above the first component 5 positioned by the positioning mechanism 6.
[0023]
S2: Pressing Step Next, the wrist 2a of the robot 2 is lowered to press the second component 4 against the first component 5 with a preset force. Then, in the process of lowering the second component 4, the second component 4 is normally slightly misaligned with respect to the first component 5. A part of the chamfered portion contacts the upper end of the hole of the first component 5.
[0024]
S3: Reference axis search process Since the range of axial misalignment is known in advance from the repeat accuracy of the robot 2, the accuracy of the positioning mechanism 6 and the accuracy of the component supply mechanism 7, as shown in FIG. Among the plurality of assembly axes of the first component 5, a spiral orbit type movement direction and movement amount are generated around the contact point position CP1 located at the tip of the axis 4a indicating the reference axis serving as an assembly reference, and digitally generated. The contact point position CP1 of the second component 4 is moved as a control point by operating the robot 2 while maintaining the pressing force input to the servo circuit 3c and achieved in the pressing step S2. If the amount of pushing movement of the second component 4 in the fitting insertion direction calculated from the feedback position in the middle of the reference axis search process becomes equal to or larger than the set value, it is determined that the axis of the axis 4a is aligned, and once the robot 2 Is stopped and the process proceeds to the multi-axis alignment process S4.
[0025]
S4: Multi-axis alignment process In this process, since the range of the rotation error is known in advance, as shown in FIG. 8, first, rotation commands around the respective axes (4a, 4b, 4c, 4d) are sequentially performed. Give it an action. Rotation around an axis other than the axis (reference axis) in which the shaft center matches the hole is restricted by the reference axis and cannot follow the command. Therefore, the axis with the smallest difference between the command rotation amount and the feedback rotation amount is adopted as the reference axis. In this embodiment, 4a is adopted as the reference axis as shown in FIGS. 9 and 10, and a periodic rotation amount of forward and reverse rotations is continuously generated around the reference axis 4a and input to the digital servo circuit 3c. The axes 4b, 4c, and 4d of the second component 4 are searched and moved by operating the robot 2 while maintaining the pressing pressure performed in the pressing step S2. If the amount of pushing movement in the fitting insertion direction and the change in posture calculated from the feedback position during the multi-axis alignment process become equal to or greater than the set value, it is determined that the axes of the shafts 4b, 4c, and 4d are aligned, Once the robot 2 is stopped, the process proceeds to the insertion step S5.
S5: Insertion step In this step, the robot 2 is inserted and moved by a preset amount of movement, and the operation of the robot 2 is stopped.
[0026]
Here, the generation method of the spiral trajectory type moving direction and moving amount in the reference axis searching step S3 will be described in detail with reference to FIGS.
5 and 6 are diagrams showing the positional relationship between the hole 5a of the first component 5 and the shaft 4a of the second component 4 immediately after the pressing step S2 is completed, and S indicates a work coordinate system. The Z axis of the work coordinate system S is opposite to the fitting insertion direction of the second part 4, and the origin of the work coordinate system S is located at the center of the tip of the axis 4 a of the second part 4.
FIG. 7A is a perspective view of a spiral trajectory generated using the work coordinate system S as a reference coordinate, and FIG. 7B is an XY plan view of the work coordinate system S. In FIG. 7A, MinY is the minimum radius of the spiral trajectory, MaxY is the maximum radius of the spiral trajectory in the Y-axis direction, and MaxX is the maximum radius of the spiral trajectory in the X-axis direction. The MaxY and MaxX set the maximum amount of the misalignment range expected from the positioning accuracy.
[0027]
The control period of the controller 3 and Delta] t, the time Delta] t (n-1) on the basis coordinates the work coordinate system S (n is an integer of 1 or more) positions on the helical trajectory at (Sx (n-1), Sy (N-1)), assuming that the total rotation angle up to time Δt (n-1) is Angle (n-1), from the origin of the work coordinate system S (Sx (n-1), Sy (n-1) The distance R (n-1) to) is

It becomes. However, the coefficients k, B, C, and N satisfy the following relationship.
[0028]
[Expression 2]

If the circumferential velocity in the tangential direction of the spiral trajectory set in advance is V, the angle increment Δθ after Δt seconds is given by

It becomes. The total rotation angle Angle (n) up to time Δt * n is
Angle (n) = Angle (n-1) + Δθ (n) (Equation 3)
The position (Sx (n), Sy (n)) on the spiral orbit at time Δt * n is

It becomes.
[0029]
Transformation matrix [Equation 5]

Represents a work coordinate system S based on the world coordinate system W, the position (X (n), Y (n), Z (n)) at time Δt * n when the world coordinate system W is used as a reference coordinate. Is
[Formula 6]

The vectors (ΔX (n), ΔY (n), ΔZ (n)) indicating the moving amount and moving direction at time Δt * n are expressed as follows:

Is obtained. The production | generation from (Formula 1) to (Formula 7) is R (n-1)> MaxX ... (Formula 8).
Are repeated until (ΔX (n), ΔY (n), ΔZ (n)) is input as a movement command to the digital servo circuit 3c.
[0030]
【The invention's effect】
As described above, according to the component automatic assembly method according to the first aspect of the present invention, since a visual sensor or the like is unnecessary, it is not necessary to consider the sensor placement problem, and further, interference between the sensor and the component is also considered. Since there is no need to do this, it is possible to work smoothly even in a narrow interior. In addition, since the search range is gradually expanded from the point with high position reliability, the axial center search can be performed in the shortest time.
Further , since the axis can be searched within the range of positioning accuracy, an unnecessary range is not searched, and a reliable axis search can be performed in the shortest search time.
In addition, within the range of positioning accuracy, it is possible to search for an axis that can be fitted based on the reference axis, so that a reliable axis search can be performed in the shortest search time.
[0031]
In addition , since a plurality of axes are aligned by rotating in both directions, a necessary and sufficient axis center search is possible.
According to the component automatic assembly apparatus according to the invention of claim 2 , since a visual sensor or the like is unnecessary, there is no need to consider a sensor arrangement problem, and further, there is no need to consider interference between the sensor and the component. You can work smoothly even in a narrow area.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic configuration of an automatic parts assembly method and apparatus according to an embodiment of the present invention.
FIG. 2 is a perspective view of a part to be assembled used in an embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a part to be assembled and its positioning or part supply used in an embodiment of the present invention.
FIG. 4 is a diagram showing a positional relationship between the first part 5 and the second part 4 immediately after the pressing step S2 of the embodiment of the present invention is completed.
5 is a diagram (an enlarged view of a ZA portion in FIG. 4) showing the relationship between the hole 5a of the first component 5 and the shaft 4a of the second component 4 immediately after the pressing step S2 of the embodiment of the present invention is completed. .
FIG. 6 is a schematic diagram showing an operation pattern of a reference axis searching step S3 according to the embodiment of the present invention.
7A is a perspective view of a spiral trajectory generated using the work coordinate system S as reference coordinates, and FIG. 7B is an XY plan view of the work coordinate system S. FIG.
FIG. 8 is a schematic diagram showing a method for employing a reference axis in the multi-axis alignment step S4 according to the embodiment of the present invention.
FIG. 9 is a perspective view showing a search operation around the reference axis in the multi-axis alignment step S4 according to the embodiment of the present invention.
FIG. 10 is an XY plan view showing a search operation around the reference axis in the multi-axis alignment step S4 according to the embodiment of the present invention.
FIG. 11 is an overall configuration diagram showing a conventional example.
FIG. 12 is a diagram showing alignment of axes in a conventional example.
FIG. 13 is a diagram showing a processing flow in a conventional example.
FIG. 14 is a diagram showing a basic configuration of another conventional example.
FIG. 15 is a perspective view showing a first part and a second part in another conventional example.
[Explanation of symbols]
1 Chuck mechanism 2 Robot 3 Controller 3a Storage device 3b CPU
3c Digital servo circuit 4 Second parts 4a, 4b, 4c, 4d Shaft part 5 First parts 5a, 5b, 5c, 5d Hole part 6 Positioning mechanism 7 Part supply mechanism

Claims (2)

By a robot having a chuck mechanism, and a second component which have at least three shaft portions for mating with said plurality of holes and the first component having at least three holes which is placed on the positioning mechanism In the automatic part assembly method,
A positioning and gripping step of positioning the second part gripped by the robot by the chuck mechanism at a reference position of the first part positioned by the positioning mechanism ;
A pressing step in which the robot presses the second component against the first component in a fitting insertion direction;
One of the plurality of shaft portions of the second part is set as a reference axis, and the maximum position deviation range estimated from the accuracy of the positioning mechanism around the contact point between the reference axis and the first part. A spiral trajectory having a maximum radius is generated, and the robot moves the contact point along the spiral trajectory while pressing the second part against the first part by the robot . reference axis searching step in which the pushing movement of the fitting insertion direction of the parts to stop moving as the axis is matched with the reference axis and the hole of the first component when it becomes more than a set value When,
The robot sequentially rotates the second part around each of the plurality of shaft parts of the second part, and the shaft part having the smallest difference between the command rotation amount and the feedback rotation amount is the reference part. Re-set as an axis, generate a periodic amount of forward / reverse rotation around the reference axis of the second part, and rotate the robot while pressing the second part against the first part by the robot When the movement amount and the posture change of the second part in the fitting insertion direction during the movement become equal to or larger than a set value during the movement, the axis other than the reference axis and the first part A multi-axis alignment process for stopping the movement when the axes of the holes are aligned with each other ;
An automatic component assembly method using a robot, comprising: an insertion step of moving the second component in the fitting insertion direction with respect to the first component. A first component having at least three holes placed on a positioning mechanism and a plurality of holes, comprising: a robot having a chuck mechanism at a tip; and a controller for controlling the operation of the chuck mechanism and the robot. In an automatic component assembly apparatus for automatically assembling a second component having at least three shaft portions to be fitted to the portion,
The controller is
A positioning and gripping step of positioning the second part gripped by the robot by the chuck mechanism at a reference position of the first part positioned by the positioning mechanism ;
A pressing step in which the robot presses the second component against the first component in a fitting insertion direction;
One of the plurality of shaft portions of the second part is set as a reference axis, and the maximum position deviation range estimated from the accuracy of the positioning mechanism around the contact point between the reference axis and the first part. A spiral trajectory having a maximum radius is generated, and the robot moves the contact point along the spiral trajectory while pressing the second part against the first part by the robot . reference axis searching step in which the pushing movement of the fitting insertion direction of the parts to stop moving as the axis is matched with the reference axis and the hole of the first component when it becomes more than a set value When,
The robot sequentially rotates the second part around each of the plurality of shaft parts of the second part, and the shaft part having the smallest difference between the command rotation amount and the feedback rotation amount is the reference part. Re-set as an axis, generate a periodic amount of forward / reverse rotation around the reference axis of the second part, and rotate the robot while pressing the second part against the first part by the robot When the movement amount and the posture change of the second part in the fitting insertion direction during the movement become equal to or larger than a set value during the movement, the axis other than the reference axis and the first part A multi-axis alignment process for stopping the movement when the axes of the holes are aligned with each other ;
An insertion step of moving the second component in the fitting insertion direction with respect to the first component;
A part automatic assembly apparatus using a robot characterized by having a function of executing

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