TW202005765A - Robotic arm calibration system and robotic arm calibration method - Google Patents

Abstract

A robotic arm correction system including a platform, two sets of optical sensing devices, and a controller is provided. The two sets of optical sensing devices are arranged on the platform, and the intersections of the two sensing beams emitted by the two sets of optical sensing devices overlap the calibration point of the platform in the orthographic projection of the platform. The controller is adapted to move the robotic arm to pass through at least two different positions of each of the sensing beams to record a set of sensing coordinates of the corresponding platform. The controller controls the robotic arm to rotate for an angle and repeats the above process to record another set of sensing coordinates, and then the controller calculates the corrected coordinates of the robotic arm based on the two sets of sensing coordinates. In addition, a robotic arm correction method is also provided.

Description

Robotic arm calibration system and calibration method

The invention relates to a correction system and a correction method, and in particular to a correction system and a correction method of a robot arm.

In the manufacturing industry, many processing steps are single and repeated. At present, manpower is gradually replaced by mechanical means, and the use of machines to perform processing can help increase product output and reduce manpower expenditure. In addition, the processing path is controlled by the program, which can reduce the uncertainty when using human power processing, so the application of machine processing has become a better choice in the production process of various products.

However, in today's manufacturing, samples are transferred to different machines through a robotic arm to carry out different stages of the process. However, the robotic arm is prone to vibration or jitter during the transportation of the sample due to some unexpected factors, or the actual operation may deviate from the originally planned path. Sometimes the subtlety of these vibrations or jitters is not easy to be noticed by human eyes, but it will have a serious impact on the sample handling process. Therefore, in the process of carrying the sample, if the sample is dropped or damaged due to the vibration or shaking of the robot arm, it may cause a considerable loss. In addition, at present, the method of human eye correction is often used in the calibration process of the robotic arm. Therefore, it is easy to cause deviations due to the correction of different operators, and the method of using the human eye correction is prone to errors and lead to correction accuracy. Not good.

The invention provides a mechanical arm calibration system and a calibration method, which can achieve rapid calibration without additional marking or additional tools.

The invention provides a correction system for a mechanical arm, which is suitable for correcting a mechanical arm. The robotic arm calibration system includes a platform, two sets of optical sensing devices and a controller. The two sets of optical sensing devices are arranged on the platform, and the orthographic projection of the connection lines of the two sensing beams emitted by the two sets of optical sensing devices on the platform overlaps the correction points of the platform. The controller is electrically connected to the robot arm, and is suitable for moving the robot arm to pass the two sensing beams. The controller controls the robot arm to pass through at least two different positions of each sensing beam to record a set of sensing coordinates of the corresponding platform. The controller controls the robot arm to rotate by an angle and repeats the above process to record another corresponding set of sensing coordinates, and then the controller calculates the calibration coordinates of the robot arm according to the two sets of sensing coordinates.

In an embodiment of the present invention, the two sensing beam lines of the above two sets of optical sensing devices are perpendicular to each other.

In an embodiment of the invention, the above two sets of optical sensing devices are optical fiber sensors.

In an embodiment of the invention, the above-mentioned controller controls the robot arms to move from the four different starting points toward the corresponding sensing beams, respectively. When the robot arm touches the corresponding sensing beam, the controller controls the robot arm to stop moving, and records the corresponding sensing coordinates.

In an embodiment of the invention, the above-mentioned controller controls the robot arm to move in a mouth shape from the starting point, so as to successively touch different positions of the two sensing beams.

The invention also proposes a robotic arm calibration method, including: (a) providing a robotic arm calibration system, including a platform, two sets of optical sensing devices arranged on the platform, and a controller electrically connected to the robotic arm; (b) starting two sets The optical sensing device generates two sensing beams and forms an intersection at the calibration point of the platform; (c) controls the robot arm to pass through at least two different positions of each sensing beam; (d) records a set of sensing coordinates corresponding to the platform ; (E) control the mechanical arm to rotate by an angle; (f) repeat the above steps (b) ~ (c); (g) record another corresponding set of sensing coordinates; and (h) according to the two sets of sensing coordinates Calculate the calibration coordinates of the robotic arm.

In an embodiment of the present invention, the two sensing beam lines of the above two sets of optical sensing devices are perpendicular to each other.

In an embodiment of the invention, the above two sets of optical sensing devices are optical fiber sensors.

In an embodiment of the present invention, the step of controlling the robot arm to pass through at least two different positions on each sensing beam further includes: controlling the robot arm to move from the four different starting points toward the corresponding sensing beam respectively, when When the robot arm touches the corresponding sensing beam, the robot arm is controlled to stop moving.

In an embodiment of the present invention, the step of controlling the robotic arm to pass through at least two different positions on each sensing beam further includes: controlling the robotic arm to move in a zigzag pattern from the starting point to touch the two sensing beams successively Different locations.

Based on the above, in the robotic arm calibration system and the robotic arm calibration method of the present invention, the robotic arm touches at least two different positions of the two sensing beams generated by the two sets of optical sensing devices through the movement of the controller, And record a set of sensing coordinates according to the touched position, then after controlling the robot arm to rotate an angle, repeat the above process to record another set of sensing coordinates, and finally calculate the machinery according to these two sets of sensing coordinates The calibration coordinates of the arm. Therefore, no additional marking or additional tools are needed to achieve fast calibration.

In order to make the above-mentioned features and advantages of the present invention more obvious and understandable, the embodiments are specifically described below in conjunction with the accompanying drawings for detailed description as follows.

FIG. 1 is a schematic side view of a robot arm calibration system and a robot arm according to an embodiment of the invention. FIG. 2 is a schematic top view of the robotic arm correction system of FIG. 1. Please refer to FIGS. 1 and 2. In this embodiment, the arm calibration system 100 is adapted to calibrate the robot arm 50. The arm calibration system includes a platform 110, two sets of optical sensing devices 120, and a controller 130. The two sets of optical sensing devices 120 are disposed on the platform 110, and the orthographic projection of the connection point I of the two sensing beams L emitted by the two sets of optical sensing devices 120 on the platform 110 overlaps the calibration point C of the platform 110. In this embodiment, the robot arm 50 is, for example, a four-axis robot arm for industrial processing, but it may also be a three-axis robot arm, and the present invention is not limited thereto.

The optical sensing device 120 is, for example, an optical fiber sensor or other optical sensors that can generate a linear beam, and the invention is not limited thereto. Each set of optical sensing devices 120 is relatively arranged on the platform, and two sets of optical sensing devices 120 are arranged in a cross configuration on the platform 110. In detail, in this embodiment, one set of optical sensing devices 120_1 is disposed at the midpoints of two opposite sides of the platform 110, and the other set of optical sensing devices 120_2 is disposed between the other two opposite sides of the platform 110 At the point, the connection lines of the sensing beams L emitted by the two sets of optical sensing devices 120_1 and 120_2 are perpendicular to each other, and the intersection point I is formed at the calibration point C of the platform 110, as shown in FIG. 3. In this embodiment, the calibration point C is the center point of the platform 110, so the robot arm 50 after calibration can have a maximum working range, but the present invention is not limited to this.

The controller 130 is electrically connected to the robot arm 50. When the robot arm 50 is calibrated, the controller 130 is adapted to move the robot arm 50 to pass the sensing beam L. In addition, when the robotic arm 50 touches the sensing beam L, the controller 130 is adapted to record the corresponding sensing coordinates, and after multiple movements, obtain a set of sensing coordinates.

FIG. 3 is a plan view of the movement path of the robot arm in one embodiment. Referring to FIG. 3, in the calibration method of this embodiment, the controller 130 controls the robot arm 50 to move from four different starting points toward the corresponding sensing beams L1, L2 to form four different positions A1, A2, A3, A4, and record four different positions A1, A2, A3, A4 as a set of sensing coordinates. And when the robot arm 50 touches the corresponding sensing beams L1, L2, the controller 130 controls the robot arm 50 to stop moving. In detail, the controller 130 first controls the robot arm 50 to move from the position P1 to the position A1, and records the first coordinate (ie, position A1) by the optical sensing device 120_1. Then, the controller 130 moves the robot arm 50 to the position P2, and controls the robot arm 50 to move from the position P2 to the position A2, and is recorded as the second coordinate (ie, position A2) by the optical sensing device 120_1. Therefore, the linear equation of the sensing beam L1 emitted by the optical sensing device 120_1 can be calculated by the first coordinate and the second coordinate.

In the above embodiment, the controller 130 further controls the robot arm 50 to move from the position P3 to the position A3, and is recorded as the third coordinate (ie, position A3) by the optical sensing device 120_2. Then, the controller 130 moves the robot arm 50 to the position P4, and controls the robot arm 50 to move from the position P4 to the position A4, and records the fourth coordinate (ie, position A4) by the optical sensing device 120_2. Therefore, the linear equation of the sensing beam L2 emitted by the optical sensing device 120_2 can be calculated by the third coordinate and the fourth coordinate. In other words, the controller 130 controls the robotic arm 50 to pass through at least two different positions on each sensing beam L to calculate the straight line equation of the beam from the corresponding coordinates. Therefore, the coordinates of the intersection point I of the connection line between the sensing beam L1 and the sensing beam L2 can be calculated by the linear equation of the sensing beam L1 and the linear equation of the sensing beam L2. In this way, the above process can be repeated after the robot arm 50 rotates to another angle to obtain the coordinates of another intersection point, and then calculate the calibration coordinates of the robot arm 50.

、第二座標

、第三座標

以及第四座標

，且感測光束L1及感測光束L2的直線方程式及連線交點I（即校正座標）可經由下列公式（1）至公式（4）計算得出：

----------------- （1）

---------------- （2）

----------------------------------- （3）

-------------------- （4） 其中，公式（1）為感測光束L1的直線方程式，公式（2）為感測光束L2的直線方程式，公式（3）為連線交點I的X座標，公式（4）為連線交點I的Y座標。因此，藉由上述公式計算得出連線交點座標後，藉由控制器130將機械手臂50沿中心軸U旋轉 180度，再次進行校正流程以藉由上述公式計算得到另一連線交點座標，進而根據兩連線交點座標以得出校正座標而完成校正。如此一來，可不需額外在平台110上進行額外標記或配置附加工具，進而達到快速的校正。在一些實施例中，將機械手臂50沿中心軸U所選旋轉的角度亦可以為90度、270度或其他角度，本發明並不限於此。In the above embodiment, the coordinates of the robot arm 50 moved by the controller 130 to touch the optical sensing devices 120_1, 120_2 can be recorded as the first coordinates

, Second coordinate

, The third coordinate

And the fourth coordinate

, And the linear equation of the sensing beam L1 and the sensing beam L2 and the intersection point I (that is, the calibration coordinates) can be calculated by the following formula (1) to formula (4):

----------------- (1)

---------------- (2)

----------------------------------- (3)

-------------------- (4) Among them, the formula (1) is the linear equation of the sensing beam L1, and the formula (2) is the linear equation of the sensing beam L2 , Formula (3) is the X coordinate of the intersection I of the line, and Formula (4) is the Y coordinate of the intersection I of the line. Therefore, after calculating the coordinate of the connection intersection point by the above formula, the controller 130 rotates the robot arm 50 along the central axis U by 180 degrees, and performs the calibration process again to calculate another coordinate of the connection intersection point by the above formula. Then, according to the coordinates of the intersection point of the two connecting lines to obtain the calibration coordinates, the calibration is completed. In this way, there is no need to additionally mark or configure additional tools on the platform 110, thereby achieving rapid calibration. In some embodiments, the selected rotation angle of the robot arm 50 along the central axis U may also be 90 degrees, 270 degrees, or other angles, and the present invention is not limited thereto.

FIG. 4 is a plan view of a moving path of a robot arm in another embodiment. Referring to FIG. 4, in the calibration method of this embodiment, the controller 130 moves the robot arm 50 around the intersection point I of the two sensing beams L1, L2 to touch the two sensing beams L1, L2, and the touched Multiple different positions B1, B2, B3, B4 are recorded as a set of sensing coordinates. In detail, the controller 130 controls the robot arm 50 to move from position P5 through position P6, position P7, position P8 to position B4, and touches the position B1, position B2, and position B3 of the sensing beams L1, L2 during the movement And the position B4 is recorded as the first coordinate, the second coordinate, the third coordinate, and the fourth coordinate, respectively. In other words, the controller 130 controls the robotic arm 50 to move in a mouth shape from the starting point, so as to successively touch different positions of the two sensing beams L1, L2.

Therefore, the linear equation of the sensing beam L1 emitted by the optical sensing device 120_1 can be calculated by the first coordinate and the third coordinate according to the above formula, and the optical sensing can be calculated by the second coordinate and the fourth coordinate according to the above formula The straight line equation of the sensing beam L2 emitted by the device 120_2, and then calculate the X coordinate of the intersection point I according to the above formula through the two straight line equations. In this way, in addition to the need for additional marking or additional tools on the platform 110 to achieve rapid calibration, the movement path of the robot arm 50 can be further simplified to make the calibration process faster.

FIG. 5 is a flowchart of a calibration method for a robot arm according to an embodiment of the invention. The calibration method of the robot arm 50 of this embodiment can be applied to at least the robot arm calibration system of FIGS. 1 to 4, but the invention is not limited thereto. The following description will take the robotic arm calibration system 100 of FIG. 3 as an example, please refer to FIGS. 3 and 5. In the robotic arm calibration method of this embodiment, first, step S500 is performed to provide a robotic arm calibration system 100, including a platform 110, two sets of optical sensing devices 120 disposed on the platform 110, and a controller electrically connected to the robotic arm 50 130. Next, step S510 is executed to activate two sets of optical sensing devices 120_1 and 120_2 to generate two sensing beams L1 and L2 and form an intersection point I at the calibration point C (see FIG. 2) of the platform 110.

After the above steps, step S520 is executed to control the robot arm 50 to pass through at least two different positions on each sensing beam L1, L2. Next, step S530 is executed to record a set of sensing coordinates (including multiple sensing coordinates) corresponding to the platform 110. Next, after step S530 is executed for the first time, step S540 is executed to control the robot arm 50 to rotate by an angle, and then steps S510 to S530 are repeatedly executed to record another set of corresponding sensing coordinates. Finally, step S550 is executed to calculate the calibration coordinates of the robot arm 50 according to a plurality of sensing coordinates (ie, the two sets of sensing coordinates obtained above).

In the embodiment of FIG. 3, the above step S520 further includes: controlling the robot arm 50 to move from the four different starting points toward the corresponding sensing beams L1, L2 respectively, when the robot arm 50 touches the corresponding sensing beams L1 At L2, the control mechanical arm 50 stops moving. Alternatively, in the embodiment of FIG. 4, the above step S520 further includes: controlling the robot arm 50 to move in a mouth shape from the starting point, so as to successively touch different positions of the two sensing beams L1 and L2.

In summary, in the robot arm calibration system and robot arm calibration method according to the preferred embodiment of the present invention, the robot arm moves through the control of the controller and touches the two sensing beams generated by the two sets of optical sensing devices. At least two different positions, and recorded as a set of sensing coordinates according to the touched position, then after controlling the robot arm to rotate an angle, repeat the above process to record another set of sensing coordinates, and finally based on these two sets of sensing Coordinates to calculate the calibration coordinates of the robot arm. Therefore, no additional marking or additional tools are needed to achieve fast calibration.

Although the present invention has been disclosed as above with examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be subject to the scope defined in the appended patent application.

50‧‧‧Robot 100‧‧‧ Robotic Arm Calibration System 110‧‧‧platform 120, 120_1, 120_2‧‧‧ optical sensing device 130‧‧‧Controller A1, A2, A3, A4, B1, B2, B3, B4, P1, P2, P3, P4, P5, P6, P7, P8 C‧‧‧ Calibration point L, L1, L2‧‧‧sensing beam I‧‧‧Intersection U‧‧‧Central axis S500, S510, S520, S530, S540

FIG. 1 is a schematic side view of a robot arm calibration system and a robot arm according to an embodiment of the invention. FIG. 2 is a schematic top view of the robotic arm correction system of FIG. 1. FIG. 3 is a plan view of the movement path of the robot arm in one embodiment. FIG. 4 is a plan view of a moving path of a robot arm in another embodiment. FIG. 5 is a flowchart of a calibration method for a robot arm according to an embodiment of the invention.

100‧‧‧ Robotic Arm Calibration System

110‧‧‧platform

120_1, 120_2‧‧‧ Optical sensing device

A, A2, A3, A4, P1, P2, P3, P4

L1, L2‧‧‧sensing beam

I‧‧‧Intersection

Claims (10)

A mechanical arm correction system is suitable for correcting a mechanical arm. The mechanical arm correction system includes: platform; Two sets of optical sensing devices are arranged on the platform, and the intersection point of the two sensing beam lines emitted by the two sets of optical sensing devices on the platform orthographic projection overlaps the correction point of the platform; and A controller, electrically connected to the robot arm, adapted to move the robot arm to pass the two sensing beams, wherein the controller controls the robot arm to pass through at least two of each sensing beam To record a set of sensing coordinates corresponding to the platform at different positions, the controller controls the robot arm to rotate an angle and repeat the above process to record another corresponding set of sensing coordinates, and then the controller The two sets of sensing coordinates are calculated to obtain the corrected coordinates of the mechanical arm. The robotic arm calibration system as described in item 1 of the patent application range, wherein the two sensing beams of the two sets of optical sensing devices are perpendicular to each other. The robotic arm calibration system as described in item 1 of the patent application range, wherein the two sets of optical sensing devices are fiber optic sensors, respectively. The robotic arm correction system as described in item 1 of the patent application scope, wherein the controller controls the robotic arm to move from the four different starting points toward the corresponding sensing beam respectively, when the robotic arm touches When corresponding to the sensing beam, the controller controls the mechanical arm to stop moving, and records the corresponding sensing coordinates. The robotic arm correction system as described in item 1 of the patent application scope, wherein the controller controls the robotic arm to move in a mouth shape from a starting point to successively touch different positions of the two sensing beams. A calibration method for a mechanical arm, including: (a) Provide a robotic arm calibration system, including a platform, two sets of optical sensing devices arranged on the platform, and a controller electrically connected to the robotic arm; (b) Activate the two sets of optical sensing devices to generate two sensing beams and form an intersection at the calibration point of the platform; (c) controlling the robot arm to pass through at least two different positions of each of the sensing beams; (d) Record a set of sensing coordinates corresponding to the platform; (e) control the mechanical arm to rotate by an angle; (f) Repeat the above steps (b)~(c); (g) record another set of corresponding sensing coordinates; and (h) Calculate the calibration coordinates of the robot arm based on the two sets of sensing coordinates. The method for calibrating a robotic arm as described in item 6 of the patent application, wherein the two sensing beams of the two sets of optical sensing devices are perpendicular to each other. The method for calibrating a robotic arm as described in item 6 of the patent scope, wherein the two sets of optical sensing devices are optical fiber sensors. The method for correcting a robot arm as described in item 6 of the patent application range, wherein the step of controlling the robot arm to pass through at least two different positions on each of the sensing beams includes: The robotic arm is controlled to move from four different starting points toward the corresponding sensing beam, and when the robotic arm touches the corresponding sensing beam, the robotic arm is controlled to stop moving. The method for correcting a robot arm as described in item 6 of the patent application range, wherein the step of controlling the robot arm to pass through at least two different positions on each of the sensing beams includes: The robotic arm is controlled to move in a mouth shape from the starting point to successively touch different positions of the two sensing beams.

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