Robotic stacking fly grab method

Abstract

The present application relates to a kind of mechanical hand stacking flight grabbing method, using dynamic grabbing mode, by accurately controlling the movement of mechanical grab, it can be in the process of following the synchronous operation of roller, to the glass plate flowing on production line, fast, stable grabbing.This flight grabbing mode completely gives up the inefficient link that mechanical grab needs to wait for the glass plate to stop in traditional static grabbing mode, realizes the continuous operation of production process, significantly shortens the production tact time of single product.Thereby, the production capacity of production line is directly and substantially improved, the product output in unit time is significantly increased, greatly improves production efficiency.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic glass manufacturing technology, and in particular to a method for stacking and grasping glass using a robotic arm. Background Technology

[0002] In the current technological landscape, with the continuous development of industrial automation technology, more and more industrial robots are being applied to various stages of production and manufacturing to improve production efficiency, reduce labor costs, and improve product quality. In the glass manufacturing industry, especially in the production of large-size, high-volume glass, the handling and stacking of glass sheets is a crucial step.

[0003] To address the problems associated with manual handling and stacking, several automated handling and stacking technologies have been introduced into glass production lines. Existing solutions primarily employ industrial robots for static gripping and stacking, or utilize dedicated roller encoders. The method of using industrial robots for static gripping and stacking typically involves equipping the robot with a suction cup gripper to grasp the glass sheet while it is stationary, then transporting it to a stacking rack. The drawback of this method is that it requires waiting for the glass sheet to stop on the roller conveyor before gripping, reducing the overall efficiency of the production line and failing to meet the demands of high-volume glass production lines. While using dedicated roller encoders to acquire roller speed information and synchronize it with the mechanical gripper control system allows for a degree of dynamic gripping, it requires additional, expensive dedicated encoders, increasing system cost and complexity.

[0004] In summary, existing glass sheet handling and stacking technologies suffer from the following problems: low gripping efficiency, high system cost, poor adaptability to glass sheets and stacking racks, and low degree of automation. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a robotic gripper that can grasp objects while following the movement of rollers, without waiting for the glass plate to stop.

[0006] To achieve the above objectives, the robotic arm stacking and flying grasping method designed in this invention includes the following steps:

[0007] S10. Obtain motion information of the glass plate conveyed by the roller conveyor on the production line. The motion information includes the movement speed of the glass plate, the size information of the glass plate, and the position information of the glass plate. The movement speed of the glass plate is obtained in real time by acquiring the speed of the roller conveyor through an industrial bus. The size information of the glass plate is obtained by pre-input or measurement. The position information of the glass plate is obtained by detecting the leading edge position of the glass plate through photoelectric sensors installed on the roller conveyor.

[0008] S20. When the photoelectric sensor detects the leading edge of the glass plate, the mechanical gripper is controlled to move from the initial position to the pre-grabbing point, and the gripping posture of the mechanical gripper is adjusted. The pre-grabbing point is located above the movement path of the glass plate, and a time margin is reserved for the mechanical gripper to reach the gripping position.

[0009] S30. After the mechanical gripper reaches the pre-grabbing point, it adjusts the speed and position of the mechanical gripper in real time through a PID algorithm based on the obtained speed of the glass plate, so that the mechanical gripper moves synchronously with the glass plate.

[0010] S40. Based on the size information of the glass plate and the position of the glass plate relative to the center of the adsorption plane, determine the gripping position of the glass plate. When the glass plate reaches the gripping position, control the mechanical gripper to descend and adsorb the glass plate. The mechanical gripper is a suction cup gripper with multiple grouped air paths. Based on the size information of the glass plate, control the opening and closing of each air path to adapt to different types of glass plates.

[0011] S50. The mechanical gripper picks up the glass plate and lifts it to the side of the target stack. The planar sensor on the mechanical gripper detects the depth and position of the stack surface of the stack. The mechanical gripper is then adjusted in position and orientation to place the glass plate on the stack.

[0012] S60. After the mechanical gripper releases the glass plate, it returns to the initial position or waiting position, ready for the next gripping and stacking cycle.

[0013] Preferably, in step S30, the specific steps of the PID algorithm include:

[0014] The output signal is set to the control signal U[t] for the movement speed of the mechanical gripper;

[0015] The sampling time is set to t, and the sampling interval is less than or equal to 10ms.

[0016] Set the proportional coefficient to K, the integral coefficient to I, the derivative coefficient to D, the glass plate's moving speed to Vg, and the mechanical gripper's actual moving speed to Vr;

[0017] Let the error be e[t], where e[t] = Vg(t) - Vr(t);

[0018] The control signal U[t] is calculated using the formula: U[t]=K*e[t]+I*Σe(j)+D*(e[t]-e[t-1]), where Σe(j) is the accumulated error value, and the value of j ranges from 0 to t;

[0019] Based on the control signal U[t], the movement speed of the mechanical gripper is controlled so that the speed of the mechanical gripper reaches the same set value as the speed of the glass plate.

[0020] Preferably, in step S40, the control method for the multi-path grouping gas path includes:

[0021] The suction cup is divided into multiple independently controlled air path groups;

[0022] Select the required suction cup assembly based on the dimensions of the glass plate;

[0023] The air passage valve of the selected suction cup group is opened, and the air passage valve of the unselected suction cup group is closed.

[0024] Preferably, in step S50, after the mechanical gripper descends to adsorb and grasp the glass plate, the edge position of the glass plate is detected by multiple edge sensors set on the mechanical gripper to obtain the position of the glass plate relative to the center of the adsorption plane of the mechanical gripper.

[0025] Preferably, the method for determining the pre-grabbing point of the mechanical gripper includes:

[0026] The time required for the glass plate to reach the grasping position is calculated based on the moving speed of the glass plate and the distance of the glass plate from the photoelectric sensor to the grasping position.

[0027] The start time of the mechanical gripper is determined based on the movement time of the mechanical gripper from its initial position to the intended gripping point;

[0028] Allow at least 10% time margin to ensure that the mechanical gripper can reach the ready gripping point in a timely manner.

[0029] Preferably, in step S50, before placing the glass plate on the stack, the method further includes:

[0030] The number of stacking layers for the current glass panels is determined based on the number already stacked.

[0031] Adjust the placement height according to the number of stacking layers.

[0032] The robotic arm stacking and flying gripping method designed in this invention adopts a dynamic gripping mode. By precisely controlling the movement of the robotic gripper, it can quickly and stably grip glass sheets flowing on the production line while moving synchronously with the roller conveyor. This flying gripping method completely eliminates the inefficient step of the traditional static gripping mode where the robotic gripper needs to wait for the glass sheet to stop, realizing continuous operation of the production process and significantly shortening the production cycle time of a single product. As a result, the production line capacity is directly and significantly increased, the product output per unit time is significantly increased, and production efficiency is greatly improved. Attached Figure Description

[0033] Figure 1 This is a flowchart of the robotic arm stacking and flying grasping method provided in the embodiments of this application.

[0034] Figure 2 This is a schematic diagram of the mechanical gripper structure provided in the embodiments of this application.

[0035] Figure 3 This is a schematic diagram of the mechanical gripper speed adjustment provided in the embodiments of this application. Detailed Implementation

[0036] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0037] The robotic arm stacking and flying grasping method described in this embodiment adopts a dynamic grasping mode, which realizes the grasping and stacking of glass plates by the robotic gripper in motion, thereby improving production efficiency, reducing costs, and enhancing adaptability to different glass plates and stacking racks.

[0038] like Figures 1 to 3 As shown, the specific steps include:

[0039] S10. Acquire motion information of the glass plate conveyed by the roller conveyor on the production line. This motion information includes the glass plate's speed, dimensions, and position. The glass plate's speed is obtained in real-time via an industrial bus, acquiring the roller conveyor's speed. The glass plate's dimensions are obtained through pre-input or measurement. The glass plate's position is obtained by detecting the leading edge position of the glass plate using photoelectric sensors (such as through-beam photoelectric switches) mounted on the roller conveyor. This allows for comprehensive acquisition of the glass plate's speed, dimensions, and position information, providing a data foundation for subsequent precise control. Real-time acquisition of the roller conveyor speed via the industrial bus ensures the accuracy and timeliness of the speed information, a prerequisite for precise grasping.

[0040] S20. When the photoelectric sensor detects the leading edge of the glass plate, the mechanical gripper is controlled to move from the initial position to the pre-grabbing point, and the gripping posture of the mechanical gripper is adjusted. The pre-grabbing point is located above the movement path of the glass plate, and a time margin is reserved for the mechanical gripper to reach the gripping position.

[0041] Specifically, when the photoelectric sensor detects the leading edge of the glass plate, the control system immediately triggers the mechanical gripper to move from its standby position (e.g., above the side of the roller conveyor) to above the glass plate, and adjusts the gripper's posture according to the direction of the glass plate's movement to make it parallel to the direction of the glass plate's movement, thus preparing for subsequent following and gripping actions and saving time.

[0042] In one embodiment, the method for determining the pre-grabbing point of the mechanical gripper includes: calculating the time required for the glass plate to reach the gripping position based on the moving speed of the glass plate and the distance of the glass plate from the photoelectric sensor to the gripping position; determining the start time of the mechanical gripper based on the movement time of the mechanical gripper from the initial position to the pre-grabbing point; and reserving a time margin of not less than 10% to ensure that the mechanical gripper can reach the pre-grabbing point in a timely manner.

[0043] Assuming the glass sheet moves at a speed of 1 meter per second on the glass production line, the photoelectric sensor is installed 5 meters away from the gripping position, and it takes 2 seconds for the mechanical gripper to move from the initial position to the ready gripping point.

[0044] Before the production line starts running, parameters such as the glass plate's movement speed (1 m / s), the distance from the photoelectric sensor to the gripping position (5 m), and the movement time of the robotic gripper from its initial position to the pre-grip point (2 seconds) are pre-input into the robotic gripper's control system. The pre-grip point is set to be directly above the glass plate's movement path, 0.2 meters away from the glass plate surface.

[0045] When the leading edge of the glass plate reaches the location of the photoelectric sensor, the photoelectric sensor sends a trigger signal to the control system. Based on the glass plate's speed (1 m / s) and the distance from the photoelectric sensor to the gripping position (5 m), the control system calculates that the time required for the glass plate to reach the gripping position is 5 seconds. Based on the mechanical gripper's movement time from its initial position to the pre-grip point (2 seconds), the control system determines that the mechanical gripper's activation time should be 3 seconds after the photoelectric sensor trigger. Considering the need to reserve at least a 10% time margin, i.e., 0.5 seconds, the actual activation time of the mechanical gripper should be 2.5 seconds after the photoelectric sensor trigger. 2.5 seconds after the electrical sensor triggers, the control system controls the mechanical gripper to start moving from the initial position (e.g., above the side of the roller conveyor). The target position is the pre-grabbing point. At the same time, the mechanical gripper adjusts its posture according to the movement direction of the glass plate (e.g., along the positive X-axis) so that the suction cup plane is parallel to the surface of the glass plate and the movement direction of the gripper is consistent with the movement direction of the glass plate. After 2 seconds of movement, the mechanical gripper reaches the pre-grabbing point and maintains its posture and speed synchronized with the glass plate. At this time, the glass plate is also about to reach the gripping position, thus ensuring the timeliness and reliability of the gripping and avoiding gripping failure caused by the lag in the mechanical gripper's movement.

[0046] S30. After the mechanical gripper reaches the pre-grabbing point, it adjusts the speed and position of the mechanical gripper in real time through a PID algorithm based on the obtained speed of the glass plate, so that the mechanical gripper moves synchronously with the glass plate.

[0047] Specifically, the specific steps of the PID algorithm include:

[0048] The output signal is set to the control signal U[t] for the movement speed of the mechanical gripper;

[0049] The sampling time is set to t, and the sampling interval is less than or equal to 10ms.

[0050] Set the proportional coefficient to K, the integral coefficient to I, the derivative coefficient to D, the glass plate's moving speed to Vg, and the mechanical gripper's actual moving speed to Vr;

[0051] Let the error be e[t], where e[t] = Vg(t) - Vr(t);

[0052] The control signal U[t] is calculated using the formula: U[t]=K*e[t]+I*Σe(j)+D*(e[t]-e[t-1]), where Σe(j) is the accumulated error value, and the value of j ranges from 0 to t;

[0053] Based on the control signal U[t], the movement speed of the mechanical gripper is controlled to reach the same set value as the speed of the glass plate. Thus, during operation, the values ​​of PID parameters K, I, and D can be adjusted in real time according to the actual movement state and speed deviation of the mechanical gripper. For example, if the mechanical gripper's speed response is slow, the value of K can be increased; if the mechanical gripper's speed oscillates, the value of D can be adjusted appropriately; if the steady-state error is large, the value of I can be adjusted appropriately. In other words, by comparing the actual speed of the mechanical gripper and the movement speed of the glass plate in real time, and dynamically adjusting the control signal according to the magnitude, accumulation, and trend of the error, the movement speed of the mechanical gripper can be precisely controlled, ensuring that it always remains synchronized with the glass plate. This dynamic adjustment strategy not only achieves synchronized movement between the mechanical gripper and the glass plate but also ensures the smoothness and reliability of the following process, providing precise position and speed for subsequent gripping actions.

[0054] S40. Based on the size information of the glass plate and the position of the glass plate relative to the center of the adsorption plane, determine the gripping position of the glass plate. When the glass plate reaches the gripping position, control the mechanical gripper to descend and adsorb the glass plate. The mechanical gripper is a suction cup gripper with multiple grouped air paths. Based on the size information of the glass plate, control the opening and closing of each air path to adapt to different types of glass plates.

[0055] In specific implementation, such as Figure 2As shown, the control method for multi-channel grouped air paths includes: dividing the suction cups into multiple independently controlled air path groups 100; selecting the required suction cup group based on the size information of the glass plate; controlling the air path valves of the selected suction cup group to open, and the air path valves of the unselected suction cup group to close. For example, for larger glass plates, all air paths can be opened, allowing all suction cup groups to participate in adsorption, ensuring uniform suction force distribution and avoiding gripping failure or glass plate damage due to insufficient or uneven suction force distribution; while for smaller glass plates, only some air paths can be opened, allowing only some suction cup groups to participate in adsorption, avoiding unnecessary compressed air consumption and reducing energy consumption and production costs.

[0056] S50. The mechanical gripper picks up the glass plate and lifts it to the side of the target stack. The mechanical gripper uses a planar sensor to detect the depth and position of the stack surface, adjusts the position and attitude of the mechanical gripper, and places the glass plate on the stack.

[0057] Specifically, after the robotic gripper picks up the glass sheet, it begins to move the glass sheet to the top of the target stack along a predetermined path. Upon reaching the top of the stack, the planar sensor (e.g., a planar displacement sensor) mounted on the robotic gripper activates. During the descent of the robotic gripper, the control system pre-sets a target indentation value. For example, the robotic gripper should indent 5mm for each layer of glass sheets stacked. The indentation detection process is as follows:

[0058] As the robotic gripper begins its descent, a planar sensor measures the distance between itself and the stack below (or the already stacked glass panels). As the gripper descends, the sensor continuously feeds back the current pressure depth data to the control system. The control system compares this real-time pressure depth data with a preset target pressure depth value (5mm): if the current pressure depth is less than the target value, descent continues; if the current pressure depth equals the target value, descent stops, the glass panel is placed, and the suction cup is released; if the current pressure depth is greater than the target value, descent stops again, and the suction cup is released. In this way, the robotic gripper can precisely control the pressure depth during stacking, ensuring accurate and reliable completion of each stack and preventing scratches.

[0059] In some embodiments, in step S50, such as Figure 2 As shown, after the mechanical gripper descends and adsorbs the glass plate, the edge position of the glass plate is detected by multiple edge sensors 200 (e.g., photoelectric sensors) set on the mechanical gripper, thereby obtaining the position of the glass plate relative to the center of the adsorption plane of the mechanical gripper.

[0060] In practice, the edge detection sensor 200 is mounted on the robotic gripper via X-axis and Y-axis drive mechanisms. This allows for precise detection of the glass plate's edge position relative to the gripper. During subsequent stacking operations, the control system accurately compensates for the gripper's trajectory based on calculated positional deviations (0.05 meters to the right in the X-axis and 0.05 meters downwards in the Y-axis). For example, when the gripper transports the glass plate to the top of the stack for placement, the control system will control the gripper to first move 0.05 meters to the left and then 0.05 meters upwards from its original trajectory before performing the placement action. This ensures that even with deviations during gripping, precise compensation guarantees the glass plate will be accurately placed in the center of the stack, guaranteeing stacking accuracy and quality and preventing misalignment or tilting caused by accumulated deviations.

[0061] S60. After the mechanical gripper releases the glass plate, it returns to the initial position or waiting position, ready for the next gripping and stacking cycle.

[0062] In some embodiments, before placing the glass plate on the stacking rack in step S50, the method further includes: determining the current number of stacking layers of the glass plate based on the already stacked quantity; determining the current number of stacking layers of the glass plate based on the already stacked quantity; and adjusting the placement height based on the number of stacking layers. This step ensures that the mechanical gripper can adjust according to the actual height of the current stacking surface when placing the glass plate, avoiding problems such as collisions and unstable placement caused by excessively high or low placement heights.

[0063] The robotic arm stacking and flying gripping method provided in this embodiment adopts a dynamic gripping mode. By precisely controlling the movement of the robotic gripper, it can quickly and stably grip glass sheets flowing on the production line while moving synchronously with the roller conveyor. This flying gripping method completely eliminates the inefficient step of the traditional static gripping mode where the robotic gripper needs to wait for the glass sheet to stop, realizing continuous operation of the production process and significantly shortening the production cycle time of a single product. As a result, the production line capacity is directly and significantly increased, the product output per unit time is significantly increased, and production efficiency is greatly improved.

[0064] In the description of this invention, it should be noted that the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0065] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0066] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for stacking and grasping objects using a robotic arm, characterized in that, Includes the following steps: S10. Obtain motion information of the glass plate conveyed by the roller conveyor on the production line. The motion information includes the movement speed of the glass plate, the size information of the glass plate, and the position information of the glass plate. The movement speed of the glass plate is obtained in real time by acquiring the speed of the roller conveyor through an industrial bus. The size information of the glass plate is obtained by pre-input or measurement. The position information of the glass plate is obtained by detecting the leading edge position of the glass plate through photoelectric sensors installed on the roller conveyor. S20. When the photoelectric sensor detects the leading edge of the glass plate, the mechanical gripper is controlled to move from the initial position to the pre-grabbing point, and the gripping posture of the mechanical gripper is adjusted. The pre-grabbing point is located above the movement path of the glass plate, and a time margin is reserved for the mechanical gripper to reach the gripping position. S30. After the mechanical gripper reaches the pre-grabbing point, it adjusts the speed and position of the mechanical gripper in real time through a PID algorithm based on the obtained speed of the glass plate, so that the mechanical gripper moves synchronously with the glass plate. S40. Control the mechanical gripper to descend and adsorb the glass plate; the mechanical gripper is a suction cup gripper, which has multiple grouped air paths, and controls the opening and closing of each air path according to the size information of the glass plate to adapt to glass plates of different shapes. S50. The mechanical gripper picks up the glass plate and lifts it to the side of the target stack. The planar sensor on the mechanical gripper detects the depth and position of the stack surface of the stack. The mechanical gripper is then adjusted in position and orientation to place the glass plate on the stack. S60. After the mechanical gripper releases the glass plate, it returns to the initial position or waiting position, ready for the next gripping and stacking cycle; In step S30, the specific steps of the PID algorithm include: The output signal is set to the control signal U[t] for the movement speed of the mechanical gripper; The sampling time is set to t, and the sampling interval is less than or equal to 10ms. Set the proportional coefficient to K, the integral coefficient to I, the derivative coefficient to D, the glass plate's moving speed to Vg, and the mechanical gripper's actual moving speed to Vr; Let the error be e[t], where e[t] = Vg(t) - Vr(t); The control signal U[t] is calculated using the formula: U[t] = K*e[t] + I*Σe(j) + D*(e[t] - e[t-1]), where Σe(j) is the accumulated error value, and the value of j ranges from 0 to t; Based on the control signal U[t], the movement speed of the mechanical gripper is controlled so that the speed of the mechanical gripper reaches the same set value as the speed of the glass plate; The method for determining the pre-grabbing point of the mechanical gripper includes: The time required for the glass plate to reach the grasping position is calculated based on the moving speed of the glass plate and the distance of the glass plate from the photoelectric sensor to the grasping position. The start time of the mechanical gripper is determined based on the movement time of the mechanical gripper from its initial position to the intended gripping point; Allow at least 10% of the time margin to ensure that the mechanical gripper can reach the ready gripping point in a timely manner.

2. The robotic arm stacking and flying grasping method according to claim 1, characterized in that, In step S40, the control method for the multi-path grouping gas path includes: The suction cup is divided into multiple independently controlled air path groups; Select the required suction cup assembly based on the dimensions of the glass plate; The air passage valve for the selected suction cup group is opened, while the air passage valve for the unselected suction cup group is closed.

3. The robotic arm stacking and flying grasping method according to claim 1, characterized in that, In step S50, after the mechanical gripper descends and adsorbs the glass plate, the edge position of the glass plate is detected by multiple edge sensors set on the mechanical gripper to obtain the position of the glass plate relative to the center of the adsorption plane of the mechanical gripper.

4. The robotic arm stacking and flying grasping method according to claim 1, characterized in that, In step S50, before placing the glass plate on the stack, the following steps are also included: The number of stacking layers for the current glass panels is determined based on the number already stacked. Adjust the placement height according to the number of stacking layers.

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