Vacuum chuck vacuum degree control method

Abstract

The invention relates to a method for controlling the vacuum degree of a vacuum chuck. The method comprises the following specific steps: calculating and storing a vacuum degree value SP; the vacuum suction cup is started before the materials are sucked, and the initial output power of the vacuum suction cup is controlled to be 10%-30%; the vacuum degree in the suction cup is detected, and when it is detected that the vacuum degree in the suction cup is in a continuous rising trend, the output power of the vacuum suction cup is increased to the full-load power; when the vacuum degree in the suction cup reaches 95% of the vacuum degree value SP, the output power of the vacuum suction cup is reduced to 80%, and then a PID control algorithm is called to adjust the vacuum degree of the vacuum suction cup; and after the vacuum suction cup conveys the materials in place, the PID control algorithm is quitted, the output power of the empty suction cup is reduced to 10%-30%, after the exhaust valve is opened, the output power of the vacuum suction cup is reduced to 5%, and the vacuum suction cup is separated from the materials until the air pressure sensor detects that the vacuum degree is zero. The technical problem that a conventional vacuum suction cup control method is low in adsorption efficiency is solved.

Description

Technical Field

[0001] This invention belongs to the field of operational transportation technology, specifically relating to a vacuum suction cup vacuum degree control method. Background Technology

[0002] Vacuum suction cups are widely used in today's increasingly automated world. Through vacuum adsorption, they can adsorb, extract, and transfer materials on flat, sheet-like surfaces. Vacuum suction cups are typically attached to a robotic arm, which moves the suction cup to transfer the material. The commonly used adsorption process involves the robotic arm pressing the vacuum suction cup against the material. Then, the suction cup's power unit is activated to create a vacuum inside the suction cup, generating negative pressure. Once the negative pressure reaches a certain value, the robotic arm lifts the suction cup and the material, holding the material at the target location. Afterward, the power unit is turned off, and the pressure relief valve is opened, allowing the negative pressure inside the suction cup to return to positive, detaching the suction cup from the material. This process is then repeated to pick up other materials.

[0003] In the initial stage of material adsorption, the vacuum suction cup is activated based on the signal from the robotic arm's descent, which prolongs the activation waiting time and reduces its efficiency. Furthermore, the constant starting and stopping of the vacuum suction cup's power unit can generate vibrations, especially during material adsorption. Sudden starts and vibrations can cause impact damage to delicate materials. Therefore, it is necessary to provide a vacuum control method for the vacuum suction cup to address these technical problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a vacuum degree control method for a vacuum suction cup, which solves the technical problems of low adsorption efficiency and easy vibration in the early stage of material suction that can cause impact damage to the material.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a vacuum suction cup vacuum degree control method, comprising the following specific steps: S1. Calculate and store the vacuum value SP based on the theoretical weight of the absorbed material, the adsorption area, and the safety factor; S2. Before picking up materials, start the vacuum suction cup. The controller controls the power unit of the vacuum suction cup to make initial output. The initial output power is 10% to 30% of the full load power of the power unit. S3. Use the air pressure sensor on the suction cup to detect the vacuum level inside the suction cup. When the vacuum level inside the suction cup is detected to be continuously increasing, the controller gradually increases the output power of the power device of the vacuum suction cup to the full load power. Otherwise, maintain the state of step S2. S4. When the air pressure sensor detects that the vacuum degree inside the suction cup reaches 95% of the vacuum degree value SP calculated in S1, the controller reduces the output power of the vacuum suction cup's power unit to 80% of the full load power, and then calls the PID control algorithm to adjust the vacuum degree of the vacuum suction cup with the vacuum degree value SP as the adjustment target.

[0006] S5. After the vacuum suction cup delivers the material to the designated location, the PID control algorithm is exited. The controller controls the output power of the vacuum suction cup's power unit to decrease to 10%~30% of the full load power. After opening the vacuum suction cup's exhaust valve, the controller further controls the output power of the vacuum suction cup's power unit to decrease to 5% of the full load power until the pressure sensor detects a vacuum of 0. Then, the controller waits for the vacuum suction cup to separate from the material and restores the output power of the vacuum suction cup's power unit to 10%~30% of the full load power after the vacuum suction cup's exhaust valve is closed. The exhaust efficiency of the exhaust valve is greater than the vacuuming efficiency of the vacuum suction cup's power unit when the output power is 5% of the full load power.

[0007] As a preferred solution, during the material suction and lifting process, the material is weighed, the vacuum value is recalculated based on the actual weight of the material, and the original vacuum value SP is corrected based on the new vacuum value. The PID control algorithm intermittently retrieves the latest vacuum value SP.

[0008] As a preferred approach, when correcting the original vacuum value SP, the original vacuum value SP is corrected stepwise with a correction step of 2%. When the difference between the new vacuum value and the original vacuum value is less than 2%, the new vacuum value directly replaces the original vacuum value SP.

[0009] As a preferred solution, a tension sensor connected between the robotic arm and the vacuum suction cup is used to weigh the material, and the controller reads the average value of the three most recent peak tension values ​​detected by the tension sensor during the uniform lifting phase of the robotic arm.

[0010] The beneficial effects of this invention are as follows: By activating the vacuum suction cup before suctioning the material, and using a pressure sensor on the suction cup to detect the vacuum level inside the suction cup to determine the contact relationship between the vacuum suction cup and the material, this detection method can provide faster feedback to the controller and enable the controller to increase the output power of the vacuum suction cup power unit, allowing the vacuum suction cup to quickly adsorb the material, thus improving the efficiency of material adsorption. Before adsorbing the material, the vacuum suction cup operates at a low power, consuming less energy, but avoiding the vibration and impact caused by activating the vacuum suction cup power unit after the vacuum suction cup comes into contact with the material, thereby improving the safety of the material during the vacuum adsorption process. Detailed Implementation

[0011] The specific embodiments of the present invention are described in detail below.

[0012] A method for controlling the vacuum level of a vacuum chuck includes the following specific steps: S1. Calculate and store the vacuum value SP based on the theoretical weight of the material being absorbed, the adsorption area, and the safety factor. The specific calculation method is: SP = 10FT / S, where F is the weight of the material, T is the safety factor, and S is the area of ​​the suction cup. This calculation method is common knowledge and can be obtained by those skilled in the art through online resources.

[0013] S2. Before suctioning materials, start the vacuum suction cup. The controller controls the power unit of the vacuum suction cup to make initial output. The initial output power is 10% to 30% of the full load power of the power unit; preferably 10% to reduce energy consumption. The initial output power needs to be adjusted according to the area of ​​the suction cup. When the suction cup area is larger, the initial output power will also be increased accordingly.

[0014] S3. Use the air pressure sensor on the suction cup to detect the vacuum level inside the suction cup. When the vacuum level inside the suction cup is detected to be continuously increasing, the controller gradually increases the output power of the power device of the vacuum suction cup to the full load power. Otherwise, maintain the state of step S2. When the suction cup is very close to the material, the air leakage caused by the gap between the suction cup and the material is less than the suction capacity of the vacuum suction cup's power unit, and the vacuum degree inside the suction cup begins to rise. When the suction cup comes into contact with the material, the vacuum degree inside the suction cup will rise rapidly. At this time, gradually increasing the output power of the vacuum suction cup's power unit will not produce vibration or damage to the workpiece. Moreover, the vacuum suction cup can quickly increase the vacuum value to a range that can lift the material, enabling the robotic arm to quickly lift the material for transfer, thereby improving the efficiency of the vacuum suction cup in picking up materials.

[0015] S4. When the air pressure sensor detects that the vacuum degree inside the suction cup reaches 95% of the vacuum degree value SP calculated in S1, the controller reduces the output power of the vacuum suction cup's power unit to 80% of the full load power, and then calls the PID control algorithm to adjust the vacuum degree of the vacuum suction cup with the vacuum degree value SP as the adjustment target.

[0016] PID control algorithm is widely used in the field of vacuum suction cups. Since PID control algorithm is a mature control method, it will not be elaborated on in this embodiment.

[0017] S5. After the vacuum suction cup delivers the material to the designated location, the PID control algorithm is exited. The controller controls the output power of the vacuum suction cup's power unit to decrease to 10%~30% of the full load power. After opening the vacuum suction cup's exhaust valve, the controller further controls the output power of the vacuum suction cup's power unit to decrease to 5% of the full load power until the pressure sensor detects a vacuum of 0. Then, the controller waits for the vacuum suction cup to separate from the material and restores the output power of the vacuum suction cup's power unit to 10%~30% of the full load power after the vacuum suction cup's exhaust valve is closed. The exhaust efficiency of the exhaust valve is greater than the vacuuming efficiency of the vacuum suction cup's power unit when the output power is 5% of the full load power.

[0018] To determine whether the vacuum suction cup has delivered the material to the correct position, a tension sensor is installed between the vacuum suction cup and the robotic arm. When the tension sensor changes from a high tension state to a low tension state until the tension reaches zero or enters a preset range, it indicates that the material has been delivered to the correct position. When the tension sensor changes from a low tension state to a high tension state, it indicates that the material has been lifted. The controller can determine whether the vacuum suction cup has delivered the material to the correct position based on the signal changes from the tension sensor and decide whether to exit the PID control algorithm.

[0019] In this preferred embodiment, during the material suction and lifting process, a tension sensor connected between the robotic arm and the vacuum suction cup is used to weigh the material. The vacuum level is recalculated based on the actual weight of the material, and the original vacuum level value SP is corrected according to the new vacuum level value. The PID control algorithm intermittently retrieves the latest vacuum level value SP during operation. This allows the vacuum suction cup to adaptively suction materials of different weights, thereby improving energy efficiency.

[0020] For example, when the material is relatively light and the original vacuum value SP is set too high, if SP is not corrected, the entire adsorption process will waste energy. After correcting the original vacuum value SP, the controller can reduce the output power of the vacuum suction cup's power unit, thereby achieving energy saving.

[0021] When the material is relatively heavy, the tension sensor will detect a tension that exceeds the theoretical weight of the material when the vacuum suction cup lifts it. At this time, the calculated actual vacuum value SP will be greater than the original vacuum value SP. The result calculated by the PID control algorithm will guide the controller to control the power unit of the vacuum suction cup to increase the output power, thereby improving the pumping efficiency of the vacuum suction cup and ensuring that the vacuum degree of the vacuum suction cup meets the requirements for lifting the material.

[0022] When the material is being lifted at a constant speed, the controller reads the average of the three most recent regularly occurring peak tension values ​​detected by the tension sensor as the material weight. This is to address any localized, regular up-and-down swaying that may occur after the material is lifted. When the material experiences localized up-and-down swaying, the required vacuum level of the vacuum suction cup also fluctuates. Using the average of the three regularly occurring peak tension values ​​as the material weight ensures reliable material suction by the vacuum suction cup. In this embodiment, "regular occurrence" means that the time interval between peak tension values ​​is approximately equal, and the time difference between two adjacent peak tension values ​​does not exceed a preset range, such as 0.5 seconds.

[0023] By employing the above methods to correct the vacuum value SP, the self-adaptability and energy-saving effect of the vacuum chuck can be improved.

[0024] When correcting the original vacuum value SP, in order to eliminate sudden changes in the output power of the vacuum chuck power unit, it is preferable to correct the original vacuum value SP in steps with a correction step of 2%. When the difference between the new vacuum value and the original vacuum value is less than 2%, the new vacuum value directly replaces the original vacuum value SP. The time interval between each correction is equal to the time interval at which the PID control algorithm intermittently retrieves the latest vacuum value SP.

[0025] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some examples of its application, and are not intended to limit the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention.

Claims

1. A method for controlling the vacuum level of a vacuum chuck, characterized in that, The specific steps include the following: S1. Calculate and store the vacuum value SP based on the theoretical weight of the absorbed material, the adsorption area, and the safety factor; S2. Before picking up materials, start the vacuum suction cup. The controller controls the power unit of the vacuum suction cup to make initial output. The initial output power is 10% to 30% of the full load power of the power unit. S3. Use the air pressure sensor on the suction cup to detect the vacuum level inside the suction cup. When the vacuum level inside the suction cup is detected to be continuously increasing, the controller gradually increases the output power of the power device of the vacuum suction cup to the full load power. Otherwise, maintain the state of step S2. S4. When the air pressure sensor detects that the vacuum degree inside the suction cup reaches 95% of the vacuum degree value SP calculated in S1, the controller reduces the output power of the vacuum suction cup's power unit to 80% of the full load power, and then calls the PID control algorithm to adjust the vacuum degree of the vacuum suction cup with the vacuum degree value SP as the adjustment target. S5. After the vacuum suction cup delivers the material to the designated location, the PID control algorithm is exited. The controller controls the output power of the vacuum suction cup's power unit to decrease to 10%~30% of the full load power. After opening the vacuum suction cup's exhaust valve, the controller further controls the output power of the vacuum suction cup's power unit to decrease to 5% of the full load power until the pressure sensor detects a vacuum of 0. Then, the controller waits for the vacuum suction cup to separate from the material and restores the output power of the vacuum suction cup's power unit to 10%~30% of the full load power after the vacuum suction cup's exhaust valve is closed. The exhaust efficiency of the exhaust valve is greater than the vacuuming efficiency of the vacuum suction cup's power unit when the output power is 5% of the full load power.

2. The vacuum degree control method for a vacuum chuck according to claim 1, characterized in that, During the material intake and lifting process, the material is weighed, and the vacuum value is recalculated based on the actual weight of the material. The original vacuum value SP is then corrected based on the new vacuum value. The PID control algorithm intermittently retrieves the latest vacuum value SP.

3. The vacuum degree control method for a vacuum chuck according to claim 2, characterized in that, When correcting the original vacuum value SP, the original vacuum value SP is corrected step by step with a correction step of 2%. When the difference between the new vacuum value and the original vacuum value is less than 2%, the new vacuum value directly replaces the original vacuum value SP.

4. The vacuum degree control method for a vacuum chuck according to claim 2, characterized in that, The material is weighed using a tension sensor connected between the robotic arm and the vacuum suction cup. The controller reads the average of the three most recent peak tension values ​​detected by the tension sensor during the uniform lifting phase of the robotic arm.