Dynamically Controlled Vacuum Level for Vacuum Pad Grippers

Sammanfattning: Vacuum grippers are widely used in the industry where objects needs to be gripped and moved. There is a need to reduce the consumption of compressed air that is used to create vacuum. This project aims to investigate one method to reduce this. A system where the vacuum level is dynamically controlled is proposed to reduce the compressed air consumption during the lift. The acceleration of the object during the lift is used to calculate the vacuum level required to hold onto the object, ensuring that the vacuum level remains at its minimum value during the lift. A valve system that can control the vacuum level dynamically was designed. This consisted of a stepper motor connected to a valve, which takes readings from a vacuum sensor to form a closed loop system that controls the vacuum level. A Fanuc robot was used to do lifts on certain objects. Acceleration data was gathered from these lifts and used to calculate the necessary vacuum level. This array of vacuum values to be used during the lift was sent to the control system and an external system measured the consumed air during the lift. The comparison in air consumption was done for these dynamic vacuum values and a constant vacuum value which is set to the lowest constant value needed to hold onto the object during the lift. The testing to determine the air consumption was first done using the calculated reference vacuum but without the robot to determine how well the system performed. These comparisons showed that the reduction of compressed air consumption was between 19.5% - 29.0% when testing without the robot. A single test case was chosen for testing with the robot and the air consumption reduction in this case was 11.3%