The packaging of pre-packaged meal salads available in supermarkets is currently only partially automated. Apart from the main source of carbohydrates (often some form of pasta or potatoes) and/or lettuce, the ingredients are added by hand. This is done by employees positioned at an assembly line, who take the ingredients from a crate by hand and drop them in the meal. The precision of this method is limited, given the inability of humans to accurately estimate weight. Furthermore, this task is very repetitive and menial, making it difficult for employees to stay focussed and deliver consistent portions of ingredients during the full duration of their shift. To resolve this issue and improve consistency, a research project was started tasked with the direct replacement of these employees with robotic arms without significantly altering the existing production line. One possible solution being investigated is dosing the ingredient using a scoop attached to the end of a robotic arm.
The current setup consists of a 6 DOF UR5 robot arm with a small scoop attached to the final link. Close to this arm, at a fixed position, is a crate of a fixed size and type containing an ingredient such as bell pepper cubes. The robot arm is controlled using ROS2 in combination with MoveIt, which are used for implementing configuration restrictions and path planning. Furthermore, a Zivid camera is used to observe the workspace. The task set for this setup is to consistently take a dose of the ingredient from the crate and dispense it in a target container. A method to achieve this despite variations in the density of the ingredient and the motion constraints of the 6DOF robot arm is needed. Depending on the ingredient distribution in the crate, the most suitable scooping motion must be chosen and executed.
The goal of this assignment is to identify how the desired amount of ingredients can consistently be taken from a sufficiently filled crate and dispensed into a target container using a scoop at the end of a 6DOF robot arm. As part of this investigation, a method to verify whether the scooping motion is needed. Furthermore, damage to the crate, the ingredients in it and the robot arm is to be prevented. To achieve this goal, the scooping motion, the control strategy and the design of the scoop will be investigated.