The LIP Automation AG implemented a vision-based assembly system. Previous solutions using mechanical part feeding, which pre-position the product and thus specify the exact position and orientation of the product for the automation unit, or precisely define it for the robot, are very cost-intensive and not very flexible. Chaotic part feeding, determination of the part position via a vision system, and transfer of the PIC position (pick-up position of the component by the robot) to a robot system are cost-effective and very flexible. As a rule, product adaptations can be supplemented at will via parameterization settings. The prerequisite is a reliable image recognition software.
One possible solution is the fully automatic connecting rod and eccentric press system of a globally active precision pump manufacturer in Central Switzerland. In this plant, three linear conveyors are installed in parallel and each one is monitored with a camera system, being controlled by the installed machine vision software MVTec HALCON.
HALCON controls each individual linear conveyor from the vision application and triggers the following actions:
- optimal number of products in the image recognition area – action: start / stop feeding
- optimal positional distribution of the products – action: start / stop flipping
- number of identified products is given – action: start / stop iteration of conveyor algorithm
- product identification – action: error message wrong product supplied
- collision-free accessibility of the robot gripper verified – action: start / stop picking process
The images supplied by the vision cameras are fully evaluated by HALCON. The machine vision software identifies the workpiece, determines the position and orientation, and also calculates the resulting coordinate system of the workpiece. This improved evaluation is performed for all products in the image window. Subsequently, a further evaluation for the optimum removal position is carried out, taking the applications mounted on the robot gripper into account. Robot and gripper geometry are checked for collision with the conveyor system as well as for collision with other parts in the respective environment. Only then the robot will securely pick up the workpiece for the assembly.
The plant is consistently equipped with high-quality components that meet the requirements for high machine availability. Gripper components from Schunk GmbH & Co. KG Spann- und Greiftechnik meet these requirements and increase the customer benefit due to the versatile modular system. More than 40 different variants of connecting rod and eccentric combinations are manufactured in multiple-shift operation. The average changeover time is less than two minutes. This can only be achieved if no manual tool changes, parameterization, or calibration processes are required. The automation system has been designed so that once the operator has activated the job with a barcode reader, the set-up and calibration processes are fully automatically adapted to the given part specifications. This allows the operator to concentrate fully on the production job.