Researcher in the Spotlight: Lennart Blanken

Repetitive and learning motion control in printing systems

"Hi, my name is Lennart Blanken and I’m doing a PhD study on repetitive and learning motion control in printing systems within the Control Systems Technology research group of the Mechanical Engineering department."

"Printing systems are subject to increasing requirements regarding accuracy, throughput and cost. Traditional controllers, including feedback and feedforward controllers, are designed before commissioning the system, and remain fixed throughout the lifecycle of the system. The aim of my research is to develop and implement so-called learning controllers that enhance performance by learning from past measured error signals. Indeed, many disturbances are highly repetitive due to batch-to-batch operation, for example, and repeating movements of mechanical components. Exploiting information from the past can thus compensate for these disturbances."

image

Improvements 

"Often in motion systems, the disturbances encountered do not repeat exactly: there might be small variations from repetition to repetition. To guarantee acceptable performance under all circumstances, the robustness of the learning controllers to variations in the disturbances must be improved. In addition, disturbances may occur in many subcomponents of complex printing systems, which may exhibit a substantial amount of interaction. Hence, to effectively improve performance, multivariable learning controllers are required. Such controllers are considerably more difficult to design than controllers with only one input and output."

Experimental validation 

"During the first two and a half years of my PhD I have validated experimentally the techniques developed to industrial printing systems, including the Océ Arizona flatbed printers at both Océ itself and the CST Motion Laboratory at TU/e. The direct aim of my research is to improve the performance of industrial printing systems, in terms of printing accuracy, throughput and cost through the use of advanced learning control techniques. Seen from a broader perspective, also outside of printing, my research contributes to improved manufacturing methods for higher quality products at lower cost."

"On the topic ‘Controlling of Printing Systems’ both Robin de Rozario and I are doing research. Robin is researching a different aspect: the identification and control of position-dependent printing machines. So our work is complementary. We work on different technical and practical aspects, but in the end address the same goals in printing: improved printing performance. We collaborate on an abstract level, discussing new ideas and scientific trends, and present our research findings and outcomes at quarterly progress meetings with Océ staff members and research colleagues from TU/e."