96 A Survey of Iterative Learning Control Al earning-based method for high-performance tracking control

The inkjet printing process involves a chain of processes in many physical domains at different length and time scales. The final goal is the deposition of droplets of all kinds of fluids with any desired volume and velocity. To comply with the increasing and diverging requirements for today's inkjet technology, a fundamental understanding of the underlying processes is very important. By combining state of the art experimental and numerical techniques, the physics behind the chain of processes are being explored. The fundamental knowledge gained is crucial for the further development of the inkjet printing technology which became mature in graphical printing applications and plays a key role in many emerging new industrial and medical applications.

Drop dynamics in the inkjet printing process

Iterative learning control (ILC) approaches often exhibit poor extrapolation properties with respect to exogenous signals, such as setpoint variations. This brief introduces rational basis functions in ILC. Such rational basis functions have the potential to both increase performance and enhance the extrapolation properties. The key difficulty that is associated with these rational basis functions lies in a significantly more complex optimization problem when compared with using preexisting polynomial basis functions. In this brief, a new iterative optimization algorithm is proposed that enables the use of rational basis functions in ILC for single-input single-output systems. An experimental case study confirms the advantages of rational basis functions compared with preexisting results, as well as the effectiveness of the proposed iterative algorithm.

/pdf/rational-basis-functions-in-iterative-learning-control-with-4q3g4sefc6.pdf

Rational Basis Functions in Iterative Learning Control—With Experimental Verification on a Motion System

https://pure.tue.nl/ws/files/77792274/Mech2017_v7.pdf

On inversion-based approaches for feedforward and ILC

A high-speed waveform design method for piezo inkjet printing is proposed. This method uses the pressure wave information inside the ink dispenser. The pressure wave inside the inkjet dispenser can be effectively measured from the piezo current because the piezo has the self-sensing capability. The measured pressure wave was compared with the dispenser vibration measured by the laser Doppler vibrometer. For high-speed inkjet printing, a two-pulse waveform was designed based on the measured pressure wave to effectively suppress the residual pressure wave after jetting.

A waveform design method for high-speed inkjet printing based on self-sensing measurement

https://pure.tue.nl/ws/files/3753406/706519241335444.pdf

Using iterative learning control with basis functions to compensate medium deformation in a wide-format inkjet printer

https://pure.tue.nl/ws/files/98789606/REILC_aut.pdf

Resource-efficient ILC for LTI/LTV systems through LQ tracking and stable inversion: enabling large feedforward tasks on a position-dependent printer

Advanced control methods potentially enable performance improvements in printing systems for minor additional costs. The aim of this paper is to develop a control framework that is capable of delivering throughput and accuracy enhancements for an industrial flatbed inkjet printer. The proposed method involves iterative learning control with a rational feedforward parameterization to enable varying position references which are required for printing. Experimental results highlight the efficacy of the proposed method in a comparison with related pre-existing learning control approaches.

/pdf/enhancing-flatbed-printer-accuracy-and-throughput-optimal-57kmd7ot3j.pdf

Enhancing Flatbed Printer Accuracy and Throughput: Optimal Rational Feedforward Controller Tuning Via Iterative Learning Control

The printing quality delivered by a Drop-on-Demand (DoD) piezo inkjet printhead is limited mainly due to the residual oscillations in the ink channel. The maximal jetting frequency of a DoD inkjet printhead can be increased by quickly damping the residual oscillations and thus bringing an ink channel to rest after jetting an ink drop. In this paper, we propose a robust optimization-based method to design the input actuation waveform for the piezo actuator in order to improve the damping of the residual oscillations in the presence of parametric uncertainties in the ink-channel model. The proposed method obtains a robust actuation pulse by minimizing the tracking error under the parametric uncertainty. Experimental results with a small-droplet DoD inkjet printhead are presented to show the efficacy of the proposed method and the significant improvement in the ink drop consistency.

A Waveform Design Method for a Piezo Inkjet Printhead Based on Robust Feedforward Control

https://pure.tue.nl/ws/files/91160876/Poster_LBlanken_IFAC_Mech16_v2_centered.pdf

Sjirk Koekebakker

Papers

Using iterative learning control with basis functions to compensate medium deformation in a wide-format inkjet printer

Resource-efficient ILC for LTI/LTV systems through LQ tracking and stable inversion: enabling large feedforward tasks on a position-dependent printer

Enhancing Flatbed Printer Accuracy and Throughput: Optimal Rational Feedforward Controller Tuning Via Iterative Learning Control

A Waveform Design Method for a Piezo Inkjet Printhead Based on Robust Feedforward Control

Design techniques for multivariable ILC:application to an industrial flatbed printer