Generally, Agfa’s :Dotrix Modular inkjet printer did a good job delivering full-color images quickly. However, when the company decided that it wanted a machine with higher color repeatability and better precision,it turned to the Centre for Concepts in Mechatronics (CCM) to design a custom controller that would achieve the goal, while keeping development time and implementation costs low.

“With Model-Based Design, we saw development time reduction, cost savings, and improved time-to-market,” reported Arend-Jan Beltman, CCM
mechatronics manager and CTO. “Automatic code generation saves time. In addition, we can simply change the model to update our design and we know it will be implemented as required. Our design iterations, from making changes to hardware testing, are completed in five minutes.”

Prior to the project, the existing device’s print-encoder roll that triggered the firing mechanism of ink droplets from four feet away from the inkjet head was problematic. During the printing process, tension on the substrate caused it to stretch which, in turn, caused misalignment of the ink and, ultimately, reduced printing precision. Further operators were unable to tune the printers to avoid these problems.

Knowing these substrate variables, the CCM engineers decided to design a three-loop-based control system. This configuration would allow operators to rapidly calibrate the machine’s control parameters for any printing material. To accomplish their goals, the team used several MathWorks software packages including Simulink, Real-Time Workshop, xPC Target, Signal Processing Toolbox, Control System Toolbox, MATLAB, MATLAB Compiler, and xPC Target Embedded Option.

Other project activities included generating C code that was tested on a real-time prototype using dSPACE hardware. Following the development cycle, the team tested the device on a prototype machine, made refinements, and automatically generated code for further design evaluation. Later, the team deployed the embedded system on PC hardware for production use. This step enabled them to port the validated design to the hardware without translating the code by hand. A graphical user interface (GUI) was created that helps printer operators tune the machines for any substrate. The CCM control system was successfully deployed on existing :Dotrix Modular printers.

MathWorks
www.mathworks.com

Centre for Concepts in Mechatronics
www.ccm.nl

::Design World::