KIMM used MATLAB®, Simulink®, and several other products to design, simulate, and implement real-time controllers for the antirolling system and demonstrate a working prototype.
Park converted a SolidWorks assembly of the mobile harbor platform into a Simscape Multibody™ model comprising a one-meter-wide cross-section of a scaled-down version of the catamaran. Park used Simscape Multibody to model the AMD system.
Simulations of the AMD system model enabled Park to determine how much mass would be needed to counteract the catamaran’s motion.
Park developed Simulink models of the maglev and AMD controllers. He then performed closed-loop simulations using the catamaran model to verify the functionality of the control algorithms.
Using Simulink Design Optimization™ and Optimization Toolbox™, Park tuned design parameters, including the speed of the AMD and the size of the linear motor, to improve system performance.
“Simulations in Simulink and Simscape Multibody showed that the mass didn’t need to move as quickly as I had thought, so I revised the specification for the linear motor,” says Park.
Park used a simulation of the optimized design to show managers and stakeholders at KIMM how the system would perform before it was implemented in hardware.
He used Simulink Coder™ to generate C code from the Simulink controller models. He executed the code in real time using Simulink Real-Time™, which ran on a PC/104 computer with an I/O board providing the analog-to-digital and digital-to-analog interface to the prototype catamaran hardware.
Initial experiments showed that the controller for the AMD worked flawlessly. The controller for the maglev required minor adjustments to the gain. After this tuning was complete, the prototype controller successfully stabilized the 118 kg catamaran cross-section using a 4.1 kg mass in about 5 seconds.
Experiments with the prototype showed that it would be difficult to generate enough power to drive the mass required on the planned mobile harbor. However, KIMM researchers also learned that the stabilizing technology worked, opening opportunities to commercialize it for smaller vessels, such as yachts and cranes, and for bipedal walking robots.