A system and method for controlling an internal combustion engine provide valve
actuation that selectively couples an energy storage device to a launching coil
to recover energy stored in the magnetic field and valve spring of the launching
coil, decouples the energy storage device during a valve opening or closing event
to control energy supplied to the catching coil, and couples the energy storage
device to the catching coil to transfer energy from the storage device to the catching
coil to provide a repeatable soft landing. A nonlinear feedback controller incorporates
a feedforward system with an observer to control the rate of energy into the magnetic
field of the catching coil while compensating for system losses and work to overcome
gas forces within the combustion chamber. Feedback linearization techniques improve
stability of the control system.