Camless internal combustion engines offer improvements over traditional engines in terms of torque performance, reduction of emissions, reduction of pumping losses and fuel economy. Theoretically, electromagnetic valve actuators offer the highest potentials for improving efficiency due to their control flexibility. For real applications, however, the valve actuators developed so far suffer from high power consumption and other control problems. One key point for the control is the design of the reference trajectory to be tracked by the closed loop controller. In this paper an optimal trajectory design technique aimed at minimizing power consumption is proposed. An optimization problem that explicitly considers the physical constraints of the system is formulated and a suboptimal solution is derived by exploiting local flatness of the system.