A note on the calculation of the approximate time-of-release for optimal latched-control of wave-power systems

The more promising wave-power devices utilize resonance or resonance-like phenomena in their operation. Budal and Falnes [1] have brought the theory of such devices to prominence and have proposed an intriguing active-control scheme which seeks to keep the velocity of the primary moving part of the device and the wave-force acting on it in-phase, at least over critical periods in the cycle. The device is held stationary as the wave advances until such a time in the cycle that release of the device at this moment will ensure that it reaches its maximum velocity simultaneously with the peak of the wave-force. The precise calculation of the time-of-release involves the solution of nonlinear simultaneous equations. Here we present a simple approximate calculation of this time-of-release and suggest an iterative method of improving the accuracy.