This is not generally done, however, and, for example, the intercept values for mechanical power for the species studied by Cavagna et al. [6], and Heglund et al. [3] were different from zero.
In other words, although our value for mechanical power for staying at the bottom is considerably higher than previous estimates, it is still low enough to account for less than a quarter of the metabolic rate of the dive, leaving ample room for the extra energy spent descending through the water column and losses associated with the conversion of metabolic energy into mechanical energy.
The feedback control is supposed to achieve transient stabilization and voltage regulation when faults occur to the turbines so that the mechanical power may permanently take any (unknown) value within its physical bounds.
The large difference for power reported in the present analysis compared with previous studies stems from the fact that we report total mechanical power exerted in paddling whereas the earlier values refer only to the power output (i.e. the power needed to move the body).
In addition, measured values of the average torque, mechanical power, volumetric flow rate and transient pressure variations in the suction and compression chambers are shown to be in good agreement with theoretical predictions.
The operating conditions are computed online using the above physical available measurements, the terminal voltage reference value and the estimate of the mechanical power input.
Comparing the power available from muscles and the mechanical power required for flight, theoretical studies have predicted that the margin between these values should decrease with body size and that flying animals have a maximum body size [7], [10], [11], [13], [15], [16], [17].
Mechanization refers to the replacement of human (or animal) power with mechanical power of some form.
Animal power and machinery are substituted for human labour; mechanical power then replaces animal power.
The efficiency is the ratio of the electrical power output to the mechanical power input.
