The ship straight-line tracking system is restricted by a nonintegrable second order nonholonomic constraint,so it has underactuated characteristic and is difficult to control.In this paper,first the control of the ship straight-line tracking was converted to the control of an actuated system by the output variable redefined method.The stabilization of ship straight-line tracking system,which can be ensured by the stabilization of the new system,was proved.Then the nonlinear continuous predictive variable structure control method was used to control the new system.The simulation showed the validity of this method,which can stabilized the course and sideslip synchronal,that is,the stabilization of the ship tracking system.Moreover the control performance was excellent even the system was affected by the parameter uncertainty and disturbance,the results show the strong robustness of this method.
The main objective in animal farms is to achieve a high birth rate and to maximise productive performance in terms of average daily gains and feed efficienc...
To test the validity of multiple component analysis by the concomitant linear least squares (LLS) fit of several significant harmonics, growth hormone (GH) concentrations were determined by radioimmunoassay in plasma obtained at about 3-h intervals during a 24-h sampling span from 54 children of short stature, and 22 children of standard stature. A comparison of circadian parameters obtained by LLS indicates similar characteristics between both groups. Differences were found, however, in a prominent 8-h ultradian component documented for the short, but not the standard-stature children. This procedure of multiple LLS rhythmometry is recommended for the modeling of nonequidistant and/or nonsinusoidal time series, as well as for simultaneous estimation of parameters from several periodic components.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>