Coordinated control algorithm for condeps of long towed streamer array for geological surveys
Object and purpose of research. This paper studies control system of long streamer array for geological surveys, towed in its typical operational conditions, i.e. at straight course, and scanning the seabed. The purpose is to develop an efficient algorithm for coordinated control over the whole totality of the array's constant-depth control modules (condeps) to ensure its movement within specified depth range. Materials and methods. Taking into account physical peculiarities of geological-survey streamer behavior in its operational conditions, dynamic equations of long lines are linearized, so as to develop the mathematical model of an array consisting of a number of condeps, and then, after the structure of exciting forces is analysed, insignificant components of excitation are neglected. The remaining, significant, components of exciting forces are taken into account in development of coordinated control algorithm for the array's condeps, based on numerical solution of a number of non-linear boundary problems for each section of the array between condeps, as well as based on required controlling forces determined for all condeps taking into account variable full-scale conditions. Main results. This study yielded and justified an efficient algorithm for coordinated condep control of geological-survey streamer array, solving the problem of condep movement in operational conditions at specified depth range taking into account key exciting factors. A typical peculiarity of this algorithm is mitigation of power demand for streamer condep batteries. Conclusion. Theoretical studies performed during this work made it possible to develop a correct mathematical model for dynamics of geological-survey streamer array with a number of condeps, and based on this model, coordinated control algorithm for all these condeps has been developed. The variant of the control algorithm discussed in this paper implies that automatic control system must be located aboard the towing ship and must handle the whole streamer of the array. This system would be convenient for practical implementation and would not require a complex multi-factor control signal for its operation.