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  • Author: Hristofor Koev x
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Dimitar Dichev, Hristofor Koev, Totka Bakalova and Petr Louda

Abstract

The present paper considers a new measurement concept of modeling measuring instruments for gyro-free determination of the parameters of moving objects. The proposed approach eliminates the disadvantages of the existing measuring instruments since it is based, on one hand, on a considerably simplified mechanical module, and on the other hand, on the advanced achievements in the area of nanotechnologies, microprocessor and computer equipment. A specific measuring system intended for measuring the trim, heel, roll, and pitch of a ship has been developed in compliance with the basic principles of this concept. The high dynamic accuracy of this measuring system is ensured by an additional measurement channel operating in parallel with the main channel. The operating principle of the additional measurement channel is based on an appropriate correction algorithm using signals from linear MEMS accelerometers. The presented results from the tests carried out by means of stand equipment in the form of a hexapod of six degrees of freedom prove the effectiveness of the proposed measurement concept

Open access

Dimitar Dichev, Hristofor Koev and Petr Louda

Abstract

The present article views a measuring system for determining the parameters of vessels. The system has high measurement accuracy when operating in both static and dynamic mode. It is designed on a gyro-free principle for plotting a vertical. High accuracy of measurement is achieved by using a simplified design of the mechanical module as well by minimizing the instrumental error. A new solution for improving the measurement accuracy in dynamic mode is offered. The approach presented is based on a method where the dynamic error is eliminated in real time, unlike the existing measurement methods and tools where stabilization of the vertical in the inertial space is used. The results obtained from the theoretical experiments, which have been performed on the basis of the developed mathematical model, demonstrate the effectiveness of the suggested measurement approach.

Open access

Dimitar Dichev, Hristofor Koev, Totka Bakalova and Petr Louda

Abstract

The paper presents a new method for building measuring instruments and systems for gyro-free determination of the parameters of moving objects. To illustrate the qualities of this method, a system for measuring the roll, pitch, heel and trim of a ship has been developed on its basis. The main concept of the method is based, on one hand, on a simplified design of the base coordinate system in the main measurement channel so as to reduce the instrumental errors, and, on the other hand, on an additional measurement channel operating in parallel with the main one and whose hardware and software platform makes possible performing algorithms intended to eliminate the dynamic error in real time. In this way, as well as by using suitable adaptive algorithms in the measurement procedures, low-cost measuring systems operating with high accuracy under conditions of inertial effects and whose parameters (intensity and frequency of the maximum in the spectrum) change within a wide range can be implemented.

Open access

Dimitar Dichev, Hristofor Koev, Totka Bakalova and Petr Louda

Abstract

The paper considers an algorithm for increasing the accuracy of measuring systems operating on moving objects. The algorithm is based on the Kalman filter. It aims to provide a high measurement accuracy for the whole range of change of the measured quantity and the interference effects, as well as to eliminate the influence of a number of interference sources, each of which is of secondary importance but their total impact can cause a considerable distortion of the measuring signal. The algorithm is intended for gyro-free measuring systems. It is based on a model of the moving object dynamics. The mathematical model is developed in such a way that it enables to automatically adjust the algorithm parameters depending on the current state of measurement conditions. This makes possible to develop low-cost measuring systems with a high dynamic accuracy. The presented experimental results prove effectiveness of the proposed algorithm in terms of the dynamic accuracy of measuring systems of that type.

Open access

Dimitar Dichev, Hristofor Koev, Totka Bakalova and Petr Louda

Abstract

One of the most complex problems in measuring equipment is related to the provision of the required dynamic accuracy of measuring systems determining the parameters of moving objects. The present paper views an algorithm for improving the dynamic accuracy of such measuring systems. It is based on the Kalman method. The algorithm aims to eliminate the influence of a number of interference sources, each of which is of secondary significance. However, their total effect can cause considerable distortion of the measurement signal. The algorithm model is designed for gyro-free measuring systems. It is based on one of the most widely used elements in the dynamic systems, namely the physical pendulum, due to which measuring systems of high dynamic accuracy and low cost can be developed. The presented experimental results confirm the effectiveness of the proposed algorithm with respect to the dynamic accuracy of measuring systems of this type.