A Comparative and Experimental Study on Gradient and Genetic Optimization Algorithms for Parameter Identification of Linear MIMO Models of a Drilling Vessel

The paper presents algorithms for parameter identification of linear vessel models being in force for the current operating point of a ship. Advantages and disadvantages of gradient and genetic algorithms in identifying the model parameters are discussed. The study is supported by presentation of identification results for a nonlinear model of a drilling vessel.

Probing the NASA Generic Transport Aircraft in Real-Time for Health Monitoring

This brief paper describes the development of a pulse compression probing algorithm for real-time monitoring of nonlinear dynamic systems. The probing outputs of a system being monitored are estimates of the sequences of Markov parameters at the current operating point. By imposing signal to noise ratios at both the controlled outputs and the probing outputs, the probing inputs are designed to be non-intrusive and with the intention that the resulting probing outputs are unaffected by other applied signals to the system. The probing algorithm is implemented on a Virtex-5 field-programmable gate-array evaluation platform to expedite real-time processing, and is applied to monitoring the health of the NASA Generic Transport Aircraft Model (GTM). Samples of probing output residuals are evaluated using the Hotelling'sT2-test for change detection when significant noise is present in the system. This brief paper focuses its discussion on the method of rapid collection of independent samples to reduce detection delay.

Modal Control of an Electrohydrostatic Flight Simulator Motion System

Valve-controlled electro-hydraulic actuators in a Stewart platform configuration have become established as a good way of meeting the performance required for flight simulator motion systems. However, valve-controlled actuators are very inefficient, and thus an electrohydrostatic motion system, controlled using servomotor driven pumps, has been developed by Thales, and is now in production. This paper presents a simulation study of a multi-axis controller which can improve the dynamic response of the new motion system. A modal control approach is used — i.e. the modes of vibration of the system are controlled individually. These modes are dependent on the inertial properties of the platform and the compliance of the actuators. The modes change as the motion system moves throughout its workspace, and so the controller has to adapt to the current operating point. Simulation results are presented based on a partially validated model of the motion system.