Krzysztof Augustynek

On multivariate method of qualitative analysis of Hodgkin-Huxley model with decision tree induction

This paper presents a data mining technique for qualitative analysis of Hodgkin-Huxley model of cell excitability. Such problem cannot be solved analytically. Therefore we apply Monte-Carlo techniques for the generation of model parameters, and use data mining algorithm for classification of learning tuples obtained. As a result we attain a decision tree capable of classifying the excitability depending on the relationship between initial conditions and between rate constants. Details of software development and issues of computational complexity are presented. The software includes the package of Java-classes. An example for classification of excitability of three types is presented.

Dynamic optimisation of articulated vehicle motion for control of stability in critical situation

In the case of unforeseen obstacles, the nominal trajectory of articulated vehicle has to be modified, in order to avoid collisions. The paper presents comparison of dynamic optimisation methods used to calculate optimal braking torques applied to wheels of an articulated vehicle in lane following/changing manoeuvre in order to prevent vehicle before rollover. Gradient, gradientless and evolutionary methods have been employed in order to solve dynamic optimisation problem. The aim of the optimisation is to calculate appropriate braking torques for each wheel in order to restore stability of an articulated vehicle. Calculation of the objective function requires integration of the equations describing the motion of the vehicle. In the paper results obtained from different dynamic optimisation methods have been presented and compared.

An Application of Neural Networks to Control Stability of an Articulated Vehicle in Real Time

The paper presents an application of neural networks to control braking torques on wheels of an articulated vehicle in an untripped rollover manoeuvre. The numerical model of the articulated vehicle and dynamic optimisation were used to calculate appropriate braking torques for each wheel in order to restore stability. The optimisation problem requires the equations of motion to be integrated at each optimisation step and the models cannot be applied for controlling the motion in real time. Therefore, in the next step multilayer perceptron network has been proposed. Multiple dynamic optimisation tasks have been solved in order to calculate appropriate braking torques, which form a training set of the neural network. In the paper, results obtained from dynamic optimisation and neural network have been presented and compared.

Automated generation of reference dynamical models for constrained robotic systems in the presence of friction and damping effects

This paper details a new automated generation method of dynamic models of structures allowing presence of friction and damping in their models as well as subjected to position or kinematic constraints. The constraints may be material, which come from the system interaction with environment, or may be programmed. The novelty of the presented dynamics generation method is to include friction and damping into modeling and to require predefined constraint satisfaction as well. The latter requirement is critical, since when friction and damping are neglected, controllers may be inadequately designed, constraints may be violated, and overall system performance may be poor. The developed method is applied to a manipulator model, whose end‐effector performance is predefined by programmed constraints. Simulation results present manipulator constrained motion. The advantage of this method is that it serves both reference and control oriented dynamics derivation, and the final dynamics models are obtained in the reduced state form, ie, constraint reaction forces are eliminated. This is the fundamental difference between the presented approach and the Lagrange based approaches to constrained system modeling.

Establishment of optimal conditions for yeast containing sewage waters clearing by means of ultrasound

There has been investigated the effectiveness of fermentation industry sewage waters clearing by means of ultrasound. There has been established that the necessary quality indicators of water are received in as little as an hour of acoustic cavitation activity. While preserving the water, processed by the ultrasound, the meaning of the chemical use of oxygen remained the same during 2 weeks. After the ultrasound processing, there is observed a post-effect of cavitation activity, which lies in the reduction of the amount of microorganisms in the volume unit and chemical use of oxygen. The expansion in the number of microorganisms began only in 24 hours.

Analytic design of the optimum control system for five-degree-of-freedom stand simulator of the spacecraft motion

In this paper it is proposed the methodology of analytic design of the optimum structure for stochastic control system used on multi-degree-of-freedom stand simulator of spacecraft motion in the presence of deterministic and stochastic disturbances acting on it.

Generalized cost functions of avionics breakdown maintenance strategy

In this study, the generalized cost functions are proposed for choosing the optimal option of breakdown maintenance strategy of avionics systems. A mathematical model of avionics line replaceable unit (LRU) is developed. The model considers the main characteristics of the preflight checks and continuous testing of the LRU using built-in test equipment (BITE) in-flight. The equation for the mean time between unscheduled removals (MTBUR) is derived for an arbitrary and exponential distribution of time to failure. The cost functions are determined as the total operating costs separately for the warranty and post warranty period of operation. Different options of single-level, two-level and three-level maintenance are mathematically modeled and numerically analyzed for the warranty and post-warranty period of operation. The proposed analytical expressions take into account the trustworthiness of BITE, periodicity of preflight testing, cost of different maintenance operations, permanent and intermittent failure rate of LRUs and some other parameters. Numerical examples are included to illustrate the main features of the proposed mathematical models.

Actor Model Approach to Control Stability of an Articulated Vehicle

The paper presents an application of actor model to control braking torques on wheels of an articulated vehicle in an untripped rollover manoeuvre. The numerical model of the articulated vehicle and dynamic optimisation have been used to calculate appropriate braking torques for each wheel in order to restore stability. The optimisation problem requires the equations of motion to be integrated at each optimisation step and its time-consuming. Therefore, parallel computing with using actor model system has been proposed. Actor model system has been implemented in genetic algorithm. In the paper, formulation of genetic algorithm with actor system and results obtained from dynamic optimisation have been presented and compared.

Development of a Computational Based Reference Dynamics Model of a Flexible Link Manipulator

Development of a new derivation method of a reference dynamics model of a flexible link manipulator is presented in the paper. The model including flexibility can map dynamics and performance of lightweight and fast manipulators correctly and may serve their motion analysis and control design in the presence of kinematic or programmed constraints, which are assumed to be position or first order nonholonomic. The reference dynamics model is derived using the formalism of joint coordinates and homogeneous transformation matrices. This approach allows generating dynamics equations of a manipulator without formulating additional material constraint equations. The constraints present in the reference dynamics model are the programmed ones only. The flexibility of a link is modelled using the rigid finite element method. The main advantage of this method is its ability of application of the rigid-body approach to modeling dynamics of multi-body systems with flexible links. The novelty of the presented method relies on the combination of dynamics modeling of flexible system models with the programmed constraints satisfaction problem for them. The computational algorithm underlying the derivation method presented in the paper is based on Generalized Programmed Motion Equations (GPME) approach. The reference dynamics model derivation is demonstrated for a flexible link manipulator model.

Application of EVCA algorithm in dynamic optimisation of the articulated vehicle motion for control of stability: International conference on control, automation and systems (ICCAS 2016)

In many cases, solving optimisation problems, in particular a dynamic optimisation problem, is time-consuming. This is due to the long time of calculation of the objective function value. For example, during optimisation of the articulated vehicle it is necessary to integrate dynamic equations of motion in the whole time interval. The paper presents an application of own algorithm (EVCA) for reduction optimisation calculations time. This algorithm can be applied to any optimisation methods both stochastic and classical in order to speed up the optimization process. In this paper, articulated vehicle control task has been formulated as dynamic optimisation problem. During this process appropriate braking torques acting on wheels have been determined in order to restore stability of the vehicle. Results obtained from dynamic optimisation using EVCA algorithm have been presented and discussed.