Janis Viba

Car rollover collision with pit corner

The paper presents a theory of body collision with pit corner. The theory can be successfully applied in approaching tasks coping with the orientation of details in technological processes and control systems, the motion of elements in mechanisms having a gap, collisions in motion of different sport objects, the analysis of car accidents etc. The applied theory deals with car motion after collision with a specific obstacle i.e. pit corner. The study is based on linear and angular momentum theorems and two restitution coefficients of normal impulse from both sides of the obstacle. The obtained results can be used for assessing road accidents in case of car collision with one or more obstacles. The object of contact may involve hitting a plane foundation, the ditch and edging of a highway or a rock in the field.

New designs of fin type propulsive devices of robotic fish

Dynamics of a fin type propulsive device of robotic fish moving inside water is studied. On the basis of Pontryagins maximum principle the optimal control law for variation of additional area of vibrating tail, which ensures maximal positive impulse of motive forces acting on tail, is found. The proposed method makes it possible to minimize energy losses within operation cycles, when fins motion is affected by water resistance forces. Thanks to that useful tractive forces increase, and operation of fin propulsive device becomes more effective. Examples on synthesis of one-tail and two-tail propulsive devices with varying working area of vibrating tail are given.

Use of Electromagnetic Impulse System for Transportation of Dry Materials and Solid Bodies

In first part of the report motion of magnetic powder materials in a vertical or inclined pipe are investigated. Mathematical models are analyzed, taking into account intensity of a pulse electromagnetic field, parameters of a powder and its interaction with the surface of the pipe and air. Experimental device, including control and measure system with the analysis of parameters by computer, is described. Second part of the report investigates a motion of non-magnetic materials. For this reason an additional magnetic container with open surface is used. After an impulse action the container stops before bound. Non-magnetic materials continue flying motion. In third part of the report the authors investigate motion excitation with impulse generator for plane vibrotransporters. It is shown that this excitation is very stable, because after impulse action the mechanical system continues vibration with a non-periodical motion and stops waiting for next impulse.

Jumping Motion of an Object Controlled by Muscle Contraction

In the design of robots, manipulators, vibrodrivers and start — stop systems it is very important to have a source of energy with internal interaction. One type of such energy sources may be found in a human or animal muscle contraction process. To synthesize new control systems for excitation or damping of a motion in start — stop systems the idea with a similar principle of action may be used. To determine internal forces, created during the contraction process, we used the Hill’s model, numerical values of corresponding parameters were taken from known biomechanical experiments. Such level of modelling allowed us to link processes of electric control and mechanical production of a force during physical exercise. The implementation of optimal control law in real control action which imitates a muscle contraction is proposed in which the discrete control signal switches in the phase plane.

Synthesis of New Mechatronic Systems by Inverse Algorithm

nverse method algorithm for invention of mechatronic systems in vibrotechnics is used for robotic systems motion control synthesis. The main difference between this method and simple analysis method is that before synthesis of a real system optimal control task for abstract initial subsystem is solved. After calculations the optimal control law is found that allows to synthesise series of structural schemes for real systems on a basis of initial subsystem. It is shown that optimal control action corresponds to the case of boundary values of area limits. For realizing optimal control actions in general case a system of one degree of freedom needs feedback system with two adapters: one for measure displacement and second for measure velocity. It is shown that simple case exists of the control with only one adapter when motion changes directions. It means that control action is like negative dry friction and switch points are along zero velocity line.

Investigation of Bodies Vibrations with Elastomeric Elements

By analyzing underwater flexible object motion, new challenges facing mechanical and engineering industry can be seen. One of typical examples is the need to solve the complex task of elastomeric (e.g. rubber or silicone) robotic objects interaction with the water boundary. Current work is an attempt to launch an investigation on elastomer dynamics of experimental and theoretical research in two directions. Experimental studies have been conducted with a sample loading on the tensile and compression machine. Theoretical research investigation proposes a new model with internal interactions inside elastomers. Model is based on common lateral and diagonal interaction links between cross-sections of a material. Results of the work are applied for vibration systems motion modeling. Additionally, a new dynamical material model may be applied for the imitation of muscle dynamics and thus to provide basis for further applications in biomechanics such as development of artificial muscles.

Optimization and Synthesis of a Robot Fish Motion

Inverse method algorithm for investigation of mechatronic systems in vibration technology is used for robotic systems motion control synthesis. The main difference of this method in comparison with simple analysis method is that before synthesis of a real system the optimal control task for abstract initial subsystem is solved [1 4]. As a result of calculations the optimal control law is found that allows to synthesize series of structural schemes for real systems based on initial subsystem. Is shown that near the optimal control excitation new structural schemes may be found in the medium of three kinds of strongly non–linear systems: systems with excitation as a time function; systems with excitation as a function of phase coordinates only; systems with both excitations mixed [2 – 4]. Two types of vibration devices are considered. The first one is a vibration translation machine with constant liquid or air flow excitation. The main idea is to find the optimal control law for variation of additional surface area of machine working head interacting with water or air medium. The criterion of optimization is the time required to move working head of the machine from initial position to end position. The second object of the theoretical study is a fin type propulsive device of robotic fish moving inside water. In that case the aim is to find optimal control law for variation of additional area of vibrating tail like horizontal pendulum which ensures maximal positive impulse of motion forces acting on the tail. Both problems have been solved by using the Pontryagin’s maximum principle. It is shown that the optimal control action corresponds to the case of boundary values of area. One real prototype was investigated in linear water tank.

Optimal Synthesis Method for Invention of New Mechatronic Systems in Vibrotechnics

The authors provide inverse method algorithm for invention mechatronic systems in vibrotechnics. The main difference of this method compared to a simple analysis method is that initial subsystem is solved before a synthesis of real system optimal control task for abstract. After the calculations optimal control law is found, which allows synthesizing series of structural schemes for real systems to close initial subsystem. It is also shown that near the optimal control excitation new structural schemes may be found within three kinds of strongly non-linear (impact) systems: systems with excitation as a time function; systems with excitation as a function of phase coordinates only; systems with mixed both excitations.

Synthesis of Vibrator with Air or Water Flow Excitation

In the daily life and in using technologies people interact with continuous medium like air or water. In present article a motion of the vibrator with constant air or water flow excitation is observed. In the first part of the article a motion of the vibrator with constant air or water flow velocity excitation is investigated. The main idea is to find optimal control law for variation of additional area of vibrating object within certain limits. The criterion of optimization is the time required to move object from initial position to end position. For the solution of high-speed problem the maximum principle is used. It is shown that optimal control action is on boundaries of area limits. Examples of synthesis of real mechatronic systems are given.

Eenergy Extraction from air or Water by Vibrations

Eenergy Extraction from air or Water by Vibrations The paper considers the possibility to derive energy from air or water in a non-traditional way (without using rotating equipment). For this purpose, the authors studied variations in the additional area of a vibrating object in a definite sequence found as the solution of an optimisation problem. In the work, stably moving mechatronic systems were synthesised and modelled, whose control is very simple (not requiring calibration), being a function of the changing sign of phase coordinates. Energijas Ieguve no Gaisa Vai Ūdens Plūsmas ar Vibrāciju Palīdzību Rakstā aplūkota iespēja iegūt energiju no gaisa vai ūdens plūsmas netradicionālā veidā, nelietojot rotējošas iekārtas. Tam nolūkam izmantota svārstību sistēmas objekta papildus laukuma maiņa noteiktā secībā, kas atrasta optimizācijas uzdevuma atrisinājumā. Sintezētas un modelētas stabilas kustības mehatroniskās elektromehāniskās sistēmās (MEMS), kurās vadības sintēzē izmantotas fāžu koordināšu zīmju maiņa.