Dariusz Sędziak

Controllability of MR shock absorber for vehicles

In the paper, shock absorbers with magnetorheological (MR) fluids were described. These elements can be used in many applications related to vehicle machines such as bumpers, dampers, shock absorbers, vibration eliminators, etc. Basic theoretical relationships which allow design and modelling of MR fluid shock absorbers are shown. Experimental designs of MR absorber and some example results of research were presented and discussed. The application of PI force controller used to improve the dissipation characteristic of built MR shock absorber has been shown.

The Use of Magnetorheological Fluid Dampers to Reduce Servo Drive Velocity Jumps due to Load Changes

A problem of velocity control of servo drives in the presence of high load changes is described and studied in this article. The rapid fall of load causes an unexpected jump of the movable elements of the machine. The increase of velocity is harmful and may be reduced by usage of electrically controllable dampers. Such dampers employ a magnetorheological fluid that changes its properties in the presence of a magnetic field. This results in a damper whose characteristics may by adapted in real time to the user’s requirements. In this article the construction of such a damper is described and a machine tool servo drive with an MRF damper is presented. Its simulation model is proposed and some simulation and control analyses are made. Finally experimental results of servo drive velocity control in the presence of load changes are presented. The article is focused on velocity jump reduction which is caused by load decrease.

Design and Investigations into the Piezobender Controlled Servovalve

Electrohydraulic servo drives can be found in many industrial applications. A typical design of a servovalve uses the known torque motor. The main concept of designing the modification of the servovalve described in the paper was concern about the application of a piezobender as an actuator, working between nozzles as a flapper, at a control stage. The paper presents and investigates the design of a power amplifier for piezobenders and a digital controller for an electrohydraulic servo valve with a piezobender element. The article shows and discusses the main concept of design and the results of experimental investigation.

Modelling of Electrohydraulic Drive with a Valve Controlled by Synchronous Motor

The article describes modelling of electrohydraulic servo drive. In the drive a new type of proportional valve with a synchronous motor controlled by dedicated power electronics is used. The model of the electrohydraulic servo drive prepared in Matlab-Simulink is described. The study included the examination of the basic characteristics such as step response.

HMI with Vision System to Control Manipulator by Operator Hand Movement

In the paper, the vision system for control of manipulator by operator’s hand movement is presented. The Authors propose method which uses specific colors of markers. The fast camera 3iCube (frequency 50 Hz) was used and connected with PC by USB 3.0. The position of the manipulator was controlled by industrial controller. Connection between PLC and PC was realized by TCP/IP protocol. The two green markers were used to scale operator’s working area. One green marker indicated a base coordinates of manipulator. The red marker was held in hand by operator. Movement of the red marker was in ratio 1:2 to manipulator. The research was focused on the correctness of detection of markers and response trajectory of the manipulator. Proposed method can be used to control manipulator movement by operator without uses classic control panel. The research proves possibility of application of the vision system for control of manipulator.

Research of Basic Parameters of Piezoelectric Tube Actuator

The article present basic research of the piezoelectric tube actuator. In this study the actuator was tested for various DC voltages. Further hysteresis and creep effect of the piezo ceramic material were presented. The next point of this research was positioning control of tube under closed loop control. For this purpose classic PID control algorithm was applied, with a negative feedback from laser displacement sensor. The control software was developed under Matlab Simulink and dSPACE control system, which allows fast modification and testing.

THE USAGE OF ACCELERATION SIGNAL TO CONTROL MAGNETO-RHEOLOGICAL FLUID DAMPER.

A semi-active controllable linear magneto-rheological (MR) fluid damper is described and studied in this paper. The damping characteristics of the damper may be adapted in real time to the users requirements. Such dampers can then be used to eliminate vibrations in applications like vehicles and different machines. In this paper, a simple control method, which uses an acceleration signal to switch the damper on and off, is proposed. The construction of such a control system is described and finally experimental results of oscillation damping are presented.