M. Kciuk

SMA actuators: theory, performance curves and design problems

Purpose – The main purpose of the paper is to develop model basing on the modified and properly‐adopted Fermi‐Dirac equation which combines proper accuracy with adequate simplicity as well as to show how steady state and transient curves resulting from this model can be applied for solving design task.Design/methodology/approach – The standard Fermi‐Dirac equation was modified and extended. Full performance cycle for the SMA actuator was characterized by double‐valued function describing the actuator activation and the actuator deactivation. All these functions and parameters can be easily determined by analysis of measurement data or with use of Hooke‐Jeeves optimization algorithm.Findings – SMA linear actuator can be used in mechatronic systems as a special non‐standard drive when ultra‐light mass and very simple mechanical construction of power feed system is required. The proposed steady‐state and transient performance curves as well as operation diagram constitute sufficient base for effective design...

OpenWRT operating system based controllers for mobile robot and building automation system students projects realization

Two projects were described and compared. Both of them are students projects. Experience gained during the first project realization enabled to realize second one. The common part of the projects is programming system controller in OpenWRT operating system. Both devices are controlled using website control panel, so they do not need dedicated software on the remote computer installed, typical web browser is enough. All functionality for controlling and management is implemented in router.

Computer-Based Measurement System for Complex Investigation of Shape Memory Alloy Actuators Behavior

Shape Memory Alloys belong to group of so called “SMART” materials, which became more and more popular last years. The smartness of that kind of materials is defined as possibility of its particular properties stimulation using physical or chemical way. Shape Memory Alloy (SMA) is able to change its size (shape) when temperature is changing. Shape Memory Effect (SME) is macroscopic effect of martensitic transition which overlap inside the material. There are two characteristic states of SMA: low temperature – martensitic – state and high temperature – austenitic – state. Material can be easily plastically deformed by relatively small mechanical force in martensitic state. In opposite, material is strong and very hard to deform in austenitic state it is only elastic deformation viable. During martensitic transition internal crystal order changes, which causes change of material’s properties. Material returning to its natural shape during reverse martensitic transition (from austenitic to martensitic state) can put pressure or perform mechanical work. Complex behavior of SMA materials can be illustrated by thermo-mechanical characteristic (Fig.1).

Measurements of Shape Memory Alloy actuator for a self-switching electrical fuse

This paper describes chosen results of the measurements of various characteristics of Shape Memory Alloy wire in purpose of its usage as an actuator for self-switching electrical fuse. The experiments were performed by talented pupil of secondary school as a research project co-financed by Polish Ministry of Science and Higher Education. Measurement system consisting of power supply unit PSH-3620a and PC computer with running LabVIEW application is used to control the measurement procedures. Program of experiments consists of static measurements (static switching current), dynamic measurements (switching times) and exploitation measurements (switch off time). The paper presents chosen resultant characteristics.

Design and prototype of fuse activated by SMA wire

The paper presents the origin and general idea of a didactic project realized at the Department of Mechatronics at the Silesian University of Technology in Gliwice, Poland. Technical goal of the project is to design and examine a prototype of electrical fuse activated by Shape Memory Alloy (SMA) wire. Project is realized at the University by a schoolboy of a secondary school under the supervision of two PhDs. Educational goal of the project is to develop unique talents and abilities of extraordinarily talented pupil of secondary school - Kamil Swiatek. Problem Based Learning methodology as well as Learning by Doing is implemented. The article presents the measurement methodology and prototype measurement stand. PC controlled power supply unit changes SMA wire supply mode of operation among current control and voltage control in real time. Results and analysis of static measurement is done, as well as two steps of dynamic measurements. The waveforms of exemplary measurement routines show the results of investigations. Advantages and disadvantages of the proposed solution are discussed.