Säännöstelty huvi : suomalainen ravintola 1900-luvulla

Väitöskirja,Tampereen yliopisto

Rumuuden politiikka: sukupuoli, ruumis ja kansallisuuden rakentuminen 1900-luvun alun Suomessa

Abstract: Politics of ugliness: gender, body and the construction of nationality in early twentieth century Finland

Perheestäkö turva? : vanhat naiset ja perhe Vihdissä 1800- ja 1900-luvun alussa

Summary: Sheltered by the family

Oman aikansa Kiina-ilmiö : suomalaisten lähetyssaarnaajien kokemuksia länsimaisen ja kiinalaisen kulttuurin ja uskonnon kohtaamisesta 1900-luvun alussa

Zusammenfassung: Das China-Phänomen : über die Erfahrungen finnischer Missionsprediger bei der Begegnung westlicher und chinesischer Kultur und Religion Anfang des 20. Jahrhunderts

Improving Dynamic Characteristics of Open-loop Controlled Log Crane

The improvement of the dynamics of flexible manipulators like log cranes often requires advanced control methods. This thesis discusses the vibration problems in the cranes used in commercial forestry machines. Two control methods, adaptive filtering and semi-active damping, are presented. The adaptive filter uses a part of the lowest natural frequency of the crane as a filtering frequency. The payload estimation algorithm, filtering of control signal and algorithm for calculation of the lowest natural frequency of the crane are presented. The semi-active damping method is basedon pressure feedback. The pressure vibration, scaled with suitable gain, is added to the control signal of the valve of the lift cylinder to suppress vibrations. The adaptive filter cuts off high frequency impulses coming from the operatorand semi-active damping suppresses the crane?s oscillation, which is often caused by some external disturbance. In field tests performed on the crane, a correctly tuned (25 % tuning) adaptive filter reduced pressure vibration by 14-17 % and semi-active damping correspondingly by 21-43%. Applying of these methods require auxiliary transducers, installed in specific points in the crane, and electronically controlled directional control valves.