Please use this identifier to cite or link to this item: http://dx.doi.org/10.14279/depositonce-2344
Main Title: Development and Evaluation of a Semi-active Suspension System for Full Suspension Tractors
Translated Title: Entwicklung und Untersuchung eines semiaktiven Federungssystems für vollgefederte Traktoren
Author(s): Sarami, Shahriar
Advisor(s): Meyer, Henning J.
Granting Institution: Technische Universität Berlin, Fakultät V - Verkehrs- und Maschinensysteme
Type: Doctoral Thesis
Language: English
Language Code: en
Abstract: Federungssysteme können den Fahrkomfort und das dynamische Verhalten von Traktoren verbessern. Aus diesem Grund werden moderne landwirtschaftliche Traktoren mit verschiedenen Federungssystemen ausgestattet, wie Vorderachs-, Sitz- und Kabinenfederung oder der Federung des Aufbaus. Besonders bei der Vorderachsfederung kommen hauptsächlich passive Regelungssysteme zum Einsatz. Die Hinterachse ist bei Standardtrakoren in der Regel ungefedert. In dieser Untersuchung wurde die Anwendung eines semiaktiven Federungssystems in landwirtschaftlichen Traktoren betrachtet. Hierzu wurde ein Testtraktor mit einem hydropneumatischem Federungssystem für die Hinterachse und einem konventionellen Vorderachsfederungssystem ausgerüstet. Gleichzeitig wurde von dem Traktor ein Simulationsmodell mit dem Programmpaket Matlab-Simulink erstellt. Mit Hilfe von Experimenten wurden Messungen mit der entwickelten semiaktiven und passiven Fahrwerksregelung auf dem hydraulisch angetriebenen Fahrbahnsimulator der TU Berlin durchgeführt und mit den Ergebnissen aus den Simulationsrechnungen verglichen. Hierbei wurde auch das entwickelte Modell verifiziert und validiert. Es konnte festgestellt werden, dass die Traktorbeschleunigungen mit dem semiaktiven System um bis zu 13 % verkleinert werden konnten. Die dynamische Reifenkraft konnte um 6 % gegenüber dem passiven System reduziert werden. Generell war festzustellen, dass mit einem semiaktiven System der Fahrkomfort und die Fahrsicherheit entscheidend verbessert werden können.
Conventional primary agricultural tractors have no suspension systems. Since the usage of suspension systems in tractors improves the ride comfort and dynamic behavior of them, modern agricultural tractors are equipped with different suspension systems such as seat, cabin, or chassis suspension. The technology of the suspension systems for tractors is developing. Recently, some tractor models are presented with the frame construction. These tractors can be equipped with both front and rear axle suspensions. However, the efficiency of the passive suspensions is limited, and the idea of active systems is considered nowadays with the aim of improving the performance of vehicle’s suspensions. With recent progress in electronic technology, this idea is going to be more and more practicable. In this investigation, utilization of the active suspension was considered along with development in the suspension technology of agricultural tractors. As the first step, the background of the research was studied that led to select semi-active suspensions as proper systems for agricultural tractors. In addition, as the control strategy of this system, on-off skyhook was selected. In order to evaluate this new system experimentally, a test-tractor was determined. This tractor, called TU-Trac was a full suspension test-tractor with hydro-pneumatic rear suspension. During this research work, the rear axle suspension was equipped with a semi-active control system. In order to evaluate the new suspension system, two approaches of the computer simulation testing and experimental testing were used. For the first one, the computer model of the tractor and suspension system, using MATLAB-Simulink program, was built. For the second approach, the prototype of the new suspension system including a set of the sensors, hydraulic actuators, and electronic controller was developed, and then, they were installed on the tractor suspension. After that, the test design and test plan of the simulation and experimental tests were determined. The suspension system was excited by three sets of impulse inputs, which were applied to the four tractor’s wheels. Each test was performed once on the tractor with passive suspension mode, and then, the same test was performed this time with the semi-active suspension computer model. In the experimental tests, a suspension test rig was used to apply the test inputs to the tractor. This test rig is a part of the facilities at the TU Berlin -Department Machinery System Design. The outputs of the tests were the acceleration data of the tractor body and wheels. These data were analyzed to obtain the time and frequency domain results of them. These results were used in two groups of the body accelerations and dynamic tire forces in order to evaluate the ride comfort and handling ability of the tractor. Using these results, overall computer model was validated by comparing the simulation results with experimental one. Then, the comparative results of the passive and semi-active modes of the simulation and experimental tests were used in order to evaluate the performance of the new suspension system. This comparison demonstrated until 13 % reduction on the average of the tractor body accelerations that showed significant improvement in the ride comfort of the tractor. Additionally, the average of the dynamic tire force of the tractor was reduced until 6 % showing that tractor handling was not reduced, but also it was improved significantly. As conclusion, the overall performance of the tractor’s suspension was increased by using the new suspension system.
URI: urn:nbn:de:kobv:83-opus-24990
http://depositonce.tu-berlin.de/handle/11303/2641
http://dx.doi.org/10.14279/depositonce-2344
Exam Date: 2-Sep-2009
Issue Date: 18-Jan-2010
Date Available: 18-Jan-2010
DDC Class: 620 Ingenieurwissenschaften und zugeordnete Tätigkeiten
Subject(s): Experimente
Semiaktive Federung
Simulation
Skyhook
Traktor
Experimental tests.
Semi-active suspension
Simulation
Skyhook
Tractor
Usage rights: Terms of German Copyright Law
Appears in Collections:Institut für Konstruktion, Mikro- und Medizintechnik » Publications

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