Recently, robotic technology has begun to play an important role in forestry operations. An important class of forestry machines is comprised of systems equipped with a mobile platform fitted with an articulated arm carrying a tree processing head. The dynamics of such systems are needed for simulation and control purposes. In contrast to conventional industrial manipulators, which are mounted on stationary bases, a mobile manipulator is dynamically coupled with its base. Base compliance, non-linearity and coupled dynamics result in positioning inaccuracies which in turn give rise to control problems. / The dynamics of the FERIC forwarder forestry machine including its compliant tires were developed and implemented symbolically in compact form with the help of an iterative Newton-Euler dynamic formulation. Various models with increasing complexity were derived. Based on a simplified dynamics model, a valve-sizing methodology was developed and used to size hydraulic proportional valves of the machine's actuators. / System parameters have been obtained by various methods, including use of blueprints, weighing, solid modeling and various experiments. A set-point feedforward controller was designed and the machine's responses for various inputs were obtained to analyze the dynamic behavior of the system. Although initial simulations were done in Matlab and Simulink, C programs were developed for increased speed of execution. In addition, techniques to minimize computation time have been developed and applied to result in almost real time simulation.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.27255 |
| Date | January 1996 |
| Creators | Sarkar, Soumen. |
| Contributors | Papadopoulos, Evangelos (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Engineering (Department of Mechanical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001554426, proquestno: MQ29628, Theses scanned by UMI/ProQuest. |
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