tailieunhanh - Motion of mechanical systems with non-ideal constraints
In the paper a new method for mechanical systems with non-ideal constraints is presented. It is proved that a mechanical system subjected to physical non-ideal constraints cannot be determined purely by theoretical analysis because the reaction forces depend on the physical parameters of interactive environment, which are identified only by measurement. The principle of compatibility is shown to be an effective tool in combination with experience to investigate such a problem. For illustration the dynamics of a digging machine is investigated. | Volume 35 Number 2 2 Vietnam Journal of Mechanics, VAST, Vol. 35, No. 2 (2013), pp. 157 – 167 MOTION OF MECHANICAL SYSTEMS WITH NON-IDEAL CONSTRAINTS 1 Do Sanh1,∗ , Dinh Van Phong1 , Do Dang Khoa2 Hanoi University of Science and Technology, Vietnam 2 Medisend International, USA E-mail: ∗ dosanhbka@ Abstract. In the paper a new method for mechanical systems with non-ideal constraints is presented. It is proved that a mechanical system subjected to physical non-ideal constraints cannot be determined purely by theoretical analysis because the reaction forces depend on the physical parameters of interactive environment, which are identified only by measurement. The principle of compatibility is shown to be an effective tool in combination with experience to investigate such a problem. For illustration the dynamics of a digging machine is investigated. Keywords: The principle of compatibility, non-ideal constraints, physical constraints, interactive environment, method of transmission matrix. 1. INTRODUCTION The motion of mechanical systems under both physical and program constraints is paid more and more attention in technology and in automatic control industry. In the physical constraints, both the ideal and non-ideal constraints are attracted a lot of interests but only ideal constraints are considered. The non-ideal constraints are rarely discussed due to the fact that it is impossible to define the work (of virtual displacements) of the reaction forces corresponding to the non-ideal constraints. Therefore, the corresponding generalized forces cannot be determined. Up to now only the Coulomb friction constraints are considered as a particular case of non-ideal constraints which were mentioned in papers [4, 9-13]. However, non-ideal physical constraints are often met in practical applications, for example in machine tools (milling machine, lathe, planer, honing machine, etc.) or front loaders, and scoop loaders. Working surfaces created by machine .
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