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Study on the Modeling and Control Method of FMS in High Speed and Reciprocating Movement

Author: LiuYang
Tutor: TangKeHong
School: Jilin University
Course: Mechanical and Electronic Engineering
Keywords: FMS to-and-fro movement at high speed multi-level inverse dynamics nonlinear extremum promblem with a condition
CLC: TH113
Type: Master's thesis
Year: 2009
Downloads: 42
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Abstract

In this article we provides a new way for the matters such as multi-level inverse dynamics model of speedy FMS (flexible multibody system) and efficient open-loop control.the nonlinear and strong coupling of FMS makes the related dynamics model become the hot topic for researchers,but the inverse dynamics model of FMS still demands furhter study.And in some work conditions—at high speed and low rigidity,it’s difficult to achive traditional closed-loop feedback control,and we have to create an practical inverse dynamics model for efficient feed-forward control if the accurate control is required.In this article we tries to introduce the slowly varying vibration to create a multi-level inverse dynamics model according to the features of reciprocating movement of set-up at high speed; and regarding with the requirements, work conditions,target position and accuracy of positioning to manage the law of motion,and to fulfill the efficience and minimize T while to guarantee the reqirements of the accuracy, which will lead to an open-loop control.The main contents of this article are following:1.We disigned the simple and practical telescopic body and builded the corresponding dynamics model under the work background of picking tea.The builded model should not only show the system’s physical characteristics, but also facilitate the following inferential process—mainly requires the bulk movement description and sports exercise described the separation as far as possible in the form .This article adopts the following theories: based on the assumption of elle beam’s small deformation,we use the principle of virtual work and relative descrition which are found in analytic dynamic.We adopt the moving coordinates system with endpoint connectionand expend the elastic deformation under the simply supported beam bending vibration mode and get the first two phases’ modes and describe the constraints though leading in Lagrange multipilers vector.2.With the concept of slow-varying vibration and the characteristics of body exercise, we designed a multi-level inverse dynamics model. First, we set the dynamic equations of elastic coordinates of the first order, second-order time derivative of purchase for 0, thus solving the whole exercise at a‘slow-varying vibration’within the meaning of elastic coordinate ; And in accordance with the characteristics of sport --Getting to the location of the end goal within a short time before and after exercise may be similar to the view that speed is always 0, to simplify the dynamic equations , to solve more precise coordinates flexibility, and then , make use of vibration formula to describe the location of the end goal before and after the arrival of the vibration of the situation.3.Based on Taylor series ,expand the exercise variables,and boils down working condition requirements to bounded conditional extremum problem , and then formulate a control strategy. First of all,though expandingθ1 andθ2 in Taylor series,describe the movement comes down to a very unconventional spline problem, in The sense of the slow change. The process of trajectory planning, can credit the bending deformationthe to the size effect on the impact of the end position,This makes the drive control strategy timeliness reach to the Maximize. In addition, assumed that getting the location of the end goal within a short time before and after the elastic vibration of the quick change can be seen as part of simple harmonic motion ,we can make use of elastic vibration energy law to set up the relationship between flexibility and precision, thus to ensure the accuracy requirements, and balance the efficiency and positioning accuracy requirements. Based on target position and accurcy make out the movement,seek to arrive at the location when the goal of positioning accuracy to meet the circumstances.4.Take advantage of the characteristics of working conditions,in ensuring the accuracy of the premise of safety,formula for the control of an appropriate simplification, makes the Control algorithm allows more time-sensitive.Simple manner has the following two aspects: 1)at the premise of the vibrational energy of the elastic coordinates enlarge reasonable treatment; 2)linearizing the sports variables on the triangle .5. Testify the algorism in article, simulinking it though ADAMS and simulink module in MATLAB, taking the forward model in ADAMS as the exact solution. And nonlinear extremum promblem with a condition is solved though use the related commands of Optimization Toolbox in MATLAB.

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