Online Estimation of Linear Tooth Belt Drive System Parameters

Abstract

Many control schemes rely on an analytical model of the servomechanism to be controlled, and hence, accurate knowledge about the position-and timedependent parameter variability becomes crucial in many contexts, such as robust control methods. Although a properly designed robust controller can cope with a large parameter variation, real-time identification of the system parameter behavior could lead to several advantages by means of monitoring the varying dynamics, e.g., the predetermined uncertainty region around the nominal value. This paper addresses issues in online parameter estimation of a linear tooth belt drive with a limited stroke. Particular attention is paid to detecting the position-dependent changes in the system dynamics by using recursive least squares algorithm and exciting the system in different cart positions in order to identify the varying dynamics. The algorithm used is based on an indirect output-error identification scheme. The experimentally estimated parameters are compared with the corresponding two-mass model parameters. The results show an acceptable agreement and demonstrate the feasibility of the estimation method to estimate the parameters of a closed-loop controlled servomechanism with a limited stroke and time-varying parameters.Index Terms-Closed-loop identification, estimation, linear tooth belt drive, online, variable structure systems. I. INTRODUCTIONL INEAR movement is often needed with different industrial applications. Linear tooth belt drives offer low-cost solution for linear movements with a wide operating range and capability for high-speed use, and they are traditionally used in different conveyor applications and pick-and-place solutions. The main difficulties with linear tooth belt systems come from the elastic structure of the tooth belt itself, which sets the system's natural frequency low and limits the control bandwidth. Although the linear tooth belt drive has many drawbacks in [1], tooth belt drives are used in a high-precision laser-cutting application, which shows that, with proper control design, a linear tooth belt system can be applied to demanding linear applications as well. High performance of linear tooth belt drives requires that the system disturbances, parameter Manuscript

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