Abstract
Multidisciplinary design optimization has been widely applied in the optimization of large-scale complex system and also in the design and optimization of components, which are involved in multidisciplinary behaviors. The wear and fatigue life of lead screw actuators is a typical multidisciplinary problem. The wear behaviors of actuators closely relate to many factors such as loads, lubrications, materials properties, surface properties, pressures, and temperature. Therefore, the wear and fatigue life of actuators cannot be modeled without a simultaneous consideration of solid mechanics, fluid dynamics, contact mechanics, and thermal dynamics. In this paper, the wear and fatigue life of a lead screw actuator is modeled and validated. Firstly, the theory of asperity contact and Archard’s model of sliding wear are applied to estimate the amount of wear under certain circumstances. Secondly, a test platform is developed based on a standard ASTM test protocol, and the wear phenomenon at the ball-on-flat sliding is measured to validate the developed wear model. Thirdly, finite element analysis is conducted using Nastran to assess the contact stresses in the lead screw and nut assembly model. The estimated data from the three sources are finally merged to formulate a mathematical model in predicting the wear and fatigue life for the optimization of lead screw actuators.
Highlights
Robotic technologies are playing more and more significant roles in our modern society
A lead screw linear actuator is a mechanism that converts an input in the form of a rotary motion into a desired linear motion
The mathematical models of wear have been developed to correspond the load with fatigue life of actuators
Summary
Robotic technologies are playing more and more significant roles in our modern society. The ultimate goal of the presented work is to provide durable actuators for robotic design optimization from the perspective of cost and functionalities. Robots can be treated as a set of basic modules, comprising rotary or linear modules as actuators and connecting modules for robotic structures. Linear actuators are selected based on many aspects such as cost, precision, maximized loads, maximized speeds, and stiffness [9]. It is our observation that the methodologies and data are lacking to help robotic designers select modular components in particular, when the design criteria of precision, cost, and fatigue life have to be considered simultaneously to optimize the system performance of a robot. The focus of this paper is design of the low-cost lead screw linear actuators.
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