Browsing by Author "Leoro, Josuet"

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A New Geometric Subproblem to Extend Solvability of Inverse Kinematics Based on Screw Theory for 6R Robot Manipulators
(1970-01-01)
Leoro, Josuet
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Hsiao, Tesheng
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Betancourt, Carlos
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電機工程學系
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Department of Electrical and Computer Engineering
Geometric inverse kinematics procedures that divide the whole problem into several subproblems with known solutions, and make use of screw motion operators have been developed in the past for 6R robot manipulators. These geometric procedures are widely used because the solutions of the subproblems are geometrically meaningful and numerically stable. Nonetheless, the existing subproblems limit the types of 6R robot structural configurations for which the inverse kinematics can be solved. This work presents the solution of a novel geometric subproblem that solves the joint angles of a general anthropomorphic arm. Using this new subproblem, an inverse kinematics procedure is derived which is applicable to a wider range of 6R robot manipulators. The inverse kinematics of a closed curve were carried out, in both simulations and experiments, to validate computational cost and realizability of the proposed approach. Multiple 6R robot manipulators with different structural configurations were used to validate the generality of the method. The results are compared with those of other methods in the screw theory framework. The obtained results show that our approach is the most general and the most efficient.
Cutting Force Monitoring and Control System for CNC Lathe Machines
(2016)
Cubas, Jorge
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Leoro, Josuet
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Reyes, Daniel
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Yeh, Syh-Shiuh
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電機資訊國際碩士學位學程
The importance of cutting forces during turning processes creates the need for a simple and low-cost solution to measure those forces. Various improvements on the cutting performance can be achieved by using these measurements. The present study explains the design and construction of a cutting force sensor, as well as the implementation of a fuzzy logic controller to obtain a complete system to monitor and control the cutting forces in rough turning operations. The force sensor uses four strain gauges attached on the sides of the tool holder to estimate the cutting forces. The force controller is designed to smoothly adjust the feed rate because a fast change in the feed rate could damage the cutting tool. The maximum cutting force needs to be input manually in this approach, because it will be the reference variable for the fuzzy controller. The maximum force is selected by the operator based on tool conditions, tool temperature, machining conditions, workpiece material, tool material, etc. A balance between the speed required to achieve the reference force and the smooth feed rate change is considered. The simulation results obtained by controlling the cutting force along with the associated machining time improvements are presented in this paper.