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Nelson Woo

In Machinery, Machinery General, Research

Optimal Control of passive Locking Mechanism for Battery Exchange Using Pontryagin’s minium principle

Optimal Control of passive Locking Mechanism for Battery Exchange Using Pontryagin’s minium principle

Wonsuk Jung, Jongwon Park, Seungho Lee, Kyungsoo Kim, Soohyun Kim, 8th Asian Control Conference (ASCC), Kaohsiung, May 2011, pp 1227-1232.

Abstract

Mobile robot market and its importance are rapidly increasing. Mobile robots usually mount batteries to extend operating time and workspace. For that, robot has to charge the battery while stopping at a station or exchange the battery. Charging battery is too slow to restart robots. Therefore, battery exchanging method is encouraged. Until now, this method needs expensive sensors such as laser range finder and vision sensors to align and is very complex mechanism which including battery removal from robot, moving to the station, docking mechanism and exchange mechanism. Thus, we proposed a new complete passive battery docking and exchange mechanism. This mechanism uses no actuators at whole actions. And it simplifies the process that unifies the docking and exchange mechanism using key and housing system. This system reduces the docking and exchange operating time and compensates wide range of offset between battery and charge station. But this mechanism needs optimal control of robot moving, because this system is composed of springs and dampers which are passive modules that should be controlled accurately. This paper proposes optimal control of robot moving at passive docking mechanism in battery system for reducing docking time, rebounding force and stable docking using Pontryagin’s minimum principle. Also this paper verifies proposed optimal control using dynamic analysis program, Recurdyn and Matlab Simulink.

How Multibody Dynamics Simulation Technology is Used

An efficient method to dock and exchange batteries for a mobile robot was verified using RecurDyn. RecurDyn was able to evaluate the dynamics of the system with a specific control method without experimentally testing each case.

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March 15, 2011: Analysis and Simulation Software Applied to Latest Mars Rover

Analysis and Simulation Software Applied to Latest Mars Rover

Ms. Kendra Short of NASA Jet Propulsion Laboratory will discuss this topic as the keynote speaker of the PLM World Simulation Connection. The presentation will take place on Tuesday May 3, 2011 and is entitled:

“Mars Science Laboratory”

Ms. Kendra Short is the manager of the Mechanical Systems Division at the Jet Propulsion Laboratory. She has been at JPL for over 20 years starting as a mechanical hardware engineer and has worked on the Cassini, Mars Pathfinder, and Shuttle Radar Topography Mission (SRTM) programs. More recently she has held several organizational and project management roles. She earned a BS in Mechanical & Aerospace Engineering from Princeton University in 1989 and an MS in Aero/Astro from Stanford University in 1992.

Kendra will discuss the Mars Science Laboratory mission, which is NASA’s next generation rover to explore the surface of Mars and is scheduled for launch in 2011. The vehicle design is driven by an entwined combination of geometry constraints, complex and varied loading events and environmental extremes. Her talk will address many of the challenges and their solutions through the application of analysis and simulation software.

We hope you will be able to attend the conference to see this and other great presentations. Online conference registration is available at http://event.plmworld.org/.
In Research, Tracked Vehicles Construction, Tracked Vehicles General

Research on the Simulation of the Driving System of a Crawler Bulldozer

Research on the Simulation of the Driving System of a Crawler Bulldozer

Zhang Yaojuan, Cheng Kai, Zuo Peng, Wang Zhilin, Transportation, Mechanical, and Electrical Engineering (TMEE) International Conference, Changchun, 2011, pp. 703-706.

Abstract

The multibody dynamics model of a crawler bulldozer is established in this paper using tracked vehicles’ subsystem Track (LM) of multibody dynamics simulation software RecurDyn, and the simulation analysis of driving system performance is carried out. In the process of simulation, this paper focuses on the analysis of the road wheel’s force, driving wheel’s force and crawler tension in the process of operation in two kind pavement of the clay and hard. Then, the improvement measures have been put forward that the driving wheels had better use shock absorber and the strength and stiffness of track shoe pin should be increased. The simulation analysis result provides reference for the structure optimization design of crawler bulldozer and how to extend the service life of the crawler driving system.

How Multibody Dynamics Simulation Technology is Used

Construction vehicle dynamics can be quickly modelled using RecurDyn’s Track (LM) toolkit. Individual sections of the system can be easily modified within the model to efficiently improve the design of the tracked vehicle. The ground module in RecurDyn is used to simulate both clay and hard pavement. Dynamic simulations were able to show that a shock absorber was necessary and the stiffness of the track shoe pin should be increased.

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November 30, 2010: First Chinese Textbook About RecurDyn Multibody Dynamics Software Published

FOR IMMEDIATE RELEASE

First Chinese Textbook About RecurDyn Multibody Dynamics Software Published

Publishing Indicates Growing Demand for RecurDyn Analysis as Part of Increased Innovation in Quickly Expanding Economy

November 30, 2010, Shanghai, China – A textbook about RecurDyn Multibody Dynamics software has been published by the Tsinghua University press in simplified Chinese. The first printing was 4,000 copies. Tsinghua University is a highly regarded technical university in China.

This RecurDyn book contains 10 chapters and 457 pages and was written by Xiaojuan Jiao of the Pro-Lambda Corporation.