Good understanding of relationship between parameters of vehicle, terrain and interaction at the interface is required to develop effective navigation and motion control algorithms for autonomous wheeled mobile robots...Good understanding of relationship between parameters of vehicle, terrain and interaction at the interface is required to develop effective navigation and motion control algorithms for autonomous wheeled mobile robots （AWMR） in rough terrain. A model and analysis of relationship among wheel slippage （S）, rotation angle （0）, sinkage （z） and wheel radius （r） are presented. It is found that wheel rotation angle, sinkage and radius have some influence on wheel slippage. A multi-objective optimization problem with slippage as utility function was formulated and solved in MATLAB. The results reveal the optimal values of wheel-terrain parameters required to achieve optimum slippage on dry sandy terrain. A method of slippage estimation for a five-wheeled mobile robot was presented through comparing the odometric measurements of the powered wheels with those of the fifth non-powered wheel. The experimental result shows that this method is feasible and can be used for online slippage estimation in a sandy terrain.展开更多
The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated b...The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria （WIN）. And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.展开更多
西北工业大学濮良贵教授主编、高等教育出版社出版的《机械设计》是一本机械设计领域的经典教材,自出版以来,在很多高校的机械工程相关专业中广泛使用,深受好评和欢迎。本文捡取了该教材中我们认为或论述有问题、或解释不够简明、或没...西北工业大学濮良贵教授主编、高等教育出版社出版的《机械设计》是一本机械设计领域的经典教材,自出版以来,在很多高校的机械工程相关专业中广泛使用,深受好评和欢迎。本文捡取了该教材中我们认为或论述有问题、或解释不够简明、或没有展开深入解释、或表达有错误的若干问题,从数学角度给予了详细的解释或证明。这些问题是我们在教学实践中感到青年教师和学生理解比较困难、困惑比较多的问题,搞清楚这些问题的理论基础,有利于加深理解教材、提高教学质量。“Mechanical Design”, edited by Professor Pu Lianggui from Northwestern Polytechnical University and published by Higher Education Press, is a classic textbook in the field of mechanical design. Since its publication, it has been widely used in mechanical engineering related majors in many universities and has received high praise and popularity. This article selects several issues from the textbook that we believe have problems with the discussion, lack concise and clear explanations, have not been elaborated and explained in depth, or have errors in expression, and provides detailed explanations or proofs from a mathematical perspective. These issues are difficult and confusing for young teachers and students to understand in our teaching practice. Clarifying the theoretical basis of these issues is beneficial for deepening understanding of textbooks and improving teaching quality.展开更多
基金Project(60775060) supported by the National Natural Science Foundation of ChinaProject(F200801) supported by the Natural Science Foundation of Heilongjiang Province,China+1 种基金Project(200802171053,20102304110006) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(2012RFXXG059) supported by Harbin Science and Technology Innovation Talents Special Fund,China
文摘Good understanding of relationship between parameters of vehicle, terrain and interaction at the interface is required to develop effective navigation and motion control algorithms for autonomous wheeled mobile robots （AWMR） in rough terrain. A model and analysis of relationship among wheel slippage （S）, rotation angle （0）, sinkage （z） and wheel radius （r） are presented. It is found that wheel rotation angle, sinkage and radius have some influence on wheel slippage. A multi-objective optimization problem with slippage as utility function was formulated and solved in MATLAB. The results reveal the optimal values of wheel-terrain parameters required to achieve optimum slippage on dry sandy terrain. A method of slippage estimation for a five-wheeled mobile robot was presented through comparing the odometric measurements of the powered wheels with those of the fifth non-powered wheel. The experimental result shows that this method is feasible and can be used for online slippage estimation in a sandy terrain.
文摘The study examined the impact of using power tiller as a means of mechanizing lowland rice production in Nigeria. The study was carried out in Bida area, Niger State, where the sawah rice production was disseminated by Watershed Initiative in Nigeria （WIN）. And in Ajase Ipo of Kwara State, some of the parameters assessed during the study included average speed of operation, average wheel slip/travel reduction, average draught of implement, and fuel consumption. The cost of operation and yield over five years of usage at Niger State and two years in Kwara State was determined and it was therefore concluded that the power tiller is the most appropriate field machinery for tillage operations such as puddling, leveling on lowland rice production in Nigeria.
文摘西北工业大学濮良贵教授主编、高等教育出版社出版的《机械设计》是一本机械设计领域的经典教材,自出版以来,在很多高校的机械工程相关专业中广泛使用,深受好评和欢迎。本文捡取了该教材中我们认为或论述有问题、或解释不够简明、或没有展开深入解释、或表达有错误的若干问题,从数学角度给予了详细的解释或证明。这些问题是我们在教学实践中感到青年教师和学生理解比较困难、困惑比较多的问题,搞清楚这些问题的理论基础,有利于加深理解教材、提高教学质量。“Mechanical Design”, edited by Professor Pu Lianggui from Northwestern Polytechnical University and published by Higher Education Press, is a classic textbook in the field of mechanical design. Since its publication, it has been widely used in mechanical engineering related majors in many universities and has received high praise and popularity. This article selects several issues from the textbook that we believe have problems with the discussion, lack concise and clear explanations, have not been elaborated and explained in depth, or have errors in expression, and provides detailed explanations or proofs from a mathematical perspective. These issues are difficult and confusing for young teachers and students to understand in our teaching practice. Clarifying the theoretical basis of these issues is beneficial for deepening understanding of textbooks and improving teaching quality.
