Based on the critical gap phenomenon of the intestinal capsule robot,a variable-diameter capsule robot with radial gap self-compensation is developed in this paper.With the functional variation principle,a fluid dynam...Based on the critical gap phenomenon of the intestinal capsule robot,a variable-diameter capsule robot with radial gap self-compensation is developed in this paper.With the functional variation principle,a fluid dynamic pressure model satisfying the boundary conditions of the outer surface of capsule robot with screw blades is derived.The critical gap phenomenon is studied theoretically and experimentally based on the end effect and the dynamic balance characteristics of the fluid on the surface of capsule robot.The concept of start-up rotation speed is defined,the relationship between the start-up rotation speed and the spiral parameters of capsule robot is investigated.The strategy for implementing drive and control on several capsule robots under the same rotational magnetic field is proposed,and by defining the start-up curves of several capsule robots with the similar motion regulation as the objective functions,genetic algorithm is employed to optimize the spiral parameters of several capsule robots.Experiments have shown that the proposed drive and control strategy for several capsule robots can be implemented effectively.It has a good prospect of application inside intestine to realize the drive and control on several capsule robots for different medical purposes.展开更多
There is a growing interest in propellers for transport aircraft as well as regional airliners from the viewpoint of energy saving. An important consideration for utilizing a propeller propulsion system on aircraft is...There is a growing interest in propellers for transport aircraft as well as regional airliners from the viewpoint of energy saving. An important consideration for utilizing a propeller propulsion system on aircraft is the aerodynamic interaction between the propeller slipstream and other aerodynamic surfaces. It is therefore necessary to use a simplified but relatively accurate tool for propeller modeling, with the widely used actuator disk model. The advantage of this model is that it is easy to use and inex- pensive in terms of computation time required. In addition, it also produces acceptable results. In this study, a new regionalized actuator disk model was utilized in the analysis of propeller slipstream interference effects on a real four-propeller aircraft. The results are compared with the cases of inactive actuator disks, which shows that the propeller slipstream causes an increase in the lift and drag coefficients. An evident yawing effect caused by the rotating slipstream was noticed, which should be taken into account in the design phase. The regionalized actuator disk model is evaluated as a fast and relatively accurate model for propeller preliminary design.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos. 60675054, 60875064)Self-Planned Task of State Key Laboratory of Robotics and System (HIT) (Grant No. SKLRS200903B)
文摘Based on the critical gap phenomenon of the intestinal capsule robot,a variable-diameter capsule robot with radial gap self-compensation is developed in this paper.With the functional variation principle,a fluid dynamic pressure model satisfying the boundary conditions of the outer surface of capsule robot with screw blades is derived.The critical gap phenomenon is studied theoretically and experimentally based on the end effect and the dynamic balance characteristics of the fluid on the surface of capsule robot.The concept of start-up rotation speed is defined,the relationship between the start-up rotation speed and the spiral parameters of capsule robot is investigated.The strategy for implementing drive and control on several capsule robots under the same rotational magnetic field is proposed,and by defining the start-up curves of several capsule robots with the similar motion regulation as the objective functions,genetic algorithm is employed to optimize the spiral parameters of several capsule robots.Experiments have shown that the proposed drive and control strategy for several capsule robots can be implemented effectively.It has a good prospect of application inside intestine to realize the drive and control on several capsule robots for different medical purposes.
基金supported by the Key Projects in the National Science&Technology Pillar Program during the Eleventh Five-Year Plan Period(Grant No.2009BAG12A01)
文摘There is a growing interest in propellers for transport aircraft as well as regional airliners from the viewpoint of energy saving. An important consideration for utilizing a propeller propulsion system on aircraft is the aerodynamic interaction between the propeller slipstream and other aerodynamic surfaces. It is therefore necessary to use a simplified but relatively accurate tool for propeller modeling, with the widely used actuator disk model. The advantage of this model is that it is easy to use and inex- pensive in terms of computation time required. In addition, it also produces acceptable results. In this study, a new regionalized actuator disk model was utilized in the analysis of propeller slipstream interference effects on a real four-propeller aircraft. The results are compared with the cases of inactive actuator disks, which shows that the propeller slipstream causes an increase in the lift and drag coefficients. An evident yawing effect caused by the rotating slipstream was noticed, which should be taken into account in the design phase. The regionalized actuator disk model is evaluated as a fast and relatively accurate model for propeller preliminary design.
