Research and development within the windsurfing field is comprised purely of previous experience, prototype building and testing on the water. The use of Computer Aided Design （CAD） systems and simulation packages c...Research and development within the windsurfing field is comprised purely of previous experience, prototype building and testing on the water. The use of Computer Aided Design （CAD） systems and simulation packages can significantly help in the design and testing phases by optimizing the design before a prototype is built. In the paper, supported by these software tools, the authors show a new patented system, named iDO, developed with the aim to stabilize the windsurf, to allow reducing the initial difficulties that a beginner meets in the learning phase. The design process, from the idea to the manufacturing aspects, with all the technical and technological problems, is described. The validation product was carried out by means of user evaluation questionnaires from sixty-four windsurfing beginners in several countries over world. The results show that the users are significantly satisfied with the product.展开更多
The orbits of solar sails can be changed by adjusting the sail’s attitude through external control torques.The resulting momentum will be changed,either provided by a typical attitude control subsystem or by a propel...The orbits of solar sails can be changed by adjusting the sail’s attitude through external control torques.The resulting momentum will be changed,either provided by a typical attitude control subsystem or by a propellantless device.This paper investigates the extra momentum input and fuel consumption for a typical attitude control subsystem.The minimum-time transfer trajectories are designed for two rendezvous missions using both indirect and direct methods,generating continuous and discrete attitude histories,respectively.The results show that the momentum variation is almost wholly due to the solar radiation pressure.The feasibility of using tip-mounted microthrusters for attitude control is evaluated.The results show that less than0.1 kg of propellant are required for an interplanetary transfer mission when pulsed plasma thrusters with a specific impulse of700 s and a thrust of 150 mN are mounted at the tip of a 20 m square solar sail.The fuel consumptions of two transfer missions indicate that a tip-mounted pulsed plasma thruster is a viable technique for the attitude control of a solar sail.展开更多
文摘Research and development within the windsurfing field is comprised purely of previous experience, prototype building and testing on the water. The use of Computer Aided Design （CAD） systems and simulation packages can significantly help in the design and testing phases by optimizing the design before a prototype is built. In the paper, supported by these software tools, the authors show a new patented system, named iDO, developed with the aim to stabilize the windsurf, to allow reducing the initial difficulties that a beginner meets in the learning phase. The design process, from the idea to the manufacturing aspects, with all the technical and technological problems, is described. The validation product was carried out by means of user evaluation questionnaires from sixty-four windsurfing beginners in several countries over world. The results show that the users are significantly satisfied with the product.
基金supported by the National Natural Science Foundation of China(Grant No.11272004)China’s Civil Space Funding
文摘The orbits of solar sails can be changed by adjusting the sail’s attitude through external control torques.The resulting momentum will be changed,either provided by a typical attitude control subsystem or by a propellantless device.This paper investigates the extra momentum input and fuel consumption for a typical attitude control subsystem.The minimum-time transfer trajectories are designed for two rendezvous missions using both indirect and direct methods,generating continuous and discrete attitude histories,respectively.The results show that the momentum variation is almost wholly due to the solar radiation pressure.The feasibility of using tip-mounted microthrusters for attitude control is evaluated.The results show that less than0.1 kg of propellant are required for an interplanetary transfer mission when pulsed plasma thrusters with a specific impulse of700 s and a thrust of 150 mN are mounted at the tip of a 20 m square solar sail.The fuel consumptions of two transfer missions indicate that a tip-mounted pulsed plasma thruster is a viable technique for the attitude control of a solar sail.
