Deployment Dynamic Modeling and Driving Schemes for a Ring-Truss Deployable Antenna

Mesh reflector antennas are widely used in space tasks owing to their light weight,high surface accuracy,and large folding ratio.They are stowed during launch and then fully deployed in orbit to form a mesh reflector that transmits signals.Smooth deployment is essential for duty services;therefore,accurate and efficient dynamic modeling and analysis of the deployment process are essential.One major challenge is depicting time-varying resistance of the cable network and capturing the cable-truss coupling behavior during the deployment process.This paper proposes a general dynamic analysis methodology for cable-truss coupling.Considering the topological diversity and geometric nonlinearity,the cable network's equilibrium equation is derived,and an explicit expression of the time-varying tension of the boundary cables,which provides the main resistance in truss deployment,is obtained.The deployment dynamic model is established,which considers the coupling effect between the soft cables and deployable truss.The effects of the antenna's driving modes and parameters on the dynamic deployment performance were investigated.A scaled prototype was manufactured,and the deployment experiment was conducted to verify the accuracy of the proposed modeling method.The proposed methodology is suitable for general cable antennas with arbitrary topologies and parameters,providing theoretical guidance for the dynamic performance evaluation of antenna driving schemes.

Design and Prototype Test of 9FQM1000 Branch and Straw Hammer Mill

[Objectives]To better design and test 9FQM1000 branch and straw hammer mill in view of the problems of large output,low utilization rate,traditional incineration and easily polluting environment of the new agricultural economic organization's straw and waste branches.[Methods]This hammer mill adopts dual-channel feeding method.It adopts the basic working principle of disc shredding and hammer crushing.Besides,it makes design of the structure and driving system of the branch and straw hammer mill.9FQM1000 type branch and straw hammer mill can finely crush the branches and straws.Finally,it makes a trial production of 9FQM1000 type branch and straw hammer mill.[Results]The prototype test showed that the combined crushing structure of 9FQM1000 type branch and straw hammer mill is reliable,and the production capacity is 3000 kg/h.[Conclusions]The automatic feeder makes the crushing operation more stable,the labor intensity is reduced,the structure is simple,and it can be moved by traction.It is environmentally friendly and pollution-free.It has the characteristics of high safety,automation and high production efficiency.Also,crushed materials can be used as edible fungus culture medium,animal feed,organic fertilizer,etc.,and can be further compressed into biomass fuel,and the crushed branches can also be returned to the field.