Design and analysis of a novel hinged boom based on cable drive

Hinged booms are widely used in astrophysics missions;however,the trajectory and deployment velocity are difficult to control because they are usually driven by springs,which limits their application in narrow spaces.Thus,a novel hinged boom is highly required to achieve motion controllability.Through an equivalent substitution between the cable drive loop and the binary link in topology,a type synthesis method for the cable-driven single-degree-of-freedom chain is proposed based on the single-open-chain(SOC)adding method.According to the configuration design,a novel cable-driven hinged boom is proposed,aiming to achieve boom synchronism.Then,to preload easily,a method that preload is applied and measured at the cable ends is adopted and the relationship between the initial preload and the target preload is deduced.By analyzing the distribution of cable tension,a new stiffness model is proposed thus a stiffness equation is obtained.Finally,the dynamic simulation analysis and zero-gravity deployment experiment of the hinged boom is carried out to verify its reliability.This research provides a new way for the type synthesis of cable-driven single-degree-of-freedom chain and a new model for analyzing cable-driven stiffness.Moreover,the novel cable-driven hinged boom obtained in this study can be well-applied in the field of aerospace.

An Underwater Biomimetic Robot that can Swim,Bipedal Walk and Grasp

In developing and exploring extreme and harsh underwater environments,underwater robots can effectively replace humans to complete tasks.To meet the requirements of underwater flexible motion and comprehensive subsea operation,a novel octopus-inspired robot with eight soft limbs was designed and developed.This robot possesses the capabilities of underwater bipedal walking,multi-arm swimming,and grasping objects.To closely interact with the underwater seabed environment and minimize disturbance,the robot employs a cable-driven flexible arm for its walking in underwater floor through a bipedal walking mode.The multi-arm swimming offers a means of three-dimensional spatial movement,allowing the robot to swiftly explore and navigate over large areas,thereby enhancing its flexibility.Furthermore,the robot’s walking arm enables it to grasp and transport objects underwater,thereby enhancing its practicality in underwater environments.A simplified motion models and gait generation strategies were proposed for two modes of robot locomotion:swimming and walking,inspired by the movement characteristics of octopus-inspired multi-arm swimming and bipedal walking.Through experimental verification,the robot’s average speed of underwater bipedal walking reaches 7.26 cm/s,while the horizontal movement speed for multi-arm swimming is 8.6 cm/s.