Design And Stability Analysis Of Landing Mechanism With Parallelogram Structure For Recyclable Rocket

The majority of current launch vehicles are single-use only. Many countries have been explored the methods to reduce the cost of launching. It appears to be an efficient way to reduce launch cost by achieving rocket recycle after launching with maintenance to fulfill multiple-emission. The huge impact will be generated between the rocket and ground during landing, and even cause instability or rollover. In order to ensure the stability of the rocket landing, it is of great significance to study the landing supporting mechanism of the recyclable rockets is of great significance.Firstly, this paper confirms the number of landing legs and purposes two configuration scheme of the landing legs, namely, the inverted triangle landing mechanism and parallelogram landing mechanism, respectively. The parallelogram configuration is further selected via comprehensive comparison among mechanism feature as well as working principle. The static analysis is carried out by estimating the peak value of impact forces as a constant value acting on the landing mechanism. An optimization model is established by regarding the size parameters as independent variables and the minimum force on lander as the objective function. Matlab optimization toolbox is used to obtain the optimization results to determine the size parameters of landing mechanism.Secondly, a two-dimension landing model is developed by simplifying the landing mechanism based on the structure and dimension parameters. The equation of motion is also analyzed. The numerical results of the system dynamics are obtained in Matlab environment by implementing numerical integration using ode-function to evaluate the landing stability of the rocket.Finally, the simulation of the landing process has been implemented in ADAMS environment by setting different horizontal velocity and attitude angle as initial conditions. The effect of the initial condition including the height, horizontal velocity as well as pitch angle on the landing stability is investigated by contrasting the acceleration responses and the buffer stroke and other simulation results under different working conditions. The parameter region of landing stability is determined by searching algorithm based on the discrete landing parameters.