Design Parameters Optimization And Deployment Experiment Study Of The Rocker-bogie Suspension For Lunar Exploration Rover

Lunar Exploration Rover is an important tool for exploring moon surface. Suspension is the key part of the exploration rover, which connects the body and wheel and bears weight load of the body. Research on key technologies of Lunar Rover has important significance in theory and engineering based on suspension. Rocker-bogie suspension becomes a research emphasis, because it has simple structure and is employed in Mars Rover Sojourner and MER successfully. This dissertation studies on the rocker-bogie suspension from three respects: improving mobility performance of the lunar rover, lightweight design of the suspension, and reducing volume of exploration rover in transmitting state, suspension parameters optimization, structure topology optimization and test of folded suospension are carried out.Design parameters of suspension has greatly influence mobility performance of exploration rover, comprehensive mobility performance of rover can improve by suspension parameters optimization. On the basis of terrain feature of lunar surface, evaluation parameters of mobility performance are presented corresponding to motion conditions of exploration rover. Two representations of design parameters of rocker-bogie suspension are defined. Aiming to the change of center of mass of exploration rover, domain of center of mass is calculated. After analysis overturn, geometric trafficability and mobility placidity, parameterized models of mobility performance are bulding.According to the objective function of motor consumption maximum power during the obstacle negotiation, body vertical displacement and pitch angle in the uneven condition, and as constraint conditions based on overturn, geometric trafficability, mathematical model of parameter optimization is proposed on the basis of parameterized models of mobility performance. Then design parameters of suspension are optimized by SQP, and suspension parameters of deployable suspension are determined. Comparing objective functions in initial and designed values of suspension, the results prove that suspension parameters optimization are effective for improving mobility performance of exploration rover.According to lightweight design of the suspension, taking minimal compliance and maximal natural frequency as objective functions, and volume fraction as constrains, structure topology optimization of suspension is studied from statics, dynamics and combination of statics and dynamics. The best topology structure of suspension is obtained. Taking structure topology contours of volume fraction 0.2 as results, structure size of suspension is determined in the deployable state. According to the FEA, rationality of the structure is verified.For the contradiction between volume of working conditions and launch state, the the rocker-bogie suspension is designed on the basis of the folding characteristics and design requirements. The folding scheme is determined through the fuzzy comprehensive evaluation. On this basis, we designed a new spring-driven folding suspension and analysed the dynamics of expanding process. The study on the first 4-order modals of expanding and folding state is presented. The results show that the acceleration of the body in the expanding progress will significantly reduce while we increase the damp and brake the wheel. Also, the volume of exploration rover is reduced, and the ability of impact resistance is enhanced on the basis of the greatly increased natural frequency.At last, a principle prototype with repeatedly folding-and-unfolding function is manufactured, whose size ratio is 1:2. Then some experiments are done as follows: folding and unfolding experiment, acceleration test experiment in the process of deployment, vibration experiment, et al. The results show that the unfolding function meets the requirement, which verifies the rationality of structure design, and the acceleration change trend is consistent with the simulation result during the suspension deployment, and the natural frequency in the folding state of suspension is larger than that of deployment, which has a good agreement with the result of finite element analysis.