Mechanism Design And Dynamics Analysis On Hopping Robots

Hopping robots can overleap the obstacles or ditches which dimensions are several times than the robots', they are more adaptive for all kinds of terrain. The sudden and eruptible characters of the hopping movement are more adaptive to avoid danger. The hopping robots will have an extensive application in the modern war and the space exploration community. Because of the juvenility of technique, the hopping robots are still in its' developing phase, and there having no hopping robots that can be put into use. The hopping robots include continuous and discontinuous types. The balance of discontinuous hopping robots needn't be kept under control at any time, and meanwhile have the characters of simple structure and higher hopping height. This paper studies the discontimuous hopping robots. Several hopping mechanisms are constructed, and a hopping robot with wheeled mobile ability is builded. Their dynamic problems are analyzed. The most obtained theories can also be applied to continuous hopping robots. Main research achievements of this paper are as following:1. The continuous and discontinuous hopping movement, the continuous and discontinuous hopping robots are compared. The genesis and the present status of their research, the trend of development are summarized. The main methods for hopping mechanism design are summarized. The main problems and the solutions are pointed out. Several hopping robots are introduced.2. Three mechanisms, linear elastic hopping mechanism, six-pole elastic hopping mechanism, six-pole elastic hopping mechanism after modified, are built. Their mechanism designs are given and their working principles are analysed. A robot with wheeled mobile ability and hopping ability is constructed. In the flat environment, the robot moves with its wheels. In the environment with obstacles and ditches, the robot can hop to extend its motion range. The architecture of the robot mechanical system, the structure of the robot body, the hopping stance and the locomotion process are introduced. The hopping mechanical system, the hopping parameter adjusting system, the overturning system, and the buffering system for landing are analyzed in detail, and the mechanism desgin is presented. Some key parameters of the robot are determined according to the requirements of the overall design.3. The basic hopping models, the single DOF spring mass movement system and the double mass spring movement system, are analysed. Three models, linear elastic hopping model, six-pole elastic hopping model, six-pole elastic hopping model added with torsion spring, are built. In modeling, the dynamics of the actuator and all kinds of the damp are considered. The Lagrange formulation approach is used to make the analysis and the comparison. The dynamic state equation of the three hopping models and the hopping height equation are derived. The various elements of affecting the hopping movement are analyzed in details from three aspects: the elements affecting the hopping height, the main reasons of causing energy losing, and the other elements affecting the hopping movement.4. The model of a discontinuous hopping robot is constructed. Its single hopping track is calculated and analyzed. The ellipse composed by culmination of hopping track is described. The track estimating theory is applied to the analytical processes of hopping in the several typical environments: hop over planar surface, overleap obstacles and ditches, jump up steps or jump down. A formula for controlling the hopping robot is given. The formula of cost for evaluating the hopping results is derived. These algorithms are applied to the sequence planning and a hopping sequence planning of the hopping robot is described. Analyzing the spring mass movement system is investigated and the neural network is used to implement for such a movement system. The Multi-Layer-Perceptrons (MLPs) in analyzing this movement system is constructed; the simulation process and result are given. The parameters of the kangaroo and human hopping movement are used to validate the validity of MLPs. Analytical results show that, MLPs are suitable for exact analyse of the fast hopping movement.