Research On Optimization Design And Combination Gait Of An Aquadruped/biped Walking Robot With Parallel Leg Mechanisms

Along with the rapid aging of the population and the increasing population of thedisabled, the popularity of the walking robot used for the elderly and disabled will behelpful for the happiness of the family and the harmonious development of the society.This paper researches on a reconfigurable quadruped/biped walking robot with parallelmechanism which is used as an instrument riding instead of walking for the elderly andthe disabled. The robot combines the advantages of the lower environment demand of thelegged walking robot, the good stability of quadruped walking robot, the little gradient ofbiped walking robot when walking up and down the stairs, the easy inverse solution andhigh carrying capacity of the parallel mechanism.First of all, the paper takes the biped walking robot with parallel leg mechanism asresearch subject and analyzes the movement characters of the 6-SPU parallel mechanism.Using the parallel mechanism theory and influence coefficients theory, the displacement,velocity and acceleration of mechanism is analyzed. The kinematics model of the 6-SPUparallel mechanism is established. And the model’s correctness is verified by a numericalexample.Secondly, the dexterousness, minimum velocity and carrying capacity of thequadruped and biped walking robot with parallel leg mechanism are researched. UsingMATLAB program platform, each performance index maps are plotted. The relationshipbetween performance indexes and structural dimensions of the robot is analyzed. Then theoptimum numeric area of every dimension is obtained.Thirdly, the leg mechanisms’workspace area of quadruped and biped walking robotare used as the objective function. Based on the optimum numeric area of every dimension,the structural dimensions of the robot are optimized by the method of genetic algorithm.Finally, according to the static walking theory of the quadruped robot, thecombination gaits from the quadruped to biped walking robot are put forward. Using theworkspace of the quadruped robot bodies and the leg mechanism of quadruped robot, thecorrectness of all the combination gaits is verified. By contrasting the stability margin, body adjustment harmony and the shortest moving distance of the body’s centre of gravitywhen the robot works in different combination schemes, the optimum gait is selected.