Leg Design And Control Research Of Legged Robot Based On SEA

With good environmental adaptability and motion flexibility, Bionic and legged robot can walk stably in uneven environment and undertake dangerous missions, which makes legged robots have broad application prospects in the future. Using force-controlled actuator and control algorithm to control joint force is very important for robot walking stably in uneven environment. Because of incompatible problems of force/energy density and output impedance of the traditional rigid actuators, the thesis selects series elastic actuators(SEA), a force-controlled actuator, based on that SEA has the bionic structure and very good buffer effect on the impact load. Therefore, selecting SEA as joint actuators and carry on a control research on single leg drove by SEA, has important practical significance.The thesis select hydraulic SEA single leg as the research object, through the methods of virtual prototype and experiment, to study force and impedance control characteristics on SEA joint and single leg.First of all, design a elastic element using the finite element method, and measure stiffness of the elastic element with stiffness measurement platform. On this basis, by choosing appropriate sensor and hydraulic actuator, designing transmission mechanism, the SEA joint structure is completed. Under the premise of ensuring the dof configuration and work space, the single leg is completed.Secondly, based on the SEA joint kinematics model to establish a joint torque servo algorithm, after establishing simulation simplified model of the hydraulic actuator, analyze the joint force servo algorithm through the method of virtual prototype simulation. On this basis, the impedance control of the SEA joint is simulated. Based on SEA joint force and impedance control research, the single leg force and impedance simulations are carried on.Finally, after establishing single leg experiment platform, through experiment research, study the characteristics of force and impedance control of the SEA joint and the single leg, verify the validity of simulation results. For simulating legged robot working in uneven environment, design a experiment where robot foot have a impact with ground, to inspect the stability of the single leg system.