The Research Of Motion Control And Simulation Of Legged Robot

Legged robots deserve special attention in both military and civil fields nowadaysby their excellent mobility and adaptability which can let them march and surmountunder various terrains within the public transportation or battle field. The mobility ofrobot largely depends on the mechanism, the drive mode, and the motion controlstrategy. The confirmation of mechanism and drive mode which determines thecontrollable degrees of freedom and controllable variables is before the confirmation ofmotion control. Thus, the mobility mainly depends on the motion control only. In thisthesis, the main objects of research are the single leg robot and four legged robot. Theresearches focus on motion logic, control logic based on the kinematics and dynamicscharacters of each term. The former’s research is based on the SLIP dynamics model,while the latter’s research is based on the quadruped gait model. And the modeling andsimulating of three-dimension mechanistic model are involved for both parts of research.In accordance with these aspects, large amount of experiments about the modelstructure, control method and algorithm simulation were done. There are theachievements below.1. Based on the SLIP model, by using the FSM model, the motion control logic isdesigned. The joint decoupling control is designed to realize the forward speed controland body posture control. The spring energy compensation method is designed to realizethe hopping height control for maintaining the robot motion. In the ultimate experiment,the single legged robot can hop forward stably at the speed of1.2m/s.2. Based on the research of quadruped static gait model, the top-down hierarchicalmotion control logic is designed. Considering the outside environment for applying thestatic gait, the trajectory planning logic with a function of obstacle crossing is designed.According to the drive mode of joint of leg, an approximate dynamics model isproposed by way of parameter linearization to build the joint controller. Based on thebalancing analysis at the COM point of body, a stability criterion of the motion isproposed. In the ultimate experiment, by using static gait, the four legged robot canexplore stably with the stride of0.2m. 3. In this paper, the simulation models of both single leg and four legged robots aredesigned with the SolidWorks, the software for three-dimension mechanical modeling.Among which, the single leg robot has one joint with simulating the electric motor drivemode, while the four legged robot has four legs and twelve joints in all with simulatingthe hydraulic drive mode. The experimental environment is built by the ADAMS, thesoftware for dynamics analysis, and test the motion control designed in this paper byusing the co-simulation with Matlab\Simulink.