Research On Control Method Of Obstacle Stepping Dynamically Based On Humanoid Robot With Propulsion System

When humanoid robot performing the tasks such as exploration or rescue in the extreme environments after earthquake,the unpredict factors will occur including large obstacles or ditches.In such situations,it is important for the humanoid robot whether has the capacity of stepping.In this article,to improve the capacity of stepping,we will focus on the realization of dynamic stepping.We proposep the planning method and full-body controller based on the balancing model of biped robot with propulsion system.Main points could be seen as follows:(1)We analysed the dynamic equations of biped robot with propulsion system then gave the definition of dynamic stepping.(2)We proposed the assumptions and introduced the balancing model of biped robot with propulsion system.Based on the model,we further introduced the postural planning problem.Then based on the assumptions,smoothness,reproducibility and hardware,we also introduced the relative constraint conditions.To simplify this problem,we divided it into two phases including initial and middle phase.Then we proposed different methods for each phase based on differential evolution,line search and grid search.(3)According to the model,we also could draw a conclusion that there were some disadvantages when keeping balance only by controlling thrust in vertical direction.And we proposed the full-body controller which was consisted of thrust controller and Co M position controller.For the thrust controller,we proposed the method of controlling the direction and value of thrust in 3D space and its impressions.For the Co M position controller,excepted for the imperssions,we also introduced the idea that how to realize the adjustment of Co M position.Based on the phototype robot,we further proposed the control diagram of the full-body controller.(4)In order to prove the validity of the posture planning method and full body controller,simulations and experiments were designed which could be divided into three parts.In the first part was to verify whether the full body controller could compensate the error of model;in the second part was to verify whether the robot with full body controller could keep stable when suffering the disturbances;in the third part we designed the complex motions including tip-toe rotation and large ditch stepping motion,the general performance of planning method and full-body controller would be tested.Simulations and experiments above were well conducted and have distinct results which proved the validity of our planning method and full-body controller and the realization of dynamic stepping.Particularly,experiment shown that the robot could stepping over a large ditch and its distance was about 147% of single leg's length.Results in simulation also indicated that the robot could performed the large ditch stepping motion dynamically.In addition,the time used was about 3.2 seconds for one step and the acceleration was similar to human when walking.