On Modeling And Subsectional Algorithm Of Underactuator Biped Robot

The study on biped robot have gained an increasing interest in the field of robotics research, during the past twenty years, some universities as well as some distinguished laboratories in the world have paid more attention to the research of this field and have finished some well-known workable models machine, in addition these typical models have great impact on the society and have changed our lives in some field greatly. Also the study on the passive gait biped has attracted so many researchers and it has gradually become the focus of the advanced robotics research.The main idea of the passive dynamics is: to begin with, propose some appropriate passive gait biped model, then establish the corresponding mathematical descriptions of this walking model, in spite of this, to give the analysis of the dynamical property and walking characteristics, and also the arithmetic control strategies to reveal the internal theory of human's high speed and the high efficiency gait biped walking.The focus of the work are a hybrid model for a passive walker with knees presented with numerical simulation and the the research on sub-sectional algorithm of under-actuator biped robot, which can attain to the goal of keeping overall state-space stable control of the kneed biped robot. The main content will be introduced as follows:1) It is well-known that a suitably designed un-powered mechanical biped robot can "walk" down an inclined plane with a steady gait. The focus of the work is a hybrid model for a passive walker with knees presented with numerical simulation. The dynamics and its characteristics of the biped locomotion were analyzed. All the research above have the positive meaning for bridging the gap between existing theoretical models and developing prototype machine. Finally, the 3-d hybrid model for a passive walker with knees was presented and given a simple description.2) The preferences of mass distribution on under-actuator has strong affect on the robot' bipe. The dynamics and its characteristics of the biped locomotion were analyzed based on theory and experiment. An optimizal study on rationality of mass distribution has been done. This thesis also presents the rationality of parameter by the model simulation. All the research above provide the model for the establishment of the gait mode, lay a theory foundation for the analysis of dynamical characteristics.3) An approach so called "sub-sectional control" is presented, which can make the kneed biped robot attain to the goal of keeping overall state-space stable control , and to adapt to the different ground. Based upon the robot's states, two regions were divided based on the walking robot's condition: the internal attraction region and the external one. We present an algorithm in this paper using hybrid strategy to bring the biped back to the basin of attraction with the so-called the domain controller on current estimated slope and thus make it to the reference stable limit cycle. In addition, PD controller working as the transition controller is applied to bring the gait inside the basin of attraction by tracing a planning trajectory, and then switching to energy based slope invariant control.4) Summarizes the application of these techniques to the kneed walker, and gives two sets of simulation to verify the correctness of this algorithm. The initial value of two sets one starting inside the domain of attraction and another outside the domain of attraction. Both the simulation and experimental showed that this approach greatly increases the robustness of the closed loop system to external disturbances and variation in the ground slope attaining the goal of mimicking the gait of human-walking.In conclusion, This paper mainly discuss the modeling of a hybrid model for a passive walker with knees, dynamical analysis and the method of "sub-sectional control". There are many unsolved problem will futher investigation. Such as the 3-d passive based dynamical modeling and theoretical analysis and the perfect of the method of "sub-sectional control".The result of the paper will help to find an important practical application in the design of the robot's gait. This has greatly increased the robustness of the closed loop system to external disturbances and variation in the ground slope attaining the goal of mimicking the gait of human-walking. This is demonstrated by simulations. "Sub-sectional control" will be the new method to make the compass gait biped attain to the goal of keeping overall state-space stable control ,and adapt to the different ground. Future work may involve presents the analysis of stability and robustness of the closed-loop system and application to other practical situations. The resreach on the biped robot finally will realize the arithmetic control strategies to reveal the internal theory of human's high speed and the high efficiency gait biped walking.