On The Modification Of Kinetic Energy Shaping For Gait Regulation And Chaos Control Of Passive Dynamic Walking Biped Robot

Passive dynamic walking (PDW) biped robot has much higher energy efficiency, and more human-like walking ability than other biped walking robots. Nowadays the research on it has become one of hot points in the field of biped robots. For the gait regulation problem of PDW, increasing the walking speed of the PDW biped robot with the PDW characteristics, many control methods have been proposed. One of such method is named as kinetic energy shaping method.Chaotic behaviors have been found in many nonlinear dynamic systems. As a typical strong nonlinear dynamic system, chaotic behaviors can also arise from the PDW biped robot. In most cases, chaotic behaviors will cause the walking failure and is harmful to the PDW biped robot system. Therefore, some measures should be taken to suppress the chaotic gait and prevent the robot from falling down. That is chaos controlling. On the other hand, recent studies show that the chaotic gait could be found in human walking locomotion, so chaos excitation, or namely chaos anti-controlling, of PDW biped robot has attracted many attention. In summary, the chaos controlling and anti-controlling is one of the most important issues for the design of PDW biped robot.In this thesis, the kinetic energy shaping method for PDW biped robot is investigated and improved. The main research work and conclusions are as follows:1. Based on the extended study of the kinetic energy shaping method oriented to PDW biped robot, modification of kinetic energy shaping method for PDW biped robot is proposed by adding the initial phase into the controlled kinetic energy constructor function. So a new construction way of the constructor function is obtained. The improved kinetic energy shaping method is studied and used throughout entire thesis.2. For the gait regulation problem of PDW biped robot, the best initial phase value of the constructor function is found by exhaustive method. The numerical simulation result shows that the improved kinetic energy shaping method could make the robot walking faster than the existing kinetic energy method with the same constructor function magnitude. The issues, such as the relationship between the magnitude of slope angles and the best initial phase value, the influence of the constructor function initial phase as well as the bifurcations phenomenon in the controlled robot are investigated.3. For the chaos controlling and anti-controlling of PDW biped robot, the best initial phase value and magnitude of the constructor function are determined in the energy point of view. And the kinetic energy shaping method is successfully applied to chaos controlling and anti-controlling of PDW biped robot. It is demonstrated by the results of simulation. In addition, the advantages and disadvantages of using the kinetic energy shaping to control and anti-control chaos of the PDW biped robot is discussed. The difference between the parameters values for the chaos controlling/anti-controlling and the gait regulation of the PDW biped robot is also discussed.