Research On The Hysteresis Control Of Artificial Muscles Based On Stochastic Recruitment

With the accelerating development of research in the field of robot control,the controlling direction of the robot actuator has expanded to compliant mechanism drive technology from rigid mechanism gradually.Compared to the rigid mechanism,compliant mechanism has some advantages,such as lower noise,high power density and high degree of freedom,which is close to the ability of the biological muscle.At present,the artificial muscle actuators are the most widely used compliant actuators.But,the materials such as Shape Memory Alloy(SMA),which is the part of artificial muscle actuator,has a certain difficulty in controlling by reason of the intrinsic characteristics of the material itself.Therefore,the study of artificial muscle control has the theoretical and practical significance.This thesis analyzes and researches the key problems of controlling system composed of artificial muscle,which is based on the Stochastic Recruitment strategy.The main works are as follows:Firstly,this article analyzes the controlling mode of SMA from the stochastic recruitment strategy,including the characteristic analysis of artificial muscle actuator materials and the reflection of stochastic recruitment concept in the controlling stage.Then proves the feasibility of binary model through theoretical derivation.Secondly,based on SMA binary control,analyzing the material characteristics by establishing the shape memory alloy mathematical model,and combined the segment binary control and shape memory alloy continuous model by stochastic recruitment,realizing the time-varying control system based on stochastic recruitment binary model in physical significance.Then,proposed and designed the SMA hysteresis loop electric current control system.Adjusting the phase hysteresis loop of SMA materials by different electric current,to improve the phase delay of SMA in phase transition.Making the cellular in the ready state when generating phase transition through transition probability each time,also making the hysteresis loop getting more stable phase transition by binary model.Finally,improving the phase delay according to the electric current.The SMA hierarchical switching controlling system is designed,dividing SMA wire by different dimension to generate various phase changing.Then,discrete event trigger is adopted to acquire the cellular states after phase transition,making the data obtained by the controller parameters more efficiency.Superior controlling effect through simulation experiments is achieved.