Research On Trajectory Tracking Of Aerial Fire Fighting Vehicle Based On Dynamic Sliding Mode Control Theory

Aerial fire fighting vehicle is bound to improve its quantity and quality with the rapid development of the city and the continuous increasein the number of high-rise buildings.As a kind of comprehensive and special equipment for fire protection and rescue of high rise buildings,it is necessary to have a good trajectory tracking performance if we want to realize aerial firefighting vehicle work quickly,smoothly and accurately according to the desired trajectory in space.Because of the characteristics of multi arm section,variable section,large arm length and complex work environment,modeling errors and external disturbances of the boom system will seriously affect the tip trajectory tracking accuracy and tracking performance of the aerial firefighting vehicle.By establishing a complete dynamic model of the boom system,designing dynamic sliding mode controller,and combine with a new arm section deformation compensation method,the trajectory tracking control of aerial fire fighting vehicle boom system is realized with strong robustness in this paper.Research work of this paper includes the following contents:Firstly,the present research and development situation of aerial fire fighting vehicle and related engineering manipulator are analyzedincluding the development of products and technology at present situation.And the modeling of engineering manipulators,vibration control,trajectory planning,trajectory tracking,and correlation study of deformation compensation are reviewed in detail.Secondly,the complete dynamic model of aerial fire fighting vehicle boom system is established in this paper.Considering the joint friction and cylinder hinge point position,the author deduce the complete dynamic model of the arm mechanical system and hydraulic system,and get the control signal for the input and output variables for the joint relationship,which laid the foundation for the design of the controller.Furthermore,first order and second order sliding mode controller are designed based on dynamic sliding mode control theory.The sliding mode control theory is introduced to the trajectory tracking control of aerial fire fighting vehicle,due to the modeling errors and external disturbances on the tracking.Based on the analysis of the basic principle of sliding mode control and sliding mode control characteristics,first order and second order sliding mode controller based on dynamic sliding mode control theory are designed for each joint trajectory tracking.Verifying and comparing control performance and control effect of two kinds of control methods after the analysis of simulation results and comparison of different levels interference effect on trajectory tracking.Finally,a quick and simple method to compensate the deformation of the boom is proposed in this paper.Based on APDL modeling,aerial fire fighting vehicle working space discretization and three spline function fitting,we get the deformation function under any angle and any arm length obtained by an interpolation.Using the desired angle and deformation function to correct the desired trajectory,we get the control method of dynamic sliding mode trajectory tracking based on deformation compensation with the combination with dynamic sliding mode control.