Research On Attitude Estimation And Control Of Attached Lifting Scaffold

The attached lifting scaffold is a kind of multi-node synchronous lifting aerial work platform for construction.At present,the balance degree of the frame operation is judged and controlled synchronously mainly through the position load of each node.In the whole lifting process,due to the motor operation is not synchronous,external resistance,wind load and other factors,the frame may appear horizontal height difference and internal and external tilt.Therefore,the use of load limits can only ensure the basic operation safety of the scaffolding body,can not effectively supervise the whole operation process of the scaffolding system,and can not meet the needs of construction safety and intelligence.In this paper,MEMS inertial measurement unit is used to estimate the attitude of scaffolding system operation,reflecting the state changes of scaffolding.Based on this,the strategy of synchronous control of operation is studied,so as to improve the ability of monitoring and controlling the running state of scaffolding.The main work is as follows:(1)Through the analysis of the structure and principle of the attached lifting scaffold,the attitude data acquisition scheme is determined,the coordinate system and attitude Angle in the attitude estimation of the scaffold are defined,and the relevant model is established after the analysis of the working principle and characteristics of the MEMS inertial sensor.(2)The extended Kalman filter(EKF)was used for data fusion of MEMS inertial measurement unit.Considering that the noise in the system which cannot be updated by EKF would cause attitude estimation error,the time-varying noise was updated by Sage-Husa extended Kalman filter(SHEKF)to improve the accuracy of attitude information.In order to solve the divergence problem of SHEKF filtering,an improved Sage-Husa extended Kalman filter(ISHEKF)is proposed.That is,when determining whether the filtering is divergent by using covariance matching technology,the real-time motion speed of the scaffold is introduced into the regulating factor of filtering divergence decision to improve the judgment basis of filtering divergence.Thus,the covariance matrix can be updated adaptively when the frame is running and the filter divergence can be suppressed.Simulation results show that the ISHEKF algorithm can effectively reduce the degree of filter divergence and obtain high precision attitude information,which provides a foundation for the realization of the operation control of scaffolding.(3)Research synchronous operation control strategy based on attitude information.In order to reduce the synchronization error between each node,a multi-node fuzzy PID error coupling control structure was designed,and the fuzzy sliding mode control algorithm was further used for the operation of single node,which reduced the chattering caused by sliding mode control and improved the precision of position tracking.The simulation results show that the fuzzy sliding mode control algorithm can improve the tracking accuracy of single node by 76.5%compared with PID control,and the fuzzy PID deviation coupling control structure can reduce the synchronization error of about 70%between each node,which proves that the designed control strategy has good control accuracy and synchronization.(4)The operation attitude estimation and control experiment was carried out on the scaffold sample.In the attitude estimation experiments under static and dynamic conditions,the ISHEKF algorithm shows good filtering accuracy and stability,and can accurately reflect the attitude change of the scaffold.In the operation synchronization control experiment,the designed control strategy has good performance both in ensuring synchronous operation between nodes and in restoring synchronous operation after interference.Experimental results show that the proposed algorithm and control strategy are feasible in practice and have application value in condition monitoring and control of attached lifting scaffold.