Dynamics Analysis And Control For UAV Rope-Hook Recovery

Accurate fixed-point non-destructive recovery technology is the key technology to restrict fixed-wing UAV to ship and to adapt to complex areas.Rope-hook recovery technology is an advanced technology which can realize precise fixed-point and non-destructive recovery of small fixed-wing UAV in land-based/sea-based static,dynamic platforms and their narrow space.UAV rope-hook recovery process is essentially a complex non-linear dynamic problem,and an effective dynamic model must be established to obtain accurate response.Firstly,based on Lagrange dynamic equation,a fixed damp dynamic model of rope-hook recovery is established,and its accuracy is verified by comparing with similar literature models.On the basis of the approximate dynamic model,the design parameters of each recycling system are explored,and useful reference is provided for the overall design of the recycling system.Secondly,based on MSC.ADAMS platform,a multi-body dynamic model of rope-hook recovery is established.Both model prove that the fixed damp rope-hooks device has the defects of high peak overload and rapid change of overload.Then,in order to improve this defect,considering the controllable damping force of the rope hook recovery system,a dynamic model of variable damping recovery is established on the basis of the fixed damping recovery model.Based on the Gauss pseudo-spectral method,the optimal control is calculated with the objective function of minimum acceleration change rate and minimum interception resistance.The results show that the peak value of recovery overload of UAV is significantly reduced.It can be seen that the Gauss pseudospectral method has a good off-line optimization effect for this problem and can be used as the optimal planning value.Finally,in order to realize the optimal planning value online,the LQR is used to control the decoupled system by feedback linearization and simulation.Then the feedback tracking method is further extended to the multi-body dynamic model,and the joint simulation of MATLAB/ADAMS is carried out.The simulation results show that most of the planning results are retained.Compared with the fixed damping system,the variable damping system has the advantages of smaller overload peak value and higher recovery efficiency.It shows that the damping force control of the rope-hook recovery system can significantly reduce the peak value of recovery overload and overload drive,which is conducive to improving the safety and stability of UAV recovery.