Research On Bilateral Teleoperation For Formation Of Multiple Unmanned Aerial Vehicles

Groups of Unmanned Aerial Vehicles(UAVs)are promising in many applications such as large-scale surveillance,safety inspection,and search and rescue missions,which is more effective than a single UAV with complex structure.But due to the complexity and unpredictability of real-world scenarios,complete autonomy of UAVs is hard to reach.At present,a more feasible and effective solution is to adopt a semi-autonomous control method to complete complex tasks under the supervision or auxiliary control of the operator,that is,the multi-UAV bilateral teleoperation control.This paper focuses on the multi-UAV bilateral teleoperation system,studying the establishment of the UAV bilateral teleoperation channels,the energy-optimized consensus formation control and the multi-UAV cooperative transportation method.Firstly,the bilateral teleoperation control framework for the UAV system is studied.In this framework,the position-speed workspace mapping is first used to solve the serious mismatch problem between the dynamics,the workspace and degrees of freedom of the master-slave robot.Secondly,for the time-varying delay between the master-slave side and the slave UAVs,a damping injection P-like controller is proposed to ensure the stability of the time-delayed bilateral teleoperation system.At the same time,the stability is analyzed by the Lyapunov-Krasovskii function and the delay-dependent stability criterion is obtained under the condition of linear matrix inequality.The control framework can establish the UAV bilateral teleoperation channels,and solve the asymmetric time-varying delay control problem of the UAV bilateral teleoperation system.Secondly,the energy-optimized consensus formation control method for the multi-UAV system is proposed.Considering the limited communication and computing resources,an energy-optimized multi-UAV formation control method based on bilateral teleoperation is designed.A distributed consensus formation controller is firstly proposed which enables the slave UAV group to respond to the control commands of the operator in time,and enables the slave UAV group to dynamically adjust the topology according to the environmental conditions.The dynamical topology can avoid collisions between UAVs and between UAVs and obstacles,eventually forming and maintaining a required formation.Then,aiming at reducing the energy consumption of communication link between the UAV groups in the three-dimensional space,an optimal persistent formation generation algorithm based on the 3D optimal persistent graph is proposed.The algorithm uses a top-down 3D optimal persistent graph strategy to optimize the topology of the slave UAV formation.Under the optimized topology with environmental constraints,the slave UAV system can maintain or switch rigid formations permanently,while minimizing communication complexity and energy dissipation,and extending the network life cycle.Lastly,a multi-UAV cooperative transportation control strategy based on the visual and force feedback is proposed.In order to solve the problem of cooperative load transportation,a multi-UAV cooperative transportation control strategy based on the visual and force feedback is designed.The strategy can be divided into two stages of target approaching and load transportation.In the process of target approaching,a cooperative formation control strategy is designed to carry out the tasks such as formation navigation,formation transformation and target approaching in the obstacle environment.In the process of load transportation,a cooperative transport control strategy is designed to enable the transport system to track the operator’s reference speed accurately.Then,in order to improve the operator’s perception of the slave system,three different feedback force cues of speed,force and speed-force are designed,and the evaluation of haptic cueing is carried out by using two criteria of maneuverability and just noticeable difference.Therefore,the operator can obtain better maneuverability and perceptual sensitivity,and further improve the transparency of the bilateral teleoperation system.