The Cooperative Control Of Nonholonomic Multi-robot Systems Based On Event-triggered Control

In the wave of artificial intelligence,the cooperative control for nonholonomic multirobot systems(MRSs)has been a hot topic,and permeated through all fields of human society,such as formation control,forest fire detection,unmanned reconnaissance system.The limited energy resource is an significant factor to be considered in cooperative control.The event-triggered control approach has attractive superiority on resource utilization,which can effectively reduce the update frequency of the controller and unnecessary waste.In this paper,based on event-triggered control,several cooperative control problems for nonholonomic MRSs are investigated.The main results are as follows:1.The energy-optimal problem for nonholonomic MRSs are studied.In order to avoid collision when rendezvous is achieved,the coordinate transformation is used to transform the centre consensus problem into the hand position consensus problem.In this way,the dynamics of the hand positions for nonholonomic robots are formulated as two groups of first-order linear systems.Assume that each robot has a local cost function that shows the energy consumption in the movement process and only relies on the state of hand position.The distributed event-triggered optimization algorithm is designed such that the states of robots' hand positions exponentially converge to the optimum of the global cost function.Meanwhile,the velocity and orientation of each robot are ensured to reach zero and a certain constant,respectively.Finally,a simulation example is given to verify the effectiveness of the obtained theoretical results.2.The finite-time consensus problem for chained-form nonholonomic MRSs with external disturbances is investigated.Assume that the external disturbances are bounded,and the upper bounds are known positive constants.In order to deal with the coupled term of the chained-form nonholonomic MRSs conveniently,the system is divided into two subsystems including one first-order subsystem and one second-order subsystem,and the controller switching time is introduced to control the subsystem in stages.The integral sliding mode-based event-triggered control laws are proposed to ensure that the states of the robots achieve consensus in finite time in spite of external disturbances.Finally,the feasibility of the integral sliding mode-based event-triggered control laws is verified by a simulation example.3.The finite-time consensus problem for chained-form nonholonomic MRSs with external disturbances of unknown upper bounds is considered.Based on the above work,assume that the upper bounds of external disturbances are unknown positive constants.First,the adaptive mechanisms are designed to estimate the unknown upper bounds online.Second,by defining the triggering functions which associate with the adaptive mechanisms,the integral sliding mode-based event-triggered control protocols are proposed.It can be shown that all states of the system achieve consensus in finite time.Finally,a numerical simulation is presented to illustrate the effectiveness of the theoretical results.