In view of the problem of standoff target tracking and simultaneous arrival of multiple unmanned aerial vehicles (multi-UAVs)

a new ratio Lyapunov vector field (RLVF) and a cooperative speed controller based on τ coupling theory were proposed. First

compared with other Lyapunov vector fields

a settable parameter was added to the new RLVF

so as to balance the convergence speed and heading rate limitation in the tracking process and thus maximize the performance of UAVs. Then

theoretical analysis showed that with smaller parameter

the convergence speed was faster

but the heading angular rate was higher. Besides

the parameter selection method under the limitation of maximum heading angular rate was proposed to realize a faster convergence speed. Finally

in order to ensure that the UAVs can reach the target point from different initial positions at the same time

a cooperative speed controller based on τ coupling theory was designed. Without coping with the actual irregular flight paths

the proposed controller only needs to calculate the straight-line distance from the current point to the target point

avoiding the complicated path integration problem in existing 4D path planning methods

and the algorithm is simpler

which is more conducive to engineering implementation. Results of digital simulation and hardware-in-loop experiment showed that by the proposed method

UAVs could achieve simultaneous arrival and fast convergence to the standoff radius

indicating the effectiveness and superiority of the method as well as its engineering implementation value.