METHOD OF CONTROLLING AN ACTUATOR SYSTEM AND AIRCRAFT USING SAME

A method of operating an under-actuated actuator system including a plurality of actuators (3), preferably for operating a multiactuator aerial vehicle (1), wherein the actuators (3) are individual propulsion units of the multiactuator aerial vehicle (1), each actuator having a maximum physical capacity umax, the method including: controlling the actuators (3) by with an actual control input u∈k computed from an allocation equation u=D−1up, wherein D−1 is an inverse allocation matrix and up∈m is a pseudo control input defined by a system dynamics equation m(x){umlaut over (x)}+c(x,{dot over (x)})+g(x)+G(x)up=fext, wherein x∈n is an n-dimensional configuration vector of the system, m(x)∈n×n is a state dependent generalized moment of inertia, c(x,{dot over (x)})∈n are state dependent Coriolis force, g(x)∈n are gravitational forces and fext∈n are external forces and torques, and G(x)∈n×m is a control input matrix which contains the information of under-actuation. The system is under-actuated if Rank (G(x))<n or both under-actuated and overly determined in case of k>m>n and Rank (G(x)D)<n, with k,m,n∈; using state feedback control to recurrently compute a desired pseudo control input up from the system dynamics equation. If at least one component of the desired pseudo control input up is greater than a corresponding maximum pseudo control input upmax that can be generated based on the actuator maximum physical capacity umax and based on positions (or characteristics and configurations) of the actuators within the system, prioritizing at least one of the components of up over the other components of up; and a) by using a prioritizing algorithm, solving the allocation equation for the at least one prioritized component of up before solving the allocation equation for the remaining components of up; or b) during state feedback control, adjusting a limiting value of the at least one prioritized component of up by an amount, while keeping respective limiting values of the remaining components of up essentially constant.