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The paper is concerned with the robust finite-time stabilization problem of quadrotors subject to inertia uncertainty and disturbances. The underlying stabilization problem consists of controller designs for position loop and attitude loop, both of which are carried out based on the terminal sliding mode control approach. First, a robust finite-time position controller is designed by considering the...
A novel sensorless speed control algorithm based on sliding mode observer (SMO) for permanent magnet synchronous motors (PMSM) is proposed. By utilizing a phase locked loop algorithm (PLL) based on synchronous reference frame and an embedded low pass filter, the drawback of SMO called “chattering phenomenon” is effectively attenuated, with no phase delay caused by the filter. The active back electromotive...
Standard hexarotors are often mistakenly considered ‘by definition’ fail-safe multi-rotor platforms because of the two additional propellers when compared to quadrotors. However this is not true, in fact, a standard hexarotor cannot statically hover with ‘only’ five propellers. In this paper we provide a set of new general algebraic conditions to ensure static hover for any multi-rotor platform with...
A robust nonlinear adaptive controller design for unmanned autonomous vehicles (UAVs) for controlling the hovering flight is presented. The controller is premeditated recursively based on the control Lyapunov theory where the mass of the UAV in the model is considered as anonymous parameter. To illustrate the forcefulness property of the designed controller, the effects of external disturbances are...
This work deals with the adaptive imbalance force compensation for a three-pole active magnetic bearing (AMB) system. The adaptive compensation scheme utilizes the method of immersion and invariance (I&I) control. In this study, the stabilized three-pole AMB system with known imbalance is considered as the target system. In practical applications, the imbalance force may be unknown and may be...
The quad-rotor pendulum is a multi-variable, nonlinear and non-minimum phase system. There are two main problems considered in controlling the quad-rotor pendulum: one is how to response quickly; the other is to stabilize the quad-rotor pendulum at the expected position. In order to solve these two problems, the Backstepping controller is used to realize it, the simulation results show that the proposed...
A robust feedback position control scheme is presented for quadrotor helicopter in the presence of model parameter uncertainties and external disturbance. Robust position control is guaranteed by disturbance observers designed to estimate model parameters uncertainties and external disturbance. Nonlinear terms in quadrotor model are also viewed as disturbance in disturbance observer design procedure...
A kind of attitude control method for the quadrotor unmanned helicopter based on improved active disturbance rejection control (ADRC) is proposed in this paper. The dynamic model of the quadrotor unmanned helicopter is built, and the virtual control is introduced, then the non-linear model is decomposed into height, yaw, roll and pitch of the four independent channels and the disturbance rejection...
In order to reduce power losses of magnetic bearings in a magnetically suspended control moment gyro (MSCMG), this paper reports the development of a magnetic bearing system that integrates axial repulsive passive magnetic bearing and radial active magnetic bearing. In this paper, modeling of the permanent magnetic for the Halbach structure has been done with the help of magnetic charge method. The...
In this paper, a robust control strategy applying on a small helicopter is proposed. The controller is designed using the backstepping approach based on Lyapunov function. In control design, a hierarchical inner-outer loop based structure is proposed to control the hover flight in the presence of external wind gusts. The outer loop (position control) employs robust backstepping controller to control...
In this paper, a robust altitude control for small RC helicopters near ground surface is proposed. Stable takeoff, landing and hovering near surface are realized by both ground effect compensation and robust sliding mode control which suppresses the modeling error of dynamics and ground effect. To prevent the steady state error induced by the boundary layer which is indispensable to avoid chattering...
This paper describes impact of nonlinearities of the radial force on decentralized control of active magnetic bearings (AMBs). Two cases with different design are analyzed; one with a considerable impact of magnetic nonlinearities, and other with almost linear magnetic properties. The current and position-dependent radial forces are determined by finite element computation over the entire operating...
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