Fractional Order Control methods were applied to a three-axis reaction wheels satellite attitude control system. To show the advantages of this method, a comparative study between a Linear Quadratic Regulator and a Fractional Order Control was established through two principal fractional control laws. The aim is to establish an efJicient control law which satisJies a given speczjication and mai...

A control scheme for the coordinated control of a Sub-sea vehicle/manipulator system is presented. The unit quaternion representation is used in a singularity free representation of the attitude. The control scheme is formulated in a 12 d.o.f. task space and only position measurements are required. The performance is evaluated by simulation with a realistic model of a commercial underwater vehi...

The tethered space robot (TSR) is a new concept of space robot which consists of a robot platform, space tether and operation robot. This paper presents a multi-objective optimal trajectory planning and a coordinated tracking control scheme for TSR based on velocity impulse in the approaching phase. Both total velocity impulse and flight time are included in this optimization. The non-dominated...

This paper investigates the attitude tracking problem for rigid spacecraft. An adaptive backstepping sliding mode control law is proposed to solve this problem in the presence of inertia uncertainties and external disturbances. The control scheme is developed by combining sliding mode control with adaptive backstepping technique to achieve fast and accurate tracking responses. The proposed cont...

Typically, unmanned aerial vehicles are underactuated systems i.e., they have fewer independent control inputs than degrees of freedom. In a helicopter for example, the body-axis roll, pitch, yaw and altitude axis are fully actuated. However, lateral and longitudinal translational motion is only possible by tilting the thrust vector. This chapter develops a 6 degree-of-freedom flight control al...

An adaptive control algorithm for the spacecraft attitude tracking problem when the spin axis directions and/or the gains of the flywheel actuators are uncertain is developed. A smooth projection algorithm is applied to keep the parameter estimates inside a singularityfree region and avoid parameter bursting. Numerical examples show that the controller successfully deals with unknown misalignme...

Complete attitude control of a spacecraft is not possible with only one single-gimbal variable-speed control moment gyro due to the conservation of angular momentum. However, partial attitude control without violating the angular momentum conservation principle is still possible. In this paper feedback controllers using only one singlegimbal variable-speed controlmoment gyro are presented that ...

This paper presents a method for on-orbit calibration of photodiodes for sun sensing in an attitude determination system. The calibration estimates the scale factors and alignment angles of the photodiodes, resulting in higher attitude determination accuracy than achieved with the pre-flight calibration parameters. The calibration is implemented with an extended Kalman filter to simultaneously ...

We apply retrospective cost adaptive control (RCAC) to spacecraft attitude control with magnetic actuators. We compare two approaches to address the rank deficiency and time-varying nature of the input matrix. The first approach utilizes an average of the magnetic field based on a-priori knowledge, whereas the second approach uses three multi-input, single-output controllers. RCAC uses no infor...

Near-minimum-time attitude maneuvers of space structures as well as ground-based test articles are considered. The switching nature of the controls for rigid-body maneuvers is illustrated using a control cube and a critical control axis. The presence of torque smoothing and, where appropriate, gravitational effects and connections to other bodies are explicitly included in the mathematical mode...