It is well known that complete attitude control of a spacecraft is not possible with only one single-gimbal Variable-Speed Control Moment Gyro (VSCMG) due to the conservation of the angular momentum. However, partial attitude control without violating the angular momentum conservation principle is still possible. In this paper, feedback controllers that stabilize the angular velocity vector of ...

AIM to investigate knowledge, attitude and behaviour toward infection control in two teaching hospitals on the island of Java by means of a questionnaire and to evaluate the use of the questionnaire as a tool. METHODS we investigated knowledge, attitude and behaviour toward infection control in two teaching hospitals on the island of Java by means of a questionnaire to identify problem areas,...

The unit quaternion is a pervasive representation of rigid-body attitude used for the design and analysis of feedback control laws. Often, quaternion-based feedback control laws require an additional mechanism that lifts a continuous attitude trajectory to the unit quaternion space. Lifting mechanisms that are memoryless, for example, selecting the quaternion having positive scalar component, h...

A novel approach is proposed for the attitude stabilization and reorientation of an axi-symmetric spacecraft subject to two gas jet actuators. The approach is based on a new formulation of the attitude kinematics. Abstract| In this paper we consider the problem of attitude stabilization of an axi-symmetric spacecraft using two pairs of gas jet actuators. These actuators provide control torques ...

This paper constructs a relationship between attitude and translational movement of a quadrotor, and presents a PD logic tracking control design algorithm capable of not only stabilizing attitude but also tracking a desired trajectory accurately. In contrast to conventional flight control systems, the artificial inner/outer-loop structure is eliminated via using a third-order time optimal track...

An integrated coupled control strategy for a servicing spacecraft autonomously approaching and docking with a freely tumbling target is studied. To implement capturing successfully, the docking port of the servicing spacecraft should be always pointing to the docking port of target during close rendezvous and docking, which involves proximity maneuvering of coupled position and attitude simulta...

OBJECTIVE In this study the changes in attitude of midwives towards their work following completion of the Maternal Care Manual of the Perinatal Education Programme (PEP), were determined. METHOD A prospective, controlled trial was performed in a study, and two control towns in a region where PEP had not previously been used. All midwives caring for pregnant women in the three towns were incl...

Due to their size, small rotorcraft are vulnerable to external flow disturbances that are challenging to flight stability and control. This paper describes preliminary results from using onboard flow measurements to augment inertial sensors for attitude control. We derive a dynamic model that captures the aerodynamic effects of wind on a single degree-of-freedom tandem-rotor test stand. A pair ...

Existing position controllers for VTOL UAVs require measurements of the system attitude (orientation) for feedback. However, in practice the orientation cannot be measured directly; it is rather obtained through the use of an attitude observer relying on a set of inertial vector measurements. In this paper a new control strategy is proposed for VTOL-UAVs which avoids the direct measurement of t...