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The purpose of this paper is to design an electromechanical actuator which can inherently tolerate a stuck or loose failure without any need for fault detection isolation and reconfiguration.

Generalized design methodology for a thrust vector control application is adopted to reduce the design iterations during the initial stages of the design. An optimum ball screw pitch is selected to minimize the motor sizing and maximize the load acceleration.

A high redundancy electromechanical actuator for thrust vector control has lower self-inertia and higher reliability than a direct drive simplex configuration. This configuration is a feasible solution for thrust vector control application because it offers a more acceptable and graceful degradation than a complete failure.

Future work will include testing on actual hardware to study the transient disturbances caused by a fault and their effect on launch vehicle dynamics.

High redundancy electromechanical actuator concept can be extended to similar applications such as solid motor nozzle in satellite launch vehicles and primary flight control system in aircraft.

High redundancy actuators can be useful in safety critical applications involving human beings. It can also reduce the machine downtime in industrial process automation.

The jam tolerant electromechanical actuator proposed for the launch vehicle application has a unique configuration which does not require a complex fault detection isolation and reconfiguration logic in the controller. This enhances the system reliability and allows a simplex controller having a lower cost.

Fault tolerant control surface actuation of unmanned aerial systems with take-off weights below 150 kg offers new design challenges due to limitations in mass, weight and cost. Conventional redundancy concepts need to be amended by smart operational strategies, enhanced sensor data provision and advanced failure mitigation. The paper aims for the design of a hardware-in-the-loop platform that enables the model-based development, verification, performance analysis and safety assessment of redundant and smart electromechanical actuators.

The hardware-in-the-loop platform was developed on the basis of various requirements and upcoming certification needs. One major aspect is the close relationship between model-based design approaches and the ability to keep hardware prototypes in the loop during the entire development process using virtual actuator control electronics.

The platform has proven to deliver valuable results during development of hardware and software prototypes. By its high flexibility and modularity, it has shown to be a versatile, attractive and cost-efficient alternative to conventional hardware-in-the-loop environments.

The presented simulation environment allows operating the components under realistic conditions by offering a control surface setup with redundant electromechanical actuators and a torque machine for hinge load simulation. It supports active–active, active–passive and single actuator operations to examine force-fighting phenomena, performance measurements and the exposure to actuator and control surface hardware faults.

The presented simulation environment provides precise knowledge about the behaviour of all involved components within all states of flight as well as mission and failure scenarios that are required during design, implementation and testing of fault tolerant actuation systems.

Reports on the MSc group design project of students at the College of Aeronautics, aerospace vehicle design in 1995. The students worked on advanced short take‐off and vertical landing of a combat aircraft. Details the project showing aircraft dimensions and design. Full assessment of the results is pending, but outlines a number of problems faced by the students.

THE continuing development of aircraft operational concepts has in recent years resulted in the emergence of a variety of flight control functions which are essential to the safety of the aircraft and which moreover have to be performed automatically, the task being either too difficult for the human pilot, or at least so difficult as to command so much of his attention that his ability to carry out other functions is impaired. Among these functions may be instanced automatic landing, autostabilisation of V.T.O.L. aircraft in the hovering flight mode, the autostabilisation of an aircraft in some part of the flight regime in which its own natural stability is negative, and the autopiloting of aircraft operating at extremely low relative altitudes, to avoid collision with the terrain.

This paper aims to address the spacecraft attitude control problem using hybrid actuators in the presence of actuator saturation, uncertainties and faults, inertia uncertainties and external disturbances.

A hybrid actuator configuration is used where thrusters are engaged for rapid attitude maneuvers, while reaction wheels (RWs) are used for fine pointing.

The key advantages are two-fold: a finite-time high-level controller is designed to produce the three-axis virtual control torques; an online robust control allocation (RobCA) scheme is proposed to redistribute virtual control signals to the actuators with taking into account the actuator saturation, uncertainties and faults; and the RobCA scheme allows a smooth switch between thrusters and RWs, which handles the inaccuracy problem of thrusters and saturation problem of RWs.

An online RobCA algorithm is designed that maps the total control demands onto individual actuator settings and allows a smooth switch between thrusters and RWs. Simulation results show the effectiveness of the proposed control strategy.

This work may be used on modern space missions, which impose higher requirements on smooth switching of spacecraft thrusters and RWs.

In the past electromechanical actuators have been used to operate and control functions that demanded reasonably low power whilst the more arduous requirements of secondary and primary flying control surfaces have been powered by hydraulic motors and drives. With the advent of rare earth permanent magnet electrical machines with greatly enhanced magnetic properties allowing higher powers to be achieved without significant increases in mass and dimension, together with the development of high voltage power electronic devices, it is now possible to extend the application of electomechanical actuation even to primary flying control surfaces. This paper highlights some design aspects in the development of electromechanical actuators (EMA's), draws attention to the several advantages of EMA's and their rare earth drive motors and addresses some of the problems that need to be tackled in order to achieve full certification for future aircraft.

This paper aims to describe how a novel biomimetic chewing robot was designed, including its motion, force, control and mechanical designs, and shows some initial experiments about motion tracking.

According to the biomechanics, the authors modeled the muscles of mastication in six linkages and the temporomandibular joint in higher kinematic pairs of point contact. As a result, the chewing robot was represented in a redundantly actuated parallel mechanism. With reference to literature data on the biological system, the authors specified the motion and force requirements for the robot via inverse kinematics and force analysis. A prototype of the robot was built, which has a position control system and is driven by six linear actuators. Experiments were conducted to show the capability of the robot in reproducing the human chewing motion.

A chewing robot was successfully modeled and developed, which is able to simulate the motion of human mastication in a biologically faithful way.

The chewing robot as a scientific instrument can be used to test dental materials and evaluate food textural properties of chewing.

Two higher kinematic pairs of point contact are proposed to simulate the two temporomandibular joints. The mechanism of the novel chewing robot is the first of this kind, which has two higher kinematic pairs of point contact and is a redundantly actuated spatial parallel mechanism.

The purpose of the paper is to present an approach to detect and isolate the aircraft sensor and control surface/actuator failures affecting the mean of the Kalman filter innovation sequence.

The extended Kalman filter (EKF) is developed for nonlinear flight dynamic estimation of an F‐16 fighter and the effects of the sensor and control surface/actuator failures in the innovation sequence of the designed EKF are investigated. A robust Kalman filter (RKF) is very useful to isolate the control surface/actuator failures and sensor failures. The technique for control surface detection and identification is applied to an unstable multi‐input multi‐output model of a nonlinear AFTI/F‐16 fighter. The fighter is stabilized by means of a linear quadratic optimal controller. The control gain brings all the eigenvalues that are outside the unit circle, inside the unit circle. It also keeps the mechanical limits on the deflections of control surfaces. The fighter has nine state variables and six control inputs.

In the simulations, the longitudinal and lateral dynamics of an F‐16 aircraft dynamic model are considered, and the sensor and control surface/actuator failures are detected and isolated.

A real‐time detection of sensor and control surface/actuator failures affecting the mean of the innovation process applied to the linearized F‐16 fighter flight dynamic is examined and an effective approach to isolate the sensor and control surface/actuator failures is proposed. The nonlinear F‐16 model is linearized. Failures affecting the covariance of the innovation sequence is not considered in the paper.

An approach has been proposed to detect and isolate the aircraft sensor and control surface/actuator failures occurred in the aircraft control system. An extended Kalman filter has been developed for the nonlinear flight dynamic estimation of an F‐16 fighter. Failures in the sensors and control surfaces/actuators affect the characteristics of the innovation sequence of the EKF. The failures that affect the mean of the innovation sequence have been considered. When the EKF is used, the decision statistics changes regardless the fault is in the sensors or in the control surfaces/actuators, while a RKF is used, it is easy to distinguish the sensor and control surface/actuator faults.

Looks at recent developments in methods of decentralising an aircraft’s hydraulic system made possible by the production of miniaturised electro‐hydraulic pumps with their own “smart” actuators.