The impact of force equalization in minimizing the effect of drift in feedback transducers in torque-summed electromechanical actuators

This paper focusses on implementing force equalisation to reduce or eliminate torque disparities in a four-lane torque-summed electromechanical actuator that drives the inner board aileron control surface on the Sea Harrier aircraft. Proportional, integral, and derivative control action achieved position control of the common output shaft, following two failures. The analysis included the effect of inherent motor disparities and drift in feedback transducers. Three-phase motor models were considered to account for the influence of the inherent torque ripple effect, and the influence of inertial and aerodynamic loads over various flight envelopes were also included in the analysis. Simulation tests demonstrated that although torque disparities between mismatched lanes are influenced by drift in potentiometer readings, force equalization was proven to be effective in eliminating such deviations

Progress in Redundant Electromechanical Actuators for Aerospace Applications

The power to move aircraft control surfaces has advanced from being manually generated (by the pilot and transmitted via rods and links) to electrically transmitted (via wires) to operate control surface actuators. Various hydraulic, electromagnetic, and electromechanical architectures have been developed to provide the necessary power and to maintain the expected redundancy. Numerous aircraft actuator system designs have been proposed in the past decades, but a comprehensive review has yet to be undertaken. This review paper aims to fill this gap by providing a critical review of the actuation system designs developed for a variety of aircraft. The review focuses on aircraft actuator system designs, namely: electrohydraulic actuator systems, electromechanical actuator systems, and the force-fighting effect in redundant actuation systems. The significance and operational principle of each actuator system are critically analysed and discussed in the review. The paper also evaluates the solution proposed to address force-fight equalization (or force-fight cancelation) in force or torqued-summed architectures. Future trends in redundant actuation system development with reduced force-fighting effect in aircraft actuator systems are also addressed

Mathematical & Physical Modelling of a Quadrotor UAV

Unmanned aerial vehicles (UAVs) are now becoming a major topic of interest due to their flying capabilities attracting researchers who are working within various application. Quadrotors in particular are one of main types of UAVs that are now currently studied, where some of the main focuses are positional and attitude tracking. Currently, verifying these systems in simulation is generally processed through MATLAB/Simulink where the dynamics are thoroughly analyzed. In this paper, the results attained from the mathematical dynamics implemented in Simulink will be justified using ADAMS environment. This software was purposely developed to accurately model the dynamics of mechanical systems in 3D without considering any equations of motion. SolidWorks is used to design the quadrotor frame that satisfies the properties of the proposed system in Simulink. Setting the control inputs as angular velocity of each motor will generate a relative thrust in order for the vehicle to achieve motion. Finally, the dynamic behavior on ADAMS and Simulink are compared as the control inputs are identically applied, which has revealed a marginal difference between the resultant motions

BCU Magnesium Symposium 2017 Abstract Booklet

Abstracts of magnesium research at BCU and Meridian Technologies Ltd, supplementary material to the BCU Magnesium symposium 20 July 201

Design and Development of Multi-Lane Smart Electromechanical Actuators

The unavoidable element in the development of flight control systems (to date) has been in hydraulic actuators. This has been the case primarily because of their proven reliability and the lack of alternative technologies. However, the technology to build electromechanically actuated primary flight control systems is now available, which may mark the end of the hydraulic actuation systems - an important step for the development of the future 'all-electric' aircraft. Design and Development of Multi-Lane Smart Electromechanical Actuators describes design concepts in electromechanical actuators by considering an actuator that has the capability to drive the aerodynamic and inertial loads of an aileron control surface similar to that of the Sea Harrier. It provides the necessary theoretical background to design smart multi-lane electromechanical actuation systems, and provides a general methodology that engineers (electrical, mechanical, mechatronic, aerospace or chemical) will find useful

Force Equalisation in Torque-Summed Electromechanical Actuators

This paper examines the effects of force equalisation in a four lanes torque-summed architecture that was designed to drive a control surface similar to that on the Sea Harrier, following two motor failures. PID control was implemented to control the common output shaft. Force equalization was assessed in the presence of inherent internal motors parameters deviations as well as inherent drift in feedback transducers. 3-phase motor models were utilised to cater for the torque ripple effects. Force equalization was proven to be most effective on deviations due to drift in potentiometer readings

UAV Testbed Training Platform development using Panda3d

Purpose – The paper aims to report the development of an Unmanned Aerial Vehicle (UAV) Testbed Training Platform (TTP). The development is to enable users to safely fly and control the UAV in real time within a limited (yet unconstrained) virtually created environment. Thus, the paper introduces a hardware–virtual environment coupling concept, the Panda3D gaming engine utilization to develop the graphical user interface (GUI) and the 3D-flying environment, as well as the interfacing electronics that enables tracking, monitoring and mapping of real-time movement onto the virtual domain and vice verse. Design/methodology/approach – The platform comprises a spring-shuttle assembly fixed to a heavy aluminium base. The spring supports a rotating platform (RP), which is intended to support UAVs. The RP yaw, pitch and roll are measured by an inertial measurement unit, its climb/descend is measured by a low cost infrared proximity sensor and its rotation is measured by a rotary optical encoder. The hardware is coupled to a virtual environment (VE), which was developed using the Panda3D gaming engine. The VE includes a GUI to generate, edit, load and save real-life environments. Hardware manoeuvres are reflected into the VE. Findings – The prototype was proven effective in dynamically mapping and tracking the rotating platform movements in the virtual environment. This should not be confused with the hardware in loop approach, which requires the inclusion of a mathematical model of the hardware in a loop. The finding will provide future means of testing navigation and tracking algorithms. Research limitations/implications – The work is still new, and there is great room for improvement in many aspects. Here, this paper reports the concept and its technical implementation only. Practical implications – In the literature, various testbeds were reported, and it is felt that there is still room to come up with a better design that enables UAV flying in safer and unlimited environments. This has many practical implications, particularly in testing control and navigation algorithms in hazardous fields. Social implications – The main social impact is to utilise the concept to develop systems that are capable of autonomous rescue mission navigation in disaster zones. Originality/value – The authors are aware that various researchers have developed various testbeds, at different degrees of freedom. Similarly, the authors are also aware that researchers have used game engines to simulate mobile robots or sophisticated equipment (like the VICON Motion Capture System) to measure to perform complex manoeuvres. However, the cost of this kind of equipment is very high, autonomous movements are planned in restricted environments and tested systems are only autonomous in certain setups. However, the idea of mapping the dynamics of an avatar flying object onto a 3D-VE is novel. To improve productivity and rapid prototyping, this paper proposes the use of commercially available game engines, such as the Panda3D, to create virtual environments

Using unity for 3D object orientation in a virtual environment

Although Unmanned Aerial Vehicles (UAVs) have gained a lot of attention by researchers in the past couple of decades, the development of UAV safe and efficient test platforms still needs much attention. The main reason for this being the unstable nature of the platforms and the potential risks associated with multi-rotor UAVs. To address and understand the above problems, this paper introduces UAV navigation in a virtually generated environment that is coupled to the real hardware platform. The virtual environment (VE) is developed using the Unity game engine, providing users with sufficient tools to build 3 dimensional, multi-level maps. The VE parses the orientation data (received from the hardware) and depicts instances of a UAV inside the created VE maps. Thus, this approach provides a suitable environment to examine different geographical scenarios and to test control and navigation algorithms to their limits without the need to physically manoeuvre the UAV and risk damaging it while doing so

Dynamic Modelling and Analysis of a Quadrotor Based on Selected Physical Parameters

Over the past decade, control techniques have been widely implemented on quadrotors to achieve the desired positions within the coordinate system. However, ensuring that the dynamics are correct and that similar results to a physical model can be obtained has been a question of interest. In this paper, the quadrotor dynamics are thoroughly analysed in simulation without using any controllers. Specifically, suitable actuators and propellers have been selected to generate ideal thrusts that will enforce the unmanned aerial vehicle (UAV) to lift. By using kinematics approach, one can analyse the expected motion of the UAV after a certain thrust is applied on all motors. Hence, the dynamics of the proposed quadrotor are recognised and verified through numerical simulations, leading to presenting the motions of the physical model. The results attained have illustrated promising results in which a comparative study between experimental and theoretical methods have presented little to no errors