Active tiltrotor whirl flutter control

Supervisors: Dr Jonathan du Bois, Dr David Cleaver

Future rotorcraft need to combine the advantages of vertical take-off and landing with better range and endurance as well as improved efficiencies, pilot and crew comfort, and payload capacity. Tiltrotors are important to address such challenges as they convert from helicopter mode to aeroplane mode by changing the inclination of their proprotors from vertical to horizontal.

This configuration poses new challenges; in particular, dynamic instabilities arising from the location of the proprotors at the end of flexible wings. Presently this is overcome by increasing the stiffness and consequently the weight of the structural elements. Active control systems need to be developed to prevent whirl flutter and allow more lightweight, efficient structures to be employed.

Novel integrated control of fluid-borne noise in fluid power systems

Supervisor: Dr Min Pan

Hydraulically-powered machines generate high noise levels; a problem that industry and the general public are becoming increasingly aware of. Applying existing passive and active systems for fluid-borne noise attenuation in fluid power systems has shown to be effective in reducing noise. However, they are limited by their heavy weight, bulky size and cancellation bandwidth.

This project will investigate a novel noise control system that integrates an active attenuator and passive tuned flexible hoses to obtain effective, robust and high bandwidth noise attenuation for fluid power systems.

Flexure coupling mechanisms for high performance robotics and automation

Supervisors: Dr Nicola Bailey, Professor Patrick Keogh

Many automated processes depend upon fast, repeatable and precisely controlled motion of multibody mechanisms. Conventional multibody systems, used in robotics and automated machinery, contain joints that give complex and uncertain tribological effects, impacting negatively on performance. Eliminating the interaction forces within the joint by replacing the bearings with flexure couplings, which are compact deformable structures acting as pseudo-joints, provides more precise and predictable small-scale motion behaviour. Research is needed to optimise flexure couplings to give precise three dimensional motion.

Perception and autonomy for unmanned aircraft

Supervisors: Dr Jonathan du Bois, Dr Pejman Iravani, Dr David Cleaver

Autonomous aircraft are becoming prevalent. Their integration into civilian airspace is presently limited by safety concerns over their sensing and decision-making processes. This research covers a variety of technologies including - sensors and data fusion - detect and avoid - route planning - system health monitoring and prognostics - mission optimisation

This work aims to create robust and reliable automation to enable the uptake of unmanned aircraft systems across a range of civilian sectors.

Additive manufacturing for next-generation hydraulic components

Supervisors: Dr Min Pan, Professor Andrew Plummer

An advantage of additive manufacturing is the ability to form complex geometries that are impossible to make by conventional methods. The fabrication of novel geometries enables greater product optimisation for a particular function. There are also benefits in terms of the environmental impact of component manufacture and a reduction of lead-time for component production or redesign. This project will investigate novel approaches for the design of lightweight, high performance hydraulic components for aerospace and other applications.

Safety systems for healthcare technologies

Supervisor: Dr Ioannis Georgilas

The number of autonomous systems in healthcare applications is increasing. Spanning from robotic surgery and exoskeletons, to intelligent medicine delivery, novel solutions are being proposed to tackle complex medical issues. The close proximity to vulnerable users means that these systems need to be extremely safe to operate. Within this context traditional safety paradigms lack the ability to ensure safety for modern systems. This project will look into the safety aspects of healthcare technologies proposing a new approach to system development and evaluation.

Hydraulic accumulator using a phase-change fluid

Supervisor: Dr Nigel Johnston

Hydraulic accumulators can be used as energy storage devices in hybrid vehicles and other machines, and provide a simple means of saving energy. However at present their energy density is low compared with batteries and other storage devices. The proposed project will be an investigation of accumulators containing fluid that changes phase between gas and liquid when the accumulator is charged and discharged. This has the potential to increase the energy density considerably.

Methods for accurate generation of very large forces (fully-funded studentship from NPL)

Supervisor: Professor Andrew Plummer

This project will support the design of a machine capable of generating a force of 10MN with a repeatability better than 1kN. World-leading accuracy is required by the National Physical Laboratory, which is the UK's National Measurement Institute, for calibration of force sensors with traceability to the SI unit definitions.

Robotics

Supervisor: Dr Pejman Iravani

Various opportunities are available in the area of robotics, including:

• developing soft polymer robots including touch-sensitive skin materials for robots
• computer vision and control of autonomous quad bike
• intelligent power prosthetics and orthotics/exoskeletons

Modelling unsteady turbulent flow in pipes with high accuracy, bandwidth and efficiency

Supervisor: Dr Nigel Johnston

Unsteady flow is a key feature of many engineering systems. There is a need for reliable, accurate and efficient mathematical models and simulation tools. Efficient and accurate methods are available for modelling unsteady laminar flow. However, there is currently a lack of models for turbulent flow transients; existing models omit some key features, leading to uncertainty and inaccuracy. This project seeks to address these issues by creating transient turbulent flow models which are efficient, accurate, robust, reliable and properly validated.

Digital Hydraulic System Controls

Supervisors: Dr Min Pan, Professor Andrew Plummer

In most hydraulically powered systems, the speed and/or force of a load are controlled using valves to throttle the flow and thus reduce the hydraulic pressure. This is a simple but extremely inefficient method as the excess energy is lost as heat, and it is common for more than 50% of the input power to be wasted in this way. Digital hydraulics, which means hydraulic systems having discrete valued components actively controlling system output, can potentially have higher efficiency and less energy loss. This project will investigate digital hydraulics via analytical modelling and experimental validation.

Distributed actuation and control for active structures

Supervisor: Professor Andrew Plummer

The next generation of actuation systems, whether for aircraft control, robotic manipulation or other multi-axis applications, will be distributed through and closely integrated with the load-bearing structure. These smart morphing structures will provide better static and dynamic performance, redundancy and more versatility than current designs. This PhD research project will investigate concepts and control for fluid actuation of pinned prestressed frames or tensegrity structures.