Stephen D. Prior

An electric wheelchair mounted robotic arm - a survey of potential users

This paper describes the results of a survey which investigated and evaluated the needs and abilities of electric wheelchair users. The results of this survey will be used to develop a low-cost electric wheelchair-mounted robotic arm for use by physically disabled people to facilitate rehabilitation. The survey was undertaken by the author together with staff and students from occupational therapist training colleges, using a four-page questionnaire containing over 110 questions. The questionnaire was developed by the author together with Dr Robin Platts (Director of Orthotics), Mr Ian Bayley (Director of the London Spinal Unit) and senior occupational therapists at the Royal National Orthopaedic Hospital, Stanmore, Middlesex. After a successful trial the questionnaire was used with 50 severely disabled people from various backgrounds and social circumstances. The results of this survey show that the average electric wheelchair user is 40 years old, single (68%), living at home (58%) with family support (69%) and without any paid employment (79%). The most prevalent disability is spinal cord injury (24%) followed by multiple sclerosis (16%). The survey has identified several tasks which electric wheelchair users find impossible to do, and some of these will form part of the design specification. Finally 84% of the survey subjects would consider buying such a robotic aid.

Using personality type differences to form engineering design teams

Abstract This paper argues for the greater use of personality type instruments such as the Myers-Briggs Type Indicator (MBTI) and the Keirsey Temperament Sorter II (KTS II), when forming engineering design teams. Considering the importance of teamwork in all aspects of education and industry, it is surprising that few universities in the UK use personality type information when forming design teams. This has led to many courses not getting the best out of their students, and more importantly the students not getting the most out of the teamworking experience. Various team formation methods are discussed and their relative strengths and weaknesses outlined. Normal personality type distributions in base populations are presented and compared with data from recent studies of engineering students, and the link between engineering, design and creativity is discussed. The results of this study have shown that the most important of the type preferences is the Sensing-iNtuitive (S-N) scale, with its proven link to creativity and learning styles. It is concluded that both engineers and designers have much in common, and a methodology of using personality type choice sets to select and form engineering design teams is proposed.

Measurements and simulation of a pneumatic muscle actuator for a rehabilitation robot

The performance of a pneumatic muscle actuator, invented by Jim Hennequin and used in a prototype wheelchair-mounted robot arm designed by the first author is reported. Experimental measurements were made of the output torque versus rotary motion and internal pressure. The torque available for a muscle of size 60 mm width by 90 mm length ranges from 1 to 15 Nm. The rotary stiffness of this muscle is 0.081 Nm/deg. A theory based on thermodynamic principles indicates that the efficiency of the pneumatic muscle actuator reaches a maximum of 67%. A simulation model of the dynamic behaviour of the muscle attached to the robot arm using one-dimensional flow theory was written in ACSL (Advanced Continuous Simulation Language). The resultant simulation gives good agreement to within ± 5% of the experimental values.

Development of a Novel Platform for Greater Situational Awareness in the Urban Military Terrain

The conflicts in Afghanistan and Iraq and the more recent war in the Gaza Strip have emphasized the need for novel platforms which provide for greater situational awareness in the urban terrain. Without intelligent systems, which can accurately provide real-time information, collateral damage to property will result, together with unnecessary civilian deaths. This situation is exacerbated by the fact that within the next decade 75% of the worlds population will be living in urban areas. This paper outlines the current state of unmanned aerial vehicles throughout the world and presents a novel design of a multiple rotary wing platform which has great potential for both military and civilian application areas.

Actuators for rehabilitation robots

This paper describes the use of pneumatic muscle actuators in rehabilitation robotics. The history and application of this type of actuator is reviewed, and the design of an electric wheelchair mounted rehabilitation robot, utilizing a new form of pneumatic muscle actuator, the flexator, is discussed. The theory of controllable compliance is detailed and experimental results based on the flexator actuator are given to support this theory.

Wheelchair-mounted robots for the home environment

Statistics on people with disabilities, together with data on the number and use of wheelchairs in the United Kingdom, are summarized. The history of electric-wheelchair-mounted robotic devices is detailed and critically reviewed. A novel design for a hybrid electropneumatic wheelchair-mounted robot for the home environment is presented.

The Middlesex University rehabilitation robot

This paper describes the development of an electrically powered wheelchair-mounted manipulator for use by severely disabled persons. A detailed review is given explaining the specification. It describes the construction of the device and its control architecture. The prototype robot used several gesture recognition and other input systems. The system has been tested on disabled and non-disabled users. They observed that it was easy to use but about 50% slower than comparable systems before design modifications were incorporated. The robot has a payload of greater than 1 kg with a maximum reach of 0.7 – 0.9 m.

Design and implementation of a mini quadrotor control system in GPS denied environments

This paper presents the design of quadrotor control architecture, based on crowd-sourcing electronics. The aim of this quadrotor is to provide a test-bed for vision-based autonomous navigation system in GPS denied environments. The control architecture consists of a cascaded structure, where an attitude controller nested in velocity and altitude controllers. The sub-controllers are all linear controllers with feedforward term to linearize the quadrotor dynamics. The control and sensor fusion algorithm is developed under Arduino compatible open source electronics, whereas the complete design also includes an additional downward facing optical flow sensor (PX4FLOW camera) for horizontal velocity estimation and vehicle altitude estimation, and a separate Linux embedded computer (Odriod-U3) for future Simultaneous Localization And Mapping (SLAM) vision algorithm development. In current stage, by utilizing the PX4FLOW sensor, it is capable of horizontal velocity control and altitude hold. Besides, a ground station GUI software is developed in MATLAB® for two-way telemetry visualization and in-air parameter tuning.

Gesture recognition for control of rehabilitation robots

This paper describes the development of a control user interface for a wheelchair-mounted manipulator for use by severely disabled persons. It explains the construction of the interface using tasks to define the user interface architecture. The prototype robot used several gesture recognition systems to achieve a level of usability better than other robots used for rehabilitation at the time. The use of neural networks and other procedures is evaluated. It outlines the experiments used to evaluate the user responses and draws conclusions about the effectiveness of the whole system. It demonstrates the possibility of control using a head mouse.

HALO the Winning Entry to the DARPA UAVForge Challenge 2012

The DARPA UAVForge challenge was designed to bring together a diverse group of UAV enthusiasts to develop the next generation, low cost, small unmanned air system (SUAS) for perch and stare operations in a military context. The challenge combined a web-based collaboration site with a live competitive fly-off event held at Fort Stewart, Georgia, USA in May 2012. UAVForge was a Defense Advanced Research Projects Agency (DARPA) and Space and Naval Warfare Systems Center, Atlantic (SSC Atlantic) initiative to leverage the exchange of ideas among an international community united. More than 140 teams and 3,500 registered citizen scientists from 153 countries participated in this year long event. From several selection rounds, a core of nine teams competed in the fly-off event and in June 2012 Team HALO from the UK was declared the winner scoring 47.7 points out of a maximum possible 60 points, with their co-axial tri-rotor Y6 design.