Efficient charging pad for unmanned aerial vehicle based on direct contact

Recently there has been significant interest in the development of autonomously Unmanned Aerial Vehicles (UAVs), especially the rotor-based robots, which are highly maneuverable and can vertically take-off and land. However, the discharge characteristics and charge storage capacity limitations of their lithium-ion battery can restrict their flight time endurance. The utilization of an automatic drone charging station is therefore desirable for these robots. This paper proposes a fully automatic contact-based charging station for UAVs to recharge UAV's and thereby solve the UAV's flight endurance limitations. The ground station comprises square-shaped copper plates of consecutively polarized positively and negatively in the form of a chess board with specific dimensions to ensure electrical contact when landing. The design methodology employed with the charging station accounts for the variations of the orientation of the UAV after landing on the platform. Furthermore, this innovation employs an autonomous recharging process after touchdown. Subsequently, this technology relaxes usual flight time constraints and improves overall mission times. The UAV equipped with a suitable hardware circuit the onboard circuit consists of six bridge diode rectifiers to modulate the polarity of the four UAV's contact terminals that allows autonomous recharge regardless of the yaw angle between UAVs and the charging pad platform, this, in turn, simplifies landing protocols. The result shows that the charging circuit successfully charged the UAV battery until 12.5v

Development of an in-sole plantar pressure measurement device

This paper describes the design and development of an In-sole Plantar Pressure Device (IPPD) to measure underfoot pressure. Knowledge on underfoot pressure is important for different purposes. It is essential for doctors and clinicians to have information about underfoot pressure to enable them to diagnose foot problems. Currently, underfoot pressure ranges have not been effectively established, and there is insufficient information about the minimum and maximum values of underfoot pressure. Likewise, constraints with regard to the implementation of insole systems still persist and are represented by the need to put a spacer on the sensor during measurements, and the problem of sensor parameters changing after the calibration. These challenges are addressed in this work and preliminary results or performance of the proposed device are then presented

Image processing based foot plantar pressure distribution analysis and modeling

Although many equipments and techniques are available for plantar pressure analysis to study foot pressure distributions, there is still a need for mathematical modelling references to compare the acquired measurements. In order to derive formulas in this concern, this research proposes a measurement-based method which adopts the reference measured parameters such as; the weight of a subject, contact-area size, age, and the pressure level distribution over a plantar image captured by the EMED plantar pressure system. The proposed analysis and algorithm were verified by a group 79 volunteers through data collection with four various measurement conditions. Three mathematical modelling equations have been proposed that describe the relationships between the foot plantar pressure levels and the subject’s body mass, foot size, and age. The modelling of foot plantar pressure could be useful for various applications such as gait analysis, hospitals, clinics, custom shoe making, and early detection of ulceration in the case of diabetic patients

Foot plantar pressure distribution modeling based on image processing

Several factors have been associated with the distribution of plantar foot pressure, including: (i) the body weight, (ii) age, (iii) foot structure and (iv) standing / walking strategy. It is predicted that the biomechanics of the foot is influenced by the structure of the foot. The objective of this study was to obtain the plantar pressure distribution model of the foot using custom image processing algorithms upon the images captured by a commercial plantar pressure measurement machine, the EMED-X. The study involved the participation and data collection from 79 human subjects, ranging from age 20–60 years old. This model can be analysed further to be used as a predictor for the formation of foot ulceration in certain subjects

An investigation of a catalyst free PECVD nanocrystalline graphene/graphite on insulator

The unique electrical and optical properties of graphene have attracted application as transparent electrodes, transistors and photodetectors. However, the small flake size of mechanical exfoliated graphene has limited its scalability to large area production. Recently, large area graphene is produced through chemical vapour deposition (CVD) and epitaxial growth method. CVD of graphene on insulator or metal-catalyst is considered low cost and process flexible. This is because graphene film quality and deposition rate can be controlled through process parameters such as temperature, gas flow rate and gas mixture. Large area CVD graphene on metal-catalyst such as Ni or Cu is amongst other established method but the need for processing steps, such as film transfer and metal etching can ultimately damage the graphene and affect device performance. Therefore, the research attention is now focused on catalyst free CVD graphene process on insulator materials such as silicon dioxide (SiO2).In this work, the nanocystalline graphene/graphite (NCG) films are synthesised in a mixture of methane (CH4) and hydrogen (H2) environment using radio frequency chemical vapour deposition (RF PECVD) without metal transition catalyst, deposited directly onto 150 mm diameter silicon wafer with an insulating substrate, such as SiO2, is presented. The as-deposited NCG films properties depend on deposition conditions such as growth temperature, growth time, pressure, mixtures or flow rates of precursor, RF power and substrate material. Initially, the growth temperatures are varied in the range of 600 °C to 850 °C, while keeping other deposition parameters unchanged, and subsequently the properties of the as-deposited NCG film is studied. The nanocrystalline nature of as-deposited film are analysed based on their Raman spectra, whereas the film thickness and sheet resistances are characterised using ellipsometry spectroscopy and a simple four point probe measurements respectively.The electrical properties of the NCG films are performed using I-V measurement on a simple two terminal device with titanium/nickel (Ni/Ti) contacts. Transmission line method (TLM) structures with Ni/Ti probe pads are also fabricated for contact and sheet resistances measurement purposes