Xiaofeng Wu

Xiaofeng Wu
The University of Sydney · School of Aerospace, Mechanical and Mechatronic Engineering

Doctor of Philosophy

About

111
Publications
16,432
Reads
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918
Citations
Citations since 2016
62 Research Items
631 Citations
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2016201720182019202020212022020406080100120140
2016201720182019202020212022020406080100120140

Publications

Publications (111)
Article
Full-text available
The literature since Apollo contains exhaustive material on attitude filtering, usually treating the problem of two sensors, a combination of state measuring and inertial devices. More recently, it has become popular for a sole attitude determination device to be considered. This is especially the case for a star tracker given its unbiased stellar...
Article
Recently, mega Low Earth Orbit (LEO) Satellite Network (LSN) systems have gained more and more attention due to low latency, broadband communications and global coverage for ground users. One of the primary challenges for LSN systems with inter-satellite links is the routing strategy calculation and maintenance, due to LSN constellation scale and d...
Article
The perforation of concrete‐like material targets against impact by nondeforming projectiles is always the research focus in engineering protective domain. In the present paper, a new punching plug model is proposed based on the similar features with punching shear in concrete slabs, utilizing the failure criterion of modified Mohr‐Coulomb. Semi‐em...
Article
Full-text available
This paper presents the design of a flexible bending actuator using shape memory alloy (SMA) and its integration in attitude control for solar sailing. The SMA actuator has advantages in its power-to-weight ratio and light weight. The bending mechanism and models of the actuator were designed and developed. A neural network based adaptive controlle...
Article
On-orbit manufacturing can reduce the cost and time needed by space exploration missions because in-situ maintenance activities can be achieved without the need for additional launches. Furthermore, recent developments in materials science in terms of better mechanical and thermal performance have allowed this application to become a potential real...
Article
Full-text available
Cold spray is emerging as an additive manufacturing technique, particularly advantageous when high production rate and large build sizes are in demand. To further accelerate technology’s industrial maturity, the problem of geometric control must be improved, and a neural network model has emerged to predict additively manufactured geometry. However...
Data
This is the supplementary materials for the article entitled "Data-Efficient Neural Network for Track Profile Modelling in Cold Spray Additive Manufacturing" (DOI: 10.3390/app11041654).
Presentation
Star trackers offer one of the most accurate means of attitude determination available to medium and large satellites. The technology has distinct advantages over alternative attitude determination sensors which, among other disadvantages, may be subject to drift, fluctuations due to space weather events and interference from on-board components. H...
Article
Full-text available
Currently, it appears that there is a lack of understanding related to the role of SSF, in the two-phase behavior of the deceleration history, which is an issue discussed recently in the impact dynamics field. This paper analytically and numerically focuses on the effect of SSF on the projectile deceleration characteristic of concrete-like targets....
Article
Full-text available
Most traffic surveillance systems are based on videos which captured by fixed cameras on bridges, intersections, etc. However, many traffic collisions may occur in many places without such surveillance systems, e.g., in rural highway. Researchers have developed a set of techniques to improve safety on these places, while it is still not enough to r...
Conference Paper
This paper presents a method for accuracy validation of a star tracker optical system using night sky testing. Data from the IAU2000A earth rotation model was used to correct for Earth precession and nutation effects. This method was tested by analysing data captured using a stationary smartphone camera over a period of 75 minutes. Applying these c...
Presentation
Full-text available
Cold spray additive manufacturing is an emerging technology that offers unique advantages, including high production rate, unlimited product size and the ability to process oxygen-sensitive materials. However, dimensional control and accuracy in cold spray additive manufacturing are challenging, which limits its integration into commercial manufact...
Article
Full-text available
This paper presents a new adaptive small chattering sliding mode control (SCSMC) scheme that uses reinforcement learning (RL) and time-delay estimation (TDE) for the motion control of free-floating space robotic manipulators (FSRM) subject to model uncertainty and external disturbance. The proposed sliding mode control scheme can achieve small chat...
Article
The free-flying space manipulators present challenges in controlling the motions of both the spacecraft bus and the manipulator, because of the highly-coupling system dynamics and the unknown space environment disturbances. Although the sliding mode controllers are robust to the unknown disturbances and system uncertainties, the chattering effect c...
Article
Full-text available
The 2-unit CubeSat INSPIRE-2/AU03 was designed, built, tested, delivered, and accepted by the European Union’s QB50 project in less than 10 months and for less than US$120,000 in non-salary outlays including launch, despite being a first satellite. It carried 5 instruments (a multi-Needle Langmuir Probe, a diffraction-limited spectrograph, an advan...
Poster
Full-text available
Full journal version (Open Access) is available: doi.org/10.3390/ma12172827; https://doi.org/10.3390/app11041654
Article
Previously, the combined thermoelectric generator and cooler (TEG-TEC) control technique was proposed for thermal management of devices, where the TEG mode is used for energy harvesting and the TEC mode is used for active temperature control. This research significantly improves the TEG-TEC control technique by including the components that ensure...
Article
Many studies indicate that projectile deceleration exhibits a quasi-constant behavior in the tunneling penetration stage of the rigid penetration mode for both metal-like and concrete-like materials. As to the issue, in the present paper the penetration process under the rigid penetration mode was revised, where a two-phase penetration theory is pr...
Article
Full-text available
This paper presents a space mission planning tool, which was developed for LEO (Low Earth Orbit) observation satellites. The tool is focused on a two-phase planning strategy with clustering preprocessing and mission planning, where an improved clustering algorithm is applied, and a hybrid algorithm that combines the genetic algorithm with the simul...
Article
Full-text available
Cold spray additive manufacturing is an emerging technology that offers the ability to deposit oxygen-sensitive materials and to manufacture large components in the solid state. For further development of the technology, the geometric control of cold sprayed components is fundamental but not yet fully matured. This study presents a neural network p...
Data
This is the supplementary materials to "Neural Network Modelling of Track Profile in Cold Spray Additive Manufacturing" (DOI: 10.3390/ma12172827).
Conference Paper
A stellar gyroscope system is proposed, designed, and its accuracy evaluated. The stellar gyroscope operates by imaging over long exposure times and measuring the position and size of smeared stars to determine a spin axis and slew rate. The benefits of using a stellar gyroscope include a lack of sensor bias and a lack of need for a separate gyrosc...
Conference Paper
This paper presents a new calibration methodology for in-orbit estimation of optical parameters for star trackers. The novel approach is specific for a wide field of view star tracker. The work is based from the CROSS project of the University of Sydney, which involves development of a multi-sensor, wide field of view star tracker designed for smal...
Article
Although the integration of heat pumps with fuel cells for micro combined heat and power is a viable solution for reducing hydrogen energy consumption, recent studies have typically only considered the vapour compression cycle as the selected heat pump. This research proposes a multi-objective optimisation methodology to analyse the performance of...
Article
Full-text available
In this paper, a bi-level Delta-Sigma modulator-based MEMS gyroscope design is presented based on a Model Predictive Control (MPC) approach. The MPC is popular because of its capability of handling hard constraints. In this work, we propose to combine the 1-bit nature of the bi-level Delta-Sigma modulator output with the MPC to develop a 1-bit proc...
Article
Although FC based electric buses are currently popular on urban streets or in short transit routes within large facilities, the version that is designed to operate on a highway, which has much higher dynamic requirements, is yet to be well developed. This research proposes to adopt the NSGA-II based multi-objective optimization scheme to optimize a...
Article
This paper develops a drone control prototype based on web technology with the aid of hand gesture. The uplink control command and downlink data (e.g., video) are transmitted by WiFi communication, and all the information exchange is realized on web. The control command is translated from various predetermined hand gestures. Specifically, the hardw...
Article
Full-text available
An existing propulsion system is modified to obtain variable ISP capabilities that could be used to modulate thrust. This created an engine that is able to use low thrust and high ISP setting for interplanetary travel and use high thrust and low ISP setting for attitude control and compensating for atmospheric drag. A cold gas thruster (CGT) was cr...
Article
Quantum Key Distribution utilises fundamental quantum properties and mechanics to generate a cryptographic key, ensuring the highest security regardless of advances to computer processing. AMMEQ-1 is a 3U cubesat being developed by The University of Sydney, Australia hosting a primary payload provided by Centre for Quantum Technologies, Singapore....
Article
The School of Aerospace, Mechanical and Mechatronics Engineering (AMME) at The University of Sydney is proposing the design of a commercially viable 100 kg class microsatellite, HISA - a Hyperspectral Imaging Satellite for Australia. The primary mission is centred around the application of hyperspectral imagery to address compelling agricultural an...
Conference Paper
Full-text available
The ratio of thermoluminescence glow curve area of LiF and BeO dosimeters is found to be directly proportional to average LET (linear energy transfer) of impinging radiations. Using this phenomenon and widely available TLD-700 (7 LiF: Mg, Ti) and BeO (Thermolux) dosemeter chips the authors have developed a TLD-Microdosimeter (LiBe-14) emulating a g...
Presentation
Full-text available
Proposed application of a TLD-based personal microdosimeter (LiBe-14) for dosimetry and risk assessment of astronauts enduring long term habitat in LEO space stations like ISS. The LiBe-14 is a miniature surrogate of a real life gas-filled Tissue Equivalent Proportional Counter (TEPC).
Article
As an increasing number of mobile robotic systems with an ever greater autonomous capability are developed, there is a proportional increase in the demand for fast and accurate state estimation for those systems. For these increasingly complex systems, high performance and light, compact form factors are often opposing forces in design. In addition...
Article
Full-text available
The thermoelectric generator (TEG) is a clean and noiseless renewable electrical power source that requires no moving parts. Unfortunately, the practicality of TEGs is currently limited by its typical low conversion efficiencies. Subsequently, researchers have taken many approaches to improve the efficiency of the TEG. One of such approaches is the...
Article
A vast wealth of literature exists on the topic of rocket trajectory optimisation, particularly in the area of interplanetary trajectories due to its relevance today. Studies on optimising interstellar and intergalactic trajectories are usually performed in flat spacetime using an analytical approach, with very little focus on optimising interstell...
Article
Full-text available
Maximum power point tracking (MPPT) techniques are popularly used for maximizing the output of solar panels by continuously tracking the maximum power point (MPP) of their P-V curves, which depend both on the panel temperature and the input insolation. Various MPPT algorithms have been studied in literature, including perturb and observe (P&O), hil...
Article
This paper reports the near space ballooning experiment carried out at Australian outback town West Wyalong (33°51′S, 147°24′E) on 19 July 2015. Several dedicated electronic detectors including digital temperature and acceleration (vibration) sensors and an energy compensated PIN-diode gamma ray dosimeter were installed in a thermally insulated Sty...
Article
Despite being a major component in the teaching of special relativity, the twin `paradox' is generally not examined in courses on general relativity. Due to the complexity of analytical solutions to the problem, the paradox is often neglected entirely, and students are left with an incomplete understanding of the relativistic behaviour of time. Thi...
Article
Full-text available
Demand for fast and accurate state estimation in embedded systems has been increasing lately, at least in part due to mobile robotics such as UAVs. The desire to maintain high performance but with compact form factors leads to implementation issues especially with more complex systems. A hardware based approach using Field Programmable Gate Arrays...
Article
This paper introduces the design of an innovative attitude control subsystem by using linear piezoelectric actuators and a Commercial off-the-shelf DC brushless motor. CubeSat is now becoming a popular miniaturized satellite standard for space researches and technology demonstrations. However, precise attitude control systems are challenging on Cub...
Conference Paper
Full-text available
Nanosatellites, while lowering the cost and ease of space access, suffer the issue of reduced performance compared to larger satellites, particularly when it comes to attitude determination and control. Field Programmable Gate Arrays (FPGAs) have been used in the past to make up for the shortfall in capability but tend to have more complicated deve...
Article
The model predictive control (MPC) has great advantages in dealing with complex control constraints. However, traditional MPCs are too complex to implement in real-time embedded systems. This is especially true for nano-satellites due to limited on-board resources. This paper introduces a novel 1-bit processing based MPC (OBMPC) algorithm for a fra...
Conference Paper
This paper presents an Ultrasonic Motor (USM) driver design for CubeSat reaction wheel, where it takes the limitation of size, mass and power source into consideration. It demonstrates whether CubeSat reaction wheel design is feasible to use Ultrasonic Motor. In this paper a novel ultrasonic motor driver circuit is designed base on LC resonance. Th...
Article
Full-text available
I-INSPIRE II is designed for the European QB50 project, which is funded by FP7 and leaded by the von Karman Institute for Fluid Dynamics (VKI). QB50 has the scientific objective to study in situ the temporal and spatial variations of a number of key constituents and parameters in the lower thermosphere (90-320 km), a region which is very under-samp...
Conference Paper
The i-INSPIRE satellite is the result of a collaborative project at the University of Sydney, across the science and engineering faculties. The satellite is a compact tube-shaped pico-satellite with a mass of less than 0.75 kg. i-INSPIRE carries three science instruments - a photonic spectrograph, a radiation counter and an imaging camera, and will...
Conference Paper
For virtual satellites, the main challenge for the attitude determination and control module is to maintain the performance with weak wireless inter-satellite links (ISL). Such weak ISL leads to large data loss, high bit error rate, and long transmission delay during the real-time control process, which beyond the competence of traditional linear c...
Conference Paper
Optical wedge is one kind of prism with small vertex angle and its characteristic of refraction can be used to deflect optical path. In this way, optical wedge can provide the light sources in different angular position. If rotating two optical wedges with certain angular velocity, the imaging point will be adjusted contiguously. Based on this, we...
Conference Paper
Full-text available
Satellites are becoming an increasingly invaluable tool to aid academic research in a variety of applications. The traditional high cost barrier of space access has led to the development of low cost nano-satellites which emphasise the use of commercial-off-the-shelf (COTS) components and other standardised components. This leads to somewhat lacklu...
Conference Paper
In a virtual satellite, communications between any two spacecraft modules may be established on weak wireless inter-satellite using limited resources. The challenges for the attitude determination and control module include maintaining the performance with large data loss and time delay, limited on-board computational resources and hard constraints...