• Active robot learning for building up high-order beliefs

      Li, Dayou; Liu, Beisheng; Maple, Carsten; Jiang, Daming; Yue, Yong (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2008)
      High-order beliefs of service robots regard the robots' thought about their users' intention and preference. The existing approaches to the development of such beliefs through machine learning rely on particular social cues or specifically defined award functions. Their applications can, therefore, be limited. This paper presents an active robot learning approach to facilitate the robots to develop the beliefs by actively collecting/discovering evidence they need. The emphasis is on active learning. Hence social cues and award functions are not necessary. Simulations show that the presented approach successfully enabled a robot to discover evidences it needs.
    • Alignment method with application to gas chromatography / mass spectrometry screening

      Hitchcock, Jonathan James; Li, Dayou; Maple, Carsten; Keech, Malcolm (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012-09-08)
      The paper presents a new spectrum-based alignment method that is able to precisely adjust the retention times of Gas Chromatography / Mass Spectrometry data so that corresponding scans of two samples can be chosen for comparison purposes. It includes the ability to do precise alignment within fractions of a scan; this is equivalent to doing sub-pixel registration of images.
    • Anti-reflection structures fabricated by direct laser interference technology under different ambiances

      Wang, Dapeng; Yue, Yong; Zhang, Ziang; Li, Dayou; Maple, Carsten; Wang, Zuobin; University of Bedfordshire (IEEE, 2013-08)
      In this paper, we take the strategy of direct laser interference technology to modify the silicon surface under air and sulphur hexafluoride (SF6) gas ambiance conditions. With the investigation of optical properties, the silicon spike structures (known as black silicon) which were fabricated in the SF6 ambiance showed the excellent ability of reducing light reflection with a broadband spectrum. For comparison, well-defined microcone structures were fabricated in the air ambiance. After hydrofluoric (HF) acid wiping off the oxides on the surface, micro cone structures have shown the anti-reflection function as well and its reflective behaviour was dependent on the structural depth relatively. Due to a high impurities concentration of spike structures obtained in the SF6 ambiance, applications of sulphur-doped black silicon would be limited. To obtain large-scale uniform structures, direct laser interference technology in the air ambiance could be an alternative.
    • Both antireflection and superhydrophobicity structures achieved by direct laser interference nanomanufacturing

      Wang, Dapeng; Wang, Zuobin; Zhang, Ziang; Yue, Yong; Li, Dayou; Qiu, Renxi; Maple, Carsten; University of Bedfordshire; Changchun University of Science and Technology; Xi'an Jiaotong-Liverpool University (American Institute of Physics (AIP), 2014)
      Inspired by nature, a number of techniques have been developed to fabricate the bionic structures of lotus leaves and moth eyes in order to realize the extraordinary functions of self-cleaning and antireflection. Compared with the existing technologies, we present a straightforward method to fabricate well-defined micro and nano artificial bio-structures in this work. The proposed method of direct laser interference nanomanufacturing (DLIN) takes a significant advantage of high efficiency as only a single technological procedure is needed without pretreatment, mask, and pattern transfer processes. Meanwhile, the corresponding structures show both antireflection and superhydrophobicity properties simultaneously. The developed four-beam nanosecond laser interference system configuring the TE-TE-TE-TE and TE-TE-TE-TM polarization modes was set up to generate periodic micro cone and hole structures with a huge number of nano features on the surface. The theoretical and experimental results have shown that the periodic microcone structure exhibits excellent properties with both a high contact angle (CA = 156.3°) and low omnidirectional reflectance (5.9–15.4%). Thus, DLIN is a novel and promising method suitable for mass production of self-cleaning and antireflection surface structures.
    • Case study: multi-role shadow robotic system for independent living

      Maple, Carsten; Yue, Yong; Li, Dayou; Bochenkov, Alexey; University of Bedfordshire (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012)
      The project is focused on development and prototyping of remotely-controlled, semi-autonomous robotic solutions in domestic environments to support elderly people. In particular, the SRS project is demonstrating an innovative, practical and efficient system called "SRS robot" for personalised home care and assisted living.
    • Coordinated iterative learning control schemes for train trajectory tracking with overspeed protection

      Sun, Heqing; Hou, Zhongsheng; Li, Dayou (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012)
      This work embodies the overspeed protection and safe headway control into an iterative learning control (ILC) based train trajectory tracking algorithm to satisfy the high safety requirement of high-speed railways. First, a D-type ILC scheme with overspeed protection is proposed. Then, a corresponding coordinated ILC scheme with multiple trains is studied to keep the safe headway. Finally, the control scheme under traction/braking force constraint is also considered for this proposed ILC-based train trajectory tracking strategy. Rigorous theoretical analysis has shown that the proposed control schemes can guarantee the asymptotic convergence of train speed and position to its desired profiles without requirement of the physical model aside from some mild assumptions on the system. Effectiveness is further evaluated through simulations.
    • The development of a semi-autonomous framework for personal assistant robots - SRS Project

      Qiu, Renxi; Ji, Ze; Chivarov, N.; Arbeiter, Georg; Weisshardt, Florian; Rooker, M.; Lopez, R.; Kronreif, G.; Spanel, M.; Li, Dayou; et al. (IGI Global, 2013)
      SRS is a European research project for building robust personal assistant robots using ROS (Robotic Operating System) and Care-O-bot (COB) 3 as the demonstration platform. A semi-autonomous framework has been developed in the project. It consists of an autonomous control structure and user interfaces that support the semi-autonomous operation. The control structure is divided into two parts. First, it has an automatic task planner, which initialises actions on the symbolic level. The planner produces proactive robotic behaviours based on updated semantic knowledge. Second, it has an action executive for coordination actions at the level of sensing and actuation. The executive produces reactive behaviours in well-defined domains. The two parts are integrated by fuzzy logic based symbolic grounding. As a whole, they represent the framework for autonomous control. Based on the framework, SRS user interfaces are integrated on top of COB’s existing capabilities to enable robust fetch and carry in unstructured environments.
    • The development of a smart chair to assist sit-to-stand transferring process

      Lu, Hang; Li, Dayou; University of Bedfordshire (IEEE, 2014-07)
      Standing up from a seated position, known as sit-to-stand (STS) movement, is one of the activities of daily living (ADLs) on a daily basis. As people age, physiological changes occur including reduced muscle strength and mass as well as sensory capacity. This may lead to difficulties in STS transferring process, with which the elderly may encounter sedentary lifestyle and contracted social space. There exist market available assistive lift devices with performance far from satisfaction, for the reason being that they fail to provide appropriate assistance. Thus, an intent-based smart lift chair is proposed and partially developed aiming to analyse user's physiological condition through pattern recognition. The idea of assistance-as-needed is also introduced which may help encourage the elderly to improve their own motor function by offering personalised assistance with adaptation to the change of conditions.
    • Direct modification of silicon surface by nanosecond laser interference lithography

      Wang, Dapeng; Wang, Zuobin; Zhang, Ziang; Yue, Yong; Li, Dayou; Maple, Carsten (Elsevier, 2013)
      Periodic and quasi-periodic structures on silicon surface have numerous significant applications in photoelectronics and surface engineering. A number of technologies have been developed to fabricate the structures in various research fields. In this work, we take the strategy of direct nanosecond laser interference lithography technology, and focus on the silicon material to create different well-defined surface structures based on theoretical analysis of the formation of laser interference patterns. Two, three and four-beam laser interference systems were set up to fabricate the grating, regular triangle and square structures on silicon surfaces, respectively. From the AFM micrographs, the critical features of structures have a dependence on laser fluences. For a relative low laser fluence, grating and dot structures formed with bumps due to the Marangoni Effect. With the increase of laser fluences, melt and evaporation behaviors can be responsible for the laser modification. By properly selecting the process parameters, well-defined grating and dot structures can been achieved. It can be demonstrated that direct laser interference lithography is a facile and efficient technology with the advantage of a single process procedure over macroscale areas for the fabrication of micro and nano structures.
    • Effects of polarization on four-beam laser interference lithography

      Wang, Dapeng; Wang, Zuobin; Zhang, Ziang; Yue, Yong; Li, Dayou; Maple, Carsten; Changchun University of Science and Technology; University of Bedfordshire (American Institute of Physics, 2013)
      This paper demonstrates that polarization plays an important role in the formation of interference patterns, pattern contrasts, and periods in four-beam interference lithography. Three different polarization modes are presented to study the effects of polarization on four-beam laser interference based on theoretical analysis, simulations, and experiments. A four-beam laser interference system was set up to modify the silicon surface. It was found that the secondary periodicity or modulation was the result of the misaligned or unequal incident angles only in the case of the TE-TE-TM-TM mode. The resulting patterns have shown a good correspondence with the theoretical analysis and simulations.
    • Error factors affecting the result of Laser Interference Lithography

      Zhang, Jin; Jiang, Shilei; Tan, Chunlei; Wang, Zuobin; Li, Dayou; Yue, Yong; Qiu, Renxi; Sun, Guobin; Yang, Lihong; Wang, Sanlong; et al. (IEEE, 2013-08)
      Laser Interference Lithography (LIL) techniques enable quantitative generation of periodic structures such as array of holes, dots and lines, which are the intrinsic structure in some optical functional material. In this paper, the most common errors factors that could affect the result of laser interference lithography were presented. The methods to enhance the quality of patterns of LIL also have been introduced.
    • An evolutionary-based approach to learning multiple decision models from underrepresented data

      Schetinin, Vitaly; Li, Dayou; Maple, Carsten (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2008)
      The use of multiple Decision Models (DMs) enables to enhance the accuracy in decisions and at the same time allows users to evaluate the confidence in decision making. In this paper we explore the ability of multiple DMs to learn from a small amount of verified data. This becomes important when data samples are difficult to collect and verify. We propose an evolutionary-based approach to solving this problem. The proposed technique is examined on a few clinical problems presented by a small amount of data.
    • Fuzzy logic based symbolic grounding for best grasp pose for homecare robotics

      Liu, Beisheng; Li, Dayou; Yue, Yong; Maple, Carsten; Gu, Shuang; Qiu, Renxi; University of Bedfordshire (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012)
      Symbolic grounding in unstructured environments remains an important challenge in robotics [7]. Homecare robots are often required to be instructed by their human users intuitively, which means the robots are expected to take highlevel commands and execute corresponding tasks in a domestic environment. High-level commands are represented with symbolic terms such as “near” and “close” and, on the other hand, robots are controlled based on trajectories. The robots need to translate the symbolic terms to trajectories. In addition, domestic environment is unstructured where the same objects can be placed in different places over the time. This increases the difficulties in symbolic grounding. This paper presents a fuzzy logic based approach to symbolic grounding. In this approach, grounded concepts are modelled as fuzzy sets and the existing knowledge is used to deduce grounded values given real-time sensory inputs. Experiments results show that this approach works well in unstructured environment.
    • Fuzzy optimisation based symbolic grounding for service robots

      Liu, Beisheng; Li, Dayou; Qiu, Renxi; Yue, Yong; Maple, Carsten; Gu, Shuang; University of Bedfordshire (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012)
      Symbolic grounding is a bridge between high-level planning and actual robot sensing, and actuation. Uncertainties raised by the unstructured environment make a bottleneck for integrating traditional artificial intelligence with service robotics. This paper presents a fuzzy logic based approach to formalise the grounding problems into a fuzzy optimization problem, which is robust to uncertainties. Novel techniques are applied to establish the objective function, to model fuzzy constraints and to perform fuzzy optimisation. The outcome is tested with a service robot fetch and carry task, where the fuzzy optimisation approach helps the robot to determine the most comfortable position (location and orientation) for grasping objects. Experimental results show that the proposed approach improves the robustness of the task implementation in unstructured environments.
    • GC/MS data reduction using retention time alignment and spectral subtraction

      Hitchcock, Jonathan James; Li, Dayou; Maple, Carsten; Keech, Malcolm; Teale, Phil; Hudson, Simon; University of Bedfordshire; HFL Ltd (British Mass Spectrometry Society, 2007-09-10)
      The identification of chemical compounds in a complex mixture is a challenge. In the context of drug surveillance for the sporting world, large-scale screening of urine and blood samples is undertaken using methods such as GC/MS with low-resolution mass spectrometers that measure integer values of m/z ratio. The analysis of the GC/MS data can be automated using standard mass spectrometry software to detect peaks in the chromatograms and to search a library of mass spectra of known drugs. Because of noise and the presence of co-eluting compounds, the mass spectra are usually not exactly the same as those in the library. The match quality for a genuine match can be quite low, and the library search settings must be sufficiently sensitive so as not to miss positive samples. Therefore many false matches are reported for checking and validation by human analysts, and, since almost all the samples are negative, this process of checking is tedious, time-consuming and cost-inefficient. The usual technique to remove unwanted background is to subtract the spectrum of an adjacent scan of the same sample. Our proposed method instead subtracts the spectrum of a second similar sample. The intention is that any contributions from a substance common to the two samples will be eliminated, and that any substance that is in the first sample but not in the second will still be recorded in the subtracted dataset. Assuming a suitable second sample is available that does not contain banned substances, those that are present in the first sample can be more easily detected. The subtraction is applied to each scan of the test sample. For this to work, it is essential that retention times are precisely aligned so that a corresponding scan of the second sample can be chosen. Although many methods of alignment are described in the literature, simple linear alignment based on a correlation measure is found to be sufficient. It is also necessary to scale the spectra being subtracted to allow for differences between the two samples in the concentration of the common compounds. Subtracting a similar dataset will reduce the number of peaks to be considered, and our hypothesis is that a library search of the resulting dataset will produce a smaller number of false matches than the same library search applied to the original data. An experiment was carried out to test this and the number of false matches was indeed found to be reduced. The more similar the second sample was to the first, the better was the result. It was also verified that true matches of compounds of interest are still reported by the library search of the subtracted data.
    • Genetic algorithm based solution to dead-end problems in robot navigation

      Kang, Xiaoming; Yue, Yong; Li, Dayou; Maple, Carsten (Inderscience, 2011)
      In robot navigation, mobile robots can suffer from dead-end problems, that is, they can be stuck in areas which are surrounded by obstacles. Attempts have been reported to avoid a robot entering into such a dead-end area. However, in some applications, for example, rescue work, the dead-end areas must be explored. Therefore, it is vital for the robot to come out from the dead-end areas after exploration. This paper presents an approach which enables a robot to come out from dead-end areas. There are two main parts: a dead-end detection mechanism and a genetic algorithm (GA) based online training mechanism. When the robot realises that it is stuck in a dead-end area, it will operate the online training to produce a new best chromosome that will enable the robot to escape from the area.
    • Integration of symbolic task planning into operations within an unstructured environment

      Qiu, Renxi; Noyvirt, Alexandre; Ji, Ze; Soroka, Anthony; Li, Dayou; Liu, Beisheng; Arbeiter, Georg; Weisshardt, Florian; Xu, Shuo (IGI Global, 2012)
      To ensure a robot capable of robust task execution in unstructured environments, task planners need to have a high-level understanding of the nature of the world, reasoning for deliberate actions, and reacting to environment changes. Proposed is a practical task planning approach that seamlessly integrating deeper domain knowledge, real time perception and symbolic planning for robot operation. A higher degree of autonomy under unstructured environment will be endowed to the robot with the proposed approach.
    • K-order surrounding roadmaps path planner for robot path planning

      Li, Yueqiao; Li, Dayou; Maple, Carsten; Yue, Yong; Oyekan, John O. (Springer, 2014-09)
      Probabilistic roadmaps are commonly used in robot path planning. Most sampling-based path planners often produce poor-quality roadmaps as they focus on improving the speed of constructing roadmaps without paying much attention to the quality. Poor-quality roadmaps can cause problems such as poor-quality paths, time-consuming path searching and failures in the searching. This paper presents a K-order surrounding roadmap (KSR) path planner which constructs a roadmap in an incremental manner. The planner creates a tree while answering a query, selects the part of the tree according to quality measures and adds the part to an existing roadmap which is obtained in the same way when answering the previous queries. The KSR path planner is able to construct high-quality roadmaps in terms of good coverage, high connectivity, provision of alternative paths and small size. Comparison between the KSR path planner and Reconfigurable Random Forest (RRF), an existing incremental path planner, as well as traditional probabilistic roadmap (PRM) path planner shows that the roadmaps constructed using the KSR path planner have higher quality that those that are built by the other planners.
    • Magnetic surface patterns made by non-destructive laser interference

      Hou, Yu; Wang, Zuobin; Song, Jiaojiao; Li, Dayou; Yue, Yong; Maple, Carsten; Changchun University of Science and Technology; University of Bedfordshire (IEEE, 2013-08)
      This paper presents a method to make magnetic surface patterns by non-destructive laser interference, and periodic magnetic fringes produced on magnetic material surfaces are investigated by magnetic force microscopy (MFM). Various thermal effects are obtained by two beam laser interference with different exposure times and pulse energies. The experimental results have shown that magnetic patterns can be made on magnetic materials by laser interference without any damage to the surfaces. The method provides a way for the rapid producing of magnetic marks or recording magnetic data in a large area on a magnetic material surface, and it could be useful for biological, material, optical, electronic and information engineering applications.
    • A norm optimal iterative learning control based train trajectory tracking approach

      Sun, Heqing; Hou, Zhongsheng; Li, Dayou (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012)
      A norm optimal iterative learning control (NOILC) is proposed and applied in train trajectory tracking problem, and it then is extended to the cases with traction/braking constraint. Rigorous theoretical analysis has shown that the proposed approach can guarantee the asymptotic convergence of train speed and position to desired profiles as iteration number goes infinity. Simulation results further demonstrate the effectiveness of the proposed NOILC approach.