746 research outputs found
Planetary rovers and data fusion
This research will investigate the problem of position estimation for planetary rovers.
Diverse algorithmic filters are available for collecting input data and transforming
that data to useful information for the purpose of position estimation process. The
terrain has sandy soil which might cause slipping of the robot, and small stones and
pebbles which can affect trajectory.
The Kalman Filter, a state estimation algorithm was used for fusing the sensor data
to improve the position measurement of the rover. For the rover application the
locomotion and errors accumulated by the rover is compensated by the Kalman
Filter. The movement of a rover in a rough terrain is challenging especially with
limited sensors to tackle the problem. Thus, an initiative was taken to test drive
the rover during the field trial and expose the mobile platform to hard ground and
soft ground(sand). It was found that the LSV system produced speckle image and
values which proved invaluable for further research and for the implementation of
data fusion.
During the field trial,It was also discovered that in a at hard surface the problem
of the steering rover is minimal. However, when the rover was under the influence
of soft sand the rover tended to drift away and struggled to navigate.
This research introduced the laser speckle velocimetry as an alternative for odometric
measurement. LSV data was gathered during the field trial to further simulate under
MATLAB, which is a computational/mathematical programming software used for
the simulation of the rover trajectory. The wheel encoders came with associated
errors during the position measurement process. This was observed during the
earlier field trials too. It was also discovered that the Laser Speckle Velocimetry
measurement was able to measure accurately the position measurement but at the
same time sensitivity of the optics produced noise which needed to be addressed as
error problem.
Though the rough terrain is found in Mars, this paper is applicable to a terrestrial
robot on Earth. There are regions in Earth which have rough terrains and regions
which are hard to measure with encoders. This is especially true concerning icy
places like Antarctica, Greenland and others.
The proposed implementation for the development of the locomotion system is to
model a system for the position estimation through the use of simulation and collecting data using the LSV. Two simulations are performed, one is the differential
drive of a two wheel robot and the second involves the fusion of the differential drive
robot data and the LSV data collected from the rover testbed. The results have
been positive. The expected contributions from the research work includes a design
of a LSV system to aid the locomotion measurement system.
Simulation results show the effect of different sensors and velocity of the robot. The
kalman filter improves the position estimation process
Advanced sensors technology survey
This project assesses the state-of-the-art in advanced or 'smart' sensors technology for NASA Life Sciences research applications with an emphasis on those sensors with potential applications on the space station freedom (SSF). The objectives are: (1) to conduct literature reviews on relevant advanced sensor technology; (2) to interview various scientists and engineers in industry, academia, and government who are knowledgeable on this topic; (3) to provide viewpoints and opinions regarding the potential applications of this technology on the SSF; and (4) to provide summary charts of relevant technologies and centers where these technologies are being developed
MultiIoT: Towards Large-scale Multisensory Learning for the Internet of Things
The Internet of Things (IoT), the network integrating billions of smart
physical devices embedded with sensors, software, and communication
technologies for the purpose of connecting and exchanging data with other
devices and systems, is a critical and rapidly expanding component of our
modern world. The IoT ecosystem provides a rich source of real-world modalities
such as motion, thermal, geolocation, imaging, depth, sensors, video, and audio
for prediction tasks involving the pose, gaze, activities, and gestures of
humans as well as the touch, contact, pose, 3D of physical objects. Machine
learning presents a rich opportunity to automatically process IoT data at
scale, enabling efficient inference for impact in understanding human
wellbeing, controlling physical devices, and interconnecting smart cities. To
develop machine learning technologies for IoT, this paper proposes MultiIoT,
the most expansive IoT benchmark to date, encompassing over 1.15 million
samples from 12 modalities and 8 tasks. MultiIoT introduces unique challenges
involving (1) learning from many sensory modalities, (2) fine-grained
interactions across long temporal ranges, and (3) extreme heterogeneity due to
unique structure and noise topologies in real-world sensors. We also release a
set of strong modeling baselines, spanning modality and task-specific methods
to multisensory and multitask models to encourage future research in
multisensory representation learning for IoT
Large scale modeling, model reduction and control design for a real-time mechatronic system
Mechatronics is the synergistic integration of the techniques from mechanical engineering, electrical engineering and information technology, which influences each other mutually. As a multidisciplinary domain, mechatronics is more than mechanical or electronics, and the mechatronic systems are always composed of a number of subsystems with various controllers. From this point of view, a lot of such systems can be defined as large scale system. The key element of such systems is integration. Modeling of mechatronic system is a very important step in developing control design of such products, so as to simulate and analyze their dynamic responses for control design, making sure they would meet the desired requirements. The models of large scale systems are always resulted in complex form and high in dimension, making the computation for modeling, simulation and control design become very complicated, or even beyond the solutions provided by conventional engineering methods. Therefore, a simplified model obtained by using model order reduction technique, which can preserve the dominant physical parameters and reveal the performance limiting factor, is preferred. In this dissertation, the research have chosen the two-wheeled self-balancing scooter as the subject of the study in research on large scale mechatronic system, and efforts have been put on developing a completed mathematical modeling method based on a unified framework from varitional method for both mechanical subsystem and electrical subsystem in the scooter. In order to decrease the computation efforts in simulation and control design, Routh model reduction technique was chosen from various model reduction techniques so as to obtain a low dimensional model. Matlab simulation is used to predict the system response based on the simplified model and related control design. Furthermore, the final design parameters were applied in the physical system of two-wheeled self-balancing scooter to test the real performance so as to finish the design evaluation. Conclusion was made based on these results and further research directions can be predicte
MEMS Accelerometers
Micro-electro-mechanical system (MEMS) devices are widely used for inertia, pressure, and ultrasound sensing applications. Research on integrated MEMS technology has undergone extensive development driven by the requirements of a compact footprint, low cost, and increased functionality. Accelerometers are among the most widely used sensors implemented in MEMS technology. MEMS accelerometers are showing a growing presence in almost all industries ranging from automotive to medical. A traditional MEMS accelerometer employs a proof mass suspended to springs, which displaces in response to an external acceleration. A single proof mass can be used for one- or multi-axis sensing. A variety of transduction mechanisms have been used to detect the displacement. They include capacitive, piezoelectric, thermal, tunneling, and optical mechanisms. Capacitive accelerometers are widely used due to their DC measurement interface, thermal stability, reliability, and low cost. However, they are sensitive to electromagnetic field interferences and have poor performance for high-end applications (e.g., precise attitude control for the satellite). Over the past three decades, steady progress has been made in the area of optical accelerometers for high-performance and high-sensitivity applications but several challenges are still to be tackled by researchers and engineers to fully realize opto-mechanical accelerometers, such as chip-scale integration, scaling, low bandwidth, etc
Kinematic State Estimation using Multiple DGPS/MEMS-IMU Sensors
Animals have evolved over billions of years and understanding these complex and intertwined systems have potential to advance the technology in the field of sports science, robotics and more. As such, a gait analysis using Motion Capture (MOCAP) technology is the subject of a number of research and development projects aimed at obtaining quantitative measurements. Existing MOCAP technology has limited the majority of studies to the analysis of the steady-state locomotion in a controlled (indoor) laboratory environment. MOCAP systems such as the optical, non-optical acoustic and non-optical magnetic MOCAP systems require predefined capture volume and controlled environmental conditions whilst the non-optical mechanical MOCAP system impedes the motion of the subject. Although the non-optical inertial MOCAP system allows MOCAP in an outdoor environment, it suffers from measurement noise and drift and lacks global trajectory information. The accuracy of these MOCAP systems are known to decrease during the tracking of the transient locomotion. Quantifying the manoeuvrability of animals in their natural habitat to answer the question “Why are animals so manoeuvrable?” remains a challenge. This research aims to develop an outdoor MOCAP system that will allow tracking of the steady-state as well as the transient locomotion of an animal in its natural habitat outside a controlled laboratory condition. A number of researchers have developed novel MOCAP systems with the same aim of creating an outdoor MOCAP system that is aimed at tracking the motion outside a controlled laboratory (indoor) environment with unlimited capture volume. These novel MOCAP systems are either not validated against the commercial MOCAP systems or do not have comparable sub-millimetre accuracy as the commercial MOCAP systems. The developed DGPS/MEMS-IMU multi-receiver fusion MOCAP system was assessed to have global trajectory accuracy of _0:0394m, relative limb position accuracy of _0:006497m. To conclude the research, several recommendations are made to improve the developed MOCAP system and to prepare for a field-testing with a wild animal from a family of a terrestrial megafauna
Neurological Tremor: Sensors, Signal Processing and Emerging Applications
Neurological tremor is the most common movement disorder, affecting more than 4% of elderly people. Tremor is a non linear and non stationary phenomenon, which is increasingly recognized. The issue of selection of sensors is central in the characterization of tremor. This paper reviews the state-of-the-art instrumentation and methods of signal processing for tremor occurring in humans. We describe the advantages and disadvantages of the most commonly used sensors, as well as the emerging wearable sensors being developed to assess tremor instantaneously. We discuss the current limitations and the future applications such as the integration of tremor sensors in BCIs (brain-computer interfaces) and the need for sensor fusion approaches for wearable solutions
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