Top PDF A Semi-autonomous Wheelchair Navigation System

A Semi-autonomous Wheelchair Navigation System

A Semi-autonomous Wheelchair Navigation System

The first documented discovery of electro-encephalogram (EEG) signals dates back to 1875 [23]. Since then, research to implement control of a machine via ‘brain waves’ has been pursued. However, only recently have developments yielded one of the first practical uses of EEG. A collaborative effort between RIKEN, Toyota, Genesis Research Institute and other groups developed a system which uses EEG to control a wheelchair [24]. The technology is reported to be capable of detecting a user’s driving directives at 8 Hz with a 95 % accuracy rate [24], making it suitable for real- time control of a wheelchair. However, this technology is still in development. It also involves several hours of training the user how to think of a certain command before the system can be used. It is also likely that the commands that can be decoded from the EEG signals are primitive, and unlike speech control, limited to simple directives such as left, right, forward, reverse and other trained thought commands. A somewhat critical view on the brain-machine interface is provided by Felzer and Nordman [18]. Since the EEG signal is sensitive to all human actions (e.g., blinking, swallowing, laughing, talking), it is likely that in practice the resulting wheelchair command would be highly contaminated [18].
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A semi-autonomous framework for human-aware and user intention driven wheelchair mobility assistance

A semi-autonomous framework for human-aware and user intention driven wheelchair mobility assistance

Abstract— An important aspect to be taken care of while designing assistive robots for mobility is that they need to op- erate among humans. Thus understanding human spatial social conventions and incorporating them in the assistive solutions, is important. In this paper, we introduce a semi-autonomous framework for assistive wheelchair navigation in human envi- ronments, which is driven by the intention of the wheelchair user. Safe and socially compliant motion provided by a user intention driven local motion planner is fused with user teleoperation in order to create such a system. Taking into account the fact that the user is the primary controller, our proposed system aims to provide progressive assistance whenever the user is in danger of collision or at risk of disturbance to other humans. We also thus propose generalized formulations for estimating user intentions and for sharing control within the context of wheelchair mobility assistance, that is adaptable in order to be deployed in real world systems. We then evaluate the proposed framework in simulation in order to obtain a quantitative analysis. We also provide experimental evidence using an off-the-shelf robotized wheelchair equipped with a single 2D laser scanner.
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Vision-based Indoor Navigation of a Semi-autonomous and Interactive  Unmanned Aerial System

Vision-based Indoor Navigation of a Semi-autonomous and Interactive Unmanned Aerial System

For government-military related missions, the roles for the UAS pilots are significant to operate the UAS missions. However, operating the UAS with a group of pilots have difficulties due to human factors such as fatigue, miscommunication, attention, and workload [2] . To reduce the load of pilots and augment the performance of the UAS operations, based on a study by Drury, a detailed framework system that can manage the amount of mission flight information and transfer it to the operators was proposed [3] . For example, by authorizing an UAS to sufficiently handle necessary tasks such as autonomous obstacle avoidance, the information load for human pilots can be reduced. In a study by Call et al., it has been shown that an UAS can avoid obstacles using vision sensors [4] .
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Bilateral Human Robot Control for Semi Autonomous UAV Navigation

Bilateral Human Robot Control for Semi Autonomous UAV Navigation

In traded-control, control efforts are shifted between the human operator and the autonomous controller, which can be either a part or the total control effort. One of the main types of semi-autonomous traded-control is the mixed-initiative-interaction (MII) method [8]. MII is a flexible interaction strategy, in which the task at hand determines which actor should contribute to which control effort. In certain applications the autonomous controller can lead [9] [10], where the human operator takes over if the situation requires this (e.g. a ground robot that gets stuck in unequal terrain and needs a complex control strategy to get loose). Often in this case, the human overtakes the complete control effort. Other applications can be led by the human, where the autonomous controller takes over in case necessary (e.g. driving a vehicle with safety-systems which are activated if the task diverges from regular driving to avoiding an accident). Results in research show that traded-control, in complex scenarios, can reduce the overall immobility time to a comparable amount of autonomous control, while it can increase the coverage in exploring an area to be comparable to that of pure teleoperation [11]. However, in switching the control effort, there can be some undesired switching behavior temporarily reducing stability. Furthermore, both operators need to be standby. Also, the human requires high environmental awareness to properly take over the control actions. This is undesirable in the SHERPA scenario for two reasons. First, as the operator is busy traversing the difficult terrain, the operator cannot be distracted too much by keeping track of the UAVs. Second, UAVs are intrinsically unstable, which means that small mistakes can have big consequences, and undesired switching behavior can be fatal to the system.
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A Semi-supervised Approach for Improving Search, Navigation and Data Quality in Autonomous Digital Libraries

A Semi-supervised Approach for Improving Search, Navigation and Data Quality in Autonomous Digital Libraries

PageRank has been very successful in ranking web pages, essentially con- sidering the reputation of the web page referring to a given page, and the outgoing link density (pages P linked by pages L where L has few outgo- ing links are considered more important than pages P cited by pages L where L has many outgoing links). Paper Rank (PR) applies page rank to papers by considering papers as web pages and citations as links, and hence trying to consider not only citations when ranking papers, but also taking into account the rank of the citing paper and the density of out- going citations from the citing paper. From a computation perspective, PR is different from Page Rank in that loops are very rare, almost inexis- tent. Situations with loop where a paper A cites a paper B and B cites A are possible when authors exchange their working versions and cite papers not yet published but accepted for publication. In our dataset, we have removed these few loops (around 200 loops in our set). That is why the Markov matrix may be brought to diagonal form like it is explained in the work of Lee Giles [87], so the system will have solution even without damp factor. We decided to omit the damp factor and take the 4.1 for PR computation. Furthermore, considering that a citation graph has N >> 1 nodes (papers), each paper may potentially have from 1 to N − 1 inbound links and the same quantity of outgoing ones. However, in practice citation graphs are extremely sparse, (articles in our ACM dataset normally have from 5 to 20 references 1 ) and this impact the speed of the computation of
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An Autonomous Wheelchair with Indoor Positioning System and Smart 3D Headphone for the Visually Impaired

An Autonomous Wheelchair with Indoor Positioning System and Smart 3D Headphone for the Visually Impaired

Figures 14–16 illustrate scans of a person making a hand gesture movement, a semi-closed door, and a closed door, respectively. The 3D objects are shown in the left, the scanned images converted into frequency sounds in the right (a different color for each frequency) and the generated sound amplitude below (delivered to 6 different pair of speakers). The colored points of the scanned images represent sounds of different frequencies, for all layers. Comparing these three figures, we observe that the more the variation in depth, the longer the duration of sound. After some training, using the 3D headphone of Figure 4, a blind person was able to easily recognize the three different objects. However, it may be possible to recognize other objects if intensive training is provided. In this paper we proposed a solution to convert 3D objects into sound to give visually impaired people an idea of what an object looks like and how distant it is. Compared to other solutions that use 2D images, the use of a 3D object gives us a better understanding of that object. Instead of using the intensity of the pixels of an image to generate a sound to describe the image, our method (pending patent [41]) uses separate layers of the object to give visually impaired people a better understanding of the object’s shape and depth.
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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

4. CONCLUSION AND PERSPECTIVES In this paper, a pilot study was conducted to assess the influence of fatigue on SSVEP over 14 EEG sensors. From the 70 overall parameters, only 5 correlate significantly with subjective ratings. Those occur essentially in the visual cortex, but found that the parietal lobe also correlates significantly in Alpha and Beta band waves while Delta, Theta and Gamma doesn’t show any interesting results. As mentioned before, the goal of the current study is to seek the needed parameters to switch between manual, semi-autonomous, and autonomous wheelchair command. Another EEG component can be integrated to estimate fatigue state, is the Positive 300 (P300). In fact many studies showed the influence of fatigue on P300 (see [19] and [20]), as well as its efficiency as a BCI source of control.
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Intelligent Autonomous Wheelchair for Indoor Navigation

Intelligent Autonomous Wheelchair for Indoor Navigation

A wide variety of assisted wheelchair navigation systems have been developed over the past 30 years. Low- cost solutions are generally either limited and semi- autonomous [6] [11], or require an external localization system [8], or lack global localization planning capabilities. Maya Burhanpurkar et al., 2017 [5] presented a cost- effective and robust autonomous navigation system for existing PWs.[7] According to the paper, based on an inexpensive sensor suite (an RGB-D sensor and wheel odometry), the various modules of the system (Simultaneous Localization and Mapping (SLAM), navigation, and door traversal) functioned synergistically to enable reliable operation under real-world conditions. Zhengang Li et al., 2017 [9] presented a wheelchair which adopts two-wheel differential control structure and used RGB-D camera to perceive the environment. [10] The position and orientation of wheelchair was estimated by Adaptive Monte Carlo Localization (AMCL) algorithm. A* algorithm was applied for global path planning and Dynamic Window Approach (DWA) algorithm was used for local path planning.[12] Their experimental results were consistent with the experimental expectation.
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Human-in-the-Loop Cyber Physical Systems: Modular Designs for Semi-Autonomous Wheelchair Navigation

Human-in-the-Loop Cyber Physical Systems: Modular Designs for Semi-Autonomous Wheelchair Navigation

Recognizing that the aging population has diverse and dynamic needs, CanChair will also attempt to develop and release common hardware and software design platforms which will others to easily customize commercially available wheelchairs to individual users and adapt the wheelchair as the user ages. CanChair predicts these platforms will “make it easier for researchers and commercial developers to add new capabilities, sensors and interfaces, as well as to migrate to new computer and wheelchair models as they become available”. It is clear that they believe a highly customizable, modular design will rapidly accelerate the advancement of smart wheelchair technologies. CanWheel also intends to create multiple prototypes of smart wheelchairs in order to obtain feedback from a broad range of stakeholders throughout the project. The feedback collected will serve as a starting point for future commercialization efforts and additional studies. An example of one of their prototype smart wheelchair is shown in Figure 4.
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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

The MARCH tests cannot be applied to the embedded RAM through the chip's I/O pins, because the address, data, and control signals are not directly available through these I/O pins. Hence, the best test solution for the embedded RAM is by using built-in self-test (BIST). Typically, the BIST is designed based on the deterministic patterns such as MARCH test. This MARCH test is generally programmed inside the BIST engine. This BIST engine is basically divided into two types: state- machine and micro-code [11]. A state-machine (also known as finite state-machine (FSM)) memory BIST (MBIST) is generally used in the industry to generate a single MARCH test. However, a better memory test solution requires a set of multiple MARCH tests. This certainly increases the complexity of the MBIST design. A state-machine BIST, as the name implies, uses a number of states, to decode the MARCH test [12]. However, the state- machine MBIST is less flexible as modifying the patterns requires major changes in the MBIST design. As for the micro-code BIST, the test patterns are inserted into the controller in the form of instruction sets. This type of MBIST is highly flexible because different MARCH tests can be utilized. It can also be used in both manufacturing and in a system environment. Both FSM-based and microcode-based MBIST controllers must be able to generate different types of MARCH tests [12]. This can be accomplished by using a programmable architecture. Both types of MBIST: state-machines and micro-code can be designed to be a programmable memory built-in self-test (P- MBIST).
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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

DS based Intelligent flooding Algorithm 4.1 DSGM Forwarding A location based protocol [5] can be used to forward the Geo message from the source node to the boundary face node.. A node o[r]

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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

We investigate the effect of propagation model both non-fading and fading and mobility on the performance of the ad hoc routing protocol such as Ad hoc On Demand Distance Vector AODV, Dy[r]

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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

Section 7 shows the results of the proposed adaptive encoding technique for enhanced multispectral images and comparative analysis is based on PSNR, compression ratio, bits per pixel and[r]

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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

logarithmic number system (2DLNS) processing structure. The data were split into a number of smaller sections, where each section was converted to a 2-digit 2DLNS (2 bases) representation. The dynamic range reduction and logarithmic characteristics of computing with two orthogonal base exponents in that number system allowed multiplication to be implemented with simple parallel small adders. Their architectures were able to perform single and double precision multiplications, as well as fault tolerant and dual throughput single precision operations. The implementations demonstrate the efficiency of 2DLNS in multiplication intensive DSP applications and exhibited outstanding results in terms of operation delay and dynamic power consumption.
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Intelligent traffic sign recognition system for autonomous vehicle navigation (ITSRS)

Intelligent traffic sign recognition system for autonomous vehicle navigation (ITSRS)

Computer vision is a technology and technique to help computer to become high- level understanding from some data sources such as images, videos and many more. The computer with computer vision can even achieve what our human visual system can do. Artificial intelligent has recently become a trend in all fields. Especially for industry field, the industry who uses automation production is getting more. A computer is always ready to follow command and instruction from the user to start working on the production. It can understand human’s natural language like talking to people, but we are not. This scenario shows how amazing an artificial intelligent technology has been applied in the industry aspect and it also proves that the technology nowadays is enough mature to be implemented in our daily life like driving.
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Semantic Segmentation to Develop an Indoor Navigation System for an Autonomous Mobile Robot

Semantic Segmentation to Develop an Indoor Navigation System for an Autonomous Mobile Robot

The results in Figure 17a show the improvement in the speed calculation with a mean of 0.0987 s. The other GPU is an Asus GeForce GTX 660 Ti with 1344 CUDA cores and 2 GB DDR5 with 144.2 Gb/s bandwidth. Comparing the characteristics, the Asus GPU has a better CUDA cores and a higher bandwidth. However, its available memory is 2 GB less in the second computer. The results for the Asus reveal that a GPU with more CUDA cores and a memory interface, which is 128 bits in the Quadro and 192 bits in the Asus, help to compute ResNet-18 faster. The mean of this execution is 0.0615 s, which is 0.03 s faster. Therefore, this Neural Network can work with 16 Hz, which is close to the value of industrial navigation systems. Due to its CPU and other hardware components, the Asus computer also finished image processing more quickly.
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Visual Navigation of an autonomous drone

Visual Navigation of an autonomous drone

The idea of autonomous precision landing was based on issues the electric power company Trønder Energi had with landing their radio controlled drones used for surveillance of power grids should land on a trailer. The motivation choosing this goal was after some research found that this is a missing feature in most commercial available drones today within the price range of $1000. Limited battery power is one of the main limitations of drones today, usual flight time of these kind drones today is about 10 to 25 minutes depending on their current pay load. This feature possibly enable drones to land on charging station and make them completely autonomous. Autonomous drone with this feature can possibly
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Haptic interfaces for wheelchair navigation in the built environment

Haptic interfaces for wheelchair navigation in the built environment

platform, this data relating to the individual incremental angular displacement of both wheels on the motion platform. The current data values are compared to the previous increment, to determine whether either wheel is rotated forward or backward, this information then being passed to the next stage of the algorithm. The basis of the motion control algorithm is the determination, through an analysis of similar triangles, of any translation and also, using the location of the centre of rotation along the rear axle of the virtual wheelchair, the angle through which is turned. These values are passed to the graphics system where the transformation of the eye point and rotation of the view vector can be determined. As the angular motion of the rollers is used to calculate wheelchair displacement the motion of the visual field can be calibrated in relation to actual displacement. Feedback from the graphics system determines whether the brakes, clutch or motors should be actuated to provide a physical level of feedback to the user.
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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

Spatial domain watermarking techniques offer number of advantages. These schemes are often fragile and hence mainly used for tamper detection and for content authentication. In spatial domain schemes the watermark is directly embedded by modifying the pixels of the original image without applying any transformation. Hence these schemes are computationally less complex. One such technique proposed by Sudeb Das and Malay Kumar Kundu [80] incorporates ROI protection and tamper detection mechanism. Two different watermarks are embedded in the medical image. One is encrypted EPR/DICOM metadata, keywords, Doctors ID, ROI information and other support information. The second watermark is binary location map, which is used for tamper detection and localization. The watermark is dispersed using one-to-one mapping function. AES, SHA256 and arithmetic coding are used to enhance the security of the system. Performance is measured for images in 7 different modalities in different formats in different bit depth and different sizes. The authors claim that their mechanism achieved superior tamper localization capability, higher capacity and imperceptibility. The method is relatively simple and consumes less time for archiving and retrieval. However two bit planes are used for embedding which results in image degradation.
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 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

 EFFECT OF FATIGUE ON SSVEP DURING VIRTUAL WHEELCHAIR NAVIGATION

Experimental results using 44 slice CT scans of 20 patients can be seen that ASM method has high accuracy for segmentation of lung fields,, especially lung containing abnormalities nodul[r]

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