Active Assistive Orthotic System

Author(s):  
Ivanka Petkova Veneva ◽  
Dimitar Chakarov ◽  
Mihail Tsveov ◽  
Dimitar Stefanov Trifonov ◽  
Evgeni Zlatanov ◽  
...  

Active orthosis (exoskeleton) is an assistive device with a wearable structure, corresponding to the natural motions of the human. This chapter focuses on developing an active/assistive orthosis system (AOS) enhancing movement. The AOS design is inspired by the biological musculoskeletal system of human upper and lower limbs and mimics the muscle-tendon-ligament structure. The exoskeleton structure includes left and right upper limb, left and right lower limb, and central exoskeleton structure for human torso and waist and provides support, balance, and control of different segments of the body. The device was fabricated with light materials and powered by pneumatic artificial muscles that provide more than fifteen degrees of freedom for the different joints. The active orthotic systems (AOS) can operate in three modes: motion tracking system with data exchange with virtual reality; haptic and rehabilitation device; and assistive mode with active orthosis in cases of impaired muscles.

Author(s):  
Ivanka Petkova Veneva ◽  
Dimitar Chakarov ◽  
Mihail Tsveov ◽  
Dimitar Stefanov Trifonov ◽  
Evgeni Zlatanov ◽  
...  

Active orthosis (exoskeleton) is an assistive device with a wearable structure, corresponding to the natural motions of the human. This chapter focuses on developing an active/assistive orthosis system (AOS) enhancing movement. The AOS design is inspired by the biological musculoskeletal system of human upper and lower limbs and mimics the muscle-tendon-ligament structure. The exoskeleton structure includes left and right upper limb, left and right lower limb, and central exoskeleton structure for human torso and waist and provides support, balance, and control of different segments of the body. The device was fabricated with light materials and powered by pneumatic artificial muscles that provide more than fifteen degrees of freedom for the different joints. The active orthotic systems (AOS) can operate in three modes: motion tracking system with data exchange with virtual reality; haptic and rehabilitation device; and assistive mode with active orthosis in cases of impaired muscles.


2019 ◽  
Vol 39 (2-3) ◽  
pp. 163-182 ◽  
Author(s):  
Nikhil Chavan-Dafle ◽  
Rachel Holladay ◽  
Alberto Rodriguez

In this article, we present the mechanics and algorithms to compute the set of feasible motions of an object pushed in a plane. This set is known as the motion cone and was previously described for non-prehensile manipulation tasks in the horizontal plane. We generalize its construction to a broader set of planar tasks, such as those where external forces including gravity influence the dynamics of pushing, or prehensile tasks, where there are complex frictional interactions between the gripper, object, and pusher. We show that the motion cone is defined by a set of low-curvature surfaces and approximate it by a polyhedral cone. We verify its validity with thousands of pushing experiments recorded with a motion tracking system. Motion cones abstract the algebra involved in the dynamics of frictional pushing and can be used for simulation, planning, and control. In this article, we demonstrate their use for the dynamic propagation step in a sampling-based planning algorithm. By constraining the planner to explore only through the interior of motion cones, we obtain manipulation strategies that are robust against bounded uncertainties in the frictional parameters of the system. Our planner generates in-hand manipulation trajectories that involve sequences of continuous pushes, from different sides of the object when necessary, with 5–1,000 times speed improvements to equivalent algorithms.


2012 ◽  
Vol 22 (05) ◽  
pp. 1250019 ◽  
Author(s):  
LUIS QUESADA ◽  
ALEJANDRO J. LEÓN

Motion tracking is a critical task in many computer vision applications. Existing motion tracking techniques require either a great amount of knowledge on the target object or specific hardware. These requirements discourage the wide spread of commercial applications based on motion tracking. In this paper, we present a novel three degrees of freedom motion tracking system that needs no knowledge on the target object and that only requires a single low-budget camera that can be found installed in most computers and smartphones. Our system estimates, in real time, the three-dimensional position of a nonmodeled unmarked object that may be nonrigid, nonconvex, partially occluded, self-occluded, or motion blurred, given that it is opaque, evenly colored, enough contrasting with the background in each frame, and that it does not rotate. Our system is also able to determine the most relevant object to track in the screen. Our proposal does not impose additional constraints, therefore it allows a market-wide implementation of applications that require the estimation of the three position degrees of freedom of an object.


2018 ◽  
Vol 30 (3) ◽  
pp. 453-466 ◽  
Author(s):  
Shaopeng Hu ◽  
◽  
Mingjun Jiang ◽  
Takeshi Takaki ◽  
Idaku Ishii

In this study, we developed a monocular stereo tracking system to be used as a marker-based, three-dimensional (3-D) motion capture system. This system aims to localize dozens of markers on multiple moving objects in real time by switching five hundred different views in 1 s. The ultrafast mirror-drive active vision used in our catadioptric stereo tracking system can accelerate a series of operations for multithread gaze control with video shooting, computation, and actuation within 2 ms. By switching between five hundred different views in 1 s, with real-time video processing for marker extraction, our system can function asJvirtual left and right pan-tilt tracking cameras, operating at 250/Jfps to simultaneously capture and processJpairs of 512 × 512 stereo images with different views via the catadioptric mirror system. We conducted several real-time 3-D motion experiments to capture multiple fast-moving objects with markers. The results demonstrated the effectiveness of our monocular 3-D motion tracking system.


Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S209-S221
Author(s):  
Lu Han ◽  
Hechen Zhang ◽  
Zhongxia Xiang ◽  
Jinze Shang ◽  
Shabila Anjani ◽  
...  

BACKGROUND: The contrast between a bright computer screen and a dark ambient environment may influence comfort of the users, especially on their eyes. OBJECTIVE: The objective of this research is to identify the optimal desktop lighting for the comfortable use of the computer screen in a dark environment. METHODS: An experiment was designed where seven illumination setups were introduced for the users to perform their leisure tasks on a computer screen. Fifteen healthy subjects participated in the experiments. During each session, durations of the eye blinks, fixations and saccades of the user were recorded by an eye tracker. His/her neck and trunk movements were recorded by a motion tracking system as well. The comfort/discomfort questionnaire, localized postural discomfort questionnaire, NASA task load index and computer user questionnaire were used to record the overall comfort/discomfort, the local perceived physical discomfort, the cognitive workload, and general/eye health problems, respectively. RESULTS: Subjective and objective measurement results indicated that users felt more comfortable with high intensity warm lights using a computer screen. We also identified that the eye fixation durations, as well as the scores of two questions in the computer user questionnaire, have significant negative correlations with comfort. On the other side, the durations of blinks and the scores of three questions in the computer user questionnaire, were significantly correlated with discomfort. CONCLUSION: The warm (3000K) and high intensity (1500 lux) light reduced the visual and cognitive fatigue of the user and therefore improve the comfort of the user during the use of a computer screen.


2017 ◽  
Vol 14 (5) ◽  
pp. 172988141773275 ◽  
Author(s):  
Francisco J Perez-Grau ◽  
Fernando Caballero ◽  
Antidio Viguria ◽  
Anibal Ollero

This article presents an enhanced version of the Monte Carlo localization algorithm, commonly used for robot navigation in indoor environments, which is suitable for aerial robots moving in a three-dimentional environment and makes use of a combination of measurements from an Red,Green,Blue-Depth (RGB-D) sensor, distances to several radio-tags placed in the environment, and an inertial measurement unit. The approach is demonstrated with an unmanned aerial vehicle flying for 10 min indoors and validated with a very precise motion tracking system. The approach has been implemented using the robot operating system framework and works smoothly on a regular i7 computer, leaving plenty of computational capacity for other navigation tasks such as motion planning or control.


2008 ◽  
Author(s):  
Mohammed Goryawala ◽  
Misael Del Valle ◽  
Jiali Wang ◽  
James Byrne ◽  
Juan Franquiz ◽  
...  

2021 ◽  
Vol 11 (14) ◽  
pp. 6390
Author(s):  
Marcin Maciejewski

The paper presents the research of the SteamVR tracker developed for a man-portable air-defence training system. The tests were carried out in laboratory conditions, with the tracker placed on the launcher model along with elements ensuring the faithful reproduction of operational conditions. During the measurements, the static tracker was moved and rotated in a working area. The range of translations and rotations corresponded to the typical requirements of a shooting simulator application. The results containing the registered position and orientation values were plotted on 3D charts which showed the tracker’s operation. Further analyses determined the values of the systematic and random errors for measurements of the SteamVR system operating with a custom-made tracker. The obtained results with random errors of 0.15 mm and 0.008° for position and orientation, respectively, proved the high precision of the measurements.


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