Degrees Of Freedom Motion Platform Research Articles

Vestibular perceptual learning improves self-motion perception, posture, and gait in older adults

Vestibular motion perception declines with age, increasing the risk of falling substantially. We performed a two-week perceptual learning intervention using a self-motion direction discrimination task (2800 training trials per person) on a 6 degrees of freedom motion platform in healthy older adults (n = 40, aged 70–88 yr). Linear inter-aural and angular roll tilt vestibular thresholds improved with training (95% credible interval for pre/post difference), suggesting altered sensitivity post-training. Moreover, improved perceptual abilities transfer to actual posture (reduced sway) and gait parameters. Passive self-motion discrimination training provides a new and promising way to counteract age-related sensory decline. It can reduce the risk of falling, and thereby maintain individual autonomy and quality of life.

Numerical and Experimental Studies of Shallow‐Water Sloshing Motions in a Prismatic Tank

Shallow‐water sloshing behavior within a prismatic tank has been analyzed utilizing a model of Boussinesq‐type equations. The Boussinesq‐type equations are calculated by the five‐points finite difference method and extrapolating boundary technique are adopted for simulating the runup phenomena around the inclined bottom. The numerical grid points are divided into the wet region which are evaluated by the Boussinesq‐type equations and the dry region which are obtained from extrapolating boundary technique. The experimental studies of sloshing motions in the prismatic tank were carried out based on the six degrees of freedom motion platform. And the free surface profiles on the inclined bottom were compared between the numerical and experimental results. In the vicinity of the lowest natural frequency, the numerical model presents very good performance on nonbreaking sloshing motions. Based on the numerical Boussinesq‐type model, the frequency response of sloshing motion in prismatic tanks with different inclined bottoms is compared and the transformation from hard-spring effect to soft-spring effect can be found. With the angle of inclined bottom decreased the main wave pattern in the prismatic tank change from nonlinear traveling waves to standing waves.

Modelling and analysis for the dynamic behavior of 6-DOF motion platform used for simulating aerospace mechanical environment

As high carrying capacity, high frequency response and high precision control performance are presented, the 6 degree of freedom (DOF) motion platform is chosen as the aerospace device to implement mechanical environment simulation experiment on the ground. In this paper, a dynamic model of the 6 DOF motion platform is firstly developed based on the Newton-Euler method. Then the attitude determination and the driving force are analyzed by solving the dynamic equations. Furthermore, a parametric modelling method for the 6 DOF motion platform is proposed and applied to obtain the expansion amounts and the driving forces of the 6 hydraulic rods in the motion platform by adopting the Adams software. Results show a good agreement with the computation results of the theory dynamic model, which demonstratesthe validity of the proposed modelling method for analysis of the dynamic behavior of the 6-DOF motion platform.

Design of 6-DOF Tomato Picking Lifting Platform

The tomato picking lifting platform is the carrier for the installation of the picking manipulator, which directly affects the operating range, speed, and picking effect of the picking manipulator. Based on the six degree of freedom motion platform, this paper designs a tomato lifting platform with automatic lifting and automatic leveling functions, which can accurately dock at the designated height to complete the picking operation, and verifies the validity of its parameters and the rationality of the operation movement. First, we analyzed the tomato planting mode and growth characteristics of greenhouse; determined the predetermined trajectory, mechanism travel, and motion form of the lifting platform to complete the lifting process during tomato picking; and determined the basic design parameters of the platform; Secondly, we used SolidWorks to build the three-dimensional model of the lifting platform, and imported it into ADAMS. We used the driving function to complete the dynamic simulation of the virtual prototype of the lifting platform, and obtained the force curve of the electric cylinder and hinge. We analyzed the force on the electric cylinder and hinge of the lifting platform to determine the rationality of the device design. Finally, according to the design requirements and simulation data, we made the prototype of the lifting platform, constructed the motion control system, and carried out relevant experiments. The experimental results show that the maximum rotation angle around the x, y, and z axis is ±10°, the maximum lifting distance is 15 cm, and the maximum load is 50 kg; meanwhile, the average time for the system to reach steady state is 0.309 s, the in-tilt error increases with the increase in biaxial tilt angle, with the maximum error of 1.09°, and the maximum mean square root error of 0.119°, which can meet the automatic operation requirements of the tomato picking manipulator.

Design and experimental study of plasma device for accurate contour scanning

Herein, a plasma device with precise and controllable sterilization range was designed. It comprises three parts: mechanical motion, visual, and plasma parts. The mechanical motion part comprises a three degree of freedom motion platform and a camera module. The overall unit size is 408 mm × 356 mm × 300 mm, and the effective movement area is 100 mm × 100 mm × 45 mm. For the visual part, the OpenMV module, an onboard STM32f767vit6 chip, and an ov5640 sensor are used for programming. After shooting, the image is set to a gray image matrix of 180 × 180 pixels. The plasma device is a single electrode helium plasma, and the produced active substances such as H2O2 and NO3− decrease with increasing moving speed of the moving platform. Through machine learning and control, the device realizes the accurate scanning of closed graphics with an edge thickness greater than 0.5 mm and the accurate sterilization of graphics with different shapes and areas.

Nonlinear identification and optimal feedforward friction compensation for a motion platform

In this study, we present a method of nonlinear identification and optimal feedforward friction compensation for an industrial single degree of freedom motion platform. The platform has precise reference tracking requirements while suffering from nonlinear dynamic effects, such as friction and backlash in the driveline. To eliminate nonlinear dynamic effects and achieve precise reference tracking, we first identified the nonlinear dynamics of the platform using Higher Order Sinusoidal Input Describing Function (HOSIDF) based system identification. Next, we present optimal feedforward compensation design to improve reference tracking performance. We modeled the friction using the Stribeck model and identified its parameters through a procedure including a special reference signal and the Nelder–Mead algorithm. Our results show that the RMS trajectory tracking error decreased from 0.0431 deg/s to 0.0117 deg/s when the proposed nonlinear identification and friction compensation method is utilized.

Open-source five degree of freedom motion platform for investigating fish-robot interaction.

This paper presents the design, construction, operation, and validation of a robotic gantry platform specifically designed for studying fish-robot interaction. The platform has five degrees of freedom to manipulate the three-dimensional position, yaw angle, and the pitch of a lure. Additionally, it has a four-conductor slip ring that allows power and data to be transmitted to the lure for the operation of fins and other actuators that increase realism or act as stimuli to focal fish during an ethorobotic experiment. The design is open-source, low-cost, and includes purpose-built electronics, software, and hardware to make it extensible and customizable for a number of applications with varying requirements.

An inverse kinematic analysis modeling on a 6-PSS compliant parallel platform for optoelectronic packaging

Multiple degree of freedom motion platform is always one of the important components in optoelectronic packaging systems, its characteristics have a vital impact on the performances of optoelectronic packaging. This paper presents a 6-Prismatic-Spherical-Spherical compliant parallel platform for optoelectronic packaging. This platform is a kind of parallel layout structure, which uses the piezoelectric motors as active joints and the large-stroke flexure hinges are employed as passive joints. An inverse kinematic modeling based on elastokinematic analysis is analyzed and deduced. The elastokinematic analysis considers the elastic deformation of the large-stroke flexure hinges in movement process, and improves the positioning accuracy of the compliant parallel platform in applications. The finite element analysis model and the prototype of the compliant parallel platform are developed, and the validity of the proposed method is finally verified. This paper provides a theoretical reference and experimental data for the inverse kinematic analysis of six degrees of freedom motion compliant parallel platforms with large-stroke flexure hinges.

Experimental studies of suppressing effectiveness on sloshing with two perforated floating plates

In the present paper, model tests of suppressing sloshing fitted with two perforated floating plates are carried out. The study involves identification of system performance such as the suppression and the solidity ratio. Three different solidity ratios of perforated plates have been tried out as potential positive slosh damping devices. A series of painstaking experiments have been conducted in a rigid rectangular tank on six degrees of freedom motion platform under roll harmonic excitation. Comparison of the clean tank shows that the three types of perforated plates are all effective on damping the run-up and impact pressure along the bulkhead. The parametric study indicates that the perforated plate with the median solidity ratio is the most optimal one in suppressing sloshing among three configurations.

Vestibular-Auditory Interactions: Assessing the Influence of Passive Self-Motion on Auditory Localisation

Event Abstract Back to Event Vestibular-Auditory Interactions: Assessing the Influence of Passive Self-Motion on Auditory Localisation Luzia Grabherr1*, Vanda Lory2 and Fred Mast2, 3 1 University of South Australia, Sansom Institute for Health Research, Australia 2 University of Bern, Department of Psychology, Switzerland 3 University of Bern, Center for Cognition, Learning and Memory, Switzerland Background: The vestibular system serves as an important source of information for the perception of self-motion. Although it is well known that there is a close interrelation between vestibular and visual information processing (e.g. vestibulo-ocular-reflex), comparatively little attention has been paid to the study on crossmodal attention between the vestibular system and other modalities. Methods: We assessed the influence of passive self-motion on auditory information processing with a spatial cueing paradigm. Using a 6 degree of freedom motion platform, we presented right- and leftward motion cues, which were followed by unilaterally presented tones. Participants were blindfolded and wore headphones. Stimulus onset asynchronies (SOA) between self-motion and tone presentation varied from 250ms to 1500ms. Thus, the experiment consisted of congruent trials in which the motion direction was the same as the following tone presentation side (e.g. leftward self-motion followed by left ear tone presentation) and incongruent trials (e.g. leftward self-motion followed by right ear tone presentation). In total, 23 participants were tested and their task was to evaluate the tone presentation side (left or right). We hypothesized that response times are facilitated in congruent trials and at shorter SOAs. Results: We found a significant main effect of "SOA" (p < .001). Response times were shortest at 750ms SOA. Critically, however, there was no significant main effect of "congruency" and no significant interaction of "congruency x SOA". Conclusions: From these results we conclude, that self-motion can promote auditory attention but disregarding the direction of the cue. Acknowledgements: This research was supported by the Swiss National Science Foundation (postdoctoral fellowship awarded to L.G., Sinergia and ProDoc fellowship awarded to F.M.). Keywords: Attention, Perception, auditory, vestibular, spatial-cueing, own-body motion Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Sensation and Perception Citation: Grabherr L, Lory V and Mast F (2015). Vestibular-Auditory Interactions: Assessing the Influence of Passive Self-Motion on Auditory Localisation. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00123 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Dr. Luzia Grabherr, University of South Australia, Sansom Institute for Health Research, Adelaide, Australia, luziagrabherr@gmx.ch Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Luzia Grabherr Vanda Lory Fred Mast Google Luzia Grabherr Vanda Lory Fred Mast Google Scholar Luzia Grabherr Vanda Lory Fred Mast PubMed Luzia Grabherr Vanda Lory Fred Mast Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Modelling and design of an augmented reality differential drive mobility aid in an enabled environment

In this paper the authors discuss the modelling and design of an augmented reality platform for disabled wheeled mobility studies. This design consists of a virtual environment with two degrees of freedom motion platform and integrated ground contact force feedback. Differential drive mobility users continue to be in touch with reality on their own mobility aid while interacting with virtual objects. The major domain related to the differential drive mobility of the disabled members of society which coincides with the use of manual wheelchairs, electric wheelchairs and mobility scooters. In order to account for environmental and dynamic effects, the wheeled mobility user needs to map the intended trajectory into the virtual world. Motion and inertia force feedback produced on the augmented simulator give the users a haptic sensory stimulus input regarding spatial movement and ground contact forces. The main objective is to model and design an augmented reality platform with real world kinematic and dynamic properties to place a wheeled mobility user closer to real world encounters. The use of the designed augmented reality platform will be beneficial to disabled wheeled mobility users in need of occupational therapist training and evaluation.

Dynamic Characteristics Analysis of Simulator Six-DOF Platform

Six degrees of freedom motion platform is an important part of the flight simulator. To study the dynamic characteristics of the simulator, the paper carried a six degree of freedom motion platform dynamics analysis, and proposed fuzzy PID control strategy, and through the ADAMS software to establish a simulation model of six degrees of freedom motion platform, simulation results show that the use of strategy has good control effect for the simulator is designed to provide some reference.

Immersion Suit Donning in Dynamic Environments: Implications for Design, Construction & Use

Marine abandonment immersion suits are a vital piece of safety equipment intended to protect individuals from exposure to harsh environmental elements. The operational effectiveness of a well maintained and fitted suit depends on the ability of a user to correctly don a suit system. Thirty‐two participants performed immersion suit donning trials in six experimental conditions. Dynamic, pre‐abandonment marine emergency scenarios were simulated using a six degrees of freedom motion platform and varying environmental lighting levels. This article details user‐suit interaction challenges encountered throughout immersion suit donning tasks and examines their connection to safety and survival in marine emergencies. Analysis of user‐suit functionality during the donning process is critical for identifying current deficiencies in order to develop future design solutions, training methodologies and ultimately improve users’ practical competencies.

An Approach Toward Visual Autonomous Ship Board Landing of a VTOL UAV

We present the design and implementation of a vision based autonomous landing algorithm using a downward looking camera. To demonstrate the efficacy of our algorithms we emulate the dynamics of the ship-deck, for various sea states and different ships using a six degrees of freedom motion platform. We then present the design and implementation of our robust computer vision system to measure the pose of the shipdeck with respect to the vehicle. A Kalman filter is used in conjunction with our vision system to ensure the robustness of the estimates. We demonstrate the accuracy and robustness of our system to occlusions, variation in intensity, etc. using our testbed.

A Comparison of Platform Motion Waveforms During Constrained and Unconstrained Standing in Moving Environments

OCCUPATIONAL APPLICATIONS Using a principal component waveform analysis technique to examine the platform kinematics during motion-induced interruptions and motion-induced corrections found that these events significantly differ in perturbation magnitude at the time of stepping initiation. These results suggest that differences between the motion-induced interruptions and motion-induced corrections are more than just theoretical, and therefore, when examining these events in offshore environments, they cannot be considered one and the same. Since these change-in-support reactions may be an alternative instead of a last resource response, they may also not be a clear indicator of ship operability. Therefore, when evaluating the risks associated with performing tasks in moving environments, the resultant effects of the change-in-support reactions, such as motion-induced interruptions or motion-induced corrections and their potential effect on injury mechanisms, must also considered. TECHNICAL ABSTRACT Background: Postural response research suggests that change-in-support reactions involving the movement of feet may occur long before the physics-based stability limits have been reached. As such, the current definition of a motion-induced interruption used to describe change-in-support reactions in offshore environments may not be valid, and the alternative motion-induced correction definition may be more appropriate. However, differences between motion-induced interruptions and motion-induced corrections are currently unknown. Purpose: The purpose of this study was to determine the differences in platform motion waveforms between motion-induced interruption and motion-induced correction occurrences when standing on a 6 degree of freedom motion platform. Methods: Twenty participants (ten male, ten female) with little or no experience working in marine environments performed a constrained and unconstrained stationary standing task while being exposed to a continuous multi-directional wave-like perturbation. The constrained standing task was representative of motion-induced interruptions, while the unconstrained standing task was representative of motion-induced corrections. Principal component analysis was incorporated, permitting the preservation of temporal characteristics unique to each motion curve in the analysis. Students’ t-tests were performed on the derived significant principal component scores to determine if these components were statistically significantly different between constrained and unconstrained standing. Results: Analysis of pitch and roll axes suggest that most of the variability of platform motions between motion-induced interruptions and motion-induced corrections can be described by two principal components. The first component, accounting for 80%–90% of all variability, was a magnitude modifier and suggests that there are quantifiable differences in the platform motions that cause motion-induced interruptions and motion-induced corrections. Conclusions: The results of this research suggest that it is likely that the motions to induce these events are distinctly different; therefore, motion-induced interruptions and motion-induced corrections should be considered as different events when examining the human response to wave-induced ship motions and ship operability.

3407 個人適合型運転支援のためのドライバ運転挙動解析(OS7 人間・機械システム,ヒューマンインターフェース)

To make the active safety devices easy to accept the driver, it becomes to be important to develop the driver support system suiting to individual driver characteristics. The database of the characteristics is necessary to achieve such a system. This paper describes the analysis of driver behavior to extract the individual driving characteristics. The data of driver behavior is measured using a driving simulator. The simulator is composed of the 6 degrees of freedom motion platform and the translatable motion device that moves the platform longitudinally. In the cockpit on the platform, a driver's seat is put and the front view is reflected on 3 flat screens 1.4m away from the driver. The driving tasks in this study were supposed to contain the various traffic situations; lane changing, stopping and starting at intersection, and making to look aside such as seeing signboard. In case of looking aside, it was derived that the deviation from the lane center became larger than usual driving. The large part of the deviation was caused at passing near the signboard. It became also clarified that the amount of the deviation was quite different individually. Based on these results of analysis, the database to describe the individual driver behavior characteristics has been constructed. These data becomes useful to decide the adapting situation and the timing of driver support system.