Yaw Rotation Research Articles

Inference of perceptual priors from path dynamics of passive self-motion.

The monitoring of one's own spatial orientation depends on the ability to estimate successive self-motion cues accurately. This process has become to be known as path integration. A feature of sequential cue estimation, in general, is that the history of previously experienced stimuli, or priors, biases perception. Here, we investigate how during angular path integration, the prior imparted by the displacement path dynamics affects the translation of vestibular sensations into perceptual estimates. Subjects received successive whole-body yaw rotations and were instructed to report their position within a virtual scene after each rotation. The overall movement trajectory either followed a parabolic path or was devoid of explicit dynamics. In the latter case, estimates were biased toward the average stimulus prior and were well captured by an optimal Bayesian estimator model fit to the data. However, the use of parabolic paths reduced perceptual uncertainty, and a decrease of the average size of bias and thus the weight of the average stimulus prior were observed over time. The produced estimates were, in fact, better accounted for by a model where a prediction of rotation magnitude is inferred from the underlying path dynamics on each trial. Therefore, when passively displaced, we seem to be able to build, over time, from sequential vestibular measurements an internal model of the vehicle's movement dynamics. Our findings suggest that in ecological conditions, vestibular afference can be internally predicted, even when self-motion is not actively generated by the observer, thereby augmenting both the accuracy and precision of displacement perception.

Three-dimensional effect of pitch, roll, and yaw rotations on maxillomandibular complex movement

ObjectivesThe purpose of this study was to evaluate the 3-dimensional (3D) effect of pitch, roll, and yaw rotations on maxillomandibular complex (MMC) movements in skeletal Class III surgical patients using 3D cone-beam computed tomography (CBCT) data and mathematical calculations. Materials and methodsPreoperative CBCT data of 152 skeletal Class III surgical patients was obtained. The subjects were divided into four groups: group 1, non-extraction with a normal/short face; group 2, non-extraction with a long face; group 3, extraction with a normal/short face; and group 4, extraction with a long face. The maxillary and mandibular landmarks were digitized on the reconstructed 3D models, and the movements of their standardized coordinates by pitch, roll, and yaw rotations were calculated using a transformation matrix. ResultsThe rotations resulted in significantly different amounts of MMC movement among the groups, which generally increased from groups 1 to 4. While roll rotation greatly affected the lateral movement of the menton and the vertical movement of the gonion, yaw rotation primarily affected the lateral and anteroposterior movement of the gonion. Combined pitch and roll rotations were required for unilateral impaction of the maxillary first molar. ConclusionThe 3D surgical treatment objectives (STO) method was valuable for accurate prediction of MMC movements by pitch, roll, and yaw rotations, which are frequently required in orthognathic surgery patients.

Influence of Vehicle Kinematic Components on Chest Injury in Frontal-Offset Impacts

Objective: Frontal crashes in which the vehicle has poor structural engagement, such as small-overlap and oblique crashes, account for a large number of fatalities. These crash modes are characterized by large intrusion and vehicle yaw rotation. Results from previous studies have shown mixed results regarding the importance and effects of these parameters. The aim of this study was to evaluate how vehicle yaw rotation, instrument panel intrusion, and the time history of the pulse angle influence chest injury outcomes.Method: This study was conducted using kinematic boundary conditions derived from physical crash tests, which were applied on a finite element simulation model of a vehicle interior including a finite element human model. By performing simulations with different levels of simplified boundary conditions and comparing the results to a simulation with a full set of boundary conditions, the influence of the simplifications was evaluated. The injury outcome measure compared between the simulations was the expected number of fractured ribs. The 3 simplifications simulated were (1) removal of vehicle yaw rotation, (2) removal of vehicle yaw rotation plus an assumption of a constant pulse angle between the x- and y-acceleration, and (3) removal of instrument panel intrusion.The kinematic boundary conditions were collected from 120 physical tests performed at the Insurance Institute of Highway Safety; 77 were small-overlap tests, and 43 were moderate overlap tests. For each test, the full set of boundary conditions plus the 3 simplifications were simulated. Thus, a total of 480 simulations were performed.Results: The yaw rotation influences occupant interaction with the frontal airbag. For the approximation without this kinematic boundary component, there was an average error in injury outcome of approximately 13% for the moderate overlap cases. Large instrument panel intrusion increases the risk of rib fracture in nearside small-overlap crashes. The mechanism underlying this increased fracture risk is a combination of increased airbag load and a more severe secondary impact to the side structure. Without the intrusion component, the injury risk was underestimated by 8% for the small-overlap crashes.Conclusion: The approximation with least error was version 2; that is, a model assuming a constant pulse angle, including instrument panel intrusion but no vehicle yaw rotation. This approximation simulates a sled test with a buck mounted at an oblique angle. The average error for this approximation was as low as 2–4%.

Human self-motion sensitivity to visual yaw rotations

Human self-motion sensitivity to visual yaw rotations

Expected accuracy of tilt measurements on a novel hexapod-based digital zenith camera system: a Monte-Carlo simulation study

Digital zenith camera systems (DZCS) are dedicated astronomical-geodetic measurement systems for the observation of the direction of the plumb line. A DZCS key component is a pair of tilt meters for the determination of the instrumental tilt with respect to the plumb line. Highest accuracy (i.e., 0.1 arc-seconds or better) is achieved in practice through observation with precision tilt meters in opposite faces (180° instrumental rotation), and application of rigorous tilt reduction models. A novel concept proposes the development of a hexapod (Stewart platform)-based DZCS. However, hexapod-based total rotations are limited to about 30°–60° in azimuth (equivalent to ±15° to ±30° yaw rotation), which raises the question of the impact of the rotation angle between the two faces on the accuracy of the tilt measurement. The goal of the present study is the investigation of the expected accuracy of tilt measurements to be carried out on future hexapod-based DZCS, with special focus placed on the role of the limited rotation angle. A Monte-Carlo simulation study is carried out in order to derive accuracy estimates for the tilt determination as a function of several input parameters, and the results are validated against analytical error propagation. As the main result of the study, limitation of the instrumental rotation to 60° (30°) deteriorates the tilt accuracy by a factor of about 2 (4) compared to a 180° rotation between the faces. Nonetheless, a tilt accuracy at the 0.1 arc-second level is expected when the rotation is at least 45°, and 0.05 arc-second (about 0.25 microradian) accurate tilt meters are deployed. As such, a hexapod-based DZCS can be expected to allow sufficiently accurate determination of the instrumental tilt. This provides supporting evidence for the feasibility of such a novel instrumentation. The outcomes of our study are not only relevant to the field of DZCS, but also to all other types of instruments where the instrumental tilt must be corrected. Examples include electronic theodolites or total stations, gravity meters, and other hexapod-based telescopes.

Illusory self-motion perception evoked by caloric vestibular stimulation in sitting versus supine body positions

The purpose of this study was to determine (i) if a change in the body position that alters the somatosensory afferentation and thus the signal integrated by sensory interaction influences the illusory self-motion perception evoked by cold calorics. If yes, (ii) is the direction of the provoked nystagmus also changed?The vestibular system in 47 healthy subjects was stimulated calorically with 20°C water while in supine and sitting positions but with the head fixed. After each procedure the subjects were asked to describe their self-motion experience, and the provoked nystagmus was analyzed.In 45.7% of these subjects a sensation of yaw rotation was reported while in the sitting position, whereas only 9.6% had this sensation while in the supine position. However, when in the supine position the experience of roll rotation dominated, i.e., 52.1% compared to 5.3% while in the sitting position. Pitch rotation was felt only in the sitting position by 4.3%. There was no such sensation in the supine position. The perception of a full-cycle rotation dominates in the sitting position. In the sitting position 20% of the subjects reported eccentrical head rotation along the circumference of a cone—the top of the cone was located in the neck region. Linear self-motion sensations did not differ in the two positions. The evoked nystagmus in both positions was only horizontal.In conclusion, a change in body position with respect to the gravity vector, while head position is fixed, causes a change in the somatosensory afferentation and modifies the integrated sensory signal by sensory interaction. In turn it influences the self-motion perception evoked by calorics. A change in body position does not affect the direction of nystagmus.

CovGa: A novel descriptor based on symmetry of regions for head pose estimation

This paper proposes a novel method to estimate the head yaw rotation using the symmetry of regions. We argue that the symmetry of 2D regions located in the same horizontal row is more intrinsically relevant to the yaw rotation of head than the symmetry of 1D signals, while at the same time insensitive to the identity of the face. Specifically, the proposed method relies on the effective combination of Gabor filters and covariance descriptors. We first extract the multi-scale and multi-orientation Gabor representations of the input face image, and then use covariance descriptors to compute the symmetry between two regions in terms of Gabor representations under the same scale and orientation. Since the covariance matrix can alleviate the influence caused by rotations and illumination, the proposed method is robust to such variations. In addition, the proposed method is further improved by combining it with a metric learning method named aa KISS MEtric learning (KISSME). Experiments on four challenging databases demonstrated that the proposed method outperformed the state of the art.

Torsional Instability of an Elastic Flat Plate due to Hydrodynamic Loads

AbstractThe present work studies the torsional instability of an elastic structure due to hydrodynamic loads into the water current. The structure applied here is a rectangular flat plate with an elastic axis in its mid-chord length. The elasticity in the structure is provided by torsion spring. The flat plate has only one degree of freedom which is rotation in pure yaw about its axis. Through the free vibration experiments, it is observed that as the current speed exceeds a critical velocity, the flat plate becomes unstable. Two different chord lengths are tested and the instability occurs for a chord base range of Reynolds number, 0.75 × 105< Rec< 1.5 × 105. As a result of the instability, the flat plate begins to yaw about the elastic axis. The hydrodynamic moment acting on the flat plate is modeled by means of the flutter derivatives. As an identification technique to extract flutter derivatives, a curve fitting scheme called General Least-Square (GLS) theory is applied on the results of the free vibration experiments. The results confirm that the structure becomes dynamically unstable due to the hydrodynamic moment applied on it beyond the critical velocity. The super-critical Hopf bifurcation is also discussed in the light of the analysis.

SU-E-T-369: Experience of Using 6D Robotic Couch Top in the Treatment of Intracranial Tumors Utilizing Frameless Stereotactic Radiosurgery (SRS) Technique

Purpose: To investigate the extent and necessity of 6 DOF corrections for intracranial frameless Stereotactic Radiosurgery Methods: Civco Protura 6D robotic couch top was fitted to the Novalis TX in 2012. The couch enables ± 3 ° rotations in pitch, roll and yaw, ±50 mm in lateral and longitudinal shifts and ±25 mm in vertical shifts. Patient sets up using the room laser; then two orthogonal kV images are taken for confirmation. A CBCT is acquired and registered to the planning CT using two independent systems. The calculated rotational and translational shifts are applied. A second CBCT is acquired to assess the residual translational and rotational errors. The treatment will be carried out if residual rotational shifts are ≤ 0.3 degrees. We treated 113 patients utilizing 6D couch to align a total of 160 targets. Some of the targets were fractionated, with total alignments of 252. Geometrical analysis is performed to assess the system's accuracy and extent of shifts. Results: After the planar kV images alignment, a CBCT was acquired and registered to the planning CT, the average required rotational shifts were (yaw=1.03 °± 0.8, roll=1.16°± 0.9 and Pitch= 0.9°± 0.7). A second CBCT was taken to verify the match and the previous shifts, the residual rotational errors on average were 0.37°± 0.6, 0.27°± 0.28 and 0.24°± 0.29 in the yaw, roll, and pitch directions, respectively. The translational residual shifts (mm) were 0.68 ± 0.57, 0.68 ± 0.57, 0.68 ± 0.57 in lateral, vertical, and longitudinal directions, respectively. Conclusion: The 6D couch is capable of aligning targets with an accuracy of ≤ 0.4 ° in any rotational direction and ≤ 0.7 mm in any translational directions, and not applying the rotational corrections could lead to compromised target dose coverage and may lead to excessive dose to OARs.

Retroreflector for GRACE follow-on: Vertex vs. point of minimal coupling.

The GRACE Follow-On mission will monitor fluctuations in Earth's geoid using, for the first time, a Laser Ranging Interferometer to measure intersatellite distance changes. We have investigated the coupling between spacecraft rotation and the intersatellite range measurement that is incurred due to manufacturing and assembly tolerances of the Triple Mirror Assembly (TMA), a precision retroreflector to ensure alignment between in- and outgoing laser beams. The three TMA mirror planes intersect in a virtual vertex to which satellite displacements are referenced. TMA manufacturing tolerances degrade this ideal vertex, however, a Point of Minimal Coupling (PMC) between spacecraft rotation and displacement exists. This paper presents the experimental location of the PMC under pitch and yaw rotations for a prototype TMA. Rotations are performed using a hexapod, while displacements are monitored with heterodyne laser interferometry to verify the PMC position. Additionally, the vertex of the three TMA mirror planes is measured using a Coordinate Measuring Machine and compared to the PMC position. In the pitch and yaw axes, the biggest deviation between TMA vertex and PMC was 50 ± 64 μm. Thus, within the measurement uncertainties, no difference between TMA vertex and PMC could be observed. This is a key piece of information for integration of the TMA into the spacecraft: It is sufficient to use the readily-available TMA vertex location to ensure minimal rotation-to-displacement coupling during the mission.

Motion Perception in Patients with Idiopathic Bilateral Vestibular Hypofunction

We measured vestibular perceptual thresholds in patients with idiopathic bilateral vestibulopathy to assess the distribution of peripheral vestibular damage in this disorder. Thresholds were measured with standard psychometric techniques in 4 patients and compared with thresholds in normal subjects and patients with completely absent peripheral vestibular function. Motion paradigms included yaw rotation (testing the lateral canals), interaural translation (testing the utricles), superior-inferior translation (testing the saccules), and roll tilt (testing the vertical semicircular canals and the otolith organs). We found that perceptual thresholds were abnormally elevated in the patients with idiopathic bilateral vestibulopathy for yaw rotation at all frequencies and for interaural translation at only the lower frequencies. Thresholds were normal for the other 2 motion paradigms. The results demonstrate that the distribution of vestibular dysfunction in this disorder is not uniform but, rather, can affect lateral canal and utricular thresholds while relatively sparing vertical canal and saccular function.

Phenomenological model for torsional galloping of an elastic flat plate due to hydrodynamic loads

This study investigates the torsional galloping phenomenon, an instability type flow-induced oscillation, in an elastic structure due to hydrodynamic loads into the water current. The structure applied here is a rectangular flat plate with an elastic axis in its mid-chord length. The elasticity is provided by torsion spring. The flat plate has only one degree of freedom which is rotation in pure yaw about its axis. It is observed that as the current speed is higher than a critical velocity, the flat plate becomes unstable. The instability leads to torsional galloping occurrence, as a result of which the flat plate begins to yaw about the elastic axis. By testing two different chord lengths each with several torsion spring rates, the flat plate behavior is investigated and three different responses are recognized. Then, a phenomenological model is developed with the original kernel in the form of the van der Pol-Duffing equation. The model explains these three responses observed experimentally.

Human Yaw Rotation Aftereffects with Brief Duration Rotations Are Inconsistent with Velocity Storage

In many sensory systems, perception of stimuli is influenced by previous stimulus exposure such that subsequent stimuli may be perceived as more neutral. This phenomenon is known as an aftereffect and has been studied for vision, audition, and some vestibular stimuli including roll and translation. Previous data on yaw rotation perception has focused on low-frequency stimuli on the order of a minute which may not be directly applicable to frequencies during ambulation. The aim of the current study is to look at the influence of yaw rotation on subsequent perception near 1 Hz, the predominant frequency of yaw rotation during human ambulation. Humans were rotated with 12 ° whole body adapting stimulus over 1 or 1.5 s. After an interstimulus interval (ISI) of 0.5, 1.0, 1.5, or 3 s, a test stimulus the same duration as the adapting stimulus was presented, and subjects pushed a button to identify the direction of the test stimulus as right or left. The direction and magnitude of the test stimulus was adjusted based on prior responses to find the stimulus at which no rotation was perceived. Experiments were conducted both in darkness and with a visual fixation point. The presence of a fixation point did not influence the aftereffect which was largest at 0.5 s with an average size of 0.78 ± 0.18°/s (mean ± SE). The aftereffect diminished with a time constant of ~1 s. Thresholds were elevated after the adapting stimulus and also decreased with a time constant of ~1 s. These findings demonstrate that short adapting stimuli can induce significant aftereffects in yaw rotation perception and that these aftereffects are independent from the previously described velocity storage.

Towards Lane-Keeping Electronic Stability Control for Road-Vehicles

The emerging new idea of lane-keeping electronic stability control is investigated. In a critical situation, such as entering a road curve at excessive speed, the optimal behavior may differ from the behavior of traditional ESC, for example, by prioritizing braking over steering response. The important question that naturally arises is if this has a significant effect on safety. The main contribution here is to give a method for some first quantitative measures of this. It is based on optimal control, applied to a double-track chassis model with wheel dynamics and high-fidelity tire-force modeling. The severity of accidents grows with the square of the kinetic energy for high velocities, so using kinetic energy as a measure will at least not overestimate the usefulness of the new safety system principle. The main result is that the safety gain is significant compared to traditional approaches based on yaw rotation, for several situations and different road-condition parameters.

3P2-E03 水中上肢リハビリテーション補助用ロボットの開発 : 前腕回内/外運動リハビリテーション装置の開発(リハビリテーションロボティクス・メカトロニクス)

The aim of this study was to develop the novel underwater robotic device to achieve forearm abduction/adduction rehabilitation with master-slave system. The developed system could execute the 5-degree-of-freedom motion (anterior-posterior and vertical motion, and pitch, yaw, and roll rotation). We evaluated this system and the results showed enough functional capability for underwater upper limb rehabilitation, especially in the abduction/adduction rotation in forearm. Further studies are needed to achieve this system and to evaluate the efficacies regaining the for hemiparetic patients.

1B25 Examination of Maneuverability of an Inverted-pendulum Vehicle in Terms of Handle Operation(The 12th International Conference on Motion and Vibration Control)

We experimentally investigated the maneuverability and comfort of an inverted-pendulum vehicle when operated with handle roll rotation and handle yaw rotation. Our experimental vehicle can switch between handle modes and is equipped with a Bluetooth communication function for measurement of the state of the vehicle. We thus investigated the two handle operations at high, intermediate and low gains. The experimental course was a slalom course with two cones placed at an interval of 1.8 m. The research participants made one round trip. The trajectory of the vehicle was measured by a three-dimensional motion analysis device called VICON. Maneuverability for the two types of handle operartios and for various control gains was determined from data of the trajectory of the vehicle, revolutions of the wheel, the steering angle, and a questionnaire.

AN ADAPTIVE SCHEME FOR IMAGE-BASED VISUAL SERVOING OF AN UNDERACTUATED UAV

An image-based visual servoing (IBVS) method is proposed for controlling the 3D translational motion and the yaw rotation of a quadrotor. The dynamic model of this unmanned aerial vehicle (UAV) is considered at the design stage to account for its underactuation. In contrast with previous IBVS methods for underactuated UAVs, which used spherical image moments as visual features, the proposed controller makes use of appropriately defined perspective moments. As a consequence, we gain a clear improvement in performance, as satisfactory trajectories are obtained in both image and Cartesian space. In addition, an adaptation mechanism is included in the controller to achieve robust performance in spite of uncertainties related to the depth of the image features and to the dynamics of the robot. Simulation results in both nominal and perturbed conditions are presented to validate the proposed method.

Neural Representation of Orientation Relative to Gravity in the Macaque Cerebellum

A fundamental challenge for maintaining spatial orientation and interacting with the world is knowledge of our orientation relative to gravity, i.e., head tilt. Sensing gravity is complicated because of Einstein's equivalence principle, in which gravitational and translational accelerations are physically indistinguishable. Theory has proposed that this ambiguity is solved by tracking head tilt through multisensory integration. Here we identify a group of Purkinje cells in the caudal cerebellar vermis with responses that reflect an estimate of head tilt. These tilt-selective cells are complementary to translation-selective Purkinje cells, such that their population activities sum to the net gravitoinertial acceleration encoded by the otolith organs, as predicted by theory. These findings reflect the remarkable ability of the cerebellum for neural computation and provide quantitative evidence for a neural representation of gravity, whose calculation relies on long-postulated theoretical concepts such as internal models and Bayesian priors.

Neural Basis of Stimulus-Angle-Dependent Motor Control of Wind-Elicited Walking Behavior in the Cricket Gryllus bimaculatus

Crickets exhibit oriented walking behavior in response to air-current stimuli. Because crickets move in the opposite direction from the stimulus source, this behavior is considered to represent ‘escape behavior’ from an approaching predator. However, details of the stimulus-angle-dependent control of locomotion during the immediate phase, and the neural basis underlying the directional motor control of this behavior remain unclear. In this study, we used a spherical-treadmill system to measure locomotory parameters including trajectory, turn angle and velocity during the immediate phase of responses to air-puff stimuli applied from various angles. Both walking direction and turn angle were correlated with stimulus angle, but their relationships followed different rules. A shorter stimulus also induced directionally-controlled walking, but reduced the yaw rotation in stimulus-angle-dependent turning. These results suggest that neural control of the turn angle requires different sensory information than that required for oriented walking. Hemi-severance of the ventral nerve cords containing descending axons from the cephalic to the prothoracic ganglion abolished stimulus-angle-dependent control, indicating that this control required descending signals from the brain. Furthermore, we selectively ablated identified ascending giant interneurons (GIs) in vivo to examine their functional roles in wind-elicited walking. Ablation of GI8-1 diminished control of the turn angle and decreased walking distance in the initial response. Meanwhile, GI9-1b ablation had no discernible effect on stimulus-angle-dependent control or walking distance, but delayed the reaction time. These results suggest that the ascending signals conveyed by GI8-1 are required for turn-angle control and maintenance of walking behavior, and that GI9-1b is responsible for rapid initiation of walking. It is possible that individual types of GIs separately supply the sensory signals required to control wind-elicited walking.

Robust vision-based control of an underactuated flying robot tracking a moving target

In this paper a robust image-based visual servo (IBVS) scheme is presented for a quadrotor tracking a moving target. The objective is to consider the full dynamics of the system to design vision-based controllers for the translational motion and the yaw rotation of this unmanned aerial vehicle. Passivity properties of the dynamics of the image features obtained from perspective image moments in a virtual image plane are used to solve the problem of designing full dynamic IBVS controllers for these robots. Nonlinear robust controllers are designed to deal with uncertainties in the dynamics of the image features and also uncertainties in the dynamics of the robot. The controllers need neither 3D information of the target model nor yaw information of the robot. Stability analysis guarantees that the states of the system are uniformly ultimately bounded. Simulation results are presented to validate the designed controllers.