Endpoint Position Research Articles

Definition of service angle of android’s robot hand by method of small movements of gripper’s axis synthesis by speed vector

The paper presents a generalized method for determining the service solid angle based on the assigned gripper axis orientation with a stationary grip center. Motion synthesis in this work is carried out in the vector of velocities. As an example, a solid angle of the android robot arm is determined, this angle being formed by the longitudinal axis of a gripper. The nature of the method is based on the study of sets of configuration positions, defining the end point positions of the unit radius sphere sweep, which specifies the service solid angle. From this the spherical curve specifying the shape of the desired solid angle was determined. The results of the research can be used in the development of control systems of autonomous android robots.

Forward-backward multiplicity fluctuations in ultrarelativistic nuclear collisions with wounded quarks and fluctuating strings

We analyze a generic model where wounded quarks are amended with strings in which both end-point positions fluctuate in spatial rapidity. With the assumption that the strings emit particles independently of one another and with a uniform distribution in rapidity, we are able to analyze the model semi-analytically, which allows for its detailed understanding. Using as a constraint the one-body string emission functions obtained from the experimental data for collisions at $\sqrt{s_{NN}}=200$ GeV, we explore the two-body correlations for various scenarios of string fluctuations. We find that the popular measures used to quantify the longitudinal fluctuations are limited with upper and lower bounds and assume close values for the most likely models of the end-point distributions, which may explain why various approaches yield here very similar results.

Application of Numerical Model of Continuous Cast Bloom Crystallization to Improve the Efficiency of Mechanical Soft Reduction Technology

The paper presents the results of the analysis of thermal state of continuous cast bloom on the stage of incomplete crystallization in the area of possible places of application of technology of Mechanical Soft Reduction (MSR), received during simulation on mathematical model, which was implemented in the software package using the finite element method. For the conditions of continuous cast bloom with a cross section of 360-400 mm, we studied the characteristics of temperature change over the cross section of the bloom, the growth dynamics of the solid shell, the number of the solidified component, and the end point position of solidification depending on the technological parameters for continuous casting of A516, 5140 1070 and AISI steel brands. The obtained data on the thickness of the crystallized shell of continuous cast bloom and the amount of solid phase depending on the casting speed and steel grade allowed us to conclude about the possible place of installation of the MSR unit. The results of mathematical simulation can be transferred in a digital form to the strength model of deformation of continuous cast bloom at the stage of incomplete crystallization.

Lane Endpoint Detection and Position Accuracy Evaluation for Sensor Fusion-Based Vehicle Localization on Highways.

Landmark-based vehicle localization is a key component of both autonomous driving and advanced driver assistance systems (ADAS). Previously used landmarks in highways such as lane markings lack information on longitudinal positions. To address this problem, lane endpoints can be used as landmarks. This paper proposes two essential components when using lane endpoints as landmarks: lane endpoint detection and its accuracy evaluation. First, it proposes a method to efficiently detect lane endpoints using a monocular forward-looking camera, which is the most widely installed perception sensor. Lane endpoints are detected with a small amount of computation based on the following steps: lane detection, lane endpoint candidate generation, and lane endpoint candidate verification. Second, it proposes a method to reliably measure the position accuracy of the lane endpoints detected from images taken while the camera is moving at high speed. A camera is installed with a mobile mapping system (MMS) in a vehicle, and the position accuracy of the lane endpoints detected by the camera is measured by comparing their positions with ground truths obtained by the MMS. In the experiment, the proposed methods were evaluated and compared with previous methods based on a dataset acquired while driving on 80 km of highway in both daytime and nighttime.

Superstatistics and the effective QCD phase diagram

We study the effect of a partially thermalized scenario for chiral symmetry restoration at finite temperature and quark chemical potential, and in particular for the position of the critical end point in an effective description of the QCD phase diagram. We show that these effects produce the critical end point to be displaced towards larger values of temperature and lower values of the quark chemical potential as compared to the case when the system can be regarded as completely thermalized. We conclude that these effects may be important for relativistic heavy ion collisions where the number of subsystems making the whole interaction volume can be linked to the finite number of participants in the reaction.

Finite volume effects on the chiral phase transition from Dyson–Schwinger equations of QCD

Within the framework of Dyson–Schwinger equations of QCD, we study the finite volume effects on the chiral phase transition, especially the influence on the position of the possible pseudo-critical end point (pCEP). The results show that in the chiral limit case (the current quark mass m=0), the absolute value of quark condensate decreases for smaller volumes, and more interestingly, so does the pseudo-critical temperature Tc(μ=0), which is in agreement with the Polyakov Nambu–Jona-Lasinio model result and opposite to the Polyakov linear sigma model prediction. These conclusions hold for m>0 case in our calculations. Moreover, the results of pCEP as a function of different volumes show that T of pCEP also decreases for smaller volumes, but μ of pCEP will increase, which are qualitatively more close to Polyakov linear sigma model results. For our model setup, results for systems with a size larger than (5 fm)3 closely approximate those from infinite volume, but if the volume is smaller, the corrections are non-negligible, even significantly affect signatures of the results from an infinite system. There also exists some possibility that, if the system size is too small, the whole phase transition would be crossover, which means no pCEP exists at all. It is no doubt that, finite volume effects deserve further researches.

EMG Patterns of the Elbow- and Shoulder-Operating Muscles in Slow Parafrontal Upper Limb Movements under Isotonic Loading

Averaged EMGs were recorded from the elbow- and shoulder-operating muscles in 10 adult men during parafrontal slow test movements of the hand performed within the horizontal plane. The movements between the left and right end-point positions were carried out with a constant 4 cm/sec velocity in both directions consequently; two identical isotonic loads (10.2 N) were applied to the hand along the rightward and leftward movement traces (Fr and Fl) with respect to the subject’s body. The elbow and shoulder flexors demonstrated a synergic unification, reacting predominantly to the Fr loads; a similar synergy was manifested by the extensors of both joints in their reactions to the Fl loads. Under the action of the corresponding loads, EMGs of both flexor and extensor muscle groups showed strong hysteresis (counterclockwise and clockwise loops, respectively). The muscles acting as agonists for a given direction of loading (flexors for the Fr loads, extensors for the Fl loads) participated also in a co-contraction mode as antagonists in the movements fulfilled under oppositely directed loads; the direction of hysteresis loops was reversed in this case, and their amplitude decreased. The obtained results allow us to conclude that hysteresis properties of muscle contraction and the related characteristics of signal transmission in the motor control system lead to strong hysteresis-associated modifications of central commands coming to the muscles in various movement tasks.

An enhanced method to control the residual vibrations of a single-link flexible glass fabric reinforced epoxy-glass composite manipulator

Lighter manipulators are used due to reducing power consumption and reaching higher speeds for applications. Composite manipulators can be more desirable for this purpose because they are light weight and have high strength. As it is well known that using flexible manipulators causes high amplitude vibrations and this affects the accuracy of end-point positioning. In this study, a single-link flexible glass fabric reinforced epoxy-glass composite manipulator is analyzed in ANSYS and the residual vibrations are controlled with a new method. The finite element vibration analysis is performed and an experimental system is introduced to verify simulation results. [0/90] lay-up and two different velocity profiles are studied for different case studies. An exponential-harmonic velocity excitation is applied after the end of the trapezoidal velocity profile to control the residual vibrations. It is known that the vibration amplitudes of a system decrease when the system is excited at higher frequency than the natural frequencies. The effect of the amplitude, frequency, the duration of the application and the exponential decay factor on the suppression of the residual vibration are analyzed. Both simulation and experimental analyses are performed and the results are in good agreement. It is concluded that the residual vibration amplitudes of the flexible composite manipulator are suppressed with the proposed method up to 99% for all velocity inputs.

Stable impact and contact force control by UAV for inspection of floor slab of bridge

ABSTRACTThis paper describes the contact force control on an unmanned aerial vehicle (UAV) developed to inspect the floor slabs of bridges. Our UAV is equipped with a three degree-of-freedom manipulator on top of the UAV body. To control the UAV for stable contact with the slab surface, the impact force should be considered. The impact force is modeled based on Hertzian contact stress. The control strategy of the UAV is cascade control separated into attitude control and position-force control. The attitude, position and force feedback are PID control. The force feedback is integrated into the position feedback seamlessly, and the output of the force feedback is added to the desired end-point position of the manipulator. This paper focuses on contact of the UAV and the floor slab. Therefore, the UAV is modeled considering the impact force in the vertical direction. The control method in the vertical direction is described, and then the altitude control and the contact force control are assessed. The altitude of the UAV was controlled with a 0.45 [sec] delay during ascending and 1.76 [sec] during descending. The UAV could control the contact force with mean error 1.61 ± 1.08 [N] while the desired contact force was 3 [N].

KINEMATIC AND JACOBIAN ANALYSIS APPROACH FOR THE FOUR-LEGGED ROBOT

This paper presents forward kinematics, inverse kinematics and Jacobian analysis of four-legged robot research. The kinematics analysis is the main problem of the legged robot. The four-legged robots are very complex more than wheeled robots. In this study,the four-legged robot of each leg calculates Denavit-Hartenberg (D-H) method,that is used for forward kinematics and the inverse is used the geometrical and mathematical methods.The Kinematic divided into two categories Forward Kinematic and Inverse Kinematics. The forward kinematic is calculated we knew the leg of endpoint position for the angles (θ1,θ2 and θ3 ). . Inverse kinematics is used to compute the joint angles which will achieve a desired position and orientation of the end-effector relative to the base frame. The Jacobian is one of the most important analyses for controlling smooth trajectory planning and execution in the derivation of the dynamic equation of robot motion.For calculation is used MATLAB software and robot modeling is used Simulink toolbox in MATLAB software. A program is obtained that calculate joint of angular velocity and angles to move from the desired position to target position. In this study are given different angular velocity and angle of the endpoint of the leg. The work mainly focuses on mechanical design, calculation of kinematic analysis, Jacobian function and experiment data of four-legged robots in MATLAB simulation.

Automatic Groove Measurement and Evaluation with High Resolution Laser Profiling Data

Grooving is widely used to improve airport runway pavement skid resistance during wet weather. However, runway grooves deteriorate over time due to the combined effects of traffic loading, climate, and weather, which brings about a potential safety risk at the time of the aircraft takeoff and landing. Accordingly, periodic measurement and evaluation of groove performance are critical for runways to maintain adequate skid resistance. Nevertheless, such evaluation is difficult to implement due to the lack of sufficient technologies to identify shallow or worn grooves and slab joints. This paper proposes a new strategy to automatically identify airport runway grooves and slab joints using high resolution laser profiling data. First, K-means clustering based filter and moving window traversal algorithm are developed to locate the deepest point of the potential dips (including noises, true grooves, and slab joints). Subsequently the improved moving average filter and traversal algorithms are used to determine the left and right endpoint positions of each identified dip. Finally, the modified heuristic method is used to separate out slab joints from the identified dips, and then the polynomial support vector machine is introduced to distinguish out noises from the candidate grooves (including noises and true grooves), so that PCC slab-based runway safety evaluation can be performed. The performance of the proposed strategy is compared with that of the other two methods, and findings indicate that the new method is more powerful in runway groove and joint identification, with the F-measure score of 0.98. This study would be beneficial in airport runway groove safety evaluation and the subsequent maintenance and rehabilitation of airport runway.

Development of reaching during mid-childhood from a Developmental Systems perspective.

Inspired by the Developmental Systems perspective, we studied the development of reaching during mid-childhood (5–10 years of age) not just at the performance level (i.e., endpoint movements), as commonly done in earlier studies, but also at the joint angle level. Because the endpoint position (i.e., the tip of the index finger) at the reaching target can be achieved with multiple joint angle combinations, we partitioned variability in joint angles over trials into variability that does not (goal-equivalent variability, GEV) and that does (non-goal-equivalent variability, NGEV) influence the endpoint position, using the Uncontrolled Manifold method. Quantifying this structure in joint angle variability allowed us to examine whether and how spatial variability of the endpoint at the reaching target is related to variability in joint angles and how this changes over development. 6-, 8- and 10-year-old children and young adults performed reaching movements to a target with the index finger. Polynomial trend analysis revealed a linear and a quadratic decreasing trend for the variable error. Linear decreasing and cubic trends were found for joint angle standard deviations at movement end. GEV and NGEV decreased gradually with age, but interestingly, the decrease of GEV was steeper than the decrease of NGEV, showing that the different parts of the joint angle variability changed differently over age. We interpreted these changes in the structure of variability as indicating changes over age in exploration for synergies (a family of task solutions), a concept that links the performance level with the joint angle level. Our results suggest changes in the search for synergies during mid-childhood development.

Reduced Kinematic Redundancy and Motor Equivalence During Whole-Body Reaching in Individuals With Chronic Stroke

Kinematic redundancy of the human body provides abundant movement patterns to accomplish the same motor goals (motor equivalence). Compensatory movement patterns such as excessive trunk displacement in stroke subjects during reaching can be viewed as a consequence of the motor equivalent process to accomplish a task despite limited available ranges in some joints. However, despite compensations, the ability to adapt reaching performance when perturbations occur may still be limited when condition-specific changes of joint angles are required. We addressed this hypothesis in individuals with and without stroke for reaching a target placed beyond arm reach in standing while flexing the hips (free-hip condition). In randomly selected trials, hip flexion was unexpectedly blocked, forcing subjects to take a step (blocked-hip condition). In additional trials, subjects took an intentional step while reaching the target (intentional-step condition). In blocked-hip trials, healthy subjects maintained smooth and precise endpoint trajectories by adapting temporal and spatial interjoint coordination to neutralize the effect of the perturbation. However, the ability to produce motor equivalent solutions was reduced in subjects with stroke, evidenced by substantial overshoot errors in endpoint position, reduced movement smoothness and less adaptive elbow-shoulder interjoint coordination. Movement adaptability was more limited in stroke subjects who used more compensatory movements for unperturbed reaching. Results suggest that subjects with mild-to-moderate stroke only partially adapted arm joint movements to maintain reaching performance. Therapeutic efforts to enhance the ability of individuals with stroke to find a larger number of task-relevant motor solutions (adaptability) may improve upper limb recovery.

多項式カオス法を用いた不確かさを持つロボットアームの先端位置精度解析

In this paper, a novel analysis method using polynomial chaos methos is proposed for analyzing the accuracy of the endpoint position of N-DoF manipulators with uncertainty. The effectiveness of the proposed method is verified through an analysis example. The proposed method models a manipulator by using probabilistic models. The endpoint position is expressed as a probabilistic distribution by the modeling. The probabilistic distribution is calculated by polynomial chaos method. From the distribution, a measurement for accuracy of the endpoint position of the manipulator is calculated. To verify the effectiveness of the proposed method, the accuracy of the endpoint position of a double link manipulators with uncertainty in the length of the arms is analyzed by the proposed method. We confirmed that the analysis result by the proposed method is equal to the analytical solution of the manipulator with sufficient accuracy.

Manikin Laryngoscopy Motion as a Predictor of Patient Intubation Outcomes: A Prospective Observational Study

The goal of this study was to determine whether motion parameters during laryngoscopy in a manikin differed with experienced operators versus novice trainees and whether motion measurements would predict trainee outcomes when intubating patients. Motion, force, and duration of laryngoscopy on a manikin were compared in two separate experiments between beginning anesthesiology residents (CA1) and anesthesiologists with more than 24 months of anesthesiology training (CA3 or attendings). In one experiment, CA1 residents were also evaluated for the percentage of their laryngoscope path that followed the route used by attending anesthesiologists. The residents were then observed for patient intubation outcomes for 4 weeks after manikin testing. The relationship between manikin test metrics and patient intubation outcomes was analyzed by multilevel modeling. CA1 residents positioned the laryngoscope blade farther right and with less lift than did experienced anesthesiologists. Endpoint position was 0.6 ± 0.3 cm left of midline for residents (n = 10) versus 2.7 ± 0.3 cm for advanced anesthesiologists (n = 8; P = .0003), and 15.6 ± 0.8 versus 17.7 ± 0.2 cm above the table surface, respectively (P = .033). On average, only 74 ± 6% of the CA1 laryngoscopy trajectory coincided with the Attending Route (P < .001 versus 100%). For each percentage point increase in Attending Route match, residents' odds of intubating a patient's trachea improved by a factor of 1.033 (95% confidence interval [CI] 1.007-1.059, P = .040), and their rate of failed laryngoscopy attempts decreased by a factor of 0.982 (0.969-0.996, P = .045). Laryngoscopy motion in manikins may predict which trainees can complete a patient intubation successfully in a few attempts. The assessment could help determine readiness for intubating patients with indirect supervision.

Role of digit placement control in sensorimotor transformations for dexterous manipulation.

Dexterous manipulation relies on the ability to modulate grasp forces to variable digit position. However, the sensorimotor mechanisms underlying such critical ability are not well understood. The present study addressed whether digit force-to-position modulation relies entirely on feedback of digit placement and force, or on the integration of such feedback with motor commands responsible for digit positioning. In two experiments, we asked 25 subjects to estimate the index fingertip position relative to the thumb (perception test) or to grasp and lift an object with an asymmetrical mass distribution while preventing object roll (action test). Both tests were performed after subjects' digits were placed actively or passively at different distances (active and passive condition, respectively) and without visual feedback. Because motor commands for digit positioning would be integrated with position and force feedback in the active condition, we hypothesized this condition to be characterized by greater accuracy of digit position estimation and digit force-to-position modulation. Surprisingly, discrimination of digit position and force-to-position modulation was statistically indistinguishable in the active and passive conditions. We conclude that voluntary commands for digit positioning are not essential for accurate estimation of finger position or modulation of digit forces to variable digit position. Thus digit force-to-position modulation can be implemented by integrating sensory feedback of digit position and voluntary commands of digit force production following contact.NEW & NOTEWORTHY This study was designed to understand the sensorimotor mechanisms underlying digit force-to-position modulation required for manipulation. Surprisingly, estimation of relative digit position and force-to-position modulation was accurate regardless of whether the digits were passively or actively positioned. Therefore, accurate estimation of digit position does not require an efference copy of active digit positioning, and the hypothesized advantage of active over passive movement on estimation of end-point position appears to be task and effector dependent.

BlindType

Eyes-free input is desirable for ubiquitous computing, since interacting with mobile and wearable devices often competes for visual attention with other devices and tasks. In this paper, we explore eyes-free typing on a touchpad using one thumb, wherein a user taps on an imaginary QWERTY keyboard while receiving text feedback on a separate screen. Our hypothesis is that users can transfer their typing ability obtained from visible keyboards to eyes-free use. We propose two statistical decoding algorithms to infer users’ eyes-free input: the absolute algorithm and the relative algorithm. The absolute algorithm infers user input based on the absolute position of touch endpoints, while the relative algorithm infers based on the vectors between successive touch endpoints. Evaluation results showed users could achieve satisfying performance with both algorithms. Text entry rate was 17-23 WPM (words per minute) depending on the algorithm used. In comparison, a baseline cursor-based text entry method yielded only 7.66 WPM. In conclusion, our research demonstrates for the first time the feasibility of thumb-based eyes-free typing, which provides a new possibility for text entry on ubiquitous computing platforms such as smart TVs and HMDs.

Fuzzy Control Strategy for a Hexapod Robot Walking on an Incline

In this paper, the fuzzy control strategy for a hexapod robot walking on an incline is proposed. In order to maintain the vertical projection of the center of gravity (COG) remaining in the support pattern, the robot’s posture is adjusted by a fuzzy controller depending on the slope of incline. At first, Denavit–Hartenberg convention is applied to calculate the positions of motors and end points of legs. When the robot is walking on an incline, a rotation matrix, which can be acquired by an inertial measurement unit settled on the center of robot’s body, is required to obtain the vertical projection of COG. Then, the fuzzy controller is designed to adjust the angles of motors for supporting legs such that the vertical projection of COG approaches the COG of support polygon. Finally, several experiments are implemented by a hexapod robot to demonstrate the effectiveness of the proposed fuzzy control strategy.

A study on hovering motion of the underwater vehicle with umbilical cable

The paper presents a new modeling of the behavior of an underwater vehicle (UV) operating in the littoral sea, including the umbilical cable (UC) effect, where we derive a new simulation method of the full equations of the combined rigid body motion of a UV and flexible motion of the UC.In the modeling of flexible UC dynamics, we establish the governing equations of the UC dynamics based on the catenary equation method, and apply the shooting method to solve the two-point boundary value problem of the catenary equation. Using this, we propose a new formulation and solution of the governing equations to estimate the space position and forces of the UC end point under the action of concentrated and distributed forces due to underwater currents.We propose a new mathematical model on the hydrodynamics of a UV affected by the UC dynamics. For this, we map the applied forces of the UC to the dynamics of the UV through rotation matrices, and perform computer simulations to analyze the derived modeling of the UV affected by the UC dynamics. We perform simulations on the UV motion, including surge, heave, sway, and turning motions, for the cases with the UC and without the UC effect, and discuss their results.

Erosion-Inspired Simulation of Aging for Deformation-Based Head Modeling

Simulation of age progression of 3D head models is an open problem in the field of computer graphics. Existing methods usually require a large set of training data, which may not be available. In this paper, a method for aging simulation of models created by deformation-based modeling is proposed that requires no training data. A user defines the position of wrinkles by selecting the position of endpoints of the desired wrinkles and the wrinkles are then generated using an erosion-inspired approach. The method can be used to simulate aging of any head model, however, if used for models created by deformations of a base model, the erosion factors can be calculated only for the base model and applied to the derived models. The results show that the approach is capable of creating visually plausible aged models.