Synchronous Motion Research Articles

Chatter prediction for parallel mirror milling of thin-walled parts by dual-robot collaborative machining system

Thin-walled parts with double-sided features are widely used in the aerospace industry, but the machining of such parts still faces great challenges due to their weak rigid structure and the positioning errors caused by turning/re-clamping of the workpiece. For this purpose, a novel machining approach for parallel mirror robotic milling of thin-walled parts is proposed. Different from conventional single-sided milling, it can simultaneously machine both sides of the workpiece while avoiding the above problems and improving machining efficiency. However, the introduction of multiple cutting excitations makes the vibration behavior of the workpiece more complicated, thus making it difficult for the dynamic modeling of the dual-robot machining system. This paper aims to uncover the dynamic mechanism of chatter phenomenon in parallel mirror robotic milling process in consideration of the interaction of tool-workpiece-tool system. A dual-robot collaborative machining system is first developed for the milling of thin-walled workpiece, and the method of synchronous motion planning for dual robots is described. The slave robot synchronously follows the master robot and the two milling cutters mounted on tool flange of the robot are kept in mirror position. Over a tooth passing period, the engagement state of the cutters and the workpiece is analyzed considering the effect of rotation phase lag (RPL) between the twin cutters. After that, the vibration state and the corresponding instantaneous displacement of the workpiece can be expressed explicitly, then the dynamic resultant cutting force acting on the workpiece is calculated according to the mechanistic force model. Comprehensively considering the dynamic interaction of the tool-workpiece-tool system, multi-mode and position-dependent modal characteristics of thin-walled part, a time-varying delay differential equation is constructed and solved to explore the dynamical behavior of parallel mirror milling process. The predicted stability lobe diagram is validated by a series of parallel mirror milling tests on thin-walled PMMA plates. Comparisons of numerical and experimental results show that the dynamic model successfully predicts the chatter stability for the parallel mirror milling of thin-walled parts.

An efficient method for measuring and identifying geometric and dynamic errors in dual five-axis machine tools

The dual five-axis machining machine is state-of-the-art equipment designed for producing thin-walled aerospace parts like skins and panels. It comprises two five-axis machine tools with mirrored synchronous motions: one bi-rotary machine for milling and the other machine for follow-up support. The high absolute accuracy of the five-axis machine tools themselves and the high synchronous motion accuracy between the two machines are both crucial to ensure machining accuracy. This paper proposes an efficient method to measure and identify geometric and dynamic errors of dual five-axis machine tools. Using the R-test combined with three measurement trajectories to measure the absolute motion error of two five-axis machine tools and the synchronous motion error between the two machines. The designed trajectories include the main rotary axis linkage conditions and can fully reflect the primary motion forms of the dual five-axis machine tool. The main position-independent geometric errors and rotational axis linkage dynamic errors are identified by converting quasi-static and dynamic measurement data from three different trajectories into a unified reference coordinate system. The entire process requires only one instrument installation, effectively avoiding time-consuming repetitive installations and calibration processes while reducing the impact of installation errors on results. The effectiveness of the proposed method for measuring and identifying the geometric and dynamic errors is analyzed combined with Monte Carlo simulation. Experiments were carried out on a dual five-axis mirror milling system (MMS) with a 5000 mm X-stroke. Both simulations and experiments confirmed that the proposed method is efficient in quickly identifying key error sources of the MMS.

A Dual-Arm Robot Cooperation Framework Based on a Nonlinear Model Predictive Cooperative Control

Dual-arm robots show better task adaptability but face more constraints than single-arm robots. Inspired by human cooperation options, a nonlinear model predictive cooperative control (NMPCC) coupled with a cooperative index is proposed in this article. By adjusting the cooperative index, dual-arm cooperation can be classified into four modes: tracking, motion synchronization, impedance, and force priority. Thus, the cooperation operation problem is converted to a multiobjective optimization problem. Then, a nonlinear model predictive solver coupled with the ACADO toolkit is designed to solve the multiobjective optimization problem, where the robotic torque control input can be calculated in real time (less than 1 ms). The motion synchronization, cooperative transportation, and human dual-arm robot interaction experiments were conducted on dual Franka panda robots. Experiments reveal that the NMPCC control coupled with the cooperative index is easy to apply in dual-arm robots and can adapt to different complex manipulation tasks.

Assembly-Oriented Finite-Time Coordinated Control of Underactuated Dual Rotary Cranes for Payload Position and Attitude Regulation

With strong load capacity and high maneuverability of payload attitude regulation, dual rotary cranes (DRCs) are widely applied for transportation and assembly tasks in infrastructure construction. For DRCs, to achieve safe and accurate control of the payload position and attitude, it is necessary to enhance the motion synchronization of two cranes, under the premise of controlling more state variables with fewer control inputs based on nonlinear coupling dynamics; moreover, the finite-time convergence of positioning errors is also expected to be guaranteed for high efficiency. To this end, this paper proposes an assembly-oriented finite-time coordinated controller <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">without</i> any linearization to the nonlinear crane dynamics, which realizes accurate and stable regulation of the payload position and attitude through coordinated boom motions. To our knowledge, the proposed controller provides the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">first</i> closed-loop control solution to realize both horizontal and non-horizontal payload hoisting for DRCs based on practical assembly demands. Theoretically, through elaborate design of the synchronization error and coupling errors, the real-time information exchange between the two cranes is realized for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">first</i> time, which enhances the boom motion synchronization while suppressing payload swings. Furthermore, by introducing continuous terminal sliding mode surfaces with a multi-layer nested structure, the finite-time convergence of the boom positioning errors and the synchronization error is ensured with chattering reduction. Additionally, rigorous closed-loop stability analysis is provided based on Lyapunov techniques and Barbalat’s Lemma. Finally, the effectiveness and robustness of the proposed controller are verified by hardware experimental results. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This paper is motivated by the coordinated motion control problem of dual rotary cranes (DRCs), which aims to achieve safe and accurate control of the payload position and attitude oriented on practical assembly demands. At present, most control methods for DRCs only realize horizontal payload transportation, which not only ignores the requirements of payload attitude regulation in assembly tasks, but also lacks the guarantee for boom motion coordination and the finite-time convergence of state variables. To address these issues, based on the nonlinear crane dynamics <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">without</i> any linearization, this paper proposes an assembly-oriented finite-time coordinated controller for DRCs, which achieves precise and stable regulation of the payload position and attitude through coordinated boom motions, and simultaneously enhances the system rapidity by ensuring the finite-time convergence of boom positioning errors. Furthermore, the detailed controller design and stability analysis process is provided, and the effectiveness of the proposed method is verified by hardware experiments. In the future research, we will try to apply the proposed method to practical operations of DRCs for complex assembly tasks of large heavy objects.

Analysis of non-spool throttle flow dividers for synchronous hydromechanical drives

Relevance and goals. Hydraulic drives of modern mobile machines and technological equipment are, as a rule, branched and multi-circuit. At the same time, there is often a need to ensure synchronous (coordinated) movement of two or more independent hydraulic motors. The analysis of the conducted studies has shown that throttle flow dividers are the most suitable for providing automatic control of hydraulic drives. The use of spool flow dividers in general-purpose hydraulic drives, especially if they work in harsh conditions with high dustiness of the environment is impractical. Materials and methods. The article provides an overview of existing designs of non-spool throttle flow dividers for synchronous hydromechanical drives, their design schemes and operating principle are given. A comparative analysis of the functions performed by them and the quality of work is carried out. Suggestions are given on the principles of selecting a particular design of the flow divider, depending on the operating conditions. Results. A scheme of a test bench for piston hydraulic cylinders with energy recovery is proposed. A mathematical model of the stand has been developed and an example of a preliminary calculation of its functioning is given. Conclusions. The conclusion is made about the design features that make it possible to ensure the synchronous operation of hydraulic drives with high accuracy at minimal cost.

Complex Motion Behavior and Synchronization Analysis of Heterogeneous Neural Network

Complex Motion Behavior and Synchronization Analysis of Heterogeneous Neural Network

Finite-Time Synchronous Motion Control for Pneumatic Muscle-Actuated Parallel Robots in Cartesian Space

Finite-Time Synchronous Motion Control for Pneumatic Muscle-Actuated Parallel Robots in Cartesian Space

Dizajn i razvoj troškovno-efikasne robotske ruke sa robotskim kontrolerom baziranim na PLC-u

To develop a cost-efficient robot arm for a typical pick and place application that can applied in industry, this paper deployed a programmable logic controller (PLC) to control the rotation motion of the robot joints. The main tasks of the PLC controller are to calculate the kinematics, create high-speed pulse outputs for stepper motors, and implement sequence operations for a certain application. Functions are written into subprogram segments. When needed, the main program only turns on the corresponding flag for executing the subprogram. Using the pre-written subprograms, a logical sequence to implement the Pick and Place application is easily implemented and described in this paper. The PLC program is developed to control a SCARA robot with three rotation joins. Stepper motors drive the robot joints. The Delta DVPSV2 PLC is utilized to design the robot controller. This PLC series has four high-speed pulse output pins, which is suitable for this project. Synchronous motion of stepper motors is easily performed using high-speed pulse output commands built into the PLC program. Experimental results of robot arm control have demonstrated the efficiency and accuracy of the developed program. The robot arm's forward and inverse kinematics problems are verified using the simulator on the software. The robot's joints move synchronously as required to perform pick-and-place applications.

VISION-BASED MODAL ANALYSIS OF MACHINE TOOL SYSTEMS: PROGRESS AND PROSPECTS

Modal analysis of machine tools involves estimating natural frequencies, damping ratios, and mode shapes from the vibratory response of the machine tool. Usually, modal hammers and shakers are used to excite, and accelerometers or laser vibrometers are used to measure the response. Though these procedures have become routine, sometimes the use of accelerometers can result in mass-loading that distorts the response, and though laser vibrometers are non-contact, their use is precluded by their high costs. To counter these issues, vision-based modal analysis methods have emerged as a viable and promising alternative. The spatiotemporal response is estimated by treating every pixel in every frame in the video of the vibrating machine as a motion sensor. Image processing schemes leveraged from developments in allied fields are then used to register motion from video. The method is noncontact, full field, and only needs a camera and post-processing on a computer, and as such, it offers advantages over the traditional measurement methods. Since vision-based methods are potentially paradigm-shifting, this paper reviews the recent progress to contextualize the prospects of the method. The review includes discussions on selection considerations of cameras and acquisition parameters, on using markers and the machine's own features to register motion, on the efficacy of different motion registration schemes, and workarounds for when motion is spatiotemporally aliased. The paper concludes by discussing challenges and prospects related to motion synchronization, measuring speed and time-varying dynamics, and technological trends that may aid the adoption of the method.

A Systematic Literature Review: Facial Expression and Lip Movement Synchronization of an Audio Track

A Systematic Literature Review: Facial Expression and Lip Movement Synchronization of an Audio Track

The mirror therapy effectiveness as a part of physical rehabilitation program of servicemen after lower limb amputation due to mine-explosive injury

Introduction. The article considers the possibilities of using the developed program of physical therapy for military personnel after amputation of the lower limbs due to mine-explosive injury with the use of kinesiotherapy and mirror therapy for phantom pain syndrome in the conditions of trauma hospitals. Mirror therapy is an additional method of motor rehabilitation and can be used both in a hospital and independently by the patient at home. The application of this method does not require significant time expenditure for the specialist or significant financial costs for the institution or the patient.&#x0D; Purpose. To determine the effectiveness of the physical therapy program for military personnel after amputation of the lower limbs due to mine-explosive injury.&#x0D; Materials and methods. The following methods were used to solve the tasks: analysis of scientific and methodical literature; methods of researching violations of structures, functions, limitations of activity and participation according to the ICF; generally accepted methods of medical statistics. In the course of the study, the condition of the patients was monitored for the effective construction of a physical therapy program, which included therapeutic exercises in the form of mirror therapy to reduce pain in the postoperative period. Also, this method was used to reduce pain in the stump.&#x0D; Result. The patients of the selected groups had a significant phantom pain syndrome, which increased in the evening, was evaluated by the visual-analog pain scale, and was from 7 to 9 points at rest. The VAS survey was conducted before and after the mirror therapy session. Peculiarities of mirror therapy: 1) to improve motor function: simple (basic) and functional movements are performed. Therapy is strictly individualized, the technique depends on the strength of the "mirror illusion" and the severity of motor function impairment; 2) for the purpose of correcting neglect, bilateral sensory stimulation is performed and observation of different hand positions in the mirror; 3) to reduce hypertension: unilateral movements are performed with a healthy limb; 4) to restore sensitivity: bilateral sensory stimulation is performed, that is, bilateral synchronous movements are performed; 5) to reduce the pain syndrome: unilateral motor and sensory exercises are performed with the healthy limb. The advantage of the technique of mirror therapy is its effectiveness, simplicity, safety and availability, the possibility of independent use by the patient. This technique corresponds to the basic principles of motor rehabilitation – high intensity and repetition of goal-oriented tasks in combination with feedback.&#x0D; Conclusions. Conducted studies using the mirror therapy method in people with amputation of the lower limb due to mine-explosive injury show that this method of physical therapy can be an effective way to reduce the level of phantom pain, pain in the stump. Also, during the application of mirror therapy, an increase in the amplitude of joint mobility is observed.

Riders' Effects on Horses-Biomechanical Principles with Examples from the Literature.

Movements of the horse and rider in equestrian sports are governed by the laws of physics. An understanding of these physical principles is a prerequisite to designing and interpreting biomechanical studies of equestrian sports. This article explains and explores the biomechanical effects between riders and horses, including gravitational and inertial forces, turning effects, and characteristics of rider technique that foster synchronous movement with the horse. Rider symmetry, posture, and balance are discussed in the context of their relationship to rider skill level and their effects on the horse. Evidence is presented to support the feasibility of improving equestrian performance by off-horse testing followed by unmounted therapy and exercises to target the identified deficiencies. The elusive quality of harmony, which is key to a true partnership between riders and horses, is explored and described in biomechanical terms.

Load-suspended power backpack for labor saving and energy harvesting from human walk

Long-distance walk with a heavy load such as hiking and field rescue, often leads to accumulative fatigue. And continuous energy support for wearable electronics is often demanded in remote areas. Here, we report a new load-suspended power backpack that can realize labor saving and energy harvesting from human walking. An innovative suspended system is designed to decouple the synchronous movement of backpack and body, which consists of two elastomer-pulley block units and two linear sliding rod units. It also utilizes a new charge pumping technology of triboelectric nanogenerator (TENG) for high-efficient energy conversion, achieved by a specially designed main TENG and two buffer capacitors (BFCs). The main TENG has one top electrode but two bottom ones to build two separated plate variable capacitors for charge storage. The new technology is characterized by using one top electrode to synchronously drive shuttling charges in four pathways between main TENG and BFCs, and generating electricity based on shuttling charges. Consequently, it can reduce the remarkable 32.6% vertical vibrations of load and 26.7% wearing force and provide a high voltage of 820 V and a current of 103.2 μA. The average power in one current pathway is calculated to 84.1 mW (336.4 mW for four ones) with an effective power density of 29.96 mW/g, high enough to light 354 small LEDs, 235 large LEDs, the electronic watch and thermos-hygrometer. The backpack can not only be applied to relieve accumulative fatigue, but also has great potential to be an energy source for continuously driving wearable electronics for various applications.

The « jingle-jangle fallacy » of empathy: Delineating affective, cognitive and motor components of empathy from behavioral synchrony using a virtual agent

Empathy is a multidimensional construct, which has been subject to many conceptualizations (affective, cognitive, and motor components). The present investigation delineated relationships between empathy facets, using questionnaires and a motor task measuring synchrony, a non-verbal component of social interactions. Participants (N = 276) completed self-report trait measures of affective, cognitive and motor empathy. A subsample (N = 202) executed synchronous movement with a virtual agent driven by a dynamical model of behavioral synchrony. Confirmatory Factor Analyses (CFA) revealed associated, yet distinct constructs of affective and motor empathy, distinguishing somatic and kinesthetic facets. Synchrony scores were associated with affective and cognitive empathy, highlighting the role of the capacity to experience and predict others' emotions and mental states for behavioral synchrony. Yet, synchrony scores were negatively associated with kinesthetic empathy, stressing the distinction between self-report measures of motor empathy from effective behavioral synchrony. These findings support a convergence of empathy and synchrony research fields to better understand their respective contribution in non-verbal social interactions.

Mechanical Design and Experiments of a New Rotational Variable Stiffness Actuator for Hybrid Passive–Active Stiffness Regulation

To improve collision safety in robot–human collaborative applications, increasing attention has been paid to rotational variable stiffness actuators. A new rotational variable stiffness actuator, which works in two stages, is proposed for hybrid passive–active stiffness regulation. The passive stage is based on the motions of springs driven by the rack-and-pinion systems, elastically converting the shaft’s rotation into the inner shell rotation fixed to the internal gear of the active stage. The active stage is designed to achieve the movement of the pivot point located on the roller actuated by the adjustment motor, providing the output angle of the output shaft. The two pairs of rack-and-pinion systems of the passive stage and the two pairs of planetary gears of the active stage are designed for side-by-side placement, improving the stability and balance of the stiffness regulation process. Two symmetrical cam-slider mechanisms acting as leverage pivots ensure the synchronous movements of the two rollers. The variable stiffness actuator is designed and validated by simulations and experiments. Strength analysis and stiffness analysis are presented. The designed actuator can obtain the range of stiffness adjustment of 35–3286 N·mm/deg. The range of the angle difference between the input and output shafts is ±48°.

Two-dimensional synchronous motion modulation MEMS structure for suppressing 1/f noise in magnetoresistive sensors

Magnetoresistive (MR) sensors have great application prospects in the field of weak magnetic field detection due to their high sensitivity, small size, and low power consumption. However, 1/f noise greatly limits the low-frequency detectivity of MR sensors. In order to suppress 1/f noise, this paper proposes a two-dimensional synchronous motion modulation (TDSMM) structure based on microelectromechanical systems (MEMS). This structure can effectively reduce 1/f noise by modulating the frequency of the measured magnetic field in the high-frequency band. Theoretical analysis and finite element simulation were conducted on three different modulation models: TSDMM, magnetic flux concentrators motion modulation, and MR components longitudinal motion modulation. The results showed that the modulation efficiency of the TDSMM reached as high as 127%, which is currently the highest value in MR-MEMS sensors. The TDSMM MEMS structure has been successfully manufactured, and the resonant frequency of the transverse resonator is twice that of the longitudinal resonator, enabling extremely high modulation efficiency. The noise spectral density of giant-magnetoresistive components on a silicon-on-insulator substrate was tested, and the noise level in the high-frequency band was three orders of magnitude lower than that in the low-frequency band. These results position MR-MEMS sensors with TDSMM structures as highly competitive candidates in the field of ultra-weak magnetic field detection.

Right or left-handed: are locomotion type, body size, and microhabitat related to forelimb laterality in anurans?

Laterality, the tendency of animals to use the structures on one side of the body more frequently or efficiently than the other side, can reflect the evolutionary history of species, their ecological characteristics, and cognitive abilities. Using anurans as a model system, it has been hypothesized that the strength of laterality (measured as the percentage of right-handed individuals) is higher in terrestrial and arboreal species, which exhibit asynchronous locomotion type (e.g., walking, climbing), than in aquatic species where synchronous locomotion type (e.g., swimming) predominates. We tested these predictions, including body size as an additional factor, in 19 Neotropical anuran species. For this, we obtained data on forelimb use preference for individuals of such species. We then combined these data with published data for another 14 anuran species obtained through a systematic review of the literature. The combined dataset was used to perform a phylogenetic comparative analysis to verify the strength of laterality in the species. We found that four out of the 19 tested species show a percentage of right-handed individuals that was higher or lower than expected by chance. Individuals of these four species exhibit asynchronous movements of forelimbs during displacements, foraging behaviors, sexual displays, or agonistic interactions. Results of a phyloANOVA and a phyloANCOVA indicated that the strength of laterality was higher in species with asynchronous movements, but this was unrelated to microhabitat and body size. Asynchronous (i.e., non-simultaneous) movements of limbs imply alternating muscle contractions and a higher neural asymmetry than synchronous (i.e., simultaneous) movements of limbs. Therefore, species with an asynchronous locomotion type could be reflecting such complexity and neural asymmetry in higher levels of forelimb laterality. Our results mostly support the predictions based on models that cover the expected relationship between the strength of laterality and the evolutionary ecology of vertebrates.

Calibration of link errors in rotary axes of five-axis machine tools using a six-dimensional motion measuring device

In this study, the position-independent geometric errors (PIGEs) of five-axis machine tools are identified and calibrated using a Stewart–Gough platform (SGP) based Motion Measuring Device (MMD). As the MMD of micrometer-level accuracy is cable of six-dimensional pose measurements, a closed kinematic chain is established by installing the upper and lower plate of the MMD to the spindle and rotary worktable of the machine tool, respectively. Particularly, the sensor-mounting misalignments, which are inevitable but mostly ignored in the previous PIGE identification methods, are formulated and identified together with the PIGEs. Thus, the sensor-mounting misalignments will not affect the accuracy of PIGE calibration. The proposed method is verified by simulation and experimental results. The synchronous motion test (SMT) demonstrates that the five-axis machine tool owns a high accuracy of 5 micrometers in the tested motion range after PIGE calibration.

The effects of synchronous and asynchronous steady-state auditory-visual motion on EEG characteristics in healthy young adults

The brain’s integration of motion information from visual and auditory senses is essential for human to be able to duly respond to the dynamic living environment. Research on the impact of steady-state auditory motion and steady-state visual motion synchronous stimuli and minor asynchronous stimuli on electroencephalogram (EEG) is lacking. This study designed steady-state visual motion paradigms, steady-state auditory motion paradigms, steady-state auditory-visual synchronous motion paradigms, and steady-state auditory-visual asynchronous motion paradigms. Then the effects of steady-state auditory-visual motion stimuli on EEG were analyzed from the aspects of time domain, frequency domain, connectivity, and source localization. Our study showed that the synchronous steady-state auditory-visual motion stimuli and the asynchronous steady-state auditory-visual motion stimuli can enhance brain responses in a subadditive mode and significantly activated auditory and visual integration areas compared to single-modal visual and auditory stimuli. Moreover, asynchronous steady-state auditory-visual motion stimuli activated the Anterior Cingulate (ACG) compared to synchronous steady-state auditory-visual motion stimuli. Our study demonstrated that ACG regions were involved in conflicting processing of steady-state auditory-visual motion information. This study further enriches the cutting edge of auditory-visual motion integration.

The interaction between neuromuscular forces, aerodynamic forces, and anatomical motion in the upper airway predicts the severity of pediatric OSA.

Upper airway neuromuscular response to air pressure during inhalation is an important factor in assessing pediatric subjects with obstructive sleep apnea (OSA). The neuromuscular response's strength, timing, and duration all contribute to the potential for airway collapses and the severity of OSA. This study quantifies these factors at the soft palate, tongue, and epiglottis to assess the relationship between neuromuscular control and OSA severity in 20 pediatric subjects with and without trisomy 21, under dexmedetomidine-induced sedation. The interaction between neuromuscular force and airflow pressure force was assessed based on power transferred between the airway wall and airflow calculated from airway wall motion (from cine magnetic resonance images) and air pressure acting on the airway wall (from computational fluid dynamics simulations). Airway wall motion could be asynchronous with pressure forces due to neuromuscular activation, or synchronous with pressure forces, indicating a passive response to airflow. The obstructive apnea-hypopnea index (oAHI) quantified OSA severity. During inhalation, the normalized work done through asynchronous dilation of the airway at the soft palate, tongue, and epiglottis correlated significantly with oAHI (Spearman's ρ = 0.54, 0.50, 0.64; P = 0.03, 0.03, 0.003). Synchronous collapse at the epiglottis correlated significantly with oAHI (ρ = 0.52; P = 0.02). Temporal order of synchronous and asynchronous epiglottis motion during inhalation predicted the severity of OSA (moderate vs. severe) with 100% sensitivity and 70% specificity. Subjects with severe OSA and/or trisomy 21 have insufficient neuromuscular activation during inhalation, leading to collapse and increased neuromuscular activation. Airflow-driven airway wall motion during late inhalation likely is the main determinant of OSA severity.NEW & NOTEWORTHY This is the first study that combines cine MRI and computational fluid dynamics with in vivo synchronous respiratory flow measurement to quantify the interaction between airway neuromuscular forces, aerodynamic forces, and airway anatomy noninvasively in pediatric patients with obstructive sleep apnea (OSA). The results indicate power transfer predicts OSA severity.