Position Angle Research Articles

Comparison of upper airway volume and hyoid position after camouflage orthodontic or orthodontic-orthognathic treatment in patients with skeletal class Ⅲ malocclusion with normal-angle vertical pattern.

This study aims to compare the effects of two orthodontic treatment modalities for skeletal class Ⅲ malocclusion on specific changes in airway volume, morphology, palatal angle, mandibular rotation, and bone displacement. Results provide scientific evidence for the selection of orthodontic treatment plans and reduce the risk of developing obstructive sleep apnea hypopnea syndrome (OSAHS). Thirty-six patients diagnosed with skeletal class Ⅲ malocclusion at the Department of Orthodontics, the Affiliated Stomatological Hospital of Nanjing Medical University from September 2018 to December 2023 were divided into two groups: orthodontic-orthognathic treatment group (18 patients) and camouflage orthodontic treatment group (18 patients). Changes in airway volume, cross-sectional area, palatal angle, mandibular, and tongue positions were observed through pre- and post-operative cone beam computed tomography and 3D cephalometric measurements. In the camouflage orthodontic treatment group, nasopharyngeal volume and oropharyngeal volume statistically increased after treatment (P<0.05). In the orthodontic-orthognathic treatment group, changes in nasopharyngeal volume, nasopharyngeal airway, distance from posterior tongue to pharyngeal wall, palatal angle, mandibular rotation, and hyoid bone displacement were statistically significant after surgery (P<0.05). In the comparison between the two groups after treatment, changes in the distance from posterior tongue to pharyngeal wall, palatal angle, and distance from hyoid bone to sella turcica point were statistically significant (P<0.05). Patients in the orthodontic-orthognathic treatment group showed significantly greater changes in oropharyngeal cross-sectional area, palate angle, and tongue position compared with patients in the camouflage orthodontic treatment group. As individuals susceptible to OSAHS often exhibit mandibular retrusion and decreased minimum airway cross-sectional area, special attention should be paid to airway morphology changes when adopting orthodontic-orthognathic treatment to avoid adverse consequences.

Multifactorial Analysis of the Collapse Process of Double Bubbles Based on the Coarse-Grained Force Field in Free Domain.

Cavitation has been a hot research topic for scholars in various fields because of the intense mechanical, chemical, and thermal effects of bubble collapse. It forms a cluster of bubbles, and the bubbles will affect, interfere with, and couple with each other. To grasp the main factors affecting bubble collapse and the interbubble mechanism, the paper adopts the molecular dynamics simulation combined with the coarse-grained force field to study the collapse process of the double bubble model and takes the dynamic shape change of the bubbles, the local velocity distribution, and the local pressure distribution as the object to summarize the position angle, the shock velocity, and the bubble distance on the collapse law and the primary and secondary influence relationship and then reveals the interbubble mechanism. The results show that with the increase of the position angle, the collapse velocity of the right side of bubble A gradually decreases compared with the left side, while bubble B has the opposite characteristics. When the angle is 0°, bubble A and bubble B collapse at the same time and the direction of the jet is the same as the shock direction. With the increase of the position angle, the direction of the jet is biased toward bubble B. The collapse time of bubble B gradually increases with the increase in the bubble distance. Taking the collapse time as the evaluation standard, the relationship between the three factors is shock velocity (u) > position angle (θ) > bubble distance (L). In this paper, it perfects the cavitation theory and provides technical support for the efficient application of hydrodynamic cavitation technology.

Large-Space Laser Tracking Attitude Combination Measurement Using Backpropagation Algorithm Based on Neighborhood Search

Large-space high-precision attitude dynamic measurement technology has urgent application needs in large equipment manufacturing fields, such as aerospace, rail transportation, automobiles, and ships. In this paper, taking laser tracking equipment as the base station, a backpropagation algorithm based on neighborhood search is proposed, which is applied to the fusion of multi-source information for solving the dynamic attitude angle. This paper firstly established a mathematical model of laser tracking attitude dynamic measurement based on IMU and CCD multi-sensor, designed a 6-11-3 back propagation network structure and algorithm flow, and realized the prediction of attitude angle through model training. Secondly, the method based on neighborhood search realizes the determination of the optimal training target value of the model, of which the MSE has a 34% reduction compared to the IMU determination method. Finally, the experimental platform is set up with the precision rotary table as the motion carrier to verify the effectiveness of the research method in this paper. The experimental results show that with the neighborhood-based backpropagation algorithm, the measurement results have a higher data update rate and a certain inhibition effect on the error accumulation of IMU. The absolute value of the system angle error can be less than 0.4° within 8 m and 0–50°, with an angle update rate of 100 Hz. The research method in this paper can be applied to the dynamic measurement of laser tracking attitude angles, which provides a new reference for the angle measurement method based on the fusion of multi-source information.

Super-Twisting Algorithm Backstepping Adaptive Terminal Sliding-Mode Tracking Control of Quadrotor Drones Subjected to Faults and Disturbances

The rapid advancement of quadrotor systems has introduced significant challenges across multiple disciplines. Among these, fault tolerance and trajectory tracking in complex environments have long been recognized as critical challenges in quadrotor control research. To address issues such as rotor performance degradation and external disturbances, a novel position-attitude control system was developed, aimed to achieve precise position and attitude tracking. Initially, a dynamic model of the quadrotor was formulated, serving as the foundation for the controller design. Super-twisting algorithm terminal sliding-mode control (STATSMC) was then employed within the position loop to suppress chattering by the super-twisting algorithm. Subsequently, a new super-twisting algorithm beckstepping adaptive terminal sliding-mode control (STABATSMC) was proposed to mitigate the controller output and merge enable adherence to the desired Euler angles in case of failure. This approach enables the quadrotor to accurately follow position commands and achieve the desired attitude angles. The introduction of terminal sliding-mode control enhances convergence speed and tracking precision, while the super-twisting algorithm mitigates chattering and smoothens the control output. Finally, a series of simulation experiments were conducted within the Simulink environment to validate the proposed control system. The experimental results are compared with the state-of-art terminal sliding-mode control method, demonstrating the superior performance and effectiveness of the proposed method.

An Improved Unscented Kalman Filter Applied to Positioning and Navigation of Autonomous Underwater Vehicles.

To enhance the positioning accuracy of autonomous underwater vehicles (AUVs), a new adaptive filtering algorithm (RHAUKF) is proposed. The most widely used filtering algorithm is the traditional Unscented Kalman Filter or the Adaptive Robust UKF (ARUKF). Excessive noise interference may cause a decrease in filtering accuracy and is highly likely to result in divergence by means of the traditional Unscented Kalman Filter, resulting in an increase in uncertainty factors during submersible mission execution. An estimation model for system noise, the adaptive Unscented Kalman Filter (UKF) algorithm was derived in light of the maximum likelihood criterion and optimized by applying the rolling-horizon estimation method, using the Newton-Raphson algorithm for the maximum likelihood estimation of noise statistics, and it was verified by simulation experiments using the Lie group inertial navigation error model. The results indicate that, compared with the UKF algorithm and the ARUKF, the improved algorithm reduces attitude angle errors by 45%, speed errors by 44%, and three-dimensional position errors by 47%. It can better cope with complex underwater environments, effectively address the problems of low filtering accuracy and even divergence, and improve the stability of submersibles.

Comparative effectiveness of the exact versus estimated angle of head position in the Epley maneuver: a randomized controlled trial.

Introduction The Epley maneuver is the recommended treatment for benign paroxysmal positional vertigo of the posterior semicircular canal (PC-BPPV). Traditionally, the angle of the patient's head in each position during the Epley maneuver is not monitored and subjectively estimated by physicians. As a result, deviations of head angles from the standard may affect the treatment result. This study aimed to compare the outcome of the Epley maneuver between the group of exact head angles and the group of subjectively estimated angles (traditional Epley maneuver). Methods A single-blind randomized controlled trial was conducted at the Department of Otolaryngology, Chiang Mai University Hospital. PC-BPPV patients were attached with the head angle measuring device and randomized into 2 groups: Group I - the exact angle group, physicians performed the Epley maneuver with accurate head angle in each step; and Group II - the estimated angle group, physicians performed the Epley maneuver by estimating the head angle (traditional Epley maneuver). The treatment outcomes were measured at 1 week in the aspects of negative Dix Hallpike results and severity of dizziness. Results Thirty-one PC-BPPV patients were recruited and randomized into Group I (15 participants) and Group II (16 participants). Both groups showed clinical improvement. Although significant deviations of head angles were observed in group II, there was no significant difference in outcomes between the two groups in terms of negative Dix Hallpike and severity of dizziness at the 1-week follow-up. Conclusion Although significant variations of head angles were observed during the traditional Epley maneuver by experienced physicians, these deviations were slight (less than 15°) and did not significantly affect the successful treatment outcome at 1 week, in terms of negative Dix Hallpike and severity of dizziness, when compared to the group with accurate head angle during the Epley maneuver.

Results of Bioabsorbable Screws for the Fixation of Chevron Osteotomy in the Treatment of Hallux Valgus Deformities.

This study aimed to investigate the safety and reliability of using bioabsorbable screws for the fixation of chevron osteotomy in the treatment of hallux valgus (HV) deformity. Clinical cases of chevron osteotomy in the treatment of HV deformities in our hospital between December 2018 and August 2022 were retrospectively summarised to compare preoperative imaging indices with those at the final follow-up session, including the hallux valgus angle (HVA), intermetatarsal angle (IMA) and tibial sesamoid position (TSP). The American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale, short-form health survey questionnaire (SF-36) and European Foot and Ankle Society (EFAS) scale were used to assess therapeutic efficacy. The visual analogue scale (VAS) was used to assess pain relief. Moreover, complications were recorded. Twenty-six patients (39 feet) were included, and the mean follow-up period was 24.0 months. No infection, delayed healing or non-healing was recorded. The osteotomy ends healed well without non-union or delayed union. Four cases of recurrence (HVA ≥20°), two of numbness in the distal toe, one of necrosis of the first metatarsal head and one of osteoarthritis of the first metatarsophalangeal joint occurred. No patients underwent secondary surgery. The HVA, IMA and TSP significantly reduced at the final follow-up session compared with their preoperative values, and significant improvement was seen in clinical scores. The use of bioabsorbable screws for the fixation of chevron osteotomy is safe and effective in the treatment of HV deformities.

Evaluating the impact of soft bracing and textile engineering in enhancing postural control and proprioception in adolescent idiopathic scoliosis

Adolescent idiopathic scoliosis (AIS) is often associated with unbalanced posture and proprioceptive deficits and is particularly prone to progression during puberty. However, limited research has addressed early intervention for mild curves (10-20 degrees). This study aims to examine the effects of a soft bracing intervention using the Posture Correction Girdle (PCG) on 3D postural balance and proprioception in adolescents with early-stage scoliosis. Cobb angles were measured with the X-ray Imaging before and after a 2-h wear trial with the girdle to assess immediate curve reduction. Postural angles were visualized using 3D body scanning. Proprioception was assessed using a motion capture system, focusing on trunk, neck, elbow, and knee movements under the eye-open and eye-closed condition. Data were analyzed using descriptive statistics, t-tests, and Pearson’s correlation and partial Mantel tests to examine postural balance and proprioceptive outcomes. Results indicated significant improvements in postural balance in the frontal and sagittal planes, and proprioception in the dominant-side elbow. However, other proprioceptive measures showed limited changes, with responses differing by spinal curvature. Strong correlations emerged between proprioceptive function and postural angles in the thoracic and lumbar regions. These findings suggest that soft bracing can enhance postural control for mild AIS, though individual variability in responses highlights the need for personalized bracing strategies. This study supports soft bracing as a promising therapeutic option, underscoring the importance of individualized assessment to optimize brace design and effectiveness in early-onset scoliosis management.

Quaternion-Based Fast SMC–PD Cross-Domain Tracking Control for Coaxial Hybrid Aerial–Underwater Vehicle Under Oceanic Disturbances

In this study, nonsingular modeling and cross-domain trajectory tracking control problems for a special class of coaxial hybrid aerial–underwater vehicles (HAUVs) are investigated. Coaxial HAUVs need to effectively overcome the influence of hydrodynamic factors when moving underwater, so the attitude angle required by coaxial HAUVs is much larger than that in the air. The attitude representation based on quaternion modeling is adopted to avoid the inherent singularity of Euler angle modeling. A cascade sliding mode control and proportion differentiation (SMC-PD) controller is proposed, which is used to position trajectory and attitude quaternion tracking control, respectively. An adaptive sliding mode controller based on disturbance observer (DO) enhancement is adopted in the outer loop to carry trajectory tracking control. At the same time, the expected attitude angle is calculated by the outer loop (position) and is converted into the expected quaternion. With reference to the idea of enhanced robustness in active disturbance rejection control (ADRC), a feedforward proportion derivation (PD) controller based on DO enhancement is used to track the desired quaternion. A variable parameter adaptive algorithm based on the learning rate is introduced in the cascaded SMC-PD controller. The error convergence speed of the system is further improved by adaptively changing the controller parameters. The stability of the proposed control scheme is proved by using the Lyapunov theory. The numerical simulation results show that the controller has good robustness and effectiveness.

Determining the stability of a fire truck tanker against overturning while driving through crossed forest terrain

The object of this study is to consider dynamic processes in the tank of a fire truck with different levels of water filling. The task to be solved is to determine the data on the fluctuation of the center of mass of a dynamic system, which consists of the water tank of a fire truck tanker truck, when it moves through rough forest terrain at different speeds. The data make it possible to predict the danger of a fire truck tipping over. In the process of solving the task, an estimation model of a fire truck tanker truck was built together with a water tank, using the LS-Dyna dynamic systems simulation software package. In order to reproduce the dynamic impact on the fire truck tanker with the water capacity exerted by the relief of the rugged forest area, the time dependences of the angles of current position of the fire truck tanker – roll angle, yaw, and pitch – were established. The resulting dependences were used as boundary conditions to reproduce the dynamic influence of the terrain. The turning angles of the water tank of a fire truck were determined depending on the unevenness of the terrain, the geometry of which was calculated by a pseudo-random number generator. Using the explicit method for integrating the dynamics equations, implemented in the code of the LS-Dyna software package, the patterns of fluctuations of the center of mass of the water tank of the fire truck tanker depending on the level of filling and speed of movement were defined. Using results from the mathematical modeling of dynamic processes in the fire truck tanker, a numerical algorithm was developed for this fire truck tanker to maintain its stability against overturning. Therefore, the results of this study have a direct practical application in the field of fire truck tanker design safety and could be used to improve and devise new technologies in this field

Research on Response Postures of Subway Train in Straight Line Collision

A six-car subway train finite element model was developed to investigate possible response postures under impact accidents. Considering the plastic deformation of carriages and weak points of the train front, the simulation included two conditions: train–train collision and collision with an obstacle. Comprehensive response postures were obtained. A one-dimensional dynamic theory model was established to verify the rationality of the FEM model. The influence of impact speed, impact angle, and impact position on the energy consumption and response postures were discussed. The results show that one accident condition is accompanied by a variety of response postures. The main factors of climbing are asynchronism of yaw and pitch motions of adjacent carriages and plastic deformation of carriage ends, which leads to vertical arch. In oblique and front-side collision, the lateral force and the deviation of train front cause rapid derailment, and large lateral movement of the front and lateral buckling happen subsequently.

The effect of eccentricity error on the static load sharing characteristics of PTBTS based on 3D-LTCA method

Eccentricity error represents a common error form in gear transmission systems. Its presence significantly impacts the time-varying meshing stiffness (TVMS) and transmission error among gear pairs, consequently exerting a notable influence on the load sharing coefficient (LSC) of power two branching transmission system (PTBTS). In this paper, the static load sharing model of PTBTS is constructed based on the equilibrium relationships of gear pair with the consideration of position angle, meshing phase, eccentricity error and so on. Additionally, a TVMS model for multi-branching transmission system is established using the three-dimensional load tooth contact analysis (3D-LTCA) method. Finally, the stiffness model and static load sharing model are coupled to achieve precise modeling of the PTBTS static characteristics, and the impact of eccentricity error amplitude and phase on the static load sharing characteristics of PTBTS are studied. The results indicate a substantial influence of eccentricity error and eccentric phase on the load sharing characteristics of the system. As the eccentricity error amplitude increases, the load sharing performance of the system deteriorates. However, it is noteworthy that the static load sharing characteristics of the system can be enhanced by adjusting the eccentricity error phase to an appropriate setting.

Precise Measurements of the LMC Bar’s Geometry with Gaia DR3 and a Novel Solution to Crowding-induced Incompleteness in Star Counting

Abstract We present new measurements of the 2D geometry of the LMC’s stellar bar with precise astrometric observations of red clump stars in Gaia DR3. We develop a novel solution to tackle crowding-induced incompleteness in Gaia data sets with the Gaia BP-RP color excess. Utilizing the color excess information, we derive a 2D completeness map of the LMC’s disk. We find that incompleteness biases the bar measurements and induces large uncertainties. With the completeness-corrected 2D red clump map, we precisely measure the LMC bar’s properties using Fourier decomposition. The bar radius (semimajor axis) is R bar = 2.13 − 0.04 + 0.03 kpc, and its position angle is 121.°26 ± 0.°21. The bar’s strength as quantified by the Fourier bi-symmetric amplitude is S bar = 0.27, indicating that the LMC has a significant bar perturbation. We find the bar has an axis ratio of 0.54 ± 0.03, and is offset with respect to the center of the outer disk isophote at R ≈ 5 kpc by 0.76 ± 0.01 kpc. These LMC bar properties agree with a hydrodynamic model where the SMC has undergone a recent direct collision with the LMC. We compare the LMC’s bar properties with other barred galaxies in the local Universe, and discover that the LMC is similar to other barred galaxies in terms of bar-galaxy scaling relations. We discuss how our completeness correction framework can be applied to other systems in the Local Group.

Parameterized ZNCC image correlation for rotary-angle measurement

Abstract High-accuracy rotary-angle measurement is critical for precise positioning and control of robots, machine arms, and machine tools in industry. Image-based measurement is a very promising technology for angle positioning owing to its simple system, low cost, and good robustness to environments. Image correlation, such as the zero-mean normalized cross correlation (ZNCC) method, can obtain high accuracy image-positioning results, but their efficiency is too low to directly use in industries. This paper proposes to measure the absolute rotary angle using a parameterized ZNCC (PZNCC) image correlation method. The PZNCC expresses the ZNCC coefficient by the image shift parameters explicitly, so that the precise-match point corresponding to the global ZNCC maximum can be efficiently obtained and no image-resampling process is required. As a result, PZNCC is approximately 5 times faster than the classic inverse compositional Gauss–Newton (IC-GN) algorithm. Experiments show that rotary angle measurement based on PZNCC can obtain absolute angle positions with an accuracy of 1.16 arcsec (RMSE).&amp;#xD;

Preview-Based Optimal Control for Trajectory Tracking of Fully-Actuated Marine Vessels

In this paper, the problem of preview optimal control for second-order nonlinear systems for marine vessels is discussed on a fully actuated dynamic model. First, starting from a kinematic and dynamic model of a three-degrees-of-freedom (DOF) marine vessel, we derive a fully actuated second-order dynamic model that involves only the ship’s position and yaw angle. Subsequently, through the higher-order systems methodology, the nonlinear terms in the system were eliminated, transforming the system into a one-order parameterized linear system. Next, we designed an internal model compensator for the reference signal and constructed a new augmented error system based on this compensator. Then, using optimal control theory, we designed the optimal preview controller for the parameterized linear system and the corresponding feedback parameter matrices, which led to the preview controller for the original second-order nonlinear system. Finally, a numerical simulation indicates that the controller designed in this paper is highly effective.

Systemic Effects of Molar and Incisor Biting on Walking Direction With and Without Visual Feedback

Gait stability and walking direction control are conventionally attributed to coordination among somatosensory, visual, and vestibular systems. Recent evidence of functional interdependence between masticatory and neuromuscular systems indicates that the stomatognathic system is neurologically integrated with various body systems relevant to movement planning and execution. This study investigated the effects of unilateral molar biting and incisor biting on walking with and without visual feedback. A cohort of 31 healthy young adults aged 21 to 30 years (average age of 23.93 ± 1.89) participated in this study. Three types of errors in walking direction (angle error, position error, and curve error) were computed. Our findings indicate that, in right-handed individuals, irrespective of visual feedback, unilateral biting caused systematic deviations toward the biting side from initiation to termination of walking. The consistent deviation in walking, particularly during unilateral right biting conditions in right-handed individuals, may indicate a complex interplay between masticatory function and gait control mechanism, potentially influenced by handedness and motor lateralization within the cortex. This study establishes a foundation for future research exploring the interrelation between bite location, visual feedback, and motor control in diverse populations. This research may provide insight for more efficient interventions for gait-related disorders.

I-f Control Method for SynRMs Uses Simple Inductance Identification and Voltage Injection for Current and Angle Control.

The sensorless vector control method of synchronous reluctance motors (SynRMs), based on extended back electromotive force (EMF) or flux observation, has been widely applied in the medium- or high-speed range. However, in the low-speed and low-current range, the extended back-EMF and flux are nearly zero. The use of the current frequency (I-f) control method can enable the motor to pass through the low-speed region, thereby ensuring that the back-EMF and flux reach a large value. I-f control methods that are widely used in permanent magnet synchronous motors (PMSMs) may encounter many problems when applied to SynRMs. The most serious issue is the inability to adjust the current amplitude to control the rotor angle and achieve a smooth transition to sensorless control. Based on various issues, this article proposes an I-f control method with four stages that can be used in SynRMs. This method uses a simple inductance identification method to solve the flux saturation phenomenon of SynRMs and then uses high-frequency voltage injection to continuously adjust the current amplitude and rotor angle position in conjunction with this inductance identification method. The effectiveness of this method is experimentally demonstrated on a 5.5 kW SynRM.

Two-epoch spectral imagery of the outflow system PV Cep

We continue to study the structure and kinematics of Herbig-Haro (HH) flows. HH flows exhibit a large variety of morphological and kinematical structures. Proper motion (PM) and radial velocity investigations are essential for understanding the physical nature of these structures. We investigated the kinematics and PM of spectrally separated structures in the PV Cep HH flow HH 215. We present observational results we obtained with a 6 m telescope (in Russia) using the SCORPIO multi-mode focal reducer with a scanning Fabry-Perot interferometer. Two epochs of the observations of the PV Cep region in Halpha and SII emission (2003 and 2020-2021) allowed us to study the morphology of the HH 215 jet in detail and to measure the PM and radial velocities for its inner structures. We studied previously known emission knots in the HH 215 flow and new features. Moreover, a newly formed HH knot was revealed. It presumably formed during the large maximum of PV Cep in 1976-1977. We found the high-velocity inner channel in the HH 215 ionized outflow, oriented in the mean direction of the whole HH outflow, and the symmetry axis of the reflection nebula. The position angle of the HH knots located along the axis of the high-velocity channel coincide with its axis (about 325$^ circ $), but others have a completely different value (about 25$^ circ $). This supports the idea that these knots were formed by oblique shocks. We derived a value of i approx 30 for the inclination angle between the flow axis and the line of sight. The total length of the HH 215 outflow probably is about 0.2 pc, and the full length of the bipolar outflow from PV\ Cep (HH 315 + HH 215) can be estimated as 3.6 pc, assuming that the inclination angle is approximately stable.

Investigating Kozai-Lidov oscillations and disc tearing in Be star discs

Abstract Recent simulations of Be stars in misaligned binary systems have revealed that misalignment between the disc and binary orbit can cause the disc to undergo Kozai-Lidov (KL) oscillations or disc-tearing. We build on our previous suite of three-dimensional smoothed particle hydrodynamics simulations of equal-mass systems by simulating eight new misaligned Be star binary systems, with mass-ratios of 0.1 and 0.5, or equal-mass systems with varying viscosity. We find the same phenomena occur as previously for mass ratios of 0.5, while the mass ratio of 0.1 does not cause KL oscillations or disc-tearing for the parameters examined. With increased viscosity in our equal-mass simulations, we show that these phenomena and other oscillations are damped out and do not occur. We also briefly compare two viscosity prescriptions and find they can produce the same qualitative disc evolution. Next, we use the radiative transfer code hdust to predict observable trends of a KL oscillation, and show how the observables oscillate in sync with disc inclination and cause large changes in the polarization position angle. Our models generate highly complex line profiles, including triple-peak profiles that are known to occur in Be stars. The mapping between the SPH simulations and these triple-peak features gives us hints as to where they originate. Finally, we construct interferometric predictions of how a gap in the disc, produced by KL oscillations or disc-tearing, perturbs the visibility versus baseline curve at multiple wavelengths, and can cause large changes to the differential phase profile across an emission line.

ℒ1 adaptive controller of VEGA Launcher subject to flexible modes

Flexible launch vehicle modes contribute to the deterioration of its stability performance. For this reason, their influence must be considered when designing and validating appropriate solutions for its automatic control system. The first three bending modes are the most relevant for control system design and analysis. Next, considerations regarding the elastic modes of the Vega actuator, used in the simulations performed throughout this study, are presented. The IMU (Inertial Measurement Unit) measurements providing attitude angles and angular rates are strongly corrupted by the local elastic deformations resulting from structural flexibility. These measurements are fed back to the TVC (Thrust Vector Control) system which controls the pitch and the yaw motion of the vehicle. The design methodology for this control system is based on an ℒ1 adaptive technique incorporating a Butterworth filter guarantees good stability performances for wide variations of the launcher’s dynamics parameters.