Dynamic Maneuvers Research Articles

Mathematical modeling of shallow water effects on ship maneuvering

An Abkowitz-type model was extended to improve the prediction of maneuvering dynamics of inland ships in deep and shallow waters. First, additional coupled rudder and speed related hydrodynamic derivatives were added to better capture hydrodynamic forces and moments. Second, higher order drift related hydrodynamic derivatives were implemented to more reliably predict longitudinal forces. Steady RANS-based captive model tests were performed to estimate speed-dependent hydrodynamic derivatives. Unsteady captive model tests, based on applying a novel Euler equations based numerical approach, were carried out to determine acceleration-dependent zero-frequency hydrodynamic derivatives. Executed were propulsion tests, rudder tests, coupled propulsion and rudder tests, rotating arm tests, drift tests, and coupled rotating arm and drift tests, all at five water depths to draft ratios of 1.43, 1.79, 2.00, 4.00, and 8.00. Tests at the ratio 1.79 were validated against physical captive model tests, and regression analyses estimated the hydrodynamic derivatives. At each water depth, a 45 deg turning circle test, a 35/10 zigzag test, and a 45/110 evasive action test were carried out. Turning circle maneuvers were significantly influenced by shallow water. Compared to deep water, in shallow water the tactical diameter increased from 1.6L to 2.6L, and the drift angle decreased from 21 deg to about 4 deg. Compared to turning circles maneuvers, effects on the zigzag and evasive action maneuvers were relatively small in shallow water. Drift angles and yaw rates in the simulated 45 deg turning circle and a 35/5 zigzag tests agreed favorably with full-scale trials of a similar ship; however, scale effects and the slightly different hull shapes led to different speed losses.

Multiagent Manuvering with the Use of Reinforcement Learning

This paper presents an approach for defining, solving, and implementing dynamic cooperative maneuver problems in autonomous driving applications. The formulation of these problems considers a set of cooperating cars as part of a multiagent system. A reinforcement learning technique is applied to find a suboptimal policy. The key role in the presented approach is a multiagent maneuvering environment that allows for the simulation of car-like agents within an obstacle-constrained space. Each of the agents is tasked with reaching an individual goal, defined as a specific location in space. The policy is determined during the reinforcement learning process to reach a predetermined goal position for each of the simulated cars. In the experiments, three road scenarios—zipper, bottleneck, and crossroads—were used. The trained policy has been successful in solving the cooperation problem in all scenarios and the positive effects of applying shared rewards between agents have been presented and studied. The results obtained in this work provide a window of opportunity for various automotive applications.

Flight-Test Determination of Longitudinal Stability Using System Identification

In the present work, system identification methods were applied to the flight data from dynamic maneuvers in order to obtain an aerodynamic model of the longitudinal dynamics of a propeller-driven aircraft, including a model for the elevator hinge moment. As a result, the model allowed numerical computation of elevator deflections and stick forces required to trim the aircraft at different flight conditions, including variations of the center-of-gravity location. From these results, the stick-fixed and stick-free neutral points were computed. When compared to a conventional flight-test technique, the new method provided similar mean values for the neutral point location and reduced the associated uncertainty by about 50%. The data collected for system identification required only a fraction of the flight time used in conventional techniques. Moreover, the aerodynamic modeling revealed nonstandard dependencies, such as the linear influence of the airspeed and thrust coefficients on the aerodynamic coefficients. Therefore, propeller slipstream effects were automatically embedded into the neutral point results obtained.

Manoeuvre decision‐making of unmanned aerial vehicles in air combat based on an expert actor‐based soft actor critic algorithm

AbstractThe demand for autonomous motion control of unmanned aerial vehicles in air combat is boosted as taking the initiative in combat appears more and more crucial. Unmanned aerial vehicles inability to manoeuvre autonomously during air combat that features highly dynamic and uncertain manoeuvres of the enemy; however, limits their combat capabilities, which proves to be very challenging. To meet the challenge, this article proposes an autonomous manoeuvre decision model using an expert actor‐based soft actor critic algorithm that reconstructs empirical replay buffer with expert experience. Specifically, the algorithm uses a small amount of expert experience to increase the diversity of the samples, which can largely improve the exploration and utilisation efficiency of deep reinforcement learning. And to simulate the complex battlefield environment, a one‐to‐one air combat model is established and the concept of missile's attack region is introduced. The model enables the one‐to‐one air combat to be simulated under different initial battlefield situations. Simulation results show that the expert actor‐based soft actor critic algorithm can find the most favourable policy for unmanned aerial vehicles to defeat the opponent faster, and converge more quickly, compared with the soft actor critic algorithm.

A Tube-MPC Approach to Autonomous Multi-Vehicle Racing on High-Speed Ovals

Autonomous vehicle racing has emerged as vibrant, innovative technology development, demonstration platform in recent years. Universities, companies demonstrate their achievements on various vehicles - from 1:10th to full-scale prototypes. One of those platforms is the Dallara AV-21, and the spec-vehicle for the Indy Autonomous Challenge. This paper outlines the robust model predictive control (MPC) concept used within the software stack of the TUM Autonomous Motorsport team. It is based on a simplified friction-limited point mass model and a set of low-level feedback controllers. The remaining model uncertainties are managed via introducing a constraint-tightening approach based on a Tube-MPC approach. In contrast to classical tracking controllers, the optimization problem is formulated to freely optimize the trajectory while staying within certain maximum deviations of the reference. This approach allows to rely on a coarse output of the trajectory planning approach while maintaining smoothness requirements in steering, throttle, and brake actuation. The paper highlights the advantages of the proposed robust reoptimization concept compared to pure tracking formulations. It showcases the performance compared to a classical LQR controller and an MPC, which utilizes a vehicle model with a more sophisticated tire model. The controller achieved a top speed of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{265 kmh}^{-1}$</tex-math></inline-formula> and lateral accelerations up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${\text{21 ms}}^{-2}$</tex-math></inline-formula> during a two-vehicle competition involving dynamic overtaking maneuvers on the Las Vegas Motor Speedway, a famous racetrack with turns banked up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$20^{\circ }$</tex-math></inline-formula> .

POWERbreathe® S-Index Test – guidelines and recommendations for practitioners

Abstract Study aim: POWERbreathe® S-Index Test is an accessible and functional evaluation of inspiratory muscle strength. The main purpose of this study is to present guidelines that allow to successfully apply the test in sports settings with high accuracy, robustness, and repeatability. Material and methods: Review of available literature and professional guidelines regarding traditional spirometry testing and POWERbreathe® trainers’ application was performed. The obtained information was summarized, analyzed, and interpreted to create POWERbreathe® S-Index Test guidelines and recommendations for practitioners. POWERbreathe® K4 and K5 (POWERbreathe International Ltd., Southam, UK) devices paired with Breathe-Link Live Feedback Software (POWERbreathe International Ltd., Southam, UK) were considered during the analysis and guidelines creation. Results: We recommend performing POWERbreathe® S-Index Test with 8 forceful and dynamic inspiratory maneuvers from residual volume to full inspiratory capacity, divided into 2–3 series of 2–3 maneuvers, in a standing position, after respiratory warm-up. Conclusion: POWERbreathe® S-Index Test may be a useful tool to measure functional inspiratory muscle strength in athletes. When performed with the presented guidelines, it can be successfully applied in sports settings with high accuracy, robustness, and repeatability.

Establishment of empirical formulae for hydrodynamic derivatives of submarine considering design parameters

The hydrodynamic derivatives are necessary for assessing the dynamic characteristics, such as dynamic stability and maneuverability which are crucial in evaluating navigation safety and operational efficiency. Hence, it is required to compute the hydrodynamic derivatives precisely. This study nominates the new empirical formulae for predicting the hydrodynamic derivatives of a submarine. The proposed empirical formulae are derived from hydrodynamic forces and moments which are measured using Computational Fluid Dynamic (CFD) approach. Because the BB2 generic submarine is designed with an appropriate geometry and outstanding features, especially directionally stability, so, it is designated to establish the empirical formulae. The design parameters that have a significant impact on the maneuverability of the BB2 submarine, such as the length-to-diameter ratio, sail position, and sail height, are altered to fit different types of submarines for various purposes. Then, hydrodynamic derivatives of each change factor of the design parameter are taken using the least square method and assessed in relationship with the design parameters through correlation analysis. The high correlation values determine the independent variables which are the design parameters to form the empirical formulae for each hydrodynamic derivative based on multiple regression analysis. The applicability of the established empirical formulae is confirmed by applying them to calculate the hydrodynamic derivatives of BB2 and 2000 tons submarines, and comparing the calculation with the available data. The high precision implies that the established empirical formulae can be used to predict the hydrodynamic derivatives of similar profile submarines to the BB2 and 2000 ton submarines, and they can be extended to submarines in general at the designing phase.

Robust Unscented Kalman Filter-Based Decentralized Multisensor Information Fusion for INS/GNSS/CNS Integration in Hypersonic Vehicle Navigation

INS/GNSS/CNS (inertial navigation system/global navigation satellite system/celestial navigation system) integration is a favourable navigation mode for hypersonic vehicles. However, since the measurements from GNSS and CNS are easily interfered during highly dynamic maneuvers, this integration is very difficult to achieve optimal navigation solution with existing information fusion techniques. This paper proposes a new method of decentralized multi-sensor information fusion based on robust UKF (unscented Kalman filter) for INS/GNSS/CNS integration to solve the above issue. Firstly, a fault detection-based robust UKF is established for local state estimation, in which a hypothesis test is constructed via the Mahalanobis distance of innovation to detect abnormal measurements in GNSS and CNS; and subsequently, a scalar factor is determined and further introduced into the innovation covariance to decrease the Kalman gain to improve the UKF robustness against abnormal measurements. Secondly, the traditional multi-sensor optimal data fusion technique is extended to nonlinear systems by use of unscented transformation in the framework of minimum variance estimation to fuse the local state estimations from INS/GNSS and INS/CNS subsystems. The proposed information fusion method can achieve the globally optimal fusion estimation results against abnormal measurements for hypersonic vehicle navigation with INS/GNSS/CNS integration. Semi-physical simulations and comparison analysis have validated the superior performance of the proposed method.

Space Noncooperative Target Trajectory Tracking Based on Maneuvering Parameter Estimation

The space noncooperative target maneuvering trajectory tracking is essential for the safety of the on-orbit spacecraft. For the noncooperative target, the maneuvering model is complex and changeable. Besides, the maneuvering dynamics model, the operation time, and the maneuvering frequency are previously unknown. It is difficult to achieve high-precision maneuvering trajectory tracking. In this paper, a novel real-time maneuvering trajectory tracking algorithm is developed, in which the maneuvering trajectory of the noncooperative target is discretized first, and then the differential algebra method is utilized to estimate the maneuvering parameter of the noncooperative target in the discretized time. Since the discretized period is very short, the maneuvering parameters of the target in the next discretized time are assumed to be the same as those in the previous discretized time, and the estimated maneuvering parameters are utilized to predict the target’s relative state in the next discretized time to achieve maneuvering trajectory tracking. Compared with the interactive multimodel method (IMM), the proposed method can estimate the maneuvering parameter of the noncooperative target in real time, which greatly reduces the tracking error caused by the mismatching of the target’s maneuvering model. In order to verify the effectiveness of the algorithm, a simulation of a noncooperative target’s maneuvering trajectory tracking is provided. The results demonstrated that the proposed method could track the noncooperative target maneuvering in real time, and the estimation accuracy was improved by about 93.07% compared with the IMM.

Implementation of Omnidirectional Movement on Rugby Robot

Robots in the KRAI competition (Indonesian ABU Robot Contest) are required to be able to maneuver and move well, efficiently and quickly in order to be able to carry out the task of picking up and kicking rugby balls. In order for the robot to move quickly and precisely, a wheel that can move dynamically is needed. The wheel used is the Omniwheel. This wheel has a small wheel located on the outer side of the main wheel, so that the movement of the rugby robot can run smoother when changing positions. With dynamic and efficient maneuvers and displacement of the rugby robot, the robot can move more agile and can stop in the desired position.

A Quadrotor With a Passively Reconfigurable Airframe for Hybrid Terrestrial Locomotion

Despite efforts to circumvent and alleviate the impact of a mid-flight collision, it remains extremely challenging to safeguard a multirotor vehicle when it operates in cluttered environments. In this work, we introduce a flying robot with the ability to roll through a gap narrower than its diameter to prevent a possible aerial collision entirely. The novelty of the proposed design lies in a simple passive mechanism that redirects the propelling thrust for the terrestrial operation without the need for extra actuators. As a result, the robot remains compact and lightweight. Furthermore, to overcome the underactuation associated with the passive structure, the transitions between flight and rolling are accomplished with a highly dynamic maneuver. In the experimental demonstration, the robot seamlessly switched between the aerial and terrestrial locomotion to safely negotiate a 10-cm opening.

Modelling the effect of aggressive driver behavior on longitudinal performance measures during car-following

Driving aggression is a major concern during car-following situations as it is closely associated with collision risk and crash severity. Despite the tendency of reckless driving actions and increased crash risk with the vehicle ahead, aggressive driver behavior remains unexplored. The present study aimed to investigate the effects of aggressive driver behavior (three driver categories: aggressive, moderately aggressive, and non-aggressive drivers) and drivers’ tendency to aggressive stimuli (due to lead vehicle (vehicle moving ahead) reckless driving) on car-following behavior. A sample of fifty-eight Indian drivers participated in this study. All the experiments were conducted using a driving simulator. The simulator design includes a lead vehicle dynamic maneuver with rapid accelerations and decelerations (at 1 m/s2, 1.5 m/s2, and 2 m/s2). Three longitudinal performance measures including speed variability (SPV) from LV, speed recovery time (SRCT), and time spent tailgating, were analyzed during LV acceleration stage using generalized linear models (GLM). Further, to assess collision avoidance behavior and crash risk, deceleration adjusting time (DAT) was analyzed during the LV sudden deceleration stage using Weibull Accelerated Failure Time (AFT) analysis. The findings indicate that due to their tendency to risk-raking behavior, aggressive drivers decreased their SPV and SRCT by 25 % and 18 %, respectively. The time spent tailgating increased by 107 % for aggressive drivers. The survival probabilities were decreased by 23.77 % for aggressive drivers at 3 sec DAT. The findings of the study can be used in car-following models to enhance the model performance, improve the reliability of simulation tools, and design interventions to improve safety (in automated driving).

Dynamic soaring as a means to exceed the solar wind speed

A technique by which a spacecraft can interact with flows of ionized gas in space (the solar wind or interstellar medium) in order to be accelerated to velocities greater than the flow velocity is explored. Inspired by the dynamic soaring maneuvers performed by sea birds and gliders in which differences in wind speed are exploited to gain velocity, in the proposed technique a lift-generating spacecraft circles between regions of the heliosphere that have different wind speeds, gaining energy in the process without the use of propellant and only modest onboard power requirements. In the simplest analysis, the spacecraft motion can be modeled as a series of elastic collisions between regions of the medium moving at different speeds. More detailed models of the spacecraft trajectory are developed to predict the potential velocity gains and the maximum velocity that may be achieved in terms of the lift-to-drag ratio of the vehicle. A lift-generating mechanism is proposed in which power is extracted from the flow over the vehicle in the flight direction and then used to accelerate the surrounding medium in the transverse direction, generating lift (i.e., a force perpendicular to the flow). Large values of lift-to-drag ratio are shown to be possible in the case where a small transverse velocity is imparted over a large area of interaction. The requirement for a large interaction area in the extremely low density of the heliosphere precludes the use of a physical wing, but the use of plasma waves generated by a compact, directional antenna to impart momentum on the surrounding medium is feasible, with the excitation of R-waves, X-waves, Alfven waves, and magnetosonic waves appearing as promising candidates. A conceptual mission is defined in which dynamic soaring is performed on the termination shock of the heliosphere, enabling a spacecraft to reach speeds approaching 2% ofcwithin two and a half years of launch without the expenditure of propellant. The technique may comprise the first stage for a multistage mission to achieve true interstellar flight to other solar systems.

Orbital hopping maneuvers with two Astrobee free-flyers: Ground and flight experiments.

Dynamic hopping maneuvers using mechanical actuation are proposed as a method of locomotion for free-flyer vehicles near or on large space structures. Such maneuvers are of interest for applications related to proximity maneuvers, observation, cargo carrying, fabrication, and sensor data collection. This study describes a set of dynamic hopping maneuver experiments performed using two Astrobees. Both vehicles were made to initially grasp onto a common free-floating handrail. From this initial condition, the active Astrobee launched itself using mechanical actuation of its robotic arm manipulator. The results are presented from the ground and flight experimental sessions completed at the Spacecraft Robotics Laboratory of the Naval Postgraduate School, the Intelligent Robotics Group facility at NASA Ames Research Center, and hopping maneuvers aboard the International Space Station. Overall, this study demonstrates that locomotion through mechanical actuation could successfully launch a free-flyer vehicle in an initial desired trajectory from another object of similar size and mass.

System identification of Vessel Manoeuvring Models

Identifying the ship’s maneuvering dynamics can build models for ship maneuverability predictions with a wide range of useful applications. A majority of the publications in this field are based on simulated data. In this paper model test data is used. The identification process can be decomposed into finding a suitable manoeuvring model for the hydrodynamic forces and to correctly handle errors from the measurement noise. A parameter estimation is proposed to identify the hydrodynamic derivatives. The most suitable manoeuvring model is found using the parameter estimation with cross-validation on a set of competing manoeuvring models. The parameter estimation uses inverse dynamics regression and Extended Kalman filter (EKF) with a Rauch Tung Striebel (RTS) smoother. Two case study vessels, wPCC and KVLCC2, with very different maneuverability characteristics are used to demonstrate and validate the proposed method. Turning circle predictions with the robust manoeuvring models, trained on zigzag model tests, show good agreement with the corresponding model test results for both ships.

The value of dynamic MRI in cervical spondylotic myelopathy: About 24 cases.

Dynamic magnetic resonance imaging (MRI) of the cervical spine is extremely useful in assessing pathological changes at the spinal cord, vertebrae, discs, ligaments and facet joints. We attempted to document the radiological changes that the cervical spine undergoes during dynamic maneuvers and the effects of Dynamic MRI in management of cervical myelopathy, emphasizing on the changes in treatment protocol effected by the new findings discovered. Our work is based on 24 consecutive patients with cervical spondylotic myelopathy had cervical MR imaging in neutral position, in flexion and extension of the cervical spine between January 2021 and December 2021. The result found the mean age was 57.9 years (range 26-85 years). Among these 24 patients, there were 11 males and 13 females. Total number of levels of compression were 47 and the additional levels of involvement were 17. Additional levels of compression were noted in 12 patients, among these 17 new levels, 7 were in the posterior and 10 in the anterior. The most affected level was C5C6 with 16 cases. All additional levels of compression were noted in extension; Reduction of the cervical canal was observed in 20 patients only in extension. In the bending sequences we have noticed an increase of the canal diameter in 3 patients. The location of the compression is in 15 cases anterior, 2 cases posterior and 5 cases are mixed anterior and posterior Surgery was considered in 17 patients. Anterior procedures were 11 (ACDF/corpectomy and fusion) and Posterior surgeries were 6 (laminoplasty/laminectomy), and. The rest of the patients did not require surgery and was conservatively treated. A change of the signal was found in 3 patients during the acquisition in extension position a. Most studies have shown a reduction of the root canal with an increase of the compression level, which was the case in our study. MRI is a useful tool for diagnosis of CM, it does not give an exact idea as to which is the offending level in a multilevel compression that requires surgery. Even the approach and procedure cannot be decided on a static examination and hence are subject to significant interpractitioner the role of extension MRI in determining cervical compression levels. Thus, dynamic cervical spine MRI should be an important investigation before we decide to write off surgical treatment in patients with cervical myelopathy and cord signal changes without definitive compression on static MRI. Flexion and extension MRI is an important tool for decision making and planning appropriate management in cervical compressive myelopathy.

A time-series turbofan engine successive fault diagnosis under both steady-state and dynamic conditions

In recent years there has been a growing interest in gas turbine fault diagnosis, especially under dynamic conditions, due to the evolving operating profile of gas turbines and the need to deploy computationally efficient and high-precision diagnostic solutions in real-time. One of the main challenges of fault diagnosis in real-time is the power imbalance between the compressor and turbine that occurs during transient operation. In addition, the heat soakage phenomenon characterizing the transient conditions has a substantial impact on the accuracy of the diagnosis. Finally, any sudden failure that might happen during transient operating conditions creates an additional challenge to fault diagnostics. The present study proposes a gas turbine diagnostic approach based on time-series measurements encapsulating steady-state and transient operating conditions. Specifically, the introduced novel approach is capable of quantifying the surplus/deficit of the power between the compressor and the turbine by utilizing the time-series data representing the observed deviations in the shaft rotational speed in order to determine the power balance in the shaft. The maximum diagnostic errors for constant fault and sudden failure are less than 0.006% during the dynamic maneuver. The results demonstrate and illustrate that the proposed method could effectively and accurately diagnose the severity of aero-engine faults at both steady-state and transient conditions. Therefore, this study has great potential for gas turbine practitioners since the diagnosis under transient conditions in real-time can enhance the capability of engine online condition monitoring and improve the condition-based maintenance of gas turbine assets.

Turn and zigzag manoeuvres of Delft catamaran 372 using CFD-based system simulation method

Special demands in marine applications such as large capacities in transportation and fast deployment in military operations have brought multihull concepts forward. Open deck areas, high stability characteristics, and a wide range of operating speeds are some of the strong sides of these vessels. The fact that few studies have been done on manoeuvring performance predictions of these types of ships has been the main source of motivation in conducting this study. A fast multihull form, Delft Catamaran 372 (DC372), has been selected for computational fluid dynamics (CFD)-based system simulation application. CFD method has been subjected to a verification and validation (V&V) process using the latest solution verification techniques and available comparison data in the literature. The computerized planar motion mechanism (CPMM) approach has been applied to determine all the necessary hydrodynamic derivatives stated in Abkowitz's manoeuvring model. A new approach to analysis of manoeuvring performance of multihull vessels, discrete study of hull components (DSHC), has been introduced for the interpretation of manoeuvring coefficients. The dynamic manoeuvre system simulator (DynaMaSS) in which a waterjet and conventional steering/propulsion units (SPUs) are implemented, has been presented for the 20-degree turning circle (TC20) and 20/20 zigzag (ZZ20) manoeuvre simulations of DC372. The manoeuvring coefficients of DC372 have been determined at a satisfactory level by the CFD method. Successful results and solution strategies have been presented for DC372.

Ultrasound-guided joint interventions of the lower extremity.

The purpose of this article is to better understand the role ultrasound plays in lower extremity joint interventions. Ultrasound is an important and reliable tool diagnostically and therapeutically. Real-time feedback, lack of ionizing radiation, and dynamic maneuverability make ultrasound an important tool in the proceduralist's armament. This article will touch upon the important anatomic considerations, clinical indications, and technical step-by-step details for lower extremity ultrasound interventions. Specifically, we will look at interventions involving the hip, knee, ankle, and foot. In addition, this article will discuss the roles corticosteroid and platelet-rich plasma may play in certain interventions.

Morphologically Adaptive Crash Landing on a Wall: Soft‐Bodied Models of Gliding Geckos with Varying Material Stiffnesses

Landing on vertical surfaces in challenging environments is a critical ability for multimodal robots—it allows the robot to hold position above the ground without expending energy to hover. Asian flat‐tailed geckos (Hemidactylus platyurus) are observed to glide and perch on vertical surfaces by relying on their tail and body morphology, potentially reducing the control effort to perch. This novel perching mechanism using a bioinspired physical model is discussed and its tail and body parameters to determine their influence on perching success and the kinematics of the gecko's dynamic landing maneuver are adjusted. Perching performance is evaluated by changing the model's torso and tail stiffness. Combining a compliant torso and stiff tail enables the model to passively perch on a vertical substrate with a success rate &gt;90%, compared with ≈10% without a tail attached. A compliant torso is necessary to absorb the in‐flight kinetic energy and accommodate the uncertainties in approach conditions. Similar to the gecko's perching strategy, the stiff tail pushes against the substrate, preventing the model from falling backward head over heels. These findings highlight the critical role of tail and material stiffness for perching and provide a simplified mechanism to impart perching capabilities in robots.