Launch Angle Research Articles

Simulation of Launch Pad Atomization for Military Weapon System

This study aims to optimize three critical parameters (inclination angle, hook lifting, and sparking) for a missile launching system by combining precise mathematical methods, IoT concepts, and advanced sensor technologies. The system uses an Inertial Navigation System (INS) in conjunction with gyro and proximity sensors to ensure accurate target interception by carefully determining the optimal launch angle. The Internet of Things concept is integrated effortlessly, with a clever coordinating WiFi networking, weight estimation, and sensor data processing for real-time cloud data flow. Security protocols protect the integrity of the data, and a reliable power supply system guarantees reliable operation. The project incorporates both Hot Start and Cold Start functionalities, enabling dependable launches and prompt adaptations to dynamic changes. Flexible igniting mechanisms such as Chemical, Electrical, and Electro-Chemical systems are available, and reliable and secure missile launches are prioritized with safety features like Spark Damping Inner Tube Coating and Moisture-Resistant igniting. All things considered, this project prioritizes security, dependability, and adaptability while addressing critical elements required for a sophisticated and efficient missile launching system.

Structural design and dynamic characteristic analysis of adjustable badminton serving machine

System dynamics serves as a crucial foundation for evaluating the performance of mechanical auxiliary equipment. To enhance the stability and reliability of the badminton launch process, structural design and dynamic analysis were conducted on a mode-adjustable, precise control badminton serving mechanism. The combination of eccentric crank-slider mechanism, stretched springs, and electromagnets was used in mechanical structures, which could effectively effectively improve the smoothness of the badminton in the launching process. The virtual prototype of badminton serving machine was established and imported into ADAMS for dynamic simulation analysis, verifying the correctness of the serving and retrieving mechanisms. Using the aerodynamic equations, the trajectory of badminton movement under different working parameters was simulated and analyzed. The dynamic analysis results show that the design of the launching and catching mechanisms is scientific and effective. The launch angle and initial velocity are the key factors that determine the trajectory of the badminton.

Intelligent System for Artillery Mount Autonomous Guidance And Firing Adjustment

The article presents mathematical models, numerical algorithms and a software package for an intelligent system for artillery mount autonomous guidance and adjustment of firing. The software package includes the following components: a module for solving the direct problem of external ballistics, a neural network training module, and a firing guidance and adjustment module. The first module is designed to form a database of computational experiments by repeatedly solving the direct problem of external ballistics under varying firing conditions. In the second module, a neural network is trained to solve the inverse problem of external ballistics using the database generated from computational experiments. The third module implements algorithms for calculating the artillery mount launching angles on a target using a trained neural network and calculating corrections to launching angles based on data on the projectile impact point deviation from the target. Having received data on the artillery mount readiness to fire, the coordinates of the target position and projectile’s impact point received from a digital observer, the software package calculates the necessary launching angles or corrections to them. Launching angles are transferred via text files to the control system of the artillery mount drives, then a shot is fired and the conditions for hitting the target are assessed. The algorithm is then repeated for the next shot or new target. Testing of the developed algorithms for autonomous guidance and shooting correction was carried out using modeling of external ballistics processes in the software package, as well as carrying out experimental testing on a working simulation device of an artillery mount. The developed software package allows visualization of the obtained results and saving the history of the performed operations.

Multi-objective Topology Optimization Design for a Certain Launcher Bracket

To achieve weight reduction and enhance the firing accuracy of a specific type of launch device, the bracket was selected as the optimization subject for multi-objective topology optimization. Single-objective optimization often overlooks other influencing factors. To address the limitations of single-objective optimization, this study adopts the variable density method from the SIMP approach and proposes a multi-objective topology optimization based on compromise programming. This study, through multi-objective topology optimization of the bracket, obtained an optimized topology structure that maximizes static stiffness and the dynamic low-order natural frequencies of the launch device bracket at launch angles of 0°, 53°, and 85°, with an azimuth angle of 0°. Finally, the obtained topology structure was validated using finite element software. The design method presented in this paper not only enhanced the stiffness of the bracket structure for such launch devices and increased the first two natural frequencies of the bracket but also achieved weight reduction. The optimization design process also provides a reference for other mechanical structures.

Mechanisms of speed-accuracy trade-off in tennis topspin forehand of college players

ABSTRACT This study aimed to elucidate the mechanisms underlying the speed-accuracy relationship in a tennis topspin single-handed forehand groundstroke. Groundstrokes at three different speeds by nine college players were captured, with the variability of the ball landing position evaluated as indices of accuracy. Variabilities of ball launch variables (speed, launch angle, spin, etc.) and conversion ratios from these variabilities to the variability of the ball landing position were quantified. These variabilities and their conversion ratios could be influenced by different efforts exerted to generate ball speeds and different ball trajectories required to hit a target at each speed, respectively. The speed-accuracy trade-off was observed only in the hitting direction. While the variability of the spin axis increased, it had minimal influence on the ball landing position. Conversely, the conversion ratio in the hitting direction of the velocity elevation angle significantly increased, while its variability remained unchanged. Consequently, the geometrical requirements of ball trajectories can be responsible for the speed-accuracy trade-off. Therefore, even skilled players capable of maintaining consistent ball launch variables regardless of the shot speed should deliberately choose a moderately slower ball speed to avoid an inevitable increase in the variability of the ball landing position due to geometrical requirements.

Observation of off-axis solitary waves propagating along a specific trajectory in photorefractive crystals.

We report the propagation dynamics of swallowtail beams (SBs) within a photorefractive crystal. In the nonlinear regime, the self-accelerating and secondary self-focusing features of the swallowtail beams are influenced, and a solitary wave is generated. The main lobe energy of the swallowtail beams is guided to a specific inclined trajectory, leading to a stable solitary wave, and we control the output position of the solitary wave by changing the launch angle. Our results are supported by the corresponding experiments. In addition, we demonstrate that a Gaussian beam can be effectively guided in swallowtail optical waveguide structures. Our research represents an interesting interaction between the swallowtail beams and nonlinear medium, which may find potential applications in photonic integrated devices and optical information transmission.

Research on adaptive penetration characteristics of space harpoon based on aluminum honeycomb buffer

To address the issues of high impact and limited adaptability in capturing space debris with space harpoons, a novel harpoon capture device based on aluminum honeycomb buffering was proposed. The issue of excessive impact force for harpoons could be effectively addressed by the excellent energy-absorbing characteristics of aluminum honeycomb. A simulation model was established to analyze the penetration of space harpoons into aluminum alloy target plates using Johnson-Cook’s dynamic constitutive model and fracture failure criteria. Ground experiments were conducted to validate the correctness of the simulation model. The impact of aluminum honeycomb was investigated by analyzing the simulation results of harpoons with and without aluminum honeycomb. With the introduction of aluminum honeycomb as a buffering component, the rebound velocity of the harpoon decreased by 76.2 %, and the impact force reduced by 78.6 %. Then the model was used to study the influence of different launching angles and different targets on the penetration characteristics of the space harpoon. The research findings indicate that space harpoons could successfully penetrate and capture aluminum alloy targets at a launch velocity of 53.1 m/s to 58.5 m/s, as determined through ground experiments and simulation analysis. The error in the crushing height of the aluminum honeycomb was found to be 2.19 %, while the error in the harpoon penetration depth was 9.02 %. Moreover, within a launch angle error of 10°, space harpoons also demonstrate the capability for adaptive capture of both aluminum alloy plates and aluminum honeycomb sandwich panels, with average correction capabilities of 92.5 % and 95.5 %. In conclusion, the analysis of the adaptive penetration characteristics of space harpoons provides a solid theoretical foundation and technical support for the design of harpoon capture systems.

Shooting stars on schedule: synchronising re-entry of particles launched from a satellite

The ALE-3 mission plans to create artificial ‘shooting stars’ in the upper atmosphere by launching pellets sequentially from a satellite in low Earth orbit. How does one arrange for all pellets to re-enter over the intended location simultaneously? Starting with conservation of energy and angular momentum, I derive a version of Kepler’s equation that gives time as a function of radial distance in an orbit, which can be used to find the transfer time from the pellet’s ejection to its re-entry as a function of its launch velocity. I show that for a given pellet ejection speed, there is a launch angle from the satellite that results in the fastest transfer time. I use these results to determine the pellets’ launch times and velocities for simultaneous arrival at a desired re-entry point. These results can be applied to de-orbiting any set of objects launched from a satellite, and use concepts that can be covered in an advanced undergraduate course in physics or aerospace engineering.

Dual-doppler signal mixing laser doppler velocimeter

In order to reduce the requirement of system bandwidth of Laser Doppler Velocimeter (LDV), a Dual-Doppler signal mixing LDV is proposed in this paper. By transmitting two beams to the moving surface, two Doppler signals are acquired and subsequently mixed to obtain a difference frequency signal. The measured speed can be calculated based on the frequency of this difference frequency signal. This novel structure significantly reduces the bandwidth requirements on the system, which can be further diminished by minimizing the angle between the two beams of the emitted light. Moreover, it exhibits enhanced robustness against variations in launch angle and enables defocusing measurements.

Visual Perception and Multimodal Control: A Novel Approach to Designing an Intelligent Badminton Serving Device

Addressing the current issue of limited control methods for badminton serving devices, this paper proposes a vision-based multimodal control system and method for badminton serving. The system integrates computer vision recognition technology with traditional control methods for badminton serving devices. By installing vision capture devices on the serving device, the system identifies various human body postures. Based on the content of posture information, corresponding control signals are sent to adjust parameters such as launch angle and speed, enabling multiple modes of serving. Firstly, the hardware design for the badminton serving device is presented, including the design of the actuator module through 3D modeling. Simultaneously, an embedded development board circuit is designed to meet the requirements of multimodal control. Secondly, in the aspect of visual perception for human body recognition, an improved BlazePose candidate region posture recognition algorithm is proposed based on existing posture recognition algorithms. Furthermore, mappings between posture information and hand information are established to facilitate parameter conversion for the serving device under different postures. Finally, extensive experiments validate the feasibility and stability of the developed system and method.

Shoulder Movement-Centered Measurement and Estimation Scheme for Underarm-Throwing Motions.

Underarm throwing motions are crucial in various sports, including boccia. Unlike healthy players, people with profound weakness, spasticity, athetosis, or deformity in the upper limbs may struggle or find it difficult to control their hands to hold or release a ball using their fingers at the proper timing. To help them, our study aims to understand underarm throwing motions. We start by defining the throwing intention in terms of the launch angle of a ball, which goes hand-in-hand with the timing for releasing the ball. Then, an appropriate part of the body is determined in order to estimate ball-throwing intention based on the swinging motion. Furthermore, the geometric relationship between the movements of the body part and the release angle is investigated by involving multiple subjects. Based on the confirmed correlation, a calibration-and-estimation model that considers individual differences is proposed. The proposed model consists of calibration and estimation modules. To begin, as the calibration module is performed, individual prediction states for each subject are updated online. Then, in the estimation module, the throwing intention is estimated employing the updated prediction. To verify the effectiveness of the model, extensive experiments were conducted with seven subjects. In detail, two evaluation directions were set: (1) how many balls need to be thrown in advance to achieve sufficient accuracy; and (2) whether the model can reach sufficient accuracy despite individual differences. From the evaluation tests, by throwing 20 balls in advance, the model could account for individual differences in the throwing estimation. Consequently, the effectiveness of the model was confirmed when focusing on the movements of the shoulder in the human body during underarm throwing. In the near future, we expect the model to expand the means of supporting disabled people with ball-throwing disabilities.

SYSTEM FOR AUTOMATED CALCULATION OF PARAMETERS OF THE STAGE OF LAUNCHING AN UNMANNED AERIAL VEHICLE FROM A CATAPULT-TYPE LAUNCHER

This analysis focuses on the various stages involved in launching unmanned aerial vehicles (UAV) and highlights the key considerations that must be taken into account during these stages. When launching UAV in rugged terrain without a proper runway, alternative launch mechanisms, such as a catapult-type launcher, must be developed. The use of a catapult launcher offers several advantages, including the ability to launch in confined spaces and a quick preparation time. However, the development of a launcher is a complex process that requires a comprehensive approach, involving sophisticated engineering solutions to calculate launch parameters and the flight path of the UAV. Throughout the launch process, the UAV progresses through different stages, starting from the ignition of the starting engine until it reaches the desired height and speed. It is crucial to consider various parameters that influence the trajectory of the UAV during the launch phase. The authors determined the influence of the characteristics of the engines and launcher on the trajectory of the UAV and formulated a mathematical model for calculating the speed and coordinates of movement, which have a significant impact on the flight path. A system for automated calculation of the parameters of the first stage of launching a UAV from a catapult-type launcher is proposed, this system will reduce the time for product development, as well as reduce the influence of the human factor, which will lead to a decrease in the error in calculations. To analyze the starting characteristics of the product, a catapult model was chosen, which consists of a guide, a carriage and a UAV with a starting engine. The influence of the mass of the product, the launch angle and the distribution of external forces acting on the product are taken into account, which leads to the calculation of the initial values for further design. The result of the application of the system is to obtain the parameters of the speed of movement and the position of the flying object in tabular and graphical forms

Golfers' Performance Is Improved More by Combining Foam Rolling and Dynamic Stretch to the Lead Hip Than Practice Golf Swinging.

Hamada, Y, Akasaka, K, Otsudo, T, Sawada, Y, Hattori, H, Kikuchi, Y, and Hall, T. Golfers' performance is improved more by combining foam rolling and dynamic stretch to the lead hip than practice golf swinging. J Strength Cond Res 38(7): e391-e397, 2024-Warming up is considered effective in improving performance and preventing injury. Despite this, there have been few studies investigating warm-up programs in golf and whether specific factors contribute to improved performance. The purpose of this study was to examine the immediate effects of combined foam rolling and dynamic stretch (FR + DS) to the lead hip on golf swing performance, hip range of motion (ROM), and muscle strength in amateur golfers using a randomized crossover design. The study sample comprised 22 men (mean ± SD ; age, 32.6 ± 8.5 years, body mass index (BMI), 23.4 ± 2.7 kg·m -2 ). Subjects were assigned to receive either FR + DS or repetitive golf swing practice (SW) before crossing over to the other intervention for another day. Measurements included golf swing performance (ball speed, club head speed, flight distance ["carry"], spin rate, and launch angle), hip internal rotation (IR), and external rotation (ER) ROM, as well as hip IR and ER muscle strength. Comparisons between groups were made before and after each intervention. For golf swing performance, FR + DS improved "carry" significantly more than SW ( p < 0.05). No significant differences in golf swing performance other than "carry" were found. In addition, IR ROM and IR muscle strength of the lead hip were significantly increased in the FR + DS group ( p < 0.05). FR + DS has effects on improving lead hip IR ROM and IR muscle strength, which may facilitate golfers' swing and "carry." FR + DS shows promise as a warm-up method for amateur golfers who want to improve golf performance.

Classifying batted ball outcomes from Division I collegiate baseball players

ABSTRACT Modern technology challenges anecdotal beliefs on baseball performance. The study’s purpose examines these beliefs by classifying batted ball outcomes. Three categories of independent variables (anthropometry, in-game situation, technique-based), from 1,922 batted ball outcomes produced by 230 players, were used to classify the likelihood of hits during 2021 college baseball games. Anthropometry included player’s heights and weights. In-game situation entailed batter side, same side, ahead count, and pitch type. Technique-based variables measured by TrackMan radar included exit speed (ExSp), launch angle (LA), batted ball distance (BBD), and hang time (HT). Binary logistic regression analysis was performed with batted ball outcome as the dependent variable. Independent variables provided a good fit (χ2 (10) = 522.358, p < 0.01) and correctly classified nearly three-fourths of outcomes. Height (β = 0.030, p < 0.05), ExSp (β = 0.023, p < 0.05), LA (β = 0.028, p < 0.01), and BBD (β = 0.067, p < 0.01) each had significant positive associations, yet HT (β = –1.661, p < 0.01) had a significant negative association, with batted ball outcomes. TrackMan provided four significant independent variables. Anthropometry’s contribution to batting outcome was modest, while in-game situation’s impact was non-significant; results contradict anecdotal beliefs of their importance.

Trajectory of a golf ball on a sloping green

Calculations are presented on the trajectory of a golf ball that rolls across the inclined surface of a golf green. The ball follows a curved path and comes to a stop at a point displaced at an angle to the initial launch direction. It is shown that the displaced angle is independent of the launch speed but depends on the launch angle and the ratio of the incline angle to the coefficient of rolling friction. The stopping distance is proportional to the launch speed squared. A simple experiment is described to check the calculations.

Backspin in Ruellia ciliatiflora does not maximize seed dispersal range, but provides moderate dispersal range thatisrobust to launch conditions.

Ruellia ciliatiflora is a perennial herb whose fruits explosively dehisce, launching their thin disc-like seeds over 6 m with a backspin up to 1660 Hz. Whileithas been previously shown that the backspin launch orientation minimizes the aerodynamic drag experienced by the seeds, it is not immediately obvious whether backspin is also the range-maximizing launch orientation. Here the three-dimensional equation of motion of a thin, spinning disc flying through a fluid medium was derived and solved numerically to simulate the flight of seeds of R. ciliatiflora under different launch conditions. Simulations of seed flights reveal that the range-maximizing launch orientation lies between sidespin and topspin, far from the backspin that is observed in nature. While this range-maximizing orientation results in dispersal ranges of nearly 10 m, the precise orientation is highly sensitive to other launch parameters, chiefly spin rate and launch angle. By contrast, backspin, which yields moderate dispersal ranges about 60% of the range-maximizing orientation, is robust to perturbations in launch parameters that the plant cannot precisely control.

What else can we do with auxiliary parameters in ray tracing? How about back projection for localization?

Auxiliary parameters describing variations in ray path geometry with respect to initial launch angles have been leveraged in computing the Jacobian determinant needed to solve the transport equation as well as to build a Levenberg–Marquardt algorithm for identification of source-receiver paths (termed eigenrays) in a 3D inhomogeneous moving atmosphere. Building on these applications, recent investigations have demonstrated that these parameters can be computed along back projected ray paths from infrasonic detections to improve Bayesian localization capabilities. An overview of the auxiliary parameters as introduced in previous work will be provided along with a summary of current localization development. Example applications of the method will be presented and compared with existing Bayesian infrasonic localization methods using more general propagation models.

The effects of different iron shaft weights on golf swing performance.

This study examined the effects of three 7-iron shaft weights on golf swing performance among golfers of varying skill levels. The study included 10 low-handicap (LH; 4.3 ± 2.4) and 10 high-handicap (HH; 29.1 ± 5.4) right-handed golfers as participants. The participants were randomly assigned 7-iron clubs with shaft weights categorized as light (77g), medium (98g), or heavy (114g), and they performed test shots. Kinematic data were captured using a motion analysis system with nine infra-red high speed cameras; a force platform connected to this system was used to record weight transfer patterns. Performance variables were assessed using a FlightScope launch monitor. A two-way mixed-design analysis of variance was used to determine the significance of the performance differences among both participant groups and golf shaft weights. The results indicated that during the backswing, the LH group exhibited significantly greater maximum rightward upper torso rotation, maximum X-factor, and maximum right wrist hinge rotation than did the HH group. During the downswing, the LH group exhibited significantly greater maximum upper torso angular velocity and maximum right wrist angular velocity than did the HH group. Moreover, the LH group produced significantly higher ball speeds, longer shot distances, and lower launch angles than did the HH group. The shaft weight neither greatly altered the golf swing nor displaced the center of gravity of the golfers. The lighter shafts were observed to facilitate faster clubhead speeds and initial ball velocities, thereby resulting in longer shot distances, especially among LH golfers. Although significant differences in swing mechanics and performance exist between HH and LH golfers, lighter shafts can contribute to increased shot distances for all golfers.

Assessment of the throwing effect of material fragments resulting from the detonation of explosive materials

The modelling of the throw effect of material fragments following the detonation of explosive materials with a harmful effect on the human component and/or nearby industrial/civil targets is based on the quantification of the impact of the throwing speed and mass of the material fragments. Models developed to generate trajectory calculations for ranges of mass, launch angles and launch velocity based on Monte Carlo simulations are sensitive to the predetermined ranges assigned to each trajectory variable, requiring long time intervals to run the simulations at the time of analysis and IT resources to match. Following the production of an explosion-type event, thousands of individual fragments characterized by their own mass and velocity parameters can be generated, resulting individual energy values that can be taken into account in a quantitative risk assessment, by grouping them into ten distinct classes, thus: Class 1st represents fragments with the highest kinetic energy and/or mass, and class 10th represents fragments with the lowest kinetic energy and/or mass. The paper will highlight the ten distinct classes of the kinetic energy parameter, with the maximum, average and minimum values for each class, as well as the average mass for each detached fragment associated with the energy classes.

Research on Simulation Approximate Solution Strategy for Complex Kinematic Models

Abstract In order to meet the needs of military, road construction, multimedia industry and other aspects, UAVs are gradually given more functions. As the basic function of UAV applications, the fixed-point delivery problem model has higher and higher accuracy requirements. However, in the actual scene, the UAV delivery problem is affected by the interaction of various factors such as flight height, air resistance, and dive angle, which makes it difficult to achieve high stability and high hit accuracy. This paper will analyze the complex motion model based on the fixed-point delivery of explosives by UAV, study the relationship between the stability of UAV delivery and the hit accuracy, and analyze the influence of relevant parameters on the problem by using modeling. In this paper, a multivariate nonlinear continuous time change model is proposed, and a continuous time slice discretization idea operation model is introduced to approximate the time slice splitting inside the UAV launch motion. Secondly, the design quantified evaluation index reaction the initial velocity of the explosive, the launch Angle, the height off the ground and other parameters to analyze the model. Finally, the best scheduling strategy is obtained and verified by using the idea of variable traversal and trial- and-error simulation. The experimental results show that the variation of UAV flying height, speed, depression and other interference factors is consistent with the prediction of score and hit accuracy, according to the environment setting of this model, when the UAV is 300 meters above the ground and 290 meters away from the target horizontal position, the delivery speed is 250m/s, and the pitch angle is about 27°, the fixed-point delivery of explosives is the best strategy.