scholarly journals Flight Stability Analysis of a Symmetrically-Structured Quadcopter Based on Thrust Data Logger Information

Symmetry ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 291 ◽  
Author(s):  
Endrowednes Kuantama ◽  
Ioan Tarca ◽  
Simona Dzitac ◽  
Ioan Dzitac ◽  
Radu Tarca
Keyword(s):  
Flight Control ◽  
Data Retrieval ◽  
Time Signal ◽  
Data Logger ◽  
Rotational Angle ◽  
Flight Stability ◽  
Axis Position ◽  
Parallel Axis ◽  
The Stability ◽  
Speed Adjustment

Quadcopter flight stability is achieved when all of the rotors–propellers generate equal thrust in hover and throttle mode. It requires a control system algorithm for rotor speed adjustment, which is related with the translational vector and rotational angle. Even with an identical propeller and speed, the thrusts generated are not necessarily equal on all rotors–propellers. Therefore, this study focuses on developing a data logger to measure thrust and to assist in flight control on a symmetrically-structured quadcopter. It is developed with a four load cells sensor with two-axis characterizations and is able to perform real-time signal processing. The process includes speed adjustment for each rotor, trim calibration, and a proportional integral derivative (PID) control tuning system. In the data retrieval process, a quadcopter was attached with data logger system in a parallel axis position. Various speeds between 1200 rpm to 4080 rpm in throttle mode were analyzed to determine the stability of the resulting thrust. Adjustment result showed that the thrust differences between the rotors were less than 0.5 N. The data logger showed the consistency of the thrust value and was proved by repeated experiments with 118 s of sampling time for the same quadcopter control condition. Finally, the quadcopter flight stability as the result of tuning process by the thrust data logger was validated by the flight controller data.

Distal Fibular Length Needed for Ankle Stability

2006 ◽  
Vol 27 (3) ◽  
pp. 185-189 ◽  
Author(s):  
Eiichi Uchiyama ◽  
Daisuke Suzuki ◽  
Hideji Kura ◽  
Toshihiko Yamashita ◽  
Gen Murakami
Keyword(s):  
Ankle Joint ◽  
External Rotation ◽  
Traction Force ◽  
Distal Fibula ◽  
Rotational Angle ◽  
Clear Cut ◽  
Long Term Stability ◽  
Ankle Stability ◽  
Fresh Frozen ◽  
The Stability

Background: The fibula is commonly used for bone grafts. Previous clinical and biomechanical studies have suggested that the length of the residual portion of the distal part of the fibula has an important effect on the long-term stability of the ankle joint. However, we cannot find clear-cut guidelines for the amount of bone that can be harvested safely. Methods: Using six normal fresh-frozen cadaver legs, motions of the tibia, talus and calcaneus were measured. The fibula was cut sequentially 3 cm from the proximal tip of the fibula and distally 10 cm, 6 cm, and 4 cm from the distal tip of the lateral malleolus. The angular motion of each bone was measured while a medial and lateral traction force of 19.6 N was applied to the proximal tibia. Angles of the tibia, talus, and calcaneus were measured. Results: Sequential resection of the fibula increased the inversion angles of the ankle joint. The proximal 3-cm cut increased the inversion angle from 42.1 ± 6.2 degrees to 49.6 ± 3.6 degrees, and the distal 4-cm cut increased the angle from 57.6 ± 6.6 degrees to 67.4 ± 5.9 degrees. The rotational angles were almost constant with sequential resections of the fibula; however, the distal 4-cm cut increased the rotational angle from 11.3 ± 25.1 degrees to 78.7 ± 37.5 degrees. Conclusions: The whole fibula including the head is essential for the stability of the ankle joint complex, and the distal fibula is responsible for stabilizing the ankle mortise during external rotation and inversion. We recommend fixation of the syndesmosis or bracing to prevent ankle joint instability with rotation of the talus in the mortise, especially when the distal fibula is shortened 6 cm or more.

Sensitivity Analysis of Blade Mode Shape on Flutter of Two-Dimensional Turbine Blade Sections

2000 ◽  
Author(s):  
Olga V. Tchernycheva ◽  
Sébastien Regard ◽  
François Moyroud ◽  
Torsten H. Fransson
Keyword(s):  
Experimental Data ◽  
Turbine Blade ◽  
Mode Shape ◽  
Numerical Models ◽  
Suction Surface ◽  
Flow Models ◽  
Reduced Frequency ◽  
Stability Maps ◽  
Axis Position ◽  
The Stability

A parametric study on the flutter stability of a turbine cascade as a function of the torsion axis position, the bending direction and the reduced frequency is presented. In this process two different unsteady flow models are used in order to minimize the uncertainties of numerical modeling on the physical conclusions of the study. Comparisons are performed against available experimental data. It was found that the comparison of the global aerodynamic damping between numerical results and experimental data was reasonably good. It was observed that the stability was more sensitive to changes in the mode shape than in the reduced frequency. Comparisons of the local unsteady pressures showed similar tendencies for the numerical models and the experimental data, while discrepancies on the blade suction surface between the models were observed around the trailing edge for the subsonic flow and close to shock location for the transonic flow. The results indicated interesting agreement of the mode shape stability maps with results obtained on a largely different low-pressure turbine blade.

PID Control Based Missile Sub-Channel Simulation

2012 ◽  
Vol 433-440 ◽  
pp. 7011-7016 ◽  
Author(s):  
Chao Bo Chen ◽  
Bing Liu ◽  
Ning He ◽  
Song Gao ◽  
Quan Pan
Keyword(s):  
Control System ◽  
Real Time ◽  
Flight Control ◽  
Pid Control ◽  
Pid Controller ◽  
Channel Model ◽  
Control Method ◽  
Flight Control System ◽  
Aerodynamic Control ◽  
The Stability

The accuracy and real-time of modern missile flight control system of traditional aerodynamic can not be satisfied. In this paper a new method is presented to improve the accuracy and real-time of missiles under this condition. First of all, a missile sub-channel model of the dynamic equations and steering gear is established, then based on the established model, using PID controller to control steering gear and three channels of missile pitch, yaw, roll respectively which is called missile sub-channel PID control method, and finally making use of MATLAB/Simulink to complete the simulation. Simulation results show that compared with traditional aerodynamic control system, this method can reduce the response time of aerodynamic missile and enhance the stability of the control system obviously.

scholarly journals GPC-Based Stable Reconfigurable Control

2003 ◽  
Author(s):  
Jianjun Shi ◽  
Atul G. Kelkar ◽  
Donald Soloway
Keyword(s):  
State Space ◽  
Predictive Control ◽  
Flight Control ◽  
Actuator Saturation ◽  
Control Design ◽  
Generalized Predictive Control ◽  
Control Law ◽  
Reconfigurable Control ◽  
Space Formulation ◽  
The Stability

This paper presents development of multi-input multi-output (MIMO) Generalized Predictive Control (GPC) law and its application to reconfigurable control design in the event of actuator saturation. The stability of the GPC control law without reconfiguration is first established using Riccati-based approach and state-space formulation. A novel reconfiguration strategy is developed for the systems which have actuator redundancy and are faced with actuator saturation type failure. An elegant reconfigurable control design is presented with stability proof. A numerical example with application to reconfigurable flight control is presented to demonstrate the results presented in the paper.

scholarly journals Application of Derivative Transform Spectroscopy in Gas Detection

2021 ◽  
Vol 299 ◽  
pp. 02005
Author(s):  
Tingting Chen ◽  
Chun Wang ◽  
Jingqiu Liang ◽  
Jingsong Li
Keyword(s):  
Signal Processing ◽  
Noise Suppression ◽  
Time Signal ◽  
Spectroscopy Analysis ◽  
Signal Processing Algorithm ◽  
Methane Absorption ◽  
Laser Absorption ◽  
Derivative Spectroscopy ◽  
Filtering Technique ◽  
The Stability

Digital filtering technique is of great significance in real-time signal processing and analysis, but the stability, efficiency and flexibility of filter algorithm are important indicators to reflect its application value. In this paper, an adaptive derivative transformation based on Savitzky-Golay filter algorithm was proposed for laser absorption spectroscopy analysis. To demonstrate this analysis algorithm, first-order and second-order derivative spectroscopy are evaluated for the analysis of infrared methane absorption spectra, and compared with the original direct absorption spectral signals. The results indicated that the proposed signal processing algorithm has good performance on noise suppression and spectral resolution improvement, and the 2nd derivative spectroscopy shows better de-noising efficiency.

scholarly journals Umbrella Labyrinth Sedimentation Device Study

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Shuisheng Wang
Keyword(s):  
Water Quality ◽  
Vertical Direction ◽  
Mutual Interference ◽  
Water Diversion ◽  
Swash Plate ◽  
Parallel Axis ◽  
The Stability ◽  
Combination Mode ◽  
Vertical Height ◽  
Pond Design

Umbrella-type mud-water diversion labyrinth sedimentation device, which is characterized by the combination of two swash plate and wing plate into an umbrella type with a set angle, the angle range of the two swash plate is 15º--100º, the vertical height of the swash plate is 60-70 mm, the parallel axis of the wing plate is the vertical direction, the height is 10-20 mm. the whole adopts the modular combination mode, and can be freely combined and disassembled according to different pond design, swash plate The interval (sedimentation distance) can be freely adjusted, mud take the mud road and water take the water road, to avoid the mutual interference of the water and mud road, to achieve the stability of the water quality. The turbidity of the sedimentation pond is low, stable in 0.3-2.0 NTU.

scholarly journals Robust dynamic inversion control of flight control system based on L1 adaptive structure

2021 ◽  
Vol 39 (5) ◽  
pp. 995-1004
Author(s):  
Yu LI ◽  
Xiaoxiong LIU ◽  
Ruichen MING ◽  
Shaoshan SUN ◽  
Weiguo ZHANG
Keyword(s):  
Control System ◽  
Flight Control ◽  
Dynamic Performance ◽  
Dynamic Inversion ◽  
Control Law ◽  
Flight Control System ◽  
Parameter Uncertainties ◽  
Strong Robustness ◽  
Adaptive Structure ◽  
The Stability

Nonlinear Dynamic Inversion(NDI) control has excellent rapidity and decoupling ability, unfortunately it lacks the essential robustness to disturbance. From the perspective of enhancing the robustness, an adaptive NDI method based on L1 adaptive structure is proposed. The L1 adaptive structure is introduced into the NDI control to enhance its robustness, which also guarantees the stability and expected dynamic performance of the system suffering from the disturbance influence. Secondly, the flight control law of the advanced aircraft is designed based on the present method to improve the robustness and fault tolerance of the flight control system. Finally, the effectiveness of the flight control law based on the present approach is verified under the fault disturbance. The results showed that the flight control law based on L1 adaptive NDI has excellent dynamic performance and strong robustness to parameter uncertainties and disturbances.

LQG-Based Robustifying Flight Control System

2003 ◽  
Author(s):  
D. Griffin ◽  
A. G. Kelkar
Keyword(s):  
Control System ◽  
Flight Control ◽  
Controller Design ◽  
Second Step ◽  
Flight Control System ◽  
Robust Controller ◽  
Fighter Aircraft ◽  
Stability Robustness ◽  
Uncertainty Model ◽  
The Stability

This paper presents a robust controller design for an automatic flight control system (AFCS) for a fighter aircraft model with eight inputs and seven outputs. The controller is designed based on McFarlane-Glover robustifying technique using a simple baseline LQG design. Controllers designed purely based on traditional LQG techniques are known to have no guaranteed robustness margins. The McFarlane-Glover technique can be used to enhance the stability robustness of the baseline LQG design using a two-step design process. In the first step, an LQG controller is designed which is optimized only for performance without any consideration to robustness. In the second step, the performance optimized LQG design is rendered robust using McFarlane-Glover procedure. The robustifying procedure uses a coprime factor uncertainty model and H∞ optimization. An important advantage of this procedure is that no problem dependent uncertainty modelling or weight selection is required in the second step of the process. The robustifying procedure also yields the quantitative estimate of the robustness.

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