Position Commands Research Articles

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.

The main features of military law in Ukrainian lands during the XVIII century

The study of Ukrainian military history in general and military law in particular is of paramount importance in the context of Russian aggression against Ukraine. The period of the 18th century occupies a prominent place in Ukrainian history due to the incorporation of Ukrainian lands into other states, primarily the Russian Empire. Codification by the Russian administration was understood as the absorption of Ukrainian law into Russian law and the complete obliteration of the Ukrainian legal tradition. However, Ukrainian codifiers, using the principle of legal continuity, were able to create original legal collections which had an obvious connection with previous achievements in the field of law. It has been established that the focus of regulation of military-legal relations was on the problems of mobilisation, which was applicable to all segments of Ukrainian society. It has been determined that military service has become the main condition for acquiring land ownership. The article enshrines in law the need to abolish the possibility of evading mobilisation by transferring land as a loan, pledge, inheritance, etc. The law required military service by the legal owner of the land. It has been found that the law provided for the possibility of refusing conscription in case of emergency, but even in such circumstances, the landowner had to take care and appoint another serviceman from among his relatives. Moreover, it has been proved that legal norms also regulated the prosecution of military personnel who violated law and order during redeployment, cantonment, and communication with each other and the local population. In addition, it has been shown that the most common universal type of punishment for violation of military laws was a fine, but certain features of the punishment were determined by the social status of the offender – the nobility was deprived of their social privileges as an additional punishment, and lower-ranking soldiers were subject to corporal punishment. Thus, it has been determined that military legal norms paid special attention to the regulation of personnel policy: people who were unconditionally brave, experts in military affairs, and those who enjoyed universal respect were recommended for command positions. Considering all the above circumstances can be useful in developing a new military doctrine of Ukraine and enrich it with invaluable historical experience.

Attitude tracking of rigid-liquid-flexible coupling spacecraft by active disturbance rejection control

Considering the complex attitude dynamics of Rigid-Liquid-Flexible Coupling Spacecraft, especially when the large amplitude sloshing of liquid exists in rapid attitude maneuver, the conventional control design method based on the linearized model is not suitable for the significant coupling and strong nonlinearity. By contrast, Active Disturbance Rejection Control is model-independent and easy to design and implement. In this paper, the three main components of Active Disturbance Rejection Control, Tracking Differentiator, Extended State Observer and Nonlinear State Error Feedback are comprehensively applied to the attitude tracking control of Rigid-Liquid-Flexible Coupling Spacecraft. Firstly, two cascaded Tracking Differentiators are used to arrange the transition process of the attitude command, which not only reduces overshoot and oscillation of the tracking process, but also obtains the angular acceleration information of attitude trajectory for feed-forward compensation. Secondly, the total disturbance caused by liquid sloshing and flexible vibration is observed by Extended State Observer and compensated synchronously. Finally, the Nonlinear State Error Feedback is used to further improve the transient behavior and steady-state quality of the control system. The simulation results show that the tracking accuracy of the attitude and angular velocity using the Active Disturbance Rejection Control are about 3–27 times and 6 to 115 times that of the PID control, respectively. The convergence time, overshooting are also significantly less than the PID control.

The Social, Educational, and Early Military Backgrounds of Senior Officers of the British Army of the Second World War, 1944–1945

Abstract Seventy-eight officers held senior command positions at army, corps, and divisional level in Britain’s three main field armies – the Second (North-West Europe), Eighth (Italy), and Fourteenth (Burma) – at the end of the Second World War. Using a range of source material, including their private papers, this article examines their socio-economic and family background, education, and early career development and finds that as a group, they were more representative of the middling classes than heretofore depicted. They were also far more diverse in education and place of birth: twenty-one were born outside Britain. As this article argues, the make-up of the three armies also differed, suggesting the formation of a more elite, home-grown, ‘first team’ for service with the Second Army in North-West Europe.

Основные направления оптимизации конфликтности управленческой среды в воинских коллективах технологиями социального регулирования

The article investigates methods for optimizing conflict management within the administrative environment of military units through social regulation technologies. It analyzes the specific features of such units, including their hierarchical structure, discipline, and the diversity of social, cultural, and educational groups. Various types of social regulation technologies are examined, including normative, realistic, and idealistic approaches, their roles in conflict resolution, and their impact on the manageability and cohesion of military units. The theoretical part examines the causes of conflicts, such as unreasonable managerial decisions, violation of social justice, excessive guardianship of superiors and insufficient prestige of command positions. The article emphasizes the importance of integrating theoretical knowledge and practical skills in conflict management to enhance the combat readiness and effectiveness of units. It also highlights the need for the systematization and dissemination of best practices in conflict resolution within military units.

Medics as influencers: a historical analysis of British Army military medical exercises in Kenya over two decades

IntroductionAnnual British Army medical training exercises have run in Kenya since the early 1990s, initially with a dual purpose—to deliver the Kenyan Extended Programme of Immunisation (in remote locations) and...

Adaptive Formation Tracking Control of Multiple Vertical Takeoff and Landing UAVs With Bearing-Only Measurements.

This article studies the leader-following formation tracking control problem of multiple vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs) subject to uncertain parameters, in which the target formation configuration is defined by using the interneighbors' bearing vectors. An adaptive formation control algorithm with bearing-only measurements is proposed under a hierarchical control framework. More specifically, a saturated adaptive distributed control force is developed in the position loop with bearing-only measurements. Since the bearing vectors with respect to the neighbors can be directly measured by low-cost onboard cameras, the proposed formation algorithm can be implemented without interagent communication. Subsequently, in the attitude loop, an adaptive hybrid control scheme via two modified Rodrigues parameters (MRPs) sets is proposed, which achieves the command attitude tracking globally and also avoids the unwinding problem of MRPs. Based on the Lyapunov stability analysis and hybrid theory, we prove that the overall closed-loop error system is globally asymptotically stable. Finally, we provide a numerical example to demonstrate the effectiveness of the proposed control algorithm.

Studying Motor Praxis in Children With Varying Levels of Developmental Coordination Disorder

Background and Aims This research aimed to examine the gesture production ability of motor praxis among children with developmental coordination disorder (DCD) and children on the verge of developing DCD and compare it to typical children of the same age and younger. Methods For this reason, 91 boys (6-12 years old) were selected as sample size and divided into five groups (20 children with typical development, 14 children with DCD, 17 children on the verge of developing DCD, 20 typically-developed children aged 8-9 years, and 20 typically-developed children aged 6-7 years). To find the children with DCD, we employed the developmental coordination disorder questionnaire 7th edition (DCDQ-7) and the Bruininks–Oseretsky test of motor Proficiency. The Dewey gesture production test was performed to investigate motor praxis. Data analysis was performed using variance analysis and an independent t test. Results Comparing the subjects’ performance in different conditions showed that their performance in transitive motor praxis was better than intransitive one (P<0.05). Also, the comparison of verbal command and imitation position showed that between the two DCD groups, the performance in the imitation movements was significantly better (P<0.05). While in the same age control group, no significant difference was seen between motor praxis in two conditions (P>0.05). The between-group comparisons showed that the performance of two DCD groups was disrupted compared to that of the control group at the same age. The performance of the DCD group compared to lower-age children with typical development (8-9 years old) was not different at the verbal command condition. In the imitation position condition, the DCD group performed significantly better than the lower-age children groups (P<0.05). Conclusion These results show that DCD subjects have developmental delays in performing motor praxis under verbal command.

Kipchak Networks of Power in Mongol China

Kipchak tribes have always had an important military role in the Mongol Empire. In this article, a Kipchak tribe that was at the center of this military role and formed a strong social and political network in Mongolian China is discussed. In addition to their military roles and the social capital they use to strengthen their influence in the Mongolian civil bureaucracy in China, the functioning of their family structure and its benefits are shown. Accordingly, even the marriages of the members of the Kipchak tribe in question served to establish or expand their power networks. Local records of the Jiking Region in China, which hosted many prominent immigrants during the Yuan period, provide important evidence for this investigation. Tuq Tuq’a’s relatives and descendants, who took care to preserve their identity as an elite military unit until the end of the dynasty, both in the civil bureaucracy and in the military field, successfully maintained the position of Commander of the Imperial Guard; In addition, this important and powerful military clan gained significant property and financial advantages in the Jiking Region. This nomadic group that settled in China became an important part of the Yuan Dynasty.

Forced Straightening of the Back Does Not Improve Body Shape

Background: Sitting for a long time causes various postural problems, such as slump sitting. It has been reported that employing a corrected sitting position while lifting the sternum is effective in improving this form of posture. We investigated how a corrected sitting posture with the lifting of the sternum is different from a forced position that is applied through the command and passive positions. Materials and methods: The postural angle of 270 subjects aged 19–23 years was measured in the passive, forced, and corrected positions using a Saunders inclinometer and a Formetric 4D system. Results: As a result, the corrected position had a small range (min–max) at all angles, but the forced position and passive position had a large range (min–max). The lumbar lordosis angle in the corrected position showed positive values throughout its range (min–max), while the other groups showed negative values, which indicates the kyphotic position of the lumbar section. In addition, the percentage error in the corrected position was small, but it presented high values in the other groups. When comparing the average angles between the groups, there were substantial changes observed between the corrected position and the other groups. It was found that the corrected position with the sternum lifted, which is applied to improve slump sitting in the clinical environment, exhibited an angle that differed from that of the forced position and the passive position. Conclusions: Our results suggest that a forced position on the command “scapular retraction” does not meet the clinical assumptions of posture correction, in contrast to the corrected position with the lifting of the sternum for the improvement of slump sitting. The accurate correction of the position of the sternum and sacrum improves the position of the spine in the sagittal plane, enabling physiological values for the kyphosis and lordosis angle parameters to be obtained. This approach combines the ease of execution and precision of the effect. The fact that this method does not require complex tools to accurately correct the body encourages the implementation of this solution in clinical practice.

The motivational and volitional sphere of transport police officers

The hypothesis of study: there are statistically significant differences in the motivational and volitional sphere of transport police officers in command and civilian positions. This is due to the specifics of the professional activities of employees of command positions: the importance of goals, high requirements for stress resistance, personal reliability, discipline, endurance. This requires high motivation and strongwilled endurance. The study involved 44 employees of the East-Siberian Linear department of the Ministry of Internal Affairs of the Russian Federation on transport aged 26 to 42 years, all men. Of these, 22 are employees who hold command positions, 22 are employees who hold civilian positions. The results of the study confirm the hypothesis. The motivational and volitional sphere of employees of command and civilian positions of the transport police has statistically significant differences: for citizens, comfort and good conditions are important for a sense of well-being at work. Whereas employees of command positions prefer to realize in the profession through the opportunity to be useful to people and help them.

Smoothing interpolation of five-axis tool path with less feedrate fluctuation and higher computation efficiency

Five-axis machine tools are widely used in aerospace, die and mold industries. Most of the time, the tool path is described by connecting a series of short linear segments. The tangency discontinuity of the linear segments leads to the discontinuity of the kinematic profiles, hence generating discontinuous interpolation points, and resulting in fluctuation of machine motion, which reduces the machining efficiency and causes excessive tracking and contouring errors. This paper aims to generate smooth interpolation points at servo sample intervals with the proposed G2 continuous five-axis corner rounding algorithm suitable for reducing feedrate fluctuation along the smoothed toolpath and improving machining efficiency, and the modified jerk-limited feedrate planning algorithm suitable for eliminating feedrate fluctuation within the feedrate planning units and improving interpolation computation efficiency. In this paper, the five-axis linear segments are first smoothed by curvature-optimized cubic Bezier splines, which reduces the number of the feedrate planning units along the smoothed toolpath and improves machining efficiency. Then, the jerk-limited feedrate planning algorithm is modified to ensure that the time interval of each different scheduled feedrate phase is an integer multiple of the axis position control loop closure time (i.e. servo sample interval), which eliminates the feedrate fluctuation within each feedrate planning unit and reduces the interpolation computation load of position command in each interpolation period (i.e. servo sample interval). At last, the effectiveness of the proposed algorithm is demonstrated with simulations and experiments following a five-axis, curved tool path on a CNC (Computer Numerical Control) machine tool.

Wyzwania Sił Zbrojnych Rzeczypospolitej Polskiej w oparciu o ustawę o obronie ojczyzny i członkostwo w Sojuszu Północnoatlantyckim

The article, presents the role and tasks of the Polish Armed Forces in ensuring the security of the State, stressing that the formation of the security environment, in the state should be an overriding value, especially with regard to current threats. The paper presents information on the obligations and benefits of Poland’s membership in the North Atlantic Treaty (NATO), and also addresses, the current structure of the Polish Armed Forces, describing the most important command positions in the Polish Armed Forces and their main tasks.

Labour Under New Management

ABSTRACT: In the next British general election, due to happen within the year, the Labour Party is set to sweep into power after fourteen years in opposition. Its two major rivals, the Conservative Party and the Scottish National Party (SNP), have imploded in scandal and division. The financial meltdown unleashed by the forty-nine-day tenure of former Prime Minister Liz Truss propelled Labour to a commanding position in national opinion polls, one that her successor, Rishi Sunak, has been unable to dent at the time of writing. A police investigation into misappropriation of donations and the resignation of First Minister of Scotland Nicola Sturgeon have undermined the SNP at a moment when the pandemic, war, and Conservative vulnerability have made the case for independence seem far less pressing than it did a decade ago. Local council and by-election results from the rural shires of Yorkshire to the satellite towns of Glasgow suggest that Labour is advancing on all fronts.

Labour Under New Management

ABSTRACT: In the next British general election, due to happen within the year, the Labour Party is set to sweep into power after fourteen years in opposition. Its two major rivals, the Conservative Party and the Scottish National Party (SNP), have imploded in scandal and division. The financial meltdown unleashed by the forty-nine-day tenure of former Prime Minister Liz Truss propelled Labour to a commanding position in national opinion polls, one that her successor, Rishi Sunak, has been unable to dent at the time of writing. A police investigation into misappropriation of donations and the resignation of First Minister of Scotland Nicola Sturgeon have undermined the SNP at a moment when the pandemic, war, and Conservative vulnerability have made the case for independence seem far less pressing than it did a decade ago. Local council and by-election results from the rural shires of Yorkshire to the satellite towns of Glasgow suggest that Labour is advancing on all fronts.

Generał brygady Leon Pachucki (1872–1932) – żołnierz Armii Polskiej we Francji i bohater wojny polsko-rosyjskiej 1920 r. Zarys biografii

The subject of the research is the figure of Leon Pachucki, a brigadier general of the Polish Army, who took part in World War I and the Polish-Russian War. The aim of the article is to present his military career, both in the Russian Army and later in the Polish Army. The text is based mainly on documents collected in the Central Military Archives, and on available literature supplementing the archival materials. On their basis, it was possible to analyze the stages of his military career, his achievements on the battlefields, his service in higher command positions in the interwar period and his social activities after retirement. He was a hero of the Polish-Russian War in 1920 – for his courage on the battlefield, he was awarded the Order of Virtuti Militari 5th class and the Cross of Valor. The future general was born in 1872 in Suwałki and as a youth he joined the Russian army. He served in this army until 1918, recently in the Russian corps in the Balkans. In spring that year he came to France, where he commanded the 3rd Rifle Regiment (Polish Army in France). Together with him, he came to Poland in April 1919 and took part in the Polish offensive in Volyn. At the end of June this year, he took the position of the commander of the infantry in the 1st Rifle Division of the General Haller's Army. Three months later, he became the commander of the XXV Infantry Brigade. As its commander, he showed courage on leading the defense of the locality of Pohrebyszcze at the turn of May and June 1920. In September 1921, he became the deputy commander of the Corps District No. IV Lodz, and in 1925 he took up a similar position in the Command of the Corps District No. IX Brest. After retiring in 1927, he moved to Lodz, where he died in 1932. It is worth adding, that he was the only one general of the army of the Second Polish Republic buried in this city before World War II.

Finite-time high-order sliding mode control of supercavitating vehicle based on perturbation observer

High precision control is one of the most important problems in the research of supercavitating vehicle. Specific motion mode and complicated environmental factors lead to some great challenges in control, such as model uncertainties, strong coupling and nonlinearity, and unknown external disturbances. Under the influence of these factors, effectively ensuring the integrated control of the depth and attitude of the supercavitating vehicle has become a research hotspot. In this paper, a high-order sliding mode control method based on a finite-time convergence perturbation observer is proposed for depth and attitude coordinated control of the longitudinal dynamics model of the supercavitating vehicle. A special sliding mode surface and a novel high-order sliding mode reaching law solve the problem of depth and attitude integrated modeling and control model coupling respectively. For the total perturbation of the system generated by the cavitation shape, the planing force and the wetted rate of the tail fins and unknown external disturbances, a finite-time convergence perturbation observer is designed to observe and compensate it in the control law. The system can be converged in a finite time by the Lyapunov stability method. The simulation results indicate that the supercavitating vehicle can accurately track the depth and attitude command using the proposed control law under the uncertainty, which verifies the robustness of the control system.

Visual Servo Kinematic Control of Delta Robot using YOLOv5 Algorithm

Industrial delta robots with motion-and vision-base controllers, providing high-precision and fast/flexible motion, normally come with high cost and complex software. Low-cost delta robots with vision solution could be beneficial to vast industries to increase productivity and to reduce labor cost. A delta robot using a low-cost motion controller and an open-source vision system is developed to accomplish real-time visual servoing with high motion accuracy. In the low-cost motion controller, three parallel links’ upper-arm angles, computed from inverse kinematics for a given desired target position by a high-level computer, are used as reference position commands for three AC-motor drives. A low-level Arduino microcontroller is employed to convert these links’ angles to high-frequency pulses and on-off signals for synchronously controlling three motor angles and direction. Experimental results of a point-to-point motion tracking exhibit high-precision repeatability. Synchronous pulse generation from Arduino microcontroller and structural misalignments of parallel links are major challenges for achieving high motion accuracy. For the vision-based system, the YOLOv5 algorithm is implemented along with a Python GUI Application. Then, the visual-servo performance is evaluated on localization accuracy and recognition rate of 3-color objects. However, a partial object occlusion can reduce the visual classification rate. A sorting task of 4-category medicine boxes demonstrate a high-speed pick-and-place operation using the low-cost visual-servo system of this delta robot. Therefore, integration of low-cost visual servoing with this delta robot can revolutionize various industries, like automobile, pharmaceutical, and food sectors, in separating, sorting and packing applications.

Finite-Time Anti-Saturated Formation Tracking Control of Multiple Unmanned Aerial Vehicles: A Performance Tuning Way

A highly effective control method is very important to guarantee the safety of the formation of flying missions for multiple unmanned aerial vehicles (UAVs), especially in the presence of complex flying environments and actuator constraints. In this regard, this paper investigates the formation tracking control problem of multiple UAVs in the presence of actuator saturation. Firstly, a brand-novel finite-time anti-saturated control scheme is proposed for multiple UAVs to track the desired position commands, wherein the tracking performance is tuned by introducing a logarithmic function-based state-mapping policy. Then, an adaptive scheme based on projection rules is devised to compensate for the negative effects brought by the actuator saturation. Based on the proposed formation tracking controller, the finite-time formation tracking performance tuning and control saturation problems can be addressed simultaneously with a comparatively allowable system robustness. Finally, three groups of illustrative examples are organized to verify the effectiveness of the proposed formation tracking control scheme.

Robust Collision-Free Guidance and Control for Underactuated Multirotor Aerial Vehicles

This paper is concerned with the robust collision-free guidance and control of underactuated multirotor aerial vehicles in the presence of moving obstacles capable of accelerating, linear velocity and rotor thrust constraints, and matched model uncertainties and disturbances. We address this problem by using a hierarchical flight control architecture composed of a supervisory outer-loop guidance module and an inner-loop stabilizing control one. The inner loop is designed using a typical hierarchical control scheme that nests the attitude control loop inside the position one. The effectiveness of this scheme relies on proper time-scale separation (TSS) between the closed-loop (faster) rotational and (slower) translational dynamics, which is not straightforward to enforce in practice. However, by combining an integral sliding mode attitude control law, which guarantees instantaneous tracking of the attitude commands, with a smooth and robust position control one, we enforce, by construction, the satisfaction of the TSS, thus avoiding the loss of robustness and use of a dull trial-and-error tweak of gains. On the other hand, the outer-loop guidance is built upon the continuous-control-obstacles method, which is incremented to respect the velocity and actuator constraints and avoid multiple moving obstacles that can accelerate. The overall method is evaluated using a numerical Monte Carlo simulation and is shown to be effective in providing satisfactory tracking performance, collision-free guidance, and the satisfaction of linear velocity and actuator constraints.