This article proposes a novel adaptive super-twisting sliding mode control scheme with a time-delay estimation technique (ASTSMC-TDE) to control the yaw angle of a single ducted-fan unmanned aerial vehicle system. Such systems are highly nonlinear; hence, the proposed control scheme is a combination of several control schemes; super-twisting sliding mode, TDE technique to estimate the nonlinear factors of the system, and an adaptive sliding mode. The tracking error of the ASTSMC-TDE is guaranteed to be uniformly ultimately bounded using Lyapunov stability theory. Moreover, to enhance the versatility and the practical feasibility of the proposed control scheme, a comparison study between the proposed controller and a proportional-integral-derivative controller (PID) is conducted. The comparison is achieved through two different scenarios: a normal mode and an abnormal mode. Simulation and experimental tests are carried out to provide an in-depth investigation of the performance of the proposed ASTSMC-TDE control system.

This paper proposes a new method to control the pose of a camera mounted on a two-axis gimbal system for visual servoing applications. In these applications, the camera should be stable while its line-of-sight points at a target located within the camera’s field of view. One of the most challenging aspects of these systems is the coupling in the gimbal kinematics as well as the imaging geometry. Such factors must be considered in the control system design process to achieve better control performances. The novelty of this study is that the couplings in both mechanism’s kinematics and imaging geometry are decoupled simultaneously by a new technique, so popular control methods can be easily implemented, and good tracking performances are obtained. The proposed control configuration includes a calculation of the gimbal’s desired motion taking into account the coupling influence, and a control law derived by the backstepping procedure. Simulation and experimental studies were conducted, and their results validate the efficiency of the proposed control system. Moreover, comparison studies are conducted between the proposed control scheme, the image-based pointing control, and the decoupled control. This proves the superiority of the proposed approach that requires fewer measurements and results in smoother transient responses.

This study proposes a novel autonomous system that is able to retrieve an underwater glider safely and quickly. After a long-period mission, the glider is out of its energy, floats up in the middle of the sea, and needs retrieval. However, most of the recovery processes are conducted manually, which is not effective and even damages the glider or injures the worker. In this study, we propose the use of a remotely operated vehicle (ROV) in a recovery process that consists of three stages: (i) driving the ROV into the near area of the glider, (ii) automatically catching the glider using the ROV’s onboard sensors and capturing mechanisms, and (iii) retrieving the glider to the mother ship or station. Mathematical models were formulated to realize the feasibility of the system. A cascade adaptive sliding mode control-proportional integral controller is designed to cope with the thruster’s characteristics, the dynamics of the ROV and the glider, and oceanic disturbances. Finally, simulation studies were conducted in the system operation scenarios and their results validate the efficiency of the proposed process.

In this article, the adaptive super-twisting sliding mode control is designed and applied for three degrees of freedom robot with unknown perturbation model of the system. This method combines an advanced property of adaptive law and the high order super-twisting sliding mode control to enhance the sliding manifold surface which can reach the equilibrium point in the shorter time. Likewise, the stability and estimation of the unknown perturbations of the controlled system are satisfied by Lyapunov stability theory and Moreno"s theorem. The effectiveness of adaptive super-twisting sliding mode control in unknown perturbation of the system is verified by comparing with the general super-twisting sliding mode control method. Therefore, a comparison results of both controllers via simulation are implemented. Also, the root mean square error is calculated for evaluation of the both controller"s tracking performances.

This paper reveals the proposed method to operate landing angular motion of ducted-fan unmanned aerial vehicle (DUAV). The angular motion frequently varies during the landing stage. Additionally, the DUAV system is a complex system with uncertain parameters or incorrectly identified parameters, and the yaw angle has to be controlled in the proper position before grounding. Because of issues with structure of the system and identification in the real model of DUAV, a model-free control technique is approached by combining time-delay estimation (TDE) and integral sliding mode law (ISMC). Thanks to the TDE technique provides a model-free method for the complex system as DUAV. Hence, a novel control method is designed to achieve the desired angular motion. Besides, the ISMC method is a good solution for tracking performance. The stability of the whole system is guaranteed by the Lyapunov theory. The comparison between the TDE-ISMC and sliding mode control (SMC) is conducted in several cases to verify the effectiveness of the proposed TDE-ISMC control.

Parkinson’s patients experience severe pathological tremors because of abnormality of central oscillator that entrains the corticothalamic system and the basal ganglia. Normally, medications are used to decrease involuntary antagonistic muscle contraction can affect life, therefore, safe treatment methods have attention. The mechanical vibration absorber is an outstanding method, and can be used as an alternative treatment. Based on the biodynamics of the human arm, the objective of this study is to provide the performance of Parkinson’s patients and to design a model-free control to suppress their pathological tremor, called an active dynamic vibration absorber system (DVAs). An active DVA with model-free control inside can handle the complex system, disturbances, complicated working behavior, and so forth. Frequency of resting tremor as resonance frequencies of shoulder and elbow muscle is activation operating. The response of the active DVAs is studied in the case that it is attached to the arm and compared to the passive DVA with excitation frequencies in the previous study. The results verify the effectiveness of active DVA with controller inside, which can reduce the pathological tremor in amplitude feature in Parkinson's patient’s arm.