The present paper proposes a Fast Terminal Sliding Mode Controller (FTSMC) for tracking uncooperative ground targets with a quadrotor UAV (QUAV). The method combines visual feedback information with onboard measurements to ensure accurate and reliable tracking. Simulation results reveal significant improvements in response time and minimal steady-state errors compared to the conventional first-order Sliding Mode Controller (SMC). These findings confirm the effectiveness of the FTSMC for dynamic and real-world applications, offering high precision, robustness, and fast convergence in finite time.

This work explores target interception with quadrotors, adapting missile guidance laws to aerial platform dynamics. A Line-of-Sight (LOS) guidance model, combined with an Active Disturbance Rejection Control (ADRC) system, addresses target maneuverability. The ADRC compensates for disturbances and motion variations, ensuring stable and precise interception. Simulations show the approach’s robustness and superior performance, highlighting its potential for autonomous aerial defense and interception in uncertain environments.

This study introduces SENSE, an innovative sensorless external force estimation framework for humanoid robots, built on a model-driven approach. Unlike conventional methods that depend on the simplified Linear Inverted Pendulum (LIP) model and offline data processing, SENSE enables real-time and online estimation. By leveraging centroidal dynamics and integrating angular momentum, our approach accurately infers external forces without the need for Force/Torque (F/T) sensors. The proposed method is validated in simulation using the NAO humanoid robot model within the qiBullet physics engine, under both static standing and realistic dynamic walking conditions. Robustness is evaluated using two external force profiles: constant and time-varying (e.g., sinusoidal). Results show that SENSE provides accurate and stable force estimation, even in challenging scenarios such as foot contact transitions where low-cost sensors like Force-Sensing Resistors (FSRs) typically become unreliable. With its low computational cost and reliance only on onboard sensors, SENSE offers a practical alternative to expensive F/T sensors for medium-sized humanoid platforms. To promote reproducibility and further research, the full implementation is publicly available.

The study of control techniques for exoskeleton robots used in upper-extremity rehabilitation is gaining popularity. These robots are connected to the human upper limb at multiple points, allowing for smooth and independent joint movements. Therefore, providing a robust, precise, and safe control system is necessary. Sliding control-based approaches are well reputed for their robustness to parameter uncertainties, modeling errors, and external disturbances. Nevertheless, their major disadvantage is chattering. This paper describes two controllers based on sliding mode theory to reduce this undesirable effect: the generalized variable structure control and the higher-order finite-time sliding mode control. The former incorporates the derivative of the torque input in the model, while the latter is based on homogeneity and higher-order sliding modes to diminish chattering. A comparison between the two controllers is achieved by simulating passive rehabilitation mode.

Search and tracking of non-cooperative mobile targets, maneuvering in an area monitored by a quadrotor UAV is investigated. In order to reach this aim, We propose a robust approach based on vision and sliding mode controller. The proposed strategy is an Image-Based Visual Servoing (IBVS) approach using targets visual data projected in a virtual camera. For an effective visual target searching, a circular search trajectory is followed, with a high altitude using the Camera Coverage Area (CCA). A Sliding Mode Controller (SMC) based on Reaching Law with a Power Rate (RLPR) is applied to ensure the QUAV control in the presence of external disturbances and measurement uncertainties. Simulation results are presented to assess the proposed strategy considering different scenarios.

A homogeneous continuous sliding mode control scheme based on finite time stability is developed in this paper for an upper limb exoskeleton robot dedicated for rehabilitation. Indeed this type of robot interacts directly with human limbs whose dynamics are unknown and different for users. Therefore, the main idea is to provide a robust motion control of the exoskeleton robot using a continuous higher order sliding mode controller despite parameters variations, uncertainties and external disturbances. The proposed controller combines the homogeneity concept and the super-twisting algorithm. Finite time stabilization is achieved using the first part of the controller while disturbance rejection is granted by the second part of the controller. Performance of the controller and its robustness are illustrated through simulations of trajectory tracking tests corresponding to passive rehabilitation exercises.

In this paper, we present the mechatronics design, modeling and preliminary control of a new 5 degrees of freedom (DoF) exoskeleton, dedicated for the upper limb rehabilitation. The designed exoskeleton allows the shoulder rotations as well as the elbow movements. It combines the advantages of both parallel and serial mechanisms. It has been designed by considering the main factors in designing a general use robotic force-feedback device and the human upper limb specications. This active device, as a kind of haptic device, provides two ways communication in both position and force, and allows patients to interact with the virtual reality system and practice activities of daily living (ADL) assistance. The kinematic model of the exoskeleton is presented. In order to evaluate the performance of the exoskeleton, a preliminary position and torque controllers have been implemented.

Visual channel dominates the design of the cockpit, and auditory channel is progressively being used as well. However, tactile displays are almost abstract in the cockpit designs. Whereas, many research proved that several applications exist where the tactile displays may become an important or even essential choice. This is due to the fact that the visual feedback is not suitable, not adequate, or surcharged and that the visual attention is usually limited to a simple entity. In this paper, we propose a design of a low-cost tactile feedback system to provide the pilot with better insight in the flight path and prevent limitations during flight. In the first part of the paper, we develop an effective control strategy based on inverse dynamic to solve the problems of use of the low-cost tactors. The obtained results showed reduction of 48 % in settling time. The second part describes the use of Fuzzy Logic Controllers (FLC) to compute a new form of tactile output of the translation of a pertinent flight data information and flight envelope to vibrotactile feedback signals. And in the last part, we develop a wireless (and USB) vibrotactile feedback device consisting of 16 embedded tactors controlled with an inverse dynamic strategy via an arm Cortex M3 architecture. Pilots equipped with the developed tactile display were capable of successfully flying in a simulator. They confirm that tactile feedback is an interesting way of feeding back information about the airplane’s state, in order to give a better understanding of what the airplane is doing during controlled flight.

This paper deals with the modeling and instrumentation design for position and torque control of a new designed 4 degrees of freedom (DOF) haptic device to be used in a virtual reality laparoscopic simulator or as an input device for telepresence applications. Low-cost instrumentation is designed for torque/force control using no-contact current sensors and a force sensor. The relations between the applied force/torques and the output voltages are determined by calibration that shows that such low-cost sensors perform just as well as highly accurate sensors. The forward and inverse kinematics models of the 4-DOF are also formulated explicitly by using analytical methods. Based on this models and by introducing the kinematics constraints defined for the parallel part of the device, position control is performed successfully using PD controller. We carried out a PID controller for efficient torque control thanks to the introduced torque sensors. Experimental results that validate and encourage the proposed design are presented.

This paper presents a theoretical and experimental study of a model describing the heat exchange between a fingertip and any given touched object. This model is solved and implemented on a thermal display incorporated into a haptic device. Thermal feedback can assist in object identification, representation or in the creation of a complete haptic signature of a given object. Alternatively, thermal feedback could be used as a sensory substitute or adjunct for visual or tactile feedback. Experimental results validating the proposed thermal model are evaluated when touching virtual objects in virtual environments.