This paper presents the design and modeling of a flying-type fire extinguishing system. Fire accidents present very hazardous environments, and firefighters are in danger of losing their lives while putting out the fire. Strict safety measures should be considered to guarantee safe working conditions for firefighters, which is not the case every time, as fatalities and casualties are still being recorded. For this reason, a novel fire extinguishing system is proposed to provide more safe firefighting and survivor searches. The system studied in this paper is a pilot model that consists of a water jet-based actuation system to control the flying motion of the robot. The dynamic model of this flying robot is derived using the actuation forces, water jet system characteristics, and related information. The mathematical system model is detailed, a sliding-mode control system and a proportional-integral-derivative controller are designed, and comparative simulation tests are carried out.

Barge ships are designed to transport and assemble heavy and massive pieces of equipment at sea. Active propulsion systems are not installed in this type of ship, so the desirable motion and positioning of these ships can only be achieved with the assistance of several tugboats. In this study, the dynamical characteristics of barge conveying systems were formulated and robust control systems were designed to ensure efficient barge operation. To achieve these objectives, we first developed a mathematical model of a barge ship, which incorporated a novel conveying system configuration using tugboats. We then designed a robust controller for the tugboats that used the sliding mode law to deliver the desired barge motion performance. Finally, the usefulness of the proposed configuration and controller was verified via simulation studies using another system with an $H_{\infty }$ controller. The proposed sliding mode controller showed superiority, especially in terms of robustness against disturbances.

In this study, we propose and analyze three designs of a novel aerial system that aims for autonomous firefighting missions in the body or border of water areas. In such areas, it is difficult and even dangerous for human firefighters, and firefighting robots, to approach and put out the fire. Thus, the systems proposed in this paper make use of the available water source not only for suppressing the fire, but also for propelling and maneuvering themselves. The three designs are different in their ways of actuating, namely flow rate control, nozzle rotation control, and weight distribution control. The designs are first introduced. Then, mathematical models are formulated and reveal the motion characteristics of each system. A linear control framework is developed and implemented for all of them. Simulation studies were conducted to verify their motion performance and subsequently, to select the best solution. The results indicate that the weight distribution control system struggled to follow the required reference while the two other designs both provided adequate maneuverability. The nozzle rotation control system is the better one, with greater tracking results of the head part and smaller fluctuations of the water hose.

This study proposes a flying robot using waterpower and a novel weight-shifting mechanism, whose purpose is to be applied in firefighting tasks in water areas that are difficult to access and are suppressed by conventional firefighting methods. The sufficient amount of water in the area is used for propelling the robot, as well as fire suppression activity. A weight-shifting mechanism governs the weight distribution of the robot head in order to perform the robot motions. In this paper, the system’s dynamical characteristics are analyzed in detail through mathematical models. A linear-quadratic integrator (LQI) is designed for controlling the system motion. Additionally, the LQI is tuned with the genetic algorithm (GA) so that both system performance and robustness are optimally preserved. Simulation studies are carried out, in which the proposed system is compared with a cascade proportional-integral-derivative (PID) control system. The results validate the feasibility of the design and show the superiority of the proposed control system in motion performances. Moreover, the LQI-GA consumes 2.28% less water and uses 83.85% less kinetic energy of the actuator than the PID 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 paper proposes a novel nonlinear control approach for a two-axis gimbal to achieve accurate real-time tracking performance in maritime surveillance applications. For this objective, the control system must overcome system complexities and limitations, including nonlinear dynamics, coupled Euler angle-based measurements, and delay time constraints. The nonlinear backstepping controller was designed, taking into consideration the nonlinearities and system couplings to preserve the system stability. Then, an extra backstep was incorporated to minimize the control errors due to the delay time. The proposed control scheme enhances the tracking performances and expands the system’s bandwidth, which is validated in the simulations and experimental studies in comparison with a super-twisting sliding mode controller introduced in a previous study.