The attitude control using reaction wheels as actuators has been one of the most popular ways to stabilize and repel external disturbances in aerospace devices. From the controlled change of the angular momentum rate of change using reaction wheels, it is possible to control the oscillation and direction rates of change of rigid bodies in space. Thus, the main idea of this article is to present a case study with different configurations of the well-known reaction wheel pendulum. The first is based on the classical configuration, and the second, a new one, a pendulum with two reaction wheels. For both configurations, proportional–integral–derivative controllers were designed and experimental devices were built to perform real-time controllers using low-cost hardware. The simulated and experimental results have shown that the pendulums were controlled using a simple controller in the inverted position and the results were satisfactory. Four performance indices were calculated to evaluate the results for each configuration. They showed that the pendulum with two reaction wheels worked better than the pendulum with one reaction wheel. Two actuators made it easier to move and control the pendulum in the inverted position.

Reaction wheels have been extensively used to control and stabilize a wide range of applications due to the angular momentum exchange that they provide to mechanical systems. However, there exist several limitations associated with actuator saturation and the presence of singularities that lead towards the use of different controllers and devices. Recently, a new and unusual configuration using two reaction wheels was proposed and illustrated in an inverted pendulum to drive and control it using a simple and well-known PID controller. In this context, this paper improves the previous results on the same system by proposing two more sophisticated nonlinear controllers: a nonlinear proportional-derivative and a sliding mode controller. The proof of the stability of each controller is also provided, and the asymptotic stability is proven. A friction model is experimentally updated into the differential equations of the pendulum and also included for the controllers designing. A real-time application verifies the performance of the controllers using low-cost hardware. Results based on the analysis of different performance indices highlight the improvement of applying these two nonlinear control techniques comparing to the previous paper using this configuration of actuators. INDEX TERMS Inverted pendulum, low-cost hardware, reaction wheels, sliding mode control.

The ability of multiple manned and unmanned aircraft systems to cooperatively engage and disable an aerial threat plays a decisive role in modern warfare scenarios. In this paper, we apply key methods to enable the so-called cooperative threat engagement capability among multiple networked agents, e.g., a swarm of drones, with combat and communication capabilities. In particular, this research combines AI-based decision-making and control techniques for a swarm of loyal wingman drones to coordinate efficient defense actions in a cooperative and autonomous manner. We apply these concepts in a defense scenario that is modeled to analyze the loyal wingman concept, which we consider an interesting testbed for cooperative decision-making and low-level control techniques. The investigated methods were implemented in a realistic 3D UAV simulator for demonstration and evaluation. INDEX TERMSCooperative engagement capability, loyal wingman UAV, decision making, manned-unmanned teaming, sliding mode control.

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