This paper deals with a design method of an adaptive control system for a twin-rotor helicopter. The almost strictly positive real (ASPR) based adaptive output feedback control has attracted a great deal of interest as a robust control system with simple structure. Unfortunately, however, the twin-rotor helicopter does not satisfy the ASPR conditions and also it has a nonlinearity. In this paper, adaptive parallel feedforward compensator (PFC) is adopted to overcome this problem, and adaptive control system will be configured. Also, the usefulness of the control system will be confirmed through a numerical simulation.
In this paper, we propose a design of the fault tolerant adaptive control system for the input redundant linear plants which has m input channels with model reference adaptive control scheme. A feature of the proposed control system is to introduce the adaptive allocator which distributes and injects external signals into the plant. We derive adaptive law which ensures stability of output of the plant which has up to (m−1) faults, using a suitable Lyapunov function. Through a numerical simulation, we show the stability and fault-tolerance of the designed MRAC.
This paper deals with formation control of mobile robots whose actuators are saturated. Each mobile robot has two independent wheels that are driven by their rotational speeds as control input. Each mobile robot also has a virtual vehicle and consensus of all of the virtual vehicles enables us to achieve formation of the mobile robots. If each mobile robot has saturation on their rotational speeds of the wheels, standard consensus protocols cannot achieve formation of the mobile robots as well as consensus of the virtual vehicles. To cope with this issue, this paper discusses a time-varying gain in the consensus protocol that is introduced so as not to saturate the rotational speeds. This paper also proposes a design method of the time-varying gains which are not common for the mobile robots and are able to improve the convergence speed of formation. The paper finally shows an experiment of formation control with hand made mobile robots as well as numerical examples.