Practical Model Construction and Stable Control of an Unmanned Aerial Vehicle With a Parafoil-Type Wing

This correspondence paper presents a framework for practical model construction and stable altitude control of an unmanned aerial vehicle with a parafoil-type wing (UAV-PW). To design a stable controller, we first construct a dynamical longitudinal model of the UAV-PW. Since there exist no aerodynamics data of the parafoil shape in our UAV-PW, aerodynamics coefficients balanced at the trimmed equilibrium are employed. The model accuracy is investigated by comparing the model outputs with the real test flight experimental data. Next, stable controller design conditions for the UAV-PW model with uncertainties are derived in terms of linear matrix inequalities (LMIs). By solving the LMI conditions, we design a stable controller that asymptotically stabilizes the UAV-PW model with the uncertainties on a considered operation domain. The experimental results demonstrate the viability of the model construction and the stable altitude control

A Waypoint Following Control Design for a Paraglider Model With Aerodynamic Uncertainty

This paper presents a waypoint following control design for a powered paraglider (PPG) model. After constructing a dynamic model with six degrees of freedom of the PPG, a dynamical lateral model around a trim equilibrium in the steady-state flight is obtained. Unknown parameters, such as the moment of inertia, the drag coefficient, etc., in the lateral model are optimized by real flight experimental data. The model output with the optimized parameters agrees with the real flight experimental data. Since the aerodynamics-related parameter, i.e., the drag coefficient, might be slightly changed even near the considered trim equilibrium, this paper considers its uncertainty in the constructed lateral model. A nonlinear controller to stabilize the lateral model (with the aerodynamic uncertainty) on a considered operation domain is designed by solving robust controller design conditions expressed in terms of linear matrix inequality. The experimental results including automatic landing demonstrate the effectiveness of the control system design framework, i.e., the model construction and the robust stable control, considering the model uncertainty

Multiobjective control of a vehicle with triple trailers

We consider the backing-up control of a vehicle with triple trailers using a model-based fuzzy-control methodology. First, the vehicle model is represented by a Takagi-Sugeno fuzzy model. Then, we employ the so-called "parallel distributed compensation" design to arrive at a controller that guarantees the stability of the closed-loop system consisted of the fuzzy model and controller. The control-design problem is cast in terms of linear matrix inequalities (LMIs). In addition to stability, the control performance considerations such as decay rate, constraints on input and output, and disturbance rejection are incorporated in the LMI conditions. In application to the vehicle with triple trailers setup, we utilize these LMI conditions to explicitly avoid the saturation of the steering angle and the jackknife phenomenon in the control design. Both simulation and experimental results are presented. Our results demonstrate that the fuzzy controller effectively achieves the backing-up control of the vehicle with triple trailers while avoiding the saturation of the actuator and "jackknife" phenomenon

Guaranteed Cost Control of Polynomial Fuzzy Systems via a Sum of Squares Approach

This paper presents the guaranteed cost control of polynomial fuzzy systems via a sum of squares (SOS) approach. First, we present a polynomial fuzzy model and controller that are more general representations of the well-known Takagi-Sugeno (T-S) fuzzy model and controller, respectively. Second, we derive a guaranteed cost control design condition based on polynomial Lyapunov functions. Hence, the design approach discussed in this paper is more general than the existing LMI approaches (to T-S fuzzy control system designs) based on quadratic Lyapunov functions. The design condition realizes a guaranteed cost control by minimizing the upper bound of a given performance function. In addition, the design condition in the proposed approach can be represented in terms of SOS and is numerically (partially symbolically) solved via the recent developed SOSTOOLS. To illustrate the validity of the design approach, two design examples are provided. The first example deals with a complicated nonlinear system. The second example presents micro helicopter control. Both the examples show that our approach provides more extensive design results for the existing LMI approach

Electroencephalogram-based control of an electric wheelchair

This paper presents a study on electroencephalogram (EEG)-based control of an electric wheelchair. The objective is to control the direction of an electric wheelchair using only EEG signals. In other words, this is an attempt to use brain signals to control mechanical devices such as wheelchairs. To achieve this goal, we have developed a recursive training algorithm to generate recognition patterns from EEG signals. Our experimental results demonstrate the utility of the proposed recursive training algorithm and the viability of accomplishing direction control of an electric wheelchair by only EEG signals

Stability of internet-based control systems with uncertainties and multiple time-varying delays

In this paper, based on remote control and local control strategy, a class of hybrid multi-rate control models with uncertainties and multiple time-varying delays is formulated and their robust stability properties are investigated. By Lyapunov-Krasovskii functions and apply it to a descriptor model transformation, some new criteria of robust stability for such Internet-based control systems are established. Numerical example and simulation are given to illustrate the effectiveness of the theoretical results

Development of a Flying Robot With a Pantograph-Based Variable Wing Mechanism

We develop a flying robot with a new pantograph-based variable wing mechanism for horizontal-axis rotorcrafts (cyclogyro rotorcrafts). A key feature of the new mechanism is to have a unique trajectory of variable wings that not only change angles of attack but also expand and contract according to wing positions. As a first step, this paper focuses on demonstrating the possibility of the flying robot with this mechanism. After addressing the pantograph-based variable wing mechanism and its features, a simulation model of this mechanism is constructed. Next, we present some comparison results (between the simulation model and experimental data) for a prototype body with the proposed pantograph-based variable wing mechanism. Both simulation and experimental results show that the flying robot with this new mechanism can generate enough lift forces to keep itself in the air. Furthermore, we construct a more precise simulation model by considering rotational motion of each wing. As a result of optimizing design parameters using the precise simulation model, flight performance experimental results demonstrate that the robot with the optimal design parameters can generate not only enough lift forces but a 155 gf payload as well

Sensor Reduction for Backing-Up Control of a Vehicle With Triple Trailers

This paper presents a cost-effective design based on sensor reduction for backing-up control of a vehicle with triple trailers. To realize a cost-effective design, we newly derive two linear-matrix-inequality (LMI) conditions for a discrete Takagi-Sugeno fuzzy system. One is an optimal dynamic output feedback design that guarantees desired control performance. The other is an avoidance of jackknife phenomenon for the use of the optimal dynamic output feedback controller. Our results demonstrate that the proposed LMI-based design effectively achieves the backing-up control of the vehicle with triple trailers while avoiding the jackknife phenomenon. More importantly, we demonstrate that the designed optimal control can achieve the backing-up control without, at least, two potentiometers that were employed to measure the relative angles (of a vehicle with triple trailers) in our previous experiments. Since the relative angles directly relate to the jackknife phenomenon, the successful control results without two potentiometers are very interesting and important from the cost-effective design point of view