Yingping He

Autonomous homing control of a powered parafoil with insufficient altitude

In order to realize safe and accurate homing of a powered parafoil under the condition of insufficient initial altitude, a multiphase homing path is designed according to the flight characteristics of the vehicle. With consideration that the traditional control methods cannot ensure the quality of path following because of the nonlinear, large inertial and longtime delay existed in the system and strong disturbances in a complex environment, a homing controller, composed of the vertical and horizontal trajectory tracking controllers, is designed based on active disturbance rejection control (ADRC). Then autonomous homing simulation experiment of the powered parafoil with insufficient altitude is carried on in a windy environment. The simulation results show that the planned multiphase homing trajectory can fulfill the requirements of fixed-point homing and flare landing; the designed homing controller can overcome the influences of uncertain items of the internal and external disturbances, track the desired homing path more rapidly and steadily, and possesses better control performances than traditional PID controllers.

Modeling and Control of a Powered Parafoil in Wind and Rain Environments

A novel modeling method, based on computational fluid dynamics (CFD) to simulate a parafoil flying in rain and wind environments, is proposed. Then, the dynamic model of the powered parafoil in the complex environment is established on the basis of revised aerodynamic equations. By introducing path-following controllers based on active disturbance rejection control (ADRC), horizontal and longitude trajectory tracking of the powered parafoil in realistic environments are simulated. Results verify the effectiveness of the model and control methods.

Soft landing control of unmanned powered parafoils in unknown wind environments

For autonomous landing powered parafoils, the ability to perform a final flare maneuver against the wind direction can generate a considerable reduction of lateral and longitudinal velocities at impact, enabling a soft landing for a safe delivery of sensible loads. To realize accurate, soft landing in the unknown wind environment, an in-flight wind identification algorithm is first proposed. The wind direction and speed can be obtained online by only using the GPS sampling data based on the recursive least square method. Moreover, the 3D trajectory tracking strategy for the powered parafoil is also established, which is globally asymptotically stable. Furthermore, the lateral trajectory tracking controller and longitudinal altitude controller based on active disturbance rejection control are presented, respectively. Eventually, results from simulations demonstrate that the proposed landing control method can effectively realize accurate soft landing in unknown wind environments with the in-flight wind identification algorithm applied in the trajectory tracking process.

Autonomous homing control of a parafoil system based on ADRC

In order to realize safe and accurate homing of a parafoil system, a multiphase homing path planning method is proposed according to flight characteristics of the vehicle. And a new particle swarm optimization algorithm based on chaos searching (CPSO) is applied as a tool to optimize the designed path. With consideration that the traditional control methods cannot ensure the precision of path following for the problem of nonlinear, large inertial, long time delay existed in the system and strong disturbances in its flying environment, a homing controller is designed based on active disturbance rejection control (ADRC). The simulation results demonstrate that the multiphase homing trajectory can fulfill the requirements of fixed-point and upwind landing; the designed homing controller can track the planned homing path rapidly and steadily, overcome the influences of uncertain items of model and external disturbances, and possesses better robustness and control performances than the PID controller.

Modeling and Simulation of Parafoil Systems in Wind Fields

Parafoil systems are a kind of flexible wing vehicle. In view that the vehicle flying at low altitude is more susceptible to wind fields, and considering that the parafoil canopy and the payload are regarded as rigid connection, a six degrees of freedom (DOF) dynamic model is established according to the Kirchhoff motion equation, which consists of three DOF for translational motion and three DOF for rotational motion. Moreover, the effects of wind fields on its flight performances are also discussed. The motion characteristics of parafoil systems under the horizontal constant wind field are studied by numerical simulation. Simulation results demonstrate that the established model can accurately characterize dynamic performances of parafoil systems in wind fields, which is high valuable in engineering applications.