Pu Xie

A Bio-inspired Approach for UAV Landing and Perching

This paper describes a bio-inspired flight trajectory planning method for a UAV to approach to a target for landing and perching. It also presents the control strategy for a quadrotor UAV to track the desired flight trajectory. The desired flight trajectory is developed based on the bio-behavioral Tau theory which was established from studying the natural motion patterns of animals and human arms approaching to a fixed or moving target for capture. The method offers a fast approaching to the target and a smooth landing on the target because the motion gap is closed with a zero relative velocity and acceleration. A flight dynamics model of the UAV system is developed for simulation based analysis prior to developing a hardware prototype and flight experiment. Simulation results are presented to show the resulting bio-inspired motion trajectories for final approaching and landing, and attitude control.

Bioinspired 4D Trajectory Generation for a UAS Rapid Point-to-Point Movement

A bioinspired trajectory generation approach for Unmanned Aerial System (UAS) rapid Point-to-Point (PTP) movement was presented. The approach was based on general tau theory developed by biologists from observing and studying the behavior of birds and some other animals. We applied the bioinspired approach to the rapid PTP movement problem of a rotary UAS and derived two different trajectory planning strategies, namely, the tau coupling strategy and the intrinsic tau gravity guidance strategy. Based on general tau theory, according to the dynamic model of UAS, we presented a new strategy named intrinsic tau jerk guidance which can fit the movement that the initial acceleration of the UAS is zero. With new strategies, flight trajectory generation examples with a UAS were presented. The kinematics and dynamics analyses of the UAS for rapid PTP movement were presented with simulation results which show that the generated trajectories were feasible.

Bio-inspired Trajectory Generation for UAV Perching Movement Based on Tau Theory

This paper offers a bio-inspired trajectory generation method for UAV/MAV perching (i.e., the final approach to, and landing on, a target). The method is based on tau theory, which was established based on the study of the natural motion patterns of animals (including humans) when they approach a fixed or moving object for perching or capturing prey. In our research, tau theory is applied to the trajectory generation problem of an air vehicle for perching on a target object. Three bio-inspired strategies, namely the tau in the action gap strategy, the tau coupling strategy and the intrinsic tau gravity strategy are studied for perching tasks. A key parameter of the method inspired by biological systems is discussed. Two perching scenarios, one from a flight state (with non-zero initial velocity) and one from a hovering state (with zero initial velocity), are studied. Numerical simulations with a rotary vehicle are presented as examples to demonstrate the performance of the proposed approach. The simulation results show that the resulting flight trajectories meet all the desired requirements for the vehicle in perching on an object.

Bio-inspired trajectory generation for UAV perching

This paper represents a bio-inspired trajectory generation (path planning) method for UAV perching. The method is based on the tau theory which was established from studying the natural motion behaviors when animals (including humans) approaching and catching a fixed or moving object. In our research, the tau theory is applied to the trajectory generation problem of a UAV perching on a target object. Two perching scenarios have been studied, one from a flight state (with non-zero initial velocity) and one from a hovering state (with zero initial velocity). Three strategies, namely, perching with a straight-line trajectory, perching with pitch angle coupling, and perching with pitch/yaw angular coupling, are demonstrated with each of the two scenarios. The simulation results show that the resulting flight trajectories meet all the desired requirements for a rotary UAV to perch on an object.

Development of a Small UAV with Autopilot Capability

It is challenging to develop and test autonomous unmanned aerial vehicles (UAVs) because of the multidisciplinary nature of the work and the paramount safety requirement. A UAV system with autopilot capability was developed by a group of students at New Mexico State University. The UAV system was built based on an originally radio controlled (RC) Raptor 90 helicopter and a commercial-off-the-shelf autopilot package MP2128 HELI . The development work was focused on the components selection, interfaces design, system integration and testing. Several problems regarding vibration isolation, electromagnetic interference shielding and safe testing of the system have been solved. This paper describes the development work including the system architecture, mechanical and electrical components design, system integration, and some preliminary results of the system test.

Development of a Special Inertial Measurement Unit for UAV Applications

Dynamics modeling is becoming more and more important in the development and control of unmanned aerial vehicles (UAV). An accurate model of a vehicle requires good knowledge of the dynamics properties and motion states, which are usually estimated with the help of integrated inertial measurement units (IMUs). This work develops a special six degrees of freedom IMU, which has the capability of measuring the angular accelerations. This paper introduces the design of the new IMU along with its sensor models and calibration procedures. The work introduces two experimental methods to verify the calibrated IMU readings. The IMU was designed to support an on-line methodology to estimate the parameters of UAV’s dynamics model that is currently being developed by the authors. [DOI: 10.1115/1.4007122]

Test of a Special Inertial Measurement Unit using a Quadrotor Aircraft

This paper discusses the calibration and test of a special Inertial Measurement Unit (IMU) using a Quadrotor aircraft. The IMU was designed and built in house, which has the capability of estimating the angular acceleration in addition to the measurement of angular velocity and linear accelerations. Among the different types of existing UAVs, a Quadrotor was chosen as a platform to test the IMU because its simplicity in geometry structure and control. Before the IMU can be practically used for real UAV flight control, a full 6-DOF flight test must be successfully done. This work reported in this paper addresses this need. For safety, the flight tests are performed in a gravity-balanced test-stand which was also designed in house for facilitating safe test of micro UAVs.

Development of an autonomous unmanned aerial vehicle using gas-powered RC helicopter

This paper describes the development of a small unmanned aerial vehicle (UAV) with autonomous flight capability. It is the result of integrating a commercial off-the-shelf autopilot system with a low-cost gas-powered RC helicopter. Researchers face several challenges when developing UAVs using gas-powered RC helicopters. To avoid the corruption of the structural vibration to the avionics hardware system, an innovative vibration isolation technique is developed to mechanically isolate the vibrations from the gas engine and rotors. Furthermore, a dynamics model for the vehicle is created to support the autonomous flight control development work. Further, a loss-recover method using Kalman filter is employed for estimating the attitude and position statuses when GPS signal is lost. Several other key challenges related to electromagnetic interference shielding and safe flight testing are also effectively solved in the project. The integration work has been completed and the test flights done so far show that the developed autonomous UAV works well under the integration of the mechanical system, electronic system, and controller software.

Verification of a special inertial measurement unit using a Quadrotor aircraft

Purpose – Calibration and 6-DOF test of a unique inertial measurement unit (IMU) using a Quadrotor aircraft. The purpose of this paper is to discuss the above issue. Design/methodology/approach – An IMU with the special capability of measuring the angular acceleration was developed and tested. A Quadrotor aircraft is used as 6-DOF test platform. Kinematics modeling of the Quadrotor was used in the determination of the Euler angles, while Dynamics modeling aided in the design the closed loop controller. For safety, the flight test was performed on a 6-DOF constrained reduced-gravity test stand. Findings – The developed IMU is suitable for measuring states and its time derivatives of mini UAVs. Not only that but also a simple control algorithm can be integrated in the same processing unit (a 32 microcontroller in this case). Originality/value – The tested IMU as well as the safety constrained test techniques are unique.

Grasping Analysis of a Bio-Inspired UAV/MAV Perching Mechanism

This paper presents the grasping analysis of a bio-inspired UAV/MAV perching mechanism designed at New Mexico State University. The mechanism is composed of a cable-driven leg mechanism and two cable-driven underactuated three-digit feet. The mechanical design was based on the analysis of the anatomy of bird legs and feet. In this paper, the grasping stable condition of the mechanical foot is studied through a quasi-static analysis, which models the relationship between the actuated forces of a digit and the contact forces on each phalanx. Using this model, we can understand the foot’s stable grasping configuration regions. Furthermore, the contact behavior between each foot and the perched object is evaluated using the Hertz contact force model on SimMechanics. The static analysis conclusion and the contact analysis show that this paper has given a fundamental contribution for the designed artificial foot used in developing UAV/MAV perching technology.Copyright