Robotic Flight Research Articles

Avian-inspired embodied perception in biohybrid flapping-wing robotics

Avian feather intricate adaptable architecture to wing deformations has catalyzed interest in feathered flapping-wing aircraft with high maneuverability, agility, and stealth. Yet, to mimic avian integrated somatic sensation within stringent weight constraints, remains challenging. Here, we propose an avian-inspired embodied perception approach for biohybrid flapping-wing robots. Our feather-piezoelectric mechanoreceptor leverages feather-based vibration structures and flexible piezoelectric materials to refine and augment mechanoreception via coupled oscillator interactions and robust microstructure adhesion. Utilizing convolutional neural networks with the grey wolf optimizer, we develop tactile perception of airflow velocity and wing flapping frequency proprioception. This method also senses pitch angle via airflow direction and detects wing morphology through feather collisions. Our low-weight, accurate perception of flapping-wing robot flight states is validated by motion capture. This investigation constructs a biomechanically integrated embodied perception system in flapping-wing robots, which holds significant promise in reflex-based control of complex flight maneuvers and natural bird flight surveillance.

Bistable click mechanism for dipteran flight robot

The flight mechanism of the dipteran insects is commonly used to design the flapping robot. However, the nonlinear dynamics of the buckling click mechanism of the flapping robot with bistability still unclear. In this paper, a novel flapping robot model with the click mechanism proposed based on the bistability of snap-through buckling. The nonlinear governing equations of the flight robot are obtained by using the Euler–Lagrange equation. The nonlinear potential energy, moment of the elastic force, equilibrium bifurcation, as well as equilibrium stability are investigated to show the bistable characteristics. The transitional and persistent sets of bifurcation regions in the parameter plane and the corresponding phase portraits are obtained with single and double well behaviors. Then, the periodic response of the free flight are defined by the analytical solution of three kinds of elliptical functions, as well as the amplitude frequency responses are investigated by numerical integration. Based on the topological equivalent, the chaotic thresholds of the homo-clinic and heteroclinic orbits for the chaotic vibration of the perturbed robot system are derived. Finally, the prototype of nonlinear flapping robot is manufactured and the experimental system is setup. The nonlinear static moment of force curves, periodic response and dynamic flight vibration of dipteran robot system are carried out. It is shown that the test results are agree well with the theoretical analysis and numerical simulation. Those results have the potential application for the structure design of the efficient flight robot.

Humanzentrierte Implementierung von (teil-)autonomen Drohnen

Abstract The industrial use of drones is constantly increasing due to the transition from Industry 4.0 to Industry 5.0. A prerequisite for the concrete implementation is the legal and organizational risk assessment of flight robotics. The core of the article is a systematic overview of relevant human-centered risk factors for the adaptation of drones in organizations. Based on the proposed risk taxonomy, design options for human-drone interaction and an overview of key questions for risk assessment are presented.

A Safety-Oriented Motion Cueing Algorithm for a Serial Robotic Flight Simulator Using a Predictive Neural Network Reference Governor

A Safety-Oriented Motion Cueing Algorithm for a Serial Robotic Flight Simulator Using a Predictive Neural Network Reference Governor

Robot Pilot: A New Autonomous System toward Flying Manned Aerial Vehicles

The robot pilot is a new concept of a robot system that pilots a manned aircraft, thereby forming a new type of unmanned aircraft system (UAS) that makes full use of the platform maturity, load capacity, and airworthiness of existing manned aircraft while greatly expanding the operation and application fields of UASs. In this research, the implementation and advantages of the robot pilot concept are discussed in detail, and a helicopter robot pilot is proposed to fly manned helicopters. The robot manipulators are designed according to the handling characteristics of the helicopter-controlling mechanism. Based on a kinematic analysis of the robot manipulators, a direct-driving method is established for the robot flight controller to reduce the time delay and control error of the robot servo process. A supporting ground station is built to realize different flight modes and the functional integration of the robot pilot. Finally, a prototype of the helicopter robot pilot is processed and installed in a helicopter to carry out flight tests. The test results show that the robot pilot can independently fly the helicopter to realize forward flight, backward flight, side flight, and turning flight, which verifies the effectiveness of the helicopter robot pilot.

Development of a Full Orientation Flight Robotics: Dynamics Modeling, Analysis, and Control Design

Development of a Full Orientation Flight Robotics: Dynamics Modeling, Analysis, and Control Design

FireFly: An Insect-Scale Aerial Robot Powered by Electroluminescent Soft Artificial Muscles

Light production in natural fireflies represents an effective and unique method for communication and mating. Inspired by bioluminescence, we develop a 650 mg aerial robot powered by four electroluminescent (EL) dielectric elastomer actuators (DEAs) that have distinct colors and patterns. To enable simultaneous actuation and light emission, we embed EL particles in a DEA that has highly transparent electrodes. During robot flight, a strong ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&gt;$</tex-math></inline-formula> 40 V/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m) and high frequency (400 Hz) electric field is generated within the DEA, exciting the EL particles to emit light. Compared to a regular DEA, our new design and fabrication methods require small additional weight (2.4%) and actuation power (3.2%) without adversely impacting the DEA’s output power or lifetime. We further develop a position and attitude tracking method using vision-based color detection. We demonstrate a series of closed-loop flights and compare camera-tracked results with that of the state-of-the-art Vicon motion tracking system. The root-mean-square (rms) position and attitude errors are 2.55 mm and 2.60 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> , respectively. This work illustrates a novel and effective design for communication and motion tracking in extreme payload-constrained microscale aerial systems, and it further shows the potential of achieving coordinated swarm flights without using well-calibrated in door tracking systems.

The Flight Mechanism of a Bird-like Flapping Wing Robot at a Low Reynolds Number

The flight mechanism of a bird-like flapping wing robot at a low Reynolds number was studied in this study for improving the robot performances. Both the physical model and the kinematic model were first established. The dynamic model of the robot at a low Reynolds number was built with the RANS (Reynolds-averaged Navier-Stokes) equations and the Spalart-Allmaras turbulence model. The flight experiments were carried out and the results were discussed. Lift and drag coefficient curves show that it generates upward lift and forward thrust in the phase that the wing flaps downwards, the rate of the coefficient curves is the biggest when the flapping direction changes. Pressure contours indicate that small vortexes with high pressure values appear at the wing edges. There are four velocity vortex groups in total at the front and back of the wing in the velocity contours. Some methods for improving the robot flight efficiency and the robot strength as well as the stitching position of the robot skin have been obtained from the above results. The methods provide the important guidance for the stable flights of the flapping wing robot with the high efficiency.

Free as a Bird: Event-Based Dynamic Sense-and-Avoid for Ornithopter Robot Flight

Autonomous flight of flapping-wing robots is a major challenge for robot perception. Most of the previous <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sense-and-avoid</i> works have studied the problem of obstacle avoidance for flapping-wing robots considering only static obstacles. This letter presents a fully onboard dynamic <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sense-and-avoid</i> scheme for large-scale ornithopters using event cameras. These sensors trigger pixel information due to changes of illumination in the scene such as those produced by dynamic objects. The method performs <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">event-by-event</i> processing in low-cost hardware such as those onboard small aerial vehicles. The proposed scheme detects obstacles and evaluates possible collisions with the robot body. The onboard controller actuates over the horizontal and vertical tail deflections to execute the avoidance maneuver. The scheme is validated in both indoor and outdoor scenarios using obstacles of different shapes and sizes. To the best of the authors’ knowledge, this is the first event-based method for dynamic obstacle avoidance in a flapping-wing robot.

Free as a Bird: Event-based Dynamic Sense-and-Avoid for Ornithopter Robot Flight

Free as a Bird: Event-based Dynamic Sense-and-Avoid for Ornithopter Robot Flight

Momentum-Based Extended Kalman Filter for Thrust Estimation on Flying Multibody Robots

Effective control design of flying vehicles requires a reliable estimation of the propellers’ thrust forces to secure a successful flight. Direct measurements of thrust forces, however, are seldom available in practice and on-line thrust estimation usually follows from the application of fusion algorithms that process on-board sensor data. This letter proposes a framework for the estimation of the thrust intensities on flying multibody systems that are not equipped with sensors for direct thrust measurement. The key ingredient of the proposed framework is the so-called centroidal momentum of a multibody system, which combined with the propeller model. It enables the design of Extended Kalman Filters (EKF) for on-line thrust estimation. The presented approach tackles the additional complexity in thrust estimation due to the possibly <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">large</i> number of degrees of freedom of the system and uncertainties in the propeller model. For instance, a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">covariance scheduling</i> approach based on the turbines RPM error is proposed to ensure a reliable estimation even in case of turbine failures. Simulations are presented to validate the proposed algorithm during robot flight. Moreover, an experimental setup is designed to evaluate the accuracy of the estimation algorithm using iRonCub, a jet-powered humanoid robot, while standing on the ground.

Realization of Wing with Airfoil Shape using Balloon and Development of Flapping Flight Robot using Balloon Wings

Realization of Wing with Airfoil Shape using Balloon and Development of Flapping Flight Robot using Balloon Wings

A Study on Design and Development of Large-sized Flapping Flight Robot

A Study on Design and Development of Large-sized Flapping Flight Robot

Scaling of the performance of insect-inspired passive-pitching flapping wings.

Flapping flight using passive pitch regulation is a commonly used mode of thrust and lift generation in insects and has been widely emulated in flying vehicles because it allows for simple implementation of the complex kinematics associated with flapping wing systems. Although robotic flight employing passive pitching to regulate angle of attack has been previously demonstrated, there does not exist a comprehensive understanding of the effectiveness of this mode of aerodynamic force generation, nor a method to accurately predict its performance over a range of relevant scales. Here, we present such scaling laws, incorporating aerodynamic, inertial and structural elements of the flapping-wing system, validating the theoretical considerations using a mechanical model which is tested for a linear elastic hinge and near-sinusoidal stroke kinematics over a range of scales, hinge stiffnesses and flapping frequencies. We find that suitably defined dimensionless parameters, including the Reynolds number, Re, the Cauchy number, Ch, and a newly defined 'inertial-elastic' number, IE, can reliably predict the kinematic and aerodynamic performance of the system. Our results also reveal a consistent dependency of pitching kinematics on these dimensionless parameters, providing a connection between lift coefficient and kinematic features such as angle of attack and wing rotation.

Autonomous Chemical-Sensing Aerial Robot for Urban/Suburban Environmental Monitoring

This paper describes the development of an autonomous chemical-sensing aerial robotic system for environmental monitoring in urban and suburban areas. The robot is equipped with a high-performance chemical sensor that identifies and quantifies chemical agents, enabling applications, such as chemical mapping, source localization, and estimation. To enable collision-free monitoring in areas with obstacles, such as in urban and suburban environments where buildings, trees, and other structures pose a challenge, a potential-field algorithm that incorporates past actions is used. A custom-designed ground station for controlling the robot, and planning and visualizing environmental data in real time is described. An empirical method is used to maximize the robot's flight time for improved effective operating range and to provide a safe operating standoff distance. Finally, two outdoor chemical dispersion experiments are conducted to demonstrate the capabilities of the autonomous airborne chemical-sensing system, where results show effective mapping of a propane gas leak.

Online control programming algorithm for human–robot interaction system with a novel real-time human gesture recognition method

This article proposes an online control programming algorithm for human–robot interaction systems, where robot actions are controlled by the recognition results of gestures performed by human operators based on visual images. In contrast to traditional robot control systems that use pre-defined programs to control a robot where the robot cannot change its tasks freely, this system allows the operator to train online and replan human–robot interaction tasks in real time. The proposed system is comprised of three components: an online personal feature pretraining system, a gesture recognition system, and a task replanning system for robot control. First, we collected and analyzed features extracted from images of human gestures and used those features to train the recognition program in real time. Second, a multifeature cascade classifier algorithm was applied to guarantee both the accuracy and real-time processing of our gesture recognition method. Finally, to confirm the effectiveness of our algorithm, we selected a flight robot as our test platform to conduct an online robot control experiment based on the visual gesture recognition algorithm. Through extensive experiments, the effectiveness and efficiency of our method has been confirmed.

Study of Orientation Control for a Wheeled Jumping Robot in the Flight Phase of Motion

The work studies the flight phase (a part of jumping motion) of a jumping robot. The robot consists of the body with wheeled base and a jump booster module installed in the body. The jump booster module allows the robot to accelerate in a given direction up to a predetermined speed, allowing to control the velocity of the robot at the moment when it breaks contact with the supporting surface. The goal of this study is to develop a control system for the robot’s wheels, allowing to use their inertial properties to control the robot orientation at the moment of landing. This is achieved by controlling the wheels’ orientation throughout the duration of the motion. The goal of controlling the orientation of the robot at the moment of landing is to be able to land on all four wheels and avoid tipping over. The paper studies the supporting surfaces (from which the robot jumps and to which the robot lands) described by piecewise linear functions, including a horizontal and slopped linear sub-functions. In this work, four types of supporting surfaces were distinguished, which the distinction based on the slope of the mentioned about sub-function. Another varying parameter is the point where two sub-functions connect. For the purpose of this study a kinematic and dynamic model of the robot were developed, and a control system design was proposed. The proposed control system includes a trajectory planner that allows to plan the robot’s motion resulting in the desired orientation of the robot’s body at the moment of landing. This problem was formulated as an optimization problem. Simulation results showed the dependencies between the three supporting surface parameters (two angles describing linear sub-functions and the point where the sub-functions intersect) and the duration of the robot flight, the achieved velocities of the robot’s wheels and required motor torques. The influence of those parameters on the maximal and minimal values of the wheels’ angular velocities achieved during the flight were demonstrated. This could be used in designing this type of robots, in particular it could help to set specifications for the robot’s wheel motors.

Implementation Analysis of a Washout Filter on a Robotic Flight Simulator - a Case Study

This paper presents a detailed analysis about the implementation of a washout filter on the SIVOR (Simulador de Voo Robotico – Robotic Flight Simulator) project. The main objective of this project is to develop, on an anthropomorphic robot, a flight simulator which can be used as an Engineering Development System (EDS) and a pilot training platform, capable of providing feelings the pilot would only have in more intensive maneuvers, such as losses/gains of G in aircraft flight tests. The SIVOR project also has the objective of providing a cost-efficient and flexible tool that can be used during the design phases of aircrafts. One of the demanded features of such simulator is a representative behavior of its motion system, which is achieved by an adequate implementation of the washout filter. To the best knowledge of the authors, there are no works in the literature that present a detailed discussion about the implementation of a classical washout filter in such flight simulator, especially when the translational channel is used to its limits. Experimental results to support the proposed solutions are presented herein.

Study on large flapping flight robot

Study on large flapping flight robot

Development of automatic compression and release device of jumping leg mechanism of bird type flight robot

Development of automatic compression and release device of jumping leg mechanism of bird type flight robot