Roll, Pitch and Yaw Torque Control for a Robotic Bee

In the last decade, the robotics community has pushed to develop increasingly small, autonomous flapping-wing robotic vehicles for a variety of civilian and military applications. The miniaturization of these vehicles has pushed the boundaries of technology in many areas, including electronics, artificial intelligence, and mechanics; as well as our understanding of biology. In particular, at the insect scale, fabrication, actuation, and flight control of a flapping-wing robot become especially challenging. This thesis addresses these challenges in the context of the “RoboBee” project, which has the goal of creating an autonomous swarm of at-scale robotic bees. A 100mg robot with a 3cm wingspan capable of generating roll, pitch and yaw torques in the range of $\pm 1\mu Nm$ by using a large, central power actuator to flap the wings and smaller control actuators to steer is presented. A dynamic model is used to predict torque generation capabilities, and custom instrumentation is developed to measure and characterize the vehicle’s control torques. Finally, controlled flight experiments are presented, and the vehicle is capable of maintaining a stable pitch and roll attitude during ascending vertical flight. This is the first successful controlled flight of a truly insect-scale flapping-wing robot.Engineering and Applied Science

Design and Control of Flapping Wing Micro Air Vehicles

Flapping wing Micro Air Vehicles (MAVs) continues to be a growing field, with ongoing research into unsteady, low Re aerodynamics, micro-fabrication, and fluid-structure interaction. However, research into flapping wing control of such MAVs continues to lag. Existing research uniformly consists of proposed control laws that are validated by computer simulations of quasi-steady blade-element formulae. Such simulations use numerous assumptions and cannot be trusted to fully describe the flow physics. Instead, such control laws must be validated on hardware. Here, a novel control technique is proposed called Bi-harmonic Amplitude and Bias Modulation (BABM) which can generate forces and moments in 5 vehicle degrees of freedom with only two actuators. Several MAV prototypes were designed and manufactured with independently controllable wings capable of prescribing arbitrary wing trajectories. The forces and moments generated by a MAV utilizing the BABM control technique were measured on a 6-component balance. These experiments verified that a prototype can generate uncoupled forces and moments for motion in five degrees of freedom when using the BABM control technique, and that these forces can be approximated by quasi-steady blade-element formulae. Finally, the prototype performed preliminary controlled flight in constrained motion experiments, further demonstrating the feasibility of BABM

A Novel Degree of Freedom in Flapping Wings Shows Promise for a Dual Aerial/Aquatic Vehicle Propulsor

Ocean sampling for highly temporal phenomena, such as harmful algal blooms, necessitates a vehicle capable of fast aerial travel interspersed with an aquatic means of acquiring in-situ measurements. Vehicle platforms with this capability have yet to be widely adopted by the oceanographic community. Several animal examples successfully make this aerial/aquatic transition using a flapping foil actuator, offering an existence proof for a viable vehicle design. We discuss a preliminary realization of a flapping wing actuation system for use in both air and water. The wing employs an active in-line motion degree of freedom to generate the large force envelope necessary for propulsion in both fluid media.Comment: Accepted version of paper for ICRA 2015, 8 pages, 9 figures; Proceedings of IEEE International Conference on Robotics and Automation (ICRA), pp. 5830 - 5837, Seattle WA, 201

Aerial Vehicles

This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space

Hybrid power system for Micro Air Vehicles

Today Micro Air Vehicles are in need of a good power source that would enable them longer flight time and various functionalities. This work is focused on to this problem. A possible solution that is offered in this study is implementing a hybrid power system consisting of battery and supercapacitor (SCAP). The proposed hybrid power system was tested on an existing MAV platform (Cheerson CX-10). A separate hybrid power printed circuit board (PCB) was designed and manufactured. For experimental and system verification purposes, the PCB was not sized for on-board flight. The hybrid power PCB was connected to MAV through light power wires. To eliminate flight inconsistency, a testbed was constructed from plywood. The quadcopter was controlled using a joystick. In total, three experimental tests were conducted. In the first experiment, SCAP charge time was evaluated and compared to the calculated value. The results were very close. In the second and third experiments, MAV flight time was collected for both battery and hybrid powered MAVs for two different flight patterns. The first pattern was flying 10 seconds at low speed using battery power and 10 seconds at average speed using SCAPs power. The second pattern was flying at a fixed average speed: 10 seconds with battery and 5 seconds with SCAP power. For all the experiments, six new fully charged batteries were used. In every flight, in order to reduce the risk of decreasing battery performance, battery voltage was controlled so as not to exceed 75% depth of discharge. As soon as it reached 75% discharge rate, the flight was discontinued. At the end of the experiments, statistical data analysis was performed. The study hypothesis that the hybrid powered MAV flight time is more than the battery powered MAV flight time was proven

Aquatic escape for micro-aerial vehicles

As our world is experiencing climate changes, we are in need of better monitoring technologies. Most of our planet is covered with water and robots will need to move in aquatic environments. A mobile robotic platform that possesses efficient locomotion and is capable of operating in diverse scenarios would give us an advantage in data collection that can validate climate models, emergency relief and experimental biological research. This field of application is the driving vector of this robotics research which aims to understand, produce and demonstrate solutions of aerial-aquatic autonomous vehicles. However, small robots face major challenges in operating both in water and in air, as well as transition between those fluids, mainly due to the difference of density of the media. This thesis presents the developments of new aquatic locomotion strategies at small scales that further enlarge the operational domain of conventional platforms. This comprises flight, shallow water locomotion and the transition in-between. Their operating principles, manufacturing methods and control methods are discussed and evaluated in detail. I present multiple unique aerial-aquatic robots with various water escape mechanisms, spanning over different scales. The five robotic platforms showcased share similarities that are compared. The take-off methods are analysed carefully and the underlying physics principles put into light. While all presented research fulfils a similar locomotion objective - i.e aerial and aquatic motion - their relevance depends on the environmental conditions and supposed mission. As such, the performance of each vehicle is discussed and characterised in real, relevant conditions. A novel water-reactive fuel thruster is developed for impulsive take-off, allowing consecutive and multiple jump-gliding from the water surface in rough conditions. At a smaller scale, the escape of a milligram robotic bee is achieved. In addition, a new robot class is demonstrated, that employs the same wings for flying as for passive surface sailing. This unique capability allows the flexibility of flight to be combined with long-duration surface missions, enabling autonomous prolonged aquatic monitoring.Open Acces