“Flying Car'' or “Air Taxi'' draws attention as next innovation. A lot of Flying Car concepts are proposed and their target range vary from tens to hundreds of kilometers. So, the question is how long Flying Car mission range will be, where battery has only one hundredth energy density comparing to fuel. In this paper the same formulas that can apply to both Flying Car utilizing battery and helicopter utilizing fuel are presented. These formulas are so simple but substantial that range is calculated by multiplying energy density, vehicle L/D and fuel/battery weight ratio. The key to achieve higher Flying Car L/D is how to cope with profile loss of rotary wing employed for vertical flight in cruise condition such as Uber's “Stowed Propeller''. If Uber's vehicle performance targets of L/D 16 and empty weight ratio 0.45 were achieved, the range will be 200km with today's 100Wh/kg battery and can be longer enough to compete against helicopter with next generation battery.
Recently, rotorcrafts with various configurations have been developed, and some of them have partially overlapping rotors. The ratio of the distance between the rotor axes to the rotor radius of the partially overlapping rotors is close to 1, and the value is between those of tandem rotors and coaxial rotors. And the distance between the rotor planes in the partially overlapping rotors is much less than the rotor radius. A mathematical model for the overlapping rotors during hover has been newly established. By using the model, the aerodynamic performance of the overlapping rotors has been revealed with a parameter of the distance between the rotational axes.
Space observations have been performed to acquire data related to configuration of galaxies and planets so far. Currently, space agencies and companies are looking at high pointing accuracy observation of targets in deep space. To achieve the purpose, internal disturbance suppression technologies are very important. Those internal disturbances are mainly generated by equipment on bus part of space telescopes and propagates through the structure. Among the internal disturbances, vibration and heat cause predominantly to degrade pointing accuracy of deep space observation. To suppress the vibration and heat, a contactless micro vibration isolator using the flux pinning effect has been proposed. Our proposed isolator utilizes spring-damping characteristics of the flux pinning effect to suppress vibration. Although the spring-damping characteristics is nonlinear, it is expected that the nonlinearity can be linearized for micro vibration suppression. To confirm the linearized vibration characteristics of the proposed micro vibration isolator, a vibration experiment is conducted. The experimental results are compared with numerical model. Performance of vibration suppression using linearized spring-damping characteristics is discussed in this paper.
In this paper, we introduce a newly developed general-purpose IoT module and describe its functions and characteristics. The module is reprogrammable and equipped with adequate types of I/O ports, which contributes to its high versatility. In addition, it is expected to perform high endurability in strong radiation environment and therefore the module is ready for spacecraft application. Finally, the modules are applied to a broadcast-type autonomous distributed heater control system and the new modules are confirmed to be applicable to this system.
This paper addresses the design problem of Luenberger observer-based robust iHi∞ flight controllers for aircraft motion control. Structured Linear Time-Invariant (LTI) iHi∞ controllers, which are merely sub-optimal with respect to the optimality of H∞ norm in controllers' parameter space but are attractive due to the simpler structure than full-order H∞ controllers, can be easily designed using MATLAB® hinfstruct even for LTI Parameter-Dependent (LTIPD) and Linear Parameter-Varying (LPV) systems via two-step design. That is, controller gain candidates are firstly designed as common gains for multiple LTI models selected from the LTIPD or LPV systems with specific parameter values, and their practical performance is then examined for the LTIPD or LPV systems with rigorous analysis conditions. However, hinfstruct cannot handle multiple design specifications simultaneously, thus, it is not so easy to design practical flight controllers which should meet various requirements. This paper addresses the design problem of Luenberger observer-based robust H∞ flight controllers using MATLAB® systune, and demonstrates that such controllers can be designed with observer performance optimized under a priori specified scaled-H∞ performance and controller gain constraints. The effectiveness of the controller is examined by Hardware-In-the-Loop Simulations (HILS) with JAXA's research airplane MuPAL-α.