Takehiro Higuchi

Collision avoidance control law of a helicopter using information amount feedback

Utilization of helicopter in urban area is increasing because of its special flight performance. Collision avoidance guidance will play an important role in the future guidance of helicopters. All information of other aircraft is not always available for collision avoidance due to climate conditions or communication problems. Helicopter has to avoid other helicopter under such uncertain information conditions. This paper proposes that a controller uses the information amount as same as physical values. The helicopter changes the flight course to increase the information amount using dynamics of information. Collision avoidance law is adopted when approaching helicopters is recognized. Avoidance is to increase the minimum distance between two helicopters. Numerical simulations show that the helicopter using the information amount avoids the approaching one with safe distance.

Delayed Feedback Control for Flow around Wing using Plasma Synthetic Jet Actuator

Flow on an airfoil was investigated with plasma synthetic jet actuator. Plasma synthetic jet actuator is a flow control device which is composed of electrodes with A.C. signal, using electrohydrodynamic effect and induces a flow around the electrodes. From the characteristics of electrical device, plasma synthetic jet actuator has some important advantages; for example, miniaturization, maintenance free, and easy to control. From these characteristics, it is effective to apply flow control around an airfoil with plasma synthetic jet actuator. In this study, the behavior of the plasma synthetic jet actuator around an airfoil is observed by experiment. A NACA0012 airfoil with plasma synthetic jet actuator is set in the wind tunnel. The wake velocity behind air foil is measured with and without the actuator. Experimental result with the Delayed Feedback Control for the flow control system is shown in this paper. The results show good improvement for the plasma synthetic jet actuator to reduce drag in the high angle of attacks.

Performance of capsule-type micro actuator using hydrogen storage alloys

Capsule-type micro actuator driven by the volume change of hydrogen storage alloys (HSA-CMA) was proposed to be applied as an actuator mounted on the joints of the super multilink manipulator to capture space debris. This actuator consists of a hollow sphere frame made of aluminum, a membrane of hydrogen storage alloys and a valve, and is compact and lightweight. The aim of this study was to evaluate the availability of HSA-CMA. Finite element analyses were performed to investigate the actuator displacement and the generating force as the static performance, and the obtained static performances were compared with that of other smart actuators. The analysis on the actuator displacement led to the design map of HSA-CMA. The comparison result suggests that HSA-CMA has the actuator displacement and the generating force as well or better than other smart actuators and that it is suitable for use in space.Copyright

Capturing simulation of space debris with super multi-link space manipulator

Space debris became one of the difficulties for mankind to utilize the space environment. Among the variable efforts to the debris problem, the development of technology for the active debris removal (ADR) is especially imperative. This paper is on the motion simulation of debris capture manipulator for ADR with large number of links. Light weight actuator using hydrogen storage alloy is developed for use in outer space as an actuator for the manipulator. The controllable time with the extended resolved motion rate control was examined past study. In this paper, to research the movement of the debris in the end-effector, the simple random collision model was established. Based on the results from this model, the aspects for the control of the end-effector to lower the relative velocity of debris in the controllable time is shown.

Single-axis simulation of state-feedback controller with bang-bang control for inchworm mobile mechanism

In this paper, we describe the design of a precise 3-axial servo controller for an inchworm mobile mechanism and the simulation result of 1-axial control for validating the design. The inchworm mobile mechanism is composed of 6 piezoelectric actuators (PAs) and a pair of electromagnets (EMs). If one EM is fixed to a ferromagnetic floor, then another EM can position the X, Y, and Θ axes by 6 PAs. In a previous study, we have developed 3-axial proportional-integral-derivative (PID) controls with a 50 nm resolution for the mechanism with 4 linear encoders to measure the 3DoF motion of the free magnet precisely, however, we concluded that we require over 100 ms of settling time because of mutual coupling effects among the X, Y, and θ axes when using the PID controller. To be robust against the disturbance and also reduce settling time, we developed a new servo controller in this study. To achieve sufficient working efficiency, we aimed at establishing of 3-axial servo control on the nanometer scale that can realize a ±0.5 μm positioning repeatability, and less than 10 ms of settling time over a 50 μm×50 μm positioning range.

Deformation behavior of capsule-Type micro actuator using palladium

Deformation behavior of a capsule-type micro actuator using palladium as a hydrogen storage alloy was investigated. The capsule-type micro actuator using hydrogen storage alloys (HSA-CMA) drives by the volume change of the hydrogen storage alloy induced by the absorption and discharge of hydrogen gas. It was developed as a compact, lightweight and energy-saving actuator mounted on the super multi-link manipulator to capture space debris. In the present work, a palladium foil was used as the hydrogen storage alloy. It was confirmed that the actuator of 10 mm in diameter fabricated with palladium has deformed by the introduction and evacuation of hydrogen gas. The height change and deformation rate have increased with the cycle between hydrogen introduction and evacuation.Copyright

A Study on the receding horizon guidance with the sequence optimization for the terminal area

The airspace near the airport, namely the terminal area, has serious congestion. To resolve the congestion, there are demands for the trajectory optimization and the sequence optimization of the arrival aircraft. In this paper, the algorithm to optimize the trajectory and the sequence simultaneously is shown. The receding horizon guidance (RHG) is employed for the trajectory optimization, and the trajectory is defined in the space-time coordinate system (STCS) to introduce the sequence optimization to the trajectory optimization. The simulation is performed to demonstrate the optimization process and the ability of the RHG. The simulation result shows that the RHG with the sequence optimization is able to optimize the trajectory and the sequence simultaneously.

Collision Avoidance Law Using Information Amount

The collision avoidance control has been one of the key technology for future transportation. Recently, many unmanned systems are developed in shapes of robots, cars, ships, aircraft, etc. In these environments, proper navigation and control systems including collision avoidance is needed. This paper is on collision avoidance control law for air vehicles under uncertain information. The control law uses information amount as one of the physical parameter for control system. In the field of guidance, navigation, and control, collision avoidance of automated transportation system has been one of main interest of researchers. Many researches started from collision avoidance of ships (Ciletti et al., 1997) where collision avoidance has been one of the problems due to the increasing demand for the naval transportations. Wide varieties of studies on collision avoidance are treated in fields of robots (Fukuda & Kubota, 1999), cars (Hiaoka et al., 2009a, 2009b) and satellites. Some of these researches treat avoidance problems with the formation control which requires the cooperative information control (Slater et al., 2006; Stipanovic et al., 2007). In the field of aeronautics, the Traffic alert and Collision Avoidance System (TCAS) has been one of the references for the collision avoidance. TCAS exchanges the information of aircrafts and advises the aircraft to avoid in vertical direction. For the conflicts in collision avoidance control, Frazzoli et al. (2001) have shown feasible strategy to treat the conflict problem. Gates (2009) has proposed rule-based collision avoidance control strategies for real-time online collision avoidance. Miele et al. (2010) has proposed collision avoidance control for case of abort landing with low computational load which can be calculated by on-board computer. Conventional avoidance problems assume that all information about avoidance (intruders and environments) is certain. Therefore, control law is designed based on certain information. However in real cases, all information may not be correct and most of it is uncertain. These uncertainty of information differes by the relative position of the evader and intruder or the absolute position of intruder. There has been no research on control law to deal with uncertain information. This paper proposes control law that treats uncertain information. New parameters quantifying information amount are defined for this purpose. The proposed control law provides new performance by enabling the aircraft to obtain information and to check the certainty of the information. Two different cases of numerical simulations are used to investigate the usage of the information amount. The first case defines the problem as the uncertainty of the information changes by the relative position of the evader and the target. The problem treats the case

Formation Control of Underactuated Satellite using Holonomy

Formation of satellites is difficult to control because of their unique system called the non-holonomic systems. One of the ways to control the non-holonomic system is to use the holonomy that appears when the periodic input is given to the non-holonomic systems. In this study, the formation of underactuated satellite is controlled using the holonomy. The satellite used in this study is simplified 2-dimensional model with only thrusters to change positions and to change its attitude angle. Various pattern of periodic input gives the different holonomy to the system. By combining the patterns of the holonomy, the satellite is able to move around to designated places and attitude. These combinations of the holonomy can be applied to the system to correct the attitude or position errors. This study also enables the satellite to move the satellite in rest-to-rest motion in the formation flight of multiple satellites

Robust polynomial guidance law for power descending phase of lunar lander

This paper is on polynomial guidance law for future lunar lander in power descending phase. To achieve pin-point landing, the guidance trajectory needs to be accurate. Boundary conditions are required to solve the polynomial guidance law, but the guidance law is designed in bases where the boundary conditions are nominal. This paper proposes the method to obtain boundary conditions from approximation when initial error occurs and give optimal trajectory even with the initial error. This paper shows the series of different initial errors and discusses the effect of the approximate error to the trajectory and fuel consumption. The results give some ideas for future navigation technology for lunar landing, which has error at the start of their power descending phase.