For the next generation lunar planetary exploration mission, the landing technique is very important to explore the surface of the celestial bodies. Since the scientifically important places are not suitable for landing due to the steep topography, more effective mechanisms for landing on the surface with severe condition is required. Therefore, the overturning-preventation is a major issue for the landers. To solve the problems, our research group focuses on the momentum exchange and energy conversion for shock absorbing and overturning-prevention at landing. Our group proposes the various landing mechanisms and control methods from the point of this view.
Overview of the experimantal model
Susumu Hara, Keisuke Sugita, Satoshi Saito, Takao Maeda and Masatsugu Otsuki, Free-Fall Landing Experiments and Simulations of Three-Dimensional Linear-Rotary-Energy-Conversion Mechanism, The 17th Space Science Symposium, P-176 (2016) (in Japanese)
Susumu Hara, Satoshi Saito, Keisuke Sugita and Takao Maeda, Planetary Exploration Spacecraft Landing Gear with Three-Dimensional Linear-Rotary-Energy-Conversion Mechanism, The 31st International Symposium on Space Technology and Science, 2017-k-36 (2017)
Takao Maeda, Takeshi Ozaki, Susumu Hara and Shintaro Matsui, Touchdown Dynamics of a Planetary Lander with a Translation-Rotation Motion Conversion Mechanism, Journal of Spacecraft and Rockets, Vol. 54, Issue 4, pp. 973-980 (2017)
Recentlly the popularities of the Unmanned Aerial Vehicles (UAVs) are increasing for various applications such as transportation. In particular, the combination of the "Hovering capability" like helicopter, and "High-speed flight ability" like a commercial plane is required. These abilities can realize the transportation between the isolated islands and more extensive and highly accurate environmental observation, for example. The Vertical takeoff and landing aircraft (VTOL) are attracting attention as the aircraft that realize the functions. Our research group focuses on the Tilt-Wing aircraft, one of the VTOL machines. This aircraft realizes hovering and high speed flight by changing the angle of the wing (tilt). The problem addressed for the aircraft is the difficulty of the flight trajectory stabilization. Since the aircraft changes the angle of the wing, the dynamic change of the characteristics of the motion should be considered during the flight. To solve this problem and realize the flight stabilization from a view point of control engineering, we introduce the new indices called "region of attraction". With this indices, we evaluate stabilization and simultaneously optimize control methods and body structure to reduce the control effort.
Jumpei Nakamura, Takamasa Horibe, Susumu Hara and Daisuke Tsubakino, Design Parameters Optimization of Quad Tilt-Wing Aircraft by Means of Quantitative Evaluation of Region of Attraction, The 53rd Kansai Branch-Chubu Branch Joint Autumn Meeting, D10 (2016) (in Japanese)
Susumu Hara, Hisashi Nagamatsu, Jumpei Nakamura, Takamasa Horibe and Daisuke Tsubakino, Flight Control of Quad Tilt Wing UAV and Its Stability Analysis by Region of Attraction, The 48th JSASS Annual Meeting, 1C08 (2016) (in Japanese)
Study on motion control of electric vehicles
It is widely known that the electric vehicles well have been used in our society. One of the important themes for electric vehicle is the battery management. Previously, we cannot use the full abilities of the electric vehicles because of the uncertanty of the battery states.
The state estimation method of batteries has been developed rapidly
and now we can estimate the state of charge (SOC) with high accuracy.
Our group aims to develop the effective motion control methods
taking the recent battery management technique into account,
especially in the UAV field. We aim to achieve the drastically extention of the cruising range only by improving the software of UAV.
Koya Kuwamura and Susumu Hara, Application of Battery Information to Effective Unmanned Aerial Vehicle Control,Tokai Engineering Complex 2017, 322 (2017)
Study on settling control of horizontal moving body
With the experience of the planetary landing mechanisms, our group treats settling control of horizontal moving bodys which is mainly realized by momentum exchange without using brakes.
This technique is expected to save time for the transportation. In our group, the technique is exploitted to the mechanism which reduces the rebound of the horizontal moving body colliding with a wall and realizes the settling control.
Susumu Hara, Naoko Mishima, and Koya Kuwamura, Proposal of Horizontal Moving Body Settling Control Mechanism Mainly Realized by Momentum Exchange -Hybrid Mechanism Consisting of Passive MEID Deceleration and Active MEID Rebound Suppression-, The 17th SICE System Integration Division Annual Conference, 1209-1212 (2016) (in Japanese)
Autonomous Spacecraft Operation with Efficient On-board Operation Planning System
Recent years, research and development of microsatellites have become active, because of their low development cost and short development period.
However, microsatellites have strict resource limitation from their launch mass and volume constraints. In addition, they tend to give priority to stable operation of the spacecraft and build the conservative operation plan with the excessive safety margin to the limited resources, which prevent enlarging the possibilities of the systems.
In this research, we are trying to implement the automation and autonomous functions that maximize the utilization of limited resources to enlarge the possibilities of microsatellites system. Especially, we focus on the construction of the power management system of the satellites to maximize the mission operation time with the combination of the accurate battery status estimation system and the efficient autonomous operation planning system.
Arata Takaki, Kikuko Miyata, Kohei Yamaguchi and Susumu Hara, Proposal of effective operation method specialized for microsatellites in Low Earth Orbit, The 18th Space Science Symposium, P-162 (2018) (in Japanese)
Arata Takaki, Kikuko Miyata, Kohei Yamaguchi and Susumu Hara, A study of power management based on battery state estimation for effective operation of microsatellites, The 49th JSASS Annual Meeting, 1D07 (2018) (in Japanese)
Study on a Trajectory Optimization of Spacecraft for Asteroid Deflection Exploiting Impact Geometry Map
Collisions of asteroids with Earth sometimes occur and cause severe damage to human society. To mitigate this disaster, asteroid deflection techniques which avoid the collision by changing asteroid’s path are discussed. Study on asteroid deflection techniques is uncommon in Japan, and still developing.
The Kinetic Impactor(KI) approach that sends a spacecraft to crash into an asteroid at hypervelocity in order to change its path is proposed as one of asteroid deflection techniques. Since there is an example that an impactor collided with a comet, this technique has high potential for practical use. Additionally, the KI method still has a possibility to improve focusing on impact effects.
Impact Geometry Map(IGM) that visualize the achievable change in the asteroid’s orbital energy caused by the KI was proposed to evaluate the impact effects.
In this research, we propose a trajectory optimization method for the improvement of the KI by exploiting IGM in order to enhance the impact effects.
Ryo Hayama, Kohei Yamaguchi and Susumu Hara, Study on Trajectory Optimization Method of Spacecraft as an Impactor for Asteroid Deflection Exploiting Impact Geometry Analysis, The 26th Space Engineering Conference, 1A2 (2017) (in Japanese)