Research topics

Dynamics and control for airplane and spacecraft

Study on evaluation of social acceptability for the "Aerial Industrial Revolution"

Researches regarding flying vehicles have been actively conducted in many organizations in recent to develop a new flightable mobile infrastructure. New revolution, called “Aerial Industrial Revolution”, would occur in the near future. However, its social acceptability is not considered well even though the flying vehicles have a potential dangerous. In this work, we aim to develop a new methodology to evaluate the social acceptability. Currently, we are investigating the acceptability by humans using a brain wave measurement instrumentation and questionnaire -based psychological evaluation.

Image of flying vehicles
  • Susumu Hara, Yusuke Hayashi, Yasue Mitsukura, and Hiroko Kamide, Applicability of Kansei Analyzer for Noise-Induced Stress Assessment - Toward Social Acceptability Survey of Flying Cars-, Technical Journal of Advanced Mobility, Vol. 2, No. 3, pp. 31-41 (2021)

Seamless Switching Between Manual and Autonomous Navigation and Power Assist Control for Autonomous Mobile Robots

Recently, autonomous mobile robots are introduced in many factories; however, it is difficult to introduce them into aircraft manufacturing bases because of their complex situations. In the aircraft manufacturing bases, fully autonomous carrying by the robots is not required, instead, seamless switching between manual and autonomous navigation is required because workers sometimes want to control the robots manually. To achieve the requirement, the seamless navigation switching method and the power assist control in the manual operation for the robots are necessary. In this work, we aim to develop these methods.

Research Overview
  • Nguyen Gia Minh Thao, Shoya Hirokawa, Susumu Hara, Hiroyuki Okuda, Mitsuru Nagatsuka, Naoki Ogawa, and Tatsuya Suzuki, Introduction of a Manual Control Mode for Autonomous Mobile Robots to Transportation of Equipment in Manufacturing Sites of Aircraft Industry, Proceedings of the 2021 IEEE International Conference on Advanced Robotics and Its Social Impacts (ARSO 2021), pp. 127-130 (2021)

Moon and planetary landing dynamics and control

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
Simulation movie
  • 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)

Mid-Air Retrieval of Low-Speed-Descent Objects by Fixed-Wing UAVs

Deceleration by parachute is one of the most popular ways for safety measures of low-speed-descent objects such as radiosonde balloons and failure drones. However, it is difficult to control their landing points. Moreover, they might not decelerate enough to protect people or objects on the ground. This fact might cause serious accidents.
In this research, we propose the concept of mid-air-retrieval of low-speed-descent objects using fixed-wing unmanned aerial vehicles (UAVs). Especially, we focus on a control method to achieve the concept.

Research Overview
  • Shota Takeuchi, Shun Nakamura, Susumu Hara, and Kikuko Miyata, Updating Final-State Control Methods Taking Input Constraints at Final Time Into Account (Adaptive Flight Trajectory Design of Fixed-Wing UAVs), Journal of Advanced Mechanical Design, Systems, and Manufacturing, Vol. 14, No. 7, JAMDSM0106 (2020)

Research on Multicopter Landing Mechanisms

Recently, the logistics industry faces a shortage of labor, such as the aging of truck drivers. Moreover, the increase in online shopping causes traffic congestions. To overcome these situations, air transportation by multicopters and drones is expected to solve these problems. Some demonstration experiments have been already performed to achieve practical use. In previous experiments, multicopters were landed on a flat drone port which could estimate wind speed and direction and intrusion detection. However, the drone port is not always installed at the delivery destination. Therefore, they have to be landed on any surface without depending on the nature of the landing surface. In such a case, the most important problem is preventing falling.
In this study, we consider a mechanism to reduce rebound, which is one of the causes of falls. We propose a lightweight landing mechanism, which can be mounted on multicopters and drones that uses a magnetic damper. Magnetic dampers have many advantages such as mechanical simplicity that achieve straightforward design or low-temperature dependence, which enable usage under.

Proposed mechanism and process
  • Kazuki Niwa, Susumu Hara, and Kikuko Miyata, Development of Landing Rebound Reduction Mechanism Utilizing Magnetic Damper for Multicopters, Journal of Robotics and Mechatronics, Vol. 33, No. 2, pp. 223-230 (2021)

Study on stabilization control of motorcycles

Motorcycles are unstable vehicles compared to othermotor vehicles which have more than four wheels. They have huge risks of fall during low-speed driving or standstill. Therefore, the improvement in the safety of motorcycles is strongly required in higher the safety of the whole traffic society.
Our group studies on standing and stabilization control of motorcycles. The main control target is the mechanism called 'MOTOROiD'. The mechanism is invented by Yamaha Motor Co., Ltd., and we have been producing cooperative research since 2018. Our groupis in charge of the development of the control method, and construction of the mathematical models of MOTOROiD for the numerical experiment. We are designing the control method which achieves standing up from the parking mode, and the robust control methods for the various disturbances, such as wind.

MOTOROiD((c) Yamaha Motor Co., Ltd.)
  • Susumu Hara, Mitsuo Tsuchiya, and Tetsuya Kimura, Robust Control of Automatic Low-Speed Driving Motorcycle "MOTOROiD", Proceedings of the 2021 IEEE 10th Global Conference on Consumer Electronics (GCCE 2021), pp. 724-725 (2021)

Visual Based Tracking System in Asteroid Flyby

The flyby has attracted attention as a method of asteroid exploration. Spacecraft acquires various information while passing near the target asteroid. The camera imaging with target tracking is one of the most popular missions for the flyby.
However, there are two major issues in realizing tracking imaging. First, there are uncertainties in the parameters required for trackings, such as asteroid or spacecraft trajectories, asteroid diameter, and image sampling or quantization errors. These errors cause negative effects on tracking. Second, it is difficult to track and take the image of the target asteroid around the closest approach point between spacecraft and asteroid. The target angular rate rapidly increases around the closest approach point with the conventional tracking method, and it cannot be realized by the typical tracking system. In this research, we construct a control system that can solve these problems.

Overview of target pointing during flyby
  • Kikuko Miyata, Susumu Hara, Kenji Hayashi, Kenta Seki, and Makoto Iwasaki, Comparisons of Vision-Based Target Tracking Methods for Asteroid Flyby Problem, Proceedings of the 8th IEEJ International Workshop on Sensing, Actuation, Motion Control, and Optimization (SAMCON 2022), pp. 107-112 (2022)

Space-use Actuator System

Shape memory alloy (SMA) is the material which has a unique characteristic. The material can convert thermal energy directly into mechanical work. With proper thermal treatment, an SMA can remember its original shape and return to its pre-deformed shape when heated, even if it reaches plastic deformation when the deformation ratio is less than its recoverability, which generates a recovering force. Recently, SMA actuators get attraction because of their low shock, high safety, reusability, and ease of handling. One typical application of these kinds of actuators for spacecraft is the holding and release mechanism. The holding and release mechanism is a mechanism that holds an object safely even against external forces, such as vibration and shock, and instantaneously generates a force to release the object at the desired time and the system used pyrotechnic devices, conventionally. Our research group is challenging to improve the performance of these kinds actuators by constructing the mathematical model of the actuator and suitable control system.

System overview and force generation mechanism
  • Manato Nozaki, Kikuko Miyata, Susumu Hara, and Masatsugu Otsuki, A Robust Control System Against Temperature Variance for Space-Use SMA Actuators, to appear in Journal of Spacecraft and Rockets, Vol. 59 (2022)

Autonomous Navigation of UAVs

We have studied and developed autonomous driving technologies and try to apply these technologies for autonomous UAV navigation now. These technologies include environment mapping (SLAM), pose estimation on a map (localization), obstacle detection and recognition, and path planning and following control. In particular, we are focusing on how we can apply machine learning techniques for their autonomous navigation to realize more intelligent flight. We are also studying technologies for ground mobile robots.

  • Naoki Akai, Mobile robot localization considering uncertainty of depth regression from camera images, IEEE Robotics and Automation Letters, Vol. 7, No. 2, pp. 1431-1438 (2022)
  • Naoki Akai, Koki Yasui, Kazuya Arashi, Kane Saliou, Daisuke Tsubakino, and Susumu Hara, Bayesian filtering fusion of optimization-based monocular visual localization and autonomous quadcopter navigation, In Proceedings of the IEEE/SICE International Symposium on System Integration (SII), pp. 754-759 (2022)

Previous topics

Aircraft control

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.

Reserch overview
  • 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.

Reserch overview
  • 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.

The principle of billiards
Simulation model
  • 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)

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 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.

Mission Overview
Impact Geometry Map(IGM)
  • 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)

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.

Experimental System
Simulation Study Conditions
  • 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)