Research interests

Welcome to my personal website. Here you will find information about me. Graduate student (a 3nd year Doctors degree student) (CV2014: PDF)

◇ E-mail : urai.kenji[at]

Research GatecrewwLinkedIn

1) Research Interests 2) Publications 3) Education 4) Others

physical Human Robot Interaction (pHRI)

  • Humanoid robot (ref. 1-5, 2-3, 3-3, 3-5, 3-6, 3-7, 3-8, 3-11, 5-3, 6-4, 6-6) → HUMA Project : Web page and Video

Development of a Human-like Upper body Musculoskeletal robot driven by Air actuators (HUMA) : In this research, a human-like upper body musculoskeletal robot (HUMA) with redundant joints and actuators is developed. The robot can change its passive dynamics just by changing the connection of air actuators, i.e., changing the constraint of joints. HUMA can realize some open-loop motions by it.

A Study on Response Adjustable Mechanisms for Various Physical Interaction : Recently, robots are expected to support actions performed in a real-life environment in our daily lives. However, robots encounter several interferences while performing physical interactions, such as shaking hands, hugging, and holding various objects. Therefore, it is difficult for the robots to perform such actions flexibly owing to the unexpected noises associated with these actions. Humans, in contrast, can cope with various disturbances thanks to the property can change the passive dynamics depending on the situation and task. In our study, a human-like musculoskeletal robot (HUMA) comprising redundant joints and actuators is developed.

The robot can change its passive dynamics by simply changing the mutual interconnection of air actuators (Actuator Network System (ANS) : ANS can generate various responses of the whole robot body by switching the connections between cylinders using valves). We expect this idea allows the robot to cope with various disturbances.

  • Joint mechanism (ref. 1-4, 3-2, 4-1, 6-1) → Double joint mechanism : Video

Development of a large moving range shoulder joint for a humanoid robot : This joint mechanism is composed of two ball joints laying back to back and the range of motion is larger than that of a usual ball joint. Since the joint is driven by the mutually inter-connected air cylinders, the control signal can be operated equally with a normal ball joint shoulder. The prototype of the joint with 6 air cylinders and its kinematic model were developed to confirm its range of motion. We also achieved an overhand throwing motion with a robotic arm using the proposed shoulder mechanism thanks to the large moving range.

  • Control method with non-parametric regression models (ref. 1-1, 1-2, 2-1, 2-2) → Adaptive pyhisical interaction system with GPR : Video

Estimation of physical interaction between a musculoskeletal robot and its surroundings : Recently, robots are expected to support our daily lives in real environments. In such environments, however, there are a lot of obstacles and the motion of the robot is affected by them.

In this research, we develop a musculoskeletal robotic arm and a system identification method for coping with external forces while learning the dynamics of complicated situations, based on Gaussian process regression (GPR). The musculoskeletal robot has the ability to cope with external forces by utilizing a bio-inspired mechanism. GPR is an easy-to-implement method, but can handle complicated prediction tasks. The experimental results show that the behavior of the robot while interacting with its surroundings can be predicted by our method.

  • Bio-inspired robot (ref. 1-3, 2-4, 2-5, 3-1, 3-4, 3-13, 5-1, 6-2, 6-3, 6-5, 6-7, 6-10, 6-11, 6-12) → Stingray Project : Web page and Video

Development of a underwater soft robot based on morphological features of ray : Underwater tasks are diversified and articulated. The environment in which they must be accomplished is often unconstrained and unpredictable. Operating AUVs assuring safety of the robot and of its surroundings is therefore very difficult. On the other hand, many fishes are able to easily move in the same environments. A crucial factor for this capability is their body, which consists primarily of elastic and soft structures that enable both complex movement and adaptation to the environment. Among the most efficient swimmers we find rays, which show abilities like high speed turning and omnidirectional swimming. In our study, we propose an underwater soft robot based on the morphological features of rays. We mimic their skeletal structure and the compliance of their fins. This property provides an adaptive deformation that allows our robot to swim smoothly and safely.

Rays are very efficient swimmers. Their major swimming modes are “mobuliform” , which occurs as the pectoral fins flap up and down, and “rajiform”, defined as having one or more waves present on the fin at a time, which can create great maneuverability and various movements.

<Bonus material> Is the stingray-like robot walkable? : Can we use the developed stingray-like robot as a walking mechanism? We verified whether walking is possible by changing the skeleton arrangement of the robot. Locomotions was generated by handcrafted control signals (there is no relationship with the locomotion under the water). As a result of the experiment, it was confirmed that it was movable if walking with sliding feet. However, it was not practical and efficient walking was difficult.

  • life-like robot (ref.) → Artificial life project in preparation
  • Life care robot (ref. 7-3, 7-4) → Sign robotics project : Web pages and Video (関連記事:URL, URL

Development of a watching robot system using only highly anonymous information: Communication with families living far away is often forgotten. Mimamoroid provides "peace of mind" to families living separately. Mimamoroid is used in pairs. Families living separately own each one. By synchronizing the state of each robot (movement and LED light) in real time, it gives you a sense of security that you are "connected" or "nearby" to a distant family. Mimamoroid realizes new communication style with robots.

The watching robot that does not monitor it is "Mimamoroid". There is no camera in Mimamoroid. Mimamoroid has odor, noise, temperature sensor and so on. By analyzing sensor information with high anonymity, we will inform you of reliable "safety" information. We do not communicate much information. We will communicate only the information of "the safety of each other" that we would like to know the most.

Human Robot Interaction (HRI)

  • Group communication (ref. 3-9, 3-10, 3-12, 3-14, 5-2, 5-4)

Fluid mechanics

Study on mutual interference of flows caused by multiple objects: In urban high-rise buildings, a strong wind including a gust of wind called the building wind occurs. It destroys the wind environment on the ground and it becomes a social problem. This is due to mutual interference that occurs when a fluid moves through multiple objects. However, research results on mutual interference are few at present. In this research, mutual interference was investigated by performing flow visualization experiment and numerical analysis.


  1. HUMA vol.2 (2015-).
  2. HUMA vol.1 (2014-2015).
  3. Musculoskeletal robot (2013-2014).
  4. Stingray robot (2014-2015).