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HOME > No.29, May 2022 > A robot assisting elderlies in standing up, walking, and sitting down

A robot assisting elderlies in standing up, walking, and sitting down

Recognizing the state of users through few sensorsMizuki Takeda
Mizuki Takeda

A research team led by Mizuki Takeda, an assistant professor at the Department of Mechanical Engineering in Toyohashi University of Technology has developed a robot that can assist people in standing up, walking, and sitting down by estimating the user's state using a small number of sensors. They have developed a technique for a robot to estimate a user's state with few sensors by calculating center of gravity candidates. Knowing the state of the user, such as whether they are trying to stand up or sit down, makes it possible to provide assistance as necessary. Moreover, it can prevent accidents by detecting irregularities, such as the user almost falling over.

Assisting standing up. When the robot user leans forward, the robot detects it and assists in standing up by elevating the armrests.
Assisting standing up. When the robot user leans forward, the robot detects it and assists in standing up by elevating the armrests.

Elderly people, whose muscle strength weakens with age, may need to receive assistance in their daily lives, so robots are being developed to assist with especially frequent actions such as standing up and walking. Conventional robots have normally assisted in one of these actions, but since standing up, walking, and sitting down are done in sequence, it is desirable to have a single robot assist with them all.

Moreover, large-scale systems are often constructed to produce great force or recognize the user's state in detail, but systems for household use should ideally be small and have few sensors. If all movements are initiated by the robot, it may lead to dissatisfaction on two counts: muscular weakening and a reduced sense of independence on the part of the users. As such, they have developed a robot that allows the user to initiate movement and assists as appropriate by recognizing the user's situation and adding the force that is missing.

Assistance for standing up, walking, and sitting down. By estimating the user's state, a single robot can assist different movements like standing up, walking, and sitting down as a seamless sequence.

The research team focused on center of gravity as a key to estimating the robot user's state. Center of gravity is effective as an indicator of a person's state, cannot be accurately assessed with only a few sensors, so they developed a technique for calculating the range where center of gravity candidates can be found by considering data such as the motion range of joints. They produced a robot that uses these center of gravity candidates to estimate the user's state and detect irregularities through a type of machine learning called support vector machine and then move according to that information.

The research team believe that estimation of people's states using center of gravity candidates can be applied to welfare robots of various shapes and uses. Moreover, they want to make robots easier to use for elderly users by better understanding what movements the robots are expected to perform and how they should communicate with the users.


Mizuki Takeda, Kaiji Sato, Yasuhisa Hirata, Takahiro Katayama, Yasuhide Mizuta, and Atsushi Koujina (2021). Standing, Walking, and Sitting Support Robot Based on User State Estimation Using a Small Number of Sensors. IEEE Access.
doi: 10.1109/ACCESS.2021.3127275



武田 洸晶

豊橋技術科学大学機械工学系 武田 洸晶助教らの研究チームは、少数のセンサを用いて使用者の状態を推定して動作する起立・歩行・着座支援ロボットを開発しました。重心位置の候補点を計算することで、少ないセンサでロボット使用者の状態を推定する手法を開発しました。使用者が立とうとしている、座ろうとしているなどの状態が分かることで、それに応じて必要な支援を行うことを可能とします。また、転倒しそうな状態などの異常を検知することで、事故を防ぐ機能も実現しました。




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Researcher Profile

Mizuki Takeda
Name Mizuki Takeda
Affiliation Department of Mechanical Engineering
Title Assistant Professor
Fields of Research Robotics / Human-Robot Interaction / Care Robot / Robot Ethics