Yukitoshi Minami | Waseda University (original) (raw)

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Papers by Yukitoshi Minami

2018 IEEE-RAS 18th International Conference on Humanoid Robots (Humanoids), 2018

Motivated by experiments showing that humans regulate their walking speed in order to improve loc... more Motivated by experiments showing that humans regulate their walking speed in order to improve localization performance, in this paper we explore the effects of walking gait on biped humanoid localization. We focus on step length as a proxy for speed and because of its ready applicability to current footstep planners, and we compare the performance of three different sparse visual odometry (VO) algorithms as a function of step length: a direct, a semi-direct and an indirect algorithm. The direct algorithm's performance decreased the longer the step lengths, which along with the analysis of inertial and force/torque data, point to a decrease in performance due to an increase of mechanical vibrations. The indirect algorithm's performance decreased in an opposite way, i.e., showing more errors with shorter step lengths, which we show to be due to the effects of drift over time. The semi-direct algorithm showed a performance in-between the previous two. These observations show that footstep planning could be used to improve the performance of VO algorithms in the future.

2017 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2017

The number of older adults is increasing much faster than the other age groups in the world. Espe... more The number of older adults is increasing much faster than the other age groups in the world. Especially in Japan, more and more older adult are becoming functionally independent. The smart home are appearing which provides comfort and monitors the life of the residents. However, when thinking about healthy older adults, there are two important points to take into account for the smart home: providing comfort and monitoring the position inside the house of the older adults on their daily life. This can also help their families giving them peace of mind. In this study, we designed a smart home system which includes low-cost sensor parts and a finger robot. This system can be used to control home appliances, such as air conditioners to keep the residents in a comfortable environment. Without the need of additional sensors only by using CO2 sensors, this system can provide information such as the room the resident is in, or if he/she is at home or not. As a result, we show a working system and the CO2 sensor is able to judge the position of the resident, and we are even able to understand the movement path of the resident.

2019 IEEE International Conference on Mechatronics and Automation (ICMA), 2019

In this paper, we developed a hybrid locomotion robot for earthquake search and rescue in partial... more In this paper, we developed a hybrid locomotion robot for earthquake search and rescue in partially collapsed buildings. The objective of this research is to find a new method to avoid rescuers from accessing partially collapsed buildings, and instead access these buildings using a robot, searching for trapped victims and transporting necessary goods (food, water, communication system and so on) to them. To achieve this goal, we design a robot with several functions which include: (1) hybrid locomotion (flying and moving on flat surfaces), (2) goods transportation mechanism, (3) victim detection sensing system, (4) victims position estimation system. In this paper, the details of the robot and some experimental results are presented.

2016 IEEE-RAS 16th International Conference on Humanoid Robots (Humanoids), 2016

In this paper we tackle the problem of visually predicting surface friction for environments with... more In this paper we tackle the problem of visually predicting surface friction for environments with diverse surfaces, and integrating this knowledge into biped robot locomotion planning. The problem is essential for autonomous robot locomotion since diverse surfaces with varying friction abound in the real world, from wood to ceramic tiles, grass or ice, which may cause difficulties or huge energy costs for robot locomotion if not considered. We propose to estimate friction and its uncertainty from visual estimation of material classes using convolutional neural networks, together with probability distribution functions of friction associated with each material. We then robustly integrate the friction predictions into a hierarchical (footstep and full-body) planning method using chance constraints, and optimize the same trajectory costs at both levels of the planning method for consistency. Our solution achieves fully autonomous perception and locomotion on slippery terrain, which considers not only friction and its uncertainty, but also collision, stability and trajectory cost. We show promising friction prediction results in real pictures of outdoor scenarios, and planning experiments on a real robot facing surfaces with different friction.

International Journal of Humanoid Robotics, 2016

We propose a novel heel-contact toe-off walking pattern generator for a biped humanoid robot. It ... more We propose a novel heel-contact toe-off walking pattern generator for a biped humanoid robot. It is divided in two stages: a simple model stage where a Linear Inverted Pendulum (LIP) based heel-contact toe-off walking model based on the so-called functional rockers of the foot (heel, ankle and forefoot rockers) is used to calculate step positions and timings, and the Center of Mass (CoM) trajectory taking step lengths as inputs, and a multibody dynamics model stage, where the final pattern to implement on the humanoid robot is obtained from the output of the first simple model stage. The final pattern comprises the Zero Moment Point (ZMP) reference, the joint angle references and the end effector references. The generated patterns were implemented on our robotic platform, WABIAN-2R to evaluate the generated walking patterns.

2013 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2013

We propose a two-stage gait pattern generation scheme for the full-scale humanoid robots, that co... more We propose a two-stage gait pattern generation scheme for the full-scale humanoid robots, that considers the dynamics of the system throughout the process. The fist stage is responsible for generating semi-dynamically consistent step position and step time information, while the second stage incorporated with multi-body dynamics system is responsible for generation of gait pattern that is feasible and stable on the full-scale multi-degree-of-freedom humanoid robot. The approach allows for very rapid gait pattern regeneration during the swing phase of motion and includes information about present dynamic state when regenerating the new pattern. The paper contains description of a developed method, as well as experimental results proving its effectiveness.

5th IEEE RAS/EMBS International Conference on Biomedical Robotics and Biomechatronics, 2014

We propose a new heel-contact toe-off walking model based on the Linear Inverted Pendulum (LIP) m... more We propose a new heel-contact toe-off walking model based on the Linear Inverted Pendulum (LIP) model, which due to the linearity and the ease of manipulation of the equations, could be considered to be advantageous for a future online implementation for the generation of walking patterns. This new model is based on the so called functional rockers of the foot (heel, ankle and forefoot rockers), each of which are modeled as an inverted pendulum, changing the ground contact point position of the inverted pendulums for each rocker. We focus on the motion of the Center of Mass (CoM) in the sagittal plane, as it is the plane on which the rockers take place, but also generate the motions on the frontal plane. The model proved to work for constant velocity, accelerating and decelerating gaits, and the effects of the change of pivot point during heel-contact toe-off could be corroborated in the Zero Moment Point (ZMP) graphs. The implementation of this model could improve the human likeness of the motions, as well as the stability of the locomotion.

2019 IEEE/SICE International Symposium on System Integration (SII)

Motivated by experiments showing that humans' localization performance changes with walking param... more Motivated by experiments showing that humans' localization performance changes with walking parameters, in this paper we explore the effects of walking gait on biped humanoid localization. We focus on walking style (normal and gallop) and gait symmetry (one side slower), and we assess the performance of visual odometry (VO) and kinematic odometry algorithms for the robot's localization. Changing the walking style from normal to gallop slightly improved the performance of the visual localization, which was related to a reduction in torques on the feet. Changing the gait temporal symmetry worsened the performance of the visual algorithms, which according to an analysis of inertial data, is related to an increase of mechanical vibrations and camera rotations. Both changes of gait style and symmetry decreased the performance of the kinematic localization, caused by the increase of vertical ground reaction forces, to which kinematic odometry is very sensitive. These observations support our claim that gait and footstep planning could be used to improve the performance of localization algorithms in the future.