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Biped humanoid robot group WABIAN-2R (2006-) (WAseda BIpedal humANoid No.2 Refined) |
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| * Purpose |
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We have two purposes to develop a biped humanoid robot. The first one is to develop a robot that would be a human's partner, while the second one is to develop a human motion simulator. 1. Biped humanoid robot as a partner |
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 Cooperation with humans in various fields |
The robot industry thus far focused on developments of industrial robots, for highly specified and constrained applications.
The social demands and trends, however, push robotics into new areas, like medical treatment, life rescue, entertainment etc.
It is just a matter of time, when human beings will find robotic assistance necessary in their daily life. In order to accomplish these task, robots will have to be able to move in indoor and outdoor conditions. Biped humanoid robots are best suited for this application. |
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2. Biped humanoid robot as a human motion simulator
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| * Overview |
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* Specification |
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| Drawing | DOF configuration | |||||||||||||||||||||||||||||||||||||||
 Front |
 Right |
WABIAN-2R has been designed with 1.5m in height, and 64.5kg in weight. In order to mimic human movements, the robot has 41 DOFs and the movable range of the joints designed in reference to human's one. |
| WABIAN-2R (2008) | ||
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The computer mounted on the trunk controls the motion of WABIAN-2R. It consists of a PCI CPU board and PCI I/O boards.
As the I/O boards, HRP interface boards (16ch D/As, 16ch counters, 16ch PIOs), and 6-axis force/torque sensor receiver board are mounted. The operating system is QNX Neutrino ver. 6.3. The drive system consists of a DC servo motor with an incremental encoder attached to the motor shaft, and a photo sensor to detect the basing angle. Also, each ankle has a 6-axis force/torque sensor, which is used for measuring Ground Reaction Force (GRF) and Zero Moment Point (ZMP). |
| Control system |
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* 2-DOF waist mechanism (2003) |
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Because of the mechanical constraint, most of the biped robots perform a bent-knee gait (walk with the knees bent during walking). On the other hand, researches on human gait's analysis show that the pelvis motion plays a significant role in human's gait. Taking into account the results of these researches, our team developed a 2-DOF (roll, Yaw) waist. By using the redundant mechanism, the robot is able to perform a stretch-knee gait as well as human being does. | |
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* Foot with a passive toe joint (2006) |
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A human foot has a complex structure consisting of a lot of bones. Based on the result of gait analysis with motion capture system,
we have developed a new foot which has a passive toe joint. Some of the clinical reports on toes' function indicate that toes do not produce thrust during steady gait. Since, in the current stage of our research, we focus on in steady walking, we have decided to develop a foot with a passive toe joint. Its main advantages are lightness and no necessity of a complex control. |
| Foot with a passive toe joint | |
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* Walking stabilization control (-2008) |
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 Outline of the walking stabilization control |
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The gravity and inertia force must be balanced in a robot walking pattern (joint angle data on every moment). However, there are many errors that are not considered when the pattern is generated like unevenness, and inclination of the ground, an error between the real robot and the robot model (multi-mass system) and bend of the frame. So, a consideration of only gravity and inertia is not sufficient to achieve stable walking. To solve this problem, WABIAN-2R modifies the pattern based on the data of the GRF and attitude during walking. |
In order to do that, we use a vertual compliance control that makes the landing impact smaller. And also, Landing Pattern Modification Control（LPMC） changes the position and posture of the foot to adapt to the ground. Posture control corrects the error of robot's posture. WABIAN-2R can walk on a road with big slope or bump up to 5[deg] (roll and pitch) or 20[mm] (only pitch) with these control methods. In practice, we showed the high performance in experiments outdoor at Fukuoka city - stable walking on a slope in a park and on an uneven sidewalk. |
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* Foot mechanism adapting to the ground (2008) |
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In a real environment like outdoor road, bumps and slopes on the ground make walking unstable.
WABIAN-2R can continue walking with stabilization control described above to some extent.
However, it falls, when it fails adapting to the ground with big unevenness. We are trying to improve the walking ability not only with the control but also with a new foot mechanisms. One of the approaches is to detect ground before touching, while another is to adapt to the ground passively with a spherical joint mechanism. |
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| （a）Foot detecting ground | （b）Foot adapting passively | |
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* Power supply system (2007) |
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WABIAN-2R can use an external power supply and Li-ion batteries inbuilt in the body. On the other hand, we also use the external power supply when tuning-up the robot, and the inbuilt battery when performing experiments.
WABIAN-2R can switch smoothly between the external power supply and the batteries, to realize effective experiments as a human motion simulator. Furthermore, WABIAN-2R can charge the batteries when operating with the external power supply. |
| Effective power supply management | |
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| * Application as a human motion simulator |
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* Walking experiments with a walk-assist machine (2005) |
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As one of the applications as the human motion simulator, we carried out walking experiments with a walk-assist machine.
Generally, an armrest of a walk-assist machine is set to equal height of a user's elbow.
And it is known that the severer his/her disability is, the lower we should set it. Measuring the current value of the motors at the knee joints and the forces & torques which are applied to the arms and legs, we are able to calculate the energy consumption at knee joints and the load to arms. Then we found the fact with quantitative data that the lower we set the height of the armrest, the less the load of knees is. This is a good example that human motion simulator can evaluate empirical facts quantitatively. From the results of these experiments, we confirmed that we can evaluate welfare equipments quantitatively with a human motion simulator. |
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| WABIAN-2 with a walk-assist machine | ||
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* Emulation of a disabled person's gait (2007) |
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As an example of the robot's applications, we had emulation experiments of a disabled person's gait. We used the walking data of a disabled person, recorded with motion capture system. Optimazing a part of walking parameters with Genetic Algorithm (GA), the robot achieve a good balance between walking stably and reproducting the gait. As the result, we confirmed the effectiveness from the stick diagram in the sagittal plane and the comparison of each joint angle. |
| Emulation of a disabled person's gait | |
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* Experiments in public roads in Fukuoka city (2006〜2007) |
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For expansion of applied fields, we experimented in the environment where a human being lives.
In particular, in public roads in Fukuoka city that was the one of the special zones for robot development and test,
to confirm problems with the present walking ability, and to develop new control systems. This experiment was commissioned by the Robotics Industry Development Council (RIDC). |
| Experiments in public roads in Fukuoka city | |
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| * Experiments |
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* Reproduction of human walking (2002〜2006)
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| *Knee-bent walking |
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Conventional walking (mpg/13[sec]/2.3[MB]) Walking with constant waist height Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
| *Knee-stretch walking with waist movement |
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Stretch walking 1 (mpg/13[sec]/2.3[MB]) Walking with the knees stretched Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
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Stretch walking 2 (mpg/12[sec]/2.0[MB]) Walking with the knees stretched on tiled floor Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
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Stretch Walking 3 (mpg/12[sec]/2.1[MB]) Walking with the knees stretched outdoor Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
| *Human-like walking (Knee-stretched walking with heel-contact and toe-off motion) |
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Knee-stretched, heel-contact and toe-off motion 1 (mpg/13[sec]/2.2[MB]) In lab Walking cycle： 1.0[s/step] Step length： 350[mm/step] |
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Knee-stretched, heel-contact and toe-off motion 2 (mpg/11[sec]/1.9[MB]) In lab Walking cycle： 1.0[s/step] Step length： 500[mm/step] |
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Knee-stretched, heel-contact and toe-off motion 3 (mpg/13[sec]/2.2[MB]) Outdoors Walking cycle： 1.0[s/step] Step length： 350[mm/step] |
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Knee-stretched, heel-contact and toe-off motion 4 (mpg/11[sec]/1.9[MB]) Outdoors Walking cycle： 1.0[s/step] Step length： 400[mm/step] |
| *Detail of the heel-contact and toe-off motion |
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Detail 1 (mpg/8[sec]/1.3[MB]) Comparison of the foot motions between the robot and human |
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Detail 2 (mpg/12[sec]/2.1[MB]) Detail of the foot motion while walking |
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* Applications as a human motion simulator
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| *Walking experiments with a walk-assist machine (2005) |
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Simulations of walking assisted by a walk-assist machine (mpg/8[sec]/1.5[MB]) Knee-stretched walking with a walk-assist machine |
| *Emulation of a disabled person's gait (2007) |
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The emulation of a disabled person's gait (mpg/15[sec]/2.7[MB]) Emulation of a disabled person's gait |
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* Walking experiments on uneven road (2008)
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| *Walking experiment outdoor |
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Tiled uneven ground (mpg/13[sec]/2.2[MB]) Bump 5mm Slope 2deg Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
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Big slope (mpg/13[sec]/2.2[MB]) Slope 5deg Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
| *20mm bump in lab |
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Without detecting ground (mpg/13[sec]/2.2[MB]) Whole foot on 20mm bump Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
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With detecting ground (mpg/13[sec]/2.2[MB]) Toe & heel on 20mm bump Walking cycle： 1.0[s/step] Step length： 200[mm/step] |
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| * Collaborative research |
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"SHINPO" was developed in a collaboration of tmsuk Co., Ltd. and Atsuo Takanishi Laboratory for a part of the robot exhibition at Niigata Science Museum, which Uchida Yoko Co., Ltd. had contracted for. The 2-DOF waist enables it a more human-like walking style. Referential web page; Uchida Yoko Co., Ltd. http://www.uchida.co.jp/ Niigata Science Museum http://www.lalanet.gr.jp/nsm/index.html tmsuk Co., Ltd. http://www.tmsuk.co.jp/tmsuklab/ |
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| SHINPO | ||
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"KIYOMORI" was developed in a collaboration of tmsuk Co., Ltd. and the Atsuo Takanishi Laboratory. The same as "SHINPO", the 2-DOF waist enables it a more human-like walking style. Referential web page; "KIYOMORI" special web page http://kiyomori.jp/main.html |
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| KIYOMORI |
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| * Future work |
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We are trying to make the robot's ability higher to move close to humans and to have experiments with welfare equipments. In the future, we will establish the method to evaluate medical and welfare devices. Finally, we would also like to realize the human motion simulator, which can apply it to not only rehabilitation but also various fields. |
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| Future Work | |||
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| * Acknowledgements |
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A part of this research was commissioned by a Grant-in-Aid for the WABOT-HOUSE Project by Gifu Prefecture,
"Project for the Practical Application of Next-Generation Robots" by The New Energy and Industrial Technology Development Organization (NEDO),
The Robotics Industry Development Council (RIDC) and supported by Grant-in-Aid for Scientific Research (No.18360126)
from the Ministry of Education, Culture, Sports, Science and Technology. This project is executed under Humanoid Robotics Institute, Waseda University. Special thanks to SolidWorks Japan K.K for the 3D-CAD contribution, to QNX SOFTWERE SYSTEMS for the OS contribution, to DYDEN Corporation for the wire and harness contribution, and to every cooperative companies, local governments and public agencies. |
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| Takanishi Laboratory TOP | Last Update 2009.2.3 Copyright(C) 2008 Takanishi Laboratory All Rights Reserved. |