・Walking Up and Down Stairs, Carrying a Human
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　
・Calibration Method for Stewart Platform Leg　Mechanism　

・Landing Pattern Modification Method　

・WL-16RII Specification　

・Members　

1. Research Purpose
　 If a walk motion pattern on stairs is created by our pattern geneator already proposed, it is difficulut for the feet to reach the stairs because the stroke of its linear actuators is not enough. Our purpose in this research is the realization of walking up and down stably various stairs of human living enviroments, carrying a human.

2. Walking Control
　To deal with the problem, a yaw waist motion and preset ZMP trajectories are changed, and a walk motion pattern is generated.

3. Improvement on the hardware
　We improved the 3-DOF Passive joint to achieve the larege movavle range of rotation around Z axis.The Specification about WL-16RII is here.

(a) Going up and down stairs

Walking cycle：5.76 [s/step]
Step height：250 [mm] ,Pedal tread 500[mm]

(b) Going up and down stairs, carrying a human

Passenger's weight: 60[kg]
Walking cycle：5.76 [s/step]
Step height ：200 [mm] , Pedal tread: 500[mm]

(c) Going up and down stairs, carryng a human

Passenger's weight: 60[kg]
Walking cycle: 5.76 [s/step]
Step height: 150 [mm] , Pedal tread:300~500[mm]

(d) Going up stairs in the real environment,
carrying a human

Passenger's weight: 60[kg]
Walking cycle: 5.76 [s/step]
Step height:138.5~147.5 [mm]，Pedal tread:400 [mm]

(e) Going up outdoor stairs

Walking cycle: 5.76 [s/step]
Step height:128.9~143.2 [mm]
Pedal tread:250~300 [mm]

1.Research Purpose
Our purpose in this research is devising a new calibration method for Stewart Platform Leg　Mechanism to improve the reproducibility of experimental system.

2. Calibration Method
We developed two systems which enable us to understand the relation between the position and the orientaion of the waist and feet by watching.For position calibration, we used the position calibration system with two fiber sensors on the tip,and for orientation calibration, we used a digital angle meter.

※If these images are clicked, they will be enlarged.

3. Evaluation Experiment
Through walking experiments, we identified that the absolute position accuracy of feet was improved, and the reproducibility was improved.

1.Research Purpose
Our purpose in this research is the development of walking stbilization control method for unknown uneven surface in the real environment.

2.Walking Control
On our proposed method, nonlinear compliance control is applied to the foot motion, and comparing the theoritical and actual displacement, the shape of landing terrain is detected before landing impact force occurs, and from this, landing pattern of the foot is modified and the foot follows the terrain. Proposed method doesn't need any special sensors including gyroscopes, except the force sensors, and is also adoptable to concave or slope.

Block diagram of landing pattern modification method (Enlarged display)

(a) Walking experiment on uneven surface

Unevenness: 0~20[mm]
Landing pitch and roll angle:0~5 [deg]
Walking cycle:1.92 [sec/step]
Step Length: 200 [mm/step]

(b) Walking experiment in the real environment

Walking on Hakata Kotobuki-bashi bridge.
(It's public road!)
Walking cycle: 1.92 [sec/step]
Step Length: 200 [mm/step]

(c) Expriment Going up a stair with unknown rise

Preset height: 150[mm] , Actual height: 130[mm]
Walking cycle: 5.76 [s/step]
Pedal tread: 500 [mm]

(d) Experiment going up a stair with unknown rise

Preset height: 150[mm] , Actual height: 170[mm]
Walking cycle: 5.76 [s/step]
Pedal tread: 500 [mm]

Project Leader：Prof.Takanishi
Doctor course：Yusuke Sugahaha
Master course：Masamiki Kawase, Kenji Hashimoto, Akihiro Ohta, Chiaki Tanaka
Undeargraduate：Nobutuna Endou, Terumasa Sawato, Akihiro Hayashi