1. Adviser：Ming-Yuan Shieh Student：shun-te chuang SN：M9820204
Fuzzy Posture Control for Biped Walking Robot Based on Force Sensor for ZMP
Adviser：Ming-Yuan Shieh
Student：shun-te chuang
SN：M

2. Outline Abstract INTRODUCTION
SYSTEM CONFIGURATION AND KINEMATICS ANALYSIS
-System configuration
-Kinematics
ZMP MEASUREMENT BASED ON SENSOR
-Problem of analytic ZMP
-ZMP measurement based on force sensor
POSTURE CONTROL OF THE ROBOT
-Fuzzy posture algorithm
-Fuzzy rule for compensating coordinate of "Trunk“
EXPERIMENTS
CONCLUSIONS

3. Abstract
In this paper, ZMP trajectory following for biped walking robot based on force sensors and posture control using fuzzy algorithm are studied.
The posture control of the biped robot is performed by ZMP information in static standing. Posture of biped walking robot is controlled by fuzzy algorithm referring to the obtained ZMP trajectory information.
The result of this study is confirmed by experiment to apply fuzzy posture control against disturbance and to keep valance on a slope.

4. INTRODUCTION
A biped robot has a structure similar to human's leg and has higher mobility than conventional wheeled robots.
The biped walking robot is a multi-body system and has complex dynamics and many non-linear factors. Therefore it is very difficult to move a biped robot stably.
In this paper,ZMP is measured to judge stability of a biped robot by using force sensor attached to a sole of a foot. A posture control algorithm using fuzzy logic controls posture of the robot as using the obtained ZMP information.

5. System configuration
The developed biped walking robot is shown in Fig. 1.It's height and weight are 28cm and 3.2kg, respectively.
The biped robot is composed of 12 degrees of freedom.Fig. 2 shows coordinates of the developed biped robot.
The system can be divided into a control unit, a sensor module, and a motor module. The main control system is a Pentium X computer and has trajectory compensation algorithm of the biped walking robot and send command to control motor module of each joint.

6. Kinematics

7. Problem of analytic ZMP
The biped robot is supposed that robot is doing accurate action for analytic ZMP acquisition.
However control error of a biped walking robot exists clearly and a biped walking robot is not a perfect rigid body.
Specially, because each link of the biped walking robot is connected, the error due to connection affects stability of a biped robot. If we use actuator with the high torque and high accuracy or manufacture the robot using a rigid- body, this error can be reduce.

8. ZMP measurement based on force sensor

9. Fuzzy posture algorithm

10. Fuzzy rule for compensating coordinate of "Trunk“

11. EXPERIMENTS

12. EXPERIMENTS

13. CONCLUSIONS
The fuzzy posture control algorithm using ZMP information was introduced. The ground reaction force and the ZMP information was acquired as using force sensors.
And we could find position of center of gravity of the biped walking robot as using the acquired ZMP 1188 and could control in real time so that ZMP always exists within 'Desired area' by fuzzy posture algorithm.
Further works on the proposed 'fuzzy posture algorithm using ZMP information' improve posture stability by choosing the optimal fuzzy membership function and decrease time delay.