1. Balance control of humanoid robot for Hurosot
16th IFAC, Jul., 8, 2005
Balance control of humanoid robot for Hurosot
Bum-Joo Lee, Yong-Duk Kim and Jong-Hwan Kim
Robot Intelligence Technology Lab.
KAIST
Robot Intelligence Technology Lab.

2. Contents Introduction Gait generation Balance control Experiment
First phase: walking pattern generation
Second phase: yawing moment cancellation
Balance control
Inverted pendulum model
Compensation method
Experiment
Conclusions
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3. 1. Introduction Humanoid robot HanSaRam Stability
Biped (two-legged) robot.
Expected to eventually evolve into one with a human-like body and intelligence.
HanSaRam
Meaning ‘one human being’ in Korean
A humanoid robot undergoing continual design and development in the Robot Intelligence Technology Laboratory at KAIST since 2000
Stability
ZMP (Zero Moment Point) must always reside in the convex hull of all contact points on the ground plane.
ZMP: the point on the ground plane at which the total moments due to ground contacts becomes zero, proposed by Vukobratovic
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4. 1. Introduction HSR-I, II: 2000
HSR-IV
HSR-V
HSR-VI
HSR-I, II: 2000
- Easy to make and control, Lack of torque
HSR-III: 2001
- 12 DC motors and 10 RC servo motors
- Human-like body
- No sensor feedback
HSR-IV: 2002
- 12 RC servo motors
- Feedback using force sensors
- No upper body
HSR-V: 2003
- 12 DC motors and 16 RC servo motors
Feedback using force sensors
- Human-like body
HSR-VI: 2004
- 12 DC motors and 13 RC servo motors
Feedback using force sensors
- Improved performance
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5. 1. Introduction
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6. 2. Two Phase Off-line Gait Generation
Control architecture
Robot (HSR-V)
ZMP Compensator
Two Phase Off-line Gait Generator
< Off-Line >
< On-Line >
ZMP Calculator
Step Time,
Step Size,
Maximum Foot Height
Gait Generation
Using Simulator
1st Phase
Yawing Moment
Cancellation
Trajectory
Compensated Reference
Joint Angle
Real Joint Angle Feedback
Sensor Data
Measured ZMP Data
Reference
2nd Phase
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7. 2. Two Phase Off-line Gait Generation
First phase: walking pattern generation
Posture vector
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8. 2. Two Phase Off-line Gait Generation
Gait generation (Huang 2000)
1) Foot trajectory
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9. 2. Two Phase Off-line Gait Generation
2) Hip trajectory
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10. 2. Two Phase Off-line Gait Generation
3rd order spline interpolation
Interpolate at
Match velocity and acceleration values at every via points.
 Calculate the trajectories of ankle and hip joints.
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11. 2. Two Phase Off-line Gait Generation
Second phase: yawing moment compensation
ZMP equation:
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12. 2. Two Phase Off-line Gait Generation
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13. 2. Two Phase Off-line Gait Generation
Off-line yawing moment cancellation:
Above equation can be solved by numerical double integration.
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14. 3. On-line Balance control
Robot modeling for online compensation
Inverted Pendulum
Model
< Lumped upper body model >
< Simplified upper body model >
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15. 3. On-line Balance control
On-line compensation equation
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16. 3. On-line Balance control
Continued
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17. 3. On-line Balance control
Continued
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18. 4. Experiments Two phase off-line gait generation
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19. Online Balance Control
4. Experiments
Online Balance Control
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20. 4. Experiments
ZMP trajectory without compensation (pre-designed ZMPx = 15mm)
(a) ZMP trajectory (5 degree tilt)
(b) waist angle trajectory.
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21. (b) waist angle trajectory.
4. Experiments
ZMP trajectory with compensation ( at 5 degree tilt)
(a) ZMP trajectory.
(b) waist angle trajectory.
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22. Ongoing research: HuroSot
4. Experiments
Ongoing research: HuroSot
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23. 5. Conclusions
This paper has presented an overview of research development in humanoid robot HanSaRam.
The off-line gait generation method and the on-line compensation algorithm was proposed.
By putting arm-swinging motion in the off-line gait generation stage, the yawing moment could be cancelled.
ZMP compensation has been accomplished by moving the upper body front and rear in on-line walking.
Robot Intelligence Technology Lab.