Genetic algorithm-based optimal bipedal walking gait synthesis considering tradeoff between stability margin and speed

Goswami Dipa1, Vadakkepat Prahlada1 c1 and Phung Duc Kiena1

a1 Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576.


The inverse kinematics of a 12 degrees-of-freedom (DOFs) biped robot is formulated in terms of certain parameters. The biped walking gaits are developed using the parameters. The walking gaits are optimized using genetic algorithm (GA). The optimization is carried out considering relative importance of stability margin and walking speed. The stability margin depends on the position of zero-moment-point (ZMP) while walking speed varies with step-size. The ZMP is computed by an approximation-based method which does not require system dynamics. The optimal walking gaits are experimentally realized on a biped robot.

(Received May 05 2008)

(Online publication June 18 2008)


  • Biped robot;
  • Inverse kinematics;
  • Zero-moment-point;
  • Stability margin;
  • Walking speed;
  • Genetic algorithm


c1 Corresponding author. E-mail: