Posture control for humanoid robot on uneven ground and slopes using inertial sensors

Shu-Yin Chiang,Jin-Long Wang

doi:10.1177/1687814020957181

Abstract

We designed a stable gait pattern and posture-control balance system to enable a biped humanoid robot to maintain balance and avoid falling when walking on uneven ground or slopes. In this study, we first examined the problem of gait generation and the balance of a humanoid robot and then proposed a posture-control balance system using the inertial sensors of a gyroscope and accelerometer to sense the tilt angle of the robot according to the environment. To process the data obtained by the sensors, the mean filter was applied to eliminate the noise in the data, and the complementary filter was used to properly combine the data from both the gyroscope and accelerometer. The system further modifies the gait and posture of the robot based on the results obtained through a fuzzy system to attain the angle of balance and stabilization. A robot with an open platform was used to test the implementation of the proposed algorithm, and the experimental results demonstrated that the robot could successfully maintain balance when walking uphill and downhill on uneven surfaces. Moreover, because only one parameter needs to be adjusted when applying the balance-control system, the system can be easily extended to any related humanoid robot.

Highlights

With the rapid development of robots in recent years, the interaction between people and robots has become more common, and humanoid robots must be able to walk in various real-life environments, including hills and bumpy roads
We discussed the gait generation of the DARwIn-OP humanoid robot and proposed a balance control algorithm to enhance the stability of humanoid robot gait
We attempted to maintain balance for a robot to walk on uneven surfaces and slopes by using only built-in sensors, gyroscope, and accelerometer

Summary

Introduction

With the rapid development of robots in recent years, the interaction between people and robots has become more common, and humanoid robots must be able to walk in various real-life environments, including hills and bumpy roads. The corresponding procedure was conducted by substituting the parameters of the foot— Xtotal_r, Ytotal_r, Ztotal_r, atotal_r, btotal_r, and gtotal_r— into the calculation of inverse kinematics[36,37,38,39] to obtain the angles of the hip in a, b, and g directions, the knee in b direction, and the ankle in a and b directions.

Results

Conclusion