Sensor Information Analysis for a Humanoid Robot

For a humanoid robot to safely walk in unknown environments, various sensors are used to identify the surface condition and recognize any obstacles. The humanoid robot is not fixed on the surface and the base/orientation of the kinematics change while it is walking. Therefore, if the foot contact changes from the estimated due to the unknown surface condition, the kinematics results are not correct. The robot may not be able to perform the motion commands based on the incorrect surface condition. Some robots have built-in range sensors but it's difficult to accurately model the surface from the sensor readings because the movement of the robot should be considered and the robot localization should have zero error for correct interpretation of the sensor readings. In this paper, three infrared range sensors are used in order to perceive the floor state. Covariance analysis is incorporated to consider the uncertainties. The accelerometer and gyro sensor are also used in order to detect the moment a foot hits the surface. This information provides correction to the motion planner and robot kinematics when the environment is not modeled correctly.