Body levelling of a hexapod robot using the concept of sensor fusion

Abstract

Contrary to their wheeled counterpart, multi-legged robots are capable of easily changing their body posture through reconfiguration of the legs (i.e. inclination or posture control). This capability is exploited in the paper at hand to level out a six-legged robot when placed on a plain slope with adjustable inclination. By extension such inclination control could then be used to let the legged robot mount plain slopes with its body horizontally which greatly benefits the way the robot absorbs the load posed on its mechanics. The implemented body levelling algorithm uses the hexapod's forward and inverse kinematic model, basic geometry, and the Cartesian plane equation to calculate the leg tip displacements able of counteracting the fused orientation data obtained from an inertial measurement unit (IMU). Experimental results show the approach to be successful, although the speed of the levelling process leaves room for improvement. To address the latter a more powerful processing unit and/or, more importantly, a simpler redesign of the legs is advised.