Posture Control for a Low-Cost Commercially-Available Hexapod Robot

Posture control for legged robots has been widely developed on custom-designed robotic platforms, with little work being done on commercially-available robots despite their potential as low-cost research platforms. This paper presents the implementation of a Walking Posture Control system on a commercially-available hexapod robot which utilizes low-cost joint actuators without torque control capabilities. The hierarchical control system employs Virtual Model Control with simple foot force distribution and a novel, position-based Foot Force Controller that enables direct force control during the leg's stance phase and active compliance control during the swing phase. Ground truth measurements in experimental tests, obtained with a Vicon motion capture system, demonstrate the improvement to posture made by the control system on uneven terrain, with the results comparing favorably to those obtained in similar tests on more sophisticated, custom-designed platforms.