  In this paper, we study the regulation of the Ground Contact Forces (GRF) in
thruster-assisted legged locomotion. We will employ Reference Governors (RGs)
for enforcing GRF constraints in Harpy model which is a bipedal robot that is
being developed at Northeastern University. Optimization-based methods and
whole body control are widely used for enforcing the no-slip constraints in
legged locomotion which can be very computationally expensive. In contrast, RGs
can enforce these constraints by manipulating joint reference trajectories
using Lyapunov stability arguments which can be computed much faster. The
addition of the thrusters in our model allows to manipulate the gait parameters
and the GRF without sacrificing the locomotion stability.
