  Soft pneumatic legged robots show promise in their ability to traverse a
range of different types of terrain, including natural unstructured terrain met
in applications like precision agriculture. They can adapt their body
morphology to the intricacies of the terrain at hand, thus enabling robust and
resilient locomotion. In this paper we capitalize upon recent developments on
soft pneumatic legged robots to introduce a closed-loop trajectory tracking
control scheme for operation over flat ground. Closed-loop pneumatic actuation
feedback is achieved via a compact and portable pneumatic regulation board.
Experimental results reveal that our soft legged robot can precisely control
its body height and orientation while in quasi-static operation based on a
geometric model. The robot can track both straight line and curved trajectories
as well as variable-height trajectories. This work lays the basis to enable
autonomous navigation for soft legged robots.
