Many robot applications require legged robots to traverse rough or unm
odeled terrain. This paper explores strategies that would enable legge
d robots to respond to two common types of surface contact error: slip
ping and tripping. Because of the rapid response required and the diff
iculty of sensing uneven terrain, we propose a set of reflexes that wo
uld permit the robot to react without modeling or analyzing the error
condition in detail. These reflexive responses allow robust recovery f
rom a variety of contact errors. We present simulation trials for sing
le-slip tasks with varying coefficients of friction and single-trip ta
sks with varying obstacle heights.