Professional Interactions with Professor Erskine Crossley

Abstract The authors describe several ways in which Professor Crossley's contributions have influenced their own professional lives and research. These range from Professor Crossley's work on constraint analysis, through his contributions as journal editor, and as a founder and officer of IFToMM, to his work in collaboration with Hunt on mechanical impacts. The latter body of work, in particular, has been important to our own work on modeling robotic foot-ground impacts.