This paper presents an analytical and experimental investigation of engagem
ent of parts aided by two orthogonal constant-amplitude sinusoidal motions
in mechanical assembly. In the analytical investigation we analyze how, the
amplitudes, frequencies, frequency ratio, and phase angle of the two motio
ns affect the engagement. A numerical technique is developed for selecting
these parameters, and a parts engagement strategy capable of recognizing va
rious failure situations in peg-in-hole assembly is developed. Experiments
are conducted to verify the validity of the parts engagement strategy as we
ll as to provide useful information about the characteristics of contact fo
rce during the engagement.