Milankovitch cycles do affect climate on Earth. There are several cycles.
"Variations in eccentricity, axial tilt, and precession of the Earth's orbit resulted in cyclical variation in the solar radiation reaching the Earth, and that this orbital forcing strongly influenced climatic patterns on Earth." source: wikipedia
Scientifists of Pleistocene's climate evolution strongly correlate Milankovitch cycles with glaciar/interglaciar periods.
Other factors of Earth's internal system, such as volcanic events do affect climate, but changes in the magnitude of solar radiation are a well known climatic variability generator.