Just to comment, there is something already in the Core\Def\ThingsDef\Races.xml that looks like a good start.
Code Select
<ThingDef ParentName="BasePawn">
<defName>Mechanoid</defName>
<label>Mechanoid</label>
<maxHealth>350</maxHealth>
<overdraw>true</overdraw>
<sunShadowInfo>
<baseWidth>0.6</baseWidth>
<baseWidth>0.6</baseWidth>
<tallness>0.8</tallness>
</sunShadowInfo>
<race>
<walkSpeed>0.25</walkSpeed>
<isFlesh>false</isFlesh>
<meleeDamage>20</meleeDamage>
<nameCategory>Robot</nameCategory>
<hasGenders>false</hasGenders>
<hasStory>true</hasStory>
<needsRest>false</needsRest>
</race>
</ThingDef>