A　performance　index　of　local　dexterity　stiffness　index　(LDSI)　is　proposed　to　consider　both　kinematic　dexterity　and　static　rigidity　characteristics　of　a　parallel　kinematic　machine　(PKM).　Based　on　the　proposed　index,　the　static　performance　of　an　Exe-Variant　PKM　module　is　predicted　in　a　quick　manner.　Since　the　proposed　LDSI　is　a　dimensional　index,　a　dimensionless　global　index　is　further　presented　to　optimize　the　geometric　parameters　of　the　PKM　module.　An　optimal　searching　algorithm　is　used　to　obtain　reasonable　radii　of　the　moving　platform　and　the　fixed　base　of　Exe-Variant　PKM.　©　Springer　Nature　Singapore　Pte　Ltd.　2017.