In　view　of　the　fact　that　robots　are　easy　to　collide　with　humans　or　obstacles　which　go　into　its　workspace,　a　collision　detection　algorithm　based　on　generalized　momentum　deviation　was　proposed　to　improve　the　safety　of　robots.　According　to　the　decoupling　performance　between　generalized　momentum　and　external　torque　of　manipulator,　a　momentum　deviation　observer　was　firstly　designed　to　obtain　the　impact　force.　Then,　a　performance　regulating　function　was　introduced　to　improve　its　dynamic　response　characteristics.　Once　impact　force　was　detected,　it　is　possible　to　judge　whether　the　collision　occurred.　With　this　algorithm,　collision　can　be　detected　in　real　time,　and　can　effectively　avoid　the　influence　of　acceleration　or　deceleration,　without　any　additional　external　sensors　or　acceleration　of　the　manipulator,　simply　by　measuring　the　motor　current　and　the　position　got　by　encoders　of　each　joint.　Simulation　and　experiment　results　show　that　the　algorithm　has　reached　the　expected　requirements　in　real-time　performance.　And　the　disturbances　caused　by　accelerating　and　decelerating　of　manipulator　are　also　very　small.　Moreover,　it　provides　an　approximate　position　and　direction　of　the　impact　force　which　has　important　significance　for　further　security　reaction　control.　©,　2015,　Editorial　Department　of　Electric　Machines　and　Control.　All　right　reserved.