The　collision　avoidance　compliant　control　for　space　robot　on-orbit　capture　of　noncooperative　spacecraft　was　studied.　A　compliant　mechanism,　i.　e.,　Rotary　Series　Elastic　Actuator　(RSEA),　was　mounted　between　the　joint　motor　and　manipulator.　Its　functions　were　as　follows:　first,　the　deformation　of　its　internal　spring　could　absorb　the　impact　energy　of　the　captured　spacecraft　on　the　joints　of　the　space　robot;　second,　the　joint　impact　torque　could　be　limited　to　a　safe　range　by　combining　with　the　collision　avoidance　compliant　control　scheme.　The　dynamic　models　of　the　space　robot　and　target　spacecraft　before　capture　were　obtained　with　the　Lagrange　approach　and　Newton-Euler　method.　Then,　based　on　the　impulse　theorem,　kinematic　constraints,　and　the　law　of　force　transfer,　the　dynamic　model　of　the　composite　system　was　derived.　Finally,　a　passivity-based　neural　network　robust　H-infinity　compliant　control　was　proposed　for　the　post-capture　composite　system.　The　simulation　results　show　that　the　space　robot　system　with　RSEA　can　reduce　the　collision　impact　torque　of　the　joint　during　capture　phase　by　as　much　as　61.9%,　or　by　at　least　47.8%.　During　the　motion　stabilization　control　phase,　the　joint　impact　torque　is　limited　to　a　safe　range　to　realize　the　effective　protection　of　joints.　©　2020,　Science　Press.　All　right　reserved.