Forward and inverse kinematic analyses of a generic 6-R serial manipulator are carried out at both position and velocity levels. Singular configurations associated with the inverse position solution, designated as position related singular configurations (POSCs), and those associated with the inverse velocity solution, designated as velocity related singular configurations (VESOs), are investigated. At POSCs, the specified pose of the hand is not sufficient to determine some of the joint variables; the motion of the hand should also be specified. At VESCs, on the other hand, the joint variables can be determined, but to determine the joint velocities, the specified velocity state of the hand is not sufficient; its acceleration state should also be specified. Besides, the specified velocity and acceleration states should obey some compatibility conditions. Two methods are developed to determine the joint variables at POSCs and the joint velocities at VESCs. The first method, which is based on the L'Hopital's rule, is applicable only at the singular con figurations. The second method, which is based on analytical motion planning, is applicable not only at the singular configurations but also in the vicinity of them. (C) 1999 Elsevier Science Ltd. All rights reserved.