A new 3-DOF planar parallel manipulator which consists of a moving platform connected to a fixed base by three different kinematic-chain limbs is presented.Another novel planar parallel manipulator is obtained by combining two revolute joints into one from the original manipultor.The output motion characteristic of the moving platform is analyzed based on the units of singleopen-chain theory.The kinematics equations of position and velocity are kinematics are derived.The Jacobian matrix is a 3×3identical one

so there is exists one-to-one mapping relationship between the output velocity vector of the platform and the input velocity vector of the actuated joints.One output motion of the platform only need one actuated joint control.Furthermore

conditioning number of Jacobian is constantly equal to one and the manipulator shows fully-isotropic throughout its entire workspace.