Redundant actuation can help robots overcome singular configurations， while there is no consensus on whether it can improve the motion/force transmission performance of the mechanism. In this regard， firstly， a redundant actuated 4-revolute-joint，prismatic-joint，revolute-joint（4-PRR） planar parallel robot is designed， and its forward kinematics equation is established and analytically solved. Secondly， based on the scale constraint relationship， the rod length coordination equation is derived and analytically solved. Then， based on the displacement derivative method， the Jacobian matrix is derived and the singular configuration is analyzed. Thirdly， the local conditioning index （LCI） of the robot is solved by using mathematical tools such as the generalized inverse and the block matrix. Finally， the positive solution characteristics， singular configurations， and motion/force transmission performance of the 4-RPR parallel robot are compared with four types of 3-RPR parallel robots. Results show that the number of solutions to the forward kinematics equations of the newly designed robot is reduced by half， with fewer singular configurations and the proportion of high-quality workspace increased by 1.15% to 16.67%. This indicates that the 4-RPR planar parallel robot is easier to control in motion and has superior singularity performance， making it suitable for applications， such as 3D printing and palletizing， that require high flexibility.