This paper deals with the design of a robust control scheme for a suspended Cable-Driven Parallel Robot (CDPR), composed of eight cables and a moving platform (MP), dedicated to pick-and-place metal plates with different shapes, sizes and masses. The set composed of the MP and a metal plate can have a mass of up to 700 kg. In the proposed control solution, a decentralized control scheme is implemented on the robot. In order to achieve good accuracy and robust control, a recently developed controller balancing between sliding mode and linear (SML) algorithms is implemented on a CDPR prototype located at IRT Jules Verne, Nantes, France. The performances of the SML controller are analyzed along a test trajectory for several payloads. The results obtained without any information on the platform or metal plate mass are compared to those of standard proportional-derivative (PD) based control schemes.