Find new and more efficient techniques in the treatment of cancer diseases is one of the main challenges in which the modern medicine is involved. Radiation therapy represents, in this field, an excellent alternative for inoperable patients, or when the surgery is rejected. Among all the used radiation therapies, proton therapy ensures well known dosimetric advantages in patients, and minimizes possible risks to damage vital organs causing unwanted side effects. Here is presented the "Enhanced Radiotherapy with HAdrons (ERHA)" project intended to design an innovative, compact and cheaper system for proton therapy delivery treatments. As part of this bigger system, a new prototype of "Robotised Patient Positioning System (RPPS)" is studied to provide an alternative solution compared with those commonly used.