This paper presents the mechatronic design of the Gyrolift chair, a new type of wheelchair associated with a personal transporter and equipped with a verticalization system. The verticalization system is designed to help users to reach a standing posture. This module allows disabled people to move from the seated position to the standing position. Thanks to this system people can stand safely and interact with objects in the environment that cannot be reached from the seated postion. The major contribution of this research is the design of a mechatronic system, defined by the morphology of the user, to enable suitable verticalization. A biomechanical model is also detailed to define morphological trajectories for the embedded verticalisation system. Experiments were carried out to evaluate and validate the system.