A new architecture is suggested in this paper for an Assistive Platform in an Ambient Computing for elderly or disabled people. In this situation, interaction between the user, the environment and the platform is guided by means of a generated process. Depending on the context, the elements of the process are dynamically assembled. The aspect of assembly is based on rules that are set through an online learning operation. This new approach of designing an assistive platform is validated through devices integrated in a powered wheelchair with those implemented within the environment. Rules of operation evolve depending on a data base which is continuously updated depending on user’s daily activities.