The new architecture of ModGrasp for mind-controlled low-cost sensorised modular hands

ModGrasp, an open-source virtual and physical rapid-prototyping framework that allows for the design, simulation and control of low-cost sensorised modular hands, was previously introduced by our research group. ModGrasp combines the rapid-prototyping approach with the modular concept, making it possible to model different manipulator configurations. Virtual and physical prototypes can be linked in a real-time one-to-one correspondence. In this work, the ModGrasp communication pattern is improved, becoming more modular, reliable and robust. In the previous version of the framework, each finger of the prototype was controlled by a separate controller board. In this work, each module, or finger link, is independent, being controlled by a self-reliant slave controller board. In addition, a newly redesigned multi-threading and multi-level software architecture with a hierarchical logical organisation is presented. In this regard, a new programming paradigm is delineated. The new architecture opens up to a variety of possible applications. As a case study, a mind-controlled, low-cost modular manipulator is presented. In detail, the user´s levels of attention and meditation are monitored by using an electroencephalography (EEG) headset, the NeuroSky MindWave. These levels are used as inputs to control the hand. Since the manipulator features 11 DOFs, a synergistic control approach is chosen to map inputs with outputs with such a different dimensionality. Related simulations and experimental results are carried out.