Parametric Design of a Finger Rehabilitation Mechanism with Double Action and Two Degrees of Freedom

The objective of this work is to design a rehabilitation mechanism for the index finger that can replicate the finger's natural movements in the sagittal plane; this mechanism must also be able to adapt to an individual's anthropometric dimensions. The personalization of the mechanism is made through a parametric model assisted by computer-aided design software. An infrared motion capture system is used to validate the natural finger movements, comparing them to the ones generated by the parametric designed mechanism. The replication of natural finger movements with this mechanism is possible due to the use of virtual centers and the employment of two degrees of freedom. One degree of freedom is proximal phalanx flexion-extension, and the other one is the middle-distal phalanges conjoined movement. The replication of natural motions and the use of personalization techniques offer three main advantages: a diverse set of rehabilitation exercises, an increase in the range of motion of the finger compared to other designs in the literature and the short construction time required for the rehabilitation device.