Evaluation of sensory substitution to simplify the mechanical design of a haptic wrist

The design of a new 3 degrees-of-freedom (DOF) haptic wrist for our 3-DOF force feedback haptic device is presenting a great design challenge. Demanding target specifications make it difficult to find a satisfactory mechanical design solution. This paper studies whether sensory substitution can lead to the possibility of simplifying the mechanics while preserving haptic performance. The proposed approach consists of substituting the haptic actuation of one of the 3 rotational DOF by specially designed visual or auditory cues. We have carried out a user study where participants are asked to perform an accessibility task with the aid of different sensorial stimuli. The results of these experiments show that the performance obtained by visual or auditory substitution can be satisfactory for accomplishing specific tasks, although it does not meet the performance obtained with a full haptic wrist.