A Jury Test Methodology for the Assessment of User Rifle Trigger Tactile Preference

This paper presents a methodology to evaluate the preference of the user in relation to the trigger of a rifle. The selected approach is based on a Jury Test methodology which is a well know assessment method used in several fields, such as the subjective perception of acoustic noise or sound evaluation. In this case, the subjective test is applied to the tactile perception of the user to the stimuli of the rifle trigger, thus exploiting the possible means of interaction the human has with the object of interest. This approach is really important to define a complete user experience, helping to reach an innovative vision in the design and development of the product.As the Jury Test collects subjective preferences given by the users, a methodology is presented to correlate objective indices to these subjective preferences. The correlation is performed considering different parameters of the rifle trigger, previously measured with a specific experimental campaign conducted on real rifles, using an elasticometer.A correlation analysis is presented to find the optimal values of the objective metrics in order to maximise the subjective preference. In particular the highest values of the preferences towards the rifle trigger are correlated to the parameter of the trigger force and displacement. Best values have been found to be low force applied to the trigger and low trigger displacement. This method proves therefore to be efficient in correlating the parameters of this application case providing quantifiable feedback on the product in the context of a User-Centred Design.