Discussion and Users Test
Abstract In this chapter we will describe the characteristics of the developed system in terms of: performances, modularity, portability and implementation costs. In order to perform an accurate analysis of the rendered trajectory and of the usability of the system we will describe the user tests performed and we will analyse their results.
Characteristics of the Tactile Display Developed
The Tactile Display that has been developed through the modules with direct actuation system allows us to overcome the main issues of the previous solutions characterized by the indirect actuation approach. These issues are mainly related to the mechanic plays, to the elements stiffness and to the impossibility to change in real-time the nominal distance between the control sectors. The direct actuation approach requires that the servomotor in charge of moving the element Arm2 (6.2) has to be placed directly on the joint instead of at the module base.
In the module with indirect actuation system it has been decided to arrange all the servomotors of the articulated system on the module base in order to avoid inertial loads during the module movements.
In the second version, the Arm2 servomotor is placed on the upper extremity of the element Arm1 and it moves together with the component during the operations of the articulated system. This feature increases the influence of the inertial loads with respect to the previously designed version.
However, the design aiming at increasing the stiffness and reducing the mechanic plays allows the module to support the inertial loads without incurring in unwanted vibrations. Furthermore, the obtained module with direct actuation approach presents lower value of width (along transversal direction), thus allowing decreasing the minimum nominal distance among the control sectors.
The configuration with direct actuated system has been designed in order to allow the control sectors to slide under the strip and change in real-time the nominal distance between control sectors. Thanks to the developed control, which allows the user to choose among three different kinds of control points management, the whole system is able to perform the rendering of the trajectory always in the best condition.
© The Author(s) 2017
A. Mansutti et al., Tactile Display for Virtual 3D Shape Rendering, PoliMI SpringerBriefs, DOI 10.1007/978-3-319-48986-5_7
The designed module has been developed in three identical copies and it has been mounted on the desktop station, which includes the rail and the rank needed for the longitudinal displacements. The station is also equipped whit the control hardware and the power supply components.
As mentioned in Sect. 3.5, the system has to comply with the following general requirements:
- • it has to be performing in terms of the potentiality of representing a surface. This requirement is represented by the minimum curvature radius achievable and by the resolution and the accuracy of the system. These parameters depend on the number of the control points and the distance between them;
- • it has to be modular, so as to be customized according to the kind of surfaces with which the designer and/or the design studio usually deals;
- • it has to be low cost, so as to be affordable for a large number of design studios or even for designers who work on their own;
- • it has to be in a desktop and portable version. This will ease the introduction of the system in the everyday working life as it happens for a mouse or a keyboard.
All these requirements will be analysed in the following sections, underlying how the developed Tactile Display meets them.