Module with Indirect Actuation System
Abstract This chapter presents the concept of the solution based on indirect actuation approach. This configuration aims at positioning the control points of the rendered trajectory in the space. The degree of freedom of the device are controlled by using indirect actuation systems, which are described in the following paragraphs. Moreover in this chapter we will describe the performed kinematic analysis, the design of the components and the developed prototype. In this manner, it has been possible to evaluate the pros and the limits of the presented solution.
Concept of the Module
In order to design the module in charge of positioning in the space the control sector according to the developed kinematic scheme, we have firstly defined a conceptual development that allows us to study the transmission system. The absolute configuration requires the control sector to be placed in the space with respect to an absolute frame of reference. Therefore, to obtain the displacements needed for positioning the control sector according to the X-Y-Z coordinates, large displacements are needed. As shown in Figs.4.9 and5.1 the configuration of the kinematics has been specifically designed for this purpose. To place the control sector in the Transversal plane (X-Y) we have designed two degrees of freedom arm made up of the elements Arm1 and Arm2. To perform the displacements along the Z direction we have adopted a linear degree of freedom obtained by means of a runner that slides on a rail. Since the actuation of these degrees of freedom, in particular for the X-Y positioning, requires large displacements, the dimension of the elements Arm1 and Arm2 create an arm, which will involve an higher value of motion torque to move the mechanism. For this reason, the motors that move the articulated system by rotating the hinges RZ1 and Rz2 have to provide a high torque and, as a consequence, a larger size. In order to avoid high inertial loads and excessive dimensions of the components, which move within the workspace, we will try to place these motors at the basis of the module.
© 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_5
Fig. 5.1 Concept of the module