Positioning System on X-Y Plane
The planar articulated system is made up of the components named Arm1 and Arm2. The servomotor Servo Arm 1 rotates Arm1 by means of a four-bar linkage composed of two connecting rods and a rocker arm. The transmission system of Arm2 is more complex because of the distance between the actuator and the component. In order to
Fig. 5.3 Arm1 actuation mechanisms
transmit the motion to Arm2, we have designed a mechanism made up of a four-bar linkage, which connects the actuator to the underlying synchronous pulley.
Torsion and Tangency Rotation Systems
On top of Arm2 a tilting system is hinged. It rotates the hinge Rz3, thus allowing the control sector to perform the proper movement that enables the torsion with an angle between ±45°. This is driven by a servomotor housed in a seat, which has been developed inside Arm2 and connected to the tilting system through a four-bar linkage. Inside the tilting system, we have placed the servomotor connected directly to the control sector. The servomotor actuates the degree of freedom Rx in charge of changing the tangency of trajectory to the control sector with an angle between ±90°. To obtain a system simple to control, the rotation axes of both rotations have to lie on the same plane. This feature has been lead many difficulties during the design of the modules top part. However, by an appropriate development of the seat of the tangency control servomotor, we have been able to achieve also this important feature.
Translation System Along Z Axis
The translation along the Z axis has been represented as a runner and has been obtained by developing a carriage sliding on a rail. To move this degree of freedom,
Fig. 5.4 Torsion and tangency transmission systems
we have used a rack-pinion system where the gear wheel is driven by a servomotor fixed on the basis of the module. The rack is fixed to the frame. By actuating the servomotor, the entire module can move according to the direction Z. This movement allows changing the distance between the control sectors and, in this way, it is possible to represent a trajectory with greater precision (Figs. 5.3 and 5.4).