Figure 3 Four pulleys arranged as the corners of a square.
Related Figures (7)
Fig.1 Block diagram of the Dosa Bot Before System architecture describes how dosa is cooked on this bot. To make the dosa on to the pan, first the required shape/image of the dosa is given as input through the Inkscape software. T creating a microcontro his software converts them into G-code fi ler board (Arduino) expedite the interfacing G-code files with the CNC shield. The motion in the caused by t he stepper motor rotation generated by the shield using G-code files. The motion of the b synchronized and pours the batter on the hot pan accordingly. Refer to the block diagram in Fig. 1. es by platform for the input images. Then the of the belt is CNC elt is As we know the place (X-Y coordinates) where the dosa batter falls on pan, we use inverse kinematics to find the rotation of the motors so that the nozzle of the batter beaker (End effector) reaches there. This calculation is done is the software and the instructions are given to the microcontroller which in turn transfers data to CNC. Then CNC rotates the motors accordingly. But to move the beaker to the particular location motors are connected with a belt which moves as the motor rotates. Instead of just connecting belt to the motors we use four pulleys around which the belt travels. Through this construction we will be able to achieve two axis movement with just two stepper motors. This arrangement is shown in the Fig.2 and Fig.3 where beige colored parts are pulleys. Fig.2 Pulleys around which the belt travels. Fig.5 Motors are moving in same direction (clockwise) so th beaker will be moving in X-axis (here towards right) Fig.4 Motors are moving in opposite direction so the beaker will be moving in Y-axis (here downwards) As seen in Fig.3 the pulleys are arranged as four corners of a square. Hence we call it a square arrangement. The belt travels along these four pulleys and follows a pattern of plus (‘+’) like structure. This can be well explained through the following figures. Refer Fig.4 and Fig.5 Fig.7 Solidworks design of HD bot view 2 Fig.6 Solidworks design of HD bot view 1 After the entire mechanism is setup, the beaker moves to its destination location and its nozzle gets opened by the servo motor. Batter falls on the hot pan. This servo motor operates according to the instructions given it. There is an air pump which pumps air continuously into the beaker to create pressure in order to push the batter. The heating of pan/thawa is achieved through induction coils placed beneath the pan. The temperature of the pan can be controlled using the control panel. After finishing the dosa the beaker moves to its original position and holds.
