Design and implementation of a planar robot for food cutting

The aim of this thesis is to develop an unconventional cartesian plotter 2D for food cutting using the water jet technology. First of all we analysing the environment condition of work of the machine and we construct the machine according to the constraint carried out by the analysis. We develop an innovative placement of motors that allows to fix both motors at the machine chassis in order to have fewer moving parts than a traditional 2D plotter. The moving of the nozzle is made by a special configuration of belts and pulleys. The final result is a fully functionating machine with a Human Machine Interface. The thesis analyses the mechanical electrical and software part of the machine, listing the necessary requirements and explaining adopted solutions. Material selection for all mechanical parts followed standard HACCP rules and FDA requirements for North American market. In terms of mechanical design, we followed, as well, GMP (Good Manufacturer Practice) specifications in order to simplify cleaning procedures and minimize bacterial proliferation. The mechanism of the machine is based on two orthogonal linear guides actuated by step motors. Tro overlapped rails system has been implemented, where the above rail is responsible of water jet nozzle and the second one (placed just below the water nozzle) is used for water collection; the movement of both trays is synchronized. A static structural analysis was made as well in order to choose the needed stepper motors to fulfil required performances. The needed electrical hardware to control the machine was selected in accordance with actuators and intelligence we decided to use. More in detail we decided to control stepper motors trough PC/Arduino infrastructure, where the PC function as master and the Arduino (motor controller) as slave. The software is divided in 2 parts: the first is PC based and it is used to create the HMI, convert the G-code file into proper signal for the motor, implement the communication between the PC and the motors controllers. The second developed software is resident in the motor controllers and controls motor drivers. The PC and the motor controller devices communicate via USB using a handshaking protocol. The HMI is created using a graphic interface: all the function of the machine are linked here. On the graphic interface is implemented a real time cutting map and all buttons and widgets link to the main machine functions. They can be listed as below: - a G-code file selection - homing and base selection - joystick controller - limit switches reader The G-Code file, had to be translated to movement for actuators using an unconventional way. Since both actuators are placed on the fixed part of the machine X and Y translations are not independent but related, so in the software is implement a function dedicated to the conversion of the G-Code file into the actuators command. The computed actuators movement, coming from the PC was transferred to the Arduino device. This was transforming the command on steps and direction signals; signals were received, at the end, by LAM drivers that were actuating both motors accordingly. The generation of steps and direction commands are implemented into motor controllers, those are able to control the motor and check of the limit switch. the needed software for the communication is present as well. The emergency status is constantly checked, in case of emergency button is pressed controllers are activating an immediate stop of the system.