Final Report
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C-4P5 Bottle Filling Machine Aaron Landy December 3, 2013 University of Florida Department of Electrical and Computer Engineering EEL 5666 – IMDL – Formal Proposal A. Antonio Arroyo, Eric M. Schwartz TA Andrew Gray 1 1. Abstract 3 2. Executive Summary 4 3. Introduction 5 4. Integrated System 6 5. Platform 9 6. Actuation 11 7. Sensors 13 8. Behaviors 20 9. Conclusion 20 2 1. ABSTRACT This report details the design, operation, and development of a machine to automate bottling homebrewed beer. This stationary machine is composed of a grasping claw that traverses a horizontal track seeking empty bottles. When a bottle is found it is dragged into position beneath several filling and capping actuators in turn. The system is controlled by a master Raspberry Pi development board and two Arduino Mega microcontrollers. The platform is composed of a wooden structure to suspend actuators above the bottles, along with several linear motion axes based on Makerslide aluminum extrusion rails. 3 2. EXECUTIVE SUMMARY This report details the design, operation, and development of the C-4P5 beer bottle filling and capping machine. This machine automates the labor intensive but necessary task of bottling homebrewed beer. Cleaned, sanitized bottles are retrieved in turn, filled with beer, and then capped. The machine is stationary. A grasping claw traverses a horizontal track using a camera and a laser “tripwire” to find a bottle along the path of the track. When a bottle is found, the claw grasps the bottle and pulls it to the filling position beneath the filling and capping mechanisms. It retrieves each bottle in turn until all are filled and then returns to a waiting position. Bottles can be one of two standard sizes, 12 or 22 oz. A camera is used to determine the size of the bottle by calculating the cross-sectional area of the bottle's image and extrapolating volume and height. Three mechanisms perform the filling and capping. First is a stainless steel tube connected to the filling valve output. This tube is moved vertically (the machine's z-axis) into and out of the bottle. The second mechanism is a magnet. Before bottles are placed in the waiting line, each is manually sanitized and a cap is be placed over the top to prevent airborne contaminants from entering the bottle. Sanitizing and cap dispensing is done manually by the operator before starting the machine. Before filling, the magnet, mounted on a moving z-axis, is lowered into contact with the cap and then energized to pick the cap off the top of the bottle. After filling, the electromagnet is lowered back to the height of the bottle and de-energized, replacing the cap on top of the bottle. The final mechanism is a high-force linear actuator, also mounted on a moving z-axis. A capping bell will be mounted to the end of the actuator. When the actuator is engaged, the bell will be forced down around the cap, crimping it onto the top of the bottle. After filling and capping have completed, the finished bottle is moved out of position and the grasping claw searches for another bottle. C-4P5 is controlled by a master Raspberry Pi SoC board, which also drives two Arduino Mega 2560 slave controllers. A python application running on the Raspberry Pi handles serial communication between each microcontroller and provides user feedback through the Raspberry Pi’s LCD screen. Communication is conducted via well-formed serial packets through a tree- style master-slave network. The Raspberry Pi Camera Module, along with OpenCV-based C++ software, is used for bottle detection. The two primary linear motion axes are based on Makerslide extruded aluminum rails. A recycled ATX power supply unit (5V and 12V) and laptop charger (20V) provide power to the system. 4 3. INTRODUCTION Home beer brewing is a fun and rewarding hobby, but bottling beer can be a difficult and frustrating process. Many brewers quickly shun bottles in favor of kegging their beer, but not even those brewers that do keg can avoid bottling the occasional batch. The bottling process begins with cleaning and sanitizing each bottle. Then each bottle is filled by lowering a filling wand into the bottle until the level reaches the top. The wand is then removed (leaving a precise head space) and a cap is placed on the bottle. Next, a capper is used to crimp the cap on the bottle. Finally all bottles need to be cleaned, dried, marked or labeled, and stored for aging. While the all-day brewing process is creative and rewarding, bottling is a repetitive, dreary, repetitive task better left to machines than time-crunched hobbyists. To simplify the bottling process, I designed and built a beer bottle filling and capping robot. The objectives of this machine are to fill and cap each bottle with a precise amount of beer without contamination, oxidizing, or otherwise damaging or wasting the beer. Because homebrewers recycle bottles from different sources to keep costs low, the machine must accept bottles of varying size and shape, filling each with the Figure 2 Manual wing capper Figure 1 correct volume of beer. To ensure the Manual filling process is automated, the machine must find and retrieve bottles autonomously to free the brewer from feeding each bottle one at a time. This machine is stationary but mechanically complex, requiring several primary actuators, each mounted on moving linear axes. While large scale commercial bottling machines are commonplace in the beverage manufacturing industry, there are few examples of automated bottling equipment available to home consumers. However, while the overall system design is unique, the design relies heavily on open-source hardware and software systems which aided significantly in the design process and budgeting. Examples of these open systems include Arduino, Raspberry Pi, the Makerslide linear motion system, among others. This report details the design and operation of the C-4P5 automated beer bottle filling and capping machine. The report details the design and operation of the overall system, the physical platform, actuators, sensors, and autonomous behaviors. 5 4. INTEGRATED SYSTEM This machine is stationary. A grasping claw moves along a horizontal track (the machine's x- axis), using a camera, infrared range finder, laser tripwire to find a bottle along the path of the track. When a bottle is found, the claw grasps the bottle and pulls it to the filling position beneath the filling and capping mechanisms. It retrieves each bottle in turn until all are filled and then returns to a waiting position. Bottles can be one of two sizes, 12 or 22 oz. A camera is used to determine the size of the bottle by calculating the cross-sectional area of the bottle's image and extrapolating volume. This also determines the height of the bottle for later correct positioning of the capping mechanisms. Beer is fed from a large plastic bucket with a port in the bottom. A 12V solenoid valve opens and closes during filling. Fill volume will be determined based on calibrated flow rate. Three mechanisms perform the filling and capping. First is a stainless steel tube connected by flexible food-grade tubing to the filling valve. This tube is moved vertically (the machine's z- axis) into and out of the bottle. Because beer must be dispensed into the bottle with minimal agitation to prevent oxidation or contamination, the open end of the filling tube must be as close as possible to the interior bottom of the bottle. Filling Wand Varying bottle size: 12 oz or 22 oz Cap Bottle Electromagnet Claw Figure 3 Block diagram of physical design and operation 6 The second mechanism is a magnet. Before bottles are placed in the waiting line, each is manually sanitized using an acid-based food grade sanitizer and a cap is placed over the top to prevent airborne contaminants from entering the bottle. Sanitizing and cap dispensing is done manually by the operator before starting the machine. Before filling, the magnet, also mounted on a moving z-axis, is lowered into contact with the cap and then energized to pick the cap off the top of the bottle. After filling, the magnet is lowered back to the height of the bottle and de- energized, replacing the cap on top of the bottle. The final mechanism is a high-force linear actuator, also mounted on a moving z-axis. A capping is mounted to the end of the actuator. When the actuator is engaged, the bell is forced down around the cap, crimping it onto the top of the bottle. After filling and capping have completed, the finished bottle is moved out of position and the grasping claw searches for another bottle. When no bottles remain the claw returns to its starting position to await a start command. The block diagram below illustrates the overall design of C-4P5’s electronic systems. The Raspberry Pi SoC handles primary system control and image processing. It controls and communicates with two Arduino Mega 2650 microcontrollers, connected via USB. A python server handles master-slave communication, including forwarding commands from one Arduino to the other. The Raspberry Pi also executes a C++ OpenCV application to detect bottle size. Arduino boards were chosen for their rich feature and peripheral set, as well as ease and familiarity of development and availability of support. Each Arduino runs a nearly identical software platform. This platform is based on the standard Arduino bootloader and development environment, with the addition of the open source real-time operating system NILRTOS. This is an extremely small, statically allocated threaded operating system, which enables easy scheduling of concurrent real-time tasks.