DESIGN ACTIVITY 1. AN INTRODUCTION TO LABVIEW & LEGO MINDSTORMS (LABVIEW 1) Overview Develop a proof of concept prototype for an experimental solar panel positioning system. The system will be able to track the daily changing position of the sun and be self-correcting should it be inadvertently moved. You will need to demonstrate your ability to formulate a work plan, generate a functional solution using LabVIEW. Figure DA1-1: The tracking of the sun by a set of solar panels Image source = http://www.allearthrenewables.com/products/solar/ Scenario Technology to make solar panels efficient and cost effective continues to advance, making them an excellent method for remote sites to have long lasting power. For example, these panels are being used for remote telecommunications stations and in developing countries without the larger centralized power infrastructure. Image Source http://www.wholesalesolar.com/products.folder/systems-folder/REMOTETELECOM.html Src= http://kathyprice.typepad.com/remodelingblog/page/2/ (Sources - http://elth.ucv.ro/fisiere/anale/2006/3_6.pdf) Figure DA1-2: Examples of solar systems in remote locations Maximum efficiency of the panels occurs when the sun’s rays are perpendicular to the panel. The two major features determining the correct angle of the panel to the sun are subject totime of day and time of year. The first figure illustrates the Solar Azimuth motion of the sun which relates to movement of the sun throughout the day. The Solar Declination motion is relative to height of the sun off the horizon which has a peek noon day height that changes throughout the year. (a) (b) (Sources - http://elth.ucv.ro/fisiere/anale/2006/3_6.pdf) Figure DA1-3: The angles for Sun; a) Solar Azimuth; b) Solar Declination The small startup company you just joined is exploring the potential of constructing a low cost tracking system that could follow the sun’s motion to maximize the positional efficiency. Several experiments have been done to demonstrate that the Solar Declination is not that sensitive of a factor (i.e., the changing noon day height for each season). It appears that simply repositioning the panel each season is sufficient and only results in a 2% loss of efficiency across the season. However, simply fixing the solar azimuth angle permanently to the south averages a 30% loss of potential energy that could have been collected if the panel tracked the Solar Azimuth motion. Potential models that address this issue might be based on time, while others rely on sensor inputs. Another major concern is that the system could temporarily loose power, be bumped or need correction from time to time due to inaccuracies. Therefore, one of the goals is to produce a self-correcting system that can automatically reset itself to track the Solar Azimuth motion of the sun. Front View Side viewFigure DA1-4. Conceptual design of the potential system simple lens system to concentrate light from the sun into an intense source of light. The CEO is looking for a quick feasibility study of potential design options and is setting up multiple teams to conduct a deep dive into the positioning system. She anticipates reviewing these conceptual designs by teams coupled with their rough physical prototype to illustrate the proof of concept of the positioning logic for this system. She expects to see the system start up, quickly establish its initial position and then demonstrate successful tracking. Her goal is to quickly assess how well her teams can generate, explore, build and test a design and then quickly report the issues and opportunities associated with the conceptual design. She knows this will not be the final design, but hopes that it will be rich with innovation and insights. Pre-Activity Assignment (Individual Basis) • Read Design Activity 1 • Build the Solar Tracker from your Legos (you can program it during the class) • Watch LabVIEW Videos 1 to 13 or as your Instructor indicates. Task 1: Implement Your Solution (remainder of class) Your team will construct a mechanical prototype that demonstrates the major functionality of the conceptual design, including its ability to self-correct solar azimuth angle. For the sake of consistent testing, each team will assume 12 hours of sunlight in the day and that the sun rises straight east and sets straight west. For demonstration purposes assume each hour in a day is simulated as 3 seconds of real time (i.e., a 24 hour simulation will equal ~72 seconds of real time). The prototype only needs to support the basic mechanism to operate the positioning system. The solar panel will be simulated using a Lego Mindstorms light or color sensor You are required to develop your prototype mechanism using components from your EV3 kit and any extra parts provided. All EV3 programming will be done using LabVIEW (see Appendix 1 for specific details/). The system should be able to track, with some measurable amount of reliability, the sun throughout the day. You should provide evidence of its ability to track the sun, including its ability to self-correct solar azimuth angle, with measurable data that is reported in your design notebook. Deliverables To document the conceptual design process and the creation of your prototype, each team should create a simple loose-leaf paper “design notebook,” which will be turned in at the end of this Design Challenge. All aspects of the prototype creation process should be documented in this “design notebook,” such as mechanisms used to understand the problem, listings of solution constraints and criteria, assumptions made, sources of evidence, project management decisions, etc. 1. Once you have developed your control algorithm, you should create a LabVIEW script (DA1_SectionYY_teamXX.vi) that will perform the motion control algorithm.Your analysis of this problem should be included in your design notebook. Creation of any graphs you deem appropriate can be done in LabVIEW or Excel. 2. Develop an analysis method that provides evidence that the system meets the desired performance requirements. Solar Panel Structure (to be built prior to class) Left Side View of the Structure with the Solar Sensor at Rest Front View of the Structure Left Side View of the Structure with the Sensor in the Active Position Rear View of the Structure Right Side View of the Structure with the Solar Sensor in an Active Position Solar Panel Programming Instructions Note that many of the
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