Department Of Mechanical & Aerospace Engineering Sunseekers Heliostat

Department of Mechanical & Aerospace EngineeringSunseekers HeliostatSection 20722, Group 284HAlexander Lacerna, Elijah Crain, Jacob Jenkins,James Soto, Jennifer Brett, Joshua Brett, OliviaDodge

Department of Mechanical & Aerospace EngineeringHedgehog Concept and ValuePropositionLow maintenance and easily serviceableheliostat Motors, wiring, electronics, and most movingparts contained within the body Conventional bulkhead plug to exterior powersource Multiple ports of entry to service internal parts 3D-printed structural components

Department of Mechanical & Aerospace EngineeringKey Specifications 360 degrees of azimuthal rotation, 90 degrees of elevation Azimuth resolution: 0.08 Elevation resolution: 0.12 Survived winds of over 120 MPH in testing OTS power supply, motor drivers, stepper motors, mirror,sensors, limit switches, microcontroller, and motor drivers Compact size: 23.5 cm x 18.0 cm x 35 cm High resistance to back-drive

Department of Mechanical & Aerospace EngineeringWind Survivability Test Leaf blower (very high tech) 120 mph wind No damageVideo courtesy of Dr. Matthew Traum, University of FloridaRain/hail safety mode

Department of Mechanical & Aerospace EngineeringLaser Reflection Targeting Test

Department of Mechanical & Aerospace EngineeringMirror Mount DetailsPrimary MountMount FlanksTabs

Department of Mechanical & Aerospace EngineeringMirror Mount DetailsHinges to Upper HousingLinkage Hinge

Department of Mechanical & Aerospace EngineeringUpper Housing StylingMirror Mount HingesLinkage Clearance SlotShared CurvatureLid

Department of Mechanical & Aerospace EngineeringUpper Housing Electronics and Wiring ProvisionsHex StandoffsESP-32 MicrocontrollerWiring Clearance toLower BodyMotor Controllers

Department of Mechanical & Aerospace EngineeringLead Screw, Linkage, and Elevation Limit SwitchUpper LinkageChicago ScrewLower LinkageConstrained by Mirror MountBearingT8 Lead ScrewLinkageGuideLimit Switch StrikerLimit Switch

Department of Mechanical & Aerospace EngineeringLower Housing StylingSliding PanelAttachment to Upper HousingQuick-Release MountBulkhead Plug

Department of Mechanical & Aerospace EngineeringLower Housing Key FeaturesPower SupplyStepper MotorMotor Mount

Department of Mechanical & Aerospace EngineeringLower Housing Key FeaturesShaft BearingDrive ShaftWave GeneratorDrive BeltHarmonic TopHarmonic BaseLimit SwitchGuide Rails

Department of Mechanical & Aerospace EngineeringAzimuthal Rotation MechanismLimit SwitchDrive CapLimit Switch ActuatorBearing AxlesCentral Shaft

Department of Mechanical & Aerospace EngineeringInternal Wiring & Power Connections

Department of Mechanical & Aerospace EngineeringDesign Analysis – Mirror MountBending analysis to determine required thickness Flat plate model Resultant load from 90 MPH wind pressure acting with alever arm of 115 mm 𝜎𝑚𝑎𝑥 𝑀 𝑡2𝐼 7.5 MPa for n 212 𝐹 𝑞𝐴 𝜌𝑣 2 𝑙𝑤 17.5 N 𝐼 𝑏𝑡 312 𝑡𝑚𝑖𝑛 3.236 mm 𝑡 4 mm used in design

Department of Mechanical & Aerospace EngineeringDesign Evolution – Mirror MountMirror attachment method Originally planned to use mirror adhesive V1: 5 mm leg tabs V2: 10 mm leg tabsV1 mirror tabsV2 mirror tabs

Department of Mechanical & Aerospace EngineeringDesign Evolution – Mirror MountMount flank attachment method V1: Strong adhesive V2: M3 fasteners with pocket holes andhex profile Already used in other parts of the assemblyV2 mirror mount flank attachment

Department of Mechanical & Aerospace EngineeringDesign Evolution – Mirror MountCounterweights Slack observed in elevation control Counterweights added to maintain consistency Final production weights will be heavier

Department of Mechanical & Aerospace EngineeringDesign Analysis – LinkageBending analysis to determine required thickness Modeled as a cantilever beam 𝛿 𝐹𝐿33𝐸𝐼 Static loading force: 0.56 N Clearance: 0.565 mm Force to cause interference: 0.92 N

Department of Mechanical & Aerospace EngineeringDesign Analysis – Linkage KinematicsElevation range of motion Find required distance l1 linkage must move for a desired elevationangle θ. Convert l1 to a required step rotation by the stepper motor.Mirror Hinge 𝑙1 𝑙2 LSide View Schematic

Department of Mechanical & Aerospace EngineeringDesign Analysis - HousingInternal Temperature Analysis (for electronics)2 motor drivers (1A, 12V) 24 W𝑄ሶ 𝑜𝑢𝑡Voltage regulator (4.5 A, 12V) 54 WPower out to motor (2 A, 12V) 24 W 𝑊ሶ 𝑖𝑛 78 𝑊 𝑊ሶ 𝑜𝑢𝑡 24 𝑊 𝑄ሶ 𝑜𝑢𝑡 𝑞𝑟𝑎𝑑 𝑞𝑐𝑜𝑛𝑣 54 𝑊 𝑞𝑟𝑎𝑑 𝐴𝑠 𝜀𝜎𝑇𝑠4 𝛼𝐺 𝑞𝑐𝑜𝑛𝑣 ℎ𝐴𝑠 𝑇𝑠 𝑇 𝑊ሶ 𝑜𝑢𝑡ℎControl Box𝑊ሶ 𝑖𝑛 Solve for Ts: 𝐴𝑠 𝜀𝜎𝑇𝑠4 𝛼𝐺 ℎ𝐴𝑠 𝑇𝑠 𝑇 54 𝑊 0.03775 𝑚 20.395.67 10 8 𝑇𝑠 324.48 𝐾 51.33 𝑊𝑚 2 𝐾4𝑇𝑠4 0.311367𝑊𝑚2 20𝑊𝑚 2 𝐾𝑇𝑠 313.55𝐾

Department of Mechanical & Aerospace EngineeringCost Table Summary Prototype and 3,000-unit production run unit costPrototype CostMass Production Cost3-D printed parts 28.753-D printed parts 24.73Machined parts 13.72Machined parts 11.57Provided OTS parts 98.39Provided OTS parts 77.73Chosen OTS parts 39.14Chosen OTS parts 29.36Total cost 178.27Total cost 143.39Total cost excludingprovided OTS parts 81.61Total cost excludingprovided OTS parts 65.66

Department of Mechanical & Aerospace EngineeringSummaryThis design is focused on ease of construction as wellas ease of maintenance. With multiple points of accessall functional parts can be accessed and modified readily.Furthermore, this design is protected against itsenvironment with fully shielded motors and electronics,dust and debris is no concern. The orthogonal drivesystem operates well under the required 0.5 degrees ofaccuracy to provide optimal power output to the receivingtower.With readily removable paneling, integratedelectronics, and simple thoughtful design, this heliostat isoptimal for in field performance and maintenance.

Department of Mechanical & Aerospace EngineeringConclusionKey Features 360 degrees of azimuthal rotation, 90 degreesof elevation Azimuth resolution: 0.08 Elevation resolution: 0.12 120 MPH wind stability Compact size: 23.5 cm x 18.0 cm x 35 cm Wi-Fi controllability Low compliance Simple assembly and maintenance Shielded motors and electronics Cost is 28.39 under budget

Department of Mechanical & Aerospace Engineering Cost Table Summary Prototype and 3,000-unit production run unit cost Prototype Cost Mass Production Cost 3-D printed parts 28.75 3-D printed parts 24.73 Machined parts 13.72 Machined parts 11.57 Provided OTS parts 98.39 Provided OTS parts 77.73 Chosen OTS parts 39.14 Chosen OTS parts .