Heliobot

Felipe Peceguero, Jorge Orozco, Kfir Gluzberg

Faculty: Marta Malé-Alemany, Victor Viña, Cesar Cazares

HeliobotAutomated Construction using Solar-Concentrated Heat

1:1 Design Research

This is the full scale research and development of a machine for digitally controlled construction. Our research aims to prototype an intelligent machine that utilizes and responds to the sun’s energy. We are concentrating solar energy for operations of burning, heating, and cutting in the preparation of materials and/or elements for assembly. The robot is also intended to rely on solar energy for electrical power, making it capable of operating autonomously.

Three components compliment each other to provide the Heliobot with the ability to execute limitless two dimensional paths for heating. An upper portion is exposed to the sun and utilizes a lens and mirrors to concentrate photons to a controlled location. This is mounted on a chassis equipped with an omni-directional mobility system. Finally, its intelligence lies in data collected from a path recorder and light sensor which allow the robot to respond to its environment in real time.

Index

1 Introduction

2 Material Studies

3 Electronics

4 Robotics

5 Design Explorations

6 Conclusions

Abstract

Site environmental conditions are constantly in flux.

Off-the-grid

Fundamental

Circumstantial

Result

Open source design and fabrication allow for specification.

Off-the-grid

A CNC inprecise execution.

Digital cutting technologies have revolutionized the way in which we manufacture even our most ubiquitous commodities. These machines are consistently being refined to produce more accurate cuts. Technologies now include up to five axes, combined cutting tools, and material additives which can recreate any cut. However these are all restricted to functionality under ideal conditions. These machines often include highly sophisticated construction and parts. Their operation assumes a perfect environment. This goes as far as such machines which operate in closed environments such as the laser-cutter pictured below-right.

Automated Cutting TechnologiesPrecedent Technologies

Above and to the RightWaterjet machinery capable

of cutting many metals

Above Laser technology is often

used to make precision otherwise impossible

diamond cuts.

Above and to the RightLaserjet technology in

varieties that cut between one and five axes

TowerSolar Power Tower in Bartow, California.

Parabolic DishPower plants using this technology are not in commercial use yet. This is an experimental installation .

Stirling EngineThis engine moves a turbine by heating a compressed gas.

Heat is often applied to materials in a variety of construction techniques. It is the great amount of energy necessary to generate this heat that makes these process difficult or costly to apply. It is therefore a challenge to attain a heat-based construction process that is also self-sufficient. One such system is the technology used in solar power plants today. By concentrating sunlight, these plants are able to create massive amounts of heat and energy at little cost and effort.

Solar ConcentrationHeating Technologies

The varying levels of light concentration surrounding the focal point can be used to heat materials to varying

degrees.

BelowFresnel lenses are commonly used for image enlargement

Light RefractionConcentration Principals

Both lenses below demonstrate the concentration of all the light reaching the lens surface into a single focal point. The point’s location is determined by the curvature of the lens surface and is also the point of greatest heat.The depth of the convex lens can make these lenses heavy or thick. Conversely, the fresnel lens below is an alternative that corrugates the lens surface. The convex curvature is collapsed to provide a lens that can become nearly flat. Fresnel lenses are available in plastic sheets which are inexpensive and light. They also have a crucial advantage of being easily transportable to accompany the mobility of the robot.

Focal Point

Convex Lens

Focal Point

Fresnel Lens

There are two principal methods in which we tested possible lens configurations. Both reflect the concentrating light in order to relocate the burning focal point. The first method uses a single mirror but can only function for limited hours in the day. The second method refracts the light twice in order to continuously burn throughout the entire day and in any location.

Controlling the Focal PointCan we direct heat to a given surface?

Sunlight

Sunlight

Lens

Lens

Target Material

Target Material

xy

y

Mir

ror

2

BelowPlan

Bottom LeftLens configuration 2

LeftLens configuration 1

Mirror 1

Lensx1

x2

y

Material Exploration

This is a test that we did on a piece of nitinol used in mag-

ic tricks. It bends at room temperature and then returns

to it’s shape as the jack of spades when heatedx .

LeftMoving fashion design by

Mariëlle Leenders. Embeded with wire

This mixture of nickel and titanium can be taught to remain in a particular form. When the material is cold it is malleable and can be easily deformed. However as soon as it is heated, it returnes to it’s pre-taught shape. Currrently this material is predominantly used in the dental and magic industries.

NitinolHeat memory alloy

RightPavel Hladik proposes a truss

system based on repeating nitional components.

LeftPlastic densification occurs regulary when heated against a surface. Here, resulting lines of density create a structure on which the remaining plastic can span.

PET Demonstrates structural properties at small scales. BelowMold used for PET forming

Thermoplastic Resin be-comes quite rigid and is easy to control under heat. However, the cost of this ma-terial makes it a prohibitively expensive option.

LeftSample formed in hot water

RightSample formed under solar concentration

Achieving 3-Dimensional Forms with Heat

Clear Plastic Sheet

White PVC Foam

Soap

Metallic Plastic Sheet

Synthetic Non-woven Fabric

Plastic Hose

Rigid Insulation

Cardboard

Sugar

Soap

Sand

Wood

Applying a Heat Gun Using a Laser Cutter Focussing a Magnifying Glass

1

High heat: Fabric tight Shrink-wrapped a form and became smooth. Low Heat: Fabric loose formed bubbles that could be controlled along protrusions on form.

Lines of bubbles formed with loose fabric along form

Heat material and apply pressureto push onto form.

Heated soap begins to bubble all along surface. Bubbles remian when cooled.

Point of melting becomes smooth. Heat may be too low to make 3D results.

Melting the seam between to sheets to form one surface.

Flat surface shrunken again form. Ridges form with lines of contraction stresses.

Openings melted into � at surface. Lines of form melt to make dense plastic lines.

Flat surface implodes immediately in microwave. Flat surface under low heat immediately contracts.

Metal rings heated and pressed into plastic. Veining around rings during contraction.

Fibres melt and fabric contracts and bends. Becomes solid when cooled.

Tube is melted in one area and air is blown to form a bubble.

Becomes a solid that can support itself

Bubbles and keeps form

Lighter colour; some cohesion

Colour becomes darker. Material can be moulded.Very low melting point.

Surface is scorched and can be burned through.

Wood becomes scorched.

Heat of focussed point is relative to surface area of lens. Fresnel lens is an inexpensive and � at plastic option for large focussing surfaces.

A handheld or mobile cutter is possible after seperating the laser diode.

Heat material and pinch to achieve a form.

2 3 4 5 6

Design of the Heliobot as a solar tool is makes it inherently reactive to its environment. It is therefore to embed an intelligence into the robot; an ability to respond to external conditions independantly. It is conceivable to employ this technology in the focusing system associated with the lens and mirror. Based on photovore design, the lens and mirror could continuously search for and focus the sun by treating the connection between circuit components as neurons in the brain

Thermo-formed PlasticsAttributes of heated plastics

Above and Bottom RightUsing wax in a vertical

position gives clean edges at the surface as wax drips

away. However, when heated horizontally and then emptied, forms can become

symmetrical.

Middle These are two images of

the casting process for the base form of the wax. It is conceivable to heat water

with solar power for this end.

These wax tests attempt to suggest a site-cast material for various construction elements. The Heliobot can be imagined as catalyst for an economic and organic wax casting system. As well, the vertical test above demonstrates the possiblity of creating a type of wax deposit system.

States of Molten WaxCasting heated forms

Left and AccrossThese two tests demonstrate the velocity of the wax melting.

Far LeftThe flower shape was derived using the horizontal melting method. The lower crevasse was derived vertically.

LeftThis is the wax cast in plaster.

Far Left & MiddleThese shapes were formed by the horizontal method.

LeftThis form was made with the vertical melting method.

Relation to Wood Grain

RightBurst by System Architects installed here at the MoMa,

demonstrates the ease of construction allowed by

prefabricated elements. The wood elements used here

have been CNC cut.

Double Passes

Single Passes

10 cm - 1:40 min

7 cm - 4:35 min 7 cm - 5:15 min

5,5 cm - 7:49 min

7 cm - 1:52 min 7 cm - 1:36 min

4 cm - 5:30 min 4 cm - 5:15 min

Plywood is already a common construction material and is available in low-emission and environmentally low impact varieties. Since this material is manicured and processed, its planarity and smoothness make it a blank canvas for various CNC or laser cut projects. Burst is one such project which demonstrates a prefabricated CNC project that can be rapidly assembled on-site. Our tests provided insite into the slow cutting speed for this material. Its density makes cutting impossible with passes on only a singe side of 3 mm. plywood. However, with some burning (considering a single pass as a ‘score’), it is possible to snap pieces with a reasonably even edge

Plywood Material tests

Architects like Shigeru Ban have introduced paper into the contemporary architectural vocabulary. These material tests explore the potential properties that can be utilized to create structures with burning and bending. Burning tests generally demonstrated that while a steady line could be achieved, there would always be a rough edge. However, depending on the intensity of solar radiation and wind, burns would often continue travelling through the corrugations even after the focal point had passed. The tests below also demonstrate the changing flexibility of the cardboard in bending depending on the direction with relation to the corrugation.

Corrugated CardboardConsidering and utilizing cardboard characteristics

LeftBurning perpendicular to the corrugation

LeftMaterial rigidity in bending provides different flexibility with relation to corrugation

LeftThis set of repeated pathes demonstrate the irregularity of material burn depending on solar radiation and environmental conditions when using untreated cardboard

These time-lapse images were taken after the intial

burn was made. They demonstrate a spread

velocity and that a great deal of the material is consumed

after the initial burn.

The samples at right demonstrate the speed at which a 10 centimetre line

is burned. It is also obvious that material consumption

occurs in the direction of the cardboard corrugation.

BelowA piece scored on both

sides is nearly completely consumed.

RightTime Lapse in 5 s. Intervals demonstrating attributes of

ink use.

RightThese tests attempted to

control the direction of the material consumption.

Howecer, consumption still corresponded to the

corrugation below.

30 s26 s

25 s 25 s

23.5 s18 s

24 s

14 s

20 s. 15 s. 10 s. 20 s.

These samples burned a black line on the paper. While

their ignition is faster, the overall rate is comparable to

tests with no ink. The dots did not enhance the burn.

Below Two panels covered in wax, and in wax and talc. Both intumescent materials applied thinly to reduce burn rate.

Left AboveThe process of creating paper pultp and sifting it allowed us to customize materials for several tests.

LeftThese are stills from a film of the extraction of a cut element from a sheet of treated cardboard.

Initial tests found the cardboard too flammable and uncontrollable. However, by using wax as an inhibitor the line could become much finer. A final step was to add talc to the admixture. Talc is an inexpensive and common intumescent substance. It helped to further slow damage created by consumption of the cardboard. The following step would be a set of exercises in controlling the intumescent attributes by creating our own paper empregnated with wax or metal in order to control or alter the burn. The resulting papers andburn tests can be found on the following page.

Refining a LineExperiments with Intumescence

Electronics and Intelligence

Data (i.e. EcoTect)

Programming (Arduino)

BEAM (Biological, Electronic, Aesthetic, Mechanical)

Sensors

Trajectory Response Intelligence

In order to understand which electronics and software would be best suited to our needs it is important to understand the different impacts that they could have on the user interface and resulting fabrication. There is a gradient of intelligence that can be embedded including an integration of more than one system approach.

Methods of AutomationHow much intelligence is efficient to embed

BEAM (Biological, Electronic, Aesthetic, Mechanical)

int ledPin = 13;int motor1PinA = 12;int motor1PinB = 11;int motor2PinA = 7;int motor2PinB = 5;int switch1Pin = 10;int switch2Pin = 9; int switch3Pin = 6; int switch4Pin = 4;

// variables will change:

void setup() { // motor pin as ouputs pinMode(motor1PinA, OUTPUT); pinMode(motor1PinB, OUTPUT); pinMode(ledPin, OUTPUT); pinMode(switch1Pin, INPUT); digitalWrite(switch1Pin, HIGH); // internal pull up resistor pinMode(switch2Pin, INPUT); digitalWrite(switch2Pin, HIGH); // internal pull up resistor

pinMode(motor2PinA, OUTPUT); pinMode(motor2PinB, OUTPUT); pinMode(switch3Pin, INPUT); digitalWrite(switch3Pin, HIGH); // internal pull up resistor pinMode(switch4Pin, INPUT); digitalWrite(switch4Pin, HIGH); // internal pull up resistor Serial.begin(9600); Serial.println(“hello world”);}

void loop(){ Serial.print(digitalRead(switch1Pin)); Serial.print(digitalRead(switch2Pin)); Serial.print(digitalRead(switch3Pin)); Serial.print(digitalRead(switch4Pin)); Serial.println();

if (Serial.available() > 0) { int dataIn = Serial.read(); if (dataIn == 97) { rotateMotor1Clockwise(); delay(50); stopMotor1(); } if (dataIn == 100) { rotateMotor1AntiClockwise(); delay(50); stopMotor1(); } if (dataIn == 106) { rotateMotor2Clockwise(); delay(50); stopMotor2(); } if (dataIn == 108) { rotateMotor2AntiClockwise(); delay(50); stopMotor2(); } }

// check if the pushbutton is pressed. // if it is, the buttonState is HIGH: // AQUÍ VA LA PAUSA

if (digitalRead(switch1Pin)== LOW) { digitalWrite(ledPin, HIGH); rotateMotor1Clockwise(); }

if (digitalRead(switch2Pin)== LOW) { digitalWrite(ledPin, HIGH); rotateMotor1AntiClockwise();

AboveArduino and circuit with four button controls

BelowPreliminary robot with elements in two axes of

Below is a sample of the programming script sent to the Arduino.

In this workshop we connected basic circuits involving light sensors and controlled motor movement. It was clear that the Arduino interface could be fine-tuned to meet our needs with regards to proportional lens movement and possible implementation of sensors.

Initial CircuitsArduino workshop with Victor Viña

Design of the Heliobot as a solar tool makes it inherently reactive to its environment. It is therefore possible to embed an intelligence into the robot; an ability to respond to external conditions independantly. It is conceivable to employ this technology in the focusing system associated with the lens and mirror. Based on photovore design, the lens and mirror could continuously search for and focus the sun by treating the connection between circuit components as neurons in the brain

Research in Intelligent RoboticsBEAM Robotics(Biological, Electronic, Aesthetic, Mechanical)

Photovore(attracted to light)

Photophobe(repelled by light)

PV CellCollect Power

CapacitorStorage

Light ResistorSense and Limit

TransistorsAmplify and Smooth

MotorPower Use

Ground

This circuit is a welded ver-sion of the one in the diagram accross and above. pictured accross. The capacitor gathers energy which, when released, activates a small motor that causes the BEAM bot to ‘hop’

LeftA typical photovore circuit www.solarbotics.net

Mobility TestingOmnidirectional Robot

Omnidirectional Robot

OUTPUTINPUT CODE

design robotinstructions

software analysisarduino

performancecut path

As a preliminary step into understand the relation between design input and actuator response, a miniature device was created. The device used six motors to achieve omni-directional movement. The following tests allowed us to compensate for physical properties of the robot construction which hindered correct execution.

Left and Bottom LeftStills from clips taken of the robot performance: rotation, acceleration & speed.

Machinic Design

yº

1/2 x

1 x

This prototype intended to minimize the amount of power necessitated by the machine. The lens and mirror must rotate at two different rates along a single axis. A set of gears allowed for this movement. However, the mass and friction of the MDF parts prevented this prototype from functioning.

Prototype V. 1.0Two Motors and Three Velocities

While this prototype was unable to function autonomously, it did posess the correct proportions for to be used as a solar concentrator.

1/2 x 1 x

Following V1.0, several changes optimized the robot’s movement. The material was changed to acrylic which created less friction and reduced the robot’s mass greatly. This prototype also utilized light sensors. Both the stepper and servo motors were connected to light sensors allowing 3-Dimensional movement to locate the light source.

Prototype V. 1.1Three Motors and Light Sensors

Without fine-tuning and calibration of the sensors, this protoype was able to locate a light source, however, it could not create and maintain a focal point.

After the mechanichal improvements of previous version, this 2.0 version was designed joining the tool, now with 2 motors, one servo and one stepper and the mobility unit, with 6 motors, 3 hackd servos and 3 servos. The new tool allows the robot to work in every location and every time. The mobility unit allows movement in all directions.

Prototype V. 2.0Eight Motors and Omni-Directional Movement

Manual controls allowed the robot to maintain the focal point and a script determined the movement and the trajectory of the robot.


Prototype V. 2.1Two Motors and Two Velocities plus moving device


Prototype V. 2.1Two Motors and Two Velocities plus moving device

Since the basic principle of this bot relies on the lens and mirror system, there are many possible variations relating to the bot’s construction and characteristics of the lens system.

As an initial step to a project utilizing this device, the user approaches a website that contains necessary resources to obtain a customized bot . The interface draws on two main databases in order to determine the design of the final bot. There is one which is a catalogue of cutting materials used to determine the heat needed and surface that the robot will need to traverse. The second relates to weather and uses localized historical weather data to determine what stamina the robot will need and any other physical characteristics that may be effected (permeability, construction material etc.). Meanwhile, existing and functioning Heliobots can continue to relay project and sensor data back to the databases in order to continuously refine and improve new users’ customization.

Robot TypologiesOpen source and personal fabrication

project surface

robot construction

RightMap of world earth terrains

Far RightMap of world solar radiation

levels

RightThe given project material

as determining factor in lens attributes

BelowSample types for heliobot

robots with altered possible lens size and focal lenths

Robot TypologiesOpen source and personal fabrication

Any resulting cut produced by the Heliobot is necessarily a result of the precise environmental and material conditions at a certain place and moment in time. This is a natural condition since the tool relies the sun’s power to heat the cut-line. However, it is also enhanced by its realtime response.

While a full weather station could properly equip the Heliobot to more precisely recreate and cut-line, as few as two basic sensorial parameters can provide conditions for a safe and true cut. A solar radiation sensor could equip the bot with the ability to prevent excessive burning or fires. It could, therefore, also help maintain a consistent cut by speeding up when radiation is increased and vice versa.

A second sensing system that would be necessary to properly execute a given trajectory would be a path-tracker. Such a system would record the accomplished path made and relay back to computer. This would allow the Heliobot to locate itself with relation to completed tasks at any moment.

Sensors & Intelligence Momentary environmental response

Design Avenues

2On site, material and

trajectories parameters are used to optimize a

design solution based on known material behaviour in response to various site and

robotic conditions that are pre-determined.

4The treated pieces of the

design should be assembled manually.

HELIODESIGN

Heat is used in a variety of construction techniques in tandem with materials. It is however often very energy demanding to create heat and we searched for a self-sufficient system that can create heat. Today there are several functioning and several test solar power plants. these use basic optics to gather heat generated by the sun to create energy.

How Does a Heliobot Design Work?Sequence of Design and Construction

1Various client specific

paramters can be used to optimize and personalize

the design of any Heliobot. Material properties, project

trajectories and local climate all influence design.

USER

HELIOSOFT MATERIALHELIOBOT

3Once the material is placed on site, the performance of

the Heliobot is reactive to its enviroment during the cut

process.

MATERIALPERFORMANCE

These case studies represent possibilities for cardboard architecture whose construction and geometry are not directly linked to their site. The chinese disaster housing above proposes a design that is light weight and easily packed for shipment. Every component of the cardboard packaging is using in the final construction. The geometry proposed is intended to maximize material use and create a temporary living space. Meanwhile, the project below, designed for and exhibited at the Venice Biennale in 2008, represents the use of cardboard as a building element such as a brick. While this geometry increases structural performance, it increases the total perimeter of each individual building element. Finally, Stutchbury and Pape’s Cardboard House offers a novel geometry which allows for more permenant and weatherproof design.

Design with CardboardCase Studies in Cardboard Construction

Below and Below LeftIwamotoScott created this cloud form out of repeated Voussoir forms cut, scored, folded, and attached. This is a 3D tesselation

Below and Below LeftStutchbury and Pape’s 2005 proposal: Cardboard House

LeftThe Gifu Prefecture Regional Disaster Management Center has designed the Octagon (41 kg. in two boxes). The home is easily transported and can be rapidly assembled.

RightThe neste trajectories for a

small dome

This construction method treats cardboard as in deposition machines. Any contour can be cut and stacked allowing for little accuracy in order to achieve quite solid structure. The preferred orientation of a burn will also mean that the exterior surface would usually be sealed (air cannot travel perpendicular to the corrugations). This techique also utilizes a great deal of material. However, the low accuracy necessary makes low-grade cardboard an option for construction.

Cardboard DepositionContour construction

RightA sample of stacked and contoured solar-burned

cardboard

BelowContouring as architectural

approach

It is possible to build using modules cut and engraved by the robot. By cutting and engraving on cardboard, the robot generate easily foldable modules this modules can be used on the construction.

Assembly modules Assembling indivitual of developed pieces

LeftThese examples demonstrate the option of creating a cardoard brick. This method would require much support for 3D constructon.

Left and AboveIn order to maximize the material utilization and to develp a digital tectonics system according to the material optimization, this system was developed. The larger amount of cuts happen in the direction of the cardboard corrugation. By this method the imprecision level is reduced.

Where joint design often relies on the perfect fit between two elements, the Heliobot necessitates joints that take advantage of the unique inaccurate edge that results from the solar heating process.

Joint DesignAssembling Inaccurate Pieces

On site, material and trajectories parameters are fed into Heliosoft, a customized Heliobot software.

Folding geometries are traditionally used in many architectural solutions. Here, the ability of the machine to cut and score as two seperate executions allows for many folding geometries to be viable design options. However, material tests have shown that cuts which are perpendicular to the corrugation are haphazard. This makes many folding geometries in practical to pursue with the Heliobot.

FoldableFolding scored pieces

On site, material and trajectories parameters

are fed into Heliosoft, a customized Heliobot

software.

On site, material and trajectories parameters

are fed into Heliosoft, a customized Heliobot

software.

1

2

3

4 5

6

78

9

10

1112

13

14

15

3

1

2

79

5

6

4

8

The strength of these individual processes is based in their ability to utilize the material and machinic characteristics of the Heliobot execution. These attempts utilize the strengths of previously studied assembly systems to arrive at stronger and more efficient solutions.

The following are tests for a scaleless construction elements including a fold and join as well as two levels which allows the systems to multiply easily into 3-dimensions.

Combining TypologiesBuilding Elements Using Joints and Folding

The scenarios that we envision are those in inaccessible places or those that lack proper infrastructure for traditional construction.

This scenario employs a one construction element design that utilizes a fold and joint. The resulting form is a continuous cloud structure made of a 3D tesselation of the part. This provides a great variety of spaces and uses throughout as well as a structure that can be added to or subtracted from to react to changing uses.

ScenarioImagining a form

The scenarios that we envision are those in inaccessible places or those that lack proper infrastructure for traditional construction.

This scenario employs a one construction element design that utilizes a fold and joint. The resulting form is a continuous cloud structure made of a 3D tesselation of the part. This provides a great variety of spaces and uses throughout as well as a structure that can be added to or subtracted from to react to changing uses.

ConclusionSpeculating on future developments

Documents

Heliobot