International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN:2395-0072
Conceptual Design and Construction of an Electric Unicycle
Sanapathi Srikeerthana1*, Sharanya Giri2, Yash Ingle3, Dr. Hrushikesh B. Kulkarni4
1,2,3Students, School of Mechatronics Engineering, Symbiosis Skills and Professional University, Maharashtra412101, India
4Faculty, School of Mechatronics Engineering, Symbiosis Skills and Professional University, Maharashtra - 412101, India ***
Abstract - This paper explores the design and environmental sustainability of electric unicycles (EUCs) as a viable alternative to conventional fuel-based modes of transportation. By analyzing the carbon emissions associated with such vehicles and substituting a portion of daily commutes with EUCs can lead to substantial reductions in greenhouse gas emissions. The study underscoresthepotentialofelectricunicyclestocontribute to cleaner urban environments and promote sustainable transportation practices. Additionally, the conceptual design as well as constructional features of an EUC are discussed.
Key Words: EUC (Electric Unicycle), ESC (Electronic Speed Controller), IMU (Inertial Measurement Unit), GHG(GreenHouseGas).
1.INTRODUCTION
Electric unicycles are a type of self-balancing personal transportation device that has been gaining popularity because of the advancementsin electric mobility.Asingle wheel housed within a compact frame is powered by an electric motor and controlled by gyroscopic stabilization technology. The rider balances the device by leaning forward and backward, with the automatic adjustment of the device's speed and direction in response to retaining the balance. Electric unicycles, initially viewed as a novelty, have grown into a convenient mode of transportation for urban commuters, fitness enthusiasts, andrecreationalusers.
The main components of a portable EUC comprise a brushless DC motor, rechargeable lithium-ion battery, gyroscopicsensors,accelerometers,andamicrocontroller forprocessinginputstoultimatelyregulatebalance.These modern unicycles are available for commuting on various types of terrains and are fitted with all-terrain tires, enhanced suspension systems, and weatherproofing. A range of users is catered to through these devices, with speedsfrom20km/htoover50km/handsomehaving a rangeofmorethan100km.
1.1 Present Design of Electric Unicycles
Modern electric unicycles are designed with the latest engineering and ergonomic considerations to ensure performance, safety, and comfort for the rider. Common designsinclude:
Compact Body: The body is sleek and lightweight, designed for portability. Materials such as polycarbonate and aluminum alloys are used to reduce weight while ensuringdurability.
Gyroscopic Stabilization: Gyroscopic sensors and accelerometers work in tandem to adjust balance dynamically, enabling smooth rides even on uneven surfaces.
Motor and Battery: High-performance brushless motors providetorqueandspeed,whilelithium-ionbatteriesoffer extendedrangeandshorterchargingtimes.
Control Mechanisms:Riders usefootpadsforinput, tilting them forward or backward to accelerate or decelerate. Advanced models also feature smartphone apps for customizationanddiagnostics.
Safety Features: Anti-slip footpads, LED lighting, and integratedbrakingsystemsenhanceridersafety.
For example, models such as the InMotion V12 and KingSong S22 Pro represent the cutting edge of EUC technology, offering regenerative braking and app-based customization.
Following are some of the advantages of Electric Unicycles:
1. Eco-friendly: Electric, zero-emission means a cleaner urbantransportationmodel.
2.Compactandportable:Smallsize,lightweight,makingit easytocarryandstoreintightspaces,eveninurbanareas.
3. Cost-effective: EUCs require relatively lower operating andmaintenancecostscomparedtotraditionalvehicles.
4. Energy Efficiency: Electric unicycles consume minimal energy, hence an energy-efficient alternative for short to mediumdistancetravel.
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN:2395-0072
5. Versatile Use: Advanced models can handle various terrains,makingthemsuitableforbothurbanandoff-road riding.
along with advantages there are some disadvantages like steep learning curve, limited safety features and cost of highendmodels.
2. LITERATURE REVIEW
Itwasfoundoutthat Chithambaret.al.,[1]presentedthe effect of polypropylene fibers in Geopolymer Concrete; this study presents the importance of material selection andcompositioninconstructionprojects.Bhatiaet.al.,[2] discussedergonomic evaluationandcustomizeddesign of a kitchen, focusing on the importance of user-centered design to enhance work efficiency. Reddy et. al., [3] presented energy efficiency measures for hospital buildings, which is a good example of how sustainable construction practices can reduce energy consumption. Janani et. al., [4] presented a project on voice-controlled cameradesignusingRaspberryPi,whichisanexample of technology integration in design projects. LuwembaMugumya et. al., [5] discussed how linked building data supports alignment of augmented reality withsustainableconstructionandrevealsgreatpotentials by way of technology involved for improving the construction process. Sharma suggested a robust state feedback controller for a photovoltaic inverter system, which raises the significance of control systems in optimizingenergymanagement.Sreeet.al.,[6]carriedout seismic analysis of flat slabs making use of the software ETABS. The same article highlighted how structural analysis is integral to the overall safety of any building. CAD-basedanalysisfeasibilityofdesigninganamphibious vehicle with Majumder et al., [1]. The Design and Estimation of High-rise Residential Apartments was done by using Staad by Krithi et. al, [7]. This involves prosoftware, an approach that illustrates how technology would ease the entire process of construction. In summary, the review based on these documents emphasizes that the selection of material, the need for a user-centered approach in design, energy efficiency, and the application of technology alongside the structural analysis is crucial to both the designing and construction stages[8,9,10]
3.
WORKING PRINCIPLE
AnElectricUnicycle(EUC)operatesontheprincipleofan inverted pendulum [11], where the bob is located above thepivot point,makingitinherentlyunstable. Continuous adjustmentsbyanactuatorormotorarerequiredtoapply forcesthatkeepthependulumuprightandstable.
Fig -1:InvertedPendulum
Here,
=MomentofInertiaofWheel
=MassofWheel
=MomentofInertiaofbody(pendulum)aboutitspivot point
=Massofbody
L = Length from the pivot to the center of mass of the pendulumbody
�� = Angular displacement or tilt angle of the pendulum bodyfromtheverticalaxis
��=Torqueappliedtothesystem
4. CONCEPTUAL DESIGN
4.1 Chassi
Fig -2:ChassiofEUC
The Chassi of the electric Unicycle was designed in SolidWorks (units used - MMGS), keeping in mind the spaceneededforvariouselectroniccomponents.Alimited amount of space has been allocated on both sides of the chassis, where the electronics will be mounted in the recessedsections.
5. CONSTRUCTIONAL FEATURES
The entire electronic hardware is bifurcated into two boards,namelyPowerboardandControlboard.
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN:2395-0072
5.1 Power board
Itincludesthefollowing:
● ESC or Motor driver circuit: It serves as the system's brain, controlling the motor's speed based on signals from the throttle controller. Its main function is to regulate the interaction between the battery and the electric motor. A readymade ESC was not available in the market; therefore,acustomESCwasdeveloped.
● Battery: A minimum current of 8.33A is necessary for the system to operate without lag. Considering the motor's power requirement of 600W,a72Vbatterypackcapableofdeliveringat least 8.33A continuously was selected. The INR18650P42A Lithium-ion cell by Molicel was chosentomeetthisrequirement.
● Power distribution & Voltage stepdown: Itisachievedinthefollowingmannera)12V-forgatedriverIRFB21844S b) 5V - for Bluetooth module HC05, STM microcontroller,hallsensorandOPAMP c)3.3V–forIMU
Thepowerboardfurtherinvolvesthefollowing:-
● Power electronics: includes the MOSFET IRFB3207TypeTO220AB
● Gate driver IC: theIR2184SHalfBridgeDriverIC, whichiswellcompatiblewiththeMOSFETabove.
5.2 Control board
Itincludesthefollowing:
● Microcontroller unit: STM32BluePill
● Inertial measurement unit circuit accurately detects position, motion, and acceleration, providing essential data for maintaining balance and ensuring smooth operation. The Invensense MPU6000isutilizedforthispurpose.
● BLDC Motor
Thecontrolboardfurtherincludesthefollowing:-
● IMU circuit: collects orientation and acceleration dataandsendsittothemicrocontroller
● Gate driver circuit: involves 3 gate drivers responsiblefor the switchingof3 MOSFETS.Gate driver IRFB21844S has been used for this purpose.
● Hall sensor circuit: involves 3 hall sensors whose signals are amplified using an OPAMP circuit. The LM324 hall sensor has been used for thispurpose.
6. MARKET RESEARCH
A Google form survey with 20 respondents revealed an average interest of 8/10 in owning an EV, with 40%
already owning 4-wheeler EVs and 60% owning 2wheelers. Daily travel averaged 24 km, with monthly fuel costs around ₹3,000. Performance was identified as the most important feature in an electric unicycle, with an expected starting price of ₹86,000. Respondents' average age was 33 (range: 21–50, including three aged 60+), and 70%ofthoseaged18–35expressedinterestinowningan EUC.
6.1 Comparison to owning a common petrol scooter
A cost comparison of owning a petrol scooter (Honda Dio 2016 model) [22] and an electric unicycle has been made to have better understanding as to how owning such a vehicleisnotonlycostefficientbutalsocontributestothe environmentinthelongrun.
Table -1: Comparisonofcost
Parameter Petrol Scooter [2] EUC
Cost of Ownership ₹71,323/EMI@9.7% = ₹6254/month ₹100,000/EMI@9.7% =₹8778/month
Running Costs (30Km/day)
Yearly running costs
₹1918.18/month (@₹106.06/L) (@Mileage - 48 km/L) ₹54.0288/month (Battery capacity = 0.840kWh)
Fuel/Energy + Maintenance ₹29,027 ₹1,648
6.1.1 Savings
After making an estimation for the cost of ownership, a detailed analysis of the generated carbon footprint for boththevehicleshasbeenmade.
Table -2: Savings
YearlySavings ₹28,400
ROIpositive 3.5years
7.
CALCULATIONS FOR CARBON FOOTPRINT
This section presents a comparative analysis of carbon emissions before and after incorporating an electric unicycle (EUC) into daily commutes. It evaluates the carbon footprint of three commonly used modes of transport in India cars, scooters, and auto-rickshaws (public transport) against the EUC. The calculations highlight the emissions generated by each mode and illustrate how substituting a portion of daily travel with
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN:2395-0072
EUC can significantly reduce yearly carbon emissions, emphasizing its potential to drive meaningful environmentalbenefits.
7.1 Upstream and Downstream Emissions
[13] Upstream emissions refer to greenhouse gas emissionsgeneratedduringtheearlystagesofaproduct’s lifecycle. These include emissions from the extraction, production, and transportation of raw materials or fuels before they reach the end user or are combusted. For example, in the case of fossil fuels, upstream emissions coverprocessessuchasdrilling,refining,andtransporting thefueltothepointofuse
Downstream emissions are greenhouse gases released after a product is sold or leaves the control of the producer. They occur during the use, disposal, or further distributionoftheproduct, suchasburningfuelsorusing vehicles.
Understandingupstreamemissionshelpsusseethebigger pictureofhowenergyand materialscontributetoclimate change.
7.2 emissions for a 110cc petrol scooter of mileage 48kmpl in g/km [2]. emission factor of petrol (gasoline) [14] = 2.27kg /L
emissions (upstream + downstream) [15]= 3.14kg /L
Withreferenceto[16] emission per km =
(1)
=65.41g/km
Distancetravelledperyear=960km
Yearly emissions = emissions per km * Distance travelled per year (2)
=65.41g/km*960km
=62.79kg/yr
7.3 emissions for a diesel car of mileage 18kmpl in g/km [17]. emissionfactorofdiesel[4]=2.64kg /L emissions (upstream + downstream) [18] = 3.2kg /L
ThelifecycleGHG(GreenHouseGas)emissionsofaverage gasoline and diesel cars are quite similar and relatively high [19], meaning the choice of fuel type does not significantlyaffectthecalculationbelow
Now,withreferenceto[6]: emissionperkm=
=177.77g/km
Distancetravelledperyear=7300km
Yearly emissions = emissions per km * Distance travelledperyear
=177.77/km*7300km =1297.72kg/yr
Similarly,foranAutorickshaw(Publictransport):
7.4 emissions for a petrol auto of mileage 25kmpl in g/km [20]. emissionperkm= =125.6g/km
Distancetravelledperyear=500km
Yearly emissions=125.6g/km*500km=62.8kg/yr
7.5 emissions for EUC of range 50km with a battery capacity of 1.2 kWh in g/km.
Energyperkm= = =0.024kWh/km
Yearly energy use (kWh) = Energy consumption per km (kWh/km)*Distancetravelledperyear(km) =0.024*1642.5 =39.42kWhperyear
India's electricity grid emits approximately 713 gCO₂ per kWh,primarilyduetocoaldependency[11][6]
YearlyCO₂emissions=39.42kWh*713gCO₂/kWh =28.12kgCO₂/year
emissionperkm= =17.12g/km
Emissionsfrombatteryproduction[12]=73kg/kWh
Totalemissionsfromproduction =1.2kWh×73kgCO₂/kWh=87.6kgCO₂.
Assuming the EUC battery has a lifetime range of 50,000 km(typicalforlithium-ionbatteries):
Emissionperkm
= = =1.75gCO₂/km[3]
Totalemissionsperkm=1.75+17.12=18.8g/km
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
Volume: 12 Issue: 05 | May 2025 www.irjet.net p-ISSN:2395-0072
The data calculated above can be represented in a table formasshownbelow:
Table -3: CarbonEmissions
Table -4: CarbonSavings
Although EUCs offer advantages like portability, last mile connectivity, environmental friendliness as well as inter compatibility with public transport, integrating them into our daily routines can be challenging as they are a relatively new mode of transport. This is why a method has been created to demonstrate how small adjustments to our commuting habits can be both simple and environmentallyfriendly.
In the table above, ‘X’ is the total distance that can be travelled on EUC by limiting our yearly commutes by Car, scooterandpublictransport(Autorickshaw).
Forinstance,limitingcaruseto12.5%(i.e.usingEUCfor1 in 8 car rides from total car rides per year), Scooter and public transport to 50% of the yearly commute allows spaceforEUCstobecomeaviablealternative.
so,12.5%of7300km(forcar)=912.5km
50%of960km(forScooter)=480km
50%of500km(forAutorickshaw)=250km
This distance calculated above can thus be covered by EUC.
So,912.5+480+250=1642.5km
Therefore,X=1642.5km
Now let us calculate the total carbon savings this method canbringby:
Distance travelled per year[Km]
Carbon emitted per year[Kg]
Carbon emitted by EUC for the same
carbon saved/yr when EUC is used[Kg]
Thus,TotalCarbonemissionssavedperyearwhenEUCis usedis=145.06+22.37+22.38 = 189.80KgCO₂
Therefore,thecarbonfootprintsavingsareshownbelow: Regular carbon footprint per year [Kg] = 1297.72 + 62.79 +62.8=1423.32KgCO₂
Table -5: TotalCarbonSavings
Parameter
Regular carbon footprint per year[Kg] 1423.311
carbon footprint after reduction in car, scooter and publictransportcommutes 189.807
EUC Carbon footprint per year 28.12
carbon consumption after switchingtoEUC(net) 1233.504
Carbon savings per year in [Kg] 189.807
Carbon Emission Savings in percentage[%] 13.336
Thus, after limiting our commutes through car, scooter andpublictransport,atotalof189.80kgCO₂canbesaved from getting released into our environment, which is 13.33%lesserCO₂
International Research Journal of Engineering and Technology (IRJET) e-ISSN:2395-0056
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8. APPLICATIONS
● UrbanCommuting:Efficientmodeoftransportfor daily commute which allows riders to maneuver through traffic and crowded places, reducing traveltime.
● Last-Mile Connectivity: EUCs can bridge the gap between public transportation hubs and final destinations. Riders can easily carry them onto buses or trains, making them ideal for last-mile solutions.
● RecreationalUse:canbeusedforexploringparks, campuses, and urban landscapes, providing a fun andengagingwaytotravelshortdistances.
● Professional Settings: helps in offering enhanced Mobility in Workplaces with large facilities like warehouses, factories, or corporate campuses. EUCs can improve mobility for employees. They allowstafftomovequicklyacrossextensiveareas, enhancingproductivityandresponsetimes.
9. CONCLUSION
In conclusion, this research highlights the potential of electric unicycles (EUCs) as a sustainable alternative to traditional transportation methods like fuel based autorickshaws, cars, and scooters. By substituting even a portion of these commutes with EUCs, a significant reduction in greenhouse gas emissions can be achieved. Embracing EUCs in daily commutes is a proactive step toward a greener future, demonstrating that sustainable transportation is not only necessary but also achievable throughinnovativetechnologies.
10. FUTURE SCOPE
Thefuturescopeofelectricunicyclesencompassesseveral promising developments and research opportunities. Advancements in battery technology are expected to enhance performance, reducing charging times, and
extendingbatterylife.Theincorporationofsmartfeatures, suchasGPStrackingandreal-timemonitoring,canfurther improve user experience and safety. As urbanization accelerates, the demand for EUCs is likely to grow, with further and better studies on consumer behaviour and preferences.
Additionally, the development of dedicated infrastructure suchasbikelanesandchargingstations,willbecrucialfor widespread adoption. Regulatory frameworks will evolve toensuresafetystandardsalongwithdiverseapplications insectorslikedeliveryandtourism.Ongoingsustainability assessments will be vital to evaluate the environmental impact of EUCs throughout their lifecycle. Overall, these areas represent significant opportunities for innovation and research in promoting EUCs as a sustainable transportationsolution.
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