🎯Objective

ASME's e-Human Powered Vehicle Challenge (e-HPVC) is an engineering design and innovation competition that gives students the opportunity to network and apply engineering principles through the design, fabrication, and racing of human-powered vehicles.

My purpose of creating ‘Sharkha’ was to build an upgraded and better version of our previous attempts. I have always intended to create a commercially viable product that would buzz around the vehicle and prove its worth by providing comfort, aesthetics, and performance in the Indian market and roads.

Design objectives –

• To ensure the rider's absolute safety while developing cost-effective and environmentally friendly vehicles for the Indian market.

• Design a hybrid vehicle that can handle the bumpy city roads in both traffic and free-riding situations.

• To create a bio-inspired design that strikes a balance between the work of nature and human knowledge to connect us back with our surroundings.

📒 Executive Abstract and Summary

💡Inspiration

Machines have played a vital role in the daily life of human beings. The primary motive behind any innovation has always been to reduce human effort and maximize output. Human Power has been the most reliable and trusted energy source one can use. Taking inspiration from our college’s previous attempt, The LNM Institute of Information Technology was back again in 2022 with a more innovative, durable, fast, and safe human-powered vehicle, SHARKHA, to compete in e- HPVC 2022.

🎨Design and Engineering

My Vehicle is a semi-recumbent, 3-wheel tadpole design with rear-wheel drive, which I chose due to its ability to provide high speed and high stability. AISI 4130 Alloy Steel has been chosen as the frame material as it provides high durability and ease of manufacturing. We figured that the Drive-train should consist of 9 Speed Gearbox. The Fairing of the Vehicle is made entirely of fiberglass, which is cost-efficient and lightweight. My Vehicle’s design is inspired by the body of a shark which makes the vehicle highly aerodynamic.

Initial Design (My initial sketches)

Finalized Design

📐Analysis

The Vehicle was loaded with innovations to improve its safety and performance. The Octagon-shaped RPS, with an added rectangular support for head protection, drastically improves the rider's safety. My team then implemented an extra pulley gear in the drive train, which helps keep the chain tight and prevents it from coming in the rider's way. We have also provided an adjustable handlebar for the comfort of our rider.

🔎 Background and Research Strategy

📝Background Research and Prior Work

As this was our college’s second human-powered vehicle project, I had some experienced and decisive people in my team who guided the rest to channel their energies and skills. So, instead of starting from scratch, we had the previous year’s design, which helped us approach this year's vehicle better; whether it be stability, safety, comfort, maneuverability, or speed, we excelled in almost everything.

'Design of Human Powered Vehicles' by Mark Archibald, 'A systematic approach to human-powered vehicle design with an emphasis on providing guidelines for mentoring students by Alexander S. Whitman, 'Jetrike.com' for ergonomics, and 'Studies on the Dynamics and Stability of Bicycles' by Pradipta Basu-Mandal were among the research materials and books I referred to frequently.

The team faced a significant issue because no facilities were available to test our concepts in real-world scenarios during the pandemic. We tested suitable angles for the seat at home, visualized ourselves riding different iterations of the vehicle, and used online resources and research data to arrive at conclusions about the vehicle's configuration, drive train, seat angles, and many other factors using sheer grit, hard work, and innovative methods. We also solicited feedback from fellow cyclists on what features they wanted to see on a bike. We studied the difficulties they encountered on Indian roads in an urban setting, and we designed our vehicle to drive in that environment easily.

Then I looked at current vehicle layouts to see their advantages and disadvantages and what I might learn from them. All this study assisted us in better-comprehending textbook topics by applying them to real-life situations.

My college participated last year in the HPVC 2021, which was held online; that experience has come in handy immensely in making this vehicle. The objective of this year’s vehicle was not only to reach the standard set by the previous vehicle but also to improve its performance and present a successor in actual terms. The market surveys conducted during the development of the previous year's vehicle helped us save time and money.

⏳Project Timeline

We structured the entire procedure into various stages to guarantee that the vehicle report was finished on time. Each element served as a milestone with its deadline. Starting on the 29th of December with the formation of the team and the initial briefing, we had 39 days to finish the vehicle and its report from the ground up. We made up for our lack of time and expertise through effective management, execution, and synergistic collaboration. From the very first meeting, we organized the entire team into four subgroups: the Design, E-V, Analysis, and Content teams. During the daily meetings, each subgroup worked in tandem, doing analysis and research in their particular areas while keeping each other updated with changes and modifications.

⚙️ Design and Engineering

🧮Evaluation and Development of Design and Concept

Several aspects were crucial for the vehicle to adhere to during the design process, ensuring best-in-class endurance and performance while being the most cost-efficient.

The vehicle travels at a speed of 25km/hr. should stop within 6.0 m. Performance Safety The minimum turning radius of the vehicle should be 8.0 m. · Stability of vehicle at a speed of 5 to 8 km/hr. in a straight line for at least 30 m.

• Breaking Safety Requirement: To ensure effective braking in short distances especially considering the traffic conditions of urban road scenarios.

• Top Load when turned over: 2670 N. Maximum permissible deflection: 5.1 cm when the load is applied at 12 degrees to the vertical side Load: 1330 N Roll Over Protection Maximum permissible deflection: 3.8 cm when the load is applied at shoulder height horizontally. RPS should prevent body contact from the ground if an accident occurs. Absorb sufficient energy in a severe accident to minimize the risk of injury.

• Safety Harness: Use of a 4 or 5-point safety harness attached to the RPS.

• Rider positioning Ergonomics: To design a seat with optimum comfort and connect with the vehicle. Ease of access: Provide sufficient open space around the seat for the rider to easily enter and exit the vehicle.

• Rider positioning Ergonomics: To design a seat with optimum comfort and connect with the vehicle. Ease of access: Provide sufficient open space around the seat for the rider to easily enter and exit the vehicle.

• Minimum turning radius: The team wanted the minimum turning radius to be less than 6.0m keeping the narrow Indian roads in mind.

• Fairing Design: To make a bio-inspired streamlined design to reduce drag and increase aerodynamic efficiency.

• Suspension: To ensure a smooth ride for the rider on Indian roads with uneven terrain and potholes.

• Field of View: On busy roads, considering the presence of other vehicles, the peripheral field of the rider should be kept as open and wide as possible (at least 180 degrees) to ensure that they see approaching vehicles.

• Transmission: To provide a transmission system that operates smoothly and with minimal starting torque and chain slack.

• Budget: A budget constraint of Rs. 50,000 was decided to achieve economic viability.

• EV Specifications: Weight of battery not more than 5 Kg Achieving Range of greater than 90 km.

During our study, the team came across various options, each with its advantages and disadvantages. We utilized decision matrices to select the best solutions that met the established design limitations. Each criterion's matrix had numerous points of comparison, each of which was given a weighting based on its relevance to our design aims.

Vehicle Description

The objective of designing the vehicle is to make a practical, safe, and budget-friendly everyday transport alternative ideal for urban Indian roads. “Sharkha” is a Semi Recumbent, 9-Speed, Rear wheel drive with Indirect Ackermann steering. To add the aerodynamics and increase the efficiency of the vehicle, we made a shark-inspired fairing which fulfilled our needs of getting a lower drag coefficient and maximum rider comfort and space. This overall gives an aesthetically pleasing look to our vehicle. All the wheels are equipped with suspensions to ensure a pleasant riding experience.

Our vehicle has 24-inch rear wheels and 22 inches front wheels. The size of the rear wheel is kept relatively bigger to provide higher stability and more balance while cornering. The two front wheels allow our vehicle to have a smaller turning radius and prevent it from toppling.

Frame: The whole frame has been designed with AISI 4130 alloy steel. The frame is designed for a semi-recumbent RWD vehicle. The final model was selected after taking the inputs from all the team members and deep analysis of the model.

Roll-over protection system: The Design of the RPS was made under the constraints set by the ASME HPVC, keeping the rider's safety at utmost priority and keeping him safe from any injuries that might occur by rollover, collision, ground contact, etc. And extra rectangular support has been provided to keep the rider’s head safe. Circular AISI 4130 steel tubes of diameter were used to build the roll cage.

Suspension:

Transmission: The transmission of our vehicle consists of a 52T crankset connected to a 21 and 15T sprocket. It is then connected to a 9-speed cassette 11 to 36T. Crankset and Speed Cassette are connected via a sprocket, which is responsible for changing the angle of the chain when it reaches the cassette and then redirecting it to the crankset. It also stops the chain from meeting the rider or limiting his motion. Moreover, the 2 co-axial sprockets are free to rotate without hindering each other rotation. The minimum gear ratio of Sharkha is 1.45, and the maximum gear ratio is 4.72.

Fairing: To reduce the drag coefficient and make our vehicle more aerodynamic, in-front partial fairing built with a plain fiber sheet was decided after keeping weight, strength, and cost into consideration. Sharks inspire the fairing of Sharkha because sharks are naturally aerodynamic, and this bio-inspiration fetched us optimal drag coefficients.

PS: And hence the name “Sharkha.” 🙃

Seat: The seat of Sharkha was designed to provide full comfort to the rider with adequate spacing and head arrangement at proper angles. The seat width was decided so the rider had adequate space to manoeuvre his back and shoulder without feeling restricted.

🔥 Innovation and Modernization

Our Idea

Generally, vehicles consist of either Speed Class 1, Class 2, or Class 3 type systems. Still, we have made our vehicle with a mixture of Class 2 and Class 3, which enables the rider to use pedal assist (power of rider added to the power of hub motor) and throttle assist (power of hub Motor) to use the full battery of the vehicle. We developed an e-bike that has both pedal assist and throttle control. We have used a power lever Brake which adds safety to our vehicle. There is a sensor in the brake lever which sends the signal to the controller when we pull the lever, after which the controller cuts the power. When this happens, the vehicle's speed does not increase even if the rider accelerates it. So this prevents accidental acceleration when the rider is trying to apply brakes.

Pedal Assist and Throttle

the Range and Battery capacity of the vehicle, we have assumed that all the 100% power supplied from the battery to the hub motor is usable. After studying different data sets, it is concluded that, on average, 1 Ampere current can move a vehicle to 5km/hr. All these assumptions are made while considering the straight road. The vehicle's motor capacity(P) has been taken as 250W, and Battery nominal voltage(V) is 48 Volts.

Result: The range for pedal assist is 150 -200 km and for the throttle is 80 – 100 km. Battery capacity is 20Ah for both. All these conclusions are made keeping all the roads straight and 100% power supply to the hub motor (in ideal condition). Real values may vary between 60 – 80% of the total range.

Power/Speed Model

The vehicle's maximum speed is calculated to be 10.86 m/s or 39.096 Km/Hr. The vehicle reaches the top speed when the rider pedals with steady 400W combined power. It’s worth mentioning, however, that a cyclist is seldom able to ride this sort of profile, which presupposes a steep rise in power from an initial level to a new, constant level through the usage of EV.

Our Learnings

The section which turns infeasible for us is to ride in a hilly area, achieving bigger distances and making it easy to pedal for a long time because of the higher total weight of the vehicle and the rider, drag force, and friction. As we came to the failures, the first one we encountered was having more battery capacity. Then we should have integrated all components like thumb throttle, pedal assists sensor, optical display, LED light, brake lever, brushless hub Motor and battery management. Then, we made a controller to integrate all the components.

Because of these reasons, the cost of our overall vehicle was increased by 60%.

🔼 Application and Extension of the project

The purpose of creating ‘Sharkha’ was to build an upgraded and better version of our previous attempts. Our intention has always been to create a commercially viable product that would create a buzz around our vehicle and prove its worth by providing comfort, aesthetics, and performance in the Indian market and roads.

Project Application –

• To ensure the rider's absolute safety while developing a cost-effective and environmentally friendly vehicle for the Indian market.

• Design a hybrid vehicle that can handle city roads' ups and downs in traffic and free-riding situations.

• To create a bio-inspired design that strikes a balance between the work of nature and human knowledge to connect us back with our surroundings.

• Further scope of improvement a) We can improve our vehicle by adding contemporary technologies like b) proximity sensors c) regenerative breaking d) GPS

Machine Learning and Automation

As we know, in the modern world, every device is getting automated to a degree where it can be easier to use without causing any hassles. Technologies like Machine Learning, Artificial Intelligence, the Internet of Things, etc., are being developed for the same. So to future proof our project, we can use systems like:

• Object Detection System: like Tesla, we can develop a machine learning algorithm that would be able to detect objects near it, and this data can be used to drive the brakes in emergencies. To protect the driver and to keep the damage cost minimum.

• Automated Head Lamp: this system already exists in the market where the headlamps turn on when the sensor can’t detect light around the vehicle, which activates the headlamps, cabin light, and LCD screen.

• Smart Pedal Assist System: gyroscopic sensors can be used on the vehicle to determine the inclination at which the vehicle is being driven. In the case of an uphill driving condition, the pedal assist will be automatically engaged to help the rider. Similarly, in the case of Downhill conditions, the extra force can be used to charge the battery, which will also make the vehicle travel at a more controllable speed reducing the chances of a crash.

🥸 Conclusion

During the design of Sharkha, all the Product Design Specification (PDS) criteria and all ASME HPVC Asia Pacific constraints were taken care of and produced the best possible results. After making the vital amendments to the design, Sharkha successfully passed all the inspections and tests, such as strength, environmental impacts, cost, etc. This also meets our expectations of making our vehicle more reliable, stable, manufacturable, comfortable, and cost-efficient than the last attempt. As a team, we have developed a vehicle that incorporates all the innovative ideas and concepts in the human-powered vehicle.

🚀 The Way Forward

We think our project has the caliber to be a mass-produced product that can affect people's daily lives by providing a more comfortable and cleaner source of transport. With necessary improvements and design changes, we can pitch our design to the government as pollution is one of the country's main concerns. With suitable manufacture, our vehicle can be sold in metropolitan cities. Government can also grant subsidies for buying this vehicle as they do with EVs and other hybrid vehicles.