ECO-PRT AUTONOMOUS ELECTRIC VEHICLE PROJECT
INTRODUCTION
Eco-PRT is an alternative mode of public transportation in the future. The system consists of an autonomous electric pod that will travel on an elevated rampway. The motivation behind this idea is to minimize wastage of public spaces which is used up for parking of vehicles. While a person uses vehicles only for commute, the amount of investment to support such infrastructure which includes building more roads and parking spaces is massive. Moreover, these parking spaces are under-utilized for the majority of the day. The Eco-PRT project aims to provide a clean and affordable solution to solve this problem. The team members of the project have fabricated a Gen 2.5 version of the vehicle. Meanwhile, design and development is being done for Gen 2.6.
Major highlights are listed below:
1. Designed a test fixture and wrote code for data collection and analysis from onboard hall sensors.
2. Reduced 15% in kerb weight by using thermoforming to create an external ABS-based shell for the pod.
3. Redesigned the electromechanical steering actuator mechanism for robust operation and to mitigate potential wear issues.
4. Optimized suspension design using a genetic algorithm. Reduced the natural frequency of pod to 1.9 Hz.
5. Conducted DFMEA of A-arm subassembly. Improved design for performance under impact loading conditions.
6. Modified upright design for weight reduction by 20% and reduction of CNC machining time by 30%.
7. Created CAD models of a casing for housing PCB boards and printed them using a 3D printer.
8. Created a dynamic model of Eco-PRT vehicle in Simulink.
SUSPENSION OPTIMIZATION USING GENETIC ALGORITHM
A genetic algorithm is a powerful tool and is an integral part of various engineering design optimization
procedures. The genetic algorithm is based on the law of natural selection. The fitness parameters of a
parent value are determined by the individual. The genetic algorithm progresses in various stages.
Various details related to this method are mentioned below:
A-ARM REDESIGN
A major issue with the existing A-arms was their failure when hitting a curb. I proceeded with the redesign process by estimating the reaction forces at wheels in such an event. This was done by creating a force triangle in Solidworks. This was followed by altering the existing design to reduce the areas of stress concentration. Additionally, the pipe diameter was increased and gussets were added to reinforce the A-arm.
The new design is shown in the gallery below:
ENCLOSURE DESIGN AND 3D-PRINTING
A casing was needed to house the PCB boards on the vehicle underbody. I proceeded by taking measurements of the PCB board. This was followed by creating a CAD model of the same. Finally, this model was sent to a 3D printer and was printed using ABS material. There were some modifications done after the first print for better fitting of PCB board in the case.
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UPRIGHT DESIGN
Issues with previous design
The previous upright design had extraneous material which resulted in an increase in weight and a reduction in overall efficiency of the vehicle. The extra material was getting used up in empty mounting points. While this approach did make the design simplistic, it increased the weight of the front upright unnecessarily.
Changes Implemented:
The new design resulted in a weight reduction of 152.85 grams. The previous weight of upright was 884.23 grams. After Redesign it was 731.38 grams. The new upright design is safe under application of loads. There is plastic deformation in the structure when loads are applied. The design was also simplified for the ease of machinability.
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