Course Information
Summary
This is a project based class offered in the Spring quarter involving design and prototyping of electric vehicles. Students learn the fundamentals of vehicle design in class and apply the knowledge as they form teams and work on projects involving concept, specifications, structure, systems, integration, assembly, testing, etc.
The class meets once a week to learn about fundamentals of vehicle design and coordinate sub-tasks. The teams of 3-5 work on their projects independently.
Contact and Facts
| Instructors: | C. Gerdes, S. Beiker, TA: Ben Stabler |
| Time: | Tuesday, 3:15-4:30pm |
| Location: | Volkswagen Automotive Innovation Lab, VAIL (link) |
| Prerequisites: | Basic knowledge in vehicle design / dynamics, energy systems |
| Grading: | Letter |
| Units: | 3 |
| Proposals | Project proposal has to be submitted to Sven Beiker by March 29 in order to be considered for the class. see further details here, download form here |
| Lab Access: | http://vail.stanford.edu |
Schedule
| Week | Date | Topic |
| 1 | Tue, 4/2 | Instructions Student Proposals |
| 2 | Tue, 4/9 | Electric Components Lecture |
| 2 | lab session, date tbd | Students record vehicle data on go-kart (part 1 of modeling lab) |
| 3 | Tue, 4/16 | Vehicle Dynamics Lecture |
| 3 | lab session, date tbd | Students build model of go-kart, fit to vehicle data from previous lab (part 2 of modeling lab) |
| 4 | Tue, 4/23 | Production Electric Vehicles Lecture Administrative Matters of the Course |
| 5 | Tue, 4/30 | Check-In, class comes together to discuss project progress |
| 6 | Tue, 5/7 | Check-In, class comes together to discuss project progress |
| 7 | Tue, 5/14 | Check-In, class comes together to discuss project progress |
| 8 | Tue, 5/21 | Check-In, class comes together to discuss project progress |
| 9 | Tue, 5/28 | Check-In, class comes together to discuss project progress |
| 10 | Tue, 6/4 | Demo Day, presentation of final concepts (date tbc) |
Material for Lab Sessions
To prepare for the lab sessions, please download and take a look at the following files:Course Summary 2012
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During a ten week period beginning April 3rd 2012 and culminating in a demonstration on June 7th 2012, a class of twelve students produced four electrified vehicle prototypes and two EV specific design proposals. This project based class explored the design constraints and opportunities presented by the electric vehicle drivetrain and classroom based lectures were supplemented with student led construction of functional light electric vehicles.
Electric "Pocket Rocket"
A team of three students recognized that the "Pocket Rocket", a small and inexpensive toy motorcycle platform, would be an interesting electrification challenge, and that an electric Pocket Rocket would enjoy many advantages over its petrol cousins. The team obtained an old bike with a burnt out engine and rebuilt the vehicle around a 19hp peak brushed electric motor. In order to fit the 1.5kWh battery pack in the tiny vehicle body the team made frame modifications before repainting and reassembling the vehicle with a quality of finish that makes it almost indistinguishable from an off-the-shelf pocket motorcycle.
While the "Pocket Rocket" may have unassuming looks that certainly doesn't mean it is lacking in performance; with a low-end torque characteristic to an electric motor the small bike easily lifts the front wheel under acceleration despite the 80lbs of battery located close to the front axle. This thrill factor is enhanced by the deceptive silence of the electric motor. A complete product, the Pocket Rocket electric motorcycle epitomizes the small electric vehicle.
Electric Skateboard and BMS
Two students designed a low cost monitoring system for lithium cells and built a lightweight electric skateboard around this system. The team recognized the distinct advantages offered by lithium cells over conventional chemistries and chose to investigate how inexpensively they could construct a compelling lithium based electric skateboard. The result was a skateboard with enough power to propel the rider at up to 20mph and up reasonable inclines but light enough that it could be used as a regular skateboard and without significantly impacting the handling. The team extended the project by designing a PIC based wireless remote throttle.
Electric Go-Kart
A team of three students designed an electric go-kart with emphasis on performance and flexibility. The team specified motor, battery and motor controller components to maximize performance by achieving a high power-to-weight ratio and making the weight-capacity tradeoff wisely based on foreseen operating conditions. Design of the kart also emphasized flexibility as the team intend the vehicle to serve as a platform for future student projects related to EV design, instrumentation, analysis and innovation.
As with any small electric vehicle, compromises must be made between peak acceleration, peak speed and maximum run time. The team spent time optimizing this tradeoff based on data gathered from conventional go-karts on a range of racing tracks before any components were specified, and the result is a vehicle with a well-balanced drivetrain and the sort of throttle response you can only get from an electric motor.
Electric Scooter
Two students wanted to find out how readily you could electrify a ride on scooter using commercially available components. The students purchased a standard push scooter and modified the platform to accomodate their electric powertrain. Next the students designed a simple speed controller using off-the-shelf parts and integrated the system on the frame.
Given more time, the students would have extended the project by designing a wireless control system based around the Arduino microcontroller to control the speed of the vehicle and record performance characteristics.
High Efficiency Solar Car Motor
A student with experience working on the Stanford Solar Car Project (link) set out to design a high-efficiency solar-electric vehicle motor. The student chose to employ a coreless axial flux permenant magnet three-phase brushless design with particular innovations for a solar car racing application such as high efficiency bearings and a single-sided mount.
The project emphasised design-for-manufacturability from the outset and the final report details and quantifies all design tradeoffs and indicates avenues for further research. While the final design could not be manufactured within the deadlines of the course, there is a strong chance that the work done is incorporated into an electric motor used in the future on the Stanford Solar Car.
Low-Loss Light Electric Vehicle Suspension
A student currently involved with the Stanford Solar Car Project chose to investigate the trade-offs involved in the design of a light electric vehicle suspension with a particular focus on maximizing vehicle efficiency and controllability. The student approached the design from first principals, identifying the effects of different wheel displacements and rotations, constructing a model and then designing a geometry which satisfied the constraints of the model. The student chose to design parametrically so the design could be generalized to a variety of light electric vehicle configurations.
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For further information please contact Sven Beiker (beiker@stanford.edu)
Course Summary 2011
On June 2, 2011 students from the class "Electric Vehicle Design", instructed by Prof. Chris Gerdes and Sven Beiker, presented the prototypes they had worked on over the spring quarter. This project based class focused on the design and prototyping of electric vehicles. Students discussed the fundamentals of vehicle design in class and applied the knowledge as they formed teams and worked on projects involving concept, specifications, structure, systems, integration, assembly, testing, etc.
The idea of the class was to generate interest as well as excitement around electric vehicles and give students the chance to realize their ideas. At the end of the quarter the 4 teams of 2-4 students each presented their prototypes:
Commuter Electric Bikes
The group asked the question how an electrified bicycle can best support commuters in terms of efficiency and cost. The students aimed at a solution for people who are discouraged from public transit by the distance between the transit station and their home/work. They proposed a bike that commuters can take to the train station or bus stop, i.e. an e-bike with a relatively low range (to eliminate more expensive solutions that most e-bikes provide), while covering the realistic needs of commuters. The team also proposed that the concept would need to have improved aesthetics, i.e. a bike that a self respecting adult would be seen on.
To address those requirements, the students followed two paths: One bicycle with an off-the-shelf hub-motor kit for bicycles to experiment with the electric drive train, and - equally important - with regenerative braking that the team pursued to improve overall efficiency of the concept. The other bicycle was equipped with a self-designed powertrain including a battery management system to maximize the performance of the Li-Ion batteries. The team added to this bicycle a GPS based data-logging system to acquire data from actual use-cases and to optimize the concept based on the individual needs.
Electric Go-Kart
The group had the vision to create an electric vehicle with truly exciting performance characteristics and therefore decided to electrify a racing kart. The students acquired a gasoline powered go-kart and converted it into an electric version with a motor of close to 10HP. With the challenge to integrate all necessary electric / electronics and mechanical modifications into the existing layout of the vehicle, some basic vehicle dynamics problems surfaced as well. For instance with all the batteries in the rear, the resulting weight distribution compromised the steering capabilities.
Therefore the students learned very significant aspects in converting vehicles to electric as well as the overall concept and how the dynamics of a vehicle can get negatively affected when trying to optimize just one characteristic. However, the students accomplished their goal of a truly exciting vehicle as the kart was revealing acceleration characteristics that clearly beat those of its gasoline powered former self while still offering a top speed of about 40mph. Some team members even showed great interest in continuing to work on electric vehicles for competitions and potentially form a student racing team.
Lepton - Three-Wheeled Electric Vehicle
The group was taking an initial version of an electric light-weight vehicle to optimize the concept regarding the body structure and suspension. With the initial concept only offering very basic components in that regard, the goal was to design an extremely light, yet strong shell as a body and a suspension with the same characteristics.
The students prototyped a monocoque body out of carbon fiber sandwich sheets which accommodates the driver, the battery, and most of the electrical / mechanical components. While the suspension follows still a relatively traditional design with double wishbones, the steering of the front wheels is operated by two pull / push levers, one on each side of the driver. The rear wheel is driven by a hub motor that accelerated the concept well beyond 30mph.
Solar Car High Efficiency Motor and Electric Powertrain Testrig
The group worked on components that would benefit the solar car, which will be raced in Australia in October 2011. As the vehicle is being built completely from the ground up, new motors are also being considered as opposed to using the ones from the predecessor. In order to better understand the electromagnetic and mechanic-dynamic properties of an electric motor, the students decided to build a motor completely from scratch with machining the stator / rotor, winding the coils, and prototyping the controls themselves. While the electric design was relatively straight-forward, the dynamic balancing of the rotor became a challenge along with the precision assembly of the entire machine.
In order to prove the performance of the electric motor and also to test other electric drive components, the students prototyped an electric powertrain testrig to measure torque / speed characteristics. The equipment became invaluable for the design of the drive motor for the solar car and was also used to test the motor for the electric kart (see above).