Urban and Domestic Alternatives to Fossil Fuels: Human Powered Vehicles
Unemployment, increasingly sedentary lifestyles and dependence on fossil fuels are three key issues that threaten the sustainability, progress, and health of Western countries. Spurred on by these issues, this project aims to investigate and produce a prototype of a human powered vehicle for use by individuals and commercial entities in urban areas. Our bodies could never generate enough power to drive our power plants, yet there are still ways that our energy can be put to great use. Interest in cycling as a mode of transport continues to grow, however the mainstream bicycle is not the most efficient design for converting human mechanical energy into motion. The project team will first investigate average human power output and the evolution of human powered vehicles, and then a prototype will be designed and constructed. This prototype must be capable of meeting certain parameters including ease of use, ability to carry a payload efficiently, weather protection and others yet to be determined. A community outreach exhibition will be arranged at the end of the project to provide members of the public, local delivery service businesses, as well as students and staff, with hard data concerning the costs and efficiencies of replacing fossil-fuelled vehicles with human powered vehicles (including the possibility of electric assist).
• Following the mathematical modeling which was performed in Semester 1 of Human Lower Limb Musculature, we have concluded that a recumbent cycle design most effectively harnesses power from the strokes of the most powerful muscles in the body.
• Analysis of different potential loading scenarios has revealed that the most stable design, both laterally and in the case of frontal collision, entails placement of payload spaces on either side of the driver; however this requires both spaces to be equally loaded, and this aspect is still being debated with the possibility that we may rule for a design with the payload placed at the back of the vehicle. Different concept designs are being sketched.
• Material selection for the frame is ongoing, while we investigate the most cost-effective material that is both light and sturdy.
• Once a final design has been selected, a model will be drawn up using CAD tools, and from this we can create the prototype manufacturing blueprints and specifications. We aim to have this finished before the start of semester 2 in January.
• With drawings completed, we will be on track to begin construction of a physical prototype, which may need to be scaled down, to test handling, aerodynamics and tackle visibility issues.
• A scaled down model of this frame will be constructed shortly to test the durability and stability of the frame shape and material
• Further examination of the our mathematical model of the leg muscles, in conjunction with the consideration of the comfort, field of view and safety of the driver led us to elect an elevation of 30° from the horizontal position for the driver’s body with respect to their legs on the recumbent design.
• In order to avoid the inconvenience of making sure both lateral compartments are always equally loaded, we have decided it most appropriate to place the payload bay at the back of the vehicle. This is not to say that the lateral bays couldn’t be included in future designs: these would provide for stable additional storage (if the loads were small or of similar weights) and could be included as an additional feature, but we have concluded that the main storage compartment should be placed at the back of any design.
• Due to ease of manufacturing, availability and lower cost in addition to meeting the required strength and light weight properties, we have selected Aluminium 7010 to constitute the bulk of the frame’s material.
• A full size frame design has been completed, the associated manufacturing drawing can be viewed below.
A brief summary of the topics studied in this project is listed below:
• Safety of the vehicle in an urban environment
• Market and community need in the urban environment
• Vehicle stability and payload placement
• Selection of optimum frame material (best balance of strength, weight and cost)
• Optimal angle of inclination of the driver for maximum power output.
Following examination of the accomplishments to date, and the comparison of the extent of our theoretical models with the original project intent, we have concluded that insufficient design work has been completed in order to proceed to construction for testing: investigation into the power transmission system, aerodynamic improvements, the potential power output of a healthy human body, as well as any potential electronic systems must be completed first.
An extension of the project deadline has been granted, allowing the project to be continued into the 2013/14 academic year. During the allotted time we hope to conclude our investigations and undertake the necessary remaining design work to justify building a vehicle prototype.