Design and fabrication of a high performance human powered hydraulic hybrid vehicle

Efficiency and simplicity are the key aspects that make cycling the most widely used methods of human powered transportation. On the contrary fluid power is a world in which great loads and forces are the masters. The leading question and challenge of this Master’s thesis is whether it is possible to combine this two very different worlds in an effective way. Starting from this question NFPA, in order to engage as many people as possible into this problem, challenges every year college students in the FPVC (Fluid Power Vehicle Challenge) asking them to design a human powered vehicle that uses hy- draulics as the only way of performing the power transmission. Based on this premise, a long and complex work including designing, simulat- ing, building and testing has been carried out during the whole academic year and the purpose of this thesis is to describe the whole process of production of the vehi- cle, from the definition of the problem to the final competition in mid April 2019. The dissertation will be divided in several chapters and will define the context of the project in details, then carry on with the design of the three main systems: the hydraulic system has been used to transfer the power from the rider to the vehicle implementing an innovative hybrid secondary control achieved through the switch- ing of a shut-off valve; all the components have been sized using the combination of two optimization routines embedded in the software Simcenter Amesim. The frame and steering assembly has been designed in order to place all the components and simulated trough FEA analysis to evaluate its expected mechanical behaviour during standard conditions and eventually a digital electronic system has been de- signed and implemented on the vehicle in order to read data from the main vehicle’s systems and provide useful information for the rider. The main core of the electron- ics was a Raspberry Pi and all the software has been written from scratch using the Python language. After that there will be a short illustration of the building phase, carried out autonomously in the Maha lab premises and the description of the final competition where the team scored high marks across the board, prior a structural failure that meant the end of the competition. In the very end, all the expected performances compared to the actual results will be summarized, followed by the description of some future developments that might result interesting.