ME 8843-Advanced Mechatronics. Project Proposal-Automatic Bike Transmission

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1 ME 8843-Advanced Mechatronics Project Proposal-Automatic Bike Transmission 1/21/09 Razid Ahmad Brandon Borm Todd Sifleet

2 Project Proposal: Our goal for the semester long project is to create and automatic transmission for a common bicycle. This system would accomplish the following tasks: Shift the bicycle smoothly through all available gears Combine the following inputs to determine whether to up-shift or downshift: o Measure torque applied by cyclist o Measure pedaling rate o Measure bike speed Display the gear the bicycle is currently in Allow for manual mode where the controller is disabled and the rider has full control over gear shifting. Provide an effective user interface o Display o Manual Shift Mode And if time permits some further features: Operate as a fully functional odometer: o Measure Current Speed o Average Speed o Distanced traveled. o Etc. Allow for user specific shifting patterns We feel this is a great project idea because it combines the use of sensors to monitor external conditions, software for control/operation, and mechanical components for operation. Further we feel that it accomplishes a useful task, being at the proper gear ratio allows the cyclist to operate at their most efficient pedaling speed and torque. Sub-Systems: Shifting: To allow for shifting we intend to use the standard front and rear derailleur system, these systems contain two independent sprocket sets. This type of system allows for a larger number of gearing combinations and ultimately more allowable gear ratios. Using this system will require two independent actuators to control each derailleur we are considering implementing: Solenoids Stepper-motors DC Motors Servo Motors Worm Gear/Spool Power Screw Sensing Torque: The torque applied to the pedals will be a primary input to the shifting algorithm. We will consider using: Load cell in crank Load cell on pedal Strain Gauge on crank

3 Using accelerometers/speed sensors to measure thrust and deduce torque. We are considering this alternative method because some of the more direct methods may prove difficult to implement. Chain Tensor Sensor Pedaling Rate/Bike Speed: These speeds will also be a primary input to the shifting algorithm. Since these values are proportional to one another it may be redundant to measure them both, but we feel measuring both can be used for odometer function, and deducing the current gear. We are considering using: Variable reluctance sensors Hall effect sensors Photo interrupters Shifting Controller: The controller will integrate all inputs (bike speed, pedal speed, current gear, pedal torque) and output up-shift or down-shift commands. The controller will be designed to allow the rider to pedal at his/hers ideal speed and torque. User Interface: Relevant output data will be displayed visually (LED, LCD). The system will be designed such that user input and configuration will be implemented without a PC. For manual mode switches will enabled the rider to have full control over the shifting, allowing the bike to act as normal. Timeline: We have created a preliminary timeline to try and plan our progress over the entire semester. This helps us plan how we are going to address the design problem, and helps avoid some big problems. Lastly we want to make sure that we address the integration of sub-systems throughout the entire design process. This will help us avoid running into large integration issues this late in the design process.

4 Week 12 4/20/09 Demo/Final Presentation -Wrap up project and create presentation -Final testing to ensure demo goes well -FINAL REPORT [DUE: APRIL 21] Week 10 Week 11 4/6/09 4/13/09 Final Adjustments Trouble shooting -In depth testing of all features under diverse operating conditions -Make necessary changes to optimize performance -Make further improvements to shifting algorithms -Fine tune all aspects of construction Week 7 Week 8 Week 9 3/16/09 3/23/09 3/30/09 Construction Phase Integration -Mount all sub-systems on bike. -Test overall functionality -Complete and test software -Time permitting implement optional objectives -Focus on robust construction and aesthetics. (shock tests, weather test, packaging to optimize performance) -INTERIM REPORT NUMBER 2 [DUE: MARCH 31] Week 5 Week 6 3/2/09 3/9/09 Test Concepts Begin Construction -Begin sub-system and software integration -Build sub-systems as parts begin to arrive -Begin more rigorous sub-system compatibility testing -Integrate and field test sub-systems on bike as they are completed -Begin code writing and algorithm development/implementation -MIDTERM REPORT [DUE: MARCH 10] Week 3 Week 4 2/16/09 2/23/09 Embodiment Design Order Parts -Order necessary components -Design bracketry and integration components -Mock up individual sub-systems, and evaluate performance -Modify plan as needed to minimize potential sub-system incompatibilities. -Finalized big picture design and component selection Week 1 Week 2 2/2/09 2/9/09 Conceptual Design Background Research -Determine torque sensing method -Determine method for interfacing with and actuating derailleur -Determine control interface -Evaluate different hardware components -INTERIM REPORT NUMBER 1[DUE: FEB 12] -Research past similar products -Research available sensors -Find test specimen -Research shifting algorithms

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