Imagine a world where instead of working yourself and getting exhausted, you can have your training bicycle work FOR you.
Introducing the world's first autonomous, human replacement exercise bike. You can chill at the beach, having you favorite drink and not feel bad about it. You even know how many calories you could have lost.
Step 1: Physical Analysis
The first challenge of having an autonomous bike, is
Among many ways to do that, the most outrageous one has got to be using a FREAKING HUGE MECHANICAL GYRO (AKA F.H.M.G).
After calculations of bike inertia during movement, we came to the conclusion that that FHMG has to be a circular Iron Cast mass of 7 kg, with a 220mm diameter.
Step 2: F.H.M.G Design
That mass will have to spin at thoroughly 2000 RPM and will achieve enough angular momentum to balance the bike around its axis and allow for a smooth and easy drive around the park.
The final design utilizes 2 12V CIM motors with a gear ratio of 1:3 towards the F.H.M.G main shaft.
In addition, the whole F.H.M.G has to be on a spinning turret at the bike's centre of mass in order to make balance easier. We easily replaced the bike seat with the F.H.M.G turret, and control it using a Window Motor and 1:1 Chaining. The motor was chosen for its high power transmission and the positives of having a worm gear on such an heavy block (~16 KG).
Step 3: Adding Drive and Steer Motors
In order to move forward with as light a mechanism as possible, we neglected designing an on shaft gearbox like a regular modern electrical bicycle uses, and designed a unique friction based wheel, that contacts the rear wheel with high pressure, making it be the drive wheel while allowing reverse and forward drive.
The steering control is achieved with a planetary gearbox, placed on the forward wheel shaft with a 1:20 gear ratio, allowing smooth, slow and predictable steering of the wheel. This is important if you want your bike to avoid collisions, and also adds to the balance of the whole project.
Step 4: Developing the PPLCC (Potential Precise Lost Calorie Calculation)
The PPLCC (Potential Precise Lost Calorie Calculation) is very important for the user, who must know how many calories he hasn't lost during the last training session the bicycle did for him.
In order to calculate the exact amount of lost energy, we measure the total sum of Angular Momentum provided and add it the lost energy from the systems battery. The sum of the 2 is a direct measurement of lost energy.
In addition the user can reduce the number of lost calories as a result of drinking Araq or other beverages during the hard and tiring training.
The PPLCC is a real time, always displayed system with an easy to use customizable interface .
Step 5: Control System
For the entire project we are using an NI Compact Rio
controller. It allows us to maneuver the gyro turret with high precision and low response times. The Turret control is a closed PID loop, with the input of a regular analog gyro sensor and the window motor controlling the exact angle of the turret at any time. The mass is is spinning at a constant speed, making the PID loop easier.
The drive and steer motors are controlled via a wireless Joystick and at a later phase will be autonomously controlled in a closed loop with an on board webcam.