This project was undertaken in a team of four for Mecheng 236: Design and Manufacture 2, and received a grade of A+.
The goal of this project was to produce a preliminary design for a tilting three-wheeled LE-1 class vehicle, creating engineering drawings and a BOM for manufacture, and presenting the design to stakeholders.
I was in charge of the tilting system, which used a hydraulic motor to tilt the passenger cabin around corners. I also created a small 3D printed scale model for use in the presentation, which featured an internal battery and set of LED lights for effect.
The tilting system used a closed-loop hydraulic circuit, which allowed for precise analog motion
control, in contrast with the simple binary on/off control of a solenoid valve in an open-loop circuit. This was to ensure a smooth and responsive ride for maximum passenger comfort.
The hydraulics used a commonly available hobbyist gear pump, the CUT-YDL55, featuring a 5055 brushless motor with a rated flow rate and pressure 1000ml/min at 10 MPa (1450 PSI). An ODrive S1 ESC was used to provide smooth and precise control of the motor.
The hydraulic motor used was a Parker LTR-252 Double Rack and Pinion hydraulic actuator. This was selected for its low leakage and corresponding high position-hold effectiveness, as well as its heavy duty bearings capable of withstanding both thrust and radial loads.
Ullage pressure for the hydraulic pump was accomplished using a commonly available D2028 12V DC air compressor and a series of check valves, allowing the reservoir to be periodically repressurized to a pressure of 0.2 MPa (30 PSI). This compressor was estimated to have a run time of 200 hours in the 100,000km design life of the vehicle, well below the several thousand hours expected brush life of the DC motor.
The reservoir was a custom design, using commercially available MDPE tube, with bonded HDPE end caps.
