Independent Study: Hin
Bike Lifting Mechanism for Non-destructive Interaction
Background
In our project, our KanGo device must be able to lifts different bikes securely, holds it in place during transportation, while not harming the bike. Current bike-holding devices for personal and autonomous bike storage often immobilize the entire bike, which is not suitable for our purposes.
Research Objective
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Requirements for bike lifting mechanism
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Flexibility on holding different bikes
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Minimal risk of bicycle damage
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Smooth user interaction
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Percieved bike security
Assumptions
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Bike’s front wheel will NOT remain contact with the KanGo.
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User’s bicycles would be road bikes or foldable bikes.
Basic Bike Measurements
Bar Height: the vertical distance from floor to the grip
Stack (Vertical) & Reach (Horizontal):
Distance between the bottom bracket axle and the top of the head tube
Insights
Bike Specifications
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For handlebars, depending on their types (flat / drop bars), the grip diameters varies from 22.2mm and 23.8mm to 25.4mm and 31.8mm.
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Below specifications are estimated by sampling 86 types of bikes sold from common bicycle brands in Hong Kong.
Weight Distribution
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Consider average bikes, F ≈ 49.97 N
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With heavier bikes, F can reach 69.4 N
Handlebar Mechanisms
While static handlebar holders could hold the handlebar well, they mainly relies on gravity and the bike may pop out when KanGo encounter road bumps. Hence, security design such as safety latch are required. At later stage, this could be combined with robotics gripper to provide enclosure on the top.
Sling Mechanisms
In terms of the bike’s stability, as the bike’s front wheel is inside KanGo, any swinging motion of it is undesirable. Achieving a stable vertical lifting motion requires a more powerful driver of the sling, which at the same time needs to counter the bike’s weight. Hence, considered the electricity required and the resulting interaction, it is not the optimal solution.
Passive Grasping
Requires activation force from user’s bike-pushing motion as a trigger
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User will need to push with a minimum velocity of 2m/s, which may increase error rates.
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Wires around the handlebar likely tangle with the passive gripper and damage the bike.
Given that similar resulting interaction can be still be achieved with pressure or force sensors, passive grasping mechanism is not preferred for KanGo.
Significance of Research
Most existing bike-holding devices or bike park designs restrict the bike's mobility, limiting the flexibility of bike parking. With the optimal lifting mechanism, KanGo has the potential to manipulate different bike models using a single device, hence provide a versatile and efficient solution for bike handling and transportation.