Mobility Device Rear Wheel Swing Arm Angle Control
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Solution Overview
Problem
Existing mobility devices are bulky and complex, with a large footprint, and pose a risk for users with disabilities due to their balancing mechanisms, and their geometry can be affected by changes in wheel pair positions during use.
Innovation Solution
A mobility device with a main frame, drive wheel swing arms, rear wheel swing arm, and an actuating device that controls the rear wheel swing arm angle independently of the wheel motors, along with a body support system and inertial sensors to adjust the center of gravity for stability, reducing the footprint and enabling safe navigation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the mobility device uses a traditional fixed wheel configuration, then the structure is simple, but the footprint is large and cannot be reduced
Solution Approach 1:
The patent applies the dynamics principle by making the rear wheel swing arm angle adjustable through an actuating device, allowing the wheel configuration to change from fixed to dynamic. This enables the footprint to be reduced by pivoting the rear wheel swing arm while maintaining structural integrity through the pivot connection to the main frame.
Solution Approach 2:
The mobility device is segmented into independently controllable components: the rear wheel swing arm can be controlled separately from the drive wheels through the actuating device. This segmentation allows the rear wheel position to be adjusted independently to reduce footprint without affecting the drive wheel operation controlled by the wheel motors.
2Adaptability or versatility
If the mobility device includes balancing mechanisms for stair climbing, then the capability to climb obstacles is improved, but the device becomes bulky and complex
Solution Approach 1:
The balancing mechanism uses dynamic adjustment of the rear wheel swing arm angle to achieve stair climbing capability. The actuating device dynamically repositions the rear wheel swing arm to create the necessary geometry for obstacle negotiation, replacing complex mechanical balancing systems with a simpler angular control approach.
3Adaptability or versatility
If the wheel pairs can rotate independently to alter geometry, then the adaptability is improved, but the driving may be affected during position changes
Solution Approach 1:
The control system is segmented into independent control channels: the actuating device controls the rear wheel swing arm angle independently from the wheel motors that control drive wheel rotation. This independent control allows geometry adjustment without interfering with driving operations, maintaining reliability by preventing control conflicts.
Solution Approach 2:
The system performs preliminary action by adjusting the rear wheel swing arm angle to the desired position before initiating or during driving operations. This preliminary positioning ensures the geometry is optimized for the intended maneuver while maintaining stable driving control through the independent wheel motor system.
4Area of stationary object
If the rear wheel swing arm angle is controlled independently, then the footprint can be reduced, but the control system complexity increases
Solution Approach 1:
The actuating device that controls the rear wheel swing arm angle is integrated into the existing mobility device control architecture, serving multiple functions: footprint reduction through angle adjustment, stability enhancement via center of gravity control, and navigation improvement. This multi-functionality reduces the need for separate dedicated systems, mitigating control complexity.
Data Source
AI summary
A mobility device (1) comprising: a main frame (3), drive wheel swing arms (5) pivotally connected to the main frame (3), drive wheels (7) connected to a respective one of the drive wheel swing arms (5), wheel motors, each wheel motor being configured to drive a respective drive wheel (7), a rear wheel swing arm (9) pivotally connected to the main frame (3), a rear wheel (11) connected to the rear wheel swing arm (9), and an actuating device configured to control a rear wheel swing arm angle between the rear wheel swing arm (9) and the main frame (3) independently of control of the wheel motors.