Multi-Pivot Tilt Mechanism for Hand-Free Wheelchair Control
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Solution Overview
Problem
Existing mobility devices, such as wheelchairs, are not easily operable by users with significant limb impairments and are not suitable for use on various surface types, including soft and undulating surfaces, as they require hand controls and lack fine control mechanisms for navigation in crowded areas or off-road use.
Innovation Solution
A powered mobility device with a tilt mechanism featuring multiple pivots, allowing users to drive and steer without hands, utilizing independently driven wheels, a weight displacement sensor, and a tilt mechanism with primary, secondary, and tertiary pivots to control movement and steering through body weight displacement, along with a hydraulic system for seat movement regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single pivoting mechanism is used for controlling forward and backward movement, then the device complexity is reduced, but the ease of operation deteriorates because users with limb impairments cannot easily operate it
Solution Approach 1:
The system uses the user's own body weight displacement as the control input, eliminating the need for external hand controls. The weight displacement sensor detects natural shifts in user position and automatically converts them into drive commands, making the device self-adapting to the user's movements without requiring complex control mechanisms
Solution Approach 2:
The patent replaces traditional mechanical hand controls with a sensor-based detection system. Instead of requiring manual manipulation of mechanical levers or joysticks, the system uses weight displacement sensors to detect user intent and electronically controls the drive wheels, substituting mechanical control with sensor-electronic-actuator systems
2Ease of operation
If hand controls are used for steering and propulsion, then the device complexity is reduced, but the ease of operation deteriorates for users with significant limb impairment
Solution Approach 1:
The system uses the user's own body weight displacement as the control input, eliminating the need for external hand controls. The weight displacement sensor detects natural shifts in user position and automatically converts them into drive commands, making the device self-adapting to the user's movements without requiring complex control mechanisms
Solution Approach 2:
The patent replaces traditional mechanical hand controls with a sensor-based detection system. Instead of requiring manual manipulation of mechanical levers or joysticks, the system uses weight displacement sensors to detect user intent and electronically controls the drive wheels, substituting mechanical control with sensor-electronic-actuator systems
3Measurement precision
If a simple tilt mechanism is used, then the device complexity is reduced, but the measurement precision deteriorates for detecting fine weight displacement control
Solution Approach 1:
The tilt mechanism is divided into multiple independent pivot points (primary pivot for forward/backward tilt, secondary pivot for lateral tilt, tertiary pivot for fine adjustment). Each pivot is equipped with its own sensor, allowing the system to detect and process weight displacement in different directions independently, thereby achieving fine control precision through segmented measurement
Solution Approach 2:
The patent introduces intermediate mechanical elements (linkages, levers, and pivot mechanisms) between the user's weight displacement and the final tilt output. These intermediaries amplify and refine the control signal, allowing small weight shifts to produce precise, controlled movements while the sensors detect the intermediate positions with high accuracy
4Reliability
If traditional wheelchairs are used on soft surfaces, then the device complexity is reduced, but the reliability deteriorates as they get stuck and require assistance
Solution Approach 1:
The patent implements a dynamic tilt mechanism that continuously adjusts the seat angle in response to terrain conditions and user input. The multiple pivots allow the seat to adapt its orientation to maintain optimal wheel contact with the ground on varying surfaces, from hard floors to soft lawns, preventing the device from getting stuck without requiring complex external assistance systems
Data Source
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AI summary
A powered wheelchair 100 with a tilt mechanism having multiple pivots that allows the wheelchair 100 to be driven and steered with or without the use of hands. The wheelchair 100 has two spaced apart drive wheels 101, each mounted to a separate shaft 104 that is independent of the other drive wheel. A drive controller drivingly coupled to the shafts 104 and the drive controller is housed within a base 102 that is pivotally situated on the shafts 104. A seat 103 mounted on a tilt mechanism enables the seat to tilt in a forward, backward, left and right direction as a result of the user displacing their body weight in either of those directions. The tilt mechanism includes three pivots, a primary pivot P1, secondary pivot P2 and tertiary pivot P3. The primary pivot P1 pivotally connects the base 102 to the shafts 104. The secondary pivot P2 is situated above and adjacent the base 102 so that the respective ends of the rod 105 are pivotally connected to the base 102. The tilt mechanism and the drive controller are connected to a weight displacement sensor to control the movement and direction of travel of the wheelchair 100.