Tire Deformation-Based Regulation of Braking Torque in Manual Wheelchairs Equipped with Reverse Locking Modules

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Assistive Technology

Background:

• Manual wheelchair mobility faces challenges with architectural and terrain barriers, particularly slopes.
• Climbing slopes is strenuous and poses a high risk of instability for wheelchair users.
• Existing braking systems often rely on contact force, which can be less reliable than tire deformation.

Purpose of the Study:

• To develop and validate a novel regulation method for wheelchair braking torque based on tire deformation.
• To establish a measurement procedure for determining braking torque using tire deformation.
• To analyze the relationship between tire deformation, user mass, and braking performance.

Main Methods:

• Three experimental tests were conducted: sliding force moment (E1), braking torque (E2), and tire deformation (E3).
• A mathematical analysis was performed to model braking torque as a function of tire deformation.
• Analysis of Variance (ANOVA) was used to assess the significance of various factors on braking torque.

Main Results:

• A measurement procedure was formulated to quantify braking torque via tire deformation.
• For 24''x1'' wheels (4-7 bar pressure), specific tire deformations were correlated with braking torques of 7.5 Nm and 12 Nm.
• User mass significantly impacted sliding force, and both contact force and roller diameter influenced braking torque.

Conclusions:

• The developed method accurately measures wheelchair braking torque using tire deformation, with a model error of 3% to 7%.
• This tire deformation-based approach offers a more reliable and potentially safer braking solution for manual wheelchairs.
• The findings contribute to improved wheelchair design and user safety, particularly for slope navigation.