Active AFO with ankle joint brake friction control using force observer

Area of Science:

• Biomechanics
• Robotics
• Orthotics

Background:

• Stable gait is crucial for individuals using active ankle foot orthosis (AFO).
• Ankle joint brake friction control is essential for AFO-assisted stable locomotion.
• Existing systems may require complex or intrusive sensing mechanisms.

Purpose of the Study:

• To design and simulate an optimum friction control system for active ankle foot orthosis (AFO).
• To achieve precise brake friction control without utilizing force sensors.
• To enhance the robustness and practicality of AFOs.

Main Methods:

• Development of an optimum friction control system incorporating a force observer.
• Simulation of the control system's performance under various conditions.
• Control of brake friction proportional to the observed human force of the lower limb.

Main Results:

• The force observer demonstrated effective performance in estimating human limb forces.
• Simulated results confirmed the system's ability to achieve optimum friction control.
• The sensorless approach proved viable for AFO applications.

Conclusions:

• The developed force observer-based friction control system enables stable gait in AFO users.
• Eliminating the need for force sensors makes the active ankle foot orthosis more robust and practical.
• This sensorless approach represents a significant advancement in AFO technology.