Users’ adaptations to the proportional speed control of a motorised walker

Abstract

Purpose

Speed control is commonly used to regulate the forces applied by motorised walkers (MW) and there are often situations where the speed targeted deviates from the preferred walking speed of its users, such as when encouraging higher walking speeds and due to safety consideration. This study investigates the effects of different MW’s target speeds on the selected walking speeds, force applied, perceived exertion, and gait of MW users during steady-state walking.

Materials and methods

The spatiotemporal gait parameters and perceived exertion of twenty young healthy participants were measured as they walked at a comfortable, self-selected speed using a MW as it was controlled to target forward speeds of 0.6, 0.8, 1.0, 1.2, and 1.4 m s⁻¹ as well as when no assistive force was applied by the MW.

Results

On average, users would walk slower when their “No Assist” walking speed is higher than the MW’s speed target and vice versa. Additionally, the force applied to the MW is proportional to the difference in speed, either faster or slower, when compared to "No Assist".

Conclusion

The user’s exertion and the energy used by the MW are both minimised when target speed is close to the preferred walking speed of the user. Additionally, these findings suggest that the speed target can be used to change the walking speed of users but only to a certain extend and at the cost of higher perceived exertion.

Implications for rehabilitation

• The larger the difference between the target speed of the MW and the preferred walking speed of the user, the more likely the user is to push or pull on the MW.

• Users would push or pull on the MW with a force proportional to the difference from their preferred walking speed even when matching the MW’s target speed.

• Users can be encouraged to walk at higher than preferred speeds, even though this would come at the cost of higher perceived exertion.

Keywords:

• Robotic rollators
• assistive devices
• proportional speed control

Disclosure statement

The authors report no conflict of interest.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the JSPS KAKENHI [Grant Number JP15K14619, JP17H01454, 21H04898, and 21K17791].