A method for the field assessment of rolling resistance properties of manual wheelchairs

Abstract

This article presents an examination and validation of a method to measure the field deceleration of a manual wheelchair (MWC) and to calculate the rolling resistances properties of the front and rear wheels. This method was based on the measurements of the MWC deceleration for various load settings from a 3D accelerometer. A mechanical model of MWC deceleration was developed which allowed computing the rolling resistance factors of front and rear wheels on a tested surface. Four deceleration sets were conducted on two paths on the same ground to test the repeatability. Two other deceleration sets were conducted using different load settings to compute the rolling resistance parameters (RPs). The theoretical decelerations of three load settings were computed and compared with the measured decelerations. The results showed good repeatability (variations of measures represented 6-11% of the nominal values) and no statistical difference between the path results. The rolling RPs were computed and their confidence intervals were assessed. For the last three sets, no significant difference was found between the theoretical and measured decelerations. This method can determine the specific rolling resistance properties of the wheels of a MWC, and be employed to establish a catalogue of the rolling resistance properties of wheels on various surfaces.

Evaluation of wheelchair resistive forces during straight and turning trajectories across different wheelchair configurations using free-wheeling coast-down test

“…In addition, the effect of weight distribution on resistive loss varied according to the trajectory of motion. This result is consistent with those of Bascou et al, who studied rolling resistance of different wheelchair configurations and reported a 52 percent increase in the decelerations when the loads on the casters varied from 29 to 64 percent using the same wheelchair mass [14]. Similar observations were made by Sauret et al, who speculated that decelerations would continually increase as the distribution of total mass on the front wheels increased [16].…”

“…In Coutts' study, the decelerations during the first six trials were determined with an average CV of 7.1 percent on a hardwood floor [31]. Comparing the decelerations across studies is difficult since different coast-down studies used different wheelchair frames [14][15][16], wheels [13,16], and ground types [19,21,32]. However, with similar weight distribution (30% loading on casters), our deceleration values had a similar range as Sauret et al (from 0.05 to 0.25 m/s 2 ) on a hard, smooth surface [16].…”

“…The resistive losses of the wheelchair tires and entire wheelchair systems have been measured experimentally using component-level analysis [10], treadmill [11][12], dynamometer [13], and roll-down tests [8,[14][15][16]. Kauzlarich and Thacker demonstrated via both component and system analysis that rolling resistance is related to tire material, wheel radius, profile radius, and load on the wheel base [10].…”

“…For example, Hoffman et al used three timing sensors to measure decelerations on different wheelchair frames, wheel combinations, and ground surfaces [15]. Both Bascou et al [14] and Sauret et al [16] developed a mechanical model of MWC deceleration to describe the effect of mass distribution and ground surface on rolling resistance properties. These studies concluded that wheelchair configurations and surface conditions can significantly affect the rolling resistance [14][15][16].…”

“…Both Bascou et al [14] and Sauret et al [16] developed a mechanical model of MWC deceleration to describe the effect of mass distribution and ground surface on rolling resistance properties. These studies concluded that wheelchair configurations and surface conditions can significantly affect the rolling resistance [14][15][16]. While these coast-down tests have been capable of characterizing overall rolling resistance, the methods have been constrained to straight trajectories.…”