# A Rigid-Flexible Coupled Lower Limb Exoskeleton for Enhancing Load-Bearing Ambulation

## TL;DR

This paper introduces a lower limb exoskeleton that combines rigid and flexible structures to improve load-bearing walking while reducing energy use.

## Contribution

The novel rigid-flexible coupling design enhances load transfer and reduces metabolic costs during weight-bearing ambulation.

## Key findings

- The exoskeleton achieved 90.48% load transfer at 10 kg during static standing.
- Metabolic costs were reduced by 21.61% with exoskeleton assistance ON compared to no exoskeleton.
- Assist ON mode reduced metabolic costs by 13.22% compared to Assist OFF mode.

## Abstract

Lower limb exoskeletons significantly enhance human functionality. However, simultaneously improving the load capacity of these devices while reducing metabolic costs presents a major challenge in the industry. This paper presents a lower limb exoskeleton that integrates both rigid and flexible structures to facilitate active assistance and passive load transfer at the hip joint. The load transfer experiments were conducted with weights of 10 kg and 15 kg. During static standing, the load transfer rates were recorded at 90.48% and 69.70%, respectively. In dynamic walking, these rates decreased to 62.07% and 43.69%. Furthermore, in metabolic experiments involving a load of 15 kg, metabolic costs in the exoskeleton assistance modes OFF (Assist OFF) and exoskeleton assistance ON (Assist ON) were reduced by 8.3% and 21.61%, respectively, compared to the exoskeleton-free condition (NE). Furthermore, the Assist ON mode further decreased metabolic costs by 13.22% compared to the Assist OFF mode. These findings demonstrate that the rigid-soft coupled lower limb exoskeleton exhibits exceptional load transfer capabilities and effective assistance, highlighting its potential to enhance human performance in weight-bearing activities.