Introduction

1. A Portable Knee Ankle Foot Robot for Gait Rehabilitation Yu Haoyong, Huang Sunan, and Chen Gong A Novel Compact Compliant Actuator Introduction This project aims to develop and evaluate an intelligent compact and modular powered knee-ankle-foot orthosis for gait rehabilitation at outpatient and home settings. Stroke is among the top 10 causes of hospitalization in Singapore and a major cause of adult gait disability. Due to the brain plasticity, physical therapy is the main treatment for patients to regain motor function. However, physical therapy is labor intensive, limiting the availability and compliance, especially for patients at outpatient centers. Robots can help relieve the therapies from the strenuous work and improve the functional outcome. However, current rehabilitation robots are bulky, expensive and only available at large institutions. We aim to develop inexpensive, light weight and wearable devices for this group of patients. A novel compliant force control actuator has been developed for the robot as shown in figure 2. Using one soft spring at low speed output end and one stiff spring at high speed end, the actuator has high fidelity force control, low output impedance, and high bandwidth. Figure 3 shows the force tracking performance of the actuator. System Concept of the Robot Figure 2. The novel series elastic actuator Figure 1 shows the mechanical system design. The modular system consists of an ankle foot module and a knee module. The knee module can be removed from the system through the quick release joint when the system is used an ankle foot robot. When the user only needs knee assistance, the actuator for the ankle module can be easily removed from the system. Each module is driven with the same compact compliant force controllable actuator as shown in Figure 2. Figure 3. Force tracking Performance At 10 Hz Conclusion and Future Plan Experimental results for the actuator has proved its excellent force control performance. A functional prototype has been fabricated. We are currently doing sensor integration and controller design. We will conduct healthy subject test and move on the patient trial at the hospitals. Figure 1. System Concept Figure4. The Prototype