Optimization of stepped-cone CVT for Lower-Limb Exoskeletons

Publication date: Available online 11 July 2016 Source:Perspectives in Science Author(s): Ashish Singla, Baltej Singh Rupal, Gurvinder Singh Virk Wearable exoskeletons offer interesting possibilities to address the global concerns of the ageing society and hence many researchers and industries are investing significant resources to develop new innovations in the area of physical assistance. An important issue in providing effective physical assistance is how the needed torques can be generated efficiently and effectively. This paper considers this area and explores the use of continuous variable transmissions (CVT) for up-grading/downgrading torques so that the torque variations for performing motions of normal daily living can be provided. The knee joint is focused upon to develop the key stages of the CVT based approach in generating motion torques. From our on-going research to developing assistive exoskeletons for support activities of daily living it has been found that 6.3-20.6 Nm torque is required to provide 10-20% assistance at the knee joint of a healthy elderly person having weight 70-90 kg. The challenge here is to miniaturize conventional CVTs developed for the automobiles where large torques are needed. To achieve the required torque range for supporting human joints in various motions, a CVT is designed and its parameters optimized. Results are validated via a professional optimization software.

Source: Perspectives in Science - July 14, 2016 Category: Science Source Type: research