Research On The Lower Limb Phase Detection System And Its Application For Intelligent Prosthesis Control

With the increasing number of patients with lower limb amputation, the research on intelligent prosthesis technology becomes increasingly important. The purpose of the technology is to research and develop artificial intelligent electromechanical prosthesis with the world advanced level by the combination of intelligent control technology, microelectronics technology, computer control technology, mechanical design and manufacturing technology, biomedical engineering, medical engineering and rehabilitation technology.Phase detection is an important foundation for intelligent prosthesis control and rehabilitation robot control. It plays a decisive role on walking stability and gait symmetry of the patients. Therefore, research on lower limb phase detection has important academic and social significance. Most of existing phase detection methods are non-real-time, the detection result can be used for gait analysis. But to achieve the application of control, the detection system must be in real time. In addition, the number of sensors could affect the wearer comfort. A simple structure, portable wearable system is the goal of lower limb phase detection system. Aiming at these problems, the main contents are as follows:1. Gait analysis on experimental data by gait information collection experiments for healthy testers. Propose a gait phase division method based on the relationship between ankle torque and angle in a gait cycle and knee angle in a cycle and propose a gait phase detection method based on the gait phase division method.2. Choose appropriate force sensors and signal acquisition devices, build the signal acquisition circuit to realize the real-time force information collection. Choose appropriate attitude sensors and write the real-time angle acquisition program. Establish gait phase detection experimental system and build test platform. Three subjects join in the experimental research to verify if the system can adapt to different subjects, different speed and different gait stride.3. Build the control system based on the knee prosthesis in the lab to verify if the gait phase detection system can be applied to the intelligent knee prosthesis control Apply the gait phase detection system to intelligent knee prosthesis control, and conduct experimental research on if the knee prosthesis can follow the gait phase detection system and if it can adapt to the different speed when the subjects change their walking speed.A real-time gait phase detection method and its realization were proposed. The method combines foot force and knee angle information and extracts phase information in real-time. The number of sensors and tedious calculation for data integration were reduced. And the method can adapt to different speed, stride length and different subjects at the same time. Finally, the method was applied to the intelligent knee prosthesis control to validate the prosthesis can follow the gait phase detection system and adapt to different walking speed.