Research On The Key Technology Of Intelligent Lower Limb Prosthesis Control

For the amputees,the lack of lower limbs not only makes them lose their basic sports ability in daily life,but also affects their physical and mental health with the atrophy and degeneration of the disabled limbs.Lower limb prosthesis can replace the motor function of the limb to a certain extent,so as to restore part of the motor ability of the lower limb amputees,so that the amputees can move freely like normal people.Not only can they regain their confidence in life,but also greatly facilitate their daily life,improve their living standards,return to their families with a full spirit,and contribute to the development of themselves and society.However,the gait of traditional mechanical lower limb prosthesis is rigid,and it is unable to adapt to different road conditions.This also causes the gait behavior of the wearer of mechanical lower limb prosthesis is unnatural and uncoordinated,and the wearer will feel tired and uncomfortable after wearing and using it for a long time.With the development of computer technology,intelligent lower limb prosthesis technology based on electronic sensors and adaptive control algorithm has been more and more widely studied.Intelligent lower limb prosthesis can be used for patients with lower limb amputa-tion to recover part or all of their walking function,so that amputees can move freely like normal people.The key problem to be solved is how to make the intelligent lower limb prosthesis actively perceive and accurately implement the patients' movement in-tention,and make the patients feel that the lower limb prosthesis is like a part of the human body.The key is to improve the level of human-computer hybrid intelligence.Let the patients and the lower limb prosthesis can interact freely.Let the lower limb prosthesis feel the environmental information,and pass it to the patients,to realize the integration of human and machine.In order to promote the development of the con-trol technology of the intelligent lower limb prosthesis,three key problems should be solved:1)As a man-machine coupling dynamic system,the lower limb prosthesis needs to face complex and changeable work conditions(different terrains,gaits,etc.),how to design the controller so that the lower limb prosthesis can cope with and achieve better balance control of the amputee;2)How to enhance people's perception and feedback to the environment and reconstruct the sensory feedback system of the lower limb prosthe-sis to make people feel that the lower limb prosthesis is like a part of the human body;3)How to actively perceive and accurately implement the patient's movement intention.In view of the above three key problems,the research is carried out from three aspects:1)A new control strategy based on time delay control is designed to make the lower limb prosthesis adapt to different working conditions and achieve better balance control of the amputee.Because of the high similarity between the biped robot and the human body in structure,the biped robot can simulate the control behavior of the human body better.In order to eliminate the influence of other parts of the human body(such as the driving,the healthy side leg,etc.)on the balance recovery,the biped robot is used to replace the amputee in the posture balance recovery experiment.The effectiveness of the controller is verified.2)In order to enhance people's perception and feedback to the environment and reconstruct the sensory feedback system of the lower limb prosthesis,a new strategy of sensory feedback reconstruction is proposed,which is based on non-invasive functional electrical stimulation.The effectiveness of the sensory feedback reconstruction strat-egy was verified by recruiting patients with thigh amputation and carrying out relevant experimental analysis.The patients can real-time perceive the rotation angle of the knee joint of the lower limb prosthesis and the change of the contact force between the lower limb prosthesis and the ground.3)Aiming at how the intelligent lower limb prosthesis can actively perceive and ac-curately execute the human motion intention,this paper studies and proposes a method combining the force sensor and IMU attitude sensor to perceive and predict the human motion intention by using the human motion information and multi-sensor signals of the lower limb prosthesis,so as to realize the motion control of the intelligent lower limb prosthesis.