Design And Property Research Of Artificial Muscle Driven By Tendon-sheath

Wearable rehabilitation assisted exoskeleton devices are increasingly needed in the current healthcare industry.However,most of the wearable exoskeletons on the market have the following disadvantages: large rigidity,unwieldy structure,and inconvenient control.And it is difficult to adapt to the way human generate force making the wearers uncomfortable.To solve the problems above,a novel tendon-sheath artificial muscle is proposed combining the tendonsheath transmission system with Hill muscle model.It is not only light but also as flexible as biological muscle.The contraction mode of biological muscle is simulated from the aspects of contraction principle and macroscopic mechanical characteristics which is intended to raise the comfort of the wearers.The microstructure of biological muscle is analyzed deeply and then simplified,and a suitable muscle model is selected as the design basis of the artificial muscle's overall mechanism.The principle of muscle contraction on micro-level is investigated and this paper is inspired to adopt a controllable collet to simulate muscle's contract way by the method in which cross-bridge is coupled with thin filament and dragged.The Macroscopic motion characteristic curve is achieved by biomechanical analysis and is considered to be the theoretical reference of the way muscle contracts.The scheme of the single and double artificial muscle's overall arrangement is determined according to Hill muscle model along with tendon-sheath transmission system.The collet of the artificial muscle is designed and calculated which includes self-locked collet,press component and control system's circuit.The heat of electromagnet is checked when the artificial muscle works continuously.The force and displacement model is deduced based on tendon-sheath statics model and the dynamic model of the artificial muscle is derived by simplifying it to a second-order system.The effect of series elasticity on absorbing shock load in artificial muscle is analyzed on the basis of the dynamic model.Additionally,the influence of series elasticity on system's close-loop control is also studied.The test platform of the artificial muscle is established to measure the properties of collet and the performances of several contraction modes and full-inspired tetanic contraction are simulated and tested on the platform.A control policy of the double artificial muscle's cooperative movement is raised realizing the coordination of the antagonistic muscle's continuous motion.A model of muscle's contraction force to elongation is also presented based on the statics model,and a brand-new sensorless force feedback control methods is come up with depended on the model.The result of the control effect shows that the control method is more accurate than traditional feedback control with force sensors.