Measurement And Analysis Of Human Muscle Mechanical Properties During Lower-Limb Movements

The main goal of exoskeleton robot research is to repair and enhance the human body's motor ability.The coordination between exoskeleton and human movement is the key of affecting man-machine coupling performance such as wearing comfort,weight carrying capacity,movement flexibility,metabolic energy consumption and even human movement rehabilitation.Poor human-machine coordination will lead to motion interference or even hurt human body.The researches about exoskeletons for now have been mostly based on traditional robot theories;these exoskeleton designs unavoidably lead to movement interference,because of the ignorance on deformation,adaptation and energy storage in human muscle-skeleton system.Focusing on these shortcomings,this thesis has taken lower limb muscles(quadriceps femoris group)object to build concrete muscle mechanical model,aiming to absorb mechanical properties of quadriceps femoris group during movements.The work in this thesis is mainly about:Skeletal muscle is the constraint and power source in limb joint movements,the focus of this thesis is to bulid a skeletal muscle model by investigating knee joint movements.A mechanical model of quadriceps femoris muscle group was established by referring to human muscle physiology anatomy and Hill muscle model.The dynamic centralized parameter model of lower limb motion is constructed with the lower limb motion(as the carrier)and the knee joint angle(as the variable).Constant parameters are determined,by means of anthropometry,knee anatomy and digital image processing,Aiming at the solving and analysis of the equivalent mass,equivalent stiffness and equivalent damping parameters of quadriceps femoris group,this thesis designs a step response experiment based on the lower limb dynamics model.The dynamic responses of knee joint angle during freely releasing of the lower limb under different loadings are compared to verify the feasibility and accuracy of the dynamic model.By combining the numerical simulation and experiment of system nonlinearity,the normalized stiffness and damping of the lumped parameter system are identified,and then the mechanical model parameters of quadriceps group are calculated in reverse.In this thesis,a method for evaluating and calculating muscle energy consumption is presented and the evaluation of muscle nerve response delay is realized.By designing the straight-line walking experiment,this thesis compares the energy consumption from the energy consumption assessment method with the muscular oxygen saturation in muscle metabolism,and verifies the rationality of the method.By designing the impulse response experiment of lower limbs,the delay characteristic between nerve excitation and muscle force generation has been analyzed,and its numerical value has been estimated quantitatively.