Design And Implementation Of A New Electric Stimulation Pulse Therapy Apparatus

As a kind of functional electrical stimulation equipment,electric pulse therapy apparatus has been widely used in the field of hemiplegic rehabilitation medicine,and has achieved good therapeutic effect.It’s safe,reliable,noninvasive and painless features have gained widespread acclaim and concem.Functional electrical stimulation is a method that outputs a set of ordered,specified intensity low frequency pulses to the body muscles in order to stimulate limbs to move and improve the function of limbs according to a predetermined program.At present,many electrical stimulation treatment equipment on the market have shortcomings of less targeted treatment and lower therapeutic effect.Therefore,it is of great significance to develop a new type of electric pulse therapy apparatus.For above problems,a new type of electric pulse therapy apparatus for hemiplegic patients has been designed in this thesis,which is characterized by using the EMG signals extracted from the surface of the patient’s limb as action attitude information,and outputing several strong,coordinated and orderly electrical pulses to the muscle group of patients for stimulating the affected limb to make the same normal limb movements as the healthy limbs.The therapy apparatus uses FPGA as control core chip.After amplifying and filtering,the surface EMG signals obtained from human limb are transferred to AD7689 to actualize A/D convert and transmit the data to PC by USB2.0.According to threshold voltage of the surface EMG signals and the sequential timing relationship of different muscles when they are contracted or relaxed,the corresponding parameter will be sent to FPGA through serial port.According to the parameter,FPGA generate several electric stimulation pulse through output circuits which can be used to stimulate the muscle group of affected limb.According to the intensity and timing relationship specified by the instructions,so that the patients can make walking action.By verifying the experiment in this thesis,the therapy apparatus has achieved the function of imitating limb movement by the affected limb.Compared with the traditional functional electrical stimulation,it effectively improves the treatment pertinence.By using the bi-directional square wave pulse for design,it has the advantages of less electrolysis under the skin when treated.It is more difficult to produce muscle tolerance,and it has better therapeutic effect.