RU2032434C1 - Method for controlling lower extremity prosthesis and apparatus for carrying out same - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: this method is characterized by more accurate walking symmetry by varying tempo of walking with femur prosthesis which engages flexible member in beginning of transfer phase. Moment of force of this flexible member is directed towards point of flexure of genicular articulation. Disclosed method further prescribes measuring acceleration of receiving femur sleeve and selecting instant of actuating flexible member relative to instant of initiation of transfer phase with regard to measured acceleration. Apparatus for effecting disclosed method includes successively connected cylinder 5, piston 6 and pneumatic shock absorber made of ferromagnetic metal. Gap between piston and cylinder is filled up by magnetic liquid which functions as packer sandwiched in between shock absorber air spaces. Piston carries electric winding 11. EFFECT: excellent results. 2 cl, 2 dwg

Description

 The invention relates to medicine, namely to prosthetics and prosthetics.

 A known method of controlling the prosthesis of the lower limb in the phase of transfer using a balancing weight located in the cavity of the receiving sleeve of the lower leg and servomotor, leading to a change in the frequency of vibration of the lower leg. The disadvantages of this method include the fact that the design of the prosthesis is very bulky, contains a large mass.

 The closest way to control the lower limb prosthesis in the transfer phase is to create a moment of elastic element forces relative to the knee joint in the knee node.

 The disadvantages of the method include the lack of adjustment for that walk.

 A device for controlling a lower limb prosthesis is also known, comprising a pneumatic shock absorber with an electrically controlled valve, a walking speed sensor and a control system providing a degree of valve opening depending on the walking speed. The disadvantages of the device include an increase in energy consumption bypassing air through the valve.

 The aim of the invention is to increase walking by changing the pace of walking on the hip prosthesis.

 This goal is achieved in that the control of the hip prosthesis in the phase of transfer using the moment of elastic element forces relative to the knee hinge created in the knee assembly creates it towards bending in the phase of transfer, while the acceleration of the femoral sleeve and the moment the elastic element is turned on relative to the start of the phase of transfer are additionally measured set taking into account this acceleration.

 In the control device of the prosthesis of the lower limb, which contains a series-connected artificial foot, a thigh sleeve, an electrically controlled pneumatic shock absorber, a cylinder and a piston mechanically connected to the knee joints, a tibia angle sensor and a control system, a cylinder and a pneumatic shock absorber piston, are made of ferromagnetic material, the gap between the piston and the cylinder is filled with magnetic fluid to seal between the air cavities of the shock absorber, and on the piston there is an electric Skye winding.

 Figure 1 shows the hip prosthesis in an extended position; figure 2 is the same in a bent position.

 The prosthesis comprises an artificial foot 1, a lower leg sleeve 2, a knee joint 3, a receiving sleeve 4 of the thigh, a pneumatic shock absorber with magnetic fluid with a ferromagnetic cylinder 5, separated by a ferromagnetic piston 6, with a rod 7 into two cavities 8 and 9, filled with air and magnetic fluid 10 , an electric field winding 11 is placed on the piston 6, the leads 12 are led out through the hollow rod 7. The cylinder 5 is mechanically connected by the lower leg 2, and the piston 6 through the rod 7 and the hinge 13 with the receiving sleeve 4. The elastic seals 14 and 15 serve to seal the inner lower cavities of the shock absorber. The prosthesis also includes a sensor 17 measuring the angle of rotation of the lower leg 2 relative to the receiving sleeve 4. The sensors 16 and 17 and the field coil 11 are electrically connected to the control system 18. The piston 6 is moved down in the lower leg 2, while the volume of the cavity 8 has increased and the volume of the cavity 9 decreased.

 The prosthesis works as follows. In the transfer phase, the disabled person bends the stump, bending the lower leg with an artificial foot, leading to an increase in the angle between the thigh and lower leg, while the signals from the acceleration sensors 16, rotation angle 17 are fed to the control system 18, from which voltage is applied to the winding at a certain point in time excitation 11, and a magnetic flux is formed, which draws the magnetic fluid into the region of maximum magnetic induction, filling the annular gap between the piston 6 and the cylinder 5, thereby forming a magnetic fluid seal. In this case, the cavities 8 and 9 are hermetically separated from each other and with a further increase in the bending angle of the lower leg, the gas pressure in the cavity 9 increases and in the cavity 8 decreases, and the voltage on the field winding provides a sustained pressure drop of the magnetic fluid in excess of the maximum air pressure drop in cavities 8 and 9, as a result of this, air bypass through the magnetic fluid is impossible and the shock absorber works like a pneumatic spring, seeking to return the prosthesis to the extension phase. The moment of the pneumatic spring leads to a reduction in the extension time of the prosthesis, and the control system 18 supplies voltage to the excitation winding 11 after the start of flexion of the lower leg, the earlier the greater the acceleration of the thigh in the initial period of transfer. When the hip prosthesis is extended, the voltage is turned off.

 Advantages of the method and device over the base object: it was possible to change the pace of walking of a disabled person on a hip prosthesis; the duration of the moment of force of the air spring is directly dependent on the extension speed of the lower leg and thigh.

Claims (2)

 1. The way to control the prosthesis of the lower limb, which consists in creating in the phase of the transfer in the knee node a moment of elastic forces relative to the knee joint, characterized in that the moment of elastic force relative to the knee joint creates towards its bending in the transfer phase, while the acceleration of the receiving sleeve of the thigh is additionally measured and the moment of inclusion of the elastic element relative to the beginning of the transfer phase is set taking into account this acceleration.  2. A device for controlling the prosthesis of the lower limb, comprising a thigh receiving sleeve in series, an electrically controlled pneumatic shock absorber, the cylinder and piston of which are mechanically connected to the knee joints, a receiving sleeve acceleration sensor, characterized in that the cylinder and the pneumatic shock absorber piston are made of ferromagnetic material, moreover, the gap between the piston and the cylinder is filled with magnetic fluid to seal between the air cavities of the shock absorber, and located on the piston The electrical winding.

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