Presentation on theme: "Prosthesis Design and Control"— Presentation transcript:
1 Prosthesis Design and Control IntroductionFall 2014
2 Stump, or residual limbEarliest amputation recorded by Herodotus, Greek historian, 480 BC Persian soldier Hegesistratus arrested by Spartans, facing torture and execution, one foot in stocks, cut off foot to escape, later obtained a prosthetic (wooden) foot
3 Disarticulation: Amputation between bone surfaces Upper limb amputations: 7%2%33%1%54%3%
4 Disease or infection – 74% Causes of amputationAccident – 23%Disease or infection – 74%Cancer – 2%Vascular (circulatory) – 54%Diabetes – 70%Tripled between 1980 and 2005Diabetic survival rate is improving1/3 of adults diabetic by 2050Birth defect – 3%Paralysis – less than 1%
5 As of 2014:2 million people with limb loss in the United States185,000 amputations in the United States each yearIn 2009, hospital costs associated with amputation totaled more than $8.3 billionAfrican‐Americans are four times more likely to have an amputation than white AmericansNearly half of those who have an amputation due to vascular disease die within 5 yearsDiabetics who have a leg amputation have a 55% of a second amputation within 3 years
6 Amputations by ageBelow 10 years old: 3%11-20 years old: 7%21-30 years old: 7%31-40 years old: 7%41-50 years old: 9%51-60 years old: 18%61-70 years old: 28%71-80 years old: 17%Over 80 years old: 4%A Primer on Limb Prosthetics, p. 9
7 Corset-style interface, pre-1960s Patellar-tendon-bearing socket, introduced in the 1960s
8 (Silesia is a region in Poland) Total elastic suspension belt Silesian bandage(Silesia is a region in Poland)Total elastic suspension beltPelvic beltamhs.org.au/Virtual Museum/Surgery/orthopedics/Limb-prostheses
9 Socket Knee Shank Ankle Foot Socket interfacesLiner / lock – low activitySuction – medium activityVacuum – high activitySocket Knee Shank Ankle FootMechanical interfaces between leg components are standard, which provides a “plug and play” prosthesis.
11 Lower limb amputee activity levels Does not have the ability or potential to ambulate safely and a prosthesis does not enhance their quality of life or mobility.Level 1The ability or potential to use a prosthesis for transfers or ambulation on level surfaces at fixed pace. This prosthesis is typical for the household ambulator.Level 2The ability or potential for ambulation with the ability to traverse low-level environmental barriers such as curbs, stairs, or uneven surfaces. This prosthesis is typical for the limited community ambulator.Level 3The ability or potential for ambulation with variable pace, with the ability to traverse most environmental barriers while participating in activities of daily living that require prosthetic use beyond simple locomotion.Level 4The ability or potential for prosthetic ambulation that exceeds basic ambulation skills, exhibiting high impact, stress, or energy levels. This prosthesis is typical of the child or active adult functioning in the community.
12 More than 50 models available today Some design for special activities Prosthetic FeetMore than 50 models available todaySome design for special activitiesFeet with no hinged parts: Low activity levelSolid ankle cushioned heel (SACH)Elastic keel: more flexible
13 Flex footOscar Pistorius, 2012 South African Olympic sprinter
15 Odyssey – motorized1 KHz controlJackSpring – motorizedThomas Sugar, ProfessorArizona State University
16 Prosthetic Knees More than 100 models available Single axis or polyaxialPassive: no electronicsMechanical frictionConstantVariableHydraulicPneumaticActive: motor controlSemi-active: computer control but no motorsOttobock, Ossur, Trulife, Freedom Innovations, Endolite (Dayton, Ohio), …medi OHP3/KHP3
17 Mauch SNS (swing and stance) OssurPassiveHydraulic$5,000Hans Adolph Mauch ( )German engineer until the end of WW IIJet engine and prosthesis development in GermanyMoved to USA in 1945
18 C-Leg Ottobock Semi-active Hydraulic Introduced in 1997 First microprocessor leg$50,000 retailOtto Bock,German prosthetist
19 Rheo Knee Ossur Semi-active Hydraulic Introduced in 2005 $17,000 Magnetorheological fluid has viscosity that depends on the surrounding magnetic field
21 Integrated knee and ankle motors Currently in testing Vanderbilt Leg(aka bionic leg, orGoldfarb leg)Freedom InnovationsIntegrated knee and ankle motorsCurrently in testingController gain scheduling depending on “walking phase”Image: National Institute of Biomedical Imaging and BioengineeringF. Sup et al., “Self-Contained Powered Knee and Ankle Prosthesis”
22 First active transfemoral prosthesis Power KneeOssurFirst active transfemoral prosthesisIntroduced in 2009$60,000proklinik.com.tr
23 Increase in energy consumption Amputee with walker or crutches – 65% Below-knee unilateral amputee – 15%Below-knee bilateral amputee – 30%Above-knee unilateral amputee – 65%Three times normal hip power on amputated sideAbove-knee bilateral amputee – 200%“Microprocessor Prosthetic Knees,” by D. Berry“Self-contained power knee and ankle prosthesis,” by F. Sup et al.
24 Coordinate system Z Y, right to left X Thigh angle (positive as shown) Direction of walkingZY, right to leftXKnee angle (positive)Thigh angle (positive as shown)
25 Able-Bodied Gait DataHeel StrikeToe OffFlexionExtensionStance PhaseSwing PhaseGait_Data_Sub3.xls, Normal Walk (Cleveland Clinic)
26 Able-Bodied Gait Data Positive: Power Generated by the Joint Negative: Power Absorbedby the JointDoes not match published data wellGait_Data_Sub3.xls, Normal Walk (Cleveland Clinic) kg subject
27 Power = Torque * (Angular Velocity) Normal walking speed ToeOff“Energy generation and absorption at the ankle and knee during fast, natural, and slow cadences,” by D. Winter, 1983Figure 3 and Table 1Able-Bodied Gait DataPower = Torque * (Angular Velocity)Normal walking speed104.4 steps/minute (52.2 strides/minute)Ankle work = – = 17.8 JKnee work = – – 9.6 – 8.4 = –20.6 JThe ankle requires energyThe knee absorbs energyThe net work done by the knee/angle combination is negativeDiscriminating age and disability effects in locomotion: neuromuscular adaptations in musculoskeletal pathology, by Chris A. McGibbon and David E. Krebs
28 Control group: dotted line More hip power required for amputees Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg® and Mauch SNS® prosthetic knees, by Ava D. Segal et al.2143Prosthetic LimbC-leg: solid lineMauch leg: dashed lineControl group: dotted lineMore hip power required for amputeesNo stance knee flexion in prosthesesMore negative knee power in prosthesesNo ankle push-off with prostheses
29 C-leg users: solid line Mauch leg users: dashed line Kinematic and kinetic comparisons of transfemoral amputee gait using C-Leg® and Mauch SNS® prosthetic knees, by Ava D. Segal et al.123Intact LimbC-leg users: solid lineMauch leg users: dashed lineControl group: dotted lineLimping (shorter steps) by amputeesMore hip power in amputeesMore ankle push-off by amputeesancillary health issues
30 Prosthetics Research at CSU Fall 2009 – Davis and van den Bogert (CC) contact Simon about hydraulic prosthesis controlSpring 2010 – CC provides funding to CSUSummer 2010 – Davis leaves CC for Austen BioInnovationFall 2010 – van den Bogert leaves CC for self-employmentFall 2011 –Richter begins design of hip robotSpring 2012 – Richter completes hip robotFall 2012 – CC project concludesFall 2012 – van den Bogert moves to CSUSummer 2013 – Wright Center funds CSU for 1 yearFall 2013 – NSF funds CSU for 4 years
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