The Bionic Arm. By Leslie Chataway and Christine Honey

Transcription

1 The Bionic Arm By Leslie Chataway and Christine Honey

2 BIONIC ARM Mechanics Control Current New Developments Future Directions 2

3 JOINTS / Articulations Classification Structure/ Movement Examples Synarthrodial (immovable) Amphiarthrodial (slightly moveable) Diarthrodial (freely moveable) Bones fused together Slight movement, fibrocartilage disk separates bones Inelastic ligaments cross and hold joint in place Cranial bones Vertebrae Tibiofibular joint Sacroiliac joint All other joints in body!

4 Synovial Joints! Freely moveable joints Important in study of Human Kinetics Cartilage surfaces bone, reduces friction and absorbs shock Joint enclosed by articular capsule that holds synovial fluid. Six types: hinge, ball and socket, pivot, condyloid, plane and saddle. 4

5 Synovial Joints in the Human Arm Type Pivot Hinge Condyloid Ball and Socket Movement Rotation, uniaxial Uniaxial movement Angular biaxial movement Triaxial movement with great ROM Example Radioulnar Elbow Wrist (metacarpophalangeal joint) Shoulder ROM: Range Of Motion 5

6 Classification of Movement Linear - simplest movement that can occur in a joint. Occurs in gliding synovial joints. Angular - motion occurs between the long bones of the arm, and spinal column. - angle between two bones is increased or decreased Angular 6

7 3 Cardinal Planes Frontal Plane 7

8 Linear Motion in Cardinal Planes Sideward motion travel along x axis (movement in transverse plane) Vertical motion travel along y axis (movement in frontal plane) For/Aft motion travel along z axis (movement in sagittal plane) Z Y X 8

9 Angular Movement in Cardinal Planes: Angular Movement occurs in the cardinal planes about an axis. Flexion/ Extension Abduction/ Adduction Medial/ Lateral Rotation Circumduction Forward Forward and backward movement of the arm in the sagittal plane, about a frontal axis. Horizontal occurs in transverse plane about a longitudinal axis. Sideward raising and lowering of the arm in the frontal plane about a sagittal axis. Arm Arm rotates inward and outward in transverse plane about a longitudinal axis. Involves Involves flexion/extension abduction and adduction performed in sequence in both sagittal and frontal plane 9

10 UNIAXIAL: The Elbow A HINGE JOINT Only movement in one plane of motion is possible. Can create a simple vector diagram to resolve the components of a force and measure the torque at the joint. Torque is the rotational force Torque = r x F = moment arm x Force 10

11 The Elbow: The Lever Third Class Lever - Muscle Force falls between Resistance and Axis FORCE Contrary to first and second class levers, the force to generate an output is greater for third class levers. Tasks are made easier because the effort only moves through a smaller distance to generate work. 11

12 Force Diagram The biceps force is broken down into a tangential and a radial force, these move and stabilize the joint respectively. 12

13 BIAXIAL: The Wrist A CONDYLOID JOINT Movements of the wrist joint are flexion, extension, hyperextension, abduction, adduction and circumduction Inertia is a measure of the resistance of a body to a change in rotary motion. Inertia = mr 2 13

14 TRIAXIAL: The Shoulder A BALL AND SOCKET JOINT Large range of motion exists for the shoulder girdle. Movements combine to create diagonal motion as well as segmental movements in the cardinal planes. 14

15 The Shoulder: The Force Diagram for a Lever can be extended to measure angular motion. 4 Spatial components of Angular Motion are: direction, radius, angle turned through, arc. Angular Motion : Amount of Rotation 15

16 "We We aren't doing a real great job with upper-limb prostheses. Our challenge is to restore function for people who have suffered limb loss." Dr. Todd Kuiken,, director of neuroengineering at the Center for Artificial Limbs at the Rehabilitation Institute of Chicago 16

17 CODMAN S PARADOX Attempting movements of flexion, extension, abduction and adduction through large ranges of motion is accompanied by rotation of the upper extremity (shoulder in this case) around its longitudinal axis (z). 17

18 What we learn from Codman s Paradox From the realization that none of the shoulder movements in the saggital and frontal planes can be classified as only one type of angular motion. It is now the goal of the Biomedical engineer to create a prosthesis that duplicates the skeletal framework, and allows rotation of the shoulder joint through hyper- movements of the upper and lower arm. 18

19 Nerves Dendrites - cell body - axon - collaterals - terminal branches - terminal buttons Refractory period after action potential in which no other potential can be generated 19

20 The Brain Visual field - prefrontal cortex - premotor cortex - motor cortex - spinal cord - motor neurons - muscles Sensory receptors - spinal cord - basal ganglia & cerebellum - sensory cortex 20

21 A Tetanus A twitch = a single action potential Fast Twitch Slow Twitch A tetanus = a series of action potentials Max force that can be exerted by a motor unit occurs during a fused tetanus 21

22 Fatigue Resistance to fatigue = the ability of a motor unit to withstand the decrease of the maximum force produced when a motor unit is required to produce a series of tetani Fatigue Index - used to determine classification of motor unit (Type S, FR or FF) 22

23 Tying it all together Muscle force is also increased by increasing the number of motor units involved Need to understand how and why the signal can increase from the brain Now focus in on the brachial plexus nerve (exits C5-C8 C8 & T1) which innervates the arm and upper back 23

24 The Human Arm The arm can be broken into Osteofascial compartments The arm is divided by a fascial layer that separates the muscles into an anterior and posterior compartments. The compartments contain muscles which are innervated by the same nerve and perform the same action. RADIAL NERVE: Posterior Compartment MUSCULOCUTANEOUS NERVE: Anterior Compartment MEDIAN NERVE: ULNAR NERVE: 24

25 RADIAL NERVE: Posterior Compartment Also known as the Extensor Compartment. The muscles in this compartment are the triceps brachii,, and anconeus muscle. The Radial nerve also controls the Extensor Carpi Radialis. The deep branch of the Radial nerve controls the extensor carpi radialis brevis,, and the supinator. The posterior interosseous nerve controls the extensors of the hand. 25

26 MUSCULOCUTANEOUS NERVE: Anterior Compartment Supplies the muscles in the anterior compartment, also known as the Flexor Compartment. The muscles in this compartment are the biceps brachii, brachialis,, and the coracobrachialis. The large Deltoid muscle is believed to have part of its body in the anterior compartment, the deltoid is the main adductor muscle. The protagonist of the deltoid muscle is the pectoralis muslces found in the chest. 26

27 MEDIAN NERVE: The Median Nerve controls the Pronator Teres, palmaris longus,, flexor carpal radialis. The Ulnar Nerve controls flexor carpal ulnaris, flexor digitorum profundus in the forearm and continues to the hand to control various functions of the fingers. 27

28 PROSTHESIS PAST Limb Prostheses are used as a substitute for a missing limb. Currently amputees will decide, based on their level of amputation, which type of prosthetic device: mechanical or electrical, will best suit the demands of their lifestyle. 28

29 Mechanical vs Electrical Each has its own advantages and disadvantages. For higher levels of amputation a hybrid design is often recommended. 29

30 Mechanical vs Electrical: Terminal devices play a large role in whether an amputee decides to choose a mechanical or electrical prosthesis. Terminal devices add functionality to the prosthesis. IE: myoelectric hand, mechanical cable-operated elbow, switch controlled electric wrist and a passive mechanical friction humeral rotation unit. 30

31 Mechanical: ADVANTAGES: Limb can be used in a variety of physical environments without enduring damage. High level of speed and accuracy DISADVANTAGES: Friction beneath holding harness can cause discomfort. Non-aesthetic 31

32 LTI Locking Shoulder Joint More Strength/Greater Resistance to wear Biomaterial: high strength aerospace alloys. 172 grams Natural gait, ability to lock every 10 degrees through a range of motion of 360 degrees. Second hinge allows for Ab/Adduction Joint frees manually, or by nudge control (use your imagination!) Available for use in both skeletal prosthetic systems. 32

33 Electrical: ADVANTAGES: Increased comfort due to suspension method. Higher level of pinch force (x5 of mechanical) Terminal devices can be introduced for increased functionality of prosthesis. DISADVANTAGES: Non-durable in many environments Slower operation than that of mechanical 33

34 The Electric Elbow Close hook using humeral flexion and bi-scapular abduction. Low Level Amputee Can be used with 34

35 Boston Digital Arm Prosthetic system incorporating microprocessor technology Most torque of any prosthetic on the market. Controls up to four additional prosthetic devices (hands, grippers, wrist rotators, shoulder lock actuators etc) sequentially through co-contraction contraction switching. On board microprocessor allows for suitable and unique control to be found at patients most optimal muscle site. Boston arm delivers more than 10ft-lbs of torque 2 pound hand device = 8 lbs active lift. Can lift 50 lbs while device is locked. Low level amputee 35

36 Prosthetics: a growing field! From Current to Future 36

37 The Bionic Arm By the Rehabilitation Institute of Chicago NECAL department - Dr. Todd Kuiken Successfully attached to four people Jesse Sullivan and Claudia Mitchell are our main focus 37

38 Jesse Sullivan Required bilateral shoulder disarticulation amputations Initially fitted with body-powered right arm, externally powered left arm Skin grafts became hyper-esthetic esthetic 38

39 Motor-Units of Focus Nerve Muscles Affected Movement New Chest Muscle Musculocutaneous Bicep Flexing elbow Clavicular head of pectoralis major median radial ulnar Pronator teres, flexor carpi radialis, palmaris longus & flexor digitorum superficialis Triceps brachii, brachioradialis, the extensor muscles of fingers and wrist Flexor carpi ulnaris, flexor digitorum profundus & the intrinsic muscles of the hand Opening and closing of the hand Extend the elbow and wrist Finger dexterity Upper segment of the sternal head of the pectoralis major Lower segment of the sternal head of the pectoralis major Pectoralis minor 39

40 The Innervation Results Strong contraction of musculocutaneous motor- unit 2 moderate contractions of median motor-unit weak contraction of radial motor unit no contraction of ulnar motor-unit 40

41 The Prosthetic LTI-Collier shoulder joint (touch pad controlled) Boston digital arm (64 bit computer in forearm for signal processing) wrist rotator Griefer terminal device 41

42 The Outcome Block movement test Clothes pin test Overall preferred Only drawback - does not function properly when Jesse sweats 42

43 An Added Bonus of Reinnervation Touching different parts of the chest feels like touching different parts of the phantom limb Currently feel pressure through the prosthetic Trying to acquire remaining sensations through the prosthetic 43

44 Claudia Mitchell World s first bionic woman More issues with adipose cells creating cross-talk in women than in men Implemented shielding and insulation on top of removal of fat cells 44

45 Current Projects Natural arm is capable of 22 discrete movements - prosthetic is currently at four Helps with further research on the plasticity of the brain Dr. Miguel Nicolelis is trying similar research with implantations as opposed to surface electrodes 45

46 PROSTHESIS FUTURE 46

47 Robot-aided Gait and Arm Therapy Task-oriented repetitive movements can improve muscular strength and movement coordination in patients with neurological disabilities. 47

48 Current work is focused on the development and evaluation of patient-cooperative control strategies. 48

49 Conclusion Reality of the Exoskeletal robot meeting the Bionic arm (not in battle) creating a hybrid of the two is not too far off. The United States Army has their hand in both operations, and the fusing of both projects is a possibility in the near future. 49