Power Wheelchairs The Impact of Drive Wheel Location on Performance

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1 Power Wheelchairs The Impact of Drive Wheel Location on Performance Workshop Objectives Explain the characteristics of front, center and rear wheel drive chairs Provide information that will help you to short list chairs that are likely to be appropriate for your client Catch three of you napping during the afternoon Power Chair Geneology Electric Wheelchair Power Chair Geneology Front Wheel Drive Power Chair Geneology RWD but different Power Chair Geneology Mid Wheel Drive 1

Power Chair Geneology Mid Wheel Drive but different Power Chair Classification Power Wheelchairs Rear Wheel Drive Mid Wheel Drive Front Wheel Drive New Power Chair Classification Power Wheelchairs

Shoprider Spitfire Quantum Blast, C350 Ranger Badger RWD, 940S Quickie 121, 200, 222, 521, 525 Invacare Nutron, P7E, P9000, Ranger II, Storm Series Low ratio High ratio High ratio Low ratio High

2 Power Chair Geneology Mid Wheel Drive but different Power Chair Classification Power Wheelchairs Rear Wheel Drive Mid Wheel Drive Front Wheel Drive New Power Chair Classification Power Wheelchairs Rear Wheel Drive Centre Wheel Drive Front Wheel Drive Low Ratio RWD Approximately 60% weight on drive wheels 21 st Century Scientific Bounder Electric mobility Viva Handicare Alex Permobil Trax Shoprider Spitfire Quantum Blast, C350 Ranger Badger RWD, 940S Quickie 121, 200, 222, 521, 525 Invacare Nutron, P7E, P9000, Ranger II, Storm Series Low ratio High ratio High ratio Low ratio High Ratio RWD 75 to 85% weight on drive wheels Quickie P200, P222, 424, S626, S646, Xplore 2, S-6 series Invacare Storm series, Xterra Quantum Vibe, Rival CWD Weight on drive wheels varies Permobil M300 Frontier Levo Combi Invacare Pronto, M6, Xterra, TDX Quantum Q600, Q 6000, Q6 Edge, Q610 Quickie 424, 626, Freestyle, Xperience,Q710, Xcel2 2

High Ratio FWD 75 to 85% weight on drive wheels Levo C3 Pride Jazzy@ *, Q1450 Low Ratio FWD Approximately 60% weight on drive wheels Invacare Excel, Storm FWD, Ranger II FWD, FDX series Permobil

3 High Ratio FWD 75 to 85% weight on drive wheels Levo C3 Pride *, Q1450 Low Ratio FWD Approximately 60% weight on drive wheels Invacare Excel, Storm FWD, Ranger II FWD, FDX series Permobil Corpus, MPS, C500, F series Handicare Alex Teftec OmegaTrac Ranger Badger FWD, 804 New Power Chair Classification New Power Chair Classification Power Wheelchairs Rear Wheel Drive Centre Wheel Drive Front Wheel Drive Rear Wheel Drive Mid Wheel Drive Front Wheel Drive High ratio High ratio RWD biased CWD FWD biased CWD Performance Analysis Indoor Performance Analysis Indoor Low ratio RWD High ratio RWD CWD High ratio FWD Low ratio FWD KK JJJ JJJ JJJ KK Speed Handling Size Manoeuverability Rate of turn Turning radius 3 point turn Shape of space Corridors and doors Visual cues and ease of learning 3

Performance Analysis Indoor Ian Alan Low ratio RWD KK L High ratio RWD JJJ L CWD JJJ JJJ High ratio FWD JJJ KK Low ratio FWD KK KK Performance Analysis Indoor Ian Alan Low ratio RWD KK L High ratio

4 Performance Analysis Indoor Ian Alan Low ratio RWD KK L High ratio RWD JJJ L CWD JJJ JJJ High ratio FWD JJJ KK Low ratio FWD KK KK Performance Analysis Indoor Ian Alan Low ratio RWD KK L High ratio RWD JJJ L CWD JJJ JJJ High ratio FWD JJJ KK Low ratio FWD KK KK Chair Dimensions and Centre's Determine Characteristics Typical Chair Length & Radius Length Turning Radius LR RWD HR RWD CWD HR FWD LR FWD Chair Centre's Relative Position LR RWD 4

5 Relative Position HR RWD Relative Position CWD Relative Position HR FWD Relative Position LR FWD Scooter Centres Important Centres for Indoors 5

6 Turning Circle Typical Chair Length & Radius Length Turning Radius LR RWD HR RWD CWD HR RWD LR FWD Most chairs are 24 to 25.5 wide Typical Scooter Length & Radius L W Radius Space to Turn Around 3 wheel FWD wheel RWD wheel RWD Shape of space Shape of space 6

7 Corridors and doors Corridors and doors Visual Cues Perceived Rate of Turn Performance Analysis Outdoor Summary Ian Alan LR RWD KK L HR RWD JJJ L CWD KK KK HR FWD KK JJJ LR FWD L JJJ 7

Summary Ian Alan LR RWD KK L HR RWD JJJ L CWD KK KK HR

Considerations Speed Handling Curbs Curb cuts Hills

Soft Terrain Comfort Power and Centres Determine Outdoor

8 Summary Ian Alan LR RWD KK L HR RWD JJJ L CWD KK KK HR FWD KK JJJ LR FWD L JJJ Outdoor Performance Considerations Speed Handling Curbs Curb cuts Hills Acceleration / Braking Tracking Changing Direction Range Soft Terrain Comfort Power and Centres Determine Outdoor Performance RWD Centre of Gravity FWD Centre of Gravity CWD Centre of Gravity 8

Calculating Centre of Gravity Speed S626 Speed 11 km/h Distance

m Time 14m 40s Cross Oak 11s Performance Analysis Outdoor

best handling characteristics CWD JK Good handling

HR FWD K Fairly neutral but some tendency to oversteer when

when challenged No active element Active element Up Curbs Curb

9 Calculating Centre of Gravity Speed S626 Speed 11 km/h Distance 836 m Time 4m 50s Cross Oak 7s S525 Speed 7 km/h Distance 1686 m Time 14m 40s Cross Oak 11s Performance Analysis Outdoor Handling LR RWD K Tendency to understeer HR RWD J Generally the best handling characteristics CWD JK Good handling characteristics as long as weight on drive wheels. HR FWD K Fairly neutral but some tendency to oversteer when challenged LR RWD L Strong tendency to oversteer particularly when challenged No active element Active element Up Curbs Curb cuts Inclines Determined by: Centre of gravity location relative to drive wheels Traction Power 9

C of G relative to drive wheels Ascending moves

wheels Descending moves the c of g forward C of G

on a side slope produces specific tendencies to

wheelie sooner and lose traction A FWD chair will

Vertical C of G Both chairs will lose traction

10 C of G relative to drive wheels Ascending moves the c of g rearward C of G relative to drive wheels Descending moves the c of g forward C of G relative to drive wheels Maximum Traction Driving on a side slope produces specific tendencies to turn Impact of Vertical C of G A RWD chair will wheelie sooner and lose traction A FWD chair will tip forwards sooner and lose a rider Impact of Vertical C of G Both chairs will lose traction sooner, the FWD will spin it s wheels, the RWD will become a toboggan 10

Performance Analysis Outdoor Acceleration / Deceleration Tracking Flat level ground - equal Cambered sidewalk - HR and CWD better Uneven terrain - HR and RWD better Tracking Cambered

Moderate descent regenerates 0-5 amps Not moving, power on 0.1 to 0.

11 Performance Analysis Outdoor Acceleration / Deceleration Tracking Flat level ground - equal Cambered sidewalk - HR and CWD better Uneven terrain - HR and RWD better Tracking Cambered sidewalk - HR and CWD better Range (Gas tank) Model Capacity Amp hr Weight - kg (lb) U-1 Gel (27) 22NF Gel (37) 24 Gel (52) 27 Gel (63) Range (Current draw) Moderate descent regenerates 0-5 amps Not moving, power on 0.1 to 0.3 amps Full speed level ground 8 to 12 amps Starting out, changing direction amps Moderate ascent 40 to 80 amps Soft Terrain RWD tend to push casters down. HR chairs tend to be better initially but lose traction due to aux wheels digging in and high centering chair. FWD tends to pull casters up and out 11

12 Comfort Comfort of Ride Static Comfort Seating and Positioning Dynamic Comfort Reduce shock Reduce vibration Reduce vertical displacement Reduce pitching Representation of Bicycle Going over a Bump Displacement Going over a Bump Tire Diameter Over front wheel Between wheels Over rear wheel 12

13 Path Followed be Tire Path Followed by Anything Directly Above the Tire Distance Time Suspension Reduces Displacement Suspension Reduces Displacement Distance Time Air Filled Tires Reduce Displacement Air Filled Tires Reduce Displacement 13

14 Air Filled Tires Reduce Displacement Air Filled Tires Reduce Displacement Distance Time Solid Tires Transmit Shock Air Filled Tires Absorb Shock LR RWD Speed Bump 16 degrees 20 of travel HR RWD Speed Bump 20 degrees 16 of travel 14

15 Fail CWD Speed Bump No Suspension 23 degrees 4 of travel CWD Speed Bump Partial Suspension No pitching CWD Speed Bump Full Suspension HR FWD Speed Bump 16 degrees 21 of travel 14 degrees 24 of travel LR FWD Speed Bump 9 degrees 36 of travel Scooter Speed Bump 15

16 Ultimate Comfort Tilt and Recline Long wheelbase Large diameter wheels Pneumatic tires Suspension Head as far away from point of contact Tilt and Recline Tilt and Recline Tilt Recline Recline + Elevating legs Tilt and Recline Tilt and Recline Recline and Leg Elevation Consequences 16

Tilt and Recline Recline and Leg Elevation Solution Tilt and Recline Recline and Leg Elevation Solution Tilt and Recline (RESNA) Ramifications Postural Realignment and Function Physiological

17 Tilt and Recline Recline and Leg Elevation Solution Tilt and Recline Recline and Leg Elevation Solution Tilt and Recline (RESNA) Ramifications Postural Realignment and Function Physiological Implications Transfers and Biomechanical Issues Spasticity Contractures and Orthopedic Deformities Oedema Pressure Relief Pain and Fatigue Dynamic Movement Tilt and Recline (Michelle L Lange) Tilt Benefits To distribute pressure to reduce risk of pressure sores, increase comfort, and increase sitting tolerance. Maintaining the physical angles can inhibit muscle tone. To maintain posture and contact with seating when changing weight distribution. To prevent sheer. - particularly important in - a molded seat. - To maintain proper position of related devices such as a joystick, communication device, computer, and access switches. Allow for range-of-motion limitations prohibit a recline system, such as hip flexors, hamstrings, or even heterotopic ossification. Tilt and Recline (Michelle L Lange) Tilt Drawbacks client must move away from a desk or table to tilt, or the armrests or footrests may contact the table, possibly even tip it over, or at least hurt the client's feet. Most tilt systems do not include a stop switch if the client contacts an obstacle. If the client is at high risk for pressure sores. Tilt systems do not provide as much pressure relief as 180 degrees of recline. If the client is having bladder-emptying problems or wears a leg bag. Remaining in a fixed position) can constrict the bladder, and tilting with a leg bag can lead to leakage. Any items left on a tray during a tilt will slip and fall. Many tilt systems raise the seat-to-floor height, which affects transfers and the ability get under tables. Into mini vans etc. Tilt and Recline (Michelle L Lange) Recline Benefits Reduce risk of pressure sores, increase comfort/sitting tolerance. Provide passive range of motion at the hips and knees. When a client uses a tray for eating or work and needs to shift position regularly without disturbing the setup. Assist bladder function. Intermittent catheterization is easier in a reclined position. Alleviate orthostatic hypotension. Elevating legrests may assist with edema control and increased circulation in the lower extremities. 17

Tilt and Recline (Michelle L Lange) Recline Drawbacks Opening the seat-to-back angle can elicit

Persons with a contoured seating system could experience significant problems due to shearing.

Match anticipated uses to configuration.

Dongles PC programming tools Programming Only allow fine tuning, performance envelope is already set

to be able to programme Clinicians should know how they want the chair to be changed Programming

18 Tilt and Recline (Michelle L Lange) Recline Drawbacks Opening the seat-to-back angle can elicit flexor or extensor spasms. Persons with limited range of motion at the hips or knees. Persons with a contoured seating system could experience significant problems due to shearing. Programming Steps in process Meet seating needs of the client. Determine best input device. Match anticipated uses to configuration. Make mechanical adjustments Adjust programming Programming Can be performed with:- Programmers Dongles PC programming tools Programming Only allow fine tuning, performance envelope is already set Programmability varies from chair to chair Programmers/Dongles cost about $500 Clinicians do not need to be able to programme Clinicians should know how they want the chair to be changed Programming Acceleration Speed Braking Programming Parameters that set limits Forward Speed Min Forward Speed(speed dial only) Turning speed Reverse speed Min Reverse Speed (speed dial only) Power level / Power reduction 18

19 Programming Parameters that set rates Acceleration Braking / Decelleration Torque Level (Invacare) Turning Acceleration / Sensitivity Calibrations Joystick throw Sip and puff values Axes selection Motor output balance / Steer correct Parking brake delay Battery level Programming Function Control Switch control e.g. sip and puff Tilt and recline Latch mode / Momentary / Multi Step / Cruise Chair type Standby Standby time Sound RIM Control 19

New Definition NEW DEFINITION. (1 of 9)12/30/2006 3:33:53 PM. GF Strong Rehab Centre 4255 Laurel Street Vancouver BC V5Z 2G9

New Definition NEW DEFINITION. (1 of 9)12/30/2006 3:33:53 PM. GF Strong Rehab Centre 4255 Laurel Street Vancouver BC V5Z 2G9 Assistive Technology & Seating Service Vancouver Coastal Health GF Strong Rehab Centre 4255 Laurel Street Vancouver BC V5Z 2G9 New Definition Grouping or classifying any large collection of items is a