AS NZS ISO 7176.2:2020 – wheelchairs Part 2: Determination of dynamic stability of electrically powered wheelchairs
AS NZS ISO 7176.2:2020 – wheelchairs Part 2: Determination of dynamic stability of electrically powered wheelchairs.
EXAMPLE 2 For tiller-steered wheelchairs, a remote controlled proportional servo for the speed control and a spring load with a remote controlled release for the tiller so that when the tiller is released, the spring causes the tiller to turn on a predetermined radius (see Annex A). For tests requiring a variable turn radius required in 10.6, the steeritig tether can be replaced by an actuator, Alternatively, a device to limit the tiller rotation at predetermined turn angles can be used.
6 Initial set-up of test wheelchair
Prepare the test wheelchair in accordance with ISO 7176-22, set-up level 2, modified as specified in 6.2.
6.2 Anti-tip devices
Test the wheelchair with anti-tip devices lithey are provided and the instructions for use state that they are to be used. lithe anti-tip devices are adjustable, set them to their least effective position. If they can he adjusted so that they will not contact the ground if the wheelchair tips, this may he considered the least effective position.
If anti-tip devices are not provided, or the instructions for use do not state that they are to be used, test the wheelchair without them.
The wheelchair should he equipped with batteries as specified by the manufacturer. However, batteries containing free electrolyte can be hazardous If spillage occurs during testing. Such batteries may be replaced by the nearest capacity equivalent valveregulated, absorbent glass mat, or gel-type batteries. with supplementary weights if necessary to give an equivalent mass distribution.
6.4 Test load
Select the test load and set it up as specified in 6.4.2 or 6.4.3.
6.4.2 Test dummy
a) Select, position and secure the appropriate dummy in accordance with ISO 7176-22.
h) Set up the means to remotely control the wheelchair, if a remote control system is chosen. If using remote control, set up the means (see Annex A).
6.4.3 Human test occupant
For some tests, it might be necessary to use a human test occupant. For such cases, select a suitable human test occupant as specified In ISO 7176-22 and see Annex B for safety recommendations.
7 Test procedure
Conduct the tests specified in Clauses 8, 9 and 10 using the scoring system specified In Annex C to quantify the dynamic response of the wheelchair.
Wherever practicable, test using a test dummy as specified In 6.4.2. Where a test dummy can not he used, use a human test occupant as specified in 6.4.3.
8.3 Starting forward
NOTE This test determines stability when a wheelchair starts on a horizontal surface and on an uphill slope.
a) Position the wheelchair on the horizontal test plane.
b From a stationary position, operate the control device to give maximum acceleration in the forward direction.
c Observe the dynamic response of the wheelchair and score It according to Annex C.
d) Repeat b) and c) on the 30 6° and 10° ramps or other ramp angles as specified by the manufacturer or those commissioning the tests specifying requirements starting with the wheelchair on each ramp facing uphill. If the manufacturer recommends a technique for driving on a slope, test the wheelchair using the recommended technique. If the manufacturer specifies a maximum slope. testing Is to be done for all ramp angles up to and including that slope, otherwise the test methods are unmodified.
8.4 Braking when travelling forward on horizontal or uphill
NOTE This test dctcrmines stability wkieii a whckhir stops on a horizontil surfacc and rocks backward as a counter movement This test also determines stability when stopping on an uphill slope if the wheelchair rolls or rocks backward bclore coming to a complete stop.
a) Run the wheelchair at maximum forward speed on the horizontal test plane.
b) Apply retardation by releasing the control device.
c) Observe the dynamic response of the wheelchair and score it according to Annex C.
d) Repeat a) to c applying retardation by turning the wheelchair power off.
e) Repeat a) to c) applying retardation by quickly applying full speed command in the opposite direction, keeping the control device at maximum retardation until the wheels turn In the opposite direction.
1) Record the lowest score from the three methods of a) toe) and the method which gave this result.
g) Repeat a) to 1) travelling forward uphill on the 3°. 6° and l0 ramps or other ramp angles as specified by the manufacturer. lithe manufacturer recommends a technique for driving on a slope. test the wheelchair using the recommended technique. If the manufacturer specifies a maximum slope, testing is to he done up to that slope, otherwise the test methods are unmodified.
8.5 Braking when travelling backward
NOTE This test determines stability when a wheelchair stops suddenly from maximum reverse speed travelling on the horizontal and also travelling downhill travelling backward.