Drive Controls & Programming a Power Chair
- By Jay Doherty
- Nov 01, 2012
One of the most time-consuming parts of an evaluation
or fitting of a power wheelchair can be the custom
programming required to meet the consumer’s individual needs.
Programming can be one of the most intimidating parts of a fitting if
you are not comfortable with programming the power wheelchair’s
There are many different parameters to program, from driving
parameters to special features that allow a consumer independent
access to the electronics. The trick to making this easier is to understand
how the consumer wants and expects the power wheelchair to
drive or handle. This can only be understood through programming
the power base, then having the consumer control it, then perhaps
programming it some more.
There are so many different parameters available to fine-tune
how a power wheelchair drives and responds to the client’s input
commands. The first thing you need to keep in mind is how and
where the consumer has used a power wheelchair in the past and
what sorts of electronics are needed to drive his or her power wheelchair.
Answering these questions can allow you to have a better
understanding of exactly what the consumer’s expectations of the
wheelchair are going to be and how the wheelchair needs to be
programmed to respond and drive in different environments.
When programming driving parameters, it is important to
consider whether the input device is proportional or non-proportional.
If it is a proportional controller, then the consumer can make
fine adjustments to speeds and the way the power wheelchair handles
by adjusting how far the joystick is deflected in a certain direction.
This type of drive input device typically requires less up-front
programming, since the consumer has the ability to adjust the responsiveness
of the electronics through the amount of joystick deflection
provided, as well as adjust the speed pot knob to make changes to the
speed the wheelchair will travel.
A few of the parameters that are extremely important to consider
are all the speeds, accelerations and decelerations for all directions
of control. All of these parameters need to be adjusted specifically to
how the consumer wants the wheelchair to react. They may even need
to be different in each profile the consumer may use: for instance, an
indoor profile with slower speeds and an outdoor profile with faster,
more aggressive speeds. Keep in mind that there is a misconception
from time to time that a wheelchair should drive perfectly right out
of the box. It is our job as equipment providers and therapists to
adjust a wheelchair to the consumer’s individual needs. We should
always expect to make some changes to the programming for every
power wheelchair fitting we take part in. If we don’t make changes to
the programming, then the outcome for that wheelchair will be less
A good example of why this programming
is necessary for every fitting is an
equipment provider or therapist who
may work with two different individuals
with cerebral palsy. One individual may
be able to release the joystick quickly
when stopping the power wheelchair,
while the second may release the joystick
more slowly. The individual who can
release the joystick quickly to stop can
have the wheelchair programmed so
the wheelchair comes to a more gradual
stop. The individual with a slower reaction
time needs the deceleration turned
up higher in order to stop within a
safe distance. Every person is unique,
and therefore every wheelchair will be
Proportional Control Considerations
As an equipment provider or therapist, our goal should always be to
keep an individual driving with a proportional control for as long as
possible, as proportional controls provide the consumer with greater
control over the power wheelchair. The team should explore every
proportional control programming feature a manufacturer offers
before they change the input method to a non-proportional input
device. To do this, the team must be very familiar with the proportional
programming features offered.
A few of the features to be explored by the team may include
allowing changes to increase the size of the neutral zone of a joystick,
dampening or suppressing tremors to the joystick, reassigning each
direction the deflection of a joystick represents, or decreasing the
throw of a joystick required to reach maximum speed. Each of these
features has a place and can benefit a multitude of individuals who
drive power wheelchairs. We need to ensure that we are familiar with
each of these parameters and how they change the way in which the
joystick input device controls the power wheelchair.
Non-Proportional Control Considerations
When it comes to non-proportional input devices, the programming
for these devices will need to be set up very differently from a proportional
input device. A non-proportional device is on or off , and it does
not offer much speed control. Therefore, this type of input device does
not offer the fine adjustment that can be performed with a proportional
input device. People who use non-proportional input devices
typically have less control with their bodies and therefore fewer access
sites on their bodies.
When setting up programming for a non-proportional device, we
should consider offering a greater number of profiles for different
driving situations. A typical profile layout for a non-proportional
input device may appear as follows:
- Profile 1: Indoor driving and driving in tighter spaces
- Profile 2: Driving in hallways and larger spaces
- Profile 3: Driving outdoors, in very large open spaces
- Profile 4: Auxiliary functions (e.g., environmental controls,
computer access, or access through the input device for a communication
- Profile 5: Power seat functions
Once the decision has been made about how many profiles the
consumer would like, you can proceed with the setup of the driving
Programming of how the power wheelchair handles with a nonproportional
input device can significantly influence how much a
person uses and likes the power wheelchair. We need to look very
closely at all the environments that the person drives within and do
a good amount of fine-tuning with all driving parameters. Every
driving parameter should be adjusted or at least looked at while
considering how it will influence the wheelchair’s maneuverability in each environment.
Unlike a proportional input device, a non-proportional input
device will require a significant amount of time spent programming
each drive profile for the individual’s comfort level.
Beyond the drive parameters, there are many options to consider
with each non-proportional input device. You may need to program
multiple functions to be performed with one switch (e.g., on/off ,
mode changes, and emergency stop). It may be necessary to program
a specific way for a head array to control the power seat functions, or
the individual pressures needed for a sip-and-puff system. Setting
up the programming for a non-proportional input device can take a
great deal of time and investment by everyone on the team, so a big
commitment will be necessary.
Keep in mind you may need multiple appointments in order to maximize
the individual’s independence with the input method. Multiple
appointments does not mean the team is not good at programming,
but rather that the team is thorough and making sure the consumer is
getting the maximum independence out of the power wheelchair.
We need to remember that, in the end, the time we put in at the
beginning stages of a fitting provides a better outcome and a greater
level of independence for the consumer. And isn’t that why we all
joined this industry in the first place?
This article originally appeared in the November 2012 issue of Mobility Management.
Jay Doherty, OTR, ATP, is the clinical education manager for Pride Mobility Products Corp., Exeter, Pa. Jay can be reached via e-mail at email@example.com or by calling (800) 800-8586.