When you’re first starting out, I recommend putting it in the slowest speed possible and lining up the chair with the ramp. Focus on an object straight ahead. You may want to practice on a flat surface first just to make sure you can drive in a straight line.
For a few days my pALS had me mount an older cell phone on the back of the wheelchair. It had camera software on it. PALS had a tablet with him to look at and could see on this tablet what the phone camera recorded: i.e. the distance between back of wheelchair or other objects like wall, door frame etc.
After doing it for a few days and checking w the tablet/ phone camera he had a better sense for driving backwards w. turns etc.
I have found that power wheelchairs have the ability to go over terrain that far exceeds the specifications for ADA compliance.
I can go up much steeper inclines than ADA specifies. There are a few things to keep in mind, though.
When transitioning from a flat section to an inclined section, the angle of the transition is significant. Some wheelchairs can handle more acute transitions than others.
My first wheelchair is front wheel drive and had anti tipping wheels installed in front. When I would try to make the transition from level ground to a ramp when the transition angle was more acute (a steep incline), the anti tipping wheels would contact the ramp and effectively lift my drive wheels off the ground. Thus, I would have no traction on the drive wheels and was stuck like an upside down turtle.
After reading a bit, I discovered that many folks with front anti tipping wheels removed them. I did so and it made an enormous difference. I can now transition to a pretty acute incline without any problem. In some cases, I have to raise my footrests or tilt the entire seat backwards so that the footrests would be clear of the ramp. This is the case either going uphill onto a ramp or downhill off of a ramp.
I also learned that carrying momentum into a ramp is a good thing, so long as the width and straightness of the ramp can accommodate the necessary speeds.
Another thing I learned is that when going down a steep ramp or slope, Gravity pulls me so that I slide forward in the chair. To help prevent this, I always wear my "seat belt", which is really just a body posturing device. I also will tilt the seat backwards so I am sitting level.
Another issue I initially had with going uphill is that the wheelchair would stall way too soon. My first wheelchair has high speed motors, which reduces the torque with normal settings. NuMotion was able to adjust the torque setting, which effectively increased the motor compensation, so that I could go up steep inclines. There is still a limit to what I can go up, but the increased torque setting makes a big difference.
Finally, I found that slowly going over a threshold (or any bump) at very low speeds just did not work. I found that if I hit the obstacle with some speed (say, 1 or 2 miles per hour), my momentum would carry me over the obstacle. Of course, that was pretty hazardous for the wall I would run into when coming into our house.
Increasing the torque setting on the wheelchair largely, but not completely, solved this problem. I found that approaching the bump at an angle so that only one wheel was climbing over it at a time really helped. I still do that on a regular basis.
I have found that experience has made the greatest difference. I have ridden my wheelchairs a lot and the experience I have gained doing that allows me to relatively comfortably handle situations that I would have found impossible in the first month of driving.
Please make sure you are lined up with the ramp going up and down. DH recently got a head array for the chair he's had for over 2 years. It is different than driving with a joystick and has a learning curve. We had a 30" wide x 36" long ramp with 2" lips on either side in our house because of a step-down from the kitchen to the family room. He almost went over the side of the ramp a few times - tilted up over the lip - and it's really scary. I replaced it with a 36" x 36" ramp so he would have more clearance on either side. I'm still reminding him to check his alignment with the ramp as he's come a little too close with that one too.
We also have a bit of a transition from the driveway into our garage where the ramp from outside to inside is located. I purchased a small (1.5" rise) rubber threshold ramp so that there is not a huge bump when he comes in. It has helped tremendously.
The garage ramp is slightly steeper than ADA specs, but he has no problem getting up it. He does raise his feet slightly.
Overall, he's a pretty good driver, but anyone in a PWC will probably tell you, wall and doorway dings are just part of the game.
In essence, what Karen said is correct. When you let go of the joystick, the brakes are applied.
Here is a more detailed answer.
Almost all wheelchairs are configured so that the brakes are applied when there is no power going to the motors. Whether that is because the wheelchair is powered down or because the joystick is centered does not matter.
The brakes have a disk that is spring loaded to press against a corresponding disk on the motor. In the normal state, that spring is strong enough to apply the force to the disk to keep the motor from turning.
When power is applied to the motors, power is simultaneously applied to the brakes.
Each brake has an electromagnet that becomes magnetized when power is applied. This magnet is strong enough to attract the ferrous disk (essentially, the brake pad) away from the motor, allowing the motor to turn.
When you are slowing down, the brakes are not being applied. Rather, the power being sent to the motors is reduced. In fact, when slowing down, the motors are actually acting like generators. This is a concept call regenerative braking, which can put some power back into the batteries.
None of my wheelchairs actually appears to charge the batteries this way. I think the dissipated energy just becomes heat.
That is probably more than anyone wants or needs to know, but I find it fascinating.
For those P/CALS who are driving with a joystick, just a mention that there are many types of joystick handles out there -- tall, short, thin, fat, flexible, stiff, smooth, ridged, with different textures. They pop on and off for replacement and can be affixed more permanently with hair spray.
If you are not comfortable and secure with the one you have, scout around for one that works for you. You might even want a different one as the seasons change. I have seen big differences in driving just by changing the handle.