Ramps [tour 14]

Acceleration Ramp

Even if the throttle is applied sharply, the controller must accelerate the motor smoothly, without a jerk, so an ‘acceleration ramp’ is built into all controllers. This may be a an adjustable ramp or a fixed ramp – although even a fixed ramp can be altered by changing a component value in the controller (usually a factory modification). If the ramp is too fast, the wheels might spin or, for example, a badly balanced golf buggy might tip over backwards – especially on a hill! So the acceleration ramp may need to be altered to suit the machine.

Deceleration Ramp

Similarly when the throttle is released sharply, a controller with regenerative braking must decelerate the machine smoothly – this is controlled by the deceleration ramp. Too fast a ramp and the machine will skid to a stop.

In 4QD’s controllers both these ramps are very smooth and very linear.

Controllers without regenerative braking may require a ramp depending on the power-down state. If the controller shorts out the motor at zero speed this will cause a sudden braking unless power-down is delayed to be longer than the braking time which is determined solely by the motors and mechanics, not by the controller.

Adjustable Ramps

The rate at which the machine needs to accelerate (or decelerate) will depend upon the machine and how fast it is, so the reversing controllers have adjustable ramps. The adjustment is by two small (screwdriver operated) adjustments, one for accel, one for decel or by programming.

CR Ramp

The 2QD series do not have a linear ramp but a simple system controlled by a fixed resistor and capacitor (hence ‘CR’).


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