DC motor control, flipping polarity though processor

[DanielB33]

I have to finish designing a basic circuit to control life cycle testing. Most of my work is on the processor, which I have up and running. I have 5-40V in to a buck boost converter with a steady 12V out to heavy duty solid state relay. When the relay is activated, it works in parallel with a FET to drive our actuators at a given PWM. My question is, how do I use the processor to control flipping polarity??? I need to be able to have someone enter various data though hyper terminal to change duty cycle, etc. With my set up, the actuators will only go one direction. I could easily set this up to happen manually with a mom-off-mom DPDT switch or with 4 solenoids, but I know this is not how things are done a in these applications. What do people normally do?

I assume I use some kind of amazing voltage activated DPDT switch with 2 voltage inputs to toggle poles?

(min current coming out of buck boost converter is 0.5A, relay board needs to run 2 actuators at 12, 24 or 28V each, max 30A load for each actuator.)

Thanks much