My bad the motors currently operates at a maxium of 30VDC and consumes 250mA. The motor takes voltage from 0-30VDC. The motor controls the claw and the more voltage the stronger the claw grips. So, I would like to increase the adjustable voltage range to 0-50VDC.

Then you can use OPA544, like Raghunathan suggested. You can have it running with asymmetric supply voltage. Then, a slight increase of positive supply voltage is possible.

Use good cooling and connect Zobel network at output, as well as free wheeling diodes. Zobel network will also act as snubber.

Kai