Hi, welcome to the FRA forum. Doesnt sound like a fighting robot to me .

We have all got to start somewhere. If all you want is for it to reverse when it hits something, turn and carry on then its quite simple. I did a similar project way back at collage but used ultrasonic sensors instead of microswitches. It simply turned left for a set time and then carried on. This used modified servos for drive. If you are planning to use the servos as drive motors then you dont need any additional circuit (H-Bridge) to drive the motor but you do need to send servo pulses to it. Thinking back to how I did it we sent the servos a 200Hz square wave for forward and 400Hz squarewave for backward. Not what the servos want but it did reverse the motor direction.

If you do want to make the whole circuit then one of the simplest ways i can think of is to have the motors on all the time (on/off switch)and when a wisker is hit it, it will switch 2 relays to reverse both motors direction and 2 555s can be used to time how long the relays are on. If one relay is on for 1 second and the other is on for 2 seconds then after 1 second it will start to turn (as only one motor has started going forwards again) and then after 2 seconds the other motor will reverse. The times can be adjusted for a specific turn angle.

Good luck