I have a field filled with obstacles, I know where they are located, and I know the robot's position. Using a path-finding algorithm, I calculate a path for the robot to follow.

Now my problem is, I am guiding the robot from grid to grid but this creates a not-so-smooth motion. I start at A, turn the nose to point B, move straight until I reach point B, rinse and repeat until the final point is reached.

So my question is: What kind of techniques are used for navigating in such an environment so that I get a smooth motion?

The robot has two wheels and two motors. I change the direction of the motor by turning the motors in reverse.

EDIT: I can vary the speed of the motors basically the robot is an arduino plus ardumoto, I can supply values between 0-255 to the motors on either direction.