A control system for a grading machine includes a circle angle sensor coupled to a circle. The circle is coupled to and supports a grading blade, and the circle angle sensor is configured to measure an angular position of the circle. The control system also includes a blade load sensor configured to measure a load on the grading blade. The control system also includes a circle drive system including a circle drive motor and a controller. The circle drive motor is configured to engage with and rotate the circle around a circle axis, and the controller is configured to control the rotation of the circle under a circle rotation command by monitoring the angular position of the circle and the load on the grading blade.