command signal and a scheduled yaw signal at a summing node 102 the scheduled yaw signal may be read from a stored program which is previously established in the computer 12 as for example a function of the geometry of the cutting path rather than a variable parameter such as the lateral forces detected by the sensor 76 other scheduled yaw signals and the method of obtaining such signals are described and illustrated in greater detail in the referenced copending applications ser nos 790 035 and 789 848 the signals combined at the summing node 102 form a single machine command signal that is transmitted to the driver 72 to operate the u03b8 drive motor 44 and orient the blade it should be understood that in most circumstances when scheduled yaw is employed in combination with yaw derived from blade forces the scheduled yaw program if properly selected should provide the primary corrections for reducing blade loading and more limited and finer corrections are produced by the feedback signals from the load sensor thus the closed loop control system may be used both alone and in conjunction with other correction systems to improve cutting accuracy the yaw signal from the correction circuit 100 is also fed to a yaw rate circuit 104 the rate of change of yaw is derived by the circuit 104 and is transmitted to the displacement logic circuit 60 in place of the feedback signal for the purpose of reducing the feed rate of the cutting blade along the cutting path thus the displacement command signals from the circuits 60 reduce the feed rate of the cutting blade whenever yaw corrections are made and the reduction is proportional to the rate.