Method and apparatus for controlling a tractor/implement combination

A tractor/implement combination comprising:

• a first sensor for detecting the tractor engine flywheel torque and generating a signal indicative thereof;
• an actuator for selectively engaging the implement with and disengaging it from a surface;
• a second sensor for detecting the selected transmission ratio of the tractor and generating a signal indicative thereof;
• a memory;
• and
• a programmed processor, said tractor/implement combination being operable, under control of the processor
• (i) to detect the torque at the tractor engine flywheel, and generate a signal indicative thereof while said tractor/implement combination advances across a surface with a first tractor transmission ratio selected and the implement disengaged from the surface;
• (ii) to store in said memory the value of the signal as a calibration value associated with the selection of the first transmission ratio;
• (iii) to shift the tractor transmission to a new ratio and repeat steps (i) and (ii) while the tractor/implement combination advances with said new ratio to store a new calibration value associated with the new ratio;
• (iv) to shift the tractor transmission a plurality of times to store a plurality of calibration values each said calibration value respectively associated with a tractor transmission ratio;
• (v) to detect the torque at the tractor engine flywheel and generate an uncorrected torque signal indicative thereof while the tractor/implement advances across the surface with one of transmission ratios selected, and with the implement engaging the surface;
• (vi) to subtract the stored calibration value associated with the selected said transmission ratio from the value of the uncorrected signal to generate a corrected torque signal indicative of the draft of the implement;
• and
• (vii) to carry out a control operation dependant upon the value of the corrected torque signal.

A method of controlling tractor wheelslip in a tractor/implement combination in which a tractor three point hitch at least partly supports the implement and in which the implement is semi-mounted by means of a mounting remote from the three point hitch, the method comprising the steps of:

• (i) setting a wheelslip limit corresponding to a desired maximum degree of wheelslip;
• (ii) detecting an instantaneously prevailing degree of wheelslip;
• (iii) raising a first part of the implement by raising the three point hitch when the detected degree of wheelslip equals or exceeds the wheelslip limit;
• and
• (iv) raising a second part of the implement relative to the remote mounting until the detected degree of wheelslip is less than the wheelslip limit.

A tractor/implement combination wherein a tractor three point hitch supports part of the implement;

• and wherein the implement is semi-mounted by means of a mounting remote from the three point hitch, comprising:
• a wheelslip detector;
• an actuator for raising and lowering the three point hitch;
• an actuator for raising and lowering a part of the implement relative to the remote mounting;
• a processor capable of generating adjustment signals for causing adjustment of the hitch height and the actuator height;
• and
• a memory capable of storing therein a wheelslip limit value, the processor being programmed to optimize wheelslip by adjusting the hitch height and the actuator height.