초록

An automatic control system for passive, towed implements is described. The system provides a strategy for optimal control of a towed implement using a nudge input to an autopilot-controlled tractor. Implement path-tracking error, as measured by a GNSS receiver, is consistently corrected to zero.

대표청구항 ▼

1. A method for guiding a passive implement along a desired path comprising: providing a tractor guided by an autopilot having a nudge input;introducing a test input to the tractor autopilot;providing a GNSS receiver fixed to the passive implement;towing the passive implement behind the tractor via

1. A method for guiding a passive implement along a desired path comprising: providing a tractor guided by an autopilot having a nudge input;introducing a test input to the tractor autopilot;providing a GNSS receiver fixed to the passive implement;towing the passive implement behind the tractor via a hitch;using a model of the tractor-hitch-implement system to provide feedback to a control system that provides nudge inputs to the autopilot-controlled tractor and to the model; wherein, the model estimates the immediate passive implement offset from the path;tractor, hitch and implement elements within the model are arranged such that nudge inputs from the control system are applied to the implement element directly;the tractor element of the model includes information obtained from measurements of the motion of the tractor in response to the test input; and,the control system nudge inputs cause the difference between the actual implement path and the desired path to be minimized. 2. The method of claim 1 wherein the test input is a step offset and the information obtained from measurements of the motion of the tractor is the time, t1/2, required for the tractor to achieve half the step offset. 3. The method of claim 1 wherein the test input is a step, a pulse, or a sinusoid and the information obtained from measurements of the motion of the tractor is a set of parameters that best fit the motion to a transfer function. 4. The method of claim 1 wherein the test input is a pseudorandom sequence and measurements of the motion of the tractor are cross-correlated with the pseudorandom sequence to determine a tractor response function. 5. The method of claim 1 wherein measurements of the motion of the tractor are obtained using a GNSS receiver fixed to the tractor. 6. The method of claim 1 wherein the hitch element of the model includes the distance from the hitch to the midpoint of the tractor's rear axle. 7. The method of claim 1 wherein the implement element of the model includes the distance from the implement's control point to the hitch. 8. The method of claim 1 wherein the GNSS receiver is a GPS receiver employing SBAS corrections. 9. The method of claim 8 wherein the SBAS corrections are obtained from the FAA WAAS. 10. The method of claim 1 wherein the GNSS receiver is a GPS receiver employing RTK positioning.