Draft control system with closed loop drop/raise rate control
US5320186A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 10, 1991 |
| Grant date | Jun 14, 1994 |
| Priority date | — |
| Expiry date | Sep 10, 2011 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2029
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In an automatic draft control system for positioning a hitch, velocity feedback loop techniques are employed to control the rate of movement of the hitch. When the system is operating in an open loop position control mode, a switch mounted on a tractor fender enables an operator to manually control raising/lowering of the hitch for the purpose of attaching an implement. Hitch position is sensed and a microprocessor calculates the first derivative of the hitch position signal to determine actual hitch velocity. The actual velocity is subtracted from a desired velocity value to obtain a velocity error signal. The error signal is subjected to an integral control algorithm and the integrated value is used to energize raise or lower solenoids controlling a valve which raises or lowers the hitch. When the actual hitch velocity is equal to or greater than the desired hitch velocity, the integrated value is saved. When the next raise/lower sequence is initiated the integrator is reset to the saved value. This eliminates delays in starting hitch motion. The desired velocity value may be derived from the setting of a drop rate potentiometer in which case a drop rate value is added to the int…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.