Hitch positioning with slip override control and calibrated wheel speed for determining slip
US5190111A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 1991 |
| Grant date | Mar 2, 1993 |
| Priority date | — |
| Expiry date | Jun 3, 2011 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60D1/42
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An automatic draft control for controlling the position of a tractor-mounted hitch includes a slip override circuit responsive to a wheel signal for modifying a hitch position command so that hitch draft is reduced by raising the hitch when the degree of tractor wheel slip exceeds a threshold value. The slip is determined by measuring theoretical (no-slip) ground speed with a sensor which senses the rate of rotation of the tractor rear axle, and measuring true ground speed with a radar unit mounted on one side of the tractor. Because the radar unit does not indicate the speed of the center line of the tractor as it turns, the slip signal is prevented from modifying the hitch position command if the hitch is raised since the hitch is usually raised when turning and there is no need to modify the position command with the slip signal when the hitch is raised. The true ground speed is automatically and repeatedly divided by the rate of rotation of the tractor rear axle when conditions are such that wheel slippage is unlikely. The multiple divisions produce plural indications of a correction factor. These indications are filtered to obtain a correction factor which accounts for variati…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.