초록 ▼

A tractor includes a hitch for pulling a ground-engaging implement. A hydraulic cylinder is extendable and retractable to lower and raise the implement. A control system senses operating parameters, including wheel slip, engine speed, draft force and implement or rackshaft position. Error signals de

A tractor includes a hitch for pulling a ground-engaging implement. A hydraulic cylinder is extendable and retractable to lower and raise the implement. A control system senses operating parameters, including wheel slip, engine speed, draft force and implement or rackshaft position. Error signals derived from the sensed wheel slip, engine speed and draft force are combined into a composite or combined error signal. The larger of the combined error signal, or a separately determined position error signal, is selected and converted to a pulsewidth modulated valve control signal which is applied to a control valve which then actuates the cylinder to move the implement to reduce the magnitude of the selected error signal.

대표청구항 ▼

In a vehicle having connecting means for attaching a ground-penetrating implement thereto and actuating means for raising and lowering the implement to vary the ground penetration thereof in response to signals applied to an input thereof: sensing means for sensing an operating parameter of a machin

In a vehicle having connecting means for attaching a ground-penetrating implement thereto and actuating means for raising and lowering the implement to vary the ground penetration thereof in response to signals applied to an input thereof: sensing means for sensing an operating parameter of a machine system comprising the vehicle, the connecting means and the implement, and for generating a parameter signal representative thereof; set point means for deriving a parameter set point signal from the parameter signal; difference means for generating a parameter error signal representing a difference between the parameter signal and the parameter set point signal; and means for converting the parameter error signal to a control signal and for applying the control signal to the input of the actuating means, the actuating means being adapted to move the implement in response to the control signal.