Steering system with magnetic torque overlay lash compensation
AssigneeSteering Solutions IP Holding Corporation
InventorJoel E. Birsching
Life of this patent
Estimating the term…
Abstract
Technical solutions for compensating for lash in a steering system are described. An example method includes determining a rack pressure value based on a driver torque value and a differential pressure across a rack of the steering system. The method also includes determining a compensation friction value based on a position of a handwheel of the steering system and a speed of a vehicle equipped with the steering system. The method also includes computing a pressure value based on the rack pressure value and the compensation friction value. The method also includes generating a torque command using the pressure value, the torque command being added to the driver assist torque for the steering system.
Claims15
A method for compensating for lash in a steering system, the method comprising:
- determining a rack pressure value based on a driver torque value and a differential pressure across a rack of the steering system;
- determining a center friction value based on a difference between a first pressure value and a second pressure value, the first pressure value being a pressure measurement across a first cavity in a ball steering gear of the steering system, and the second pressure value being a pressure across a second cavity in the ball steering gear;
- computing a pressure value based on the rack pressure value and the center friction value, wherein computing the pressure value further includes:
- determining a dynamic pressure value based on a speed of the handwheel of the steering system, wherein determining the dynamic pressure value comprises multiplying the speed of the handwheel by a predetermined scaling factor;
- and
- adding a static pressure value and the dynamic pressure value to compute the pressure value;
- and
- generating a torque command using the pressure value, the torque command being added to the driver assist torque for the steering system.
A steering system comprising:
- a ball steering gear that comprises a first cavity and a second cavity;
- and
- a control module configured to compensate for lash in the steering system by performing a method comprising:
- determining a rack pressure value based on a driver torque value and a differential pressure across a rack of the steering system;
- determining a center friction value based on a difference between a first pressure value and a second pressure value, the first pressure value being a pressure measurement across the first cavity, and the second pressure value being a pressure across the second cavity;
- computing a pressure value based on the rack pressure value and the center friction value, wherein computing the pressure value further comprises:
- determining a static pressure value based on the rack pressure value;
- determining a dynamic pressure value based on a speed of the handwheel of the steering system, wherein determining the dynamic pressure value comprises multiplying the speed of the handwheel by a predetermined scaling factor;
- and
- adding the static pressure value and the dynamic pressure value to compute the pressure value;
- and
- generating a torque command using the pressure value, the torque command being added to the driver assist torque for the steering system.
A computer program product comprising a memory device having computer executable instructions stored therein, the computer executable instructions when executed by a processing unit cause the processing unit to perform a method to compensate for lash in a steering system, the method comprising:
- determining a rack pressure value based on a driver torque value and a differential pressure across a rack of the steering system;
- determining a center friction value based on a difference between a first pressure value and a second pressure value, the first pressure value being a pressure measurement across a first cavity in a ball steering gear of the steering system, and the second pressure value being a pressure across a second cavity in the ball steering gear;
- determining a static pressure value based on the rack pressure value;
- determining a dynamic pressure value by multiplying a speed of the handwheel by a predetermined scaling factor;
- computing a pressure value by adding the static pressure value and the dynamic pressure value;
- and
- generating a torque command using the pressure value, the torque command being added to the driver assist torque for the steering system.
Dependencies are inferred from the claim text.