Electronicallly controlled ackerman steering

A steering system for use in a vehicle having a first steerable wheel member mounted to the vehicle for pivotal motion about a first axis and a second steerable wheel member mounted to the vehicle for pivotal motion about a second axis, said steering system comprising:

• a tie rod assembly adapted to be mounted between the first and second steerable wheel members to link the first and second steerable wheel members for joint pivotal motion, said tie rod assembly having a length, the length determining the angular relationship of the second steerable wheel member about the second axis dependent upon the angular relationship of the first steerable wheel member about the first axis, said tie rod assembly including structure for adjusting the length of said tie rod assembly;
• a first angle sensor for sensing an angle of the first steerable wheel member about the first axis relative to a reference angle;
• a second angle sensor for sensing an angle of the second steerable wheel member about the second axis relative to a reference angle;
• and
• a controller for adjusting the length of the tie rod assembly dependent upon the angles measured by the first angle sensor and the second angle sensor;
• wherein the tie rod assembly includes a first tie rod portion and a second tie rod portion, said first and second tie rod portions forming a hydraulic cylinder assembly including a piston moveable within a chamber;
• and
• wherein the tie rod assembly further has a spring member mounted to urge the piston against a first end of the chamber.

A steering system for use in a vehicle having a first steerable wheel member mounted to the vehicle for pivotal motion about a first axis and a second steerable wheel member mounted to the vehicle for pivotal motion about a second axis, comprising:

• a tie rod assembly adapted to be mounted between the first and second steerable wheel members to link the first and second steerable wheel members for joint pivotal motion, said tie rod assembly having a length, the length determining the angular relationship of the second steerable wheel member about the second axis dependent upon the angular relationship of the first steerable wheel member about the first axis, said tie rod assembly including structure for adjusting the length of said tie rod assembly;
• a first angle sensor for sensing an angle of the first steerable wheel member about the first axis relative to a reference angle;
• a second angle sensor for sensing an angle of the second steerable wheel member about the second axis relative to a reference angle;
• and
• a controller for adjusting the length of the tie rod assembly dependent upon the angles measured by the first angle sensor and the second angle sensor;
• wherein the controller is adapted to adjust the length of the tie rod assembly dependent upon vehicle wheel base, vehicle track, axle weight and vehicle speed.

A method for maintaining a desired angular relationship between first and second steerable wheel members in a vehicle comprising the steps of:

• measuring an angle of the first steerable wheel member mounted to the vehicle about a first axis relative to a reference angle;
• determining a desired angle of the second steerable wheel member mounted to the vehicle about a second axis relative to the reference angle said desired angle based on the measured angle of the first steerable wheel member, wherein the desired angle allows for correct Ackerman steering;
• and
• adjusting the length of a tie rod assembly linking the first and second steerable wheel members while measuring an angle of the second steerable wheel member about the second axis until the angle of the second steerable wheel member about the second axis is measured to be the desired angle.

A method for maintaining a desired angular relationship between first and second steerable wheel members in a vehicle comprising the steps of:

• measuring an angle of the first steerable wheel member mounted to the vehicle about a first axis relative to a reference angle;
• determining a desired angle of the second steerable wheel member mounted to the vehicle about a second axis relative to the reference angle for the measured angle of the first steerable wheel member;
• and
• adjusting the length of a tie rod assembly linking the first and second steerable wheel members while measuring an angle of the second steerable wheel member about the second axis until the angle of the second steerable wheel member about the second axis is measured to be the desired angle;
• wherein the step of adjusting the length of the tie rod assembly includes adjusting the length of the tie rod assembly dependent upon the vehicle wheel base, vehicle track, axle weight and vehicle speed.