Patent ID: 6129170
Filing Date: 2000-10-10
Classification: B62D

Abstract:
An articulated steered mobile machine steering system, comprising:first, second and third machine sections, said second machine section being pivotally connected to said first machine section and said third machine section being pivotally connected to said second machine section;a first pair of fluid operated steering jacks connected between said first and second machine sections, said first pair of fluid operated steering jacks being extensibly movable to pivot said first and second machine sections relative to each other;a second pair of fluid operated steering jacks connected between said second and third machine sections, said second pair of steering jacks being extensibly movable to pivot said second and third pivotal machine sections relative to each other;a first electrically operated control valve connected to the first pair of fluid operated steering jacks and actuatable to control a passing of fluid flow to extensibly move the first pair of fluid operated steering jacks;a second electrically operated control valve connected to the second pair of fluid operated steering jacks and actuatable to control a passing of fluid flow to extensibly move the second pair of fluid operated steering jacks;a first sensor connected to said machine, said first sensor sensing an actual relative steering angle position of the first and second machine sections and delivering a corresponding first actual steering angle signal;a second sensor connected to said machine, said second sensor sensing an actual relative steering angle position of the second and third machine sections and delivering a corresponding second actual steering angle signal;a controller connected in communication with the first and second sensors and said first and second electrically operated control valves, said controller receiving said first and second actual steering angle signals, determining a desired relative steering angle position of the second and third sections based on the first actual steering angle signal, and delivering a correcting steering angle signal in response to a difference between the desired and actual relative steering angles of the second and third sections; andan automatic-manual mode switch connected to said controller and being movable between an automatic mode position at which the correcting steering angle signal is delivered to said second electrically operated control valve and a manual mode position at which the correcting steering angle signal is blocked from said second electrically operated control valve, said second electrically operated control valve being actuatable in response to receiving said correcting steering angle signal to pass of fluid flow to said second pair of steering jacks and relatively pivotally move the second and third machine sections.