To　investigate　the　unknown　(uncertain)　tire　steering　resistance　moment　and　model　uncertainties　in　a　multi-axle　vehicle　electro-hydraulic　power　steering　system　(EHPSS),　including　the　steering　mechanisms,　valve-controlled　double　hydraulic　actuators,　and　heavy-duty　tires,　an　adaptive　robust　control　algorithm　is　developed　to　estimate　the　tire　steering　resistance　moment　online　and　compensate　for　the　model　uncertainties　of　EHPSS.　The　proposed　control　strategy　consists　of　an　adaptive　control　law　and　a　robust　controller　which　are　based　on　a　Lyapunov　function.　The　adaptive　control　law　is　employed　to　update　estimated　values　of　the　(unknown)　tire　steering　resistance　moment　and　parameter　uncertainties　in　the　EHPSS,　whereas　complicated　nonlinearities　are　addressed　by　the　robust　controller.　All　adaptive　laws　of　the　EHPSS　and　controller,　which　can　impede　parametric　uncertainties　and　stabilize　the　EHPSS,　are　synthesized　by　backstepping　techniques.　The　comparative　simulation　results　demonstrate　that　the　proposed　adaptive　robust　control　scheme　can　achieve　the　desired　performance　for　feasible　tracking　trajectories　despite　the　existence　of　an　uncertain　tire　steering　resistance　moment　and　external　disturbance　in　the　EHPSS.