Electrohydraulic controls have become more standard in machine operator stations in an attempt to reduce operator effort and improve ergonomics. Electrohydraulic systems typically employ some type of commanded electronic signal to activate hydraulic functions. Traditional machine operators are accustomed to mechanically actuated hydraulic valves in which a physical linkage connects the control lever to the hydraulic control valve. Due to the direct acting linkage, standard hydraulic controls inherently provide a tactile feedback that the operator can use to be more accurate and precise in his/her machine operation. This sensory feedback may be largely attributed to the variable flow forces created by the hydraulic fluid acting on the hydraulic control valve at various valve spool positions.
Machine operators that are familiar with operating equipment that have mechanically actuated hydraulic valves indicate difficulty adjusting to electrohydraulic controls largely because of the lack of feedback from the control levers. When actuating a hydraulic function with an electronic joystick, it is very difficult to discern between a very small operator command and a large operator command because no sensory stimulus is produced other than lever effort and position required to adjust the lever. As a result, operators indicate a heavier reliance upon their visual senses to operate electrohydraulic controls.