Coordinated Boom Control System for Rough Terrain Forklifts

Digital Electronics, Sensors, and Electro-hydraulic Control Valves have been combined to produce a system which automatically coordinates the variable reach boom on rough terrain forklifts to produce true Horizontal or Vertical Motion of the forks. The system results in fast and safe load placement and removal of forks from loads in high places with ease. Motion can be commanded by the operator to be horizontal or vertical. Boom Length sensors and Boom Angle sensors provide information to the micro-controller in order to control the motion of the boom which results in the desired horizontal or vertical motion regardless of slope of the terrain on which the vehicle is placed. Input of Engine Speed also ensures that the maximum flow commanded from the valves does not exceed flow available from the hydraulic pump resulting in smooth and fast coordinated boom motion at any engine speed. This paper describes the control system including the sensors, command joystick, and controller. The implementation of the control logic and trigonometry calculations will also be discussed.