Abstract: The straight tracking control system can use a control method to achieve a desired straight motion of a machine with a dual path electronically controlled hydrostatic transmission. In the control method, the first drive system, e.g., the left or right drive system, pump solenoid current can be modified based on first and second drive system velocity feedback when the machine is commanded to move in a straight line path in the forward or reverse direction. A memory latching concept is used to latch the straight tracking factor at the initiation of and during the turn so the same straight tracking factor is used throughout the turn. The straight tracking factor is unlatched at the completion of a turn after a specific time delay and a new straight tracking factor can be calculated. The straight tracking method also utilizes transmission fluid temperature and utilizes additional fluid reserve in order to maintain straight machine movement.

Abstract: A method of managing engine load by adjusting the pump and motor displacements of a dual path electronically controlled hydrostatic transmission utilizes the difference between the reference and actual engine speeds, the temperature of the working fluid for the dual path electronically controlled hydrostatic transmission, the engine governor droop value, the vehicle speed and lookup tables to determine pump and motor command adjustment factors associated with specific engine loading conditions.

Abstract: The straight tracking control system can use a control method to achieve a desired straight motion of a machine with a dual path electronically controlled hydrostatic transmission. In the control method, the first drive system, e.g., the left or right drive system, pump solenoid current can be modified based on first and second drive system velocity feedback when the machine is commanded to move in a straight line path in the forward or reverse direction. A memory latching concept is used to latch the straight tracking factor at the initiation of and during the turn so the same straight tracking factor is used throughout the turn. The straight tracking factor is unlatched at the completion of a turn after a specific time delay and a new straight tracking factor can be calculated. The straight tracking method also utilizes transmission fluid temperature and utilizes additional fluid reserve in order to maintain straight machine movement.

Abstract: A method of managing engine load by adjusting the pump and motor displacements of a dual path electronically controlled hydrostatic transmission utilizes the difference between the reference and actual engine speeds, the temperature of the working fluid for the dual path electronically controlled hydrostatic transmission, the engine governor droop value, the vehicle speed and lookup tables to determine pump and motor command adjustment factors associated with specific engine loading conditions.