Hydromechanical transmission with hydrostatic assembly and hydrostatic assembly control method

A transmission, comprising:

• a hydrostatic assembly including a variable displacement hydraulic pump and a variable displacement hydraulic motor;
• a multi-speed gearbox coupled to the hydrostatic assembly;
• and
• a controller including instructions that when executed cause the controller to:
• adjust a displacement set-point of the variable displacement hydraulic motor based on a kinematic constraint and/or a torque constraint of the hydrostatic assembly;
• wherein the torque constraint is determined based a differential pressure and a target differential pressure of the hydrostatic assembly.

A method for operation of a hydromechanical variable transmission (HVT), comprising:

• adjusting a displacement set-point of a variable displacement hydraulic motor in a hydrostatic assembly based on a kinematic constraint and a torque constraint of the hydrostatic assembly;
• wherein the HVT includes:
• the hydrostatic assembly that includes the variable displacement hydraulic motor that is hydraulically coupled in parallel with a variable displacement hydraulic pump;
• and
• a multi-speed gearbox mechanically coupled to the hydrostatic assembly and including one or more clutches.