Drive force control system

1. A drive unit, comprising:

a first motor connected to a right drive wheel;

a second motor connected to a left drive wheel;

a clutch that allows a torque transmission between the first motor and the second motor, in which a torque transmitting capacity is variable;

an electrical power source that supplies electric power to the first motor and the second motor; and

a controller that controls output torques of the first motor and the second motor and a torque transmitting capacity of the clutch, the controller being configured to:

calculate a total required torque of the drive unit;

obtain a plurality of combinations of a first interim torque of the first motor and a second interim torque of the second motor to achieve the total required torque of the drive unit;

select a combination of the first interim torque of the first motor and the second interim torque of the second motor to minimize an output electric power of the electrical power source;

output the first interim torque of the first motor and the second interim torque of the second motor based on the selected combination;

calculate a first required torque of the right drive wheel and a second required torque of the left drive wheel;

when the first required torque is larger than the second required torque, calculate the torque transmitting capacity of the clutch by subtracting the first required torque from the first interim torque of the selected combination;

when the second required torque is larger than the first required torque, calculate the torque transmitting capacity of the clutch by subtracting the second required torque from the second interim torque of the selected combination; and

control the clutch in such a manner as to achieve the calculated torque transmitting capacity.