A hybrid system includes a transmission control module, a power source, a transmission, and a drive train. The transmission control module partially operates the hybrid system and receives operating information from various components of the system, calculates power losses in the drive train, and calculates the driving torque needed to reach a target power profile determined from a driver's input.

A required traction force determining part is configured to determine a required traction force corresponding to an output rotational speed based on a required traction force characteristic. A command torque determining part is configured to determine a command torque to be transmitted to a motor to obtain the required traction force. An opposite movement determining part is configured to determine that a vehicle is oppositely moving when a vehicle speed becomes a predetermined speed threshold or greater in a direction opposite to a moving direction corresponding to a position of a forward/rearward movement operating member. A traction force assisting part is configured to perform a traction force assisting control when it is determined that the vehicle is oppositely moving. The traction force assisting part is configured to increase the required traction force in the moving direction corresponding to the position of the forward/rearward movement operating member.