Variable electric transmission system and method

A method of controlling a transmission system, the transmission system comprising a left gear system coupled to a first rotary input and a second rotary input;

• a right gear system coupled to the first rotary input and a third rotary input;
• a left rotary output coupled to the left gear system;
• and a right rotary output coupled to the right gear system, wherein during operation a speed of the left rotary output is independent of a speed of the right rotary output, the method comprising:
• receiving a desired left rotary output speed;
• determining a constant speed line required to produce the desired left rotary output speed using a general speed line equation;
• measuring an actual output speed of the left rotary output of the transmission system;
• comparing the desired left rotary output speed to the actual output speed of the left rotary output of the transmission system;
• adjusting the first rotary input of the transmission system and the second rotary input of the transmission system until the desired left rotary output speed matches the actual output speed of the left rotary output of the transmission system;
• and
• optimizing the first rotary input of the transmission system and the second rotary input of the transmission system to a most efficient Speed Pair for the desired left rotary output based on an efficiency map.