To understand how the robotized gearbox works, it is necessary to imagine the usual “mechanics”. The only difference between them lies in the fact that by closing / opening the clutch and gear selection in a “robot” are made by servo – actuators. Most often it is a stepping motor with gear and actuator, but there are also hydraulic actuators. They are managed by the electronic unit. By command of electronics for switching the first servo clutch, the second one moves the synchronizers, including the right gear. Then first one slowly releases the clutch. That’s all.
It would seem ideally, circuit is simple, highly efficient, and less than a torque converter, fuel consumption. But there is a catch: in order to avoid jerks and not mock-clutch during switching transmission, “robot” permanently severs the connection between the engine and the wheels, which is why during the dispersal there are unpleasant failures, get rid of that is only one way – to reduce the time of switching.
If the angular sensors of wheel speed are recorded slipping, the system depending on the settings can reduce the supply of fuel and reduce the engine torque, or brake the slip wheel, or do everything simultaneously. A system is particularly useful on slippery surfaces. It also can prevent wheel spin during the throttle in the corners, thus not allowing develop a skid of the rear axle on the rear wheel drive cars and demolished of the front one on the front wheel.
The system has a positive effect on the stability and safety of the vehicle, especially on slippery surfaces, preventing driver excessive pressing the gas to cause a critical situation. But it can do a disservice traveling through deep snow, sand or mud, “choking” the engine just at the moment when the car needs the maximum gas to a slipping out of the unstable surface. Therefore, to drive on the sand or snow (at low speeds) Traction Control is disabled as needed in advance.