I have four servos connected to an arduiono uno and I cannot control them
As others have said, the Arduino cannot drive 4 servos - my experience is that it can have problems powering one if you try to move it too often due to the voltage drop caused by the high current consumption.  When you move a servo the power consumption rises considerably.  A large (220uF or more) capacitor near he servo can help, but even so, by far the best option is to supply the servos from a separate supply.

If the Uno resets when you try to move the servos (especially multiple times per second) then the power supply is most likely your culprit.