A robot-assisted surgical system has a user interface operable by a user, a first robotic manipulator having a first surgical instrument, and a second robotic manipulator having a second surgical instrument. The system receives user input in response to movement of the input device by a user and causes the manipulator to move the first surgical instrument in response to the user input, determines a vector defined by the position of the first surgical instrument relative to the second surgical instrument, generates dynamic control signals based on the determined vector, and causes the manipulator to move the second surgical instrument in response to said dynamic control signals.