A robotic system comprising: an input device (108, 109); a manipulator configured to manipulate an articulated instrument; and a processor configured to: generate a commanded pose of the articulated instrument in response to operator manipulation of the input device (108, 109), modify the commanded pose by applying a virtual barrier as a constraint to prevent the articulated instrument from being commanded to move beyond the virtual barrier in a first direction until at least a portion of the articulated instrument which is closest to, but has not yet encountered the virtual barrier conforms with a first preferred pose; generate a stream of modulation coefficients by determining a difference between the commanded pose and the modified commanded pose, projecting the difference along the first direction, and binary coding the projected difference by setting a current modulation coefficient to a first value if the projected difference is greater than a threshold value and setting the current modulation coefficient to a second value if the projected difference is less than or equal to the threshold value; generate a first activation signal by passing the stream of modulation coefficients through a low-pass filter; generate first force commands for a plurality of degrees of freedom of the input device so as to be indicative of a difference between the first preferred pose and the commanded pose; and phase in an application of the first force commands on the plurality of degrees of freedom of the input device according to the first activation signal. an input device (108, 109); a manipulator configured to manipulate an articulated instrument; and a processor configured to: generate a commanded pose of the articulated instrument in response to operator manipulation of the input device (108, 109), modify the commanded pose by applying a virtual barrier as a constraint to prevent the articulated instrument from being commanded to move beyond the virtual barrier in a first direction until at least a portion of the articulated instrument which is closest to, but has not yet encountered the virtual barrier conforms with a first preferred pose; generate a stream of modulation coefficients by determining a difference between the commanded pose and the modified commanded pose, projecting the difference along the first direction, and binary coding the projected difference by setting a current modulation coefficient to a first value if the projected difference is greater than a threshold value and setting the current modulation coefficient to a second value if the projected difference is less than or equal to the threshold value; generate a first activation signal by passing the stream of modulation coefficients through a low-pass filter; generate first force commands for a plurality of degrees of freedom of the input device so as to be indicative of a difference between the first preferred pose and the commanded pose; and phase in an application of the first force commands on the plurality of degrees of freedom of the input device according to the first activation signal. generate a commanded pose of the articulated instrument in response to operator manipulation of the input device (108, 109), modify the commanded pose by applying a virtual barrier as a constraint to prevent the articulated instrument from being commanded to move beyond the virtual barrier in a first direction until at least a portion of the articulated instrument which is closest to, but has not yet encountered the virtual barrier conforms with a first preferred pose; generate a stream of modulation coefficients by determining a difference between the commanded pose and the modified commanded pose, projecting the difference along the first direction, and binary coding the projected difference by setting a current modulation coefficient to a first value if the projected difference is greater than a threshold value and setting the current modulation coefficient to a second value if the projected difference is less than or equal to the threshold value; generate a first activation signal by passing the stream of modulation coefficients through a low-pass filter; generate first force commands for a plurality of degrees of freedom of the input device so as to be indicative of a difference between the first preferred pose and the commanded pose; and phase in an application of the first force commands on the plurality of degrees of freedom of the input device according to the first activation signal.