System and method for collision avoidance using virtual boundaries

A method of collision avoidance, the method comprising:

• determining, by a control unit, first positions of a plurality of first joints of a first repositionable arm, a first instrument being mounted to a distal end of the first repositionable arm;
• determining, by the control unit, second positions of a plurality of second joints of a second repositionable arm, a second instrument being mounted to a distal end of the second repositionable arm;
• determining, by the control unit, positions of a plurality of first virtual boundaries around the first repositionable arm using the first positions and a first virtual model of the first repositionable arm;
• determining, by the control unit, positions of a plurality of second virtual boundaries around the second repositionable arm using the second positions and a second virtual model of the second repositionable arm;
• determining, by the control unit, a first overlap between a first one of the first virtual boundaries and a first one of the second virtual boundaries;
• determining, by the control unit, a first overlap force on the first and second repositionable arms due to the first overlap;
• mapping, by the control unit, the first overlap force to first virtual torques on first joints of the plurality of first joints proximal to a first overlap position of the first overlap;
• determining, by the control unit, a first tip force on a distal end of the first instrument based on the first virtual torques;
• applying the first tip force as a first feedback force on the first instrument and the first repositionable arm;
• and
• applying the first tip force as a first haptic feedback force to a first input control configured to provide movement commands for the first instrument.

A computer-assisted manipulation device comprising:

• a repositionable arm having a plurality of joints, a plurality of links, and a distal end configured to support an instrument;
• an input control configured to provide movement commands for the instrument;
• and
• a control unit comprising one or more processors, the control unit coupled to the repositionable arm and the input control, wherein the control unit is configured to:
• determine joint positions of the plurality of joints;
• use a virtual model of the repositionable arm and the joint positions to determine a plurality of virtual boundaries, the plurality of virtual boundaries around the repositionable arm or the instrument;
• determine an object virtual boundary around an object;
• determine an overlap between the object virtual boundary and a virtual boundary of the plurality of virtual boundaries;
• determine an overlap force on the repositionable arm due to the overlap;
• map the overlap force to a virtual torque on a joint of the plurality of joints;
• determine a tip force on a distal end of the instrument using the virtual torque;
• and
• apply the tip force as a feedback force on the instrument and the repositionable arm.