Closed feedback control for electrosurgical device
A robotic surgical system including a control circuit configured to: (i) generate an energy control signal to deliver an electrosurgical energy signal to a first electrode and a second electrode, (ii) measure a current supplied and a voltage applied to the first and second electrodes, (iii) calculate impedance based on the measured current and voltage, (iv) compare the calculated impedance to a predetermined impedance level, (v) generate a subsequent energy control signal to deliver a subsequent electrosurgical energy signal to the first and second electrodes, when the calculated impedance is less than the predetermined impedance level, by adjusting at least one energy signal characteristic between the delivered electrosurgical energy signal and the subsequent electrosurgical energy signal based on the calculated impedance, and (vi) generate a drive control signal to activate a blade when the calculated impedance is greater than or equal to the predetermined impedance level.
1. A robotic surgical system, comprising:
a control circuit configured to:
generate a first energy control signal to deliver a first electrosurgical energy signal for energizing a first electrode of a first end effector jaw and a second electrode of a second end effector jaw;
measure a current supplied to the first and second electrodes;
measure a voltage applied to the first and second electrodes;
calculate impedance based on the measured current and the measured voltage;
compare the calculated impedance to a predetermined tissue impedance level;
generate a second energy control signal to deliver a second electrosurgical energy signal to the first and second electrodes when the calculated impedance is less than the predetermined tissue impedance level, wherein the first electrosurgical energy signal and the second electrosurgical energy signal are defined by at least one energy signal characteristic, and wherein generating the second energy control signal to deliver the second electrosurgical energy signal comprises adjusting the at least one energy signal characteristic between the first electrosurgical energy signal and the second electrosurgical energy signal based on the calculated impedance; and
generate a drive control signal to advance a blade configured to translate along channels defined in the first and second end effector jaws when the calculated impedance is greater than or equal to the predetermined tissue impedance level;
wherein the control circuit comprises a processor configured to execute a step function algorithm to adjust the at least one energy signal characteristic, wherein the processor executes the step function algorithm to:
compare the calculated impedance to a plurality of impedance thresholds less than the predetermined tissue impedance level, wherein each of the plurality of impedance thresholds is correlated to a tissue sealing state;
determine that the calculated impedance has crossed an impedance threshold of the plurality of impedance thresholds; and
modify the at least one energy signal characteristic of the first electrosurgical energy signal by a step to establish the second electrosurgical energy signal for delivery to the first and second electrodes.
2. The robotic surgical system of claim 1 , wherein the calculated impedance is a ratio of the measured voltage to the measured current associated with the first electrosurgical energy signal.
3. The robotic surgical system of claim 1 , wherein the predetermined tissue impedance level is indicative of tissue located between the first and second end effector jaws being in a sealed state.
4. The robotic surgical system of claim 1 , wherein the control circuit comprises:
a current sense circuit configured to measure the current supplied to the first and second electrodes by the first electrosurgical energy signal; and
a voltage sense circuit configured to measure the voltage applied to the first and second electrodes by the first electrosurgical energy signal.
5. The robotic surgical system of claim 1 , wherein the at least one energy signal characteristic adjusted between the first electrosurgical energy signal and the second electrosurgical energy signal comprises a current, a voltage, or a frequency.
6. The robotic surgical system of claim 1 , wherein the blade is coupled to a motor, and wherein the drive control signal is configured to deliver a drive signal to the motor to advance the blade.
7. The robotic surgical system of claim 1 , wherein modifying the at least one energy signal characteristic of the first electrosurgical energy signal comprises stepping up at least one of a current, a voltage, or a frequency by a predetermined increment, or stepping down at least one of the current, the voltage, or the frequency by a predetermined decrement.
8. The robotic surgical system of claim 1 , wherein modifying the at least one energy signal characteristic of the first electrosurgical energy signal comprises stepping up at least one of a current, a voltage, or a frequency by an adaptively increased step, or stepping down at least one of the current, the voltage, or the frequency by an adaptively decreased step.
9. The robotic surgical system of claim 1 , wherein the first electrosurgical energy signal is delivered to the first and second electrodes for a variable period of time.
10. The robotic surgical system of claim 1 , wherein the control circuit is positioned within an electrosurgical instrument comprising the first and second electrodes.
11. The robotic surgical system of claim 1 , wherein the control circuit is positioned within a surgical robot of the robotic surgical system or a controller communicatively coupled to the surgical robot.
12. A robotic surgical system, comprising:
a surgical instrument, comprising:
an end effector, comprising:
a first jaw member including a first electrode;
a second jaw member including a second electrode, wherein the first electrode and the second electrode are configured to receive a plurality of electrosurgical energy signals; and
a blade configured to reciprocate within the first jaw member and the second jaw member along a longitudinal axis; and
a control circuit configured to:
generate a first control signal to deliver a first electrosurgical energy signal to the first electrode and the second electrode;
measure a first current supplied to the first electrode and the second electrode by the first electrosurgical energy signal;
measure a first voltage applied to the first electrode and the second electrode by the first electrosurgical energy signal;
calculate a first impedance based on the measured first current and the measured first voltage;
compare the calculated first impedance to a predetermined impedance level, wherein the predetermined impedance level is indicative of tissue being in a sealed state;
generate a second control signal to deliver a second electrosurgical energy signal to the first electrode and the second electrode when the calculated first impedance is less than the predetermined impedance level, wherein the first electrosurgical energy signal and the second electrosurgical energy signal are defined by at least one energy signal characteristic, and wherein generating the second control signal to deliver the second electrosurgical energy signal comprises adjusting the at least one energy signal characteristic between the delivered first electrosurgical energy signal and the second electrosurgical energy signal based on the calculated first impedance;
measure a second current supplied to the first electrode and the second electrode by the second electrosurgical energy signal;
measure a second voltage applied to the first electrode and the second electrode by the second electrosurgical energy signal;
calculate a second impedance based on the measured second current and the measured second voltage;
compare the calculated second impedance to the predetermined impedance level; and
generate a drive control signal to reciprocate the blade within the first jaw member and the second jaw member along the longitudinal axis when the calculated second impedance is greater than or equal to the predetermined impedance level;
wherein the control circuit comprises a processor configured to execute a step function algorithm to adjust the at least one energy signal characteristic, wherein the processor executes the step function algorithm to:
compare the calculated first impedance to a plurality of impedance thresholds less than the predetermined impedance level, wherein each of the plurality of impedance thresholds is correlated to a tissue sealing state;
determine that the calculated first impedance has crossed an impedance threshold of the plurality of impedance thresholds; and
modify the at least one energy signal characteristic of the first electrosurgical energy signal by a step to establish the second electrosurgical energy signal for delivery to the first electrode and the second electrode.
13. The robotic surgical system of claim 12 , wherein the control circuit comprises:
a current sense circuit configured to measure the first current and the second current; and
a voltage sense circuit configured to measure the first voltage and the second voltage.
14. The robotic surgical system of claim 12 , wherein the first control signal is configured to deliver the first electrosurgical energy signal to the first electrode and the second electrode for a first variable period of time, the first variable period of time being between a time the first electrosurgical energy signal is delivered to the first electrode and the second electrode and a time the calculated first impedance crosses the impedance threshold.
15. The robotic surgical system of claim 12 , wherein the at least one energy signal characteristic comprises a current, a voltage, or a frequency.
16. A surgical tool, comprising:
a tool mounting portion, comprising:
a control circuit configured to:
generate a first energy control signal to deliver a first electrosurgical energy signal for energizing a first electrode of a first end effector jaw and a second electrode of a second end effector jaw to treat tissue in contact with the first electrode and the second electrode;
measure a current supplied to the first electrode and the second electrode;
measure a voltage applied to the first electrode and the second electrode;
calculate impedance based on the measured current and the measured voltage;
compare the calculated impedance to a predetermined impedance level;
generate a second energy control signal to deliver a second electrosurgical energy signal to the first electrode and the second electrode when the calculated impedance is less than the predetermined impedance level, wherein generating the second energy control signal to deliver the second electrosurgical energy signal comprises adjusting at least one energy signal characteristic between the first electrosurgical energy signal and the second electrosurgical energy signal based on the calculated impedance; and
generate a drive control signal to advance a blade that is longitudinally translatable within channels defined in the first end effector jaw and the second end effector jaw when the calculated impedance is greater than or equal to the predetermined impedance level;
wherein the control circuit is configured to adjust the at least one energy signal characteristic by:
comparing the calculated impedance to a plurality of impedance thresholds less than the predetermined impedance level, wherein each of the plurality of impedance thresholds is correlated to a tissue sealing state;
determining that the calculated impedance has crossed an impedance threshold of the plurality of impedance thresholds; and
modifying the at least one energy signal characteristic of the first electrosurgical energy signal by a step to establish the second electrosurgical energy signal for delivery to the first electrode and the second electrode, wherein the at least one energy signal characteristic comprises a current, a voltage, or a frequency.
17. A robotic surgical system, comprising:
a control circuit configured to:
generate a first energy control signal to deliver a first electrosurgical energy signal for energizing a first electrode of a first end effector jaw and a second electrode of a second end effector jaw;
measure a current supplied to the first and second electrodes;
measure a voltage applied to the first and second electrodes;
calculate impedance based on the measured current and the measured voltage;
compare the calculated impedance to a predetermined tissue impedance level; generate a second energy control signal to deliver a second electrosurgical energy signal to the first and second electrodes when the calculated impedance is less than the predetermined tissue impedance level, wherein the first electrosurgical energy signal and the second electrosurgical energy signal are defined by at least one energy signal characteristic, and wherein generating the second energy control signal to deliver the second electrosurgical energy signal comprises adjusting the at least one energy signal characteristic between the first electrosurgical energy signal and the second electrosurgical energy signal based on the calculated impedance; and
generate a drive control signal to activate an ultrasonic blade coupled to an ultrasonic transducer when the calculated impedance is greater than or equal to the predetermined tissue impedance level
wherein the control circuit is configured to adjust the at least one energy signal characteristic by:
comparing the calculated impedance to a plurality of impedance thresholds less than the predetermined tissue impedance level, wherein each of the plurality of impedance thresholds is correlated to a tissue sealing state;
determining that the calculated impedance has crossed an impedance threshold of the plurality of impedance thresholds; and
modifying the at least one energy signal characteristic of the first electrosurgical energy signal by a step to establish the second electrosurgical energy signal for delivery to the first electrode and the second electrode, wherein the at least one energy signal characteristic comprises a current, a voltage, or a frequency.