Activation of energy devices

A surgical instrument comprising:

• an ultrasonic blade;
• an arm movable relative to the ultrasonic blade between an open position and a closed position;
• a transducer assembly coupled to the ultrasonic blade, the transducer assembly comprising at least two piezoelectric elements configured to ultrasonically oscillate the ultrasonic blade;
• a first sensor configured to measure a first force as the arm transitions to the closed position;
• a second sensor configured to measure a second force as the arm transitions to the open position;
• and
• a control circuit coupled to the transducer assembly, the first sensor, and the second sensor, the control circuit configured to:
• activate the transducer assembly based on the first force exceeding a first threshold while the second force is below a second threshold;
• activate the transducer assembly based on the second force exceeding the second threshold while the first force is below the first threshold;
• and
• deactivate the transducer assembly based on the first force being below the first threshold and the second force being below the second threshold.

A surgical instrument comprising:

• an ultrasonic blade;
• an arm pivotable relative to the ultrasonic blade between an open position and a closed position;
• a transducer assembly coupled to the ultrasonic blade, the transducer assembly comprising at least two piezoelectric elements configured to ultrasonically oscillate the ultrasonic blade;
• a first sensor configured to sense a first force as the arm transitions to the closed position;
• a second sensor configured to sense a second force as the arm transitions to the open position;
• and
• a control circuit coupled to the transducer assembly, the first sensor, and the second sensor, the control circuit configured to:
• determine a state of the arm based on the first force sensed by the first sensor relative to a first threshold and the second force sensed by the second sensor relative to a second threshold, wherein the state comprises an open state, an in-between state, and a closed state;
• and
• activate the transducer assembly based on the state of the arm.