METHOD FOR CONTROLLING SMART ENERGY DEVICES
A method for controlling an operation of an ultrasonic blade of an ultrasonic electromechanical system is disclosed. The method includes providing an ultrasonic electromechanical system comprising an ultrasonic transducer coupled to an ultrasonic blade via an ultrasonic waveguide; applying, by an energy source, a power level to the ultrasonic transducer; determining, by a control circuit coupled to a memory, a mechanical property of the ultrasonic electromechanical system; comparing, by the control circuit, the mechanical property with a reference mechanical property stored in the memory; and adjusting, by the control circuit, the power level applied to the ultrasonic transducer based on the comparison of the mechanical property with the reference mechanical property.
1 . A method for controlling an operation of an ultrasonic blade of an ultrasonic electromechanical system, the method comprising:
providing an ultrasonic electromechanical system comprising an ultrasonic transducer coupled to an ultrasonic blade via an ultrasonic waveguide;
applying, by an energy source, a power level to the ultrasonic transducer;
determining, by a control circuit coupled to a memory, a mechanical property of the ultrasonic electromechanical system;
comparing, by the control circuit, the mechanical property with a reference mechanical property stored in the memory; and
adjusting, by the control circuit, the power level applied to the ultrasonic transducer based on the comparison of the mechanical property with the reference mechanical property.
2 . The method of claim 1 , wherein determining, by a control circuit, a mechanical property of the ultrasonic electromechanical system comprises determining, by the control circuit, a resonant frequency of the ultrasonic blade.
3 . The method of claim 1 , further comprising determining, by the control circuit, a temperature of the ultrasonic blade.
4 . The method of claim 3 , wherein determining, by the control circuit, a temperature of the ultrasonic blade comprises determining, by the control circuit, the temperature of the ultrasonic blade based on a resonant frequency of the ultrasonic blade.
5 . The method of claim 3 , wherein determining, by the control circuit, a temperature of the ultrasonic blade comprises measuring, by the control circuit, a phase angle φ between a voltage signal Vg(t) and a current signal Ig(t) applied to the ultrasonic transducer by the energy source.
6 . The method of claim 3 , wherein determining, by the control circuit, a temperature of the ultrasonic blade comprises measuring, by the control circuit, an impedance Zg(t) equal to a ratio of a voltage signal Vg(t) to a current signal Ig(t) applied to the ultrasonic transducer by the energy source.
7 . A method for determining a characteristic of an ultrasonic blade of an ultrasonic electromechanical system, the method comprising:
providing an ultrasonic electromechanical system comprising an ultrasonic transducer coupled to an ultrasonic blade via an ultrasonic waveguide;
applying, by an energy source, a power level to the ultrasonic transducer; and
determining, by a control circuit coupled to a memory, the characteristic of the ultrasonic blade.
8 . The method of claim 7 , wherein determining, by a control circuit coupled to a memory, the characteristic of the ultrasonic blade comprises determining, by the control circuit coupled to the memory, a temperature of the ultrasonic blade.
9 . The method of claim 8 , wherein determining, by the control circuit coupled to the memory, a temperature of the ultrasonic blade comprises:
determining, by the control circuit, a resonant frequency of the ultrasonic blade; and
comparing, by the control circuit, the resonant frequency of the ultrasonic blade to a reference resonant frequency stored in the memory of the control circuit.
10 . The method of claim 8 , wherein determining, by the control circuit coupled to the memory, a temperature of the ultrasonic blade comprises measuring, by the control circuit, a phase angle φ between a voltage signal Vg(t) and a current signal Ig(t) applied to the ultrasonic transducer by the energy source.
11 . The method of claim 8 , wherein determining, by the control circuit coupled to the memory, a temperature of the ultrasonic blade comprises measuring, by the control circuit, an impedance Zg(t) equal to a ratio of a voltage signal Vg(t) to a current signal Ig(t) applied to the ultrasonic transducer by the energy source.
12 . The method of claim 8 , further comprising generating, by the control circuit, a temperature estimator and state space model of the temperature of the ultrasonic blade as a function of a resonant frequency of the ultrasonic electromechanical system based on a set of non-linear state space equations.
13 . The method of claim 12 , wherein generating, by the control circuit, a state space model of the temperature of the ultrasonic blade based on a set of non-linear state space equations comprises generating, by the control circuit, a state space model defined by:
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14 . The method of claim 12 , further comprising applying, by the control circuit, a Kalman filter to improve the temperature estimator and state space model.
15 . The method of claim 14 , wherein applying, by the control circuit, a Kalman filter to improve the temperature estimator and state space model comprises applying, by the control circuit, a Kalman filter having a state variance of a state estimator of the Kalman filter defined by:
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16 . A method of determining a functional status of an ultrasonic electromechanical system, the method comprising:
providing an ultrasonic electromechanical system comprising an ultrasonic transducer coupled to an ultrasonic blade via an ultrasonic waveguide;
applying, by an energy source, a power level to the ultrasonic transducer; and
determining, by a control circuit coupled to a memory, the functional status of the ultrasonic blade.
17 . The method of claim 16 , wherein determining, by a control circuit coupled to a memory, the functional status of the ultrasonic blade comprises determining, by the control circuit coupled to the memory, an instability of the ultrasonic blade.
18 . The method of claim 17 , further comprising:
determining, by the control circuit, a temperature of the ultrasonic blade; and
comparing, by the control circuit, the temperature of the ultrasonic blade to an ultrasonic blade instability trigger point threshold.
19 . The method of claim 16 , wherein determining, by a control circuit coupled to a memory, the functional status of the ultrasonic blade comprises determining, by the control circuit coupled to the memory, an initial temperature of the ultrasonic blade.
20 . The method of claim 19 , further comprising:
measuring, by the control circuit, a resonant frequency of the ultrasonic blade prior to applying, by the energy source, the power level to the ultrasonic transducer;
comparing, by the control circuit, the measured resonant frequency to a baseline resonant frequency; and
determining, by the control circuit, the initial temperature of the ultrasonic blade based on the comparison of the measured resonant frequency with the baseline resonant frequency.