System and Method Enabling Sensorless Actuator
OwnerDavid Zeltzerinventor
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Abstract
An actuator having a two-parameter energy converter is coupled to a transducer and is driven by a controller. Prior to assembly and operation of the actuator, a calibration procedure is performed. The calibration procedure, together with the unique controller, enables accurate control of the output parameters of the actuator. In one example, the parameters are rate and force, and the calibration and controller enable accurate control of the rate and force at the output of the actuator by measuring only the rate at the output of the energy converter. Consequently, no sensors are needed at the output of the actuator, i.e., at the output of the transducer, where the load is applied.
Claims16
A method of operating an actuator operating on a load, the actuator comprising a machine and a transmission, the machine comprising an energy converter and the transmission comprising a transducer having a transducing ratio, the method comprising:
- measuring machine velocity of the machine shaft;
- using the measured machine velocity to obtain machine moment from pre-established velocity-moment curves;
- calculating the transmission velocity using the machine velocity and transmission ratio;
- calculating the transmission moment using the calculated transmission velocity;
- predicting actual transmission velocity using the internal losses model;
- predicting actual transmission moment using the predicted actual transmission velocity, the internal losses model and external losses model.
An actuator comprising:
- an energy converter characterized by a first parameter and a second parameter, the first and second parameters being interrelated;
- a sensor coupled to the output of the energy converter and measuring magnitude of the first parameter;
- a transducer being characterized by a transducing ratio;
- a controller comprising:
- a converter calibration module storing curves interrelating the first and second parameters;
- an internal losses model;
- an external losses model;
- a feedback loop receiving the magnitude of the first parameter from the sensor and utilizing the magnitude of the first parameter, transducing ratio, internal losses model and external losses model to calculate control signal to drive the energy converter.
A method for controlling an actuator operating on an arbitrary load, the actuator comprising an energy converter and a transducer, the method comprising:
- performing converter calibration of the energy converter operating independently of the transducer,
- wherein performing the converted calibration further comprises:
- coupling rate and force sensors to the output or the energy converter;
- operating the converter by providing a plurality of activation signals of different values;
- and,
- constructing rate-force curves characteristic of the energy converter using outputs provided by the rate and force sensors coupled to the energy converter, wherein values of at least one of the rate and the force are scaled to correspond to a known set of values of the other within an operational regime;
- performing actuator calibration of the actuator operating without a load;
- performing static load calibration of the actuator operating with applied static load;
- and,
- using the converter calibration, actuator calibration, and static load calibration to form a feedback loop to control operation of the actuator on the arbitrary load.
Dependencies are inferred from the claim text.