Actuator Characterization via Capacitance Measurement
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Solution Overview
Problem
Existing actuator control systems require complex calibration and pre-programmed values for determining maximum displacement and offset voltages, which are not feasible without prior knowledge of the actuator type, temperature, and orientation, leading to prohibitive measurement system complexity.
Innovation Solution
An integrated circuit chip with a capacitance sensor, control logic, and actuator driver that incrementally adjusts driving signals to measure actuator capacitance, allowing for characterization of actuator attributes without pre-programmed values, microprocessors, or external temperature sensors, by storing signal values associated with capacitance changes and using threshold comparisons to determine curve end points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pre-programmed values and complex calibration systems are used to determine actuator characteristics, then measurement precision is improved, but device complexity increases prohibitively
Solution Approach 1:
The actuator controller performs self-calibration by automatically determining its own transfer function characteristics through capacitance measurements during actuator movement, eliminating the need for external calibration equipment and pre-programmed values. The system serves itself by using its own actuator as the measurement object and storing the derived characteristics in its memory.
Solution Approach 2:
The patent replaces complex mechanical calibration systems and external measurement equipment with an electrical capacitance measurement system integrated into the actuator controller. The capacitance sensor and control logic electronically determine actuator characteristics without requiring physical calibration tools or microprocessors.
2Measurement precision
If temperature sensors and orientation detection are implemented to account for environmental variations, then actuator response accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The system automatically adapts to temperature and orientation changes by continuously monitoring capacitance variations during actuator movement and dynamically adjusting the transfer function parameters. The actuator controller performs self-calibration under actual operating conditions without requiring separate temperature sensors or orientation detectors.
Solution Approach 2:
The patent changes the measurement parameter from direct position sensing to capacitance measurement, which inherently captures the effects of temperature and orientation variations. By measuring capacitance at different actuator positions and deriving the transfer function from these measurements, the system automatically compensates for environmental factors without additional sensors.
3Speed
If lookup tables and pre-programmed voltage values are used for actuator control, then control speed is improved, but adaptability to different actuator types and environmental conditions deteriorates
Solution Approach 1:
The patent transitions from static pre-programmed lookup tables to a dynamic transfer function that is automatically determined through capacitance measurements. The control system adapts in real-time to the specific actuator characteristics and environmental conditions by continuously measuring capacitance and updating the transfer function parameters, maintaining both speed and adaptability.
Solution Approach 2:
The actuator controller with automatic transfer function determination can work with different types of actuators without requiring re-programming or type-specific calibration data. The system universally determines the transfer function through capacitance measurements applicable to any capacitive actuator, making the control system multi-functional and highly adaptable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise characterization of actuators, eliminating the need for look-up tables and complex calibration, and adapts to changes in orientation and temperature, simplifying the measurement system while maintaining accurate actuator control.
Implementation Method 1
The capacitance sensor may include circuitry for determining a signal representative of the capacitance of the actuator
Data Source
AI summary
An apparatus and method for determining characterizing attributes of an actuator is provided. An actuator may be moved to a maximum capacitance position. At the maximum capacitance position, an initial measurement of the actuator capacitance is made. The actuator is moved a predetermined increment toward a first extreme position, and the actuator capacitance is again measured. If the capacitance changed by a threshold amount, the signal preceding the signal that caused the actuator to move is recorded as an approximate response curve end point, or the first extreme position. The actuator is again moved a predetermined increment toward a second extreme position. After each move, the capacitance is measured. If it is determined the capacitance did change by a threshold amount from the previously measured capacitance, the signal related to the previously measured capacitance is recorded as an approximate response curve end point, or the second extreme position.