Closed-Loop Sensor Nulling for Position and Movement Detection
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Solution Overview
Problem
Existing sensor systems face challenges in accurately detecting the movement and position of targets, particularly in specific measuring directions, due to temperature dependency and small signal values, which overwhelm A/D converters, and struggle to separate distance information from movement information.
Innovation Solution
A sensor arrangement with a transmitting/receiving coil system that regulates signals to zero using a closed control loop, allowing for the extraction of target position and movement information by plotting control signal deviations in a four-quadrant representation, enabling separate detection of distance and movement along measuring directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inductive or capacitive sensing methods are used to detect physical parameters, then the sensor can operate in various environments, but the small signal values produced overwhelm A/D converters and reduce measurement precision
Solution Approach 1:
The patent introduces a feedback signal as an intermediary element that mediates between the small sensor output signal and the A/D converter. This feedback signal, generated by a controllable signal source and adjusted through feedback control, serves as a reference that enables precise measurement of small signal variations without directly overwhelming the converter, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent implements a feedback mechanism where the output of the sensor is fed back through a controllable signal source to generate a compensating signal. This feedback loop allows the system to automatically adjust and maintain optimal operating conditions, enabling precise detection of small physical parameter changes while managing the complexity of signal processing through automated control
2Reliability
If temperature compensation is implemented in inductive measuring systems, then measurement accuracy improves, but the system complexity and calibration requirements increase
Solution Approach 1:
The patent employs a self-service approach where the system uses its own output signal and feedback mechanism to automatically compensate for temperature effects. The controllable signal source adjusts the feedback signal based on the actual sensor output, creating a self-regulating system that maintains temperature stability without requiring external compensation circuits or complex calibration procedures
Solution Approach 2:
The patent utilizes parameter changes in the feedback signal to compensate for temperature effects. By dynamically adjusting the amplitude and phase of the feedback signal through the controllable signal source, the system adapts to temperature variations and maintains measurement accuracy, resolving the contradiction between reliability and device complexity
3Measurement precision
If the received signal is regulated to zero using feedback control, then the control value contains pure position information, but the system requires precise calibration and is sensitive to external influences
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the feedback control system to establish a baseline zero point before actual measurements begin. The controllable signal source is pre-adjusted to generate the appropriate feedback signal that nullifies the sensor output under known reference conditions, thereby preparing the system to accurately detect deviations from this calibrated state while reducing sensitivity to external influences
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
This approach allows for precise detection of target position and movement, independent of distance and external influences, with enhanced sensitivity and ability to handle small signal changes, effectively addressing the limitations of existing systems.
Implementation Method 1
method for inductive or capacitive detection of at least one target 1.2 by determining at least one physical parameter
Implementation Method 2
A control driver (1.5) regulates the non-zero signal via a closed control loop with a control signal (1.6) acting on the reception path (1.7), even when the target (1.2) is present in the detection area (10), in order to achieve a controlled state
Data Source
Figure 1
Figure 2
Figure 3~4b
AI summary
A sensor arrangement for determining at least one physical parameter of a sensor unit which is activated by at least one periodic excitation, comprising a detection region in which changes of the parameter in the surroundings of the sensor unit lead to an output signal from the sensor unit. The sensor unit is wired such that if there is no change of the parameter in the detection region the output signal is a zero signal at the output of the sensor unit, whereas if there are changes of the parameter in the detection region the output signal is a signal that is not zero and which has a specific amplitude and phase. By means of a closed-loop control, the non-zero signal in the receive path is adjusted to achieve an adjusted state at zero even in the presence of changes of the parameter in the detection region. Inherent in the control signal used for this adjustment is a deviation (Δx, Δy) of the control signal from the adjusted state, which deviation represents information about the parameter. To create a sensor arrangement and a method in which values of a physical parameter in a detection region can be clearly determined, in a four-quadrant representation of the deviation (Δx, Δy) in the form of a vector analysis in a phase space of the control signal, the angle of an imaginary vector (2.6) relative to the x axis of an x, y coordinate system, said vector leading from the origin (2.7) of the x, y coordinate system to a measuring point (2.5) and said origin corresponding to the adjusted state, represents a measurement for the change of the parameter along a direction, and/or the magnitude of the imaginary vector (2.6) represents a measurement for the change of the parameter along a further direction.