Active Inceptor Force Offset Compensation for Sensor Drift
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Solution Overview
Problem
Active inceptor systems face challenges with sensors that slowly drift over time, causing environmental offsets that affect the performance of active inceptor systems, such as offsets in sensed or actual position, and erosion of deadband force, which are not effectively distinguished from user inputs.
Innovation Solution
A method to detect a hands-off status of the user input device, applying filters to remove environmental offsets imperceptibly, using lag filters and integrators to compensate for force drift, and a redundant channel for redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are used to detect user input force, then measurement precision is improved, but sensor drift over time causes environmental offsets that worsen measurement accuracy
Solution Approach 1:
The system performs preliminary action by detecting hands-off status and applying offset compensation filters before the drift affects measurement accuracy. The filter is proactively engaged when the user releases the control, compensating for environmental offsets before they accumulate and degrade long-term reliability.
Solution Approach 2:
The system applies preliminary anti-action by using the lag filter and integrator to counteract environmental offsets before they significantly impact measurements. The compensation mechanism acts in advance during hands-off periods to prevent drift from compromising measurement precision during subsequent user interactions.
2Measurement precision
If offset compensation is applied continuously, then measurement accuracy is improved, but user perception of artificial forces worsens
Solution Approach 1:
The system implements periodic action by applying offset compensation only during hands-off periods rather than continuously. The lag filter and integrator are activated periodically when the user releases the control, allowing accuracy improvement without continuously applying forces that the user could perceive as artificial during active manipulation.
Solution Approach 2:
The system uses dynamics by making the compensation mechanism conditional and adaptive. The hands-off status detection dynamically controls when the filter is applied, transitioning between compensation and normal operation modes based on user interaction state, thereby avoiding perceptible artificial forces while maintaining accuracy.
3Object-affected harmful factors
If filter time constants are increased to remove offsets imperceptibly, then user perception of artificial forces is reduced, but responsiveness to user inputs worsens
Solution Approach 1:
The system applies preliminary anti-action by removing offsets during hands-off periods before they can affect responsiveness. The lag filter with larger time constant operates in advance during idle periods, eliminating drift without interfering with the speed of response when the user actually manipulates the control.
Solution Approach 2:
The system uses periodic action by alternating between compensation mode (during hands-off periods with larger time constant filter) and responsive mode (during user interaction with smaller time constant filter). This periodic switching allows imperceptible offset removal without sacrificing responsiveness during active use.
Data Source
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AI summary
A method is disclosed for calculating a force offset compensation, the method comprising: operating an integrator, wherein the input to the integrator is zero if an indication is received that the user is hands on the user input device; subtracting a last output from the integrator from a sensed force acting on the user input device to obtain a first subtraction output; using the first subtraction output as the input to the integrator; equating, after a predetermined number of cycles of the integrator, the output of the integrator to be equal to the force offset compensation.