Active Inceptor Hands-Off Detection for Force Offset Compensation
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Solution Overview
Problem
Active inceptor systems experience drift in force sensor output due to environmental changes, leading to offset issues that can be misinterpreted as user input, limiting system performance and affecting the feel of the user input device.
Innovation Solution
A method to detect the hands-off status of a user input device, applying filters to remove force offsets only when the user is not interacting with the device, using a combination of lag filters and threshold comparisons to differentiate between user and environmental effects, and compensating force offsets through integrator and rate limiter circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force offset compensation is continuously applied, then measurement precision is improved, but the user experience deteriorates due to perceptible vibrations and movements
Solution Approach 1:
The patent implements dynamic adjustment of the compensation filter by switching between active compensation mode and inactive mode based on detected user interaction. The system dynamically changes its behavior from continuously removing offsets to selectively applying compensation only when appropriate, resolving the contradiction between measurement precision and user experience.
Solution Approach 2:
The system uses feedback from force sensor data and interaction detection to control the compensation filter. By monitoring whether the user is interacting with the input device, the system intelligently decides when to apply offset compensation, ensuring both accuracy and comfort.
2Reliability
If offset removal is applied during user interaction, then system performance is improved, but the user feels unintended vibrations and movements
Solution Approach 1:
The patent applies preliminary detection of user interaction before applying offset removal. By detecting whether the user is interacting with the device in advance, the system prevents the harmful effect of vibrations from occurring in the first place, rather than correcting them after they occur.
Solution Approach 2:
The compensation filter dynamically adjusts its operation based on real-time detection of user interaction state, being active only when the user is not interacting with the device. This dynamic control prevents harmful vibrations while maintaining system performance.
3Measurement precision
If environmental offsets are removed, then measurement accuracy is improved, but user input may be misinterpreted leading to incorrect compensation
Solution Approach 1:
The system uses feedback from multiple sources including force sensor data, interaction detection, and filter output analysis to determine when to apply compensation. This multi-source feedback mechanism ensures that offset removal is applied only when environmental drift is present and not when it represents legitimate user input.
Solution Approach 2:
The patent applies preliminary filtering and threshold comparison to detect hands-off status before applying offset compensation. This preliminary action ensures that the system correctly identifies environmental offsets versus user input, preventing misinterpretation of user actions.
Data Source
AI summary
A method to detect a hands off status of a user input device is disclosed. The method comprising filtering a sensed force, acting on the user input device, using a first lag filter to provide a first output, the lag filter comprising a first lag time constant. Filtering the sensed force using a second lag filter, substantially in parallel with the first filter, to provide a second output, the second lag filter comprising a second lag time constant greater than the first lag time constant. Comparing with a first threshold value, in a first comparison, a magnitude of a difference between the first output and the second output. Comparing with a second threshold value, in a second comparison, a magnitude of the second output. Designating the user device to have a hands off status based on the first comparison and the second comparison.