Seat Massage Bladder Control via Single Pressure Sensor
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Solution Overview
Problem
The high cost of pressure sensors for multiple bladders in seat assemblies, as each bladder typically requires its own sensor, leads to increased overall costs without significant reduction in functionality.
Innovation Solution
Implementing a single pressure sensor for one bladder and using a controller to determine the inflation time for other bladders based on the fill time of the sensor-equipped bladder, adjusting for factors like bladder size and air tubing length, to replicate the inflation process across all bladders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each bladder is equipped with its own pressure sensor, then the accuracy of pressure detection for each bladder is improved, but the overall cost of the seat assembly increases significantly
Solution Approach 1:
A single pressure sensor is used to control multiple bladders through a unified control strategy. The controller manages inflation for all bladders by referencing the fill time from one sensor-equipped bladder, making the sensor system universal rather than dedicated to each individual bladder.
Solution Approach 2:
The inflation process of the first bladder (with sensor) is copied to control the inflation of subsequent bladders. The controller records the fill time of the first bladder and applies this timing pattern to inflate other bladders without requiring individual sensors, thus replicating the control approach across multiple bladders.
2Device complexity
If a single pressure sensor is used for multiple bladders, then the cost of the seat assembly is reduced, but the ability to independently monitor pressure in each bladder is worsened
Solution Approach 1:
The system performs preliminary measurement by inflating the first bladder with the pressure sensor to establish a reference fill time. This preliminary action allows the controller to predict and control the inflation timing of subsequent bladders without needing to measure each one individually, maintaining control precision while reducing sensor count.
Solution Approach 2:
The controller uses feedback from the pressure sensor on the first bladder to adjust and control the inflation timing of subsequent bladders. The fill time information feeds back into the control algorithm, enabling the system to maintain consistent inflation patterns across all bladders using a single sensor's data.
3Device complexity
If the inflation time of the first bladder is used to control other bladders, then the number of pressure sensors is reduced, but the accuracy of inflation timing for bladders without sensors is worsened
Solution Approach 1:
The controller adjusts inflation parameters (timing, duration) for subsequent bladders based on the reference fill time from the first bladder. By modifying these parameters according to the established timing pattern and bladder characteristics, the system maintains inflation accuracy without requiring individual sensors for each bladder.
Solution Approach 2:
The system uses a partial measurement approach where only one bladder is fully monitored with a sensor, but this partial information is sufficient to control the entire system. The single sensor provides enough data to infer and control the inflation timing of all other bladders, avoiding the need for complete individual monitoring of each bladder.
Data Source
AI summary
A seat assembly includes first and second bladders and a controller. The first bladder has a sensor configured to detect a pressure of the first bladder. The controller is configured to inflate the first bladder to a target pressure, as detected by the sensor, and to inflate the second bladder based on time expended for the first bladder to be inflated to the target pressure.