Sliding Step Plate Expansion Element for Reliable Force Sensing
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Solution Overview
Problem
Existing sliding steps for public transport vehicles face challenges in reliable force sensing due to mechanical vibrations, dirt, moisture, and wear, particularly with strain gauge sensors, which are complex to install and maintain, and not easily adaptable to different vehicle types or retrofitting.
Innovation Solution
The solution involves arranging strain measuring elements at an angle on cranked sections between rollers, with multiple gauges measuring deformations independently to determine forces in various directions, and using protected strain gauges with a cover for reduced wear and soiling, allowing for simple assembly and retrofitting with minimal changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauge sensors are attached to the inside of the side panels, then force measurement is enabled, but the measurement reliability deteriorates due to zero point shifting and installation sequence influence
Solution Approach 1:
A cranked section is introduced as an intermediary component between the side panel and the strain gauge sensor. This cranked section serves as a mediator that transforms the complex stress state at the screw connection into a uniaxial bending moment that can be reliably measured by the strain gauge, eliminating the zero point shifting problem caused by direct attachment to the side panel.
Solution Approach 2:
The measurement function is extracted from the side panel structure itself and transferred to a separate cranked section. This allows the strain gauge to measure only the specific bending moment generated by vertical forces on the step plate, isolating the measurement from other interfering stresses and installation variations.
2Reliability
If complete DMS systems with housings are used, then sensor protection is improved, but device complexity and manufacturing costs increase
Solution Approach 1:
The cranked section is integrated directly into the side panel structure, merging the support function with the measurement function. This eliminates the need for separate housings and mounting brackets, reducing device complexity while maintaining sensor protection through the structural design itself.
Solution Approach 2:
The cranked section serves multiple functions simultaneously: it provides structural support for the roller, enables force measurement through its bending deformation, and protects the strain gauge sensor through its integrated design. This multi-functionality reduces the need for additional protective components.
3Measurement precision
If strain gauges are arranged between the sliding step plate and link components, then force sensing is enabled, but installation complexity and adaptability to different vehicle types deteriorates
Solution Approach 1:
The measurement system is segmented into a modular cranked section that can be independently attached to the side panel. This modular design allows the same measurement principle to be applied across different vehicle types without requiring complex integration with vehicle-specific link components, improving adaptability.
4Measurement precision
If measuring elements are arranged in the frame fastening area, then vertical force detection is enabled, but installation complexity and retrofitting difficulty increase
Solution Approach 1:
The cranked section is pre-formed with the specific geometry needed to generate reliable bending moments under vertical load. This preliminary preparation of the measurement element simplifies the final installation process, as the complex stress analysis and geometry optimization have already been completed in the design and manufacturing phase.
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 configuration enables reliable force measurement, reduces manufacturing costs, and simplifies installation and maintenance, while being adaptable to different vehicle types and suitable for retrofitting, providing accurate force detection with minimal influence from installation position or wear.
Implementation Method 1
at least one of the side cheeks of the sliding step in the region of one of the rollers has a cranked section which is arranged between two rollers and which has a strain measuring element for detecting deformations
Data Source
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AI summary
The invention relates to a sliding step (20) for a public passenger transport vehicle, comprising a step plate (24), which can be horizontally drawn in and out in a slide-in/slide-out direction by a drive, having two sides and a steps surface arranged between the sides, wherein the step plate (24) has at least two rollers arranged on the sides, which roll in a rail secured to the vehicle. At least one of the sides has a bent section in the region of one of the rollers, which bent section is arranged between the two rollers, and has an expansion measurement element for detecting deformations.