Handling Trolley Localization Using IMU Stop Detection
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Solution Overview
Problem
Existing methods for accurately locating handling trolleys in premises are either expensive or lack sufficient accuracy, particularly due to obstacles interfering with satellite signals and the limitations of low-cost inertial MEMS units.
Innovation Solution
A system comprising communications beacons and an onboard electronic module with inertial motion detectors, which includes a device for detecting angular motion to correct linear motion data and reset speeds when the trolley stops, ensuring reliable position measurement and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If satellite positioning signals (GPS) are used to locate trolleys, then positioning coverage can be achieved, but the cost is high and obstacles in the premises may block the signals
Solution Approach 1:
The patent introduces an intermediary inertial measurement unit (IMU) that indirectly measures position through acceleration and angular rate data, bypassing the need for direct satellite signal reception. This mediator allows positioning to function independently of external signal blockage by obstacles.
Solution Approach 2:
The patent replaces the electromagnetic satellite positioning system with a mechanical inertial measurement system that uses accelerometers and gyroscopes to track motion, substituting a system vulnerable to signal blockage with one that is self-contained and obstacle-independent.
2Ease of manufacture
If low-cost inertial MEMS units are used to locate trolleys, then cost is reduced, but positioning accuracy deteriorates due to accumulated errors
Solution Approach 1:
The patent implements feedback by using the angular rate data from the gyroscope to detect when the trolley has stopped moving, then resetting the velocity integration from the accelerometer. This feedback mechanism prevents error accumulation by periodically recalibrating the position calculation when motion ceases.
Solution Approach 2:
The system performs periodic error correction by continuously monitoring angular motion and resetting the linear motion integration whenever the trolley stops. This periodic resetting action prevents the accumulation of drift errors that would otherwise degrade positioning accuracy over time.
3Reliability
If telecommunications beacons and signal travel time measurement are used to locate trolleys, then positioning can be achieved regardless of obstacles, but sufficient accuracy is difficult to obtain
Solution Approach 1:
The patent replaces the telecommunications signal-based positioning system with a mechanical inertial measurement system that directly measures acceleration and angular motion, achieving superior accuracy by using physical motion detection rather than signal propagation time measurement.
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
Enables accurate and cost-effective localization of trolleys by integrating angular motion detection to correct linear motion errors, enhancing positioning reliability and accuracy even in environments with obstacles.
Implementation Method 1
an inertial motion detector unit that comprises a device for detecting linear motion along axes of a detection reference frame and a device for detecting angular motion about the axes of the detection reference frame
Implementation Method 2
a device for detecting angular motion, which device comprises gyros arranged on the axes of the detection reference frame in order to measure the movements of the detection reference frame
Data Source
AI summary
System for finding at least one mobile trolley in a locale, the system including at least one communication beacon which has a range covering the locale and which is connected to a computer control unit, and at least one electronic module mounted on the trolley and including a transmission device arranged to transmit position data to the communication beacon, and an inertial motion detection hub that includes a device for detecting linear motion along axes of a detection reference system and a device for detecting angular motion about the axes of the detection reference system and that is arranged to provide position data on the basis of linear motion measurement data and angular motion measurement data, the module being mounted on an element of the trolley such that any movement of the trolley within the locale causes angular movement of the element, the system being arranged to detect when the trolley is stopped when the angular motion measurement data correspond to zero angular motion at one measurement instant and being arranged to set to zero speeds calculated on the basis of the linear motion measurement data corresponding to the same measurement instant.