US 9,731,744 B2Granted

Estimating motion of wheeled carts

AssigneeGatekeeper Systems, Inc.

InventorsScott J. Carter, Stephen E. Hannah, Jesse M. James, Narayanan V. Ramanathan

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Abstract

Examples of systems and methods for locating movable objects such as carts (e.g., shopping carts) are disclosed. Such systems and methods can use dead reckoning techniques to estimate the current position of the movable object. Various techniques for improving accuracy of position estimates are disclosed, including compensation for various error sources involving the use of magnetometer and accelerometer, and using vibration analysis to derive wheel rotation rates. Also disclosed are various techniques to utilize characteristics of the operating environment in conjunction with or in lieu of dead reckoning techniques, including characteristic of environment such as ground texture, availability of signals from radio frequency (RF) transmitters including precision fix sources. Such systems and methods can be applied in both indoor and outdoor settings and in retail or warehouse settings.

Claims23

Dependent claims

A navigation system for a human-propelled cart, the navigation system comprising:

a magnetometer configured to determine a heading of the human-propelled cart;
a vibration sensor configured to measure vibration data of the human-propelled cart;
a communication system configured to communicate with a wheel of the human-propelled cart, the wheel comprising a brake configured to inhibit rotation of the wheel in response to receipt of a locking signal;
and
a hardware processor programmed to:
estimate a speed of the human-propelled cart based at least in part on the vibration data from the vibration sensor, the hardware processor programmed to:
analyze a spectrum of the vibration data;
identify a first peak in the spectrum of the vibration data, the first peak associated with vibration data for vibrations associated with forward or rearward movement of the human-propelled cart;
determine a rotation rate of the wheel to be a harmonic frequency of the frequency of the first peak in the spectrum of the vibration data;
and
estimate the speed based on the rotation rate and a circumference of the wheel;
and
estimate a position of the human-propelled cart based at least in part on the estimate speed and the heading of the human-propelled cart.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/256,300Filed 2 Sep 2016 · us provisional application
Priority: 4 Sep 2015
Published: US 2017/0066464 A19 Mar 2017
Granted: 15 Aug 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification39 codes

G08G 1/207
Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles: with respect to…
B60T 7/12
Brake-action initiating means: for automatic initiation; for initiation not subject to will of driver or passenger
B60T 7/18
Operated by remote control, i.e. initiating means not mounted on vehicle: operated by wayside apparatus
B62B 3/14
Hand carts having more than one axis carrying transport wheels; Steering devices therefor; Equipment therefor: characterised by provisions for…