Abstract: A system for monitoring shopping carts or other human-propelled carts includes wireless access points that communicate bi-directionally on a wireless network with wheel assemblies of the carts. The system supports both unicast and multicast command transmissions from the access points to the wheel assemblies, including multicast transmissions in which the target wheel assemblies are specified in terms of their states. For example, an access point can transmit a command that is addressed to all wheel assemblies that are locked, or to all wheel assemblies that are moving.

Abstract: A vehicle tracking system includes a wheel assembly containing sensor circuitry capable of sensing one or more types of conditions, such as wheel rotation, wheel vibration caused by skidding, and specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The wheel assembly may also include a brake mechanism. The wheel assemblies may be mounted on shopping carts and used to collect and monitor shopping cart status and location data via a wireless network. In one embodiment, the wheel assembly communicates via a wired or wireless connection with a handlebar mounted display unit of the cart.

Abstract: A navigation system uses a dead reckoning method to estimate an object's present position relative to one or more prior positions. In some embodiments, the dead reckoning method determines a change in position from the object's heading and speed during an elapsed time interval. In embodiments suitable for use with wheeled objects, the dead reckoning method determines the change in position by measuring the heading and the amount of wheel rotation. Some or all of the components of the navigation system may be disposed within a wheel, such as a wheel of a shopping cart.

Abstract: A power generation system for wheeled objects comprises a generator mechanically coupled to one or more of the object's wheels to convert wheel rotational energy into electrical energy. The power generation system may comprise an electrical storage device configured to store the electrical power produced by the generator. Power from the generator and/or the electrical storage device can be used to provide power to other electrical systems in or on the object. In certain embodiments, the electrical storage device comprises a bank of high-capacity capacitors connected in series. Some embodiments use a control circuit, for example, to regulate the charging and discharging of the capacitor bank and to provide suitable voltages for other systems. The power generation system may be disposed within an object's wheel, such as a wheel of a shopping cart.

Abstract: Various embodiments of a system for tracking and/or controlling wheeled vehicles (such as shopping carts), are described. In some embodiments, the system includes an RFID tag on the cart and an RFID reader device external to the cart. The tag can receive an interrogation signal from the reader and reply with a response signal. In various embodiments, the reader or a central control unit can perform various calculations based on the response signal, such as generating a received signal strength indication (RSSI) value. In some embodiments, based on the RSSI value or otherwise, the reader can send a command signal to the tag to take an action, such as to engage a brake mechanism.

Abstract: Various systems for monitoring wheeled vehicles (such as shopping carts) are disclosed. The system can include an RF antenna unit that is buried and is configured for bi-directional communication with the electronics on the cart. In some embodiments, the antenna comprises a plurality of transmitters, which can emit synchronized signals. In some embodiments, the antenna comprises a radiating cable, which can emit a signal along some, substantially all, or all of its length.

Abstract: A vehicle tracking system includes a wheel assembly containing sensor circuitry capable of sensing various types of conditions, such as specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The sensor circuitry is coupled to an RF transceiver, which may but need not be included within the wheel. The wheel may also include a brake mechanism. In one embodiment, the wheels are placed on shopping carts and are used to collect and monitor shopping cart status and location data via a wireless network. In some embodiments, the wheel assemblies detect that they have entered into particular zones by measuring received signal strengths of received command transmissions, and by comparing these measurements to thresholds that are used to define zone boundaries.

Abstract: A system is disclosed for tracking and controlling shopping carts and other types of human propelled vehicles. The system includes a wheel assembly that attaches to a cart. The wheel assembly includes a brake unit for inhibiting cart motion, and includes wireless communication circuitry. The wheel assembly is capable of activating the brake unit in response to one or more conditions, such as the receipt of an RF signal or command. In some embodiments, the system also includes a display unit that displays information to a user of the cart, including information regarding the cart's proximity to a lock zone in which the brake unit will become activated.

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.

Abstract: A vehicle tracking system includes a wheel containing sensor circuitry capable of sensing various types of conditions, such as wheel rotation, wheel vibration caused by skidding, and specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The sensor circuitry is coupled to an RF transceiver, which may but need not be included within the wheel. The wheel may also include a brake mechanism. In one embodiment, the wheels are placed on shopping carts and are used to collect and monitor shopping cart status and location data via a wireless network. The collected data may be used for various purposes, such as locking the wheel of an exiting cart if the customer has not paid, estimating numbers of queued carts, stopping wheel skid events that occur during mechanized cart retrieval, store planning, and providing location-based messaging to customers.

Abstract: Brake mechanisms for a wheel of non-motorized wheeled vehicle such as, e.g., a shopping cart, are described. In various embodiments, the brake mechanism can provide a variable amount of braking force or torque between zero and an amount sufficient to lock the wheel. In some embodiments, the brake mechanism includes a brake plate that is movable toward and away from a surface of the wheel hub along a direction parallel to the rotation axis of the wheel. The brake plate is configured not to rotate when the wheel and hub are rotating. Frictional engagement between the brake plate and the surface of the wheel hub provides the braking force. The brake plate and/or the surface of the wheel hub can include engagement features such as, e.g., protrusions and slots. In some embodiments, the brake mechanism fits entirely within the wheel.

Abstract: Various systems for detecting unauthorized exit events are disclosed. The systems can support a variety of different methods for assessing whether a customer is exiting the store without paying. The particular method or methods used may vary widely based on the types and the locations of the system components included in a given installation. For example, the system may be configured to detect that a cart has passed or is passing through a checkout lane.

Abstract: A navigation system uses a dead reckoning method to estimate an object's present position relative to one or more prior positions. In some embodiments, the dead reckoning method determines a change in position from the object's heading and speed during an elapsed time interval. In embodiments suitable for use with wheeled objects, the dead reckoning method determines the change in position by measuring the heading and the amount of wheel rotation. Some or all of the components of the navigation system may be disposed within a wheel, such as a wheel of a shopping cart.

Abstract: Examples of systems and methods for controlling or monitoring a fleet of human-propelled, wheeled carts and cart retrievers are described. The carts can be shopping carts at a retail facility, and the cart retrievers can be used to collect and return the shopping carts from a parking lot near the facility to a cart collection area. The carts or cart retrievers can monitor various status or usage parameters (such as retriever battery charge, cart collection trip speed, cart collection path or duration, etc.) and transmit the parameters to a central control unit. The central control unit can analyze and process the status or usage parameters. The system can provide a user interface for access to the status or usage parameters of the cart and cart retriever fleet.

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.

Abstract: A wheeled object (e.g., a human-propelled cart such as a shopping cart) can include a navigation system that uses dead reckoning to determine the position of the wheeled object. The navigation system can include a magnetometer and an accelerometer and may be disposed on a handle of the wheeled object. Examples of a system for calibrating the magnetometer and accelerometer during manufacture as well as during installation on the wheeled object are disclosed. The calibration includes calibrating for the soft iron distortion induced at the navigation system by the ferromagnetic shopping cart handle (or other ferromagnetic portions of the cart such as the frame) and hard iron distortions induced by nearby magnetic sources (e.g., a permanent magnet in an audio speaker). The calibration system can include a plurality of Helmholtz or Maxwell coils.

Abstract: A power generation system for wheeled objects comprises a generator mechanically coupled to one or more of the object's wheels to convert wheel rotational energy into electrical energy. The power generation system may comprise an electrical storage device configured to store the electrical power produced by the generator. Power from the generator and/or the electrical storage device can be used to provide power to other electrical systems in or on the object. In certain embodiments, the electrical storage device comprises a bank of high-capacity capacitors connected in series. Some embodiments use a control circuit, for example, to regulate the charging and discharging of the capacitor bank and to provide suitable voltages for other systems. The power generation system may be disposed within an object's wheel, such as a wheel of a shopping cart.

Abstract: A vehicle tracking system includes a wheel assembly containing sensor circuitry capable of sensing one or more types of conditions, such as wheel rotation, wheel vibration caused by skidding, and specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The wheel assembly may also include a brake mechanism. The wheel assemblies may be mounted on shopping carts and used to collect and monitor shopping cart status and location data via a wireless network.

Abstract: A vehicle tracking system includes a wheel containing sensor circuitry capable of sensing various types of conditions, such as wheel rotation, wheel vibration caused by skidding, and specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The sensor circuitry is coupled to an RF transceiver, which may but need not be included within the wheel. The wheel may also include a brake mechanism. In one embodiment, the wheels are placed on shopping carts and are used to collect and monitor shopping cart status and location data via a wireless network. The collected data may be used for various purposes, such as locking the wheel of an exiting cart if the customer has not paid, estimating numbers of queued carts, stopping wheel skid events that occur during mechanized cart retrieval, store planning, and providing location-based messaging to customers.

Abstract: Various loop antenna fixture embodiments are disclosed. The fixture can be configured to removably attach with other fixtures, thus changing the overall dimensions of an antenna wrapped around the periphery of the fixture or fixtures. Advantageously, after the antenna is wrapped around the fixture(s) to form an assembly, the entire assembly can be removed and installed without the requirement of removing the antenna from the fixture(s).