Patent Description:
The invention can be applied in vehicle and heavy-duty vehicles, such as trucks, buses and construction equipment. Although the invention will be described with respect to a payload monitoring device for a mining truck, the invention is not restricted to this particular vehicle, but may also be used in other types of vehicles.

A mining vehicle generally comprises a trailer configured to transport a payload. The trailer may be supported by support members. Such support members may comprise suspension members. Typically, the force, exerted by the payload weight, is distributed to the suspension members.

Overloading, under loading or uneven loading of vehicles can deteriorate suspension members, drive train or other parts affected by weight. In order to prevent such a deterioration, it is desirable to know the weight of a payload.

Different payload measurement systems and methods are known.

Typically, for a vehicle with a tipping trailer, payload measurement systems utilize sensors that measure hydraulic pressures present in tilt cylinders used for lifting the trailer up and down. However, one problem with such payload measurement systems is that they fail to take into account the impact that the tilt cylinders have on supporting the payload. The contribution of the tilt cylinders in supporting the payload in the trailer varies based on the tilt position of the trailer. Therefore, the estimate of the payload weight can be inaccurate.

A solution is to measure angular position of the trailer. More precisely, the payload measurement system is configured to estimate weight of a payload in a trailer based on the pressure data, the angular position data and predetermined physical parameters relating to a tilt linkage and lift linkage that are useable to characterize an effect of a portion of the payload that is supported by a tilt cylinder assembly. Such measurement systems can be used on vehicle with tipping trailer only.

Moreover, it is known to utilize sensors that measure air pressures present in suspension cylinders, and a device for measuring vehicle orientation with regard to the ground, such as an inclinometer. The device for measuring vehicle orientation enables to compensate for sloped surfaces on which the vehicle drives. Such measurement systems are costly and can be used on vehicle with air suspension only.

While systems for monitoring payload exist, they are not fully satisfactory. Indeed, they are not suitable for all types of vehicles, and they are costly.

<CIT> discloses a vehicle load measuring device having a sensing member for measuring the load of the vehicle by detecting a strain on the slide plate.

It is therefore desirable to provide an improved payload monitoring system that is simple and adaptable to all types of vehicles, in order to prevent suspension deterioration, and therefore reduce warranty costs.

An object of the invention is to provide a system for monitoring payload that solve at least the previous problem of the prior art.

According to a first aspect of the invention, the object is achieved by a system according to claim <NUM>.

By the provision of a payload monitoring system, which comprises a piezo-resistive pressure sensor, the payload can be easily and accurately measured, thanks to an onboard system, which can be used to measure any payload, in any vehicle.

Indeed, the piezo resistive pressure sensor is electrically polarized when subjected to the mechanical strain of the axle beam as a result of a payload. The mechanical strain of the surface is advantageously uniform and proportional to the payload, and therefore the amount of change in electrical resistance is proportional to the payload.

For instance, the system can be used to measure the weight of a load in a trailer of a truck, or the weight of a driver on a seat of a vehicle. Therefore, the system can enable to provide the vehicle with adaptive suspension depending on the weight of the payload.

The system is an electromechanical system.

The system is advantageously autonomous.

According to one embodiment, the at least one wireless transmitter comprises a wired communication channel between the piezo-resistive pressure sensor, the transceiver and the battery unit.

According to one embodiment, the piezo-resistive pressure sensor is configured to emit an electrical signal in response to the mechanical strain of the axle beam, and the transceiver is configured to receive the electrical signal in order to emit the wireless signal.

According to one embodiment, the piezo-resistive pressure sensor comprises silicon material.

According to the invention, the battery unit comprises a switch configured to switch on the battery unit when the vehicle is moving.

According to one embodiment, the system comprises an amplifier configured to amplify the wireless signal emitted by the at least one wireless transmitter.

According to one embodiment, the wireless receiver comprises a controller configured to transform the wireless signal into a digital signal.

According to one embodiment, the at least one wireless transmitter comprises at least one fastening tip configured to enable the at least one wireless transmitter to be attached to the axle beam.

According to one embodiment, the at least one wireless transmitter comprises two fastening tips configured to enable the at least one wireless transmitter to be attached to the axle beam.

According to one embodiment, the wireless signal is a WiFi or Bluetooth signal.

According to one embodiment, the system comprises two wireless transmitters.

According to a second aspect of the invention, the object is achieved by a vehicle according to claim <NUM>.

According to one embodiment, the vehicle comprises an axle beam, the at least one wireless transmitter being attached to the axle beam.

According to one embodiment, the axle beam comprises a housing for the at least one transmitter.

According to one embodiment, the at least one fastening tip is integral with the axle beam.

According to one embodiment, the at least one wireless transmitter is fastened onto the at least one fastening tip by screws.

According to one embodiment, the at least one wireless transmitter is integral with the axle beam.

In this document, "vehicle" means any of a vehicle used for transporting items and goods, such as a mining truck, and a vehicle for transporting people, such as a car, a van, or a bus or a trailer.

<FIG> shows a vehicle <NUM> comprising a system <NUM> for monitoring payload of the vehicle <NUM>. The system <NUM> measures the weight of a payload of the vehicle <NUM>.

The system <NUM> for monitoring payload comprises at least one wireless transmitter <NUM>, and for example can include two wireless transmitters <NUM>. The at least one wireless transmitter <NUM> is configured to be attached to an axle beam <NUM> of the vehicle <NUM> and to emit a wireless signal in response to a mechanical strain of the axle beam <NUM> which occurs upon a payload put on the vehicle <NUM>.

The system <NUM> for monitoring payload comprises a wireless receiver <NUM> configured to receive the wireless signal from the at least one wireless transmitter <NUM>.

The wireless receiver <NUM> can be configured to be placed inside the vehicle <NUM>. In the example where the vehicle <NUM> is a truck, such as a mining truck, the wireless receiver <NUM> can be configured to be placed within the cab roof of the mining truck. Therefore, the system <NUM> is configured to be an onboard system. Thus the weight of the payload can be read at any time.

The system <NUM> for monitoring payload can comprise an amplifier <NUM> configured to amplify the wireless signal emitted by the at least one wireless transmitter <NUM>.

The wireless receiver <NUM> can comprise a controller <NUM> configured to transform the wireless signal into a digital signal. The digital signal corresponds to the weight of the payload.

The controller <NUM> can provide calibration of the mechanical strain according to the payload.

The wireless receiver <NUM> can comprise a display <NUM> where the digital signal is displayed.

More precisely, <FIG> and <FIG> show that the at least one wireless transmitter <NUM> comprises a piezo-resistive pressure sensor <NUM>, a battery unit <NUM> and a transceiver <NUM>. The piezo-resistive pressure sensor <NUM>, the battery unit <NUM> and the transceiver <NUM> are encapsulated in an insulating casing <NUM> for protection purposes.

The piezo-resistive pressure sensor <NUM> is configured to emit an electrical signal in response to a mechanical strain of the axle beam <NUM> of the vehicle <NUM>.

The piezo resistive pressure sensor <NUM> is electrically polarized when subjected to the mechanical strain of the axle beam <NUM> as a result of a payload. The mechanical strain of the axle beam <NUM> is advantageously uniform and proportional to the payload, and therefore the amount of change in electrical resistance is proportional to the payload.

The at least one wireless transmitter <NUM> is configured to be attached to the axle beam <NUM> like a coating. The mechanical strain produced in the axle beam is transferred to the piezo resistive pressure sensor <NUM> and an electrical output is achieved.

The piezo-resistive pressure sensor <NUM> can comprise silicon material.

The battery unit <NUM> comprises a switch <NUM> configured to switch on the battery unit <NUM> when the vehicle <NUM> is moving.

The at least one wireless transmitter <NUM> can comprises a wired communication channel <NUM> between the piezo-resistive pressure sensor <NUM>, the transceiver <NUM> and the battery unit <NUM>.

The piezo-resistive pressure sensor <NUM> is configured to emit an electrical signal in response to the mechanical strain of the axle beam <NUM>. The transceiver <NUM> is configured to receive the electrical signal and to emit the wireless signal.

The at least one wireless transmitter <NUM> can be configured to be attached to the axle beam <NUM> by screws <NUM> or any suitable connecting means.

The at least one wireless transmitter <NUM> can comprise at least one fastening bracket <NUM> configured to enable the at least one wireless transmitter <NUM> to be attached to the axle beam <NUM>. The at least one wireless transmitter <NUM> can be attached to the at least one fastening bracket <NUM> by screws <NUM>. The at least one fastening bracket <NUM> can be configured to be attached to the axle beam <NUM>, for instance by screws.

The at least one wireless transmitter <NUM> can preferably comprise two fastening brackets 32A, 32B configured to rigidly attach the at least one wireless transmitter <NUM> to the axle beam <NUM>. The fastening brackets 32A, 32B can be placed at a first and a second end of the at least one wireless transmitter <NUM>.

The at least one fastening bracket <NUM> can be integral with the axle beam <NUM>. The at least one wireless transmitter <NUM> can be plugged inside the at least one fastening bracket <NUM>.

The at least one wireless transmitter <NUM> is a removable transmitter. The at least one wireless transmitter <NUM> can be removed from the axle beam <NUM> and refitted to the axle beam <NUM>, for maintenance purpose. The system <NUM> for monitoring payload provides an opportunity for modularity.

The at least one wireless transmitter <NUM> can be water proof, dust proof and/or EMI compatible.

The wireless signal can be a WiFi or Bluetooth signal.

The system <NUM> for monitoring payload is therefore a plug and play system. The system <NUM> is autonomous and does not require a specific wiring.

The system <NUM> is configured to alert a customer while overloading the vehicle. The system <NUM> can also keep record of abusive usage of the vehicle.

Claim 1:
A system (<NUM>) for monitoring payload of a vehicle (<NUM>), characterized in that it comprises:
- at least one wireless transmitter (<NUM>) comprising a piezo-resistive pressure sensor (<NUM>), a transceiver (<NUM>) and a battery unit (<NUM>), encapsulated in an insulating casing (<NUM>), the battery unit (<NUM>) comprising a switch (<NUM>) configured to switch on the battery unit (<NUM>) when the vehicle (<NUM>) is moving, the at least one wireless transmitter (<NUM>) being configured to be attached to an axle beam (<NUM>) of the vehicle (<NUM>) and to emit a wireless signal in response to a mechanical strain of the axle beam (<NUM>),
- a wireless receiver (<NUM>) configured to receive the wireless signal from the at least one wireless transmitter (<NUM>).