NZ533981A - Systems and apparatus for monitoring vehicles - Google Patents

Abstract

An apparatus for detecting tilting and rollover characteristics of a vehicle trailer or carriage is disclosed. The apparatus includes a measuring means, a computer control means, an audio indicator means and/or a visual display means for alerting a driver as to the rollover status of a vehicle and/or attached trailer unit. The measuring means includes a first accelerometer which is adapted to be mountable on an axle adjacent a left wheel hub and a second accelerometer adapted to be mountable on the axle adjacent a right wheel hub. The accelerometers are configured and arranged, in use, to obtain and forward any one or more lateral and/or vertical and/or longitudinal acceleration measurements to the computer control means. The control means includes a microprocessor suitably programmed and configured to receive the measurement signals in a suitable digital format, and from these signals determine the rollover state of the trailer being monitored, and provide the driver with an audio indicator and/or visual display means for alerting the driver as to the rollover status of the vehicle.

Description

oi -v.Z. 0 7 GOT 2005 tz n c n/ P D U W i~» ! 'J t— ^ ' Our ref: PTEK002 Patents Form No. 5 No. 533981 Dated: 7 July 2004 PATENTS ACT 1953 COMPLETE SPECIFICATION 40 VEHICLE ROLLOVER WARNING SYSTEM AND METHOD We, PTEK LIMITED, a New Zealand company, of PO Box 293, Paeroa, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the 45 method by which it is to be performed, to be particularly described in and by the following statement: 1 VEHICLE ROLLOVER WARNING SYSTEM AND METHOD TECHNICAL FIELD This invention relates to apparatus and systems for monitoring vehicles and trailers. More particularly, but not exclusively, the present invention relates to an apparatus for monitoring the stability of moving vehicles and/or trailers.

BACKGROUND ART Vehicles and trailers such as truck trailer units are at risk of rolling if not properly driven. Some trailer units, such as trailers laden with logs or other cargo such as milk, oil, chemical and petrol tankers, are at greater risk of rolling, particularly if driven by inexperienced drivers, due to the load and a high centre of gravity resulting in a lower static rollover threshold. The 15 rolling of heavy vehicles can result in extensive injury to persons and property, as well as environmental damage caused by spillages. Further, the rolling of trailer units can also cause traffic delays, particularly if a heavy trailer unit requires heavy lifting equipment to clear obstructions on the road.

A problem with truck trailer units is that it is common for drivers to haul a trailer unit having a higher payload than the cab, and a lower static rollover threshold. Further, given that the trailer is coupled to the cab in a way that feedback on the rolling state and behaviour of the trailer is not usually apparent except by visually assessing the trailer load through rear view mirrors, it can make it difficult for a driver to judge the lower static rollover threshold of the 25 trailer relative to the driver's cab. Given this situation, it makes it more difficult for an inexperienced driver to work out how best to haul a trailer unit with a heavy payload when there is minimal if not inadequate feedback to allow for a driver to adjust driving behaviour.

It is a non-limiting object of the invention to provide an apparatus for monitoring vehicle and 30 trailer units that overcome at least some of the abovementioned problems, or at least to provide the public with a useful choice. 2 It is a further non-limiting object of the invention to provide a system for monitoring vehicle and trailer units that overcome at least some of the abovementioned problems, or at least to provide the public with a useful choice.

It is a further non-limiting object of the invention to provide a computer controlled method of monitoring the vehicle rollover status that overcome at least some of the abovementioned problems, or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION According to a broad aspect of the invention there is provided an apparatus for detecting tilting and rollover characteristics of a vehicle trailer or carriage, the apparatus including a measuring means, a computer control means and an audio indicator means and/or visual 15 display means for alerting a driver as to the rollover status of a vehicle and/or attached trailer unit, the measuring means including a first accelerometer adapted to be mountable on an axle adjacent a left wheel hub and a second accelerometer adapted to be mountable on the axle adjacent a right wheel hub, the accelerometers being configured and arranged, in use, to obtain and forward any one or more lateral and/or vertical and/or longitudinal acceleration 20 measurements to the computer control means, the control means including a microprocessor suitably programmed and configured to receive the measurement signals in a suitable digital format and determine the rollover state of the trailer being monitored and to provide a driver with an audio indicator means and/or visual display means for alerting a driver as to the rollover status of a vehicle.

Optionally, the measuring means includes three triple axis accelerometers whereby the first accelerometer is adapted to be mountable adjacent the left wheel hub, the second accelerometer is adapted to be mountable adjacent the right wheel hub and a third accelerometer is adapted to be mountable adjacent the middle of the axle between the left and 30 right wheel hubs. 3 Desirably the control means includes a microprocessor means configured and programmed to receive measured signals from the measuring means and process such signals to determine the rollover status of the trailer or carriage being monitored.

Preferably the control means includes digital storage means being adapted to store data received from the measuring means, and any processed data. Desirably the control means includes a data logging means, and being adapted with a transmitter means to transmit data to a remote location.

Desirably the display means includes a bar graph representing the extent of rollover of the vehicle and/or trailer being monitored.

According to a second broad aspect of the invention there is provided a method for monitoring rollover effects on vehicles and/or trailer units using the apparatus according to 15 any one of claims 1 to 6, the method comprising the steps of: a.) obtaining data from the measuring means being at least two accelerometers and forwarding measured data to a control means in a suitable digital format; b.) determining the rollover risk of the vehicle and/or trailer units being 20 monitored; and c.) providing a visual and/or audio indicator means to inform or alert a driver as to the rollover status of the vehicle and/or trailer unit.

Desirably the data received by the control means is stored in a storage device associated with 25 the control means. Advantageously the logged data is transferable to a remote location using a transmitter means.

According to a third broad aspect of the invention there is provided a computer controlled process for determining the rollover risks on vehicle trailer and/or carriage units, the computer 30 program comprising the steps of: A.) getting measured acceleration data from at least two accelerometers, a first accelerometer adapted to be mountable on an axle adjacent a left wheel hub and a 4 second accelerometer adapted to be mountable on the axle adjacent a right wheel hub; B.) converting the inputted data to g values using a predetermined calibration constant; C.) comparing the left side and the right side lateral acceleration values, and if the values are similar then the program will reset to step A, and if the values are dissimilar, the program will move to step D; D.) determining the rollover risk of the vehicle and/or trailer units being monitored by comparing the sets of vertical acceleration values with a predetermined rollover threshold value, and if the threshold value is exceeded; E.) triggering an audio and/or visual indicator means to alert a driver that the predetermined rollover threshold of trailer has been exceeded.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred and alternative embodiments of the invention will now be illustrated, by way of example only, with reference to the accompanying drawings in which: Figure 1: Shows a block diagram of main components of the apparatus according to a preferred embodiment of the invention; Figure 2: Shows a diagrammatic view of the arrangement of components on a truck and trailer unit; Figure 3: Shows a flow chart of steps of the computer controlled method of processing and monitoring the rollover risk or status of the vehicle; and Figure 4: Shows a display means of the rollover status of the trailer.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to figure 1, a block diagram of main components of the vehicle rollover warning apparatus, generally referred to as 1, according to a preferred embodiment of the invention, is illustrated.

Vehicle rollover is a complex event, heavily influenced by driver and road characteristics as well as vehicle properties. Vehicle rollover generally occurs when a vehicle turns at an excessive speed and given factors such as, for example, the suspension roll stiffness of the vehicle, the centre of gravity and load height and mass of the vehicle, axle width, and the left side to right side load balance effected by the road surface. When a moving vehicle such as a 10 truck commences a cornering action, a lateral acceleration is created and a roll moment about a roll axis occurs. It is seen that if the roll moment passes a static rollover threshold, wheel liftoff can occur. If the roll moment continues, vehicle rollover will occur.

It is seen then that the larger the lateral acceleration, the greater the roll moment, and the 15 higher the centre of gravity, the greater the roll moment will be with a vehicle. These characteristics are particularly evident in heavy truck and trailer units that often carry heavy axle loads, and with many logging trucks that are heavily laden with logs resulting in a high centre of gravity for the trailer unit. This increases the risk of rollover due to a high centre of gravity causing a roll moment of inertia for a given lateral acceleration. This means that 20 drivers of vehicles hauling trailer units with a load bearing a high centre of gravity are at increased risk of encountering vehicle rollover. In such situations a rollover monitoring and warning system is considered to be useful in providing feedback signals as to the rollover risks of the trailer unit being hauled behind the truck cab.

The apparatus 1 includes a vehicle acceleration measuring means 2 preferably in the form of durable and suitable sensing, measuring and/or detecting means. The measuring means in this non-limiting preferred embodiment desirably includes at least one accelerometer adapted to be fitted to a vehicle or trailer unit, preferably about the axle, and more desirably can be fitted adjacent the wheel hub of the vehicle or trailer unit. Desirably triple axis accelerometers may 30 be used to obtain lateral, longitudinal and vertical acceleration measurements, although double axis accelerometers or selectively using some of the triple axis acceleration measurements from different accelerometers may be applied. 6 For simplicity of description references to vehicles and/or trailer units will hereinafter refer to trailers although it will be appreciated that the apparatus can be adapted to monitor any vehicle or unit being driven on wheels whereby rollover is possible. For example, the apparatus of the invention may be adapted to monitor rollover dangers with racing cars or 5 train carriages.

The measuring means 2 can include a variety of sensing and measuring devices, and can include for example, but not limited to, strain gauges, shock sensors, pressure transducers, accelerometers, speedometers, angular rate sensors or gyros or otherwise such as an axle load weighing means. The angular rate sensors can measure the angular pitch rate, the roll rate and the yaw rate. An onboard weighing means to measure the axle load could be utilised in some embodiments of the invention.

In this non-limiting embodiment three triple axis accelerometers are desirably mounted in 15 positions that are most sensitive to changes in inclination and are desirably mounted on the vehicle or trailer axle. It will be appreciated that although using three triple axis accelerometers can provide up to nine channels of measured data and the system of the invention is configured to process and data log these channels of data, in practice less channels and acceleration measurements may be obtained to detect wheel liftoff and to 20 provide the necessary feedback warnings to a driver.

As seen in figure 2, a first accelerometer 12 is adapted to be mounted adjacent the left side wheel hub, a second accelerometer 11 is advantageously mounted on the axle adjacent the right side wheel hub, and the third accelerometer 10 is desirably mounted adjacent the centre of the axle.

It will be appreciated in an alternative embodiment that a triple axis accelerometer mounted on the left side of the axle and a triple axis accelerometer mounted on the right side of the axle would provide six readings and six channels of data, and such feedback would provide a 30 certain level of feedback warning on a rollover event taking place in accordance with the invention. 7 The accelerometers 2 can be integrated circuits, and each integrated circuit ("IC") may provide up to three or more accelerometers. The accelerometers 2 can be configured and arranged to measure static g forces (gravity) and can also measure dynamic forces. The accelerometers 2 are preferably IC's mounted on a suitable printed circuit board ("PCB"), and 5 preferably measure static g forces as a voltage/g and such analog measurements are forwarded to a signal processing means 3.

The signal processing means 3 preferably includes suitable amplifier and filtering elements and associated circuitry to provide a filtered analog signal that is fed to the input of an 10 analogue to digital converter adapted to convert the analogue input measurements to a digital output signal. The signal processing means 3 can be mounted at the trailer axle or can be integral with a microprocessor control means 4. The analogue to digital converter preferably includes an adjustable bit rate, and the sampling rate may be set at any desirable and suitable data transfer rate and may be between 1Hz to 50Hz and more preferably be about 10Hz with 15 digital filtering at about 1Hz to 5Hz with a resolution at 10 bits per second or higher.

It is envisaged that the signal processing means 3 may be optionally mounted on the same printed circuit board as the accelerometers 2 and arranged about a trailer axle 9 (as seen in figure 2). The signal processing means 3 receives measurement readings from each of the 20 accelerometers 2 and processes, converts and forwards such output digital data to the digital processing and control means 4. Any suitable data transfer means can be employed as required, whether wired or wireless, and in the case of wireless transfers any other suitable circuitry and hardware and computer software can be employed to enable the output signals to be transferred reliably to the computer control means 4.

Twisted wired cables used for instrument wiring is preferably used. Advantageously the twisted pairs of wires are preferably shielded overall to reduce noise and interference with the transfer of measured signals, and in this application is a preferred means of interconnecting components of the invention. Termination of cables is preferably by way of glands, sealed 30 boxes, rail or PCB mounted connector blocks, as required. More particularly, twisted pairs are used for balanced two wire serial data with an RS485 or similar industrial serial protocol. In this preferred embodiment a serial cable adaptor may be employed to transfer data via an output RS232 serial cable adapted to feed into a USB port in the computer control means 4. 8 The computer control means 4 can be any suitable microprocessor or computer controller means and is desirably a compact computer suitably programmed and configured with the computer controlled method of the invention to carrying out the processing steps of the 5 invention to enable suitable feedback signals on the rollover risks of the trailer being hauled. Although a compact notebook computer running a software application program may be used, an ultra compact computer running optionally embedded software, may be mountable to a vehicle dashboard in accordance with an aspect of the invention. More preferably, a computer means with a display run by embedded computer software for carrying out the steps 10 of the invention could be employed. This computer means would include all the essential hardware components for a computer including a data storage device, a memory means, a processor means, input/output devices including a keyboard, a display means and a power supply.

The data storage device of the computer means 4 is desirably configured to allow data logging of digital signals that can be collected and later used for subsequent transfer and analysis, as required. It will be appreciated that recorded data can be useful should the vehicle be involved in a rollover incident to assess the movements of the trailer vehicle and driver inputs.

The computer means 4 can be located in any convenient position anywhere between the measuring means and the display means and more desirably is physically integrated with a display means 5 and therefore is desirably mounted about the dashboard area or cab of a truck or vehicle with the display being within the range of vision of the driver whilst the driver is operating the vehicle trailer. It is envisaged that a driver of a truck and trailer unit may 25 receive suitably processed feedback signals of the rollover status of the trailer from the control means 4 in the form of a display means 5 and/or an audio warning means 6. Furthermore, the computer means 4 can be adapted with a transmitter means allowing, in use, data to be transmitted to a remote monitoring station, or both. The measured data can also be logged by the computer control means 4 in a data storage device to be later downloaded for use and 30 analysis, as required.

Although it is envisaged that remote monitoring of trailers for rollover dangers and other readings on the status of a trailer can be employed in accordance with the invention, this non- 9 limiting embodiment is directed to the use of measured and processed readings to be monitored by a driver of the trailer by use of suitable audio indicator means and/or visual display means 5 for, inter alia, alerting a driver as to the rollover risk of the trailer being hauled.

It is considered that a driver of milk or oil tankers or logging trucks, may well find the invention particularly useful in the early detection of trailer rollover.

The computer means 4 can include a data input means preferably in the form of a keypad or keyboard or the like to enable a user to input any desirable information such as the load length of the trailer and the weight of the load. This data can be then used to calculate the load height that can be used by the computer means 4 when determining the rollover status of the trailer. That is, the rollover status includes a determination of the load height and the lateral acceleration characteristics of the axle and wheels that can provide a determination of rollover risk. Any other suitable and convenient method of calculating load height may be employed.

Referring now to figure 2, a diagrammatic view of the arrangement of measurement means and physical arrangement of main components on a trailer axle, is illustrated.

A trailer axle 9 desirably is provided with three double or triple axis accelerometers 10, 11, 12 mounted thereto in an arrangement as shown. Double axis accelerometers may be used with other suitable types of sensors such as strain gauges and/or shock sensors as required or desired.

In one non-limiting embodiment, the accelerometers 10, 11, 12 each may be configured and arranged such that the left wheel hub accelerometer 12 and the right wheel hub accelerometer 11 located about an axle take lateral and vertical acceleration measurements and a middle accelerometer 10 can take vertical acceleration measurements and longitudinal readings for braking and acceleration.

In an alternative embodiment it may be considered that only the left and right axle accelerometers need to used to obtain certain acceleration measurements. The right accelerometer 11 may measure vertical and longitudinal accelerations and the left accelerometer 12 may measure vertical and lateral accelerations, the combination of which can provide the computer means with a certain amount of data to determine wheel liftoff and provide driver feedback of a risk of rollover to allow for an adjustment in the driving manoeuvre taking place to avert a rollover event.

The signal processing means 13 (similar to the signal processing means 3 of figure 1) can be incorporated in the same casing as the accelerometers 10, 11, 12 and the data output processed is desirably then transferred via suitable data cabling 15 to a digital processing means and associated display means 14.

Referring now to figure 3, a flow chart of broad processing steps of the computer controlled process for determining the rollover status of the trailer being monitored, is illustrated.

The computer means 4 is advantageously configured to run by a suitable computer software 15 program for the purpose, inter alia, of receiving inputted measured data that has been converted to digital signals by the signal processing means 3 and determining an output value that is adapted for display to represent the rollover status of the trailer or vehicle being monitored, and for triggering the audio indicator means 6. Other functions for the software such as, for example, data logging configuration, control, and retrieval from a database, is 20 envisaged. The computer software program is desirably windows based, and can provide a screen display of the digital g acceleration measurements along with the option of configuring graph plots of acceleration measurements over time to show characteristics of the trailer unit being monitored. The data may also be exported using .txt (text) and/or .csv (comma separated values) comma delimited formats.

In accordance with the software processing steps the first preliminary step i. is to set up user preferences desirably including the data transfer rate which can desirably be set to operate at between about 10Hz to about 30Hz, data logging options for inputted digital signals from any one or more of the accelerations measured from the accelerometers 10, 11, 12 and inputting 30 any values to increase the accuracy of determining the static rollover threshold and critical rollover indicators for the vehicle being monitored. Lateral setpoints can be inputted to set the audio and/or visual warning signal thresholds. These may be set at any desirable and suitable value, and more particularly are preferably set between substantially about 0.3g and 0.6g. 11 A static rollover threshold value may desirably be set and this may be at any suitable rollover value and more preferably is substantially somewhere between 0.25 and 0.85g. This threshold value can vary depending on factors such as, for example, the load mass, load 5 height, suspension roll stiffness, left/right load balance and trailer structural factors.

Optionally the form of display of measured g forces in a table form and/or a bar graph or other such graphical indicator of the g forces for displaying wheel liftoff and the risk of vehicle rollover can be selected.

In some instances a driver may prefer feedback on the rolling state of the trailer in the form of an audio signal or alarm triggering if wheel liftoff has occurred and/or when a preset critical high g threshold has occurred if the trailer is close to rolling over.

When user preferences are complete, the program can be started by opening the serial port connection to start receiving suitably converted measurement signals that have already passed through the analogue to digital converter of the signal processing means 3 and associated filtering. In accordance with step a. the program will get data fed from the signal processing means 3 to a USB port on the computer means 4. This inputted data, in accordance with step 20 b. is then converted to g values by multiplying the values by a predetermined calibration constant. It is seen that this calibration constant value will be obtained from the accelerator feeding the measurements and g is known to represent acceleration measured in gravities (where lg=9.81 m/s2). In accordance with step c. the outputted values are then fed into an algorithm that recognises left side or right side cornering characteristics by comparing the 25 lateral acceleration values. If the left and right lateral acceleration values are substantially similar, and the values may be about +lg the data is desirably logged and will contribute to the calculation of a running mean average value and will be used to calculate a statistical standard deviation value as used in the formula below. The program will then reset to step a. and get the next set of data values.

If in step c. the left and right lateral acceleration values are substantially dissimilar then the program accepts that the trailer is moving through a corner and that the outer wheel and side is being subjected to a different g forces than the inside wheel and side. At this point the 12 program will move to step d. and process the vertical acceleration values in order to detect wheel liftoff. This is achieved by the program comparing the sets of vertical accelerations with a threshold value that is calculated in each iteration by the following formula: Vertical threshold value = mean average value + (3*standard deviations) If it is determined that the vertical acceleration exceeds the preset threshold the program, in step e. will preferably trigger an audio alarm to warn the driver of a rollover danger with the trailer.

Alternatively, program step d. may compare the lateral acceleration values against preset threshold values that were entered as the left side and right side lateral setpoints, and, if a setpoint value is exceeded, then the program will trigger an audible warning.

These values can also be indicated in the display graphs as a further warning indicator offered to the driver.

Once step e. is passed, the program resets to step a. and further data is processed in accordance with the invention.

Such output values can be advantageously plotted on the display means 5 for quick and easy reference by a driver or person monitoring the rollover risk of the trailer unit. It is envisaged that the application software program can allow output data to be displayed on the display means 5 in real time, and can allow pop up indicators and warning alerts when suspected events are determined.

The computer means 4 also desirably includes a data storage means that can also be used data logging measured data for future analysis. Data logging can enable analysis of trailer and driver characteristics from the start to the end of the journey being monitored. Further, in the 30 event of a rollover occurring, such data can be reviewed to determine the cause of such rollover event occurring. Data logging may desirably also record the time of various events from the start to finish of the journey. 13 The computer means 4 is preferably configured to receive, process, storage and display other desirable information on a vehicle's performance such as GPS location, speed, distance travelled, time, estimated tilting measurements and any other desirable inputted measurements and images.

The computer software program can also be configured to include graph plotting and printing options such that a spreadsheet of data, and/or graph plotting routines can be executed.

Referring now to figure 4, a display means, including a bar graph 20, representing degrees of 10 tilt and rollover risk, is illustrated.

The bar graph 20 may well be a liquid crystal display or any other known type of display means, and the degree of tilt and rollover risk may be graphically represented by bars, with two sets of indicators, the left side indicator representing the rollover risk with the left side of 15 the trailer lifting off, and the right side indicator representing the rollover risk with the right side of the trailer lifting off. The risk indicators can be colour coded such that green bars (G) illuminating indicate normal operating parameters, orange bars (O) illuminating indicate borderline operating parameters, and red bars (R) illuminating indicating critical operating parameters.

In particular and as shown, the left bar graph will show the status of the left side of the vehicle or trailer unit and the right side will show the status of the right side of the vehicle or trailer unit. The letters at the bottom illustrate that the bars can be desirably colour coded for easy reference. The usual or acceptable degree of tilt measured or detected will be displayed by 25 illuminating any one or more of the five green bars (marked G) on the left and/or right side bar graphs. The X may be an illustration of the rear end of the trailer unit being monitored. If the degree of tilt increases to an unreasonable or undesirable degree the orange bars (marked O) may also illuminate as an alert to the driver. An audio tone may also desirably be activated according to an aspect of the invention. If the degree of tilt is at a critical moment or 30 very close to it, the red bars may illuminate (marked R) and a different audio tone may be activated by the control means representing a critical degree of tilt that may be at the point of rollover of the trailer unit or vehicle. 14 It is envisaged that the control means located in the cab of the vehicle or about the driver responsible for a load, can be provided by a small industrial computer or personal digital assistant (PDA) or equivalent. Advantageously the computer software program can conveniently run on a standard software platform provided by the PDA. That is, the computer 5 software program of the invention may be configured and arranged to run on any known computer operating platform provided with many PDA's. These computer devices are useful as they are small and portable, and can be adapted to run suitable windows based applications as that envisaged with the software of the current invention.

It will be appreciated that the invention may be associated with engine control systems such that automatic governing of speed and possibly direction can be incorporated with the task of reducing the risk of trailer rollover.

It will be appreciated that the invention includes a suitable power supply, and such supply is 15 adapted to power the control means and other components of the invention.

It will be appreciated that materials used for components of the invention include any suitable and durable materials, for example only but not limited to, timber, metal, plastics materials, fabrics, rubber, glass or any combination thereof.

Wherein the aforegoing reference has been made to integers or components having known equivalents, then such equivalents are herein incorporated as if individually set forth. Accordingly, it will be appreciated that changes may be made to the above described embodiments of the invention without departing from the principles taught herein.

It is to be understood that the above description is intended to be illustrative, and not restrictive. Additional advantages of the present invention will become apparent for those skilled in the art after considering the principles in particular form as discussed and illustrated. Thus, it will be understood that the invention is not limited to the particular embodiments 30 described or illustrated, but is intended to cover all alterations or modifications which are within the scope of the appended claims.

Claims (4)

Claims:

1. An apparatus for detecting tilting and rollover characteristics of a vehicle trailer or carriage, the apparatus including a measuring means, a computer control means and 5 an audio indicator means and/or visual display means for alerting a driver as to the rollover status of a vehicle and/or attached trailer unit, the measuring means including a first accelerometer adapted to be mountable on an axle adjacent a left wheel hub and a second accelerometer adapted to be mountable on the axle adjacent a right wheel hub, the accelerometers being configured and arranged, in use, to obtain and forward 10 any one or more lateral and/or vertical and/or longitudinal acceleration measurements to the computer control means, the control means including a microprocessor suitably programmed and configured to receive the measurement signals in a suitable digital format and determine the rollover state of the trailer being monitored and to provide a driver with an audio indicator means and/or visual display means for alerting a driver 15 as to the rollover status of a vehicle.

2. An apparatus according to claim 1 wherein the measuring means includes three triple axis accelerometers whereby the first accelerometer is adapted to be mountable adjacent the left wheel hub, the second accelerometer is adapted to be mountable 20 adjacent the right wheel hub and a third accelerometer is adapted to be mountable adjacent the middle of the axle between the left and right wheel hubs.

3. An apparatus according to claim 1 or claim 2 wherein the control means includes a microprocessor means configured and programmed to receive measured signals from 25 the measuring means and process such signals to determine the rollover status of the trailer or carriage being monitored.

4. An apparatus according to any one of the preceding claims wherein the control means includes digital storage means being adapted to store data received from the 30 measuring means, and any processed data. 16 An apparatus according to any one of the preceding claims wherein the control means includes a data logging means, and being adapted with a transmitter means to transmit data to a remote location. An apparatus according to any one of the preceding claims wherein the display means includes a bar graph representing the extent of rollover of the vehicle and/or trailer being monitored. A method for monitoring rollover effects on vehicles and/or trailer units using the apparatus according to any one of claims 1 to 6, the method comprising the steps of: a. obtaining data from the measuring means being at least two accelerometers and forwarding measured data to a control means in a suitable digital format; b. determining the rollover risk of the vehicle and/or trailer units being monitored; and c. providing a visual and/or audio indicator means to inform or alert a driver as to the rollover status of the vehicle and/or trailer unit. A method according to claim 7 wherein the data received by the control means is stored in a storage device associated with the control means. A method according to claim 7 wherein logged data is transferable to a remote location using a transmitter means. A computer controlled process for determining the rollover risks on vehicle trailer and/or carriage units, the computer program comprising the steps of: A. getting measured acceleration data from at least two accelerometers, a first accelerometer adapted to be mountable on an axle adjacent a left wheel hub and a second accelerometer adapted to be mountable on the axle adjacent a right wheel hub; B. converting the inputted data to g values using a predetermined calibration constant; 17 10 11. 12. 15 13. C. comparing the left side and the right side lateral acceleration values, and if the values are similar then the program will reset to step A, and if the values are dissimilar, the program will move to step D; D. determining the rollover risk of the vehicle and/or trailer units being monitored by comparing the sets of vertical acceleration values with a predetermined rollover threshold value, and if the threshold value is exceeded; and E. triggering an audio and/or visual indicator means to alert a driver that the predetermined rollover threshold of trailer has been exceeded. An apparatus for detecting tilting and rollover characteristics of a vehicle substantially as herein described with reference to any one of the accompanying drawings. A method according to claim 7 substantially as herein described. A computer controlled method according to claim 10 substantially as herein described. PTEK LIMITED 20 By their Attorneys SCHUCH & COMPANY^ per: 18