GB2540488A

GB2540488A - Killswitch

Info

Publication number: GB2540488A
Application number: GB1616693.6A
Authority: GB
Inventors: Boys Jonathan; Smart David
Original assignee: JBT MARINE
Current assignee: JBT MARINE
Priority date: 2009-06-25
Filing date: 2009-06-25
Publication date: 2017-01-18
Also published as: GB2540488B; WO2010149979A3; GB201616694D0; GB2471314B; GB201616693D0; GB2471314A; GB2540489A; GB2540489B; GB0910990D0; WO2010149979A2

Abstract

An ultrasonic killswitch system for an operator-controlled powered apparatus such as a boat includes ultrasonic sensor units for scanning a search area to detect the presence or absence of objects, including the operator (driver, pilot), in the search area. A controller is programmed to generate a killswitch signal in response to a reading or signal from the sensor units indicative of the absence of the operator within the search area which automatically cuts the power to the apparatus. A calibration mode uses multiple scanning operations to identify permanent and non-permanent objects within the search area, by creating a virtual map of reflective responses to ultrasonic pulses from the sensor units; subsequent returns are compared with this. Each sensor unit has a piezoelectric transmitter and a piezoelectric receiver and a single input/output cable for communication with the controller.

Description

Killswitch

The present invention relates to a power cut off system, more particularly, but not exclusively to a killswitch system for a vehicle or machine, e.g. for cutting power to the motor or engine of a water craft. The invention also relates to an operator detection system.

It is common for a powered boat to include a killswitch by means of which the boat’s engine can be cut and the vessel immobilised in the event that the operator loses control of the vehicle or is thrown overboard. Typically, the operator will be connected to the killswitch by a tether or “kill cord” (e.g. attached to the operator’s body or life jacket). In the event that the operator is thrown overboard, the tether will pull on or disconnect from the killswitch and thereby activate the power cut-off function and shut down the boat’s engine.

Conventional killswitch systems of the kind referred to above rely on the operator wearing the tether at all times when controlling the vehicle, as well as appropriate connection between the tether and the killswitch etc.

It is an object of the invention to provide a kill switch system which addresses these issues.

According to a first aspect of the invention there is provided a killswitch system for an operator-controlled powered apparatus having a location at which the presence of an operator is preferred, the system including a sensor for scanning a search area to detect the presence or absence of objects in the search area, and a controller in communication with said sensor, wherein the controller is programmed to generate a killswitch signal in response to a predetermined reading or signal from said sensor indicative of the absence of an operator within the search area, for automatically cutting off power for powered operation of the apparatus.

The use of a sensor for monitoring the normal position of the pilot at the controls of a powered boat overcomes the need for a conventional tether system, and the controller provides for automatic and tetherless activation of the killswitch circuit.

In preferred embodiments, the killswitch system utilises an ultrasonic detection system to scan the search area, as opposed to light or motion sensors, e.g. of the kind common in burglar alarm systems.

The system is preferably configured to run a calibration mode in order to define the predetermined reading from the sensor required to generate the killswitch signal. The calibration mode preferably involves multiple scanning operations intended to identify permanent objects within the search area (e.g. the steering or seat wheel of a vehicle), and so enable the presence of non-permanent objects (e.g. the driver or pilot of the vehicle) to be identified during normal use.

Preferably, the controller is programmed to operate a normal working mode in which sensor readings are compared against readings when from the calibration mode, in order to determine whether an operator is present in the search area during normal use.

The calibration mode preferably includes a calibration protocol wherein at least one scanning operation is conducted with an operator is present in the search area and at least one scanning operation is conducted without an operator present in the search area.

Another aspect of the invention provides a powered water craft including a control station at which the presence of a pilot is preferred to control operation of the water craft, the water craft further including a tetherless killswitch system configured to provide automatic power cut off for the water craft, the killswitch system having a sensor arranged to scan a search area for monitoring the presence of a pilot at the control station, the killswitch system further having a controller in communication with the sensor, wherein the controller is programmed to generate a killswitch signal in response to a signal or reading from said sensor indicative of the absence of a pilot in the search area, for automatically cutting off power for the powered movement of the water craft.

The killswitch system preferably includes a calibration routine for identifying permanent and non-permanent objects within the search area, to prevent incorrect generation of the killswitch signal. A further aspect of the invention provides an operator detection system for monitoring the presence of an operator at a preferred location, the system including a sensor for scanning a search area and a controller for communication with said sensor, wherein the controller is programmed to generate an alarm signal in response to a predetermined reading or signal from said sensor indicative of the absence of a non-permanent object within the search area, wherein the system includes a calibration mode for defining the predetermined reading or signal from the sensor required to generate the alarm signal, the calibration mode including multiple scanning operations in order to recognise the presence of permanent objects within the search area and so enable the presence of non-permanent objects to be identified.

Another aspect of the invention provides a killswitch system for a powered apparatus having a location at which the presence of an operator is preferred, the system including a sensor for scanning a search area and a controller for communication with said sensor, wherein the controller is programmed to generate an alarm signal in response to a predetermined reading or signal from said sensor indicative of the absence of a nonpermanent object within the search area, wherein the system includes a calibration mode for defining the predetermined reading or signal from the sensor required to generate the alarm signal, the calibration mode including multiple scanning operations in order to recognise the presence of permanent objects within the search area and so enable the presence of non-permanent objects to be identified.

There is also provided a powered watercraft including the killswitch system according to the above aspect of the invention. A still further aspect of the invention provides a calibration mode for a detection system having a sensor for monitoring a search area to determine the presence of a non-permanent object in the search area, the calibration mode including multiple scanning operations using said sensor in order to recognise the presence of permanent objects within the search area and so enable the presence of non-permanent objects to be identified. A yet further aspect of the invention provides a detection system having a sensor for monitoring a search area to determine the presence of a non-permanent object in the search area, the detection system including a calibration mode which involves multiple scanning operations using said sensor in order to recognise the presence of permanent objects within the search area and so enable the presence of non-permanent objects to be identified.

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure lisa schematic perspective view of part of a powered boat;

Figure 2 is a schematic front view of a sensor unit for use as part of a killswitch system for a power boat;

Figure 3 is a schematic part cross-sectional view of the sensor unit of Figure 2;

Figure 4 is a schematic front view of a control panel for the powered boat of Figure 1 incorporating three sensor units;

Figure 5 is a block diagram illustrating the electronic components of the a preferred killswitch system for a powered boat;

Figure 6 is a graph illustrating an example of values which might be experienced during the ‘operator not present’ part of a calibration phase of the killswitch system; and

Figure 7 is similar to Figure 6 and illustrates an example of values which might be experienced during the ‘operator present’ part of a calibration phase of the killswitch system.

The cockpit or control station of a powered boat is indicated generally at 100 in Figure 1, including a human pilot or operator 102 on a seat 104 positioned behind a main control panel 106 having a steering wheel 108 by means of which the direction of the boat is intended to be controlled. In order to overcome the problems associated with conventional tether-type killswitch systems, sensors 110 are provided for monitoring the presence of the operator at the control station. The sensors 110 form part of a tetherless killswitch system, which includes an on board controller (not shown) configured to automatically cut off power to the boat’s engine if the sensors detect that the operator is not present at the control station.

Figures 2 and 3 show an ultrasonic sensor unit 112 for use in the system of Figure 1. The unit 112 includes an ultrasonic transmitter 114 and an ultrasonic receiver 116. The transmitter 114 and receiver 116 are located in separate housings, mounted one on top of the other. In this embodiment, a piezoceramic element 118, 120 is mounted in the front face 122 of each housing, via an annular bush 124, to act as a transmitter or receiver of ultrasonic vibration. A single power and return cable 126 is connected to the unit 112. Internally, the cable 126 provides a signal from an external controller (not shown), e g. the on board controller, to a trigger or driver circuit 128 in the transmitter 114, for ultrasonic activation of the piezoceramic element 118. An amplifier circuit 130 is connected to the piezoceramic element 120 in the receiver 116, for enhancing ultrasonic vibrations detected by the piezoceramic element 120 in use, and for providing a return signal to the external controller, via the cable 126.

Although a single piezoceramic element can be used as a transmitter and receiver, the use of a receiver ceramic which is separate from the transmitter ceramic has been found to be advantageous, e.g. in reducing the reception of ultrasonic vibration passed internally to the piezoceramic receiver through the housing.

Figure 4 shows a control panel for the control station of a power boat, the control panel incorporating three sensor units 112 of the kind shown in Figures 2 and 3. The transmitter ceramics are directed to define a search area intended to cover the preferred operative position of an operator, e.g. the region around and including the pilot’s seat.

The sensor units 112 are in communication with the on board controller (not shown), which can be used to trigger the transmitter ceramics 118. The receiver ceramics 120 will then pick up reflected ultrasonic vibrations. A single sensor unit 112 may be preferred in certain applications.

Figure 5 is intended to summarise the electronics associated with the killswitch system of Figure 4. The sensor units 112 communicate with a controller 130 having a killswitch output 132 to the boat’s engine 134. In particular, the sensor units 112 provide signals to the controller 130 indicative of the presence of objects within the search area. A change in the return time of ultrasonic vibrations from the transmitter ceramics 118 to the receiver ceramics 120 will produce a change in the signal to the controller 130, and such changes are indicative of a change in the presence or absence of an object within the search area.

The controller 130 is programmed with a calibration mode, in order to identify static objects within the search area, such as the seat 104 or steering wheel 108, and so prevent incorrect activation of the killswitch output 132.

In general terms, the calibration mode includes a protocol which takes two sets of control readings - one set of readings from the or each sensor unit when the operator is present in the search area, and another set of readings when the operator is not present. These control readings are stored for use during the normal working mode of the system.

For example, a value which appears on both sets of control readings is indicative of permanent objects within the search area - these can be disregarded when determining the presence or otherwise of the operator during the normal working mode of the system. A value which only appears when the operator is not present is indicative of another person or object behind the preferred working position of the operator, and so can also be disregarded. A value which only appears when the operator is present in the search are is indicative of the operator.

The controller is programmed to compare the return signals from the sensor units during the normal working mode against the stored control readings from the calibration mode, in order to determine whether or not the operator is present in the search area.

Figures 6 and 7 show examples of the outputs which might be obtained during the calibration mode, when the operator is absent and when the operator is present. Figure 6 shows the results from a scanning operation with the operator not present, wherein an ultrasonic transmission 140 from the sensor unit results in the reception of reflected ultrasonic vibrations from a permanent object in front of the intended position of the operator, e.g. the steering wheel 108. Figure 7 shows the results from a scanning operation when the operator is present, wherein the ultrasonic transmission 140 from the sensor unit results in the reception of reflected ultrasonic vibrations from a permanent object in front of the intended position of the operator, e.g. the steering wheel 108, as well as a further object (i.e. the operator 102).

The calibration mode is used to create a virtual map of the reflective responses to the triggered outputs from the sensor units. Mapping the search area with and without a person there shows what the expected responses should be when there operator is absent. The system remembers objects, such as the steering wheel, which should be in view whether or not the pilot is present, against objects such as the seat back which will not be seen when the pilot is present.

The calibration mode enables the killswitch system to be transferable to other vessels. Indeed, the calibration mode and sensors can be used in other applications which require the presence of an operator at a given location, such as for monitoring the presence of a driver in a vehicle or the presence of an operator at a piece of machinery or industrial plant. As such, the sensors and calibration mode define an operator detection system which may be separable from the overall killswitch system.

In preferred embodiments, the calibration protocol takes the control readings from each sensor unit in turn. Multiple readings from each sensor unit are preferably taken at both of the control stages (operator present/operator not present), e.g. between 3 and 8 readings. This enables an average set of values to be stored for each stage (wherein undue noise can be filtered from the recorded values), for comparison during the normal working phase of the controller.

The calibration protocol preferably includes an initial test loop to check that the sensors are all active.

In normal use, the controller 130 is programmed to activate the trigger circuits simultaneously, e.g. multiple times per second, so as to take a generally continuous set of readings from the search area. If the controller 130, upon comparison of the normal working readings with the control readings, determines that the operator is not present for more than a predetermined time period, e.g. 1-2 seconds, the controller is programmed to activate the killswitch output, to cut power to the engine 134 and so immobilise the vessel. Again, multiple readings may be used to create an average reading for comparison with the control readings.

The controller may be programmed to disregard normal working readings indicative of distant objects, e.g. vibrations received after a predetermined time period, in order to minimise the amount of data under comparison.

The controller may be programmed to analyse the relative difference between the control readings and the normal working readings. If a normal working reading falls between the ‘present’ and ‘absent’ parameters defined by the control readings, the controller may designate the reading as a ‘maybe’ output from the sensor (instead of an ‘present’ or ‘absent’ output), to prevent a false trigger. The detection of multiple ‘maybe’ signals may be indicative of a problem with the system/sensor unit. The controller may be programmed to trigger the killswitch signal upon detection of a predetermined number of consecutive ‘maybe’ output.

Claims

1. A killswitch system for an operator-controlled powered apparatus having a location at which the presence of an operator is preferred, the system including an ultrasonic sensor unit configured to emit and receive ultrasonic vibrations as part of a scanning operation, for scanning a search area to detect the presence or absence of objects in the search area, and a controller in communication with said sensor, wherein the controller is programmed to generate a killswitch signal in response to a predetermined reading or signal from said sensor indicative of the absence of an operator within the search area, for automatically cutting off power for powered operation of the apparatus, wherein the ultrasonic sensor unit includes an piezoelectric transmitter and piezoelectric receiver separate from the piezoelectric transmitter, wherein the sensor unit includes a trigger or driver circuit for ultrasonic activation of the transmitter in response to a trigger signal from the controller, and an amplifier circuit for enhancing ultrasonic readings detected by the receiver to provide a return signal to the controller.

2. A killswitch system according to claim 1 wherein the sensor forms part of an ultrasonic detection system for scanning the search area.

3. A killswitch system according to claim 1 wherein the system is configured to run a calibration mode in order to define the predetermined reading or signal from the sensor required to generate the killswitch signal.

4. A killswitch system according to claim 3 wherein the calibration mode involves multiple scanning operations to identify permanent and non-permanent objects within the search area.

5. A killswitch system according to claim 3 wherein the controller is programmed to compare normal working readings or signals from the sensor against readings or signals from the calibration mode, in order to determine whether an operator is present in the search area during normal use.

6. A killswitch system according to claim 3 wherein the calibration mode includes a calibration protocol which requires at least one scanning operation to be conducted with an operator present in the search area and at least one scanning operation to be conducted without an operator present in the search area.

7. A killswitch system according to claim 1 comprising an ultrasonic sensor unit configured to emit and receive ultrasonic vibrations as part of a scanning operation.

8. A powered watercraft including the killswitch system of any of claims 1 to 7.