GB2396905A

GB2396905A - A device for generating a control signal

Info

Publication number: GB2396905A
Application number: GB0230340A
Authority: GB
Inventors: Adrain Harwood
Original assignee: Armstrong Healthcare Ltd
Current assignee: Armstrong Healthcare Ltd
Priority date: 2002-12-31
Filing date: 2002-12-31
Publication date: 2004-07-07
Also published as: GB0230340D0

Abstract

A method and apparatus 1 for generating a control signal, preferably to control at least one function of a medical device such as an endoscope. The apparatus comprising: an attachment arrangement for attaching the apparatus to the head of a user; two or three accelerometers configured to sense movement of the apparatus about respective first, second and third axes and each having an output, the directions of the axes being offset with respect to one another; and a transmission arrangement 3 to transmit the control signal to a receiver 4 via a wireless link, the outputs from the accelerometers being connected to the transmission arrangement 3 via a processor 2. Also disclosed is an optional switch to disable the control of the medical device.

Description

"A device for generating a control signal" THIS INVENTION relates to a

device for generating a control signal, and in particular concerns a device for generating a signal to control the view provided by an endoscopic device, of the type employed in minimal access surgery.

There are circumstances in which it is desirable to exercise control over apparatus while leaving one's hands free to perform other tasks. One example of such circumstances is where a surgeon or team of surgeons is performing minimal access or "keyhole" surgery, an endoscopic device is typically used to provide the surgeon with an on-screen view of the internal region of the patient on which surgery is being performed. An endoscopic device generally consists of a small camera mounted on the tip of a probe, and the direction in which the camera points (with respect to the tip of the probe) is controllable to provide an appropriate view.

The direction in which the camera of an endoscopic device is pointed is typically controlled by a joystick or similar input means, and in general the control of the camera orientation must be performed by someone other than the surgeon, who will have both hands occupied in controlling a surgical instrument. This arrangement, however, increases the number of individuals that are required to perform an operation, and also incurs the risk that the person operating the camera will point the camera in a direction other than that desired by the surgeon, which may waste time or impair the effectiveness of the operation.

It is an object of the present invention to seek to alleviate one or more of the above difficulties.

Accordingly, one aspect of the present invention provides a device for generating a control signal, the device comprising: an attachment arrangement for attaching the device to the head of a user; first and second accelerometers configured to sense movement of the device about respective first and second axes and each having an output, the directions of the first and second axes being offset with respect to one another; and a transmission arrangement to transmit the control signal, the outputs from the first and second accelerometers being connected to the transmission arrangement.

Advantageously, the first and second axes are substantially orthogonal to one another.

Preferably, the device further comprises a third accelerometer operable to sense movement of the device about a third axis whose direction is offset with respect to that of both the first and the second axes.

Conveniently, the third axis is substantially orthogonal to that of both the first and the second axes.

Advantageously, at least one accelerometer is configured to sense translational motion of the device.

Preferably, the outputs from the first and second accelerometers are connected to the transmission arrangement via a processor.

Another aspect of the present invention provides a control system comprising: a device according to any preceding claim; a receiver operable to receive the control signal; and a controller connected to the receiver and operable to control at least one function of a medical device in response to the control signal.

Conveniently, the medical device is an endoscopic device.

Advantageously, the system further comprises a switch which, in a first position, allows the control of the medical device through movement of the device, and which, in a second position, does not allow the control of the medical device through movement of the device.

Preferably, the receiver receives the control signal from the transmission arrangement via a wireless link.

A further aspect of the present invention provides a method of generating a control signal, comprising the steps of: providing first and second accelerometers configured to sense movement about respective first and second axes and each having an output, the directions of the first and second axes being offset with respect to one another; attaching the first and second accelerometers to a user's head; providing a transmission arrangement to transmit the control signal; and connecting the outputs from the first and second accelerometers to the transmission arrangement.

Conveniently, the method further comprises the step of providing a third accelerometer configured to sense movement about a third axis, the direction of the third axis being offset with respect both to the first and the second axes.

Advantageously, the method further comprises the step of configuring one or more of the accelerometers to sense translational motion of the device.

Preferably, the method comprises the steps of: generating a control signal by the above method; receiving the control signal via a receiver; and controlling at least one function of a medical device in dependence upon the control signal.

Conveniently, the medical device is an endoscopic device.

In order that the present invention may be more readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying Figure, which shows a schematic representation of the components of a system embodying the present invention.

Referring to the Figure, the present invention comprises a control signal generation device 1, which is adapted to be attached to the head of a user.

Typically, this user will be a surgeon who is performing minimal access surgery. The control signal generation device 1 may be provided as part of a hat or head band, or may alternatively be stuck to the head of the user by a suitable adhesive. A skilled person will understand that there are many ways in which this may be achieved.

The control signal generation device 1 comprises a sensor arrangement comprising two or more accelerometers. The accelerometers are arranged so that, when the control signal generation device 1 is correctly attached the user's head, the accelerometers sense movement of the device 1 arising from movements of the user's head in at least one predetermined direction. For instance, one or more of the accelerometers may be arranged to sense movement of the device 1 arising from movements of the user's head in the "yaw" axis thereof, corresponding to a turn of the user's head to the left or to the right. Alternatively, or in addition, one or more of the accelerometers may be configured to measure movement of the device 1 arising from movements of the user's head in the "roll" axis, corresponding to a movement of the user's head in which the user's face remains facing forward but the user brings one ear closer to the corresponding shoulder.

Also, in combination with either or both of the above-described arrangements of accelerometers, the sensor arrangement may be configured to sense movement of the device 1 arising from movements of the user's head in the "pitch" axis, corresponding to a nodding motion of the head.

A skilled person will appreciate that there are several types of accelerometer that may be used to sense the above-mentioned motions of the user's head. For instance, some or all of the accelerometers could comprise "deflecting beam" accelerometers, which are provided with a beam of a known weight, which is supported at a proximal end thereof, the deflection of the distal end of the beam being measured to provide an indication of the acceleration of the accelerometer in a direction perpendicular to the longitudinal axis of the beam.

Such an accelerometer may be constructed by removing a substantially Ushaped portion from a printed circuit board (PCB) to leave a "tongue" of material. A strain gauge (for instance comprising piezoelectric material) is provided to measure the deflection of the tongue, which will vary in dependence upon the acceleration of the PCB in a direction perpendicular to the plane thereof.

Any other suitable type of accelerometer may also be employed with the present invention, and a skilled person will readily appreciate that there are several such types.

A processor 2 associated with the of the control signal generation device 1 receives the information relating to the sensed movement of the device 1, and passes this information to a transmitter 3, which is preferably also provided on the hat or head band to which the control signal generation device 1 is attached.

The processor 2 converts the raw data output by the sensor arrangement into a suitable form for transmission. In preferred embodiments of the invention, the transmitter 3 transmits the information in the form of an infrared signal, on a pulse code modulated carrier. However, it will be appreciated that there are many ways in which this information may be transmitted, and any suitable method, whether wireless or otherwise, may be used with the present invention.

The information transmitted by the transmitter 3 may (for instance, in the case of a "deflecting beam" accelerometer), relate to the absolute deflection of the beam due to gravity, by comparing the deflection of the beam with that of an initial reference position, which may be predetermined or calibrated at start- up. Alternatively, the information may comprise differences in the deflection of the beam over time.

The information transmitted by the transmitter 3 is received by a receiver 4, which passes the received signals to a decoder 5 (which may comprise a further processor), which in turn removes the carrier signal and reconstructs the sensed data that was output from the sensor arrangement.

The sensed data is then used to control at least one function of a medical device 6. It is envisaged that the present invention will find particular application in control of endoscopic devices, as discussed above. Preferably, movements of the user's head in a particular plane are used to control movement of the camera of an endoscopic device in corresponding planes. For instance, a movement of the head in the "yaw" axis, as discussed above, may control movement of the camera from left to right, and it is found that this is a simple and intuitive way of controlling the camera.

lO Alternatively, movement of the user's head in the "roll" axis may be used to control left to right movements of the camera. The user may be able to determine, via a suitable input means, which head movements correspond to certain movements of the camera of the endoscopic device.

Similarly, movements of the head in the 'pitch" axis may cause the camera to look up or down. The system may be configured so that only one axis of movement is sensed at any one time, or may be set up so that, by more complex movements of the head, the user can completely control the movement of the camera of the endoscopic device. The system may also be set up so that movements of the user's head control the magnification or zoom applied to the image gathered from the camera, and a skilled person will readily appreciate how this may be achieved.

In preferred embodiments of the present invention, a switch is provided which toggles the system between a controlling mode and a non-controlling mode. In other words, in one position of the switch, the user may move his or her head without affecting the operation of the endoscopic device, and in the other position of the switch the control system is "on", and movements of the user's head have an effect upon the operation of the endoscopic device. This switch may be conveniently provided as a foot switch, thereby allowing the user complete control over the movement of the camera of the endoscopic device while having both hands free.

It is to be understood that the control signal output by the control signal generation device 1 may comprise the raw data output by the accelerometers, may comprise set of instructions, output by the processor 2, which are suitable for use in directly controlling the medical device 6, or indeed may comprise the raw data with any intermediate level of processing applied thereto.

It is envisaged that surgeons may be reluctant to use the present invention for controlling invasive tools, for safety reasons that will be apparent.

However, it is considered possible that suitable safety procedures could be put into operation to allow the control of an invasive tool using the present 1 5 invention.

It will be understood that the present invention provides a powerful and intuitive method of controlling medical devices, which leaves a surgeon's hands free to perform other tasks.

In the present specification "comprises" means "includes or consists of" and "comprising" means "including or consisting of".

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS: 1. A device for generating a control signal, the device

comprising: an attachment arrangement for attaching the device to the head of a user; first and second accelerometers configured to sense movement of the device about respective first and second axes and each having an output, the directions of the first and second axes being offset with respect to one another; and a transmission arrangement to transmit the control signal, lO the outputs from the first and second accelerometers being connected to the transmission arrangement.
2. A device according to Claim l, wherein the first and second axes are substantially orthogonal to one another.
3. A device according to any preceding claim, further comprising a third accelerometer operable to sense movement of the device about a third axis whose direction is offset with respect to that of both the first and the second axes.
4. A device according to Claim 3, wherein the third axis is substantially orthogonal to that of both the first and the second axes.
5. A device according to any preceding claim, wherein at least one accelerometer is configured to sense translational motion of the device.
6. A device according to any preceding claim, wherein the outputs from the first and second accelerometers are connected to the transmission arrangement via a processor.
7. A control system comprising: a device according to any preceding claim; a receiver operable to receive the control signal; and a controller connected to the receiver and operable to control at least one function of a medical device in response to the control signal.
8. A system according to Claim 7, wherein the medical device is an endoscopic device.
9. A system according to Claim 7 or 8, further comprising a switch which, in a first position, allows the control of the medical device through movement of the device, and which, in a second position, does not allow the control of the medical device through movement of the device.
10. A system according to any one of Claims 7 to 9, wherein the receiver receives the control signal from the transmission arrangement via a wireless link.
11. A method of generating a control signal, comprising the steps of: providing first and second accelerometers configured to sense movement about respective first and second axes and each having an output, the directions of the first and second axes being offset with respect to one another; attaching the first and second accelerometers to a user's head; providing a transmission arrangement to transmit the control signal; and connecting the outputs from the first and second accelerometers to the transmission arrangement.
12. A method according to Claim 11, further comprising the step of providing a third accelerometer configured to sense movement about a third axis, the direction of the third axis being offset with respect both to the first and the second axes.
13. A method according to Claim 11 or 12, further comprising the step of configuring one or more of the accelerometers to sense translational motion of the device.
14. A method of controlling a medical device, comprising the steps of: generating a control signal by the method of any one of Claims 11 to 13; receiving the control signal via a receiver; and controlling at least one function of a medical device in dependence upon the control signal.
15. A method according to Claim 14, wherein the medical device is an endoscopic device.
16. A device substantially as hereinbefore described, with reference to the accompanying Figure.
17. A method substantially as hereinbefore described, with reference to the accompanying Figure.
18. Any novel feature or combination of features disclosed herein.