GB2610631A

GB2610631A - Seat monitoring apparatus

Info

Publication number: GB2610631A
Application number: GB2113024.0A
Authority: GB
Inventors: Bantounos Kostantinos; Underwood Ian; Marland Jamie
Original assignee: Duchenne Uk
Current assignee: Duchenne Uk
Priority date: 2021-09-13
Filing date: 2021-09-13
Publication date: 2023-03-15
Also published as: WO2023037115A1; GB202113024D0

Abstract

The seat monitoring apparatus has a temperature sensor 310, a humidity sensor 310, and a pressure sensor 320 for measuring properties associated with a user sitting on a surface. The apparatus has a control unit configured to determine, based on measurements from the sensors 310, 320, whether a discomfort condition is satisfied. If satisfied, the control unit is configured to trigger a pre-emptive action. The pre-emptive action may be: an alert e.g. from a speaker, or a notification on a mobile device; modification of a profile of the surface to change a user’s posture, e.g. by varying an inflation level; or triggering of a heating 340 or cooling 350 element such as a fan. The discomfort condition may require the passing of a threshold by one or all sensors 310, 320, and may be set based on characteristics of the user. The apparatus may be included in a seat cushion of a wheelchair to prevent pressure sores.

Description

SEAT MONITORING APPARATUS

Background

The present invention is concerned with a seat monitoring apparatus particularly, but not exclusively, for detecting discomfort of a user.

When sitting still for extended periods of time, even positions that were initially comfortable can become uncomfortable. If remaining seated in such positions for too long under certain conditions, pressure sores can develop.

This is particularly the case in contexts where a user is prone to sitting for long periods of time and potentially without a natural opportunity to take a break from sitting or change his/her seated position. Thus, wheelchair users are particularly at risk of developing pressures sores due to maintaining their seated position in the wheelchair for extended periods of time. Similarly, long-distance lorry drivers, passengers/pilots in an airplane, or passengers on long train rides could be at risk of discomfort due to their seated position.

The inventors have developed an apparatus that can provide improved identification of the conditions under which a user is likely to develop a pressure sore or otherwise feel discomfort such that a pre-emptive action can be taken to avoid the onset of pressure sores/discomfort.

Summary of the Invention

Aspects of the invention are set out in the accompanying claims.

Viewed from a first aspect, there is provided a seat monitoring apparatus comprising: a plurality of sensors collectively arranged to measure, in use, properties associated with a user sitting on a surface, the plurality of sensors including a temperature sensor, a humidity sensor, and one or more pressure sensors; and a control unit communicatively coupled to the plurality of sensors and configured to determine, based on measurements from the plurality of sensors, whether a discomfort condition is satisfied; wherein in response to determining that the discomfort condition is satisfied, the control unit is configured to trigger a pre-emptive action.

The term 'discomfort condition' is intended to refer to a predetermined threshold or combination of thresholds for measured parameters which have been predetermined to cause either discomfort or a deteriorating condition for the seated individual.

The inventors recognised that the onset of pressure sores can be predicted by a combination of temperature, humidity, and pressure measurements taken from a surface (such as the surface of a seat) on which a user is sitting. The seat monitoring apparatus is therefore provided with sensors for measuring such quantities and to provide the data from those sensors to a control unit. The control unit may comprise processing circuitry such as a microprocessor or microcontroller and is arranged to perform control functionality for the seat monitoring apparatus. The control unit is coupled to the sensors to receive these measurements. The control unit makes use of a discomfort condition such that based on the combination of the temperature, humidity and pressure measurements, the control unit is able to determine whether the discomfort condition is satisfied. The discomfort condition may be set such that the condition is satisfied when a combination of the measurements from the sensors indicates that a user is at increased risk of developing a pressure sore or otherwise becoming uncomfortable.

If the discomfort condition is not satisfied, the control unit may continue monitoring the sensors and take no further action. However, if the discomfort condition is satisfied, which may be indicative that the user is at risk of developing a pressure sore/facing discomfort, the control unit triggers a pre-emptive action to avert the onset of pressure sores/discomfort. In this way, the seat monitoring apparatus can respond proactively to prevent the user developing a pressure sore or becoming uncomfortable in their seating position.

The seat monitoring apparatus itself could take a number of possible forms. In some examples however, the seat monitoring apparatus is configured to be placed into a seat cushion where the surface on which the user is sitting is the seat cushion itself By placing the seat monitoring apparatus into a standalone cushion, the cushion may be placed on any object on which the user sits (e.g., a chair, a bench or a bed) such that a dedicated seat for performing the monitoring need not be provided. Alternatively, in some examples, the seat cushion is a seat cushion of a particular seat intended to be used with the seat monitoring apparatus. For example, the seat cushion may be a seat cushion of a wheelchair, on the basis that users typically remain seated in their wheelchair for extended periods of time.

Other examples of seats with which the seat monitoring apparatus may be used include airplane seats, seats for cars, lorry seat, coach seats, and train seats. For each of these, a user may remain seated in the seat for a long period and it may be an object of the provider of the seat (e.g., airline carrier) to provide a comfortable experience for the user.

In some examples, the seat monitoring apparatus may be retrofitted into existing seats, for example, where the seat cushion of the seat can be opened to allow insertion of the seat monitoring apparatus. In this way, even seats not originally intended to support monitoring of the properties associated with the onset of pressure sores as described can be used with the seat monitoring apparatus.

The control unit may determine that the discomfort condition is satisfied in a number of possible ways. In some examples, the discomfort condition is dependent on each of the temperature, humidity and pressure measurements from the respective sensors satisfying a respective threshold. It will be appreciated that, as used herein, satisfying a threshold may relate to a quantity meeting/exceeding a threshold or meeting/falling below threshold. Thus, in this case, the discomfort condition may be satisfied based on the temperature measured by the temperature sensor being too high or too low. However, in this example, for the discomfort condition to be satisfied, all of the measurements need to satisfy their respective thresholds. This discomfort condition may be used based on an understanding that pressure sores arise due to a combination of factors and so when a certain temperature and humidity are reached as well as the pressure in a particular location exceeding a certain value, the likelihood of developing a pressure sore is significantly increased relative to a risk when only a subset of these thresholds are satisfied. Thus, the discomfort condition may be a pressure sore condition tailored such that the condition is satisfied when the measurements from the sensors indicate a heightened risk of the user developing a pressure sore.

Alternatively, or additionally, the control unit may be configured to determine that the discomfort condition is satisfied when the measurements from any of the sensors satisfy a threshold for that sensor and measurement. For example, if the temperature exceeds a certain value, the control unit may determine that the discomfort condition is satisfied, regardless of the measurements of humidity and pressure. This may be the case where it is recognised that any one of pressure, temperature, and humidity can individually cause discomfort comfort, even in the absence of the other factors.

In some examples, the discomfort condition is preset based on measurements from the sensors deemed applicable to all users. However, in some examples, the discomfort condition is set for the particular user based on the personal characteristics such as their weight, expected usage of the seat (e.g., amount of time spent in a wheelchair per day) and/or their propensity for developing pressure sores or otherwise feeling discomfort when sitting. This allows a more accurate determination to be made as to when the user is at risk of developing pressure sores and so when a pre-emptive action should be taken. To support the setting of a discomfort condition for a particular user, the control unit may be configured to receive input indicative of a new discomfort condition and in response to the new discomfort condition, to begin using that new discomfort condition. The new discomfort condition could be received via a user device (e.g., a mobile phone) or input to the seat monitoring apparatus via a control panel of a wheelchair in which the seat monitoring apparatus is installed, for example.

Turning now to the pre-emptive action triggered by the control unit in response to determining that the discomfort condition is satisfied, this pre-emptive action may involve issuing an alert to the user to let the user know that the discomfort condition has been satisfied. The user may then modify their sitting position themself or otherwise address the cause of the discomfort so as to avoid further discomfort or developing pressure sores. The alert may take the form of a notification at a mobile device of the user where the control unit is in communication with such a mobile device. Additionally, or alternatively the seat monitoring apparatus may comprise an output element by which the alert can be issued to the user. Thus, the need for a connected mobile device in order to issue the alert can be avoided. Further, the output element may be more suited for attracting the user's attention and/or may more intuitively indicate an issue with the seat. For example, the output element may be a speaker or a hapfic feedback element (or both may be provided) to issue an audible alert or a vibration through the surface respectively. By bringing the attention of the user to the possible discomfort/the heightened risk of developing pressure sores, the user may themself address the issue by changing their seated position, moving out of the seat or moving to a cooler/warmer location, for example.

However, in some examples, as well as or instead of issuing the alert, the control unit is configured to trigger, as the pre-emptive action, a remedial action to address the cause of the discomfort condition being satisfied. It will be appreciated that the particular form of the remedial action taken may depend on the cause of the discomfort condition being satisfied.

That is, the remedial action may be selected based on the measurements from the sensors.

In some examples, the remedial action is taken to modify the posture of the user. The seat monitoring apparatus may comprise one or more actuating elements that can be controlled by the control unit and that may be used to modify a surface profile of the surface on which the user is sitting. In some examples, the actuating elements are air cells positioned with the seat monitoring apparatus in a seat cushion such that the control unit can selectively inflate and deflate the air cells to modify the profile of the surface on which the user is sitting. By modifying the surface profile in this way, the user's posture may be automatically altered, which itself may address the cause of the discomfort condition being satisfied. For example, by distributing the user's weight across the surface, the pressure measured by a particular pressure sensor may be reduced. The modification of the surface profile may be random or may cycle through a series of profiles. In some examples, the seat monitoring apparatus comprises a plurality of pressure sensors and a user's initial posture is characterised based on the relative pressures detected at the pressure sensors. For example, if the pressure sensors at the front of the surface detect a higher pressure than near the back of the surface, the control unit may determine that the user is leaning forwards. Based on the detected posture, the control unit be configured to determine a new posture for the user and to selectively adjust the surface profile using the actuating elements so that the user adopts this posture. In the example where the user is leaning forwards, this may therefore involve inflating air cells forming the actuating elements at the front of the chair and deflating the air cells towards the back of the chair so as to readjust the user's weight backwards. By adjusting where the user's weight is positioned in this way, the seat monitoring apparatus may avoid the user placing too much weight in one location for a long period, and consequently reduce the likelihood of pressure sores occurring or the user experiencing discomfort.

Other remedial actions that may be triggered by the control unit include operating a heating element provided as part of the seat monitoring apparatus. Thus, if the control unit determines that the temperature measurements from the temperature sensor fall below a threshold level, the control unit may automatically trigger the heating element to heat the surface to avoid the user becoming too cold.

Similarly, if the control unit determines based on the measurements from the temperature sensor that the user is too hot or based on the measurements from the humidity sensor that the humidity is too high, the control unit may trigger a cooling element of the seat monitoring apparatus to cool the surface. The cooling element may be a fan, provided for example within the seat cushion of a wheelchair and operable by the control unit when it is determined that the user is too hot or the humidity is too high.

By triggering such remedial actions, the seat monitoring apparatus may act to automatically address discomfort detected by the control unit.

Further, in some examples, the control unit is configured to store the measurements from the plurality of sensors. The control unit may selectively store the measurements when the discomfort condition is satisfied, or may store the measurements at regular intervals, or indeed store all measurements received from the sensors. These measurements may be provided to a separate device via a communication element (e.g., via a BluetoothTM communication element of the seat monitoring apparatus). The transferred measurements may then be used by a doctor or other healthcare professional to assess the user's likelihood of developing pressure sores, the conditions under which the user is sitting and/or to determine how the discomfort condition should be set to accurately predict when the user is likely to feel discomfort/develop a pressure sore.

As well as or instead of alerting the user to the discomfort condition being satisfied, the pre-emptive action may involve alerting another person (e.g., a doctor, family member, or carer). This may for example be done in addition to taking a remedial action to adjust the user's posture automatically and/or could be performed in response to the seat monitoring apparatus needing to take a pre-emptive action a certain number of times in a fixed period. In this way, the other person (such as a carer, doctor, or family member) may be able to investigate the cause of the discomfort condition being satisfied and why the user and/or seat monitoring apparatus were not able to suitably the situation by themselves. Hence, an automatic escalation can be effected by the seat monitoring apparatus in such cases.

The seat monitoring apparatus may also be configured to predict a remaining amount of time until the discomfort condition is likely to be satisfied. Based on this prediction, the seat monitoring may be able to warn or indicate to the user an amount of time left sitting in their current position before a new position should be adopted. The amount of time sitting in particular position may vary significantly for different user. For example, a heavier user is likely to become uncomfortable in a particular position more quickly than a lighter user. As such, the seat monitoring apparatus may be configured such that a user can personalise the prediction time based on their own personal experience so as to provide a more accurate prediction for that user.

Thus there has been described an apparatus for detecting conditions under which a user might be likely to develop a pressure sore and/or experience discomfort. When such conditions are detected, the apparatus can take a pre-emptive action to warn the user and/or address the situation in order to prevent the further comfort or the onset of pressure sores.

Viewed from another aspect of an invention described herein, there is provided a method of monitoring the comfort of a user sitting on a surface, the method comprising: measuring, using a plurality of sensors, properties associated with a user sitting on a surface, wherein the plurality of sensors include a temperature sensor, a humidity sensor, and one or more pressure sensors; determining, based on measurements from the plurality of sensors, whether a discomfort condition is satisfied; and in response to determining that the discomfort condition is satisfied, triggering a pre-emptive action.

Viewed from yet another aspect, there is provided a wheelchair comprising the seat monitoring apparatus described above.

Viewed from yet another aspect, there is provided a seat cushion for monitoring the comfort of a user, the seat cushion comprising: a plurality of sensors collectively arranged to measure, in use, properties associated with a user sitting on a surface, the plurality of sensors including a temperature sensor, a humidity sensor, and one or more pressure sensors; and a control unit communicatively coupled to the plurality of sensors and configured to determine, based on measurements from the plurality of sensors, whether a discomfort condition is satisfied; wherein in response to determining that the discomfort condition is satisfied, the control unit is configured to trigger a pre-emptive action.

Figures Aspects of the invention will now be described, by way of example only, with reference to the accompanying figures in which: Figure 1 shows a wheelchair of the type with which one example of the invention may be used; Figure 2A shows a schematic of selected components of the wheelchair of Figure 1; Figure 2B shows a schematic of selected components of a user device that may be used with the wheelchair of Figure 1; Figure 3 shows a schematic of a seat monitoring apparatus according to one

example;

Figure 4 shows a seat with which the seat monitoring apparatus of Figure 3 may be used, part of the seat cut-away to show the seat monitoring apparatus; Figure 5 is a diagram illustrating conditions under which the discomfort condition is satisfied according to one example; and Figure 6 is a flowchart illustrating a method of monitoring a seat on which a user is sitting according to one example.

Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field. As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to". The invention is further described with reference to the following examples. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples. It will also be recognised that the invention covers not only individual embodiments but also combination of the embodiments described herein.

The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the spirit and scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc, other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.

In the present application, the words "configured to..." are used to mean that an element of an apparatus has a configuration able to carry out the defined operation. In this context, a "configuration" means an arrangement or manner of interconnection of hardware or software. For example, the apparatus may have dedicated hardware which provides the defined operation, or a processor or other processing device may be programmed to perform the function. "Configured to" does not imply that the apparatus element needs to be changed in any way in order to provide the defined operation.

Detailed Description

Figure 1 shows a wheelchair 2 of the type with which one example of the invention may be used. In this example, the wheelchair 2 is a motorised wheelchair driven by a motor housed within the base 10 that is arranged to drive the wheelchair 2 based on inputs from a user at a gesture controller 40 and/or a secondary controller 70. However, it will be appreciated that the present techniques are also applicable in other forms of wheelchairs such as manual wheelchairs which are driven by a user turning the wheels directly or by another person pushing the wheelchair. As shown in Figure 1, the wheelchair 2 has two front wheels 22 which are driven by the motor and can be operated independently by a control unit such that the wheelchair 2 is able to drive in a straight direction, turn left or right and drive at different speeds. To support the ability of the wheelchair 2 to make a turn in a small amount of space, the wheelchair 2 has rear omni-wheels 24. The omni-wheels 24 are able to rotate about an axle running through the centre of the wheel (as is the case for a normal wheel) to enable motion in a forward/backward direction, and also comprise rollers mounted around the circumference of the wheel to enable smooth motion of the wheel in a direction parallel to the axle. This allows the wheelchair 2 to turn with a small turning circle which may be desirable when operating the wheelchair 2 in cramped environments.

Mounted on top of the base 10 is a seat 30 having a seat base 32 on which a user can sit and a seat back 34 to support the user's back when sitting. The seat base 32 and seat back 34 may be fixedly mounted to one another or may be pivotally mounted such that the angle formed between the seat base 32 and the seat back 34 can be altered to provide a comfortable sitting position for the user. For further support when sitting, the seat 30 comprises a headrest 36 to support the user's head when sitting in the wheelchair.

The seat 30 also has armrests 38 on which the user can rest his or her arms and footrests 28 extending from the seat base 32. The footrests 28, armrests 38 and headrest 36 are adjustable so that the position and angle of these components relative to the seat base 32 and seat back 34 can be altered and/or these components removed entirely.

Located at the end of one of the armrests 38 is a gesture controller 40. The gesture controller 40 allows the user to control the motion of the wheelchair 2. As shown in Figure 1, the gesture controller 40 is seated in a mandrel which enables the use of the gesture controller 40 as a joystick whereby pivoting of the gesture controller 40 in the mandrel is used to indicate a direction and speed in which the wheelchair 2 is to travel. The gesture controller 40 may also be removed from the mandrel whereupon control of the wheelchair 2 can be performed by moving the gesture controller 40 freely in three-dimensional space unconstrained by the attachment to the mandrel. This may provide a more comfortable and intuitive method of controlling the wheelchair 2, particularly where the user has limited range of motion or level of motor control, for example.

To display the detected input from the gesture controller 40 and any other information that may be useful for the user, a display 60 is provided at the end of one of the armrests 38.

The display 60 is mounted at an angle relative to the armrest such that the display 60 is oriented for easy viewing by a user sitting in the seat 30. The detected input from the gesture controller 40 (e.g., a direction and speed in which the wheelchair 2 is to travel based on the manipulation of the gesture controller 40) is displayed on the display 60. The display 60 may also display other information such as a battery level for the wheelchair 2, navigation information and/or notifications from a connected user device (e.g. mobile phone).

Situated at the end of the other arm rest 38 is a phone holder 70. The phone holder is arranged to securely hold the user's phone. Further, the phone holder 70 is pivotally mounted such that angle of the phone can be adjusted. This allows the user to position that mobile phone at an angle that allows for comfortable viewing.

In some examples, a secondary controller (not pictured) is also provided. This controller may be used to control functions of the wheelchair other than the movement as controlled by the gesture controller 40. For example, the seat 30 may be mounted such that the seat 30 can be elevated vertically from the base 10 by means of an extendable riser post. This would allow the user to adjust the seat height so as to position themselves at the eye line of a person with whom they were talking or to have a better view (e.g., over a counter in a shop). The secondary controller 70 may therefore be used to control the vertical motion of the seat 30. Similarly, the secondary controller 70 may be used to adjust the positioning of the armrests 38, footrests 28 and/or the headrest 36. In the example of Figure 1, such a secondary controller is not provided and this functionality is controlled via display 60.

As is also illustrated in Figure 1, a depth camera 50 is situated in the base 10 of the wheelchair 2. The depth camera 50 is configured to capture images as well as position information for the objects in those images. These can then be used to aid in navigation, detection of obstacles and the identification of obstacles that may be impassable to wheelchair 2 (e.g., kerbs above a height scalable by the wheelchair 2). Based on detection of such impassable obstacles, a pre-emptive action to warn the user and/or prevent the user from attempting to drive over the obstacle may be issued.

Figures 2A and 2B show schematics of selected components of the wheelchair 2 and of a user device that may be used with the wheelchair 2. It will be appreciated that not all features of the wheelchair 2 and the user device are included in these schematics and that these figures are used to explain certain features and their interactions in accordance with an illustrative example. Other examples may contain more or fewer components and the relationship between the components may differ from that shown in Figures 2A and 2B.

As shown in Figure 2A, the wheelchair 2 comprises a central control unit 200 that coordinates the function of the wheelchair 2. The control unit 200 operates in conjunction with a driving control unit 210 that handles the control of the wheelchair's motion and calculates and issues control signals (e.g., to one or more motors) to cause the wheelchair 2 to move. The wheelchair 2 also has a seat control unit 230 that performs seat monitoring in order to maintain user comfort and/or reduce the risk of the user developing pressure sores by virtue of their position on the seat for an extended period of time. There is further an obstacle detection control unit 250 coupled to the control unit 200 which makes use of a depth camera 50 to identify obstacles and determine whether the obstacles are passable to the wheelchair 2. The control unit 200 is also coupled to a gesture controller control unit 260 which interprets the inputs from the gesture controller 40 to produce control signals that can be used to control the wheelchair 2.

The control unit 200 provides an interface by which the control units 210, 230, 250, 260 as well as the other components of the wheelchair 2 can interact. For example, as the gesture controller control unit 260 interprets the gestures and determines control signals for driving the wheelchair, the control unit 200 can pass these control signals to the driving control unit 210 whereupon the driving control unit 210 can control the wheelchair 2 to move in accordance with the gestures performed by the user. Similarly, if the obstacle detection control unit 250 detects an obstacle that is deemed to be impassable to the wheelchair 2 (e.g., a kerb that is too high for the wheelchair 2 to mount), the control unit 200 may receive this information and control the driving control unit 210 to stop the wheelchair 2. It will be appreciated that Figure 2A illustrates one possible arrangement of control logic within the wheelchair and that other arrangements could be used, for example, providing a single control unit to handle all the control functionality of the wheelchair.

The seat control unit is coupled to a plurality of seat sensors including a temperature sensor 232, at least one pressure sensor 234 and a humidity sensor 236. The humidity sensor may be a relative humidity sensor to measure the relative humidity of the sensor's surroundings. As discussed in more detail below, the seat control unit 230 is responsive to measurements from these sensors to determine whether a discomfort condition is satisfied.

The discomfort condition is set so as to be indicative of a set of temperature, pressure and humidity values at which the user is likely to be at risk of developing a pressure sore. Additionally, or alternatively, the discomfort condition may be set such that the condition is satisfied when a user is expected to being feeling discomfort and so by anticipating this discomfort (or equivalently the onset of pressure sores), the seat control unit 230 can take a pre-emptive action to prevent discomfort/pressure sores.

As shown in Figure 2A, the seat control unit 230 is connected to a fan 238, a heater 240, and an actuator 242 which is able to control a surface profile of the seat. Making use of these components, the seat control unit 230 is able to respond pre-emptively when the discomfort condition is satisfied to adjust the temperature at the seat surface (using the fan 238 or heater 240 as appropriate) or to adjust the user's sitting position using actuator 242. It will be appreciated that the seat monitoring apparatus may be provided with more, fewer, or different components, e.g., in some examples the seat comprises actuator 242 but does not have the fan 238 or heater 240.

As another example of a pre-emptive action that may be taken and which may also be taken in response to detection of an impassable obstacle by the obstacle detection control unit 250, the wheelchair 2 may issue an audible alert via speaker 278 or issue hapfic feedback via haptic feedback element 276 which may be located for example, in the arm rest 38, gesture controller 40, or the seat base 32. The wheelchair 2 further comprises a communication element 274 with which the control unit 200 can communicate a user device.

For example, the communication element 274 may be a BluetoothTM communication element with the wheelchair 2 can communicate with a corresponding BluetoothTM communication element 282 of the user device. Although the example of BluetoothTM is provided, it will be appreciated that other forms of suitable communication could be used such as other personal area networks (e.g., ZigbeeTM, Wireless USB, WlFiTM or Near-Field Communication (NEC)). In some examples, wired communication between physical ports of the user device and the wheelchair 2 is used using a physical connection technology such as USBTM, a serial port, or FireWireTM.

The wheelchair 2 also comprises storage 272 to store data used by the wheelchair's control systems. The storage may for example be flash storage (e.g., a solid state drive or a memory card), a hard-disk drive, read-only memory (ROM), erasable programmable ROM (EPROM), and/or electrically erasable programmable ROM (EEPROM). The storage 272 may be used to store a database associating gestures of the gesture controller 40 with movements of the wheelchair, personal discomfort conditions set for the user, and/or information for use by the obstacle detection control unit such as a positioning of the depth camera 50 relative to the wheelchair 2.

Turning now to Figure 2B, there is illustrated a schematic of selected components of a user device that may be used with the wheelchair of Figures 1 and 2A. A user device such as a mobile phone or tablet compute may be used to extend the functionality of the wheelchair 2 and/or provide a more convenient means of interacting with the wheelchair 2.

The user device comprises a processor 280 to perform processing operations. The processor 290 is coupled to a communication element 282 which can communicate with the communication element 274 of the wheelchair 2. As discussed above, a number of possible communication protocols could be used and the form of the communication elements provided will be selected in accordance with the communication protocol by which the user device and the wheelchair 2 are to communicate.

The user device also comprises a speaker 284 which may be used to issue an alert to the user, for example, when the seat control unit 230 determines that the discomfort condition is satisfied or when the obstacle detection control unit 250 identifies an obstacle impassable to the wheelchair 2. The user device is also provided with storage 286, which as described for the storage of the wheelchair 2 may for example be flash storage (e.g., a solid state drive or a memory card), a hard-disk drive, read-only memory (ROM), erasable programmable ROM (EPROM), and/or electrically erasable programmable ROM (EEPROM).

The storage 286 may be used to store user settings such as gesture control profiles or a personalised discomfort condition which can be uploaded to the wheelchair 2.

The user device (e.g., a mobile phone) also comprises a location determining element 288 (such as a GPS receiver element) which can be used to determine the location of the user device and by association the wheelchair 2 and its user. The location may also be communicated via the communication element 282 (e.g., using Bluetooth) to the wheelchair 2. In this way, the user device can be used to provide location information for use in navigation of the wheelchair. Such navigation may take into account obstacles identified by the obstacle detection control unit 250 as impassable (and other impassable obstacles identified for example by other wheelchairs), to direct the user to follow a route suitable for the wheelchair 2.

Figure 3 shows a schematic of a seat monitoring apparatus 300 according to one example. The seat monitoring apparatus 300 itself is adapted to be inserted into a seat such as the seat base 32 or seat back 34 of the wheelchair 2 in Figure 1. The seat monitoring apparatus 300 could also be positioned inside a cushion to be placed on a chair, or inside one of an airplane seat, a seat for a car, a lorry seat, a coach seat or a train seat. Indeed, the seat monitoring apparatus 300 could be used on a wide variety of surfaces where the seat monitoring apparatus 300 can be positioned between the user and the surface. In some examples the seat monitoring apparatus 300 may be placed into the seat or seat cushion at manufacture, (e.g., built into the seat of the wheelchair 2 or a car seat for example), however, in some examples the seat monitoring apparatus 300 is provided separately and can be retrofitted into an existing seat. In this way, even seats that were not originally provided with the seat monitoring functionality discussed herein can be adapted to provide such functionality.

As shown in Figure 3, the seat monitoring apparatus 300 comprises a plurality of sensors 310, 320. These sensors include a centrally positioned temperature and humidity sensor 310. In this example, the temperature and humidity sensors are co-located, however, it will be appreciated that the temperature and humidity sensors could be provided separately. The temperature and humidity sensors 310 provide temperature and humidity readings respectively to the control unit 230. Also provided in the example of Figure 3 are four pressure sensors 320 arranged in four quadrants of the seat monitoring apparatus 300. By arranging the pressure sensors 320 in this way, the weight distribution across the seat can be established and a user's posture identified. Hence, the seat monitoring apparatus 300 is able to establish how the user is sitting and respond accordingly.

Thus, the seat monitoring apparatus 300 is able to make measurements of the temperature, humidity, and pressure in various locations of across the seat. Based on these properties, the control unit 230 coupled to the sensors is able to make a determination as to whether the discomfort condition is satisfied. The discomfort condition may be satisfied based on the measurement from one of the temperature, humidity, and pressure readings, two of these readings, or based on all three of the readings. That is, in some examples, the control unit 230 is configured to determine that the discomfort condition is satisfied in response to any one of the measurements exceeding a preset threshold. In some examples, the discomfort condition is satisfied based on a combination of two of the measurements (e.g., the temperature and humidity each exceeding a threshold), and in some examples the discomfort condition is satisfied based on all types of measurement (e.g., temperature, humidity, and a pressure reading each exceeding a respective threshold). The discomfort condition according to an example will be discussed in more detail with reference to Figure 5.

Irrespective of the form of the discomfort condition, in response to determining that the discomfort condition is satisfied, the control unit 230 is configured to trigger a pre-emptive action. In some examples, this pre-emptive action involves notifying the user that the discomfort condition has been satisfied, for example by issuing an audible alert via speaker 278 or a haptic alert via haptic feedback element 276. Additionally, or alternatively, the user could be notified by issuing a notification to the user device (e.g., the user's mobile phone). By notifying the user, the user could be prompted to adjust their seating position or otherwise address the potential discomfort by moving to a cooler/warmer location or turning on/off the air conditioning, for example. In this way, the user may address the cause of the discomfort proactively to prevent further discomfort or the onset of pressure sores.

In addition to or instead of notifying the user, the control unit 230 may automatically respond to ameliorate the conditions. As shown in Figure 3, the seat monitoring apparatus comprises a heating element 340 and fans 350. Thus, the control unit 230 may be configured to operate either the heating element 340 or the fans 350 in response to determining that the temperature/humidity fall outside acceptable values, thereby returning the temperature and/or humidity towards more comfortable levels. Similarly, as shown in Figure 3, the seat monitoring apparatus 300 comprises actuating elements 330 operable to modify a surface profile of the seat. In this example, the actuating elements 330 are air cells connected to a pump operable to adjust the level of inflation of the air cell. By adjusting the amount of air in each air cell, the surface profile of the seat can be modified, e.g., to shift the user's weight forwards or backwards, as appropriate. Hence, where it is detected that the pressure at a particular pressure sensor 320 is too high, the actuating elements 330 can act to adjust the user's posture thereby shifting the pressure elsewhere to avoid the user developing a pressure sore/feeling discomfort.

Thus, there has been described a seat monitoring apparatus 300 able to respond to detected conditions at the surface of a seat in order to anticipate the onset of pressure sores or other discomfort of the user and pre-emptively respond to alert the user and/or mitigate against the development of pressure sores/discomfort.

Figure 4 shows a seat with which the seat monitoring apparatus 300 of Figure 3 may be used. Part of the seat has been cut-away to show the seat monitoring apparatus 300. The seat comprises a seat base 432 and a seat back 434 although in some examples, the seat may also comprise a head rest and/or arm rests. As shown in Figure 4, the seat base 432 also has a zip fastener 436 with which the seat base 432 can be opened and closed to allow for insertion and removal of the seat monitoring apparatus 300 from the seat base 432. Thus, in this example, the seat monitoring apparatus 300 is removable from the seat and indeed may be retrofitted to the seat.

In some examples, the seat itself is a wheelchair seat for a wheelchair (e.g., of the form depicted in Figure 1). In some examples, however, the seat is an airplane seat, a seat for a car, a lorry seat, a coach seat or a train seat. For all of these seats, it is anticipated that the user will be seated in the seat for an extended period and so will remain seated for sufficient time as to feel uncomfortable in the seat and/or develop a pressure sore due to their seated position. Hence, by making use of the seat monitoring apparatus 300 as discussed herein, such discomfort and/or the onset of pressure sores can be averted or reduced.

The discomfort condition itself make take a number of possible forms. For example, each of the temperature, humidity, and pressure measurements may have their own threshold for which a temperature, humidity, or pressure reading respectively exceeding the threshold would lead to the discomfort condition being satisfied. This approach may be based on an understanding that excessive heat, humidity, and pressure can each individually cause discomfort In some examples, the discomfort condition is based on two of the measured properties or all three of the measured properties exceeding respective thresholds. For example, if both the temperature and humidity are both above particular thresholds, then the control unit 230 may be configured to determine that the discomfort condition is satisfied. This may be based on an understanding that the effect of humidity and temperature for example are interlinked such that how it will feel to sit on the seat will be affected by a combination of temperature and humidity and for example that a cooler temperature may feel warmer than a warmer temperature by virtue of there being a higher humidity at the cooler temperature.

It will be appreciated that several of the above approaches may be combined such that the discomfort condition is satisfied for example in response to one of the measured properties exceeding a threshold or a combination of two or three of the properties exceeding separate thresholds.

Figure 5 is a diagram illustrating conditions under which the discomfort condition is satisfied according to one example. In this example, a pressure sore envelope is defined based on a determined combination of humidity, temperature, and pressure at which the user is likely to be at a heightened risk of developing a pressure sore. As such, when these conditions are detected, the pre-emptive action should be taken in order to prevent or reduce the chance of the user developing a pressure sore. The pressure sore envelope may be set universally for all users based on a general assessment of the conditions under which a user is likely to develop pressure sores or may be set for the particular user, for example, by a healthcare professional, based on an assessment for that user.

As shown in Figure 5, the pressure sore envelope for which the discomfort condition is satisfied corresponds to each of the humidity, pressure, and temperature threshold exceeding a respective threshold. This is because the risk of developing a pressure sore is linked to excessive values of all of these three properties occurring together. As such, when the values of all of these properties each exceed a threshold, the user faces a particular risk of developing a pressure sore and so it is important to respond proactively to prevent the onset of a pressure sore when these conditions are detected.

Figure 6 is a flowchart illustrating a method of monitoring a seat on which a user is sitting according to one example.

At step 602, a temperature, humidity and one or more pressure measurements associated with a user sitting on a surface are taken using the sensors and reported to the control unit 230. Based on these measurements, the control unit 230 then determines whether the discomfort condition is satisfied at step 604. As discussed above, this may for example be determined on the basis of one or more of the measurement values exceeding a threshold or thresholds. If the discomfort condition is satisfied, as illustrated at decision block 606, a pre-emptive action is triggered at step 208. This may involve notifying the user that the discomfort condition has been satisfied and/or taking a proactive step to address the discomfort or the risk of a pressure sore developing represented by the discomfort condition being satisfied. On the other hand, if at decision block 606, the discomfort condition was not satisfied, the method proceeds back to 602. In this way, the control unit 230 can perform constant monitoring of the measurements from the sensors to identify a point at which the discomfort condition is satisfied and respond accordingly.

Claims

CLAIMS1. A seat monitoring apparatus comprising: a plurality of sensors collectively arranged to measure, in use, properties associated with a user sitting on a surface, the plurality of sensors including a temperature sensor, a humidity sensor, and one or more pressure sensors; and a control unit communicatively coupled to the plurality of sensors and configured to determine, based on measurements from the plurality of sensors, whether a discomfort condition is satisfied; wherein in response to determining that the discomfort condition is satisfied, the control unit is configured to trigger a pre-emptive action.
2. The seat monitoring apparatus according to claim 1, wherein the seat monitoring apparatus is configured to be placed into a seat cushion; and the surface is a surface of the seat cushion.
3. The seat monitoring apparatus according to claim 1 or claim 2, wherein: the control unit is configured to determine that the discomfort condition is satisfied when each of a temperature measurement from the temperature sensor, a humidity measurement from the humidity sensor, and a pressure measurement from the one or more pressure sensors satisfies a respective threshold.
4. The seat monitoring apparatus according to any preceding claim, wherein: the control unit is configured to determine that the discomfort condition is satisfied when a measurement from any sensor of the plurality of the sensors satisfies a threshold for that sensor.
5. The seat monitoring apparatus according to any preceding claim, wherein: the discomfort condition is a pressure sore condition and the control unit is configured to determine that the discomfort condition is satisfied when the measurements from the sensors indicate a heightened risk to the user of developing a pressure sore.
6. The seat monitoring apparatus according to any preceding claim, wherein: the control unit is configured to receive an input indicative of a new discomfort condition and to use, as the discomfort condition, the new discomfort condition; wherein the discomfort condition is set based on characteristics of the user.
7. The seat monitoring apparatus according to any preceding claim, wherein: the pre-emptive action comprises issuing an alert to the user.
8. The seat monitoring apparatus according to claim 7, wherein: the seat monitoring apparatus comprises an output element and the control unit is configured to issue the alert to the user via the output element.
9. The seat monitoring apparatus according to claim 8, wherein: the output element comprises at least one of a speaker and a hapfic feedback 10 element.
10. The seat monitoring apparatus according to claim 7, wherein: issuing the alert comprises triggering a notification at a mobile device.
11. The seat monitoring apparatus according to any preceding claim, wherein: the control unit is configured to store the measurements from the plurality of sensors; and the seat monitoring apparatus further comprises a communication element arranged to transfer the stored measurements to a separate device.
12. The seat monitoring apparatus according to claim 11, wherein: the control unit is configured to selectively store sets of measurements for a period during which the discomfort condition is satisfied.
13. The seat monitoring apparatus according to any preceding claim, wherein: the seat monitoring apparatus comprises one or more actuating elements operable by the control unit to modify a profile of the surface; and the pre-emptive action comprises initiating a change in the user's posture by modifying the profile of the surface.
14. The seat monitoring apparatus according to claim 13, wherein: the one or more actuating elements comprise air cells controllable by the control unit, wherein triggering a change in an inflation level of one or more of the air cells by the control unit causes modification of the profile of the surface.
15. The seat monitoring apparatus according to claim 13 or claim 14, wherein: the plurality of sensors includes a plurality of pressure sensors, each of the plurality of pressure sensors associated with a position on the surface; when the measurements from the plurality of pressure sensors indicate that a pressure at a particular position on the surface exceeds a pressure threshold, the control unit is configured to trigger, as the pre-emptive action, control of the actuating elements to modify the user's posture to a new posture determined by the control unit to reduce a pressure imparted by the user at the particular location.
16. The seat monitoring apparatus according to any preceding claim, wherein: the seat monitoring apparatus comprises a heating element operably by the control unit; and when the measurements from the temperature sensor indicate a temperature below a minimum temperature threshold, the control unit is configured to trigger, as the preemptive action, the heating element to heat the surface.
17. The seat monitoring apparatus according to any preceding claim, wherein: the seat monitoring apparatus comprises a cooling element operably by the control unit; and when the measurements from the temperature sensor indicate a temperature above a maximum temperature threshold, the control unit is configured to trigger, as the pre-emptive action, the cooling element to cooling the surface.
18. The seat monitoring apparatus according to claim 17, wherein: the cooling element is a fan.
19. The seat monitoring apparatus according to claim 2, wherein: the seat cushion is a seat cushion of a wheelchair seat.
20. The seat according to any of claim 2, wherein: the seat cushion is a seat cushion of one of: an airplane seat; a seat for a car; a lorry seat; a coach seat; and a train seat.
21. A method of monitoring the comfort of a user sitting on a surface, the method comprising: measuring, using a plurality of sensors, properties associated with a user sitting on a surface, wherein the plurality of sensors include a temperature sensor, a humidity sensor, and one or more pressure sensors; determining, based on measurements from the plurality of sensors, whether a discomfort condition is satisfied; and in response to determining that the discomfort condition is satisfied, triggering a preemptive action.
22. A wheelchair comprising the seat monitoring apparatus of any of claims 1 to 19.
23. A seat cushion for monitoring the comfort of a user, the seat cushion comprising: a plurality of sensors collectively arranged to measure, in use, properties associated with a user sitting on a surface, the plurality of sensors including a temperature sensor, a humidity sensor, and one or more pressure sensors; and a control unit communicatively coupled to the plurality of sensors and configured to determine, based on measurements from the plurality of sensors, whether a discomfort condition is satisfied; wherein in response to determining that the discomfort condition is satisfied, the control unit is configured to trigger a pre-emptive action.