WO2007120099A1

WO2007120099A1 - A tablet control device for controlling a wheelchair

Info

Publication number: WO2007120099A1
Application number: PCT/SE2007/000351
Authority: WO
Inventors: Hans Fraeyman; Victor Claes
Original assignee: Permobil Ab
Priority date: 2006-04-13
Filing date: 2007-04-13
Publication date: 2007-10-25
Also published as: SE0600839L

Abstract

The invention relates to a tablet control device 1 for controlling a wheelchair (10). The tablet control device (1) comprises a casing (2) mountable to the wheelchair (10) and having an upper surface (3). The tablet control device (1) comprises a number of capacitive sensors S1,&mldr;,Sn arranged within the casing (2) for sensing the position of an object placed on the upper surface (3). A central processing unit is arranged to obtain information from the sensors S1,&mldr;,Sn and execute in dependence thereon a desired control operation for controlling the operation of the wheelchair (10).

Description

A tablet control device for controlling a wheelchair

Field of the invention

The invention relates to the field of wheelchairs, and in particular to improved means for controlling a wheelchair. Further, the invention relates to a wheelchair comprising such improved control means .

Background of the invention

People with physical disabilities often encounter difficulties when trying to perform operations requiring some degree of precision. For example, many persons find it difficult to use a standard joystick to control a wheelchair due to various physical handicaps. Another example is the controlling of a computer, i.e. the use of a computer input device, such as a mouse. On the whole it is often difficult for physically handicapped people to manoeuvre handheld pointing devices .

The difficulties manifest themselves in different ways. Some persons are not able to grasp the handle of a joystick, but are nevertheless able to move the hand in a rather controlled way when the hand is placed on a surface. Other persons may have unpredictable and spastic movements when the hand and arm are not supported by some support means , i.e. while holding the arm in the air. These persons may very well be able to move the hand over a surface once the hand comes in contact with a fixed surface, such as a table. These movements may be more or less controlled. However, the location of the first contact with the surface is most often unpredictable and will differ unpredictably from a previous location. Form the above it is clear that the provision of a control device adapted for and suitable for persons having different kinds of disabilities would be desirable.

Summary of the invention

It is an object of the invention to provide an improved input device for controlling a wheelchair or the like. More specifically, it is an object of the invention to facilitate, for people with different disabilities, the operation of a wheelchair.

It is another object of the invention to provide an input device for controlling a wheelchair suitable for a wide range of different user groups.

These objects, among others, are achieved by a tablet control device for a wheelchair as claimed in claim 1.

In accordance with the invention, a tablet control device for controlling a wheelchair is provided. The tablet control device comprises a casing mountable to the wheelchair and having an upper surface. The tablet control device comprises a number of capacitive sensors arranged within the casing for sensing the position of an object placed on the upper surface. A central processing unit is arranged to obtain information from the sensors and execute in dependence thereon a desired control operation for controlling the operation of the wheelchair. By utilising capacitive sensors a high accuracy of the position of the object, such as a hand or finger, is obtained. Further, capacitive sensors can measure and image objects without the object touching the surface. For example, when a hand is used for controlling the wheelchair, only fractions of the hand will actually be in direct contact with the surface, while the rest of the hand will be close to the surface. The sensors are still able to detect the entire hand, which is in range so that the whole object can be imaged. This makes them very suitable for use in controlling a wheelchair, especially for persons having lowered strength. Further yet, the use of capacitive sensors also renders the control device suitable for people with different kinds of disabilities.

In another aspect of the invention, the tablet control device further comprises means for controlling peripheral equipment, such as a robot arm mounted to the wheelchair or remote devices such as a computer or the like. The tablet control device may also comprise means for controlling the backrest or headrest or the like of the wheelchair. A flexible and multifunctional tablet control device is thus provided, enabling a user to comfortably control other devices as well.

Further objects of the invention and advantages thereof will become clear from the following description.

Brief description of the drawings

Figure 1 shows, in a front view, an embodiment of the control device in accordance with the invention.

Figure 2 shows, in a view from below, the control device according to an embodiment of the invention.

Figure 3 illustrates an arrangement of sensors S₁ in a control device in accordance with the invention.

Figure 4 illustrates a layout of an exemplary set-up overlay to be used in the control device in accordance with the invention.

Figure 5 shows a stacked PCB configuration within a control device in accordance with the invention. Figure 6 illustrates a control device in accordance with the invention mounted on a wheelchair.

Figure 7 illustrates in an exploded view the constituent parts of the control device in accordance with the invention.

Figures 8a-8g illustrate schematically software design for an input task.

De-bailed description of preferred embodiment:s

In designing a control device in accordance with the present invention, a number of limitations and specifications were taken into account. The aim was to provide an improved control device for controlling a wheelchair or the like making it suitable for a plurality of different user groups.

In accordance with the specifications it was also a desire to enable a user to use any other part of the body to control the device, for example a foot, an elbow, a chin or the like.

In accordance with the invention, the position of a user's hand on a control device surface should be measured or captured in an improved way for achieving the above mentioned goal of enabling different user groups to use the control device. The position of the hand or any body part on a surface should be determined. In the following description it is assumed that a hand is to be used for the control operations, but any other body part could be used as well.

In the following, some of the considerations taken into account when designing the inventive control device will be described. Firstly, the position of the hand should be determined irrespective of how the hand is held. That is, the user should be able to hold his hand in any desired position, for example flat or clenched fist or upside down.

Secondly, the output of the control device should preferably be fully proportional to the distance travelled by the hand. That is, moving the hand a certain distance on the surface should result in that the wheelchair increases its speed some corresponding amount. Alternatively, the distance travelled could be semi-proportional to the distance.

Thirdly, the further the hand is moved from an initial point of contact, hereinafter called origin, the faster the wheelchair will drive. The origin is preferably defined as the location where the hand first touches the surface of the control device. The origin should therefore be variable and dependent on the first contact of the hand with the surface of the control device.

Fourthly, since disabled persons often have reduced strength the required activation force to be applied to the surface of the control device should be very small or even zero. Just cursorily touching the surface should be enough to activate the control device.

Fifthly, the control device should be very durable and strong because of the high impacts it may be subjected to and has to withstand if used by a spastic user. Further, since the control device is arranged on a wheelchair it should withstand any weather condition.

Sixthly, the control device has to comply with Harmonised standards applicable for wheelchair control systems. In order to be able to fulfil at least some and preferably all the above-mentioned specifications, the inventors of the present invention have pinpointed and realised one way to improve the controlling of a wheelchair and make it suitable for a wide range of users. More specifically, the inventors have realised that there are very favourable advantages to be obtained in utilising a different kind of sensors than presently used within wheelchair control devices.

A control device in accordance with the invention will now be described with reference first to figure 1, which shows the inventive control device in a front view. The control device is a tablet control device, denoted simply "control device" in the following. The control device 1 comprises a casing 2 having an upper part and a lower part and is, for example, made of plastic or some other durable material. The control device 1 is preferably square-shaped, but any other shape is conceivable, for example a circular or semicircular shape. The upper surface 3 of the control device 1 is preferably flat, since a flat surface is most comfortable for a user and enables an uncomplicated arrangement of the sensors to be used (to be described below) . The control device 1 further comprises a central processor (not shown) for processing, among other things, input signals.

Figure 2 shows the control device of the previous figure from a view underneath. The lower surface of the control device 1 is designed so as to enable a suitable and secure mounting to a wheelchair. Further, fastening means 4, 5, 6 are included for fastening the control device 1 to the wheelchair in a most secure manner.

In the control device 1 in accordance with the invention, the sensors used are of an electrically sensitive type, that is, of a capacitive type. Capacitive sensors must be affected with a conductive device, such as a hand or a finger, unlike resistive and surface wave panels that can use anything that can point, such as a finger or stylus. The upper surface 3 of the control device 1 is thus a capacitive touch sensitive surface. The capacitive sensor to be used within the control device 1 could be of a type that can measure the distance to an object, or of a type that can detect when an object is close enough. This can be very advantageous in that a user can control the wheelchair with zero activation force, that is, the hand needs only be close enough for the sensors to detect it, which could be a few millimeters . A user having a severely lowered strength can thereby use the control device 1 even without actually touching it. Since the capacitive sensors can measure and image objects without the object touching the surface, they are very suitable for use in controlling a wheelchair, especially for persons having lowered strength. For example, when a hand is used for controlling the wheelchair, only fractions of the hand will actually be in direct contact with the surface, while the rest of the hand will be close to the surface. Despite of this lack of contact, an image of the whole hand can be provided.

Briefly, switched-capacitance sensing or charge-transfer sensing ("QT) uses electronic switches to charge a sense plate of unknown capacitance to a known potential, and transfer the resulting charge into a measurement circuit. By measuring the charge after one or more charge-and-transfer cycles, the capacitance of the sense plate can be determined. The charge-transfer-acquisition process is carried out in burst mode using microprocessor-controlled switching of MOSFET transistors. This makes it possible to monitor small changes in capacitance to determine if something has approached or touched the sensing surface. QT technology is more stable and more accurate than other types of capacitive sensing.

The upper surface 3 may consist of a number of contact surfaces, also called . keys, in the following denoted sensors. Each key consists of two electrodes, one pulse driven electrode and one charge-receiving electrode. Charge is pumped from one electrode to the other and disturbances in the amount of charge received are detected and used for detecting touches. That is, each key can be considered as a contact, which will switch (close) if a conductive object comes close enough to the surface 3. No actual contact is thus necessary. The electrodes could be arranged in rows and columns. For example, 10 electrode lines arranged along the x-axis overlying 10 electrode lines arranged along the y- axis would provide 100 possible keys for use.

Figure 3 illustrates the control device 1 of figure 1 with the upper part of the casing 2 removed. Under the casing 2, i.e. within the control device 1, a number of sensors S₁,..., S_n are arranged. Any number of sensors can be used, and in the figure only a few sensors are shown. The number of sensors S₁ included within the control device 1 determines how well the control device 1 is able to read the image of the hand. That is, the number of sensors S₁ defines the accuracy of the control device 1. To obtain an acceptable accuracy of the output, an array of at least 12 by 10 sensors should be used, i.e. a total of 120 sensors. In order to provide a higher accuracy, a higher number of sensors could be used, for example 16 by 12 (192 in total). Even larger number of sensors could be used, or a fewer number of sensor. The number of sensors could be adapted in accordance with special requirements of a certain user group, and it is realized that the more sensors the higher the accuracy, but at the cost of increased manufacturing costs. Lowering the number of sensors also lowers the accuracy of the control device.

In a preferred embodiment 192 sensors are used. The number chosen is based on test performed for different layouts and it has been found that there is a trade-off at 192 sensors. More sensors just increase the price but without essentially improving the drive performance and less sensors caused lower drive performance.

In the preferred embodiment the capacitive sensors are of the above-described switched type, since switched sensors are less sensitive to environmental conditions than other types of capacitive sensors making it suitable for outdoor use. By means of switched sensors an image of the hand on the surface 3 is provided, as is described more in detail later.

As mentioned earlier, the control device 1 is preferably square-shaped. The size of the surface of the control device should be chosen in consideration of the different types of users. On the other hand, the size of the surface should not be unnecessarily large, thereby keeping the space requirements and costs at a minimum. An adequate size is between about 200 mm and 250 mm in one direction and between about 275 mm and 325 mm in the other direction. The invention is not limited to the sizes indicated, and specific user groups could be addressed and for them a larger or smaller surface could be more suitable. Control devices having surfaces of any size is conceivable. Further, the thickness and weight of the control device should also be adequately chosen. The control device should be suitable for being built into the table of a wheelchair, and should therefore not be too heavy. As an example, the weight should be less than 1 kg and an adequate thickness is 35 mm or less.

There are integrated electronic circuits available on the market, which integrate several capacitive sensors into one package. An example of such an integrated circuit, suitable for use in the inventive control device, is QT60486 from QUANTUM. The QT60486 has a total of 48 sensors, and in an embodiment of the invention four such integrated circuits were utilised, giving a total number of 192 sensors. This provides a very satisfactory accuracy and reliable controlling of the wheelchair. The QT60486 circuit is only an exemplary device; other types of capacitive sensors could be used.

A central processing unit (not shown), in the following simply "central processor", communicates with all the sensors or sets of sensors. The central processor is connected to the electronics of the sense array by means of a serial communication protocol. The main processor can read every sensor separately and preferably does this with a regular interval. From that information, software in the processor will create a bitmap image of the body part or device used to control the wheelchair that is close enough to the sensors. The processor is also connected to one or two additional external push buttons. These buttons can be used to improve safety of the system, for example used as an emergency switch, or add additional user interface possibilities. If an additional button is used as an emergency stop, the wheelchair is arranged to stop whenever the button is pressed. The processor also prepares drive signals based on the signals from the sensors. The drive signals are then sent to the wheelchair in order to control it. An exemplary processor suitable for use in the control device is Atmel AVR series. The communication between the central processor and the sensors is performed over a digital communication bus. Software in the main processor will determine the shape and size of the hand and calculate the output signals. In the calculations predefined parameters, such as rotation/mirror axis and amplification, are taken into account. For example, a left/right amplification, or X amplification, can be a parameter that can be set. The distance between a locked neutral point and a mass point, along the x-axis, can provide the maximum driving speed of the wheelchair. The higher the x- amplification value, the faster the maximum driving speed is reached, in the x-direction. Two sequential speed steps thus have more impact on the driving speed when the amplification value is increased. A corresponding y-amplification can be provided. Further, calibration data, data collected during the production are also taken into account.

Since the control device, in a preferred embodiment, is used for controlling a wheelchair, it is realised that the control device is safety critical. All necessary measures must be taken to make the device as safe as possible.

Finally, the control device should be compatible with several types of wheelchair electronics, such as DX, PILOT+ and Easy Rider. Any other communication bus standard can of course be used, for example USB (universal serial bus).

A built-in set-up is provided so that the control device can easily be reconfigured according to the specific needs of the user. This set-up is preferably done without the need to connect the control device to an external device, such as a programmer or computer. Some of the reconfigurable parameters of the set-up include: rotation and mirroring of the output signals (x-axis and y-axis of the control device); separate setting of the amplification of the x-axis and y-axis (this will set the relation between the output of the control device); and the distance travelled by the hand; sensitivity of the sensors, etc.

The output of the control device should preferably be fully proportional to the distance travelled by the hand. That is, moving the hand a certain distance on the surface should result in that the wheelchair increases its speed some corresponding amount. Alternatively, the distance travelled could be semi-proportional to the distance. The further the hand is moved from the origin, the faster the wheelchair will drive. The origin should therefore be variable and dependent on the first contact of the hand with the surface of the control device. In some wheelchairs separate input devices are used for controlling the speed and for controlling the direction. The controlling of speed and direction can be performed in conventional manner.

The software used in the control device must be secure, flexible and easy to understand. It should support a production mode and the control device is then connected to a PC. It is then possible to automatically test and calibrate the hardware. All calibrate data is stored in an

EEPROM (Electrically-Erasable Programmable Read-only Memory) of the control device.

Further, the software should support an end-user set-up mode. That is, a mode in which the user can easily change some parameters in dependence on his or hers special needs, or simply select the production default settings. Entering the set-up mode should be as easy as possible, involving a minimum of steps. For example, by pushing a special set-up button at the backside of the control device while switching on the control device, the system is put into set-up mode.

An overlay is used, and placed on top of the device. An exemplary layout of an overlay for the set-up is shown in figure 4. By touching the different keys on the overlay the user can easily and quickly make the desired changes. Switching off the device will result in leaving the set-up mode, although other arrangements for switching between different modes are conceivable. It is understood that the overlay shown in figure 4 is only an example of a possible overlay. The layout can of course be changed in accordance with the functions provided by the software .

The sensors S₁ are arranged on an upper PCB (Printed Circuit Board) 7_a, as is illustrated in figure 5. Preferably, no active electronics are mounted on this PCB 7_a. The second, lower PCB 7_b comprises all such active electronics. This stacked PCB configuration is preferred in order to minimize possible disturbances on the sensors S₁,..., S_n from the active electronics. That is, there should be sufficient distance between the sensors and the active electronics in order for the sensors to provide an accurate and reliable measurement. Also in view of minimizing the size of the PCB, the above- described solution is preferred. However, a solution with a single PCB is conceivable, provided the arrangement of the sensors and the active electronics and connection lines can be made in an adequate manner.

The control device has an active mode and a standby mode. When the hand of a user has not been in contact with the surface for a predefined time, the control device preferably enters a standby mode. The standby mode should not be entered immediately upon the lifting of a hand, i.e. the predefined time should not be set to zero, because a user having spastic movements may unintentionally lift his or hers hand for a very short duration. The control device in accordance with the invention is thereby suitable for a wide variety of users. In the standby mode, when the hand touches the surface of the control device and has been sufficiently stable for a second predefined time, the current position of the hand is registered as the origin and thereafter the control device enters an active mode.

If and whenever a fault is detected, the control device should enter a safe mode. In the safe mode the output will return to neutral causing the wheelchair to stop.

Further yet, in order to determine the coordinates of the hand on the surface, the principle of calculating the mass point of the read image is utilised, which is described somewhat more in detail with reference to figures 8a-8g. By subtracting these coordinates from the origin, the output of the control device is set. However, in tests it has been shown that the user in many cases puts the hand and part of the arm on the surface of the control device. When the hand is moved backwards, the arm is lifted. This alters the image completely. Therefore, some kind of image handling is included before calculating the mass point. This problem could be solved by using only a predefined number of lines starting at the top of the image, the number of lines being part of the set-up settings. This solution will remove part of the images caused by the arm. However, more elaborated techniques could be used in order to improve the quality of the mass point calculations.

Figure 6 illustrates the control device 1 in accordance with the invention in use, i.e. mounted on a wheelchair 10. In the figure the most preferred placement of the control device 1 is shown. However, other placements of the control device 1 are of course conceivable. For example, it could be mounted on one of the armrests 11, 12, and bent outwards. For a right-handed user, the control device 1 should thus preferably be mounted on the right-hand armrest 11. If another part of the body is to be used in the steering of the wheelchair 10, for example a foot, the control device 1 is placed accordingly.

Figure 7 illustrates in an exploded view the constituent parts of the control device 1. Upper and lower sides of the casing 2 enclose the core of the control device, i.e. the sensors and electronics.

Finally, figures 8a-8g illustrate schematically an exemplary software design for an input task. The keys (sensors) are read and the values stored in a bitmap in a memory of the processor. Software manipulations on that bitmap are performed and the processor calculates a drive signal for an output task.

In figure 8a, keys that have detected a presence of a hand or the like are marked with an X. A minimum number of touched keys may be set, so that if less keys than the set number are touched this is interpreted as no object (e.g. body part) is touching the surface.

In figure 8b, the uppermost touched line is determined ( shaded area ) , i.e. the uppermost active line . The number of active lines can be a parameter setting the number of horizontal key lines, which defines an active window. The parameter can be used to disable the influence of touched keys beneath the active window in the mass point calculation, which may be caused by for example an arm.

In figure 8c, unwanted keys are eliminated. According to the chosen number of active lines, starting from the uppermost active line (figure 8b), the number of touched keys within the active window (shaded area of figure 8c) are used to calculate the general mass point. All other touched keys outside this active window are ignored. In the illustrated case, the active window contains 7 active lines and within the active window there are 8 touched keys. The general mass point, indicated by M, is calculated as the average x- and average y-values of all touched keys within the active window. There may be a parameter, Tremor, which can be suitably set. This parameter is the maximum distance between the first mass point, calculated just after putting the object on the tablet surface and the following mass points before a neutral point is calculated and locked. This means that the jitter course of a touched body part should not deviate more than the maximum tremor value before a neutral point is locked.

In figure 8d, the mass point is used as reference point. If the mass point M is held for a sufficient time, which could be a suitably set time, the mass point M will be locked as the actual neutral point N.

In figure 8e, if the mass point M is displaced by moving the touched object in any direction on the table surface, while the neutral point N is locked, the wheelchair will drive in accordance with the chosen displacement direction. In figure 8e, the arrow indicates the wheelchair direction.

In figure 8f, if the mass point M is released, which could happen if not enough keys are touched anymore, while the wheelchair is driving, then the displaced mass point will disappear. This results in an immediate and unconditional stop of the wheelchair, as illustrated in the figure by the absence of an arrow. The neutral point N is however still active and locked. The active window still exists since there are still touched keys, but the number of touched keys in the active window is not enough to keep the previous mass point M alive.

Finally, in figure 8g, if the mass point M is released after the neutral point N is locked, the neutral point will be unlocked after a predefined elapsed time frame. This mechanism allows for the release of the hand shortly from the surface of the tablet without loosing the neutral point

N. This feature is particularly advantageous in view of users having spastic movements.

In another embodiment the control device 1 is compatible with a computer input, and the control device that is used in order to control a wheelchair 10 may also be used in order to control a computer.

In another aspect of the invention, the tablet control device 1 comprises means for controlling accessories, peripheral equipment or surrounding equipment. That is, the tablet control device 1 is used not only for controlling or driving the wheelchair 10, but also peripheral devices such as for example an environmental control systems such as air conditioning, seat adjustment of the wheelchair, information systems, infotainment systems, a robot arm connected to the wheelchair, a computer etc. The peripheral equipment may thus be controlled remotely from the same tablet control device 1 that is used for controlling the movements of the wheelchair 10. Peripheral devices mounted to the wheelchair 10 may also be controlled in this way.

In an embodiment of this aspect of the invention, the tablet control device 1 is used for controlling a robot arm mounted on the wheelchair 10. Such robot arm could be used for assisting the user in reaching objects otherwise out of reach of the user. The tablet control device 1 could also be used for adjusting the backrest, headrest, footrest, armrest, rear view mirrors or the like of the wheelchair.

In another embodiment of this aspect of the invention, the tablet control device 1 comprises a Bluetooth device or an IR (infrared) device or some other short-range communication means for transmitting and receiving information from another device comprising corresponding short-range communication means. For example, the tablet control device 1 can be used for inquiring information from a thermometer and displaying the information on a display of the wheelchair 10. It is to be noted that it is also conceivable to include means for long-range communication means.

Software suitable for controlling the different peripheral equipments could be added to the tablet control device 1.

Means, such as a button, for causing the wheelchair electronics to switch from controlling the movements of the wheelchair 10 to controlling peripheral equipment could be added to the tablet control device 1. Further, if remote devices are to be controlled, then also suitable communication means should be added, such as Bluetooth devices .

Claims

1. A tablet control device (1) for controlling a wheelchair (10), said tablet control device (1) comprising a casing (2) mountable to said wheelchair (10), said casing (2) having an upper surface (3), characterised in that said tablet control device (1) comprises a number of capacitive sensors (S₁,..., S_n) arranged within said casing (2) for sensing the position of an object placed on said upper surface (3), and in that a central processing unit is arranged to obtain information from said sensors (S₁,...,S_n) and execute in dependence thereon a desired control operation for controlling the operation of the wheelchair (10).

2. The tablet control device (1) as claimed in claim 1, wherein said object is a part of the body of a user, such as a hand or foot.

3. The tablet control device (1) as claimed in any of the preceding claims, wherein said control operation is the controlling of the speed and direction of said wheelchair (10).

4. The table control device (1) as claimed in claim 3, wherein said speed is increased in proportion to the movement of said object.

5. The tablet control device (1) as claimed in any of the preceding claims, wherein the output of the control device (1) is proportional to the distance travelled by the object.

6. The tablet control device (1) as claimed in any of the preceding claims, wherein an origin is defined as the location where said object first touches the surface (3) of the control device ( 1 ) .

7. The tablet control device (1) as claimed in claim 6, wherein the central processor is arranged to adapt the speed of the wheelchair (10) in relation to the distance travelled by said object from said origin.

8. The tablet control device (1) as claimed in claim 7, wherein the central processor is arranged to increase the speed of the wheelchair (10) the further from the origin said object moves.

9. The tablet control device (1) as claimed in any of the preceding claims, wherein said central processor comprises means for assuming different modes of operation.

10. The tablet control device (1) as claimed in claim 9, wherein said modes of operation comprise one or more of: a standby mode, an active mode, a set-up mode, and a safe mode.

11. The tablet control device (1) as claimed in any of the preceding claims, further comprising means for detecting a fault, whereupon said tablet control device (1) is arranged to enter a safe mode, in which the output will cause the wheelchair (10) to stop.

12. The tablet control device (1) as claimed in any of the preceding claims, wherein said tablet control device (1) is compatible with several types of wheelchair electronics.

13. The tablet control device (1) as claimed in any of the preceding claims, wherein said capacitive sensors (S₁,..., S_n) are of a switched type.

14. The tablet control device (1) as claimed in any of claims 1-13, wherein said capacitive sensors (S₁,...,S_n) are able to detect determine the distance to an object.

15. The tablet control device (1) as claimed in any of the preceding claims, further comprising means for controlling a peripheral device mounted to said wheelchair (10).

16. The tablet control device (1) as claimed in any of the preceding claims, further comprising means for remote control of one or more peripheral equipment.

17. The tablet control device (1) as claimed in any of the preceding claims, further comprising means for controlling different parts of said wheelchair (10) such as the armrest, the footrest, the backrest or the neck rest.

18. A wheelchair comprising a tablet control device (1) as claimed in any of the preceding claims.