Multi-zone control interface for electric mobility

Abstract

Control interface (100) for controlling an electrically powered wheelchair, comprising an input unit (110) for determining a user input on the control interface, a calculation unit (120) for calculating a direction of travel and a speed of the wheelchair on the basis of a user input made via the input unit (110), a control unit (130) designed to separately control two independent main wheels of the wheelchair on the basis of a direction of travel and speed calculated by the calculation unit (120), wherein the input unit has a separate, flat first zone (101) which is designed to generate a signal for causing the wheelchair to come to a standstill upon a user input in this first zone, and / or wherein the input unit has a separate, flat second zone (102, 103) which is designed to generate a signal for causing the wheelchair to turn on the spot upon a user input in this second zone, wherein the input unit (110) has a separate, flat third zone (104) which is designed to generate a signal for causing the wheelchair to reverse upon a user input in this third zone, wherein the input unit (110) has a separate, flat fourth zone (105) which is designed to generate a signal for causing the wheelchair to move forward when a user input is made in this fourth zone, wherein the third zone (104) and / or the fourth zone (105) on the input unit (110) each have a minimum width, wherein a change in the position of the user input within the minimum width of these zones does not result in a change in the direction of travel of the wheelchair.

Description

[0001] The invention relates to a method and a device for controlling an electric wheelchair by means of a touch-sensitive control interface.

[0002] When controlling an electrically powered wheelchair or other self-propelled electric mobility devices, there are various options for the control interface that processes user inputs. On the one hand, joysticks are used: small levers that are deflected from a central rest position. The speed of the wheelchair is determined by the degree to which the joystick is deflected forwards or backwards, and the direction of travel of the wheelchair is determined by the deflection of the joystick to the sides. On the other hand, touchpads or touchscreens can be used: touch-sensitive surfaces where the control signals result from the position of the user input on the touch-sensitive surface. Starting from a central position on the touchpad, the speed of the wheelchair is calculated from the distance forwards or backwards.backwards from a position of a user input on the touchpad to the central position. The direction of travel of the wheelchair can be calculated from the lateral distance or the angle of the position of the user input on the touchpad to an imaginary center line. The wheelchair can be stopped by ending the user input on the control interface, for example when the user lifts their finger from the touchpad. Alternatively, it is also possible to move the finger to the central resting position on the touchpad. Small deviations from the resting position then lead to small movements of the wheelchair, making it difficult to stop the wheelchair completely. Likewise, when the wheelchair is traveling straight ahead, small deviations in the user input on the control interface to the side lead to a deviation of the wheelchair's direction of travel from straight ahead.Simply maintaining the desired direction of travel in a straight line is difficult. Turning on the spot with the smallest possible turning radius also presents the user with difficulties. Maneuverability similar to that of a manually propelled wheelchair with, for example, counter-rotating main wheels is virtually impossible. However, this is a significant advantage for a wheelchair that is largely used in tight, winding interior spaces.

[0003] US 7 971 893 B1 discloses a wheelchair comprising a chair element consisting of a seat portion with a backrest portion extending vertically therefrom. On each of the two opposite sides of the backrest is an armrest that pivots between a horizontal, extended position during use and a stowed, vertical position when a patient enters or exits the seat. The chair is mounted on an electronics housing containing a pair of reversible DC motors and associated gears that drive a pair of pneumatic tires. A caregiver can stand on a platform behind the chair element while operating the wheelchair. The speed and direction of the wheelchair are controlled using two control panels.The caregiver control panel is mounted on a handlebar attached to the back of the backrest, while the patient control panel is mounted on one of the armrests.

[0004] US 2004 / 0 220 704 A1 discloses an eye-controlled driving system that is controlled by the user's eye. The system is suitable for disabled or elderly people, allowing them to easily drive a motorized vehicle. The system essentially consists of a display device, a gaze detection device, a computing device, a control device, and a motorized vehicle. The system can capture an image around the user's eye and then determine the pupil center. The vehicle can be controlled based on the position of the pupil center. It is therefore an object of the invention to provide an improved control system for electrically powered wheelchairs.

[0005] The object is achieved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the following description, and the figures.

[0006] According to a first aspect of the invention, a control interface for controlling an electrically powered wheelchair is provided, wherein the control interface comprises: an input unit for determining a user input on the control interface, a calculation unit for calculating a direction of travel and a speed of the wheelchair based on a user input made via the input unit, and a control unit designed to separately control two independent main wheels of the wheelchair based on a direction of travel and speed calculated by the calculation unit, wherein the input unit has a separate, flat first zone designed to generate a signal for causing the wheelchair to stop upon a user input in this first zone, and / or wherein the input unit has a separate, flat second zone,which is designed to generate a signal for causing the wheelchair to turn in place upon a user input in this second zone. The input unit has a separate, flat third zone, which is designed to generate a signal for causing the wheelchair to reverse upon a user input in this third zone. The input unit has a separate, flat fourth zone, which is designed to generate a signal for causing the wheelchair to move forward upon a user input in this fourth zone. The third zone and / or the fourth zone each have a minimum width on the input unit, whereby a change in the position of the user input within the minimum width of these zones does not result in a change in the direction of travel of the wheelchair.

[0007] In a control interface according to the invention for an electrically powered wheelchair or for similar self-propelled electric vehicles, a touchpad or touchscreen, for example, is used as an input unit for capturing user input. This task can also be performed by any commercially available mobile phone with a touch-sensitive display and the appropriate installed application program. The input unit can also be spatially separated from the computing unit or control unit and communicatively coupled via a cable, Wi-Fi, or near-field connection. Control via a joystick or similar device can also exhibit the functions of the control interface according to the invention, in that the joystick position replaces the position of a finger on the touchpad or touchscreen.With a corresponding control interface, the position of the user input on the input unit, for example either a touch on a touchpad or a touchscreen or the position of a joystick, is determined and from this the desired direction of travel and speed are calculated by a calculation unit.

[0008] The direction of travel can be determined, for example, from the lateral distance or angle of the position of the user input on the touchpad to an imaginary center line. In the context of the present invention, the direction of travel should be understood as the steering angle, or more precisely, as the ratio of the rotational speeds of the two main wheels of the wheelchair. The speed of the wheelchair can be determined, for example, from the distance of a position of a user input on the touchpad to a central center position.

[0009] Based on the desired direction of travel and speed, a control unit separately transmits the respective speed, direction of rotation, and acceleration to the motors of the wheelchair's two main wheels. Advantageously, the input unit has separate zones with a specific spatial extent that are optimized for special driving situations. The first such zone serves as the rest position. A user input in this first zone leads to a complete standstill of the wheelchair, i.e. both main wheels should come to a complete standstill. The finite spatial extent of the zone also allows for a slight variation in the position of the user input without leaving the zone. This enables comfortable, reliable stopping of the wheelchair even with imprecise user input, without the user having to release contact with the input unit.The second separate zone is used for turning on the spot or cornering with the tightest possible radius. A user input in this zone results in the inside wheel coming to a complete stop while the outside wheel continues to rotate, or in the opposite direction, allowing for particularly tight turns and even turning on the spot.

[0010] According to the invention, the input unit has a separate, flat third zone which is designed to generate a signal for causing the wheelchair to travel backwards when a user input is made in this third zone.

[0011] This third separate zone on the input unit is used, for example, for straight-line reversing. In this embodiment, a user input in this third zone results in both main wheels of the wheelchair rotating backward at the same speed. This enables comfortable, reliable reversing of the wheelchair.

[0012] According to the invention, the input unit has a separate, flat fourth zone which is designed to generate a signal for causing the wheelchair to move forward when a user input is made in this fourth zone.

[0013] This fourth separate zone on the input unit is used, for example, for straight forward travel. In this embodiment, a user input in this fourth zone results in both main wheels of the wheelchair rotating forward at the same speed. This enables comfortable, reliable forward travel of the wheelchair.

[0014] According to the invention, the third and / or fourth zone on the input unit each have a minimum width, wherein a change in the position of the user input within the minimum width of these zones does not lead to a change in the direction of travel of the wheelchair.

[0015] The finite spatial extent of these zones in this embodiment allows for slight variations in the position of the user input without leaving the zone, thus providing a signal to navigate, for example, a curve. This prevents the wheelchair from lateral deviations from the desired course, even with imprecise user input, enabling comfortable travel in a straight line.

[0016] In one embodiment of the invention, the control interface is designed to generate a signal for initiating a speed of the wheelchair upon a user input on the input unit, wherein the initiating speed is in a predefined relation to a distance of a position of the user input from an edge of the first zone.

[0017] In this embodiment, the speed of the wheelchair can depend on how far the position of the user input on the input unit is from the central area, represented by the first zone. The relationship between the speed of the wheelchair and the distance of the position of the user input on the input unit from the first zone can be represented, for example, by a linear curve. However, other curves of this control curve are also conceivable, which advantageously exhibit a continuous and monotonic behavior. For example, a progressive curve such as a parabola can enable particularly sensitive control behavior at low speeds.

[0018] In one embodiment of the invention, the control interface is designed to generate a signal for initiating a direction of travel of the wheelchair upon a user input on the input unit, wherein the initiated direction of travel is in a predefined relationship to a distance of a position of the user input from an edge of the third zone or fourth zone.

[0019] In this embodiment, the direction of travel of the wheelchair can depend on how far the position of the user input on the input unit is from an edge of the zones designed for, for example, straight forward or straight backward travel. The relationship between the direction of travel of the wheelchair and the distance of the position of the user input on the input unit to the third or fourth zone can be represented, for example, by a linear curve. However, other courses of this control curve are also conceivable, which advantageously have a continuous and monotonic behavior. For example, a progressive course such as a parabola can enable particularly sensitive control behavior on large curve radii.

[0020] In one embodiment of the invention, the first zone is arranged centrally on the input unit.

[0021] This zone can be circular or rectangular, for example, and in this embodiment is located in the center of the input unit. This allows user input in any direction relative to the first zone, allowing the wheelchair to be steered forward, backward, left, and right.

[0022] In one embodiment of the invention, the second zone on the input unit comprises two zones arranged to the right and left of the first zone, which zones extend from the first zone to an outer edge of the input unit and have a minimum width.

[0023] According to this embodiment, the second zone can be divided into two parts, comprising an area for counterclockwise turns located to the left of the quiet zone and an area for clockwise turns located to the right of the quiet zone. These zones can be located directly adjacent to the quiet zone and extend to the side edges of the input unit, and can have a minimum width. The position of the user input in this zone can be used to determine, for example, how tight the turn should be and how fast it should be taken.

[0024] Another aspect of the invention includes a wheelchair with a control interface according to one of the embodiments described above.

[0025] In the context of the present invention, however, any self-propelled vehicle controlled by a user via an input unit that processes user inputs in a two-dimensional input field can also be considered a wheelchair. Steering and drive are not necessarily limited to the separate control of two main wheels; any configuration of steered and unsteered wheels can also be controlled using a control interface according to the invention.

[0026] A further aspect of the invention comprises a method for controlling an electrically powered wheelchair, the method comprising the following steps. A first step comprises determining a position of a user input on an input unit of a control interface. A second step comprises calculating a direction of travel and a speed of the wheelchair based on the user input, e.g., by a calculation unit. A third step comprises separately controlling two independent main wheels of the wheelchair according to the calculated direction of travel and speed, e.g., by a control unit.A fourth step comprises generating a first signal upon a user input in a separate, flat first zone on the input unit to cause the wheelchair to come to a standstill, and / or generating a second signal upon a user input in a separate, flat second zone on the input unit to cause the wheelchair to turn on its position.

[0027] The wheelchair is controlled according to a process that can be divided into steps. In the first step, the user input is registered on an input unit. This means that the point on the touchpad or touchscreen the user touches, or the position in which the joystick is held, is measured. In the second step, a calculation unit calculates the desired direction of travel and speed from the registered position according to a pre-stored assignment. In the third step, the driven main wheels of the wheelchair are controlled by a control unit in such a way that their respective rotational speeds cause the wheelchair to travel in the corresponding direction and speed. The fourth step is divided into two sub-steps that do not necessarily have to be carried out consecutively.In the first sub-step, which is executed when a user input is made in the separate first zone of the input unit, the wheelchair is brought to a standstill. In the second sub-step, which is executed when a user input is made in the separate second zone of the input unit, the wheelchair is turned on the spot or with the smallest possible turning radius.

[0028] Further embodiments of the invention are explained below with reference to the following drawings: Fig. 1 shows an embodiment of a control interface according to the invention. Fig. 2 shows a schematic structure of the control interface according to the invention for controlling a wheelchair. Fig. 3 shows a block diagram of the method according to the invention for controlling the wheelchair. Detailed description of the characters

[0029] Fig. 1 shows an embodiment of a control interface 100 according to the invention. The control interface 100, which is advantageously square or rectangular, has an input unit 110 divided into several zones suitable for particular driving situations. A user input in one of these zones leads to the generation of a corresponding control command. Arranged in the center is a first zone 101, which is defined as a rest zone and in which a user input leads to the wheelchair coming to a standstill. Adjacent to this, to the right and left, is a second zone 102, 103, which is designed for turning on the spot. A user input in the right-hand sub-area 102 of the second zone leads to the wheelchair turning on the spot clockwise; a user input in the left-hand sub-area 103 of the second zone leads to the wheelchair turning on the spot counterclockwise.From the first zone 101, pointing rearward in the direction of travel, there is a third zone 104, in which a user input results in the wheelchair moving straight backward. From the first zone 101, pointing forward in the direction of travel, there is a fourth zone 105, in which a user input results in the wheelchair moving straight forward. An area not belonging to the four aforementioned zones, divided into four sub-areas at the four corners of the input unit 110, forms the zone for normal driving 106. Depending on its position, a user input in this zone generates a control command that causes the wheelchair to move forward or backward in a more or less steep curve.

[0030] Fig. 2 shows a schematic structure of a control interface 100 according to the invention for controlling a wheelchair 140. The control interface 100 comprises an input unit 110, a calculation unit 120, and a control unit 130. The input unit 110 determines a user input on the input unit 110. The calculation unit 120 calculates the direction of travel and speed of the wheelchair 140 based on the user input. The control unit 130 separately controls the two independent main wheels of the wheelchair 140 according to the calculated direction of travel and speed.

[0031] Fig.3 shows a block diagram of the method according to the invention for controlling a wheelchair. A first step S1 of determining a position of a user input on the input unit 110 is followed by a second step S2 of calculating a direction of travel and a speed of the wheelchair based on the user input by a calculation unit 120. In a third step S3, two independent main wheels of the wheelchair are separately controlled according to the calculated direction of travel and speed by a control unit 130. This is optionally followed by one of the steps S4a or S4b. In step S4a, upon a user input in the first zone 101, a signal for causing the wheelchair to stop is generated. In step S4b, upon a user input in the second zone 102, 103, a signal for causing the wheelchair to turn on the spot is generated.

Claims

[1] Control interface (100) for controlling an electrically powered wheelchair, comprising an input unit (110) for determining a user input on the control interface, a calculation unit (120) for calculating a direction of travel and a speed of the wheelchair on the basis of a user input made via the input unit (110), a control unit (130) designed to separately control two independent main wheels of the wheelchair on the basis of a direction of travel and speed calculated by the calculation unit (120), wherein the input unit has a separate, flat first zone (101) which is designed to generate a signal for causing the wheelchair to come to a standstill upon a user input in this first zone, and / or wherein the input unit has a separate, flat second zone (102, 103) which is designed to generate a signal for causing the wheelchair to turn on the spot upon a user input in this second zone, wherein the input unit (110) has a separate, flat third zone (104) which is designed to generate a signal for causing the wheelchair to reverse upon a user input in this third zone, wherein the input unit (110) has a separate, flat fourth zone (105) which is designed to generate a signal for causing the wheelchair to move forward when a user input is made in this fourth zone, wherein the third zone (104) and / or the fourth zone (105) on the input unit (110) each have a minimum width, wherein a change in the position of the user input within the minimum width of these zones does not result in a change in the direction of travel of the wheelchair. [2] Control interface (100) according to claim 1, wherein the control interface is designed to generate a signal for initiating a speed of the wheelchair upon a user input on the input unit (110), wherein the initiating speed is in a predefined relation to a distance of a position of the user input from an edge of the first zone (101). [3] Control interface (100) according to claim 1 or 2, wherein the control interface is designed to generate a signal for initiating a direction of travel of the wheelchair upon a user input on the input unit (110), wherein the initiated direction of travel is in a predefined relation to a distance of a position of the user input from an edge of the third zone (104) or fourth zone (105). [4] Control interface (100) according to one of the preceding claims, wherein the first zone (101) is arranged centrally on the input unit (110). [5] Control interface (100) according to one of the preceding claims, wherein the second zone (102, 103) comprises two zones arranged to the right and left of the first zone (101), which zones extend from the first zone to an outer edge of the input unit (110) and have a minimum width. [6] Wheelchair with a control interface (100) according to one of the preceding claims. [7] A method for controlling an electrically powered wheelchair, the method comprising the steps of - Controlling the electrically powered wheelchair by means of a control interface (100) according to one of claims 1 to 5, - determining a position of a user input on an input unit (110) of a control interface (100) (S1), - Calculating a direction of travel and a speed of the wheelchair based on the user input (S2), - separate control of two independent main wheels of the wheelchair according to the calculated direction and speed (S3), - generating a first signal upon user input in a separate, flat first zone (101) on the input unit to cause the wheelchair (S4a) to come to a standstill, and / or - generating a second signal upon user input in a separate, flat second zone (102, 103) on the input unit to cause the wheelchair to turn on the spot (S4b).

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