WO2017064668A1

WO2017064668A1 - Device to automate an electric wheelchair

Info

Publication number: WO2017064668A1
Application number: PCT/IB2016/056177
Authority: WO
Inventors: Victor L. CARMONA; Pablo F. DIEZ; Eric L. LEBER; Vicente A. MUT; Enrique M. AVILA PERONA; Gustavo ENSINCK
Original assignee: Consejo Nacional De Investigaciones Cientificas Y Tecnicas (Conicet); Universidad Nacional De San Juan; Inis Biotech Llc
Priority date: 2015-10-14
Filing date: 2016-10-14
Publication date: 2017-04-20

Abstract

An electronic device to automate an electric wheelchair, where the wheelchair is capable of accepting commands coming from a computer and moving according to these commands. The device of the invention emulates the commands sent by a wheelchair joystick. Thus, a commercial wheelchair with joystick can be driven by speed and direction digital commands coming from a computer. On the computer, Human-Machine Interfaces can be implemented, useful to help people with disabilities who cannot command a wheelchair by means of a joystick but are able to take decisions regarding the direction and speed they want to apply to the chair. The device comprises at least four modules, a main module controlled by a microcontroller, a digital/analogic conversion module, a module for communication between a computer and said microcontroller, and a module responsible of actuating joystick switches.

Description

DEVICE TO AUTOMATE AN ELECTRIC WHEELCHAIR

Field of the Invention

The present invention relates to a device to automate an electric wheelchair.

Background of the Invention

Mobility is inherent to the human being; from infancy a child begins to move himself and explore his environment. However when mobility is restricted, using an electric wheelchair may allow one to participate in tasks and routines that make up everyday life, which would otherwise not be possible. In a person with reduced mobility, moving in a motor wheelchair is comparable to walking, as it facilitates equal access to: choosing and making decisions, accessing information, participating in education, employment, leisure and family life. Until a few years ago, a person who could not manually propel a wheelchair and who could not drive an electric wheelchair joystick was forced to be led by another person.

Individuals with severe motor disabilities are prevented from moving by themselves. Quadriplegic individuals represent extreme cases in which moving their arms or their legs is not possible. Occasionally, their language brain center is also affected and therefore they cannot keep fluid verbal communication with other individuals in their surroundings. There are many causes for these disabilities, like pathologies such as Cervical Injuries due to severe trauma, Multiple Sclerosis, Amyotrophic Lateral Sclerosis, Muscle Dystrophies, Brain Palsy, and Stroke.

Unfortunately, people suffering from severe motor disability usually have to remain prostrate the rest of their lives, a condition that becomes aggravated in cases of loss of speech. Therefore, individuals with severe motor disabilities are in need of innovative assistance technologies in order to autonomously move and communicate. Among the so called Assistance Systems there are different devices for allowing people to recover their impaired or loss abilities, e.g. assistance robotic systems, like robotic wheelchairs and tele-presence systems; and communication systems, which allow individuals asking for help, expressing emotions and talking with other people.

The objective for developing an automated wheelchair is essentially to improve the quality of life of people suffering from quadriplegia. For that purpose the available technology should be adapted in order to reduce costs of materials to be used, seeking for alternatives allowing such reduction, like control systems by which expenses can be reduced by using the lesser possible amount of electronic components, also decreasing energy consumption, and replacing expensive sensors by others that produce similar results after slight modification, but at a much lower cost. The present invention is based on a low cost technology when compared to available commercial equipment, so as to give more people a chance to recover mobility and improve their quality of life.

For people with severe disability it is necessary to use Human-Machine Interfaces, i.e. software and/or hardware necessary for a person, who is incapable of commanding a wheelchair by means of a joystick, to be able by means of the interface. Currently, in general these interfaces are implemented in a computer or similar device mounted on the wheelchair. However, it is necessary to develop further control electronics in order to command a wheelchair, resulting in an expensive customized development, time consuming and difficult to generalize to other users.

There are no commercially available automated wheelchairs, since the existing models are laboratory prototypes used for experimentation. These models, in general, employ an electric wheelchair but disregard all electronics for the wheelchair control. Considering the current development of Human-Machine interfaces, their commercialization can be expected soon. No doubt, there will be a need for automated wheelchairs produced with costs similar to electric wheelchairs commanded by joysticks and easy implementation. Brief Description of the Invention

It is thus an object of the present invention providing an electronic device to automate a wheelchair without intervening the communication protocol between the controller and the power module usually present in an electric wheelchair. This means that the wheelchair is capable of accepting commands coming from a computer and moving according to said commands. The device of the invention emulates the commands sent by a joystick to a wheelchair. Thus, a commercial wheelchair with joystick can accept speed digital commands coming from a computer. On the computer, Human-Machine Interfaces can be implemented, useful to help people with disabilities who cannot command a wheelchair by means of a joystick but are able to take decisions regarding the direction and speed they want to apply to the chair.

It is also an object of the present invention providing a device that allows transforming an electric wheelchair into an automated wheelchair, just by attaching (installing) the device of the invention.

It is a further object of the invention providing a device for an individual with a progressive condition who already has an electric wheelchair, which device can transform at a low cost their wheelchair compared to developing a new wheelchair or purchasing a new automated one.

It is therefore an object of the invention providing a device to automate an electric wheelchair, where this device allows emulating the operation of joysticks of electric wheelchairs, wherein the device comprises at least four modules, a main module controlled by a microcontroller, a digital/analogic conversion module, a module for communication between a computer and said microcontroller, and a module in charge of actuating on joystick switches for functions in addition to movement.

Brief Description of the Drawings

For a better understanding of the invention, a preferred embodiment, by way of example, is illustrated in the following figures:

Figure 1 shows a flow chart illustrating the operation of the device of the present invention.

Figure 2 shows a flow chart of UART interruption.

Figure 3 shows a flow chart of the main software run on the device of the present invention.

Figure 4 shows a photograph of the device of the present invention when applied to a wheelchair.

Figure 5 shows a photograph of a selector switch for switching between the joystick command for normal operation and the computer command when functioning as an automated wheelchair).

Figure 6 shows a schematic chart illustrating the access point to the device system of the present invention.

Detailed Description of the Invention

The present invention is based on the emulation of the commands sent by the joystick to the power module. To this end, a voltage equivalent to that provided by the integrated circuit that measures the shifting of the grip portion should be generated. For simulating said shifting and producing the corresponding variable voltage values, according to the present invention the voltage values are generated by means of a microcontrolled system. The microcontroller circuit board operation is illustrated in Fig. 1. In said figure it can be appreciated that the microcontroller has to establish a protocol for communication with the computer. On this computer it is implemented the Man- Machine Interface between a disabled individual and the wheelchair. Therefore, an USB (Universal Serial Bus) is preferred, due to it being the most ordinarily used in modern computers. For implementing this connection, an integrated circuit is used for translating the microcontroller UART series protocol into the USB protocol.

Once it has received a speed command from the computer, the microcontroller must convert it into the commands that the joystick would send to generate the desired speed and direction. In this way, digital commands are generated and converted into analogic voltage values by means of a digital/analogic (D/A) converter. This D/A converter may be external or be included within the microcontroller itself. On the other hand, the user can optionally command the wheelchair by means of the joystick command. To that end, it is provided a switch (Fig. 5) that can be manually controlled but could be also controlled by the microcontroller.

The wheelchair to which the device of the invention can be applied to, generally are provided with rear and front lights, turn and emergency lights and a horn, all of which are controlled by a factory controller. Therefore, in order to keep the same characteristics, the device of the present invention is also provided with digitally controlled analogic switches so as to emulate all of the commands of the wheelchair factory controller.

Fig. 2 shows a flow chart illustrating the process carried out for UART port interruption. Data are received as a character string as follows:

Joystick horizontal movement: "H [value from 0 to 255, defining the voltage supplied to the joystick] F". - Joystick vertical movement: "V [value from 0 to 255, defining the voltage supplied to the joystick] F".

- Activated key: "T [value from 1 to 8, defining the activated key] F"

As can be observed, the first character of the command sent by the computer represents the course of action to be followed. The letter F corresponds to the command finalization. The remaining characters define the value to be implemented, between 1 and 255 (8 bits). It is possible to distinguish the key to be activated and for joystick movements it is possible to select the value to be introduced into the D/A converter port so as to generate a voltage proportional to said value. Each time a command is received from the computer, this software part is accessed, starting to save characters in a string until an "F" character is received indicating the end of the command. Afterwards, the command is saved so as to process it on the main software. Besides, before returning from the interruption, an interruption flag is activated.

Fig. 3 shows the flow chart of the microcontroller main software. Each time a command arrives, the interruption flag is activated and the system is able to process the received command. It can be appreciated in the flow chart that the action executed by the microcontroller will depend on the command nature. If the action is a joystick movement, it will introduce into the D/A converter port the value of the received command. On the contrary, for activating a key, the microcontroller will simply activate the control signal of the corresponding switch. It should be noted that in Fig. 4, the maximum and minimum values of the commands are limited between 57 and 200, since these values represent the maximum voltages supported by the factory wheelchair controller.

Fig. 5 shows the device housing and a changeover switch. This way, a user can switch between commanding the wheelchair with the joystick or with the computer, just pressing the changeover switch. It should be noted that it is possible to add sensors to the device in order to measure surrounding variables, mainly to measure distances and avoid collisions. Said sensors may be of different kinds, such as laser or ultrasound sensors. Measures taken by the sensors may be used in the microcontroller to run control algorithms or be transferred to the computer through a USB port with the same purpose.

Fig. 6 shows a scheme of the access point to the control system (joystick) of the wheelchair. Thereby, it is possible to keep total control of all of the controller device functions of the wheelchair, i.e. all turn on/off buttons, light commands and other functions of the chair system besides the wheelchair movement. This approach allows accessing the system without the need of introducing modifications to the structure of communication with the power module.

Those skilled in the art will recognize or be able to ascertain, using only routine experimentation, many equivalents to the specific embodiments and examples described herein. Such equivalents are intended to be within the scope of the present invention and encompassed by the appended claims.

Claims

1. A device to automate an electric wheelchair, where the device allows emulating the operation of joysticks of wheelchairs, wherein the device comprises at least four modules, a main module controlled by a microcontroller, a digital/analogic conversion module, a module for communication between a computer and said microcontroller, and a module responsible of actuating joystick switches.

2. The device according to claim 1, wherein said microcontroller performs the whole system control, further interpreting the commands received from the computer and processing them to be subsequently used by the digital/analogous converter or by analogic keys.

3. The device according to claim 1, wherein said digital/analogic conversion module is configured to receive a series of digital codes and create an analogic voltage according to the received information.

4. The device according to claim 1, wherein the module for communication between the computer and the microcontroller comprises an integrated circuit consisting of a serial interface converter USB-UART.

5. The device according to claim 1, wherein the module responsible of actuating on joysticks switches is commanded by a plurality of integrated circuits.

6. The device according to claim 5, wherein each integrated circuit is provided with bilateral switches for handling analogic signals that are digitally controlled by control terminals.

7. The device according to claim 1, wherein said device allows for the connection to different kinds of sensors.

8. The device according to claim 1, wherein said device allows commanding an electrical mobile device without affecting communication and/or structure between joystick/controller, wherein an analogic switch is interposed that is capable of switching between manual command and computerized command, wherein the switch can be commanded manually or by means of an electronic system.