WO2012172134A1

WO2012172134A1 - Driving assist device

Info

Publication number: WO2012172134A1
Application number: PCT/ES2012/000168
Authority: WO
Inventors: Fernando VIDAL VERDU; Andrés TRUJILLO LEON; Rafael NAVAS GONZALES; José Antonio HIDALGO LOPEZ; Julián CASTELLANOS RAMOS; Oscar Oballe Peinado; José Antonio SANCHES DURAN
Original assignee: Universidad De Malaga
Priority date: 2011-06-17
Filing date: 2012-06-05
Publication date: 2012-12-20
Also published as: ES2394994B2; ES2394994A1; ES2394994A9

Abstract

The invention relates to a driving assist device for vehicles, forming a man/machine interface for facilitating the driving of motor-driven vehicles (3), such as wheelchairs, electric cars, etc., said device essentially comprising a touch sensor (1) intended to be installed in the handle or handlebar (2) of the vehicle and means for processing and conditioning the information provided by the sensor (1) such that the user's intentions are converted into instructions for the motor system of the vehicle.

Description

ASSISTED DRIVING DEVICE

DESCRIPTION

Object of the invention.

The present invention relates to an assisted driving device, and more specifically to a new man-machine interface for facilitating the driving of vehicles powered by engines such as wheelchairs, electric cars, etc.

More specifically, the object of the invention is to help people who, due to their advanced age or an illness, need to use a wheelchair, or those who, without suffering any kind of physical disability, are obliged to handle these chairs very regularly. as assistants of disabled people.

On the other hand, it also constitutes an aid for all those people who due to their age or physical condition are forced to drive any type of vehicle, such as for example the case of a shopping cart or similar, making their driving easier and handling

Background of the invention

In the state of the art there are many devices that serve as an interface to man to drive vehicles, these being commonly flyers or levers, or lately the so-called "j oysticks", which can even be handled with different parts of the body. These devices, while still very useful in most cases, have some drawbacks. One of these disadvantages is that it is constituted by moving parts, which implies a greater vulnerability to wear and damage, as well as a lower energy efficiency.

Another drawback is generally that of the low naturalness of its use, which makes them unintuitive and difficult to use, which reduces their usability, especially in the case in which the person who manages them is elderly or disabled .

In addition, in the particular case of electric wheelchairs, these have two motors that propel the two main wheels independently to allow turning maneuvers including very tight turns, for which they are usually directed with a joystick operated by hand. However, there are cases in which this is not possible. For example, in people who. have suffered an injury to the upper part of the spinal cord, have certain diseases of the nervous system, who are intellectual disabled, or blind. To this group you can also add very old people and / or with Alzheimer's. Some studies reveal that 40% of patients who use an electric wheelchair find their driving difficult, and between 5 and 9% need assistance from another person. In some of these cases, autonomy can be facilitated with the so-called smart chairs, which incorporate sensors and algorithms used in the field of mobile robotics that solve these problems. However, in many other cases this is not possible and an assistant needs to carry the chair.

In these cases, the chairs usually have the so-called "joysticks", which are incorporated into the rear handlebar of the chair. However, as already mentioned, these man-machine interfaces are not always the most appropriate tool.

For this reason, some chairs incorporate an alternative interface such as touch screens. In them the user touches the screen, similar to the one many smart devices have today, to direct the chair or indicate its destination. However, this solution often suffers the above described disadvantage of unnaturalness in handling and thus improper human interaction with the machine, which ^is' to the detriment of the final assembly usability.

There are also other solutions known in the market in which a device adapts to a conventional wheelchair so that a wheel coupled to an electric motor helps in the impulse of the chair when so decided by the assistant, who controls the speed of that wheel with a proportional control coupled to the left side of the handlebar. In this case, however, you do not assist in turning maneuvers, as a chair does electric wheels or the aforementioned systems, in which there are two wheels with independent motors that allow to assist in turning maneuvers by regulating the speed of each motor separately.

Finally, by way of example, the translation of ■ European Patent in Spain n ° 2198972 T3, entitled "Control system of electric motors of propulsion of a transport car" or the publication can be cited as background of the prior art. "Haptic control for the interactive behavior operated shopping trolley InBOT", Proceedings of the New Frontiers in Human-Robot Interaction Symposium at the Artificial Intelligence and Simulation of Behavior (AISB) 2009 Convention, by the authors Góller,. , Kerscher, T., Ziegenmeyer, M., Rónnau, A., Zóllner, J.M. and Dillmann, R.

In these cases it is proposed that the user take a handlebar or handle with his hands and steer the vehicle as he would if he propelled it. However, they do not use a really direct interface between man-machine, but the force exerted on the handlebar is moved by the handle to other points where force and / or torque sensors are placed. However, this way of acting can give rise to problems arising from the deformation of the elastic bands or the means used to transmit the user's instructions. In addition, the deformation of these zones can have a complex behavior over time as a result of a complex dynamic of the whole and the reading of the sensor placed in the bands or joints They would reflect this elastic, making the control (from the sensor readings) more complex.

Description of the invention

The assisted driving device of the present invention which aims to introduce a new man-machine interface for driving vehicles - such as wheelchairs and electric cars solves the drawbacks of the state of the art indicated above because it provides a very intuitive driving and therefore it needs little or no training, thus its usability is also very high.

On the other hand, having no moving parts, wear is very small, that is, the device is robust. It is also indicated for people with reduced mobility who cannot operate another interface for this reason.

For this, the assisted driving device for vehicles of the present invention comprises at least one touch sensor which has means not only to give information of the presence of pressure at a point on its surface, but also of the place where it is produced and of the magnitude of that pressure, that is, it provides a pressure distribution map on its surface or tactile image.

More specifically, the touch sensor usually gives a tactile image in the same way that a television monitor ^■ provides a visual image, where the touchscreen is equivalent to the pixel and where said touch sensor can have a greater or lesser spatial resolution, depending on the amount of information you want to obtain. In addition, the touch sensor is an information input device, that is, if an object is placed on the touch sensor, a pressure map is obtained that tells where there is contact and with what force. This is very important since it differentiates these touch sensors from the so-called touch screens, which say where there is contact but not what is the contact force at those points.

Thus, thanks to this feature, the touch sensor of the invention provides a series of advantages over the state of the art, such as, among others, the following: - The handle or handlebar of the vehicle in which the device of the device is installed. The invention does not have to move or transmit any effort to another point where sensors are placed, therefore the design is simpler and less critical in terms of the assembly and mechanics of the handlebars.

- The device detects in real time and at all times whether or not there is contact with the user, which is very useful for the vehicle stop and lock function, since this will happen only if the user releases the handle or handlebar, which will also save energy and reduce the wear of the chair's locking elements, in addition to allowing a smoother ride.

- The touch sensor also has the additional advantage that it can be used as an interface or information input panel such as modes of use, user, etc. - The touch sensor will provide large amounts of information through the captured touch image, and that can be used to improve the quality of driving, such as the location of the grip points, the size of the user's hands, etc. .

Thus, when the user interacts with the handlebar or handle of the chair or car, it exerts a pressure pattern that will depend on its intention: accelerate, brake or turn left or right, the electronics included in the device of the invention performs the conditioning and processing of the information received, identifying the intention of the user based on the pattern of force on the handlebar or handle using an algorithm developed for that purpose. The results obtained from the algorithm are translated into input signals of the control electronics that are equivalent to those that would arrive if the device were of the "joystick" type.

Description of the figures.

To complement the description that is being made and in order to facilitate the understanding of the characteristics of the invention, a set of drawings is attached to the present specification in which, for illustrative and non-limiting purposes, the following has been represented: Figure 1.- Shows a schematic view of the calculation of the center of mass at one point. Figures 2a to 2d.- It shows in a schematic way the displacement of the center of mass of the left hands (left frame) and right (right frame) when they make a vehicle movement forward, backward, turn to the right and left turn respectively.

Figure 3.- Shows a schematic view of the position, shape and component parts of the device of the invention.

Figure 4.- Shows a schematic view of a possible example of practical embodiment of the device of the invention.

Preferred embodiment.

As can be seen in Figures 1 to 4, a possible practical embodiment of the assisted driving device of the invention comprises a touch sensor (1) located on the handle or handlebar (2) of the chair, or car or vehicle (3 ) whose conduction is desired to assist, wherein said touch sensor (1) in turn comprises a set of individual sensors of suitable configuration, or according to another possible one, using any of the known technologies: piezoresistive, capacitive, optical, etc. . A possible practical embodiment of the invention at low cost would be to cover a set of electrodes implemented in a printed circuit board with a rubber or polymer with piezoresistive properties.

As already it mentioned, when the user interacts with the handle or handle (2) of the chair or carriage (3) exerts a pressure pattern that depends on the intent of this: accelerate, brake or turn left or ^■ right. Then, the electronics included in the device of the invention carry out the conditioning and processing of the information received, identifying the intention of the user based on the force pattern on the handle or handlebar (2) by means of an algorithm, the results of which are translated into input voltages of the driving assistance control electronics.

A possible example of processing of the tactile image and of the pressure pattern exerted by the user is the use of the mass center of the tactile image of a touch sensor (1), where, in particular, said center of mass is defined Touch image of a touch sensor NxM touch such as:

∑ ^ i∑y = i ^χ 'f (¿x> y)

∑ Li∑ ^" ty- ^ f. ^ Ty)

x V

Where is the row number, 'the column number, the value of the force at the coordinates indicated by

Í (c e

^ ^' , and the point ^ ^{x> r} ' is the center of mass. As an example, Figure 1 shows the matrix resulting from the reading of a touch sensor and its mass center calculated for the point that appears in the upper left corner. Experimentally it is observed that the center of mass of the tactile images obtained by two tactile sensors placed on the left side and the right side of the handle or handlebar (2) are displaced when the user tries to make a maneuver, and that these displacements can be interpreted .

For example, in figures 2a to 2d the displacement of the center of mass can be seen, where the touch sensor (1) has been divided in two, to the left for the left hand and to the right for the right hand, when they perform a movement of the vehicle forward, backward, right turn and left turn respectively. According to a possible general application, all the information of the tactile image, for example the size of the hand, could be used to adapt the driving. If only the center of mass is used, it is possible to take advantage of the knowledge of the two coordinates of the same or even one in the simplest case. In this simpler case, only the coordinate can be used and, as has been done in the embodiment Preferred detailed below. Note that the touch sensor (1) can then be constructed with a smaller number of tactels and these will have the shape of an elongated strip along the handlebar as shown in the embodiment example of Figure 3.

Taking this into account, and according to a possible practical embodiment of the invention, a number of six tactics per touch sensor (1) could be sufficient, using two sub-matrices of the touch sensor (1) or two touch sensors (1), one for Each side of the handlebar.

The x coordinate of the centers of mass of the two sub-matrices can be used for example to know the separation between the hands and calculate the moment of force applied. The touch sensor (1) can also be configured for different uses and users if it is used as a data entry panel, that is, by pressing on areas that are identified with buttons (which can be a single touchscreen) or by using the path from the mass center to implement a gestural interface.

Finally, a possible electronic implementation of the device of the invention is shown in Figure 3, where, as can be seen, the touch sensors (1) are placed on the handle or handlebar (2) of the chair or carriage (3) .

Said tactile sensors (1) are of the piezoresistive type and are implemented in two tactile sensors (1 ') and (1'') (or in two sub-matrices of the same sensor touch (1) not shown), one for each hand, with 6 force sensors (8) elongated.

Thus, the signal from the force sensors (8) is conditioned, for example by a circuit based on an Operational Amplifier (4). The output signals of this circuit for each force sensor enter an analog multiplexer (5) and whose output is connected to the input of the Analog-Digital converter of a microcontroller (6).

Said multiplexer (5) is not necessary if the microcontroller (6) has a sufficient number of Analog / Digital input channels. On the contrary, if a tactile sensor (1) with a greater number of tactics (force sensors) is implemented then some additional circuitry and interference reduction strategies may be necessary.

In this way, the microcontroller (6) calculates the center of mass of each force sensor and obtains a coordinate and of each sensor (for this implementation only one coordinate can be obtained and because the tactile sensors (1) are matrices of one dimension To generate the signals for the control electronics

(7), the coordinate and its center of mass are taken as output of both tactile sensors (1 ', 1''). The x and y components of the forward or reverse speed are then obtained as a linear function of the sum of the outputs of both touch sensors (1 ', 1'') and the speed Turn left or right as a linear function of the subtraction of the outputs of both touch sensors (1 ', 1'').

Finally, the output values of the previous algorithm are delivered to the control electronics (7) by the microcontroller (6) for example through a pulse width modulated signal or with a Digital-Analog converter that gives a voltage value proportional to that of the algorithm output and within the input range of the control electronics of the chair or car motors.

Claims

1.- Assisted driving device for vehicles (3) intended to be installed on the handle or handlebar (2) of said vehicles (3) characterized in that it comprises:

at least one touch sensor (1) that provides information on the presence of pressure, the place where it is produced and the magnitude of that pressure at a point on its surface;

- means for conditioning and processing the information received by the touch sensor (1) to identify the intention of the user based on a pattern of force on the handle or handlebar (2) obtained by applying an algorithm; Y

- means to convert the results obtained from the algorithm into input signals to a control electronics.

2. Assisted driving device according to claim 1, characterized in that the processing of the tactile image of the pressure pattern exerted by the user on the touch sensor (1) is based on the use of the center of mass of said tactile image where said center of mass of the tactile image of a tactile sensor of NxM tactics is defined as:

t - y ^{* "} C ^) Where is the row number, ¹ the column number, f (xv)

^' the value of the force at the coordinates indicated by

(c e)

xe ^ ^' , and the point ^ *' ^y * is the center of mass.

3. Assisted driving device according to previous claims, characterized in that the tactile sensor (1) in turn comprises a set of individual force sensors (8) or tactels.

4. Assisted driving device according to claim 3, characterized in that each touch sensor (1) in turn comprises two touch sensors (1 ') and (1' ') or two sub-matrices of the same touch sensor (1), intended to be used each for each hand of the user.

5. Assisted driving device according to claim 4, characterized in that each submatrix of the tactile sensor (1) comprises six touch or force sensors (8) in the form of an elongated strip.

6. Assisted driving device according to any of the preceding claims, characterized in that the tactile sensors (1) are of the piezoresistive type.

7. Wheelchair characterized in that in its handle or handlebar (2) incorporates the assisted driving device according to claims 1 to 6.

8.- Electric car characterized in that in its handle or handlebar (2) it incorporates the assisted driving device according to claims 1 to 6.