WO2006051105A1

WO2006051105A1 - Cleaning machine and steering device for such a cleaning machine.

Info

Publication number: WO2006051105A1
Application number: PCT/EP2005/055926
Authority: WO
Inventors: Francesco Battistella
Original assignee: AMER SpA
Current assignee: AMER SpA
Priority date: 2004-11-12
Filing date: 2005-11-11
Publication date: 2006-05-18
Anticipated expiration: 2007-05-12
Also published as: ITVI20040265A1

Abstract

Cleaning machine (1) of the type comprising: a chassis (2) complete with wheels (3, 4, 5); driving means (6) including a geared motor (21) associated with one of the wheels (3, 4, 5); steering means (7) comprising a geared motor (30) for steering one of the wheels (3, 4, 5) and a central processing unit (9) governing the steering action; means (18) for monitoring the angular position of the wheel (5) associated with the steering motor (30); means (17) for monitoring the travel speed of the machine (1); control means (8) governing the driving means (6) and the steering means (7). The central processing unit (9) consists of a microcontroller (10) with a programmable memory element (11) containing one or more programmed functions suitable for correlating the electrical values coming from the control means (8) and from the means (17) and (18) for monitoring the speed of the machine and the angular position of the wheel, in order to adjust the power supply to the steering geared motor (30).

Description

Description of the Letters Patent entitled: "CLEANING MACHINE AND STEERING DEVICE FOR SUCH A CLEANING MACHINE". On behalf of the Company AMER S.P.A. - Via Maestri del Lavoro, 1 (Localita Tommasoni) - 36078 VALDAGNO (Vl). DESCRIPTION

The present invention relates to a cleaning machine particularly suitable for the industrial cleaning sector.

The invention also concerns a steering device particularly suitable for installation in such a cleaning machine. The cleaning machines available on the market are known to use only mechanical or servo-assisted rack or chain-drive steering systems. Machines of this type can be used in large, unobstructed spaces, such as outdoor hardstandings or airports, or in more limited spaces such as supermarkets, warehouses and offices, where the cleaning machine is required to respond promptly to the user's controls as well as to ensure an excellent manoeuvring precision.

Being fitted with mechanical or servo-assisted steering systems, the known cleaning machines are difficult to use in limited spaces, where they must steer around obstacles. In particular, a first drawback of machines belonging to the known art is that any attempt to make an abrupt change of direction at medium or high speed can make the machine overturn.

Another drawback is intrinsic in the conditions of use of these machines. The surfaces on which they are used are generally wet and slippery and any abrupt steering manoeuvre is liable to give rise to understeering.

When there is an operator on board, another, not necessarily last drawback is due to the fact that the bulky nature of the steering system makes it necessary to equip the cleaning machines currently used with a large fairing that restricts the user's visual field, particularly interfering with the use of such machines in environments that contain numerous obstacles.

To avoid the risk of toppling and understeering, some cleaning machines are fitted with speed limiting devices which overcome these problems, but also reduce the average speed of the machine and consequently also its working efficiency when it is operated in large spaces where there are no obstructions. The object of the present invention is to overcome all the above-mentioned drawbacks.

In particular, a first object of the invention is to provide a cleaning machine complete with an electronic steering control so as to avoid any problems relating to toppling and understeering. Another, not necessarily last object of the invention is to provide a machine that, compared to equivalent machines of the known art, ensures an excellent visibility when in use.

The aforementioned objects are achieved by a cleaning machine of the type comprising: - a chassis fitted with wheels;

- driving means consisting of at least one geared motor associated with at least one of said wheels;

- steering means consisting of at least one steering geared motor associated with at least one of said wheels and with a central processing unit for governing said steering action;

- means for detecting the angular position of said wheel associated with said steering motor;

- means for monitoring the speed of said machine;

- means for controlling said driving means and said steering means at the disposal of the operator, characterized in that said central processing unit includes at least one microcontroller with at least one programmable memory element containing one or more programmed functions suitable for correlating the electrical values coming from said control means and from said means for monitoring said speed and said angular position, and thereby modifying the power supply of said steering geared motor.

According to the preferred embodiment of the invention, the cleaning machine is fitted with two rear wheels and one front wheel, the latter being associated with the steering means and the driving means. The electric signals that the programmed functions correlate consist in a voltage value proportional to the speed of the machine, a digital signal proportional to the angular position of the front wheel and a voltage value proportional to the position of the control means. The preferred embodiment of the cleaning machine of the invention, wherein there is only one front wheel to which the steering means and driving means are to be associated, advantageously involves greater simplicity of construction of said steering means and of said driving means, with a consequent reduction in their overall dimensions.

The aforesaid objects will be explained in greater detail in the description of preferred embodiments of the invention, with reference to the attached drawings, wherein:

- Figure 1 shows an axonometric view of the cleaning machine subject of the invention;

- Figures 2 and 3 show details of the cleaning machine subject of the invention;

- Figure 4 shows a block diagram of a part of the machine subject of the invention;

- Figure 5 shows a flow chart of the processing function of the steering central processing unit; - Figure 6 shows the curve describing a first programmed function in the central processing unit;

- Figure 7 shows the curve describing a second programmed function in the central processing unit.

The cleaning machine subject of the invention is illustrated in Figure 1 , where it is indicated as a whole by 1 , and where it can be seen that it includes a chassis 2 fitted with two rear wheels 3, 4 and one front wheel 5 with which driving means 6 and steering means 7 are associated.

In a different embodiment, the driving means are associated with the rear wheels. There are also control means 8 at the disposal of the user U for controlling the driving means 6 and the steering means 7.

According to the invention, there is a central processing unit 9 comprising a microcontroller 10 with a programmable memory element 11 that contains two programmed functions for correlating the electrical values coming from the control means 8 and, as shown in Figures 2 and 3, from means 17 for monitoring the speed of the machine 1 and means 18 for monitoring the angular position 18 of the front wheel 5, in order to control the steering action.

As concerns the microcontroller 10, in the preferred embodiment of the invention described herein, it is a microprocessor. As concerns the control means 8, in the preferred embodiment of the invention described herein, these are constituted by a joystick 20, which can move in two directions X, Y, lying substantially at right angles to one another, and the position of the joystick gives two voltage values, a first value relating to its position along a first direction X, and a second value relating to its position along a second direction Y.

The joystick's position along the direction X conventionally represents the steering imposed by the user U and its position along the direction Y represents the required speed. According to a possible variant, the manual control means available to the user may be a steering wheel and a pedal associated with a potentiometer for speed control.

According to another variant, the control means available to the user may be two normal potentiometers. As for the driving means 6 shown in Figure 2, these consist of a driving geared motor 21 , which in the preferred embodiment of the invention is of the direct current, permanent magnet type, is associated with the front wheel 5 of the cleaning machine 1 and is governed by an electronic drive control card 22 of known type. The driving means 6 also include means 17 for monitoring the speed of the machine 1 comprising, in the preferred embodiment, a pair of electric wires 24 that record the voltage of the power supply to the driving geared motor 21 , which is known to be a direct measure of its turning speed. The electronic drive control card 22 receives as an input the second voltage value relating to the speed required by the user by means of the joystick 20 and consequently controls the power supply to the driving geared motor 21 with which it is associated, thus adjusting the latter's turning speed, and therefore varying the travel speed of the cleaning machine 1. According to other variants of the invention, the means for monitoring the speed of the machine may consist of a tachogenerator or a pair of electric wires connected to the electronic card and monitoring the power supply voltage that said card delivers to the geared motor.

As for the steering means 7, as shown in Figure 3, these consist of a steering geared motor 30 associated with the front wheel 5 to change the latter's angular position and consequently steer the machine 1 , and means for monitoring the angular position 18 of said wheel 5 that consist, in the preferred embodiment described herein, of a two-channel encoder 32. Said steering geared motor 30 is of the direct current, permanent magnet type, too.

In different embodiments of the invention, the means for monitoring the angular position of the wheel is constituted by an angular position transducer of known type.

As concerns the central processing unit 9 governing the steering, this consists of an electronic card 12 that, as shown in Figure 4, comprises the following:

- a first block 13 for processing the input signals, consisting of the electrical values coming from the control means 8, from the means 17 for monitoring the speed of the machine 1 and from the means 18 for monitoring the angular position of the front wheel 5;

- a microcontroller 10 associated with a programmable memory 11 ;

- a second block 14 for processing the output signals. The input and output signal processing blocks 13, 14 are not described or illustrated here because they are of known type.

The second block 14 for processing the output signals preferably, but not necessarily, consists of a MOSFET power stage.

In the embodiment of the invention described herein, the input signals consist of the following:

- a first voltage value proportional to the speed of the machine 1 ;

- a digital signal proportional to the angular position of the wheel 5;

- a second voltage value proportional to the position of the control means 8. The microcontroller 10 processes these signals according to a procedure schematically illustrated in the flow chart 37 in Figure 5, which, as mentioned earlier, uses two functions previously saved in the programmable memory 11 , two examples of which are graphically illustrated in Figures 6 and 7. To be more precise, Figure 6 is the graphic representation of a first function for varying the position reference sensitivity of the joystick 20, i.e. for varying the sensitivity of the cleaning machine 1 to different steering angles imposed by the user U.

In the case in point, the electrical voltage values that the joystick 20 can provide are given on the horizontal axis and the percentage of the maximum steering angle with which said voltage value coincides is given on the vertical axis. As shown in the figure, given the exponential trend of the curve, the more this departs from a straight line, the more the steering angle will be attenuated for minor steering actions and accentuated for major steering actions. Figure 7 is the graphic representation of a second function that controls the maximum steering angle, which forms a broken line.

The travel speed of the machine, expressed as a percentage of the maximum speed available to the user U, is given on the horizontal axis, while the maximum allowable steering angle, expressed as a percentage of the maximum steering angle of which the machine 1 is capable, is given on the vertical axis.

As shown in the figure, the full 100% of the available steering angle can be used at low speeds, but as the travel speed increases the maximum allowable steering angle diminishes down to a theoretical value of nil. This function makes it impossible for the user U to change direction more abruptly than the machine 1 can withstand at the various travel speeds.

The output block 14 converts the value of the steering angle required into a control signal to be sent to the steering geared motor 30. In different embodiments of the invention further electrical input values can be used to control the steering action and program other functions aimed to meet the user's particular needs, or to cater for the use of the cleaning machine in particular conditions.

In operational terms, the user U seated in the seat P on the cleaning machine 1 can access the controls and start the machine. Operating the joystick 20 with one hand, the user U can displace the joystick along the direction Y to move the machine 1 and along the direction X to steer it as necessary.

When the user U accelerates, the joystick 20 releases an electric voltage that reaches the electronic drive control card 22, which increases the power supply to the geared motor 21 and consequently also the travel speed of the machine 1.

When the user U wishes to change direction, he/she moves the joystick 20 a given distance along the direction X.

The new value of the electric voltage relating to the position of the joystick 20 along the axis X is sent to the electronic drive control card 22, the first function of which processes this input and consequently adjusts the position reference sensitivity of the joystick 20.

The output from said processing, together with the value of the machine's travel speed, forms the input for the function governing the maximum steering angle, in order to send an electric signal to the steering geared motor 30 and perform the steering action.

As shown in Figure 7, if the steering angle correlated with the travel speed of the cleaning machine is lower than the maximum allowable angle, the machine

1 steers exactly as the user U wishes.

If, however, the steering angle imposed is greater than the maximum allowable angle, the machine 1 steers according to said maximum allowable angle.

In this case, if the user U wishes to obtain a greater steering angle, he/she is obliged to slow down.

Clearly, if the user U accelerates during a steering action beyond the speed limit corresponding to said steering action, the acceleration will induce a consequent reduction in the steering angle of the machine, giving rise to a movement that is at least partially in the shape of a spiral.

In the light of the above considerations, the cleaning machine of the invention clearly achieves all the aforesaid objects.

In particular, the steering means comprising the central processing unit achieve the object of ensuring a controlled steering action and thus avoiding the risk of the machine toppling or any understeering phenomena caused by excessively abrupt steering actions.

Moreover, since mechanical steering means are not used, there is no rack steering system installed on the machine, so that the overall dimensions of the steering system and its fairing are smaller, thus offering a wide all-round view to the user.

Upon implementation changes may be made to the cleaning machine subject of the invention, which may cause further construction variants to be carried out that, should they come within the scope of the following claims, shall all be considered as covered by the present patent even though they are neither illustrated in the drawings nor described herein.

Claims

1 ) Cleaning machine (1 ) of the type consisting of:

- a chassis (2) complete with wheels (3, 4, 5);

- driving means (6) comprising at least one geared motor (21 ) associated with at least one of said wheels (3, 4, 5);

- steering means (7) comprising at least one geared motor (30) for steering the vehicle associated with at least one of said wheels (3, 4, 5) and a central processing unit (9) governing said steering;

- means for monitoring the angular position (18) of said wheel (5) associated with said steering motor (30);

- means (17) for monitoring the travel speed of said machine (1);

- means (8) accessible to the user (U) for controlling said driving means (6) and said steering means (7), characterized in that said central processing unit (9) comprises at least one microcontroller (10) with at least one programmable memory element (11 ) containing one or more programmed functions suitable for correlating the electrical values coming from said control means (8) and from said means (17) and (18) for monitoring the travel speed of the machine and the angular position of said wheel in order to modify the power supply to said steering geared motor (30).

2) Machine (1) according to claim 1), characterized in that said electrical values are:

- a voltage value proportional to the travel speed of said machine (1 );

- a digital signal proportional to said angular position of said wheel (5); - a voltage value proportional to the position of said control means (8).

3) Machine (1) according to claim 1), characterized in that said programmed functions include a first function suitable for adjusting the sensitivity of the steering angle as a function of the position of said control means (8), said first function being expressible by means of an exponential curve.

4) Machine (1 ) according to claim 1 ) or 3), characterized in that said programmed functions include a second function suitable for identifying the maximum allowable steering angle in relation to the travel speed of said machine (1 ), said second function being expressible by means of the equations describing two separate straight lines parallel to the horizontal axis connected by an oblique line.

5) Machine (1) according to claim 1), characterized in that said microcontroller (10) is a microprocessor.

6) Machine (1 ) according to claim 1), characterized in that the motors for said geared motors (21 , 30) are of the direct current, permanent magnet type.

7) Machine (1 ) according to claim 1 ), characterized in that said speed monitoring means (17) consist of a pair of conductors (24) that electrically connect the terminals of said driving geared motor (21 ) to said central processing unit (9).

8) Machine according to claim 1 ), characterized in that said speed monitoring means are in the form of a tachogenerator mechanically associated with said driving geared motor and electrically connected to said central processing unit. 9) Machine according to claim 1), characterized in that said speed monitoring means consist of a pair of conductors that electrically connect a card recording the speed of said driving geared motor to said central processing unit.

10) Machine (1) according to claim 1 ), characterized in that said means (18) for monitoring the angular position of said wheel (5) are in the form of a two-channel encoder (32) mechanically associated with said wheel (5).

11 ) Machine (1) according to claim 1 ), characterized in that said control means (8) are in the form of a joystick (20) with two axes of movement (X, Y) lying at right angles to one another. 12) Machine (1) according to claim 11), characterized in that said two axes of movement (X, Y) include a first axis of movement (Y) governing said driving means (6) and a second axis of movement (X) governing said steering means (7).

13) Machine according to claim 1), characterized in that said control means are in the form of a pair of potentiometers.

14) Machine according to claim 1), characterized in that said control mean consist of a handwheel for governing said steering means and a potentiometer for governing said driving means.

15) Steering device consisting of: - at least one steering geared motor (30) suitable for being associated with at least one of the wheels (3, 4, 5) of a self-propelled machine (1 ); - a central processing unit (9) governing said steering geared motor (30), characterized in that said central processing unit (9) consists of at least one microcontroller (10) with at least one programmable memory element (11 ) containing one or more programmed functions suitable for correlating the electrical values coming from the control means (8) and from the means (17) and (18) for monitoring the travel speed of said machine and the angular position of said wheel (3, 4, 5), so as to adjust the power supply to said steering geared motor (30).