Field of the invention

The invention relates to a robot having a chassis and a method for controlling the robot.

Object of the invention

An object of the invention is, in particular, to provide a robot with a low propulsion consumption.

Summary of the invention

To this effect, the invention relates a robot comprising an axle housing arranged to receive two wheels and intended to provide steering and propulsion functions of said two wheels, said axle housing being equipped on either side with a motor, each motor having a stator part intended for to be fixed to the axle housing and a rotor part to be rotatably mounted to said wheel, said robot being further arranged to receive control electronics configured to control each of the motors fitted to said axle housing.

Preferably, the axle housing is rotatable around two axes of rotation with respect to a chassis of the robot.

The robot might comprise a stop device for circumscribing in space the displacements of the rear axle.

Preferably, the stop device comprises a plate of rectangular shape defining a main plane and a center of the rectangular shape.

According to an embodiment, the plane orthogonal to the main plane and extending in the longitudinal direction of the plate and passing through the center of the rectangle is a plane of symmetry of the stop device.

Preferably, the plane orthogonal to the main plane and extending in the direction transverse to the longitudinal direction of the plate and passing through the center of the rectangle is a plane of symmetry of the stop device. For example, four screw passages may be formed at the corners of a rectangle centered on the center of the plate.

On an embodiment, four damper passages are formed in the plate at the corners of a rectangle centered on the center of the plate.

Preferably, the stop device has four stops distributed symmetrically with respect to the two planes of symmetry of the stop device.

For example, a stop has a right-angled triangle section whose right angle is disposed at one end of the rectangle forming the plate, one side of the right angle being oriented in the longitudinal direction of the plate, the other side the right angle being directed in the direction of a longitudinal plane perpendicular to the main plane.

Preferably, a vertical section transverse to the longitudinal direction of the plate, the plate is hollowed out on a lower central portion to form a "P" which upper left and right interior angles are provided with fillets.

The invention also relates to a method of controlling a robot comprising an axle housing arranged to receive two wheels and intended to provide steering and propulsion functions of said two wheels, said method comprising to control two motors which are housed in said axle housing, on either side, each motor having a stator part intended for to be fixed to the axle housing and a rotor part to be rotatably mounted to said wheel, said robot being further arranged to receive control electronics configured to control each of the motors fitted to said axle housing.

Figures

Many other features and advantages of the present invention will become apparent from reading the following detailed description, when considered in conjunction with the accompanying drawings, in which:

- Figure 1 is a perspective view of a mowing robot according to the invention;

- Figure 2 is a perspective view of the bottom of the robot of Figure 1;

- Figure 3 is another perspective view of Figure 1;

- Figure 4 is a perspective view of the bottom of the robot of Figure 1;

- Figure 5 is a perspective view of the rear axle of the robot of Figure 1; - Figure 6 is a perspective view of a stop element of the rear axle of Figure 5;

- Figure 7 is a perspective view and a down section of a stop element of Figure 6;

- Figure 8 is a multi-view projection, front, top and bottom, left and right, of the stop element of Figure 6.

- Figure 9 is a perspective view, from the top of the robot of Figure 1.

Detailed description of specific embodiments of the invention

The embodiments described hereinafter being in no way limiting, it is possible in particular to consider variants of the invention comprising only a selection of characteristics described, subsequently isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the state of the art. This selection comprises at least one characteristic, preferably functional without structural details, or with only a part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

The same references are used for identical elements or elements achieving the same function in the different embodiments of the invention that will be described.

Figure 1 is a perspective view of a mowing robot 1 according to the invention.

The mowing robot 1 comprises a chassis 2 which is linked to a front axle housing 100 and to a rear axle housing 200.

The front axle housing 100 is fixed to the chassis 2.

The front axle housing 100 is linked to two front wheels 102 and 104, which are rotating around the front axle housing 3.

At the end of the front axle housing 100 at the wheel 102, the front axle housing 100 comprises a motor 110.

The stator part 112 of the motor is fixed to the front axle housing 100 via a radially external part of a bearing 120 (no shown on the figures). The wheel 102 is fixed to a rotatory part 114 of the motor 110 via the radially internal part of the bearing 120.

At the end of the front axle housing 100 at the wheel 104, the front axle housing 100 comprises a motor 130. The stator part 132 (not shown on the figures) of the motor is fixed to the front axle housing 100 via a radially external part of a bearing 140 (not shown on the figures). The wheel 104 is fixed to a rotatory part 134 (not shown on the figures) of the motor 130 via the radially internal part of the bearing 120.

A cable duct 150 is provided to pass electrical wires, which are not shown in the figures, connected to the motors 110 and 130.

The rear axle housing 200 is linked to two rear wheels 202 and 204, which are rotating around the front axle housing 3.

At the end of the rear axle housing 200 at the wheel 202, the front axle housing 200 comprises a motor 210.

The stator part 212 (not shown on the figures) of the motor is fixed to the rear axle housing 200 via a radially external part of a bearing 220 (not shown on the figures). The wheel 202 is fixed to a rotatory part 214 (not shown on the figures) of the motor 210 via the radially internal part of the bearing 220.

At the end of the rear axle housing 200 at the wheel 204, the front axle housing 100 comprises a motor 230.

The stator part 232 (not shown on the figures) of the motor is fixed to the front axle housing 200 via a radially external part of a bearing 240 (no shown on the figures). The wheel 204 is fixed to a rotatory part 234 (not shown on the figures) of the motor 230 via the radially internal part of the bearing 220.

A cable duct 250 is provided to pass electrical wires connected to the motors 210 and 230 which are not shown in the figures.

The rear axle housing 200 is pivotally mounted on a steering pivot 400 around a horizontal axis, which is perpendicular to the longitudinal axis of the rear axle housing 200.

The steering pivot 400 is pivotally mounted on a blocking device 500 around a vertical axis.

The blocking device 500 is adapted to circumscribe in space the displacements of the rear axle housing 200. The blocking device 500 comprises four damping devices 550, as rubber. The damping devices help to ensure long life for the blocking device. The blocking device 500 device is fixed on the chassis 2.

Therefore, the chassis 2 can rotate around the forward driving direction and around the vertical direction.

As it might better seen on Figure 9, The steering pivot 400 is extended by a tube 600 opening into the chassis 2. The tube 600 forms

A-cable duct 600 «-provided to pass electrical wires, which are not shown in the figures, connected to the motors 210 and 230.

The tube 600 is rotationally integral with a flag 602.

The chassis 2 is further provided with a sensor 604 for the angular position of the flag 602. In the example shown in Figure 9, the sensor 604 of the angular position of the flag 602 is a rangefinder.

The rangefinder 604 emits an infrared wave that is reflected on the flag602, linked to the axis of the rear axle. The value received by the rangefinder changes according to the distance of the reflective object which is the flag. When the rear axle moves angularly around the vertical axis, the distance of the flag from the rangefinder changes. We can therefore measure the angular position of the rear train.

Therefore, the motors 210, 230, are controlled by a controller 300 which is fixed to the chassis 2.

The data provided by the sensor of the angular position of the flag 602 are sent to the controller 300.

Therefore, the angular position of the free rear train is known and the robot might be driven.

The controller 300 controls the motors 210 and 230 in order to change the direction of the mowing robot 1, by pivoting the chassis 2 around the rear axle housing. Therefore, the rear axle housing is a drive and steering axle.

In order to rotate the chassis 2 around the rear axle housing, the controller 300 is configured to control the motors 210 and 230 with two different speed rotations.

The motors 110, 130, are also controlled by the controller 300. In this embodiment, the controller 300 is configured to control the motors 110 and 130 with a same speed rotation. Therefore, the front axle housing is a drive axle but not a steering axle.

The blocking device 500 might be better seen on Figures 6 and 7.

The device 500 comprises a plate 502 of rectangular shape centered around a vertical axis z. The plate has a main plane extending in both directions of its rectangular shape.

The device 500 comprises on one side of the plate 502 with respect to the z axis, a cylinder 504 of annular section. The outer diameter of the annular section is smaller than the width of the plate 502. The inside diameter of the annular section is sufficient to allow a passage of electric cable.

As shown in Figure 7b, the plate 502 has at its center a recess 508 which cooperates with the recess of the cylinder 504 of the annular section. The recess of 508 is of the same diameter as the inside diameter of the annular section.

Four passages 510 are formed at the corners of a rectangle centered on the center of the plate 502. The passages 510 allow the fixing by screw and bolt of the plate 502 on the frame 2.

Four other passages 512 are formed in the plate at the corners of a rectangle centered on the center of the plate 502. The passages 512 allow the insertion of the damping device 550 which opens on the opposite side to the cylinder 504 with respect to the z axis.

The plane orthogonal to the main plane and extending in the longitudinal direction of the plate and passing through the middle of the width of the rectangle forming the plate is a plane of symmetry of the device 500.

The plane orthogonal to the main plane and extending in the direction transverse to the longitudinal direction of the plate and passing through the middle of the length of the rectangle forming the plate is a plane of symmetry of the device 500.

On the side of the plate 502 opposite the cylinder 504 with respect to the axis z, the device 500 has four stops 506 distributed symmetrically with respect to the two planes of symmetry of the device 500. More specifically, a stop 506 has a right-angled triangle section whose right angle is disposed at one end of the rectangle forming the plate 502, one side of the right angle being oriented in the longitudinal direction of the plate, the other side the right angle being directed in the direction of the axis z opposite to the cylinder 504. The stop has an extension of the right triangle in the direction of the width of the rectangle forming the plate 502.

Figure 8 shows the device 500 in a multi-view projection, front, top and bottom, left and right, according to the US third-angle projection.

In a vertical section transverse to the longitudinal direction of the plate 502, the plate 502 is hollowed out on a lower central portion to form a "P" which upper left and right interior angles are provided with fillets.

Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In addition, the various features, forms, variants and embodiments of the invention can be combined with one another in various combinations insofar as they are not incompatible or exclusive of one another. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.