Mobile robot

Abstract

The invention relates to a mobile robot comprising a robot body (1) and at least one robot leg. The aim of the invention is to produce a mobile robot which has a structure that is as simple as possible and is correspondingly robust. According to the invention, this is achieved and that the robot leg comprises an axially movable rod (2) which is pivotally guided on the robot body (1), wherein means (6, 7a, 8a, 9, 10, 11) are provided for axially moving the rod, and means (7b, 8b, 14, 15, 16) are provided for pivoting the rod (2). The robot body (1) location provided for the robot leg is equipped with an opening (22) in which the rod can be moved perpendicularly and at a variable angle relative to the opening (22).

Description

[0001] DESCRIPTION

[0002] Mobile robot

[0003] The invention relates to a mobile robot with a robot body and at least one robot leg.

[0004] In addition to robots with wheels and caterpillar tracks, there are also robots with legs that are used for locomotion, changing height and tilting the robot body.

[0005] From WO 2020 / 169285 A1, a robot leg with at least two joints is known, wherein each joint connects two segments to each other and each joint has a cam, wherein the robot leg also has at least one actuator and a common tendon that connects each cam to each other.

[0006] Such natural-looking robot legs have a relatively complex structure with joints and are therefore expensive to manufacture and prone to repair; moreover, they limit the height to which they can lift the robot body to the length of the segments with the joints extended.

[0007] The present invention is based on the object of creating a mobile robot which significantly extends the area reachable by the robot body and has the simplest possible structure and is accordingly robust.

[0008] This object is achieved according to the invention in a mobile robot according to the preamble in that the robot leg comprises an axially displaceable rod which is pivotally guided on the robot body, wherein means for axially displacing the rod and means for pivoting the rod are provided, wherein at the location of the robot body provided for the robot leg there is an opening in which the rod can be moved vertically and at variable angles relative to the opening.

[0009] The robot leg according to the invention comprises a rod on which the robot body rests, with the lower end of the rod resting on the ground. The rod is either hinged to the outer edge of the robot body for axial movement, or an opening is provided at the location of the robot body intended for the leg, in which the rod can be moved vertically and at variable angles relative to the opening. The devices move the rod relative to the robot body in the longitudinal direction of the rod and change the angle of the rod axis relative to the robot body in two dimensions.

[0010] The devices attached to the robot body thus move the rod three-dimensionally relative to the robot body, thus changing—usually in conjunction with other robot legs—the horizontal and vertical position and inclination of the robot body relative to the ground. The rod can be many times longer than the size of the robot body.

[0011] Such a robot leg has a simple structure and is therefore inexpensive to manufacture and maintain.

[0012] One embodiment of the invention is that the opening of the robot body is continuous.

[0013] Advantageously, the robot body can be moved along the full length of the rod. The robot leg can be arranged inside the robot body. The rod can extend through a continuous opening in the robot body.

[0014] A preferred embodiment of the invention consists in that the rod is a first threaded rod with an external thread and an axially extending groove, wherein the external thread engages in an internal thread which is connected to the robot body in a rotatable and pivotable but not axially displaceable manner, and wherein a pin engaging in the groove is provided to prevent the radial rotation of the rod, that a drive for rotating the internal thread on the rod is provided as a means for axially displacing the rod, and that at least one further drive is provided as a means for pivoting the rod, which is connected directly or indirectly to the first threaded rod.

[0015] By axially moving the threaded rod, the robot leg is moved upwards or downwards (z-axis). The further drive pivots the threaded rod, causing the robot leg to move to the right or left (x-axis) or forwards or backwards (y-axis).

[0016] An advantageous development of the invention consists in providing two drives for pivoting the rod, which are offset from one another and connected directly or indirectly to the first threaded rod. The two drives can be offset diagonally or at right angles to one another. With this configuration, both a right or left movement (x-axis) and a forward or backward movement (y-axis) can occur. The two drives can be configured as servomotors.

[0017] It is also possible to provide a single drive instead of the two drives for pivoting the rod, which pivots the rod in two axes via deflection means.

[0018] It is sufficient that the rod is designed as a threaded rod in some areas.

[0019] The length of these sections determines the vertical adjustability of the robot leg.

[0020] Alternatively, it can be provided that the rod is a preferably rectangular rack, that a drive with a complementary engagement element engaging in the rack is provided as the means for axially displacing the rod, and that at least one further drive is provided as the means for pivoting the rod, which is connected directly or indirectly to the rack.

[0021] An advantageous development of the invention consists in the provision of a control device.

[0022] To enable the robot to utilize the leg structure in a variety of ways, the drives must be equipped with a signal generator to indicate the rotation or other indicator from which the control device can derive the leg position. After the control device has determined the starting positions in an initialization phase, it can move each robot foot to any position within the accessible volume; it can spread the legs to different widths depending on the required stability; it can move the legs around and over high obstacles; it can position the robot body at any height between the ground and the length of the threaded rod.

[0023] An advantageous embodiment consists in the provision of an inclination sensor.

[0024] An inclination sensor is advantageous for control. This allows the robot body to be tilted in a targeted manner and, in particular, it can be kept horizontal at a freely adjustable height, regardless of the terrain.

[0025] The inclination sensor is particularly advantageous for determining whether a robot leg is in contact with the ground. For example, when a robot leg moves toward the ground, ground contact can be determined based on a change in the inclination angle as the robot leg moves.

[0026] The path the robot follows can be very steep and doesn't need to be cleared of obstacles. For example, the robot can climb into and over a hedge. It can operate in shallow water and, if its legs are equipped with plates, even on muddy ground. The robot leaves virtually no trace in the ground along its path.

[0027] The robot is particularly suitable for use in agriculture and horticulture, for example, in vineyards, tea plantations, and rice fields. In addition to control software for locomotion, it requires a device for the specific application task, typically one or two robot arms including the associated control device, a camera and programs for pattern recognition, for example, for identifying specific plants or pests, and finally, a program for orientation and navigation in the terrain. When several robots work simultaneously, their movements relative to each other and their work must be coordinated.

[0028] An embodiment of the invention is explained in more detail below with reference to drawings.

[0029] It shows

[0030] Fig. 1 is a side view of the section of a mobile robot according to the invention, which is relevant for a robot leg,

[0031] Fig. 2 a plan view from the bottom of the mobile robot according to Fig. 1

[0032] Fig. 3 is a side view of another mobile robot according to the invention, Fig. 4 is a side view of another mobile robot,

[0033] Fig. 5 is a cross-section of the mobile robot according to Fig. 4.

[0034] Figures 1 and 2 show an embodiment of the mobile robot with a robot leg.

[0035] In Fig. 1, an arrow points from top to bottom and thus indicates the viewing direction for Fig. 1.

[0036] In the exemplary embodiment, a long threaded rod 2 with an external thread and an axially running groove is used for the up and down movement. The threaded rod 2 runs through an opening in the robot body 1 that is rounded at the edges and slightly larger than the cross-section of the threaded rod 2. A rectangular frame 5 hangs below it, through which the threaded rod 2 is moved axially. Inside the frame 5, on the upper side facing the opening, a first ball bearing 6a designed for pressure is pushed onto the threaded rod 2. The first ball bearing 6a rests on a first nut 7a, the outside of which is provided with worm gear teeth. A long sleeve 10 firmly connects this first nut 7a to another nut 11, which in turn rests on a second ball bearing 6b designed for axial pressure. The rotating ring of this second ball bearing 6b rests on the frame 5.The two nuts 7a, 11 and the sleeve 10 connecting them can rotate freely in the frame 5.

[0037] A motor 9 with a worm shaft 8a is attached to the side of frame 5 as the first drive. The worm shaft engages the worm gear of the first nut 7a, rotates it, and thus rotates the two nuts 7a and 11, thus displacing the threaded rod 2 within frame 5. A first pin 12 attached to frame 5 engages the groove of the threaded rod 2 to prevent it from rotating axially.

[0038] The robot body 1 rests on the frame 5 via a short spacer sleeve 4. Tension springs 3 at the upper corners of the frame 5 hold the threaded rod 2 centered in the opening of the robot body 1 and simultaneously allow angular movements of the threaded rod 2.

[0039] For the right / left movement, only the underside of the frame 5, which is opposite the opening in the robot body 1, is moved. A rod 13 connects a lower edge of the frame 5 through joints to the end face of a second, short threaded rod 14, which is provided with a groove.

[0040] A second nut 7b, which has worm teeth on its outside, is screwed onto this short threaded rod 14. A motor 16 is attached to the robot body as an additional drive, which rotates the second nut 7b using a worm shaft 8b. A U-shaped bracket 15, also attached to the robot body 1, on either side of the second nut 7b prevents the second nut 7b from axially shifting, and a second pin 12, which engages in the groove of the short threaded rod 14, prevents it from axially rotating. Ball bearings between the bracket and the second nut 7b reduce friction on the bracket 15. The rotating second nut 7b shifts the short threaded rod 14 within the U-shaped bracket 15 and thus changes the right / left angle of the long threaded rod 2 of the robot leg by means of the linkage and frame 5.

[0041] Attached to the lower edge of frame 5, at right angles to the left / right shift rod, is another, identically constructed rod with a short threaded rod and a nut, rotated by a worm gear, in a U-shaped bracket. These move the robot leg forward / backward.

[0042] Alternatively, any type of linear actuator can be used for right / left shifting and forward / backward shifting.

[0043] Instead of the worm gear for the up / down movement, the nut can alternatively have a gear on its outside instead of the worm wheel, which is driven by a pinion on the motor axis, which then runs parallel to the threaded rod.

[0044] Depending on the speed of the motor, a reduction gear may be required.

[0045] To increase the speed of movement, a rectangular rack can be used as an alternative to a threaded rod. This eliminates the need for a groove to prevent axial rotation and increases the speed of movement. However, for fine control, it requires a motor with a reduction gear or a stepper motor instead of the nut, worm drive, and simple motor.

[0046] Figure 3 shows another embodiment of the mobile robot with a robot leg. For the up and down movement, a long threaded rod 2 with an external thread and an axially extending groove 17 is used in this embodiment. The threaded rod 2 runs through an opening 22 in the robot body 1 that is rounded at the edges and slightly larger than the cross-section of the threaded rod 2. The opening 22 in the robot body 1 can be continuous. The threaded rod 2 can extend through the continuous opening 22 in the robot body 1. Below the opening 22 is a U-shaped frame 5 through which the threaded rod 2 is axially displaced.

[0047] Inside the frame 5, on the upper side facing the opening 22, a spacer sleeve 4 is pushed onto the threaded rod. The spacer sleeve 4 is firmly connected to the frame 5 and forms a sliding bearing for the axial movement of the threaded rod 2. The threaded rod 2 extends through an opening of a first ball joint 18a. The robot leg is attached to the robot body 1 through the first ball joint 18a. The first ball joint 18a allows angular movements of the threaded rod 2 together with the frame 5.

[0048] A first ball bearing 6a, designed for thrust, rests on the first ball joint 18a. The first ball bearing 6a is pushed onto the threaded rod 2. The first ball bearing 6a rests on a first nut 7a, the outer surface of which is designed as a spur gear. This first nut 7a rests on a second ball bearing 6b, designed for axial thrust. The rotating rings of the two ball bearings 6a and 6b rest on the nut 7a. The nut 7a can rotate freely in the frame 5. A long sleeve 10 rests on the ball bearing 6b. The long sleeve 10 runs through the frame 5 and is connected to it. The two sleeves 4 and 10 connected to the frame prevent axial movement of the first nut 7a along the threaded rod 2 and relative to the frame 5.

[0049] A motor 9 with a first pinion 19a is attached to the side of the frame 5 as the first drive. The first pinion 19a engages the gear of the first nut 7a, rotates it, and thus rotates the nut 7a, displacing the threaded rod 2 within the frame 5. A pin 12 attached to the frame 5 engages the groove of the threaded rod 2 to prevent it from rotating axially.

[0050] Tension springs 3 at the upper corners of the frame 5 prevent the frame 5 from rotating radially around the threaded rod 2 and allow angular movements of the frame 5 and thus of the threaded rod 2 around the ball joint 18. For right / left movement, only the underside of the frame 5, which is opposite the opening 22 in the robot body 1, is moved. A plain bearing 20 is connected to the frame 5 by means of the long sleeve 10. Two cardan joints 21 are attached to the outside of the plain bearing 20 at an angle of 90°. The cardan joint 21 is connected on the one hand to the plain bearing 20 and on the other hand to a short threaded rod 14. The cardan joint 21 allows variable angular positions of the short threaded rod 14 with the threaded rod 2. The cardan joint 21 blocks axial rotation of the short threaded rod 14.

[0051] A second nut 7b, the outer side of which is designed as a spur gear, is screwed onto this short threaded rod 14. A motor 16 is attached to the robot body 1 as an additional drive, which motor rotates the second nut 7b by means of a second pinion 19b. A U-shaped holder 15, also attached to the robot body 1 via a second ball joint 18b, on either side of the second nut 7b prevents the second nut 7b from moving axially. The short threaded rod 14 has no groove, since the universal joint 21 prevents axial rotation of the short threaded rod 14. The rotating second nut 7b moves the short threaded rod 14 within the U-shaped holder 15 and thus changes the right / left angle of the long threaded rod 2 of the robot leg by means of the universal joint 21, the slide bearing 20 and the frame 5.

[0052] Attached to the lower edge of frame 5, at right angles to the left / right shift rod, is another, identically constructed rod with a short threaded rod and a nut turned by the pinion in a U-shaped bracket. These move the robot leg forward / backward.

[0053] Alternatively, any type of linear actuator can be used for right / left shifting and forward / backward shifting.

[0054] Depending on the speed of the motor, a reduction gear may be required.

[0055] To increase the speed of movement, a rectangular rack can be used as an alternative to a threaded rod. This eliminates the need for a groove to prevent axial rotation and increases the speed of movement. However, for fine control, it requires a motor with a reduction gear or a stepper motor instead of the nut, gear, and simple motor.

[0056] The robot leg can be arranged within the robot body. The threaded rod 2 can extend through a continuous opening 22 in the robot body.

[0057] Figure 4 shows another embodiment of the mobile robot with a robot leg. Figure 5 shows a cross-section through the mobile robot according to Figure 4 along section AA.

[0058] For the up and down movement, the exemplary embodiment uses a long threaded rod 2 with an external thread and an axially extending groove 17. The threaded rod 2 runs through an opening 22 in the robot body 1 that is rounded at the edges and slightly larger than the cross-section of the threaded rod 2. The opening 22 in the robot body 1 can be continuous. The threaded rod 2 can extend through the continuous opening 22 in the robot body 1. This advantageously allows the mobile robot to be designed to be particularly compact. A U-shaped frame 5, through which the threaded rod 2 is axially displaced, is located below the opening 22.

[0059] Inside the frame 5, on the upper side facing the opening 22, a spacer sleeve 4 is pushed onto the threaded rod. The spacer sleeve 4 is firmly connected to the frame 5 and forms a sliding bearing for the axial movement of the threaded rod 2. The threaded rod 2 extends through an opening of a first ball joint 18a. The robot leg is attached to the robot body 1 through the first ball joint 18a. The first ball joint 18a allows angular movements of the threaded rod 2 together with the frame 5.

[0060] A first ball bearing 6a, designed for pressure, rests on the first ball joint 18a. The first ball bearing 6a is pushed onto the threaded rod 2. The first ball bearing 6a rests on a first nut 7a, the outer side of which is designed as a spur gear. This first nut 7a rests on a second ball bearing 6b, designed for axial pressure. The rotatable rings of the two ball bearings 6a and 6b rest on the nut 7a. The nut 7a can rotate freely in the frame 5. A long sleeve 10 rests on the ball bearing 6b. The long sleeve 10 runs through the frame 5 and is connected to it. The two sleeves 4 and 10 connected to the frame prevent axial movement of the first nut 7a along the threaded rod 2 and relative to the frame 5. A motor 9 with a first pinion 19a is attached to the side of the frame 5 as the first drive.The first pinion 19a engages with the gear of the first nut 7a, rotates it, thereby rotating the nut 7a and displacing the threaded rod 2 within the frame 5. A first pin 12 fixed to the frame 5 engages in the groove of the threaded rod 2 so that it does not rotate axially.

[0061] Tension springs 3 at the upper corners of the frame 5 prevent radial rotation of the frame 5 around the threaded rod 2 and allow angular movements of the frame 5 and thus of the threaded rod 2 around the ball joint 18.

[0062] For right / left movement, two servomotors 23a and 23b are connected to the underside of frame 5. Each of the two servomotors 23a and 23b is provided with an arm 24a and 24b, which can be rotated with the respective servomotor 23a and 23b within the angular range 25a and 25b. A rod 13a and 13b is movably connected to each of the arms 24a and 24b. The rods 13a and 13b are attached to the robot body 1. Deflection of the arm 24a or 24b away from the robot body 1 pulls the servomotor 23a or 23b toward the robot body 1, causing the frame 5 to rotate about the first ball joint 18a and angle the threaded rod 2. The rods 13a and 13b are arranged approximately at right angles to each other, so that the two servo motors 23a and 23b can move the threaded rod 2 in the two horizontal dimensions.

[0063] The robot leg can be arranged within the robot body. The threaded rod 2 can extend through a continuous opening 22 in the robot body.

[0064] List of reference symbols

[0065] 1 robot body

[0066] 2 bars

[0067] 3 tension spring

[0068] 4 spacer sleeve

[0069] 5 frames

[0070] 6a first ball bearing

[0071] 6b second ball bearing 7a first nut

[0072] 7b second mother

[0073] 8a Worm shaft

[0074] 8b Worm shaft

[0075] 9 Engine

[0076] 10 sleeves

[0077] 11 Mother

[0078] 12 pins

[0079] 13 rods

[0080] 13a first rod 13b second rod

[0081] 14 short threaded rods

[0082] 15 Bracket

[0083] 16 Drive

[0084] 17 Axially extending groove 18a first ball joint 18b second ball joint 19a first pinion

[0085] 19b second pinion

[0086] 20 plain bearings

[0087] 21 Cardan joint

[0088] 22 Opening

[0089] 23a first servo motor

[0090] 23b second servo motor 24a first arm

[0091] 24b second arm 25a first angle range

[0092] 25b second angular range

Claims

REQUIREMENTS 1. Mobile robot with a robot body (1) and at least one robot leg, characterized in that the robot leg comprises an axially displaceable rod (2) which is pivotably guided on the robot body (1), wherein means (6, 7a, 8a, 9, 10, 11) for axially displacing the rod (2) and means (7b, 8b, 14, 15, 16) for pivoting the rod (2) are provided, wherein at the location of the robot body (1) provided for the robot leg there is an opening (22) in which the rod (2) can be moved vertically and at variable angles relative to the opening.

2. Mobile robot according to claim 1, characterized in that the opening (22) of the robot body (1) is continuous.

3. Mobile robot according to claim 1 or 2, characterized in that the rod (2) is a first threaded rod with an external thread and an axially extending groove, wherein the external thread engages in an internal thread which is rotatably and pivotably, but not axially displaceably, connected to the robot body (1) and wherein a pin (12) is provided in the groove to prevent radial rotation of the rod (2), that a first drive (9) for rotating the internal thread on the rod (2) is provided as a means (6, 7a, 8a, 9, 10, 11) for axially displacing the rod (2), and that at least one further drive (16) is provided as a means (7b, 8b, 14, 15, 16) for pivoting the rod, which is directly or indirectly connected to the first threaded rod.

4. Mobile robot according to claim 1, 2 or claim 3, characterized in that two drives (16) are provided as means for pivoting the rod (2), which are offset from each other and connected directly or indirectly to the first threaded rod.

5. Mobile robot according to one of claims 1 to 4, characterized in that the rod (2) is designed as a threaded rod in some areas.

6. Mobile robot according to one of claims 1 to 5, characterized in that the rod (2) is a preferably rectangular rack, and that as a means to A mobile robot according to any one of claims 1 to 6, characterized in that a control device is provided. A mobile robot according to any one of claims 1 to 7, characterized in that a tilt sensor is provided.

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