Self-propelled transport robot

Abstract

The invention relates to a self-propelled transport robot having a platform (100) movable on omnidirectional wheels (110), the platform comprising a front section (10), a middle section (20) and a rear section (30), the middle section (20) including a sandwich structure (21) comprising a bottom panel (22) and a reinforcement layer, which is arranged between the bottom panel (21) and a top panel (23), wherein the front section (10) comprises a front receiving space (11) and the rear section (30) comprises a rear receiving space (31), the front receiving space (11) accommodating batteries (12) to power the transport robot and the rear receiving space (31) accommodating electronics (32) to control the transport robot.

Description

[0001] Self-propelled transport robot

[0002] The invention relates to a self-propelled transport robot.

[0003] Self-propelled transport robots such as automated guided vehicles are often used in production plants for transporting a payload between different stations during the production without direct human assistance. A particular use for such self-propelled transport robots is transporting vehicle body parts to a measuring area where the body parts that are fixed on the self-propelled transport robot are measured by a tactile or optical measurement. Such a self-propelled transport robot is disclosed for example in US 2012 / 0214194 A1 , which presents a transport robot comprising a platform that is movable on omnidirectional wheels. The platform comprises four omnidirectional wheels, wherein the wheels are connected in pairs to a tubular axle. The two tubular axles are installed to the platform at a front part and a rear part of the platform. A reinforcement frame comprising a sandwich structure is positioned in a middle section of the platform. The reinforcement frame surrounds an open base that accommodates batteries and controls of the self-propelled transport robot.

[0004] Although the known self-propelled transport robot serves well for its purpose, there are drawbacks when trying to upscale the known system. In particular, providing a platform with greater dimensions, in particular a higher length of the platform, the known construction of a self-propelled transport robot has limits. In particular, in case that the self-propelled transport robot shall be used for positioning vehicle body parts in a measuring area, it is crucial for the measurement that the platform of the self-propelled transport robot is very stiff. Otherwise, the risk of measuring errors is increased.

[0005] It has been shown in FEM simulations that a platform having a higher length tends to bend due to the payload. Thus, a vehicle body part fixed to the platform cannot be positioned accurately enough for high precision measurement.

[0006] It is thus an object of the present invention to provide a self-propelled transport robot that has an increased stiffness and provides for a high precision positioning or alignment of vehicle body parts for measurement.

[0007] This object is solved by a self-propelled transport robot according to claim 1 . The inventive self-propelled transport robot has a platform that is movable on omnidirectional wheels. The platform comprises a front section, a middle section and a rear section. The middle section includes a sandwich structure comprising a bottom panel and a reinforcement layer, which is arranged between the bottom panel and a top panel. The front section comprises a front receiving space and the rear section comprises a rear receiving space, wherein the front receiving space accommodates batteries to power the transport robot, and the rear receiving space accommodates electronics to control the transport robot.

[0008] Preferably, the sandwich structure is a box-shaped structure, having side panels, the bottom panel and the top panel. The side panels preferably connect the bottom panel to the top panel. The box-like sandwich structure is preferably continuous in a rectangular dimension. It is possible that a box-shaped structure, in particular a cuboid structure comprising the bottom panel and sidewalls, wherein the space between the bottom panel and the sidewalls is filled with a reinforcement layer, is attached to the top panel. This box-like or cuboidal sandwich structure preferably extends along the middle section. The cuboidal sandwich structure is preferably continuous.

[0009] It has been shown, in particular by FEM simulations, that a platform having the electronics and the batteries installed outside of the middle section, and further providing a sandwich structure in the middle section enhances the stiffness of the platform. The deformations due to the payload installed on the platform, are significantly reduced, thus providing the necessary stability for a high precision measurement of a vehicle body or vehicle body part. In particular, the platform is stiff enough to allow any tactile or optical measurement to take place, while the platform rests on the omnidirectional wheels. It is thus not necessary to position the platform on or with positioning elements for precise alignment of the vehicle body part to a predetermined system of coordinates.

[0010] According to a preferred embodiment of the invention, the reinforcement layer comprises a honeycomb structure. The honeycomb structure is preferably arranged such that the honeycomb walls extend from the bottom panel to the top panel. The use of a honeycomb structure provides a very stiff reinforcement layer while keeping the weight of the platform low. As a result, the self-propelled transport robot can be used in an energy-efficient manner.

[0011] Preferably, the omnidirectional wheels are attached to the top panel outside the sandwich structure. The omnidirectional wheels serve as supporting points not only during movement of the transport robot, but also when the transport robot is held stationary, for example in a measuring area. The stiffness of the omnidirectional wheels itself provide for a precise positioning of the self-propelled transport robot, such that it fits sufficiently into a predefined system of coordinates. However, it has been shown that positioning the omnidirectional wheels outside of the sandwich structure provides for several advantages. First, the top panel is already stabilized in the area where the omnidirectional wheel is mounted, such that an additional sandwich structure is not necessary. Rather, the sandwich structure should reinforce parts of the platform that are otherwise weak or prone to bending. Second, positioning the omnidirectional wheels outside of the sandwich structure allows for a low-floor design of the transport robot. This also keeps the centre of gravity low which furthero stabilizes the self- propelled transport robot.

[0012] According to the invention, the front section of the platform comprises a front-receiving space. The rear section of the platform comprises a rear-receiving space. The receiving spaces are formed by the top layer overlapping the sandwich structure. The space underneath the top panel, which is further delimited by front or rear sidewalls of the sandwich structure, is easily accessible and, thus, batteries and / or electronics can be replaced fast. This improves the maintainability of the self-propelled transport robot. Moreover, it has been shown in FEM simulations that arranging the batteries and / or the electronics outside of the sandwich structure, in particular in the front section and in the rear section, further avoids bending of the platform due to the payload. The platform rather allows for a precise alignment of its payload, in particular vehicle body parts, in a measuring area.

[0013] According to a preferred embodiment of the present invention, the front section and the rear section each have a length in the longitudinal direction of the, preferably essentially rectangular, platform, which is not more than 1 / 3, in particular not more than 1 / 4, in particular not more than 1 / 5, in particular not more than 1 / 6, in particular not more than 1 / 8, of the length of the middle section. This design ensures that a sufficient area of the platform is reinforced by the sandwich structure and its reinforcement layer to improve the overall stiffness of the platform.

[0014] The front receiving space may be delimited in the longitudinal direction by the sandwich structure and a, preferably vertical, front panel and the rear receiving space is delimited in the longitudinal direction by the sandwich structure and a, preferably vertical, rear panel. The front panel and the rear panel may be part of a surrounding covering that is attached to the edges of the top panel. The covering may include the front panel, the rear panel and lateral covering panels. The front panel, the rear panel and the lateral panels may cover the underside of the top panel. The front panel, the rear panel and the side panels each may have a height that is at least the height of the sandwich structure.

[0015] The front receiving space is preferably defined as a space underneath the top panel which is delimited in the longitudinal direction by the sandwich structure, in particular front wall of the box-like sandwich structure, and the front panel. The front receiving space thus forms a channel in which the batteries can be installed. The same applies basically to the rear receiving space. The rear receiving space is defined preferably as a space underneath the top panel which is delimited in the longitudinal direction of the platform by the sandwich structure, in particular a rear wall of the box-like sandwich structure, and the rear panel. The rear receiving space is formed as a channel. The electronics for controlling the transport robot can be installed in this channel or the rear receiving space.

[0016] In a preferred embodiment of the inventive self-propelled transport robot, the front panel and the rear panel each define a longitudinal end of the platform. In other words, the front panel and the rear panel cover the space between the top panel and a ground or floor along the front or rear edge of the top panel. Additionally, side panels can be attached to the top panel, the side panels also covering the distance between a lateral edge of the top panel and the ground or floor. However, it is preferred that the front, rear, and side panels each have some ground clearance to allow the robot to move freely on the omnidirectional wheels.

[0017] Furthermore, the front section and / or the rear section may be reinforced by at least one longitudinal beam extending from the sandwich structure. The longitudinal beam additionally reinforces the platform, in particular the top panel, to avoid bending of the platform due to the payload. This further stiffens the platform and thus allows for a high precision measurement of vehicle body parts carried by the platform.

[0018] The longitudinal beam may be formed by an extension of a lateral sidewall of the sandwich structure. As already described, the sandwich structure may be formed by the bottom panel, four sidewalls, in particular two lateral sidewalls, a front sidewall and a rear sidewall, and the top panel. The sidewalls, the bottom panel and the top panel delimit a reinforcement space that is, especially completely, filled with the reinforcement layer. To reinforce the top panel additionally in the front section or the rear section, in particular in the area of the front receiving space and the rear receiving space, the lateral sidewalls may be extended beyond the box-like sandwich structure. The lateral sidewalls may extend beyond the front sidewall and / or the rear sidewall, thus forming the longitudinal beams. Each longitudinal beam may extend from the sandwich structure to the front panel or the rear panel. The longitudinal beams are preferably attached or fixed to the top panel.

[0019] In a further preferred embodiment of the present invention, the platform includes at least four, in particular six, precision plates. The at least four, in particular six, precision plates may be mounted to the bottom of the bottom panel in a regular pattern. The precision plates are preferably configured to position the platform precisely in a measuring area. In particular, the precision plates are manufactured such that they provide for a high precision positioning or alignment of the platform in a z-direction. In order to achieve such a high precision positioning, the platform may be lowered onto the ground or floor, in particular onto high precision positioning elements installed on or in the floor. In order to do so, the omnidirectional wheels may be suspended in a wheel suspension that allows for lifting and lowering the platform.

[0020] Two of the precision plates mounted to the bottom of the bottom panel, may include form-fit protrusions designed to be inserted into centering holes in the floor of a measuring area to precisely align the platform in a measurement position. Using additional form-fit protrusions, lowering the platform onto the floor in a measuring area and thus engaging centering holes in the floor, not only provides for a high precision positioning in a z-direction, but also aligns the platform in x- and y-directions. Therefore, the self-propelled transport robot, in particular the platform, can be aligned in a very high precision manner within a predetermined or predefined system of coordinates. This allows for an accurate measurement of vehicle body parts mounted to the self-propelled transport robot.

[0021] The invention is described in more detail below by means of a preferred embodiment with reference to the accompanying drawings, wherein Fig. 1 shows a perspective underside view of a self-propelled transport robot according to a preferred embodiment of the invention.

[0022] The self-propelled transport robot according to Fig.1 includes a platform 100 that is movable on omnidirectional wheels 110. In the embodiment shown in Fig. 1 , the platform 100 includes six omnidirectional wheels 110. Each of the omnidirectional wheels 110 is integrated into a wheel suspension that may include a shock absorber and a lifting unit for lifting or lowering the platform with respect to the ground or floor. In other words, the omnidirectional wheels 110 can be lifted to lower the platform 100, in particular until the platform 100 reaches the floor. Contrary thereto, the lifting unit may push the omnidirectional wheels 110 downwards to lift the platform 100. When the platform 100 is lowered, the self-propelled transport robot may be in a measuring state. When the platform 100 is lifted, the self-propelled transport robot may be in a movable state. In the measuring state, the omnidirectional wheels 110 are preferably fully retracted so as not to extend beyond support points that contact the floor. In particular, the omnidirectional wheels may not extend beyond a bottom panel 22 of a sandwich structure 21 in the measuring state. In the movable state, the omnidirectional wheels 110 instead should extend beyond the bottom panel 22 in order to provide sufficient ground clearance for moving the self-propelled transport robot smoothly.

[0023] The platform 100 can be divided into three sections, at least virtually. In particular, the platform 100 includes a front section 10, a middle section 20 and a rear section 30. The middle section 20 is arranged between the front section 10 and the rear section 30. In the middle section, the platform 100 includes a sandwich structure comprising a bottom panel 22 and a reinforcement layer. The reinforcement layer is not shown in Fig. 1 , but is arranged completely between the bottom panel 22 and a top panel 23. The top panel 23, however, has greater dimensions than the bottom panel 22. In particular, the top panel 23 overlaps the bottom panel 22 at all of its sides. The top panel 23 and the bottom panel 22 are connected by sidewalls 24. Thus, the sandwich structure, in particular the bottom panel 22 and the sidewalls 24 form a box-like shape. The box-like shape in particular forms a cubic shape. The bottom panel 22 may have a rectangular shape. In addition, the cross section of the sandwich structure 21 may have a rectangular shape.

[0024] The sandwich structure 21 may include four sidewalls 24, delimiting an inner space that is preferably completely filled with a reinforcement layer. The reinforcement layer may be a honeycomb structure. In case of a honeycomb structure, the honeycomb walls preferably extend between the bottom panel 22 and the top panel 23. The four sidewalls 24 comprise two lateral sidewalls 24c that extend in parallel to each other. The lateral sidewalls 24c are connected by a front sidewall 24a and a rear sidewall 24b. The top panel 23 extends over the front sidewall 24a, the rear sidewall 24b and the lateral sidewall 24c.

[0025] The top panel 23 extending beyond the lateral sidewalls 24c provide an accommodation space for the omnidirectional wheels 110. The omnidirectional wheels 110 thus are mounted to the top panel 23, in particular the lateral parts of the top panel 23 that overlap the sandwich structure 21 on the lateral sides.

[0026] The platform 100 further includes covering panels that are attached to the top panel 21 , in particular on the outer circumference of the top panel 23. The covering panels may be suspended from the outer edges of the top panel 23. The covering side panels together form a rectangular covering frame extending vertically underneath the top panel 23.

[0027] As shown in Fig. 1 , the length of the sandwich structure 21 defines the middle section 20. The middle section 20 is the section of the platform 100 that includes the sandwich structure 21 . Adjacent the middle section 20 is the front section 10 on the one side and the rear section 30 on the other side. The front section 10 includes a front receiving space that is delimited by the front sidewall 24a of the sandwich structure 21 , by the front panel 13 and by the top panel 23. In particular, the overlapping part of the top panel 23 delimits the front receiving space 11 . Thus, the front receiving space 11 forms a channel that is able to accommodate batteries. The electric batteries may be connected to motors of the transport robot, so that the batteries 12 provide the necessary power for moving the self-propelled transport robot. In the rear section 30, the rear receiving space 31 is also delimited by the rear sidewall 24b of the sandwich structure and the rear panel 33 attached to the top panel 23. The rear receiving space is further delimited by the overlapping part of the top panel 23 that extends over the sandwich structure 21 . Thus, the rear receiving space 31 also forms a channel for accommodating the electronics of the self-propelled transport robot.

[0028] By arranging the batteries 12 in the front section 10 and the electronics 32 in the rear section 30, and simultaneously providing a reinforced middle section 20, the platform 100 is very stable and stiff. Thus, the platform 100 is less likely prone to deformation and is therefore very suitable for high precise measurement of body parts.

[0029] In order to enhance the suitability of high precision measurement, the sandwich structure 21 may have precision plates 26 mounted to the bottom of the bottom panel 22. The precision plates are preferably mounted in a regular pattern to the bottom panel 22. At least two of the precision plates may include protrusions that are able to interact with corresponding holes in the floor of a measuring area. Thus, a form-fit connection may be established in the measuring area, thus allowing to a high precision positioning of the transport robot. In particular, the platform may thus be arranged precisely within a predetermined or predefined system of coordinates in each direction, in particular in x-, y- and z-directions.

[0030] As further shown in Fig. 1 , the front panel, the rear panel and the lateral side panels together form a rectangular frame of a covering. The frame preferably covers the omnidirectional wheels 110. The lateral side panels 25 may be easily uninstalled from the platform 100 in order to easily reach the omnidirectional wheels 110. Thus, the omnidirectional wheels 110 can be replaced easily and fast during maintenance. This improves the overall operation time of the self- propelled transport robot.

[0031] The top panel 23 may be formed by a grid plate including a plurality of mounting holes.

[0032] The mounting holes can serve for mounting posts or columns to the platform. The posts or columns may then form support structures for a vehicle body part. Thus, the vehicle body part can be attached to the support structures for high precision measurement.

[0033] The materials used for the different parts of the platform 100 preferably include steel or aluminum. In particular, the reinforcement layer may be made of an aluminum honeycomb structure. Reference signs

[0034] 100 platform

[0035] 110 omnidirectional wheels

[0036] 10 front section

[0037] 11 front receiving space

[0038] 12 batteries

[0039] 13 front panel

[0040] 20 middle section

[0041] 21 sandwich structure

[0042] 22 bottom panel

[0043] 23 top panel

[0044] 24 sidewall

[0045] 24a front sidewall

[0046] 24b rear sidewall

[0047] 24c lateral sidewall

[0048] 25 lateral side panel

[0049] 25 longitudinal beam

[0050] 26 precision plate

[0051] 27 protrusion

[0052] 30 rear section

[0053] 31 rear receiving space

[0054] 32 electronics

[0055] 33 rear panel

Claims

Claims1 . Self-propelled transport robot having a platform (100) movable on omnidirectional wheels (1 10), the platform comprising a front section (10), a middle section (20) and a rear section(30), the middle section (20) including a sandwich structure (21 ) comprising a bottom panel (22) and a reinforcement layer, which is arranged between the bottom panel (21 ) and a top panel (23), wherein the front section (10) comprises a front receiving space (1 1 ) and the rear section (30) comprises a rear receiving space (31 ), the front receiving space (11 ) accommodating batteries (12) to power the transport robot and the rear receiving space(31 ) accommodating electronics (32) to control the transport robot.

2. Self-propelled transport robot according to claim 1 characterized in that the reinforcement layer comprises or consists of a honeycomb structure.

3. Self-propelled transport robot according to claim 1 or 2 characterized in that the omnidirectional wheels (110) are attached to the top panel (23) outside the sandwich structure (21 ).

4. Self-propelled transport robot according to any of the preceding claims characterized in that the front section (10) and the rear section (30) each have a length in the longitudinal direction of the, preferably essentially rectangular, platform (100), which is not more than 1 / 3, in particular not more than 1 / 4, in particular not more than 1 / 5, in particular not more than 1 / 6, in particular not more than 1 / 8 of the length of the middle section (20).

5. Self-propelled transport robot according to any of the preceding claims characterized in that the front receiving space (11 ) is delimited in the longitudinal direction by the sandwich structure (21 ) and a, preferably vertical, front panel (13) and the rear receiving space (31 ) is delimited in the longitudinal direction by the sandwich structure (21 ) and a, preferably vertical, rear panel (33).

6. Self-propelled transport robot according to claim 5 characterized in that the front panel (13) and the rear panel (33) each define a longitudinal end of the platform (100).

7. Self-propelled transport robot according to any of the preceding claims characterized in that the front section (10) and / or the rear section (30) is reinforced by at least one longitudinal beam extending from the sandwich structure (21).

8. Self-propelled transport robot according to claim 7 characterized in that the longitudinal beam (25) is formed by an extension of a lateral sidewall (24) of the sandwich structure (21).

9. Self-propelled transport robot according to any of the preceding claims characterized in that at least four, in particular six, precision plates (26) are mounted to the bottom of the bottom panel (22) in a regular pattern.

10. Self-propelled transport robot according to claim 9 characterized in that two of the precision plates (26) include form-fit protrusions (27) designed to be inserted into centering holes in the floor of a measuring area to precisely align the platform (100) in a measurement position.

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