CN213749089U

CN213749089U - Acceptance parking platform of automatic driving equipment offline acceptance workshop

Info

Publication number: CN213749089U
Application number: CN202022943815.7U
Authority: CN
Inventors: 温宽昌; 李瑞峰; 常骐川; 黄小春; 霍光磊; 梁培栋
Original assignee: Fujian Quanzhou HIT Research Institute of Engineering and Technology
Current assignee: Fujian Quanzhou HIT Research Institute of Engineering and Technology
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2021-07-20
Anticipated expiration: 2030-12-07

Abstract

The utility model discloses an acceptance parking platform between acceptance shop under automatic pilot unit line, including horizontal platform, park positioner and park the fixed point device, horizontal platform is last to have transversely seted up front wheel location section groove and rear wheel location section groove, park positioner and set up respectively in front wheel location section groove and rear wheel location section inslot, park positioner and fill out the many girder steels that bear of front wheel location section groove or rear wheel location section groove including arranging, the supporting driving cylinder that each bottom that bears the girder steel was equipped with respectively and respectively bear the guide structure that the both ends of girder steel were equipped with respectively, bear the girder steel and can make its upper surface flush or many bear the girder steel upper surfaces and constitute the recessed wheel groove of straggling under supporting the drive support of driving cylinder. The checking and accepting parking platform with the structure can achieve better automation work, has high automation performance, can achieve better fixed point positioning to improve the detection precision during checking and accepting, and is stable and reliable in overall structure setting.

Description

Acceptance parking platform of automatic driving equipment offline acceptance workshop

Technical Field

The utility model relates to an automatic driving equipment's parking platform field.

Background

Along with the rapid development of intelligent science and technology, autopilot equipment products are more and more, autopilot's detection is indispensable and will reach the detection condition of high standard, just can go off the production line and use, because autopilot equipment is unmanned and all need have dedicated acceptance parking platform to park in the off-line acceptance process or later detection and just can carry out the accurate detection of high standard, the requirement to acceptance parking platform is different according to different detection project at present, some only need in regional scope can, but the position requirement to parking to detecting the multi-thread lidar condition has fixed position, only can reach the accurate detection of high standard under the basis of parking according to fixed position.

At present, small-sized automatic driving equipment can be easily operated when the automatic driving equipment is parked at a fixed position, but the operation of the automatic driving equipment with larger size and larger weight is extremely difficult, multiple adjustments are needed, automatic operation is not available, and the working efficiency is low.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an automatic driving equipment that can reach automatic positioning and park rolls off production line inspection workshop examine and accept parking platform to solve the problem that exists among the prior art.

In order to achieve the above purpose, the technical scheme of the utility model is that: an acceptance parking platform of an off-line acceptance workshop of automatic driving equipment is characterized by comprising a horizontal platform for bearing the automatic driving equipment, a parking positioning device for automatically adjusting the forward parking position of the automatic driving equipment and a parking positioning device for automatically adjusting the tire positioning position of the automatic driving equipment, a front wheel positioning section groove and a rear wheel positioning section groove are transversely arranged on the horizontal platform, the parking positioning device is respectively arranged in the front wheel positioning section groove and the rear wheel positioning section groove, the parking positioning device comprises a plurality of bearing steel beams which are arranged and filled in the front wheel positioning section groove or the rear wheel positioning section groove, a supporting driving cylinder which is respectively arranged at the bottom of each bearing steel beam and a guide structure which is respectively arranged at the two ends of each bearing steel beam, the bearing steel beams can enable the upper surfaces of the bearing steel beams to be flush with the upper surface of the horizontal platform or the upper surfaces of the bearing steel beams to form staggered and concave wheel grooves under the driving support of the supporting driving cylinder.

And the bearing steel beam is provided with a pressure sensor.

Park the fixed point device and include rear wheel fixed point adjusting device and front wheel fixed point adjusting device, rear wheel fixed point adjusting device corresponds and sets up respectively at the both ends in rear wheel positioning section groove, and it includes rear wheel removal ejector pad and rear wheel ejector pad drive, the rear wheel removes the ejector pad setting on the horizontal platform upper surface and stride across rear wheel positioning section groove perpendicularly rear wheel ejector pad drive sets up and connects the rear wheel outside the tip in rear wheel positioning section groove and remove the ejector pad and be used for driving its removal, be equipped with rear wheel ejector pad guide structure on the rear wheel removes the ejector pad.

The front wheel fixed point adjusting device is arranged at two ends of the front wheel positioning section groove respectively and comprises a front wheel moving push block and a front wheel push block drive, the front wheel moving push block is arranged on the upper surface of the horizontal platform and vertically crosses the front wheel positioning section groove, the front wheel push block drive is arranged outside the end part of the front wheel positioning section groove and is connected with the front wheel moving push block for driving the front wheel moving push block to move, and a front wheel push block guide structure is arranged on the front wheel moving push block.

Front wheel fixed point adjusting device sets up at the intermediate point bilateral symmetry in front wheel location section groove, and it includes that T type removes ejector pad, T type ejector pad drive and T type ejector pad guide structure, T type removes the ejector pad and personally submits T type form for its truncation, and it sets up on the horizontal platform upper surface and strides front wheel location district section groove perpendicularly, the sliding tray has been seted up respectively on the both sides edge in front wheel location district section groove, T type that T type removed the ejector pad erects the arm both ends and is equipped with the connecting rod embedding respectively in the sliding tray that corresponds, T type ejector pad drive sets up respectively in the sliding tray and connects the connecting rod to be used for driving its removal, T type ejector pad guide structure sets up between connecting rod and sliding tray.

By adopting the technical scheme, utility model's beneficial effect is: the acceptance check parking platform with the structure can achieve better automation work, namely, the automation performance is high, the structure setting is firstly carried out on the in-and-out direction positioning through the parking positioning device, the wheel axial direction fixed point is carried out through the parking positioning device, and the two processes can automatically adjust the position of the automatic driving equipment. In addition, the application range of the platform is large by setting the positions and the groove widths of the front wheel positioning section groove and the rear wheel positioning section groove, the platform is suitable for automatic driving equipment with different sizes, the adjustment of different fixed point positioning positions can be achieved, and the universality is high. In addition, the structure of the parking positioning device is arranged to realize the positioning of the wheels by forming the positions for the wheel depressions, and the position for adjusting the positioning of the wheels is realized by adjusting the positions of the lowest points of the wheel depressions.

Drawings

Fig. 1 is a schematic structural diagram of an off-line acceptance workshop of the multi-line laser radar automatic driving equipment related to the utility model;

fig. 2 and fig. 3 are schematic structural diagrams of different states of the parking positioning device of the acceptance platform of the present invention;

fig. 4 is a schematic structural view of a parking point device of the acceptance and stop platform of the present invention.

In the figure:

the automatic driving apparatus 100; a workshop body 1; an entrance 11;

checking and accepting the parking platform 2; a horizontal platform 21; a front wheel positioning section groove 211; a rear wheel alignment section slot 212;

parking positioning device 22; a load-bearing steel beam 221; a support drive cylinder 222; a guide structure 223;

a pressure sensor 224; a wheel groove 225;

a parking pointing device 23; a rear wheel fixed point adjusting device 231; the rear wheel moving push block 2311;

a rear wheel pusher drive 2312; a rear wheel pusher guide 2313; a front wheel fixed point adjusting device 232;

a front wheel moving push block 2321; a front wheel push block drive 2322;

a front wheel pusher guide 2323; a T-shaped mobile push-block 2324;

a T-shaped push block drive 2325; a T-shaped pusher guide 2326; a sliding slot 2327; a connecting rod 2328;

acceptance detection means 3; a function detection device 31; a moving track 311;

a mobile cart 312; a target object 313; the detection device 32 is installed.

Detailed Description

In order to further explain the technical solution of the utility model, the following describes the utility model in detail through specific embodiments.

The utility model discloses a have the utility model discloses a multi-thread laser radar autopilot equipment's off-line acceptance workshop of acceptance parking platform of autopilot equipment off-line acceptance workshop, as shown in figure 1, figure 2, figure 3, figure 4, including workshop main part 1, acceptance parking platform 2, acceptance detection device 3 and acceptance control system (this system mainly includes the electrical system of circuit structure and the detecting system of the program part that work goes on, can not be seen in the figure). This off-line inspection and acceptance workshop is used for some unmanned autopilot who has multi-thread laser radar to patrol and examine, the detection of the multi-thread laser radar of working vehicle such as cleanness, it can use off the production line to detect qualified autopilot equipment, detect unqualifiedly then adjust on the return wire and change, often the automobile body bottom of these autopilot equipment includes front wheel and rear wheel, the rear wheel includes left rear wheel and right rear wheel usually, the front wheel then has two kinds, one kind is just in the middle part before only one, another kind is then including left front wheel and right front wheel, its multi-thread laser radar is installed the top surface middle part that sets up at the locomotive usually.

The utility model discloses in workshop main part 1 is the independent workshop of square, and its three sides are equipped with the wall body, unify the surrounding environment through the wall body, avoid other materials that influence the laser scanning result, avoid influencing the factor existence of testing result, and workshop main part 1's another side is access & exit 11. The acceptance detection device 3 is arranged close to a side wall body opposite to the gateway 11 in the workshop main body 1, the front end of the automatic driving equipment faces the acceptance detection device 3 when in detection use, and the acceptance control system is used for controlling the equipment traction device 5, the acceptance parking platform 2 and the acceptance detection device 3 in the workshop main body 1 to work.

The acceptance detection device 3 in the utility model comprises a function detection device 31 for detecting whether the laser scanning using function of the multi-line laser radar is normal or not and an installation detection device 32 for detecting whether the installation position of the multi-line laser radar is accurate or not; the installation detection device 32 is composed of a plurality of scanning marker posts vertically arranged according to a set distance position, the spacing distance between the scanning marker posts and the acceptance parking platform 2 is preferably not longer than the better scanning distance detected by laser scanning, the scanning marker posts are correspondingly transversely arranged in front of the acceptance parking platform 2, 3 spacing vertical arrangement is set as shown in the figure, the middle one is arranged right in front of a 0-direction angle of the multi-line laser radar during working, the two adjacent scanning marker posts are arranged at the same spacing distance, the height of each scanning marker post is preferably higher than the height of a vehicle when calculated from the height of the horizontal plane of the acceptance parking platform 2 so as to meet the scanning range of the multi-line laser radar, and the width of each scanning marker post is preferably about 5 cm; the function detecting device 31 includes a moving track 311, a moving cart 312, and a target object 313, where the moving track 311 is disposed at a preset distance position between the front of the checking and parking platform 2 and the mounting detecting device 31 according to the preset distance position, preferably not exceeding the preferable scanning distance of the laser scanning detection, the length of the moving track 32 is preferably greater than the width of the vehicle 1, in this embodiment, the moving stroke of the moving track is 2 meters, the moving cart 312 is mounted with a driving device for driving the moving cart 312 to move on the moving track 311, and the target object 313 is vertically mounted on the moving cart 312. The target object 313 is vertically arranged on the movable trolley 312, the target object 313 can be a human-shaped prop or other profiling props, the scanning marker post is arranged behind the target object 313, and the influence of the scanning marker post when the multi-line laser radar scans the target object can be avoided due to the structural arrangement.

The acceptance parking platform 2, as shown in the figure, is arranged on the bottom surface in the workshop main body 1 and is used for parking the automatic driving equipment 100, and comprises a horizontal platform 21 for bearing the automatic driving equipment 100, a parking positioning device 22 for automatically adjusting the forward parking position of the automatic driving equipment 100 and a parking positioning device 23 for automatically adjusting the tire positioning position of the automatic driving equipment 100; as shown in the figure, the specific structure related to the present embodiment is such that:

a rear wheel positioning section groove 212 is transversely formed in one side, facing the entrance 11, of the horizontal platform 21, and a front wheel positioning section groove 211 is transversely formed in the opposite side, facing the entrance 11, of the horizontal platform, the forming distances of the two grooves are set according to the axle distance range of a front wheel and a rear wheel of a common automatic driving equipment vehicle, and the forming widths of the grooves can be the same or different, so that the acceptance parking platform 2 can be suitable for positioning parking of various vehicles with different sizes; the parking positioning device 22 is respectively arranged in the front wheel positioning section groove 211 and the rear wheel positioning section groove 212, and comprises a plurality of bearing steel beams 221 which are arranged and filled in the front wheel positioning section groove 211 or the rear wheel positioning section groove 212, a supporting driving cylinder 222 which is respectively arranged at the bottom of each bearing steel beam 221, a guide structure 223 which is respectively arranged at two ends of each bearing steel beam 221, and a pressure sensor 224 which is arranged on each bearing steel beam 221, as shown in the figure, the bearing steel beams 221 can lift under the driving support of the supporting driving cylinder 222 and the limitation of the guide structure 223, the bearing steel beams 221 can lift until the upper surfaces of the bearing steel beams are flush with the upper surface of the horizontal platform 21 or descend until the upper surfaces of the plurality of bearing steel beams 221 form a wheel groove 225 which is concave and staggered, so as to achieve the positioning of the front wheels and the rear wheels of the vehicle in the front and rear direction of the horizontal platform 21, because the plurality of bearing steel beams 221 are arranged, therefore, when the wheel groove 225 is sunken, one bearing steel beam 221 at the lowest part of the wheel groove 225 can be controlled according to the wheel base of the vehicle, so that the wheel groove can be used for positioning the wheels of the vehicles with different sizes, in addition, each bearing steel beam 221 is provided with a pressure sensor 224 which can be used for sensing the positions of the front wheels and the rear wheels, namely the positions of the vehicles, and the bearing steel beam 221 at the lowest part can be automatically judged by the pressure sensors so as to form the wheel groove 225 when the wheels fall off or fall off, wherein the sunken shape formed by the falling or the falling of the wheel groove 225 is an arc shape fitting the circumferential surface of the wheel, the wheels can not move back and forth after being embedded into the wheel groove 225, so that the positioning in the direction can be completed, through the structural arrangement, an acceptance control system can quickly and accurately determine the positions of the front wheels and the rear wheels, the positioning in the front and rear direction is carried out, so that the automatic positioning effect of automatic adjustment and adaptation is achieved, and after the detection is finished, all the descending bearing steel beams 221 are driven to ascend and reset to be flat with the horizontal plane through the action of the support driving cylinder 222 The table 21 is flush for easy ejection.

The parking pointing device 23 is used for positioning the vehicle in the left-right direction, and the final positioning in this direction is the final positioning position of the vehicle, and the parking position for detection includes a rear wheel pointing adjustment device 231 and a front wheel pointing adjustment device 232, where the rear wheel is usually two wheels, in this embodiment, the rear wheel pointing adjustment device 231 is respectively disposed at two ends of the rear wheel positioning section groove 212, and includes a rear wheel moving push block 2311 and a rear wheel push block drive 2312, the rear wheel moving push block 2311 is a rectangular block as illustrated in the figure, and is disposed on the upper surface of the horizontal platform 21 and vertically crosses the rear wheel positioning section groove 212, the rear wheel push block drive 2312 is disposed outside the end of the rear wheel positioning section groove 212 and is connected to the rear wheel moving push block 2311 for driving the rear wheel moving push block to move, the rear wheel moving push block 2311 is provided with a rear wheel push block guide structure 2313 so that the rear wheel moving push block 2311 can move smoothly, when the rear wheel moving push block 2311 works, the side face of the rear wheel moving push block 2311 is in contact with the corresponding outer side face of the rear wheel, so that the rear wheel is pushed to move left and right, and when the two rear wheels are pushed and clamped by the two rear wheel moving push blocks 2311 according to the setting, the rear wheel moving push block is the fixed point position.

Since the front wheels of the vehicle have two cases, one wheel and two wheels, the present embodiment discloses that the two front wheel set point adjusting devices 232 are actually disposed according to the needs, and may be disposed in both cases or only one case. First, as shown in the figure, the front wheel fixed point adjusting device 232 is disposed at two ends of the front wheel positioning section groove 211, and includes a front wheel moving push block 2321 and a front wheel push block drive 2322, the front wheel moving push block 2321 is disposed on the upper surface of the horizontal platform 21 and vertically crosses the front wheel positioning section groove 211, the front wheel push block drive 2322 is disposed outside an end of the front wheel positioning section groove 211 and is connected to the front wheel moving push block 2321 for driving the front wheel moving push block to move, the front wheel moving push block 2321 is provided with a front wheel push block guiding structure 2323, the structure is the same as the structure of the rear wheel fixed point adjusting device 231, and is suitable for adjusting the front wheel of a vehicle whose front wheel is two wheels, and the action and the using principle are the same, and are not repeated herein. Secondly, the front wheel fixed point adjusting devices 232 are symmetrically arranged on both sides of the middle point of the front wheel positioning section groove, as shown in the figure, the front wheel fixed point adjusting devices 232 comprise a T-shaped moving push block 2324, a T-shaped push block drive 2325 and a T-shaped push block guide structure 2326, the cut-off surface of the T-shaped moving push block 234 is in a T shape, the T-shaped moving push block is arranged on the upper surface of the horizontal platform 21 and vertically crosses the front wheel positioning section groove 211, sliding grooves 2327 are respectively arranged on both sides of the front wheel positioning section groove 211, two ends of a T-shaped vertical arm of the T-shaped moving push block 2324 are respectively provided with a connecting rod 2328 embedded into the corresponding sliding groove 2327, a mounting cavity is arranged in the sliding groove 2327, the T-shaped push block drive 2325 are respectively arranged in the mounting cavity of the sliding groove and connected with the connecting rod 2328 for driving the movement, the T-shaped push block guide structure 2326 is arranged between the connecting rod 2328 and the sliding groove 2327, the action of the front wheel fixed point adjusting devices 232 is the same as the principle of the former, however, such a structure can realize adjustment of the front wheel in two directions, when the front wheel is a one-wheel vehicle, the front wheel is between the two T-shaped moving push blocks 2324, so that during adjustment, the two T-shaped moving push blocks 2324 move to clamp the front wheel, that is, to complete the positioning of the front road, and when the front wheel is a two-wheel vehicle, the two T-shaped moving push blocks 2324 move away from each other, and move to be close to the inner side surface of the front wheel on the corresponding side, that is, to complete the adjustment of the front wheel.

The rear wheel set point adjusting device 231 and the front wheel set point adjusting device 232 are driven by a driving force which can achieve a good driving force to move the vehicle at the same time, and the detection of the resetting of the rear wheel set point adjusting device 231 and the front wheel set point adjusting device 232 is finished.

The use method of the offline acceptance workshop of the multi-line laser radar automatic driving equipment is characterized by comprising the following steps of:

firstly, initially, the off-line acceptance workshop is in an initial state, the automatic driving equipment 100 enters from the entrance and the exit and is parked on the acceptance parking platform 2, and during parking, the acceptance detection device 4 at one side of the front end of the automatic driving equipment 100 opposite to the entrance 11 and the front wheels and the rear wheels of the automatic driving equipment 100 are respectively and correspondingly arranged on the parking positioning device 22;

secondly, controlling the parking positioning device 22 to act so that the front wheels and the rear wheels are positioned in the front-rear direction and can not move forward or backward;

thirdly, controlling the parking positioning device 23 to act to adjust the front wheels and the rear wheels to the fixed positions on the parking positioning device 22 and fix the front wheels and the rear wheels;

starting scanning work of the multi-line laser radar 101 on the automatic driving equipment 100, wherein the scanning work comprises the steps of carrying out laser scanning on a plurality of scanning benchmarks by the multi-line laser radar and generating installation detection laser scanning data, and starting the movable trolley to move according to a set moving speed, carrying out laser scanning on the multi-line laser radar simultaneously and generating functional detection laser scanning data;

fifthly, acquiring installation detection laser scanning data and function detection laser scanning data by the acceptance control system to perform data processing analysis judgment, wherein the processing analysis judgment comprises frequency judgment, cluster judgment, level judgment and orientation judgment;

and sixthly, after the detection is finished, controlling the parking positioning device 22 and the parking positioning device 23 to reset, and moving the automatic driving equipment 100 out of the acceptance parking platform. And for the condition that the off-line acceptance check is not passed, the technical personnel performs corresponding processing of the multi-line laser radar according to unqualified judgment data given by the acceptance control system, such as the processing of replacement, parameter adjustment, installation adjustment and the like of the multi-line laser radar, and returns to the steps to perform laser scanning detection again after the processing is completed.

The above embodiments and drawings are not intended to limit the form and style of the present invention, and any suitable changes or modifications made by those skilled in the art should not be construed as departing from the scope of the present invention.

Claims

1. An acceptance parking platform of an off-line acceptance workshop of automatic driving equipment is characterized by comprising a horizontal platform for bearing the automatic driving equipment, a parking positioning device for automatically adjusting the forward parking position of the automatic driving equipment and a parking positioning device for automatically adjusting the tire positioning position of the automatic driving equipment, a front wheel positioning section groove and a rear wheel positioning section groove are transversely arranged on the horizontal platform, the parking positioning device is respectively arranged in the front wheel positioning section groove and the rear wheel positioning section groove, the parking positioning device comprises a plurality of bearing steel beams which are arranged and filled in the front wheel positioning section groove or the rear wheel positioning section groove, a supporting driving cylinder which is respectively arranged at the bottom of each bearing steel beam and a guide structure which is respectively arranged at the two ends of each bearing steel beam, the bearing steel beams can enable the upper surfaces of the bearing steel beams to be flush with the upper surface of the horizontal platform or the upper surfaces of the bearing steel beams to form staggered and concave wheel grooves under the driving support of the supporting driving cylinder.

2. The acceptance parking platform of an off-line acceptance workshop for automatic driving equipment according to claim 1, wherein the bearing steel beam is provided with a pressure sensor.

3. The acceptance parking platform for the acceptance workshop of the automatic driving equipment according to claim 1 or 2, wherein the parking pointing device comprises a rear wheel pointing adjustment device and a front wheel pointing adjustment device, the rear wheel pointing adjustment device is respectively arranged corresponding to two ends of the rear wheel positioning section groove and comprises a rear wheel moving push block and a rear wheel push block drive, the rear wheel moving push block is arranged on the upper surface of the horizontal platform and vertically crosses the rear wheel positioning section groove, the rear wheel push block drive is arranged outside the end part of the rear wheel positioning section groove and is connected with the rear wheel moving push block for driving the rear wheel moving push block to move, and a rear wheel push block guide structure is arranged on the rear wheel moving push block.

4. The checking and parking platform for the offline checking and accepting workshop of the automatic driving equipment as claimed in claim 3, wherein said front wheel fixed point adjusting device is respectively disposed at two ends of the front wheel positioning section slot, and comprises a front wheel moving pushing block and a front wheel pushing block driving, said front wheel moving pushing block is disposed on the upper surface of the horizontal platform and vertically crosses the front wheel positioning section slot, said front wheel pushing block driving is disposed outside the end of the front wheel positioning section slot and is connected with the front wheel moving pushing block for driving the front wheel moving pushing block to move, and said front wheel moving pushing block is provided with a front wheel pushing block guiding structure.

5. The acceptance parking platform of the acceptance workshop for the automatic driving equipment according to claim 3, wherein the front wheel fixed point adjusting device is symmetrically arranged on both sides of the middle point of the front wheel positioning section groove and comprises a T-shaped movable push block, a T-shaped push block drive and a T-shaped push block guide structure, the T-shaped movable push block is in a T shape for the cut-off surface, is arranged on the upper surface of the horizontal platform and vertically crosses the front wheel positioning section groove, sliding grooves are respectively formed on two side edges of the front wheel positioning section groove, two ends of a T-shaped vertical arm of the T-shaped movable push block are respectively provided with a connecting rod to be embedded into the corresponding sliding grooves, the T-shaped push block drives are respectively arranged in the sliding grooves and connected with the connecting rod for driving the T-shaped push block to move, and the T-shaped push block guide structure is arranged between the connecting rod and the sliding grooves.

6. The acceptance parking platform of an off-line acceptance shop of an autopilot equipment according to claim 4, it is characterized in that the front wheel fixed point adjusting device also comprises a second front wheel fixed point adjusting device which is symmetrically arranged at the two sides of the middle point of the front wheel positioning section groove, which comprises a T-shaped movable push block, a T-shaped push block driver and a T-shaped push block guide structure, wherein the section of the T-shaped movable push block is in a T shape, which is arranged on the upper surface of a horizontal platform and vertically strides over a front wheel positioning section groove, two side edges of the front wheel positioning section groove are respectively provided with a sliding groove, two ends of the T-shaped vertical arm of the T-shaped movable push block are respectively provided with a connecting rod which is embedded in the corresponding sliding groove, the T-shaped push block driving device is arranged in the sliding grooves respectively and connected with the connecting rod to drive the T-shaped push block to move, and the T-shaped push block guiding structure is arranged between the connecting rod and the sliding grooves.