CN212875734U

CN212875734U - Solar photovoltaic power generation board cleaning vehicle

Info

Publication number: CN212875734U
Application number: CN202021957760.9U
Authority: CN
Inventors: 李文华
Original assignee: Ningxia Xinhui Electronic Technology Co ltd
Current assignee: Ningxia Xinhui Electronic Technology Co ltd
Priority date: 2020-09-09
Filing date: 2020-09-09
Publication date: 2021-04-02
Anticipated expiration: 2030-09-09

Abstract

The utility model relates to a solar photovoltaic electricity generation board cleaning cart. Including photovoltaic board support (1), this photovoltaic board support (1) includes relative photovoltaic board upper bracket and photovoltaic board lower carriage, and its characteristics are: the photovoltaic panel upper bracket upper surface and photovoltaic panel lower carriage upper surface install a crawler unit respectively, through two cleaning cart crossbeams (8) fixed connection between these two crawler units, still include clean unit, this clean unit both ends are connected with two crawler unit transmission respectively. The beneficial effects of the utility model reside in that: 1. after settling the cleaning cart on the photovoltaic board, only need press the start button, the cleaning operation of whole row photovoltaic board can be accomplished automatically to this cleaning cart. 2. Adopt crawler-type running gear, make the track align the border of photovoltaic board installing support through stop device, can not oppress the photovoltaic board.

Description

Solar photovoltaic power generation board cleaning vehicle

Technical Field

The utility model relates to a solar photovoltaic electricity generation board cleaning cart.

Background

At present, the proportion of clean energy in an energy supply structure is increased year by year, wherein solar photovoltaic power generation is a main source of modern clean energy and is widely applied to the provinces with sufficient sunshine in the middle and western parts at present. However, the natural environment of the middle and western regions is worse, the wind and sand are large, and the photovoltaic panel is often covered by the sand dust, so that the power generation efficiency is influenced. The current industry generally adopts the mode of hiring manpower to use mops for cleaning. This approach has several drawbacks: 1. the operation field is generally in the field, the environment is severe, high temperature, sand wind and the like are very unfavorable for the operation of workers, and therefore the labor cost is high. 2. The manual cleaning has the conditions of non-standard operation, different cleaning standards and incapability of cleaning dead corners, and brings challenges to the cleaning quality control.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a low-cost, high solar photovoltaic electricity generation board cleaning cart of flexibility.

The utility model provides a solar photovoltaic power generation board cleaning cart, includes the photovoltaic board support, and this photovoltaic board support includes relative photovoltaic board upper bracket and photovoltaic board lower carriage, and its characterized in that: the photovoltaic panel upper bracket upper surface and photovoltaic panel lower carriage upper surface install a crawler unit respectively, through two cleaning cart crossbeam fixed connection between these two crawler units, still include clean unit, this clean unit both ends are connected with two crawler unit transmission respectively.

The crawler traveling unit comprises a crawler mounting frame, wherein a crawler loading wheel is mounted at the bottom of the middle of the crawler mounting frame, crawler driving wheels are respectively mounted at two ends of the crawler mounting frame, the crawler driving wheels are in transmission connection with a driving motor, and annular crawlers are mounted on the crawler loading wheel and the crawler driving wheels; and the outer sides of the two ends of the crawler mounting frame are respectively provided with a crawler limiting wheel, and the surface of the crawler limiting wheel is in rolling contact with the outer side surface of the photovoltaic panel bracket.

The cleaning unit comprises three cleaning roller component round pipes bundled together by a cleaning roller clamp, cleaning materials are arranged among the three cleaning roller component round pipes, one end of each bundled cleaning roller component round pipe is in transmission connection with a cleaning roller driving motor, the other end of each bundled cleaning roller component round pipe is arranged on the crawler traveling unit through a bearing, and the cleaning roller driving motor is arranged on a cleaning roller driving motor frame on the crawler traveling unit.

Wherein the cleaning material adopts fabric or sponge; wherein the transmission connection specifically refers to belt transmission.

Wherein, a central control unit is arranged on one crawler unit and is respectively and electrically connected with the cleaning unit and the motors on the two crawler units so as to control the motors to run.

Wherein, two ends of one crawler unit are respectively provided with a distance sensor, the crawler units at two sides of the cleaning unit are respectively provided with a distance sensor, and all the distance sensors are respectively electrically connected with the central control unit.

Wherein, the visual sensor support is respectively arranged between the two cleaning vehicle beams, the visual sensor is arranged on the visual sensor support, and all the visual sensors are respectively and electrically connected with the central control unit.

The beneficial effects of the utility model reside in that: 1. after settling the cleaning cart on the photovoltaic board, only need press the start button, the cleaning operation of whole row photovoltaic board can be accomplished automatically to this cleaning cart. 2. Adopt crawler-type running gear, make the track align the border of photovoltaic board installing support through stop device, can not oppress the photovoltaic board. 3. Adopt novel clean gyro wheel design, this gyro wheel design has low cost, can be according to the characteristics of on-the-spot photovoltaic board installation actual conditions quick adjustment. 4. Adopt four groups of position modules, can accurately distinguish whether the cleaning cart reachs photovoltaic board support border, effectively prevent that the cleaning cart from falling from the photovoltaic board installing support. 5. The cleaning effect of the cleaning surface is monitored in real time by adopting the visual detection of the foreign matters, the foreign matters which are not cleaned are found and reported to the central control system in time, and the position information of the found foreign matters is filed and reported to the data workstation by the central control system, so that the manual retrieval and the secondary cleaning are convenient.

Drawings

FIG. 1 is a schematic structural view of the present invention;

fig. 2 is a flow chart of the present invention.

Detailed Description

As shown in fig. 1, the utility model provides a solar photovoltaic power generation board cleaning cart, including photovoltaic board support 1, this photovoltaic board support 1 is including relative and parallel photovoltaic board upper bracket and photovoltaic board lower carriage photovoltaic board upper bracket upper surface and photovoltaic board lower carriage upper surface install the crawler unit of a linear type respectively, through two cleaning cart crossbeam 8 fixed connection that are parallel to each other between these two crawler units, this crawler unit is perpendicular with cleaning cart crossbeam 8, still includes cleaning unit, and this cleaning unit both ends are connected with two crawler unit transmissions respectively.

The crawler traveling unit comprises a crawler mounting frame 2, a crawler loading wheel 4 is arranged at the bottom of the middle of the crawler mounting frame 2, crawler driving wheels 3 are respectively arranged at two ends of the crawler mounting frame 2, the crawler driving wheels 3 are in transmission connection with a driving motor 7 arranged beside the crawler mounting frame 2, and an annular crawler 6 is arranged on the crawler loading wheel 4 and the crawler driving wheels 3; and the outer sides of the two ends of the crawler mounting frame 2 are respectively provided with a crawler limiting wheel 5, and the surface of the crawler limiting wheel 5 is in rolling contact with the surface of the outer side of the photovoltaic panel bracket 1, so that the crawler walking unit is prevented from being inclined and derailed and the vibration is reduced.

The cleaning unit comprises three cleaning roller component round pipes 10 which are bundled together by a cleaning roller hoop 9 and are in a shape of a Chinese character 'pin', cleaning materials are arranged among the three cleaning roller component round pipes 10, the shaft at one end of each bundled cleaning roller component round pipe 10 is in transmission connection with the output shaft of a cleaning roller driving motor 11, the shaft at the other end of each cleaning roller component round pipe 10 is arranged on the crawler traveling unit through a bearing, and the cleaning roller driving motor 11 is arranged on a cleaning roller driving motor frame 12 on the crawler traveling unit. The cleaning material is made of fabric or sponge, the transmission connection is belt transmission, namely, the shaft at one end of the circular tube 10 of the three cleaning roller assemblies and the output shaft of the driving motor 11 of the cleaning roller assemblies are respectively and fixedly connected with belt wheels, and transmission (belt) belts are arranged on the two belt wheels.

Wherein a central control unit 23 is mounted on one crawler travel unit, the central control unit 23 being electrically connected to the cleaning unit and the two crawler travel units, respectively. Two distance sensors are respectively arranged at two ends of the crawler unit, and a total of 4 distance sensors are also respectively arranged on the crawler units at two sides of the cleaning unit, and all the distance sensors are respectively electrically connected with the central control unit 23. And a vision sensor bracket is respectively arranged between the two cleaning vehicle cross beams 8, a vision sensor is arranged on the vision sensor bracket, and all the vision sensors are respectively and electrically connected with the central control unit 23.

Example 1:

the utility model provides a solar photovoltaic power generation board cleaning cart, including vehicle chassis, this chassis adopts track structure, and two tracks 6 of during operation walk respectively on the upper and lower installation frame of photovoltaic board, guarantee can not press the photovoltaic panel. And a limiting mechanism is arranged on the side surface of each track 6, so that the chassis can move freely on a solar photovoltaic panel mounting frame with a corresponding size and cannot fall off from a photovoltaic panel. And a cleaning module is fixedly arranged on the chassis and is responsible for cleaning the photovoltaic panel. A position detection module is fixedly mounted on the chassis, and the negative perception cleaning trolley can sense whether the cleaning trolley reaches the edge of the photovoltaic panel or not, so that the cleaning trolley is prevented from exceeding the edge of the photovoltaic panel and falling. The chassis is fixedly provided with a foreign matter detection module which is responsible for detecting whether dirt such as bird droppings and the like which are difficult to remove still exists on the cleaned photovoltaic panel and sending a signal to the central control module when detecting the dirt. The chassis is fixedly provided with a central control module which is responsible for uniformly controlling the coordination work of the vehicle chassis, the cleaning module, the position detection module and the foreign matter detection module. Including the data workstation, this data workstation exchanges data through wireless mode and cleaning cart, has the effect of control cleaning cart state, remote control cleaning cart, record cleaning cart working data, and this workstation can dispose in indoor or on the vehicle.

The vehicle-mounted position detection device comprises a vehicle chassis, and is characterized by further comprising a position detection module, wherein the position detection module comprises 8 high-precision low-delay distance sensors fixedly mounted on the vehicle chassis, and every 2 distance sensors are in a group and are respectively used for detecting the overtravel of an upper edge forward position, the overtravel of a lower edge forward position, the overtravel of an upper edge reverse position and the overtravel of a lower edge reverse position.

Wherein the cleaning module comprises a cleaning roller and a cleaning motor. The cleaning roller is formed by rapidly lapping industrial standard parts, so that the complex process of the traditional cleaning roller die sinking design is avoided, and the effects of high flexibility, large refitting potential and low cost are achieved. Due to the limitation of specific geographical environment, the installation process of the solar photovoltaic power generation panel used at present has no unified standard, the sizes of the installation sites of the photovoltaic panels are different, and the cleaning roller can be rapidly adjusted according to the installation condition of the photovoltaic panels on the site, so that the cleaning roller is particularly suitable for various solar cleaning equipment.

Wherein the foreign matter detection module comprises two monocular vision detection cameras, and two vision modules are respectively adjusted well the preceding of cleaning cart and backward, and when the cleaning cart forward operation, the vision module of adjusting well backward is responsible for detecting and has or not remain the dirt after the cleanness, and when the cleaning cart reverse operation, is responsible for detecting and has or not remain the dirt after the cleanness to the vision module of adjusting well forward. When residual dirt is detected, a signal is sent to a central control system.

The vehicle chassis cleaning device comprises a central control unit 23, wherein the control unit comprises a main control board with a microcontroller, and the main control board is respectively and electrically connected with a human-computer interface, a vehicle chassis walking device, a cleaning module, a position detection module and a foreign matter detection module.

The cleaning vehicle comprises a data workstation, wherein the data workstation exchanges data with the cleaning vehicle in a wireless mode, has the functions of monitoring the state of the cleaning vehicle, remotely controlling the cleaning vehicle and recording the working data of the cleaning vehicle, and can be deployed indoors or on vehicles.

Example 2:

the utility model relates to a solar photovoltaic electricity generation board cleaning cart provides a solar photovoltaic electricity generation board cleaning system with low cost and high flexibility.

1. Including data workstation and cleaning cart, this cleaning cart is at the uniform velocity on photovoltaic board support 1 gos forward, and fixed mounting has clean module on this cleaning cart, and this clean module comprises clean gyro wheel, clean motor, and the brush and the laminating of photovoltaic board of clean gyro wheel, at the cleaning cart in-process that gos forward, clean motor passes through belt transmission and drives clean gyro wheel high-speed rotatory to reach the effect of clean solar photovoltaic board. When the cleaning vehicle starts from one end of the photovoltaic panel and continuously travels to the other end, one-time cleaning operation on the whole row of photovoltaic panels can be completed. If the cleaning is needed to be continued, the cleaning vehicle travels reversely, the cleaning roller rotates reversely, the cleaning vehicle returns to the starting end from the other end to finish the second cleaning, and the cleaning process can be set in advance according to the requirement to determine the cleaning times.

2. Install position detection module on the cleaning cart, this position detection module includes 8 high accuracy low delay distance sensor of fixed mounting on the cleaning cart chassis, and distance sensor installs towards the photovoltaic board, and real-time supervision is to the distance of photovoltaic board, when the distance surpassed the setting value, judges that the sensor is unsettled. Every 2 distance sensors are in a group and are respectively used for detecting the overtravel of the upper edge forward position, the overtravel of the lower edge forward position, the overtravel of the upper edge reverse position and the overtravel of the lower edge reverse position. The specific implementation process is as follows: taking the forward walking of the cleaning vehicle as an example, at the moment, two groups of distance sensors installed at the front part of the vehicle work, the two groups of sensors are respectively positioned at the upper part and the lower part of the cleaning vehicle, each group of sensors consists of 2 distance sensors, and the distance sensors are respectively installed at the front part of the lower edge of the cleaning vehicle and the middle part of the lower edge of the cleaning vehicle, and are close to the front. For convenience of description, four sensors are named as lower front, lower middle, upper front and upper middle. When the sensor is measured to be suspended, the state of the upper front sensor is read at the same time, if the upper front sensor is also suspended, the front end of the cleaning vehicle is judged to be suspended, and because the cleaning roller is arranged in the middle of the cleaning vehicle, the cleaning vehicle needs to continue to move forward for ensuring cleaning without dead angles, when the upper middle sensor and the lower middle sensor are also detected to be suspended, the cleaning vehicle is judged to be nearly half suspended, and the cleaning roller completes the cleaning task of all the areas of the photovoltaic panel. And then the vehicle can be stopped or the secondary cleaning can be carried out reversely. The logic of position detection in the reverse cleaning process is the same as that in the forward direction, except that four distance sensors at the rear of the cleaning vehicle are used, and the details are not repeated herein.

3. Install foreign matter detection module on the cleaning cart, this detection module includes two monocular vision recognition sensors, and the concrete implementation process is as follows: when the cleaning vehicle forwards moves, the vision module arranged at the rear part works to detect whether uncleaned dirt exists on the cleaned solar panel, if yes, the vision module sends a marking signal to the main control, and the main control records the position information when the signal occurs and uploads the position information to the data station for storage. When the cleaning vehicle moves forward in the reverse direction, the vision module installed at the front part works, and the working logic is similar to that when the cleaning vehicle moves forward.

4. The cleaning vehicle is provided with a central control unit 23 which comprises a main control panel with a microcontroller, and the main control panel is respectively and electrically connected with a human-computer interface, a vehicle chassis walking device, a cleaning module, a position detection module and a foreign matter detection module. The control unit receives the data station command, starts the cleaning vehicle operation, receives the sensor signals of the position detection module and the foreign matter detection module during the period, and executes the logic functions as described in embodiment mode 2 and embodiment mode 3 according to the program setting.

5. The system also comprises a data workstation, wherein an operator can issue a working instruction to the cleaning vehicle through the data workstation, and meanwhile, the data workstation continuously receives working parameters returned by the cleaning vehicle, and the working parameters mainly comprise cleaning vehicle speed information, position information, battery residual capacity condition, abnormal alarm information and coordinate information of foreign matters which are not removed.

The present invention is further illustrated by way of the following examples, which are not intended to limit the scope of the invention.

Example 3:

the utility model provides a welding system of flange straight tube, including photovoltaic board support 1, track mounting bracket 2, track drive wheel 3, track bogie wheel 4, track spacing wheel 5, track 6, driving motor 7, cleaning cart crossbeam 8, clean gyro wheel clamp 9, clean gyro wheel subassembly pipe 10, clean gyro wheel driving motor 11, clean gyro wheel driving motor frame 12, clean gyro wheel driving belt 13, clean gyro wheel drive wheel 14, first to fourth distance sensor 15, 16, 17, 18, first to second vision sensor support 16, 21, first to second vision sensor 20, 22 and central control unit 23 based on 32 embedded system.

The photovoltaic panel support 1 is the object of the system. The cleaning vehicle is fixed on the bracket and moves forwards or backwards along the edge of the bracket.

The crawler mounting frame 2 is a core component of a cleaning vehicle travelling mechanism, and the crawler driving wheel 3, the crawler loading wheel 4, the crawler limiting wheel 5, the crawler 6 and the driving motor 7 are all arranged on the crawler mounting frame 2; all 4 driving motor 7 are installed on track mounting bracket 2, all 4 track drive wheel 3 overlap respectively on 4 driving motor 7's output shaft, track 6 is installed by track drive wheel 3, the loop configuration outside that track bogie 4 together formed, track 6 is rotatory together when driving motor 7 is rotatory, track bogie 4 also rotates along with track 6 as follower, the cleaning cart can be forward or backward motion this moment, can not break away from photovoltaic board support 1 in order to guarantee the cleaning cart motion process, the spacing wheel 5 of track has been increased, spacing wheel 5 has guaranteed that the cleaning cart can not rock about the motion process.

The cleaning trolley beam 8 is used for connecting the upper crawler belt 6 and the lower crawler belt 6 and is a main structural member of the cleaning trolley, the cleaning trolley beam 8 is manufactured by adopting a sheet metal process, and 3 times of structural bending is performed for ensuring the structural strength of the cleaning trolley beam.

Clean wheel components pipe 10 is the main component part of clean gyro wheel, this clean gyro wheel comprises three clean wheel components pipe 10, the terminal surface of whole 3 clean wheel components pipe 10 aligns, two liang tangents of disc, last reuse 2 clean gyro wheel clamps 9 with 3 clean wheel components pipe 10 firm bundles together, fill in the mutual tangent plane gap of 3 clean wheel components pipe 10 with the cotton strip of clean usefulness before tying up, clean gyro wheel clamp 9 chucking back cotton strip is also firmly installed. The both ends of cleaning roller are installed respectively on two upper and lower track mounting brackets 2, and epaxial cleaning roller drive wheel 14 of installing of cleaning roller one end, and cleaning roller drive wheel 14 passes through cleaning roller driving belt 13 and installs the output shaft of the cleaning roller driving motor 11 on cleaning roller driving motor frame 12, just can drive cleaning roller together rotatory when cleaning roller driving motor 11 is rotatory, reaches the purpose of clean photovoltaic board support 1.

The first to fourth distance sensors 15, 16, 17, 18 are used to determine the relative position of the cleaning vehicle and the photovoltaic panel support 1, the first to second distance sensors 15, 16 are a set for position measurement when the cleaning vehicle is moving in the forward direction, and the third to fourth distance sensors 17, 18 are a set for position measurement when the cleaning vehicle is moving in the reverse direction. When the cleaning vehicle advances and reaches the edge of the photovoltaic panel bracket 1, the first distance sensor 15 firstly detects suspension, the central control unit 23 controls the driving motor 7 to advance slowly, when the second distance sensor 16 also detects suspension, it indicates that the cleaning roller in the middle of the cleaning vehicle is close to the edge of the photovoltaic panel bracket 1, and the central control unit 23 controls the driving motor 7 to stop and waits for the next instruction.

The first to second visual sensor supports 16, 21 and the first to second visual sensors 20, 22 are used for detecting whether uncleaned dirt remains on the surface of the cleaned photovoltaic panel support 1, the first visual sensor 20 works when the cleaning vehicle moves forward, a foreign matter detection signal is sent to the central control unit 23 when foreign matter is found, the second visual sensor 22 works when the cleaning vehicle moves backward, and a foreign matter detection signal is sent to the central control unit 23 when foreign matter is found.

The central control unit 23 is responsible for monitoring and controlling the working states of the walking module, the cleaning module, the position detection module and the foreign matter detection module, and is also responsible for receiving a control instruction sent by the data station and reporting the working state of the cleaning vehicle to the data station.

The utility model discloses the application method and the theory of operation of device are:

place the cleaning cart in photovoltaic board support 1 top, with spacing round card in photovoltaic board support 1 side, open the equipment power, press the start key, the cleaning cart begins to move forward and clean the gyro wheel high-speed rotation simultaneously, begins clean photovoltaic board surface, along with the cleaning cart constantly gos forward, and a whole row of photovoltaic board obtains cleanly. When the distance sensor at the most front end detects suspension, the front end of the cleaning vehicle reaches the edge of the photovoltaic panel, the advancing speed of the cleaning vehicle is reduced to one third of the original speed, the cleaning vehicle continues to advance, when the distance sensor at the middle part also detects suspension, the cleaning vehicle completes a cleaning task at the moment, the cleaning vehicle stops in place to wait for a further instruction, if secondary cleaning is needed, the cleaning vehicle starts to move reversely, meanwhile, the cleaning roller rotates reversely-to-reverse, secondary cleaning is started, and the detection mode and the execution action of the edge of the photovoltaic panel are the same as those of the primary cleaning. The visual module monitors the working face at any time in the cleaning process, if dirt which is not cleaned exists, the visual module reports information to the central processing unit, the central processing unit records the position coordinates of the cleaning vehicle at the moment and reports the information to the data station, a worker can adjust the recorded information of the data station, manual intervention is implemented aiming at the incomplete cleaning task of the cleaning vehicle, and stubborn dirt which cannot be removed by the cleaning vehicle is removed.

Although specific embodiments of the present invention have been described above, it will be understood by those skilled in the art that this is by way of example only and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.

Claims

1. The utility model provides a solar photovoltaic power generation board cleaning cart, includes photovoltaic board support (1), this photovoltaic board support (1) includes relative photovoltaic board upper bracket and photovoltaic board lower carriage, its characterized in that: the photovoltaic panel upper bracket upper surface and photovoltaic panel lower carriage upper surface install a crawler unit respectively, through two cleaning cart crossbeams (8) fixed connection between these two crawler units, still include clean unit, this clean unit both ends are connected with two crawler unit transmission respectively.

2. The solar photovoltaic panel cleaning cart of claim 1, wherein: the crawler belt walking unit comprises a crawler belt mounting frame (2), crawler belt loading wheels (4) are mounted at the bottom of the middle of the crawler belt mounting frame (2), crawler belt driving wheels (3) are mounted at two ends of the crawler belt mounting frame (2) respectively, the crawler belt driving wheels (3) are in transmission connection with a driving motor (7), and annular crawler belts (6) are mounted on the crawler belt loading wheels (4) and the crawler belt driving wheels (3); and the outer sides of the two ends of the crawler mounting frame (2) are respectively provided with a crawler limiting wheel (5), and the surface of the crawler limiting wheel (5) is in rolling contact with the outer side surface of the photovoltaic panel bracket (1).

3. The solar photovoltaic panel cleaning cart of claim 1, wherein: the cleaning unit comprises three cleaning roller component round pipes (10) bundled together by a cleaning roller hoop (9), cleaning materials are arranged among the three cleaning roller component round pipes (10), one ends of the three cleaning roller component round pipes (10) bundled together are in transmission connection with a cleaning roller driving motor (11), the other ends of the three cleaning roller component round pipes are arranged on the crawler traveling unit through bearings, and the cleaning roller driving motor (11) is arranged on a cleaning roller driving motor frame (12) on the crawler traveling unit.

4. The solar photovoltaic panel cleaning cart of claim 3, wherein: wherein the cleaning material adopts fabric or sponge; wherein the transmission connection specifically refers to belt transmission.

5. The solar photovoltaic panel cleaning cart of any one of claims 1 to 4, wherein: wherein a central control unit (23) is mounted on one crawler unit, the central control unit (23) being electrically connected to the cleaning unit and the two crawler units, respectively.

6. The solar photovoltaic panel cleaning cart of claim 5, wherein: wherein, two ends of one crawler unit are respectively provided with a distance sensor, the crawler units at two sides of the cleaning unit are also respectively provided with a distance sensor, and all the distance sensors are respectively and electrically connected with the central control unit (23).

7. The solar photovoltaic panel cleaning cart of claim 5, wherein: wherein, a visual sensor bracket is respectively arranged between the two cleaning vehicle beams (8), a visual sensor is arranged on the visual sensor bracket, and all the visual sensors are respectively and electrically connected with the central control unit (23).