Mujin Corp
220134 - Operation Manual
Walmart RDC 6063
3400 39 Ave NE
Calgary, AB T1Y 7J4
Canada
Table of Contents
Glossary of Terms, Abbreviations, Acronyms. 7
2.12. Inbound – Outbound Station (IBOB) 20
2.12.2. Control Push Button Station. 22
4.1. Material To Be Handled (MTBH) 28
5.3.1. To open the door interlock. 40
5.3.2. To close the door interlock. 41
iii. Cancel All AMR Actions. 63
6.4.4. Pallet Stacker Screen. 64
6.4.5. Inbound-Outbound Station Screen. 65
6.4.7. Warehouse Inventory Page. 67
ii. Slipsheet Bin Management 69
6.4.8. Inbound Outbound History Page. 71
i. Downloading Statistic Page. 72
6.6. Replacing the slip sheet bin. 75
6.7. Using the pallet stacker 76
7. Basic troubleshooting guidelines. 77
7.1. Case Conveyor Jam Intervention. 77
7.3. AMR stuck in IBOB below Area Scanner 80
7.5. AMR Rack Delocalization. 84
Revision
Revision | Date | Name | Comments |
V1 | 12/12/2023 | Aditya Ranawat |
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Glossary of Terms, Abbreviations, Acronyms
AMR | Autonomous Mobile Robot |
Cell | Subsystem/component |
Container | Pallet, conveyor, etc. |
DC | Destination container |
Destination | Place container for robot |
E-stop | Emergency Stop |
HMI | Human Machine Interface |
IBOB | Inbound-Outbound Station |
LED | Light Emitting Diode |
LOTO | Lockout-Tagout |
MHE | Material Handling Equipment |
PCP | Primary Control Panel |
PDP | Power Distribution Panel |
RCP | Robot Control Panel |
SC | Source container |
SKU | Stock Keeping Unit |
Source | Picking container for robot |
Mujin Corp is providing a robotic depalletization system to Walmart. Pallet loads (single/multi-SKU) will be introduced in the system by an operator and the robotic system will depalletize the load onto the Walmart’s existing X-line conveyor. This manual provides an overview of the Mujin depalletizing system.
System Overview[AR3]
This depalletizing system is composed of three separate robot cells, along with two inbound/outbound stations, a fleet of six AMRs (Autonomous Mobile Robot)[AR4] , and two AMR chargers. Each robot cell features a robot arm equipped with a gripper, which is responsible for picking up and placing the workpieces onto a case conveyor. Within each Robot cell, the system is equipped with two vision systems. This system is tasked with detecting workpieces positioned on the pallets.
To facilitate the system's operation, an operator is involved. The operator's role encompasses the task of bringing in full pallets and removing empty ones through the inbound and outbound station. This station serves as a central hub for the exchange of pallets, enabling a seamless and efficient operation of the entire depalletizing system.[XZ5] [JS6] [XZ7]
Figure 1: Layout Overview
Have a glossary, index, abbreviation list [AR1]
Technical requirements needs to be mentioned that the customer have to satisfy [AR2]
Have one section for Equipment/part description [AR3]
And another for system overview specific to the project
Use abbreviation fullform only once [AR4]
@Aditya Ranawat put in screenshot of whole cell [XZ5]
Just list system composition. We don't need ellaboration. That happens in the subsections below. [JS6]
I believe a general workflow is needed [XZ7]
One page for entire system [AR8]
Robot arm
Figure 2: Yaskawa GP 180-120
Item | Specifications |
Manufacturer | Yaskawa |
Model | GP180-120 |
Arm Reach | Horizontal: 3058 mm (120”) Vertical: 4105mm (162”) |
Payload | 120 kg (265 lbs.) |
Controller Model | YRC1000 |
The robot system is equipped with a Yaskawa GP 180-120L robot arm, featuring six degrees of freedom, allowing it to move in multiple directions and perform complex tasks with precision. The robot is designed to depalletize material and is controlled by the Mujin Controller. To ensure proper functionality and longevity, it is recommended to follow the manufacturer’s instructions for maintenance, lubrication, cleaning, and wearable part replacement (Refer to Maintenance and Troubleshooting Manual).
Gripper
Figure 3: Mujin Gripper
Item | Specifications |
Manufacturer | Mujin |
Model | Mujin Depalletizing Gripper |
Size (L x W x H) | 530mm (21”) x 500mm (20”) x 470mm (19”) |
Weight | 75 kg (165 lbs.) |
With/Without Force Toques Sensor | With Force Torque Sensor |
Number of channels | 63 channels (9 x 7 configuration) |
Each robot system is equipped with a Mujin gripper, a 63-channel gripper that generates vacuum through a blower. It is designed to handle and manipulate parts within the robot cell.
To ensure ideal performance of the gripper, air supply with a pressure of 0.6 MPa and vacuum of at least -65 kPa to -75 kPa is needed. The air pressure is found at the pressure meter on the robot's riser and the vacuum reading on the side of the gripper.
To ensure optimal performance and longevity of the gripper, it is essential to follow maintenance guidelines and replace worn components as needed (Refer to Maintenance and Troubleshooting Manual).
Dress pack
The dress pack refers to the cabling and protective covering mounted on the robot arm and pedestal that enables the transmission of power, signals, pressure air and vacuum between the end effector and controller/air sources. It is the "wiring harness" of the robot.
The dress pack contains several types of cables, including power cables, signal cables, and pneumatic hoses for the gripper. These cables are organized and protected within the dress pack to prevent tangling, interference, and damage during the robot's movements. It is designed to be flexible, allowing it to move with the robot's joints and rotations. It is constructed with durable materials that can withstand the rigors of industrial environments, including exposure to dust, debris, and mechanical stress.
Item | Specifications |
Manufacturer | Mujin |
Blower
Figure 4: Blower integrated into the Robot Pedestal
Item | Specifications |
Manufacturer | Mujin |
Air supply | 0.6 MPa |
The blower for each robot cell is integrated into the robot pedestal. The blower creates vacuum pressure and suction by a rotating motor fan. This vacuum pressure allows the gripper to handle the packages. The blower also comes with a filter and regulator which keeps the air entering the gripper clean from debris, water, and oil.
Conveyor
Figure 5: Robot cell conveyor
Item | Specifications |
Manufacturer | Russel Conveyor |
Type | MDR Conveyor |
Zone size | 24” |
In each cell, a case conveyor is used to send depalletized material out of the robot cell. The conveyor is designed to integrate with other material handling equipment and includes 13 independent motors.[AR1] [JS2]
Each conveyor utilizes 14 photo eyes an[AR3] [JS4] d 2 distance sensors to monitor the conveyor’s status and track cases placed on it. These sensors ensure smooth and efficient operation by controlling the conveyor’s movements according to the detected conditions.
If the conveyor becomes full, the robot will temporarily pause operations until the destination location (DC1 or DC2) is cleared. Once cleared, the robot will automatically resume normal operation based on the feedback from the photo eye sensors[JS5] .
Figure 6: Robot Destination Locations on the Case Conveyor
Vision System
Figure 7: Vision System
Item | Specifications |
3D Camera | |
Manufacturer | Mujin |
2D Camera | |
Manufacturer | Mujin |
LED Lights | |
Manufacturer | Metaphase |
Each cell has a vision system that gives the robot “eyes.” A 3D camera, a 2d color camera, and Metaphase polarized LEDs work together to identify where cases are in 3d space and to differentiate SKUs from each other. This allows the robots to motion plan and move the gripper to the correct locations.
@Xuanpu Zhang Please confirm, it will be more than 4 for each robot cell [AR1]
[JS2]Confirmed number onsite
@Xuanpu Zhang Same as above. There will be more photoeyes [AR3]
[JS4]Confirmed numbers on site
[JS5]Need a diagram here that is reflective of the calgary case conveyor
Electrical Panel
There are 7 electrical panels throughout the entire system. Each robotic cell has one Robot Control Panel (RCP) and Power Distribution Panel (PDP). The PDP and RCP for each cell work together to control and distribute power across all devices within each work cell.
In addition, there is another panel, the Primary Control Panel (PCP) that powers and controls the rest of the system. All the power transmission and control for the AMR’s, inbound/outbound station, pallet stacker, and various safety scanners is done here.
Figure 8: Panel Locations
Have all pictures in B&W with equipment in color [AR1]
AMR
Figure 9: Geek+ P800
Item | Specifications |
Manufacturer | Geek+ |
Model | P800 |
Payload | 1000kg (2205 lbs.) |
AMRs are responsible for moving pallets around on AMR rack. They are programmed to operate fully autonomously, and the operator should not attempt to change its setting.
There are two parts of AMRs that operator can interact with, the lighting system and buttons/Estops.
AMR Lights
The AMR lights exhibit various colors and flashing patterns to indicate different AMR statuses. The operator should be trained to know signals mentioned below, which are crucial for operating the AMR effectively.
AMR Light Color | State | Description | Intervention needed |
Green | Solid | Robot does not recognize ground QR code | Yes* |
Red | Solid | E-stop triggered, or brake is released | Yes* |
Yellow | Solid | Obstacle detected in AMR path | Remove obstacles. |
Cyan | Solid | Gyroscope calibrating | No |
White | Solid | Robot software upgrading | No |
Blue | Solid | Operational | No |
*For more info and for all other errors/light behavior refer to the Maintenance and Troubleshooting Manual.
AMR Charging Station[XZ1]
Figure 10: AMR Charging Station
Item | Specifications |
Manufacturer | Geek+ |
Model | E4850A |
The charger is designed to replenish the battery of the AMR. It serves as the power source for the AMR's battery system. The charger is equipped with safety features to regulate the charging process and prevent overcharging. It is specifically designed to be compatible with this model of AMR. The operator will not attempt to change its settings [AR2] during normal operations (Refer to the Maintenance and Troubleshooting Manual for more information).
Figure 11: AMR Charging Station Location
AMR Rack
Figure 12: AMR Rack
Item | Specifications |
Manufacturer | Mujin |
Weight | 70kg (154 lbs.) |
The pallet sits on top of the AMR rack. The AMR moves under the rack, lifts it up and carries the pallet around in the system. Each rack has a designated number marked on the side which help in tracking it. This number is also presented on the HMI, if in case the operator wants to eject a particular pallet from the system.
[XZ1]@Aditya Ranawat Please add a screenshot with AGV charging stations highlighted [XZ1]
settings to be mentioned in maintenance [AR2]
Pallet Stacker
Figure 13: Pallet Stacker
Item | Specifications |
Manufacturer | Palomat |
Payload | 500kg (1102 lbs.) |
Maximum Capacity | 15 pallets |
The Pallet Stacker accepts empty pallets from AMR’s that come from the robot cells. Once full, it de-stacks all empty pallets to AMR’s which in turn transfer it to one of the Inbound-Outbound stations.
Figure 14: Pallet Stacker Location
Inbound – Outbound Station[XZ2] (IBOB)
Figure 15: IBOB Assembly
The IBOB serves as the logistical interface within the system. It is the staging area for loaded pallets going in the system; and for empty stacked pallets or ejected pallets going out of the system. It comprises of an internal restricted section and an external user interface to ensure seamless operation.
Within the internal restricted area, AMRs execute pallet drop-offs and pickups. This space is safeguarded by two area scanners, strictly off-limits without adhering to designated safety protocols (See section 5 for more information).
On the external user interface, there are two light bars, and a control station with four push buttons. Here is a breakdown of their functions.
colored box should have less gradient [AR1]
[XZ2]@Xuanpu Zhang screenshot of IBOB design
Strip Light
Figure 16: Strip Light
The strip light provides a visual indicator for the status of the station and visually assist the operators to properly load the pallet on the AMR rack.
# | Strip Light Color | State | Description |
1 | Red | Solid | Zone unavailable to load. |
Red | Solid | ||
Red | Solid | ||
2 | Red | Flashing | Zone has faulted. |
Red | Flashing | ||
Red | Flashing | ||
3 | Blue | Solid | The rack is present and ready to load/pallet needs to be brought forward. |
Green | Flashing | ||
Blue | Solid | ||
4 | Blue | Solid | The pallet has been properly positioned and is ready to move out. |
Green | Solid | ||
Blue | Solid | ||
5 | Blue | Solid | The pallet has overshot and must be brought back towards the operator. |
Yellow | Solid | ||
Blue | Solid | ||
6 | Blue | Solid | The pallet being sent outbound. |
Yellow | Flashing | ||
Blue | Solid |
Control Push Button Station
Figure 17: Control Push Button Station
It facilitates manual input for specific functions. Each button corresponds to a predefined action. The following table describes the function of each button.
Control Push Button Station | Description |
SINGLE SKU | The pallet to be executed will be labeled as single-SKU. The button will illuminate once pressed (Default: multi-SKU). |
HIGH PRIORITY | The pallet to be executed will be labeled as High Priority. The button will illuminate once pressed (Default: Low priority). |
EXECUTE LEFT | The button will illuminate once the pallet is properly loaded. When pressed, this button would execute the left zone in the IBOB. |
EXECUTE RIGHT | The button will illuminate once the pallet is properly loaded. When pressed, this button would execute the right zone in the IBOB. |
Mujin Pendant
The Mujin Pendant is a portable terminal used to operate, control, and program the robot cells. Located in front of the control panel, the pendant can be moved to operate the cell from various positions near the robot cell. It provides a user-friendly [JS1] interface for viewing alarms, making manual movements, starting, and stopping the robot, and performing other day-to-day tasks.
There are 4 Mujin Pendant kept across the system – one near each robot cell to control the respective cell and one near the primary control panel.
Figure 18: Mujin Pendant
lol [JS1]
Figure 18: Mujin Pendant
Enabling Switch
The enabling (deadman) switch on the Mujin Pendant is a crucial safety feature for robot operation in manual or check mode. The switch has three positions: unpressed/released, enabled, and hard press/panicked (OFF-ON-OFF). The robot operates only when the switch is in the enabled position during manual or check mode. The operator must lightly press and hold the switch in the enabled position to allow operation. Releasing or pressing harder disables robot operation, ensuring a quick and safe stop in case of an emergency.
Figure 19: Back of Mujin Pendant
Figure 20: Enabling the Deadman Switch
Mode Selector
The mode selector on the Mujin Pendant is used to choose between different robot operation modes. The selector has three positions: Manual, Check, and Auto
- Manual Mode: Used for manual control of the robot. This mode allows the operator to move the robot using the pendant buttons. The deadman switch must be held in the enabled position to allow movement in manual mode.
- Check Mode: Used for debugging and troubleshooting purposes. The robot will not execute the production cycle, but instead perform a dry run to allow the operator to check the robot’s movement and function.
- Auto Mode: Used for normal operation of the robot cell. In this mode, the robot will execute programmed production cycle and automatically stop if any safety zone is breached or if an E-stop button is pressed.
Mujin Controller
Serving as the central control unit, the Mujin Controller manages and coordinates the actions of the robot, gripper, vision system, conveyor, and all other inputs and outputs within the robot cell. It offers advanced functionality and flexibility for programming and operating the robot, with user-friendly, intuitive interfaces that streamline operation and troubleshooting.
There are 4 Mujin Controllers in the system – one mounted in each robot control panel and one in the primary control panel.
Figure 21: Mujin Controller
System Requirement
Item | Specifications |
Temperature | 0-40°C |
Humidity | 20%-80% (No condensation) |
Lighting | System shall not be exposed to direct sunlight and strong lighting; and the lighting environment shall not change over time. |
Robot Cell Power Supply | 480V, 60A, 3-phase |
Primary Panel Power Supply | 120V, 50A, Single phase |
Pallet Stacker Power Supply | 120V, 10A, Single phase |
AMR Charger Power Supply | 220V, 15A, Single phase |
Robot Air Supply | 80psi, 40cfm |
System Specifications
Material To Be Handled (MTBH)
Workpiece
Item | Specifications |
Workpiece | Case |
SKU Type | Multiple |
Minimum Size (L x W x H) | 9” (229) x 6” (152) x 2” (51) |
Maximum Size (L x W x H) | 42” (1067) x 24” (610) x 32” (813) |
Weight | 2lbs (0.9kg) – 70lbs (32kg) |
Conditions |
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Exceptions | The customer will be responsible for learning to work with the system to understand the limitations of the automation and how to organize from an operational standpoint. The following exceptions apply primarily to the rate and performance of the system. For exception handling, Mujin can have standard workarounds built into the UI as needed. This is up to the customer in most cases as they set up or replicate their existing production process.
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Slipsheet
Item | Specifications |
Workpiece | Corrugated or paperboard slipsheet. |
Size (L x W x H) | 50” (1270) x 50” (1270) |
Conditions | Robot will place slip sheets in the gaylord under these conditions:
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Exceptions |
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Pallet Load
Item | Specifications |
Workpiece | Pallet load |
Max Size (L x W x H) | 48” (1220) x 40” (1016) x 84” (2134) Note: Maximum height includes pallet |
Max weight | 2100lbs (953kg) |
Load Specs |
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Conditions |
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Exceptions | Pallet loads that are deemed non-transferrable and therefore at risk to toppling over while being transported by AMR require manual intervention by the operator. Pallet loads cannot be wrapped by anything that prevents the cases from being picked (all wraps will be removed prior to entering the system). |
Pallet
Item | Specifications |
Workpiece | Pallet |
Size (L x W x H) | 48” (1220) x 40” (1016) x 6.5” (165) |
Weight | Pallet can carry up to 2100lbs (953kg) |
Conditions |
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Exceptions | Pallets with following defects are not to be utilized, as they can cause faulty stacking of empty pallets at the pallet stacker:
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Slipsheet Bin
Item | Specifications |
Workpiece | Slipsheet bin |
Size (L x W x H) | 48” (1220) x 40” (1016) x 36” (914) |
Conditions | Robot will place slip sheets in the slipsheet bin under these conditions. Slipsheet bin conditions:
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Exceptions |
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Safety Overview
Safety Fence[AR1]
A safety fence encloses the robot cell's perimeter to prevent personnel from accessing hazards within the robot cell during operation. The robots and AMRs are programmed to operate exclusively within the safety fencing, and it is vital to keep safety zones clear of personnel during operation. Unauthorized access may lead to severe injury or death. Regularly inspect the safety fencing for condition, and report and repair any damages immediately.
There are several sliding doors in the system to give operators access to enter the cell. Each robot cell has an operator access door for maintenance and troubleshooting each cell individually. The AMR highway has three sliding doors which allow operators as well as forklifts to enter the system for emptying the slip sheet bins, maintenance and troubleshooting. Each IBOB also has an operator access sliding door to clear the station of any fallen packages or debris.
Figure 22: Safety Fence Location
All subsystem to be singular [AR1]
Split in three - safety fence, operator and forktruck access [AR2]
Figure 23: Operator Access Locations
Figure 24: Fork truck Access Locations
Area Scanner
Figure 25: Area Scanner
Item | Specifications |
Manufacturer | Leuze |
Model | RSL450P-S/CU400P-3M12 |
Operating range | 0-3m |
The safety area scanner uses a laser to scan an area to detect a person/object near a hazard. When a person/object is detected, a signal is sent to either reduce the speed or stop the hazard depending on how close the person/object is to the hazard. They act as a virtual fence to divide the system into different zones/areas.
Figure 26: Area Scanner Virtual Fence
The layout employs seven area scanners, each monitoring a zone/area. They are muted for AMRs to access the area. The following scanners act as the virtual fence between the below mentioned areas:
Scanners | Virtual fence between |
IBOB1-SCAN1 | IBOB1 and forklift/operator |
IBOB1-SCAN2 | IBOB1 and AMR Highway |
IBOB2-SCAN1 | IBOB2 and forklift/operator |
IBOB2-SCAN2 | IBOB2 and AMR Highway |
RC1-SCAN1 | Robot Cell 1 and AMR Highway |
RC2-SCAN1 | Robot Cell 2 and AMR Highway |
RC3-SCAN1 | Robot Cell 3 and AMR Highway |
Figure 27: Area Scanner Locations
Door Interlock
Figure 28: Door Interlock
Item | Specifications |
Manufacturer | Fortress |
With/Without Escape release | With Escape release |
At each entryway, there is a safety rated dual channel interlock to prevent operation of machinery when access is needed to the working cells. If the interlock is open, the cell cannot be started.
The door interlock features 4 buttons, a trapped key, and an internal release mechanism to interact with. The following are the functions of each button in their respective subsystem:
BUTTON | FUNCTION |
STOP | Stops robot arm, conveyor, AMR in the cell and don’t allow any other AMRs to enter. |
REQUEST TO ENTER | Gradually stops the respective cell.
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RESET | Resets all faults/errors in the respective cell for that cycle. |
START | Starts production cycle or resumes operation in the respective cell. |
Figure 29: Door Interlock Locations
To open the door interlock
# | Description | Image |
1 | Under normal operation, this is how the door interlock should look |
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2 | When you press “Request to Enter,” the orange light should illuminate on the door interlock |
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3 | Rotate the key counterclockwise until it is perpendicular to the floor. When the key is released, a red light should illuminate on the door interlock |
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4 | Take out the key, lock out the door tongue, and enter the cell |
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To close the door interlock
# | Description | Image |
1 | Close the door and insert the key in the door interlock |
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2 | Rotate the key till the red light is turned off |
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3 | Press “Reset” to engage the lock |
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4 | Press “Start” to start/continue production cycle |
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Stack Light
Figure 30: Stack Light
Item | Specifications |
Manufacturer | Banner |
The stack light serves as a visual beacon, offering immediate insight into the current state of operations for the respective cell.
The stack light also emits a 2Hz siren when there is a fault/error in the respective cell.
Stack Light Color | State | Description |
Red | Solid | Request Operator Intervention |
Flashing | System has faulted | |
Green | Solid | System running |
Flashing | System ready to run | |
Blue | Solid | Operator intervention required (conveyor jam, induct jam, etc.) |
Flashing | Material restock required | |
Yellow | Flashing | AMR/Pallet stacker fault in the respective cell |
The siren can be muted in the following ways:
- Recover the fault and rest the error.
- Opening the door associated with the faulted cell.
- Muting the buzzer for that particular fault/error from the HMI (Section 6.4.1)
E-stop
Figure 31: Mujin Pendant E-stop
Figure 32: Pallet Stacker E-stop
Figure 33: Robot Arm Pendant
The e-stop or emergency stop are used to hard stop the respective components. There are multiple e-stops surrounding[JS1] the cell. The following e-stops show the components that will come to a complete halt when pressed.
E-Stop | Components |
Mujin Pendant | Robot arm, conveyors of the respective cell |
Pallet stacker | Pallet stacker |
Robot Arm Pendant* | Robot arm |
AMR* | AMR |
*WARNING: Should be used by authorized personnel only. Refer to Maintenance & Troubleshooting Manual. |
Figure 34: E-stop Locations
@Aditya Ranawat can you please work with aaron to provide clarity/a map of e-stops and what each of them will do? I know therere was some confusion around which e-stops will cause which equipment to stop and what category those will be [JS1]
Remove e-stops in the cell. Have the e-stops that will be used only by the operator. Others will be in maintenance. [AR2]
Warning Label[JS1]
Warning labels play a critical role in communicating potential hazards associated with operating the robot cell and outlining necessary safety precautions. These labels are strategically placed throughout the system to ensure clear visibility and to serve as a constant reminder to operators and maintenance personnel of potential risks. It is crucial that all personnel working with or around the system familiarize themselves with the warning labels and adhere to the safety precautions they recommend. Regularly inspect the labels for any signs of wear, damage, or fading that may impact its legibility. If a label is damaged or missing, promptly report the issue and replace the label to ensure continuous safety awareness. Some of the warning labels around the system have been mentioned below:
Description | Labels[AR2] |
Robotic Area: Danger sign to protect and caution operators from entering the cell. |
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Not an Entrance: Sign to notify operators not to enter through the opening. |
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Compressed air: Warning sign to caution operators to bleed off air before servicing. |
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Falling material: Danger sign to warn operators of falling material from the pallets. |
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Stay clear of moving conveyors: Sign to caution operators to stay clear of running conveyors. Follow LOTO procedure before servicing or repairs. |
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Pinch point warning: Alerts operators to areas where moving parts may cause crushing or pinching injuries if hands or fingers are caught between them.
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Rotating machinery: Danger sign located around the cell to caution operators of AMR’s rotating. |
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High voltage warning: Indicates that a specific area or component of the robot cell contains electrical hazards that may cause electric shock or electrocution if not properly managed.
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LOTO: Signs located near every device where LOTO procedure is required. |
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In addition to understanding and adhering to the information on warning labels, all personnel should follow the general and robot cell-specific safety guidelines provided in this manual to ensure a safe and efficient working environment.
[JS1]Add pictures for all warning labels mentioned in this
Beginning of the document [AR2]
Lockout-Tagout[AR1]
Lockout-tagout (LOTO) is an essential safety measure that must be followed when servicing or maintaining the Mujin system. LOTO is the process of disconnecting and isolating equipment from its energy source to prevent unexpected start-up or release of energy that could cause harm to personnel.
Before servicing or maintaining the system, the operator must ensure that the equipment is de-energized and cannot be restarted until the maintenance or servicing work is completed. LOTO procedures require locks and tags to prevent the equipment from being accidentally energized or re-energized during maintenance or servicing work.
Figure 35: LOTO for Power Disconnect
Figure 36: Pressure relief valve
The LOTO process for the Mujin system involves[JS2] [JS3] [QG4] the following steps:
- Notify affected personnel: Inform all relevant personnel that maintenance or servicing work is about to take place.
- Shut down the equipment: Follow the shutdown procedure outlined in the manual to cease equipment operation.
- Door interlock lockout: After entering the system through the door, keep the door interlock key on you.
- Disconnect the power sources: Ensure all energy sources are isolated.
There are multiple electrical power disconnects located in the system:- Robot cell: Each robot cell will have a main power disconnect located next to the panel.
- Primary control panel: There will be a disconnect next to it.
- Each PDP in the robot cell has a quick disconnect.
- Each blower panel in the robot cell has a quick disconnect.
- Pallet Stacker: The pallet stacker is powered through the power disconnect located near the pallet stacker.
- AMR chargers: Each AMR charger is powered by a power disconnect located near it.
There are three pressure relief valves installed in each robot cell next to the blower.
- Lock and tag: Lock and tag the equipment to prevent it from being accidentally energized or re-energized during maintenance or servicing work.
- Test the equipment: Confirm the equipment is de-energized and cannot be restarted until the maintenance or servicing work is completed.
- Conduct the maintenance or servicing work: Proceed with the required tasks safely.
Will be done by maintenance [AR1]
[JS2]There's also a procedure for removing gravitational potential energy from the robot… I will look into it further and add
@Aditya Ranawat @Quan (Matthew) Gan there should be something in here about sending robot to maintenance position via the hmi feature that has been discussed. maybe we wait until it has actually been developed [JS3]
For walmart, any AGV control UI features belong to the fleet manager UI which is still under development. We believe we can have it next month. If the fleet manager is not down next month, I'll implement this feature. [QG4]
Figure 37: LOTO locations
By following LOTO procedures, the operator can ensure that the Mujin system is safely maintained or serviced without the risk of unexpected start-up or release of energy that could cause harm to personnel.
Use different shapes. Circle on circle is hard to visualize [AR1]
Operating Procedure
Initial Setup[AR1]
- Visually check that the safety fencing and all areas of the cell are securely installed and there are no obstructions or debris that could interfere.
- Ensure that all robots are in home position and there is no package held by the gripper.
Figure 38: Robot in Home Position
- Verify that the air supply is switched on for each subsystem under operation.
- Ensure that the air supply pressure to the gripper reads 0.6MPa and the vacuum supply reads -65kPa.
Figure 39: Air supply pressure (located near the blower)
Should be under daily operating procedure [AR1]
Figure 40: Vacuum supply pressure (located on the side of the gripper)
- Confirm that the dress pack is not twisted or falling out. Confirm that each joint of IGUS is not decoupling (Refer to Maintenance and Troubleshooting Manual).
- Ensure that all conveyors are empty and have no packages on them.
- Ensure that all panels in the system are powered on.
- Verify that the stack lights indicate the correct status of the respective area that is under operation (See section 5.4).
- Check if the system is free from any warnings/errors through either of the HMI.
Figure 41: HMI showing no error.
- Resolve any errors (Refer to Maintenance and Troubleshooting Manual).
- “Reset” and “Start” entire system (See section 6.4.1).
- To start each cell individually, “Reset Fault” and “Start” system again either through the HMI (See section 6.4) or door interlock (See section 5.3) for each robot cell and the AMR Highway.
Figure 42: HMI showing Robot Cell 1 with Start and Reset Fault highlighted.
Figure 43: IBOB station with empty rack
- The area scanner will mute/unmute from the feedback of the muting photo eyes so that the intentional AMR move in will not trigger area scanner.
- Once the AMR has lowered the rack into position and stopped, a photo eye will verify the rack positioning and begin switching the safety scanner’s muting field for the associated zone. This will disable the field to allow operators to load the rack.
- Once the field has been properly switched, the strip light will indicate that the zone is “ready to load[JS3] ” (See Section 2.12.1).
- The forklift operator will bring a loaded pallet in front of the IBOB area.
- Defoil the pallet (if wrapped); cut all plastic and slipsheet that are overhanging from the pallet load.
- After the pallet is defoiled, the operator will then signal the AMR whether the loaded pallet is multi/single SKU and high/low priority using the push buttons provided at the control station (See section 2.12.2).
- The forklift operator will then move into the inbound location with the loaded pallet lifted at least 20” above the floor.
- As the loaded pallet fully passes over the guard, the forklift operator will lower the pallet down into position.
- Positioning the pallet on the rack
- Left/Right: Using the help of the side metal guards, the operator can side shift and center the pallet on the rack within three inches.
- Front/Back: Photo eyes located on the side metal guards can send a signal when the pallet is centered with the rack. An LED strip mounted on the fence post to provide whether the pallet is “loaded” or “overshoot” (See section 2.12.1).
Figure 44: Operator loading pallet at IBOB.
- Once the positioning is successful, the operator can lower the loaded pallet on the rack.
- Forklift operators can back up and remove the forks from the pallet.
Figure 45: Loaded Inbound pallet at IBOB.
- If the IBOB zone’s safety scanners field is clear and the pallet has been properly positioned, the “Execute Left”/ “Execute Right” button will illuminate.
- The AMR will then be sent out into the AMR Highway to allocate the pallet appropriately.
Outbound Operation
- AMR will move into the IBOB with a rack stacked with empty pallets or ejected loaded pallets in the raised position (Refer to section 6.4.4 & 6.4.7 for more information on removing empty pallets and eject loaded pallets from the system respectively).
- The area scanner will mute/unmute from the feedback of the muting photo eyes.
- Once the AMR has lowered the rack into position and stopped, a photo eye will verify the rack positioning and begin switching the safety scanner’s field to a warning field for the associated zone. This will disable the field to allow operators to unload the rack.
- Once the field has been properly switched, the strip light will indicate that the zone is “pallet sent outbound” (See section 2.12.1).
- Operators will retrieve the loaded pallet and replace it with another that is ready to be sent into the system (Refer to section 6.2 for inbound operation procedure).
[AR1]Confirm operation
Using the HMI
Home Screen
The home page will display the entire system status. The operator can click the subsystem for more details within the respective cell.
Each subsystem has its name and status:
- Robot cell (Robot Cell 1, Robot Cell 2, Robot Cell 3)
- Inbound-Outbound Stations (IBOB 1, IBOB 2)
- Pallet Stacker
- AMR Highway
- Door (Door 1, Door 2, etc.)
- Area Scanner
Figure 46: Home Screen
System Controls
The system control button can be found below the hamburger icon on the home page. This controls the entire system entirely. The operator can “Start”, “Reset” and “Stop” the entire system from these buttons.
Figure 47: System Control Button
Mujin Icon
The operators can click the Mujin icon on the top left to redirect to the home page.
Figure 48: Mujin Icon
Menu (Hamburger icon)
On the top right, the operators can use the drop-down menu to navigate to different pages.
Figure 49: Hamburger Icon (Dropdown Menu)
Buzzer
The buzzer button is located on the top right of the home screen. This button is used to mute the siren from the stack light.
Figure 50: Buzzer button
When the “Buzzer” button is pressed, a “Mute and Acknowledge” popup will be displayed. Select the respective cell to mute that particular stack light or “Mute all” to mute all the stack lights at once.
Figure 51: Mute and Acknowledge popup
Robot cell Screen
On the robot cell page, the operator can use the buttons to “Start” or “Reset Fault.” They need to press and hold the “Unlock” button for 3 seconds to enable the control button.
Figure 52: Robot Cell 1 Screen
AMR System Screen
On the AMR system page, the operators can use the buttons to “Start”, “Reset Fault”, “Stop” and “Request to Enter”. This page will also list all AMRs in our system.
Figure 53: AMR State Screen (List)
| Description |
Robot Name | The AMR name. |
Status | The current AMR state. |
Power | The current AMR power from 0 to 100. |
Is Charging | Indicate if the AMR is charging. |
Frame Name | The name of frame that the AMR is holding or “Empty” if it is not. |
The AMR system page also offers an AMR map view, allowing operators to visually track the real-time positions of the AMRs on a map.
Figure 54: Dropdown for Map and List
Figure 55: AMR State Screen (Map)
Operators can click on the AMR directly on the map to access detailed information about the specific AMR. Click the close button or any other position to close the popup window.
Figure 56: AMR Status window
The AMR Map screen also has a “Move to Buffers” and a “Cancel All AMR Actions” button located on the top right of the page.
Figure 57: Move To Buffers and Cancel All AMR Actions button
Move To Buffers
NOTE: Make sure no zones are in error state. |
Note: This button should be pressed only during maintenance of the AMR’s or to shut them off at the end of the operating hours. |
This feature moves all the AMRs into the buffer locations. After pressing the button, there will be a popup to acknowledge this request.
Figure 58: Popup window to confirm Move To Buffers
Press confirm to start operation of moving the AMRs to the buffer locations.
Cancel All AMR Actions
Note: This button should be pressed only when AMRs are not moving as intended. |
This feature will cancel all the existing actions for the AMRs and reset for new paths.
Figure 59: Popup window to confirm Cancel All AMR Actions
Press confirm to start operation of canceling the existing AMR paths and to rest them.
Pallet Stacker Screen
The user can click on the pallet stacker zone and decide regarding whether to eject the currently stacked empty pallets within the pallet stacker.
Figure 60: Empty Pallet Stacker window
Inbound-Outbound Station Screen
This page shows status of the IBOB zone and the status of every sensor in the IBOB. The operators can use the buttons to “Start”, “Reset Fault”, “Stop” and “Request to Enter”.
Figure 61: IBOB Station 1 page
Error History Page
Any active Error will be prominently displayed on every page ensuring operators are immediately alerted to the most recent error. To access a detailed list of all currently active errors, operators can conveniently click on this dialog. The “Go to Error History” button will redirect the page to the error history page.
Figure 62: Error Page Screen
Error History Screen displays all errors in a table. The operators can filter the history based on the date. The history displays the latest 10 records by default.
Figure 63: Error History Screen
Warehouse Inventory Page
The Warehouse Inventory page presents a list of all pallets within the system. Operators can click the 'Eject' button to request the ejection of a pallet. Additionally, in the top right corner, the 'Available Buffers' section displays the number of available buffers within the Mujin system.
.
Figure 64: Warehouse Inventory Screen (Pallet List)
In addition, the Warehouse Inventory page offers a 'Frame Map' feature for visualizing the frame's position on the map. Operators can easily switch between different views by selecting options from the dropdown menu.
Figure 65: Dropdown for Frame Map and Pallet List
Figure 66: Warehouse Inventory Screen (Map)
Ejecting Pallet
Operators can select a non-empty frame to view the frame's status and make decisions regarding the ejection of pallets.
Figure 67: Pallet status and ejection window
Slipsheet Bin Management
On the right-hand side of the page, Mujin offers management buttons for slipsheet bins. Operators can use the following functionalities:
- Request to Unload All: To unload all available slipsheet bins.
- Request to Induct All: To induct all empty slipsheet bins into the robot cells.
Figure 68: Slipsheet Bin Management tab
Slipsheet bins from the robot cell can also be ejected individually by clicking the respective slipsheet bin in the robot cell from the Warehouse Inventory Map screen. Press “Request to Unload” to eject the respective slipsheet bin.
Figure 69: Unloading single slipsheet bin popup
The slipsheet bins will be ejected in the slipsheet bin unload location. Location and steps to unload have been listed in Section 6.6.
Register A Frame
NOTE: This button is to be used only when a rack is delocalized. The AMR rack needs to be placed only in the area marked for registration. This system has an area near the pallet stacker marked in blue. |
This button is provided to register a frame during AMR rack delocalization. Pressing this button will move the nearest AMR to the frame and update its location.
Figure 70: Register a Frame button
Press confirm to acknowledge this operation.
Figure 71: Confirmation to Register a Frame
Inbound Outbound History Page
Inbound Outbound Page displays all IBOB records in a table. The operators can filter the data based on date.
Figure 72: Inbound Outbound History Screen
Fields | Description |
Inbound Station Name | The inbound-outbound station where the pallet inbounded |
Inbound Date | The date of inbound pallet |
Outbound Station Name | Where the pallet outbound |
Outbound Date | The date of outbound pallet |
Is Single SKU | If the pallet is single SKU |
Is High Priority | If the pallet is high priority |
Is Finished | If the pallet is finished |
Is Empty | If the pallet is empty |
Statistic Page
NOTE: Accessible to only Supervisor level and higher. |
The statistic displays all the information in our system. We can configure it to display the entire system performance or single robot cell performance.
Figure 73: Statistic Screen
Downloading Statistic Page
NOTE: Accessible to only Supervisor level and higher. |
The statistic page can only be downloaded on your personal PC/tablet using the steps mentioned below:
- Make you sure your personal PC/tablet is on the network as the controller.
- Go to your browser and type http://controller1175.com.
- Login in as Supervisor or Admin.
- Click the Menu (hamburger sign) on the top right to display the drop-down list.
- Click the Statistic page.
- Click the Data Export tab.
Figure 74: Picture showing Data Export tab
- Select the Data Interval, Date Range, and the Format of the file.
Figure 75: Picture showing download screen
Entering the cell
Under normal operating conditions, follow these steps for entering the robot cell:
- When there is no emergency, initiate the process by pressing the "Request to Enter" button on the door interlock (See section 5.3.1). The robot will come to a halt once it completes its current cycle.
- After the robot has stopped and the interlock is released, retrieve the interlock key to unlock the door, allowing entry into the cell. Keep the key with you while inside. (or place in lockbox and lock)
- When you are ready to leave the cell, return the interlock key to its designated location.
- Press "Reset" then "Start" button to restart the production cycle.
In the event of an emergency, follow these steps:
- If an emergency arises, promptly press the "Stop" button on the door interlock (See section 5.3.1). This action will halt the robot's operation immediately.
- Next, press the "Request to Enter" button on the door interlock.
- Once the interlock is released, retrieve the interlock key to unlock the door, granting access to the cell. Keep the key with you inside.
- Before leaving the cell, make sure the conveyor and gripper are cleared of workpieces.
- After leaving the cell, ensure to return the interlock key to its designated location.
Will be a different procedure. Not under daily operation [AR1]
Need to have back estop procedure and how to bypass for maintenance
Replacing the slip sheet bin
- Using the HMI, press the “Request to Unload All” to eject all the slipsheet bins (Refer to section 6.4.7.iii.).
Figure 76: Slipsheet bin unload location
- The slip sheet bins will move to the location shown in Figure 78.
- Once the slip sheet bins are in position, the stacklight in that area will turn green to indicate the operators to start the process (See section 5.4).
- Press the request to enter button, to release the key (See section 5.3.1).
- Open the door and keep the key with you.
- Remove the pallet with full slip sheet bins carefully using a forklift.
- Replace the pallet with an empty bin justified to the back of the rack (i.e. behind the caution tape). Make sure the racks are not moved from its location while performing this operation.
- Close the door and insert the interlock key in the designated location (See section 5.3.2).
- Press the "Reset" button on the door interlock (See section 5.3) or “Reset Fault” on the HMI (See section 6.4.3).
- From the HMI, press “Request to Induct All” to send all slip sheet bins to their respective robot cell and continue production cycle (See section 6.4.7).
Using the pallet stacker
The pallet stacker will automatically unload the stack of empty pallets onto the AMR, and it will transfer it to one of the IBOB stations. If in any case, the operator wants to unload the pallet stacker, they can use the HMI to unload (See section 6.4.4). For any other troubleshooting, refer to the Maintenance and Troubleshooting manual.
Basic troubleshooting guidelines
The following lists some of the troubleshooting procedures that might be required on a daily basis. For more details and troubleshooting procedures, refer to the Maintenance and Troubleshooting Manual.
Case Conveyor Jam Intervention
In the event of a jam, operators may need to manually intervene to clear the jam. Operators will have to press “Request to Enter” button on the door interlock and enter the cell. Clear the conveyor and any packages that are on the floor and exit the cell. Press “Reset” and “Start” to resume production cycle.
Operating the AMR
The AMR is only manually movable in brake release mode, in most cases, it cannot be moved when powered off. To engage brake release mode, press the brake release button. The AMR may automatically enter brake release mode under special conditions, one example is when it cannot recognize the QR code beneath it (green strip light). It is not necessary to orient AMR perfectly when lining up with a QR code, since the AMR will calibrate its orientation automatically.
On/Off Button:
The On/Off button is located on the front control panel. It is used to power on and off the robot. When turning on the robot, make sure to wait until the robot’s strip light is off before turning it back on. The AMR LEDs will turn solid white and emit three consecutive beeps to indicate the powering on process. Wait for the AMR LEDs to turn green, stand back. The AMR light will turn blue, and the AMR will spin and localize.
If it stays green after a long time move the AMR slightly so that it is centered on the code until it brakes. Stand back and it will turn blue and complete the spinning and localization process.
WARNING: Stand back at least 1.5 m from the AMR after turning on. AMR will spin and localize when the LEDs turn blue. |
Figure 79: Switching off/on the AMR
Emergency Stop Button (Front and Rear):
The emergency stop buttons are crucial safety features. Pressing the front or rear emergency stop button activates an emergency stop function that halts the robot's movement and operations immediately. The red strip light will be always on when E-stopped. Releasing the button allows for restarting the robot.
Enable: Press to engage the button.
Disable: Rotate in the direction of the arrow until the button is raised.
Manually Raising/Lowering button:
This button is located on both the sides of the AMR (front and rear). Press and hold the button for more than 6 seconds, the root will ascend or descend. The red light on the AMR will turn on or flashing, indicating that it has entered the manual mode. It includes raising and lowering actions. After completing one action, the AMR will automatically perform the next action. The robot stops lifting/lowering when the button is released.
Figure 80: Lowering lift of AMR
Brake release (Front and Rear):
This button controls the brake of the AMR, it should be activated when the AMR needs to be disable from self-controlled movement. The brake release state will allow the AMR to be manually dragged and will turn the red strip light into flashing mode. Brake release state can be activated by pressing the brake release and deactivated by pressing the button again.
Figure 81: Brake release button on AMR
AMR stuck in IBOB below Area Scanner
If the AMR is stuck below the area scanner and the system faults out, follow the steps mentioned below to resume:
- Confirm all other errors are cleared, no one is inside the area where the AMR is stuck and there are no packages on the floor near it.
- There will be a toggle switch located near the IBOB station. Toggle the switch shown below to “ON,” to move the AMR into the AMR Highway.
- Once the AMR is moved out into the AMR Highway and the Area Scanner is clear, toggle the switch back to “OFF” position.
- Reset all faults/errors and resume production.
Figure 82: AMR Toggle Switch
Pallet Stacker Jam
If the pallet stacker is jammed due to damaged pallets or off-centered pallets, then follow the steps below to recover:
- Enter the cell from the door closest to the pallet stacker.
- Put the stacker in manual mode by pressing the “Man” mode.
- Jog the pallet stacker from the control buttons located outside the cell. Jog it to unjam the pallet stacker. If all pallets can be lifted properly, exit the cell, ‘Reset’ and ‘Start’ the production cycle.
- If the AMR brings a pallet that is too off-center to the pallet stacker or if a broken pallet is at the bottom of the stack, a jam can be created like shown below:
Figure 83: Pallet jammed in Pallet stacker
- At least two team members will pull out the jammed pallet and AMR rack from the pallet stacker.
Figure 84: AMR rack being pulled out
- Remove the empty pallet. Perform a team lift on the empty frame and place within the bounds of the blue tape on the floor in the orientation shown below.
Figure 85: Rack placed within blue tape
- The AMR will remain under the pallet stacker. Press the brake release button on the AMR (See section 7.2). Please do not turn off the AMR until instructed.
- Move the AMR out of the pallet stacker by grasping the corner of the AMR as seen below.
Figure 86: Moving AMR manually
- Once you have removed the AMR from the pallet stacker, lower the lift of the AMR (See section 7.2).
- Move the now lowered AMR underneath of the rack.
Figure 87: AMR under the rack
- Press the brake release button pressed earlier. This will re-engage the brakes (See section 7.2).
- Turn off the AMR by pressing the power button. When all the lights on the AMR turn off, turn on the AMR by pressing the power button again (See section 7.2).
- Exit the cell and close the door.
- Reset and restart the AMR highway via the HMI master reset.
- Since the stacker is expecting a pallet on the frame, it will go into an error state.
- Press the “AUT Start” to put the pallet stacker in auto mode.
- Press and hold the “Reset Error” button on the pallet stacker to reset the fault.
Figure 88: Pressing the Reset button
- Should errors persist, go to the HMI, and read error messages.
- Should problems persist without resolution please contact Mujin support.
AMR Rack Delocalization
If the rack is moved by the operator while loading/unloading or due to any collision, the AMR will not be able pick up the rack. In this case follow the steps mentioned below:
Note: This applies only to racks delocalized in IBOB, slipsheet bin unload location and near pallet stacker. |
- If the system is in production cycle, stop the subsystem in which the rack delocalized.
- Enter the subsystem.
- There are floor markings that represent the rack legs. These markings will be present in each IBOB zone, slipsheet bin unload area and one near the pallet stacker.
- Position the rack on those floor markings. Make sure all legs are within the marked area.
- Once the rack is in position, exit the subsystem and close the door.
- Resume production cycle.
- The nearest AMR will try to localize the rack and continue operation.
For the racks that are delocalized in any other area or if the rack was moved for any reason, follow the steps mentioned below:
Note: This applies to racks delocalized in any area or if the racks were moved. |
- If the system is in production cycle, stop the subsystem in which the rack delocalized.
- Enter the subsystem.
- Clean and clear the floor of any debris or fallen packages.
- Check the Warehouse Inventory Screen-Map to verify the location of the rack.
If it matches with the actual location,
- Center the rack on the QR code present below the rack.
- Exit the subsystem and close the door.
- Reset and resume production cycle.
If it does not match with the map,
- Move the frame to the marked area near the pallet stacker. Make sure all the rack legs are within the blue square.
Figure 89: Marked area in blue near pallet stacker
- Press “Register a Frame” from the Warehouse Inventory Screen (Section 6.4.7).
- Exit the subsystem and close the door.
- Reset and resume production cycle.
- The nearest AMR will travel below this frame and update its location.
- The new frame will appear on the HMI in this location.
Ejecting Pallet
Pallet can be ejected from the system if the packages are out of spec, broken boxes, etc. Follow the steps mentioned below to do the following:
- Using the HMI, press the menu symbol to go to the Warehouse Inventory Page (Section 6.4).
- Go to the Frame map view (Section 6.4.7)
- Select the pallet that needs to be ejected from the system.
- Press “Eject” on the pop-up menu.
- The ejection command in the process when the “Eject” button turns to “Yes”.
- The pallet will be ejected to one of the IBOB stations and the strip light will turn flashing yellow to indicate that the pallet is outbound.
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