Views: 0 Author: Site Editor Publish Time: 2026-08-04 Origin: Site
Conventional steel coil warehouses rely heavily on manually operated overhead cranes. Performance varies from operator to operator, causing inconsistent efficiency and safety concerns. Storage positions are often decided on the spot without standardized rules, reducing effective warehouse capacity. Inventory tracking requires periodic physical counts, leading to frequent mismatches between system records and actual stock. Multiple roles—crane operators, floor coordinators, and warehouse clerks—must coordinate manually, creating a labor-intensive workflow with limited throughput.
A major steel producer decided to address these issues by deploying an unmanned system in its finished coil warehouse. The facility consists of two bays, each equipped with an intelligent overhead crane and vehicle loading/unloading stations.
The project delivers a comprehensive automation solution covering warehouse management, intelligent scheduling, and automated material handling. Core technologies include high-precision 3D positioning, sway control, LiDAR scanning, online condition monitoring, and smart dispatching. A centralized warehouse management system orchestrates all crane operations, enabling fully unmanned inbound, stacking, restacking, and outbound workflows. The system design prioritizes reliability, advanced technology, operational practicality, and open-architecture scalability, and complies with all applicable national and industry standards.
Click to watch: Live footage of unmanned overhead crane system in operation—fully automated from pick-up to placement.
The unmanned crane system comprises six major subsystems: automation control software, PLC-based electrical control, warehouse management, vehicle identification, intelligent lifting attachments, and video surveillance.
Key performance parameters: crane positioning accuracy ±1 mm on both travel and cross-travel axes, hoist positioning accuracy ≤±20 mm, average coil handling cycle <4 minutes, operational accuracy ≥99.99%, and vehicle recognition scan time <20 seconds.
（1）3D Positioning System (Proprietary technology of Wuhan Forward Technology)
Combined solution using Gray Code busbar, laser rangefinders, and encoders:
Bridge travel (X-axis): Gray Code busbar with non-contact sensing, repeatable positioning accuracy ±1 mm, IP54-rated, service life exceeding 10 years.
Trolley travel (Y-axis): Dual laser rangefinders cross-validating each other, accuracy ≤±15 mm, PROFINET output to PLC.
Hoist height (Z-axis): Absolute encoder plus incremental encoder for redundancy, position retained after power loss, accuracy ≤±20 mm.
（2）Anti-Sway Control System (Proprietary technology of Wuhan Forward Technology)
Actively suppresses load swing by dynamically adjusting bridge and trolley acceleration/deceleration profiles. Swing angle accuracy <±0.5°, eliminating over 95% of pendulum motion and achieving positioning deviation <±25 mm, significantly reducing cycle times and extending mechanical service life.
（3）Dynamic Collision Prevention & Real-Time Inventory Verification (Proprietary technology of Wuhan Forward Technology)
Before each lift, the system scans the target saddle position and inter-locks with the crane PLC to prevent placing coils onto occupied positions or attempting lifts from empty locations. After placement, the system automatically updates the coil's coordinates (accuracy ±30–50 mm) and performs a real-time inventory comparison, immediately flagging any discrepancies—eliminating routine physical counts.
（4）Crane Structure and Electrical Control
The crane features a box-section double-girder design with offset rails. The control system uses a Siemens S7-1500 series PLC with no fewer than 10% spare I/O points and at least one spare analog channel. All three motion axes use AC variable-frequency drives with PROFINET communication to the PLC. The operator's cab includes a dedicated control console with local operation as the highest-priority mode, overriding all remote commands. A 10-inch touchscreen provides real-time status monitoring.
（5）Wireless Communication
Industrial 5.8 GHz wireless base stations with IP67-rated enclosures and -40 to 75°C operating range. Redundant mesh network architecture ensures <1% packet loss and uninterrupted operation even with single-link interruptions.
（6）Intelligent Coil Clamp
The clamp includes its own PLC and communicates wirelessly with the main controller. Comprehensive sensing capabilities include: load detection, coil centering verification (vertical laser sensor pair), clamping force monitoring (adjustable 1–20 mm range), open/closed limit detection, opening distance measurement via absolute encoder, bottoming detection, empty-lift prevention, tilt angle measurement, and rotation angle sensing.
（7）Safety Protection
Bridge anti-collision uses three-tier redundancy: software limit (real-time Gray Code positioning), laser deceleration zone, and mechanical travel limit. A dual-sided LED information panel displays crane operating status to ground personnel.
（1）Ground Vehicle Identification System
A 3D LiDAR scanner mounted above the parking position captures point cloud data, from which algorithms extract precise 3D coordinates of coils and saddles (center position in bridge/trolley axes, height, and tilt angle). Data is transmitted to the WMS and client displays via TCP/IP. The scanning pan-tilt unit uses servo motor, harmonic drive, and absolute encoder closed-loop control with angular resolution <0.0007°. A protective dust enclosure minimizes lens contamination and reduces high-altitude cleaning frequency.
（2）Ground Safety Management
The operating area is enclosed by safety barriers, with separate personnel and vehicle entry points. Traffic lights guide vehicle access. Audible/visual alarms activate where crane paths cross pedestrian walkways. Security gates are interlocked with the crane PLC to prevent unauthorized entry.
（3）Vehicle Dispatching System
Includes self-service check-in kiosks, LED display boards, and handheld terminals. Drivers follow LED instructions to designated parking positions, check in at the kiosk against their work order, and the overhead LiDAR automatically initiates a scan. Handheld terminals allow warehouse staff to perform inbound checks, inventory verification, and material quarantine operations.
（4）Floor Saddles and Guardrails
Fixed saddles and protective guardrails are installed throughout the warehouse to ensure consistent, orderly coil placement with known coordinates.
Unmanned Control Software System (Proprietary software of Wuhan Forward Technology)
Deployed on servers in the central control room, the system includes the following functional modules:
Module | Function Description |
|---|---|
3D Warehouse Management | Real-time visualization of static elements (columns, barriers, rails) and dynamic entities (cranes, coils, vehicles) |
Operations Dashboard | Vehicle recognition results, coil details, work order list, daily statistics (inbound/outbound volumes, current inventory, available positions), real-time crane coordinates and speed curves |
Fault Diagnosis | Real-time fault display with historical node trace-back for root cause analysis |
Task Scheduling | Full-warehouse or buffer-zone optimization strategies; click-to-generate move commands on the 3D model, with automatic identification of inbound/outbound/restacking operations |
Data Reporting | Historical operation data exportable by day, month, quarter, or year |
System Administration | Role-based access control (dispatcher vs. viewer), configurable storage rules per saddle |
Interface Management | Two-way interface with MES for planning and performance feedback closed loop; interface with transfer cars for safety interlock (optional); reads LiDAR data to generate outbound orders automatically |
Mobile Control Unit (Proprietary product of Wuhan Forward Technology)
One-to-many capable, aluminum alloy housing, no cutout installation required, connects to the network via standard industrial bus, enabling remote manual override of multiple cranes from the control center.
Video Surveillance System
High-definition cameras are installed throughout the warehouse and on each crane at critical points (hook, drum, and under-bridge area). Video feeds at 720p or higher are transmitted to the control room for storage and real-time display, ensuring full visual coverage without blind spots.
The unmanned crane system described in this case study has been successfully deployed across multiple industrial sites. Representative projects include:
Wuhan Steel Group Logistics Co., Ltd. – No.21 Warehouse Automatic Crane Control System Retrofit.
Foshan Media Material Supply Co., Ltd. – Shunde Plant: 25-ton unmanned overhead crane retrofit project (4 units).
Jiangyin GangFa International Logistics Co., Ltd. – Warehouse A: Unmanned crane system equipment contract.
Gansu Jiu Steel Group Hongxing Iron and Steel Co., Ltd. – Intelligent transformation project: Crane unmanned system.
Following deployment, the project delivered measurable improvements:
Operational efficiency: Average coil handling cycle consistently below 4 minutes, meeting production targets. Vehicle recognition completes in under 20 seconds, and with queue management, average vehicle turnaround time has been significantly reduced. Cranes operate 24/7 with minimal downtime, achieving higher equipment utilization and balanced workloads across bays.
Precision and safety: Operational accuracy reached 99.99%, eliminating variability associated with manual operation. Multi-layered collision avoidance and real-time inventory verification have resulted in zero safety incidents since commissioning. Physical barriers, warning systems, and interlocked gates provide complete personnel isolation, while video surveillance ensures second-level response times with full coverage.
Cost reduction: Workforce reduced by over 60%, yielding substantial annual labor savings. Automated inventory verification cut reconciliation costs by more than 90%. Report automation improved management efficiency by 60%. Standardized operation profiles reduced mechanical wear, and predictive fault alerts lowered maintenance costs by approximately 30%.
Digital transformation: The warehouse is now managed through a transparent 3D visualization platform. Deep integration with MES/ERP creates closed-loop information flow from planning to execution. Historical data is fully retained and queryable, supporting continuous optimization and data-driven decision-making. The system architecture is designed for future expansion.
This project demonstrates how an integrated approach—combining high-precision positioning, active sway control, LiDAR sensing, smart lifting attachments, multi-layer safety systems, and digital twin scheduling—can transform a labor-intensive steel coil warehouse into a fully automated, intelligent operation. The solution is versatile and replicable, suitable for both greenfield facilities and retrofit projects, and represents a proven reference for logistics automation in the steel industry.
