Robust On-Board Communication for Forklifts

Sammanfattning

Modern forklifts increasingly depend on reliable on-board communication systems to support sensing, control, automation and safety-related functionality such as cameras and automatic stopping. Meanwhile, the inside of a forklift introduces challenges including electromagnetic interference, multi-path propagation, mechanical stress and dynamic mast movement. This thesis investigates and compares wired and wireless communication technologies intended for robust on-board communication in Reach Rider Electric (RRE) and Reach Auto Electric (RAE) forklifts. The main objective is to identify which communication technologies provide robust performance when electromagnetic, mechanical and propagation-related constraints are considered together. For the wireless technologies, ray-tracing simulations are used to derive realistic channel parameters based on warehouse and forklift geometry. Extracted channel parameters such as path loss, delay spread and K-factor are used in communication-system simulations under AWGN, Rayleigh and Rician fading channels. The wired technologies are evaluated using electrical channel and impairment models including impulsive noise, harmonic disturbances and timing-related impairments representative of industrial environments. Fiber-optic communication is additionally studied through optical attenuation and mechanical impairment modeling. The simulation framework enables controlled comparison between technologies, while the SDR and prototype measurements provide practical validation of selected effects. Fiber-optic communication demonstrates the highest robustness against electromagnetic interference, while BLE demonstrates strong robustness and reliable communication performance in the investigated wireless scenarios, particularly when lower-rate PHY modes are used. WiFi achieves high throughput but is generally more sensitive to propagation impairments and environmental variation. CAN and IO-Link show predictable and robust operation under moderate impairment conditions but remain susceptible to conducted disturbances and cable-related limitations. A central finding is that mast state and installation conditions affect communication performance more strongly than mast motion speed alone. Real-world SDR measurements and prototype evaluations show good agreement with several simulated trends, particularly regarding the influence of multi-path propagation, mast movement and changing line-of-sight conditions. The results therefore indicate that simulation-driven communication evaluation can provide useful guidance during the design of industrial on-board communication systems. Overall, the thesis demonstrates that robust forklift communication requires careful consideration of both the physical environment and the selected communication technology to achieve reliable and safe operation. The results support a hybrid on-board communication architecture where technology selection is based on link criticality, EMC exposure, bandwidth demand and mechanical integration.