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Multiple-axis self-driving load-carrying platforms are impressive feats of engineering, capable of transporting enormous structures weighing many hundreds of tonnes. Their proper operation involves the co-ordination of steering, hydraulic level adjustment and diesel engine drive functions. And in some cases, multiple platforms are required to work in tandem to transport some of the largest structures. Therefore, CANbus control is a prime candidate for this type of application.
Platforms like these were prominently featured on the Channel 5 programme “Monster Moves”, carrying the control tower for Heathrow’s Terminal 5. And, sure enough, those platforms, manufactured by Goldhofer, feature CANbus control systems designed and built by Sensor-Technik.
Each platform includes a CANbus ESX host computer and a further ESX axis-control module. The platform’s ESX host communicates both with the axis-control module and the ESX host modules on as many other platforms as are required for any given moving task, ensuring tight synchronisation of movement in any multiple-platform system.
The ESX host computer controls the steering on each platform directly, based on information from the other ESX host modules, and from angle feedback signals from the wheels delivered via the ESX axis-control module. The axis-control module monitors the speed of each wheel and feeds this information back to the ESX host for automatic throttle adjustment. The CANbus controllers also monitor and control the proportional valves for the hydraulic level adjustment system.
This is a perfect illustration of how multiple CANbus controllers can work together in a modular decentralised control system. And with just a single pair of wires required for the transmission medium, cabling is kept to an absolute minimum. The high transfer rates and high reliability inherent in CANbus systems ensure all the platforms in any multiple-platform system receive their control signals at exactly the same time, enabling the all-important tight synchronisation of movement.
