Controlling the direction of "walkie" type forklifts and pallet jacks on sloping ground

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    Purpose - The purpose of this paper is to develop an electronic solution to effectively lock swivelling wheel steering positions to driver-control. Simple and affordable systems are described to assist forklift users in steering their walkie type forklifts or pallet jacks across sloping ground. Design/methodology/approach - A rolling road was created as an assessment tool and trials with both the test bed and in real situations were conducted to evaluate the new systems. The small swivel detector that was created could be successfully attached to swivelling wheel swivel bearings. Findings - The new system was successful, robust and was not affected by changeable parameters. The simple systems assisted hand truck operators in steering their forklifts across sloping ground without veering off course. The systems overcame the problems associated with forklifts that steer using two swivelling wheels and meant that less work was required from hand truck operators as their forklifts tended to travel in the desired direction. Research limitations/implications - Experiments demonstrated that calibrating forklift controllers for straight-line balance and optimizing motor-compensation did not solve this problem. Instead, swivelling wheel angle was selected to provide feedback. At the point when veer is first detected, a forklift has already begun to alter course and the job of the correction system is to minimize this drift from the desired course. Practical implications - The forklifts and pallet jacks often steer by having swivelling wheels but problems with this configuration occur when a forklift is driven along sloping ground because they can swivel in the direction of the slope. Gravity then causes the forklift or pallet jack to start an unwanted turn or ``veer'' and the vehicle goes in an unintended direction. This situation is exacerbated for vehicles with switch controls, as switches cannot provide fine control to trim and compensate. Originality/value - Each year in the United States, over 100 employees are killed and 36,000 are seriously injured in accidents involving forklift trucks and pallet carriers. This is the second leading cause of occupational fatalities in ``industrial'' type workplaces. The research aims to make the use of this type of equipment safer and the systems can be attached to many standard forklifts and pallet jacks.
    Original languageEnglish
    Pages (from-to)317-324
    Number of pages8
    JournalAssembly Automation
    Issue number4
    Publication statusPublished - 2008


    • SERG ARP
    • forklift trucks
    • lifting equipment
    • pallets
    • control technology
    • teleoperation
    • robotics
    • feedback
    • users


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