Tadano Ltd. has introduced the "Wind-Sense" load sway suppression system for its GR-1300XL-4 series 130-ton rough terrain cranes, targeting mechanical and HVAC unit installations on urban rooftops where wind conditions and restricted sightlines compound the challenges of precise load placement. When a 5-ton rooftop chiller is suspended at a 40-meter radius, even a modest 5-meter-per-second breeze causes the load block to pendulate continuously, and the operator-positioned in the carrier cab at ground level-often cannot see the load's position relative to its landing point. Traditional sway control relies on the operator manually modulating the hoist and swing to "pump" the load into position, a technique that requires considerable skill and frequently results in the load striking the roof parapet or structural steel.
The Wind-Sense system integrates a "Tri-Axial Accelerometer Package" on the load block and a "Boom-Tip Wind Velocity Sensor" that measures the actual wind vector acting on the suspended load. The engineering breakthrough is the "Harmonic Counterphase Winch Control." The system calculates the pendulum's natural period-determined by the hoisted rope length and the load mass-then drives the hoist winch forward and backward at the pendulum's natural frequency but 180 degrees out of phase. By shortening the rope as the load swings forward and lengthening it as the load swings back, the system injects energy into the pendulum at the opposite phase, progressively damping the swing amplitude within 3 to 4 pendulum cycles.
Simultaneously, the system modulates the swing and boom telescoping cylinders in micro-increments to counteract the lateral wind force detected by the boom-tip anemometer. The operator sees a real-time "Sway-Free" indication on the cab display when the load is stationary relative to the ground, indicating that it is safe to lower onto its landing point. This harmonic counterphase control reduces load placement time on blind rooftop picks by 40 percent and prevents the load impacts that previously dented rooftop HVAC units and damaged structural steel during placement.
