XCMG has introduced a fully electronic "steer-by-wire" system for its flagship GR215 motor grader series, marking a departure from traditional hydraulic steering columns. In conventional graders, the steering wheel is mechanically linked to the hydraulic control valve, meaning the number of steering wheel turns is fixed. This can be cumbersome when the operator needs to make sharp turns at low speeds or minute adjustments at high speeds. XCMG's new system replaces the mechanical column with an electronic joystick and steering wheel sensor.
The system utilizes two redundant hydraulic steering cylinders controlled by a high-speed Electronic Control Unit (ECU). The ECU processes the operator's steering input and calculates the required flow to the cylinders based on the machine's ground speed. At speeds below 5 km/h, the steering ratio is aggressive, allowing the operator to turn the front wheels from lock to lock with just two rotations of the wheel. At speeds above 20 km/h, the ratio becomes numb and stable, preventing over-correction on haul roads.
A critical innovation is the "Side-Slope Auto-Correct" feature. When the grader is working on a steep embankment, gravity pulls the machine downhill. The ECU uses an inclinometer to detect this drift and automatically sends micro-pulses to the steering cylinders to keep the machine tracking straight, without the operator needing to constantly fight the wheel. This reduces operator fatigue by over 40% during long shifts. By decoupling the steering from the chassis, XCMG has also improved safety, as the system can automatically counter-steer if it detects a potential rollover situation.
