Abstract:To enhance the stability and safety of the self-propelled wide-span operation platform during its walking operation, an adaptive omnidirectional leveling system based on a four-point hydraulic active suspension was designed, using the self-propelled platform as the research subject. The system employs LUDV load-sensing technology to improve hydraulic control performance and achieve synchronous control under multi-load parallel conditions in the four-point suspension hydraulic system. A multi-sensor setup was used to detect the platform′s posture in real-time, and through the integration of "following leveling" and "anti-false leg" control strategies, a dual-loop PID algorithm with anti-saturation integration was employed to compute and output control signals. These signals were cross-validated with the results from the suspension cylinder protection logic and anti- false leg logic algorithms to realize real-time omnidirectional posture adjustment of the platform by controlling the suspension cylinders. To validate the effectiveness of the LUDV load-sensing technology in the four-point hydraulic active suspension, a simulation model of the suspension system was developed in AMESim, followed by experimental testing. The test results indicated that under varying loads with identical openings, the maximum stroke deviation among the cylinders was 19.51 mm, with a maximum deviation rate of 6.27%. Furthermore, to demonstrate that the flow rate of each actuator was independent of load size, tests under load ratios of 1:1.35:1.71:2.07 with proportional control signals showed a motion stroke ratio deviation of 1:1.35:1.71:1.92, confirming both the independence of flow from load size and good synchronization. This verified the effectiveness of the LUDV load-sensing technology for the four-point hydraulic active suspension. In real vehicle tests, the static test results showed that the system could converge the vehicle′s body tilt angle within 0.5 °. Dynamic tests revealed that the adaptive leveling system reduced the maximum body tilt angle by 58.0% during lateral movements and 55.4% during longitudinal movements, while preventing the occurrence of false leg phenomena, effectively improving the platform’s stability and safety during operation.