Design and Experimentation of an Adaptive Leveling Boom for a Self-Propelled Sprinkler Irrigation Machine in Hilly Terrain

Highlights An adaptive leveling boom was developed for self-propelled sprinkler irrigation machinery operating in hilly terrain. The proposed boom achieves multi-degree-of-freedom posture adjustment through electric-actuator-based lifting and worm-gear-driven swing regulation. Integrated dynamic, finite element, and modal analyses supported boom optimization and achieved a 13% mass reduction while maintaining structural safety. Prototype tests confirmed improved boom stability under no-load, operating-pressure, and simulated obstacle conditions. Abstract. To improve the terrain adaptability and operational stability of self-propelled sprinkler equipment in hilly terrain, we developed an adaptive leveling boom based on electric actuator–driven lifting and a worm gear–based swing mechanism. A dynamic model of the lifting mechanism was established, and key structural parameters were optimized using a genetic algorithm to improve dynamic smoothness and stability. Based on static and modal analyses, the boom was further optimized for lightweight design and structural safety using the analytic hierarchy process. After optimization, the maximum deformation of the boom model was 0.78 mm. The maximum stress was 170.37 MPa, and the safety factor reached 1.38. Under typical operating conditions, stress and strain satisfied strength requirements. Constrained modal analysis confirmed that resonance was avoided within the primary operating frequency range. The boom weight was reduced by 13% to 165 kg, achieving lightweight design objectives while significantly improving structural strength and dynamic stability. Comparative prototype tests were conducted between the proposed boom and a conventional boom under no-load, operating-pressure, and simulated slope-obstacle disturbance conditions. The validation included eight no-load test groups, three operating-pressure levels (0.1, 0.2, and 0.3 MPa), and four simulated slope-obstacle arrangements, with five repeated trials per arrangement. A multi-index comprehensive evaluation model was established to quantify boom stability. Under the balanced no-load condition, the stability index of the proposed boom reached 0.93, representing a 22.4% improvement over the conventional boom. At operating pressures of 0.1, 0.2, and 0.3 MPa, stability improved by 16.8%, 26.4%, and 32.9%, respectively. Under simulated conditions involving combined 15° slopes and obstacles, the proposed boom rapidly recovered to a stable state with reduced displacement fluctuations. These results demonstrate that the proposed boom improves posture stability and disturbance recovery under controlled and simulated hilly-terrain conditions, providing a structural basis for further field-scale evaluation and a practical technical reference for enhancing the terrain adaptability and operational stability of mobile sprinkler irrigation equipment. Keywords: Adaptive leveling boom, Hilly tea plantation, Lightweight design, Stability analysis, Structural optimization, Self-propelled sprinkler irrigation machine.