Abstract: A vehicle body inclination angle regulating unit (17) includes a balancing oil cylinder (10). One chamber of the balancing oil cylinder (10) is connected with an oil tank (5) and an oil source for leveling operation via a first one-way damper valve (8) and an electric controlled switch valve (7), and the other chamber of the balancing oil cylinder (10) is connected with a non-rod chamber of a suspension oil cylinder via an electric controlled shutoff valve (14) and a second one-way damper valve (9). In addition, an automatically-leveling hydropneumatic suspension mechanism includes at least two pairs of suspension oil cylinders (12), vehicle body inclination angle regulating units (17), a vehicle body transverse inclination angle sensor (1) and a control unit (3). Each suspension oil cylinder (12) is correspondingly provided with the vehicle body inclination angle regulating unit (17) including the balancing oil cylinder (10).

Abstract: A hydraulic control system and a hydraulic control method are disclosed. The hydraulic control system comprises a first closed pump (P1) and a first engine (M1) connected with each other, a second closed pump (P2) and a second engine (M2) connected with each other, and a hydraulic motor (P3). The first closed pump (P1), the second closed pump (P2) and the hydraulic motor (P3) are connected in parallel. Compared with the prior art, the present hydraulic control system has advantages of wider engine model selection range, higher reliability and better micro-motion performance.

Abstract: A power unit includes two or more power modules (1, 2, 3), each comprising an engine (11), a transfer case (12) connected to the engine (11) and a hydraulic pump set (13) connected to the transfer case (12). A controlling method for the power unit is also disclosed. Compared to the prior art of using a single super high power engine, the hydraulic mobile crane using the in power unit has advantages of low cost, high reliability, and not being subjected to the restrictions by road transportation conditions during transportation.

Abstract: A single-cylinder pin-type telescopic boom track optimized control method and control system thereof are applied to switch between any two working conditions of any sections of a telescopic boom. The method and system establish a constrained condition according to the stroke of a telescopic oil cylinder. When the telescopic boom is changed from the current state A to the target state B, the most rapid and convenient telescopic path can be obtained based on the current position of the pin mechanism and other conditions. The method and system greatly improve the telescopic reliability and work efficiency of the single-cylinder pin-type telescopic boom, and are applied to the telescopic boom of any engineering machine, in particular to the telescopic boom of a heavy duty crane.