A Hydro-pneumatic Suspension of the Horizontally Balanced Loading Platform

The subject of research is the horizontally balanced loading platform on soft suspension.

Deviation from the horizontal direction of the platform can be caused by:

- Displacement of the gravity centre of main unit load placed on it from the vertical axis of the platform;

- Displacement of the mass centre of the load dispersed on the platform plane from its vertical axis;

- Adding a load which gravity centre does not coincide with the gravity centre of the main load.

In specific cases the use of complex and expensive tracking systems of high accuracy to balance loading platforms horizontally can be justified, e.g. when mounting the optical measuring or observation systems on a platform.

The aim is to assess the possibility to use the soft hydro-pneumatic suspension with a low power supply unit to provide horizontal balance of platform.

The paper offers a soft hydro-pneumatic suspension design of the rectangular loading platform based on four differential hydraulic cylinders to be the supports for two diagonal beams of the platform.

The head and rod ends of each pair of the beam hydro-cylinders are cross-pipe connected, and to compensate for a difference between the volumes of head and rod ends of cylinders because of their differentiality, there are hydraulic bag-type accumulators installed in the hydraulic suspension system.

The research technique involves the development of a mathematical model of the loading platform hydro-pneumatic suspension followed by its approbation using numerical methods. The paper presents algorithms of engineering analysis of parameters and structural dimensions of hydraulic suspension components.

In order to assess the adequacy of the developed mathematical model of a hydro-pneumatic suspension the paper studiesthe an effect of the following factors on the quality of the platform stabilization in the horizon:

 initial volume values of the gas chamber of hydraulic accumulators;

 pressure level of initial pressurization of hydraulic accumulators with nitrogen;

 differentiality degree of the suspension cylinders;

 value of the gravity centre displacement with respect to the vertical axis of platform;

 additional loading of the platform by the load undisplaced with respect to the vertical axis of platform.

In the context of calculating a hydro-pneumatic suspension of the platform loading diagonal beam of 2 m length, weighing 500 kg, with a load of 5,000 kg was shown that at the greatest displacement of the load gravity centre to the edge of the beam a deviation of the beam relative to the horizon is one angular degree, at most.

The work deals with creating the soft stabilized platform suspensions for stationary systems and mobile units.

As a result, a developed mathematical model allows the following:

- to show the theoretical possibility to create a soft hydro-pneumatic suspension of the loading platform based on four differential hydro-cylinders and four hydraulic accumulators to provide an acceptable accuracy of the loading platform balance in the horizon when the mass centre of the load placed on it is displaced with respect to the vertical axis of the platform;

- to find that the initial stiffness of the hydro-pneumatic suspension, defined by parameters of its hydraulic system, has little effect on the quality of the platform balance in the horizon.

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