This paper discusses the proposal of use of a hydraulic amplifier as a drive system's supporting element-for example, the drive of work equipment in unmanned ground vehicles (UGVs) is powered by electricity. Such a solution can provide very high forces on actuators of UGV (cutters, spreaders, hydraulic wrenches, and chisels) with relatively low electricity demand. The experimental tests of the amplifier in laboratory conditions for various power supply and load configurations of the amplifier are presented. The obtained test results allowed to estimate its usefulness in the solutions proposed above and to determine the further path of detailed research for selected electrical system solutions equipped with hydraulic amplifiers.
Additive manufacturing (AM) of spare parts is going to become more and more common. In the case of hydraulic solutions, there are also some applications of AM technology related to topological optimization, anti-cavitation improvements, etc. An examination of all available research results shows that authors are using specialized tools and machines to properly prepare AM spare parts. The main aim of this paper is to analyze the influence of quick repair of the damaged slipper-retainer from an axial piston pump by using an AM spare part. Hence, it was prepared with a 100-h test campaign of the AM spare part, which covers the time between damage and supply of the new pump. The material of the slipper-retainer has been identified and replaced by another material—available as a powder for AM, with similar properties as the original. The obtained spare part had been subjected to sandblasting only to simulate extremely rough conditions, directly after the AM process and an analysis of the influence of the high surface roughness of AM part on wear measurements. The whole test campaign has been divided into nine stages. After each stage, microscopic measurements of the pump parts’ surface roughness were made. To determine roughness with proper measurements, a microscopical investigation was conducted. The final results revealed that it is possible to replace parts in hydraulic pumps with the use of AM. The whole test campaign caused a significant increase in the surface roughness of the pump’s original parts, which was worked with the AM spare slipper-retainer: (1) from Ra = 0.54 µm to Ra = 3.84 µm in the case of two tested pistons; (2) from Ra = 0.33 µm to Ra = 1.98 µm in the case of the slipper-retainer. Despite significant increases in the surface roughness of the pump’s parts, the whole test campaign has been successfully finished without any damages to the other important parts of the whole hydraulic test rig.
The following paper describes research on the influence of hydraulic accumulator parameters on the efficiency of energy recovery for a simulation model of a wheel loader using the results of experimental research. A design solution for the energy recovery system for the loader attachment was presented, which allows for the recovery of the potential energy of the boom, bucket, and load. The presented simulation model was developed based on a real object. The necessary operating parameters were determined using experimental tests. The study used the co-simulation method of mechanical and hydraulic models in order to more accurately reflect the actual behavior of the research object. The validated simulation model was extended with the developed energy recovery module based on a hydraulic accumulator. The results of the conducted tests have indicated the influence of hydraulic accumulator parameters on the efficiency of energy recovery and potential directions for further research.
The paper describes the wheeled rescue robot FRR drawn up by a team of Engineering Machines and Robots at Military University of Technology. It also shows a brief description of predicted for implementation tasks by FRR and probable problems that might occur and should be solved. Next the paper describes the method and the model which served to simulation evaluation of rigidity for robots suspension system. Describing the simulation model, used simplified assumptions and the method of calculating the basic parameters for model were described. The following chapter presents simulation that the model was tested through and some model results of the test. In the final phase of the article the conclusion and discussion is presented.
Neutralization hazardous materials still creates many problems. For this purpose is often used an EOD (Explosive Ordnance Disposal) engineer robot manipulator equipped with hydraulic drive system and intuitive control system. Application of intuitive control systems mainly improves the accuracy of performing tasks by copying and tracking the movements of the operator's hand. However, it wasn't found any information about influence of this kind of manipulator's structures on the effector's accuracy using intuitive control systems. Taking this into consideration the research of two kinematic structures of this manipulators (serial and serial-to-parallel) were performed. On their basis has been achieved an improvement in control accuracy for serial-to-parallel structure. The simulation studies included investigation of nonlinearities and dynamics of an electrohydraulic proportional valve as a hydraulic control element of manipulator hydraulic drive system.
More often Unmanned Ground Vehicles (UGV) support or replace human in dangerous tasks performing. Usually this operations are realizing in hard conditions in rough terrain. UGVs effectively use determines its ability to obstacle negotiating, to reach high adhesion force, drawbar pull and extra longitudinal and lateral stability of UGV. Variety missions determining of use in UGVs reconfigurable and control suspension system. It is able to meet this requirement thanks to use hydropneumatic components in them suspension system. However currently it is very hard to developed characteristic of such a suspension systems. In literature there is no clear guidelines for suspension systems of teleoperated UGVs. This paper presents results of hydropneumatic suspension system research on heavy UGV.