Papers by Keyword: Hydraulic Excavator

Abstract: Synchronous test platforms were built to test the dynamic stress and working device attitude. The dynamic stress spectrums of all the test points under a variety of common conditions were obtained. The digging gestures corresponding to the peak of the dynamic stress spectrums were found out and taken as the specified digging gestures for the calculation of the static stress. The static stress nephogram of working device under the specified digging gestures was calculated using traditional static strength analysis. By conducting statistical analysis on the ratio of dynamic stress and static stress of all the testing points. Then, the range of generalized dynamic factor of working device was obtained.

Abstract: In order to observe the kinematic characteristic and dynamic characteristic of working state of hydraulic excavator, and aim at the complexity and time consuming of the numerical calculation and field test, the hydraulic excavator working device motion simulation and analysis scheme is put forward. By kinematics simulation, the envelope trajectory of the manipulator and the basic working parameters are got; by dynamics simulation, the force of each hinge in symmetrical and offset loadings is got, and the most hazardous working condition and hinge are determined. Thus provided the basis for strength analysis and design optimization of hydraulic excavator working device. Accordingly, a simulation analysis method to study the dynamics of the working device in hydraulic excavator is provided.

Abstract: Based on low utilization rate of energy and high fuel consumption, a parallel hydraulic & electric configuration for hybrid excavator was proposed according to the capacitor and motor. The mathematical model of key components such as engine, electric motor, and capacitor were established. For the hybrid power system based on SUNWARD 20T hybrid excavator, the paper established simulation model and analyzed the energy saving effect of hybrid system by simulation based on the actual load spectrum of hydraulic excavator as input signal. The results indicate that adopting the parallel hybrid system are helpful to improve the energy saving effect of hydraulic excavator, and the energy saving efficiency is about 23.6%.

Abstract: Nowadays with the high fuel costs, the stress for energy saving and green emission of construction machineries, while not sacrifice of the operating performance, safety and dependableness, particularly for hydraulic excavators (HYEXs), are extremely exaggerated. As a result, electro-hydraulic actuators (EHA), that is promoted and with success applied to industry, is recently introduced to HYEXs. The aim of this paper is to propose a new style of excavator - electrical excavator (ELEX) - with energy saving capability using the EHAs. Each of the hybrid actuators is driven by an electrical motor/generator for retrieving a potential energy or a kinetic energy at the time of lowering or slewing stoppage of the excavator. An excavator having a hybrid boom system (HBS) is analyzed. Finally, operating efficiency and energy consumption of the projected excavator area unit are clearly studied. Keywords: Hydraulic excavator; electric excavator; electro-hydraulic actuator; control

Abstract: Based on the bucket teeth load-time courses calculation model under bucket digging condition, the stresses on the hydraulic cylinder piston rods of boom and bucket and the real-time length of bucket hydraulic cylinder were set as measured variables, and a measuring method of the bucket teeth load-time courses was developed which had the advantages of less measuring points, simplified measurement process and low cost. The bucket teeth load-time courses were calculated by inputting the measuring data into the self-developed Constructing Hydraulic Excavators Load Spectrum software, and its characteristics of each digging step in one excavation cycle at digging macadam were analyzed. Then, using rain-flow counting module in FE-SAFE software, the statistical graphs of bucket teeth load-time courses were acquired which could provide the basis for hydraulic excavator reliability design and fatigue life prediction.

Abstract: In order to recycle energy during rotary phase of hydraulic excavator in the braking, this paper proposes a hydraulic slewing system based on secondary regulation control. In the constant pressure network, secondary regulation system can make variable motor reach the set speed quickly and smoothly through the motor PID feedback control, which can control power of the whole system ,while the general volume transmission system mainly through changing the flow of pump. Accumulator is used to recycle braking energy and reuse for next acceleration,which improve work efficiency. The simulation results shows that the energy recovery and reusing efficiency of rotation braking recovery system are 65.9% and 47.3%, the system achieves the goal of energy conservation and emissions reduction.

Abstract: Taking a type excavator as an example, three-dimensional model was established using CATIA software, using the ADAMS software to the dynamic simulation analysis; get the movable arm hinged point load curve. The maximum load into ANSYS finite element analysis was carried out on the derrick structure, derived from ANSYS MNF file imports ADAMS to get the coupled model and dynamics analysis, get the time-varying curve working device. Results show that the coupled model is more in line with the actual, work can be more fairly reflect device performance, can provide the basis for further optimization of the structure of excavator.

Abstract: It was incomplete and may have missed some dangerous working conditions to select several typical working conditions only in traditional strength analysis of hydraulic excavator. Therefore, the paper proposes a strategy that takes the working conditions when the load at each hinge of working device reaches largest into account. The working device of a 21t hydraulic excavator was analyzed with finite element analysis method when comparing these working conditions with the traditional typical ones. The results come out that the largest stress of boom, arm and bucket under these conditions increased respectively by 4.6%, 5.6% and 19.1% compared with the traditional most dangerous conditions. Consequently, in addition to the traditional typical conditions, it will be more safe and reliable to analyze the strength with the largest hinge loads conditions.

Abstract: Shortages of skilled labor,extensive dangerous work,and technological advances are forcing rapid change in the construction industry, thus motivating construction automation,research and development of unmanned execution technologies for use to enhance safety has been undertaken.This paper presents an outline of research and development concerning automation of hydraulic excavator performed by applying a 3D vision system,3D information control system, a safety system, a 3D measurement system,and an operator interface communication system.As a result of the verification of the excavation motion suggest the technical possibility of achieving autonomous robotic excavation in moving toward construction automation.

Abstract: Hydraulic excavator energy-saving is important to relieve source shortage and protect environment. This paper mainly discusses the energy saving for the hybrid hydraulic excavator. By analyzing the excess energy of three hydraulic cylinders in the conventional hydraulic excavator, a new boom potential energy recovery system is proposed. At last, the model of the proposed system has been built by AMESim. The simulation result shows that the proposed boom potential energy recovery system has a high energy saving efficiency.