Excavator Arm Research Articles

MODELLING AND 3D PRINTING OF JCB ARM

The Hydraulic excavator machines are heavy duty earth movers consisting of a boom, arm and bucket. It works on principle of hydraulic fluid with hydraulic cylinder and hydraulic motors. The Hydraulic excavator arm operation require coordinated movement of boom, arm and bucket. The important criteria for the design to be safe is that, the digging forces developed by actuators must be greater than that of the resistive forces offered by the surface to be excavated. The main objective of this paper is to perform design and analysis Excavator Arm for the calculated Force. The CATIA software is used for making the 3D model of the excavator arm linkage. By using ANSYS workbench software analysis of the excavator arm is done at existing digging force and lifting force. Excavator bucket is very crucial element of hydraulic excavator. The whole loads of excavated materials have been carried out by this element. As the present mechanism used in excavator arm is subjected to deformation and bending stresses during lifting and digging operation respectively, because of which failure occurs frequently at the bucket end of the arm. Keywords: Excavator arm, Digging force, CATIA, ANSYS 16.0.

Research on drilling hole sequence planning based on a double-arm drilling machine

Based on the integrated structure characteristics of the double-arm drilling machine, there are two kinds of interference between drilling and excavation operations. Through the simplified calculation of the structure model of the left and right drilling arms, the drilling range of the double-arm drilling and loading machine is obtained. Through the calculation of the structure model of the excavation arm, the excavation range is obtained. The interference area and pure interference area exist in the operation range of the three working arms. Taking the drilling arrangement of the section of the 2556 north wing transport lane in Xinji No.1 Mine as an example, the drilling hole sequence to avoid interference is planned for the 52 drilling holes in the drilling range and interference range of the left and right drilling arms, which solves the operation interference of the three working arms and plans two optimal drilling hole sequences. It provides a reference for the subsequent industrial application of various types of drilling machines in coal mines.

A REVIEW PAPER ON MODELLING AND 3D PRINTING OF JCB ARM

The Hydraulic excavator machines are heavy duty earth movers consisting of a boom, arm and bucket. It works on principle of hydraulic fluid with hydraulic cylinder and hydraulic motors. The Hydraulic excavator arm operation require coordinated movement of boom, arm and bucket. The important criteria for the design to be safe is that, the digging forces developed by actuators must be greater than that of the resistive forces offered by the surface to be excavated. The main objective of this paper is to perform design and analysis Excavator Arm for the calculated Force. The CATIA software is used for making the 3D model of the excavator arm linkage. By using ANSYS workbench software analysis of the excavator arm is done at existing digging force and lifting force. Excavator bucket is very crucial element of hydraulic excavator. The whole loads of excavated materials have been carried out by this element. As the present mechanism used in excavator arm is subjected to deformation and bending stresses during lifting and digging operation respectively, because of which failure occurs frequently at the bucket end of the arm. Keywords: Excavator arm, Digging force, CATIA, ANSYS 16.0.

Analysis of Vibration Characteristics of Hydraulic Excavator Device Under Flat Ground Conditions

Hydraulic excavators, characterized by their high efficiency and versatility, are crucial equipment in engineering construction. During the automatic excavation process, the excavator may experience resonance phenomena, which can affect the stability of the entire system. In order to study the vibration harmonic response of the excavator arm in the process of reciprocating motion, firstly, the model of the excavator arm is designed in three‐dimensional software, and the finite element meshing software is used to perform hexahedral meshing of the excavator arm model and define the material properties. Secondly, the modal analysis of the excavator arm is carried out by finite element simulation software, and the displacement and acceleration harmonic response analysis is carried out using the modal superposition method. Finally, the vibration experiment of reciprocating motion with different frequencies is carried out on the experimental platform of the excavator arm. The simulation and experimental results show that the maximum value of the displacement and acceleration response of the excavator arm corresponds to the frequency near the second‐order intrinsic frequency, and the excavator arm is greatly affected by the second‐order intrinsic frequency; controlling the frequency of the reciprocating motion of the hydraulic cylinder within 13 Hz can effectively avoid the resonance phenomenon of the excavator arm device.

OPTIMIZAREA ȘI INTEGRAREA ACTUATORILOR ELECTROMECANICI ÎN BRAȚELE EXCAVATOARELOR AGRICOLE PENTRU EFICIENȚĂ ÎMBUNĂTĂȚITĂ ȘI LONGEVITATE A ACUMULATORILOR

The research optimizes electric consumption in agricultural excavator booms by integrating electromechanical actuators and Power-by-Wire technologies. Utilizing a PID controller reduces electric motor peak current consumption, enhancing battery longevity. The research, carried out on a reduced-scale experimental stand, reveals the potential applications of the excavator arm equipment in agriculture, such as the precise location of irrigation systems, arrangement of terraces for orchards or vineyards, setting up greenhouses, and efficient unloading/loading of bulk materials. These applications signify the versatility and adaptability of electrically powered excavators in addressing diverse agricultural needs, emphasizing the significance of the developed mechatronic system for enhancing efficiency and sustainability in agricultural practices.

Potential Energy Recovery and Direct Reuse System of Hydraulic Hybrid Excavators Based on the Digital Pump

The potential energy recovery of hydraulic excavators is very significant for improving energy efficiency and reducing pollutant emissions. However, the more common solutions for potential energy recovery require more energy conversion processes before these potential energies can be reused, which adds to the complexity and high cost of the system. To tackle the above challenges, we proposed a novel energy recovery system for hydraulic hybrid excavators based on the digital pump with an energy recovery function. The new system could operate in three different modes: pump, energy recovery, and direct reuse. Based on the descriptions of the working principle of the digital pump and the whole energy recovery system, the mathematical models of the digital pump, the excavator arm cylinder, and the accumulator were established and the AMESim simulation model (combining mechanics, hydraulics, and electrics) was developed. The dynamic characteristics of the energy recovery system were studied under no-load and full-load conditions. The simulation results showed that this scheme could achieve 86% energy recovery when the boom was lowered and reused the recovered energy directly when raised, which could decrease the system input energy by 78.1%. This paper can provide an optimized solution for construction machinery or off-road vehicles and presents a reference for the research on digital hydraulics.

Excavation pits—progress estimation and cause of delay identification

This work presents a method for automated excavation speed and progress estimation. First, a measure for the progress speed of an excavation pit is taken from the literature and evaluated regarding the possibility of automation. For each possible parameter, an automated extraction algorithm is presented. The used system is an autonomous excavator arm of a backhoe loader where the used hardware and software system is described. An experimental evaluation of the presented approach has been done with the autonomous system for a small trench, including multiple digging cycles. The resulting measurements seem to include some systematic errors which could be identified and suitable sanity checks could be implemented, removing the erroneous measurements. The remaining measurements were used to determine the excavation speed of the autonomous excavator arm and compared to the values of experienced and amateur operators. The resulting speed and the relevant parameters are then sent to a web application called “DiBa” to notice a potential delay. If a measurement is smaller or larger than expected a fault identification is done in the DiBa.

UV and IR dual light triggered cellulose-based invisible actuators with high sensitivity

Actuators are widely used in bionic devices and soft robots, among which invisible actuators have some unique applications, including performing secret missions. In this paper, highly visible transparent cellulose-based UV-absorbing films were prepared by dissolving cellulose raw materials using N-methylmorpholine-N-oxide (NMMO) and using ZnO nanoparticles as UV absorbers. Furthermore, transparent actuator was fabricated by growing highly transparent and hydrophobic polytetrafluoroethylene (PTFE) film on regenerated cellulose (RC)-ZnO composite film. In addition to its sensitive response to Infrared (IR) light, the as-prepared actuator also shows a highly sensitive response to UV light, which is attributed to the strong absorption of UV light by ZnO NPs. Thanks to the drastic differences in adsorption capacity between the RC-ZnO and PTFE materials for water molecules, the asymmetrically- assembled actuator demonstrates extremely high sensitivity and excellent actuation performance, with a force density of 60.5, a maximum bending curvature of 3.0 cm−1, and a response time of below 8 s. Bionic bug, smart door and the arm of excavator made from the actuator all exhibit sensitive responses to UV and IR lights.

Fatigue Analysis and Design Optimization of Excavator Bucket

Construction activity is continually rising, and the strong performance of construction equipment ensures rapid expansion in the earth moving machine sectors. This study focuses on the method for calculating the digging forces needed to dig the terrene for minor building work. This approach calculates the force and is also used to perform a fatigue analysis to determine the bucket's fatigue life and failure rate. Because the current excavator arm mechanism is subjected to deformation and bending forces during lifting and digging operations, failure at the bucket end of the arm happens frequently. The excavator arm is analysed using ANSYS workbench software at current digging force and lifting capacity. An analytical approach has also been provided for static force analysis of excavator bucket.

OPTIMIZATION OF THE HYDRAULIC SYSTEM IN THE EXCAVATOR ARM SIMULATOR

Most of the heavy equipment units use a hydraulic system, even including systems that are essential for working with a heavy equipment unit. The hydraulic system is a system that utilizes a liquid medium in the form of fluid or oil to generate pressure, which is used to implement, the power train system, the disconnection system, the steering system. The working principle of hydraulics is to utilize the pressure exerted on the tool (which is used for this actuator / cylinder / tube) so that the pressure pushes the piston which is connected to the rod. The hydraulic system in this study is an arm excavator. This simulator is like a hydraulic system in general which consists of a power unit, in this simulator the power unit used is a type of electric motor that is connected to a hydraulic pump. The control unit is in the form of a control valve. The drive unit is an actuator / cylinder / tube. This simulator has been disabled for a long time due to a malfunction. Then the authors performed a simple analysis and improvements to the excavator arm simulator. So the research that is done is to do the 8 step troubleshooting method on the simulator. This step aims to facilitate the repair process in the simulator.

Vibration transmissibility suppression for hydraulic excavators in working conditions via multi-objective optimization

The mass variances of materials in buckets and the movements of excavation arms greatly impact powertrain vibration transmissibility in hydraulic excavators under working conditions. If the influence of mass variation among bucket contents and excavation arm motions on vibration transmissibility is not considered, then only limited improvements can be made to vibration isolation performance. In this paper, vibration transmissibility suppression for hydraulic excavators operating under working conditions were studied via multi-objective optimization for stiffness coefficients of suspension elements (SEs). First, the rigid-flexible coupling model of a hydraulic excavator with a flexible base was built using ADAMS software. In the model, the stiffness coefficients of the SEs were the targeted variables with constrained conditions, while the multi-objectives for optimization were the vibration transmissibility and energy decoupling rates of the powertrain. Vibration isolation transmissibility (VIT) of the mounting system was compared between situations with non-optimized and optimized stiffness coefficients. Finally, the amplitude changes of the resultant SE support forces were used to illustrate the effects of powertrain vibration transmissibility suppression. We found that the average value of VITs increases significantly during the optimization process for the stiffness coefficients of SEs, which indicates that the mounting system has better vibration isolation performance. The smaller amplitudes of the resultant support force illustrate the improvements to the performance of vibration transmissibility suppression of the powertrain via the optimization process.

Dynamic Analysis of Excavator Arm Used for Breaking Operation

So far excavator retrofitting breaking hammer is commonly applied to impact breaking operation on rock, mountain and building body in engineering field. In practical operation fracture of the movable excavator arm frequently occurs. This thesis, in terms of dynamics, considers the breaking machine under three typical working conditions and aims at respective load solutions for the hinge point of the movable arm under each working condition. Modal analysis and harmonic response for the movable arm is conducted by means of finite element software. Analysis shows that the movable arm would not resonate at relatively high frequencies and external excitation load affects the movable arm noticeably at low frequencies. Damping increase of the working device of the breaking machine is needed to enable the external excitation frequency to avoid the primary and secondary inherent frequencies, and thus reduce the resonation opportunity of the movable arm.

Recurrent Neural Network-based Path Planning for an Excavator Arm under Varying Environment

This paper proposes an algorithm to generate the reference trajectory based on recurrent neural networks for an excavator arm working in a dynamic environment. Firstly, the dynamic of the plant which includes the tracking controller, the arm, and the pile is appropriated by a recurrent neural network. Next, the recurrent neural network combined with a Model Reference Adaptive Controller (MRAC) is used to calculate the reference trajectory for the system. In this paper, the generated trajectory is changed depending on the variation of the pile to maximize the dug weight. This algorithm is simple but effective because it only needs information about the weight at each duty cycle of the excavator. The efficiency of the overall system is verified through simulations. The results show that the proposed scheme gives a good performance, i.e. the dug weight always remains at the desired value (nominal load) as the pile changes its shape during working time.

Helical shape linen artificial muscles responsive to water

Artificial muscles, as the name suggests, can generate contractile force and movement from another source of energy in response to an external stimulus. Moisture-responsive artificial muscles can be manufactured from commodity natural fibers for smart textile applications taking advantage of the anisotropy, low cost and skin comfort of these fibers. Here we prepared water-driven artificial muscles by twisting linen yarns into spring-like cylindrical coils. Structural evolution, including increase in diameter and decrease in length of coils, is identified as a key factor to the actuation performances of the as-fabricated muscles. Artificial muscles with a single helical configuration can generate a large, reversible contraction stroke of about 22.5% and a high gravimetric work capacity during contraction of about 110 J kg−1 work capacity, which is many times greater than animal skeletal muscles and many synthetic fiber muscles. A torque-balanced double-helix muscle was constructed from the single helical muscle. The double helix showed good reversibility and high retention of contraction stroke (∼16.5%) in cyclic actuation tests. Finally, the as-fabricated water-responsive artificial muscles were used as manipulator arm of a miniature excavator.

HEAP - The autonomous walking excavator

The demand and the potential for automation in the construction sector is unmatched, particularly for increasing environmental sustainability, improving worker safety and reducing labor shortages. We have developed an autonomous walking excavator - based one of the most versatile machines found on construction sites - as one way to begin fulfilling this potential. This article describes the process of converting an off-the-shelf construction machine into an autonomous robotic system. First we outline the necessary sensing equipment for full autonomy and the novel actuation of the legs, and compare three different complementary actuation principles for the excavator's arm. Second, we solve the state estimation problem for a general wheeled-legged robot. Beside kinematic measurements, it includes GNSS-RTK, to absolutely reference the machine on a construction site. Third, we developed individual controllers for driving, chassis balancing and arm motions allowing for fully autonomous operation. Lastly, we highlight the machine's potential in four different real-world applications, e.g. autonomous trench digging, autonomous assembly of dry stone walls, autonomous forestry work and semi-autonomous teleoperation. On top, we also share some development insights and possible future research directions.

Dynamic Improvement of Hydraulic Excavator Using Pressure Feedback and Gain Scheduled Model Predictive Control

This work focuses on a gain scheduled Model Predictive Controller (MPC) for the dynamic performance enhancement of an excavator boom. The method can be generalized and applied to similar machines with the installation of pressure and boom angle transducers without modifying the hydraulic circuit of the system. In the proposed method, the transient part of pressure signals is isolated and used to counteract the actuator vibrations through a valve-based compensator. A full-scale model of an excavator's arm has been used for the experimental verification of the proposed approach. The experiments are conducted under various conditions with the proposed controller and compared with the conventional system. Since the stability of these types of machines is extremely important from the safety point of view, a stability analysis has been carried out and closed-loop stability of the system is ensured with the proposed controller. A significant reduction of 58% and 41% have been achieved in the cost function under maximum velocity extension and lowering phase respectively, where maximum boom oscillations are observed. Furthermore, an average vibration reduction of 46 % is obtained using the proposed method.

Connectivity Calculation-Based Automatic Synthesis of Planar Multi-Loop Mechanisms

AbstractThe creative design of kinematic structures with excellent performance remains an open issue in the quest for developing novel multi-loop mechanisms. This study presents an automatic method to synthesize all nonisomorphic planar multi-loop mechanisms satisfying the required connectivity between the base and the end-effector. First, based on the connectivity matrix calculation, all multi-loop mechanisms are generated from synthesized kinematic chains. Second, the concepts of perimeter, canonical, and characteristic graphs of multi-color topological graphs are addressed to acquire the simplified characteristic hybrid code (SCHC) in order to eliminate isomorphic multi-loop mechanisms. Then, an automatic method to synthesize all nonisomorphic planar multi-loop mechanisms with the required connectivity between the base and the end-effector is provided. Finally, a practical application of this synthesis method is illustrated by taking the mechanical arm of a face-shovel hydraulic excavator as an example to demonstrate the effectiveness of the method.

Path Planning for Excavator Arm: Fuzzy Logic Control Approach

This paper proposes an algorithm to design the path for automated excavator arm. The path designing is divided into two phases. Firstly, the fuzzy logic technique is used to determine the change of the path to adapt with the variation of the material after each digging period. Secondly, the B-spline algorithm is used to build the optimal trajectory. By this, the excavator can maximize the dug weight although the shape of the material is variation. The effectiveness of the algorithm is verified through computer simulation and real-time experiment. The simulation and experimental results show that the generated optimal path keeps the dug weight around the expected value regardless of the change of the environment.

Configuration Optimization for End-Point Stabilization of Redundant Manipulators With Base Flexibility

Abstract This paper presents a method to determine an optimal configuration of a teleoperated excavator to minimize the induced undercarriage oscillation for robust end-point stabilization. Treating the excavator as a kinematically redundant system, where non-unique combinations of the undercarriage position and arm posture can locate the end-point at the same reference. A specific configuration can be chosen to not excite undercarriage oscillation with simple end-point error feedback control without model-based or measurement-based vibration suppression. Robust stability measures based on normalized coprime factorization as well as modal decomposition solve the redundancy of the kinematics. An advantage of this approach is that the control engineer can proceed as if the excavator arm is fixed to rigid ground, which is practically not the case, and apply simple traditional Jacobian-based end-point control.

Robust Adaptive Controller Design for Excavator Arm

This paper presents a robust adaptive controller that does not depend on the system parameters for an excavator arm. Firstly, the model of the excavator arm is demonstrated in the Euler-Lagrange form considering with overall excavator system. Next, a robust adaptive controller has been constructed from information of state error. In this paper, the stability of overall system is mathematically proven by using Lyapunov stability theory. Also, the proposed controller is model free then the closed loop system is not affected by disturbances and uncertainties. Finally, the simulation is executed in Matlab/Simulink for both presented scheme and the PD controller under some conditions to ensure that the proposed algorithm given the good performances for all cases.