Control Of Boom Research Articles

MPC motion control of boom descending of unmanned excavator based on regenerative valve

The control precision of the working device has always been a challenging aspect in unmanned excavator research due to the adoption of a triangular drive mode and a complex hydraulic system in the working mechanism. The article focuses on the research of autonomous control for the downward motion of a robotic arm in an unmanned excavator equipped with a regeneration valve. The study aims to achieve precise tracking of fast movement trajectories during operator manipulation, utilizing Model Predictive Control (MPC). Furthermore, the exceptional disturbance rejection capability of the MPC algorithm is demonstrated through interference application. A comprehensive model considering mechanical, hydraulic, and electrical factors is established for the excavator boom. The MPC algorithm is applied to achieve precise control over the boom descent process, providing a foundation for motion control in unmanned excavators. This article presents a theoretical analysis to elucidate the robustness principle of MPC in the descent control of uncertain dynamic arms. By incorporating real parameters, we successfully track predetermined planned paths at different speeds and validate them on a 20-ton hydraulic excavator. The results demonstrate that the MPC control algorithm accurately manipulates the boom descent motion while exhibiting excellent disturbance rejection performance. Compared to PID control algorithms, MPC offers wider target adaptability range and better disturbance rejection performance, making it suitable for rapid application in controlling working devices of unmanned excavators.

Simulation and experiment on obstacle avoidance control of concrete pump truck boom based on improved danger field and gradient projection method

Aiming at the shortcomings of the traditional robot obstacle avoidance algorithm applied directly to the leader–follower task transformation of concrete pump truck boom, an algorithm combined with improved danger field and improved gradient projection method for obstacle avoidance control of the boom is proposed. In the method, a joint limit avoidance function is used to avoid the angle overrun of the boom joints. And the danger field expression is modified to improve its engineering suitability. Moreover, a smoothing adjustment factor is introduced to improve the smoothness of the leader–follower task transformation of the boom. The influence of key control parameters on the safety and accuracy of boom movement is discussed through the simulation, and the reasonable ranges of the parameters are given. Furthermore, experiments are carried out to verify the effectiveness of the algorithm. The method provides a solution for obstacle avoidance control of construction machinery with multijoint series boom.

Fast luffing control of flexible boom of mobile elevated work platform with uncertain control input gain

In this paper, the dynamic model between input electric signal of hydraulic valve and boom luffing angle is established, and luffing control of flexible boom of mobile elevated work platform (MEWP) is studied. The control input gain for the luffing motion of the MEWP is extremely difficult to solve and varies with boom length, work platform load, and luffing angle. For the variable control input gain, all low-order state quantities, rigid-flexible coupling quantity, and control input are included as the “total disturbance” to be observed. Based on the third-order linear tracking differentiator and the first-order ordinary differential linear equation, an active disturbance rejection controller without control input gain is proposed. With the bandwidth-based parameter settings, the controller only needs to adjust two parameters. As a comparison, this paper analyzes in detail the proposed controllers, the fixed input gain active disturbance rejection controller and the PID controller in terms of tracking error, overshoot, setting time, tracking stability, and robustness.

Studies of behaviour of the automatic control system of roadheader cutting heads movement

Boom–type roadheaders are basic machines used in underground mines for drilling roadways, in tunnelling and also for making underground buildings using trenchless methods. The article presents selected results of tests carried out in a semi–industrial scale, on a roadheader R–130, concerning behaviour of an innovative solution of system for automatic control of boom–type roadheader cutting heads’ movements. This important innovation, not known before in mining cutting machines, is the software control of cutting heads angular speed using a frequency converter. The text shows an impact of key values, from a perspective of an assumed control purpose, of programming device (setting system) parameters, achieving reference values for the actuators, on controlled facility behaviour when cutting a layered cement and sand block. The performance of the automatic control system without and with feedback to the setting system concerning an actual speed of cutting heads movement, which is important from the control system hardware perspective, was compared.

Combined motion control of hydraulic boom based on dynamic surface adaptive fuzzy sliding mode

The lifting mechanism on the transfer vehicle is a common electromechanical–hydraulic system. In order to overcome the non-linear and interference that exist in the hydraulic boom combined motion process, a dynamic surface adaptive fuzzy sliding mode control method is proposed. The Lyapunov function and virtual control base on inversion of the sliding mode control are designed, the dynamic surface control is used to calculate the derivative of the virtual control, and the adaptive control is applied to estimate the parameter. Furthermore, the fuzzy control is applied to fuzzification the switching item of the sliding surface. Verified by simulation, the designed sliding mode controller has high control accuracy and strong robustness and eliminates system chatter.

Aerodynamic analysis and elastic suppression of refueling boom

This paper studies on the refueling boom aerodynamic characteristics and proposes an elastic suppression method for the refueling boom with the property of large length-diameter ratio. In order to obtain the accurate frequency response, modal analysis for the refueling boom is conducted based on ANSYS MODAL. Then the dynamics and kinematic equations of the elastic refueling boom are deduced, which contain the frequency parameter. To complete the equations, the aerodynamic performance is solved in ANSYS FLUENT. In addition, based on the mixed H2 / H ∞  theory, an optimal PID controller is proposed to suppress the elastic deformation. Furthermore, the parameters of the PID controller are optimized with the differential evolution algorithm. Simulation shows that the different elastic mode has different effect on the control of the refueling boom. The elastic deformation is suppressed obviously for each mode.

Effects of Specific Banking Factors on Credit Risk of Vietnam’s Commercial Banks

Applying OLS approach, the paper aims at identifying specific banking factors which impact on credit risk of Vietnam’s comercial banks. Using data collected from financial statements of 32 Vietnam’s commercial banks in the years 2010–2013 and the application of OLS, three idendified factors comprise loan growth, size, and cost-income-ratio. Based on the research findings, several recommendations are proposed for individual investors, further contributing to prompt awareness of the factors with negative effects on credit risk and proper control of lending boom impacts.

Dynamics and robust adaptive control of a deployable boom for a space probe

Various spacecraft missions have driven the need for lighter, stronger deployable structures, which help to hold instruments, such as a magnetometer, away from the spacecraft to avoid the disturbance caused by remanence of the spacecraft body. In this paper, we will present a type of deployable boom for small spacecraft, which is characterised by a small stowed volume, light weight and a large magnification ratio. Because the actual parameters of the deployable boom are all nonlinear, modelling of the boom becomes a key point. Considering the uncertainties in the model parameters, an approximate dynamic model with uncertain parameters is formulated by classifying the uncertainties into different types, including constant parametric, variable parametric and nonparametric uncertainties. Then, a robust adaptive control strategy is proposed to compensate for or reject these uncertainties separately; a feed-forward and feedback controller is designed to reduce the errors between the desired and the real trajectories, an adaptive controller aims at compensating for constant parametric uncertainties and a robust controller is used to reject the variable parametric and nonparametric model uncertainties. Thus, a robust adaptive control strategy does not rely on the exact dynamic model and can completely compensate for or reject the effect of model uncertainties. Finally, the simulation results show that the proposed control law is perfectly adequate for the deployable boom.

Trajectory Optimization Method for Follow-Up Control of Concrete Pump Truck

The follow-up control of concrete pump truck is in order to solve the problem that whole boom follows the movement of boom end under the artificial traction. Focus on real-time detection of boom end azimuth change and inverse kinematic problems of redundant boom system, two-axis gravitational accelerometer is used to detect azimuthal variation of boom end, and the best motion trajectory of boom is determined by solving constrained nonlinear optimization function which takes minimum displacement distance of barycentre for the whole boom as the optimization goal. At last, relative azimuth and translation of boom end, rotation of boom are solved together to make translation and rotation of boom being synchronization. In this way to ensure whole boom follows the artificial traction in theory. In order to verify the discussion above, matlab is used to simulate several different working conditions for the follow-up control of boom.

Interval Type-2 fuzzy position control of electro-hydraulic actuated robotic excavator

This paper deals with fuzzy intelligent position control of electro-hydraulic activated robotic excavator for the control of boom, arm and bucket axes. Intelligent control systems are required to overcome undesirable stick–slip motion, limit cycles and oscillations. Models of electro-hydraulic servo controlled front end loader excavators are highly nonlinear. The nonlinear model accounts for fluid flow rate of valve, pump hydraulics, and friction forces. The friction forces are modelled by Coulomb, viscous and Stribeck function. Interval Type-2 Fuzzy Logic Controller (IT2FLC) is used to study the time-domain position responses of axes in the presence of external applied load. It has the ability to control the position of each of the three axes with minimum actuator position errors. Models presented are accurate and study the dynamics of the actuator and load. To improve the transient behaviour of the robotic excavator, we eliminated jitter of the bucket movement in the presence of nonlinearities.

Control of a Space Rigidizable Inflatable Boom Using Macro-fiber Composite Actuators

An experimental investigation of vibration testing and active control of a space rigidizable inflatable composite boom containing embedded piezoelectric composite actuators was conducted. Inflatable deployable space structures offer reduced mass, higher packaging efficiency, lower life cycle cost, simpler design with fewer parts, and higher deployment reliability for many large deployable spacecraft structures applications. Enhancing deployed precision and repeatability for these structures is an ongoing research area, in particular for rigidizable inflatable material systems. In this study, in situ vibration testing and active damping using piezoelectric macro-fiber composite actuators embedded within a typical space-rigidizable deployable composite boom are investigated The embedded macro-fiber composites are shown to be capable of surviving integration, packaging, deployment and thermal rigidization in vacuum, and subsequently operating at their full actuation capability. Positive position feedback controllers using accelerometer, laser vibrometer, and strain gage feedback signals are designed and experimentally evaluated. Velocity-proportional and acceleration-proportional controllers are shown to be capable of attenuating fundamental bending response significantly using only modest control authority (—23dB with 10% of available voltage).

Harvesting potatoes into water in a water-tight truck bed

This study was undertaken to evaluate the effects of harvesting potatoes into water on tuber injury and to determine if the operation was commercially feasible. It was found that tubers harvested into water had fewer and lighter colored blackspots than tubers harvested into conventional flat-bed or chain-conveyor bulk potato trucks. Harvesting into water also reduced external tuber injury demonstrating that truck beds may not need elaborate padding. Some problems of operation in the field were minimized, particularly the need to closely synchronize tractor and truck speeds when building loads, and the close control of the loading boom with respect to the truck bed as the truck or harvester bounced over unavoidable obstacles in the field. Potatoes were partially pre-washed during the handling operation. Unloading potatoes with water at the packing house, in addition to reducing injury, eliminated the need for moving parts such as conveyors or hoists for discharging tubers, indicating that initial purchase costs of truck beds as well as maintenance costs would be reduced.