Demolition Robot Research Articles

A compound planning algorithm considering both collision detection and obstacle avoidance for intelligent demolition robots

This paper presents a compound planning algorithm considering both collision detection and obstacle avoidance for intelligent demolition robots working safely in high-radiation environments. Firstly, configurations and kinematics of the intelligent demolition robot are detailed to detect the possible obstacles in its workspace. A collision detection function based on the improved dual vector method is proposed to detect the different distances between the robot and obstacles in three cases: a point and a line segment, two line segments, and a line segment and a geometric shape. This function can also be applied to detect collisions with various obstacles of different shapes reasonably and efficiently. Furthermore, an obstacle avoidance function based on modified gradient projection method considering multi-task transformation is proposed. According to the different distances between the robot and the obstacle, it can be used in three situations: end obstacle avoidance task, end effector operation task, and end trajectory tracking task. This function can be applied to avoid obstacles both in the workspace and on the desired path. Finally, a simulation system is established to verify the collision detection and obstacle avoidance algorithms of the intelligent demolition robot. An experiment was conducted on the intelligent demolition robot. This robot can successfully achieve the expected trajectory with the method described in this article. Results of simulation and experiment demonstrate that obstacles both in workspace and on desired path can be detected and avoided properly.

Enhancing Demolition Works Safety: Integrating Numerical and Experimental Methods for Structural Failure Prevention in Remote-Controlled Demolition Robots.

The paper presents an approach that combines numerical and experimental techniques to evaluate the possibility of failure prevention of the structure of demolition robots. Based on a real example of the machine, the possibility of application and development of the author's method was presented. The main problem when designing this type of machine is the negligible knowledge of how dynamic loads act during operation and how many times they appear. Underestimating the loads and their cycles when designing these types of machines can cause them to become damaged quickly. The method presented in the article allows to solve the problem of determining the key parameters needed in the evaluation of this type of construction such as loads, but also allows to determine the number of load cycles, which is particularly important for fatigue. The result presented in the article is an authors’ method that allows determining the fatigue of the structure of a demolition machine by combining numerical and experimental techniques.

Environmental Assessment of Demolition Tools Used in Townhouse Demolition: System Dynamics Modeling

To accommodate population growth and migration to cities, many infrastructures have been demolished to build new residential units. Demolition processes cause various environmental problems globally and locally. The selection of methods used in demolition is crucial to reduce the long-term environmental impact. This study considers various combination tools used in townhouse demolition in Thailand, examines their environmental impacts, and suggests the combination of the tools to be used in the long term. The system dynamics (SD) modeling approach is utilized in this study to capture the changes in townhouse units, sizes, demolition tools, demolition time, and the work rates of tools and their effects on the environment. This approach has the capability to model complex relationships and examine long-term trends. Secondary data are employed to identify variables necessary for SD model development, such as the different sizes of townhouses in Thailand, the various types of demolition tools used in the construction industry, and environmental impacts from building demolition. The simulation results revealed that Combination 4, i.e., the use of demolition robots and hydraulic splitters, is the most effective combination to reduce the final impact percentage in the long term. Compared with the other three combinations, it generates the lowest CO2eq emissions, energy consumption, noise, dust, and heat. If demolition robots are not yet available, Combination 1 (i.e., the use of excavators, jackhammers, and flame-cutters) offers the lowest environmental impact in the long term. This study provides guidelines for decision-makers in the construction industry to make sustainable choices of demolition tools and techniques used for townhouse demolition to reduce long-term environmental impacts.

Inverse kinematics solution of demolition manipulator based on global mapping

In solving the inverse kinematics of the redundant hydraulic manipulator of the demolition robot, there are problems of multiple solutions and the contradiction between the real-time and accuracy of the calculation. A series calculation strategy combining global mapping and local search was proposed. Firstly, the inverse kinematics solution was mapped from the global space to the local space of the working point by the global neural network model, and then the inverse solution results were obtained by the local search of the gravitational search algorithm. To avoid the GSA falling into the local minima and improve the search speed and accuracy, an improved gravitational particle adaptive step search strategy was proposed to balance the exploration and development stage of the population. The simulation and experimental results show that the global than local inverse solution algorithm can avoid the multi-solution problems and ensure the stability and accuracy of the solution on the basis of real-time inversion.

Participants matter: Effectiveness of VR-based training on the knowledge, trust in the robot, and self-efficacy of construction workers and university students

Virtual Reality (VR)-based training has gained attention from the scientific community in the Architecture, Engineering, and Construction (AEC) industry as a cost-effective and safe method that eliminates the safety risks that may impose on workers during the training compared to traditional training methods (e.g., in-person hands-on training, apprenticeship). Although researchers have developed VR-based training for construction workers, some have recruited students rather than workers to understand the effect of their VR-based training. However, students are different from construction workers in many ways, which can threaten the validity of such studies. Hence, research is needed to investigate the extent to which the findings of a VR-based training study are contingent on whether students or construction workers were used as the study sample. This paper strives to compare the effectiveness of VR-based training on university students’ and construction workers’ knowledge acquisition, trust in the robot, and robot operation self-efficacy in remote operation of a construction robot. Twenty-five construction workers and twenty-five graduate construction engineering students were recruited to complete a VR-based training for remote operating a demolition robot. We used quantitative analyses to answer our research questions. Our study shows that the results are dependent on the target sample in that students gained more knowledge, whereas construction workers gained more trust in the robot and more self-efficacy in robot operation. These findings suggest that the effectiveness of VR-based training on students may not necessarily associate with its effectiveness on construction workers.

Intelligent demolition robot: Structural statics, collision detection, and dynamic control

This paper presents a modified oriented bounding box method and a compound control law for the developed intelligent demolition robot working safely and accurately in a high-radiation environment. Combining statics and kinematics, the modified oriented bounding box method is applied to predict the real-time and accurate collision detection of possible collisions. The Newton–Euler method is then adopted to derive the dynamic model. A compound control law based on dynamic feedforward torque and proportional integral derivative feedback torque is established to achieve high-accuracy control. Furthermore, a simulation system and experiment prototype are developed to verify the functions of collision detection and dynamic control. Simulation results demonstrate that the modified oriented bounding box method predicts the collision detection properly. Compared with the traditional proportional integral derivative control law, experimental results demonstrate that the compound control law realizes higher tracking accuracy within 0.04 m for the intelligent demolition robot.

Effectiveness of VR-based training on improving construction workers’ knowledge, skills, and safety behavior in robotic teleoperation

The emergence of construction robotics and automation has produced an urgent and vast need for construction workers to reskill and upskill for the future of work. Virtual Reality (VR)-based training has been considered and investigated as a safe and cost-effective training method that allows workers to be exposed to hazardous tasks with negligible actual safety risks in comparison to existing training methods (hands-on, lecture-based, apprenticeship training). This paper aims to investigate the impact of VR-based training on construction workers’ knowledge acquisition, operational skills, and safety behavior during robotic teleoperation compared to the traditional in-person training method. Fifty construction workers were randomly assigned to complete either VR-based or in-person training for operating a demolition robot. We used quantitative and qualitative data analyses to answer our research questions. Our results indicate that VR-based training was associated with a significant increase in knowledge, operational skills, and safety behavior compared to in-person training. Our findings suggest that VR-based training not only provides a viable and effective option for future training programs but a valuable option for construction robotics safety and skill training.

Research on the Trajectory Planning of Demolition Robot Attachment Changing

The process of changing the attachment of a demolition robot is a complex operation and requires a high docking accuracy, so it is hard for operators to control this process remotely through the camera’s perspective. To solve this problem, this paper studies trajectory planning for changing a demolition robot attachment. This paper establishes a link parameter model of the demolition robot; the position and attitude of the attachment are obtained through a camera, the optimal docking point is calculated to minimize the distance error during angle alignment for attachment change, the inverse kinemics of the demolition robot are solved, the trajectory planning algorithm and visualization program are programmed, and then the trajectory planning for the demolition robot attachment changing method is proposed. The results of calculations and experiments show that the method in this paper can meet the accuracy, efficiency, and safety requirements of demolition robot attachment changing, and it has promising application prospects in the decommissioning and dismantling of nuclear facilities and other radioactive environments.

Research on variable mass control of series manipulator based on linear active disturbance rejection control

The series manipulator of the demolition robot has different working postures and large self-weight so that the bearing mass of the joint hydraulic cylinder is a variable value, and the change of mass affects the dynamic characteristics of the valve-controlled hydraulic cylinder system. In this paper, an equivalent mass estimation method of the big-arm joint hydraulic cylinder is given, and the natural frequency range of the big-arm hydraulic cylinder-load system is calculated. In order to suppress the influence of the change of the natural frequency and external disturbance of the hydraulic cylinder on the system, the linear active disturbance rejection control is adopted in the closed-loop position control. The simulation results show that the change of load mass of the joint hydraulic cannot be ignored when designing the joint position controller of multi-joint hydraulic manipulator. And the simulation tests prove that the linear active disturbance rejection control strategy keeps good dynamic characteristic and steady-state accuracy for the change of natural frequency and external disturbance of hydraulic cylinder and has good tracking performance for periodic sinusoidal signal. Linear active disturbance rejection control is robust in the variable mass control of the manipulator and meets the requirements of the joint position control of the heavy-duty hydraulic manipulator.

Inverse calculation of demolition robot based on gravitational search algorithm and differential evolution neural network

For the inverse calculation of laser-guided demolition robot, its global nonlinear mapping model from laser measuring point to joint cylinder stroke has been set up with an artificial neural network. Due to the contradiction between population diversity and convergence rate in the optimization of complex neural networks by using differential evolution, a gravitational search algorithm and differential evolution is proposed to accelerate the convergence rate of differential evolution population driven by gravity. Gravitational search algorithm and differential evolution is applied to optimize the inverse calculation neural network mapping model of demolition robot, and the algorithm simulation shows that gravity can effectively regulate the convergence process of differential evolution population. Compared with the standard differential evolution, the convergence speed and accuracy of gravitational search algorithm and differential evolution are significantly improved, which has better optimization stability. The calculation results show that the output accuracy of this gravitational and differential evolution neural network can meet the calculation requirements of the positioning control of demolition robot’s manipulator. The optimization using gravitational search algorithm and differential evolution is done with the connection weights of a neural network in this article, and as similar techniques can be applied to the other hyperparameter optimization problem. Moreover, such an inverse calculation method can provide a reference for the autonomous positioning of large hydraulic series manipulator, so as to improve the robotization level of construction machinery.

Research on Visualization and Error Compensation of Demolition Robot Attachment Changing.

Attachment changing in demolition robots has a high docking accuracy requirement, so it is hard for operators to control this process remotely through the perspective of a camera. To solve this problem, this study investigated positioning error and proposed a method of error compensation to achieve a highly precise attachment changing process. This study established a link parameter model for the demolition robot, measured the error in the attachment changing, introduced a reference coordinate system to solve the coordinate transformation from the dock spot of the robot’s quick-hitch equipment to the dock spot of the attachment, and realized error compensation. Through calculation and experimentation, it was shown that the error compensation method proposed in this study reduced the level of error in attachment changing from the centimeter to millimeter scale, thereby meeting the accuracy requirements for attachment changing. This method can be applied to the remote-controlled attachment changing process of demolition robots, which provides the basis for the subsequent automatic changing of attachments. This has the potential to be applied in nuclear facility decommissioning and dismantling, as well as other radioactive environments.

Energy Recovery Simulation Research of Demolition Robot Rotation Hydraulic System

When the robot rotates to brake, the oil circuit of the system will produce greater pressure impact due to the large moment of inertia. High pressure oil overflows through the relief valve, then the overflow back pressure provides negative torque to brake the turntable. The rotational kinetic energy is finally dissipated in the form of heat energy, resulting in the waste of energy and the increase of oil temperature as well as the decline of system performance. Therefore, a scheme of recovery and utilization of rotary kinetic energy is proposed, that is, to recover the kinetic energy of the turntable during the rotary braking and to use the recovered energy as auxiliary energy during the rotary start-up. Virtual.Lab-Motion and AMESim are used to establish the joint simulation model of the electromechanical and hydraulic system of the demolition robot. The simulation results show that the energy recovery efficiency of the scheme can reach over 65%, and the comprehensive energy saving efficiency can reach about 10%.

Design and analysis of demolition robot arm based on finite element method

As a novel robot which mainly engages in the demolition and transformation of various concrete buildings, the demolition robot has developed rapidly in recent years. The impact force is mainly produced by the breaking hammer installed in the front end of the arm. As the most important part of a demolition robot, the boom arm is mainly composed of four parts including a supporting arm, a main arm, a fore arm, and a breaking hammer system. In this article, a mechanical model of the boom arm is established, and the finite element analysis obtaining the first four-order natural frequencies and modes is carried out in ANSYS Workbench. The results reveal that the resonation can be easily stimulated when a hydraulic breaking hammer is at the second-order frequency. The mounting block of the hydraulic breaking hammer, the hinge parts of the supporting arm, and the main arm are easily deformed or damaged in the Y direction by analyzing the deformation in three directions of the second-order mode. After the structure optimization, the vibration characteristics of the two parts are significantly enhanced, which provides a theoretical basis for optimizing the prototype and gives a reference in the experimental modes.

Application of a Design and Construction Method Based on a Study of User Needs in the Prevention of Accidents Involving Operators of Demolition Robots

The paper presents a new method of design and construction aimed at developing a system that helps to prevent accidents involving demolition robot operators. The method is based on a study of user needs and was developed in accordance with Design Thinking methodology. This study provides a theoretical review of designing processes and methodologies, including conceptual design, and explores the implementation of the proposed method in the designing process for a Human–Machine Interface (HMI) accident prevention system. An in-depth study of user needs combined with an analysis of the operational system, both of which followed the stages in the proposed method, as well as with experimental tests on a small remote control demolition robot, inspired the development of an operator-controlled HMI system. The theoretical review concerns non-haptic feedback devices, which can be implemented in the demolition robot remote control or in operator safety equipment. Experimental research helped to determine the data necessary to develop an HMI system that continuously uses information from sensors installed on the machine. The paper also addresses issues related to the implementation of the HMI interface in order to avoid failures resulting from robot misuse and to protect the operator from any hazards caused by potential accidents. This paper emphasizes the importance of the connection between man and machine to overcome the lack of direct information flow in the case of mechanical operation.

Hydraulic System Modeling and Motion Control of Demotion Robots Working Equipment

Based on the electro-hydraulic proportional system of a demolition robot working device, a simplified mathematical model was established by analyzing dynamic characteristics of the electro-hydraulic proportional valve, flow equation, the continuity equation and force equilibrium equations, and the fuzzy self-adaptive PID controller was designed to realize position control of working equipment. The simulations reveal that, compared with traditional PID, the fuzzy self-adaptive PID controller has these advantages such as smaller overshoot, good dynamic response and steady state performance.

Kinematics Simulation and Design of Work Elements of Demolition Robot Based on Virtual Prototype

Work Scope is key performance to the Demolition robot and is also a major factor consider to the users. CATIA and ADAMS were employed to design the 3D model and do the kinematics simulation to complete the design of work element of Demolition Robot. Parameters of assembly and interference detection of the 3D model was checked in the CATIA before taking the kinematics simulation experiment. The simulated result indicated that maximum radius, maximum depth and maximum height of Demolition Robot could be obtained, variance of forces at key articulated points and scope of work envelope diagram were presented, which provides a new method to analyze and design Demolition Robot.

2P1-B23 ID-tag based information system for a building demolition robot.

2P1-B23 ID-tag based information system for a building demolition robot.