Showing papers in "Industrial Robot-an International Journal in 2017"

Exact laser beam positioning for measurement of vegetation vitality

Abstract: Purpose The purpose of this paper is to present a novel application for a newly developed Technical Vision System (TVS), which uses a laser scanner and dynamic triangulation, to determine the vitality of agriculture vegetation. This vision system, installed on an unmanned aerial vehicle, shall measure the reflected laser energy and thereby determine the normalized differenced vegetation index. Design/methodology/approach The newly developed TVS shall be installed on the front part of the unmanned aerial vehicle, to perform line-by-line scan in the vision system field-of-view. The TVS uses high-quality DC motors, instead of previously researched low-quality DC motors, to eliminate the existence of two mutually exclusive conditions, for exact positioning of a DC motor shaft. The use of high-quality DC motors reduces the positioning error after control. Findings Present paper emphasizes the exact laser beam positioning in the field-of-view of a TVS. By use of high-quality instead of low-quality DC motors, a significant reduced positioning time was achieved, maintaining the relative angular position error less than 1 per cent. Best results were achieved, by realizing a quasi-continuous control, using a high pulse-width modulated duty cycle resolution and a high execution frequency of the positioning algorithm. Originality/value The originality of present paper is represented by the novel application of the newly developed TVS in the field of agriculture. The vitality of vegetation shall be determined by measuring the reflected laser energy of a scanned agriculture zone. The paper’s main focus is on the exact laser beam positioning within the TVS field-of-view, using high-quality DC motors in closed-loop position control configuration.

An industrial security system for human-robot coexistence

Abstract: Purpose-The installation of industrial robots requires security barriers, a costly, time consuming exercise. Collaborative robots may offer a solution, however these systems only comply with safety standards if operating at reduced speeds. This paper describes the development and implementation of a novel security system that allows human robot coexistence while permitting the robot to execute much of its task at nominal speed. Design/methodology/approach-The security system is defined by three modes: a nominal mode, a coexistence mode and a gravity compensation mode. Mode transition is triggered by three lasers, two of which are mechanically linked to the robot. These scanners create a dynamic envelope around the robot and allow the detection of operator presence or environmental changes. To avoid velocity discontinuities between transitions we propose a novel time scaling method. Findings-The paper describes the system's mechanical, software and control architecture. The system is demonstrated experimentally on a collaborative robot and is compared with the performance of a state of art security system. Both a qualitative and quantitative analysis of the new system is carried out. Pratical Implications-The mode transition method is easily implemented, requires little computing power and leaves the trajectories unchanged. As velocity discontinuities are avoided, motor wear is reduced. The execution time is substantially less than a commercial alternative. These advantages can lead to economic benefits in high volume manufacturing environments. Originality/value-This paper proposes a novel system that is based on industrial material but that can generate dynamic safety zones for a collaborative robot.

Autonomous obstacle avoidance of an unmanned surface vehicle based on cooperative manoeuvring

Abstract: Purpose Autonomous obstacle avoidance is important in unmanned surface vehicle (USV) navigation. Although the result of obstacle detection is often inaccurate because of the inherent errors of LIDAR, conventional methods typically emphasize on a single obstacle-avoidance algorithm and neglect the limitation of sensors and safety in a local region. Conventional methods also fail in seamlessly integrating local and global obstacle avoidance algorithms. This paper aims to present a cooperative manoeuvring approach including both local and global obstacle avoidance. Design/methodology/approach The global algorithm used in our USV is the Artificial Potential Field-Ant Colony Optimization (APF-ACO) obstacle-avoidance algorithm, which plans a relative optimal path on the specified electronic map before the cruise of USV. The local algorithm is a multi-layer obstacle-avoidance framework based on a single LIDAR to present an efficient solution to USV path planning in the case of sensor errors and collision risks. When obstacles are within a layer, the USV uses a corresponding obstacle-avoidance algorithm. Then the USV moves towards the global direction according to fuzzy rules in the fuzzy layer. Findings The presented method offers a solution for obstacle avoidance in a complex environment. The USV follows the global trajectory planed by the APF-ACO algorithm. While, the USV can bypass current obstacle in the local region based on the multi-layer method effectively. This fact was validated by simulations and field trials. Originality/value The method presented in this paper takes advantage of algorithm integration that remedies errors of obstacle detection. Simulation and experiments were also conducted for performance evaluation.

A novel data glove using inertial and magnetic sensors for motion capture and robotic arm-hand teleoperation

Abstract: Purpose The purpose of this paper is to present a novel data glove which can capture the motion of the arm and hand by inertial and magnetic sensors. The proposed data glove is used to provide the information of the gestures and teleoperate the robotic arm-hand. Design/methodology/approach The data glove comprises 18 low-cost inertial and magnetic measurement units (IMMUs) which not only make up the drawbacks of traditional data glove that only captures the incomplete gesture information but also provide a novel scheme of the robotic arm-hand teleoperation. The IMMUs are compact and small enough to wear on the upper arm, forearm, palm and fingers. The calibration method is proposed to improve the accuracy of measurements of units, and the orientations of each IMMU are estimated by a two-step optimal filter. The kinematic models of the arm, hand and fingers are integrated into the entire system to capture the motion gesture. A positon algorithm is also deduced to compute the positions of fingertips. With the proposed data glove, the robotic arm-hand can be teleoperated by the human arm, palm and fingers, thus establishing a novel robotic arm-hand teleoperation scheme. Findings Experimental results show that the proposed data glove can accurately and fully capture the fine gesture. Using the proposed data glove as the multiple input device has also proved to be a suitable teleoperating robotic arm-hand system. Originality/value Integrated with 18 low-cost and miniature IMMUs, the proposed data glove can give more information of the gesture than existing devices. Meanwhile, the proposed algorithms for motion capture determine the superior results. Furthermore, the accurately captured gestures can efficiently facilitate a novel teleoperation scheme to teleoperate the robotic arm-hand.

Power line robotic device for overhead line inspection and maintenance

Abstract: Purpose This paper aims to focus on the design and testing of a robotic device for power line inspection and cleaning. The focus for this design is on simplicity and compactness with a goal to create a device for linemen and other power line workers to keep in their toolbox. Design/methodology/approach The prototype uses V-grooved wheels to grip the line and can pass obstacles such as splices. It is equipped with a video camera to aid in line inspection and a scrub brush to clean debris from the line. The operator controls the device remotely from a laptop through a wireless connection. The novel way in which this device moves down the power line allows compactness while still being able to overcome in-line obstacles up to a certain size. Findings The device has been tested on a test bed in the lab. The device is able to move down a line and expand to overcome in-line obstacles as it travels. Testing proved the mechanical feasibility and revealed new requirements for a future prototype. Practical implications The device can be used for power line asset management by power companies; line inspection can lead to preventative repairs, leading to less downtime. Social implications It stands to reduce costs related to maintenance and mitigates down time and emergency repairs. Originality/value Innovative features include its size, mobility and control methods. Overall, the impact of this work extends to the utility maintenance sector and beyond.

Tele-operated propeller-type climbing robot for inspection of petrochemical vessels

Abstract: The purpose of this paper is to propose a new propeller-type climbing robot called EJBot for climbing various types of structures that include significant obstacles, besides inspection of industrial vessels made of various materials, including non-ferromagnetic material. The inspection includes capturing images for important spots and measuring the wall thickness.,The design mainly consists of two coaxial upturned propellers mounted on a mobile robot with four standard wheels. A new hybrid actuation system that consists of propeller thrust forces and standard wheel torques is considered as the adhesion system for this climbing robot. This system generates the required adhesion force to support the robot on the climbed surfaces. Dynamic simulation using ADAMS is performed and ensures the success of this idea.,Experimental tests to check the EJBot’s capabilities of climbing different surfaces, such as smooth, rough, flat and cylindrical surfaces like the real vessel, are successfully carried out. In addition, the robot stops accurately on the climbed surface at any desired location for inspection purposes, and it overcomes significant obstacles up to 40 mm.,This proposed climbing robot is needed for petrochemical and liquid gas vessels, where a regular inspection of the welds and the wall thickness is required. The interaction between the human and these vessels is dangerous and not healthy due to the harmful environment inside these vessels.,This robot utilizes propeller thrusts and wheel torques simultaneously to generate adhesion and traction forces. Therefore, a versatile robot able to climb different kinds of structures is obtained.

Mechanism design of a biomimetic quadruped robot

Abstract: Purpose This paper aims to introduce a novel design of the biomimetic quadruped robot, including its body structure, three structural modes and respective workspace. Design/methodology/approach By taking a metamorphic 8-bar linkage as the body of a quadruped robot, the authors propose a reconfigurable walking robot that can imitate three kinds of animals: mammals (e.g. dog), arthropods (e.g. stick insect) and reptiles (e.g. lizard). Furthermore, to analyze the three structural modes of this quadruped robot, the workspace is calculated and studied. Findings Based on experimental data analyses, it is revealed that the metamorphic quadruped robot can walk in all its three structural modes and adapt to different terrains. Research limitations/implications Because the body of the quadruped robot is deformable and reconfigurable, the location of payload is not considered in the current stage. Practical implications The relative positions and postures of legs of the metamorphic robot can be rearranged during its body reconfiguration in such a way to combine all the features of locomotion of the three kinds of animals into one robot. So, the metamorphic quadruped robot is capable of maintaining wider stability margins than conventional rigid-body quadruped robots and conducting operations in different environments, particularly the extreme and restricted occasions due to the changeable and adaptable trunk. Originality/value The main contribution is the development of a reconfigurable biomimetic quadruped robot, which uses the metamorphic 8-bar linkage. This robot can easily reshape to three different structural modes and mimic the walking patterns of all mammals, arthropods and reptiles.

Paint thickness simulation for painting robot trajectory planning: a review

Abstract: Purpose The purposes of this paper are to review the progress of and conclude the trend for paint thickness simulation for painting robot trajectory planning. Design/methodology/approach This paper compares the explicit function-based method and computational fluid dynamics (CFD)-based method used for paint thickness simulation. Previous research is considered, and conclusions with the outlook are drawn. Findings The CFD-based paint deposition simulation is the trend for paint thickness simulation for painting robot trajectory planning. However, the calculation of paint thickness resulting from dynamically painting complex surface remains to be researched, which needs to build an appropriate CFD model, study approaches to dynamic painting simulation and investigate the simulation with continuously changing painting parameters. Originality/value This paper illustrates that the CFD-based method is the trend for the paint thickness simulation for painting robot trajectory planning. Current studies have been analyzed, and techniques of CFD modeling have also been summarized, which is vital for future study.

Pick-place of dynamic objects by robot manipulator based on deep learning and easy user interface teaching systems

Abstract: Development of autonomous robot manipulator for human-robot assembly tasks is a key component to reach high effectiveness. In such tasks, the robot real-time object recognition is crucial. In addition, the need for simple and safe teaching techniques need to be considered, because: small size robot manipulators’ presence in everyday life environments is increasing requiring non-expert operators to teach the robot; and in small size applications, the operator has to teach several different motions in a short time.,For object recognition, the authors propose a deep belief neural network (DBNN)-based approach. The captured camera image is used as the input of the DBNN. The DBNN extracts the object features in the intermediate layers. In addition, the authors developed three teaching systems which utilize iPhone; haptic; and Kinect devices.,The object recognition by DBNN is robust for real-time applications. The robot picks up the object required by the user and places it in the target location. Three developed teaching systems are easy to use by non-experienced subjects, and they show different performance in terms of time to complete the task and accuracy.,The proposed method can ease the use of robot manipulators helping non-experienced users completing different assembly tasks.,This work applies DBNN for object recognition and three intuitive systems for teaching robot manipulators.

A gesture-based telemanipulation control for a robotic arm with biofeedback-based grasp

Abstract: Purpose The idea is to exploit the natural stability and performance of the human arm during movement, execution and manipulation. The purpose of this paper is to remotely control a handling robot with a low cost but effective solution. Design/methodology/approach The developed approach is based on three different techniques to be able to ensure movement and pattern recognition of the operator’s arm as well as an effective control of the object manipulation task. In the first, the methodology works on the kinect-based gesture recognition of the operator’s arm. However, using only the vision-based approach for hand posture recognition cannot be the suitable solution mainly when the hand is occluded in such situations. The proposed approach supports the vision-based system by an electromyography (EMG)-based biofeedback system for posture recognition. Moreover, the novel approach appends to the vision system-based gesture control and the EMG-based posture recognition a force feedback to inform operator of the real grasping state. Findings The main finding is to have a robust method able to gesture-based control a robot manipulator during movement, manipulation and grasp. The proposed approach uses a real-time gesture control technique based on a kinect camera that can provide the exact position of each joint of the operator’s arm. The developed solution integrates also an EMG biofeedback and a force feedback in its control loop. In addition, the authors propose a high-friendly human-machine-interface (HMI) which allows user to control in real time a robotic arm. Robust trajectory tracking challenge has been solved by the implementation of the sliding mode controller. A fuzzy logic controller has been implemented to manage the grasping task based on the EMG signal. Experimental results have shown a high efficiency of the proposed approach. Research limitations/implications There are some constraints when applying the proposed method, such as the sensibility of the desired trajectory generated by the human arm even in case of random and unwanted movements. This can damage the manipulated object during the teleoperation process. In this case, such operator skills are highly required. Practical implications The developed control approach can be used in all applications, which require real-time human robot cooperation. Originality/value The main advantage of the developed approach is that it benefits at the same time of three various techniques: EMG biofeedback, vision-based system and haptic feedback. In such situation, using only vision-based approaches mainly for the hand postures recognition is not effective. Therefore, the recognition should be based on the biofeedback naturally generated by the muscles responsible of each posture. Moreover, the use of force sensor in closed-loop control scheme without operator intervention is ineffective in the special cases in which the manipulated objects vary in a wide range with different metallic characteristics. Therefore, the use of human-in-the-loop technique can imitate the natural human postures in the grasping task.

Integration of fault tree analysis, reliability block diagram and hazard decision tree for industrial robot reliability evaluation

Abstract: Purpose This paper aims to conduct a comprehensive fault tree analysis (FTA) on the critical components of industrial robots. This analysis is integrated with the reliability block diagram (RBD) approach to investigate the robot system reliability. Design/methodology/approach For practical implementation, a particular autonomous guided vehicle (AGV) system was first modeled. Then, FTA was adopted to model the causes of failures, enabling the probability of success to be determined. In addition, RBD was used to simplify the complex system of the AGV for reliability evaluation purpose. Findings Hazard decision tree (HDT) was configured to compute the hazards of each component and the whole AGV robot system. Through this research, a promising technical approach was established, allowing decision-makers to identify the critical components of AGVs along with their crucial hazard phases at the design stage. Originality/value As complex systems have become global and essential in today’s society, their reliable design and determination of their availability have turned into very important tasks for managers and engineers. Industrial robots are examples of these complex systems that are being increasingly used for intelligent transportation, production and distribution of materials in warehouses and automated production lines.

Cloud robotics: a review of technologies, developments and applications

Abstract: This paper aims to provide an insight into the current state of cloud robotics developments, technology and applications.,Following a short introduction, this paper first considers the potential benefits of cloud robotics. It discusses cloud service providers and then considers a range of recent applications and developments involving humanoid, mobile and industrial robots. This is followed by details of some recent market entrants and their developments. Finally, brief concluding comments are drawn.,Cloud robotics is a rapidly developing technology made possible by the current ubiquitous internet connectivity and the growing number of powerful cloud computing services available. Benefits include access to big data sets, open-source algorithms, code and programmes, massively powerful parallel or grid computing and the sharing of information between robots. The technology has been applied successfully to humanoid, industrial, mobile and other classes of robots, often through direct collaborations between robot manufacturers and major IT companies. Several new companies have been established in very recent years to exploit the capabilities of cloud robotic technologies.,Cloud robotics is a highly topical and rapidly developing field, and this paper provides a detailed insight into recent developments and applications.

Domestic robots: Has their time finally come?

Abstract: This paper aims to provide details of commercially available domestic robots and recent product developments and consider whether a significant boost in the robot population is imminent.,Following a short introduction, this paper first provides a brief overview of existing domestic robots and identifies recent product trends. It then discusses some newer product developments which extend the capabilities of domestic robots. This is followed by a consideration of the many recently launched companion robots, and the paper concludes with a discussion of the likely impact on the domestic robot market.,This paper shows that domestic robots have benefited from developments in artificial intelligence, sensor technology and connectivity, which have led to greater versatility and enhanced ease of use. Several new product developments are extending the range of functions conducted by domestic robots. Many small, mobile companion/social robots have recently been developed which interact with humans by speech and vision and conduct functions such as entertainment, the control of household appliances and security.,This paper provides an insight into the wide range of domestic robots which are available or under development and considers their commercial prospects.

Benchmarking motion planning algorithms for bin-picking applications

Abstract: For robot motion planning there exists a large number of different algorithms, each appropriate for a certain domain, and the right choice of planner depends on the specific use case. The purpose of this paper is to consider the application of bin picking and benchmark a set of motion planning algorithms to identify which are most suited in the given context.,The paper presents a selection of motion planning algorithms and defines benchmarks based on three different bin-picking scenarios. The evaluation is done based on a fixed set of tasks, which are planned and executed on a real and a simulated robot.,The benchmarking shows a clear difference between the planners and generally indicates that algorithms integrating optimization, despite longer planning time, perform better due to a faster execution.,The originality of this work lies in the selected set of planners and the specific choice of application. Most new planners are only compared to existing methods for specific applications chosen to demonstrate the advantages. However, with the specifics of another application, such as bin picking, it is not obvious which planner to choose.

Study on dual peg-in-hole insertion using of constraints formed in the environment

Abstract: Purpose The purpose of this paper is to develop a dual peg-in-hole insertion strategy. Dual peg-in-hole insertion is the most common task in manufacturing. Most of the previous work develop the insertion strategy in a two- or three-dimensional space, in which they suppose the initial yaw angle is zero and only concern the roll and pitch angles. However, in some case, the yaw angle could not be ignored due to the pose uncertainty of the peg on the gripper. Therefore, there is a need to design the insertion strategy in a higher-dimensional configuration space. Design/methodology/approach In this paper, the authors handle the insertion problem by converting it into several sub-problems based on the attractive region formed by the constraints. The existence of the attractive region in the high-dimensional configuration space is first discussed. Then, the construction of the high-dimensional attractive region with its sub-attractive region in the low-dimensional space is proposed. Therefore, the robotic insertion strategy can be designed in the subspace to eliminate some uncertainties between the dual pegs and dual holes. Findings Dual peg-in-hole insertion is realized without using of force sensors. The proposed strategy is also used to demonstrate the precision dual peg-in-hole insertion, where the clearance between the dual-peg and dual-hole is about 0.02 mm. Practical implications The sensor-less insertion strategy will not increase the cost of the assembly system and also can be used in the dual peg-in-hole insertion. Originality/value The theoretical and experimental analyses for dual peg-in-hole insertion are proposed without using of force sensor.

An experimental study on feature-based SLAM for multi-legged robots with RGB-D sensors

Abstract: Purpose This paper aims to evaluate four different simultaneous localization and mapping (SLAM) systems in the context of localization of multi-legged walking robots equipped with compact RGB-D sensors. This paper identifies problems related to in-motion data acquisition in a legged robot and evaluates the particular building blocks and concepts applied in contemporary SLAM systems against these problems. The SLAM systems are evaluated on two independent experimental set-ups, applying a well-established methodology and performance metrics. Design/methodology/approach Four feature-based SLAM architectures are evaluated with respect to their suitability for localization of multi-legged walking robots. The evaluation methodology is based on the computation of the absolute trajectory error (ATE) and relative pose error (RPE), which are performance metrics well-established in the robotics community. Four sequences of RGB-D frames acquired in two independent experiments using two different six-legged walking robots are used in the evaluation process. Findings The experiments revealed that the predominant problem characteristics of the legged robots as platforms for SLAM are the abrupt and unpredictable sensor motions, as well as oscillations and vibrations, which corrupt the images captured in-motion. The tested adaptive gait allowed the evaluated SLAM systems to reconstruct proper trajectories. The bundle adjustment-based SLAM systems produced best results, thanks to the use of a map, which enables to establish a large number of constraints for the estimated trajectory. Research limitations/implications The evaluation was performed using indoor mockups of terrain. Experiments in more natural and challenging environments are envisioned as part of future research. Practical implications The lack of accurate self-localization methods is considered as one of the most important limitations of walking robots. Thus, the evaluation of the state-of-the-art SLAM methods on legged platforms may be useful for all researchers working on walking robots’ autonomy and their use in various applications, such as search, security, agriculture and mining. Originality/value The main contribution lies in the integration of the state-of-the-art SLAM methods on walking robots and their thorough experimental evaluation using a well-established methodology. Moreover, a SLAM system designed especially for RGB-D sensors and real-world applications is presented in details.

Modular design of a teleoperated robotic control system for laparoscopic minimally invasive surgery based on ROS and RT-Middleware

Abstract: Purpose Robotic systems for laparoscopic minimally invasive surgery (MIS) always end up with highly sophisticated mechanisms and control schemes – making it a long and hard development process with a steep price. This paper aims to propose and realize a new, efficient and convenient strategy for building effective control systems for surgical and even other complex robotic systems. Design/methodology/approach A novel method that takes advantage of the modularization concept by integrating two middleware technologies (robot operating system and robotic technology middleware) into a common architecture based on the strengths of both was designed and developed. Findings Tests of the developed control system showed very low time-delay between the master and slave sides; good movement representation on the slave manipulator; and high positional and operational accuracy. Moreover, the new development strategy trial came with much higher efficiency and lower costs. Research limitations/implications This method results in a modularized and distributed control system that is amenable to collaboratively develop; convenient to modify and update; componentized and easy to extend; mutually independent among subsystems; and practicable to be running and communicating across multiple operating systems. However, experiments show that surgical training and updates of the robotic system are still required to achieve better proficiency for completing complex minimally invasive surgical operations with the proposed and developed system. Originality/value This research proposed and developed a novel modularization design method and a novel architecture for building a distributed teleoperation control system for laparoscopic MIS.

Robots that interact with humans: a review of safety technologies and standards

Abstract: This paper aims to provide details of the safety considerations, technologies and standards associated with robots that interact with, or operate in proximity to, humans.,Following an introduction, this paper first considers collaborative robots and discusses their safety features and the new technical specification ISO/TS 15066, together with certain allied safety standards. It then discusses ISO 13482 and a range of assistive, personal care and service robots which comply with this and highlights new standards that are under development. Mobile warehouse and delivery robots are then considered, together with the safety technologies used and the associated standards. Finally, brief concluding comments are drawn.,The recent proliferation of robots that interact with humans or operate in proximity to them has led to the development of standards and specifications which seek to ensure safe operation. These allow robot manufacturers to design inherently safe products that will gain market acceptance and also help to inspire confidence among users. A number of new standards and specifications have been proposed or are being developed, and this trend is set to continue as new classes of robotic products emerge.,All manner of robots are being developed which interact with humans, and this provides details of the associated safety considerations, technologies and standards.

Improved parameter optimization method for complex assembly process in robotic manufacturing

Abstract: Purpose High precision assembly processes using industrial robots require the process parameters to be tuned to achieve desired performance such as cycle time and first time through rate. Some researchers proposed methods such as design-of-experiments (DOE) to obtain optimal parameters. However, these methods only discuss how to find the optimal parameters if the part and/or workpiece location errors are in a certain range. In real assembly processes, the part and/or workpiece location errors could be different from batch to batch. Therefore, the existing methods have some limitations. This paper aims to improve the process parameter optimization method for complex robotic assembly process. Design/methodology/approach In this paper, the parameter optimization process based on DOE with different part and/or workpiece location errors is investigated. An online parameter optimization method is also proposed. Findings Experimental results demonstrate that the optimal parameters for different initial conditions are different and larger initial part and/or workpiece location errors will cause longer cycle time. Therefore, to improve the assembly process performance, the initial part and/or workpiece location errors should be compensated first, and the optimal parameters in production should be changed once the initial tool position is compensated. Experimental results show that the proposed method is very promising in reducing the cycle time in assembly processes. Research limitations/implications The proposed method is practical without any limitation. Practical implications The proposed technique is implemented and tested using a real industrial application, a valve body assembly process. Hence, the developed method can be directly implemented in production. Originality/value This paper provides a technique to improve the assembly efficiency by compensating the initial part location errors. An online parameter optimization method is also proposed to automatically perform the parameter optimization process without human intervention. Compared with the results using other methods, the proposed technology can greatly reduce the assembly cycle time.

Output feedback assistive control of single-DOF SEA powered exoskeletons

Abstract: Purpose This paper aims to overcome some of the practical difficulties in assistive control of exoskeletons by developing a new assistive algorithm, called output feedback assistive control (OFAC) method. This method does not require feedbacks from force, electromyography (EMG) or acceleration signals or even their estimated values. Design/methodology/approach The presented controller uses feedbacks from position and velocity of the output link of series elastic actuators (SEAs) to increase the apparent integral admittance of the assisted systems. Optimal controller coefficients are obtained by maximizing the assistance ratio subjected to constraints of stability, coupled stability and a newly defined comfort measure. Findings The results confirm the effectiveness of using the inherent properties of SEAs for removing the need for extra controversial sensors in assistive control of 1 degree of freedom (1-DOF) SEA powered exoskeletons. The results also clearly indicate the successful performance of the OFAC method in reducing the external forces required for moving the assisted systems. Practical implications As the provided experiments indicate, the proposed method can be easily applied to single DOF compliantly actuated exoskeletons to provide a more reliable assistance with lower costs. This is achieved by removing the need for extra controversial sensors. Originality/value This paper proposes a novel assistive controller for SEA-powered exoskeletons with a simple model-free structure and independent of any information about interaction forces and future paths of the system. It also removes the requirement for the extra sensors and transforms the assistive control of the compliantly actuated systems into a simpler problem of position control of the SEA motor.

Peg-In-Hole search using convex optimization techniques

Abstract: This paper aims to provide a solution to the first phase of a force-controlled circular Peg-In-Hole assembly using an industrial robot. The paper suggests motion planning of the robot’s end-effector so as to perform Peg-In-Hole search with minimum a priori information of the working environment.,The paper models Peg-In-Hole search problem as a problem of finding the minima in depth profile for a particular assembly. Thereafter, various optimization techniques are used to guide the robot to locate minima and complete the hole search. This approach is inspired by a human’s approach of searching a hole by moving peg in various directions so as to search a point of maximum insertion which is same as the minima in depth profile.,The usage of optimization techniques for hole search allows the robot to work with minimum a priori information of the working environment. Also, the iterative nature of the techniques adapts to any disturbance during assembly.,The techniques discussed here are quite useful if a force-controlled assembly needs to be performed in a highly unknown environment and also when the assembly setup can get disturbed in between.,The concept is original and provides a non-conventional use of optimization techniques, not for optimization of some process directly but for an industrial robot’s motion planning.

Design and experiment of a modular multisensory hand for prosthetic applications

Abstract: Purpose This paper aims to present the design and experiment of a modular multisensory prosthetic hand for applications. Design and experiment of a modular multisensory hand for prosthetic applications. Design/methodology/approach This paper reveals more details focusing on the appearance, mechanism design, electrical design and control of the prosthetic hand considering anthropomorphism, dexterity, sensing and controllability. The finger is internally integrated with the actuator, the transmission mechanism, the sensors and the controller as a modular unit. Integrated with multiple sensors, the prosthetic hand can not only perceive the position, the contact force and the temperature of the environment like a human hand but also provide the foundation for the practical control. Findings The experiments show that the prosthetic hand can accurately control the contact force to achieve stable grasps based on the sensors feedback and a simple and effective force-tracking impedance control algorithm. In addition, the experiments based on the cosmesis validate not only the cosmesis functionality but also the control performance for a prosthesis–cosmesis system. Practical implications Because of the small size, low weight, high integration, modularity and controllability, the prosthetic hand is easily applied to upper-limb amputees. Meanwhile, the finger as a modular unit is easy to be fixed, maintained and applied to a partial upper-limb amputee. Originality/value Each modular finger of the prosthetic hand integrated with the actuator, the transmission mechanism, the sensors and the controller as a whole can independently control the position and the force. The cosmetic glove design can provide pretty appearance without compromising the control performance.

Seam tracking investigation via striped line laser sensor

Abstract: Purpose This paper aims to propose a set of six-axis robot arm welding seam tracking experiment platform based on Halcon machine vision library to resolve the curve seam tracking issue. Design/methodology/approach Robot-based and image coordinate systems are converted based on the mathematical model of the three-dimensional measurement of structured light vision and conversion relations between robot-based and camera coordinate systems. An object tracking algorithm via weighted local cosine similarity is adopted to detect the seam feature points to prevent effectively the interference from arc and spatter. This algorithm models the target state variable and corresponding observation vector within the Bayes framework and finds the optimal region with highest similarity to the image-selected modules using cosine similarity. Findings The paper tests the approach and the experimental results show that using metal inert-gas (MIG) welding with maximum welding current of 200A can achieve real-time accurate curve seam tracking under strong arc light and splash. Minimal distance between laser stripe and welding molten pool can reach 15 mm, and sensor sampling frequency can reach 50 Hz. Originality/value Designing a set of six-axis robot arm welding seam tracking experiment platform with a system of structured light sensor based on Halcon machine vision library; and adding an object tracking algorithm to seam tracking system to detect image feature points. By this technology, this system can track the curve seam while welding.

Optimization design of drive system for industrial robots based on dynamic performance

Abstract: Purpose The global performance of industrial robots partly depends on the properties of drive system consisting of motor inertia, gearbox inertia, etc. This paper aims to deal with the problem of optimization of global dynamic performance for robotic drive system selected from available components. Design/methodology/approach Considering the performance specifications of drive system, an optimization model whose objective function is composed of working efficiency and natural frequency of robots is proposed. Meanwhile, constraints including the rated and peak torque of motor, lifetime of gearbox and light-weight were taken into account. Furthermore, the mapping relationship between discrete optimal design variables and component properties of drive system were presented. The optimization problem with mixed integer variables was solved by a mixed integer-laplace crossover power mutation algorithm. Findings The optimization results show that our optimization model and methods are applicable, and the performances are also greatly promoted without sacrificing any constraints of drive system. Besides, the model fits the overall performance well with respect to light-weight ratio, safety, cost reduction and others. Practical implications The proposed drive system optimization method has been used for a 4-DOF palletizing robot, which has been largely manufactured in a factory. Originality/value This paper focuses on how the simulation-based optimization can be used for the purpose of generating trade-offs between cost, performance and lifetime when designing robotic drive system. An applicable optimization model and method are proposed to handle the dynamic performance optimization problem of a drive system for industrial robot.

Development of an environment characterization methodology for optimal design of an agricultural robot

Abstract: Purpose The purpose of this paper is to describe a methodology for characterization of the robot environment to help solve such problem as designing an optimal agricultural robot for a specific agricultural task. Design/methodology/approach Defining and characterizing a task is a crucial step in the optimization of a task-specific robot. It is especially difficult in the agricultural domain because of the complexity and unstructured nature of the environment. In this research, trees are modeled from orchards and are used as the robot working environment, the geometrical features of an agricultural task are investigated and a method for designing an optimal agricultural robot is developed. Using this method, a simplified characteristic environment, representing the actual environment, is developed and used. Findings Case studies showing that the optimal robot, which is designed based on the characteristic environment, is similar to the optimal robot, which is designed based on the actual environment (less than 4 per cent error), is presented, while the optimization run time is significantly shorter (up to 22 times) when using the characteristic environment. Originality/value This paper proposes a new concept for solving the robot task-based optimization by the analysis of the task environment and characterizing it by a simpler artificial task environment. The methodology decreases the time of the optimal robot design, allowing to take into account more details in an acceptable time.

Real-time control of bilateral teleoperation system with adaptive computed torque method

Abstract: This paper aims to use the adaptive computed torque control (ACTC) method to eliminate the kinematic and dynamic uncertainties of master and slave robots and for the control of the system in the presence of forces originating from human and environment interaction.,In case of uncertainties in the robot parameters that are utilized in teleoperation studies and when the environment where interactions take place is not known and when there is a time delay, very serious problems take place in system performance. An adaptation rule was created to update uncertain parameters. In addition to this, disturbance observer was designed for slave robot. Lyapunov function was used to analyze the system’s position tracking and stability. A visual interface was designed to ensure that the movements of the master robot provided a visual feedback to the user.,In this study, a visual interface was created, and position and velocity control was achieved utilizing teleoperation; the system’s position tracking and stability were analyzed using the Lyapunov method; a simulation was applied in a real-time environment, and the performance results were analyzed.,This study consisted of both simulation and real-time studies. The teleoperation system, which was created in a laboratory environment, consisted of six-degree-of-freedom (DOF) master robots, six-DOF industrial robots and six-DOF virtual robots.

Online 3D LIDAR Monte Carlo localization with GPU acceleration

Abstract: This paper aims to focus on real-world mobile systems, and thus propose relevant contribution to the special issue on “Real-world mobile robot systems”. This work on 3D laser semantic mobile mapping and particle filter localization dedicated for robot patrolling urban sites is elaborated with a focus on parallel computing application for semantic mapping and particle filter localization. The real robotic application of patrolling urban sites is the goal; thus, it has been shown that crucial robotic components have reach high Technology Readiness Level (TRL).,Three different robotic platforms equipped with different 3D laser measurement system were compared. Each system provides different data according to the measured distance, density of points and noise; thus, the influence of data into final semantic maps has been compared. The realistic problem is to use these semantic maps for robot localization; thus, the influence of different maps into particle filter localization has been elaborated. A new approach has been proposed for particle filter localization based on 3D semantic information, and thus, the behavior of particle filter in different realistic conditions has been elaborated. The process of using proposed robotic components for patrolling urban site, such as the robot checking geometrical changes of the environment, has been detailed.,The focus on real-world mobile systems requires different points of view for scientific work. This study is focused on robust and reliable solutions that could be integrated with real applications. Thus, new parallel computing approach for semantic mapping and particle filter localization has been proposed. Based on the literature, semantic 3D particle filter localization has not yet been elaborated; thus, innovative solutions for solving this issue have been proposed. Recently, a semantic mapping framework that was already published was developed. For this reason, this study claimed that the authors’ applied studies during real-world trials with such mapping system are added value relevant for this special issue.,The main problem is the compromise between computer power and energy consumed by heavy calculations, thus our main focus is to use modern GPGPU, NVIDIA PASCAL parallel processor architecture. Recent advances in GPGPUs shows great potency for mobile robotic applications, thus this study is focused on increasing mapping and localization capabilities by improving the algorithms. Current limitation is related with the number of particles processed by a single processor, and thus achieved performance of 500 particles in real-time is the current limitation. The implication is that multi-GPU architectures for increasing the number of processed particle can be used. Thus, further studies are required.,The research focus is related to real-world mobile systems; thus, practical aspects of the work are crucial. The main practical application is semantic mapping that could be used for many robotic applications. The authors claim that their particle filter localization is ready to integrate with real robotic platforms using modern 3D laser measurement system. For this reason, the authors claim that their system can improve existing autonomous robotic platforms. The proposed components can be used for detection of geometrical changes in the scene; thus, many practical functionalities can be applied such as: detection of cars, detection of opened/closed gate, etc. […] These functionalities are crucial elements of the safe and security domain.,Improvement of safe and security domain is a crucial aspect of modern society. Protecting critical infrastructure plays an important role, thus introducing autonomous mobile platforms capable of supporting human operators of safe and security systems could have a positive impact if viewed from many points of view.,This study elaborates the novel approach of particle filter localization based on 3D data and semantic mapping. This original work could have a great impact on the mobile robotics domain, and thus, this study claims that many algorithmic and implementation issues were solved assuming real-task experiments. The originality of this work is influenced by the use of modern advanced robotic systems being a relevant set of technologies for proper evaluation of the proposed approach. Such a combination of experimental hardware and original algorithms and implementation is definitely an added value.

Kinematic calibration of a 3-DOF parallel tool head

Abstract: Purpose The purpose of this study is to develop a modified parameter identification method and a novel measurement method to calibrate a 3 degrees-of-freedom (3-DOF) parallel tool head. This parallel tool head is a parallel mechanism module in a five-axes hybrid machine tool. The proposed parameter identification method is named as the Modified Singular Value Decomposition (MSVD) method. It aims to overcome the difficulty of choosing the algorithm parameter in the regularization identification method. The novel measurement method is named as the vector projection (VP) method which is developed to expand the measurement range of self-made measurement implements. Design/methodology/approach Newton Iterative Algorithm based on Least Square Method is analyzed by using the Singular Value Decomposition method. Based on the analysis result, the MSVD method is proposed. The VP method transforms the angle measurement into the displacement measurement by taking full advantage of the ability that the 3-DOF parallel tool head can move in the X – Y plane. Findings The kinematic calibration approach is verified by calibration simulations, a Rotation Tool Center Point accuracy test and an experiment of machining an “S”-shaped test specimen. Originality/value The kinematic calibration approach with the MSVD method and VP method could be successfully applied to the 3-DOF parallel tool head and other 3-DOF parallel mechanisms.

Development and implementation of a robotic inspection system for power substations

Abstract: Purpose With the dramatically increasing number of substations, robots are expected to inspect equipment in the power industry. However, a traditional robotic system cannot work stably because of the strong electromagnetic field in substation. The purpose of this paper is to present a robust and stable robotic system for inspecting the substation equipment without the involvement of workers. Design/methodology/approach The paper presents in detail a robotic system that consists of a monitor center and a robot. With the monitor center, the workers could send inspection tasks and monitor status of the robot timely. Once a fault is detected, the alarm message will flash immediately to remind the workers. The patrol mode of the robot comprises teleoperation, regular inspection, special inspection and a key return mode. The robot only relies on a low-cost magnetic sensor for lateral positioning and radio frequency identification technology for longitudinal positioning when working under patrol mode. At each stop point, the substation equipment can be recognized quickly through accurate matching with the template image stored in the database. Findings It is shown that the robot could work efficiently and reliably in power substations. The positioning error is proved to be within 5 mm, compared to that of 20 cm by implementing integrated global positioning system-dead reckoning navigation. Because of the high positioning accuracy, it is much easier to recognize the substation equipment. It is observed that nearly 99 per cent of equipments can be recognized. Research limitations/implications The proposed robotic system is tested in a simple substation environment. While the proposed system shows satisfactory positioning results, further studies considering changeable weather condition will focus on improving the equipment recognition rate in such environment, such as rainy, snowy and strong sunlight. Practical implications The key contribution of this paper is that it provides a robotic system to inspect substation equipment instead of workers, to improve working efficiency and to reduce manpower cost. Originality/value This paper presents a robotic system to inspect substation equipment instead of workers. Four patrol modes are designed to meet the inspection demand. Comparing with the previous robotic systems, this system contributes to higher position accuracy and higher equipment recognition rate.

Adaptive neural network visual servoing of dual-arm robot for cyclic motion

Abstract: Purpose The purpose of this paper is to develop a vision-based dual-arm cyclic motion method, focusing on solving the problems of an uncertain grasp position of the object and the dual-arm joint-angle-drift phenomenon. Design/methodology/approach A novel cascade control structure is proposed which associates an adaptive neural network with kinematics redundancy optimization. A radial basis function (RBF) neural network in conjunction with a conventional proportional–integral (PI) controller is applied to compensate for the uncertainty of the image Jacobian matrix which includes the estimated grasp position. To avoid the joint-angle-drift phenomenon, a dual neural network (DNN) solver in conjunction with a PI controller and dual-arm-coordinated constraints is applied to optimize the closed-chain kinematics redundancy. Findings The proposed method was implemented on an industrial robotic MOTOMAN with two 7-degrees of freedom robotic arms. Two experiments of carrying a tray repeatedly and turning a steering wheel were carried out, and the results indicate that the closed-trajectories tracking is achieved successfully both in the image plane and the joint spaces with the uncertain grasp position, which validates the accuracy and realizability of the proposed PI-RBF-DNN control strategy. Originality/value The adaptive neural network visual servoing method is applied to the dual-arm cyclic motion with the uncertain grasp position of the object. The proposed method enhances the environmental adaptability of a dual-arm robot in a practical manipulation task.