Electronics

Research

Jump to: Review

18 pages, 1406 KiB

Open AccessFeature PaperArticle

Optimal Robot Motion Planning of Redundant Robots in Machining and Additive Manufacturing Applications

by Manuel Beschi, Stefano Mutti, Giorgio Nicola, Marco Faroni, Paolo Magnoni, Enrico Villagrossi and Nicola Pedrocchi

Electronics 2019, 8(12), 1437; https://doi.org/10.3390/electronics8121437 - 1 Dec 2019

Cited by 21 | Viewed by 4023

Abstract

The paper deals with the generation of optimal trajectories for industrial robots in machining and additive manufacturing applications. The proposed method uses an Ant Colony algorithm to solve a kinodynamic motion planning problem. It exploits the kinematic redundancy that is often present in [...] Read more.

The paper deals with the generation of optimal trajectories for industrial robots in machining and additive manufacturing applications. The proposed method uses an Ant Colony algorithm to solve a kinodynamic motion planning problem. It exploits the kinematic redundancy that is often present in these applications to optimize the execution of trajectory. At the same time, the robot kinematics and dynamics constraints are respected and robot collisions are avoided. To reduce the computational burden, the task workspace is discretized enabling the use of efficient network solver based on Ant Colony theory. The proposed method is validated in robotic milling and additive manufacturing real-world scenarios. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

21 pages, 788 KiB

Open AccessArticle

Motion Planning of a Second-Order Nonholonomic Chained Form System Based on Holonomy Extraction

by Masahide Ito

Electronics 2019, 8(11), 1337; https://doi.org/10.3390/electronics8111337 - 12 Nov 2019

Cited by 2 | Viewed by 2892

Abstract

This paper proposes a motion planning algorithm for dynamic nonholonomic systems represented in a second-order chained form. The proposed approach focuses on the so-called holonomy resulting from a kind of motion that traverses a closed path in a reduced configuration space of the [...] Read more.

This paper proposes a motion planning algorithm for dynamic nonholonomic systems represented in a second-order chained form. The proposed approach focuses on the so-called holonomy resulting from a kind of motion that traverses a closed path in a reduced configuration space of the system. According to the author’s literature survey, control approaches that make explicit use of holonomy exist for kinematic nonholonomic systems but does not exist for dynamic nonholonomic systems. However, the second-order chained form system is controllable. Also, the structure of the second-order chained form system analogizes with the one of the first-order chained form for kinematic nonholonomic systems. These survey and perspectives brought a hypothesis that there exists a specific control strategy for extracting holonomy of the second-order chained form system to the author. To verify this hypothesis, this paper shows that the holonomy of the second-order chained form system can be extracted by combining two appropriate pairs of sinusoidal inputs. Then, based on such holonomy extraction, a motion planning algorithm is constructed. Furthermore, the effectiveness is demonstrated through some simulations including an application to an underactuated manipulator. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

26 pages, 12193 KiB

Open AccessFeature PaperArticle

Energy-Saver Mobile Manipulator Based on Numerical Methods

by Julio Francisco Acosta Núñez, Víctor Hugo Andaluz Ortiz, Guillermo González-de-Rivera Peces and Javier Garrido Salas

Electronics 2019, 8(10), 1100; https://doi.org/10.3390/electronics8101100 - 29 Sep 2019

Cited by 8 | Viewed by 4657

Abstract

The work presents the kinematic and dynamic control of a mobile robotic manipulator system based on numerical methods. The proposal also presents the curvature analysis of a path not parameterized in time, for the optimization of energy consumption. The energy optimization considers two [...] Read more.

The work presents the kinematic and dynamic control of a mobile robotic manipulator system based on numerical methods. The proposal also presents the curvature analysis of a path not parameterized in time, for the optimization of energy consumption. The energy optimization considers two aspects: the velocity of execution in curves and the amount of movements generated by the robotic system. When a curve occurs on the predefined path, the execution velocity is analyzed throughout the system in a unified method to prevent skid effects from affecting the mobile manipulator, while the number of movements is limited by the redundancy presented by the robotic system to optimize energy use. The experimental results are shown to validate the mechanical and electronic construction of the system, the proposed controllers, and the saving of energy consumption. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

15 pages, 2864 KiB

Open AccessArticle

Design and Analysis of a Drive System for a Series Manipulator Based on Orthogonal-Fuzzy PID Control

by Haibo Zhou, Rui Chen, Shun Zhou and Zhenzhong Liu

Electronics 2019, 8(9), 1051; https://doi.org/10.3390/electronics8091051 - 18 Sep 2019

Cited by 32 | Viewed by 4848

Abstract

Because the proportional–integral–derivative (PID) parameters selected by experience are random, the control effect of fuzzy PID cannot be optimized. In order to improve the accuracy and stability of robot motion control, an orthogonal-fuzzy PID intelligent control method is proposed. In this paper, the [...] Read more.

Because the proportional–integral–derivative (PID) parameters selected by experience are random, the control effect of fuzzy PID cannot be optimized. In order to improve the accuracy and stability of robot motion control, an orthogonal-fuzzy PID intelligent control method is proposed. In this paper, the electric steering gear is used as the actuator, and the mathematical model of the servo motor joint drive system is established. The simulation analysis of the original control, PID control, fuzzy PID control, and orthogonal-fuzzy PID control of the manipulator joints in the Simulink software simulation environment and the motion control experiment of the manipulator show that using the orthogonal test method to adjust the PID parameters can quickly determine the appropriate PID parameters and greatly reduce the number of trials. The rise time, adjustment time, and overshoot of the system are significantly reduced by using fuzzy PID control, which can improve the adaptability of the system. By comparing and analyzing fuzzy PID and orthogonal-fuzzy PID control methods, it can be found that the system of orthogonal-fuzzy PID for optimal factor level combination (K_p = 0.1, K_i = 30 and K_d = 0.02) is the optimal system. The experiment results show that the orthogonal-fuzzy PID can further improve the accuracy of the system and reduce the oscillation process of the system near the steady state and make the motion more stable. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

24 pages, 7332 KiB

Open AccessArticle

Dynamic Motion Planning for Autonomous Assistive Surgical Robots

by Alessio Sozzi, Marcello Bonfè, Saverio Farsoni, Giacomo De Rossi and Riccardo Muradore

Electronics 2019, 8(9), 957; https://doi.org/10.3390/electronics8090957 - 29 Aug 2019

Cited by 19 | Viewed by 4510

Abstract

The paper addresses the problem of the generation of collision-free trajectories for a robotic manipulator, operating in a scenario in which obstacles may be moving at non-negligible velocities. In particular, the paper aims to present a trajectory generation solution that is fully executable [...] Read more.

The paper addresses the problem of the generation of collision-free trajectories for a robotic manipulator, operating in a scenario in which obstacles may be moving at non-negligible velocities. In particular, the paper aims to present a trajectory generation solution that is fully executable in real-time and that can reactively adapt to both dynamic changes of the environment and fast reconfiguration of the robotic task. The proposed motion planner extends the method based on a dynamical system to cope with the peculiar kinematics of surgical robots for laparoscopic operations, the mechanical constraint being enforced by the fixed point of insertion into the abdomen of the patient the most challenging aspect. The paper includes a validation of the trajectory generator in both simulated and experimental scenarios. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

21 pages, 3424 KiB

Open AccessArticle

Choosing the Best Locomotion Mode in Reconfigurable Rovers

by Carlos Jesús Pérez del Pulgar Mancebo, Pablo Romeo Manrique, Gonzalo Jesús Paz Delgado, José Ricardo Sánchez Ibáñez and Martin Azkarate

Electronics 2019, 8(7), 818; https://doi.org/10.3390/electronics8070818 - 22 Jul 2019

Cited by 3 | Viewed by 5526

Abstract

The use of autonomous rovers for planetary exploration is crucial to traverse long distances and perform new discoveries on other planets. One of the most important issues is related to the interaction between the rover wheel and terrain, which would help to save [...] Read more.

The use of autonomous rovers for planetary exploration is crucial to traverse long distances and perform new discoveries on other planets. One of the most important issues is related to the interaction between the rover wheel and terrain, which would help to save energy and even avoid getting entrapped. The use of reconfigurable rovers with different locomotion modes has demonstrated improvement of traction and energy consumption. Therefore, the objective of this paper is to determine the best locomotion mode during the rover traverse, based on simple parameters, which would be obtained from propioceptive sensors. For this purpose, interaction of different terrains have been modelled and analysed with the ExoTeR, a scale prototype rover of the European ExoMars 2020 mission. This rover is able to perform, among others, the wheel walking locomotion mode, which has been demonstrated to improve traction in different situations. Currently, it is difficult to decide the instant time the rover has to switch from this locomotion mode to another. This paper also proposes a novel method to estimate the slip ratio, useful for deciding the best locomotion mode. Finally, results are obtained from an immersive simulation environment. It shows how each locomotion mode is suitable for different terrains and slopes and the proposed method is able to estimate the slip ratio. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

15 pages, 2339 KiB

Open AccessArticle

Embedded Flight Control Based on Adaptive Sliding Mode Strategy for a Quadrotor Micro Air Vehicle

by Herman Castañeda and J.L. Gordillo

Electronics 2019, 8(7), 793; https://doi.org/10.3390/electronics8070793 - 16 Jul 2019

Cited by 16 | Viewed by 4175

Abstract

The design of an embedded flight controller for a quadrotor micro air vehicle, which is subject to uncertainties and perturbations, is addressed. In order to obtain robustness against bounded uncertainties and disturbances, an adaptive sliding mode controller is proposed. The control adaptive gains [...] Read more.

The design of an embedded flight controller for a quadrotor micro air vehicle, which is subject to uncertainties and perturbations, is addressed. In order to obtain robustness against bounded uncertainties and disturbances, an adaptive sliding mode controller is proposed. The control adaptive gains allow using only necessary control to satisfy the task, reducing the chattering effect and at the same time reject external perturbations. Furthermore, a stability analysis of the closed-loop system is given. Finally, simulations and experimental results carried out on a commercial micro air vehicle demonstrate the feasibility and advantages of the proposed flight controller. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

23 pages, 10327 KiB

Open AccessArticle

Q-Learning of Straightforward Gait Pattern for Humanoid Robot Based on Automatic Training Platform

by Ching-Chang Wong, Chih-Cheng Liu, Sheng-Ru Xiao, Hao-Yu Yang and Meng-Cheng Lau

Electronics 2019, 8(6), 615; https://doi.org/10.3390/electronics8060615 - 31 May 2019

Cited by 7 | Viewed by 5135

Abstract

In this paper, an oscillator-based gait pattern with sinusoidal functions is designed and implemented on a field-programmable gate array (FPGA) chip to generate a trajectory plan and achieve bipedal locomotion for a small-sized humanoid robot. In order to let the robot can walk [...] Read more.

In this paper, an oscillator-based gait pattern with sinusoidal functions is designed and implemented on a field-programmable gate array (FPGA) chip to generate a trajectory plan and achieve bipedal locomotion for a small-sized humanoid robot. In order to let the robot can walk straight, the turning direction is viewed as a parameter of the gait pattern and Q-learning is used to obtain a straightforward gait pattern. Moreover, an automatic training platform is designed so that the learning process is automated. In this way, the turning direction can be adjusted flexibly and efficiently under the supervision of the automatic training platform. The experimental results show that the proposed learning framework allows the humanoid robot to gradually walk straight in the automated learning process. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

19 pages, 7619 KiB

Open AccessArticle

Active Disturbance Rejection Control of Multi-Joint Industrial Robots Based on Dynamic Feedforward

by Xin Cheng, Xiao Tu, Yunfei Zhou and Rougang Zhou

Electronics 2019, 8(5), 591; https://doi.org/10.3390/electronics8050591 - 27 May 2019

Cited by 17 | Viewed by 3903

Abstract

In this paper, the dynamics-based high-performance robot motion control technology has been mainly studied, and the overall structure is controlled via dynamics forward, given the nonlinearity, strong coupling and time-variability of robots. Considering the unavailability of precise robot model parameters and the uncertain [...] Read more.

In this paper, the dynamics-based high-performance robot motion control technology has been mainly studied, and the overall structure is controlled via dynamics forward, given the nonlinearity, strong coupling and time-variability of robots. Considering the unavailability of precise robot model parameters and the uncertain disturbance in real operation, we put forward an active disturbance rejection control (ADRC) strategy based on dynamic feedforward, aiming to improve the control robustness and combining the simple structure, strong anti- disturbance ability, and no restriction from the control model of ADRC. Given the multi-joint coupling of robots, controlled decoupling is conducted by using dynamic characteristics. The ADRC cascade control structure and algorithm based on dynamic feedforward have been studied and the closed-loop stability of the system is investigated by analyzing the system dynamic linearization compensation and the anti-disturbance ability of the extended state observer. Experiments have shown the new strategy is more robust over uncertain disturbance than the conventional proportional-integral-derivative control strategy. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

21 pages, 3503 KiB

Open AccessArticle

A Hierarchical Cooperative Mission Planning Mechanism for Multiple Unmanned Aerial Vehicles

by Zhe Zhao, Jian Yang, Yifeng Niu, Yu Zhang and Lincheng Shen

Electronics 2019, 8(4), 443; https://doi.org/10.3390/electronics8040443 - 18 Apr 2019

Cited by 14 | Viewed by 3854

Abstract

In this paper, the cooperative multi-task online mission planning for multiple Unmanned Aerial Vehicles (UAVs) is studied. Firstly, the dynamics of unmanned aerial vehicles and the mission planning problem are studied. Secondly, a hierarchical mechanism is proposed to deal with the complex multi-UAV [...] Read more.

In this paper, the cooperative multi-task online mission planning for multiple Unmanned Aerial Vehicles (UAVs) is studied. Firstly, the dynamics of unmanned aerial vehicles and the mission planning problem are studied. Secondly, a hierarchical mechanism is proposed to deal with the complex multi-UAV multi-task mission planning problem. In the first stage, the flight paths of UAVs are generated by the Dubins curve and B-spline mixed method, which are defined as “CBC)” curves, where “C” stands for circular arc and “B” stands for B-spline segment. In the second stage, the task assignment problem is solved as multi-base multi-traveling salesman problem, in which the “CBC” flight paths are used to estimate the trajectory costs. In the third stage, the flight trajectories of UAVs are generated by using Gaussian pseudospectral method (GPM). Thirdly, to improve the computational efficiency, the continuous and differential initial trajectories are generated based on the “CBC” flight paths. Finally, numerical simulations are presented to demonstrate the proposed approach, the designed initial solution search algorithm is compared with existing methods. These results indicate that the proposed hierarchical mission planning method can produce satisfactory mission planning results efficiently. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

17 pages, 4044 KiB

Open AccessArticle

Advanced Backstepping Trajectory Control for Skid-Steered Duct-Cleaning Mobile Platforms

by Wootae Jeong, Seungwoo Jeon and Dahae Jeong

Electronics 2019, 8(4), 401; https://doi.org/10.3390/electronics8040401 - 4 Apr 2019

Cited by 4 | Viewed by 3506

Abstract

In recent years, a novel skid-steered duct-cleaning mobile platform was developed to remove dust accumulated on the inner surface of an air-ventilation duct with its rolling brushes. During the cleaning process, the irregular brushing pressure acting on the upper arm makes it difficult [...] Read more.

In recent years, a novel skid-steered duct-cleaning mobile platform was developed to remove dust accumulated on the inner surface of an air-ventilation duct with its rolling brushes. During the cleaning process, the irregular brushing pressure acting on the upper arm makes it difficult to control the platform through the duct path. In fact, the repulsive external force due to the brushing pressure is not directly measurable or computable because of the nonlinear deformation of the brush. In addition, dynamic uncertainties in platform motion can occur during reciprocating motion of the upper arm. Therefore, a model-based trajectory-tracking controller is required to control the mobile cleaning platform by considering irregular external forces. The robustness of the developed controller based on the adaptable PD(Proportional-Derivative)-backstepping method has been proposed and evaluated through numerical analysis and experiments. For the turning motion in a narrow space, a skid-steered platform model considering wheel slippage has been also implemented. The result shows that tracking control can be successfully achieved under various conditions of frequencies in brushing-arm motion and torque limitation of the traction motors. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

16 pages, 684 KiB

Open AccessFeature PaperArticle

A Passivity-Based Strategy for Manual Corrections in Human-Robot Coaching

by Chiara Talignani Landi, Federica Ferraguti, Cesare Fantuzzi and Cristian Secchi

Electronics 2019, 8(3), 320; https://doi.org/10.3390/electronics8030320 - 13 Mar 2019

Cited by 5 | Viewed by 3348

Abstract

In recent years, new programming techniques have been developed in the human-robot collaboration (HRC) field. For example, walk-through programming allows to program the robot in an easy and intuitive way. In this context, a modification of a portion of the trajectory usually requires [...] Read more.

In recent years, new programming techniques have been developed in the human-robot collaboration (HRC) field. For example, walk-through programming allows to program the robot in an easy and intuitive way. In this context, a modification of a portion of the trajectory usually requires the teaching of the path from the beginning. In this paper we propose a passivity-based method to locally change a trajectory based on a manual human correction. At the beginning the robot follows the nominal trajectory, encoded through the Dynamical Movement Primitives, by setting high control gains. When the human grasps the end-effector, the robot is made compliant and he/she can drive it along the correction. The correction is optimally joined to the nominal trajectory, resuming the path tracking. In order to avoid unstable behaviors, the variation of the control gains is performed exploiting energy tanks, preserving the passivity of the interaction. Finally, the correction is spatially fixed so that a variation in the boundary conditions (e.g., the initial/final points) does not affect the modification. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

19 pages, 2640 KiB

Open AccessArticle

Network-Oriented Real-Time Embedded System Considering Synchronous Joint Space Motion for an Omnidirectional Mobile Robot

by Raimarius Delgado and Byoung Wook Choi

Electronics 2019, 8(3), 317; https://doi.org/10.3390/electronics8030317 - 13 Mar 2019

Cited by 13 | Viewed by 4152

Abstract

This paper proposes a real-time embedded system for joint space control of omnidirectional mobile robots. Actuators driving an omnidirectional mobile robot are connected in a line topology which requires synchronization to move simultaneously in translation and rotation. We employ EtherCAT, a real-time Ethernet [...] Read more.

This paper proposes a real-time embedded system for joint space control of omnidirectional mobile robots. Actuators driving an omnidirectional mobile robot are connected in a line topology which requires synchronization to move simultaneously in translation and rotation. We employ EtherCAT, a real-time Ethernet network, to control servo controllers for the mobile robot. The first part of this study focuses on the design of a low-cost embedded system utilizing an open-source EtherCAT master. Although satisfying real-time constraints is critical, a desired trajectory on the center of the mobile robot should be decomposed into the joint space to drive the servo controllers. For the center of the robot, a convolution-based path planner and a corresponding joint space control algorithm are presented considering its physical limits. To avoid obstacles that introduce geometric constraints on the curved path, a trajectory generation algorithm considering high curvature turning points is adapted for an omnidirectional mobile robot. Tracking a high curvature path increases mathematical complexity, which requires precise synchronization between the actuators of the mobile robot. An improvement of the distributed clock—the synchronization mechanism of EtherCAT for slaves—is presented and applied to the joint controllers of the mobile robot. The local time of the EtherCAT master is dynamically adjusted according to the drift of the reference slave, which minimizes the synchronization error between each joint. Experiments are conducted on our own developed four-wheeled omnidirectional mobile robot. The experiment results confirm that the proposed system is very effective in real-time control applications for precise motion control of the robot even for tracking high curvature paths. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

27 pages, 4703 KiB

Open AccessArticle

Robot Motion Planning in an Unknown Environment with Danger Space

by Hadi Jahanshahi, Mohsen Jafarzadeh, Naeimeh Najafizadeh Sari, Viet-Thanh Pham, Van Van Huynh and Xuan Quynh Nguyen

Electronics 2019, 8(2), 201; https://doi.org/10.3390/electronics8020201 - 10 Feb 2019

Cited by 31 | Viewed by 6138

Abstract

This paper discusses the real-time optimal path planning of autonomous humanoid robots in unknown environments regarding the absence and presence of the danger space. The danger is defined as an environment which is not an obstacle nor free space and robot are permitted [...] Read more.

This paper discusses the real-time optimal path planning of autonomous humanoid robots in unknown environments regarding the absence and presence of the danger space. The danger is defined as an environment which is not an obstacle nor free space and robot are permitted to cross when no free space options are available. In other words, the danger can be defined as the potentially risky areas of the map. For example, mud pits in a wooded area and greasy floor in a factory can be considered as a danger. The synthetic potential field, linguistic method, and Markov decision processes are methods which have been reviewed for path planning in a free-danger unknown environment. The modified Markov decision processes based on the Takagi–Sugeno fuzzy inference system is implemented to reach the target in the presence and absence of the danger space. In the proposed method, the reward function has been calculated without the exact estimation of the distance and shape of the obstacles. Unlike other existing path planning algorithms, the proposed methods can work with noisy data. Additionally, the entire motion planning procedure is fully autonomous. This feature makes the robot able to work in a real situation. The discussed methods ensure the collision avoidance and convergence to the target in an optimal and safe path. An Aldebaran humanoid robot, NAO H25, has been selected to verify the presented methods. The proposed methods require only vision data which can be obtained by only one camera. The experimental results demonstrate the efficiency of the proposed methods. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

28 pages, 786 KiB

Open AccessFeature PaperArticle

A Smart Many-Core Implementation of a Motion Planning Framework along a Reference Path for Autonomous Cars

by Gianpiero Cabodi, Paolo Camurati, Alessandro Garbo, Michele Giorelli, Stefano Quer and Francesco Savarese

Electronics 2019, 8(2), 177; https://doi.org/10.3390/electronics8020177 - 2 Feb 2019

Cited by 11 | Viewed by 3683

Abstract

Research on autonomous cars, early intensified in the 1990s, is becoming one of the main research paths in automotive industry. Recent works use Rapidly-exploring Random Trees to explore the state space along a given reference path, and to compute the minimum time collision-free [...] Read more.

Research on autonomous cars, early intensified in the 1990s, is becoming one of the main research paths in automotive industry. Recent works use Rapidly-exploring Random Trees to explore the state space along a given reference path, and to compute the minimum time collision-free path in real time. Those methods do not require good approximations of the reference path, they are able to cope with discontinuous routes, they are capable of navigating in realistic traffic scenarios, and they derive their power from an extensive computational effort directed to improve the quality of the trajectory from step to step. In this paper, we focus on re-engineering an existing state-of-the-art sequential algorithm to obtain a CUDA-based GPGPU (General Purpose Graphics Processing Units) implementation. To do that, we show how to partition the original algorithm among several working threads running on the GPU, how to propagate information among threads, and how to synchronize those threads. We also give detailed evidence on how to organize memory transfers between the CPU and the GPU (and among different CUDA kernels) such that planning times are optimized and the available memory is not exceeded while storing massive amounts of fuse data. To sum up, in our application the GPU is used for all main operations, the entire application is developed in the CUDA language, and specific attention is paid to concurrency, synchronization, and data communication. We run experiments on several real scenarios, comparing the GPU implementation with the CPU one in terms of the quality of the generated paths and in terms of computation (wall-clock) times. The results of our experiments show that embedded GPUs can be used as an enabler for real-time applications of computationally expensive planning approaches. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

17 pages, 5690 KiB

Open AccessArticle

A Free Navigation of an AGV to a Non-Static Target with Obstacle Avoidance

by Daniel Teso-Fz-Betoño, Ekaitz Zulueta, Unai Fernandez-Gamiz, Iñigo Aramendia and Irantzu Uriarte

Electronics 2019, 8(2), 159; https://doi.org/10.3390/electronics8020159 - 1 Feb 2019

Cited by 17 | Viewed by 5029

Abstract

The industry is changing in order to improve the economy sector. This is the reason why technology is improving and developing new devices. The autonomous guided vehicle with free navigation is a new machine, which uses different techniques to move such as mapping, [...] Read more.

The industry is changing in order to improve the economy sector. This is the reason why technology is improving and developing new devices. The autonomous guided vehicle with free navigation is a new machine, which uses different techniques to move such as mapping, localization, path planning, and path following. In this paper, a path following is proposed. The path following is called moving to a point, which uses the proportional distance between the target and the autonomous guided vehicles (AGV) to calculate the velocity and direction. If some obstacles appear in the trajectory, however, the vehicle stops. Instead of stopping the machine, by using moving to a point logic, an obstacle avoidance function will be implemented. In this implementation, different parameters can be configured, such as: security distance, which determinates when the obstacle avoidance must correct the pose; and proportional values, which modify the velocity and steering commands. It is also compared to a dynamic window approach (DWA) obstacle avoidance solution. Additionally, the AGV navigates to a non-static target with a path following algorithm. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

17 pages, 7407 KiB

Open AccessArticle

Trapezoidal Motion Profile to Suppress Residual Vibration of Flexible Object Moved by Robot

by Hyun Joong Yoon, Seong Youb Chung, Han Sol Kang and Myun Joong Hwang

Electronics 2019, 8(1), 30; https://doi.org/10.3390/electronics8010030 - 1 Jan 2019

Cited by 31 | Viewed by 8093

Abstract

The residual vibration when a robot manipulator is operated at high speed needs to be suppressed. These vibrations are generated by the resonance of a flexible object being moved by the robot, and research on control algorithms and motion profiles is ongoing to [...] Read more.

The residual vibration when a robot manipulator is operated at high speed needs to be suppressed. These vibrations are generated by the resonance of a flexible object being moved by the robot, and research on control algorithms and motion profiles is ongoing to reduce them. In this paper, we propose a method to reduce the residual vibration of an object moved by a robot manipulator by optimizing the acceleration/deceleration time calculated using the object’s natural frequency. The relationship between acceleration/deceleration time and the residual vibration in a trapezoidal velocity profile is considered by analyzing the scenario when the jerking motion characteristic of such vibrations occurs. The results of experiments using a commercial robot show that residual vibrations can be reduced by the proposed method without the need for an additional feedback control algorithm while transferring a flexible object over small and large distances. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

18 pages, 11289 KiB

Open AccessArticle

Learning the Metric of Task Constraint Manifolds for Constrained Motion Planning

by Fusheng Zha, Yizhou Liu, Wei Guo, Pengfei Wang, Mantian Li, Xin Wang and Jingxuan Li

Electronics 2018, 7(12), 395; https://doi.org/10.3390/electronics7120395 - 5 Dec 2018

Cited by 6 | Viewed by 4057

Abstract

Finding feasible motion for robots with high-dimensional configuration space is a fundamental problem in robotics. Sampling-based motion planning algorithms have been shown to be effective for these high-dimensional systems. However, robots are often subject to task constraints (e.g., keeping a glass of water [...] Read more.

Finding feasible motion for robots with high-dimensional configuration space is a fundamental problem in robotics. Sampling-based motion planning algorithms have been shown to be effective for these high-dimensional systems. However, robots are often subject to task constraints (e.g., keeping a glass of water upright, opening doors and coordinating operation with dual manipulators), which introduce significant challenges to sampling-based motion planners. In this work, we introduce a method to establish approximate model for constraint manifolds, and to compute an approximate metric for constraint manifolds. The manifold metric is combined with motion planning methods based on projection operations, which greatly improves the efficiency and success rate of motion planning tasks under constraints. The proposed method Approximate Graph-based Constrained Bi-direction Rapidly Exploring Tree (AG-CBiRRT), which improves upon CBiRRT, and CBiRRT were tested on several task constraints, highlighting the benefits of our approach for constrained motion planning tasks. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

27 pages, 1297 KiB

Open AccessArticle

A Fast Global Flight Path Planning Algorithm Based on Space Circumscription and Sparse Visibility Graph for Unmanned Aerial Vehicle

by Abdul Majeed and Sungchang Lee

Electronics 2018, 7(12), 375; https://doi.org/10.3390/electronics7120375 - 2 Dec 2018

Cited by 39 | Viewed by 8542

Abstract

This paper proposes a new flight path planning algorithm that finds collision-free, optimal/near-optimal and flyable paths for unmanned aerial vehicles (UAVs) in three-dimensional (3D) environments with fixed obstacles. The proposed algorithm significantly reduces pathfinding computing time without significantly degrading path lengths by using [...] Read more.

This paper proposes a new flight path planning algorithm that finds collision-free, optimal/near-optimal and flyable paths for unmanned aerial vehicles (UAVs) in three-dimensional (3D) environments with fixed obstacles. The proposed algorithm significantly reduces pathfinding computing time without significantly degrading path lengths by using space circumscription and a sparse visibility graph in the pathfinding process. We devise a novel method by exploiting the information about obstacle geometry to circumscribe the search space in the form of a half cylinder from which a working path for UAV can be computed without sacrificing the guarantees on near-optimality and speed. Furthermore, we generate a sparse visibility graph from the circumscribed space and find the initial path, which is subsequently optimized. The proposed algorithm effectively resolves the efficiency and optimality trade-off by searching the path only from the high priority circumscribed space of a map. The simulation results obtained from various maps, and comparison with the existing methods show the effectiveness of the proposed algorithm and verify the aforementioned claims. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

21 pages, 3054 KiB

Open AccessArticle

Complete Path Planning for a Tetris-Inspired Self-Reconfigurable Robot by the Genetic Algorithm of the Traveling Salesman Problem

by Anh Vu Le, Manimuthu Arunmozhi, Prabakaran Veerajagadheswar, Ping-Cheng Ku, Tran Hoang Quang Minh, Vinu Sivanantham and Rajesh Elara Mohan

Electronics 2018, 7(12), 344; https://doi.org/10.3390/electronics7120344 - 22 Nov 2018

Cited by 40 | Viewed by 7045

Abstract

The efficiency of autonomous systems that tackle tasks such as home cleaning, agriculture harvesting, and mineral mining depends heavily on the adopted area coverage strategy. Extensive navigation strategies have been studied and developed, but few focus on scenarios with reconfigurable robot agents. This [...] Read more.

The efficiency of autonomous systems that tackle tasks such as home cleaning, agriculture harvesting, and mineral mining depends heavily on the adopted area coverage strategy. Extensive navigation strategies have been studied and developed, but few focus on scenarios with reconfigurable robot agents. This paper proposes a navigation strategy that accomplishes complete path planning for a Tetris-inspired hinge-based self-reconfigurable robot (hTetro), which consists of two main phases. In the first phase, polyomino form-based tilesets are generated to cover the predefined area based on the tiling theory, which generates a series of unsequenced waypoints that guarantee complete coverage of the entire workspace. Each waypoint specifies the position of the robot and the robot morphology on the map. In the second phase, an energy consumption evaluation model is constructed in order to determine a valid strategy to generate the sequence of the waypoints. The cost value between waypoints is formulated under the consideration of the hTetro robot platform’s kinematic design, where we calculate the minimum sum of displacement of the four blocks in the hTetro robot. With the cost function determined, the waypoint sequencing problem is then formulated as a travelling salesman problem (TSP). In this paper, a genetic algorithm (GA) is proposed as a strong candidate to solve the TSP. The GA produces a viable navigation sequence for the hTetro robot to follow and to accomplish complete coverage tasks. We performed an analysis across several complete coverage algorithms including zigzag, spiral, and greedy search to demonstrate that TSP with GA is a valid and considerably consistent waypoint sequencing strategy that can be implemented in real-world hTetro robot navigations. The scalability of the proposed framework allows the algorithm to produce reliable results while navigating within larger workspaces in the real world, and the flexibility of the framework ensures easy implementation of the algorithm on other polynomial-based shape shifting robots. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Graphical abstract

20 pages, 39719 KiB

Open AccessArticle

Path Planning for Mobile Agents Using a Genetic Algorithm with a Direction Guided Factor

by Hyeok-Yeon Lee, Hyunwoo Shin and Junjae Chae

Electronics 2018, 7(10), 212; https://doi.org/10.3390/electronics7100212 - 22 Sep 2018

Cited by 35 | Viewed by 7299

Abstract

This paper suggests a novel methodology in collision-free shortest path planning (CFSPP) problems for mobile agents (MAs) using a method that combines a genetic algorithm (GA) and a direction factor toward a target point. In the CFSPP problem, MAs find the shortest path [...] Read more.

This paper suggests a novel methodology in collision-free shortest path planning (CFSPP) problems for mobile agents (MAs) using a method that combines a genetic algorithm (GA) and a direction factor toward a target point. In the CFSPP problem, MAs find the shortest path from the starting point to the target point while avoiding certain obstacles. The paper proposes an obstacle-based search methodology that identifies critical collision-free points adjacent to given obstacles. When critical obstacles are found via CFSPP, this study suggests favorable paths in 2-dimensional space found using the obstacle-based GA (OBGA). The OBGA has four advantages. First, it effectively narrows the search spaces compared to free space-based methodologies. It also determines shorter collision-free paths, and it only requires a short amount of time. Finally, convergence occurs more quickly than in previous studies. The proposed method also works properly in larger and more complex environments, indicating that it can be applied to more practical problems. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Graphical abstract

Review

Jump to: Research

32 pages, 17375 KiB

Open AccessReview

Review and Comparison of Path Tracking Based on Model Predictive Control

by Guoxing Bai, Yu Meng, Li Liu, Weidong Luo, Qing Gu and Li Liu

Electronics 2019, 8(10), 1077; https://doi.org/10.3390/electronics8101077 - 23 Sep 2019

Cited by 64 | Viewed by 6609

Abstract

Recently, model predictive control (MPC) is increasingly applied to path tracking of mobile devices, such as mobile robots. The characteristics of these MPC-based controllers are not identical due to the different approaches taken during design. According to the differences in the prediction models, [...] Read more.

Recently, model predictive control (MPC) is increasingly applied to path tracking of mobile devices, such as mobile robots. The characteristics of these MPC-based controllers are not identical due to the different approaches taken during design. According to the differences in the prediction models, we believe that the existing MPC-based path tracking controllers can be divided into four categories. We named them linear model predictive control (LMPC), linear error model predictive control (LEMPC), nonlinear model predictive control (NMPC), and nonlinear error model predictive control (NEMPC). Subsequently, we built these four controllers for the same mobile robot and compared them. By comparison, we got some conclusions. The real-time performance of LMPC and LEMPC is good, but they are less robust to reference paths and positioning errors. NMPC performs well when the reference velocity is high and the radius of the reference path is small. It is also robust to positioning errors. However, the real-time performance of NMPC is slightly worse. NEMPC has many disadvantages. Like LMPC and LEMPC, it performs poorly when the reference velocity is high and the radius of the reference path is small. Its real-time performance is also not good enough. Full article

(This article belongs to the Special Issue Motion Planning and Control for Robotics)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Motion Planning and Control for Robotics

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (22 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI