Showing 6 results for Obstacle Avoidance
Volume 12, Issue 3 (12-2012)
Abstract
This paper presents a parameterization method to optimal trajectory planning and dynamic obstacle avoidance for Omni-directional robots. The aim of trajectory planning is minimizing a quadratic cost function while a maximum limitation on velocity and acceleration of robot is considered. First, we parameterize the trajectory using polynomial functions with unknown coefficients which transforms trajectory planning to an optimization problem. Then we use a novel method to solving the optimization problem and obtaining the unknown parameters. Finally, the efficiency of proposed approach is confirmed by simulation.
Hossein Rezaeifar, Farshid Najafi,
Volume 15, Issue 8 (10-2015)
Abstract
In order to utilize robots for industrial tasks, designing a suitable path is necessary.Executing the path by the robot in the presence of obstacles, makes the path planning task a difficult one. In addition, path planning is a time consuming task and needs expertise to define certain path for each industrial job. In this paper, uses Jerk-minimum method, B-Spline curves, via-point, and obstacle avoidance algorithm to automatically generate a suitable and safe path for a simulated 7 degrees of freedom industrial manipulator.A user determines via-points for robot trajectory using a Kinect sensor,then a combination of Jerk-minimum method, B-Spline curves, a path is generated. This path is checked by an obstacle avoidance algorithm,and a final path is generated. The obstacle avoidance algorithm uses the inverse kinematic equation of the robot to modify the robot trajectory. One of the advantages of the proposed method is both to facilitate trajectory planning for the user and to create a smooth trajectory for the robotic arm.
Mehdi Tale Masouleh, Hossein Kazemi, Pouria Nozari Porshokuhi, Roya Sabbagh Novin,
Volume 15, Issue 12 (2-2016)
Abstract
This paper deals with the collision-free path planning of planar parallel robot by avoiding mechanical interferences and obstacle within the workspace. For this purpose, an Artificial Potential Field approach is developed. As the main contribution of this paper, In order to circumvent the local minima problem of the potential fields, a novel approach is proposed which is a combination of Potential Field approach, Fuzzy Logic and also a novel algorithm consisting of Following Obstacle as well as Virtual Obstacle methods, as a hybrid method. Moreover, the inverse kinematic problem of the 3-RRR planar parallel robot is analyzed and then the aforementioned hybrid method is applied to this mechanism in singular-free case. It is worth mentioning that, in this paper, all the probable collisions, i.e., the collision between the mechanism and the obstacles and also among the links, are taken into accounts. Two general cases have been considered in collision-free path planning simulation; the first case considered a mobile robot in several workspaces and the second one was assigned to the 3-RRR planar parallel robot path planning. Results of the simulations, which are implemented in C programming language for the sake of real-time purposes. reveal that for the both cases, the newly proposed hybrid path planning method is efficient enough for the mobile robot, or the end-effector of the planar parallel robot to reach the goal without colliding with the obstacles.
Maryam Asgari, Mohammad Reza Jahed Motlagh, Khalil Alipour,
Volume 16, Issue 4 (6-2016)
Abstract
This paper investigates the leader-follower formation control problem of nonholonomic mobile robots based on backstepping technique composed with the bio-inspired neurodynamics while avoiding collision with obstacles. Kinematics model of robot and nonholonomic constraint are introduced and formation control scheme is formed based on backstepping technique. In order to solve velocity jump in backstepping kinematics model, the bio-inspired neurodynamic approach is used. In most of the previous studies, researches are used separation-bearing approach and also supposed that desired separation and bearing are constant. In this paper this assumption is relaxed and desired separation and bearing are considered to be time varying. Error dynamics equations are derived and a new controller is proposed. Also an auxiliary reference angular velocity control law is proposed to guarantee global asymptotic stability of the followers and local asymptotic stability of the entire formation according to direct method of Lyapunov. A common example of changing the formation is obstacle avoidance, when an obstacle is located within a follower path and is not in its leader path. Time varying functions for desired separation and bearing are chosen and the new controller is developed with its proof of stability. Simulations results reveal that each follower robot can track its real time leader employing the proposed kinematic controller while avoiding obstacles. Furthermore control inputs at the start moment and also while avoiding obstacles, do not contain impractical jumps and are reasonable thanks to integrating bio-inspired neurodynamic with backstepping technique.
Saeed Khodaei, Akbar Allahverdizadeh, Behnam Dadashzadeh,
Volume 17, Issue 6 (8-2017)
Abstract
This paper presents a new method based on machine vision for mobile robots to detect and avoid obstacles in unknown environments. One of the challenges of mobile robots trajectory control in unknown environments is that their obstacle avoidance system to be designed robust to material and shape of the obstacle. In this research a mobile robot equipped with a camera is designed and fabricated. Also an algorithm is proposed and implemented on the robot in order to detect obstacles by image processing and to control the robot trajectory. Three color laser pointers are mounted on the robot with certain angles that emit beams to the ground at ahead of the robot. The received images from camera contain these colored points that their coordinates are determined by image processing. Then position of any possible obstacle is detected using the proposed algorithm and the robot is commanded to avoid obstacles by changing its path. These obstacles can be static or dynamic. Our experimental results show that the proposed method, with a high reliability, has the ability to detect and avoid obstacles with any shape and material whereas other similar methods had restrictions in this regard.
A. Kosari, S.i. Kassaei , A. Rostampour , S. Seyedzamani,
Volume 20, Issue 5 (5-2020)
Abstract
In this paper, a novel method for designing the flight paths of an aircraft is presented based on the concept of conformal mapping. Here, a low-altitude route-planning problem has been considered. In this problem, maintaining the control effort to reduce aircraft's altitude and increasing the speed with the limitations of Terrain Following (TF) and Terrain Avoidance (TA) issues, is the main strategy of this performance maneuver. In the proposed approach, attempts are made to convert the real space including terrains and obstacles, in which their data are provided using a digital elevation map, into a pseudo obstacle-free virtual space with no barriers and altitude constraints. In this regard, the concept of conformal mapping has been used as a facilitating mathematical tool for this problem-solving space transformation. The transformation of the problem-solving spaces under the mapping leads to solving the problem of dynamic reflection, the performance criterion, and the real altitude constraints in the virtual space. It is noteworthy that in designing a path in a newly converted space, the effect of barriers on the formation of flight routes is somehow included in the equations expressed in the virtual space. The results of multiple case studies and numerical optimizations performed for 2D geometrical terrains and obstacles show that the proposed approach is more consistent with the basic flight concepts as well as real-world applications.
