1,148 research outputs found
Coverage Path Planning And Control For Autonomous Mobile Robots
Coverage control has many applications such as security patrolling, land mine detectors, and automatic vacuum cleaners. This Thesis presents an analytical approach for generation of control inputs for a non-holonomic mobile robot in coverage control. Neural Network approach is used for complete coverage of a given area in the presence of stationary and dynamic obstacles. A complete coverage algorithm is used to determine the sequence of points. Once the sequences of points are determined a smooth trajectory characterized by fifth order polynomial having second order continuity is generated. And the slope of the curve at each point is calculated from which the control inputs are generated analytically. Optimal trajectory is generated using a method given in research literature and a qualitative analysis of the smooth trajectory is done. Cooperative sweeping of multirobots is achieved by dividing the area to be covered into smaller areas depending on the number of robots. Once the area is divided into sub areas, each robot is assigned a sub area for cooperative sweeping
Comparative analysis of firefly algorithm for solving optimization problems
Firefly algorithm was developed by Xin-She Yang [1] by taking inspiration from flash light signals which is the source of attraction among fireflies for potential mates. All the fireflies are unisexual and attract each other according to the intensities of their flash lights. Higher the flash light intensity, higher is the power of attraction and vice versa. For solving optimization problem, the brightness of flash is associated with the fitness function to be optimized. The light intensity I (r) of a firefly at distance r is given by equation (1
Multi-layer approach to motion planning in obstacle rich environment
A widespread use of robotic technology in civilian and military applications has
generated a need for advanced motion planning algorithms that are real-time implementable.
These algorithms are required to navigate autonomous vehicles through
obstacle-rich environments. This research has led to the development of the multilayer
trajectory generation approach. It is built on the principle of separation of
concerns, which partitions a given problem into multiple independent layers, and addresses
complexity that is inherent at each level. We partition the motion planning
algorithm into a roadmap layer and an optimal control layer. At the roadmap layer,
elements of computational geometry are used to process the obstacle rich environment
and generate feasible sets. These are used by the optimal control layer to generate
trajectories while satisfying dynamics of the vehicle. The roadmap layer ignores the
dynamics of the system, and the optimal control layer ignores the complexity of the
environment, thus achieving a separation of concern. This decomposition enables
computationally tractable methods to be developed for addressing motion planning
in complex environments. The approach is applied in known and unknown environments.
The methodology developed in this thesis has been successfully applied to a 6
DOF planar robotic testbed. Simulation results suggest that the planner can generate
trajectories that navigate through obstacles while satisfying dynamical constraints
Embodied Footprints: A Safety-guaranteed Collision Avoidance Model for Numerical Optimization-based Trajectory Planning
Numerical optimization-based methods are among the prevalent trajectory
planners for autonomous driving. In a numerical optimization-based planner, the
nominal continuous-time trajectory planning problem is discretized into a
nonlinear program (NLP) problem with finite constraints imposed on finite
collocation points. However, constraint violations between adjacent collocation
points may still occur. This study proposes a safety-guaranteed
collision-avoidance modeling method to eliminate the collision risks between
adjacent collocation points in using numerical optimization-based trajectory
planners. A new concept called embodied box is proposed, which is formed by
enlarging the rectangular footprint of the ego vehicle. If one can ensure that
the embodied boxes at finite collocation points are collide-free, then the ego
vehicle's footprint is collide-free at any a moment between adjacent
collocation points. We find that the geometric size of an embodied box is a
simple function of vehicle velocity and curvature. The proposed theory lays a
foundation for numerical optimization-based trajectory planners in autonomous
driving.Comment: 12 pages, 13 figure
Obround trees: Sparsity enhanced feedback motion planning of differential drive robotic systems
© 2021 Turkiye Klinikleri. All rights reserved.Robot motion planning & control is one of the most critical and prevalent problems in the robotics community. Even though original motion planning algorithms had relied on "open-loop" strategies and policies, researchers and engineers have been focusing on feedback motion planning and control algorithms due to the uncertainties, such as process and sensor noise of autonomous robotic applications. Recently, several studies proposed some robust feedback motion planning strategies based on sparsely connected safe zones. In this class of planning and control policies, local control policy inside a single zone computes and feeds the control actions that can drive the robot to a different connected region while guaranteeing that the robot never exceeds the boundaries of the active area until convergence. While most of these studies apply only to holonomic robotic models, a recent motion planning method (RCT) can solve the motion planning and navigation problems for unicycle like robotic systems based on a randomly connected circular region tree. In this paper, we propose a new/updated feedback motion planning algorithm that substantially enhances the sparsity, computational feasibility, and input effort compared to their methodology. The new algorithm generates a sparse neighborhood tree as a set of connected obround zones. Obround regions cover larger areas inside the environment, thus leads to a more sparse tree structure. During navigation, we modify the nonlinear control policy adopted in RCT method to handle the obround shaped zones. The feedback control policy navigates the robot model from one obround zone to the adjacent area in the tree structure, ensuring it stays inside the active region's boundaries and asymptotically reaches the connected obround. We demonstrate the effectiveness and validity of the algorithm on simulation studies. Our Monte Carlo simulations show that our enhancement to the original algorithm probabilistically improves the sparsity, and produces smoother trajectories compared to two motion planning algorithms that rely on sampling based neighborhood structures
Magnetic suspension turbine flow meter
Measurement of liquid flow in certain area such as industrial plant is in critical. Inaccurate measurement can cause serious result. Most of the liquid flow are using Bernoulli principle‘s but in turbine flow meter the flow rate is determine differently by using kinetic energy. Turbine flow meter is one of flow rate transducer that widely used in metallurgical, petroleum, chemical and other industrial and agricultural areas, as shown in Figure 1.1. It is present as high precision of flow meter and when fluid flow troughs it the impeller that faces the fluid will rotate due to flow force exist. The rotation speed is directly proportional to the speed of fluid. During the process, the working states of impeller and bearing are very complicated due the interactive effects from the fluid axial thrust, impeller rotating, and static and dynamic components. In current turbine flow meter design, the common material use for meter bulk body is 1Cr18Ni9Ti, while for the blade 2Gr13 are used. Axis and bearing are made from stainless steel or carbide alloy. The space between the axis and bearing determines it minimum flow rate and life span, and also determines its measurement range (1:10~1:15 - maximum flow rate to minimum flow rate). Since the turbine has movable parts it can produce friction between the axis and ring during the operation. This will cause accuracy of the measurement decrease and can damage the impeller blade. In this research, the friction can be reduced by adopting the principle of magnetic suspension. Rotating shaft will levitate in the magnetic field due to the forces. Friction coefficient reduced because of rotating shaft rotates without abrasion and mechanical contact in space
- …