scholarly journals Robotic Forklift for Stacking Multiple Pallets with RGB-D Cameras

2021 ◽  
Vol 33 (6) ◽  
pp. 1265-1273
Author(s):  
Ryosuke Iinuma ◽  
Yusuke Hori ◽  
Hiroyuki Onoyama ◽  
Yukihiro Kubo ◽  
Takanori Fukao ◽  
...  
Keyword(s):  
Path Following ◽  
Region Growing ◽  
Complex Problem ◽  
Control Law ◽  
Depth Cameras ◽  
Depth Data ◽  
Sensor Position ◽  
Path Following Control ◽  
Position And Orientation ◽  
And Storage

We propose a robotic forklift system for stacking multiple mesh pallets. The stacking of mesh pallets is an essential task for the shipping and storage of loads. However, stacking, the placement of pallet feet on pallet edges, is a complex problem owing to the small sizes of the feet and edges, leading to a complexity in the detection and the need for high accuracy in adjusting the pallets. To detect the pallets accurately, we utilize multiple RGB-D (RGB Depth) cameras that produce dense depth data under the limitations of the sensor position. However, the depth data contain noise. Hence, we implement a region growing-based algorithm to extract the pallet feet and edges without removing them. In addition, we design the control law based on path following control for the forklift to adjust the position and orientation of two pallets. To evaluate the performance of the proposed system, we conducted an experiment assuming a real task. The experimental results demonstrated that the proposed system can achieve a stacking operation with a real forklift and mesh pallets.

Non-Linear Path-Following Control of Micro-AUV

2014 ◽  
Vol 1006-1007 ◽  
pp. 599-603
Author(s):  
Xing Ji ◽  
Lei Zhang ◽  
Jian Cao ◽  
Shan Ma
Keyword(s):  
Control Method ◽  
Path Following ◽  
Lyapunov Stability Theory ◽  
Linear Feedback ◽  
Control Law ◽  
Linear Feedback Control ◽  
Path Following Control ◽  
Virtual Target ◽  
Non Linear ◽  
Following Error

A novel path-following control method of under-actuated AUV is proposed in this paper. Under the Serret-Frenet coordinate system, dynamics equations of path-following error were established based on virtual target AUV. And then combined with dynamics equations of AUV, controller was designed based on Lyapunov stability theory and backstepping technique. Simulation results showed that path-following error could converge to zero rapidly by using the proposed non-linear feedback control law, to make the AUV navigate along the referenced path.

scholarly journals Underactuated USV Path Following Mechanism Based on the Cascade Method

2021 ◽  
Author(s):  
Mingzhen Lin ◽  
Zhiqiang Zhang ◽  
Yandong Pang ◽  
Hongsheng Lin ◽  
Qing Ji
Keyword(s):  
Tracking Error ◽  
Path Following ◽  
Ocean Current ◽  
Control Law ◽  
Guidance Law ◽  
Path Following Control ◽  
Heading Control ◽  
Velocity Constraints ◽  
The Stability ◽  
Rudder Angle

Abstract The path following control under disturbance was studied for an underactuated unmanned surface vehicle (USV) subject to the rudder angle and velocity constraints. For this reason, a variable look-ahead integral line-of-sight (LOS) guidance law was designed on the basis of the disturbance estimation and compensation, and a cascade path following control system was created following the heading control law based on the model prediction. Firstly, the guidance law was designed using the USV three-degree-of-freedom (DOF) motion model and the LOS method, while the tracking error state was introduced to design the real-time estimation of disturbance observer and compensate for the influence of ocean current. Moreover, the stability of the system was analyzed. Secondly, sufficient attention was paid to the rudder angle and velocity constraints and the influence of system delay and other factors in the process of path following when the heading control law was designed with the USV motion response model and the model predictive control (MPC). The moving horizon optimization strategy was adopted to achieve better dynamic performance, effectively overcome the influence of model and environmental uncertainties, and further prove the stability of the control law. Thirdly, a simulation experiment was carried out to verify the effectiveness and advancement of the proposed algorithm. Fourthly, the “Sturgeon 03” USV was used in the lake test of the proposed control algorithm to prove its feasibility in the engineering practices.

scholarly journals Path Following Control of the Underactuated USV Based On the Improved Line-of-Sight Guidance Algorithm

2017 ◽  
Vol 24 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Tao Liu ◽  
Zaopeng Dong ◽  
Hongwang Du ◽  
Lifei Song ◽  
Yunsheng Mao
Keyword(s):  
Lyapunov Stability ◽  
Tangential Velocity ◽  
Path Following ◽  
Lyapunov Stability Theory ◽  
Line Of Sight ◽  
Coordinate Frame ◽  
Control Law ◽  
Path Following Control ◽  
Guidance Algorithm ◽  
Following Error

Abstract The path following control problem of the underactuated unmanned surface vessel (USV) is studied in this paper. An improved line-of-sight (LOS) guidance algorithm is proposed which can adjust adaptively based on the path following error. The global asymptotically stable path following controller is designed based on the nonlinear backstepping method and the Lyapunov stability theory. Firstly, the USV path following error model is established in the Serret-Frenet (SF) coordinate frame. The path following error in the inertial coordinate frame is transformed into the SF coordinate frame, which is used to define the path following control problem. Secondly, inspired by the traditional LOS guidance algorithm, the longitudinal path following error in the SF coordinate frame is introduced into the improved LOS guidance algorithm. This allows the algorithm to adjust adaptively to the desired path. Thirdly, in order to solve the underactuated problem of the USV path following control system, the tangential velocity of the desired path is designed as a virtual input. The underactuated problem is converted to a virtual fully actuated problem by designing the virtual control law for the tangential velocity. Finally, by combining backstepping design principles and the Lyapunov stability theory, the longitudinal thrust control law and the yaw torque control law are designed for the underactuated USV. Meanwhile, the global asymptotic stability of the path following error is proved. Simulation experiments demonstrate the effectiveness and reliability of the improved LOS guidance algorithm and the path following controller.

Nonsingular Serret–Frenet Based Path Following Control for an Underactuated Surface Vessel

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Jawhar Ghommam ◽  
Faïçal Mnif ◽  
Abederraouf Benali ◽  
Nabil Derbel
Keyword(s):  
Direct Method ◽  
Path Following ◽  
Ocean Current ◽  
Control Law ◽  
High Fidelity Simulation ◽  
Lyapunov Direct Method ◽  
Path Following Control ◽  
Definition Of ◽  
Along Track ◽  
Surface Vessel

In this paper we develop a new control law to steer an underactuated surface vessel along a predefined path at a constant forward speed controlled by the main thruster system. The methodology is based on the Serret–Frenet formulation to represent the ship kinematics in terms of path parameters, which allows for convenient definition of cross and along track error. Furthermore, our approach for path following overcomes the stringent initial condition constraints. This paper also addresses the path following with environmental disturbances induced by wave, wind, and ocean-current. The proposed controller is designed based on the Lyapunov direct method and backstepping technique. The closed loop path following errors is proven to be uniform ultimate bounded. Results are demonstrated by high fidelity simulation.

Yaw-rate-tracking-based Automated Vehicle Path Following: An MRAC Methodology with A Closed-Loop Reference Model

2021 ◽  
pp. 1-17
Author(s):  
Xingyu Zhou ◽  
Zejiang Wang ◽  
Heran Shen ◽  
Junmin Wang
Keyword(s):  
Closed Loop ◽  
Reference Model ◽  
Path Following ◽  
Control Law ◽  
Hardware In The Loop ◽  
Control Loops ◽  
Path Following Control ◽  
Speed Up ◽  
Vehicle Path ◽  
Model Reference Adaptive

Abstract Concerning automated vehicles, various path-following controllers have been designed by the model reference adaptive control (MRAC) approach. Through appropriate Lyapunov redesigns, asymptotical stability and signal boundedness are ensured for the path-tracking control loops. However, transient behaviors of the closed-loop responses are seldom considered in the context of MRAC synthesis. To bridge the foregoing gap, a closed-loop reference model-based MRAC, which yields an improved transient performance compared with a traditional MRAC, is exploited to synthesize a vehicular path following control law. Besides, an infinitely differentiable projection operator is complemented to the control parameters' adaptation schemes for estimation speed-up and robustness enhancement. Hardware-in-the loop experiments are used to evaluate the proposed method and to demonstrate its improvement over some conventional MRAC designs.

scholarly journals Path Following Control of Fully Actuated Autonomous Underwater Vehicle Based on LADRC

2018 ◽  
Vol 25 (4) ◽  
pp. 39-48 ◽  
Author(s):  
Habib Choukri Lamraoui ◽  
Zhu Qidan
Keyword(s):  
Real Time ◽  
Tracking Control ◽  
Autonomous Underwater Vehicle ◽  
Path Following ◽  
Underwater Vehicle ◽  
Control Law ◽  
External Disturbances ◽  
Path Following Control ◽  
State Measurement ◽  
Full State

Abstract This paper presents an active disturbances rejecter controller (ADRC) for position and path following control of a fully actuated autonomous underwater vehicle (AUV). The unmodeled, undesirable dynamics and disturbances reduce the performances of classical controllers and complicate the design of appropriate and efficient controllers. In the proposed approach, the different modeling complexities; such as uncertain parameters, non-linearities, and external disturbances are considered all as a part of disturbance which is estimated in real-time by the extended state observer ESO, and effectively compensated from the control law. The ESO is also able to estimate the position and velocity of the system in real-time, in case where the full state measurement of the AUV is not possible during experiments. Computer simulations demonstrate the high ability of the AUV tracking control based on ADRC, to follow the desired trajectory in the horizontal plane and space with high precision, and showed high robustness and efficiency in rejecting the external and internal disturbances caused by significant changes in parameters of the system, and the added position disturbances.

scholarly journals Motion Control of a 4WS4WD Path-Following Vehicle: Further Studies on Steering and Driving Models

2021 ◽  
Vol 2021 ◽  
pp. 1-25
Author(s):  
Zhonghua Zhang ◽  
Caijin Yang ◽  
Weihua Zhang ◽  
Yanhai Xu ◽  
Yiqiang Peng ◽  
...  
Keyword(s):  
Motion Control ◽  
Deep Level ◽  
Dynamic Environment ◽  
Path Following ◽  
Complex Problem ◽  
Level Control ◽  
Control Models ◽  
Path Following Control ◽  
Vehicle Path ◽  
Vehicle Dynamic Model

Further research on motion control of a 4WS4WD path-following vehicle is carried out in this paper. Focuses are placed on understanding and testing the vehicle path-following control models developed previously at a deep level. Control models are in relation to parameters introduced, and the effects of these parameters are discovered. Control models are interpreted by dynamic simulation using a 3DOF vehicle model with three cases. Three kinds of planned paths are considered in these cases to test control performances, which include the straight, circular, and sinusoidal paths. Interesting dynamic results are obtained and analyzed qualitatively, e.g., various steering modes. Simulation studies are extended with consideration of a fine vehicle dynamic model established in CarSim and a complex path composed of straight and curved segments. Control models are examined in a complex problem, and results obtained show that they are validated with robustness in dynamic environment.

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