Differentially Flat Designs of Mobile Vehicles With Under-Actuated Manipulator Arms

2007 ◽  
Author(s):  
Ji-Chul Ryu ◽  
Vivek Sangwan ◽  
Sunil K. Agrawal
Keyword(s):  
Controller Design ◽  
Mobile Manipulator ◽  
Differential Flatness ◽  
Combined System ◽  
Planning And Control ◽  
Mobile Vehicle ◽  
Highly Nonlinear ◽  
Manipulator Arm ◽  
Point To Point ◽  
And Control

Differential flatness has been investigated in the context of mobile vehicles for planning and control of their motions. In these models, the wheels are considered to be non-slipping, i.e., the system dynamics is subject to non-holonomic constraints. If a manipulator arm is mounted on such a mobile vehicle, the dynamics becomes highly nonlinear due to the nonlinear coupling between the motions of the mobile vehicle and the manipulator arm. A challenging question is how to perform point-to-point motions of such a system in the state space of the mobile manipulator. If some of the actuators are absent in the mechanical arm, the mobile manipulator becomes under-actuated and consequently even harder to plan and control. This paper presents a methodology for design of mobile vehicles, mounted with under-actuated manipulators operating in a horizontal plane, such that the combined system is differentially flat. In this paper, we show that by appropriate inertia distribution of the links and addition of torsion springs at the joints, a range of under-actuated designs are possible where the underactuated mobile manipulator system is differentially flat. The differential flatness property allows to efficiently solve the problem of trajectory planning and feedback controller design for point to point motions of the system. The proposed method is illustrated by the example of a mobile vehicle with under-actuated three-link manipulator.

Differentially Flat Designs of Underactuated Mobile Manipulators

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Ji-Chul Ryu ◽  
Vivek Sangwan ◽  
Sunil K. Agrawal
Keyword(s):  
State Space ◽  
Controller Design ◽  
The State ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Combined System ◽  
Mobile Vehicle ◽  
Highly Nonlinear ◽  
Point To Point ◽  
Challenging Question

This paper presents a methodology for design of mobile vehicles, mounted with underactuated manipulators operating in a horizontal plane, such that the combined system is differentially flat. A challenging question of how to perform point-to-point motions in the state space of such a highly nonlinear system, in spite of the absence of some actuators in the arm, is answered in this paper. We show that, by appropriate inertia distribution of the links and addition of torsion springs at the joints, a range of underactuated designs is possible, where the underactuated mobile manipulator system is differentially flat. The differential flatness property allows one to efficiently solve the problem of trajectory planning and feedback controller design for point-to-point motions in the state space. The proposed method is illustrated by the example of a mobile vehicle with an underactuated three-link manipulator.

Differential-Flatness-Based Planning and Control of a Wheeled Mobile Manipulator—Theory and Experiment

2011 ◽  
Vol 16 (4) ◽  
pp. 768-773 ◽  
Author(s):  
Chin Pei Tang ◽  
Patrick T. Miller ◽  
Venkat N. Krovi ◽  
Ji-Chul Ryu ◽  
Sunil K. Agrawal
Keyword(s):  
Mobile Manipulator ◽  
Differential Flatness ◽  
Planning And Control ◽  
And Control ◽  
Theory And Experiment

Kinematic Control of Nonholonomic Wheeled Mobile Manipulator: A Differential Flatness Approach

2008 ◽  
Author(s):  
Chin Pei Tang ◽  
Patrick T. Miller ◽  
Venkat N. Krovi ◽  
Ji-Chul Ryu ◽  
Sunil K. Agrawal
Keyword(s):  
Motion Planning ◽  
Kinematic Model ◽  
Pole Placement ◽  
Mobile Manipulator ◽  
Differential Flatness ◽  
Placement Problem ◽  
Planning And Control ◽  
Polynomial Curve ◽  
Point Motion ◽  
Point To Point

This paper presents an integrated motion planning and control framework for a nonholonomic wheeled mobile manipulator (WMM) system taking advantage of the (differential) flatness property. We first develop the kinematic model of the system and analyze its flatness properties. Subsequently, a statically feedback linearizable system description is developed by appropriately choosing the flat outputs. Motion-planning can now be achieved by polynomial curve fitting to satisfying the terminal conditions in the flat output space while control design reduces to a pole-placement problem for a linear system. A case study of point-to-point motion is considered to study the effectiveness of pose stabilization in the WMM. The simulation and experimental results highlight the ease-of-implementation of proposed method for online real-time integrated motion-planning/control within a hardware-in-the-loop (HIL) electro-mechanical testing.

scholarly journals Pick and Place Operations in Logistics Using a Mobile Manipulator Controlled with Deep Reinforcement Learning

2019 ◽  
Vol 9 (2) ◽  
pp. 348 ◽  
Author(s):  
Ander Iriondo ◽  
Elena Lazkano ◽  
Loreto Susperregi ◽  
Julen Urain ◽  
Ane Fernandez ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Path Planning ◽  
Mobile Manipulator ◽  
Complex Tasks ◽  
Complex Control ◽  
Planning And Control ◽  
Pick And Place ◽  
Policy Gradient ◽  
Point To Point ◽  
And Control

Programming robots to perform complex tasks is a very expensive job. Traditional path planning and control are able to generate point to point collision free trajectories, but when the tasks to be performed are complex, traditional planning and control become complex tasks. This study focused on robotic operations in logistics, specifically, on picking objects in unstructured areas using a mobile manipulator configuration. The mobile manipulator has to be able to place its base in a correct place so the arm is able to plan a trajectory up to an object in a table. A deep reinforcement learning (DRL) approach was selected to solve this type of complex control tasks. Using the arm planner’s feedback, a controller for the robot base is learned, which guides the platform to such a place where the arm is able to plan a trajectory up to the object. In addition the performance of two DRL algorithms ((Deep Deterministic Policy Gradient (DDPG)) and (Proximal Policy Optimisation (PPO)) is compared within the context of a concrete robotic task.

Differential Flatness-Based Robust Control of a Two-Wheeled Mobile Robot in the Presence of Slip

2008 ◽  
Author(s):  
Ji-Chul Ryu ◽  
Sunil K. Agrawal
Keyword(s):  
Robust Control ◽  
Mobile Robot ◽  
Wheeled Mobile Robot ◽  
Differential Flatness ◽  
Robust Controllers ◽  
Robust Controller ◽  
Planning And Control ◽  
Tracking Controllers ◽  
Simulation Results ◽  
And Control

In this paper, we present two robust trajectory-tracking controllers for a differentially driven two-wheeled mobile robot using its kinematic and dynamic model in the presence of slip. The structure of the differential flatness-based controller, which is an integrated framework for planning and control, is extended in this paper to account for slip disturbances by adding a corrective control term. Simulation results for both kinematic and dynamic controllers are presented to demonstrate the effectiveness of the robust controllers. Experiments with the kinematic controller were conducted to validate the performance of the robust controller. The simulation and experimental results show that the robust controllers are very effective in the presence of slip.

Trajectory control of a mobile manipulator in the presence of base disturbance

SIMULATION ◽  
2018 ◽  
Vol 95 (6) ◽  
pp. 529-543 ◽  
Author(s):  
RV Ram ◽  
PM Pathak ◽  
SJ Junco
Keyword(s):  
Mobile Robot ◽  
Dynamic Models ◽  
Control Strategies ◽  
Effective Control ◽  
Mobile Manipulator ◽  
Dynamic Interactions ◽  
Additional Task ◽  
Manipulator Arm ◽  
And Control ◽  
Base Disturbance

A mobile manipulator is typically an assembly of a mobile robot base and an on-board manipulator arm. As the manipulator arm is mounted over the mobile robot base, the controller has the additional task of taking care of the disturbances of the mobile robot due to the dynamic interactions between the mobile robot base and manipulator arm. In the present work, dynamic models for the manipulator arm and an omni-wheeled mobile robot base were developed separately and then both were combined. Two control strategies, namely only manipulator arm control (OMAC) and simultaneous manipulator and base control (SMBC) were developed for the effective control of tip trajectory. In both strategies, an amnesia recovery coupled with classical proportional integral and derivative (PID) control was used. The bond graph methodology was used for the development of the dynamic model and control for the mobile manipulator. Simulation results are presented to illustrate the efficacy of the two control strategies.

Motion Planning and Control of Artificial Muscle Actuated Underwater Vehicle Using Nonlinear Neural Oscillator

2007 ◽  
Author(s):  
Joon Soo Lee ◽  
Woosoon Yim ◽  
Kwang J. Kim
Keyword(s):  
Motion Planning ◽  
Controller Design ◽  
Artificial Muscle ◽  
Underwater Vehicle ◽  
Open Loop ◽  
Neural Oscillator ◽  
Aquatic Environments ◽  
Metal Composite ◽  
Planning And Control ◽  
And Control

In this paper, we introduce the motion planning and control strategy for the underwater vehicle actuated by a soft artificial muscle actuator. The artificial muscle used for this underwater application is an Ionic Polymer Metal Composite (IPMC) which can generate bending motion in aquatic environments. In this research, the double ring structured nonlinear neural oscillator is proposed for the undulatory motion in the actuator. The overall dynamic model of the flexible IPMC actuator including its fluid interaction terms is used for the motion planning and open-loop controller design. The IPMC used in this study is a patterned or segmented type where the electrode surface of the actuator is encoded such that each segment can be controlled independently for effectively generating an undulatory motion in the water. Computer simulations show that the proposed neural oscillator based controller can be effectively used for the underwater locomotion applications, and can be extended to the closed-loop controller where the precise maneuver is needed in the unstructured aquatic environments.

scholarly journals Collision-Free Trajectory Planning for Mobile Manipulators Subject to Control Constraints

2014 ◽  
Vol 61 (1) ◽  
pp. 35-55
Author(s):  
Grzegorz Pajak ◽  
Iwona Pajak
Keyword(s):  
Three Dimensional ◽  
Nonholonomic Constraints ◽  
Mobile Manipulator ◽  
Reference Trajectory ◽  
Mobile Manipulators ◽  
Control Constraints ◽  
Redundancy Resolution ◽  
Manipulability Measure ◽  
Point To Point ◽  
And Control

Abstract A method of planning collision-free trajectory for a mobile manipulator tracking a line section path is presented. The reference trajectory of a mobile platform is not needed, mechanical and control constraints are taken into account. The method is based on a penalty function approach and a redundancy resolution at the acceleration level. Nonholonomic constraints in a Pfaffian form are explicitly incorporated to the control algorithm. The problem is shown to be equivalent to some point-to-point control problem whose solution may be easier determined. The motion of the mobile manipulator is planned in order to maximise the manipulability measure, thus to avoid manipulator singularities. A computer example involving a mobile manipulator consisting of a nonholonomic platform (2,0) class and a 3 DOF RPR type holonomic manipulator operating in a three-dimensional task space is also presented.

scholarly journals Rotor-Flying Manipulator: Modeling, Analysis, and Control

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Bin Yang ◽  
Yuqing He ◽  
Jianda Han ◽  
Guangjun Liu
Keyword(s):  
Controller Design ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Combined System ◽  
Underwater Robots ◽  
Modeling Analysis ◽  
Full State Feedback ◽  
Lqr Controller ◽  
Linearized Model ◽  
And Control

Equipping multijoint manipulators on a mobile robot is a typical redesign scheme to make the latter be able to actively influence the surroundings and has been extensively used for many ground robots, underwater robots, and space robotic systems. However, the rotor-flying robot (RFR) is difficult to be made such redesign. This is mainly because the motion of the manipulator will bring heavy coupling between itself and the RFR system, which makes the system model highly complicated and the controller design difficult. Thus, in this paper, the modeling, analysis, and control of the combined system, called rotor-flying multijoint manipulator (RF-MJM), are conducted. Firstly, the detailed dynamics model is constructed and analyzed. Subsequently, a full-state feedback linear quadratic regulator (LQR) controller is designed through obtaining linearized model near steady state. Finally, simulations are conducted and the results are analyzed to show the basic control performance.

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