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.

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.

A Probabilistic Theory of Nonlinear Dynamical Systems Based on the Cell State Space Concept

1982 ◽  
Vol 49 (4) ◽  
pp. 895-902 ◽  
Author(s):  
C. S. Hsu
Keyword(s):  
Dynamical Systems ◽  
State Space ◽  
Nonlinear Dynamical Systems ◽  
Global Analysis ◽  
Cell Structure ◽  
The State ◽  
Probabilistic Theory ◽  
Nonlinear Dynamical ◽  
Linear Ordinary Differential Equations ◽  
Highly Nonlinear

Developed in the paper is a probabilistic theory for nonlinear dynamical systems. The theory is based on discretizing the state space into a cell structure and using the cell probability functions to describe the state of a system. Although the dynamical system may be highly nonlinear the probabilistic formulation always leads to a set of linear ordinary differential equations. The evolution of the probability distribution among the cells can then be studied by applying the theory of Markov processes to this set of equations. It is believed that this development possibly offers a new approach to the global analysis of nonlinear systems.

Furnace Modelling Using State Space Representation

2006 ◽  
Vol 3 (1) ◽  
pp. 37
Author(s):  
Razidah Ismail
Keyword(s):  
State Space ◽  
Power Plants ◽  
Controller Design ◽  
Cost Savings ◽  
Combined Cycle ◽  
The State ◽  
Space Representation ◽  
State Variables ◽  
State Space Representation ◽  
Space Modeling

The state space modeling approach was developed to cope with the demand and performance due to the increase in system complexity, which may have multiple inputs and multiple outputs (MIMO). This approach is based on time-domain analysis and synthesis using state variables. This paper describes the development of a state space representation of a furnace system of a combined cycle power plant. Power plants will need to operate optimally so as to stay competitive, as even a small improvement in energy efficiency would involve substantial cost savings. Both the quantitative and qualitative analyses of the state space representation of the furnace system are discussed. These include the responses of systems excited by certain inputs and the structural properties of the system. The analysis on the furnace system showed that the system is bounded input and bounded output stable, controllable and observable. In practice, the state space formulation is very important for numerical computation and controller design, and can be extended for time-varying systems.

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 Furnace Modelling Using State Space Representation

2006 ◽  
Vol 3 (1) ◽  
pp. 37 ◽  
Author(s):  
Razidah Ismail
Keyword(s):  
State Space ◽  
Power Plants ◽  
Controller Design ◽  
Cost Savings ◽  
Combined Cycle ◽  
The State ◽  
Space Representation ◽  
State Variables ◽  
State Space Representation ◽  
Space Modeling

The state space modeling approach was developed to cope with the demand and performance due to the increase in system complexity, which may have multiple inputs and multiple outputs (MIMO). This approach is based on time-domain analysis and synthesis using state variables. This paper describes the development of a state space representation of a furnace system of a combined cycle power plant. Power plants will need to operate optimally so as to stay competitive, as even a small improvement in energy efficiency would involve substantial cost savings. Both the quantitative and qualitative analyses of the state space representation of the furnace system are discussed. These include the responses of systems excited by certain inputs and the structural properties of the system. The analysis on the furnace system showed that the system is bounded input and bounded output stable, controllable and observable. In practice, the state space formulation is very important for numerical computation and controller design, and can be extended for time-varying systems.

scholarly journals Singularity Avoidance Control of a Non-Holonomic Mobile Manipulator for Intuitive Hand Guidance

Robotics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 14 ◽  
Author(s):  
Matthias Weyrer ◽  
Mathias Brandstötter ◽  
Manfred Husty
Keyword(s):  
Flexible Manufacturing ◽  
Manufacturing Systems ◽  
Haptic Feedback ◽  
Controller Design ◽  
Essential Feature ◽  
Mobile Manipulator ◽  
Mobile Manipulators ◽  
Human Machine Interaction ◽  
Natural Approach ◽  
Robot Systems

Mobile manipulators are robot systems capable of combining logistics and manipulation tasks. They thus fulfill an important prerequisite for the integration into flexible manufacturing systems. Another essential feature required for modern production facilities is a user-friendly and intuitive human-machine interaction. In this work the goal of code-less programming is addressed and an intuitive and safe approach to physically interact with such robot systems is derived. We present a natural approach for hand guiding a sensitive mobile manipulator in task space using a force torque sensor that is mount close to the end effector. The proposed control structure is capable of handling the kinematic redundancies of the system and avoid singular arm configurations by means of haptic feedback to the user. A detailed analysis of all possible singularities of the UR robot family is given and the functionality of the controller design is shown with laboratory experiments on our mobile manipulator.

Modeling of CCLP in koryo extract production

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ji Chol ◽  
Ri Jun Il
Keyword(s):  
Process Control ◽  
Medical Care ◽  
State Space ◽  
State Space Model ◽  
The State ◽  
Space Model ◽  
Effective Components ◽  
Counter Current

Abstract The modeling of counter-current leaching plant (CCLP) in Koryo Extract Production is presented in this paper. Koryo medicine is a natural physic to be used for a diet and the medical care. The counter-current leaching method is mainly used for producing Koryo medicine. The purpose of the modeling in the previous works is to indicate the concentration distributions, and not to describe the model for the process control. In literature, there are no nearly the papers for modeling CCLP and especially not the presence of papers that have described the issue for extracting the effective components from the Koryo medicinal materials. First, this paper presents that CCLP can be shown like the equivalent process consisting of two tanks, where there is a shaking apparatus, respectively. It allows leachate to flow between two tanks. Then, this paper presents the principle model for CCLP and the state space model on based it. The accuracy of the model has been verified from experiments made at CCLP in the Koryo Extract Production at the Gang Gyi Koryo Manufacture Factory.

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