Application of the Design For Control Approach for the Integrated Design and Control of Parallel Robots

Author(s):  
Qing Li

To effectively control a complex mechanical structure for precise performance, a model-based type of controller is usually desired. In cases of controlling parallel robots, however, the iterative computation due to the complexity of the dynamic models can result in difficulties in controller implementations and system stability analysis. To avoid this problem, simplified dynamic models can be obtained through approximation, nevertheless, performance accuracy will suffer due to simplification. This paper suggests applying the effective Design For Control (DFC) approach to handle this problem. The underlying idea of the DFC approach is that, no matter how complex a system is, as long as its mechanical structure can be judiciously designed such that it results in a simple dynamic model, a simple control algorithm may be good enough for a satisfactory control performance. Through out the discussion in the paper, the integrated design and control of a two DOF parallel robot is studied as an illustration example. Experimental validation has demonstrated the effectiveness of the DFC approach.

Robotica ◽  
2005 ◽  
Vol 24 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Qing Li

Due to the demands from the robotic industry, robot structures have evolved from serial to parallel. The control of parallel robots for high performance and high speed tasks has always been a challenge to control engineers. Following traditional control engineering approaches, it is possible to design advanced algorithms for parallel robot control. These approaches, however, may encounter problems such as heavy computational load and modeling errors, to name it a few. To avoid heavy computation, simplified dynamic models can be obtained by applying approximation techniques, nevertheless, performance accuracy will suffer due to modeling errors. This paper suggests applying an integrated design and control approach, i.e., the Design For Control (DFC) approach, to handle this problem. The underlying idea of the DFC approach can be illustrated as follows: Intuitively, a simple control algorithm can control a structure with a simple dynamic model quite well. Therefore, no matter how sophisticate a desired motion task is, if the mechanical structure is designed such that it results in a simple dynamic model, then, to design a controller for this system will not be a difficult issue. As such, complicated control design can be avoided, on-line computation load can be reduced and better control performance can be achieved. Through out the discussion in the paper, a 2 DOF parallel robot is redesigned based on the DFC concept in order to obtain a simpler dynamic model based on a mass-balancing method. Then a simple PD controller can drive the robot to achieve accurate point-to-point tracking tasks. Theoretical analysis has proven that the simple PD control can guarantee a stable system. Experimental results have successfully demonstrated the effectiveness of this integrated design and control approach.


Robotica ◽  
1990 ◽  
Vol 8 (2) ◽  
pp. 105-109 ◽  
Author(s):  
F. Pierrot ◽  
C. Reynaud ◽  
A. Fournier

SummaryThe DELTA parallel robot, designed by an EPFL (Ecole Polytechnique Fédérale de Lausanne) research team, is a mechanical structure which has the advantage of parallel robots and ease of serial robots modeling. This paper presents solutions for a complete modeling of the DELTA parallel robot (direct and inverse kinematics, inverse statics, inverse dynamics), with few arithmetic and trigonometric operations. Our method is based on a satisfactory choice of kinematic parameters and on a few restricting hypotheses for the static and dynamic models. We give some details of each model, we present some computation results and we put the emphasis on some particular points, showing the capabilities of this mechanical structure.


2010 ◽  
Vol 166-167 ◽  
pp. 457-462
Author(s):  
Dan Verdes ◽  
Radu Balan ◽  
Máthé Koppány

Parallel robots find many applications in human-systems interaction, medical robots, rehabilitation, exoskeletons, to name a few. These applications are characterized by many imperatives, with robust precision and dynamic workspace computation as the two ultimate ones. This paper presents kinematic analysis, workspace, design and control to 3 degrees of freedom (DOF) parallel robots. Parallel robots have received considerable attention from both researchers and manufacturers over the past years because of their potential for high stiffness, low inertia and high speed capability. Therefore, the 3 DOF translation parallel robots provide high potential and good prospects for their practical implementation in human-systems interaction.


Author(s):  
Daniel G. Cole

This paper discusses adaptive identification and control (AID&C) techniques to enable automated online identification and control of SMRs. Adaptive system ID allows engineers to rapidly measure system dynamics, calibrate sensors channels, determine loop processes, and quantify actuator authority for the various reactor control loops. Adaptive control can automatically tune these loops and adjust plant processes to optimize conditions for peak performance and power production. Another advantage of the adaptive ID and control approach is that these tools can be used during reactor operation to monitor active and passive components. Adaptive system ID techniques are used to measure loop-transfer characteristics. Presented is a practical approach that uses adaptive model-matching tools to identify the coprime factors of the local loops. This has the advantage over model based approaches since coprime factors can be identified on the real system using real data. Adaptive control enables auto-tuning of controller parameters to meet operational specifications. Using the coprime factors, all controllers that stabilize the plant can be parametrized by a free Q-parameter that can be changed to meet control system objectives and improve performance, and the tuning is performed using adaptive techniques. The controller architecture presented provides several desirable and necessary features: e.g., a default fail-safe mode of operation, stability in the presence of communications failures, guaranteed stability, and robustness. An advantage of the adaptive structure presented here is that control system stability can be guaranteed, even during adaptation by ensuring certain norm conditions on the Q-parameter and estimated plant uncertainty. More importantly, the Q-parameter can be monitored during operation, providing a real-time estimate of the changes in the plant resulting from changes in the reactor itself. This signal monitors the dynamics of each loop, providing information about the reactor from the perspective of the control process. Online monitoring using AID&C can be used to better track control system transients that result in reactor trip, thus avoiding undesirable reactor trips and diversion events. And, there is a potential that the system can better adapt to changing operating conditions during plant transients including load following procedures.


Author(s):  
A. Zubizarreta ◽  
E. Portillo ◽  
I. Cabanes ◽  
M. Marcos ◽  
Ch. Pinto

Due to their high performance when executing high-speed and accurate tasks, parallel robots have became the focus of many researchers and companies. However, exploiting the full potential of these robots requires a correct mechatronic design, in which the designed mechanism has to be controlled by a suitable control law in order to achieve the maximum performance. In this paper a novel Validation and Control Environment (VALIDBOT) is proposed as a support for the control design and experimental testing stages of these robots. The proposed open and flexible environment is designed to meet rapid prototyping requirements, offering a high level framework for both students and researchers. The capabilities of the environment are illustrated with an application case based on a 5R parallel robot prototype in which a modified CTC controller is tested.


Author(s):  
C-Y Chen ◽  
T-C G Chiu

In this paper, an integrated approach has been proposed to the design and control of the media advance system in thermal inkjet printers. Using H∞ analysis and synthesis approach, the effects of design tolerance and system disturbance on the achievable performance is characterized. The media advance system of thermal inkjet printers is used to illustrate the effectiveness of the proposed approach. The benefit of using an integrated design and control approach has also been discussed. It has been verified that this integrated control will offer the better performance at the lower cost for the inkjet printers used.


1982 ◽  
Vol 19 (03) ◽  
pp. 532-545 ◽  
Author(s):  
Michael Kolonko

The optimal control of dynamic models which are not completely known to the controller often requires some kind of estimation of the unknown parameters. We present conditions under which a minimum contrast estimator will be strongly consistent independently of the control used. This kind of estimator is appropriate for the adaptive or ‘estimation and control' approach in dynamic programming under uncertainty. We consider a countable-state Markov renewal model and we impose bounding and recurrence conditions of the so-called Liapunov type.


Author(s):  
James P. Schmiedeler ◽  
Eric R. Westervelt ◽  
Adam R. Dunki-Jacobs

This paper introduces a methodology for the integration of mechanical and control system design of planar biped robots. The control approach is a procedure for the systematic design, analysis, and performance enhancement of controllers that induce provably stable dynamic walking in planar bipeds. Iterative application of this procedure with variations in the mechanical parameters of the biped model enables a designer to drive design changes based upon analytical metrics of stability and efficiency. The outcomes are a dynamically-informed mechanical design and controllers that maximally exploit the unforced dynamics of that design. This methodology has been applied to the design and construction of the prototype biped BIRT (BIped Robot with Three legs). BIRT is a planar biped whose two outside legs are slaved by means of control to act together. The paper provides a detailed description of BIRT’s mechanical system.


2012 ◽  
Vol 162 ◽  
pp. 575-582 ◽  
Author(s):  
Ciprian Lapusan ◽  
Vistrian Maties ◽  
Olimpiu Hancu ◽  
Ciprian Rad

The article proposes a new mechatronic integrated design approach for a robotic system. The proposed method uses modern methods like model based design, rapid control prototyping and hardware in the loop simulations in the development process. Using this method a six DOF teleoperated parallel robot is developed, the results are presented in the paper.


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