Illustrating man-machine motion analogy in robotics - The handwriting problem

Potkonjak, Veljko; Tzafestas, Spyros G.; Kostic, D Dragan; Djordjević, Goran S.; Rasic, M.

doi:10.1109/mra.2003.1191709

Cited by 25 publications

(13 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It consists of writing a sequence of letters that can be described piecewise in closed-form, with the possibility of imposing an arbitrary velocity profile. Freedom in prescribing the velocity profile enables one to pose very demanding dynamic tasks, which is confirmed by the analysis carried out in [43]. The piecewise closed-form representation and the possibility of imposing the velocity can be exploited for a rigorous verification of robot kinematic and dynamic models.…”

Section: B Model Verification With a Writing Taskmentioning

confidence: 79%

See 1 more Smart Citation

Modeling and Identification for High-Performance Robot Control: An RRR-Robotic Arm Case Study

Kostic

Jager

Steinbuch

et al. 2004

IEEE Trans. Contr. Syst. Technol.

Self Cite

View full text Add to dashboard Cite

This paper explains a procedure for getting models of robot kinematics and dynamics that are appropriate for robot control design. The procedure consists of the following steps: 1) derivation of robot kinematic and dynamic models and establishing correctness of their structures; 2) experimental estimation of the model parameters; 3) model validation; and 4) identification of the remaining robot dynamics, not covered with the derived model. We give particular attention to the design of identification experiments and to online reconstruction of state coordinates, as these strongly influence the quality of the estimation process. The importance of correct friction modeling and the estimation of friction parameters are illuminated. The models of robot kinematics and dynamics can be used in model-based nonlinear control. The remaining dynamics cannot be ignored if high-performance robot operation with adequate robustness is required. The complete procedure is demonstrated for a direct-drive robotic arm with three rotational joints.

show abstract

Section: B Model Verification With a Writing Taskmentioning

confidence: 79%

“…The handwriting in robotics was presented in [40], [41]. Surveys of related research results are available in [42] and [43], also presenting the sequence of letters we use for model validation.…”

Section: ) Friction Modeling and Estimationmentioning

confidence: 99%

Modeling and Identification for High-Performance Robot Control: An RRR-Robotic Arm Case Study

Kostic

Jager

Steinbuch

et al. 2004

IEEE Trans. Contr. Syst. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…To evaluate if the estimates provide a close match between the model (1) and the real robot dynamics for all three loads, validation experiments have been conducted. In these experiments, the RRR-robot performed a writing task, suggested in [29], and depicted in Fig. 6.…”

Section: ) Parameter Estimation Resultsmentioning

confidence: 99%

“…From Fig. 10, it can be seen that the actual -filter matches the inverse of the process sensitivities until approximately 20 [ In order to preserve the convergence criterion (29) in the frequency ranges where the -filter mismatches the inverse of the process sensitivities, the robustness filter is used, as explained in Section V. This filter is chosen to be a fourth-order low-pass digital Butterworth filter with a passband magnitude equal to one. The cutoff frequency of the -filter can never exceed the frequency up to which the -filter is a good representation of the inverse of the process sensitivity model.…”

Section: B Ilc Resultsmentioning

confidence: 99%

“…Substitution of (24) and (25) into (26), results in (28) If the second term on the right-hand side of (28) is negligible, then the condition for the amplitude of the error in trial to be smaller than the amplitude of the error in trial , is given by (29) with denoting the infinity norm. The inequality (29) is known as the condition for error convergence toward zero.…”

Section: Ilcmentioning

confidence: 99%

See 1 more Smart Citation

Learning-based identification and iterative learning control of direct-drive robots

Bukkems

Kostic²,

Jager

et al. 2005

IEEE Trans. Contr. Syst. Technol.

Self Cite

View full text Add to dashboard Cite

A combination of model-based and iterative learning control (ILC) is proposed as a method to achieve high-quality motion control of direct-drive robots in repetitive motion tasks. We include both model-based and learning components in the total control law, as their individual properties influence the performance of motion control. The model-based part of the controller compensates much of the nonlinear and coupled robot dynamics. A new procedure for estimating the parameters of the rigid body model, implemented in this part of the controller, is used. This procedure is based on a batch-adaptive control algorithm that estimates the model parameters online. Information about the dynamics not covered by the rigid body model, due to flexibilities, is acquired experimentally, by identification. The models of the flexibilities are used in the design of the iterative learning controllers for the individual joints. Use of the models facilitates quantitative prediction of performance improvement via ILC. The effectiveness of the combination of the model-based and the iterative learning controllers is demonstrated in experiments on a spatial serial direct-drive robot with revolute joints.

show abstract

Generation of natural motions for redundant multi‐joint systems: A differential‐geometric approach based upon the principle of least actions

et al. 2005

View full text Add to dashboard Cite

This article challenges Bernstein's problem of redundant degrees of freedom (DOF) that remains unsolved from both the standpoints of physiology and robotics. A rather simpler but difficult control problem of movements of human‐like multi‐joint reaching with excess DOF is analyzed from Newtonian mechanics and differential geometry. It is shown that, regardless of ill‐posedness of inverse kinematics for such a redundant system, a simpler control signal composed of a well‐tuned (synergistic) combination of task‐space position feedback (corresponding to spring‐like forces) and joint velocity feedback (viscous‐like forces) leads to a skilled motion of reaching in a natural way without solving inverse kinematics or dynamics. Fundamental characteristics of human skilled multi‐joint movements such as (1) generation of a quasi‐straight line trajectory of the endpoint and (2) a little “variability” in task space but notable “variability” in joint space are analyzed from the concepts of “stability on an EP (equilibrium‐point) manifold” and “transferability to an EP submanifold.” It is claimed that the control signal exerts torques on joints of the whole arm just like a single virtual‐spring drawing the endpoint of the arm to the target while giving a specified viscosity to each joint. This leads to an interpretation that skilled reaching movements emerge through formation of a set of neuro‐motor signals exerting relevant group of muscles to generate a total potential energy equivalent to that of the spring. Discussions are presented on how such control signals in case of human reaching can be generated in a feedforward manner with capability of anticipatory adjustments of stiffness. © 2005 Wiley Periodicals, Inc.

show abstract

Illustrating man-machine motion analogy in robotics - The handwriting problem

Cited by 25 publications

References 37 publications

Modeling and Identification for High-Performance Robot Control: An RRR-Robotic Arm Case Study

Modeling and Identification for High-Performance Robot Control: An RRR-Robotic Arm Case Study

Learning-based identification and iterative learning control of direct-drive robots

Generation of natural motions for redundant multi‐joint systems: A differential‐geometric approach based upon the principle of least actions

Contact Info

Product

Resources

About