| 1. |
- Gunnarsson, Svante, et al.
(författare)
-
A Model Based Iterative Learning Control Method Applied to an Industrial Robot
- 1999
-
Ingår i: Proceedings of the Second Conference on Computer Science and Systems Engineering. - Linköping : Linköping University Electronic Press.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A synthesis algorithm for the filters in a first order ILC is presented and applied on an industrial robot. The proposed ILC synthesis method is evaluated using two experiments on the robot. The first is a one-axis experiment where the system can be seen as a single servo. A modeling experiment is done to give input to the synthesis algorithm and then ILC is applied to the single axis showing a dramatic improvement in trajectory following. In the second experiment ILC is applied to a more complex multi axes motion where the robot draws a circle in a plane. The evaluation of the result is done using a pen mounted on the robot and it is evident that also on the arm-side an improved motion can be achieved. In both experiments the error converges to a stable level in about 5 iterations. Since a model is desired for the synthesis, an extra iteration has to be done for the modeling experiment. In this particular case a good path following can therefore be achieved after 6 iterations.
|
|
| 2. |
- Gunnarsson, Svante, et al.
(författare)
-
A Short Introduction to Iterative Learning Control
- 1997
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An introduction to Iterative Learning Control (ILC) is given. The basic principle behind ILC in both open loop and closed loop problems is explained. A general class of algorithms for updating of the ILC input signal is presented and the choice of the filters in the update algortihm is discussed with respect to convergence, robustness and disturbance sensitivity.
|
|
| 3. |
- Gunnarsson, Svante, 1959-, et al.
(författare)
-
On the Use of Learning Control for Improved Performance in Robot Control Systems
- 1997
-
Ingår i: Proceedings of the 1997 European Control Conference. - Linköping : Linköping University Electronic Press.
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Iterative learning control applied to a simplified model of a robot arm is studied. The iterative learning control input signal is used in combination with conventional feed-back and feed-forward control, and the aim is to let the learning control signal handle the effects of unmodeled dynamics and friction. Convergence and robustness aspects of the choice of filters in the updating scheme of the iterative learning control signal are studied.
|
|
| 4. |
- Gunnarsson, Svante, et al.
(författare)
-
Some Aspects of an Optimization Approach to Iterative Learning Control
- 1999
-
Ingår i: Proceedings of the 38th IEEE Conference on Decision and Control. - Linköping : Linköping University Electronic Press. - 0780352505 ; , s. 1581-1586 vol.2
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- An optimization approach to Iterative Learning Control (ILC) is considered. The ILC algorithm is formed by minimizing a quadratic criterion in the control error and input signal. A frequency domain interpretation of the derived updating algorithm is given. Experiments carried out on an ABB IRB 1400 are presented.
|
|
| 5. |
- Gunnarsson, Svante, 1959-, et al.
(författare)
-
Some Experiences of the use of Iterative Learning Control for Performance Improvement in Robot Control Systems
- 1997
-
Ingår i: Proceedings of the 5th IFAC Symposium on Robot Control. - Linköping : Linköping University Electronic Press. - 0080430260 ; , s. 379-
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Some aspects of the use of learning control for improved performance in robot control systems are studied. The learning control signal is used in combination with conventional feed-back and feed-forward control. The effects of disturbances, unmodeled dynamics and friction are studied theoretically and in simulations of a simplified model of a robot arm. Convergence and robustness aspects of the choice of filters in the updating scheme of the learning control signal are studied.
|
|
| 6. |
- Norrlöf, Mikael, 1971-, et al.
(författare)
-
A Frequency Domain Analysis of a Second Order Iterative Learning Control Algorithm
- 1999
-
Ingår i: Proceedings of the 38th IEEE Conference on Decision and Control. - Linköping : Linköping University Electronic Press. - 0780352505 ; , s. 1587-1592 vol.2
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A frequency domain analysis method of a second order iterative learning control (ILC) algorithm is considered. Using the notion of iterative systems bounds for stability are presented in the frequency domain for the second order term. The bounds are found using a geometrical approach based on the special structure of the transfer matrix in the iterative system. Two examples are included showing how the analysis method can be used in an application.
|
|
| 7. |
- Norrlöf, Mikael, 1971-
(författare)
-
On Analysis and Implementation of Iterative Learning Control
- 1998
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many of the control systems used in factory production today are programmed to perform the same task repeatedly. In particular this is the case for industrial robots where the same motion is performed every time the same program is executed. An interesting observation, for the industrial robot, is that the error in the different iterations of the same exercise is highly repetitive.In the thesis Iterative Learning Control is applied to an industrial robot control system from ABB. Using Iterative Learning Control the tracking error on the motor side has been reduced without changing the internal structure or any parameters in the robot controller. The results from the experiments show that Iterative Learning Control can be used to successfully reduce the tracking error in an industrial robot control system.The implementation of the functions needed in the robot controller is described. By using a combination of already present functions in the system and software development the Iterative Learning Control method has been successfully applied to the commercial robot controller, S4C.The Iterative Learning Control method uses knowledge from previous exercises to improve the control in future executions of the same exercise. For the robot control case, this means remembering the error that was achieved in the previous iteration of the exercise and to change the input signal to the system based on this knowledge.A theory including analysis and synthesis for Iterative Learning Controlis provided, and a starting point for a more general theory on iterativesystems is given. A general discussion on how the Iterative Learning Control method can deal with repetitive and random disturbances is also included.Two of the given design algorithms are evaluated by experiments. The experiments show that the methods apply very well to the control of the ABB robot. The error reaches steady state levels, in fact the quantization level, already after 3 iterations with a model based synthesis approach.
|
|
| 8. |
- Norrlöf, Mikael, 1971-, et al.
(författare)
-
On Iterative Learning Control with Disturbances
- 1998
-
Ingår i: Proceedings of Reglermöte 98. ; , s. 198-202
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Iterative Learning Control is presented briefly together with some results on convergence and some new results on iterative learning control with measurement disturbances. In the example given, iterative learning control is used in combination with conventional feed-back and feed-forward control, and it is shown that the control is highly affected by the disturbances. Some ideas on how the filters in the algorithm should be chosen are also discussed.
|
|
| 9. |
- Norrlöf, Mikael, 1971-, et al.
(författare)
-
Some Results on Iterative Learning Control with Disturbances
- 1998
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Iterative Learning Control is presented briefly together with a review of some results on convergence and some new results on Iterative Learning Control with load disturbances and measurement disturbances. In the example presented, Iterative Learning Control is used in combination with conventional feed-back and feed-forward control, and it is shown that learning control is highly affected by the different disturbances. Some ideas on how the filters in the ILC algorithm should be chosen are also discussed.
|
|
| 10. |
- Norrlöf, Mikael, 1971-, et al.
(författare)
-
Using Iterative Learning Control to get Better Performance of Robot Control Systems
- 1997
-
Ingår i: Proceedings of Robotikdagarna 1997. - Linköping : Linköping University Electronic Press.
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Many manipulators at work in factories today repeat their motions over and over in cycles and if there are errors in following the trajectory these errors will also be repeated cycle after cycle. The basic idea behind iterative learning control (ILC) is that the controller should learn from previous cycles and perform better every cycle. Iterative learning control is used in combination with conventional feed-back and feed-forward control, and it is shown that learning control signal can handle the effects of unmodeled dynamics and friction. Convergence and disturbance effects as well as the choice of filters in the updating scheme are also addressed.
|
|
