{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/14700"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/14700","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"The internal performance of iterative feedback tuning","abstract":"Under certain conditions Iterative Feedback Tuning (IFT) may produce a controller that cancels the poles of the process and as a result can give a closed loop that has poor internal performance. The disadvantage of this is that the closed loop will have poor input disturbance rejection. A solution for ensuring that IFT does not have poor internal performance is to make sure that the disturbance rejection is adequate. However an adequate input disturbance may lead to other undesirable dynamics in the closed loop performance. These are such as overshoot in the response for setpoint tracking and that for output disturbance rejection. On the other hand the advantage of pole shifting is that for a one degree of freedom control structure all the characteristic equations of the loop transfer functions will be the same. Four methods are proposed for avoiding pole-zero cancellation by concentrating on the input disturbance. These methods are using: a model for input disturbance rejection, time-weighted IFT for disturbance rejection, a setpoint-tracking model with overshoot and approximate pole placement IFT. Approximate pole placement IFT was chosen as the best method. The reason is that the dynamics of the closed loop can be specified with the choice of characteristic equation. This method was then investigated further to establish its feasibility on a physical system. After the evaluation of this method, it was applied on a DC motor for speed control to show that is viable in practice. Multiple experiments were done to show that this method does not produce a controller that cancels the process poles, confirming it as a good solution to prevent poor internal performance.","abstract_html":"Under certain conditions Iterative Feedback Tuning (IFT) may produce a controller that cancels the poles of the process and as a result can give a closed loop that has poor internal performance. The disadvantage of this is that the closed loop will have poor input disturbance rejection. A solution for ensuring that IFT does not have poor internal performance is to make sure that the disturbance rejection is adequate. However an adequate input disturbance may lead to other undesirable dynamics in the closed loop performance. These are such as overshoot in the response for setpoint tracking and that for output disturbance rejection. On the other hand the advantage of pole shifting is that for a one degree of freedom control structure all the characteristic equations of the loop transfer functions will be the same. Four methods are proposed for avoiding pole-zero cancellation by concentrating on the input disturbance. These methods are using: a model for input disturbance rejection, time-weighted IFT for disturbance rejection, a setpoint-tracking model with overshoot and approximate pole placement IFT. Approximate pole placement IFT was chosen as the best method. The reason is that the dynamics of the closed loop can be specified with the choice of characteristic equation. This method was then investigated further to establish its feasibility on a physical system. After the evaluation of this method, it was applied on a DC motor for speed control to show that is viable in practice. Multiple experiments were done to show that this method does not produce a controller that cancels the process poles, confirming it as a good solution to prevent poor internal performance.","abstract_has_math":false,"creators":["Sikaundi, Jaston"],"institution":"Department of Electrical Engineering","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Braae, Martin"],"committee_chairs":[],"committee_members":[],"year":2008,"date_issued":"2008","date_published":"2008","updated_at":"2026-07-22T22:23:45Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/14700","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Braae, Martin"]},{"key":"dc:creator","label":"Author","values":["Sikaundi, Jaston"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-11-08T04:44:22Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-11-08T04:44:22Z"]},{"key":"dc:date.issued","label":"Date","values":["2008"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Electrical Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Master Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Masters"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["MSc"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/14700"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliographical references (p. 113-115)."]},{"key":"dc:description.abstract","label":"Abstract","values":["Under certain conditions Iterative Feedback Tuning (IFT) may produce a controller that cancels the poles of the process and as a result can give a closed loop that has poor internal performance. The disadvantage of this is that the closed loop will have poor input disturbance rejection. A solution for ensuring that IFT does not have poor internal performance is to make sure that the disturbance rejection is adequate. However an adequate input disturbance may lead to other undesirable dynamics in the closed loop performance. These are such as overshoot in the response for setpoint tracking and that for output disturbance rejection. On the other hand the advantage of pole shifting is that for a one degree of freedom control structure all the characteristic equations of the loop transfer functions will be the same. Four methods are proposed for avoiding pole-zero cancellation by concentrating on the input disturbance. These methods are using: a model for input disturbance rejection, time-weighted IFT for disturbance rejection, a setpoint-tracking model with overshoot and approximate pole placement IFT. Approximate pole placement IFT was chosen as the best method. The reason is that the dynamics of the closed loop can be specified with the choice of characteristic equation. This method was then investigated further to establish its feasibility on a physical system. After the evaluation of this method, it was applied on a DC motor for speed control to show that is viable in practice. Multiple experiments were done to show that this method does not produce a controller that cancels the process poles, confirming it as a good solution to prevent poor internal performance."]},{"key":"dc:title","label":"Title","values":["The internal performance of iterative feedback tuning"]}]}],"canonical_facts":{"dc:contributor.advisor":["Braae, Martin"],"dc:creator":["Sikaundi, Jaston"],"dc:date.accessioned":["2015-11-08T04:44:22Z"],"dc:date.available":["2015-11-08T04:44:22Z"],"dc:date.issued":["2008"],"dc:description":["Includes bibliographical references (p. 113-115)."],"dc:description.abstract":["Under certain conditions Iterative Feedback Tuning (IFT) may produce a controller that cancels the poles of the process and as a result can give a closed loop that has poor internal performance. The disadvantage of this is that the closed loop will have poor input disturbance rejection. A solution for ensuring that IFT does not have poor internal performance is to make sure that the disturbance rejection is adequate. However an adequate input disturbance may lead to other undesirable dynamics in the closed loop performance. These are such as overshoot in the response for setpoint tracking and that for output disturbance rejection. On the other hand the advantage of pole shifting is that for a one degree of freedom control structure all the characteristic equations of the loop transfer functions will be the same. Four methods are proposed for avoiding pole-zero cancellation by concentrating on the input disturbance. These methods are using: a model for input disturbance rejection, time-weighted IFT for disturbance rejection, a setpoint-tracking model with overshoot and approximate pole placement IFT. Approximate pole placement IFT was chosen as the best method. The reason is that the dynamics of the closed loop can be specified with the choice of characteristic equation. This method was then investigated further to establish its feasibility on a physical system. After the evaluation of this method, it was applied on a DC motor for speed control to show that is viable in practice. Multiple experiments were done to show that this method does not produce a controller that cancels the process poles, confirming it as a good solution to prevent poor internal performance."],"dc:identifier.uri":["http://hdl.handle.net/11427/14700"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Electrical Engineering"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["The internal performance of iterative feedback tuning"],"dc:type":["Master Thesis"],"dc:type.qualificationlevel":["Masters"],"dc:type.qualificationname":["MSc"]},"updated_at":"2026-07-22T22:23:45Z"}