Differential GPS operation (DGPS) uses a reference station at a known location to calculate and broadcast pseudorange corrections to local users, resulting in improved user position accuracy. DGPS accuracy is limited by the ability of the reference station to remove the effects of receiver measurement noise and multipath errors from the broadcast corrections. The article presents two new algorithms for DGPS reference station design. The article also presents an experimental analysis of the accuracy of the algorithms. The single and two frequency reference station algorithms, respectively, achieve 6 dB and >20 dB improvement relative to the raw corrections.
{"title":"Experimental differential GPS reference station evaluation","authors":"J. Farrell, T. Givargis","doi":"10.1109/ACC.1999.782446","DOIUrl":"https://doi.org/10.1109/ACC.1999.782446","url":null,"abstract":"Differential GPS operation (DGPS) uses a reference station at a known location to calculate and broadcast pseudorange corrections to local users, resulting in improved user position accuracy. DGPS accuracy is limited by the ability of the reference station to remove the effects of receiver measurement noise and multipath errors from the broadcast corrections. The article presents two new algorithms for DGPS reference station design. The article also presents an experimental analysis of the accuracy of the algorithms. The single and two frequency reference station algorithms, respectively, achieve 6 dB and >20 dB improvement relative to the raw corrections.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"295 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122735853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents sliding mode as viewed from control engineering practice. It catalogues implementable sliding mode control design solutions, and provides a tutorial for control engineers who are interested in applying sliding mode.
{"title":"Sliding mode: control engineering in practice","authors":"K. Young, U. Ozguner","doi":"10.1109/ACC.1999.782758","DOIUrl":"https://doi.org/10.1109/ACC.1999.782758","url":null,"abstract":"This paper presents sliding mode as viewed from control engineering practice. It catalogues implementable sliding mode control design solutions, and provides a tutorial for control engineers who are interested in applying sliding mode.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"412 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122790043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Summary form only given. In many processes, especially distillation columns, feed composition changes can be a source of large disturbances that affect process operations. Feed composition changes affect the physical behavior of the process phenomenon, i.e., thermodynamics, vapor-liquid equilibrium, etc., and therefore, such disturbances tend to have a more pronounced impact on the operations, and typically, it takes more time to recover from such upsets. Often times, feed composition changes are not transient disturbances. They can be the result of changes made "on-purpose" to the front-end of the unit such as adjustments to reactor conditions, etc. Moreover, there is usually a significant deadtime associated with such disturbances. All of the above can pose a challenging control problem. The column operation can be adversely affected if the feed composition change is not anticipated properly and appropriate corrective action are not taken in a timely manner. The problem is complicated by the fact that online analyzers are rare in industrial practice partly due to analyzer reliability and maintenance issues, and partly due to the fact that online analysis of certain streams are difficult or cost prohibitive.
{"title":"Control of a distillation column using virtual analyzer","authors":"S. Ramchandran","doi":"10.1109/ACC.1999.782337","DOIUrl":"https://doi.org/10.1109/ACC.1999.782337","url":null,"abstract":"Summary form only given. In many processes, especially distillation columns, feed composition changes can be a source of large disturbances that affect process operations. Feed composition changes affect the physical behavior of the process phenomenon, i.e., thermodynamics, vapor-liquid equilibrium, etc., and therefore, such disturbances tend to have a more pronounced impact on the operations, and typically, it takes more time to recover from such upsets. Often times, feed composition changes are not transient disturbances. They can be the result of changes made \"on-purpose\" to the front-end of the unit such as adjustments to reactor conditions, etc. Moreover, there is usually a significant deadtime associated with such disturbances. All of the above can pose a challenging control problem. The column operation can be adversely affected if the feed composition change is not anticipated properly and appropriate corrective action are not taken in a timely manner. The problem is complicated by the fact that online analyzers are rare in industrial practice partly due to analyzer reliability and maintenance issues, and partly due to the fact that online analysis of certain streams are difficult or cost prohibitive.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122833422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An optical disk drive has an excellent advantage of random accessibility. However, increased rotational velocity of a disk and limitations of mechanical structure have hindered implementation of direct seek control despite its effectiveness in reducing access time. A two-stage seek operation is instead adopted in conventional optical disk drives. In this case, fine seek control is restricted in its applicable range by the risk of misalignment between objective lens and laser beam axis, which causes the access time to increase enormously. In the paper, a control algorithm for extending the applicable range of fine seek is proposed with an appropriate control structure. The conventional fine seek technique utilized only a fine actuator without any maneuvering of a coarse actuator. With assistance of the coarse actuator, however, the misalignment of objective lens is compensated and the range of fine seek is extended in result. The proposed algorithm is applied to an optical disk drive to show its feasibility and some results are presented.
{"title":"New fine seek control for optical disk drives","authors":"J. Ryoo, K. Jin, Tae-Yong Doh, M. Chung","doi":"10.1109/ACC.1999.782444","DOIUrl":"https://doi.org/10.1109/ACC.1999.782444","url":null,"abstract":"An optical disk drive has an excellent advantage of random accessibility. However, increased rotational velocity of a disk and limitations of mechanical structure have hindered implementation of direct seek control despite its effectiveness in reducing access time. A two-stage seek operation is instead adopted in conventional optical disk drives. In this case, fine seek control is restricted in its applicable range by the risk of misalignment between objective lens and laser beam axis, which causes the access time to increase enormously. In the paper, a control algorithm for extending the applicable range of fine seek is proposed with an appropriate control structure. The conventional fine seek technique utilized only a fine actuator without any maneuvering of a coarse actuator. With assistance of the coarse actuator, however, the misalignment of objective lens is compensated and the range of fine seek is extended in result. The proposed algorithm is applied to an optical disk drive to show its feasibility and some results are presented.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129878662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A real-time monitoring and control strategy is presented for a continuous polyester plant. This process consists of three reaction steps, namely, esterification, prepolymerization, and finishing polymerization. This paper is focused on the prepolymerization reactor. A high-fidelity dynamic model that is efficient and accurate for real-time monitoring and control is developed. As this study is focused on real-time monitoring and control applications, the model development, configuration, and implementation are performed using a real-time dynamic simulation software, SimSuite Pro/sup TM/, running in tandem with the plant distributed control system, a D/3 DCS/sup TM/. By using this model, a multirate control strategy is developed for polyester molecular weight and carboxyl acid concentration control. In addition to the fast measurements, i.e. temperature and pressure, this controller also utilizes slow measurements, i.e. molecular weight and acid concentration. In the absence of slow measurements, the estimates from the dynamic model are used.
{"title":"Monitoring and control of polyester production process","authors":"S. Valluri, G. Lei, C. Porter","doi":"10.1109/ACC.1999.783218","DOIUrl":"https://doi.org/10.1109/ACC.1999.783218","url":null,"abstract":"A real-time monitoring and control strategy is presented for a continuous polyester plant. This process consists of three reaction steps, namely, esterification, prepolymerization, and finishing polymerization. This paper is focused on the prepolymerization reactor. A high-fidelity dynamic model that is efficient and accurate for real-time monitoring and control is developed. As this study is focused on real-time monitoring and control applications, the model development, configuration, and implementation are performed using a real-time dynamic simulation software, SimSuite Pro/sup TM/, running in tandem with the plant distributed control system, a D/3 DCS/sup TM/. By using this model, a multirate control strategy is developed for polyester molecular weight and carboxyl acid concentration control. In addition to the fast measurements, i.e. temperature and pressure, this controller also utilizes slow measurements, i.e. molecular weight and acid concentration. In the absence of slow measurements, the estimates from the dynamic model are used.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130281815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Functional electrical stimulation (FES) can be used for restoring of the standing and walking of humans with spinal cord injury. Existing control algorithms typically use a dynamic model of the human body and methods of analytic mechanics. Available models do not take into account the characteristics of the segmented spinal column, upper body, neck and the head, arm support over crutches or walker, and substantial changes of the neuro-musculo-skeletal characteristics caused by the injury; hence, control does not work well enough. The alternative method for controlling bipedal walking is cloning of a walking pattern of an able-bodied subject. Walking with a constant speed, over even terrain, with no or small perturbations is a cyclic activity, which can be considered as a finite automaton. The automaton includes sensory inputs and motor (muscle) outputs. The method of cloning of this automaton includes two phases: 1) simulation of a customized biomechanical model of a potential user walking with a pattern of an able-bodied subject; 2) determining the mapping by a radial basis function neural network between the input (trajectory) and outputs (simulated muscle activation).
{"title":"Control of bipedal locomotion assisted with functional electrical stimulation","authors":"D. Popović, S. Joni","doi":"10.1109/ACC.1999.783565","DOIUrl":"https://doi.org/10.1109/ACC.1999.783565","url":null,"abstract":"Functional electrical stimulation (FES) can be used for restoring of the standing and walking of humans with spinal cord injury. Existing control algorithms typically use a dynamic model of the human body and methods of analytic mechanics. Available models do not take into account the characteristics of the segmented spinal column, upper body, neck and the head, arm support over crutches or walker, and substantial changes of the neuro-musculo-skeletal characteristics caused by the injury; hence, control does not work well enough. The alternative method for controlling bipedal walking is cloning of a walking pattern of an able-bodied subject. Walking with a constant speed, over even terrain, with no or small perturbations is a cyclic activity, which can be considered as a finite automaton. The automaton includes sensory inputs and motor (muscle) outputs. The method of cloning of this automaton includes two phases: 1) simulation of a customized biomechanical model of a potential user walking with a pattern of an able-bodied subject; 2) determining the mapping by a radial basis function neural network between the input (trajectory) and outputs (simulated muscle activation).","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130598307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brown, Gonye and Schwaber (1998) presented a modified PI controller that attempted to improve performance of the closed loop system by only applying the integral action intermittently. This enabled the control actions to be tuned more aggressively, thus improving the disturbance rejection capabilities of the controller. This approach has now been generalized to handle other predictable disturbances, called the intermittent control. The controller begins as a traditional feedback controller designed to cancel random disturbances. Additional filters operate in parallel with this feedback controller and attempt to detect predictable disturbances. When these predictable disturbances are identified, an additional feedback loop is invoked. This additional parallel feedback loop is designed to specifically cancel the identified disturbance. When the disturbance appears to be cancelled, the feedback loop is opened creating an open-loop controller.
{"title":"Intermittent cancellation control: a control paradigm inspired by mammalian blood pressure control","authors":"L. J. Brown, J. Schwaber","doi":"10.1109/ACC.1999.782756","DOIUrl":"https://doi.org/10.1109/ACC.1999.782756","url":null,"abstract":"Brown, Gonye and Schwaber (1998) presented a modified PI controller that attempted to improve performance of the closed loop system by only applying the integral action intermittently. This enabled the control actions to be tuned more aggressively, thus improving the disturbance rejection capabilities of the controller. This approach has now been generalized to handle other predictable disturbances, called the intermittent control. The controller begins as a traditional feedback controller designed to cancel random disturbances. Additional filters operate in parallel with this feedback controller and attempt to detect predictable disturbances. When these predictable disturbances are identified, an additional feedback loop is invoked. This additional parallel feedback loop is designed to specifically cancel the identified disturbance. When the disturbance appears to be cancelled, the feedback loop is opened creating an open-loop controller.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130655317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Focuses on the specific issue of machinery health and availability of individual power generating units on a power distribution grid while emphasizing the automatic load dispatch and control in electric power distribution systems. This concept of life extending control and health management is incorporated into the decision-making process of a remotely located control center. The goal is to improve efficiency and availability of the entire grid. Fuzzy logic is used to realize an availability-improving controller for load dispatch.
{"title":"Simulation of a load dispatch control system","authors":"P. Kallappa, A. Ray, S. Phoha","doi":"10.1109/ACC.1999.786139","DOIUrl":"https://doi.org/10.1109/ACC.1999.786139","url":null,"abstract":"Focuses on the specific issue of machinery health and availability of individual power generating units on a power distribution grid while emphasizing the automatic load dispatch and control in electric power distribution systems. This concept of life extending control and health management is incorporated into the decision-making process of a remotely located control center. The goal is to improve efficiency and availability of the entire grid. Fuzzy logic is used to realize an availability-improving controller for load dispatch.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123847338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Describes an approach for the use of the piezoelectric material of PZT to damp structural vibrations of a high speed manufacturing equipment controlled by PD position feedback. Applying a control voltage to a PZT actuator bonded to the surface of the structure, the actuator generates a shear force that opposes the structural deformation. The unique feature of the actuator control here is that the command voltage employs a linear velocity feedback for easy practical implementation. To examine the actuator placement, a new method is proposed based on the modes shape functions. Simulation results confirm these theoretical predictions.
{"title":"PZT actuator placement for structural vibration damping of high speed manufacturing equipment","authors":"Dong Sun, J. Mills","doi":"10.1109/ACC.1999.783212","DOIUrl":"https://doi.org/10.1109/ACC.1999.783212","url":null,"abstract":"Describes an approach for the use of the piezoelectric material of PZT to damp structural vibrations of a high speed manufacturing equipment controlled by PD position feedback. Applying a control voltage to a PZT actuator bonded to the surface of the structure, the actuator generates a shear force that opposes the structural deformation. The unique feature of the actuator control here is that the command voltage employs a linear velocity feedback for easy practical implementation. To examine the actuator placement, a new method is proposed based on the modes shape functions. Simulation results confirm these theoretical predictions.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123499592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The objective of the paper is to outline the limitations of classical PID controllers acting on the error signal for control of a plant modelled as a linear transfer function. It is shown how a modified form of controller, a PI-PD controller, which corresponds to PI control of a plant transfer function changed by the PD feedback can produce improved control in several situations. This implementation avoids the derivative kick problem associated with derivative action in the forward path, which still exists when a filter is included. Further, the PD in the inner feedback loop enables placement of the open loop poles in appropriate positions thereby providing good control for open loop system transfer functions having resonances, unstable, or integrating poles. The simulation results show significantly improved performance of the proposed control method particularly for the latter processes.
{"title":"Limitations of PID controllers","authors":"D. Atherton, S. Majhi","doi":"10.1109/ACC.1999.786236","DOIUrl":"https://doi.org/10.1109/ACC.1999.786236","url":null,"abstract":"The objective of the paper is to outline the limitations of classical PID controllers acting on the error signal for control of a plant modelled as a linear transfer function. It is shown how a modified form of controller, a PI-PD controller, which corresponds to PI control of a plant transfer function changed by the PD feedback can produce improved control in several situations. This implementation avoids the derivative kick problem associated with derivative action in the forward path, which still exists when a filter is included. Further, the PD in the inner feedback loop enables placement of the open loop poles in appropriate positions thereby providing good control for open loop system transfer functions having resonances, unstable, or integrating poles. The simulation results show significantly improved performance of the proposed control method particularly for the latter processes.","PeriodicalId":441363,"journal":{"name":"Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124124332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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