Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138135
J. King, R. D. Irwin
An H/sup infinity / controller is designed for a subsystem of a large, flexible space structure. Issues concerning the incorporation of robustness and performance criteria as frequency-dependent weights are addressed. Simulation results and closed-loop frequency responses are included. In addition, an analysis of the singular-value frequency response of the controller raises questions regarding the robustness of H/sup infinity / designs when faced with uncertainty in plant modal frequencies.<>
{"title":"Issues in the application of H/sup infinity / control to large space structures","authors":"J. King, R. D. Irwin","doi":"10.1109/SSST.1990.138135","DOIUrl":"https://doi.org/10.1109/SSST.1990.138135","url":null,"abstract":"An H/sup infinity / controller is designed for a subsystem of a large, flexible space structure. Issues concerning the incorporation of robustness and performance criteria as frequency-dependent weights are addressed. Simulation results and closed-loop frequency responses are included. In addition, an analysis of the singular-value frequency response of the controller raises questions regarding the robustness of H/sup infinity / designs when faced with uncertainty in plant modal frequencies.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133105435","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138224
E.A. Grissom, P. Rajan
The authors present an algorithm for the implementation of the two-dimensional discrete cosine transform (DCT) for 2/sup n/*2/sup n/ data points. This algorithm is based on a recently published fast one-dimensional DCT algorithm. The new algorithm is recursive, fast, and numerically stable. The two-dimensional decomposition in this new algorithm is based on the vector-radix approach. In this approach, the data matrix is partitioned into four subblocks, each of which, after some processing is transformed by a lower order DCT. The results from the lower order transforms are then combined to form the desired two-dimensional DCT. The overall complexity of the new transform is compared in terms of the number of multiplications and additions required to perform the two-dimensional DCT with those of a row/column implementation using the fast one-dimensional transform.<>
{"title":"An algorithm for a fast two-dimensional discrete cosine transform","authors":"E.A. Grissom, P. Rajan","doi":"10.1109/SSST.1990.138224","DOIUrl":"https://doi.org/10.1109/SSST.1990.138224","url":null,"abstract":"The authors present an algorithm for the implementation of the two-dimensional discrete cosine transform (DCT) for 2/sup n/*2/sup n/ data points. This algorithm is based on a recently published fast one-dimensional DCT algorithm. The new algorithm is recursive, fast, and numerically stable. The two-dimensional decomposition in this new algorithm is based on the vector-radix approach. In this approach, the data matrix is partitioned into four subblocks, each of which, after some processing is transformed by a lower order DCT. The results from the lower order transforms are then combined to form the desired two-dimensional DCT. The overall complexity of the new transform is compared in terms of the number of multiplications and additions required to perform the two-dimensional DCT with those of a row/column implementation using the fast one-dimensional transform.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115364065","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138161
R. Haggard, C. Alford
A parallel processing system consisting of an array of commercial microprocessors known as transputers is utilized to solve the Navier Stokes partial differential equations for incompressible laminar flow. Two parallel algorithms are given for the solution of these equations. The structure and organization of the system hardware is described, and a method is presented for mapping the problem domain onto the processor array. The performance of the two algorithms is analyzed for a wide range of system configurations and grid sizes, showing the limitations of this system.<>
{"title":"Computational fluid dynamics on the transputer: system organization and performance","authors":"R. Haggard, C. Alford","doi":"10.1109/SSST.1990.138161","DOIUrl":"https://doi.org/10.1109/SSST.1990.138161","url":null,"abstract":"A parallel processing system consisting of an array of commercial microprocessors known as transputers is utilized to solve the Navier Stokes partial differential equations for incompressible laminar flow. Two parallel algorithms are given for the solution of these equations. The structure and organization of the system hardware is described, and a method is presented for mapping the problem domain onto the processor array. The performance of the two algorithms is analyzed for a wide range of system configurations and grid sizes, showing the limitations of this system.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116037421","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138193
A. Bose, A. Cover, J. Reneke
Sufficient conditions are developed for three-dimensional quadratic systems with conservative nonlinearities to be point dissipative. The conditions are motivated geometrically. Lorenz systems are shown to fall within the class of systems studied.<>
{"title":"On three dimensional point dissipative systems of differential equations with quadratic nonlinearity","authors":"A. Bose, A. Cover, J. Reneke","doi":"10.1109/SSST.1990.138193","DOIUrl":"https://doi.org/10.1109/SSST.1990.138193","url":null,"abstract":"Sufficient conditions are developed for three-dimensional quadratic systems with conservative nonlinearities to be point dissipative. The conditions are motivated geometrically. Lorenz systems are shown to fall within the class of systems studied.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132023057","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138194
A. Smiarowski, J.N. Anderson
The temporal distribution of input and output is the main feature of distributed sampling control (DSC). The DSC method was first used to improve the performance of multi-input-multioutput (MIMO) robotic control systems. Control algorithms to which this method can be applied require each system output (or state variable) at a different time point and generate each plant input at a different time point. The underlying concept is introduced, and its performance is demonstrated through examples of simple robots operating with model-based controllers. Two controllers are used to drive the same plants. One is based on conventional control principles where feedback signals are simultaneously sampled and plant inputs are applied simultaneously, and the other utilizes DSC. Differences in the control action are then analyzed. General aspects of the distributed sampling controls are also discussed.<>
{"title":"Input/output distribution in digital control","authors":"A. Smiarowski, J.N. Anderson","doi":"10.1109/SSST.1990.138194","DOIUrl":"https://doi.org/10.1109/SSST.1990.138194","url":null,"abstract":"The temporal distribution of input and output is the main feature of distributed sampling control (DSC). The DSC method was first used to improve the performance of multi-input-multioutput (MIMO) robotic control systems. Control algorithms to which this method can be applied require each system output (or state variable) at a different time point and generate each plant input at a different time point. The underlying concept is introduced, and its performance is demonstrated through examples of simple robots operating with model-based controllers. Two controllers are used to drive the same plants. One is based on conventional control principles where feedback signals are simultaneously sampled and plant inputs are applied simultaneously, and the other utilizes DSC. Differences in the control action are then analyzed. General aspects of the distributed sampling controls are also discussed.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123373021","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138164
N. Alvertos
A stereo camera arrangement that results from combining the lateral model with the axial motion model provides three views of a scene to be utilized in a stereo correspondence algorithm. The third view of the scene serves as a verification of established correspondences between the other two. Only the correspondence of edge points is considered. Some geometrical relations underlying each model and their combination are also examined.<>
{"title":"Edge-point correspondence in three views of a scene","authors":"N. Alvertos","doi":"10.1109/SSST.1990.138164","DOIUrl":"https://doi.org/10.1109/SSST.1990.138164","url":null,"abstract":"A stereo camera arrangement that results from combining the lateral model with the axial motion model provides three views of a scene to be utilized in a stereo correspondence algorithm. The third view of the scene serves as a verification of established correspondences between the other two. Only the correspondence of edge points is considered. Some geometrical relations underlying each model and their combination are also examined.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126512336","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138134
H. Chan, Y. Kakad
Linearized dynamical models of slew maneuvers of a large flexible spacecraft are utilized to design state feedback control systems to perform arbitrary slew maneuvers and to achieve total vibration suppression of flexible appendages. The control system designs are based on linear quadratic Gaussian loop transfer recovery (LQG/LTR) design methodology. The linearized slew maneuver equations used are derived from a nonlinear model developed for large-angle nonlinear arbitrary slew maneuvers and include 10-mode truncation for the vibrations of the flexible appendage. The slew maneuver control systems are developed for the combined problem of the slew maneuver of the entire assembly and the total vibration suppression of the appendage. The designs incorporate both the structured and the unstructured model uncertainties. The controller designs are further analyzed in terms of singular values and transmission zeros of the closed-loop transfer function matrix of the multivariable system. These singular values are utilized in studying the system sensitivity due to modal frequencies of the truncated model of the elastic member and the structural damping. The sensitivity study is further interpreted in terms of the robustness issues.<>
{"title":"Design issues in the control of large flexible spacecraft slew maneuvers","authors":"H. Chan, Y. Kakad","doi":"10.1109/SSST.1990.138134","DOIUrl":"https://doi.org/10.1109/SSST.1990.138134","url":null,"abstract":"Linearized dynamical models of slew maneuvers of a large flexible spacecraft are utilized to design state feedback control systems to perform arbitrary slew maneuvers and to achieve total vibration suppression of flexible appendages. The control system designs are based on linear quadratic Gaussian loop transfer recovery (LQG/LTR) design methodology. The linearized slew maneuver equations used are derived from a nonlinear model developed for large-angle nonlinear arbitrary slew maneuvers and include 10-mode truncation for the vibrations of the flexible appendage. The slew maneuver control systems are developed for the combined problem of the slew maneuver of the entire assembly and the total vibration suppression of the appendage. The designs incorporate both the structured and the unstructured model uncertainties. The controller designs are further analyzed in terms of singular values and transmission zeros of the closed-loop transfer function matrix of the multivariable system. These singular values are utilized in studying the system sensitivity due to modal frequencies of the truncated model of the elastic member and the structural damping. The sensitivity study is further interpreted in terms of the robustness issues.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125734816","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138200
A. Barbir, J. Aravena
A study is made of the operations of systolic arrays. A graph is developed to present array operation as a function of the compute cycle. A description is given of a computational procedure to determine such a graph. The graph representation is used to analyze the operation of an array and to detect special cases with reduced computational complexity. A matrix-vector multiplication array is used as a case study. Manipulation of the graph representation is used to determine sparsity patterns in the input data matrices. The resulting forms generate matrix products computable in reduced time.<>
{"title":"An approach for increasing the flexibility of systolic arrays","authors":"A. Barbir, J. Aravena","doi":"10.1109/SSST.1990.138200","DOIUrl":"https://doi.org/10.1109/SSST.1990.138200","url":null,"abstract":"A study is made of the operations of systolic arrays. A graph is developed to present array operation as a function of the compute cycle. A description is given of a computational procedure to determine such a graph. The graph representation is used to analyze the operation of an array and to detect special cases with reduced computational complexity. A matrix-vector multiplication array is used as a case study. Manipulation of the graph representation is used to determine sparsity patterns in the input data matrices. The resulting forms generate matrix products computable in reduced time.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116640298","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138158
H. Franke
A description is given of the implementation of a distributed robot simulation system on a VICTOR workstation, a multimode transputer-based computer developed at IBM. It is capable of graphically simulating large numbers of robot agents. The simulation task of each robot is functionally decomposed into subtasks, such as kinematics and graphics computation, which can be executed in parallel.<>
{"title":"Multirobot simulation in distributed systems","authors":"H. Franke","doi":"10.1109/SSST.1990.138158","DOIUrl":"https://doi.org/10.1109/SSST.1990.138158","url":null,"abstract":"A description is given of the implementation of a distributed robot simulation system on a VICTOR workstation, a multimode transputer-based computer developed at IBM. It is capable of graphically simulating large numbers of robot agents. The simulation task of each robot is functionally decomposed into subtasks, such as kinematics and graphics computation, which can be executed in parallel.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121364540","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}
Pub Date : 1990-03-11DOI: 10.1109/SSST.1990.138139
J. Foster, T. Wang
A uniform amplitude sampler is presented as an alternative to uniform time-sampling systems. Time code multiplexing (TCM) consists of an encoder and a decoder. The encoder transmits the quantized time intervals corresponding to the time at which the input signal passed through uniformly spaced amplitude levels. The decoder reconstructs the signal by using a sin(x)/x convolution in the amplitude instead of time domain. Even though the channel bit stream is variable rate, TCM systems can be effectively used with the packet-switched voice/data networks of today's technology. The Nyquist rate which exists for the bandlimited uniform time-sampling systems has a parallel Nyquist rate for uniform amplitude-sampling systems. However, TCM offers the advantage of being able to change the input signal bandwidth and therefore the minimum required sampling rate, which is not easily accomplished with uniform time-sampling systems. TCM data results are discussed, showing SNR-versus-bit-rate performance. Audio recordings of computer simulations are presented for 8-, 16-, and 24-kbit/s systems.<>
{"title":"Waveform coding using time code multiplexing","authors":"J. Foster, T. Wang","doi":"10.1109/SSST.1990.138139","DOIUrl":"https://doi.org/10.1109/SSST.1990.138139","url":null,"abstract":"A uniform amplitude sampler is presented as an alternative to uniform time-sampling systems. Time code multiplexing (TCM) consists of an encoder and a decoder. The encoder transmits the quantized time intervals corresponding to the time at which the input signal passed through uniformly spaced amplitude levels. The decoder reconstructs the signal by using a sin(x)/x convolution in the amplitude instead of time domain. Even though the channel bit stream is variable rate, TCM systems can be effectively used with the packet-switched voice/data networks of today's technology. The Nyquist rate which exists for the bandlimited uniform time-sampling systems has a parallel Nyquist rate for uniform amplitude-sampling systems. However, TCM offers the advantage of being able to change the input signal bandwidth and therefore the minimum required sampling rate, which is not easily accomplished with uniform time-sampling systems. TCM data results are discussed, showing SNR-versus-bit-rate performance. Audio recordings of computer simulations are presented for 8-, 16-, and 24-kbit/s systems.<<ETX>>","PeriodicalId":201543,"journal":{"name":"[1990] Proceedings. The Twenty-Second Southeastern Symposium on System Theory","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131547392","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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