Petko Kiriazov | Bulgarian Academy of Sciences (original) (raw)
Papers by Petko Kiriazov
Progress and Trends in Rheology II, 1988
Solid State Phenomena, May 15, 2013
Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active s... more Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active suspension, and other engineering structures with active vibration/shape control. CMS have to be considered as functionally directed compositions of mutually influencing subsystems: control, actuator, structural, and sensor subsystems. Such systems have highly complex dynamics and an advanced conceptual framework is needed that considers at the same time the problems of full dynamic modelling, optimal system design, accurate parameter identification, and optimal robust control. There are various design tasks for controlled mechanical systems (CMS), where continuously increasing demands for higher speed, better motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study their controllability and find efficient solutions for the control-related, design optimization problems. Our intention is to present novel concepts and criteria for design optimization of CMS with decentralized controllers at the lowest (joint) level. The first step is to find a dynamic model relating the control inputs and the controlled outputs which is suitable for both purposes: accurate parameter identification and robust control design. To do that, we can apply the so-called multibody system approach: the mechanical structure of CMS can be approximated by a composition of rigid bodies connected by joints, actuators, springs, and dampers. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Thus the design optimization process has to involve, besides the basic strength/load capacity criterion, additional design relations for optimal trade-off between the bounds of disturbances and the control force limits. The proposed approach enables decomposing the complex CMS design task into much simpler optimization problems for the CMS components: mechanical structure, actuators, sensors, and controllers. The new design concepts will be illustrated with several optimization examples of CMS concerning their shape, mass distribution, actuators' sizes and locations, and control functions.
ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously ... more ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously increasing demands for higher speed, improved motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study MS controllability and their design criteria. An explicit, necessary and sufficient condition has been found to guarantee robustness of decentralized controllers against arbitrary, but bounded disturbances. Thus the feedback control design can be based on optimal trade-off relationships between the bounds of disturbances and the control force limits. These and other reasonable design criteria will be considered in this paper. The design concepts will be illustrated with several examples concerning shape, mass distribution, as well as actuators sizes and locations of controlled MS.
Solid State Phenomena, 2013
Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active s... more Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active suspension, and other engineering structures with active vibration/shape control. CMS have to be considered as functionally directed compositions of mutually influencing subsystems: control, actuator, structural, and sensor subsystems. Such systems have highly complex dynamics and an advanced conceptual framework is needed that considers at the same time the problems of full dynamic modelling, optimal system design, accurate parameter identification, and optimal robust control. There are various design tasks for controlled mechanical systems (CMS), where continuously increasing demands for higher speed, better motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study their controllability and find efficient solutions for the control-related, design optimization problems. Our intention is to present novel concepts and criteria for design optimization of CMS with decentralized controllers at the lowest (joint) level. The first step is to find a dynamic model relating the control inputs and the controlled outputs which is suitable for both purposes: accurate parameter identification and robust control design. To do that, we can apply the so-called multibody system approach: the mechanical structure of CMS can be approximated by a composition of rigid bodies connected by joints, actuators, springs, and dampers. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Thus the design optimization process has to involve, besides the basic strength/load capacity criterion, additional design relations for optimal trade-off between the bounds of disturbances and the control force limits. The proposed approach enables decomposing the complex CMS design task into much simpler optimization problems for the CMS components: mechanical structure, actuators, sensors, and controllers. The new design concepts will be illustrated with several optimization examples of CMS concerning their shape, mass distribution, actuators' sizes and locations, and control functions.
8th IFAC Conference on Control Applications in Marine Systems (2010), 2010
ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously ... more ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously increasing demands for higher speed, improved motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study MS controllability and their design criteria. An explicit, necessary and sufficient condition has been found to guarantee robustness of decentralized controllers against arbitrary, but bounded disturbances. Thus the feedback control design can be based on optimal trade-off relationships between the bounds of disturbances and the control force limits. These and other reasonable design criteria will be considered in this paper. The design concepts will be illustrated with several examples concerning shape, mass distribution, as well as actuators sizes and locations of controlled MS.
ABSTRACT In many cases, suspended rigid or flexible multibody systems MBS perform undesirable vib... more ABSTRACT In many cases, suspended rigid or flexible multibody systems MBS perform undesirable vibrations in the low frequency domain which can not be efficiently reduced applying only passive control strategies. Active control is, of course, needed in the case of desirable forced vibrations, too. The goal of the proposed paper is to develop a unified approach to the optimal design of actuator systems realizing decentralized vibration control.
The paper presents a unified approach for decentralized feedback control of multibody systems (MB... more The paper presents a unified approach for decentralized feedback control of multibody systems (MBS) in the face of bounded parameter inaccuracies and random disturbances. The approach is based on optimal trade-off relations between the given bounds of perturbations, the system output accuracy, and the control force limits. Several examples will be given to show the applicability of the proposed control design concepts to various-type MBS.
Articulated structures such as humans or animals have many joints and complex multibody and muscl... more Articulated structures such as humans or animals have many joints and complex multibody and muscle dynamics. A challenging issue is how these largescale musculo-skeletal systems are efficiently controlled in dynamic locomotion tasks like walking or running. In such tasks, control functions (neural signals to muscles) have to achieve optimal trade-off between, at least, three important but contradicting performance indices: locomotion speed, accuracy of steps, and energy consumption.
Abstract A global dynamic performance measure for manipulators with decentralized control systems... more Abstract A global dynamic performance measure for manipulators with decentralized control systems is given. The measure is defined on the base of a weak explicit condition on the inverse inertia matrix which is necessary and sufficient for a manipulator to be independent joint controllable (IJC). Most properly designed nonredundant manipulators can be IJC. For a planar three-degree-of-freedom manipulator to be IJC, a simple inequality is derived to show how the link masses should decrease in progressing from the base to the gripper
For control purposes in robotics or rehabilitation, we may use properly simplified dynamic models... more For control purposes in robotics or rehabilitation, we may use properly simplified dynamic models with a reduced number of degrees of freedom. First, we define a set of variables that best characterize its dynamic performance in the required motion task. Second, driving forces/torques are properly assigned in order to achieve the required dynamic performance in an efficient way. The usual performance requirements are for positioning accuracy, movement execution time, and energy expenditure.
Résumé/Abstract The performance of various-type dynamical systems in point-to-point operation can... more Résumé/Abstract The performance of various-type dynamical systems in point-to-point operation can be considerably improved by using properly parameterized control functions. Control limitations are inherently satisfied and state constraints can be observed. Optimal values of the control parameters are obtained in a two-level parametric optimization procedure. At the first level, the two-point boundary-value problem (TPBVP) is solved and at the second-optimization of the performance index.
Abstract: We propose control strategy for humans that have to perform goal-directed motion tasks ... more Abstract: We propose control strategy for humans that have to perform goal-directed motion tasks and/or posture stabilization tasks. First, we define a set of variables that best characterize the dynamic performance of the controlled system in the required motion task. Second, driving forces/torques are properly assigned in order to achieve the required dynamic performance in an efficient way. The usual performance requirements are for positioning accuracy, movement response, and energy expenditure.
Progress and Trends in Rheology II, 1988
Solid State Phenomena, May 15, 2013
Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active s... more Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active suspension, and other engineering structures with active vibration/shape control. CMS have to be considered as functionally directed compositions of mutually influencing subsystems: control, actuator, structural, and sensor subsystems. Such systems have highly complex dynamics and an advanced conceptual framework is needed that considers at the same time the problems of full dynamic modelling, optimal system design, accurate parameter identification, and optimal robust control. There are various design tasks for controlled mechanical systems (CMS), where continuously increasing demands for higher speed, better motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study their controllability and find efficient solutions for the control-related, design optimization problems. Our intention is to present novel concepts and criteria for design optimization of CMS with decentralized controllers at the lowest (joint) level. The first step is to find a dynamic model relating the control inputs and the controlled outputs which is suitable for both purposes: accurate parameter identification and robust control design. To do that, we can apply the so-called multibody system approach: the mechanical structure of CMS can be approximated by a composition of rigid bodies connected by joints, actuators, springs, and dampers. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Thus the design optimization process has to involve, besides the basic strength/load capacity criterion, additional design relations for optimal trade-off between the bounds of disturbances and the control force limits. The proposed approach enables decomposing the complex CMS design task into much simpler optimization problems for the CMS components: mechanical structure, actuators, sensors, and controllers. The new design concepts will be illustrated with several optimization examples of CMS concerning their shape, mass distribution, actuators' sizes and locations, and control functions.
ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously ... more ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously increasing demands for higher speed, improved motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study MS controllability and their design criteria. An explicit, necessary and sufficient condition has been found to guarantee robustness of decentralized controllers against arbitrary, but bounded disturbances. Thus the feedback control design can be based on optimal trade-off relationships between the bounds of disturbances and the control force limits. These and other reasonable design criteria will be considered in this paper. The design concepts will be illustrated with several examples concerning shape, mass distribution, as well as actuators sizes and locations of controlled MS.
Solid State Phenomena, 2013
Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active s... more Controlled mechanical systems (CMS) are various robotic systems, vehicles/platforms with active suspension, and other engineering structures with active vibration/shape control. CMS have to be considered as functionally directed compositions of mutually influencing subsystems: control, actuator, structural, and sensor subsystems. Such systems have highly complex dynamics and an advanced conceptual framework is needed that considers at the same time the problems of full dynamic modelling, optimal system design, accurate parameter identification, and optimal robust control. There are various design tasks for controlled mechanical systems (CMS), where continuously increasing demands for higher speed, better motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study their controllability and find efficient solutions for the control-related, design optimization problems. Our intention is to present novel concepts and criteria for design optimization of CMS with decentralized controllers at the lowest (joint) level. The first step is to find a dynamic model relating the control inputs and the controlled outputs which is suitable for both purposes: accurate parameter identification and robust control design. To do that, we can apply the so-called multibody system approach: the mechanical structure of CMS can be approximated by a composition of rigid bodies connected by joints, actuators, springs, and dampers. Then we find explicit necessary and sufficient conditions on the control transfer matrix that can guarantee robust controllability in the face of arbitrary, but bounded disturbances. Thus the design optimization process has to involve, besides the basic strength/load capacity criterion, additional design relations for optimal trade-off between the bounds of disturbances and the control force limits. The proposed approach enables decomposing the complex CMS design task into much simpler optimization problems for the CMS components: mechanical structure, actuators, sensors, and controllers. The new design concepts will be illustrated with several optimization examples of CMS concerning their shape, mass distribution, actuators' sizes and locations, and control functions.
8th IFAC Conference on Control Applications in Marine Systems (2010), 2010
ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously ... more ABSTRACT There are various designs and control tasks for marine systems (MS), where continuously increasing demands for higher speed, improved motion accuracy, and reduced energy consumption are to be satisfied. In order to achieve such complicated performance optimization, it is very important to study MS controllability and their design criteria. An explicit, necessary and sufficient condition has been found to guarantee robustness of decentralized controllers against arbitrary, but bounded disturbances. Thus the feedback control design can be based on optimal trade-off relationships between the bounds of disturbances and the control force limits. These and other reasonable design criteria will be considered in this paper. The design concepts will be illustrated with several examples concerning shape, mass distribution, as well as actuators sizes and locations of controlled MS.
ABSTRACT In many cases, suspended rigid or flexible multibody systems MBS perform undesirable vib... more ABSTRACT In many cases, suspended rigid or flexible multibody systems MBS perform undesirable vibrations in the low frequency domain which can not be efficiently reduced applying only passive control strategies. Active control is, of course, needed in the case of desirable forced vibrations, too. The goal of the proposed paper is to develop a unified approach to the optimal design of actuator systems realizing decentralized vibration control.
The paper presents a unified approach for decentralized feedback control of multibody systems (MB... more The paper presents a unified approach for decentralized feedback control of multibody systems (MBS) in the face of bounded parameter inaccuracies and random disturbances. The approach is based on optimal trade-off relations between the given bounds of perturbations, the system output accuracy, and the control force limits. Several examples will be given to show the applicability of the proposed control design concepts to various-type MBS.
Articulated structures such as humans or animals have many joints and complex multibody and muscl... more Articulated structures such as humans or animals have many joints and complex multibody and muscle dynamics. A challenging issue is how these largescale musculo-skeletal systems are efficiently controlled in dynamic locomotion tasks like walking or running. In such tasks, control functions (neural signals to muscles) have to achieve optimal trade-off between, at least, three important but contradicting performance indices: locomotion speed, accuracy of steps, and energy consumption.
Abstract A global dynamic performance measure for manipulators with decentralized control systems... more Abstract A global dynamic performance measure for manipulators with decentralized control systems is given. The measure is defined on the base of a weak explicit condition on the inverse inertia matrix which is necessary and sufficient for a manipulator to be independent joint controllable (IJC). Most properly designed nonredundant manipulators can be IJC. For a planar three-degree-of-freedom manipulator to be IJC, a simple inequality is derived to show how the link masses should decrease in progressing from the base to the gripper
For control purposes in robotics or rehabilitation, we may use properly simplified dynamic models... more For control purposes in robotics or rehabilitation, we may use properly simplified dynamic models with a reduced number of degrees of freedom. First, we define a set of variables that best characterize its dynamic performance in the required motion task. Second, driving forces/torques are properly assigned in order to achieve the required dynamic performance in an efficient way. The usual performance requirements are for positioning accuracy, movement execution time, and energy expenditure.
Résumé/Abstract The performance of various-type dynamical systems in point-to-point operation can... more Résumé/Abstract The performance of various-type dynamical systems in point-to-point operation can be considerably improved by using properly parameterized control functions. Control limitations are inherently satisfied and state constraints can be observed. Optimal values of the control parameters are obtained in a two-level parametric optimization procedure. At the first level, the two-point boundary-value problem (TPBVP) is solved and at the second-optimization of the performance index.
Abstract: We propose control strategy for humans that have to perform goal-directed motion tasks ... more Abstract: We propose control strategy for humans that have to perform goal-directed motion tasks and/or posture stabilization tasks. First, we define a set of variables that best characterize the dynamic performance of the controlled system in the required motion task. Second, driving forces/torques are properly assigned in order to achieve the required dynamic performance in an efficient way. The usual performance requirements are for positioning accuracy, movement response, and energy expenditure.