Liang Boon Wee - Academia.edu (original) (raw)
Papers by Liang Boon Wee
The autonomous operation of free-flying robots in space requires the manipulation of objects with... more The autonomous operation of free-flying robots in space requires the manipulation of objects with unknown inertia properties. As a result, the combined inertia parameters of the end-effector and load cannot be determined a priori. This problem entails further research in the application of adaptive motion control strategies for space robots. Crucial to successful controller design is an accurate model of the underlying highly coupled nonlinear dynamics of multi-body space robots. Current techniques which use momentum conservation laws to obtain reduced order differential equations of motion provide models which do not depend affinely on the unknown inertia parameters of the robot system. Consequently, new models have to be developed to allow the synthesis of adaptive control strategies. This dissertation is concerned with the modeling of free-flying space robots and the design of adaptive motion control strategies. Specifically, we examine the generic case of articulated manipulator arms mounted on a satellite base which may or may not contain reaction wheels for satellite attitude control. The basis for our approach is the formulation of analytical models which depend affinely on the unknown inertia parameters of the system. Using these models we develop an adaptive joint space controller for the manipulator joints and an adaptive inertial space controller for the manipulator end-effector. A novel feature of our approach is that the parameter estimates are obtained using integrals of the motion only. Moreover, recursive algorithms are provided for efficient implementation of the adaptive controllers. Other new results in this work include the use of unit quaternions in defining orientation errors of the end-effector. This leads to adaptive control schemes which stabilize the robot system. Rigorous proofs of the stability properties are established using Lyapunov stability theory. Furthermore, simulation studies of the adaptive control schemes on two example space robot systems are used to verify the theoretical results.Ph.D.Aerospace engineeringApplied SciencesMechanicsSystems scienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/129094/2/9319654.pd
For space based robots in which the base is fl'ee to move, mo-tion planning and control is c... more For space based robots in which the base is fl'ee to move, mo-tion planning and control is complicated by uncertainties in the inertial properties of the manipulator and its load. This paper presents a new adaptive control method for space based robots which achieves globally stable trajectory tracking in the presence of uncertainties in the inertial parameters of the system. The paper begins with a partitioning of the fifteen degree of freedom system dynamics into two components: a nine degree of freedom invertible portion and a six degree of freedom non-invertible portion. The controller is then designed to achieve trajectory tracking of the invertible portion of the system. This portion of the system consist of the manipulator joint positions and the orientation of the base. The motion of the noninvertible portion is bounded, but unpredictable. This portion of the sys-tem consist of the position of the robot's base and the position of the reaction wheels. 1
IEEE Transactions on Robotics and Automation, 1997
ABSTRACT
This paper presents a Cartesian coordinate robot controller for use when the mass properties of t... more This paper presents a Cartesian coordinate robot controller for use when the mass properties of the load are unknown. The controller is demonstrated using a new simulation algorithm which is based on Hamilton's form of the equations of motion.
Proceedings. 1991 IEEE International Conference on Robotics and Automation
The authors present a novel adaptive control method for space-based robots which achieves globall... more The authors present a novel adaptive control method for space-based robots which achieves globally stable trajectory tracking in the presence of uncertainties in the inertial parameters of the system. They begin with a partitioning of the fifteen-degree-of-freedom system dynamics into two component: a nine-degree-of-freedom invertible portion and a six-degree-of-freedom noninvertible portion. The controller is then designed to achieve trajectory tracking of the invertible portion of the system. This portion of the system consists of the manipulator joint positions and the orientation of the base. The motion of the noninvertible portion is bounded but unpredictable. This portion of the system consists of the position of the robot's base and the position of the reaction wheels. Simulation results are presented on a space-based robot with five revolute joints and one prismatic joint.<<ETX>>
2020 IEEE/ION Position, Location and Navigation Symposium (PLANS), 2020
In this paper we present a unified method for vision-aided Navigation applied to autonomous syste... more In this paper we present a unified method for vision-aided Navigation applied to autonomous systems. Traditionally, vision aided navigation methods can be broadly classified under two approaches: (a) methods that relies only on features available in the scene, and (b) methods that uses registered models of the environments. The first approach employs features tracking that provides only partial navigation aiding. In order to achieve full localization, the second approach that uses registered models of the environment is needed. These environment models could be derived from man-made fiducial or structures of natural terrain. The main drawback of the disparate approaches is due to the lack of navigation solution that is scalable under different conditions.
performance compared to traditional SMA actuators. This actuator is composed of two antagonistic ... more performance compared to traditional SMA actuators. This actuator is composed of two antagonistic SMA wires and a mechanical joint coupled with a torsion spring. The torsion spring is employed to reduce the total stiffness of SMA actuator and improve the range of motion. The antagonistic wires increase the response time as one wire can be heated up while the other wire is still in the cooling process. Dynamic model of this actuator was established for control design. Experimental results proved that this new actuator can provide larger output range of motion and faster response speed than traditional SMA actuators under the same conditions. Sine wave tracking with 0.05 Hz, 0.08 Hz and 0.1 Hz were performed and our results demonstrated that this compliant actuator has good tracking performance under simple PID control.
1992 American Control Conference, Jun 24, 1992
This paper is concerned with the study of contact between free-flying space robots, and the minim... more This paper is concerned with the study of contact between free-flying space robots, and the minimization of the impulse at impact. The paper begins with a presentation of a new model of space robots which takes into account external applied forces. Next a contact model which consider both linear and angular motion between contacting systems is presented. Two approaches for trajectory planning in Cartesian space are discussed, and a strategy for achieving both the primary objective of trajectory tracking in Cartesian space and the secondary objective of impact minimization through configuration space planning is presented. The strategy is tested on a 15 degree of freedom space robot and simulation results are presented.
Trends in Food Science & Technology, 1991
This paper presents a Cartesian coordinate robot controller for use when the mass properties of t... more This paper presents a Cartesian coordinate robot controller for use when the mass properties of the load are unknown. The controller is demonstrated using a new simulation algorithm which is based on Hamilton's form of the equations of motion.
Stroke, Feb 1, 2012
Introduction: Cross-cultural differences could influence the relationship between caregiving and ... more Introduction: Cross-cultural differences could influence the relationship between caregiving and rehabilitation outcomes in stroke survivors between different societies. We aimed to determine independent factors of rehabilitation effectiveness (REs) and rehabilitation efficiency (REy) amongst recent stroke survivors in Singapore, and examine if having a caregiver affected these outcomes. Methods: We retrospectively studied all stroke patients fulfilling inclusion criteria (n=3796) from all Singaporean rehabilitation hospitals from 1996-2005. We used backward mixed model linear regression (multivariate) to test the relationship between independent variables and REs and REy. Admission and discharge Shah-modified Barthel Indices were used to calculate REs and REy. We further explored the effect of caregiver availability, number of caregivers, and relationship of caregiver to patient on REs and REy. Mixed logistic regression identified independent predictors of caregiver availability and caregiver relationship to patient, mixed Poisson modelling identified independent predictors of caregiver number; mixed linear regression identified the relationship of REy and REs with caregiver factors. Results: Having a caregiver independently predicted poorer REs and log REy; other predictors included older age, Malay ethnicity, ischemic stroke, longer time to admission, dementia. Within our population, 95.8% (3640/3796) had caregivers and 94.2% (3429/3640) of them provided physical care (defined as primary caregivers). Of patients with primary caregivers, 41.2% relied on live-in hired help (foreign domestic workers, FDWs), 27.6% on spouses and 21.6% on first-degree relatives. Independent factors associated with caregiver availability and number were older age, female, being married, higher socioeconomic status, and having a religion (all p<0.05). Compared to those who had spouse as primary caregiver, having a child or parent (β=-4.1, 95%CI=-8.0 to -0.1, p=0.042) or FDW (β=-6.9, 95%CI=-9.9 to -3.9, p<0.001) as primary caregiver were predictive of poorer REs, while having a child or parent (β=-0.140, 95%CI=-0.280 to 0.001, p=0.052) or FDW (β=-0.110, 95%CI=-0.210 to -0.001, p=0.048) as primary caregiver were predictive of poorer log REy. Conclusions: In this Asian population, having a caregiver was surprisingly associated with poorer REs and REy in stroke patients, perhaps due to differing socio-cultural contexts; only 49.2% of patients depended on spouse/near relatives as primary caregivers, compared with higher estimates in Western populations. REs further declined with decreasing closeness of relationship between primary caregiver and patient, and REy was poorer in patients with hired help as primary caregivers. Perhaps the role of hired help in stroke caregiving should be re-thought, as dependence on FDWs is high in many Asian cities due to population ageing.
Sensors and Actuators A: Physical, 2015
This paper presents the design and control of a novel compliant differential shape memory alloy (... more This paper presents the design and control of a novel compliant differential shape memory alloy (SMA) actuator with significantly improved performance compared to traditional bias and differential type SMA actuators. This actuator is composed of two antagonistic SMA wires and a mechanical joint coupled with a torsion spring. The differential SMA wires are utilized to increase the response speed, and the torsion spring is employed to reduce the total stiffness of SMA actuator and improve the output range. Theoretical models that include the stiffness equations of the SMA wire as well as the dynamics of three different SMA actuation systems are introduced and compared. Simulation and experimental results have proved that this new actuator can provide larger output angle compared to conventional SMA actuators under the same conditions. Moreover, regulation and tracking control experiments have demonstrated that this compliant differential SMA actuator achieves higher response speed compared to the bias SMA actuator using compatible PI controller. The tracking performance is further improved by the saturated PI controller.
IECON '87: Industrial Applications of Control and Simulation, 1987
ABSTRACT
Singapore International Conference on Intelligent Control and Instrumentation [Proceedings 1992], 1992
This paper present a new formulation of the dynamical equations of motion for space based systems... more This paper present a new formulation of the dynamical equations of motion for space based systems which do not require any assumptions on zero applied forces. Moreover, the inertia properties of the system may be unknown. The free-flying base of the system is modelled with a six degree of freedom fictitious robot. The joints of the fictitious robot are unactuated
Guidance, Navigation, and Control Conference, 1995
The equations of motion for Bank-To-Turn steering of an aircraft are coupled via the high roll ra... more The equations of motion for Bank-To-Turn steering of an aircraft are coupled via the high roll rates. As a result classical linearized autopilot designs with gain scheduling will produce limited performance. This paper presents a nonlinear control that takes into consideration the fully coupled and nonlinear dynamics of the airframe. Practical issues such as the effects of parametric uncertainties and state estimation errors on the stability of the closed loop control system are discussed. The performance and robustness of the nonlinear controller to actuator saturation are verified via computer simulations using aerodynamic data of a typical fighter aircraft.
2013 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2013
This paper presents a novel compliant differential (CD) Shape Memory Alloy (SMA) actuator with im... more This paper presents a novel compliant differential (CD) Shape Memory Alloy (SMA) actuator with improved performance compared to traditional SMA actuators. This actuator is composed of two antagonistic SMA wires and a mechanical joint coupled with a torsion spring. The torsion spring is employed to reduce the total stiffness of SMA actuator and improve the range of motion. The antagonistic wires increase the response time as one wire can be heated up while the other wire is still in the cooling process. Dynamic model of this actuator was established for control design. Experimental results proved that this new actuator can provide larger output range of motion and faster response speed than traditional SMA actuators under the same conditions. Sine wave tracking with 0.05 Hz, 0.08 Hz and 0.1 Hz were performed and our results demonstrated that this compliant actuator has good tracking performance under simple PID control.
IEEE ICCA 2010, 2010
This paper presents a passivity-based control strategy for satellite stabilization using internal... more This paper presents a passivity-based control strategy for satellite stabilization using internal control torques which preserves the total momentum of the system. The control law does not require a-priori knowledge of the satellite inertia information and is robust to un-modeled dynamics. The satellite system we consider uses n reaction wheels for reorientation maneuvers. The dynamical equations of motion of the
This paper present a new formulation of the dynamical equations of motion for space based systems... more This paper present a new formulation of the dynamical equations of motion for space based systems which do not require any assumptions on zero applied forces. Moreover, the inertia properties of the system may be unknown. The free-flying base of the system is modelled with a six degree of freedom fictitious robot. The joints of the fictitious robot are unactuated
Trends in Food Science & Technology, 1991
This paper presents a Cartesian coordinate robot controller for use when the mass properties of t... more This paper presents a Cartesian coordinate robot controller for use when the mass properties of the load are unknown. The controller is demonstrated using a new simulation algorithm which is based on Hamilton's form of the equations of motion.
This paper presents a passivity-based control strategy for satellite stabilization using internal... more This paper presents a passivity-based control strategy for satellite stabilization using internal control torques which preserves the total momentum of the system. The control law does not require a-priori knowledge of the satellite inertia information and is robust to un-modeled dynamics. The satellite system we consider uses n reaction wheels for reorientation maneuvers. The dynamical equations of motion of the
The autonomous operation of free-flying robots in space requires the manipulation of objects with... more The autonomous operation of free-flying robots in space requires the manipulation of objects with unknown inertia properties. As a result, the combined inertia parameters of the end-effector and load cannot be determined a priori. This problem entails further research in the application of adaptive motion control strategies for space robots. Crucial to successful controller design is an accurate model of the underlying highly coupled nonlinear dynamics of multi-body space robots. Current techniques which use momentum conservation laws to obtain reduced order differential equations of motion provide models which do not depend affinely on the unknown inertia parameters of the robot system. Consequently, new models have to be developed to allow the synthesis of adaptive control strategies. This dissertation is concerned with the modeling of free-flying space robots and the design of adaptive motion control strategies. Specifically, we examine the generic case of articulated manipulator arms mounted on a satellite base which may or may not contain reaction wheels for satellite attitude control. The basis for our approach is the formulation of analytical models which depend affinely on the unknown inertia parameters of the system. Using these models we develop an adaptive joint space controller for the manipulator joints and an adaptive inertial space controller for the manipulator end-effector. A novel feature of our approach is that the parameter estimates are obtained using integrals of the motion only. Moreover, recursive algorithms are provided for efficient implementation of the adaptive controllers. Other new results in this work include the use of unit quaternions in defining orientation errors of the end-effector. This leads to adaptive control schemes which stabilize the robot system. Rigorous proofs of the stability properties are established using Lyapunov stability theory. Furthermore, simulation studies of the adaptive control schemes on two example space robot systems are used to verify the theoretical results.Ph.D.Aerospace engineeringApplied SciencesMechanicsSystems scienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/129094/2/9319654.pd
For space based robots in which the base is fl'ee to move, mo-tion planning and control is c... more For space based robots in which the base is fl'ee to move, mo-tion planning and control is complicated by uncertainties in the inertial properties of the manipulator and its load. This paper presents a new adaptive control method for space based robots which achieves globally stable trajectory tracking in the presence of uncertainties in the inertial parameters of the system. The paper begins with a partitioning of the fifteen degree of freedom system dynamics into two components: a nine degree of freedom invertible portion and a six degree of freedom non-invertible portion. The controller is then designed to achieve trajectory tracking of the invertible portion of the system. This portion of the system consist of the manipulator joint positions and the orientation of the base. The motion of the noninvertible portion is bounded, but unpredictable. This portion of the sys-tem consist of the position of the robot's base and the position of the reaction wheels. 1
IEEE Transactions on Robotics and Automation, 1997
ABSTRACT
This paper presents a Cartesian coordinate robot controller for use when the mass properties of t... more This paper presents a Cartesian coordinate robot controller for use when the mass properties of the load are unknown. The controller is demonstrated using a new simulation algorithm which is based on Hamilton's form of the equations of motion.
Proceedings. 1991 IEEE International Conference on Robotics and Automation
The authors present a novel adaptive control method for space-based robots which achieves globall... more The authors present a novel adaptive control method for space-based robots which achieves globally stable trajectory tracking in the presence of uncertainties in the inertial parameters of the system. They begin with a partitioning of the fifteen-degree-of-freedom system dynamics into two component: a nine-degree-of-freedom invertible portion and a six-degree-of-freedom noninvertible portion. The controller is then designed to achieve trajectory tracking of the invertible portion of the system. This portion of the system consists of the manipulator joint positions and the orientation of the base. The motion of the noninvertible portion is bounded but unpredictable. This portion of the system consists of the position of the robot's base and the position of the reaction wheels. Simulation results are presented on a space-based robot with five revolute joints and one prismatic joint.<<ETX>>
2020 IEEE/ION Position, Location and Navigation Symposium (PLANS), 2020
In this paper we present a unified method for vision-aided Navigation applied to autonomous syste... more In this paper we present a unified method for vision-aided Navigation applied to autonomous systems. Traditionally, vision aided navigation methods can be broadly classified under two approaches: (a) methods that relies only on features available in the scene, and (b) methods that uses registered models of the environments. The first approach employs features tracking that provides only partial navigation aiding. In order to achieve full localization, the second approach that uses registered models of the environment is needed. These environment models could be derived from man-made fiducial or structures of natural terrain. The main drawback of the disparate approaches is due to the lack of navigation solution that is scalable under different conditions.
performance compared to traditional SMA actuators. This actuator is composed of two antagonistic ... more performance compared to traditional SMA actuators. This actuator is composed of two antagonistic SMA wires and a mechanical joint coupled with a torsion spring. The torsion spring is employed to reduce the total stiffness of SMA actuator and improve the range of motion. The antagonistic wires increase the response time as one wire can be heated up while the other wire is still in the cooling process. Dynamic model of this actuator was established for control design. Experimental results proved that this new actuator can provide larger output range of motion and faster response speed than traditional SMA actuators under the same conditions. Sine wave tracking with 0.05 Hz, 0.08 Hz and 0.1 Hz were performed and our results demonstrated that this compliant actuator has good tracking performance under simple PID control.
1992 American Control Conference, Jun 24, 1992
This paper is concerned with the study of contact between free-flying space robots, and the minim... more This paper is concerned with the study of contact between free-flying space robots, and the minimization of the impulse at impact. The paper begins with a presentation of a new model of space robots which takes into account external applied forces. Next a contact model which consider both linear and angular motion between contacting systems is presented. Two approaches for trajectory planning in Cartesian space are discussed, and a strategy for achieving both the primary objective of trajectory tracking in Cartesian space and the secondary objective of impact minimization through configuration space planning is presented. The strategy is tested on a 15 degree of freedom space robot and simulation results are presented.
Trends in Food Science & Technology, 1991
This paper presents a Cartesian coordinate robot controller for use when the mass properties of t... more This paper presents a Cartesian coordinate robot controller for use when the mass properties of the load are unknown. The controller is demonstrated using a new simulation algorithm which is based on Hamilton's form of the equations of motion.
Stroke, Feb 1, 2012
Introduction: Cross-cultural differences could influence the relationship between caregiving and ... more Introduction: Cross-cultural differences could influence the relationship between caregiving and rehabilitation outcomes in stroke survivors between different societies. We aimed to determine independent factors of rehabilitation effectiveness (REs) and rehabilitation efficiency (REy) amongst recent stroke survivors in Singapore, and examine if having a caregiver affected these outcomes. Methods: We retrospectively studied all stroke patients fulfilling inclusion criteria (n=3796) from all Singaporean rehabilitation hospitals from 1996-2005. We used backward mixed model linear regression (multivariate) to test the relationship between independent variables and REs and REy. Admission and discharge Shah-modified Barthel Indices were used to calculate REs and REy. We further explored the effect of caregiver availability, number of caregivers, and relationship of caregiver to patient on REs and REy. Mixed logistic regression identified independent predictors of caregiver availability and caregiver relationship to patient, mixed Poisson modelling identified independent predictors of caregiver number; mixed linear regression identified the relationship of REy and REs with caregiver factors. Results: Having a caregiver independently predicted poorer REs and log REy; other predictors included older age, Malay ethnicity, ischemic stroke, longer time to admission, dementia. Within our population, 95.8% (3640/3796) had caregivers and 94.2% (3429/3640) of them provided physical care (defined as primary caregivers). Of patients with primary caregivers, 41.2% relied on live-in hired help (foreign domestic workers, FDWs), 27.6% on spouses and 21.6% on first-degree relatives. Independent factors associated with caregiver availability and number were older age, female, being married, higher socioeconomic status, and having a religion (all p<0.05). Compared to those who had spouse as primary caregiver, having a child or parent (β=-4.1, 95%CI=-8.0 to -0.1, p=0.042) or FDW (β=-6.9, 95%CI=-9.9 to -3.9, p<0.001) as primary caregiver were predictive of poorer REs, while having a child or parent (β=-0.140, 95%CI=-0.280 to 0.001, p=0.052) or FDW (β=-0.110, 95%CI=-0.210 to -0.001, p=0.048) as primary caregiver were predictive of poorer log REy. Conclusions: In this Asian population, having a caregiver was surprisingly associated with poorer REs and REy in stroke patients, perhaps due to differing socio-cultural contexts; only 49.2% of patients depended on spouse/near relatives as primary caregivers, compared with higher estimates in Western populations. REs further declined with decreasing closeness of relationship between primary caregiver and patient, and REy was poorer in patients with hired help as primary caregivers. Perhaps the role of hired help in stroke caregiving should be re-thought, as dependence on FDWs is high in many Asian cities due to population ageing.
Sensors and Actuators A: Physical, 2015
This paper presents the design and control of a novel compliant differential shape memory alloy (... more This paper presents the design and control of a novel compliant differential shape memory alloy (SMA) actuator with significantly improved performance compared to traditional bias and differential type SMA actuators. This actuator is composed of two antagonistic SMA wires and a mechanical joint coupled with a torsion spring. The differential SMA wires are utilized to increase the response speed, and the torsion spring is employed to reduce the total stiffness of SMA actuator and improve the output range. Theoretical models that include the stiffness equations of the SMA wire as well as the dynamics of three different SMA actuation systems are introduced and compared. Simulation and experimental results have proved that this new actuator can provide larger output angle compared to conventional SMA actuators under the same conditions. Moreover, regulation and tracking control experiments have demonstrated that this compliant differential SMA actuator achieves higher response speed compared to the bias SMA actuator using compatible PI controller. The tracking performance is further improved by the saturated PI controller.
IECON '87: Industrial Applications of Control and Simulation, 1987
ABSTRACT
Singapore International Conference on Intelligent Control and Instrumentation [Proceedings 1992], 1992
This paper present a new formulation of the dynamical equations of motion for space based systems... more This paper present a new formulation of the dynamical equations of motion for space based systems which do not require any assumptions on zero applied forces. Moreover, the inertia properties of the system may be unknown. The free-flying base of the system is modelled with a six degree of freedom fictitious robot. The joints of the fictitious robot are unactuated
Guidance, Navigation, and Control Conference, 1995
The equations of motion for Bank-To-Turn steering of an aircraft are coupled via the high roll ra... more The equations of motion for Bank-To-Turn steering of an aircraft are coupled via the high roll rates. As a result classical linearized autopilot designs with gain scheduling will produce limited performance. This paper presents a nonlinear control that takes into consideration the fully coupled and nonlinear dynamics of the airframe. Practical issues such as the effects of parametric uncertainties and state estimation errors on the stability of the closed loop control system are discussed. The performance and robustness of the nonlinear controller to actuator saturation are verified via computer simulations using aerodynamic data of a typical fighter aircraft.
2013 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2013
This paper presents a novel compliant differential (CD) Shape Memory Alloy (SMA) actuator with im... more This paper presents a novel compliant differential (CD) Shape Memory Alloy (SMA) actuator with improved performance compared to traditional SMA actuators. This actuator is composed of two antagonistic SMA wires and a mechanical joint coupled with a torsion spring. The torsion spring is employed to reduce the total stiffness of SMA actuator and improve the range of motion. The antagonistic wires increase the response time as one wire can be heated up while the other wire is still in the cooling process. Dynamic model of this actuator was established for control design. Experimental results proved that this new actuator can provide larger output range of motion and faster response speed than traditional SMA actuators under the same conditions. Sine wave tracking with 0.05 Hz, 0.08 Hz and 0.1 Hz were performed and our results demonstrated that this compliant actuator has good tracking performance under simple PID control.
IEEE ICCA 2010, 2010
This paper presents a passivity-based control strategy for satellite stabilization using internal... more This paper presents a passivity-based control strategy for satellite stabilization using internal control torques which preserves the total momentum of the system. The control law does not require a-priori knowledge of the satellite inertia information and is robust to un-modeled dynamics. The satellite system we consider uses n reaction wheels for reorientation maneuvers. The dynamical equations of motion of the
This paper present a new formulation of the dynamical equations of motion for space based systems... more This paper present a new formulation of the dynamical equations of motion for space based systems which do not require any assumptions on zero applied forces. Moreover, the inertia properties of the system may be unknown. The free-flying base of the system is modelled with a six degree of freedom fictitious robot. The joints of the fictitious robot are unactuated
Trends in Food Science & Technology, 1991
This paper presents a Cartesian coordinate robot controller for use when the mass properties of t... more This paper presents a Cartesian coordinate robot controller for use when the mass properties of the load are unknown. The controller is demonstrated using a new simulation algorithm which is based on Hamilton's form of the equations of motion.
This paper presents a passivity-based control strategy for satellite stabilization using internal... more This paper presents a passivity-based control strategy for satellite stabilization using internal control torques which preserves the total momentum of the system. The control law does not require a-priori knowledge of the satellite inertia information and is robust to un-modeled dynamics. The satellite system we consider uses n reaction wheels for reorientation maneuvers. The dynamical equations of motion of the