Suiyang Khoo - Academia.edu (original) (raw)

Papers by Suiyang Khoo

IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2019

The hexapod manipulator is the most common motion platform, which is widely used as a simulation-... more The hexapod manipulator is the most common motion platform, which is widely used as a simulation-based motion platform (SBMP). As the hexapod manipulator has a limited workspace, it is not physically possible to regenerate the real vehicle motion signals using the SBMP. The motion cueing algorithm (MCA) is responsible for regenerating a realistic vehicle motion sensation for the user when the SBMP operates within its physical and dynamical limitations. Recently, model predictive control (MPC) has been introduced to extract the optimal input motion signals while considering the SBMP limitations in the Cartesian coordinate space, which leads to a linear time-invariant (LTI) MPC-based MCA methods. Unfortunately, the existing LTI MPC-based MCA methods are still not able to consider the parameters of the SBMP’s hexapod mechanisms inside their models. In general, the current studies only consider the constraints in the Cartesian coordinate system of the hexapod mechanism, instead of its design parameters. This consideration results in a poor usage of the hexapod workspace due to the conservative assumptions; consequently, the SBMP users do not experience realistic motions. The main contribution of this article is to take the SBMP’s physical limitations into account in the MPC model such that more precise motion cues can be extracted for the users. A linear time-varying (LTV) MPC-based MCA method is designed for the first time in this article to consider the parameters of the hexapod mechanism in the MPC model. The proposed model (LTV MPC-based MCA) is validated using the MATLAB software, and the results depict better motion sensation with more accurate motion signals as compared with those from the existing LTI MPC-based MCA methods.

Meccanica, 2019

In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. U... more In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. Uncertainties that affect systems through any of their states and may not be directly accessed by their controllers. These uncertainties emerge in a system either due to unmodeled dynamics, practical limitations, or external disturbances. Continuum robots possess highly nonlinear dynamic behaviour due to their elastic nature and operate within undefined or congested environments, exposing them to such uncertainties. However, mismatched uncertainties in the continuum robots’ field, are yet to be addressed. Here, we tackle this problem and propose the first robust control for continuum robots that assures its robustness property under mismatched uncertainties. To this end, we first derive the dynamic model for our continuum robot by considering it as an elastic rod and then applying Cosserat rod theory. This will result in a general dynamic model that does not require any design or operative assumption. Next, we design our robust controller utilizing multi-surface sliding mode control, a method capable of handling nonlinear systems under mismatched uncertainties. Finally, we include simulations to validate our controller’s performance.

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012

2010 11th International Conference on Control Automation Robotics & Vision, 2010

In this paper, we propose a systematic solution to the leader-follower consensus of a class of no... more In this paper, we propose a systematic solution to the leader-follower consensus of a class of nonholonomic chained form systems. The control design, which is reminiscent of terminal sliding mode and multi-surface sliding mode control methods, is presented to guarantee the convergence of multiple sliding surfaces, which also implies the convergence of the proposed consensus error function. On these sliding surfaces, the desired leader-follower consensus can be reached for multi-agent network formed by the nonholonomic chained form systems.

2008 10th International Conference on Control, Automation, Robotics and Vision, 2008

This paper is concerned with leader-follower finite-time consensus control of multi-agent network... more This paper is concerned with leader-follower finite-time consensus control of multi-agent networks with input disturbances. Terminal sliding mode control scheme is used to design the distributed control law. A new terminal sliding mode surface is proposed to guarantee finite-time consensus under fixed topology, with the common assumption that the position and the velocity of the active leader is known to

IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2019

The hexapod manipulator is the most common motion platform, which is widely used as a simulation-... more The hexapod manipulator is the most common motion platform, which is widely used as a simulation-based motion platform (SBMP). As the hexapod manipulator has a limited workspace, it is not physically possible to regenerate the real vehicle motion signals using the SBMP. The motion cueing algorithm (MCA) is responsible for regenerating a realistic vehicle motion sensation for the user when the SBMP operates within its physical and dynamical limitations. Recently, model predictive control (MPC) has been introduced to extract the optimal input motion signals while considering the SBMP limitations in the Cartesian coordinate space, which leads to a linear time-invariant (LTI) MPC-based MCA methods. Unfortunately, the existing LTI MPC-based MCA methods are still not able to consider the parameters of the SBMP’s hexapod mechanisms inside their models. In general, the current studies only consider the constraints in the Cartesian coordinate system of the hexapod mechanism, instead of its design parameters. This consideration results in a poor usage of the hexapod workspace due to the conservative assumptions; consequently, the SBMP users do not experience realistic motions. The main contribution of this article is to take the SBMP’s physical limitations into account in the MPC model such that more precise motion cues can be extracted for the users. A linear time-varying (LTV) MPC-based MCA method is designed for the first time in this article to consider the parameters of the hexapod mechanism in the MPC model. The proposed model (LTV MPC-based MCA) is validated using the MATLAB software, and the results depict better motion sensation with more accurate motion signals as compared with those from the existing LTI MPC-based MCA methods.

Meccanica, 2019

In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. U... more In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. Uncertainties that affect systems through any of their states and may not be directly accessed by their controllers. These uncertainties emerge in a system either due to unmodeled dynamics, practical limitations, or external disturbances. Continuum robots possess highly nonlinear dynamic behaviour due to their elastic nature and operate within undefined or congested environments, exposing them to such uncertainties. However, mismatched uncertainties in the continuum robots’ field, are yet to be addressed. Here, we tackle this problem and propose the first robust control for continuum robots that assures its robustness property under mismatched uncertainties. To this end, we first derive the dynamic model for our continuum robot by considering it as an elastic rod and then applying Cosserat rod theory. This will result in a general dynamic model that does not require any design or operative assumption. Next, we design our robust controller utilizing multi-surface sliding mode control, a method capable of handling nonlinear systems under mismatched uncertainties. Finally, we include simulations to validate our controller’s performance.

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013

ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a... more ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a traditional backstepping control (TBSC) and an adaptive backstepping control (ABSC) for a current control and a voltage control scheme in a maglev position control system, respectively. In the ABSC system, an adaptive estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, to solve the trouble of chattering phenomena caused by a sign function in TBSC law in despite of the utilization of a fixed value or an simple adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control with current and voltage control schemes can be verified in experimental results.

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012

This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including ... more This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including an adaptive terminal sliding mode control (ATSMC) and an exact-estimator based terminal sliding mode control (ETSMC) for second-order nonlinear dynamical systems. In the ATSMC system, an adaptive bound estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, an exact estimator is designed for exact estimating system uncertainties to solve the trouble of chattering phenomena caused by a sign function in ATSMC law in despite of the utilization of a fixed value or an adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control schemes can be verified in numerical simulations.

This paper presents a sliding mode control approach for multi-robot formation with collision avoi... more This paper presents a sliding mode control approach for multi-robot formation with collision avoidance. Based on the algebraic graph theory, connections between robots are defined. The formation control with collision avoidance is then solved by a proper design of sliding surface that incorporates potential functions for collision avoidance. The stability of the system is established by using a Lyapunov approach. It is shown that the proposed method makes all robots achieve a specified formation while the collision is avoided. The performance of a system is verified by numerical simulation and experiment result.

2010 11th International Conference on Control Automation Robotics & Vision, 2010

In this paper, we propose a systematic solution to the leader-follower consensus of a class of no... more In this paper, we propose a systematic solution to the leader-follower consensus of a class of nonholonomic chained form systems. The control design, which is reminiscent of terminal sliding mode and multi-surface sliding mode control methods, is presented to guarantee the convergence of multiple sliding surfaces, which also implies the convergence of the proposed consensus error function. On these sliding surfaces, the desired leader-follower consensus can be reached for multi-agent network formed by the nonholonomic chained form systems.

2008 10th International Conference on Control, Automation, Robotics and Vision, 2008

This paper is concerned with leader-follower finite-time consensus control of multi-agent network... more This paper is concerned with leader-follower finite-time consensus control of multi-agent networks with input disturbances. Terminal sliding mode control scheme is used to design the distributed control law. A new terminal sliding mode surface is proposed to guarantee finite-time consensus under fixed topology, with the common assumption that the position and the velocity of the active leader is known to

IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2019

The hexapod manipulator is the most common motion platform, which is widely used as a simulation-... more The hexapod manipulator is the most common motion platform, which is widely used as a simulation-based motion platform (SBMP). As the hexapod manipulator has a limited workspace, it is not physically possible to regenerate the real vehicle motion signals using the SBMP. The motion cueing algorithm (MCA) is responsible for regenerating a realistic vehicle motion sensation for the user when the SBMP operates within its physical and dynamical limitations. Recently, model predictive control (MPC) has been introduced to extract the optimal input motion signals while considering the SBMP limitations in the Cartesian coordinate space, which leads to a linear time-invariant (LTI) MPC-based MCA methods. Unfortunately, the existing LTI MPC-based MCA methods are still not able to consider the parameters of the SBMP’s hexapod mechanisms inside their models. In general, the current studies only consider the constraints in the Cartesian coordinate system of the hexapod mechanism, instead of its design parameters. This consideration results in a poor usage of the hexapod workspace due to the conservative assumptions; consequently, the SBMP users do not experience realistic motions. The main contribution of this article is to take the SBMP’s physical limitations into account in the MPC model such that more precise motion cues can be extracted for the users. A linear time-varying (LTV) MPC-based MCA method is designed for the first time in this article to consider the parameters of the hexapod mechanism in the MPC model. The proposed model (LTV MPC-based MCA) is validated using the MATLAB software, and the results depict better motion sensation with more accurate motion signals as compared with those from the existing LTI MPC-based MCA methods.

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013

ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a... more ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a traditional backstepping control (TBSC) and an adaptive backstepping control (ABSC) for a current control and a voltage control scheme in a maglev position control system, respectively. In the ABSC system, an adaptive estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, to solve the trouble of chattering phenomena caused by a sign function in TBSC law in despite of the utilization of a fixed value or an simple adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control with current and voltage control schemes can be verified in experimental results.

Meccanica, 2019

In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. U... more In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. Uncertainties that affect systems through any of their states and may not be directly accessed by their controllers. These uncertainties emerge in a system either due to unmodeled dynamics, practical limitations, or external disturbances. Continuum robots possess highly nonlinear dynamic behaviour due to their elastic nature and operate within undefined or congested environments, exposing them to such uncertainties. However, mismatched uncertainties in the continuum robots’ field, are yet to be addressed. Here, we tackle this problem and propose the first robust control for continuum robots that assures its robustness property under mismatched uncertainties. To this end, we first derive the dynamic model for our continuum robot by considering it as an elastic rod and then applying Cosserat rod theory. This will result in a general dynamic model that does not require any design or operative assumption. Next, we design our robust controller utilizing multi-surface sliding mode control, a method capable of handling nonlinear systems under mismatched uncertainties. Finally, we include simulations to validate our controller’s performance.

This paper presents a sliding mode control approach for multi-robot formation with collision avoi... more This paper presents a sliding mode control approach for multi-robot formation with collision avoidance. Based on the algebraic graph theory, connections between robots are defined. The formation control with collision avoidance is then solved by a proper design of sliding surface that incorporates potential functions for collision avoidance. The stability of the system is established by using a Lyapunov approach. It is shown that the proposed method makes all robots achieve a specified formation while the collision is avoided. The performance of a system is verified by numerical simulation and experiment result.

2009 4th IEEE Conference on Industrial Electronics and Applications, 2009

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012

This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including ... more This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including an adaptive terminal sliding mode control (ATSMC) and an exact-estimator based terminal sliding mode control (ETSMC) for second-order nonlinear dynamical systems. In the ATSMC system, an adaptive bound estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, an exact estimator is designed for exact estimating system uncertainties to solve the trouble of chattering phenomena caused by a sign function in ATSMC law in despite of the utilization of a fixed value or an adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control schemes can be verified in numerical simulations.

2007 2nd IEEE Conference on Industrial Electronics and Applications, 2007

2007 6th International Conference on Information, Communications & Signal Processing, 2007

IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2019

The hexapod manipulator is the most common motion platform, which is widely used as a simulation-... more The hexapod manipulator is the most common motion platform, which is widely used as a simulation-based motion platform (SBMP). As the hexapod manipulator has a limited workspace, it is not physically possible to regenerate the real vehicle motion signals using the SBMP. The motion cueing algorithm (MCA) is responsible for regenerating a realistic vehicle motion sensation for the user when the SBMP operates within its physical and dynamical limitations. Recently, model predictive control (MPC) has been introduced to extract the optimal input motion signals while considering the SBMP limitations in the Cartesian coordinate space, which leads to a linear time-invariant (LTI) MPC-based MCA methods. Unfortunately, the existing LTI MPC-based MCA methods are still not able to consider the parameters of the SBMP’s hexapod mechanisms inside their models. In general, the current studies only consider the constraints in the Cartesian coordinate system of the hexapod mechanism, instead of its design parameters. This consideration results in a poor usage of the hexapod workspace due to the conservative assumptions; consequently, the SBMP users do not experience realistic motions. The main contribution of this article is to take the SBMP’s physical limitations into account in the MPC model such that more precise motion cues can be extracted for the users. A linear time-varying (LTV) MPC-based MCA method is designed for the first time in this article to consider the parameters of the hexapod mechanism in the MPC model. The proposed model (LTV MPC-based MCA) is validated using the MATLAB software, and the results depict better motion sensation with more accurate motion signals as compared with those from the existing LTI MPC-based MCA methods.

Meccanica, 2019

In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. U... more In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. Uncertainties that affect systems through any of their states and may not be directly accessed by their controllers. These uncertainties emerge in a system either due to unmodeled dynamics, practical limitations, or external disturbances. Continuum robots possess highly nonlinear dynamic behaviour due to their elastic nature and operate within undefined or congested environments, exposing them to such uncertainties. However, mismatched uncertainties in the continuum robots’ field, are yet to be addressed. Here, we tackle this problem and propose the first robust control for continuum robots that assures its robustness property under mismatched uncertainties. To this end, we first derive the dynamic model for our continuum robot by considering it as an elastic rod and then applying Cosserat rod theory. This will result in a general dynamic model that does not require any design or operative assumption. Next, we design our robust controller utilizing multi-surface sliding mode control, a method capable of handling nonlinear systems under mismatched uncertainties. Finally, we include simulations to validate our controller’s performance.

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012

2010 11th International Conference on Control Automation Robotics & Vision, 2010

In this paper, we propose a systematic solution to the leader-follower consensus of a class of no... more In this paper, we propose a systematic solution to the leader-follower consensus of a class of nonholonomic chained form systems. The control design, which is reminiscent of terminal sliding mode and multi-surface sliding mode control methods, is presented to guarantee the convergence of multiple sliding surfaces, which also implies the convergence of the proposed consensus error function. On these sliding surfaces, the desired leader-follower consensus can be reached for multi-agent network formed by the nonholonomic chained form systems.

2008 10th International Conference on Control, Automation, Robotics and Vision, 2008

This paper is concerned with leader-follower finite-time consensus control of multi-agent network... more This paper is concerned with leader-follower finite-time consensus control of multi-agent networks with input disturbances. Terminal sliding mode control scheme is used to design the distributed control law. A new terminal sliding mode surface is proposed to guarantee finite-time consensus under fixed topology, with the common assumption that the position and the velocity of the active leader is known to

IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2019

The hexapod manipulator is the most common motion platform, which is widely used as a simulation-... more The hexapod manipulator is the most common motion platform, which is widely used as a simulation-based motion platform (SBMP). As the hexapod manipulator has a limited workspace, it is not physically possible to regenerate the real vehicle motion signals using the SBMP. The motion cueing algorithm (MCA) is responsible for regenerating a realistic vehicle motion sensation for the user when the SBMP operates within its physical and dynamical limitations. Recently, model predictive control (MPC) has been introduced to extract the optimal input motion signals while considering the SBMP limitations in the Cartesian coordinate space, which leads to a linear time-invariant (LTI) MPC-based MCA methods. Unfortunately, the existing LTI MPC-based MCA methods are still not able to consider the parameters of the SBMP’s hexapod mechanisms inside their models. In general, the current studies only consider the constraints in the Cartesian coordinate system of the hexapod mechanism, instead of its design parameters. This consideration results in a poor usage of the hexapod workspace due to the conservative assumptions; consequently, the SBMP users do not experience realistic motions. The main contribution of this article is to take the SBMP’s physical limitations into account in the MPC model such that more precise motion cues can be extracted for the users. A linear time-varying (LTV) MPC-based MCA method is designed for the first time in this article to consider the parameters of the hexapod mechanism in the MPC model. The proposed model (LTV MPC-based MCA) is validated using the MATLAB software, and the results depict better motion sensation with more accurate motion signals as compared with those from the existing LTI MPC-based MCA methods.

Meccanica, 2019

In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. U... more In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. Uncertainties that affect systems through any of their states and may not be directly accessed by their controllers. These uncertainties emerge in a system either due to unmodeled dynamics, practical limitations, or external disturbances. Continuum robots possess highly nonlinear dynamic behaviour due to their elastic nature and operate within undefined or congested environments, exposing them to such uncertainties. However, mismatched uncertainties in the continuum robots’ field, are yet to be addressed. Here, we tackle this problem and propose the first robust control for continuum robots that assures its robustness property under mismatched uncertainties. To this end, we first derive the dynamic model for our continuum robot by considering it as an elastic rod and then applying Cosserat rod theory. This will result in a general dynamic model that does not require any design or operative assumption. Next, we design our robust controller utilizing multi-surface sliding mode control, a method capable of handling nonlinear systems under mismatched uncertainties. Finally, we include simulations to validate our controller’s performance.

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013

ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a... more ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a traditional backstepping control (TBSC) and an adaptive backstepping control (ABSC) for a current control and a voltage control scheme in a maglev position control system, respectively. In the ABSC system, an adaptive estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, to solve the trouble of chattering phenomena caused by a sign function in TBSC law in despite of the utilization of a fixed value or an simple adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control with current and voltage control schemes can be verified in experimental results.

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012

This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including ... more This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including an adaptive terminal sliding mode control (ATSMC) and an exact-estimator based terminal sliding mode control (ETSMC) for second-order nonlinear dynamical systems. In the ATSMC system, an adaptive bound estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, an exact estimator is designed for exact estimating system uncertainties to solve the trouble of chattering phenomena caused by a sign function in ATSMC law in despite of the utilization of a fixed value or an adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control schemes can be verified in numerical simulations.

This paper presents a sliding mode control approach for multi-robot formation with collision avoi... more This paper presents a sliding mode control approach for multi-robot formation with collision avoidance. Based on the algebraic graph theory, connections between robots are defined. The formation control with collision avoidance is then solved by a proper design of sliding surface that incorporates potential functions for collision avoidance. The stability of the system is established by using a Lyapunov approach. It is shown that the proposed method makes all robots achieve a specified formation while the collision is avoided. The performance of a system is verified by numerical simulation and experiment result.

2010 11th International Conference on Control Automation Robotics & Vision, 2010

In this paper, we propose a systematic solution to the leader-follower consensus of a class of no... more In this paper, we propose a systematic solution to the leader-follower consensus of a class of nonholonomic chained form systems. The control design, which is reminiscent of terminal sliding mode and multi-surface sliding mode control methods, is presented to guarantee the convergence of multiple sliding surfaces, which also implies the convergence of the proposed consensus error function. On these sliding surfaces, the desired leader-follower consensus can be reached for multi-agent network formed by the nonholonomic chained form systems.

2008 10th International Conference on Control, Automation, Robotics and Vision, 2008

This paper is concerned with leader-follower finite-time consensus control of multi-agent network... more This paper is concerned with leader-follower finite-time consensus control of multi-agent networks with input disturbances. Terminal sliding mode control scheme is used to design the distributed control law. A new terminal sliding mode surface is proposed to guarantee finite-time consensus under fixed topology, with the common assumption that the position and the velocity of the active leader is known to

IEEE Transactions on Systems, Man, and Cybernetics: Systems, 2019

The hexapod manipulator is the most common motion platform, which is widely used as a simulation-... more The hexapod manipulator is the most common motion platform, which is widely used as a simulation-based motion platform (SBMP). As the hexapod manipulator has a limited workspace, it is not physically possible to regenerate the real vehicle motion signals using the SBMP. The motion cueing algorithm (MCA) is responsible for regenerating a realistic vehicle motion sensation for the user when the SBMP operates within its physical and dynamical limitations. Recently, model predictive control (MPC) has been introduced to extract the optimal input motion signals while considering the SBMP limitations in the Cartesian coordinate space, which leads to a linear time-invariant (LTI) MPC-based MCA methods. Unfortunately, the existing LTI MPC-based MCA methods are still not able to consider the parameters of the SBMP’s hexapod mechanisms inside their models. In general, the current studies only consider the constraints in the Cartesian coordinate system of the hexapod mechanism, instead of its design parameters. This consideration results in a poor usage of the hexapod workspace due to the conservative assumptions; consequently, the SBMP users do not experience realistic motions. The main contribution of this article is to take the SBMP’s physical limitations into account in the MPC model such that more precise motion cues can be extracted for the users. A linear time-varying (LTV) MPC-based MCA method is designed for the first time in this article to consider the parameters of the hexapod mechanism in the MPC model. The proposed model (LTV MPC-based MCA) is validated using the MATLAB software, and the results depict better motion sensation with more accurate motion signals as compared with those from the existing LTI MPC-based MCA methods.

IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society, 2013

ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a... more ABSTRACT This study mainly focuses on the backstepping control (BSC) strategy design, including a traditional backstepping control (TBSC) and an adaptive backstepping control (ABSC) for a current control and a voltage control scheme in a maglev position control system, respectively. In the ABSC system, an adaptive estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, to solve the trouble of chattering phenomena caused by a sign function in TBSC law in despite of the utilization of a fixed value or an simple adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control with current and voltage control schemes can be verified in experimental results.

Meccanica, 2019

In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. U... more In this paper, we tackle the control problem of continuum robots with mismatched uncertainties. Uncertainties that affect systems through any of their states and may not be directly accessed by their controllers. These uncertainties emerge in a system either due to unmodeled dynamics, practical limitations, or external disturbances. Continuum robots possess highly nonlinear dynamic behaviour due to their elastic nature and operate within undefined or congested environments, exposing them to such uncertainties. However, mismatched uncertainties in the continuum robots’ field, are yet to be addressed. Here, we tackle this problem and propose the first robust control for continuum robots that assures its robustness property under mismatched uncertainties. To this end, we first derive the dynamic model for our continuum robot by considering it as an elastic rod and then applying Cosserat rod theory. This will result in a general dynamic model that does not require any design or operative assumption. Next, we design our robust controller utilizing multi-surface sliding mode control, a method capable of handling nonlinear systems under mismatched uncertainties. Finally, we include simulations to validate our controller’s performance.

This paper presents a sliding mode control approach for multi-robot formation with collision avoi... more This paper presents a sliding mode control approach for multi-robot formation with collision avoidance. Based on the algebraic graph theory, connections between robots are defined. The formation control with collision avoidance is then solved by a proper design of sliding surface that incorporates potential functions for collision avoidance. The stability of the system is established by using a Lyapunov approach. It is shown that the proposed method makes all robots achieve a specified formation while the collision is avoided. The performance of a system is verified by numerical simulation and experiment result.

2009 4th IEEE Conference on Industrial Electronics and Applications, 2009

IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, 2012

This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including ... more This study mainly focuses on the terminal sliding mode control (TSMC) strategy design, including an adaptive terminal sliding mode control (ATSMC) and an exact-estimator based terminal sliding mode control (ETSMC) for second-order nonlinear dynamical systems. In the ATSMC system, an adaptive bound estimation for the lump uncertainty is proposed to ensure the system stability. On the other hand, an exact estimator is designed for exact estimating system uncertainties to solve the trouble of chattering phenomena caused by a sign function in ATSMC law in despite of the utilization of a fixed value or an adaptive tuning algorithm for the lumped uncertainty bound. The effectiveness of the proposed control schemes can be verified in numerical simulations.

2007 2nd IEEE Conference on Industrial Electronics and Applications, 2007

2007 6th International Conference on Information, Communications & Signal Processing, 2007