- Iran, Islamic Republic of
ali moosavian
K. N. Toosi University of Technology, Mechanical Engineering, Faculty Member
- S. Ali A. Moosavian received his BS degree in 1986 from Sharif University of Technology and the MS degree in 1990 fro... moreS. Ali A. Moosavian received his BS degree in 1986 from Sharif University of Technology and the MS degree in 1990 from Tarbiat Modaress University (both in Tehran), and his PhD degree in 1996 from McGill University (Montreal, Canada), all in Mechanical Engineering. He is with the Mechanical Engineering Department at K. N. Toosi University of Technology (Tehran) since 1997, currently as a Professor. He teaches courses in the areas of robotics, dynamics, automatic control, analysis and synthesis of mechanisms. His research interests are in the areas of dynamics modeling, and motion/impedance control of terrestrial and space robotic systems. He has published more than 300 articles in journals and conference proceedings. He is one of the founders of the ARAS Research Center, and the Robotics Society of Iran (RSI).edit
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Model predictive control (MPC) has shown great success for controlling complex systems such as legged robots. However, when closing the loop, the performance and feasibility of the finite horizon optimal control problem solved at each... more
Model predictive control (MPC) has shown great success for controlling complex systems such as legged robots. However, when closing the loop, the performance and feasibility of the finite horizon optimal control problem solved at each control cycle is not guaranteed anymore. This is due to model discrepancies, the effect of low-level controllers, uncertainties and sensor noise. To address these issues, we propose a modified version of a standard MPC approach used in legged locomotion with viability (weak forward invariance) guarantees that ensures the feasibility of the optimal control problem. Moreover, we use past experimental data to find the best cost weights, which measure a combination of performance, constraint satisfaction robustness, or stability (invariance). These interpretable costs measure the trade off between robustness and performance. For this purpose, we use Bayesian optimization (BO) to systematically design experiments that help efficiently collect data to learn ...
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This paper proposes a gait planning approach to reduce the required friction for a biped robot walking on various surfaces. To this end, a humanoid robot with 18 DOF is considered to develop a dynamics model for studying various 3D... more
This paper proposes a gait planning approach to reduce the required friction for a biped robot walking on various surfaces. To this end, a humanoid robot with 18 DOF is considered to develop a dynamics model for studying various 3D manoeuvres. Then, feasible trajectories are developed to alleviate the fluctuations on the upper body to resemble human-like walking. In order to generate feasible walking patterns, not only horizontal interaction moments for the computation of ZMP, but also horizontal forces and vertical moment constraints between the feet and the ground surface are taken into account. Since the pelvis trajectory does drastically affect the walking pattern, the focus will be on generating a smooth motion for the pelvis. This smooth motion is generated based on a desired motion for the robot’s Centre of Mass (COM), which is mapped to the joint space using inverse kinematics. In fact, the proposed approach involves computing a moving ZMP based on a predefined desired COM t...
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Original Research Paper Accuracy and numerical calculation time are the two main challenges of continuum robots dynamics modeling. In fact, the numerical calculation times of exact models are so long, that they are not practical in... more
Original Research Paper Accuracy and numerical calculation time are the two main challenges of continuum robots dynamics modeling. In fact, the numerical calculation times of exact models are so long, that they are not practical in applications such as real-time control. This paper presents a new method for d y n am i c s m o d e li n g o f c o n t i n u u m r o b o t b a c k b on e s. I n t h i s m et h od , t h e ba c k b o n e s h ap e i s considered as an arbitrary number of constant-curvature (circular arc) elements, and the dynamics model is derived using Lagrange energy methods. First, kinetics and kinematics of one element are derived. Then, the robot kinematics is obtained as a series of such elements. Finally, the robot dynamics model is derived using Euler-Lagrange method. This paper is focused on dynamics of the flexible body of continuum robots, and the proposed model is independent of actuation systems. Besides, the numerical singularity of the constant-curvature eleme...
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—Regarding robot interaction with moving objects and the necessity for robot controller to react in a timely manner having the objects current position, finding an efficient positioning method has always been a challenge. As ball and... more
—Regarding robot interaction with moving objects and the necessity for robot controller to react in a timely manner having the objects current position, finding an efficient positioning method has always been a challenge. As ball and plate system is considered to be a standard experimental system in control laboratories. The system is consisted of the following pieces: a horizontal plate which gets tilted along each horizontal axes. The ball, which is located on the plate; is controlled by the system in a way to be placed in any point on the plate. In fact, the ball and plate system is an extension of the classical ball on beam experiment that is often used to study various types of control and stability problems.
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the presence of an unknown environment, have been proposed [8]. The Object Impedance Control (OIC), an extension ofimpedance control, has been developed for multiple roboticarms manipulating a common object [9]. The OIC enforces... more
the presence of an unknown environment, have been proposed [8]. The Object Impedance Control (OIC), an extension ofimpedance control, has been developed for multiple roboticarms manipulating a common object [9]. The OIC enforces adesignated impedance not of an individual manipulator endpoint, but of the manipulated object itself. A combination offeedforwardand feedback controls is employed to make theobject behave like a reference impedance. It has been realizedthat applying the OIC to manipulation of a flexible ...
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SUMMARY In this study, a gait optimization routine is developed to generate walking patterns which demand the lowest friction forces for implementation. The aim of this research is to fully address the question “which walking pattern... more
SUMMARY In this study, a gait optimization routine is developed to generate walking patterns which demand the lowest friction forces for implementation. The aim of this research is to fully address the question “which walking pattern demands the lowest coefficient of friction amongst all feasible patterns?”. To this end, first, the kinematic structure of the considered 31 DOF (Degrees of Freedom) humanoid robot is investigated and a closed-form dynamics model for its lower-body is developed. Then, the medium through which the walking pattern generation is conducted is presented. In this medium, after designing trajectories for the feet and the pelvis, the joint space variables are obtained, using the inverse kinematics. Finally, by employing a genetic algorithm (GA), an optimization process is conducted to generate walking patterns with the minimum Required Coefficient Of Friction (RCOF). Six parameters are adopted to parameterize the pelvis trajectory and are exploited as the desig...
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ABSTRACT In this paper, the optimal formation of a team of wheeled robot is dealt with for manipulating a common object. The robotic team has been commanded to transport the object from an initial pose along a specified path to a terminal... more
ABSTRACT In this paper, the optimal formation of a team of wheeled robot is dealt with for manipulating a common object. The robotic team has been commanded to transport the object from an initial pose along a specified path to a terminal pose. To this end, a proper cost function encompassing various aspects will be established and the grasping points of the object will be then determined employing various numerical optimization techniques such as Simulated Annealing, Genetic Algorithm and Particle Swarm Optimization. Finally, the team is controlled using a virtual structure-based approach and multiple-impedance-control strategy so as the obtained optimal formation can be realized.
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Abstract - The mobility requirements on a rough terrain make a suspended wheeled mobile robot (SWMR) with multiple dexterous manipulators an appropriate choice. In this study, dynamics and stability appraisal of such systems will be... more
Abstract - The mobility requirements on a rough terrain make a suspended wheeled mobile robot (SWMR) with multiple dexterous manipulators an appropriate choice. In this study, dynamics and stability appraisal of such systems will be discussed. First, based on Newton-Euler's ...
Research Interests: Mechatronics, Vehicle Dynamics, Stability, Mobile Robots, Rough Terrain, and 12 moreWheeled Mobile Robot, Foot, Rigid Body, Three Dimensional, Fuzzy-Model-Based Control, Dynamic Model of WSN, Object Manipulation, Postural Stability, Simulation Model, Degree of Freedom, Spatial Model, and dynamic model
Abstract-The mobility requirements on a rough terrain make a suspended wheeled mobile robot (SWMR) with multiple dexterous manipulators an appropriate choice. In this study, dynamics modeling and stability appraisal of SWMRs will be... more
Abstract-The mobility requirements on a rough terrain make a suspended wheeled mobile robot (SWMR) with multiple dexterous manipulators an appropriate choice. In this study, dynamics modeling and stability appraisal of SWMRs will be discussed. First, based on Newton-...
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The concept of two-wheeled mobile manipulator (TWMM) has been proposed for its significant advantage due to high maneuverability particularly in confined internal spaces. However, its unbalanced structure imposes restrictions for... more
The concept of two-wheeled mobile manipulator (TWMM) has been proposed for its significant advantage due to high maneuverability particularly in confined internal spaces. However, its unbalanced structure imposes restrictions for widespread application. Note that the nonholonomic property of a TWMM makes its control a more challenging task. In this paper, a new stabilization mechanism of TWMM is presented, and a new control method based on dynamical balancing algorithm is proposed that could effectively resolve those restrictions. To this end, a reaction wheel is considered to control the position of center of gravity (COG), leading to a smoother motion of the robot manipulator. To make the robot be able to manipulate an object, a double inverted pendulum model (DIPM) is considered as a simplified model of the system. DIPM dynamics is used to identify and simplify the dynamics of TWMM and subsequently a supervisory control is employed to stabilize the robot via its COG position. Thi...
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The simplicity of Transpose Jacobian (TJ) control is a significant characteristic of this algorithm for controlling robotic manipulators. Nevertheless, a poor performance may result in tracking of fast trajectories, since it is not... more
The simplicity of Transpose Jacobian (TJ) control is a significant characteristic of this algorithm for controlling robotic manipulators. Nevertheless, a poor performance may result in tracking of fast trajectories, since it is not dynamics-based. Use of high gains can deteriorate performance seriously in the presence of feedback measurement noise. Another drawback is that there is no prescribed method of selecting
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Control of the humanoid robots requires appropriate gait planning that satisfies stable walking. In this study, a Modified Transpose Jacobian (MTJ) control algorithm for object manipulation by two humanoid robots is developed. Such... more
Control of the humanoid robots requires appropriate gait planning that satisfies stable walking. In this study, a Modified Transpose Jacobian (MTJ) control algorithm for object manipulation by two humanoid robots is developed. Such cooperative humanoid robots may typically get employed in hazardous situation and industrial applications. In the present paper, a high performance and robust controller was developed for the
Research Interests: Motion control, Robust control, Path planning, Mobile Robots, Gait Analysis, and 15 moreHumanoid robots, Feedback, Legged Locomotion, Industrial Application, Mathematical Model, High performance, Trajectory Tracking, Humanoid robot, Path Planning, Boolean Satisfiability, Feedback Linearization, Object Manipulation, Simulation Software, Control Algorithm, and dynamic model
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... 10. J. Kim, WK Chung, Y. Youm, & BH Lee, Real-time ZMP compensation method using null motion for mobile manipulators, Proc. ... 23. VA Sujan & S. Dubowsky, An optimal information method for mobile manipulator... more
... 10. J. Kim, WK Chung, Y. Youm, & BH Lee, Real-time ZMP compensation method using null motion for mobile manipulators, Proc. ... 23. VA Sujan & S. Dubowsky, An optimal information method for mobile manipulator dynamic parameter identification, IEEE/ASME Transactions on ...
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Proceedings of the 2004 EEE International Conference on Control Applications Taipei, Taiwan, September 2-4,2004 ... Minimum-Time Optimal Control of Flexible Spacecraft ... Asghar Ebrahimi' , S. Ali A. Moosaviad, Mehran... more
Proceedings of the 2004 EEE International Conference on Control Applications Taipei, Taiwan, September 2-4,2004 ... Minimum-Time Optimal Control of Flexible Spacecraft ... Asghar Ebrahimi' , S. Ali A. Moosaviad, Mehran Mirshams' ... 'Applied Science and Research ...
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SUMMARYControl of rigid–flexible multi-body systems in space, during cooperative manipulation tasks, is studied in this paper. During such tasks, flexible members such as solar panels may vibrate. These vibrations in turn can lead to... more
SUMMARYControl of rigid–flexible multi-body systems in space, during cooperative manipulation tasks, is studied in this paper. During such tasks, flexible members such as solar panels may vibrate. These vibrations in turn can lead to oscillatory disturbing forces on other subsystems, and consequently may produce significant errors in the position of operating end-effectors of cooperative arms. Therefore, to design and implement efficient model-based controllers for such complicated nonlinear systems, deriving an accurate dynamics model is required. On the other hand, due to practical limitations and real-time implementation, such models should demand fairly low computational complexity. In this paper, a precise dynamics model is derived by virtually partitioning the system into two rigid and flexible portions. These two portions will be assembled together to generate a proper model for controller design. Then, an adaptive hybrid suppression control (AHSC) algorithm is developed base...