Which impedance strategy is the most effective for cooperative object manipulation?

2017 ◽  
Vol 44 (2) ◽  
pp. 198-209 ◽  
Author(s):  
Payam Zarafshan ◽  
Reza Larimi ◽  
S. Ali A. Moosavian ◽  
Bruno Siciliano
Keyword(s):  
Conceptual Model ◽  
Degrees Of Freedom ◽  
Impedance Control ◽  
Object Manipulation ◽  
Robotic System ◽  
Control Algorithms ◽  
Practical Implementation ◽  
Content Type ◽  
Manipulation Task ◽  
Cooperative Object Manipulation

Purpose The purpose of this paper is to present a comparison study of cooperative object manipulation control algorithms. To this end, a full comprehensive survey of the existing control algorithms in this field is presented. Design/methodology/approach Cooperative manipulation occurs when manipulators are mechanically coupled to the object being manipulated, and the manipulators may not be treated as an isolated system. The most important and basic impedance control (IC) strategies for an assumed cooperative object manipulation task are the Augmented Object Model (AOM) control and the multiple impedance control (MIC) which are found based on the IC, where the former is designed based on the object movement, and the latter is designed based on the whole robot movement. Thus, the basis of these two algorithms are fully studied. Findings The results are fully analyzed, and it is practically verified that the MIC algorithm has the better performance. In fact, the results reveal that the MIC system could successfully perform the object manipulation task, as opposed to the AOM controller: for the same controller gains, the MIC strategy showed better performance than the AOM strategy. This means that because there is no control on the robot base with the AOM algorithm, the object manipulation task cannot be satisfactorily performed whenever the desired path is not within the robot work space. On the other hand, with the MIC algorithm, satisfactory object manipulation is achieved for a mobile robotic system in which the robot base, the manipulator endpoints and the manipulated object shall be moved. Practical implications A simple conceptual model for cooperative object manipulation is considered, and a suitable setup is designed for practical implementation of the two ICs. Originality/value The basis of these two aspects or these two algorithms is fully studied and compared which is the foundation of this paper. For this purpose, a case study is considered, in which a space free-flying robotic system, which contains two 2-degrees of freedom planar cooperative manipulators, is simulated to manipulate an object using the above control strategies. The system also includes a rotating antenna and camera as its third and fourth arm. Finally, a simple conceptual model for cooperative object manipulation is considered, and a suitable setup is designed for practical implementation of the two ICs.

Cooperation of robotic manipulators using non‐model‐based multiple impedance control

2008 ◽  
Vol 35 (6) ◽  
pp. 549-558 ◽  
Author(s):  
S. Ali A. Moosavian ◽  
Hadi R. Ashtiani
Keyword(s):  
Error Analysis ◽  
Impedance Control ◽  
Object Manipulation ◽  
Tracking Performance ◽  
Content Type ◽  
Model Based ◽  
On Line ◽  
Cooperating Manipulators ◽  
Manipulation Task ◽  
Practical Implications

PurposeThe aim of this paper is to present the non‐model‐based multiple impedance control (NMIC) law for object manipulation tasks, which can be implemented with reasonable limited on‐line computations.Design/methodology/approachThe multiple impedance control (MIC) is a model‐based algorithm that enforces a designated impedance on all cooperating manipulators, and the manipulated object itself. In this paper, the MIC law is modified to be implemented without using system dynamics. Therefore, this modified MIC law is a quick and more realistic algorithm for implementation in cooperating robotic systems, and so is called NMIC. Developing the NMIC law, error analysis shows that under the NMIC law all participating manipulators, and the manipulated object exhibit the same designated impedance behavior. Next, the proposed NMIC law is applied on an object manipulation task with three cooperating PUMA 560 manipulators while two of them are equipped with a remote compliant centre.FindingsDeveloping the NMIC law, error analysis shows that under the NMIC law all participating manipulators, and the manipulated object exhibit the same designated impedance behavior. The obtained results show good tracking performance even in the presence of impacts due to contact with an obstacle, and also system flexibility.Practical implicationsThe obtained results show good tracking performance even in the presence of impacts due to contact with an obstacle, and also system flexibility. These results reveal the merits of NMIC law as a non‐model‐based algorithm for object manipulation tasks, which can be implemented with reasonable limited on‐line computations.Originality/valueThe proposed NMIC law is applied on an object manipulation task with three cooperating PUMA 560 manipulators while two of them are equipped with a remote compliant centre.

scholarly journals Cooperative Object Manipulation by a Space Robot with Flexible Appendages

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
P. Zarafshan ◽  
S. Ali A. Moosavian
Keyword(s):  
Multibody Systems ◽  
Control Algorithm ◽  
Object Manipulation ◽  
Robotic System ◽  
Flexible Multibody Systems ◽  
Solar Panels ◽  
Manipulation Task ◽  
End Effectors ◽  
Cooperative Object Manipulation ◽  
Flexible Appendages

Modelling and control of rigid-flexible multibody systems is studied in this paper. As a specified application, a space robotic system with flexible appendages during a cooperative object manipulation task is considered. This robotic system necessitates delicate force exertion by several end-effectors to move an object along a desired path. During such maneuvers, flexible appendages like solar panels may get stimulated and vibrate. This vibrating motion will cause some oscillatory disturbing forces on the spacecraft, which in turn produces error in the motion of the end-effectors of the cooperative manipulating arms. In addition, vibration control of these flexible members to protect them from fracture is another challenging problem in an object manipulation task for the stated systems. Therefore, the multiple impedance control algorithm is extended to perform an object manipulation task by such complicated rigid-flexible multibody systems. This extension in the control algorithm considers the modification term which compensates the disturbing forces due to vibrating motion of flexible appendages. Finally, a space free-flying robotic system which contains two 2-DOF planar cooperative manipulators, appended with two highly flexible solar panels, is simulated. Obtained results reveal the merits of the developed model-based controller which will be discussed.

Microsurgical robotic system for the deep surgical field: development of a prototype and feasibility studies in animal and cadaveric models

2005 ◽  
Vol 103 (2) ◽  
pp. 320-327 ◽  
Author(s):  
Akio Morita ◽  
Shigeo Sora ◽  
Mamoru Mitsuishi ◽  
Shinichi Warisawa ◽  
Katopo Suruman ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Control Unit ◽  
Feasibility Studies ◽  
Robotic System ◽  
Content Type ◽  
Field Development ◽  
Six Degrees Of Freedom ◽  
Surgical Field ◽  
Robotic Instruments ◽  
Fine Print

Object. To enhance the surgeon's dexterity and maneuverability in the deep surgical field, the authors developed a master—slave microsurgical robotic system. This concept and the results of preliminary experiments are reported in this paper. Methods. The system has a master control unit, which conveys motion commands in six degrees of freedom (X, Y, and Z directions; rotation; tip flexion; and grasping) to two arms. The slave manipulator has a hanging base with an additional six degrees of freedom; it holds a motorized operating unit with two manipulators (5 mm in diameter, 18 cm in length). The accuracy of the prototype in both shallow and deep surgical fields was compared with routine freehand microsurgery. Closure of a partial arteriotomy and complete end-to-end anastomosis of the carotid artery (CA) in the deep operative field were performed in 20 Wistar rats. Three routine surgical procedures were also performed in cadavers. The accuracy of pointing with the nondominant hand in the deep surgical field was significantly improved through the use of robotics. The authors successfully closed the partial arteriotomy and completely anastomosed the rat CAs in the deep surgical field. The time needed for stitching was significantly shortened over the course of the first 10 rat experiments. The robotic instruments also moved satisfactorily in cadavers, but the manipulators still need to be smaller to fit into the narrow intracranial space. Conclusions. Computer-controlled surgical manipulation will be an important tool for neurosurgery, and preliminary experiments involving this robotic system demonstrate its promising maneuverability.

Optimal grasp force for robotic grasping and in-hand manipulation with impedance control

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaoqing Li ◽  
Ziyu Chen ◽  
Chao Ma
Keyword(s):  
Degrees Of Freedom ◽  
Impedance Control ◽  
Difficult Problem ◽  
Contact Forces ◽  
Design Parameters ◽  
Robotic Hand ◽  
Content Type ◽  
Cone Constraint ◽  
Grasp Force ◽  
Grasp Quality

Purpose The purpose of this paper is to achieve stable grasping and dexterous in-hand manipulation, the control of the multi-fingered robotic hand is a difficult problem as the hand has many degrees of freedom with various grasp configurations. Design/methodology/approach To achieve this goal, a novel object-level impedance control framework with optimized grasp force and grasp quality is proposed for multi-fingered robotic hand grasping and in-hand manipulation. The minimal grasp force optimization aims to achieve stable grasping satisfying friction cone constraint while keeping appropriate contact forces without damage to the object. With the optimized grasp quality function, optimal grasp quality can be obtained by dynamically sliding on the object from initial grasp configuration to final grasp configuration. By the proposed controller, the in-hand manipulation of the grasped object can be achieved with compliance to the environment force. The control performance of the closed-loop robotic system is guaranteed by appropriately choosing the design parameters as proved by a Lyapunove function. Findings Simulations are conducted to validate the efficiency and performance of the proposed controller with a three-fingered robotic hand. Originality/value This paper presents a method for robotic optimal grasping and in-hand manipulation with a compliant controller. It may inspire other related researchers and has great potential for practical usage in a widespread of robot applications.

A robotic system with reinforcement learning for lower extremity hemiparesis rehabilitation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiajun Xu ◽  
Linsen Xu ◽  
Gaoxin Cheng ◽  
Jia Shi ◽  
Jinfu Liu ◽  
...  
Keyword(s):  
Reinforcement Learning ◽  
Lower Extremity ◽  
Muscle Activation ◽  
High Efficiency ◽  
Impedance Control ◽  
Robotic System ◽  
Mirror Therapy ◽  
Content Type ◽  
Model Reference Adaptive ◽  
Rehabilitation Exercise

Purpose This paper aims to propose a bilateral robotic system for lower extremity hemiparesis rehabilitation. The hemiplegic patients can complete rehabilitation exercise voluntarily with the assistance of the robot. The reinforcement learning is included in the robot control system, enhancing the muscle activation of the impaired limbs (ILs) efficiently with ensuring the patients’ safety. Design/methodology/approach A bilateral leader–follower robotic system is constructed for lower extremity hemiparesis rehabilitation, where the leader robot interacts with the healthy limb (HL) and the follow robot is worn by the IL. The therapeutic training is transferred from the HL to the IL with the assistance of the robot, and the IL follows the motion trajectory prescribed by the HL, which is called the mirror therapy. The model reference adaptive impedance control is used for the leader robot, and the reinforcement learning controller is designed for the follower robot. The reinforcement learning aims to increase the muscle activation of the IL and ensure that its motion can be mastered by the HL for safety. An asynchronous algorithm is designed by improving experience relay to run in parallel on multiple robotic platforms to reduce learning time. Findings Through clinical tests, the lower extremity hemiplegic patients can rehabilitate with high efficiency using the robotic system. Also, the proposed scheme outperforms other state-of-the-art methods in tracking performance, muscle activation, learning efficiency and rehabilitation efficacy. Originality/value Using the aimed robotic system, the lower extremity hemiplegic patients with different movement abilities can obtain better rehabilitation efficacy.

The value of project management to competitiveness: key factors from a holistic and practical perspective

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Cláudia Sousa Silva ◽  
Cláudia Pereira ◽  
José Magano
Keyword(s):  
Project Management ◽  
Literature Review ◽  
Conceptual Model ◽  
Business Success ◽  
Practical Implementation ◽  
Real Problem ◽  
Key Factors ◽  
Content Type ◽  
Holistic Perspective ◽  
Practical Implications

PurposeThe contribution of project success and the organisation's efficiency is consensual in the literature. However, the value of project management (PM) brings to the organisation's effectiveness through the alignment with strategy, contributing to its competitiveness and business success, is yet little explored. This study addresses the literature gap that concerns the relationship between PM and the organisation's competitiveness, proposing a holistic conceptual model to understand of how PM brings value to the organisation. This work also aims to demonstrate the practical implications of theoretical contributions to the value of PM. For this, a detailed action research (AR) was planned to show how researchers and practitioners could work and collaborate in a real problem and prove the AR approach's adequacy to the PM field.Design/methodology/approachThe methodology starts with a systematic literature review (SLR), followed by content analysis to develop a conceptual model of PM's value. To validate the theoretical constructs and transfer the results to real context, an AR plan is then carried out to support a specific PM problem presented by an automotive industry company.FindingsThe results have theoretical and practical implications. An original conceptual model is developed–the value of PM: Key factors–defending a multidimensional and holistic perspective to understand the PM's value. A set of key factors was identified, structured, interrelated and exemplified their practical implementation in a single company. In addition to the technical key factors identified in the literature review, the AR plan unveils crucial social aspects to improve PM's value, such as leadership, strong communication and open processes. This work shows the central role of PM methodologies in integrating and interconnecting the key factors, emphasizing the projects' strategic level.Research limitations/implicationsThe present work was developed in a specific and particular organisational context and industry.Practical implicationsThe AR plan presents a company's original programme–Hyper Competitiveness (HC) Temple–implemented in an automotive company. Project management professionals could understand how this company implemented each key factor, defended in a conceptual model and lead the project's results to the business value.Originality/valueThe research originality lies in rethinking PM's value to organisations from a holistic perspective: multi-dimensional, temporal, life cycle, multi-organisational, pointing out a set of technical and social key factors.

System identification of flybar-less rotorcraft UAV

2020 ◽  
Vol 92 (10) ◽  
pp. 1483-1493
Author(s):  
Khadeeja Nusrath T.K. ◽  
Lulu V.P. ◽  
Jatinder Singh
Keyword(s):  
Stability Analysis ◽  
System Identification ◽  
Degrees Of Freedom ◽  
Autonomous Vehicle ◽  
Model Identification ◽  
Control Algorithms ◽  
Small Scale ◽  
Content Type ◽  
Statistical Measures ◽  
Instrumented Vehicle

Purpose This paper aims to build an accurate mathematical model which is necessary for control design and attitude estimation of a miniature unmanned rotorcraft and its subsequent conversion to an autonomous vehicle. Design/methodology/approach Frequency-domain system identification of a small-size flybar-less remote controlled helicopter is carried out based on the input–output data collected from flight tests of the instrumented vehicle. A complete six degrees of freedom quasi-steady dynamic model is derived for hover and cruise flight conditions. Findings The veracity of the developed model is ascertained by comparing the predicted model responses to the actual responses from flight experiments and from statistical measures. Dynamic stability analysis of the vehicle is carried out using eigenvalues and eigenvectors. The identified model represents the vehicle dynamics very well in the frequency range of interest. Research limitations/implications The model needs to be augmented with additional terms to represent the high-frequency dynamics of the vehicle. Practical implications Control algorithms developed using the first principles model can be easily reconfigured using the identified model, because the model structure is not altered during identification. Originality/value This paper gives a practical solution for model identification and stability analysis of a small-scale flybar-less helicopter. The estimated model can be easily used in developing control algorithms.

Force and motion control of a tendon-driven hand exoskeleton actuated by shape memory alloys

2018 ◽  
Vol 45 (5) ◽  
pp. 623-633 ◽  
Author(s):  
Saber Kazeminasab ◽  
Alireza Hadi ◽  
Khalil Alipour ◽  
Mohammad Elahinia
Keyword(s):  
Shape Memory ◽  
Object Manipulation ◽  
Control Algorithms ◽  
Content Type ◽  
Hand Motion ◽  
Sma Actuators ◽  
Force And Motion ◽  
Grasping Force ◽  
Hand Exoskeleton ◽  
Gripping Force

Purpose Many people suffer from injuries related to their hand. This research aims to focus on the improvement of the previously developed smart glove by using position and force control algorithms. The new smart glove may be used for both physiotherapy and assistance. Design/methodology/approach The proposed robot uses shape memory alloy (SMA) actuators coupled to an under-actuated tendon-driven mechanism. The proposed device, which is presented as a wearable glove attached to an actuation module, is capable of exerting extremely high forces to grasp objects in various hand configurations. The device’s performance is studied in physiotherapy and object manipulation tasks. In the physiotherapy mode, hand motion frequency is controlled, whereas the grasping force is controlled in the object manipulation mode. To simulate the proposed system behavior, the kinematic and dynamic equations of the proposed system have been derived. Findings The achieved results verify that the system is suitable to be used as part of a rehabilitation device in which it can flex and extend fingers with accurate trajectories and grasp objects efficiently. Specifically, it will be shown that using six SMA wires with the diameter of 0.25 mm, the proposed robot can provide 45 N gripping force for the patients. Originality/value The proposed robot uses SMA actuators and an under-actuated tendon-driven mechanism. The resulted robotic system, which is presented as a wearable glove attached to an actuation module, is capable of exerting extremely high force levels to grasp objects in various hand configurations. It is shown that the motion and exerted force of the robot may be controlled effectively in practice.

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