Resolved-acceleration control of robot manipulators: A critical review with experiments

Robotica ◽  
1998 ◽  
Vol 16 (5) ◽  
pp. 565-573 ◽  
Author(s):  
Fabrizio Caccavale ◽  
Ciro Natale ◽  
Bruno Siciliano ◽  
Luigi Villani
Keyword(s):  
Critical Review ◽  
Robot Manipulators ◽  
Industrial Robot ◽  
Practical Implementation ◽  
Euler Angles ◽  
Acceleration Technique ◽  
Feedback Scheme ◽  
Resolved Acceleration Control ◽  
Control Schemes ◽  
The Stability

The goal of this paper is to provide a critical review of the well-known resolved-acceleration technique for the tracking control problem of robot manipulators in the task space. Various control schemes are surveyed and classified according to the type of end-effector orientation error; namely, those based on Euler angles feedback, quaternion feedback, and angle/axis feedback. In addition to the assessed schemes in the literature, an alternative Euler angles feedback scheme is proposed which shows an advantage in terms of avoidance of representation singularities. An insight into the features of each scheme is given, with special concern to the stability properties of those schemes leading to nonlinear closed-loop dynamic equations. A comparison is carried out in terms of computational burden. Experiments on an industrial robot with open control architecture have been carried out, and the tracking performance of the resolved-acceleration control schemes in a case study involving the occurrence of a representation singularity is evaluated. The pros and cons of each scheme are evidenced in a final discussion focused on practical implementation issues.

Theory and Experiments on the Compliance Control of Redundant Robot Manipulators

1990 ◽  
Vol 112 (4) ◽  
pp. 653-660 ◽  
Author(s):  
H. Kazerooni ◽  
K. G. Bouklas ◽  
J. Guo
Keyword(s):  
Degrees Of Freedom ◽  
Control Method ◽  
Robot Manipulators ◽  
Industrial Robot ◽  
Redundant Robot ◽  
Control Approach ◽  
Six Degrees Of Freedom ◽  
The Stability ◽  
Control Methodology ◽  
Theory And Experiments

This work presents a control methodology for compliant motion in redundant robot manipulators. This control approach takes advantage of the redundancy in the robot’s degrees of freedom: while a maximum six degrees of freedom of the robot control the robot’s endpoint position, the remaining degrees of freedom impose an appropriate force on the environment. To verify the applicability of this control method, an active end-effector is mounted on an industrial robot to generate redundancy in the degrees of freedom. A set of experiments are described to demonstrate the use of this control method in constrained maneuvers. The stability of the robot and the environment is analyzed.

Adaptive Control of Robot Manipulators Including Motor Dynamics

1995 ◽  
Vol 209 (3) ◽  
pp. 207-217
Author(s):  
H Yu ◽  
S Lloyd
Keyword(s):  
Adaptive Control ◽  
Control Structure ◽  
Robot Manipulators ◽  
Control Law ◽  
Task Space ◽  
Control Scheme ◽  
Control Schemes ◽  
The Stability ◽  
Adaptive Control Law ◽  
Motor Dynamics

An adaptive control scheme for robot manipulators including motor dynamics is proposed in this paper. The proposed scheme avoids the assumption that the values of motor parameters are known which is required in reference (13). An exponential control law is first developed under the assumption of no uncertainty. This forms a controller structure for the adaptive control. Using this control structure, a full-order adaptive control law is proposed to overcome parameter uncertainty for both robot link and motor. The stability analysis is in the Lyapunov stability sense. The method is further extended to the task space. Extensive simulations are performed to compare the different control schemes.

Stable Calibrations of Six-DOF Serial Robots by Using Identification Models with Equalized Singular Values

Robotica ◽  
2021 ◽  
pp. 1-22
Author(s):  
Zhouxiang Jiang ◽  
Min Huang
Keyword(s):  
Industrial Robot ◽  
Singular Values ◽  
Calibration Method ◽  
Identification Accuracy ◽  
Condition Numbers ◽  
Measurement Instruments ◽  
Unknown Parameters ◽  
Calibration Methods ◽  
Six Dof ◽  
The Stability

SUMMARY In typical calibration methods (kinematic or non-kinematic) for serial industrial robot, though measurement instruments with high resolutions are adopted, measurement configurations are optimized, and redundant parameters are eliminated from identification model, calibration accuracy is still limited under measurement noise. This might be because huge gaps still exist among the singular values of typical identification Jacobians, thereby causing the identification models ill conditioned. This paper addresses such problem by using new identification models established in two steps. First, the typical models are divided into the submodels with truncated singular values. In this way, the unknown parameters corresponding to the abnormal singular values are removed, thereby reducing the condition numbers of the new submodels. However, these models might still be ill conditioned. Therefore, the second step is to further centralize the singular values of each submodel by using a matrix balance method. Afterward, all submodels are well conditioned and obtain much higher observability indices compared with those of typical models. Simulation results indicate that significant improvements in the stability of identification results and the identifiability of unknown parameters are acquired by using the new identification submodels. Experimental results indicate that the proposed calibration method increases the identification accuracy without incurring additional hardware setup costs to the typical calibration method.

A computationally efficient adaptive robust control scheme for a quad-rotor transporting cable-suspended payloads

2021 ◽  
pp. 095441002110136
Author(s):  
Nasim Ullah ◽  
Irfan Sami ◽  
Wang Shaoping ◽  
Hamid Mukhtar ◽  
Xingjian Wang ◽  
...  
Keyword(s):  
Robust Control ◽  
Fractional Order ◽  
Sliding Mode ◽  
Adaptive Robust Control ◽  
Computationally Efficient ◽  
Control Scheme ◽  
Control Schemes ◽  
Adaptive Laws ◽  
Unknown Disturbances ◽  
The Stability

This article proposes a computationally efficient adaptive robust control scheme for a quad-rotor with cable-suspended payloads. Motion of payload introduces unknown disturbances that affect the performance of the quad-rotor controlled with conventional schemes, thus novel adaptive robust controllers with both integer- and fractional-order dynamics are proposed for the trajectory tracking of quad-rotor with cable-suspended payload. The disturbances acting on quad-rotor due to the payload motion are estimated by utilizing adaptive laws derived from integer- and fractional-order Lyapunov functions. The stability of the proposed control systems is guaranteed using integer- and fractional-order Lyapunov theorems. Overall, three variants of the control schemes, namely adaptive fractional-order sliding mode (AFSMC), adaptive sliding mode (ASMC), and classical Sliding mode controllers (SMC)s) are tested using processor in the loop experiments, and based on the two performance indicators, namely robustness and computational resource utilization, the best control scheme is evaluated. From the results presented, it is verified that ASMC scheme exhibits comparable robustness as of SMC and AFSMC, while it utilizes less sources as compared to AFSMC.

New Methodology for the Determination of the Vertical Center of Gravity of In-Service Semisubmersibles: Proposal and Numerical Assessment

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ivan N. Porciuncula ◽  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança
Keyword(s):  
Accurate Determination ◽  
Center Of Gravity ◽  
Practical Implementation ◽  
Numerical Assessment ◽  
Neutral Equilibrium ◽  
Inclination Angles ◽  
Numerical Tools ◽  
The Stability ◽  
Metacentric Height

Along its lifetime, an offshore unit is subjected to several equipment interventions. These modifications may include large conversions in loco that usually are not adequately documented. Hence, the accurate determination of the platform's center of gravity (KG) is not possible. For vessels with low metacentric height (GM), such as semisubmersibles, Classification Societies penalize the platform's KG, inhibiting the installation of new equipment until an accurate measurement of KG is provided, i.e., until an updated inclining test is performed. For an operating semisubmersible, the execution of this type of test is not an alternative because it implies in removing the vessel from its in-service location to sheltered waters. Relatively recently, some methods have been proposed for the estimation of KG for in-service vessels. However, as all of the methods depend on accurate measurements of inclination angles and, eventually, on numerical tools for the simulation of vessel dynamics onboard, they are not straightforward for practical implementation. The objective of the paper is to present a practical methodology for the experimental determination of KG, without the need of accurate measurements of inclinations and/or complex numerical simulations, but based on actual operations that can be performed onboard. Indeed, the proposed methodology relies on the search, identification, and execution of a neutral equilibrium condition where, for instance, KG = KM. The method is exemplified using actual data of a typical semisubmersible. The paper also numerically explores and discusses the stability of the platform under various conditions with unstable initial GM, as well as the effect of mooring and risers.

scholarly journals PRACTICAL IMPLEMENTATION OF THE MODEL OF FORMATION OF CADETS' READINESS TO ENSURE INFORMATION SECURITY IN PROFESSIONAL ACTIVITIES

2021 ◽  
Vol 1 ◽  
pp. 119-129
Author(s):  
Dmitry Dvoretsky ◽  
Natalia Kolesnikova ◽  
Oksana Makarkina ◽  
Kira Lagvilava
Keyword(s):  
Information Systems ◽  
Information Security ◽  
Information Technologies ◽  
The State ◽  
Practical Implementation ◽  
Positive Trend ◽  
Pedagogical Tools ◽  
Professional Activities ◽  
Security Issues ◽  
The Stability

The mass introduction of information technologies in the activities of state structures has made it possible to transfer the efficiency of their functioning to a qualitatively new level. Unfortunately, as a means of action, they have characteristic vulnerabilities and can be used not only for good, but also for harm. For the state, as a guarantor of the stability of a civilized society, the issue of ensuring the security of information processing is particularly important. Despite the automation of many information processes, the most vulnerable link in the work of information systems remains a person. A person acts as an operator of information systems and a consumer of information. The entire service process depends on the competence of the operator and the quality of his perception. There are areas of government activity where the cost of error is particularly high. These include ensuring the life and health of citizens, protecting public order and the state system, and ensuring territorial integrity. The specifics of the spheres must be taken into account when ensuring the security of information. This study concerns official activities that are provided by paramilitary groups. Currently, there is a discrepancy in the level of competence of new personnel in the first months of service. The author traces the shortcomings of general and special professional qualities in the field of information security. The purpose of the study is to substantiate certain pedagogical means of forming cadets ' readiness to ensure information security. As forms of theoretical knowledge, we will use the traditional hypothesis and model, as well as functionally distinguishable judgments – problem, assumption, idea and principle. Empirical forms of knowledge will be observation (experimental method) and fixation of facts. To evaluate the effectiveness of the developed pedagogical tools, we use statistical methods: observation (documented and interrogated) and calculation of generalizing indicators. To formulate conclusions, we will use logical methods: building conclusions and argumentation. The approbation of certain pedagogical tools described in this article showed a significant positive trend in terms of competence in information security issues.

scholarly journals Improving the stability and efficiency of anaerobic digestion of food waste using additives: A critical review

2018 ◽  
Vol 192 ◽  
pp. 316-326 ◽  
Author(s):  
Min Ye ◽  
Jianyong Liu ◽  
Chaonan Ma ◽  
Yu-You Li ◽  
Lianpei Zou ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Food Waste ◽  
Critical Review ◽  
The Stability
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