Wen Yu, Xiaoou Li and Roberto Carmona
– This paper aims to address a new iterative tuning method of PID control for robot manipulators.
Abstract
Purpose
This paper aims to address a new iterative tuning method of PID control for robot manipulators.
Design/methodology/approach
This tuning method uses several properties of the robot control, such as any PD control can stabilize a robot in regulation case, the closed-loop system of PID control can be approximated by a linear system, the control torque to the robot manipulator is linearly independent of the robot dynamic.
Findings
Compared with the other PID tuning methods, this novel method is simple, systematic, and stable. The transient properties of this PID control are better than the other normal PID controllers.
Originality/value
In this paper, a new systematic tuning method for PID control is proposed. The paper applies this method on an upper limb exoskeleton, and real experiment results give validation of our PID tuning method.
V.O. Gamarra‐Rosado, G. Fernández, J.C. Grieco, M. Armada and N. Aliane
States that control is of the essence in cybernetics. Summarizes the dynamic equations for a flexible one‐link manipulator moving in the horizontal plane. Employs the finite…
Abstract
States that control is of the essence in cybernetics. Summarizes the dynamic equations for a flexible one‐link manipulator moving in the horizontal plane. Employs the finite element method, based on elementary beam theory, during the process of formulation. Develops and instruments a one‐link flexible manipulator in order to control its vibration modes. Uses a simple second‐order vibration model which permits vibrations on the rod to be estimated using the hub angle. The validation of the dynamic model and the structural analysis of the flexible manipulator is reached using proper infrared cameras and active light sources for determining actual positions of objects in space. Shows that the performance of the control is satisfactory, even under perturbation action.
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Mamoru Minami, Julien Agbanhan and Toshiyuki Asakura
This paper presents the real‐time visual servoing of a manipulator and its tracking strategy of a fish, by employing a genetic algorithm (GA) and the unprocessed gray‐scale image…
Abstract
This paper presents the real‐time visual servoing of a manipulator and its tracking strategy of a fish, by employing a genetic algorithm (GA) and the unprocessed gray‐scale image termed here as “raw‐image”. The raw‐image is employed to shorten the control period, since it has more tolerance of contrast variations occurring within an object, and between one input image and the next one. GA is employed in a method called 1‐step‐GA evolution. In this way, for every generational step of the GA process, the found results, which express the deviation of the target in the camera frame, are output for control purposes. These results are then used to determine the control inputs of the PD‐type controller. Our proposed GA‐based visual servoing has been implemented in a real system, and the results have shown its effectiveness by successfully tracking a moving target fish.
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Changhoon Kim and Jae H. Chung
The paper aims to develop a robotic deburring method based on a new active pneumatic tool.
Abstract
Purpose
The paper aims to develop a robotic deburring method based on a new active pneumatic tool.
Design/methodology/approach
The paper presents a new active pneumatic tool, which is developed by integrating two industrial pneumatic deburring tools based on a double cutting action – initial cut followed by fine cut. A simple control method is developed, which coordinates the motion of the tools and the arm.
Findings
The study finds that the developed method can improve robotic deburring in terms of speed and accuracy.
Research limitations/implications
The paper provides guidance for the design of a pneumatic deburring tool, its integration with an industrial robot, and robotic deburring control.
Practical implications
The new deburring tool prevents large contact force and bouncing from occurring during the contact transition. In addition, the developed deburring method demonstrates significant improvement in deburring speed and accuracy in comparison with other methods, which is translated into cost‐effective deburring.
Originality/value
The paper introduces an efficient robotic deburring method, which is developed based on a new active pneumatic tool, considers the interaction among the tool, the manipulator, and the workpiece, and couples the tool dynamics and a control design.
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Yanan Li, Keng Peng Tee, Rui Yan and Shuzhi Sam Ge
This paper aims to propose a general framework of shared control for human–robot interaction.
Abstract
Purpose
This paper aims to propose a general framework of shared control for human–robot interaction.
Design/methodology/approach
Human dynamics are considered in analysis of the coupled human–robot system. Motion intentions of both human and robot are taken into account in the control objective of the robot. Reinforcement learning is developed to achieve the control objective subject to unknown dynamics of human and robot. The closed-loop system performance is discussed through a rigorous proof.
Findings
Simulations are conducted to demonstrate the learning capability of the proposed method and its feasibility in handling various situations.
Originality/value
Compared to existing works, the proposed framework combines motion intentions of both human and robot in a human–robot shared control system, without the requirement of the knowledge of human’s and robot’s dynamics.
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Chenglong Yu, Zhiqi Li, Dapeng Yang, Hong Liu and Alan F. Lynch
This study aims to propose a novel method based on model learning with sparsity inducing norms for estimating dynamic gravity terms of the serial manipulators. This method is…
Abstract
Purpose
This study aims to propose a novel method based on model learning with sparsity inducing norms for estimating dynamic gravity terms of the serial manipulators. This method is realized by operating the robot, acquiring data and filtering the features in signal acquisition to adapt to the dynamic gravity parameters.
Design/methodology/approach
The core principle of the method is to analyze the dictionary composition of the basis function of the model based on the dynamic equation and the Jacobian matrix of an arm. According to the structure of the basis function and the sparsity of the features, combined with joint-angle and driving-torque data acquisition, the effective features of dynamic gravity parameters are screened out using L1-norm optimization and learning algorithms.
Findings
The theoretical analysis revealed that training data obtained based on joint angles and driving torques could rapidly update dynamic gravity parameters. The simulation experiment was carried out by using the publicly available robot model and compared with the previous disassembly method to evaluate the feasibility and performance. The real 7-degree of freedom (DOF) industrial manipulator was used to further discuss the effects of the feature selection. The results show that this estimation method can be fully operational and efficient in industrial applications.
Research limitations/implications
This approach is applicable to most serial robots with multi-DOF and the dynamic gravity parameters of the robot are estimated through learning and optimization. The method does not require prior knowledge of the robot arm structure and only requires joint-angle and driving-torque data acquisition under low-speed motion. Furthermore, as it is a data-driven-based method, it can be applied to gravity parameters updating.
Originality/value
Different from previous general robot dynamic modelling methods, the sparsity of the analytical form of dynamic equations was exploited and model learning was formulated as a convex optimization problem to achieve effective gravity parameters screening. The novelty of this estimation approach is that the method does not only require any prior knowledge but also does not require a specifically designed trajectory. Thus, this method can avoid the laborious work of parameter calibration and the induced modelling errors. By using a data-driven learning approach, the new parameter updating process can be completed conveniently when the robot carries additional mass or the end-effector changes for different tasks.
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Srinivasan Alavandar and M.J. Nigam
The purpose of this paper is to present the control of a six degrees of freedom (DOF) robot arm (PUMA robot) using fuzzy PD + I controller. Numerical simulation using the dynamic…
Abstract
Purpose
The purpose of this paper is to present the control of a six degrees of freedom (DOF) robot arm (PUMA robot) using fuzzy PD + I controller. Numerical simulation using the dynamic model of six DOF robot arm shows the effectiveness of the approach in trajectory tracking problems. Comparative evaluation with respect to PID and fuzzy PID controls are presented to validate the controller design. The results presented emphasize that a satisfactory tracking precision could be achieved using fuzzy PD + I controller combination than fuzzy PID controller.
Design/methodology/approach
Control of a six DOF robot arm (PUMA Robot) using fuzzy PD + I controller.
Findings
The performance of fuzzy PD + I controllers improves appreciably compared to their respective fuzzy PID only or conventional PID counterparts.
Originality/value
Complexity of the proposed fuzzy PID controller is minimized as possible and only two design variables are used to adjust the rate of variations of the proportional gain and derivative gain.
Details
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Haixia Wang, Xiao Lu, Wei Cui, Zhiguo Zhang, Yuxia Li and Chunyang Sheng
Developing general closed-form solutions for six-degrees-of-freedom (DOF) serial robots is a significant challenge. This paper thus aims to present a general solution for six-DOF…
Abstract
Purpose
Developing general closed-form solutions for six-degrees-of-freedom (DOF) serial robots is a significant challenge. This paper thus aims to present a general solution for six-DOF robots based on the product of exponentials model, which adapts to a class of robots satisfying the Pieper criterion with two parallel or intersecting axes among its first three axes.
Design/methodology/approach
The proposed solution can be represented as uniform expressions by using geometrical properties and a modified Paden–Kahan sub-problem, which mainly adopts the screw theory.
Findings
A simulation and experiments validated the correctness and effectiveness of the proposed method (general resolution for six-DOF robots based on the product of exponentials model).
Originality/value
The Rodrigues rotation formula is additionally used to turn the complex problem into a solvable trigonometric function and uniformly express six solutions using two formulas.
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Nidhi Agarwala, Ritu Pareek and Tarak Nath Sahu
The study aims to explore and establish the relationship that exists between board independence and corporate social responsibility (CSR) practices of Indian firms.
Abstract
Purpose
The study aims to explore and establish the relationship that exists between board independence and corporate social responsibility (CSR) practices of Indian firms.
Design/methodology/approach
A sample of 76 non-financial companies listed on the National Stock Exchange has been considered for a period of seven years (from 2013 to 2019). The study has used several statistical tools such as the static panel data model and the Arellano–Bond dynamic panel data model based on generalized method of moments approach.
Findings
The results of the analysis have indicated board independence to have a significant positive relationship with the firms’ CSR performance. However, board size and number of board meetings have been found to have a negative relationship with CSR. Further, outcomes have also revealed that variables such as companies’ size and liquidity have a positive effect on the extent of CSR activities performed.
Practical implications
The firms which have the intention to engage in impactful CSR activities should support the independent directors’ participation in companies’ boards. The study’s findings suggest the companies to appoint independent directors strategically, keeping in mind the requirements of their board. Also, the independent directors selected should be independent in true sense, i.e. they should not be acquaintances of the company’s chief executive officer. This would ensure unbiased decision-making and would enhance the company’s CSR performance.
Originality/value
In India, CSR has gained great importance. So much so that it was made mandatory by the Companies Act, 2013. However, research studies that may assist in understanding the influence of board independence on Indian firms’ CSR performance are still scarce. The present study would foster value to the existing set of limited literature. Besides, the study has considered the dynamic nature of the relationship and has also controlled the endogeneity bias which has been examined by few studies in the past.
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Suchismita Ghosh, Ritu Pareek and Tarak Nath Sahu
The study aims to focus to ascertain the consequence of corporate management and different firms' characteristics on environmental sustainability.
Abstract
Purpose
The study aims to focus to ascertain the consequence of corporate management and different firms' characteristics on environmental sustainability.
Design/methodology/approach
The sample includes 78 non-financial NSE 100 listed companies from 2010 to 2020. Here, the static and Arellano–Bond dynamic panel data model is considered to determine the effect of corporate governance mechanisms and different firms’ characteristics on environmental performance.
Findings
The empirical findings of this study indicate that board size is negatively related with environmental sustainability. Similarly a positive influence of age, size and market-based financial performance can be seen on sustainability of the firm.
Originality/value
The present study takes an initiative to determine endogeneity and the dynamism effect of corporate governance factors and specific firms' characteristics on environmental sustainability from an emergent nation.