Shengli Tian, Xiaoan Chen, Tianchi Chen and Ye He
The purpose of this study is to investigate accurate and effective experimental methods for measuring the frictional loss of bearings (FLB) in mechanical systems and to measure…
Abstract
Purpose
The purpose of this study is to investigate accurate and effective experimental methods for measuring the frictional loss of bearings (FLB) in mechanical systems and to measure the effect of various operating parameters on the frictional loss of high-speed mechanical systems.
Design/methodology/approach
Two novel methods were studied in this paper to measure the FLB: the free-deceleration method and the energy-balance method. A special high-speed motorised spindle and a friction loss test rig were designed and built to measure the effects of rotational speed, lubrication, preload and operating temperature on the FLB.
Findings
The experimental results showed that the frictional torque of bearings increases initially but then decreases with an increase in rotational speed. Similarly, the FLB decreases initially and then increases with an increase in temperature because of the influence of the viscosity–temperature relationship of the lubricant and the thermomechanical coupling factor. The optimal lubricant flow was determined, and the effectiveness of a novel preload online adjusting device was verified through experiments.
Originality/value
The research results of this paper provide the basis and methods for the measurement, reduction and prediction of the FLB in mechanical systems.
Details
Keywords
Hongli Cao, Ye He, Xiaoan Chen and Xue Zhao
The purpose of this paper is to take transient contact force response, overshoots and steady-state force tracking error problems into account to form an excellent force controller.
Abstract
Purpose
The purpose of this paper is to take transient contact force response, overshoots and steady-state force tracking error problems into account to form an excellent force controller.
Design/methodology/approach
The basic impedance function with a pre-PID tuner is designed to improve the force response. A dynamic adaptive adjustment function that combines the advantages of hybrid impedance and adaptive hybrid impedance control is presented to achieve both force overshoots suppressing and tracking ability.
Findings
The introduced pre-PID tuner impedance function can achieve more than the pure impedance function in aspects of converging to the desired value and reducing the force overshoots. The performance of force overshoots suppression and force tracking error are maintained by introducing the dynamic adaptive sigma adjustment function. The simulation and experimental results both show the achieved control performance by comparing with the previous control methods.
Practical implications
The implementation of the controller is easy and convenient in practical manufacture scenes that require force control using industrial robots.
Originality/value
A superior robot controller adapting to a variety of complex tasks owing to the following characteristics: maintenance of high-accuracy position tracking capability in free-space (basic capabilities of modern industrial robots); maintenance of high speed, stability and smooth contact performance in collision stage; and presentation of high-precision force tracking capability in steady contact.
Details
Keywords
Chengguo Liu, Ye He, Xiaoan Chen and Hongli Cao
As more and more robots are used in industry, it is necessary for robots to interact with high dynamic environments. For this reason, the purpose of this research is to form an…
Abstract
Purpose
As more and more robots are used in industry, it is necessary for robots to interact with high dynamic environments. For this reason, the purpose of this research is to form an excellent force controller by considering the transient contact force response, overshoot and steady-state force-tracking accuracy.
Design/methodology/approach
Combining the active disturbance rejection control (ADRC) and the adaptive fuzzy PD controller, an enhanced admittance force-tracking controller framework and a well-designed control scheme are proposed. Tracking differentiator balances the contradiction between inertia and jump control signal of the control object. Kalman filter and extended state observer are introduced to obtain purer feedback force signal and uncertainty compensation. Adaptive fuzzy PD controller is introduced to account for transient and steady state performance of the system.
Findings
The proposed controller has achieved successful results through simulation and actual test of 6-axis robot with minimum error.
Practical implications
The controller is simple and practical in real industrial scenarios, where force control by robots is required.
Originality/value
In this research, a new practical force control algorithm is proposed to guarantee the performance of the force controller for robots interacting with high dynamic environments.
Details
Keywords
A framework of network support for utilization of integrated design over the Internet has been developed. The techniques presented are also applicable for intranet/extranet. The…
Abstract
A framework of network support for utilization of integrated design over the Internet has been developed. The techniques presented are also applicable for intranet/extranet. The integrated design system was initially developed for local application in a single site. With the network support, geographically dispersed designers can collaborate a design task throughout the total design process, quickly respond to clients’ requests and enhance the design agility. In this paper, after a brief introduction of the integrated design system, the network support framework is presented, followed by a description of two key techniques involved: Java Servlet approach for remotely executing a large program, and online CAD collaboration.
Details
Keywords
Zhifang Zhou, Tao Zhang, Jiachun Chen, Huixiang Zeng and Xiaohong Chen
This paper investigates the relationship between product market competition and firms’ water information disclosure and how firms’ ownership type can affect this relationship in…
Abstract
Purpose
This paper investigates the relationship between product market competition and firms’ water information disclosure and how firms’ ownership type can affect this relationship in China, offering new insights into corporate water management.
Design/methodology/approach
The authors investigated 303 Chinese listed companies in highly water-sensitive industries to examine how product market competition influences corporate water information disclosure by subdividing the product market competition into market competition at the firm level and the industry competition intensity at the industry level.
Findings
The results show that there exists an inverted U-shaped relationship between industry competition and water information disclosure; enterprises with the highest market power in a mildly competitive industry are more willing to voluntarily disclose water information and play an industry benchmarking role. Further tests demonstrate that the relationship between industry competition intensity and water information disclosure is stronger for state-owned enterprises than for private enterprises.
Research limitations/implications
The current water resources regulations in China are relatively lax and the water risk awareness of firms is weak, which may affect the applicability of the results. In addition, water information disclosure research is a relatively new field and a quantitative index system for water information disclosure is still in the exploratory stage. Further developments, including the selection, definition and measuring methods of a water index are required.
Practical implications
The authors developed a new direction of enterprise water management activities from the perspective of market competition. Based on the market conditions in China, the authors also investigated the impact of the ownership type of the enterprises on the relationship between market competition and water information disclosure.
Social implications
The authors suggested that the government should improve laws and regulations and adopt incentive mechanisms to encourage enterprises to implement water resource management. In addition, the government should encourage high market status enterprises to actively fulfill their environmental responsibilities so that the entire industry is encouraged to follow suit.
Originality/value
This study represents an important development in the field of environmental accounting and is the first research on corporate water information disclosure; it also extends the research on the influence mechanisms of market competition on the environmental management practices of enterprises.
Details
Keywords
Iván La Fé-Perdomo, Jorge Andres Ramos-Grez, Gerardo Beruvides and Rafael Alberto Mujica
The purpose of this paper is to outline some key aspects such as material systems used, phenomenological and statistical process modeling, techniques applied to monitor the…
Abstract
Purpose
The purpose of this paper is to outline some key aspects such as material systems used, phenomenological and statistical process modeling, techniques applied to monitor the process and optimization approaches reported. All these need to be taken into account for the ongoing development of the SLM technique, particularly in health care applications. The outcomes from this review allow not only to summarize the main features of the process but also to collect a considerable amount of investigation effort so far achieved by the researcher community.
Design/methodology/approach
This paper reviews four significant areas of the selective laser melting (SLM) process of metallic systems within the scope of medical devices as follows: established and novel materials used, process modeling, process tracking and quality evaluation, and finally, the attempts for optimizing some process features such as surface roughness, porosity and mechanical properties. All the consulted literature has been highly detailed and discussed to understand the current and existing research gaps.
Findings
With this review, there is a prevailing need for further investigation on copper alloys, particularly when conformal cooling, antibacterial and antiviral properties are sought after. Moreover, artificial intelligence techniques for modeling and optimizing the SLM process parameters are still at a poor application level in this field. Furthermore, plenty of research work needs to be done to improve the existent online monitoring techniques.
Research limitations/implications
This review is limited only to the materials, models, monitoring methods, and optimization approaches reported on the SLM process for metallic systems, particularly those found in the health care arena.
Practical implications
SLM is a widely used metal additive manufacturing process due to the possibility of elaborating complex and customized tridimensional parts or components. It is corroborated that SLM produces minimal amounts of waste and enables optimal designs that allow considerable environmental advantages and promotes sustainability.
Social implications
The key perspectives about the applications of novel materials in the field of medicine are proposed.
Originality/value
The investigations about SLM contain an increasing amount of knowledge, motivated by the growing interest of the scientific community in this relatively young manufacturing process. This study can be seen as a compilation of relevant researches and findings in the field of the metal printing process.