A Dynamically Balanced Kinematically Redundant Planar Parallel Robot

A dynamically balanced robotic manipulator does not exert forces or moments onto the base on which it is fixed; this can be important for the performance of parallel robots as they are able to move at very high speeds, albeit usually have a reduced workspace. In recent years, kinematically redundant architectures have been proposed to mitigate the workspace limitations of parallel manipulators and increase their rotational capabilities; however, dynamically balanced versions of these architectures have not yet been presented. In this paper, a dynamically balanced kinematically redundant planar parallel architecture is introduced. The manipulator is composed of parallelogram linkages which reduces the number of counter rotary-elements required to moment balance the mechanism. The balancing conditions are derived, and the balancing parameters are optimised using Lagrange multipliers, such that the total mass and inertia of the system is minimised. The elimination of the shaking forces and moments is then verified via a simulation in the multi-body dynamic simulation software MSC Adams.

Firm Growth Performance and Relative Innovation Orientation of Exploration vs Exploitation: Moderating Effects of Cluster Relationships

ABSTRACT This article studies the latent mechanisms underlying the non-linear correlation between a firm's relative innovation orientation of exploration vs exploitation and performance. We also investigate the moderating effects of cluster relationships on this relationship. Using a sample of 638 SMEs in four industry clusters in Tianjin, China, we confirm an inverted U-shaped correlation between a firm's relative innovation orientation and performance, and explicate the latent mechanisms underlying such an inverted U shape. We find that the number and strength of a firm's cluster relationships can moderate this inverted U-shaped curve: the former moves the turning point of the inverted U shape toward exploratory orientation, and the latter moves the turning point toward exploitative orientation. For improved performance, we discuss appropriate innovation balancing strategies for cluster firms with different cluster relationships, and optimal cluster strategies under different innovation-balancing conditions. This study adds to the increasing scholarly effort on latent mechanisms behind U-shaped relationships and moderating effects on such relationships in management research.

Analyzing the balancing problem at the stages of creating high-tech products

Subject. The most important and responsible stage of justifying State programs for high-tech product creation is the balancing of program activities. This task becomes especially urgent when fulfilling the customer requirements for efficiency and quality of high-tech products under tight constraints on fund allocation. Objectives. The study aims to create a general balancing model based on a comprehensive analysis of the conceptual and methodological framework of balancing in various fields of activity. Methods. As a starting methodological premise – a scientific hypothesis, we substantiate the use of the principle of scientific syllogism, which includes general and special premises and a conclusion containing new scientific knowledge, and the principle of self-organization to take into account internal processes of balancing. Results. We formulated a conceptual framework for balancing to support the creation of high-tech products. On its basis we developed a general model and described its main parts, including the goal of balancing, conditions, criteria and parameters, and the result of balancing. We also formulated the general problem of balancing and methods to solve it. The paper shows that the problems of balancing and optimization on the one hand and the task of self-organization on the other hand are identical. Conclusions. The obtained results can be used to improve methodological tools to manage the creation of high-tech products while developing long-term technological programs, mitigate the risk of their implementation, define of sustainable innovative and technological development of the country.

A Static Balancing Method for Variable Payloads by Combination of a Counterweight and Spring and Its Application as a Surgical Platform

Stackable mechanism architecture has demonstrated effective gravity-balancing over entire workspaces. Adjustable balancing is required when balancing is broken due to changing the payload at the distal end of a mechanism. In this paper, adjustable balancing of the stackable mechanism for a variable payload is investigated. For this, balancing conditions for three adjustable balancing methods are suggested, and a new balancing method combining a spring and counterweight is considered as an effective means of adjustable balancing for variable payloads. The excellent performance of the system is proven through experiments. Electromyography (EMG) sensors are employed to measure the amount of energy expenditure during the drilling task. It was verified through several tests that an operator holding a drill mounted at the distal end of a stackable arm felt less energy compared to an operator holding the drill directly in free space. The developed balancing arm was successfully applied during a mastoidectomy. A 3-step warning algorithm along with a braking function was found to be effective for safe surgery.

Model of Consecutive, Steady-State Underflow for Vertical Tailing Silos

A continuous tailing discharge model is proposed for solving the problems of high fluctuation in underflow concentration and low, unstable actual discharge concentration in vertical tailing silos. On the basis of the mass balance equation, a mathematical model for continuous tailing discharge is derived, and a partial differential equation related to the height of the tailing silo in the compression area and tailing slurry concentration is obtained. The effective solid stress equation and the solid flux equation can be obtained from the results of centrifuge tests and intermittent sedimentation tests. The volume concentrations of underflow corresponding to various heights of tailing surfaces are simulated by using fluid mechanics software under dynamic balancing conditions. The results of the simulations are highly similar to those calculated by the derived mathematical model of continuous tailing discharge, and the results of the industrial test are also closely related to the results of the differential equation, thereby verifying the accuracy of the proposed discharge model.