Experimental and Numerical Study on the Semi-Closed Loop Control of a Planar Parallel Robot Manipulator

This paper implements the model predictive control to fulfill the position control of a 3-DOF 3-RRR planar parallel manipulator. The research work covers experimental and numerical studies. First, an experimental hardware-in-the-loop system to control the manipulator is constructed. The manipulator is driven by three DC motors, and each motor has an encoder to measure the rotating angles of the motors. The entire system is designed as a semiclosed-loop control system. The controller receives the encoder signals as inputs to produce signals driving the motors. Secondly, the motor parameters are obtained by system identification, and the controllers are designed based on these parameters. Finally, the numerical simulations are performed by incorporating the manipulator kinematics and the motor dynamics; the results are compared with those from the experiments. Both results show that they are in good agreement at steady state. There are two main contributions in this paper. One is the application of the model predictive control to the planar parallel manipulator, and the other one is to overcome the effects of the uncertainties of the DC motors and the performance of the position control due to the dynamic behavior of the manipulator

A Multiscale Mapping Assessment of Lake Champlain Cyanobacterial Harmful Algal Blooms

Lake Champlain has bays undergoing chronic cyanobacterial harmful algal blooms that pose a public health threat. Monitoring and assessment tools need to be developed to support risk decision making and to gain a thorough understanding of bloom scales and intensities. In this research application, Landsat 8 Operational Land Imager (OLI), Rapid Eye, and Proba Compact High Resolution Imaging Spectrometer (CHRIS) images were obtained while a corresponding field campaign collected in situ measurements of water quality. Models including empirical band ratio regressions were applied to map chlorophylla and phycocyanin concentrations; all sensors performed well with R² and root-mean-square error (RMSE) ranging from 0.76 to 0.88 and 0.42 to 1.51, respectively. The outcomes showed spatial patterns across the lake with problematic bays having phycocyanin concentrations \u3e25 μg/L. An alert status metric tuned to the current monitoring protocol was generated using modeled water quality to illustrate how the remote sensing tools can inform a public health monitoring system. Among the sensors utilized in this study, Landsat 8 OLI holds the most promise for providing exposure information across a wide area given the resolutions, systematic observation strategy and free cost

Remaining As A Leader or Not? Technology Spillover Answers

Much has been discussed about the advantages and disadvantages of being a first mover. However, discussion regarding the incentives encouraging a firm to remain as leader is absent in most studies. This paper aims to fill this gap and provide theoretical and empirical evidences vis-à-vis the incentives of remaining as a leader, by comparing profits between leader and follower when taking technology spillover and technological efficiency into consideration. The findings show that in regard to effective technological efficiency: (i) under the condition of a weak (strong) technology spillover, retaining the position of leader firm is (not) a dominant strategy because of higher (lower) profits than a follower; (ii) the half-shared technology spillover leads to an equal profit between firms, and implies a critical time of action for the leader firm to break the evenly-matched status by reconsidering first mover advantages; (iii) an empirical study on a data set of 352 high-tech and non-high-tech SMEs in manufacturing industry from 1999 until 2006 lends strong support to these results and may also provide useful clues for technology managers or practitioners to make better policies to benefit their market competitiveness