When an accurate dynamic model of a mechanical manipu lator is available, it may be used in a nonlinear, model-based scheme to control the manipulator. Such a control formula tion yields a controller that suppresses disturbances and tracks desired trajectories uniformly in all configurations of the manipulator. Use of a poor dynamic model with this kind of model-based decoupling and linearizing scheme, however, may result in performance that is inferior to a much simpler, fixed-gain scheme. In this paper, we develop a parameter-adaptive control scheme in a set of adaptive laws that can be added to the nonlinear, model-based controller. The scheme is unique be cause it is designed specifically for the nonlinear, model- based controller and has been proven stable in a full, nonlin ear setting. After adaptation, the error dynamics of the joints are decoupled with uniform disturbance rejection in all ma nipulator configurations. The issues of sufficient excitation and the effect of disturbances are also discussed. The theory is demonstrated with simulation results and also with data from an implementation for an industrial robot, the Adept One.

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Redundant manipulators provide increased flexibility for the execution of complex tasks. Redundancy is often required to maintain manipulability and avoid obstacles while completing the required task. Self‐motion is the internal (joint) motion of the manipulator that does not contribute to the end effector motion. In this article we provide a dynamic feedback control law that guarantees the tracking of a desired end effector trajectory and provides redundancy resolution by making the self‐motion of the manipulator flow along the projection of a given arbitrary vector field. By choosing this vector field to be the gradient of a cost function, for example, the manipulator can be made to seek an optimum configuration. The effectiveness of the control law is illustrated with simulation results.

PurposeThe purpose of this paper is to contribute to the development of measures to assess the ERP adoption of small and medium‐sized enterprises.Design/methodology/approachThe paper follows Churchill's guideline for developing measures that have desirable reliability and validity. The pilot data are used to develop a proper measurement. The survey data, based on the 126 valid responses of 328 companies, are analysed by structural equation modelling (SEM) statistical methods.FindingsThe paper finds that the dimensions affecting ERP adoption show that characteristics of the CEO and perceived benefits possess positive effects on ERP adoption, while cost and technology have negative effects on ERP adoption. However, only “perceived benefits” is a significant dimension. It is surprising that the cost of the ERP system does not significantly affect ERP adoption.Research limitations/implicationsThe paper shows that the sample size should be taken into consideration when generalising the findings, and extended data and measures are required for further in‐depth investigation in specific areas.Practical implicationsThe paper points out that the managers of SMEs with limited resources can find many ways to get more resources from governments. Government managers should be more realistically set the goal of helping firms in a healthy condition to adopt e‐business instead of setting the goal of improving the e‐business readiness of all SMEs. To help all CEOs of SMEs to realise the potential benefits, governments can work with academic research groups to set up forums and workshops to broadcast knowledge.Originality/valueThe paper develops measurements to assess the ERP adoption of small and medium‐sized enterprises. The results offer practical help for government managers to better understand ERP adoption with institutional help in Taiwan. Meanwhile, researchers interested in IT/IS can use the information provided here to guide their future enquiries.

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