Measurement technology of operation region of EVA spacesuit
Operation ability of astronaut in spacesuit is a key parameter in Extra-vehicular activities. The operation region of people in the spacesuit was tested by 3-jointed mechanical measuring arm, which combined force-torque sensors in the handle, and magnetic brakes installed in every joint. Mathematical model of the measuring arm was established to transform the signals of sensors to the data required. The errors were analyzed and the system was calibrated and compensated. All tests were aided by computer, and data obtained were processed by software developed based on VC++, OpenGL and Matlab. An exact 3- D operation region of left hand, right hand and both hands was obtained by a method of reverse engineering. The measurement supplied solid support in space engineering design.
Testing and calibration of coordinate measuring arms
Portable coordinate measuring arms with rotational axes have found their place in many industrial areas. To establish and confirm the accuracy of these measuring devices, related test methods and appropriate devices are needed. After an introduction, a new high precision measuring device for testing and calibration of portable coordinate measuring arms is presented. Analysis showed that the best results can be obtained with a device for measuring along a straight line adjusted in various spatial directions. We discuss the design and construction of this measuring system and provide a theoretical calculation of its measurement accuracy, which was confirmed by experiments carried out on a prototype of a high precision measuring device in both unloaded and loaded conditions.
Modeling closed-loop mechanisms in robots for purposes of calibration
A method for modeling the significant parameters of closed-loop mechanisms in robots for purposes of calibration is presented. Nonlinear kinematic and mechanical characteristics of the closed-loop mechanisms are modeled in such a way that they can be integrated into an open-loop manipulator model and identified. This integration is accomplished through a separation of the spatial open-loop manipulator (defining the kinematic model) and its joint-actuating mechanisms or actuator models which can be nonlinear in the case of closed-loop mechanisms. Identifiability of model parameters (including elasticity) is analyzed and calibration results are presented.