Search

The probe is the key component of the precision measurement equipment,and the development of the new type of probe is the focus of the field of precision measurement technology. The existing research mainly focuses on improving the measurement theory and optimizing the sensor performance,and has little research on the structural innovation of the probe body. Based on the basic property of the mechanism that the parallel mechanism is located in the singular configuration,a new kind of parallel compliant probe is constructed by using the method of rigid body replacement. The line geometry and the null space method of the force Jacobian matrix are used to explain the function freedom of mechanism required for the 3D probe. Based on the statics of the parallel compliant support mechanism and the stiffness model of the branched chain,the overall stiffness matrix of the mechanism and the force-displacement model of the probe are established. Besides,the correctness of theoretical analysis is verified by numerical simulation and finite element software. The research content expands the application scope of the parallel compliant mechanism,enriches the structural innovation method of the precision probe constraint support mechanism,and lays an important theoretical foundation for further constructing the new probe based on the type of parallel compliant mechanism.

Aiming at the actual situation of coal mines unmanned area,a four wheels drives small space detecting robot system for collecting information and samples of the underground environment is designed and developed. The robot is composed of a robot mechanism,travel mechanism,the controller and manipulator mechanism. The robot system components are described,the dynamics and static analysis of the 5 degrees of freedom manipulator is conducted to verify the rationality of its structural design and bearing performance in practical work. The results show that the change of each robot joint torques stable and did not exceed the limits value of the motor to provide. The maximum deformation of forearm is 0. 012 397 mm,the maximum stress on the system configuration 15. 802 9 MPa is little affected,it shows that 5 DOF manipulator type selection is accurate,structure design is reasonable,the practical needs of the coal mine is met.

Chinese kitchen environment is usually hot and humid in summer and cold in winter, while housewife spends considerable time there. This investigation developed a new ventilation system for Chinese kitchens to improve thermal comfort level. To assess the thermal performance of the ventilation system, 32 cooks were asked to prepare the same dishes in the kitchen with or without the system in summer in Changsha, China. The assessment was carried out by subjective questionnaire survey on thermal sensation vote (TSV) and objective on-site measurements of the indoor air temperature and cook’s skin temperature. The indoor air temperature was measured at different locations in the kitchen. The skin temperature was measured at 18 body parts of the cooks. The results show that the thermal environment in the kitchen was non-uniform and local thermal sensation had a great influence on the whole body sensation. Without the new ventilation system, the cooks complained that the hottest parts were thorax, head and face areas. Reasonably good correlation existed between the cooks’ skin temperatures and their thermal sensation votes. The increase of cooks’ skin temperature with the ventilation system was lower than that without the ventilation system. TSV was improved with the new ventilation system.

Thermal environment in residential kitchen in China is transient and non-uniform and with strong radiation asymmetry from gas stove. Due to the complexity of kitchen thermal environment, it is not sure if previous thermal comfort models can accurately predict the thermal comfort in residential kitchens. In order to evaluate if existing thermal comfort models can be applied for Chinese kitchens, this investigation conducted human subject tests for 20 cooks when preparing dishes in a kitchen. The study measured skin temperatures of the cooks and environmental parameters and used questionnaires to obtain their thermal sensation votes at the same time. The actual thermal sensation votes were compared with the predicted ones by four thermal comfort models: predicted mean vote (PMV) model, dynamic thermal sensation (DTS) model, the University of California at Berkeley (UCB) model, and the transient outdoor thermal comfort model from Lai et al. The results showed that all the models could predict the trend of the thermal sensations but with errors. The PMV model overpredicted the thermal sensations. The UCB and Lai’s models showed a slower change in thermal sensation votes (TSV) after turning on the stove. The DTS model was more accurate than the others in predicting the mean thermal sensation, but with a large variation in predicting individual thermal sensation votes. A better thermal comfort model should be developed for Chinese residential kitchens.