Abstract: A compact two-dimensional angle sensor with a measurement resolution that exhibits superior sensitivity has been designed based on the autocollimator principle to enable the precision measurement field to measure the pitch and yaw error motions of a moving object. The signal drift of this sensor affects the measured angle and is mainly caused by the change in environmental temperature. To improve the thermal stability of the sensor, computer simulation has been conducted using the finite element analysis software ANSYS 16. Simulation results show that the angle sensor is considerably stable to adopt mechanisms with a symmetrical structure. Thus, a modified optimal angle sensor is developed, and its thermal stability has been verified via contrast experiments. Compared with the original sensor, the average drift of the optimized angle sensor is reduced from 0.430 arcsec∕°C to 0.120 arcsec∕°C when the variation of the environmental temperature is 5 °C. The optimal angle sensor is ideal for high-precision measuring equipment.
Abstract: A novel A/B bi-rotary head is designed which can be used on five-axis machine centers. The motion of pitching and swing can be achieved by controlling the output angle and velocity of motors. Anti-backlash control method can be applied to eliminate the transmission backlash. The error sensitivity model is also established using matrix differential method, and the influence of internal errors on the integrated errors is obtained. The results show that the more sensitive errors can be identified from all errors which need to be controlled rationally.
Abstract: This paper focuses on the simulation of clutch engagement behavior in automated manual transmissions (AMTs) to virtualize the vehicle start-up maneuver through implementation of the driveline model and the role of transmission control unit featuring different levels of knowledge regarding to clutch material frictional response. Simulation results underline the crucial requirement of accurate prediction of the frictional coefficient evolution in each clutch maneuver, particularly regarding to the interface temperature estimation to develop effective models and control algorithms.
Abstract: The appearance of high power LED has put forward higher requirements for thermal management. The micro heat pipe (MHP) has high heat transfer ability and plays an important role in high power LED and other high heat flux device cooling. In this paper, we designed and fabricated a micro heat pipe with fluoroalkyl silane (FAS) surface modified glass cover. The contact angle of the working area of glass cover reached 95.49° and made working fluid drops fall back to micro groove of silicon substrate more quickly. Thus the new glass cover can speed up the circulation of working fluid and enhance the heat transfer. The experimental results also proved that hydrophobic glass cover has a better heat transfer capability. Besides, this novel MHP reached the stable working status faster. When the input heat power was 10 W, the balance temperature of MHP with hydrophobic glass cover was 22 oC lower than traditional MHP, while the balance time is 58 seconds less. The work presented in this paper provides a new direction for optimize the MHP, not only the wick structure in substrate, but also the wettability of cover plate.
Abstract: In this paper, we designed a set of multipurpose intelligent detecting and controlling system for automatic assembly force. To actualize detecting, analyzing and controlling hole-peg assembly force. Firstly, we founded the assembly model, and simulated and analyzed the main factors which make great effect on axial force. We briefly introduced the assembly mechanism, compliant wrist and paw, the functions and operational principles of this system. This system has three detecting modes, users can select one from the three in “mode selection”, and they can also set the parameters. We also designed the hardware and the software. We tested and simulated all the modules for many times to improve their reliability and facticity. At last, we illustrated the anti-jamming measures we took in the design. After all the tests, this system could work well.
Abstract: Heat transfer capability of micro heat pipe (MHP) is relied on the thermal resistance of material, the specific phase change latent heat of working fluid, and the pattern of micro structures which is served as wick. In this paper, parallel and trapezoidal micro Cu structures were designed and fabricated by UV-LIGA. The capillary pressure and the effective coefficient of heat transfer conductivity of the micro grooves were calculated and results showed that trapezoidal grooves with small dimension in evaporator and large dimension in condenser (forward trapezoidal) have the best performance, because this structure can generate larger capillary force of working fluid and enhance the heat transfer. Two MHPs based on the calculations were fabricated and tested, results demonstrated that forward trapezoidal groove had the lowest equilibrium temperature while the inversed trapezoidal groove had the highest equilibrium temperature, approved the numerical calculation results. When the input power was 10W, the equilibrium temperature of forward trapezoidal, parallel and backward trapezoidal grooved MHP was 67.2 oC, 73.4°C and 89.1 oC, respectively. The forward trapezoidal grooves enlarge the capillary pressure and benefit the heat transfer of MHP.
Abstract: To suppress the abrupt and unexpected turning velocity fluctuation of the industrial robot under the condition of trajectory tracking, a flexible robotic joint experimental setup with the harmonic drive was established. The measured friction with Stribeck effect and velocity were modeled by a simple polynomial fit method. Two friction compensation control strategies of feedforward and feedback were designed. The friction compensation experiments were carried out on the dSPACE system, the good restraint effect of fluctuation on the turning velocity was verified and the control accuracy of feedback compensation control strategy proved better.
Abstract: In the industrialized cultivation process of fungi, CO2 concentration control system is a nonlinear, time-delay and time-varying system, which is difficult to establish a precise mathematical model. Considering the situation, CO2 concentration prediction model that based on neural network was built, and a fuzzy controller was proposed further based on the prediction model. Finally, matlab/labview based online forecast model was finished, and it is verified that the prediction system has higher prediction accuracy with robust character. It also provides a new approach to control key environmental factors under more favorable conditions for mushroom growth.
Abstract: A digital closed-loop control system with all digital phase locked loop (ADPLL) is designed and optimized, in order to improve the bias stability and transient response of the gyroscope. The nonlinear mathematical models for the closed-loop amplitude and phase control system are established. The linearization method is applied to analyze the nonlinear models. The control parameters of the drive loop are optimized. The experimental results show that the phase deviation between the demodulation reference signal of the drive loop and the sense signal is less than 0.25° in the temperature range from-40°C to 60°C, within 0.15° of the variation. At room temperature, the overshoot amount of the gyroscope control system is 4.5% with setting time of 0.12s. The bias stability is 1.45°h. Compared to the analog control scheme, the digital control system has advantages of short setting time, small overshoot, short phase locked time, large locked range, high phase precision, etc.