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The metallic layers are an essential part of MEMS (micro electromechanical system) devices, and their deposition process must be accurately controlled; this may lead to difficulties as there are many input parameters for such a process. This research focuses on the input parameters' effects on the Ni pulse-reverse electroplating. A neural network was constructed to characterize the pulse-reverse nickel electroforming process parameters. The sample training has accurately established the mapping relationship between input and output parameters. The nickel layer thickness and surface roughness prediction in the pulse-reverse electroplating process was realized and verified by experimental tests with a test error of 3.3%. Then, the effect of direct and reverse current density, deposition time, structure width, and stirring speed as input parameters on the thickness and surface roughness are investigated. Finally, a novel 4D diagram has been developed to derive the optimal values of direct and reverse current density relative to thickness, surface roughness, and deposition time. This diagram can help researchers and industries find suitable parameters to achieve the desired deposited Ni layer's properties. [ABSTRACT FROM AUTHOR]

Pavement roughness is one of the essential parameters of pavement quality affecting ride quality, driving safety, and fuel consumption. The International Roughness Index has been widely deployed to evaluate pavement surface roughness. A vibration-based system is developed by using a low-cost three-axis Micro-Electro-Mechanical Systems accelerometer and a Global Positioning System sensor, which are connected to an Arduino board and embedded in a vehicle to monitor the road condition. The pavement profile is obtained by double integration of Z-axis acceleration data, and then the International Roughness Index is calculated via the Process Valves & Automation Systems Software using the obtained profile. The calculated International Roughness Index is correlated with ground truth data captured by a Road Surface Profiler with the coefficient of determination of 0.82 and an average error of 15%. The results demonstrate that the developed system can calculate the International Roughness Index with adequate accuracy at the network level. Besides, due to the low system cost and ease of use, it can be widely applied by road users to monitor pavement roughness as a crowdsourcing-based data collection system. [ABSTRACT FROM AUTHOR]

Nature has always inspired engineers. This research tries to understand the contribution of snake anatomy in its locomotion from engineering point of view to be adopted in the design of snake robots. Rib design and muscular structure of snake robots will have a great impact on snake robot flexibility, weight, and actuators' torque. It will help to eliminate wheels in snake robots during serpentine locomotion. The result of this research shows that snakes can establish the required peg points on smooth surfaces by deflecting the body and ribs. The results are verified by both field observations and simulation. [ABSTRACT FROM PUBLISHER]

Piezoelectric actuators (PEAs) are frequently used in a wide variety of micromanipulation systems. However, the hysteresis non-linearity and the creep reduce their fidelity and cause difficulties in the micromanipulation control procedure. Besides, variation of temperature and external loads could change the model parameters identified for the piezo actuator. In this paper, a robust feedforward–feedback controller is proposed for precise tracking control of PEAs, under external disturbances. A Bouc–Wen hysteresis model is integrated with a second-order linear dynamic, to represent the behaviour of a PEA. Based on the Bouc–Wen model, a hysteresis observer is developed to estimate the hysteresis non-linear effect. Then, for real-time compensation of the observer error and the thermal and external load disturbances, a sliding mode control (SMC) strategy with a perturbation estimation function is utilized. To verify the efficiency of the proposed method, a comparison between the proposed approach and a classical SMC is presented. [ABSTRACT FROM AUTHOR]