Aiguo Patrick Hu

Low-Cost Autonomous 3-D Monitoring Systems for Hydraulic Engineering Environments and Applications With Limited Accuracy Requirements

The details of developing autonomous 3-D motion monitoring systems based on commercial off-the-shelf (COTS) motion sensors for hydraulic environments are discussed. Possible areas of application, are river bed sediment transport monitoring and monitoring the agitation and other physical parameters inside milk vats with a mechanized agitator. Simplified calculations of inertial navigation systems (INSs) such as Euler angle method, MATLAB programs for further processing, power management systems for autonomous operation including the possibility of inductive power transfer (IPT) and use of microelectromechanical systems (MEMS) technology are discussed. Experimental results for proof of concept systems are highlighted.

Electropermanent magnet based wireless microactuator for microfluidic systems: Actuator control and energy consumption aspects

Microfluidic systems are miniaturized networks of microchannels processing fluids in very small quantities. A wireless microactuator suitable to drive microfluidic microvalves is discussed in this paper. A microactuator powered and controlled wirelessly, and actuated using electropermanent magnets is developed. Hard and semi-hard magnetic materials are combined to form the controllable electropermanent magnet, which is capable of holding either of the valve states without the need for continuous power consumption. Experimental data has shown that actuation occurs over a very short period of 120μs and approximately just 2mJ of energy is consumed. The key feature of the actuator is the minimal energy consumption during actuation and zero energy consumption between actuations. Wireless power capability is achieved using inductive power transfer and the same link is utilized to deliver the binary open/close signal to the actuator. The actuator is self-sustained, due to the onboard supercapacitor energy storage which stores energy to source a few thousand actuations before fully discharging and meet the peak power requirement during the very short actuation period. These state latching, wirelessly powered actuators are particularly useful in enhancing the portability, reliability and electrical safety of microfluidic applications where energy and real estate are severely limited.

Design enhancements of the Smart Sediment Particle for riverbed transport monitoring

This paper discusses new enhancements that are being made to the existing ‘Smart Sediment Particle’. The smart sediment particle has been designed and implemented to track its own 3-dimensional trajectory when placed in a riverbed. This device serves as a tool to detect sedimentation in rivers. The device has been developed over the years, with its size diminishing significantly down to a sphere of 2cm radius. The readings obtained from the pebble are accurate and match well with other independent motion sensor readings. Currently a novel IPT (Inductive Power Transfer) based power supply is being integrated to this device, to charge it wirelessly, when it has been extracted from the water. A new low power, miniaturized microcontroller has been introduced to minimize the power consumption and the PCB real estate of the device. The paper discusses these new enhancements in detail and also other potential enhancements such as error compensation and wireless data transfer.

Preliminary development of an ultra low power electro-permanent magnet based actuator for microfluidic systems

An electro-permanent magnet based actuator has been proposed to control microvalves, which significantly reduces the energy consumption of solenoid type microvalves. Electro-permanent magnets are designed with combined hard and semi-hard magnetic materials to control the direction of the magnetic flux. Power is supplied to these magnets only to change the polarity of a magnet so that it can attract or repel the load. Therefore, power is only consumed to toggle between the states of the valve, while the actuator requires no power to maintain either close or open states at other times. Initial experiments revealed that a voltage as low as TV can be applied across the coil to switch the magnetization direction, which resulted in drawing a current of 1.76A during the current pulse duration of 100μs. The momentary power consumption was 12.37W, but the total energy consumption was only 1.237mJ for a state toggling. For applications where the valves are operated infrequently, this technique is highly energy economical as power is consumed for a very short period of time during actuation. Supercapacitor buffering is suggested to smooth out the energy requirement of the proposed actuator to make wireless low power transfer a possible solution for microfluidic systems with infrequent valve operations.