In recent years, research on the manipulation and control of microrobot has gradually matured. In order to improve the intelligence of microrobots, navigation study also becomes an important research topic. In practice, microrobots could be disturbed by the flowing liquid when it moves in a microfluidic environment. As a result, the actual trajectory of microrobots will deviate from the intended one. In this paper, firstly, different algorithms for the navigation of microrobots in a simulated plant leaf vein environment are investigated. According to the simulation results, RRT*-Connect is then selected as the path planning algorithm with a relatively better performance. Based on the pre-planned trajectory, a fuzzy PID controller is further designed for precise trajectory tracking, which can effectively eliminate the random disturbance caused by micro-fluid flow during the motion and make it quickly recover to a stable movement state.

The swine fever virus seriously affects pork production, and to improve pork production, pig breeding efficiency needs to be improved, and the detection of boar sperm activity is an important part of the pig breeding process. Traditional laboratory testing methods rely on bulky testing equipment, such as phase-contrast microscopes, high-speed cameras, and computers, which limit the testing scenarios. To solve the above problems, in this paper, a microfluidic chip was designed to simulate sperm in the oviduct with a channel thickness of 20 um, which can only accommodate sperm for two-dimensional movement. A miniature microscope system which can be used in combination with a smartphone is designed that is only the size of the palm of the hand and has a magnification of about 38 times. An intelligent diagnostic app was developed using Java language, which can automatically identify and track boar sperm with a recognition rate of 96.08% and an average tracking rate of 86%. The results show that the proposed smartphone-based hand-held platform can effectively replace the traditional microscope compound computer to diagnose sperm activity. In contrast, the platform is smaller, easier to use and is not limited by the usage scenarios.

Magnetic force-based manipulation has several advantages, including its minimally invasive feature and insensitivity to biological substances. Consequently, it has exhibited considerable potential in many medical applications, such as targeted delivery in precise medicine, in which microparticles are driven to the desired regions precisely in vivo. This study investigates an automated and accurate delivery of magnetic microparticles using a self-constructed electromagnetic coil system. After establishing a simplified second-order dynamic model of microparticles suspended in a fluidic environment, a visual-based automated controller that incorporates the concept of input-to-state stability (ISS) into fault-tolerant technique is developed. This controller enables microparticles to follow a desired trajectory under model uncertainties and environmental disturbances, and address the problem that the actual magnetic driving force may not reach the required value due to magnetic loss in the coil system simultaneously. Input constraint of the magnetic force provided by the system due to device capability is also considered in the fault-tolerant ISS-based controller design. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed approach.

Microparticle rotation is an important process in biomedical engineering, such as biosensors, cell injection or cell morphology. Single particle rotation has been widely investigated, while rotation of particle chains has gained rare attention. In this paper, we utilize a noncontact manipulation method to rotate microparticle chains via electrorotation by designing an octuple-electrode array (OEA). Finite element simulations were conducted for analyzing the desired electrode field and optimizing the structure of microelectrode pairs. The direction of the electric field in the workspace is investigated with different voltage signal inputs through specially designed circuits. In the experiment, microparticles are driven to form several chains in the proposed electrode fields. With the rotation of the electric field, particle chains could be rotated synchronously. Automated rotation and detection of polystyrene microspheres and yeast cell chains are achieved using machine vision technology. Results show that the proposed method could be utilized to rotate ordered microparticles with an appropriate input signal.

Electromagnetic actuation is a new technique for non-invasive manipulation, which provides wireless and controllable power source for magnetic micro/nano particles. This technique shows great potential in the field of precise mechanics, environment protection and biomedical engineering. In this paper, a new quadrupole electromagnetic actuated system is constructed, this system is composed of four electromagnetic coils, each of the coil is actuated by an independent DC power supplier. The magnetic field distribution in the workspace is obtained through finite element modeling and numerical simulation via COMSOL, as well as the effect of the current flow through the coil in the field distribution. Moreover, parameters of the electromagnetic system are optimized through parametric modeling analysis. A magnetic field map is constructed for rapidly solving the desired driving current from the required magnetic flux density. The proposed work provides theoretical references and numerical fundamental for the control of magnetic particle in future.