Peng Zhao

Zhejiang University | ZJU · State Key Laboratory of Fluid Power and Mechatronic Systems

In contrast with jumping robots made from rigid materials, soft jumpers composed of compliant and elastically deformable materials exhibit superior impact resistance and mechanically robust functionality. However, recent efforts to create stimuli-responsive jumpers from soft materials were limited in their response speed, takeoff velocity, and trav...

The rapid development of ocean exploration and underwater robot technology has put forward new requirements for underwater sensing methods, which can be used for hydrodynamic characteristics perception, underwater target tracking, and even underwater cluster communication. Here, inspired by the specialized undulated surface structure of the seal wh...

The advancements in tactile sensor technology have found wide-ranging applications in robotic fields, resulting in remarkable achievements in object manipulation and overall human-machine interactions. However, the widespread availability of high-resolution tactile skins remains limited, due to the challenges of incorporating large-sized, robust se...

Soft robot incarnates its unique advantages in deep-sea exploration, but grapples with high hydrostatic pressure’s unpredictable impact on its mechanical performances. In our previous work, a self-powered soft robot showed excellent work performance in the Mariana Trench at a depth of 11 000 m, yet experienced notable degradation in deforming capab...

Quality prediction plays an essential role in industrial process monitoring and optimization. However, the existed methods lack of the ability to extract features in multiphase and nonlinear time series data. To improve the quality prediction accuracy and simultaneously provide some suggestion of the process mechanism, this article proposes a phase...

In mass production, injection molding plays a vital role in manufacturing various parts with complex settings. As perfluoroalkoxy alkane (PFA) injection‐molded products are widely used in immersion system, dimensional quality needs more attention. However, there is limited research on the dimension defects of PFA injection‐molded products. This stu...

Manufacturing flexible magnetic-driven actuators with complex structures and magnetic arrangements to achieve diverse functionalities is becoming a popular trend. Among various manufacturing technologies, magnetic-assisted digital light processing (DLP) stands out because it enables precise manufacturing of macro-scale structures and micro-scale di...

The successful exploration of the Mariana Trench, Earth's deepest trench, by soft robots inspired by deep-sea organisms, showcasing the potential of soft robots for extreme deep-sea exploration. However, deep-sea extreme pressure significantly alters the structure and properties of robot materials, affecting their detectability. In this study, to e...

Tactile sensory organs for three-dimensional (3D) force perception are essential for most living organisms and enable them to perform complex and sophisticated tasks to survive and evolve. Magnetic-based tactile sensors have been developed rapidly in recent years due to the exploitability of 3D force decoupling. Here, a method of magnet splicing is...

The advancements in tactile sensor technology have found wide-ranging applications in robotic fields, resulting in remarkable achievements in object manipulation and overall human-machine interactions. However, the widespread availability of high-resolution tactile skins remains limited, due to the challenges of incorporating large-sized, robust se...

Novel testing method is an important research direction in the field of mechanical engineering. Magnetic levitation testing method has proved its advantages of high accuracy and sensitivity in density-based analysis. Therefore, trials in testing materials and products for materials processing using magnetic levitation have achieved series of progre...

Magnetism, a captivating natural phenomenon, has intrigued human curiosity and scientific inquiry for centuries. The ability of certain materials to exert attractive or repulsive forces on other objects without direct physical contact has given rise to a rich history of exploration and discovery. From the enigmatic lodestones of ancient times to th...

Magnetic labels are widely used to aid in the separation and purification of chemical and biological samples. These labels typically consist of superparamagnetic nano- or microspheres, such as Invitrogen’s Dynabeads, which can be covalently attached to a variety of chemical and biological samples. For instance, immunomagnetic separation involves th...

In the study of electromagnetic phenomena, this chapter delves into the domain of magnetic forces, shedding light on the intricate relationship between electric charges, currents, and fields.

It is well known that the density is the basic character of a substance. Density measurement is an important characterization method for both static and dynamic analysis and for inferences of chemical composition in specific experiments. For example, the density of polymers depends not only on their chemical composition, but also on how the chains...

Earnshaw's Theorem, formulated by Samuel Earnshaw, serves as a foundational principle within classical mechanics (Simon et al. in Am J Phys 69:702–713, 2001; Geim et al. in Nature 400:323–324, 1999), positing the impossibility of point particles achieving stable equilibrium solely under classical inverse square law forces. This theorem resonates th...

The invention of magnetic levitation detection method brings us a potential density measurement and density-based analysis method. The advantages of standard MagLev device have been proved to be (i) of high accuracy, (ii) of high sensitivity, (iii) applicable to smaller objects, such as droplets and powders, (iv) convenient, and (v) low cost.

A maglev train will be the first thing come up to a man’s imagine when he hears “magnetic levitation”. For it is well known that magnets will be repel each other when their same poles getting close. However, it is impossible to use a single magnet to levitate another magnet. This phenomenon was firstly proved by Earnshaw in 1842 through theoretical...

As introduced in previous sections, magneto-Archimedes levitation is one of the few methods that can levitate and control objects without direct touch. In addition, it has been theoretically proved that stable levitation can be achieved solely in a stable magnet field instead of using accurate control or other methods, which means it is possible to...

As one of the inherent characteristics of cell, density is a significant biomarker for the analysis and investigation of multiple cellular events. Density profiles of cell populations are informative data concerning physiological research such as differentiation, live-death assay, aging, immune response, or drug resistance (Durmus et al. in Proc Na...

The magnetic levitation method, characterized by its simplicity, absence of sample magnetization requirements, and convenient operation, has found extensive applications not only in fields such as chemical analysis, biological measurements, and performance characterization but also in the non-contact manipulation of small-sized weakly magnetic mate...

Tactile sensory organs for sensing three‐dimensional (3D) force, such as human skin and fish lateral lines, are indispensable for organisms. With their sensory properties enhanced by layered structures, typical sensory organs can achieve excellent perception as well as protection under frequent mechanical contact. Here, inspired by these layered st...

In chip manufacturing, ultraclean environment is essential during wet processes such as etching, cleaning, and other stages. The fittings used in the process require corrosion resistance, which are made of perfluoroalkoxy alkanes (PFA) by injection molding. Metallic contamination is one of the major impurities for ultraclean products. This study de...

Density variation during the injection molding process directly reflects the state of plastic melt and contains valuable information for process monitoring and optimization. Therefore, in-situ density measurement is of great interest and has significant application value. The existing methods, such as pressure—volume—temperature (PVT) method, have...

Curved-surface components (CSC) are ubiquitous in engineering practice such as automobiles, aerospace and pipelines. However, they are prone to void and crack defects which greatly degenerate mechanical properties and are badly in need of effective detection. Ultrasonic full-matrix imaging is a conspicuous method in nondestructive testing. However,...

Tactile sensory organs for three-dimensional (3D) force, such as human skin and fish's lateral line, are indispensable for creatures. Empowered by their often layered structure, typical sensory organs can achieve excellent perception as well as protection when facing frequent mechanical contact. Here, inspired by these layered structures, we introd...

Tactile recognition is among the basic survival skills of human beings, and advances in tactile sensor technology have been adopted in various fields, bringing benefits such as outstanding performance in manipulating objects and general human-robot interactions. However, promoting enhanced perception of the existing tactile sensors is limited by th...

Particle swarm optimization (PSO) is widely used in the parameter estimation for complex models, which is the key to establishing a mathematical model. However, convergence to the local optimal easily occurs in PSO. A substantial amount of researches have been conducted to improve the evolutionary process of PSO; nonetheless, the study on initializ...

For molding equipment, the accurate measurement of tie-bar stress helps improve product quality and prolong the lifespan of the machine. In our previous work, the mathematical model between the ultrasonic time difference (UTD) and the tie-bar stress was established, and this model was shown to have high accuracy with the maximum of difference squar...

The rotation of circular and annular pyrolytic graphite (PG) disks levitating above circular magnet arrays can be used for a novel method of magnetic manipulation, whereas the condition of stable levitation has not been figured out yet. In this article, a method to analyze the diamagnetic forces sustained by levitated PG is proposed to investigate...

Multilayer composite structures are essential for various fields but void defects inside will greatly reduce its mechanical properties. Ultrasonic full-matrix capture (FMC) is a useful imaging modality to detect defects in multilayer structures, but it also brings heavy computational burden. Though great progress has been made in the full-matrix im...

Polyether-ether-ketone (PEEK) has been widely used in aerospace field for its excellent performance. Microcellular injection molding (MIM) is a promising method to reduce product weight and save energy consumption. In this study, microcellular PEEK was prepared by injection molding. Firstly, the thermal properties of raw PEEK, injection molded PEEK...

Polyether-ether-ketone (PEEK) is an excellent engineering polymer with numerous advantages. Processing by microcellular injection molding (MIM) can reduce product weight and save energy consumption. However, conventional MIM is plagued with limited weight-reduction and poor surface quality, so there have been few reports on microcellular PEEK with...

In die casting, the real-time measurement of the stress of the tie-bar helps ensure product quality and protect the machine itself. However, the traditional magnetic-attached strain gauge is installed in the mold and product operating area, which hinders the loading and unloading of the mold and the collection of die castings. In this paper, a meth...

High efficiency separation is a significant process of the mechanical recycling to manage the mixed waste plastics. However, most of the extant methods can only deal with binary mixtures. In this paper, a novel automatic and continuous separation method based on magneto-Archimedes levitation is proposed to handle multi-plastics. A theoretical model...

Multilayer polymer composite structures have been playing important roles in various fields, but the voids inside are not allowed in most scenarios. Ultrasonic technology has been widely used to inspect voids in concrete and metal structures. However, the application of ultrasonic imaging in polymer composite structures is severely blocked by the c...

Separation is crucial for recycling heavy metals, however, most of the reported processes focus on separating metals from non-metals. Here we propose a magnetic levitation (MagLev) configuration to separate heavy metals from metallic mixtures. The novel configuration is able to levitate substances with specific densities over 5.00 g/cm3, while the...

Soft actuators are attracting increasing attention for their great potentials in transportation, exploration and clinical treatments, especially the magnetic-driven soft actuators powered by magnetic energy wirelessly. However, the further promotion of complicated three-dimensional magnetic-driven soft actuators with multiple applications is limite...

Standard magnetic levitation (MagLev) device consists of two identical square permanent magnets with like poles facing each other. Limited by the size of the permanent magnet, standard MagLev device cannot afford the levitation of samples with large size. This paper proposed a novel MagLev device using magnet arrays to replace the whole permanent m...

The research of functional magnetic materials has become a hot topic in the past few years due to their fast, long-range, and precise response in diverse environments. Functional magnetic devices using different magnetic materials and structure designs have been developed and demonstrated good advantages to enable various applications. However, the...

Air pollution caused by particulate matter and toxic gases is violating individual’s health and safety. Nanofibrous membrane, being a reliable filter medium for particulate matter, has been extensively studied and applied in the field of air purification. Among the different fabrication approaches of nanofibrous membrane, electrospinning is conside...

The development of flexible tactile sensors is an emerging field due to their wide applications ranging from human-robot interactions to wearable electronics. This paper proposes a flexible tactile sensor based on the magnetic field for detecting both forces and positions, which exhibited a linear relationship. The direct ink writing technology was...

Magnetic projection, a novel separation method proposed recently, can separate multiple mixed materials in an efficient and low-cost way. Although promising, existing magnetic projection method cannot achieve the automatic feeding of mixed materials, which limits its applications. To address this challenge, ring magnets were used to replace convent...

Intelligent injection molding consists of three aspects: intelligent parameter optimization, process monitoring and control. The optimal process parameters are critical to guarantee product quality. Injection molding is a typical batch process and has the property that previous runs can provide feedback to optimize subsequent runs. This study propo...

Injection molding is regarded as the most significant process to manufacture high-quality polymer products. However, the molten polymer undergoes drastic variations of temperature in the cavity during injection molding, which strongly affects the dimensional accuracy, weight consistency and crystallinity of the molded products. Therefore, it is of...

Magnetic levitation (MagLev) is one of the novel methods that attracts attention from researchers all over the world. It is an accurate and sensitive density testing method that can have applications in the fields of manipulation of particles and cells, chemistry, materials science, and biochemistry, etc. This review mainly focuses on the theory an...

This paper presents a single-electromagnet levitation device to measure the densities and detect the internal defects of antimagnetic materials. The experimental device has an electromagnet in its lower part and a pure iron core in the upper part. When the electromagnet is activated, samples can be levitated stably in a paramagnetic solution. Compa...

Shrinkage voids have a large influence on the quality of plastic gears, and it is still a problem to detect the voids inside gears accurately and conveniently. This paper presents a novel method for detecting shrinkage voids via magnetic levitation. The porosity levels of plastic gears can be calculated using magnetic levitation because the density...

Separating multiple mixed wastes in one step remains a serious challenge because mixtures often have to be separated using a stepwise approach. Bidirectional magnetic projection was thereby developed; the process separates mixed materials simultaneously in a container full of paramagnetic medium by sending the materials from the releasing position...

The quality of the polymer raw material used in plastic processing methods is an important characteristic because it is one of the main factors in producing quality products. Therefore, the characterization of polymeric pellets in the polymer processing industry is very important to avoid using inferior materials. In general, differences in the int...

Magnetic levitation (MagLev) is a promising technology for density-based analysis and manipulation of diamagnetic ob-jects of various physical forms. However, one major drawback is that MagLev can only be performed along the central axis (one- dimensional MagLev), thereby leading to (i) no knowledge about the magnetic field in regions other than th...

Injection molding is one of the most significant material processing methods for mass production of plastic products. It is widely used in various industry sectors, and its products are ubiquitous in our daily life. The settings and optimization of the injection molding process dictate the geometric precision and mechanical properties of the final...

Product weight is one of the most important properties for an injection-molded part. The determination of process parameters for obtaining an accurate weight is therefore essential. This study proposed a new optimization strategy for the injection-molding process in which the parameter optimization problem is converted to a weight classification pr...

In-situ characterization of the molecular orientation during injection molding process remains a great challenge. Failing to penetrate the metallic mold, many conventional methods cannot realize the online measurements during the injection molding process. In comparison, longitudinal ultrasound provides a promising method due to its deep penetratio...