We are pioneering a paradigm shift in engineering through the strategic employment of nonlinearity—establishing a groundbreaking theoretical and methodological framework for nonlinear design, analysis, and control. This novel approach has demonstrated profound enhancements in system performance, reliability, and energy efficiency across diverse engineering domains, including vibration suppression, energy harvesting, fault detection, robotic systems, propulsion mechanisms, and sensor technologies.
Our central thesis posits that nonlinear dynamics are not merely challenges to be mitigated but powerful assets to be harnessed. We have committed ourselves to uncovering the fundamental principles and developing innovative methodologies that elucidate the intrinsic benefits of nonlinearity and provide actionable strategies for its integration into engineering systems.
This philosophy diverges sharply from conventional design and control paradigms, positioning our work at the forefront of applied nonlinear dynamics. Our contributions are substantiated by over 260 SCI-indexed publications with 7 Springer monographs, accumulating more than 14,000 citations and an H-index of 63 (Google Scholar), and are encapsulated in several authoritative Springer volumes. Several recent high-impact review articles further highlight our influence:
Bio-Inspired Vibration Isolation: Methodology and Design, Applied Mechanics Reviews, 2021
A Review of Bioinspired Vibration Control Technology, Applied Sciences, 2021
A. Nonlinear System Design Theory
We have identified and characterized a class of beneficial nonlinearities—nonlinear stiffness, damping, and inertia—that significantly enhance vibration control and other system behaviors. Our generic design methodology, known as the X-structure/mechanism method, enables systematic integration of these nonlinearities, driving continuous innovation and leadership in the field.
B. Nonlinear Analysis and Optimization Framework
To facilitate efficient nonlinear optimization, we developed a parametric characteristic approach - the nCOS function method - that directly links structural parameters to objective functions. This methodology represents a radical departure from traditional optimization techniques, offering superior clarity and computational efficiency.
C. Robust Nonlinear Control Theory
Our novel vibration control theory (i.e., Energy-saving robust control) achieves up to 80% energy savings without compromising performance, while dramatically reducing computational overhead compared to classical methods such as LQG, MPC, and other optimal control strategies.
D. Advanced Fault Diagnosis Methodology
By leveraging nonlinear dynamic features, we have created fault diagnosis techniques that are markedly more reliable and effective -- The SOOS. These methods have broad applicability—from satellites and bridges to turbine blades and engines—and were recognized with the HKIE Best Paper Award in 2019 and 2023 respectively.
E. Aquatic Robotics Innovation
Applying our nonlinear design principles to robotics, we have developed aquatic robots equipped with nonlinear propulsion systems that deliver superior thrust, agility, and energy efficiency in harsh aquatic environments. These innovations create a new R&D area for analysis and design of bionic aquatic robots, and have secured substantial research funding and resulted in multiple patent filings.
We focus on application oriented robotic systems: bio-inspired robots, construction robots, marine robots, and other novel robotic applications such as exoskeleton technology, security inspection robots or structural health monitoring robots etc, and related control, navigation and motion planning methods. A track-based robot with a novel quasi-zero-stiffness suspension system is developed; Several bio-inspired robots are developed either with multiple octopus-like tails, undulating fins of omni-directional motion capability, or quadruped mechanisms, and a crossing-discipline team is formed for several benchmark applications with marine robots currently supported by strategic focus area funds; We are also developing novel field and construction robots for special tasks in industry.
Currently, we have several PhD, Postdoc or Research Assistant positions opening for robot control, navigation, motion planning, sensor systems, and novel propulsion mechanisms etc.
A CRF project about bio-inspired underwater robots is now on-going with positions openning !
We focus on development of new generation of vibration isolators/absorbers or vibration suppression by employing nonlinear benefits, active/passive sound and vibration control, bio-inspired approach, vibration sensors based on quasi-zero/zero stiffness concepts, nonlinear energy harvesting, vibration based fault detection and structural health monitoring etc;
I initiated, proposed and have been leading my team to establish a bio-inspired limb-like or X-shaped structure/mechanism approach to vibration control (especially for passive vibration control), e.g., bio-inspired limb-like, human body inspired anti-vibration structures/mechanisms, while quadrilateral or polygon mechanisms are actually sharing the same nonlinear mechanism. This approach can overcome many obvious drawbacks of existing other methods for exploring nonlinear benefits in design of equivalent nonlinear stiffness, damping and inertia/mass characteristics. There are a series of applications and benchmark technical innovations in nonlinear stiffness, nonlinear damping and nonlinear inertia.
The bio-inspired limb-like or X-shaped structures and applications
The quasi-zero or zero-stiffness based vibration sensors:
A novel concept for absolute vibration displacement measurement; The quasi-zero or zero-stiffness with passive structure design is innovatively explored and employed which can create an absolute stable point in a broadband frequency domain and thus can be employed for vibration measurement, not only in static environments but also in moving platforms. This presents an innovative way to solve the issue for absolute vibration displacement measurement existing in the related field for many years.Nonlinear Energy Harvesting by employing nonlinear properties and structural benefits
[B3.1] LI Meng, Jing Xingjian*, Novel tunable broadband piezoelectric harvesters for ultralow-frequency bridge vibration energy harvesting, Applied Energy, Applied Energy 255, 113829, Dec 2019[B3.2] Qian JG, Jing XJ*, Wind-driven Hybridized Triboelectric-Electromagnetic Nanogenerator and Solar Cell as a Sustainable Power Unit for Self-powered Natural Disaster Monitoring Sensor Networks, Nano Energy, 52:78-87, October 2018[B3.3] Wei CF, K Zhang, C Hu, Y Wang, H Taghavifar, Jing XJ, A Tunable Nonlinear Vibrational Energy Harvesting System with Scissor-like Structure, accepted by Mechanical Systems and Signal Processing, June 2018[B3.4] Li M, Zhou JJ, Jing XJ*, Improving Low-Frequency Piezoelectric Energy Harvesting Performance with Novel X-structured Harvesters, Nonlinear Dynamics, 94 (2), 1409-1428, Oct 2018[B3.5] Wei CF, Jing XJ*, A comprehensive review on vibration energy harvesting: modelling and realization, Renewable & Sustainable Energy Reviews, 74(1-18), 2017[B3.6] Wei CF, Jing XJ*, Vibrational energy harvesting by exploring structural benefits and nonlinear characteristics, Communications in Nonlinear Science and Numerical Simulation, 48: 288–306, 2017[B3.7] Liu CC, Jing XJ*, Nonlinear Vibration Energy Harvesting with Adjustable Stiffness, Damping and Inertia, Nonlinear Dynamics, 88(1), 79–95, 2017 (doi:10.1007/s11071-016-3231-1)[B3.8] Liu CC, Jing XJ*, Vibration Energy Harvesting with a Nonlinear Structure, Nonlinear Dynamics, 84(4), 2079-2098, 2016Employing nonlinear benefits in nonlinear active control systems has been studied in our group and it is revealed that much more robust control can be achieved together with significant energy saving performance. This series of research results present a novel insight into robust control of nonlinear systems and benchmark applications can be found in vehicle suspension systems.
We focus on a recently developed GFRF and nonlinear characteristic output spectrum (NCOS) based method and applications (vibration control, bio-systems, mechanical systems, fault detection etc); A systematic characteristic analysis approach has been established for the analysis and design of nonlinear systems in the frequency domain with a series of applications and pioneering work in vibration control, fault detection and energy harvesting etc.
We have interests in developing vibration signals based fault detection or diagnosis methods. We proposed a fault diagnosis method for complex structures with least prior knowledge, less testing data and other practical requirements. A recent work is done for bolt loosening of a satellite-like structure with a “virtual beam” approach, which actually presents a nonlinear feature dynamics based method under further investigation now. We are also developing some new fault-related nonlinear features by using our research results in the frequency-domain nonlinear analysis and design.
Control, identification and signal processing
We have interest in development of robust control theory or methods in general to solve critical theoretical and/or practical issues focusing more on application oriented control methods [D.1-5]. For system identification, we developed a new robust control approach, which casts the traditional identification problem with input output data into a robust control or robust output feedback control problem and thus achieve more powerful and robust identification performance [D.6-10]. We focus on kernel learning based approach, robust control approach, robust learning methods with NARX models, block-oriented nonlinear models (Wiener/ Hammerstein models), Volterra/Wiener kernel methods, and Neural networks for distributed/lumped parameter systems and stochastic systems, and their applications (mechanical systems, biological systems, neuronal systems, time-series data analysis, fault detection, structural health monitoring etc); Novel intelligent computing or optimization methods are also of interest to us.