In the past decade, the technical requirements of control systems have become more stringent to be applicable to many aspects of industrial applications and automation devices, ranging from robots in manufacturing, underwater vehicles, and unmanned aerial vehicles to human–robot interaction. However, these applications and devices always need to operate in a complex environment. The growing number of applications in complex engineering environments, along with the increasing requirements and demands for the system stability, safety, and reliability, is posing new theoretical and technological challenges for the advanced controller design.

One major challenge is the provision of innovative solutions to deal with the complex operation environment. A general and illustrative definition of complex environment could be “a scenario which is dynamic and uncertain” (e.g., unknown environment model, high spatiotemporal complexity, rapid changes of light intensities, and unknown disturbances). The complex and dynamic environment often leads to a rapidly increasing complexity of the control algorithm and then results in difficulties for real-time controllers. Therefore, revealing the properties and behaviors of systems operating in the complex environment could not only bring in novel control designs but also provide solutions for systems operating realistically and efficiently in complex and unmodeled scenarios.

This special issue will present advances in the control design for systems operating in complex environments and will provide a comprehensive overview of future solutions from various computational and engineering aspects. The authors are invited to present mathematical theories, algorithms, frameworks, experiments, and applications aiming at bringing about advanced control techniques for systems working within complex and unpredictable behaviors such as structural/structural uncertainties, unknown nonlinearities, time-varying delays, unknown external disturbances, unpredictable human motions, and uncertain system dynamics.

Potential topics include but are not limited to the following:

• Robot manipulator control in complex environments
• Human–robot interaction in complex environments
• Underwater vehicle control in complex environments
• Robot motion learning in complex environments
• Unmanned aerial vehicle control in complex environments
• Fault-tolerant control in complex environments
• Robot sensing and exploring technologies in complex environments
• Disturbance observation based control in complex environments
• Complex gesture/motion recognition with multimodal information
• Optimization for systems in complex environments