Research Interests


Dielectric Elastomers (DE)

Dielectric elastomers (DEs) represent a class of electro-mechanical transducers consisting of thin elastomer membranes (e.g., silicone, acrylics, natural rubber) coated with flexible electrodes (e.g., carbon-silicone mix, thin metal films) on both sides. When a high voltage is applied to the electrodes of a DE, the stored electric charges are subject to electrostsatic forces which cause a thinning of the membrane and, in turn, an area expansion. In this way, a controllable deformation can be obtained. DEs are characterized by large deformations (higher than 100%), high energy efficiency and density, high flexibility, fast response, lightweight, self-sensing capabilities, and low cost. This unique combination of features permits to develop DE based actuators, sensors, and generators capable of performance not achievable with conventional transducers. Eventually, actuation and sensing can be performed simultaneously by exploiting the so-called self-sensing mode, which allows to implement closed loop control architectures without introducing additional position or force sensors.

Our main research interests in this area are:

  • DE material characterization
  • DE material modeling
  • DE systems development
  • DE system modeling, control, and optimization
  • DE driving electronics
Shape Memory Alloys (SMA)

Thermal shape memory alloy (SMA) wires, such as NiTi ones, represent a specific class of smart materials which can be effectively used to design innovative mechatronic actuators. If an electric current is sent through the wire, the resulting Joule heating triggers a phase transformation in the SMA crystal lattice, which results in a change in shape up to 4–8%. If a pre–loading force is applied to the wire, e.g., by means of a pre–tensioned spring, the SMA restores its original shape when the current is removed. Such a principle can be effectively exploited to achieve muscle–like actuation modes. Compared to competing technologies, SMAs are characterized by a high energy density (up to 10 J/cm3), which permits to design compact and lightweight actuator devices. In addition, it is possible to relate the wire resistance to its deformation, enabling the use of SMAs as a self–sensing actuators.

Our main research interests in this area are:

  • SMA material characterization
  • SMA material modeling
  • SMA systems development
  • SMA system modeling, control, and optimization
  • SMA driving electronics


Modeling & simulation

Mathematical models is the starting point for proper understanding, optimization, and control of high-performance smart material systems abnd applications. At APS, the development of mathematical models and simulation tools represents a fundamental part of our research activities. We develop physics-based models based on different techniques and frameworks, which can be exploited for different applications and needs, i.e., optimization, simulation. control. Despite most of our modeling investigations are conducted on smart material transducers and systems, we are also interested in mechatronic systems in general.

Our main research interests in this area are:

  • Smart materials modeling
  • Smart material actuators, sensors, and generator systems modeling
  • Smart material lifetime and damage modeling
  • Hysteresis modeling
  • Energy-based modeling of multi-physics systems
  • Port-hamiltonian modeling
  • Hybrid dynamical modeling
  • Finite element modeling
Motion & interaction control systems

To ensure fast, accurate, and efficient operations in smart material systems, the development of control algorithms is of fundamental importance. At APS, we focus on developing and implementing control algorithms for different types of smart mart material systems and mechatronic actuators in general. Our research on control covers both theoretical and practical aspects, which are relevant for the control of motion, force, and interaction in physicsal systems.

Our main research interests in this area are:

  • Control methods for smart material systems
  • Hysteresis compensation and control
  • Motion control
  • Force/interaction control
  • Robust control
  • Optimal control
  • Energy-based control
  • Controller implementation
Sensorless methods

One of the main advantages of smart materials is the so-called self-sensing feature, i.e., the possibility of using the transducer as an actuator and as a sensor at the same time. This operation mode allows to reduce the size and cost of a smart material system, without removing all the benefits of feedback control. At APS, we focus on developing and implementing self-sensing architectures for different types of smart material transducers. By allowing the possibility tio estimate the material geometry and/or force during actuation, we enable the development of truly multifunctional systems.

Our main research interests in this area are:

  • Capacitive self-sensing methods for DE
  • Reistive self-sensing methods for SMA
  • Self-sensing methods for hysteretic systems
  • Self-sensing for multi degree-of-freedom smart actuators
  • Simultaneous force and displacement self-sensing
  • Sensorless control
  • Online self-monitoring
  • Self-sensing hardware development
  • Self-sensing architectures implementation
Real-time algorithm implementation

Experimental validation of the developed control and self-sensing algorithms represents a fundamental aspect of our research. Experimental validation of intelligent algorithms is addressed at APS at two levels. On the one hand, advanced simulink-based FPGA architectures allow rapid prototyping of complex real-time algorithms. On the other hand, the development of integrated smart actuators and applications requires the algorithms to be implemented in compact microcontroller architectures.

Our main research interests in this area are:

  • Experimental validation of control & self-sensing algorithms
  • Algorithms integration in high-performance FPGA systems for rapid prototyping
  • Algorithms integration in real-time microcontroller architectures


Continuum & Soft Robots

Conventional robots often rely on rigid structures and actuators to perform manipulation tasks. Despite being widely adopted in industrial environments, rigid robots often appear as unsuitable for the flexibility, lightweight, and safety requirements of modern applications. One relevant example is the field of human-robot cooperation, in which the rigid structure may represent a danger for a human operator. These needs have generated an interest in the field of soft robotics. This term refers to robots in which inherently soft materials are used to design the structure as well as actuators/sensors components. The improved compliance and safety features of soft robots allow to develop novel applications and human-robot interaction paradigms. At the same time, the availability of soft and tendon-like actuators makes it possible to realize continuum robotic structures, whose large number of degrees-of-reedom allows to achieve complex motion pattern which are hard or impossible to realize with conventional rigid robots. due to their unique mix of compliance, large deformations, and lightweight, smart materials such as DE and SMA represent highly suitable technology to implement actuation and sensing in continuum/soft robotic structures.

Our main research interests in this area are:

  • Soft robots based on DE transducers
  • Continuum robots based on SMA transducers
  • Novel concepts for continuum/soft robots based on smart materials
  • Continuum/soft robot system development
  • Continuum/soft robot system manufacturing
  • Continuum/soft robot system characterization
  • Continuum/soft robot system modeling
  • Motion and interaction control methods for continuum/soft robots
  • Self-sensing methods for continuum/soft robots
Distributed Soft Actuators

Up to date, most of small-scale DE applications rely on single degree-of-freedom systems, in which only one active element is used in a stand-alone configuration. In contrast, if many DE actuators are integrated in an array-like configuration and operated in a synergistic fashion, a cooperative system can be obtained. By combining the intrinsic compliance, energy efficiency, and self-sensing features of DE transducers with cooperative control paradigms, a new generation of distributed micro-actuators can be developed, with potential applications in fields such as soft robotics, distributed acoustics, wearables, and wave generators, to mention a few. In this perspective, at APS we work on the one hand to developing novel concepts for soft actuators and arrays, and investigate on the other hand novel models and control algorithms which ensure cooperative operation.

Our main research interests in this area are:

  • Full polymer-based soft actuators design and fabrication
  • Design and modeling of compliant bi-stable mechanisms
  • Design concepts for high-performance distributed arrays of soft DE actuators
  • Manufacturing and characterization of distributed arrays of soft DE actuators
  • Physics-based modeling of distributed arrays of soft DE actuators
  • Cooperative control and self-sensing algorithms for distributed arrays of soft DE actuators
Polymeric Loudspeakers

As a further research field, ad APS focuses on developing new polymeric loudspeakers concepts, in which the vibrating diaphragm and the actuator are combined into a soft DE membrane that can be adapted to arbitrary shapes or integrated into wearable textile structures. Compared to conventional acoustic devices, sucn types of DE-based loudspeakers take advantage of vibrations induced by direct application of a voltage on the acoustic diaphragm, with no need for external actuators. Experimental investigation with laser vibrometry equipment are combined with mathematical studies on the modal response and sound wave propagation of DE speaker devices. The understanding of the electro-hyperelastic-fluidic interactions occurring in DE loudspeakers open up the possibility of developing novel systems and concepts, such as distributed arryas of DE mini speakers or multi-functional DE actuators capable of implementing a low-frequency actuation task and generating an acoustic signal at the same time.

Our main research interests in this area are:

  • Novel concepts for flexible and distributed DE loudspeakers
  • DE loudspeakers design and manufacturing
  • DE loudspeakers optimization
  • DE loudspeakers characterization and modal analysis
  • DE loudspeakers modeling and simulations
  • Multi-field modeling of electro-hyperelastic-fluidic interactions
  • DE loudspeakers control strategies