About Actuators

• Land Transport

This involves the primary function of transforming on-board energy into commands to wheels for land transport (motorcycles, cars, buses, trucks, trains, etc.). These wheel drives must be very durable (20,000 hours), very efficient (~85%), and independent to respond to command and to meet adverse operating conditions.

• Aircraft

The dominant requirements are fault tolerance (no single point failures), torque/force density, and efficiency. Generally, distributed control with a minimum weight, volume, etc. and standardized interfaces for rapid repair and refreshment are essential.

• Medical Instruments

Here, the question is reliability and miniaturization, especially in surgery or other invasive operations. It is useful also to have a high efficiency (low operating temperature and low noise), especially in rehabilitation systems.

• Robotics

This has now become a very diverse field, from industrial manipulators to mobile platforms used to move packages in internet-based distribution centers. Durability and cost are the major measures of success.

• Manufacturing

This involves two distinct application ranges. The first is the simple handling and preparation of product components for assembly (polishing, trimming, forming, painting, etc.). The other end of the spectrum involves high accuracy even under machining force disturbances. The first involves cost (system assembly, repair, and up-dates using standardized modules performed by a well-trained high school-level technician). The other end involves high value-added precision operations (machining, drilling, cutting, etc.), rejecting force disturbances using high-end sensor data and multi-criteria-based operating system software.

• Materials

This involves a very wide range of choices. For transport, low weight/high stiffness could be an issue. In the medical field, the material must be lucent relative to measurement signals (MRI, x-ray) during surgery. Some material applications may require a high formability, high resistance to chemicals, low contact friction, etc.

• Power/Torque Density

Increasingly, many high-level applications require a high output power or torque relative to the weight and volume. A prime mover may offer 1 ft-lb/lb. up to 6 ft-lb/lb. of torque. The prime mover may operate at a full range of speeds (say, from 1 to 50 k RPM) to offer a very wide range of power densities.  All of this is affected by the basic actuator reality, that it must control positive/negative operations through cross overs in the minimum time in order to best manage the complex output functions under command.

• Precision

A lot of applications are dominated by a need for precision response (position, velocity, acceleration, torque, etc.) to command. This is especially true of many medical, military, and manufacturing domains. Precision response depends first on having high-end sensors to measure the response quality to command, which informs the decision making software to respond to disturbances with the minimum latency.  Unfortunately, most actuators are highly nonlinear, making this topic of special value to all future high-end actuator applications.

• Miniaturization

Computer electronics based on the miniaturized chip are essential for advanced decision-making systems. The same is the case for actuators in the medical field, precision handling in small assemblies, product inspection, etc. Here, the piezo element likely becomes the principal prime mover fully integrated into a position/force/torque transformer to provide a wide range of very small physical operations under command.

• Control Systems

This involves actuators with advanced control system technologies in the field of their applications, integration, design methods and theories, as well as case studies. The topics include, but are not limited to, (1) new actuators for control systems; (2) novel control methods, such as intelligent control, and fault- and attack-tolerant control; and (3) case studies of actuator applications in emerging control systems, such as cyber-physical systems, man–machine systems, and intelligent systems.