The physical devices that couple electrical signals to mechanical input and output are critical to the success of any active system. In most cases the efficiency, linearity, size, and weight of these devices are at least as important as the control system connecting them. CSA designs active systems using sensors to measure motion, vibration, sound, temperature, and pressure. CSA also develops custom actuators to meet a wide range of requirements on force, displacement or other quantities. Electromagnetic devices are designed with the aid of sophisticated magnetic modeling software. Solid state piezoelectric components are integrated into devices. Other advanced devices incorporate pneumatic or hydraulic components. Our engineers execute component and device level characterization of systems including sensors and actuators, providing for predictable and efficient integration of components into larger systems.

CSA has taken the next step in device design with the integration of electronic conditioning, control, and power management components with the transducers. In so doing, we take advantage of rapidly improving electronics technology to create smart devices.

Sensors

CSA makes use of the sensors appropriate for the active system under development. Building on a long tradition of vibration testing, sensors for acceleration, velocity, motion, load, sound, temperature, pressure, magnetic field, flow and other quantities are used. With a large collection of high quality laboratory sensors, comprehensive and accurate testing aids in development. CSA has recently begun using advanced optical sensors for a variety of purposes ranging from motion measurement to wavefront imaging.

Actuators

Exerting real influence on a physical system requires more than just an idea of what should happen. It requires an actuator capable of turning that idea into a physical quantity such as force or rotation. An actuator translates an electronic signal into a physically meaningful action. CSA's expertise in actuators has been developed in a long history of vibration testing and control. Numerous methods for transduction exist. CSA chooses the right method for a particular physical system. We employ electromagnetic, piezoelectric, hydraulic, pneumatic or other actuation methods as required. We have recently begun standardizing our line of electromagnetic actuators to provide customers with a wide choice of high quality devices.

Motors

CSA is currently developing a family of motors based on piezoelectric materials. The high energy density piezoelectrics are being exploited for high efficiency alternatives to conventional electromagnetic motors. In one project, rotary devices are being designed using piezoelectrics. With an integrated microcontroller-based drive and control system, the devices are being designed for maximum end-to-end power conversion efficiency. The motors will also deliver higher torque than existing devices. After proof of concept, the scale of the motors will be reduced to allow compatibility with MEMS-style fabrication methods. In a separate effort, linear motors that combine high force capacity with microprecision positioning are being tested in the laboratory.

Hydraulics and Hybrid Devices

CSA has used hydraulic devices in laboratory testing for many years. Hydraulics provide high force capacity in a small volume. More recently, we have begun to exploit hydraulics for different purposes, such as the actuators in a multiple-axis motion simulator. CSA is also beginning to develop compact hybrid actuators that combine hydraulics with smart materials such as piezoelectrics, electrostrictives, or magnetostrictives. Development of novel electrohydraulic devices is the focus of a DARPA-funded effort led by CSA called Smart Material Actuated Servo Hydraulics (SMASH).

Magnetorheological (MR) Devices

CSA Engineering recently expanded its field of expertise to include magneto-rheological (MR) and electro-rheological (ER) device design and development services. With rheological fluids, application of a magnetic or electric field controls the effective fluid viscosity, from zero-field, passive mode operation to full-field mode. This provides the ability to vary the rate at which the device absorbs energy. Applications such as automobile active suspension systems can take advantage of MR fluid controllable shock absorbers that have no internal moving part. Rotational applications such as braking systems and variable torque transfer units utilize controllability without physical material contact and wear. More on MR/ER devices...