Precise position control of a Travelling Wave Ultrasonic Motor is achieved, avoiding the traditional drawbacks attributable to non-linear torque generation: overshoot or slow response time. For that purpose, a behavior model control is proposed and presented. With this control law, a quick and precise response is obtained. In this article, we present a position control scheme of an inertial load. The guideline used for this control was a rotation of 90 0 in a response time of about 200ms with a position error of 0.6mrad, targeting a typical application for avionics. In the paper, a shinsei USR30 is used, but the method can be applied to other Ultrasonic Motors.

International audiencePrecise position control of a Travelling Wave Ultrasonic Motor is achieved, avoiding the traditional drawbacks attributable to non-linear torque generation: overshoot or slow response time. For that purpose, a behavior model control is proposed and presented. With this control law, a quick and precise response is obtained. In this article, we present a position control scheme of an inertial load. The guideline used for this control was a rotation of 90deg in a response time of about 200ms with a position error of 0.6mrad, targeting a typical application for avionics. In the paper, a shinsei USR30 is used, but the method can be applied to other Ultrasonic Motors

Using Piezo electric actuators can reduce the bulk size of servomechanisms; they are thus very useful in avionics applications. However, mechanical overload on the shaft of a Traveling Wave Ultrasonic Motor often results in the motor suddenly stalling. To avoid this drawback, one can increase the supply voltage or add a control loop in the rotating reference frame of the traveling wave. The consequences are extra power losses or lower dynamic performances. The proposed method combines the advantages of classical controls and controls in a rotating frame: both stability and dynamic performances are obtained at low supply voltage levels. Experimental runs are presented.

The latest events of ground-to-air Man Portable Air Defense (MANPAD) attacks against aircraft have revealed a new threat both for military and civilian aircraft. Consequently, the implementation of Protecting systems (i.e. Directed InfraRed Counter Measure -DIRCM) in order to face IR guided missiles turns out to be now inevitable. In a near future, aircraft will have to possess detection, tracking, targeting and jamming capabilities to face single and multiple MANPAD threats fired in short-range scenarios from various environments (urban sites, landscape …).In this paper, a practical example of a DIRCM system under study at SAGEM DEFENSE & SECURITY company is presented. The self-protection solution includes built-in and automatic locking-on, tracking, identification and laser jamming capabilities, including defeat assessment. Target Designations are provided by a Missile Warning System. Multiple Target scenarios have been considered to design the system architecture.The article deals with current and future threats (IR seekers of different generations…), scenarios and platforms for system definition. Plus, it stresses on self-protection solutions based on laser jamming capability. Different strategies including target identification, multi band laser, active imagery are described. The self-protection system under study at SAGEM DEFENSE & SECURITY company is also a part of this chapter.Eventually, results of self-protection scenarios are provided for different MANPAD scenarios. Data have been obtained from a simulation software. The results highlight how the system reacts to incoming IR-guided missiles in short time scenarios.