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And in a move to cut costs, Applied continues to expand in Asia. ''Applied is in the midst of a transition of its manufacturing/ supply chain to Asia,'' Muse said. ''While semiconductor related manufacturing would be moved to Singapore as well as China, solar related manufacturing and research is being relocated to Xian, China and display related manufacturing to Taiwan. Singapore will also likely serve as a supply chain co-ordination hub.''

SG73P2ATTD1802D_Datasheet PDF

And in a move to cut costs, Applied continues to expand in Asia. ''Applied is in the midst of a transition of its manufacturing/ supply chain to Asia,'' Muse said. ''While semiconductor related manufacturing would be moved to Singapore as well as China, solar related manufacturing and research is being relocated to Xian, China and display related manufacturing to Taiwan. Singapore will also likely serve as a supply chain co-ordination hub.''

The orthoses hold the arm and feature three passive rotational degrees of freedom (DOF) to ensure the limb is always aligned comfortably within the robots. Physiotherapists record the movements by guiding the limb through a therapeutic movement via the distal segments of the robot. The system records the forces applied to the arm and movement of the robot joints. The movement can then be replayed by the iPAM system, which assists the patient as required throughout the movement. The level of assistance provided by iPAM.

Control System The iPAM robots are required to provide active motive forces to assist movement of the human arm. Therefore, it is essential that the robots effectively coordinate because misalignment or excessive force applied to the limb could cause pain or injury. To accomplish this, a novel control scheme is used that operates around the DOF of the human joints rather than the Cartesian end points of the robots. The arm is simplified to a six-DOF model with five DOF at the shoulder (two translations and three rotations) and one at the elbow. Because the robots can control three DOF each, it is possible to constrain the six DOF of the upper limb.

SG73P2ATTD1802D_Datasheet PDF

The human joint angles are not directly measurable by iPAM, so they must be estimated from known kinematic data of the arm and the positions of the relative attachment points of the robots using a direct inverse kinematics formulation for the human arm model. This formulation cannot cope with the measurement errors inherent from the soft tissue interfaces (skin, muscle, and orthosis padding) and with kinematic singularities at the shoulder joint.

However, a new iterative formulation was developed using a Jacobian transpose method, based on the forward kinematics of the arm and it is much easier to evaluate. Crucially, the method is aware of measurement error and kinematic singularities. To provide accurate estimation of the arm's position, 50 iterations of the forward kinematics are processed per iteration of the control loop, which runs at 500 Hz. This places high-computational demands on the real-time controller and necessitates deterministic real-time performance for reliability.

By transforming the forces measured by each robot into the upper limb coordinate system, we can implement an admittance control scheme in which assistance can be targeted to particular joints of the upper limb. The admittance controls scheme functions by measuring the torque and forces at each human DOF and modulating the desired joint position depending on stiffness and damping parameters set by the therapist.

SG73P2ATTD1802D_Datasheet PDF

Using high assistance (high stiffness setting) the robot closely follows the therapist's prescribed movement. This is appropriate for patients with little active movement. Lowering the assistance (lower stiffness setting) allows greater deviation from the prescribed movement and is used for patients with a greater range of active movement or as a patient's mobility improves. Assistance to each joint of the model can be altered independently while preserving the coordination pattern of the movement.

Implementation We implemented the iPAM real-time controller using the LabVIEW Real-Time Module and NI interface cards to perform the signal I/O functionality of the controller. The input sensors comprise two six-axis force transducers, six contactless rotary sensors, three potentiometers that measure shoulder position, and several digital inputs used for safety switches. Analog output signals control 12 paired pressure-regulating valves that drive low-friction pneumatic cylinders at each robot joint. The controller is fully state-based, making the code logical, expandable, and easy to audit. The real-time OS allows deterministic execution of the controller, helping ensure that the entire system is dependable and safe.

SG73P2ATTD1802D_Datasheet PDF

The physiotherapist uses a client laptop, launched with a UI to provide the patient with instructions, exercise cues, and performance feedback to interface with the iPAM system. The client communicates asynchronously with the real-time controller via an Ethernet link using the TCP protocol. The main component of the UI is the 3D workspace representation. Written using the OpenGL-based 3D picture controls in LabVIEW, it allows task-specific information to be delivered in real time to patients.

Norwood, Mass.—Analog Devices Inc. has introduced two new RF ICs for broadband communications systems that it says reduce component count by more than 75 percent in point-to-point radios, wireless base stations, cable infrastructure, and communications test equipment, without compromising performance.

According to ADI, the ADRF6655 active mixer or ADRF6510 dual programmable filter and VGA (variable gain amplifier) integrate multiple functions and discrete devices into a single monolithic chip, reducing component count by a factor of four when compared to traditional discrete RF designs.

Operating within the 100 to 2500 MHz frequency range, the ADRF6655 device is a highly-flexible, single-chip, broadband, active mixer with a fully integrated fractional-N phase locked loop (PLL) synthesizer, voltage controlled oscillator (VCO) and associated low dropout (LDO) regulator circuits. The PLL and VCO provide a fully integrated LO (local oscillator) circuit that can also be brought off-chip for external use. The ADRF6655 active mixer operates on a single +5 V supply and features input linearity IP3 (+29 dBm); input compression P1dB (+14 dBm); conversion gain (6 dB), noise figure (12 dB) as well as LO phase noise of -111 dBc at 100 kHz offset.

The ADRF6510 is dual channel fully-differential baseband signal processing solution that integrates a matched pair of fully differential low-noise and low-distortion programmable filters and variable gain amplifiers onto a single chip. The ADRF6510 replaces complex, bulky discrete fixed function filters, saving considerable board area. The matched filter networks provide high flexibility as the corner frequency is fully adjustable in 1 MHz steps, thereby enabling wideband and narrow band support within a single radio design, a key benefit since the available spectrum and bandwidth varies across markets and regions worldwide.

The ADRF6510 VGA provides an adaptable multi-stage adjustable gain control range of 50 dB, a pre-amp prior to the filters provide a 6 dB step; while the variable gain amplifiers that follow the filter networks provide gain range of -5 dB to +45 dB. This allows the user to select and optimize the gain range for high dynamic range radios and eases the drive requirements into the analog to digital converter.

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