Motion Control

Designing a Multi-Segmented Robot for Hull Climbing

The Multi-segmented Magnetic Ro bot (MSMR) project addresses a capability gap in the intelligence, surveillance, and reconnaissance needs of the U.S. Navy visit, board, search, and seizure (VBSS); Navy SEALs; and Marine Force Reconnaissance teams. A segmented robotic platform with magnetic wheels and a minimal acoustic signature was developed that can navigate the hull, tanks, and passageways of a ship. The goal was to provide effective climbing and turning ability over and within a ferrous hull that typically features plumbing, protrusions, and indentations such as weld seams where hull plating meets. Such a robot will be able to climb the hull of a ship, provide covert perch-and-stare surveillance of the deck area, and wirelessly transmit audio/video before a search team boards. The technology is also promising for inspection of tanks, and dangerous or hard-to-reach passageways and voids in maritime vessels.

Posted in: Articles, Motion Control, Robotics, Inspections, Marine vehicles and equipment, Military vehicles and equipment

Moving Magnet Voice Coil Actuators Offer Controllable Movement for High-Duty-Cycle Applications

There are two types of voice coil actuators: moving coil and moving magnet. The materials of construction are similar, since they both use rare earth magnets, steel, copper wire, and basic insulation materials. There is a tendency to want to say one type is better suited for certain applications; however, there are many different sizes and shapes of voice coil actuators, making it difficult to make blanket statements about which type of actuator works better, and where.

Posted in: Articles, Motion Control, Sensors and actuators, Copper, Insulation, Steel

Optimizing Closed-Loop Control in Hydraulic Motion

Performing closed-loop control of hydraulic servo systems is often more challenging than controlling servomotor systems. The main reason is that hydraulic systems use compressible oil to move the actuator. Because of this, a hydraulic system can be modeled as a mass between two springs, where the piston and the load is the mass, and the oil on both sides of the piston represents the two springs. In contrast, servomotor systems are easier to control because there is basically only the inertia of the motor and the connected load to be dealt with.

Posted in: Articles, Motion Control, Vibration, Hydraulic systems

Robotic Exoskeleton Vastly Improves Quality of Life

Worldwide an estimated 185 million people use a wheelchair daily. A company based in Auckland, New Zealand, has developed an innovative robotic technology that helps people with mobility impairment get back on their feet— the Rex Bionics robotic exoskeleton. Its integrated maxon motors help to ensure smooth limb movement.

Posted in: Features, MDB, Articles, Electronics, Power Management, Power Supplies, Manufacturing & Prototyping, Mechanical Components, Implants & Prosthetics, Medical, Orthopedics, Rehabilitation & Physical Therapy, Motion Control, Motors & Drives, Positioning Equipment, Power Transmission, Sensors, Kinematics, Medical equipment and supplies, Robotics, Electric motors, Biomechanics

Feedback Sensors Keep Servomotors on Target

Fundamentally, a servo system can perform no more accurately than the accuracy of the feedback device controlling it. In addition, errors in speed or position can be introduced into the system by the less-than-perfect mechanisms that transfer the motor power to the load. Environmental factors like electrical noise or temperature may also introduce positioning errors. Sometimes the errors are acceptable. More frequently, however, they are not. When it comes to high-performance servo applications, feedback devices fall into several different categories. Each offers unique advantages and disadvantages, both electrical and mechanical, that make one better suited for a particular application than another.

Posted in: Articles, Motion Control, Failure analysis, Sensors and actuators, Noise, Auxiliary power units

Handling Delicate Materials

Special care needs to be taken when handling delicate materials used in medical applications. Small diameters provide increased flexibility needed for long-flex-life applications such as cardiac catheter wires. Many other applications also use these fine materials as winding and braiding materials, including the medical device industry, microelectronics, and composites.

Posted in: Articles, Motion Control, Microelectromechanical devices, Medical equipment and supplies, Materials handling, Fibers

Real-Time Software Enables Multi-Core PCs for Industrial Automation

As early as 25 years ago, industrial system integrators saw the great potential that the Windows operating system brought to PCs. They saw the possibility of using the advanced graphic capabilities that Windows offered versus the relatively primitive human interfaces of DOS-based applications and those of other proprietary OSes. Windows enabled the development of controllers with advanced human-ma chine interfaces (HMIs) that provide a whole new level of functionality, and make machines easier to use and maintain.

Posted in: Articles, Motion Control, Computer software and hardware, Human machine interface (HMI), Automation, Industrial vehicles and equipment

Using Source Measure Units to Characterize High-Power Semiconductors (Part 1)

The proliferation of electronic control and electronic power conversion into a variety of industries (e.g., energy generation, industrial motor drives and control, transportation, and IT) has made efficient power semiconductor device design and test more critical than ever. To demonstrate technology improvements, new device capabilities must be compared with those of existing devices. The use of semiconductor materials other than silicon demands the use of new processes. To be sustainable, these new processes must be tuned to deliver consistent results and high production yield. As new device designs are developed, reliability measurements must be performed on many devices over long periods. Therefore, test engineers must identify test equipment that is not only accurate, but scalable and cost-effective.

Posted in: Articles, Motion Control, Semiconductor devices, Test equipment and instrumentation, Test procedures

Linear Guide Systems Streamline Aircraft Seat Assembly and Operation

Linear guide rails are an important component within aircraft interiors. Following are some of the places where they are used:

• For seat adjustments — forward and back seat movements, footrests, sliding armrests, and tables. • Rails enable 180° positioning for super first class seats that flatten for sleeping. • Sliding privacy screens between passengers. • Kitchen slide-outs, such as garbage compactors. • Sliding lavatory doors.

Posted in: Articles, Motion Control, Seats and seating, Assembling, Aircraft

Robotic Accuracy Improves Aerospace Manufacturing

Where accuracy is concerned, robots have traditionally relied on repeatability. In the past, robotic accuracy has not been developed to a level of maturity acceptable to standard production processes. Critical aerospace manufacturing techniques such as fastening and drilling were historically not held to tight tolerances. Typical tolerances for airframe assembly fastening were in the +0.030" range. The standard is set by the positional requirement for drilling of fastener holes, which is a key target application for robotics in manufacturing.

Posted in: Articles, Motion Control, Drilling, Fastening, Robotics, Quality standards

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