An overview of the space remote manipulator system

An overview of the system requirements and performance of the Shuttle Remote Manipulator System (SRMS) is given. Data on some of the mechanical design considerations that were necessary during the development program are presented. The operational success of both the Orbiter and the SRMS during flights of Space Transportation System-2, -3, and -4 is ample evidence that the SRMS performed as expected and as desired. While some minor improvements were made in the follow-on production systems, one of which was delivered and two of which are currently under construction, the system design did not change significantly. Thus, information given is applicable to all the manipulator systems

The role of the real-time simulation facility, SIMFAC, in the design, development and performance verification of the Shuttle Remote Manipulator System (SRMS) with man-in-the-loop

The SIMFAC has played a vital role in the design, development, and performance verification of the shuttle remote manipulator system (SRMS) to be installed in the space shuttle orbiter. The facility provides for realistic man-in-the-loop operation of the SRMS by an operator in the operator complex, a flightlike crew station patterned after the orbiter aft flight deck with all necessary man machine interface elements, including SRMS displays and controls and simulated out-of-the-window and CCTV scenes. The characteristics of the manipulator system, including arm and joint servo dynamics and control algorithms, are simulated by a comprehensive mathematical model within the simulation subsystem of the facility. Major studies carried out using SIMFAC include: SRMS parameter sensitivity evaluations; the development, evaluation, and verification of operating procedures; and malfunction simulation and analysis of malfunction performance. Among the most important and comprehensive man-in-the-loop simulations carried out to date on SIMFAC are those which support SRMS performance verification and certification when the SRMS is part of the integrated orbiter-manipulator system

Experimental comparison of parameter estimation methods in adaptive robot control

In the literature on adaptive robot control a large variety of parameter estimation methods have been proposed, ranging from tracking-error-driven gradient methods to combined tracking- and prediction-error-driven least-squares type adaptation methods. This paper presents experimental data from a comparative study between these adaptation methods, performed on a two-degrees-of-freedom robot manipulator. Our results show that the prediction error concept is sensitive to unavoidable model uncertainties. We also demonstrate empirically the fast convergence properties of least-squares adaptation relative to gradient approaches. However, in view of the noise sensitivity of the least-squares method, the marginal performance benefits, and the computational burden, we (cautiously) conclude that the tracking-error driven gradient method is preferred for parameter adaptation in robotic applications

Miniaturized modular manipulator design for high precision assembly and manipulation tasks

In this paper, design and control issues for the development of miniaturized manipulators which are aimed to be used in high precision assembly and manipulation tasks are presented. The developed manipulators are size adapted devices, miniaturized versions of conventional robots based on well-known kinematic structures. 3 degrees of freedom (DOF) delta robot and a 2 DOF pantograph mechanism enhanced with a rotational axis at the tip and a Z axis actuating the whole mechanism are given as examples of study. These parallel mechanisms are designed and developed to be used in modular assembly systems for the realization of high precision assembly and manipulation tasks. In that sense, modularity is addressed as an important design consideration. The design procedures are given in details in order to provide solutions for miniaturization and experimental results are given to show the achieved performances

Investigations into the design of a wheelchair-mounted rehabilitation robotic manipulator

This research describes the steps towards the development of a low-cost wheelchair-mounted manipulator for use by the physically disabled and elderly. A detailed review of world rehabilitation robotics research has been conducted, covering fifty-six projects. This identified the main areas of research, their scope and results. From this review, a critical investigation of past and present wheelchair-mounted robotic arm projects was undertaken. This led to the formulation of the key design parameters in a final design specification. The results of a questionnaire survey of fifty electric wheelchair users is presented, which has for the first time established the needs and abilities of this disability group. An analysis of muscle type actuators, which mimic human muscle, is presented and their application to robotics, orthotics and prosthetics is given. A new type of rotary pneumatic muscle actuator, the flexator, is introduced and through extensive testing its performance characteristics elucidated. A review of direct-drive rotary pneumatic, hydraulic and electrical actuators has highlighted their relative performance characteristics and has rated their efficiency in terms of their peak torque to motor mass ratio, Tp/MM. From this, the flexator actuator has been shown to have a higher Tp/MM ratio than most conventional actuators. A novel kinematic arrangement is presented which combines the best features of the SCARA and vertically articulated industrial robot geometries, to form the 'Scariculated' arm design. The most appropriate actuator for each joint of this hybrid manipulator was selected, based on the criteria of high Tp/MM ratio, low cost, safety and compatibility. The final design incorporates conventional pneumatic linear double-acting cylinders, a vane type rotary actuator, two dual flexator actuators, and stepping motors for the fme control of the wrist/end effector. An ACSL simulation program has been developed which uses mass flow rate equations, based on one-dimensional compressible flow theory and suppressed critical pressure ratios, to simulate the dual flexator actuator. Theoretical and empirical data is compared and shows a high degree of correlation between results. Finally, the design and development work on two prototypes is discussed. The latest prototype consists of a five-axis manipulator whose pneumatic joints are driven by pulse width modulated solenoid valves. An 8051 microprocessor with proportional error feedback modilles the mark to space ratio of the PWM signal in proportion to the angular error of the joints. This enables control over individual joint speeds, reprogrammable memory locations and position monitoring of each joint. The integration of rehabilitation robotic manipulators into the daily lives of the physically disabled and elderly will significantly influence the role of personal rehabilitation in the next century

On Advanced Mobility Concepts for Intelligent Planetary Surface Exploration

Surface exploration by wheeled rovers on Earth's Moon (the two Lunokhods) and Mars (Nasa's Sojourner and the two MERs) have been followed since many years already very suc-cessfully, specifically concerning operations over long time. However, despite of this success, the explored surface area was very small, having in mind a total driving distance of about 8 km (Spirit) and 21 km (Opportunity) over 6 years of operation. Moreover, ESA will send its ExoMars rover in 2018 to Mars, and NASA its MSL rover probably this year. However, all these rovers are lacking sufficient on-board intelligence in order to overcome longer dis-tances, driving much faster and deciding autonomously on path planning for the best trajec-tory to follow. In order to increase the scientific output of a rover mission it seems very nec-essary to explore much larger surface areas reliably in much less time. This is the main driver for a robotics institute to combine mechatronics functionalities to develop an intelligent mo-bile wheeled rover with four or six wheels, and having specific kinematics and locomotion suspension depending on the operational terrain of the rover to operate. DLR's Robotics and Mechatronics Center has a long tradition in developing advanced components in the field of light-weight motion actuation, intelligent and soft manipulation and skilled hands and tools, perception and cognition, and in increasing the autonomy of any kind of mechatronic systems. The whole design is supported and is based upon detailed modeling, optimization, and simula-tion tasks. We have developed efficient software tools to simulate the rover driveability per-formance on various terrain characteristics such as soft sandy and hard rocky terrains as well as on inclined planes, where wheel and grouser geometry plays a dominant role. Moreover, rover optimization is performed to support the best engineering intuitions, that will optimize structural and geometric parameters, compare various kinematics suspension concepts, and make use of realistic cost functions like mass and consumed energy minimization, static sta-bility, and more. For self-localization and safe navigation through unknown terrain we make use of fast 3D stereo algorithms that were successfully used e.g. in unmanned air vehicle ap-plications and on terrestrial mobile systems. The advanced rover design approach is applica-ble for lunar as well as Martian surface exploration purposes. A first mobility concept ap-proach for a lunar vehicle will be presented

Jump Training Analysis: An Application in Strength and Conditioning

Force development is a crucial part of sports performance. Jumping is a mechanical movement used in various sports to analyze force production. Strength and Conditioning coaches work with athletes on improving sports performance through a variety of exercises. The mechanical principles utilized in jump training will help coaches train athletes to excel. Research has analyzed the various components of jumping that could substantially improve the rate of force development. Studies about the mechanisms of jumping will consist of devices used to measure force, phases of the jump, neuromuscular control of jumping and exercises to help athletes improve. The following thesis will include a review of jumping as well as an application strength and conditioning coach’s use in the weight room

Review of employment and skills: April 2011

"This Review has its foundation in the Leitch Report published in 2006, which recommended the development of an “integrated employment and skills service to help people meet the challenges of the modern labour market” and for the UK Commission for Employment and Skills to report on the changes required to deliver integrated services. The UK Commission’s 2010-11 Grant in Aid Letter required: “The continuation of a Review that has as its focus progress on integrating employment and skills systems”. This report covers England only. There will be separate reporting for Wales and Scotland after the elections in May 2011." - Page 5