Structural Flexibility of Motion Systems in the Space Environment

(c) 1993 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Digital Object Identifier : 10.1109/70.258045The state-of-the-art is summarized, focusing on interdisciplinary approaches and positions, and future directions in the design, analysis, and control of lightweight robotic and telerobotic motion systems for space application are discussed. The emphasis is on providing a logical connection between the special demands of space applications and the design of the motion system. Flexibility is presented as a natural consequence of these demands. A number of technologies are relevant to extending feasible performance into regions of the design space previously avoided due to the resulting flexibility of the structures and drives. Control technology is considered foremost, but passive damping, structural materials, structural design, operational strategy and sensor technology are closely related. Numerous references are presented for those wishing to employ these technologies

Noise effect on adaptive command shaping methods for flexible manipulator control

©2001 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other worksDOI: 10.1109/87.896749Since its introduction, the command shaping method to design command shapers as robust as possible based on the has been applied to the control of many types of flexible manipu- available infonnation on a given system (e.g., expected varialators and sthe effectiveness in the vibration suppression has been tion range of the natural frequency) [11]. Unfortunately, the roverified. However, designing an effective command shaper requires a priori knowledge about the system parameters. Recently, some bustness of the shaper comes at the expense of the command efforts have been made to make the command shaper adapt to the shaper length, which means more delay in the response. Morechanges in the system parameters. In this paper, the indirect and _. over, this approach still requires a fair amount of a priori knowlthe direct adaptive command shaping methods in the time domain edge about the system parameters for proper design. The second are compared, especially in terms of the noise effect on the per- approach is to make the command shaper adapt to uncertain formance. Analysis shows that the direct approach is less sensitive . to the noise and this analytic result is verified by the proper simu- or varying system parameters. The indirect adaptive command lation. Finally, experimental results using the direct approach are shaping method has focused on the system identification either included. in the frequency domain [3], [14] or in the time domain [2], [8]

Digital Clay: User Interaction Model for Control of a Fluidically Actuated Haptics Device

To be presented at Sim2003, 1st International Conference on Computational Methods in Fluid Power Technology, November 26-28, 2003, Melbourne, Australia.Digital Clay is a novel haptics device the purpose which is to form a continuously variable surface that can be used to display shape data or accept shape input. It will be composed of a large number of small fluidic actuators and an array of MEMS micro-valves. Teams are investigating the kinematic architecture, the human interface, the control, the fluidics, and the valve design for this device. This paper describes the development of a computer model to simulate the device as well as human interaction with it via a simulated fmgertip. The model is developed for a conceptual architecture design that could be used in a future prototype wherein the surface is defined by a close-packed array of slender fluidic actuators, however other architectures are also discussed. A key element of controlling this device will be interpreting user input. Therefore the simulations presented attempt to validate algorithms for tracking the user's finger and producing variable height bosses and creases in the surface

User Interface with Multisensory Feedback for Fluid Powered Rescue Robot

Presented at the 6th FPNI – PhD Symposium, June 15-19 2010, West Lafayette, Indiana.A semi-autonomously controlled fluid-powered legged search and rescue robot is proposed as a solution to the ever-increasing demand for more versatile rescue robot technology. The success of such a robot is dependent on the existence of a user interface that optimizes the balance between user and machine decisions and provides the operator with the appropriate amount of information to soundly make such decisions. The system design, consisting of a simulation/physical robot, on-board computer, and operator interface are described. Aspects of the relation between operator input and robot motion are discussed, such as the influence of feedback on operator actions or the integration of input into semi-autonomous gaits. The basis for tests seeking to optimize the interface design is established

Optimal path planning for the motion of a wheel

©1994 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Presented at the 1994 IEEE International Conference on Robotics and Automation, 8-13 May 1994, San Diego, CA.DOI: 10.1109/ROBOT.1994.351365In this paper, the authors examine optimal path planning for the motion of a wheel which minimizes some combination of time and effort expended. Several techniques are examined but a combination of continuation and multi-dimensional Newton-Raphson shooting is shown to be effective, within limits

Recursive Algorithm for Motion Primitive Estimation

©2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Presented at the 2011 IEEE International Conference on Robotics and Automation, May 9-13, 2011, Shanghai, China.The need for knowing future manipulator motion arises in several robotics applications, including notification or avoidance of imminent collisions and real-time optimization of velocity commands. This paper presents a real-time, low overhead algorithm for identification of future manipulator motions, based on measurements of prior motions and the instantaneous sensed actuator velocity commanded by an operator. Experimental results with a human-controlled, two degree of-freedom manipulator demonstrate the ability to quickly learn and accurately estimate future manipulator motions

Modeling and Simulation of a Pneumatically-Actuated Rescue Robot

Presented at the 52nd National Conference on Fluid Power, Las Vegas, NV, USA, March 23-25, 2011.A four-legged pneumatically actuated search and rescue robot is presented as a system with potentially enhanced versatility relative to existing rescue robots. The usage of fluid powered actuation, combined with tele-operation of the robot via an operator workstation, enables the twelve degree of freedom robot to better manipulate large objects. A simulation is developed to enable ease of design variation and implementation testing in difficult virtual terrains. The simulation consists of an actuator model, modeled in Simulink, which is interfaced with an open-source dynamic simulation. The simulation calculates the robot dynamics based on actuator inputs. Where previous research has focused on the development of simulation kinematics and simple actuator models, this paper discusses development of a friction model for improved fidelity of the simulator, as well as implementation and verification in the dynamic model. The balance between model performance and the level of realism required for system development is found and discussed

A hardware-in-the-loop simulation testbed for emulating hydraulic loads representing the complete dig cycle of a construction machine

©2008 ASMEPresented at the ASME 2008 International Mechanical Engineering Congress and Exposition (IMECE2008) October 31–November 6, 2008, Boston, Massachusetts, USA.DOI: 10.1115/IMECE2008-69143A hardware-in-the-loop (HIL) simulation testbed is designed to be capable of emulating the entire domain of hydraulic workport loads incident on a test valve during normal work cycle operations of a certain hydraulic construction machine, such as a backhoe or excavator. The HIL testbed is a useful tool during rapid prototyping of control algorithms for the test valve, and for performing controlled experiments with the valve in the context of developing valve control algorithms to improve the overall energy efficiency of hydraulic systems. This paper discusses four key topics: the architecture of the real-time simulation and testbed control process, the modeling and validation of the emulated machine dynamics, the controller development for the HIL testbed, and some initial performance testing of the HIL testbed

An Excavator Simulator for Determining the Principles of Operator Efficiency for Hydraulic Multi-DOF Systems

Presented at the 52nd National Conference on Fluid Power, Las Vegas, NV, USA, March 23-25, 2011.This paper discusses an excavator simulator constructed to evaluate the effects of human-machine interfaces (HMIs) on operator productivity. Simulation allows for standardization of the machine and environment and is less time consuming and cheaper than implementing the controller on the machine. The simulator discussed in this paper includes a realistic graphical display that exceeds the current academic simulators, audio, and a new soil model that accounts for all possible trajectories of the bucket through the soil. Two coordinated control schemes were implemented on the simulator and preliminary tests were performed to demonstrate that the simulator can be used to evaluate HMIs

Sliding mode control of a non-collocated flexible system

© 2003 ASMEPresented at IMECE 2003, the 2003 ASME International Mechanical Engineering Congress and Exposition, November 16·21, 2003, Washington, DC.A new control method is developed for position tracking control of a flexible, non-collocated system. The desired trajectory is specified for the free end of a flexible beam that moves along a horizontal track actuated by a linear motor. First, a system model is reformulated based on a pendulum with stiffness and dampening. Small angle approximations are used so that a linear model can be obtained. Next, variable structure control is chosen as the control method due to its seemingly robust nature. The sliding surface and feedback gains are designed using the developed model based on literature describing various variable structure control techniques. Simulations are then conducted to verify the control method and examine its robustness. Finally, the method is implemented on an actual system using a Kalman filter to estimate the states