Vijaykumar, R., Waldron, K. & Tsai, M. 1986, 'Geometric Optimization Of Serial Chain Manipulator Structures For Working Volume And Dexterity', International Journal Of Robotics Research, vol. 5, no. 2, pp. 91-103.
View/Download from: Publisher's site
The interaction of the mechanics of a mobile platform with control and sensing hardware and software is important to performance in robotic applications. In this paper the basic principles involved will be reviewed, and new material on comparative characterizations will be presented. The application of those principles to a specific example: the Adaptive Suspension Vehicle, will be presented. © 1986.
A simple expert system for initial selection of bearings is described in this paper. This selection process represents a node in a design decision network, and is typical of a number of situations in which the designer must select from among diverse possibilities. The expert system is intended to be the front end of a program that includes algorithms for the sizing of bearings of selected type, and which accesses a data base of standard sizes with load life rating for those types which are available in this form. A unique feature is the way in which the rule system was generated by the expert. The expert generated a flow chart using a drafting package on a personal computer. This representation was found to be very easily converted into a rule system in the OPS5 shell. Direct generation of the knowledge base by the expert in this manner also proved to be very efficient. (A)
A series-bypass hydraulic circuit is evaluted for use on a six-legged walking vehicle. The series-bypass circuit is a hybrid circuit which combines features such as variable displacement pump control and servo control of flow bypassing actuators to achieve high energy efficiency and actuator speed of response. The circuit design relies on hydraulic coordination of the motion of multiple actuators subject to the same nominal load-flow requirements and uses digital control algorithms to accommodate deviations from the nominal requirements. A prototype series-bypass circuit is mathematically modeled and analyzed using linear dynamic models and a nonlinear time domain simulation. Controller designs selected using the analytical studies are experimentally evaluated. The experimental results confirm the behaviour and trends predicted by analysis and establish the feasibility of the proposed hydraulic circuit design.
© 1986, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. The system integration issues associated with the design of Rovers for Mars grounfi surface operations are addressed in this paper. Requirements are established for both long distance traverse between geology sites and for geologic survey operations. To satisfy these mission requirements, a semi-autonomous vehicle design has been proposed and its performance capabilities are assessed. Furthermore, the mobility, power consumption, coordination and control (maneuverability), and reliability Issues associated with the design of mobility systems to permit vehicle traverse over rugged terrain are examined and the direction of future work required to address these issues Is outlined.
A proximity sensor using a mechanical contact principle is under development for robotic applications. Good discrimination between contact loads and inertial windage loads is essential. Rugged design and easy replacement of sensing elements is also necessary. The sensor is under consideration for use on the feed of an adaptive suspension vehicle.
The design of the geometry of a walking machine depends to a considerable extent on the applications for which the machine is intended. Nevertheless, there are some very general principles and approaches which may be applied. This paper deals with the geometric design of a hexapodal walking machine which is to possess optimum mobility on varied terrain. This problem both illustrates, and serves as a vehicle for, the development of these general principles.
An algorithm for generating the workspace for manipulator geometries involving orthogonal and parallel joint axes was developed. This algorithm can handle industrial robots with revolute joints as well as with prismatic joints. In addition, a technique based on the Gaussian Divergence Theorem has been introduced for computation of workspace volume, centroid, and moments of inertia about the three principal axes. This unique technique permits a closed form, high accuracy, quantitative measurement of geometric properties. These algorithms have been implemented in an interactive computer graphic program providing an efficient method for design and evaluation of the regional structure of an industrial robot.
Six degrees of freedom is only the minimum requirement for a manipulator to have full spatial positioning capability. However, effective use of more than six degrees of freedom is not a simple problem. Those systems with redundant degrees of freedom which have been successfully operated are based on end-point sensing. The authors deal with ways of making effective use of additional degrees of freedom in conventional, open-loop, industrial-robot-type operation.
A simple expert system for initial selection of bearings is described in this paper. This selection process represents a node in a design decision network, and is typical of a number of situations in which the designer must select from among diverse possibilities. The expert system is intended to be the front end of a program that includes algorithms for the sizing of bearings of selected type, and which accesses a data base of standard sizes with load life ratings for those types which are available in this form.
A manipulator is at a singular configuration when the screws representing the instantaneous joint motions of the manipulator are linearly dependent, and the manipulator cannot be moved along an exact path with specified orientation in world coordinates. There are infinity **3 singular configurations for a six-degree-of-freedom manipulator, and all these configurations constitute the singularity field. An algorithm is derived to trace the singularity field. Another algorithm presented in this paper finds all the joint screws reciprocal to a given wrench screw. Some new robotic applications are then possible using the principle of aligning a power tool with the screw of the reciprocal wrench.