Huang, MZ & Waldron, KJ 1989, 'An Efficient Rate Allocation Algorithm in Redundant Kinematic Chains', Journal of Mechanisms, Transmissions, and Automation in Design, vol. 111, no. 4, pp. 545-554.
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This paper addresses a basic problem which arises in the coordination of serial chain manipulators, namely, that of decomposing a given end effector velocity state into a set of joint rates. Such a problem is indeterminate for manipulators with kinematic redundancy. A novel method of solving the rate distribution problem for the class of fully revolute-jointed, serial manipulators is developed. The technique is an extension of the axial field solution scheme developed initially for solving the force allocation problem in a statically indeterminate parallel chain system. The basis of the solution method lies in the dualities of velocity and force systems between series and parallel mechanisms. The method offers an efficient means of rate coordination and is especially useful in the control of manipulators with high degrees of redundancy. Two examples have been given for illustration. It is shown that the minimum norm solution, obtainable commonly from pseudoinverse, can also be achieved using this new efficient algorithm.
Kumar, V & Waldron, KJ 1989, 'Actively Coordinated Vehicle Systems', Journal of Mechanisms, Transmissions, and Automation in Design, vol. 111, no. 2, pp. 223-231.
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The use of independent actuation of suspension and locomotion degrees of freedom offers significant potential for improved performance vehicles. In this paper, the mathematics of active coordination of such systems is explored. Two different, actively coordinated mobility system configurations are used as examples to elucidate the principles involved.
Kumar, V & Waldron, KJ 1989, 'Suboptimal algorithms for force distribution in multifingered grippers', IEEE Transactions on Robotics and Automation, vol. 5, no. 4, pp. 491-498.
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Kumar, VR & Waldron, KJ 1989, 'Adaptive gait control for a walking robot', Journal of Robotic Systems, vol. 6, no. 1, pp. 49-76.
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AbstractWalking vehicles have the potential to emulate the superior offâroad mobility of biological systems. However, it is important to make the walking machine terrain adaptive and versatile, and to minimize man's role as an operator in order to realize this potential. Terrain adaptive locomotion involves intelligent foothold selection and the control of gait to produce the desired motion. This requires a departure from the idealized, structured stepping patterns for statically stable gaits which have been the object of considerable research. A modifiedwave gaitis used to demonstrate that it is possible for the vehicle velocity to be varied continuously in accordance with higher level commands even with irregular, asymmetric, and changing support patterns, A varying duty factor is employed to enable optimal leg cycling frequencies. Implementation of gait control algorithms and results from a computer simulation are also presented.
Waldron, KJ, Raghavan, M & Roth, B 1989, 'Kinematics of a Hybrid Series-Parallel Manipulation System', Journal of Dynamic Systems, Measurement, and Control, vol. 111, no. 2, pp. 211-221.
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In this paper we first derive the coordinate transformations associated with a three-degree-of-freedom in-parallel-actuated micro-manipulator. Then we combine these results with the transformations associated with an in-series three-axis wrist on which the in-parallel micro-manipulator is mounted. The results are the basic transformation equations between joint-space position variables and end-effector (or task space) position variables for a hybrid series/parallel six-degree-of-freedom manipulator system. This structural combination results in a manipulator which exhibits desirable fine and gross motion characteristics as both a stand-alone device or as a sub-system of a more complex system with redundant degrees of freedom. The forward and inverse position kinematics and rate and force decomposition for this hybrid six-degree-of-freedom linkage are presented.
Stauffer, LA & Slaughterbeck-Hyde, RA 1970, 'The Nature of Constraints and Their Effect on Quality and Satisficing', 1st International Conference on Design Theory and Methodology, ASME 1989 Design Technical Conferences, American Society of Mechanical Engineers.
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Abstract A taxonomy of constraints is presented based on design considerations, source, context, strength, and use. The taxonomy is developed from observations of two sets of real-time protocol data of mechanical designers, along with the work of other researchers. The taxonomy begins to explain the nature of constraints. A hypothesis of how introduced constraints affect design quality is also presented. Finally, a more specific definition of satisficing is developed based on an experiment demonstrating constraint satisfaction.
