Robotic vehicles have a wide field of applications in the civilian and military industry including manufacturing, assembly lines, security, operation in hostile environment, and testing. In the defense area, robotic vehicles have the potential for force multiplication and removing the soldier from hazardous environments on the battlefield. To make such vehicles avaialable requires research, development, testing and demonstration of advanced robotics and artificial intelligence (AI) technologies and systems. A realistic effort towards that objective requires the establishment of an advanced laboratory responsible for evaluation and development of subsystems and integration of the various elements into vehicles for field tests. Hence, requirements for the laboratory are given including a layout design and link analysis of the different components. As the first part of planning the laboratory, the technology was assessed to assure inclusion of the state-of-the-art equipment. Then, equipment requirements were defined, including interactions between pieces of equipment and providing for support, recording and monitoring equipment.

This paper examines a tactile slip sensor based on photoelastic effects. Photoelastic patterns are obtained using a Dynamic Ram with a resolution of 256 by 128 pixels. Software is developed to detect changes in the stress patterns when an object moves relative to the surface of the sensor. It is suggested that the stress patterns can be used to detect slippage at the object/gripper interface.

The problem of constructing a smooth path with respect to time through N given points in configuration space is considered. Two variants of an algorithm suggested by Paul are presented and evaluated. It is shown that the algorithms suggested in this paper yield in general considerable improvements in two respects: Firstly, the deviation of the resulting path from the given points is reduced markedly and secondly, the overall time needed for the movement is reduced significantly and consequently, is closer to the true minimum-time. The price to be paid for these improvements is a moderate increase of computation time allowing still online use of the algorithm.

An active force control system for robotic deburring based on an active end effector is developed. The system utilizes a PUMA-560 six axis robot. The robot's structural dynamics, positioning errors, and the deburring cutting process are examined in detail. Based on ARMAX plant models identified using the least squares method, a discrete PID controller is designed and tested in real-time. The control system is shown to maintain the force within l N of the reference, and reduce chamfer depth errors to 0.12 mm from the 1 mm possible without closed-loop control.

A parameter optimization approach to the time-minimization of robotic motions along specified paths is presented for the case when: (i) the velocity profile is a prescribed sequence of constant acceleration/deceleration segments with unspecified, but bounded vertex velocities at given path stations; (ii) the relative robot/path location can be varied. Such optimizations occur when technological requirements impose a certain velocity profile along the path due to velocity and acceleration constraints. Full nonlinear manipulator dynamics and path parameterization are used to determine the optimal velocity profile and robot location consistent with the actuator/configuration limitations. No numerical integration or search for switching curve are involved in the solution. Examples of time-and-location optimized robotic motions with specified velocity profile are presented.

This paper presents a linearization by static feedbacks in the robotic field, i.e. by feedback depending on the whole state space. A phenomenological approach is considered, which by using the derivation with respect to time, leads to the major results of the method. Simulation results are presented, and some aspects of the correction of the effect of the characteristic numbers are also discussed.

This paper presents a particular architecture of a parallel robot which is characterized by a diagonal stiffness matrix. This result suggests the use of a parallel robot in the final phase of insertion as a passive compliance device. The stiffness rate of this device is controlled by the gain of the feedback loop. As the correction of small angular misalignments due to contact forces do not generate lateral errors and vice versa, we have the equivalent of an isoelastic swivel.

Accurate modeling of robot dynamics is a prerequisite for the design of model-based control schemes and enhancement of the performance of the robot. The dynamic parameters associated with a pseudo-inertia matrix are often difficult to identify accurately because the inertia torques are small in comparison to gravity loadings, thus creating signal processing problem. The identification method presented in this paper utilizes a balancing mechanism which increases the estimation accuracy of the dynamic parameters. The balancing mechanism has the effect of amplifying the inertia-related torque signal by eliminating gravity loadings acting on the robot joints. A series of motion data were experimentally obtained through sequential test steps. By incorporating the measured information about joint torques, angular positions, velocities and accelerations the least square algorithm was used to identify the dynamic parameters. The estimated values were converted to those of the original robot model to obtain its dynamic model parameters. The identified robot dynamic model was shown to be accurate enough to predict the actual robot motions.

Studies are the effects of joint flexibility on the dynamic stability of a one-link force-controlled manipulator. The closed-loop dynamic equation with the explicit force controller and the damping force controller are first derived. Stability analysis is then carried out by computing the system eigenvalues. Results indicate a conditionally stable system. Due to the presence of discontinuous contacts with the environment during the interaction process, the system exhibits a stable limit cycle when the force feedback gain goes beyond the critical value.

To derive the equations of motion for a multibody system using the Gibbs-Appell calculus – the partial derivatives of the Gibbs function G = 1/2 ∫ a2 dm with respect to the generalized accelerations equal the generalized forces-shows special advantages. Describing the kinematics with Jacobi matrices and local terms, these equations can be written in such a way that the partial derivations need not be performed explicitly. Kinetic effects of fast rotating driving devices attached to the moving links can be included in a similar way. Though an analytical formulation of the equations of motion is especially desirable with respect to its application for industrial robots, such a formulation becomes too extended and susceptible to errors for systems with more than 3 or 4 bodies. Therefore an approach is developed for tree structured robots with rotational or translational joints for calculating the Jacobi matrices and the local terms without employing any differentiation process. So it is possible to use the Gibbs-Appell method numerically in a recursive way e.g. for calculating the torques of the actuators of a robot with 6 or more degrees of freedom for a given motion.

The stability analysis of active spatial mechanisms comprising both powered and unpowered joints is carried out for the first time using aggregation-decomposition method via Lyapunov vector functions. This method has already been used for analysis of mechanisms with all powered joints. To extend the application of the method to the stability analysis of mechanisms containing unpowered joints we developed modelling of special subsystem consisting of one powered and one unpowered joint. Then, we consider the stability of the complete system without neglecting any dynamic effect. The stability analysis is demonstrated by a numerical example of a particular biped system.