This study examines the impact of Explainable AI (XAI) on users’ cognitive and affective responses, with a particular emphasis on cross-cultural differences. Utilizing the Situation Awareness-Based Agent Transparency model, our XAI mechanisms varied in terms of transparency levels and explanation types. Survey studies conducted in the United States (N = 1200) and Taiwan (N = 600) assessed the cultural influences on XAI perception. Our findings identified significant cultural differences, with Western cultures demonstrating an increased awareness of data privacy and exhibiting a pronounced reluctance to trust AI services. The results further revealed that Eastern cultures emphasized rational analysis in evaluating privacy risk, whereas Western cultures were more inclined to employ emotional responses to assess privacy concerns. Regarding the effectiveness of XAI mechanisms, both the low system transparency with an example-based method and high system transparency with a feature-based method yielded similar positive outcomes. Additionally, while the U.S. group exhibited little variance between conditions, Taiwanese participants demonstrated heightened sensitivity to differences in XAI approaches.

Resolved acceleration motion control using the pseudoinverse or weighted pseudoinverse of the Jacobian matrix is a well-known algorithm for control of redundant robotic manipulators. Several authors have observed instabilities in simulations using this algorithm. In this paper the cause of the instability is determined, and the corresponding growth of joint velocities and acceleration is characterized in terms of the smallest singular value of the Jacobian matrix of the kinematic function, and a nearly-conserved quantity analogous to angular momentum. The analysis is supported by simulations. Based on the analysis, a stabilizing modification to the control scheme is derived that does not rely on the simple addition of a kinematic component, but rather addresses the cause of the instability directly. Simulations show that the new control algorithm stabilizes the motion in agreement with the analysis.

Solutions of the inverse kinematic problem for redundant manipulators are studied for workspace paths that pass near, but not through, kinematic singularities. Widely-used algorithms such as pseudo-inverse velocity control may compute solution paths that have low joint velocities but very high joint accelerations, which may not be physically desirable or even feasible. In this paper we show the existence of solutions with low joint space acceleration, which use the redundancy of the mechanism to track the workspace trajectory by means of a more natural joint motion. We derive a redundancy resolution algorithm at the velocity level that is computationally undemanding and tracks the desirable low-acceleration solution path. Simulations illustrating the feasibility of the proposed algorithm are presented.

The goal of this paper is to provide guidelines for the fixturing of nonprismatic workpieces based on the mechanics of frictionless contact model. Geometries of stable fixtures are studies in this analysis. Previous works on the fixturing of prismatic workpieces are extended to the fixturing of nonprismatic workpieces.

Most analyses in fixture designs are conducted for prismatic workpieces based on the assumption that the contacts between a workpiece and its surrounding fixels are frictionless. To improve on the existing analyses, the goal of this paper is to study the fixturing of polyhedral workpieces under frictional point contact and soft-finger contact models. Geometries of stable fixtures are investigated based on the mechanics of these contact models.

The extended Jacobian method is a popular approach for controlling a kinematically redundant arm which allows one to resolve redundancy by locally optimizing an objective function and to gain repeatability for a cyclic end effector trajectory. It is a special case of a family of methods called constraint function methods. It has been found that the occurrence of algorithmic singularities can cause severe difficulties and the advantages of the methods such as repeatability might no longer exist. The purpose of this paper is to study the characteristics of algorithmic singularities, especially those of corank 1. A result of the authors on kinematic singularities is used to obtain a sufficient condition for the existence of solution paths at algorithmic singularities of the constrained function method. The phenomenon of branch repeatability is shown to occur at an algorithmic singularity. We also show that the extended Jacobian method cannot successfully optimize the objective function beyond the singularity without loss of continuity of the joint derivative. Examples are given to demonstrate the use of our theoretical results.

Resolved motion rate control, which uses a linear approximation to the kinematic function to find joint velocities, can fail at kinematic singularities. Pohl and Lipkin (1991) proposed rate control using a quadratic approximation to the full kinematic function, but this algorithm has disadvantages. Here we propose a hybrid algorithm that works at singularities, is computationally efficient, and finds all physically meaningful solution trajectories. Furthermore, it is shown that this algorithm finds smoother solutions than, the damped least squares algorithm for paths passing through singular points.

A new kinematic algorithm for the control of mechanisms is described, which produces smoother and more accurate control near kinematic singularities than the usual damped least-squares method. The new method predicts the occurrence of singularities, evaluates the singular terms of the inverse kinematic function using a nonsingular expression, and smoothly interpolates between the singular and nonsingular forms. The desingularized expression makes use of the rates of change of the singular vectors and values of the Jacobian matrix; formulas for these derivatives are presented. Simulations of the control of two and six joint serial manipulators moving through and near singular configurations are given to illustrate the method.

Resolved motion rate control is an algorithm for solving the path-tracking problem in robotic control which can fail at singular points of the kinematic function. The questions of existence and smoothness of solutions to the path tracking problem at singular points have not heretofore been addressed. In this paper we find a new second-order condition which, when satisfied, ensures the existence of a solution path with continuous, bounded joint rates. The condition is related to the curvature of the path at the singular value. We prove that a modification of the usual resolved motion rate control algorithm can successfully compute this solution path. As an application, we give a sufficient condition for the existence of self-motion for redundant manipulators at singular points. We derive a simple formula for the rate of recovery of the manipulability measure near the singularity. Several realistic examples are presented, for which we compute exact solutions to typical path tracking problems passing through singular points.

The purpose of this paper is to demonstrate the importance of clamping sequences in fixturing processes. We analyze the stability of fixturing prismatic workpieces during different stages of clamping. Sequences of clamping described in this research assure the stability of the workpiece during clamping processes and relax the stringent requirement on the positioning accuracy of placing the clamps.

Resolved motion rate control is an algorithm for solving the path-tracking problem in robotic control which can fail at singular points of the kinematic function. In this paper we find a new second-order condition which, when satisfied, ensures the existence of a solution path with continuous, bounded joint rates. The condition is related to the curvature of the path at the singular value. As an application, we give a sufficient condition for the existence of self-motion for redundant manipulators at singular points. We derive a simple formula for the rate of recovery of the manipulability measure along the path at the singularity, and prove that the usual resolved motion rate control algorithm can be modified to compute these solution paths. Several realistic simulations are presented.

This paper presents an analysis on the mechanics of grasping general solid objects under frictional point contact model. Any disturbing force/moment pair at the mass center of an object can be balanced (or force-closured) if there exist a particular set of internal forces falling inside the friction cone of the contact points. Based on this principle, sufficient conditions for the geometrical properties of the contact points guaranteeing the existence of such internal contact forces are investigated.

The goal of this paper is to study the behavior of general redundant manipulators near singular configurations, and investigate the escapability of redundant manipulators at a singularity. Escapability means that the manipulator can actually reconfigure itself from a singular posture to a nonsingular posture via self-motion. Criteria for the classifications of escapable and inescapable singularities are established. Examples are given to demonstrate the use of these criteria.

A unified method for the instantaneous kinematics of redundant, nonredundant and in-parallel manipulators is developed. For redundant arms, we investigate the relationship between kinematic and algorithmic singularities when the method of extended Jacobian is used for task optimization. Under the same model, it is found that, for serial manipulators to move in a point-to-point fashion and for general motion of in-parallel manipulators, their instantaneous kinematics take a similar format as the method of extended Jacobian for redundant arms. Thus, our method of solution can be applied to these manipulators. Several features for the manipulators are demonstrated based on the concept of task separation in the row space of the Jacobian of these manipulators.>

Presents an analysis of the mechanics for multi-fingered grasps of planar objects. The main feature in the approach followed is a novel decomposition of the contact finger forces. At each grasp point, a contact force is resolved into components along the normal and tangential directions. This concept of decomposition gives deeper physical insights into the roles of the normal and tangential finger force components for multi-fingered manipulation.

Remote manipulation of objects can provide for safer construction and operations in extreme environments such as space, underwater, and disaster areas. For manipulation of objects designed for human use such as levers, handles, knobs, and so forth, a dexterous hand is desirable. Robots can be operated in remote locations as telerobots with supervision by the human operator but with a certain degree of local autonomy. This requires some intelligence at the remote site. We describe recent work related to intelligent grasping by a dexterous mechanical hand. In order to provide robot hands with intelligence required for effective multifingered grasping, a strategy of grasp reasoning is being developed to plan the grasp so that the fingers will be guaranteed to firmly grasp the object during handling and generate fine motion to perform tasks using the same planned grasp points. Grasp planning strategies based upon heuristic experiences from the motions of human hands and fingers may experience difficulties when applied to the grasp of mechanical hands and fingers due to lack of precise sensing devices. This paper proposes a planned strategy for grasping based on mechanics principles and codes the grasp mechanics into an expert system which has been applied in graphic simulation. This system can be used to reason and make decisions of grasp points on any polygonal object. This strategy has the advantages of being intelligence based and computationally efficient without sacrificing the physics of the grasp. The method will be useful in real-time applications of sophisticated robot hands by reducing the complexity both in planning and control. This system cm have applications to the grasping of objects for construction and operation by mechanical hands with semi-autonomous operations in extreme environments.