Advanced Engineering Forum Vols. 2-3

Abstract: Electroencephalogram (EEG) signal has conventionally been recorded with some devices, leads, an electrode cap, amplifier units, and A/D converters. The EEG signal can be contaminated by interference or sensor failures. Among the several artifact sources, an involuntary movement of patient is one of the main sources of interference in the EEG recording. The main objective of this study is to find the time of patient’s movement and to reduce noise effects from involuntary movements.

Abstract: Since brain waves are expressed in a variety of frequency domains, they were used to analyze a correlation between colors and concentration. In this study, the brain wave reacting when exposed to colors was defined as a color brain wave (CBW). Also the colors on the table were changed during task performance to see colors’ influence on improving concentration and then the brave waves were measured for analysis on and comparison with the findings from the task performance. Based on the biometric data experiment conducted, it was confirmed that the findings during the task performance and those from EEG signals have a correlation and that human’s concentration is thus affected by changes of colors.

Abstract: This paper describes the design of the cross-country robot’s control system. It mainly includes two parts, one is the software and hardware system for the lower computer, the other is the man-machine interface for the upper computer. The core of the hardware system is MCU; it controls double relays to drive the motor’s positive and negative rotations, and accordingly carries out the cross-country robot’s forward, backward and other functions. On the other hand, the upper computer uses VB to program and it uses a component named MScomm to communicate with the lower MCU via wireless COM. The double relays’ controlling motor is this paper’s innovation point.

Abstract: We made two objects (hollow metal cylinders) with identical appearance. One was called the constrained object; another was called the unconstrained object. Human subjects lifted the constrained and unconstrained objects separately for various experiment conditions. We compared human’s weight perception between the two types of objects. Results showed that weight perception between constrained and unconstrained lifting was almost the same. In our previous research, we developed a power assist system for lifting objects and determined a psychophysical relationship between actual and perceived weights for the objects lifted with the system [1]. The perceived weights were 40% of actual weights. However, the objects lifted with the system were constrained objects (as they were tied to the force sensor) that might affect the accuracy of the relationship. The results of this paper confirm that the constraint does not affect weight perception too much, which reconfirms that the psychophysical relationship between actual and perceived weights derived in our previous research was correct [1].

Abstract: We developed a 1-DOF power assist robot system to lift objects of different sizes by human subjects. We adopted a hypothesis that weight perception due to inertia might be different from that due to gravity when lifting an object with a power assist robot because the human feels a difference between the actual weight and the perceived weight of the object. We included this hypothesis in the robot dynamics. We then discussed the suitability of force control for the robot for lifting objects and developed several weight-perception-based force control strategies. These force control strategies may be compared to previously developed position control strategies, and the comparison results may help determine appropriate control for the robot to achieve desired maneuverability. The results, as a whole, may help develop human-friendly power assist devices to handle heavy objects in various industries.

Abstract: We developed a 1-DOF power assist robot to lower objects from higher position to lower position. Subjects lowered objects of different sizes with the robot and we analyzed heaviness perception, load force, motions (displacement, velocity, acceleration) etc. We determined a psychophysical relationship between actual heaviness and perceived heaviness for objects lowered with the robot system. We tried to identify some control parameters from the analytical results, and proposed them to be used to determine and develop an appropriate control scheme for power assist robots for lowering heavy objects in various industries. This paper reports the preliminary study results on this issue.

Abstract: In order to design the humanoid dual-arms high voltage transmission line inspection robot, the robot model is given and the working mechanism of the robot crossing obstacles is introduced, and the motion trajectory of the robot when it is moving is analyzed. The dynamic equations of the serial driven and the serial-parallel driven robotic arm are presented based on Lagrange equation and the dynamic characteristics of the wrist and elbow joint are simulated. The numerical simulation result of the serial driven robotic arm shows that the elbow joint has great torque when the robot moves horizontally and vertically. However, the numerical simulation result of the serial-parallel driven robotic arm shows that the elbow joint torque reduces greatly comparing with the serial driven arm. By analyzing the results of the simulation experiment, it can be seen that this serial-parallel combination driven joint with flexible-cable can reduce the elbow torque greatly and improve the load capacity of robotic arm comparing with the serial driven joint, which can solve the problem that the torque of serial driven joint in dual-arms inspection robot is too high.

Abstract: A parameter optimization method based on sensitivity analysis is presented for the structural optimization of variable section slender manipulator. Structure mechanism of a polishing robot is introduced firstly, and its stiffness model is established. Then, a design sensitivity analysis method and a sequential liner programming (SLP) strategy are proposed. In the beginning of the optimization, the design sensitivity analysis method can be used to select the sensitive design variables which can make the optimized results more efficient and accurate. And then, it can be used to improve the convergence during the process of the optimization. The design sensitivities are calculated using the finite difference method. The search for the final optimal structure is performed using the SLP method. Simulation results show that the structure optimization method is effective to enhance the stiffness of the manipulator, no matter when the manipulator suffers constant force or variable force. This work lays a theoretical foundation for the structural optimization for such manipulators.

Abstract: The research main objective was to generate a smooth cooperative rigid object transfer by a human hand and a robot manipulator mimicking the same task performs by two humans. In achieving such objective, the relationship between movement time and traveled distances of the cooperative task performed by two humans were investigated. A motion capture system was utilized to record the movement of two subjects namely, Leader and Follower during the cooperative transfer of an object using their right hands in a seated position. The cooperative task was performed in forward/backward directions relative to the Leader. The Leader informed the Follower on the onset and the terminating position prior to the execution of the cooperative task. Both subjects moved the object towards the target together. The results show a linear relationship between movement time and traveled distances. Both subjects were found to have similar relationship for the cooperative task in the same direction. In forward/backward cooperative task, the direction is not significant in influencing the relationship between movement time and traveled distances. The relationship will be tested with robotic motion in the next phase of the research.

Abstract: In the paper, a novel new gravity-constrained (GC) three-wire-driven (TWD) parallel robot is proposed. With its mechanism model, three typical kinematics analytical models, including horizontal up-down motion, pitching motion and heeling motion and their corresponding simulations are given in detail. In static analysis, the change of tensions in the wires is calculated based on previous kinematics analysis. The simulation results show the robot has good movement stability. The paper can provide useful materials to study of dynamics and control on wire-driven robot.