On Motion of Robot End-Effector Using the Curvature Theory of Timelike Ruled Surfaces with Timelike Rulings

The trajectory of a robot end-effector is described by a ruled surface and a spin angle about the ruling of the ruled surface. In this way, the differential properties of motion of the end-effector are obtained from the well-known curvature theory of a ruled surface. The curvature theory of a ruled surface generated by a line fixed in the end-effector referred to as the tool line is used for more accurate motion of a robot end-effector. In the present paper, we first defined tool trihedron in which tool line is contained for timelike ruled surface with timelike ruling, and transition relations among surface trihedron: tool trihedron, generator trihedron, natural trihedron, and Darboux vectors for each trihedron, were found. Then differential properties of robot end-effector's motion were obtained by using the curvature theory of timelike ruled surfaces with timelike ruling

On Motion of Robot End-Effector Using the Curvature Theory of Timelike Ruled Surfaces with Timelike Rulings

The trajectory of a robot end-effector is described by a ruled surface and a spin angle about the ruling of the ruled surface. In this way, the differential properties of motion of the end-effector are obtained from the well-known curvature theory of a ruled surface. The curvature theory of a ruled surface generated by a line fixed in the end-effector referred to as the tool line is used for more accurate motion of a robot end-effector. In the present paper, we first defined tool trihedron in which tool line is contained for timelike ruled surface with timelike ruling, and transition relations among surface trihedron: tool trihedron, generator trihedron, natural trihedron, and Darboux vectors for each trihedron, were found. Then differential properties of robot end-effector's motion were obtained by using the curvature theory of timelike ruled surfaces with timelike ruling

Robots in machining

Robotic machining centers offer diverse advantages: large operation reach with large reorientation capability, and a low cost, to name a few. Many challenges have slowed down the adoption or sometimes inhibited the use of robots for machining tasks. This paper deals with the current usage and status of robots in machining, as well as the necessary modelling and identification for enabling optimization, process planning and process control. Recent research addressing deburring, milling, incremental forming, polishing or thin wall machining is presented. We discuss various processes in which robots need to deal with significant process forces while fulfilling their machining task

Impact of acute aerobic exercise on motor learning and executive function in adults with intellectual disabilities

As motor learning in individuals with intellectual disabilities (ID) has been poorly elucidated, this study aimed to apply an acute aerobic exercise (AE), well-known intervention favorable to motor learning in typically developing individuals, to assist people with ID in motor learning, and examine its underlying mechanisms via EF and EEG assessments. 17 adults with ID (11 males, aged 31.41 ± 9.7, & mental aged 7.69 ± 3.06) participated in this within-group counterbalanced study. They participated in 2 interventions, a vigorous treadmill walking (AE) or seated rest (CON) condition, with having a month of wash-out period in between interventions. The pre-test, post-test, 24-hour retention test, and 7-day retention test was administered, and each testing phase administered a golf putt performance under both original (i.e., with guideline) and transfer putt tasks (i.e., without guideline), EF (i.e., Knock and Tap test, forward and backward Digit span test, forward and backward Corsi block test), and resting EEG assessment. Golf putting accuracy in post-test was not significantly different from the pre-test; however, the putt accuracy under the transfer putt task indicated an interaction effect at 24-hour retention test phase compared to pre-test, F(1, 32) = 5.26, p = .03, ηp2 = .14, and paired t-test indicated a near significant improvement in putt accuracy in AE (p = .07), but not in CON condition (p = .23). The pre-test and 7-day retention phases did not indicate a significant effect on golf putt skill. As EF variables and resting EEG temporal alpha asymmetry (TAA) remained unchanged throughout the procedure, underlying mechanisms of change in putt skill need to be further investigated. This study revealed a trend that the AE positively influenced golf putt accuracy and offline motor memory consolidation at 24-hour retention phase, but the effects were not statistically significant. Given that the study procedure did not include practice blocks, the observed positive impact of AE on golf putt accuracy is promising; thus, a future study is recommended to further verify the benefit of AE on motor learning in individuals with ID, as well as with rigorous EF and EEG measures to elucidate possible underlying mechanisms of AE-dependent improvement in motor skill

Robot trajectory planning using the curvature theory of ruled surfaces

This dissertation is concerned with the curvature theory of a rigid body moving in three-dimensional space. While the theory is applied to robot trajectory planning, the results also provide insight into rigid body motion in general. The motion of a robot end-effector in space has six degrees of freedom, in general, and six independent parameters are required to describe the position and orientation of the end-effector. The robot trajectory, describing the motion of a robot end-effector, is represented in this dissertation by a ruled surface and an additional parameter, referred to as the spin angle. This is believed to be a more efficient approach than the conventional matrix representation which shows redundancy of parameter. A method of robot trajectory planning is proposed based on the curvature theory of ruled surfaces. The curvature theory of general and special ruled surfaces are studied. The special ruled surfaces, referred to as developables, are the cylindrical surface, cone, and tangent surface. The curvature theory is used to determine the differential properties of the motion of a robot end-effector. The differential properties of the robot end-effector motion are then related to the time-dependent properties of the motion which are essential in the robot trajectory planning. In many practical applications, a robot trajectory can not be represented by a closed-form parametric expression of a ruled surface. In this case, a geometric modeling technique, based on the Ferguson curve model, is used to generate a ruled surface. This method is incorporated into the robot trajectory planning