Short answers one sentence for each Describe the technical d

Short answers (one sentence for each): Describe the technical difficulties of peg-in-hole part assembly using a robot arm: Describe (1) mechanical method and (1) feedback control method to solve the peg-in hole assembly problem: A Stewart platform is a parallel manipulator with 6 linear actuators connecting its base and end effector. Describe how to calculate the inverse kinematics equations for a Stewart platform. List 2 advantages and 2 disadvantage of teleperated robotic minimally-invasive surgery compared to manual minimally-invasive surgery:

Solution

a)   According to our own survey, the positioning repeatability of the most accurate 6-DOF robotic manipulator in the world is ±0.010 mm . Therefore, the peg-in-hole task with clearance which is smaller than 20 m cannot be succeeded by any manipulators with conventional position control. In order to succeed the peg-in-hole task with extremely narrow clearance by the 6-DOF robotic manipulator, a new automatic precise mating and insertion method would be necessary

b) Mechanical method ; Whitney gave kinematic analyses of the peg-in-hole problem and proved that the jamming and wedging could be avoided by placing the compliance center at or near the tip of the peg

Feedback control method ; using force feedback control, has also been studied extensively. The first interaction control of manipulator was given as hybrid position/force control . How to apply the hybrid control to a peg-in-hole problem was introduced in detail in . Then the impedance control, which enables a robot manipulator to maneuver in a constrained environment maintaining adequate contact forces, was proposed.

c) The inverse kinematics problem is almost trivial for parallel manipulator such as hexapod and is extensively used in many methods. Inverse kinematics will be presented for two different hexapod structures: standard Stewart platform based manipulator and discussed in previous sections, and hexapod. First hexapod model can be defined in many ways but most common set of parameters are: minimal and maximal struts length (lmin, lmax), radii of fixed and mobile platforms (r1, r2), joint placement defined with angle between closest joints for both platforms ( j, q) and joint moving area (assuming cone with angle y). From those values are then calculated values for ai r and bi r which are used in calculations.

d) In teleoperated robot-assisted surgery, the patient benefits from the advantages of minimally invasive surgery, such as smaller scars and shorter recovery time, compared to open procedures. In addition, surgeon performance is through to be enhanced by the robot’s high dexterity and precision inside the patient\'s body, as well as improved ergonomics.

A major problem encountered by otherwise experienced and skilled cardiac surgeons in performing fine suture manipulations with robot-assisted surgical systems is excessive suture breakage, particularly during knot tying. Our first goal was to determine whether the lack of haptic feedback played a role in this problem. Therefore, we began characterizing the forces that should be applied to various grades of suture materials. We analyzed the suture forces applied during the first throw of a suture knot. A tension measurement device was constructed to sense left- and right-hand suture tensions.