Joint actuated

Modeling of a human body with the emphasis to the extremities is the prerequisite for the synthesis of analytic control [3(U33]. Human extremities are unlike any other plant encountered in control engineering especially in terms of joints, actuators, and sensors. This fact must be kept in mind when applying the general equations of mechanics to model the dynamics of functional motions. A simple extension of analytical tools used for the modeling of mechanical plants to the modeling of biomechanical s) tems may easily produce results in sharp discrepancy to reality. 

Ebefors, T, J.U. Mattsson, E. Kalvesten, and G. Stemme. 2000. A robust micro conveyer realized by arrayed polyimide joint actuators. / Micromech Microeng 10 337-349. 

Given the p sent state of the manipulator, q and q, the input joint actuator traques and forces, r, and the motion of the base, the open-chain term, ijopen. is completely defined. An appropiate Direct Dynamics algorithm for < )en-chain manipulator may be used to detomine its value. With the same givoi information, the coefficient of f in the constrained term, G, is also known. The efficient computation of G was discussed in Chapter 4. 

The polyimide V-groove joint actuator has been developed for walking microrobot applications but also for use in... 

Two pairs of muscles acting around the hip and knee joints actuate the leg. The torque acting at the thigh and shank is linearly related to the joint torque (Equation 24.9) ... 

In step 2, the maximum allowed velocity in Cartesian space is limited by the maximum angular velocities of the three joint actuators. Obviously the cut-off frequency should be bounded by the resonance frequency. Since the maximum velocity and a cut-off frequency can also define the maximum acceleration, a lower cut-off frequency should be selected if joint actuators cannot reach that acceleration. 

By the Lagrange-Euler equation of motion, the required torques 4(k) of the joint actuators of robot i can be calculated [4], The required torque of joint j of robot i must satisfy... 

Pie2oelectric materials are used in many different types of sensing—actuating devices. A few appHcations include printing, monitoring of performance behavior of adhesive joints, and intelligent processing. 

In addition to the circuit breaker, there have been a number of other SMA appHcations for various functions in electric power generation (qv), distribution, and transmission systems. One such device is a thermal indicator that provides a signal visible from the ground of a hot junction or connector in a distribution yard. Such hot spots occur as a result of the loosening of bus bar connectors owing to cycHc temperature as the electric load varies. In addition to the use of SMA flags as a hot-spot indicators, actuators that automatically maintain the contact force in a bus bar connection have been demonstrated. Based on a BeUeviHe washer fabricated from a Cu—Al—Ni SMA trained to exhibit two-way memory, these washers, when heated by a hot joint, increase their force output and correct the condition. A 30 mm diameter washer 3 mm thick can produce a force of over 4000 N. Similar in purpose... 

It is convenient to measure out the hydrogen peroxide by a 10-ml. graduate or by a 10-ml. pipet actuated by a glass syringe connected via a ground-glass joint. 

Improved slide valves can lead to a more reliable FCC operation. Better actuators provide a more rapid response to process changes and can prevent unnecessary unit trips. Changing the internals to allow the valves to operate in the desired 35-65% open range gives better control and reduces wear. Expansion joints can be updated with better metallurgy and dual plys with leak detectors can be used. This can help avoid a shutdown and improve both safety and reliability. 

Each of the industrial robot elements is linked to one another by linear guides and revolute joints in a kinematic chain, and the actuation of these elements forms the axes of the robot. Kinematics is the spatial allocation of the movement axes in order of sequence and construction. 

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