Results of the roct method in 5 the state feedback

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The manipulator with a flexible forearm. results of the ROCT method. In § 5, the state feedback control law and hybrid control law are discussed and the experimental results are given. The conclusions are presented in §6. 2. Experimental setup This section provides a brief description of the experimental setup. The objective of this paper is to present experimental results on the position and vibration control of the end- effector of a 2-DOF manipulator with a flexible forearm. Figure 1 shows a picture of the manipulator in the experimental facility. The manipulator is a 2-DOF parallelogram design similar to the one developed by Mills & Lokhorst (1993). The last link (forearm) of the robot is flexible. It operates in the horizontal plane and is driven by 2 Dynaserv direct-drive brushless motors so that the problem of friction and backlash are minimized. The characteristics of the motors used in the experimental robot are shown in table 1. Note that the motors have high performance, high torque output which prevents saturation, and high precision encoder resolution. The servo drivers for the motors can be preset to operate in 3 modes of control, namely, position control mode, speed control mode and torque/current control mode. In this experiment we preset the operation of the servo drivers to the torque/current control mode. Thus a voltage between -8 V to 8V applied to the servo drivers allows the motor to produce a torque between negative maximum torque and positive maximum Table 1. Motor characteristics. Motor model Feature Unit DM 1200A DM 1045B Maximum output torque Nm 200 45 Rated speed rev/s 1.0 2.0 Encoder resolution p/rev 1024000 655360 Weight kg 29 9.5 Rotor inertia kgm 2 0.167 0.019
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502 Koh Tuck Lye et al LED targe 5 \ sensor head (camera) ............................................................. Figure 2. Schematic diagram of an active type PSD. torque, and the voltage-to-torque relationship is linear. Thus direct torque control is achieved. In this experiment, measurement of the vibration at the end-effector of the robot is essential. The Hamamatsu C2399-00 position-sensitive detector (PSD) is used for this purpose. This is an active type, opto-electric position sensing unit which measures the position of a single-point of light spot focused on the sensor head. It uses an infrared LED mounted as a target at the tip of the flexible link and the movement of the LED is measured by a sensor camera which is mounted as shown in figure 1. Figure 2 shows the schematic diagram of the active type PSD used in the experiment. The advantage of the C2399-00 PSD is that it uses a non-discrete, silicon PSD for two-dimensional position sensing. The non-discrete nature of the PSD allows for high accuracy measurement of position. The LED is pulse-modulated and optically filtered in the sensor head with a built- in background-light cancellation circuit, making accurate measurements possible even in bright locations. Since it does not require scanning, it provides good speed of response.
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  • Fall '19
  • Koh Tuck Lye

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