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Introduction

An obvious control assignment is balancing. This assignment will focus on control tactics, which enable the pendulum to balance in a vertical position when the arm is maintained at the desired position. In order to establish the energy-based control such that the pendulum swings in a vertical direction, the control VI will be swang by the QNET rotary pendulum trainer. The QNET rotary pendulum trainer also swings up the state-feedback controller such that the pendulum is balanced when it assumes an upright position.

The presence of the grinding within the motor always makes the arm of the pendulum to sway around the reference, specifically when the pendulum is adjusted in a given point. The rubbing will cause the motor to stop moving. This will persist up to the point when the control signal is extensive enough and the torque produced exceeds the friction, thus suggesting that the pendulum is ready to fall at a particular point before the movement of the motor. The net outcome for this is a movement, which is wave-like. In the voltage function of the DC motor, a Dither sign is used to represent friction, as shown below;

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paraphrasing only  1refers to the voltage amplitude,

paraphrasing only  2represents the sinusoid frequency,

paraphrasing only  3represents the signal’s offset voltage

The following task focuses on the manner in which high-recurrence excitations affects the motions, which are activated through contact. This high-recurrence excitations are usually referred to as Dither Signals.

In order to evaluate the outcome, the employment of Simulation loop is necessary in the experiment. The re-enactment graph is executed by the Simulation loop up to the point where the recreation last time is attained by the Control & Simulation Loop. The execution of the re-enactment graph can also stop when it is stopped automatically by the Halt Simulation capacity. The simulation capacities should be placed within a Control & Simulation Loop. They can also be placed within a re-enactment subsystem. The recreation subsystems can also be placed in a Control & Simulation Loop or in any other reenactment subsystem. Another alternative is placing the reproduction subsystems on a square outline, which is not within a Control & Simulation Loop. The recreation subsystems can also be operated as stand-alone VIs.

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The circuit has the output and input nodes as depicted in the above diagram.

It is arranged within the simulation loop. It also has the necessary parameters for Signal Generators, Swing-up Control parameters and Balance Control Parameters.

Schematics & Procedure

  1. )is chosen.Device Make sure the correct Open the QNET_ROTPENT_Swing_Up_Control.vi (

  2. Run the QNET_ROTPENT_Swing_Up_Control.vi.

  3. section set:Signal Generator In the

  • Amplitude = 0.0 deg

  • Frequency = 0.10 Hz

  • Offset = 0.0 deg

  1. section set:Balance Control Parameters In the

  • kp_theta = -6.5 V/rad

  • kp_alpha = 80 V/rad

  • kd_theta = -2.75 V/(rad/s)

  • kd_alpha = 10.5 V/(rad/s)

  1. section set:Swing-Up Control Parameters In the

  • mu = 55 m/s2/J

  • Er = 20.0 mJ

  • max accel = 10 m/s2

  • Activate Swing-Up = OFF (de-pressed)

  1. scope scales to see between -250 and 250.Angle/Energy (deg/mJ) Modify the

  2. section changes to bright greenControl Indicators At this point, the LED in the In Rang. Manually rotate the pendulum in the upright position until the

  3. scope.Angle/Energy (deg/mJ) response in the Arm Angle (deg) Vary Offset and observe the

  4. scope.Angle/Energy (deg/mJ) responses in the Pendulum Angle (deg) and the blue Arm Angle (deg) When balancing the pendulum, describe the red

  5. section set:Signal Generator In the

  • Amplitude = 45.0 deg

  • Frequency = 0.10 Hz

  • Offset = 0.0 deg

  1. Clicking the stop button will make the VI to stop running.

Designed balance controller parameters:

  • Amplitude = 45.0 deg

  • Frequency = 0.20 Hz

  • Offset = 0.0 deg

Balance Control with Friction Compensation parameters:

  1. Signal generator

  • Amplitude = 0.0 deg

  • Frequency = 0.10 Hz

  • Offset = 0.0 deg

  1. Dither Signal

  • Amplitude = 0.00 V

  • Frequency = 2.5 Hz

  • Offset = 0.00 V

Results and Discussions

could not be set very high to avoid the motion of the pendulum arm to be interfered with the encoder cable. OffsetEven though several challenges were faced when undertaking the experiment, Standard process was obeyed. For example, step 7 required us to make sure that the motion of the pendulum arm is not interfered with by the encoder cable throughout the experiment. Also, in step 8, as a requirement in the standard procedure, the

The diagrams below illustrate The QNET_ROTPENT_Swing_Up_Control.vi, as well as the simulation loop.

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Some of the questions that came up while undertaking the experiment are answered below.

While at the eighth stage, we realized that varying the offset caused the arm angle to change too. That is, an increase in the offset resulted in the increase of the arm angle.

While at the ninth stage, we realized that in order to attain an effective balancing, the blue Pendulum and the red Arm should make the arm angle firm.

At first, the application of square wave to the arm angle would make the arm go in the wrong direction. This is since the arm has to resist the inertia force, and the angle needs to stabilize.

Conclusion

In conclusion, the pendulum managed to balance finally when the correct parameters were used, and the offset adjusted. By using the Dither signal in assembling the friction’s controls illustrated that Dither is necessary in eliminating friction in many situations. However, in few instances, the stable signal can destabilize Dither.