QUBE Servo 2 Teaching Experiment Platform

7.1 Encoder zero drift or reading jump

Phenomenon: When the motor is stationary, the position reading drifts slowly or there is a ± 1 count jump.

Solution: The encoder itself is incremental, and zero drift is usually caused by electromagnetic interference or power ripple. You can try:

Use shielded USB cables and ensure good grounding.

Add software filtering (such as moving average or first-order low-pass filtering) to the control program.

Re calibrate the zero position: Place the motor at the mechanical limit or a known angle, and press the "Reset Encoder" button in the software.

7.2 Power amplifier overheating protection

Phenomenon: After a long period of high load operation (such as frequent forward and reverse swing of the pole), the motor suddenly stops and recovers after cooling.

Solution: The built-in amplifier has overheat protection. It is recommended to let the equipment idle for 2 minutes every 15 minutes during the laboratory operation cycle. Teaching experiments usually have a low load and are unlikely to trigger protection.

7.3 Mechanical wear of swing rod module

Phenomenon: Friction or jamming occurs when the pendulum rotates around the axis, which affects the control effect of the inverted pendulum.

Solution: Remove the swing rod module and drip a very small amount of plastic grease (such as silicone grease) onto the shaft. Avoid using oily lubricants (which may corrode plastics). If the wear is severe, you can contact Quanser to purchase replacement swing rod components (or 3D print them yourself).

7.4 Regular calibration checklist (recommended once per semester)

Project methodology

Zero voltage output calibration disconnects the motor enable, and the encoder reading stabilizes at zero; Send a 0V command, the motor should not rotate.

Verify the direction of the encoder by manually rotating the motor shaft in the forward direction, and observe that the position reading should increase.

Current sensor calibration uses external precision resistance to measure the actual current, compare the feedback value, and adjust the gain in the software if necessary.

The LED color verification program displays red, green, and blue in sequence to ensure that all three channels are functioning properly.

Advanced Applications and Graduation Design Cases

Here are some graduation project topics based on QUBE-Servo 2 (already implemented by foreign universities):

Wireless control based on Raspberry Pi: Using an embedded panel, run Python+GPIO driver on Raspberry Pi, achieve remote control through WiFi, and establish a web interface to display real-time curves.

Model Predictive Control (MPC) Implementation: Design a predictive controller using MATLAB's MPC Toolbox on the USB version and compare PID performance.

Fault detection and fault-tolerant control: Artificially simulate encoder pulse loss or current sensor offset, design an observer to estimate the state and maintain stable operation.

Virtual reality interaction: Build 3D models using Unity or Unreal engines, map the actual angles of QUBE to the virtual environment, and achieve gamified control experiments.

These projects can fully exercise the engineering practice ability of undergraduate students, and the equipment cost is low (about several thousand yuan per set, far lower than industrial grade servo platforms), suitable for batch configuration in innovation laboratories.

Procurement and laboratory deployment recommendations

Quantity planning: For a class of 20 people, it is recommended to equip 10 sets of equipment (two people per group). If funds are limited, 5 sets can also be configured and used in rotation.

Interface selection strategy: Most course content (system modeling, PID, frequency domain) is suitable for USB version. If an embedded system course is offered, an additional embedded panel can be purchased (without the need to purchase a complete machine) to achieve dual-use.

Software License: The educational license for MATLAB/Simulink already includes most of the toolboxes. QUARC requires a separate license, but the academic price is relatively reasonable. LabVIEW users need to confirm whether they have purchased the RCP module.

Spare parts list: It is recommended to purchase an additional 2 sets of inertia discs and swing rods (which are prone to loss or damage), as well as 5 USB cables and SPI cables.

Cost benefit analysis: Compared to purchasing a large rotary servo test bench (such as a brand with a cost exceeding $5000), the price of QUBE Servo 2 is significantly lower (referred to as "low cost" in the original text), and it integrates amplifiers, encoders, and data acquisition without the need to purchase additional accessories. By providing free course materials, teachers can save hundreds of hours of preparation time.