Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 79 | SUPERCAPACITOR MODULE FOR ILLINI-ROBOMASTER ROBOT |
Haoyuan You Shaurya Grover |
Matthew Qi | design_document2.pdf final_paper1.pdf photo1.jpg photo2.jpg presentation1.pptx proposal1.pdf |
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| SUPERCAPACITOR MODULE FOR ILLINI-ROBOMASTER ROBOT Team Members: - You, Haoyuan (hy19) - Grover, Shaurya (sgrover4) PROBLEM Illini-Robomaster (iRM) is an RSO at UIUC competing in the Robomaster robotics competition. During a match, robots will be punished when exceeding the power limit (80W), but the monitoring system (referee system) is only checking the power output from the battery. To maximize available power for the motors and achieve greater mobility, we need a device to store and release energy. Existing solutions are either prohibited by the competition rules, too large to fit in our mobile robot, or sold at an unacceptable price by our competitor universities. SOLUTION We propose a supercapacitor module to supply power in addition to the battery. It should be capable to store energy from the battery when the robot is running on low power and release energy when the robot needs it. Thus, we have more power available. The supercapacitor module should be controlled by the master MCU on the robot and when additional power is needed, the master MCU can control the MCU on the module to release the power. We propose two solutions: 1. The capacitor sits between the battery and the rest of the robot’s power bus. The robot is powered entirely by the capacitor and the battery only charges the capacitor. The battery, capacitor, and the robot’s power bus are interconnected with DC-DC converters. Battery = DC-DC = Capacitor = DC-DC = Motors (Robot) “=” stands for power connection 2. The battery directly connects to the power bus and the capacitor is connected to the power bus with a bi-directional DC-DC converter. DC-DC converter charges the capacitor when the battery has extra power and reverts the direction of current when the robot needs extra power. We think this is a similar case to a redundant power supply design. Battery = Motors (Robot) = DC-DC (Bidirectional) = Capacitor “=” stands for power connection We think there are advantages to the second design due to one more DC-DC in the first design introduces extra power loss. Moreover, if the capacitor module breaks in the second design the rest of the robot is left unaffected. Yet we also think the second design is more challenging to implement. SOLUTION COMPONENTS CONTROL UNIT (SAME FOR BOTH DESIGNS) MCU Control the Power unit and communicate with the master MCU on the robot through CAN or UART. Either Atmega328 or STM32F103 depending on prototype performance. Voltage and current sensor Measure the voltage and current of the capacitor to estimate the power output and report to the master MCU POWER UNIT Capacitor array (Same for both designs) The game rule restricts the maximum energy storage to be 2000J and the max voltage on the power bus is 30V, so the max capacitance is around 4.4F. We might choose a smaller value for safety concerns. There is also an unused capacitor array in the RSO, we might consider integrating it into the module to reduce cost. Design 1: { Supercapacitor charging control module Charging of the capacitor from the battery, controlled by the MCU. This might be a DC-DC converter or off-the-shelf capacitor charging control module (like BQ24640) DC-DC module Convert the output voltage to the same voltage as the power bus (24V). Consider using a buck-boost converter. } Design 2: { Bi-directional DC-DC converter Convert the voltage from the power bus to the capacitor during charging and convert the capacitor's voltage to the power bus's during discharging. Controlled by the MCU to switch between two directions. } INTERFACES ON THE TARGETING ROBOT These are not part of the module but will be integrated with the module during the competition this June: 24V M3508 motors and C620 motor speed controllers. 24V battery The module should be able to sustain the induced current from the motors and not break any device powered by it. CRITERION FOR SUCCESS - Criterion 1: The supercapacitor module must be able to store a certain amount of energy - Criterion 2: The supercapacitor module must be able to release energy - Criterion 3: The supercapacitor module can be controlled by the master MCU |
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