Current TRL: 3 (9/21/21)
“Different parts of CarMan have been tested to slightly different degrees, but the majority of sub-boards have been manufactured but not tested in a lab. To get to level 4, we would need to complete testing on all of the boards in the lab.”
Exploded view of CarMan enclosure
CarMan is comprised of four boards designed to handle a multitude of tasks. The GLV (Grounded Low Voltage) board provides low voltage power to various subsystems within the vehicle. LOGIC houses 2 computers that acquire and display data, control the cooling system, and determine when the car is able to drive. The TSI (Tractive System Interface) board houses parts of the shutdown circuit, isolate high voltage signals that are passed onto LOGIC and controls relays that determine the pre-charge and discharge of the motor. The Relay board delivers the high voltage from the battery packs to the motor.
- CarMan GitHub (Link)
- CarMan Lab Inventory (PDF) (Last Updated: 3/1/21)
- CarMan ICD & Wiring Table (PDF) (Last Updated: 4/19/21)
- CarMan 2022 Mid-Year Poster (PDF) (Last Updated 12/13/21)
The Car manager performs many essential functions for the safe operation of the car. It houses important subcomponents such as the motor controller, logic board, and tractive system interface. Additionally, it isolates the low an high voltage circuits within the car while allowing them to exchange information, and actively monitors the state of insulation. These essential tasks and the components chosen to perform them are described further in the full review.
Link to full document.
Codes and Standards
The only codes that apply to the car manager are those outlined in the rules.
Metrics and Constraints
Carman must maintain galvanic isolation between TSV and GLV.
EV3, EV4, EV5, EV6, EV7, EV8, EV9, EV10, EV12
The safety loop runs through most of the sub-boards in CarMan and many other panels on the car. It is responsible for keeping the S.S.OK lights lit while the system is safe and shutting down the system if a fault occurs or an emergency stop button is pressed.
Safety Loop Documents
- Safety Loop Diagram v. 12.5.1 (PDF) (Last Updated: 4/20/21)
- Safety Loop Test Results/Procedure:
- Safety Loop Demo: (Video) (Last Updated 5/18/21)
The TSI board is partitioned into two sections, TSV (Tractive System Voltage) and GLV (Grounded Low Voltage). Isolators are used to pass signals between both sections while keeping them galvanically isolated. The TSV part of the board communicates and passes signals to the pre-charge relay, the discharge relay, a bus bar current sensor, the motor controller, and the motor itself. The GLV part of the board receives 24V from the GLV BOB and passes them to other systems such as dashboard, battery packs cooling, IMD, and braking. The GLV section of the board is also responsible for the routing of the safety loop and its requisite signals.
- TSI Rev. 6 BOM (PDF) (Last Updated 5/18/21)
- TSI Rev. 6 Test Plan v. 1.4 (PDF) (Last Updated: 5/14/21)
- TSI Rev. 6 Stadium Mill Drawing (PDF) (Final Updated: 5/10/21)
- TSI Rev. 6 Stadium Mill Drawing (Inventor on Drive) (Final Updated: 5/10/21)
- TSI Rev. 6 Maintenance Manual (PDF) (Last Updated 5/18/21)
- TSI Rev. 6 Errata (Word)(PDF) (Last Updated: 12/9/21)
- TSI Rev. 6 Spring 2021 Status of Precharge Control (Video) (Last Updated 5/18/21)
- TSI Rev. 6 Fixed Precharge Test Results (Drive) (Last Updated 10/14/21)
- TSI Design Archive (LINK)
The GLV system provides low voltage power to the FSAE car. It consists of a 24V LiFePO4 battery and a breakout board (BOB). The BOB connects directly to the battery and provides breakered power to the TSI and Logic boards, cooling system, battery packs, and lights on the dashboard. The BOB also measures and reports GLV voltage and current usage to the SCADA system. The PCB is housed on the top shelf of the CarMan enclosure.
GLV BOB Documents
- GLV Design Archive (Link)
The relay board is located in the high voltage region of the CarMan enclosure. It is used to create the current path from the battery packs to the motor controller, which then powers the motor. Relays on the relay board such as the pre-charge relay are controlled by the TSI board that operates in compliance with the rule. Besides that, the TSI board also measures high voltage current and HV+ / HV- / MC+ differential voltages from the relay board.
Relay Board Documents
- Relay Board Electrical Drawing (PDF) (Last Updated: 03/21/2021)
- Assembly Drawing For Relay Board (PDF) (Last Updated: 2/24/2021)
- Base Plate Drawing (PDF) (ZIP) (Last Updated: 2/24/2021)
- Assembly Drawing For Garolite Spacers (PDF) (Last Updated: 2/24/2021)
- Short Garolite Spacer For HV+ Bus Bar v2 (PDF) (Last Updated: 2/24/2021)
- Tall Garolite Spacer For HV- Bus Bar v2 (PDF) (Last Updated: 2/24/2021)
- Garolite Cover For Relay Board Plate (PDF) (Last Updated: 03/22/2021)
The Logic board houses 2 computers: a PIC32 microcontroller and a Raspberry PI 3B. The PIC32 controls the cooling system, drive state and communicates with various sensors to send data to the Raspberry Pi. The Raspberry Pi is used to run the SCADA system, which collects data from sensors all across the car, some of which are the Real-Time Clock module and Inertial Measurement Unit connected directly to the Logic board. This data is monitored to determine whether the SCADA system should interrupt the safety loop and shut the car down. The data is also formatted and displayed so it can be monitored by users.
Logic Board Documents
- Logic Design Archive (LINK)
Insulation Monitoring Device (IMD)
The IMD is a part purchased from a company called Bender. They make insulation monitoring devices like this specifically for electric vehicle applications. The board actively monitors whether the high voltage system is electrically isolated from the rest of the car and can detect ground faults, which should interrupt the safety loop and shut the car down. The board we are using is an Isometer(R) IR155-3204.
The CarMan enclosure is what physically holds all of the boards within the manager, along with a few other parts such as the motor controller and SCADA display.
- Panel Drawings
- Electronics Panel Drawings:
- User Manual (PDF)
Subsystem TRL Chart
|TRL||What does this look like?||Expected Completion Date|
|9||Tested in competition||05/05/22|
|8||Tested and in working order for competition||04/15/22|
|7||Fully assembled and driven at Metzgar||02/25/22|
|6||Tested and worked with all subsystems on the chassis||02/04/22|
|5||Tested and worked with relevant subsystems in the dyno room||12/10/21|
|4||Tested and worked alone in the lab||11/19/21|
|3||Prototype board made||Completed|
|2||Design of board completed||Completed|
|1||Scope of requirements for system formulated