SEGA Motion Simulator Restoration and Modernisation

Aim: Refurbishment and Safety Compliance of a Modified Sega R360 Flight Simulator for Research Applications.

Objective: To document the ongoing rebuilding process, safety verification, and adherence to engineering standards for the "Sega" flight simulator, a modified Sega R360. The simulator is being modernised for fine control of pitch and roll axis rotations, intended for non-invasive research on vestibular and ocular senses. This log details the current status, safety protocols reviewed, component checks, modifications performed, and outstanding work.

Background

• Water Ingress: Pre-lockdown water spillage rendered portions of original SEGA hardware inoperable. Decided to replace faulty circuitry with alternative components instead of attempting repairs on original damaged circuits.
• Motors: Two TOSHIBA RA12M motors identified (one per axis). Documentation for these motors unavailable from TOSHIBA UK or distributors. This is considered a potential issue for future troubleshooting, although initial assessment suggests it may not currently be necessary.
• Motion System Overview: SEGA simulator features two-axis 360-degree movement (pitch and roll). Original control system: Toshiba motor -> Tamagawa encoder -> IMDL400/4 servo drive -> Joystick control.
• New Controller Input: New controller manual indicates a limit of 20 analog input signals, compatibility with original joystick control remains to be verified.

Hazards

• 480V 3-phase supply identified.
• High voltages present within the equipment and connectors. Power must be removed and capacitors allowed to discharge for at least 5 minutes before any connector removal.
• Do not connect or disconnect while powered.
• Drive surfaces can reach high temperatures.

Acknowledgements

• Supplier KDPES (Ian Webdell - Sales, Adam Webdell - Technical Manager) provided information on resolver pinout.
• Wiring mistakes corrected with assistance from my predacessor, Edvards Rutkovskis.
• Michael Gresty (Professor at Imperial College) and Swinder Ubhi (Senior Radiotherapy Electronics Engineer) assisted in diagnostics.
• Aliexpress reverse image search used for component identification.
• SERAD (French manufacturer) provided no support.

1: Project Initiation and Current Status

The "Sega" flight simulator project involves the comprehensive rebuilding of a modified Sega R360 unit. The primary goal is to ensure its safe and precise operation for research purposes. As of this entry, the simulator is not yet in operational use and is actively undergoing reconstruction and safety enhancements.

2: Safety Standards and Compliance Review

A critical aspect of the refurbishment is adherence to relevant safety and engineering standards. The following standards and guidelines form the basis of the safety assessment and implementation:

2.1 Electrical Safety Standards Compliance:

The simulator's electrical systems are designed and being inspected for adherence to:

• BS EN 60204-1:2018: Safety of machinery – Electrical equipment of machines.
• BS EN 60364-1: Low-voltage electrical installations.
• BS 7430: Code of practice for protective earthing of electrical installations.

2.2 BS EN 60204-1:2018 Key Requirements Implemented/Reviewed:

This standard provides comprehensive safety requirements for the electrical equipment of machines. Specific points relevant to the Sega simulator include:

• Protection Against Electric Shock & Equipment Protection: Ensuring proper insulation, earthing, and protection against overcurrent. Exposed conductive parts are to be connected to the system earth. Insulation and interconnects are being inspected to ensure no exposed wires or potential short circuits.
• Wiring Practices: Cable clearance from moving parts is maintained at a minimum of 25mm, or fixed barriers are used where this is not practicable.
• Conduit and Fittings: Rigid metal conduit and fittings are specified to be of galvanised steel or a corrosion-resistant material suitable for the conditions, avoiding galvanic action between dissimilar metals.
• Brake Actuator Protection: Operation of overload and overcurrent protective devices for mechanical brake actuators must initiate simultaneous de-energisation (release) of associated machine actuators.
• Device Interconnection: Machine-mounted devices, where connected in series or parallel, are recommended to have connections made through terminals forming intermediate test points. These terminals must be conveniently placed, adequately protected, and documented on relevant diagrams.
• Signage: Electric shock hazard warning signs (ISO 7010-W012 ) are to be visibly placed on enclosures containing electrical equipment that could pose a risk. These signs will be affixed to the exterior upon completion of wiring. Exceptions for signage apply to enclosures with a supply disconnecting device, operator-machine interfaces, or single devices with their own enclosures.

2.3 BS EN 60364-1 Key Requirements Implemented/Reviewed:

This standard focuses on low-voltage electrical installations, outlining fundamental principles for safety and proper functioning.

• System Earthing: The Sega's 400V 3-phase AC supply circuit diagram for the IMDL400 servo drive indicates no neutral wire in this configuration. This points to a TN-C type earthing system. For TN-C systems, BS standards dictate that exposed conductive parts of the machine may be connected to the system earth, with additional earthing being optional.
  • In a TN-C system, the neutral and protective functions are combined into a single PEN (Protective Earthed Neutral) conductor. BS 7430:2011+A1:2015 recommends multiple connections to earth along the PEN conductor, with the source solidly earthed, due to the risk of exposed conductive parts rising to line-to-earth voltage if the neutral becomes open-circuit.
• Protection Measures: The standard addresses protection against electric shock, thermal effects, overcurrent, fault currents, and voltage disturbances.
• Design and Verification: It provides guidelines for the design, selection of electrical equipment, erection, and verification of electrical installations.

2.4 Manufacturer Safety Guidelines

The IMDL400 servo drive is a core component of the motion system.

• Handling and Installation: Only qualified personnel should handle the drive. Power must be disconnected and a five-minute waiting period observed before removing connectors due to high voltages. The drive should never be opened. It requires vertical installation in a clean, dry environment with sufficient airflow.
• Connections: Shielded cables are to be used for signal and motor connections. Proper grounding of the drive and motor is essential. Diodes should be added across loads on static digital outputs.
• Protective Features: The drive incorporates protection against overcurrent, motor overheating, abnormal temperatures, supply interruptions, overspeed, earth faults, incorrect phase sequence, and overvoltages. It is noted that the servo drive can be used as the protective monitoring device and can trigger the internal circuit breaker in the TN-C system configuration.
• Output Specifications: The output Q2 is an NPN open collector, with a maximum current of 100mA. The load must be connected between Q2 and +24Vdc.

While not specified as the primary drive, guidelines from other manufacturers like Delta provide useful context for AC drive safety:

• Power Disconnection: AC input power must be disconnected before any wiring to the AC motor drive is made.
• Capacitor Discharge: Hazardous voltages can remain in DC-link capacitors even after power-off (wait for the POWER LED to be OFF); do not touch internal circuits and components. Similar precautions apply to main circuit terminals even if the 3-phase AC motor is stopped.
• Static Sensitivity: PCBs contain highly sensitive MOS components requiring anti-static measures during handling.
• Grounding: The AC motor drive must be grounded using the ground terminal, complying with local laws.
• Environmental Conditions: Avoid installation in locations subject to high temperature, direct sunlight, or inflammables.
• Capacitor Maintenance: Electrolytic capacitors can degrade if left uncharged for extended periods. It's recommended to charge drives stored without power every 2 years for 3-4 hours, gradually increasing to the rated voltage using an adjustable AC power source.

3: System Component Status and Service Checks

The following service criteria outline the checks performed or scheduled for the Sega simulator's components:

4: Modifications and Upgrades Implemented

Several modifications have been undertaken to enhance safety and functionality:

• Servo Drive Relocation: The IMDL series Servo Drive has been moved from the Attendant's Control Station to a position closer to the motor itself.
• Removal of Attendant's Control Station: The entire Attendant's Control Station has been removed. This station contained mostly unused circuitry related to the simulator's original game functions and was constructed of wood, with excess wiring that posed a potential fire hazard.


• Planned Laser Curtain: To replace the missing Mat Switch, a laser curtain system is planned. A Finder 48 Series DPDT DIN rail mounted 24V DC relay (RS Stock No.: 623-7157 ) is under consideration for this implementation, which would allow for a circuit breaker to be triggered by the laser curtain.

5: System Testing and Performance Optimisation

Initial attempts at optimizing the speed loop using partial autotuning for the current loop were unsuccessful. However, after repeated retries, the partial autotune procedure was successfully completed. (Refer to "Tuning speed loop example.pdf" for visual data of test generator speed settings and oscilloscope readings during optimisation ).

7: Outstanding Issues and Future Work

The following items represent ongoing tasks and areas requiring further attention:

• Completion of Rebuild: The overall rebuilding process of the Sega simulator is ongoing.
• Master Controller: The Master Controller is yet to be developed and integrated.
• Servomotor Plugs: These require upgrading to ensure reliable and safe connections.
• Brake Circuit Connection: The brake circuit needs to be connected to its relay.
• Taper Lock Screws: Missing screws on the taper lock for the gearbox pinion gear must be installed.
• Safety Fence: A fence needs to be sourced and installed.
• Mat Switch/Laser Curtain: Implementation of the laser curtain system as a replacement for the mat switch is pending.
• Electrical Safety Signage: Electric shock hazard signs need to be affixed to the exterior of relevant enclosures once wiring is finalised.

Error Messages (IMDL Servo Drive):

Documented list of error codes (E01-E20) related to DC bus voltage, motor current, temperature, resolver faults, parameter errors, etc. These will be crucial for debugging.

Resolver and Power Issues

• Error codes E07 & E08 (power and resolver fault) were prevalent.
• Original wiring diagram (Figure 1) shows 10 resolver connections; motor only has 7 pins plus two potential thermal connectors.
• YD28 connectors identified as non-standard Chinese connectors. M33 external thread diameter noted.
• Motor opened, resolver connections mapped, Tamagawa TS2640N321E64 encoder identified. Datasheet obtained.
• Resolver pin assignments determined for YD28-7 socket: Ground, Cosine High/Low, Sine High/Low, Reference High/Low.
• SUBD 9-way female connector identified on drive side for resolver connections.
• Impedance testing of resolver wiring and new plugs/sockets conducted. Initial error code E08 persisted.
• External function generator and oscilloscope used to verify resolver connections. 7Vrms 10kHz sine wave applied to R1-R2, outputs S2-S4 & S1-S3 measured. Smooth amplitude changes observed while manually rotating motor shaft, indicating good connections.
• Old RS232 socket repurposed to connect resolver using IMDL guide pinout.

• Power supply to motor side X10 cable measured at 80V, a 12V trigger cable found disconnected.
• Serad controller kept displaying "E02" (Undervoltage Error). Swinder assisted in measuring 400V at various circuit points. The original Sega circuitry had deactivated relays blocking 3-phase power - 24V trigger connection to relays identified and reimplemented from newly installed 3-phase to DC power supply.

Motor Brake and Drive Controller Connections:

• Pitch motor break and drive controller required separate 24V power supply.
• New circular plugs (YD28-7, YD28-4, GX12) soldered onto old motor cables. Protective diode required near motor brake socket. Grounding continuity tests planned. Compatibility of old braking system static relay with new controller to be tested.
• Brake motor connection documented (24Vdc). Protection diodes are obligatory.

X1 - RJ45 Connection (PC to Controller):

• Firmware version compatibility between IMDL controller and IDPL software checked.
• RS232 to USB A converter purchased (FTDI Chip RS232 USB A Male to DB-9 Male Converter - Chipi-X) for full-handshake UART.
• Custom driver from Chipi-X manufacturer website may be required.
• Communication port allocation in IDPL to be configured using Windows device manager.
• RS PRO D-sub Adapter (Female 9 Way D-Sub to Female RJ45) can be used for adaptation.
• X1 connector pin assignments documented for RS232 communication.

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