- Joined
- Mar 26, 2018

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- 2,554

Hi All,

Some of you may have seen me write about how much I am interested in industrial robotics. I've been looking for an old robot to play with for 3-4 years now and one just happened to pop up!

Many people are familiar with the 6 axis articulated robots that are often shown in factories (and I'd love one of those to play with) but what I happened across is a 4 axis SCARA (Selective Compliance Articulated Robot Arm) robot. These are very high speed robots that are typically used in pick and place assembly applications. Using robot kinematics it can translate in 3 axis (X, Y, & Z) as well as rotate the end effector around the Z axis. The one I bought is a rather large for this type of robot and while I don't yet have a manual to reference, I expect the payload to be in the 5-8kg range. Positioning resolution is typically .0001" or better on these units.

The robot did not come with a control (hence why it was so cheap), but I have a lot of industrial controls equipment including servo drives and a PLC capable of controlling motion and doing the inverse kinematic transformations required to control these devices. I intend to build a control from scratch. I bought this knowing full well that there are a ton of unknowns to getting it to work, but that is the fun part to me!

Here is the information I do know: Updated 12/13/2020

Note: The TT8800 is the largest robot in the family of "TT8xxx" SCARA robots. The TT8450, TT8550, and TT8700 had reduced reach, speeds, and payload capacities. The TT8450 also weighed 57 lbs which might have been a bit more reasonable for home use...

These would have come with a 19" rack mounted controller, a terminal keyboard, and a teach pendant.

I know this isn't exactly a machining project, but I think that some might enjoy following along and I really enjoy sharing my projects with this community. I will post lots of updates as I work through getting this guy running again.

-Mike

EDIT: Wanted to give a big shout out to my loving wife who completely took it in stride when I asked if she wouldn't mind a robot coming into the house

EDIT 5/5/2020: Data updated based on manuals kindly provided by Epson Robotics.

EDIT 5/6/2020: Data updated based on Yaskawa servo manuals and tech support.

EDIT: 5/7/2020: Added additional motor parameters I need to figure out. Added data on home sensors and motor brake.

EDIT: 5/8/2020: Added values to some of the new motor parameters. T1 is almost complete.

EDIT: 5/12/2020: Added info about EPSON being the robot Mfg. Edited encoder description.

EDIT: 5/19/2020: Corrected information on motor encoder. Added all missing motor parameters! Thanks Yaskawa!

EDIT: 9/14/2020: Added Z axis / T3 motor mechanics details.

EDIT: 9/15/2020: Added U axis / T4 motor mechanics details.

EDIT: 9/24/2020: Corrected the U Axis belt tension requirement

EDIT: 12/13/2020: Corrected T2 gear ratio. Added Harmonic Drive part numbers.

Some of you may have seen me write about how much I am interested in industrial robotics. I've been looking for an old robot to play with for 3-4 years now and one just happened to pop up!

Many people are familiar with the 6 axis articulated robots that are often shown in factories (and I'd love one of those to play with) but what I happened across is a 4 axis SCARA (Selective Compliance Articulated Robot Arm) robot. These are very high speed robots that are typically used in pick and place assembly applications. Using robot kinematics it can translate in 3 axis (X, Y, & Z) as well as rotate the end effector around the Z axis. The one I bought is a rather large for this type of robot and while I don't yet have a manual to reference, I expect the payload to be in the 5-8kg range. Positioning resolution is typically .0001" or better on these units.

The robot did not come with a control (hence why it was so cheap), but I have a lot of industrial controls equipment including servo drives and a PLC capable of controlling motion and doing the inverse kinematic transformations required to control these devices. I intend to build a control from scratch. I bought this knowing full well that there are a ton of unknowns to getting it to work, but that is the fun part to me!

Here is the information I do know: Updated 12/13/2020

**General:**- Manufacturer: EPSON Robotics - Model "BL" OEM Licensed to Seiko Instruments USA
- Model: D-TRAN TT8800
- Year Mfg.: 1999
- Seiko Instruments USA robotics division sold to Epson in 2001
- No. of Axes: 4
- Weight: 60kg (132lbs)

**Reach/Payload:**- Reach: 31.5 max 11.4" min
- Payload 2kg Rated (Full Speed) 10kg Max
- T1 Range: +/- 100 degrees
- T2 Range: +/- 140 degrees
- Z Stroke: 150mm (5.9"). There was an option available for 300mm stroke but I don't have it. It imposed some significant restrictions on motion speed due to the bending moment on the ballscrew.
- U Range: Continuous

**Positioning:**- T1 Range Encoder Counts: 455,113
- T2 Range Encoder Counts: 497,150
- Z Stroke Encoder Counts: 98304
- U Revolution Encoder Counts: 344,064
- Axes can be limited in range with adjustable hard stops
- Max Positioning speed (XY): 5180mm/s (12236 in/min or 11.6 mph)
- Max Positioning speed (Z): 937mm/s (2213 in/min or 2.1 mph)
- Max Positioning speed (U): 1140 deg/sec (190 RPM)
- Positioning Repeatability (XY): 0.025mm (0.00098")
- Positioning Repeatability (z): 0.020mm (0.00078")
- Z Axis Down Force: 150N (33.7 lbf)

**Motors:**- Motor Type: Yaskawa Sigma Series SGM AC servo.
- T1: SGM-04A3SU12 400W (Functionally identical to SGM-04A312)
- T2: SGM-02A3SU12, 200W (Functionally identical to SGM-02A312)
- Z: SGM-02A3SU21, 200W with 24VDC integral brake (Functionally identical to SGM-02A321)
- U: SGM-01A3SU11, 100W (Functionally identical to SGM-01A311). The gearbox pinion is a separate component and is not machined into the motor shaft as stated previously.
- Motor Encoder: Yaskawa TRD-Y2048 (UTOPE-20ANK). 2048 pulse per revolution Incremental Differential Quadrature signals with digitally multiplexed commutation and index signals. Yaskawa proprietary signals. Encoders are designed specifically for 6 step commutation on an 8 pole motor.
- Motor Brake: Z axis only - power to release. Voltage: 24VDC. Manual release button on top of robot.

**Mechanical:**- Gearbox Design: T1 & T2 - Harmonic Drive, Z - Timing belt reduction, U - Planetary Gearbox
- Z/C Axis: Ballscrew/ball spline drive, dual motor belt drive. THK KX series. Pitch unknown. 18mm through bore.
- T1 Gear Ratio: Harmonic Drive 100:1 (Calculated from encoder pulses). Harmonic drive model 52-100-960006
- T2 Gear Ratio: Harmonic Drive 80:1 (Calculated from encoder pulses). Harmonic drive model 25-80-960007
- Z Travel Ratio: Timing Belt Ratio 2:1 (36T motor, 72T Ballnut), Screw lead 0.975"/rev , Motor mm/Rev: 24.765. This needs to be validated by dial indicator measurement. It is close but not exact.
- U Gear Ratio: Planetary Gearbox, Ratio 21:1, Timing Belt Ratio 1:1 (72T:72T)
- Z Axis Timing Belt: BANDO S3M327UK HE (HTD Tooth, 3mm pitch, Fiberglass, 327mm)
- U Axis Timing Belt: BANDO S3M564UK 1A (HTD Tooth, 3mm pitch, Fiberglass, 564mm)

**Maintenance:**- Grease: SK-1A
- Grease Harmonic Drives every 8000 hours of operation
- Tension Z axis belt to 5kgf
- Tension U axis belt to 5kgf

**Electrical/Pneumatic:**- Power connector: 16 pins (factory robot cable available for $50) JAE Electronics: JL05-6A20-29PC-A66F0
- Signal connector: MDR 68 Pin Hirose Electric Company: DX30A-68P
- Tool Connector: DB-15 Standard Density (30V AC/DC 3A)
- Air connection: (2) 6mm 85 psi max
- T1 Axis Home Sensor: Optical 24V (3 wire: Signal, +24V, DC COM)
- T2 Axis Home Sensor: Optical 24V (3 wire: Signal, +24V, DC COM)
- Z Axis Home Sensor: Sunx/Panasonic GXL-8F miniature inductive proximity sensor 12-24VDC NPN-NO, Sn: 1.8mm
- U Axis Home Sensor: Optical 24V (3 wire: Signal, +24V, DC COM)

**T1 Axis Motor Data - Complete:**- Rated Power (W): 400
- Torque Constant (N*m/A_rms): 0.533
- Rated Torque (N*m): 1.27
- Peak Torque (N*m): 3.82
- Inertia (Kg*m^2): 0.0000191
- Poles Per Revolution (n): 8
- Winding Resistance (Ohms): 2.46
- Winding Inductance (H): .015744
- Inductive Time Constant (ms): 6.4
- Rated Voltage (Volts): 200
- Rated Speed (RPM): 3000
- Maximum Speed (RPM): 4500
- Continuous Current (A): 2.6
- Peak Current (A): 8.0
- Damping Coefficient (N*m/(Rad/s)): 0.0
- Voltage Constant (V_rms/k_RPM): 32.21
- Overload Limit (%): 100.0
- Acceleration (Rev/s^2): 10600
- Thermal Model Parameters (Copied from AB Y-2012-2-H motor (460W 230V similar size)):
- Rth-we (C/W): 32.767
- Cth-we (W*s/C): 1
- Rth-wa (C/W): 1.3
- Cth-wa (W*s/C): 1338

- Flux Saturation Curve (% Nominal Inductance): Use 1.0 for all values (discussed in post #23)

**T2 Axis Motor Data - Complete:**- Rated Power (W): 200
- Torque Constant (N*m/A): 0.355
- Rated Torque (N(m): 0.637
- Peak Torque (N*m): 1.91
- Inertia (Kg*m^2): 0.0000123
- Poles Per Revolution (n): 8
- Winding Resistance (Ohms): 2.68
- Winding Inductance (H): 0.01404
- Inductive Time Constant (ms): 5.4
- Rated Voltage (Volts): 200
- Rated Speed (RPM): 3000
- Maximum Speed (RPM): 4500
- Continuous Current (Amps): 2.0
- Peak Current (Amps): 6.0
- Damping Coefficient (N*m/(Rad/s)): 0.0
- Voltage Constant (V_rms/k_RPM): 21.48
- Overload Limit (%): 100.0
- Acceleration (Rev/s^2): 8244
- Thermal Model Parameters (Copied from AB Y-2006-2-H motor (230W 230V similar size):
- Rth-we (C/W): 32.767
- Cth-we (W*s/C): 1
- Rth-wa (C/W): 1.3
- Cth-wa (W*s/C): 1062

- Flux Saturation Curve (% Nominal Inductance): Use 1.0 for all values (discussed in post #23)

**Z Axis Motor Data - Complete:**- Rated Power (W): 200
- Torque Constant (Nm/A): 0.355
- Rated Torque (Nm): 0.637
- Peak Torque (Nm): 1.91
- Inertia (Kg*m^2): 0.0000181
- Poles Per Revolution (n): 8
- Winding Resistance (Ohms): 2.68
- Winding Inductance (H): 0.01404
- Inductive Time Constant (ms): 5.4
- Rated Voltage (Volts): 200
- Rated Speed (RPM): 3000
- Maximum Speed (RPM): 4500
- Continuous Current (Amps): 2.0
- Peak Current (Amps): 6.0
- Damping Coefficient (N*m/(Rad/s)): 0.0
- Voltage Constant (V_rms/k_RPM): 21.48
- Overload Limit (%): 100.0
- Acceleration (Rev/s^2): 8244
- Thermal Model Parameters (Copied from AB Y-2006-2-H motor (230W 230V similar size):
- Rth-we (C/W): 32.767
- Cth-we (W*s/C): 1
- Rth-wa (C/W): 1.3
- Cth-wa (W*s/C): 1062

- Flux Saturation Curve (% Nominal Inductance): Use 1.0 for all values (discussed in post #23)

**U Axis Motor Data - Complete:**- Rated Power (W): 100
- Torque Constant (Nm/A): 0.408
- Rated Torque (Nm): 0.318
- Peak Torque (Nm): 0.96
- Inertia (Kg*m^2): 0.0000040
- Poles Per Revolution (n): 8
- Winding Resistance (Ohms): 13.98
- Winding Inductance (H): 0.026562
- Inductive Time Constant (ms): 1.9
- Rated Voltage (Volts): 200
- Rated Speed (RPM): 3000
- Maximum Speed (RPM): 4500
- Continuous Current (Amps): 0.87
- Peak Current (Amps): 2.8
- Damping Coefficient (N*m/(Rad/s)): 0.0
- Voltage Constant (V_rms/k_RPM): 24.25
- Overload Limit (%): 100.0
- Acceleration (Rev/s^2): 12653
- Thermal Model Parameters (Copied from AB Y-1003-2-H motor (120W 230V similar size):
- Rth-we (C/W): 32.767
- Cth-we (W*s/C): 1
- Rth-wa (C/W): 2.2
- Cth-wa (W*s/C): 382

- Flux Saturation Curve (% Nominal Inductance): Use 1.0 for all values (discussed in post #23)

Note: The TT8800 is the largest robot in the family of "TT8xxx" SCARA robots. The TT8450, TT8550, and TT8700 had reduced reach, speeds, and payload capacities. The TT8450 also weighed 57 lbs which might have been a bit more reasonable for home use...

These would have come with a 19" rack mounted controller, a terminal keyboard, and a teach pendant.

I know this isn't exactly a machining project, but I think that some might enjoy following along and I really enjoy sharing my projects with this community. I will post lots of updates as I work through getting this guy running again.

-Mike

EDIT: Wanted to give a big shout out to my loving wife who completely took it in stride when I asked if she wouldn't mind a robot coming into the house

EDIT 5/5/2020: Data updated based on manuals kindly provided by Epson Robotics.

EDIT 5/6/2020: Data updated based on Yaskawa servo manuals and tech support.

EDIT: 5/7/2020: Added additional motor parameters I need to figure out. Added data on home sensors and motor brake.

EDIT: 5/8/2020: Added values to some of the new motor parameters. T1 is almost complete.

EDIT: 5/12/2020: Added info about EPSON being the robot Mfg. Edited encoder description.

EDIT: 5/19/2020: Corrected information on motor encoder. Added all missing motor parameters! Thanks Yaskawa!

EDIT: 9/14/2020: Added Z axis / T3 motor mechanics details.

EDIT: 9/15/2020: Added U axis / T4 motor mechanics details.

EDIT: 9/24/2020: Corrected the U Axis belt tension requirement

EDIT: 12/13/2020: Corrected T2 gear ratio. Added Harmonic Drive part numbers.

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